| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- E X P _ C H 4 -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 1992-2022, Free Software Foundation, Inc. -- |
| -- -- |
| -- GNAT is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 3, or (at your option) any later ver- -- |
| -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- |
| -- for more details. You should have received a copy of the GNU General -- |
| -- Public License distributed with GNAT; see file COPYING3. If not, go to -- |
| -- http://www.gnu.org/licenses for a complete copy of the license. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| with Aspects; use Aspects; |
| with Atree; use Atree; |
| with Checks; use Checks; |
| with Debug; use Debug; |
| with Einfo; use Einfo; |
| with Einfo.Entities; use Einfo.Entities; |
| with Einfo.Utils; use Einfo.Utils; |
| with Elists; use Elists; |
| with Errout; use Errout; |
| with Exp_Aggr; use Exp_Aggr; |
| with Exp_Atag; use Exp_Atag; |
| with Exp_Ch3; use Exp_Ch3; |
| with Exp_Ch6; use Exp_Ch6; |
| with Exp_Ch7; use Exp_Ch7; |
| with Exp_Ch9; use Exp_Ch9; |
| with Exp_Disp; use Exp_Disp; |
| with Exp_Fixd; use Exp_Fixd; |
| with Exp_Intr; use Exp_Intr; |
| with Exp_Pakd; use Exp_Pakd; |
| with Exp_Tss; use Exp_Tss; |
| with Exp_Util; use Exp_Util; |
| with Freeze; use Freeze; |
| with Inline; use Inline; |
| with Lib; use Lib; |
| with Namet; use Namet; |
| with Nlists; use Nlists; |
| with Nmake; use Nmake; |
| with Opt; use Opt; |
| with Par_SCO; use Par_SCO; |
| with Restrict; use Restrict; |
| with Rident; use Rident; |
| with Rtsfind; use Rtsfind; |
| with Sem; use Sem; |
| with Sem_Aux; use Sem_Aux; |
| with Sem_Cat; use Sem_Cat; |
| with Sem_Ch3; use Sem_Ch3; |
| with Sem_Ch13; use Sem_Ch13; |
| with Sem_Eval; use Sem_Eval; |
| with Sem_Res; use Sem_Res; |
| with Sem_Type; use Sem_Type; |
| with Sem_Util; use Sem_Util; |
| with Sem_Warn; use Sem_Warn; |
| with Sinfo; use Sinfo; |
| with Sinfo.Nodes; use Sinfo.Nodes; |
| with Sinfo.Utils; use Sinfo.Utils; |
| with Snames; use Snames; |
| with Stand; use Stand; |
| with SCIL_LL; use SCIL_LL; |
| with Targparm; use Targparm; |
| with Tbuild; use Tbuild; |
| with Ttypes; use Ttypes; |
| with Uintp; use Uintp; |
| with Urealp; use Urealp; |
| with Validsw; use Validsw; |
| with Warnsw; use Warnsw; |
| |
| package body Exp_Ch4 is |
| |
| Too_Large_Length_For_Array : constant Unat := Uint_256; |
| -- Threshold from which we do not try to create static array temporaries in |
| -- order to eliminate dynamic stack allocations. |
| |
| ----------------------- |
| -- Local Subprograms -- |
| ----------------------- |
| |
| procedure Binary_Op_Validity_Checks (N : Node_Id); |
| pragma Inline (Binary_Op_Validity_Checks); |
| -- Performs validity checks for a binary operator |
| |
| procedure Build_Boolean_Array_Proc_Call |
| (N : Node_Id; |
| Op1 : Node_Id; |
| Op2 : Node_Id); |
| -- If a boolean array assignment can be done in place, build call to |
| -- corresponding library procedure. |
| |
| procedure Displace_Allocator_Pointer (N : Node_Id); |
| -- Ada 2005 (AI-251): Subsidiary procedure to Expand_N_Allocator and |
| -- Expand_Allocator_Expression. Allocating class-wide interface objects |
| -- this routine displaces the pointer to the allocated object to reference |
| -- the component referencing the corresponding secondary dispatch table. |
| |
| procedure Expand_Allocator_Expression (N : Node_Id); |
| -- Subsidiary to Expand_N_Allocator, for the case when the expression |
| -- is a qualified expression. |
| |
| procedure Expand_Array_Comparison (N : Node_Id); |
| -- This routine handles expansion of the comparison operators (N_Op_Lt, |
| -- N_Op_Le, N_Op_Gt, N_Op_Ge) when operating on an array type. The basic |
| -- code for these operators is similar, differing only in the details of |
| -- the actual comparison call that is made. Special processing (call a |
| -- run-time routine) |
| |
| function Expand_Array_Equality |
| (Nod : Node_Id; |
| Lhs : Node_Id; |
| Rhs : Node_Id; |
| Bodies : List_Id; |
| Typ : Entity_Id) return Node_Id; |
| -- Expand an array equality into a call to a function implementing this |
| -- equality, and a call to it. Loc is the location for the generated nodes. |
| -- Lhs and Rhs are the array expressions to be compared. Bodies is a list |
| -- on which to attach bodies of local functions that are created in the |
| -- process. It is the responsibility of the caller to insert those bodies |
| -- at the right place. Nod provides the Sloc value for the generated code. |
| -- Normally the types used for the generated equality routine are taken |
| -- from Lhs and Rhs. However, in some situations of generated code, the |
| -- Etype fields of Lhs and Rhs are not set yet. In such cases, Typ supplies |
| -- the type to be used for the formal parameters. |
| |
| procedure Expand_Boolean_Operator (N : Node_Id); |
| -- Common expansion processing for Boolean operators (And, Or, Xor) for the |
| -- case of array type arguments. |
| |
| procedure Expand_Nonbinary_Modular_Op (N : Node_Id); |
| -- When generating C code, convert nonbinary modular arithmetic operations |
| -- into code that relies on the front-end expansion of operator Mod. No |
| -- expansion is performed if N is not a nonbinary modular operand. |
| |
| procedure Expand_Short_Circuit_Operator (N : Node_Id); |
| -- Common expansion processing for short-circuit boolean operators |
| |
| procedure Expand_Compare_Minimize_Eliminate_Overflow (N : Node_Id); |
| -- Deal with comparison in MINIMIZED/ELIMINATED overflow mode. This is |
| -- where we allow comparison of "out of range" values. |
| |
| function Expand_Composite_Equality |
| (Nod : Node_Id; |
| Typ : Entity_Id; |
| Lhs : Node_Id; |
| Rhs : Node_Id) return Node_Id; |
| -- Local recursive function used to expand equality for nested composite |
| -- types. Used by Expand_Record/Array_Equality. Nod provides the Sloc value |
| -- for generated code. Lhs and Rhs are the left and right sides for the |
| -- comparison, and Typ is the type of the objects to compare. |
| |
| procedure Expand_Concatenate (Cnode : Node_Id; Opnds : List_Id); |
| -- Routine to expand concatenation of a sequence of two or more operands |
| -- (in the list Operands) and replace node Cnode with the result of the |
| -- concatenation. The operands can be of any appropriate type, and can |
| -- include both arrays and singleton elements. |
| |
| procedure Expand_Membership_Minimize_Eliminate_Overflow (N : Node_Id); |
| -- N is an N_In membership test mode, with the overflow check mode set to |
| -- MINIMIZED or ELIMINATED, and the type of the left operand is a signed |
| -- integer type. This is a case where top level processing is required to |
| -- handle overflow checks in subtrees. |
| |
| procedure Fixup_Universal_Fixed_Operation (N : Node_Id); |
| -- N is a N_Op_Divide or N_Op_Multiply node whose result is universal |
| -- fixed. We do not have such a type at runtime, so the purpose of this |
| -- routine is to find the real type by looking up the tree. We also |
| -- determine if the operation must be rounded. |
| |
| procedure Get_First_Index_Bounds (T : Entity_Id; Lo, Hi : out Uint); |
| -- T is an array whose index bounds are all known at compile time. Return |
| -- the value of the low and high bounds of the first index of T. |
| |
| function Get_Size_For_Range (Lo, Hi : Uint) return Uint; |
| -- Return the size of a small signed integer type covering Lo .. Hi, the |
| -- main goal being to return a size lower than that of standard types. |
| |
| procedure Insert_Dereference_Action (N : Node_Id); |
| -- N is an expression whose type is an access. When the type of the |
| -- associated storage pool is derived from Checked_Pool, generate a |
| -- call to the 'Dereference' primitive operation. |
| |
| function Make_Array_Comparison_Op |
| (Typ : Entity_Id; |
| Nod : Node_Id) return Node_Id; |
| -- Comparisons between arrays are expanded in line. This function produces |
| -- the body of the implementation of (a > b), where a and b are one- |
| -- dimensional arrays of some discrete type. The original node is then |
| -- expanded into the appropriate call to this function. Nod provides the |
| -- Sloc value for the generated code. |
| |
| function Make_Boolean_Array_Op |
| (Typ : Entity_Id; |
| N : Node_Id) return Node_Id; |
| -- Boolean operations on boolean arrays are expanded in line. This function |
| -- produce the body for the node N, which is (a and b), (a or b), or (a xor |
| -- b). It is used only the normal case and not the packed case. The type |
| -- involved, Typ, is the Boolean array type, and the logical operations in |
| -- the body are simple boolean operations. Note that Typ is always a |
| -- constrained type (the caller has ensured this by using |
| -- Convert_To_Actual_Subtype if necessary). |
| |
| function Minimized_Eliminated_Overflow_Check (N : Node_Id) return Boolean; |
| -- For signed arithmetic operations when the current overflow mode is |
| -- MINIMIZED or ELIMINATED, we must call Apply_Arithmetic_Overflow_Checks |
| -- as the first thing we do. We then return. We count on the recursive |
| -- apparatus for overflow checks to call us back with an equivalent |
| -- operation that is in CHECKED mode, avoiding a recursive entry into this |
| -- routine, and that is when we will proceed with the expansion of the |
| -- operator (e.g. converting X+0 to X, or X**2 to X*X). We cannot do |
| -- these optimizations without first making this check, since there may be |
| -- operands further down the tree that are relying on the recursive calls |
| -- triggered by the top level nodes to properly process overflow checking |
| -- and remaining expansion on these nodes. Note that this call back may be |
| -- skipped if the operation is done in Bignum mode but that's fine, since |
| -- the Bignum call takes care of everything. |
| |
| procedure Narrow_Large_Operation (N : Node_Id); |
| -- Try to compute the result of a large operation in a narrower type than |
| -- its nominal type. This is mainly aimed at getting rid of operations done |
| -- in Universal_Integer that can be generated for attributes. |
| |
| procedure Optimize_Length_Comparison (N : Node_Id); |
| -- Given an expression, if it is of the form X'Length op N (or the other |
| -- way round), where N is known at compile time to be 0 or 1, or something |
| -- else where the value is known to be nonnegative and in the 32-bit range, |
| -- and X is a simple entity, and op is a comparison operator, optimizes it |
| -- into a comparison of X'First and X'Last. |
| |
| procedure Process_If_Case_Statements (N : Node_Id; Stmts : List_Id); |
| -- Inspect and process statement list Stmt of if or case expression N for |
| -- transient objects. If such objects are found, the routine generates code |
| -- to clean them up when the context of the expression is evaluated. |
| |
| procedure Process_Transient_In_Expression |
| (Obj_Decl : Node_Id; |
| Expr : Node_Id; |
| Stmts : List_Id); |
| -- Subsidiary routine to the expansion of expression_with_actions, if and |
| -- case expressions. Generate all necessary code to finalize a transient |
| -- object when the enclosing context is elaborated or evaluated. Obj_Decl |
| -- denotes the declaration of the transient object, which is usually the |
| -- result of a controlled function call. Expr denotes the expression with |
| -- actions, if expression, or case expression node. Stmts denotes the |
| -- statement list which contains Decl, either at the top level or within a |
| -- nested construct. |
| |
| procedure Rewrite_Comparison (N : Node_Id); |
| -- If N is the node for a comparison whose outcome can be determined at |
| -- compile time, then the node N can be rewritten with True or False. If |
| -- the outcome cannot be determined at compile time, the call has no |
| -- effect. If N is a type conversion, then this processing is applied to |
| -- its expression. If N is neither comparison nor a type conversion, the |
| -- call has no effect. |
| |
| procedure Tagged_Membership |
| (N : Node_Id; |
| SCIL_Node : out Node_Id; |
| Result : out Node_Id); |
| -- Construct the expression corresponding to the tagged membership test. |
| -- Deals with a second operand being (or not) a class-wide type. |
| |
| function Safe_In_Place_Array_Op |
| (Lhs : Node_Id; |
| Op1 : Node_Id; |
| Op2 : Node_Id) return Boolean; |
| -- In the context of an assignment, where the right-hand side is a boolean |
| -- operation on arrays, check whether operation can be performed in place. |
| |
| procedure Unary_Op_Validity_Checks (N : Node_Id); |
| pragma Inline (Unary_Op_Validity_Checks); |
| -- Performs validity checks for a unary operator |
| |
| ------------------------------- |
| -- Binary_Op_Validity_Checks -- |
| ------------------------------- |
| |
| procedure Binary_Op_Validity_Checks (N : Node_Id) is |
| begin |
| if Validity_Checks_On and Validity_Check_Operands then |
| Ensure_Valid (Left_Opnd (N)); |
| Ensure_Valid (Right_Opnd (N)); |
| end if; |
| end Binary_Op_Validity_Checks; |
| |
| ------------------------------------ |
| -- Build_Boolean_Array_Proc_Call -- |
| ------------------------------------ |
| |
| procedure Build_Boolean_Array_Proc_Call |
| (N : Node_Id; |
| Op1 : Node_Id; |
| Op2 : Node_Id) |
| is |
| Loc : constant Source_Ptr := Sloc (N); |
| Kind : constant Node_Kind := Nkind (Expression (N)); |
| Target : constant Node_Id := |
| Make_Attribute_Reference (Loc, |
| Prefix => Name (N), |
| Attribute_Name => Name_Address); |
| |
| Arg1 : Node_Id := Op1; |
| Arg2 : Node_Id := Op2; |
| Call_Node : Node_Id; |
| Proc_Name : Entity_Id; |
| |
| begin |
| if Kind = N_Op_Not then |
| if Nkind (Op1) in N_Binary_Op then |
| |
| -- Use negated version of the binary operators |
| |
| if Nkind (Op1) = N_Op_And then |
| Proc_Name := RTE (RE_Vector_Nand); |
| |
| elsif Nkind (Op1) = N_Op_Or then |
| Proc_Name := RTE (RE_Vector_Nor); |
| |
| else pragma Assert (Nkind (Op1) = N_Op_Xor); |
| Proc_Name := RTE (RE_Vector_Xor); |
| end if; |
| |
| Call_Node := |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (Proc_Name, Loc), |
| |
| Parameter_Associations => New_List ( |
| Target, |
| Make_Attribute_Reference (Loc, |
| Prefix => Left_Opnd (Op1), |
| Attribute_Name => Name_Address), |
| |
| Make_Attribute_Reference (Loc, |
| Prefix => Right_Opnd (Op1), |
| Attribute_Name => Name_Address), |
| |
| Make_Attribute_Reference (Loc, |
| Prefix => Left_Opnd (Op1), |
| Attribute_Name => Name_Length))); |
| |
| else |
| Proc_Name := RTE (RE_Vector_Not); |
| |
| Call_Node := |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (Proc_Name, Loc), |
| Parameter_Associations => New_List ( |
| Target, |
| |
| Make_Attribute_Reference (Loc, |
| Prefix => Op1, |
| Attribute_Name => Name_Address), |
| |
| Make_Attribute_Reference (Loc, |
| Prefix => Op1, |
| Attribute_Name => Name_Length))); |
| end if; |
| |
| else |
| -- We use the following equivalences: |
| |
| -- (not X) or (not Y) = not (X and Y) = Nand (X, Y) |
| -- (not X) and (not Y) = not (X or Y) = Nor (X, Y) |
| -- (not X) xor (not Y) = X xor Y |
| -- X xor (not Y) = not (X xor Y) = Nxor (X, Y) |
| |
| if Nkind (Op1) = N_Op_Not then |
| Arg1 := Right_Opnd (Op1); |
| Arg2 := Right_Opnd (Op2); |
| |
| if Kind = N_Op_And then |
| Proc_Name := RTE (RE_Vector_Nor); |
| elsif Kind = N_Op_Or then |
| Proc_Name := RTE (RE_Vector_Nand); |
| else |
| Proc_Name := RTE (RE_Vector_Xor); |
| end if; |
| |
| else |
| if Kind = N_Op_And then |
| Proc_Name := RTE (RE_Vector_And); |
| elsif Kind = N_Op_Or then |
| Proc_Name := RTE (RE_Vector_Or); |
| elsif Nkind (Op2) = N_Op_Not then |
| Proc_Name := RTE (RE_Vector_Nxor); |
| Arg2 := Right_Opnd (Op2); |
| else |
| Proc_Name := RTE (RE_Vector_Xor); |
| end if; |
| end if; |
| |
| Call_Node := |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (Proc_Name, Loc), |
| Parameter_Associations => New_List ( |
| Target, |
| Make_Attribute_Reference (Loc, |
| Prefix => Arg1, |
| Attribute_Name => Name_Address), |
| Make_Attribute_Reference (Loc, |
| Prefix => Arg2, |
| Attribute_Name => Name_Address), |
| Make_Attribute_Reference (Loc, |
| Prefix => Arg1, |
| Attribute_Name => Name_Length))); |
| end if; |
| |
| Rewrite (N, Call_Node); |
| Analyze (N); |
| |
| exception |
| when RE_Not_Available => |
| return; |
| end Build_Boolean_Array_Proc_Call; |
| |
| ----------------------- |
| -- Build_Eq_Call -- |
| ----------------------- |
| |
| function Build_Eq_Call |
| (Typ : Entity_Id; |
| Loc : Source_Ptr; |
| Lhs : Node_Id; |
| Rhs : Node_Id) return Node_Id |
| is |
| Eq : constant Entity_Id := Get_User_Defined_Equality (Typ); |
| |
| begin |
| if Present (Eq) then |
| if Is_Abstract_Subprogram (Eq) then |
| return Make_Raise_Program_Error (Loc, |
| Reason => PE_Explicit_Raise); |
| |
| else |
| return |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Eq, Loc), |
| Parameter_Associations => New_List (Lhs, Rhs)); |
| end if; |
| end if; |
| |
| -- If not found, predefined operation will be used |
| |
| return Empty; |
| end Build_Eq_Call; |
| |
| -------------------------------- |
| -- Displace_Allocator_Pointer -- |
| -------------------------------- |
| |
| procedure Displace_Allocator_Pointer (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Orig_Node : constant Node_Id := Original_Node (N); |
| Dtyp : Entity_Id; |
| Etyp : Entity_Id; |
| PtrT : Entity_Id; |
| |
| begin |
| -- Do nothing in case of VM targets: the virtual machine will handle |
| -- interfaces directly. |
| |
| if not Tagged_Type_Expansion then |
| return; |
| end if; |
| |
| pragma Assert (Nkind (N) = N_Identifier |
| and then Nkind (Orig_Node) = N_Allocator); |
| |
| PtrT := Etype (Orig_Node); |
| Dtyp := Available_View (Designated_Type (PtrT)); |
| Etyp := Etype (Expression (Orig_Node)); |
| |
| if Is_Class_Wide_Type (Dtyp) and then Is_Interface (Dtyp) then |
| |
| -- If the type of the allocator expression is not an interface type |
| -- we can generate code to reference the record component containing |
| -- the pointer to the secondary dispatch table. |
| |
| if not Is_Interface (Etyp) then |
| declare |
| Saved_Typ : constant Entity_Id := Etype (Orig_Node); |
| |
| begin |
| -- 1) Get access to the allocated object |
| |
| Rewrite (N, |
| Make_Explicit_Dereference (Loc, Relocate_Node (N))); |
| Set_Etype (N, Etyp); |
| Set_Analyzed (N); |
| |
| -- 2) Add the conversion to displace the pointer to reference |
| -- the secondary dispatch table. |
| |
| Rewrite (N, Convert_To (Dtyp, Relocate_Node (N))); |
| Analyze_And_Resolve (N, Dtyp); |
| |
| -- 3) The 'access to the secondary dispatch table will be used |
| -- as the value returned by the allocator. |
| |
| Rewrite (N, |
| Make_Attribute_Reference (Loc, |
| Prefix => Relocate_Node (N), |
| Attribute_Name => Name_Access)); |
| Set_Etype (N, Saved_Typ); |
| Set_Analyzed (N); |
| end; |
| |
| -- If the type of the allocator expression is an interface type we |
| -- generate a run-time call to displace "this" to reference the |
| -- component containing the pointer to the secondary dispatch table |
| -- or else raise Constraint_Error if the actual object does not |
| -- implement the target interface. This case corresponds to the |
| -- following example: |
| |
| -- function Op (Obj : Iface_1'Class) return access Iface_2'Class is |
| -- begin |
| -- return new Iface_2'Class'(Obj); |
| -- end Op; |
| |
| else |
| Rewrite (N, |
| Unchecked_Convert_To (PtrT, |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (RTE (RE_Displace), Loc), |
| Parameter_Associations => New_List ( |
| Unchecked_Convert_To (RTE (RE_Address), |
| Relocate_Node (N)), |
| |
| New_Occurrence_Of |
| (Elists.Node |
| (First_Elmt |
| (Access_Disp_Table (Etype (Base_Type (Dtyp))))), |
| Loc))))); |
| Analyze_And_Resolve (N, PtrT); |
| end if; |
| end if; |
| end Displace_Allocator_Pointer; |
| |
| --------------------------------- |
| -- Expand_Allocator_Expression -- |
| --------------------------------- |
| |
| procedure Expand_Allocator_Expression (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Exp : constant Node_Id := Expression (Expression (N)); |
| PtrT : constant Entity_Id := Etype (N); |
| DesigT : constant Entity_Id := Designated_Type (PtrT); |
| |
| procedure Apply_Accessibility_Check |
| (Ref : Node_Id; |
| Built_In_Place : Boolean := False); |
| -- Ada 2005 (AI-344): For an allocator with a class-wide designated |
| -- type, generate an accessibility check to verify that the level of the |
| -- type of the created object is not deeper than the level of the access |
| -- type. If the type of the qualified expression is class-wide, then |
| -- always generate the check (except in the case where it is known to be |
| -- unnecessary, see comment below). Otherwise, only generate the check |
| -- if the level of the qualified expression type is statically deeper |
| -- than the access type. |
| -- |
| -- Although the static accessibility will generally have been performed |
| -- as a legality check, it won't have been done in cases where the |
| -- allocator appears in generic body, so a run-time check is needed in |
| -- general. One special case is when the access type is declared in the |
| -- same scope as the class-wide allocator, in which case the check can |
| -- never fail, so it need not be generated. |
| -- |
| -- As an open issue, there seem to be cases where the static level |
| -- associated with the class-wide object's underlying type is not |
| -- sufficient to perform the proper accessibility check, such as for |
| -- allocators in nested subprograms or accept statements initialized by |
| -- class-wide formals when the actual originates outside at a deeper |
| -- static level. The nested subprogram case might require passing |
| -- accessibility levels along with class-wide parameters, and the task |
| -- case seems to be an actual gap in the language rules that needs to |
| -- be fixed by the ARG. ??? |
| |
| ------------------------------- |
| -- Apply_Accessibility_Check -- |
| ------------------------------- |
| |
| procedure Apply_Accessibility_Check |
| (Ref : Node_Id; |
| Built_In_Place : Boolean := False) |
| is |
| Pool_Id : constant Entity_Id := Associated_Storage_Pool (PtrT); |
| Cond : Node_Id; |
| Fin_Call : Node_Id; |
| Free_Stmt : Node_Id; |
| Obj_Ref : Node_Id; |
| Stmts : List_Id; |
| |
| begin |
| if Ada_Version >= Ada_2005 |
| and then Is_Class_Wide_Type (DesigT) |
| and then Tagged_Type_Expansion |
| and then not Scope_Suppress.Suppress (Accessibility_Check) |
| and then not No_Dynamic_Accessibility_Checks_Enabled (Ref) |
| and then |
| (Type_Access_Level (Etype (Exp)) > Type_Access_Level (PtrT) |
| or else |
| (Is_Class_Wide_Type (Etype (Exp)) |
| and then Scope (PtrT) /= Current_Scope)) |
| then |
| -- If the allocator was built in place, Ref is already a reference |
| -- to the access object initialized to the result of the allocator |
| -- (see Exp_Ch6.Make_Build_In_Place_Call_In_Allocator). We call |
| -- Remove_Side_Effects for cases where the build-in-place call may |
| -- still be the prefix of the reference (to avoid generating |
| -- duplicate calls). Otherwise, it is the entity associated with |
| -- the object containing the address of the allocated object. |
| |
| if Built_In_Place then |
| Remove_Side_Effects (Ref); |
| Obj_Ref := New_Copy_Tree (Ref); |
| else |
| Obj_Ref := New_Occurrence_Of (Ref, Loc); |
| end if; |
| |
| -- For access to interface types we must generate code to displace |
| -- the pointer to the base of the object since the subsequent code |
| -- references components located in the TSD of the object (which |
| -- is associated with the primary dispatch table --see a-tags.ads) |
| -- and also generates code invoking Free, which requires also a |
| -- reference to the base of the unallocated object. |
| |
| if Is_Interface (DesigT) and then Tagged_Type_Expansion then |
| Obj_Ref := |
| Unchecked_Convert_To (Etype (Obj_Ref), |
| Make_Function_Call (Loc, |
| Name => |
| New_Occurrence_Of (RTE (RE_Base_Address), Loc), |
| Parameter_Associations => New_List ( |
| Unchecked_Convert_To (RTE (RE_Address), |
| New_Copy_Tree (Obj_Ref))))); |
| end if; |
| |
| -- Step 1: Create the object clean up code |
| |
| Stmts := New_List; |
| |
| -- Deallocate the object if the accessibility check fails. This |
| -- is done only on targets or profiles that support deallocation. |
| |
| -- Free (Obj_Ref); |
| |
| if RTE_Available (RE_Free) then |
| Free_Stmt := Make_Free_Statement (Loc, New_Copy_Tree (Obj_Ref)); |
| Set_Storage_Pool (Free_Stmt, Pool_Id); |
| |
| Append_To (Stmts, Free_Stmt); |
| |
| -- The target or profile cannot deallocate objects |
| |
| else |
| Free_Stmt := Empty; |
| end if; |
| |
| -- Finalize the object if applicable. Generate: |
| |
| -- [Deep_]Finalize (Obj_Ref.all); |
| |
| if Needs_Finalization (DesigT) |
| and then not No_Heap_Finalization (PtrT) |
| then |
| Fin_Call := |
| Make_Final_Call |
| (Obj_Ref => |
| Make_Explicit_Dereference (Loc, New_Copy (Obj_Ref)), |
| Typ => DesigT); |
| |
| -- Guard against a missing [Deep_]Finalize when the designated |
| -- type was not properly frozen. |
| |
| if No (Fin_Call) then |
| Fin_Call := Make_Null_Statement (Loc); |
| end if; |
| |
| -- When the target or profile supports deallocation, wrap the |
| -- finalization call in a block to ensure proper deallocation |
| -- even if finalization fails. Generate: |
| |
| -- begin |
| -- <Fin_Call> |
| -- exception |
| -- when others => |
| -- <Free_Stmt> |
| -- raise; |
| -- end; |
| |
| if Present (Free_Stmt) then |
| Fin_Call := |
| Make_Block_Statement (Loc, |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List (Fin_Call), |
| |
| Exception_Handlers => New_List ( |
| Make_Exception_Handler (Loc, |
| Exception_Choices => New_List ( |
| Make_Others_Choice (Loc)), |
| Statements => New_List ( |
| New_Copy_Tree (Free_Stmt), |
| Make_Raise_Statement (Loc)))))); |
| end if; |
| |
| Prepend_To (Stmts, Fin_Call); |
| end if; |
| |
| -- Signal the accessibility failure through a Program_Error |
| |
| Append_To (Stmts, |
| Make_Raise_Program_Error (Loc, |
| Reason => PE_Accessibility_Check_Failed)); |
| |
| -- Step 2: Create the accessibility comparison |
| |
| -- Generate: |
| -- Ref'Tag |
| |
| Obj_Ref := |
| Make_Attribute_Reference (Loc, |
| Prefix => Obj_Ref, |
| Attribute_Name => Name_Tag); |
| |
| -- For tagged types, determine the accessibility level by looking |
| -- at the type specific data of the dispatch table. Generate: |
| |
| -- Type_Specific_Data (Address (Ref'Tag)).Access_Level |
| |
| if Tagged_Type_Expansion then |
| Cond := Build_Get_Access_Level (Loc, Obj_Ref); |
| |
| -- Use a runtime call to determine the accessibility level when |
| -- compiling on virtual machine targets. Generate: |
| |
| -- Get_Access_Level (Ref'Tag) |
| |
| else |
| Cond := |
| Make_Function_Call (Loc, |
| Name => |
| New_Occurrence_Of (RTE (RE_Get_Access_Level), Loc), |
| Parameter_Associations => New_List (Obj_Ref)); |
| end if; |
| |
| Cond := |
| Make_Op_Gt (Loc, |
| Left_Opnd => Cond, |
| Right_Opnd => Accessibility_Level (N, Dynamic_Level)); |
| |
| -- Due to the complexity and side effects of the check, utilize an |
| -- if statement instead of the regular Program_Error circuitry. |
| |
| Insert_Action (N, |
| Make_Implicit_If_Statement (N, |
| Condition => Cond, |
| Then_Statements => Stmts)); |
| end if; |
| end Apply_Accessibility_Check; |
| |
| -- Local variables |
| |
| Indic : constant Node_Id := Subtype_Mark (Expression (N)); |
| T : constant Entity_Id := Entity (Indic); |
| Adj_Call : Node_Id; |
| Aggr_In_Place : Boolean; |
| Node : Node_Id; |
| Tag_Assign : Node_Id; |
| Temp : Entity_Id; |
| Temp_Decl : Node_Id; |
| |
| TagT : Entity_Id := Empty; |
| -- Type used as source for tag assignment |
| |
| TagR : Node_Id := Empty; |
| -- Target reference for tag assignment |
| |
| -- Start of processing for Expand_Allocator_Expression |
| |
| begin |
| -- Handle call to C++ constructor |
| |
| if Is_CPP_Constructor_Call (Exp) then |
| Make_CPP_Constructor_Call_In_Allocator |
| (Allocator => N, |
| Function_Call => Exp); |
| return; |
| end if; |
| |
| -- If we have: |
| -- type A is access T1; |
| -- X : A := new T2'(...); |
| -- T1 and T2 can be different subtypes, and we might need to check |
| -- both constraints. First check against the type of the qualified |
| -- expression. |
| |
| Apply_Constraint_Check (Exp, T, No_Sliding => True); |
| |
| Apply_Predicate_Check (Exp, T); |
| |
| -- Check that any anonymous access discriminants are suitable |
| -- for use in an allocator. |
| |
| -- Note: This check is performed here instead of during analysis so that |
| -- we can check against the fully resolved etype of Exp. |
| |
| if Is_Entity_Name (Exp) |
| and then Has_Anonymous_Access_Discriminant (Etype (Exp)) |
| and then Static_Accessibility_Level (Exp, Object_Decl_Level) |
| > Static_Accessibility_Level (N, Object_Decl_Level) |
| then |
| -- A dynamic check and a warning are generated when we are within |
| -- an instance. |
| |
| if In_Instance then |
| Insert_Action (N, |
| Make_Raise_Program_Error (Loc, |
| Reason => PE_Accessibility_Check_Failed)); |
| |
| Error_Msg_Warn := SPARK_Mode /= On; |
| Error_Msg_N ("anonymous access discriminant is too deep for use" |
| & " in allocator<<", N); |
| Error_Msg_N ("\Program_Error [<<", N); |
| |
| -- Otherwise, make the error static |
| |
| else |
| Error_Msg_N ("anonymous access discriminant is too deep for use" |
| & " in allocator", N); |
| end if; |
| end if; |
| |
| if Do_Range_Check (Exp) then |
| Generate_Range_Check (Exp, T, CE_Range_Check_Failed); |
| end if; |
| |
| -- A check is also needed in cases where the designated subtype is |
| -- constrained and differs from the subtype given in the qualified |
| -- expression. Note that the check on the qualified expression does |
| -- not allow sliding, but this check does (a relaxation from Ada 83). |
| |
| if Is_Constrained (DesigT) |
| and then not Subtypes_Statically_Match (T, DesigT) |
| then |
| Apply_Constraint_Check (Exp, DesigT, No_Sliding => False); |
| |
| Apply_Predicate_Check (Exp, DesigT); |
| |
| if Do_Range_Check (Exp) then |
| Generate_Range_Check (Exp, DesigT, CE_Range_Check_Failed); |
| end if; |
| end if; |
| |
| if Nkind (Exp) = N_Raise_Constraint_Error then |
| Rewrite (N, New_Copy (Exp)); |
| Set_Etype (N, PtrT); |
| return; |
| end if; |
| |
| Aggr_In_Place := Is_Delayed_Aggregate (Exp); |
| |
| -- Case of tagged type or type requiring finalization |
| |
| if Is_Tagged_Type (T) or else Needs_Finalization (T) then |
| |
| -- Ada 2005 (AI-318-02): If the initialization expression is a call |
| -- to a build-in-place function, then access to the allocated object |
| -- must be passed to the function. |
| |
| if Is_Build_In_Place_Function_Call (Exp) then |
| Make_Build_In_Place_Call_In_Allocator (N, Exp); |
| Apply_Accessibility_Check (N, Built_In_Place => True); |
| return; |
| |
| -- Ada 2005 (AI-318-02): Specialization of the previous case for |
| -- expressions containing a build-in-place function call whose |
| -- returned object covers interface types, and Expr has calls to |
| -- Ada.Tags.Displace to displace the pointer to the returned build- |
| -- in-place object to reference the secondary dispatch table of a |
| -- covered interface type. |
| |
| elsif Present (Unqual_BIP_Iface_Function_Call (Exp)) then |
| Make_Build_In_Place_Iface_Call_In_Allocator (N, Exp); |
| Apply_Accessibility_Check (N, Built_In_Place => True); |
| return; |
| end if; |
| |
| -- Actions inserted before: |
| -- Temp : constant ptr_T := new T'(Expression); |
| -- Temp._tag = T'tag; -- when not class-wide |
| -- [Deep_]Adjust (Temp.all); |
| |
| -- We analyze by hand the new internal allocator to avoid any |
| -- recursion and inappropriate call to Initialize. |
| |
| -- We don't want to remove side effects when the expression must be |
| -- built in place. In the case of a build-in-place function call, |
| -- that could lead to a duplication of the call, which was already |
| -- substituted for the allocator. |
| |
| if not Aggr_In_Place then |
| Remove_Side_Effects (Exp); |
| end if; |
| |
| Temp := Make_Temporary (Loc, 'P', N); |
| |
| -- For a class wide allocation generate the following code: |
| |
| -- type Equiv_Record is record ... end record; |
| -- implicit subtype CW is <Class_Wide_Subytpe>; |
| -- temp : PtrT := new CW'(CW!(expr)); |
| |
| if Is_Class_Wide_Type (T) then |
| Expand_Subtype_From_Expr (Empty, T, Indic, Exp); |
| |
| -- Ada 2005 (AI-251): If the expression is a class-wide interface |
| -- object we generate code to move up "this" to reference the |
| -- base of the object before allocating the new object. |
| |
| -- Note that Exp'Address is recursively expanded into a call |
| -- to Base_Address (Exp.Tag) |
| |
| if Is_Class_Wide_Type (Etype (Exp)) |
| and then Is_Interface (Etype (Exp)) |
| and then Tagged_Type_Expansion |
| then |
| Set_Expression |
| (Expression (N), |
| Unchecked_Convert_To (Entity (Indic), |
| Make_Explicit_Dereference (Loc, |
| Unchecked_Convert_To (RTE (RE_Tag_Ptr), |
| Make_Attribute_Reference (Loc, |
| Prefix => Exp, |
| Attribute_Name => Name_Address))))); |
| else |
| Set_Expression |
| (Expression (N), |
| Unchecked_Convert_To (Entity (Indic), Exp)); |
| end if; |
| |
| Analyze_And_Resolve (Expression (N), Entity (Indic)); |
| end if; |
| |
| -- Processing for allocators returning non-interface types |
| |
| if not Is_Interface (Directly_Designated_Type (PtrT)) then |
| if Aggr_In_Place then |
| Temp_Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Object_Definition => New_Occurrence_Of (PtrT, Loc), |
| Expression => |
| Make_Allocator (Loc, |
| Expression => |
| New_Occurrence_Of (Etype (Exp), Loc))); |
| |
| -- Copy the Comes_From_Source flag for the allocator we just |
| -- built, since logically this allocator is a replacement of |
| -- the original allocator node. This is for proper handling of |
| -- restriction No_Implicit_Heap_Allocations. |
| |
| Preserve_Comes_From_Source |
| (Expression (Temp_Decl), N); |
| |
| Set_No_Initialization (Expression (Temp_Decl)); |
| Insert_Action (N, Temp_Decl); |
| |
| Build_Allocate_Deallocate_Proc (Temp_Decl, True); |
| Convert_Aggr_In_Allocator (N, Temp_Decl, Exp); |
| |
| else |
| Node := Relocate_Node (N); |
| Set_Analyzed (Node); |
| |
| Temp_Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Constant_Present => True, |
| Object_Definition => New_Occurrence_Of (PtrT, Loc), |
| Expression => Node); |
| |
| Insert_Action (N, Temp_Decl); |
| Build_Allocate_Deallocate_Proc (Temp_Decl, True); |
| end if; |
| |
| -- Ada 2005 (AI-251): Handle allocators whose designated type is an |
| -- interface type. In this case we use the type of the qualified |
| -- expression to allocate the object. |
| |
| else |
| declare |
| Def_Id : constant Entity_Id := Make_Temporary (Loc, 'T'); |
| New_Decl : Node_Id; |
| |
| begin |
| New_Decl := |
| Make_Full_Type_Declaration (Loc, |
| Defining_Identifier => Def_Id, |
| Type_Definition => |
| Make_Access_To_Object_Definition (Loc, |
| All_Present => True, |
| Null_Exclusion_Present => False, |
| Constant_Present => |
| Is_Access_Constant (Etype (N)), |
| Subtype_Indication => |
| New_Occurrence_Of (Etype (Exp), Loc))); |
| |
| Insert_Action (N, New_Decl); |
| |
| -- Inherit the allocation-related attributes from the original |
| -- access type. |
| |
| Set_Finalization_Master |
| (Def_Id, Finalization_Master (PtrT)); |
| |
| Set_Associated_Storage_Pool |
| (Def_Id, Associated_Storage_Pool (PtrT)); |
| |
| -- Declare the object using the previous type declaration |
| |
| if Aggr_In_Place then |
| Temp_Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Object_Definition => New_Occurrence_Of (Def_Id, Loc), |
| Expression => |
| Make_Allocator (Loc, |
| New_Occurrence_Of (Etype (Exp), Loc))); |
| |
| -- Copy the Comes_From_Source flag for the allocator we just |
| -- built, since logically this allocator is a replacement of |
| -- the original allocator node. This is for proper handling |
| -- of restriction No_Implicit_Heap_Allocations. |
| |
| Set_Comes_From_Source |
| (Expression (Temp_Decl), Comes_From_Source (N)); |
| |
| Set_No_Initialization (Expression (Temp_Decl)); |
| Insert_Action (N, Temp_Decl); |
| |
| Build_Allocate_Deallocate_Proc (Temp_Decl, True); |
| Convert_Aggr_In_Allocator (N, Temp_Decl, Exp); |
| |
| else |
| Node := Relocate_Node (N); |
| Set_Analyzed (Node); |
| |
| Temp_Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Constant_Present => True, |
| Object_Definition => New_Occurrence_Of (Def_Id, Loc), |
| Expression => Node); |
| |
| Insert_Action (N, Temp_Decl); |
| Build_Allocate_Deallocate_Proc (Temp_Decl, True); |
| end if; |
| |
| -- Generate an additional object containing the address of the |
| -- returned object. The type of this second object declaration |
| -- is the correct type required for the common processing that |
| -- is still performed by this subprogram. The displacement of |
| -- this pointer to reference the component associated with the |
| -- interface type will be done at the end of common processing. |
| |
| New_Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Make_Temporary (Loc, 'P'), |
| Object_Definition => New_Occurrence_Of (PtrT, Loc), |
| Expression => |
| Unchecked_Convert_To (PtrT, |
| New_Occurrence_Of (Temp, Loc))); |
| |
| Insert_Action (N, New_Decl); |
| |
| Temp_Decl := New_Decl; |
| Temp := Defining_Identifier (New_Decl); |
| end; |
| end if; |
| |
| -- Generate the tag assignment |
| |
| -- Suppress the tag assignment for VM targets because VM tags are |
| -- represented implicitly in objects. |
| |
| if not Tagged_Type_Expansion then |
| null; |
| |
| -- Ada 2005 (AI-251): Suppress the tag assignment with class-wide |
| -- interface objects because in this case the tag does not change. |
| |
| elsif Is_Interface (Directly_Designated_Type (Etype (N))) then |
| pragma Assert (Is_Class_Wide_Type |
| (Directly_Designated_Type (Etype (N)))); |
| null; |
| |
| elsif Is_Tagged_Type (T) and then not Is_Class_Wide_Type (T) then |
| TagT := T; |
| TagR := |
| Make_Explicit_Dereference (Loc, |
| Prefix => New_Occurrence_Of (Temp, Loc)); |
| |
| elsif Is_Private_Type (T) |
| and then Is_Tagged_Type (Underlying_Type (T)) |
| then |
| TagT := Underlying_Type (T); |
| TagR := |
| Unchecked_Convert_To (Underlying_Type (T), |
| Make_Explicit_Dereference (Loc, |
| Prefix => New_Occurrence_Of (Temp, Loc))); |
| end if; |
| |
| if Present (TagT) then |
| declare |
| Full_T : constant Entity_Id := Underlying_Type (TagT); |
| |
| begin |
| Tag_Assign := |
| Make_Assignment_Statement (Loc, |
| Name => |
| Make_Selected_Component (Loc, |
| Prefix => TagR, |
| Selector_Name => |
| New_Occurrence_Of |
| (First_Tag_Component (Full_T), Loc)), |
| |
| Expression => |
| Unchecked_Convert_To (RTE (RE_Tag), |
| New_Occurrence_Of |
| (Elists.Node |
| (First_Elmt (Access_Disp_Table (Full_T))), Loc))); |
| end; |
| |
| -- The previous assignment has to be done in any case |
| |
| Set_Assignment_OK (Name (Tag_Assign)); |
| Insert_Action (N, Tag_Assign); |
| end if; |
| |
| -- Generate an Adjust call if the object will be moved. In Ada 2005, |
| -- the object may be inherently limited, in which case there is no |
| -- Adjust procedure, and the object is built in place. In Ada 95, the |
| -- object can be limited but not inherently limited if this allocator |
| -- came from a return statement (we're allocating the result on the |
| -- secondary stack). In that case, the object will be moved, so we do |
| -- want to Adjust. However, if it's a nonlimited build-in-place |
| -- function call, Adjust is not wanted. |
| -- |
| -- Needs_Finalization (DesigT) can differ from Needs_Finalization (T) |
| -- if one of the two types is class-wide, and the other is not. |
| |
| if Needs_Finalization (DesigT) |
| and then Needs_Finalization (T) |
| and then not Aggr_In_Place |
| and then not Is_Limited_View (T) |
| and then not Alloc_For_BIP_Return (N) |
| and then not Is_Build_In_Place_Function_Call (Expression (N)) |
| then |
| -- An unchecked conversion is needed in the classwide case because |
| -- the designated type can be an ancestor of the subtype mark of |
| -- the allocator. |
| |
| Adj_Call := |
| Make_Adjust_Call |
| (Obj_Ref => |
| Unchecked_Convert_To (T, |
| Make_Explicit_Dereference (Loc, |
| Prefix => New_Occurrence_Of (Temp, Loc))), |
| Typ => T); |
| |
| if Present (Adj_Call) then |
| Insert_Action (N, Adj_Call); |
| end if; |
| end if; |
| |
| -- Note: the accessibility check must be inserted after the call to |
| -- [Deep_]Adjust to ensure proper completion of the assignment. |
| |
| Apply_Accessibility_Check (Temp); |
| |
| Rewrite (N, New_Occurrence_Of (Temp, Loc)); |
| Analyze_And_Resolve (N, PtrT); |
| |
| -- Ada 2005 (AI-251): Displace the pointer to reference the record |
| -- component containing the secondary dispatch table of the interface |
| -- type. |
| |
| if Is_Interface (Directly_Designated_Type (PtrT)) then |
| Displace_Allocator_Pointer (N); |
| end if; |
| |
| -- Always force the generation of a temporary for aggregates when |
| -- generating C code, to simplify the work in the code generator. |
| |
| elsif Aggr_In_Place |
| or else (Modify_Tree_For_C and then Nkind (Exp) = N_Aggregate) |
| then |
| Temp := Make_Temporary (Loc, 'P', N); |
| Temp_Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Object_Definition => New_Occurrence_Of (PtrT, Loc), |
| Expression => |
| Make_Allocator (Loc, |
| Expression => New_Occurrence_Of (Etype (Exp), Loc))); |
| |
| -- Copy the Comes_From_Source flag for the allocator we just built, |
| -- since logically this allocator is a replacement of the original |
| -- allocator node. This is for proper handling of restriction |
| -- No_Implicit_Heap_Allocations. |
| |
| Set_Comes_From_Source |
| (Expression (Temp_Decl), Comes_From_Source (N)); |
| |
| Set_No_Initialization (Expression (Temp_Decl)); |
| Insert_Action (N, Temp_Decl); |
| |
| Build_Allocate_Deallocate_Proc (Temp_Decl, True); |
| Convert_Aggr_In_Allocator (N, Temp_Decl, Exp); |
| |
| Rewrite (N, New_Occurrence_Of (Temp, Loc)); |
| Analyze_And_Resolve (N, PtrT); |
| |
| elsif Is_Access_Type (T) and then Can_Never_Be_Null (T) then |
| Install_Null_Excluding_Check (Exp); |
| |
| elsif Is_Access_Type (DesigT) |
| and then Nkind (Exp) = N_Allocator |
| and then Nkind (Expression (Exp)) /= N_Qualified_Expression |
| then |
| -- Apply constraint to designated subtype indication |
| |
| Apply_Constraint_Check |
| (Expression (Exp), Designated_Type (DesigT), No_Sliding => True); |
| |
| if Nkind (Expression (Exp)) = N_Raise_Constraint_Error then |
| |
| -- Propagate constraint_error to enclosing allocator |
| |
| Rewrite (Exp, New_Copy (Expression (Exp))); |
| end if; |
| |
| else |
| Build_Allocate_Deallocate_Proc (N, True); |
| |
| -- For an access to unconstrained packed array, GIGI needs to see an |
| -- expression with a constrained subtype in order to compute the |
| -- proper size for the allocator. |
| |
| if Is_Packed_Array (T) |
| and then not Is_Constrained (T) |
| then |
| declare |
| ConstrT : constant Entity_Id := Make_Temporary (Loc, 'A'); |
| Internal_Exp : constant Node_Id := Relocate_Node (Exp); |
| begin |
| Insert_Action (Exp, |
| Make_Subtype_Declaration (Loc, |
| Defining_Identifier => ConstrT, |
| Subtype_Indication => |
| Make_Subtype_From_Expr (Internal_Exp, T))); |
| Freeze_Itype (ConstrT, Exp); |
| Rewrite (Exp, OK_Convert_To (ConstrT, Internal_Exp)); |
| end; |
| end if; |
| |
| -- Ada 2005 (AI-318-02): If the initialization expression is a call |
| -- to a build-in-place function, then access to the allocated object |
| -- must be passed to the function. |
| |
| if Is_Build_In_Place_Function_Call (Exp) then |
| Make_Build_In_Place_Call_In_Allocator (N, Exp); |
| end if; |
| end if; |
| |
| exception |
| when RE_Not_Available => |
| return; |
| end Expand_Allocator_Expression; |
| |
| ----------------------------- |
| -- Expand_Array_Comparison -- |
| ----------------------------- |
| |
| -- Expansion is only required in the case of array types. For the unpacked |
| -- case, an appropriate runtime routine is called. For packed cases, and |
| -- also in some other cases where a runtime routine cannot be called, the |
| -- form of the expansion is: |
| |
| -- [body for greater_nn; boolean_expression] |
| |
| -- The body is built by Make_Array_Comparison_Op, and the form of the |
| -- Boolean expression depends on the operator involved. |
| |
| procedure Expand_Array_Comparison (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Op1 : Node_Id := Left_Opnd (N); |
| Op2 : Node_Id := Right_Opnd (N); |
| Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); |
| Ctyp : constant Entity_Id := Component_Type (Typ1); |
| |
| Expr : Node_Id; |
| Func_Body : Node_Id; |
| Func_Name : Entity_Id; |
| |
| Comp : RE_Id; |
| |
| Byte_Addressable : constant Boolean := System_Storage_Unit = Byte'Size; |
| -- True for byte addressable target |
| |
| function Length_Less_Than_4 (Opnd : Node_Id) return Boolean; |
| -- Returns True if the length of the given operand is known to be less |
| -- than 4. Returns False if this length is known to be four or greater |
| -- or is not known at compile time. |
| |
| ------------------------ |
| -- Length_Less_Than_4 -- |
| ------------------------ |
| |
| function Length_Less_Than_4 (Opnd : Node_Id) return Boolean is |
| Otyp : constant Entity_Id := Etype (Opnd); |
| |
| begin |
| if Ekind (Otyp) = E_String_Literal_Subtype then |
| return String_Literal_Length (Otyp) < 4; |
| |
| elsif Compile_Time_Known_Bounds (Otyp) then |
| declare |
| Lo, Hi : Uint; |
| |
| begin |
| Get_First_Index_Bounds (Otyp, Lo, Hi); |
| return Hi < Lo + 3; |
| end; |
| |
| else |
| return False; |
| end if; |
| end Length_Less_Than_4; |
| |
| -- Start of processing for Expand_Array_Comparison |
| |
| begin |
| -- Deal first with unpacked case, where we can call a runtime routine |
| -- except that we avoid this for targets for which are not addressable |
| -- by bytes. |
| |
| if not Is_Bit_Packed_Array (Typ1) and then Byte_Addressable then |
| -- The call we generate is: |
| |
| -- Compare_Array_xn[_Unaligned] |
| -- (left'address, right'address, left'length, right'length) <op> 0 |
| |
| -- x = U for unsigned, S for signed |
| -- n = 8,16,32,64,128 for component size |
| -- Add _Unaligned if length < 4 and component size is 8. |
| -- <op> is the standard comparison operator |
| |
| if Component_Size (Typ1) = 8 then |
| if Length_Less_Than_4 (Op1) |
| or else |
| Length_Less_Than_4 (Op2) |
| then |
| if Is_Unsigned_Type (Ctyp) then |
| Comp := RE_Compare_Array_U8_Unaligned; |
| else |
| Comp := RE_Compare_Array_S8_Unaligned; |
| end if; |
| |
| else |
| if Is_Unsigned_Type (Ctyp) then |
| Comp := RE_Compare_Array_U8; |
| else |
| Comp := RE_Compare_Array_S8; |
| end if; |
| end if; |
| |
| elsif Component_Size (Typ1) = 16 then |
| if Is_Unsigned_Type (Ctyp) then |
| Comp := RE_Compare_Array_U16; |
| else |
| Comp := RE_Compare_Array_S16; |
| end if; |
| |
| elsif Component_Size (Typ1) = 32 then |
| if Is_Unsigned_Type (Ctyp) then |
| Comp := RE_Compare_Array_U32; |
| else |
| Comp := RE_Compare_Array_S32; |
| end if; |
| |
| elsif Component_Size (Typ1) = 64 then |
| if Is_Unsigned_Type (Ctyp) then |
| Comp := RE_Compare_Array_U64; |
| else |
| Comp := RE_Compare_Array_S64; |
| end if; |
| |
| else pragma Assert (Component_Size (Typ1) = 128); |
| if Is_Unsigned_Type (Ctyp) then |
| Comp := RE_Compare_Array_U128; |
| else |
| Comp := RE_Compare_Array_S128; |
| end if; |
| end if; |
| |
| if RTE_Available (Comp) then |
| |
| -- Expand to a call only if the runtime function is available, |
| -- otherwise fall back to inline code. |
| |
| Remove_Side_Effects (Op1, Name_Req => True); |
| Remove_Side_Effects (Op2, Name_Req => True); |
| |
| Rewrite (Op1, |
| Make_Function_Call (Sloc (Op1), |
| Name => New_Occurrence_Of (RTE (Comp), Loc), |
| |
| Parameter_Associations => New_List ( |
| Make_Attribute_Reference (Loc, |
| Prefix => Relocate_Node (Op1), |
| Attribute_Name => Name_Address), |
| |
| Make_Attribute_Reference (Loc, |
| Prefix => Relocate_Node (Op2), |
| Attribute_Name => Name_Address), |
| |
| Make_Attribute_Reference (Loc, |
| Prefix => Relocate_Node (Op1), |
| Attribute_Name => Name_Length), |
| |
| Make_Attribute_Reference (Loc, |
| Prefix => Relocate_Node (Op2), |
| Attribute_Name => Name_Length)))); |
| |
| Rewrite (Op2, |
| Make_Integer_Literal (Sloc (Op2), |
| Intval => Uint_0)); |
| |
| Analyze_And_Resolve (Op1, Standard_Integer); |
| Analyze_And_Resolve (Op2, Standard_Integer); |
| return; |
| end if; |
| end if; |
| |
| -- Cases where we cannot make runtime call |
| |
| -- For (a <= b) we convert to not (a > b) |
| |
| if Chars (N) = Name_Op_Le then |
| Rewrite (N, |
| Make_Op_Not (Loc, |
| Right_Opnd => |
| Make_Op_Gt (Loc, |
| Left_Opnd => Op1, |
| Right_Opnd => Op2))); |
| Analyze_And_Resolve (N, Standard_Boolean); |
| return; |
| |
| -- For < the Boolean expression is |
| -- greater__nn (op2, op1) |
| |
| elsif Chars (N) = Name_Op_Lt then |
| Func_Body := Make_Array_Comparison_Op (Typ1, N); |
| |
| -- Switch operands |
| |
| Op1 := Right_Opnd (N); |
| Op2 := Left_Opnd (N); |
| |
| -- For (a >= b) we convert to not (a < b) |
| |
| elsif Chars (N) = Name_Op_Ge then |
| Rewrite (N, |
| Make_Op_Not (Loc, |
| Right_Opnd => |
| Make_Op_Lt (Loc, |
| Left_Opnd => Op1, |
| Right_Opnd => Op2))); |
| Analyze_And_Resolve (N, Standard_Boolean); |
| return; |
| |
| -- For > the Boolean expression is |
| -- greater__nn (op1, op2) |
| |
| else |
| pragma Assert (Chars (N) = Name_Op_Gt); |
| Func_Body := Make_Array_Comparison_Op (Typ1, N); |
| end if; |
| |
| Func_Name := Defining_Unit_Name (Specification (Func_Body)); |
| Expr := |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Func_Name, Loc), |
| Parameter_Associations => New_List (Op1, Op2)); |
| |
| Insert_Action (N, Func_Body); |
| Rewrite (N, Expr); |
| Analyze_And_Resolve (N, Standard_Boolean); |
| end Expand_Array_Comparison; |
| |
| --------------------------- |
| -- Expand_Array_Equality -- |
| --------------------------- |
| |
| -- Expand an equality function for multi-dimensional arrays. Here is an |
| -- example of such a function for Nb_Dimension = 2 |
| |
| -- function Enn (A : atyp; B : btyp) return boolean is |
| -- begin |
| -- if (A'length (1) = 0 or else A'length (2) = 0) |
| -- and then |
| -- (B'length (1) = 0 or else B'length (2) = 0) |
| -- then |
| -- return true; -- RM 4.5.2(22) |
| -- end if; |
| |
| -- if A'length (1) /= B'length (1) |
| -- or else |
| -- A'length (2) /= B'length (2) |
| -- then |
| -- return false; -- RM 4.5.2(23) |
| -- end if; |
| |
| -- declare |
| -- A1 : Index_T1 := A'first (1); |
| -- B1 : Index_T1 := B'first (1); |
| -- begin |
| -- loop |
| -- declare |
| -- A2 : Index_T2 := A'first (2); |
| -- B2 : Index_T2 := B'first (2); |
| -- begin |
| -- loop |
| -- if A (A1, A2) /= B (B1, B2) then |
| -- return False; |
| -- end if; |
| |
| -- exit when A2 = A'last (2); |
| -- A2 := Index_T2'succ (A2); |
| -- B2 := Index_T2'succ (B2); |
| -- end loop; |
| -- end; |
| |
| -- exit when A1 = A'last (1); |
| -- A1 := Index_T1'succ (A1); |
| -- B1 := Index_T1'succ (B1); |
| -- end loop; |
| -- end; |
| |
| -- return true; |
| -- end Enn; |
| |
| -- Note on the formal types used (atyp and btyp). If either of the arrays |
| -- is of a private type, we use the underlying type, and do an unchecked |
| -- conversion of the actual. If either of the arrays has a bound depending |
| -- on a discriminant, then we use the base type since otherwise we have an |
| -- escaped discriminant in the function. |
| |
| -- If both arrays are constrained and have the same bounds, we can generate |
| -- a loop with an explicit iteration scheme using a 'Range attribute over |
| -- the first array. |
| |
| function Expand_Array_Equality |
| (Nod : Node_Id; |
| Lhs : Node_Id; |
| Rhs : Node_Id; |
| Bodies : List_Id; |
| Typ : Entity_Id) return Node_Id |
| is |
| Loc : constant Source_Ptr := Sloc (Nod); |
| Decls : constant List_Id := New_List; |
| Index_List1 : constant List_Id := New_List; |
| Index_List2 : constant List_Id := New_List; |
| |
| First_Idx : Node_Id; |
| Formals : List_Id; |
| Func_Name : Entity_Id; |
| Func_Body : Node_Id; |
| |
| A : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uA); |
| B : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uB); |
| |
| Ltyp : Entity_Id; |
| Rtyp : Entity_Id; |
| -- The parameter types to be used for the formals |
| |
| New_Lhs : Node_Id; |
| New_Rhs : Node_Id; |
| -- The LHS and RHS converted to the parameter types |
| |
| function Arr_Attr |
| (Arr : Entity_Id; |
| Nam : Name_Id; |
| Dim : Pos) return Node_Id; |
| -- This builds the attribute reference Arr'Nam (Dim) |
| |
| function Component_Equality (Typ : Entity_Id) return Node_Id; |
| -- Create one statement to compare corresponding components, designated |
| -- by a full set of indexes. |
| |
| function Get_Arg_Type (N : Node_Id) return Entity_Id; |
| -- Given one of the arguments, computes the appropriate type to be used |
| -- for that argument in the corresponding function formal |
| |
| function Handle_One_Dimension |
| (N : Pos; |
| Index : Node_Id) return Node_Id; |
| -- This procedure returns the following code |
| -- |
| -- declare |
| -- An : Index_T := A'First (N); |
| -- Bn : Index_T := B'First (N); |
| -- begin |
| -- loop |
| -- xxx |
| -- exit when An = A'Last (N); |
| -- An := Index_T'Succ (An) |
| -- Bn := Index_T'Succ (Bn) |
| -- end loop; |
| -- end; |
| -- |
| -- If both indexes are constrained and identical, the procedure |
| -- returns a simpler loop: |
| -- |
| -- for An in A'Range (N) loop |
| -- xxx |
| -- end loop |
| -- |
| -- N is the dimension for which we are generating a loop. Index is the |
| -- N'th index node, whose Etype is Index_Type_n in the above code. The |
| -- xxx statement is either the loop or declare for the next dimension |
| -- or if this is the last dimension the comparison of corresponding |
| -- components of the arrays. |
| -- |
| -- The actual way the code works is to return the comparison of |
| -- corresponding components for the N+1 call. That's neater. |
| |
| function Test_Empty_Arrays return Node_Id; |
| -- This function constructs the test for both arrays being empty |
| -- (A'length (1) = 0 or else A'length (2) = 0 or else ...) |
| -- and then |
| -- (B'length (1) = 0 or else B'length (2) = 0 or else ...) |
| |
| function Test_Lengths_Correspond return Node_Id; |
| -- This function constructs the test for arrays having different lengths |
| -- in at least one index position, in which case the resulting code is: |
| |
| -- A'length (1) /= B'length (1) |
| -- or else |
| -- A'length (2) /= B'length (2) |
| -- or else |
| -- ... |
| |
| -------------- |
| -- Arr_Attr -- |
| -------------- |
| |
| function Arr_Attr |
| (Arr : Entity_Id; |
| Nam : Name_Id; |
| Dim : Pos) return Node_Id |
| is |
| begin |
| return |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Nam, |
| Prefix => New_Occurrence_Of (Arr, Loc), |
| Expressions => New_List (Make_Integer_Literal (Loc, Dim))); |
| end Arr_Attr; |
| |
| ------------------------ |
| -- Component_Equality -- |
| ------------------------ |
| |
| function Component_Equality (Typ : Entity_Id) return Node_Id is |
| Test : Node_Id; |
| L, R : Node_Id; |
| |
| begin |
| -- if a(i1...) /= b(j1...) then return false; end if; |
| |
| L := |
| Make_Indexed_Component (Loc, |
| Prefix => Make_Identifier (Loc, Chars (A)), |
| Expressions => Index_List1); |
| |
| R := |
| Make_Indexed_Component (Loc, |
| Prefix => Make_Identifier (Loc, Chars (B)), |
| Expressions => Index_List2); |
| |
| Test := Expand_Composite_Equality (Nod, Component_Type (Typ), L, R); |
| |
| -- If some (sub)component is an unchecked_union, the whole operation |
| -- will raise program error. |
| |
| if Nkind (Test) = N_Raise_Program_Error then |
| |
| -- This node is going to be inserted at a location where a |
| -- statement is expected: clear its Etype so analysis will set |
| -- it to the expected Standard_Void_Type. |
| |
| Set_Etype (Test, Empty); |
| return Test; |
| |
| else |
| return |
| Make_Implicit_If_Statement (Nod, |
| Condition => Make_Op_Not (Loc, Right_Opnd => Test), |
| Then_Statements => New_List ( |
| Make_Simple_Return_Statement (Loc, |
| Expression => New_Occurrence_Of (Standard_False, Loc)))); |
| end if; |
| end Component_Equality; |
| |
| ------------------ |
| -- Get_Arg_Type -- |
| ------------------ |
| |
| function Get_Arg_Type (N : Node_Id) return Entity_Id is |
| T : Entity_Id; |
| X : Node_Id; |
| |
| begin |
| T := Etype (N); |
| |
| if No (T) then |
| return Typ; |
| |
| else |
| T := Underlying_Type (T); |
| |
| X := First_Index (T); |
| while Present (X) loop |
| if Denotes_Discriminant (Type_Low_Bound (Etype (X))) |
| or else |
| Denotes_Discriminant (Type_High_Bound (Etype (X))) |
| then |
| T := Base_Type (T); |
| exit; |
| end if; |
| |
| Next_Index (X); |
| end loop; |
| |
| return T; |
| end if; |
| end Get_Arg_Type; |
| |
| -------------------------- |
| -- Handle_One_Dimension -- |
| --------------------------- |
| |
| function Handle_One_Dimension |
| (N : Pos; |
| Index : Node_Id) return Node_Id |
| is |
| Need_Separate_Indexes : constant Boolean := |
| Ltyp /= Rtyp or else not Is_Constrained (Ltyp); |
| -- If the index types are identical, and we are working with |
| -- constrained types, then we can use the same index for both |
| -- of the arrays. |
| |
| An : constant Entity_Id := Make_Temporary (Loc, 'A'); |
| |
| Bn : Entity_Id; |
| Index_T : Entity_Id; |
| Stm_List : List_Id; |
| Loop_Stm : Node_Id; |
| |
| begin |
| if N > Number_Dimensions (Ltyp) then |
| return Component_Equality (Ltyp); |
| end if; |
| |
| -- Case where we generate a loop |
| |
| Index_T := Base_Type (Etype (Index)); |
| |
| if Need_Separate_Indexes then |
| Bn := Make_Temporary (Loc, 'B'); |
| else |
| Bn := An; |
| end if; |
| |
| Append (New_Occurrence_Of (An, Loc), Index_List1); |
| Append (New_Occurrence_Of (Bn, Loc), Index_List2); |
| |
| Stm_List := New_List ( |
| Handle_One_Dimension (N + 1, Next_Index (Index))); |
| |
| if Need_Separate_Indexes then |
| |
| -- Generate guard for loop, followed by increments of indexes |
| |
| Append_To (Stm_List, |
| Make_Exit_Statement (Loc, |
| Condition => |
| Make_Op_Eq (Loc, |
| Left_Opnd => New_Occurrence_Of (An, Loc), |
| Right_Opnd => Arr_Attr (A, Name_Last, N)))); |
| |
| Append_To (Stm_List, |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (An, Loc), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Index_T, Loc), |
| Attribute_Name => Name_Succ, |
| Expressions => New_List ( |
| New_Occurrence_Of (An, Loc))))); |
| |
| Append_To (Stm_List, |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Bn, Loc), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Index_T, Loc), |
| Attribute_Name => Name_Succ, |
| Expressions => New_List ( |
| New_Occurrence_Of (Bn, Loc))))); |
| end if; |
| |
| -- If separate indexes, we need a declare block for An and Bn, and a |
| -- loop without an iteration scheme. |
| |
| if Need_Separate_Indexes then |
| Loop_Stm := |
| Make_Implicit_Loop_Statement (Nod, Statements => Stm_List); |
| |
| return |
| Make_Block_Statement (Loc, |
| Declarations => New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => An, |
| Object_Definition => New_Occurrence_Of (Index_T, Loc), |
| Expression => Arr_Attr (A, Name_First, N)), |
| |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Bn, |
| Object_Definition => New_Occurrence_Of (Index_T, Loc), |
| Expression => Arr_Attr (B, Name_First, N))), |
| |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List (Loop_Stm))); |
| |
| -- If no separate indexes, return loop statement with explicit |
| -- iteration scheme on its own. |
| |
| else |
| Loop_Stm := |
| Make_Implicit_Loop_Statement (Nod, |
| Statements => Stm_List, |
| Iteration_Scheme => |
| Make_Iteration_Scheme (Loc, |
| Loop_Parameter_Specification => |
| Make_Loop_Parameter_Specification (Loc, |
| Defining_Identifier => An, |
| Discrete_Subtype_Definition => |
| Arr_Attr (A, Name_Range, N)))); |
| return Loop_Stm; |
| end if; |
| end Handle_One_Dimension; |
| |
| ----------------------- |
| -- Test_Empty_Arrays -- |
| ----------------------- |
| |
| function Test_Empty_Arrays return Node_Id is |
| Alist : Node_Id := Empty; |
| Blist : Node_Id := Empty; |
| |
| begin |
| for J in 1 .. Number_Dimensions (Ltyp) loop |
| Evolve_Or_Else (Alist, |
| Make_Op_Eq (Loc, |
| Left_Opnd => Arr_Attr (A, Name_Length, J), |
| Right_Opnd => Make_Integer_Literal (Loc, Uint_0))); |
| |
| Evolve_Or_Else (Blist, |
| Make_Op_Eq (Loc, |
| Left_Opnd => Arr_Attr (B, Name_Length, J), |
| Right_Opnd => Make_Integer_Literal (Loc, Uint_0))); |
| end loop; |
| |
| return |
| Make_And_Then (Loc, |
| Left_Opnd => Alist, |
| Right_Opnd => Blist); |
| end Test_Empty_Arrays; |
| |
| ----------------------------- |
| -- Test_Lengths_Correspond -- |
| ----------------------------- |
| |
| function Test_Lengths_Correspond return Node_Id is |
| Result : Node_Id := Empty; |
| |
| begin |
| for J in 1 .. Number_Dimensions (Ltyp) loop |
| Evolve_Or_Else (Result, |
| Make_Op_Ne (Loc, |
| Left_Opnd => Arr_Attr (A, Name_Length, J), |
| Right_Opnd => Arr_Attr (B, Name_Length, J))); |
| end loop; |
| |
| return Result; |
| end Test_Lengths_Correspond; |
| |
| -- Start of processing for Expand_Array_Equality |
| |
| begin |
| Ltyp := Get_Arg_Type (Lhs); |
| Rtyp := Get_Arg_Type (Rhs); |
| |
| -- For now, if the argument types are not the same, go to the base type, |
| -- since the code assumes that the formals have the same type. This is |
| -- fixable in future ??? |
| |
| if Ltyp /= Rtyp then |
| Ltyp := Base_Type (Ltyp); |
| Rtyp := Base_Type (Rtyp); |
| pragma Assert (Ltyp = Rtyp); |
| end if; |
| |
| -- If the array type is distinct from the type of the arguments, it |
| -- is the full view of a private type. Apply an unchecked conversion |
| -- to ensure that analysis of the code below succeeds. |
| |
| if No (Etype (Lhs)) |
| or else Base_Type (Etype (Lhs)) /= Base_Type (Ltyp) |
| then |
| New_Lhs := OK_Convert_To (Ltyp, Lhs); |
| else |
| New_Lhs := Lhs; |
| end if; |
| |
| if No (Etype (Rhs)) |
| or else Base_Type (Etype (Rhs)) /= Base_Type (Rtyp) |
| then |
| New_Rhs := OK_Convert_To (Rtyp, Rhs); |
| else |
| New_Rhs := Rhs; |
| end if; |
| |
| First_Idx := First_Index (Ltyp); |
| |
| -- If optimization is enabled and the array boils down to a couple of |
| -- consecutive elements, generate a simple conjunction of comparisons |
| -- which should be easier to optimize by the code generator. |
| |
| if Optimization_Level > 0 |
| and then Ltyp = Rtyp |
| and then Is_Constrained (Ltyp) |
| and then Number_Dimensions (Ltyp) = 1 |
| and then Compile_Time_Known_Bounds (Ltyp) |
| and then Expr_Value (Type_High_Bound (Etype (First_Idx))) = |
| Expr_Value (Type_Low_Bound (Etype (First_Idx))) + 1 |
| then |
| declare |
| Ctyp : constant Entity_Id := Component_Type (Ltyp); |
| Low_B : constant Node_Id := |
| Type_Low_Bound (Etype (First_Idx)); |
| High_B : constant Node_Id := |
| Type_High_Bound (Etype (First_Idx)); |
| L, R : Node_Id; |
| TestL, TestH : Node_Id; |
| |
| begin |
| L := |
| Make_Indexed_Component (Loc, |
| Prefix => New_Copy_Tree (New_Lhs), |
| Expressions => New_List (New_Copy_Tree (Low_B))); |
| |
| R := |
| Make_Indexed_Component (Loc, |
| Prefix => New_Copy_Tree (New_Rhs), |
| Expressions => New_List (New_Copy_Tree (Low_B))); |
| |
| TestL := Expand_Composite_Equality (Nod, Ctyp, L, R); |
| |
| L := |
| Make_Indexed_Component (Loc, |
| Prefix => New_Lhs, |
| Expressions => New_List (New_Copy_Tree (High_B))); |
| |
| R := |
| Make_Indexed_Component (Loc, |
| Prefix => New_Rhs, |
| Expressions => New_List (New_Copy_Tree (High_B))); |
| |
| TestH := Expand_Composite_Equality (Nod, Ctyp, L, R); |
| |
| return |
| Make_And_Then (Loc, Left_Opnd => TestL, Right_Opnd => TestH); |
| end; |
| end if; |
| |
| -- Build list of formals for function |
| |
| Formals := New_List ( |
| Make_Parameter_Specification (Loc, |
| Defining_Identifier => A, |
| Parameter_Type => New_Occurrence_Of (Ltyp, Loc)), |
| |
| Make_Parameter_Specification (Loc, |
| Defining_Identifier => B, |
| Parameter_Type => New_Occurrence_Of (Rtyp, Loc))); |
| |
| Func_Name := Make_Temporary (Loc, 'E'); |
| |
| -- Build statement sequence for function |
| |
| Func_Body := |
| Make_Subprogram_Body (Loc, |
| Specification => |
| Make_Function_Specification (Loc, |
| Defining_Unit_Name => Func_Name, |
| Parameter_Specifications => Formals, |
| Result_Definition => New_Occurrence_Of (Standard_Boolean, Loc)), |
| |
| Declarations => Decls, |
| |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List ( |
| |
| Make_Implicit_If_Statement (Nod, |
| Condition => Test_Empty_Arrays, |
| Then_Statements => New_List ( |
| Make_Simple_Return_Statement (Loc, |
| Expression => |
| New_Occurrence_Of (Standard_True, Loc)))), |
| |
| Make_Implicit_If_Statement (Nod, |
| Condition => Test_Lengths_Correspond, |
| Then_Statements => New_List ( |
| Make_Simple_Return_Statement (Loc, |
| Expression => New_Occurrence_Of (Standard_False, Loc)))), |
| |
| Handle_One_Dimension (1, First_Idx), |
| |
| Make_Simple_Return_Statement (Loc, |
| Expression => New_Occurrence_Of (Standard_True, Loc))))); |
| |
| Set_Has_Completion (Func_Name, True); |
| Set_Is_Inlined (Func_Name); |
| |
| Append_To (Bodies, Func_Body); |
| |
| return |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Func_Name, Loc), |
| Parameter_Associations => New_List (New_Lhs, New_Rhs)); |
| end Expand_Array_Equality; |
| |
| ----------------------------- |
| -- Expand_Boolean_Operator -- |
| ----------------------------- |
| |
| -- Note that we first get the actual subtypes of the operands, since we |
| -- always want to deal with types that have bounds. |
| |
| procedure Expand_Boolean_Operator (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| |
| begin |
| -- Special case of bit packed array where both operands are known to be |
| -- properly aligned. In this case we use an efficient run time routine |
| -- to carry out the operation (see System.Bit_Ops). |
| |
| if Is_Bit_Packed_Array (Typ) |
| and then not Is_Possibly_Unaligned_Object (Left_Opnd (N)) |
| and then not Is_Possibly_Unaligned_Object (Right_Opnd (N)) |
| then |
| Expand_Packed_Boolean_Operator (N); |
| return; |
| end if; |
| |
| -- For the normal non-packed case, the general expansion is to build |
| -- function for carrying out the comparison (use Make_Boolean_Array_Op) |
| -- and then inserting it into the tree. The original operator node is |
| -- then rewritten as a call to this function. We also use this in the |
| -- packed case if either operand is a possibly unaligned object. |
| |
| declare |
| Loc : constant Source_Ptr := Sloc (N); |
| L : constant Node_Id := Relocate_Node (Left_Opnd (N)); |
| R : Node_Id := Relocate_Node (Right_Opnd (N)); |
| Func_Body : Node_Id; |
| Func_Name : Entity_Id; |
| |
| begin |
| Convert_To_Actual_Subtype (L); |
| Convert_To_Actual_Subtype (R); |
| Ensure_Defined (Etype (L), N); |
| Ensure_Defined (Etype (R), N); |
| Apply_Length_Check (R, Etype (L)); |
| |
| if Nkind (N) = N_Op_Xor then |
| R := Duplicate_Subexpr (R); |
| Silly_Boolean_Array_Xor_Test (N, R, Etype (L)); |
| end if; |
| |
| if Nkind (Parent (N)) = N_Assignment_Statement |
| and then Safe_In_Place_Array_Op (Name (Parent (N)), L, R) |
| then |
| Build_Boolean_Array_Proc_Call (Parent (N), L, R); |
| |
| elsif Nkind (Parent (N)) = N_Op_Not |
| and then Nkind (N) = N_Op_And |
| and then Nkind (Parent (Parent (N))) = N_Assignment_Statement |
| and then Safe_In_Place_Array_Op (Name (Parent (Parent (N))), L, R) |
| then |
| return; |
| else |
| Func_Body := Make_Boolean_Array_Op (Etype (L), N); |
| Func_Name := Defining_Unit_Name (Specification (Func_Body)); |
| Insert_Action (N, Func_Body); |
| |
| -- Now rewrite the expression with a call |
| |
| if Transform_Function_Array then |
| declare |
| Temp_Id : constant Entity_Id := Make_Temporary (Loc, 'T'); |
| Call : Node_Id; |
| Decl : Node_Id; |
| |
| begin |
| -- Generate: |
| -- Temp : ...; |
| |
| Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp_Id, |
| Object_Definition => |
| New_Occurrence_Of (Etype (L), Loc)); |
| |
| -- Generate: |
| -- Proc_Call (L, R, Temp); |
| |
| Call := |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (Func_Name, Loc), |
| Parameter_Associations => |
| New_List ( |
| L, |
| Make_Type_Conversion |
| (Loc, New_Occurrence_Of (Etype (L), Loc), R), |
| New_Occurrence_Of (Temp_Id, Loc))); |
| |
| Insert_Actions (Parent (N), New_List (Decl, Call)); |
| Rewrite (N, New_Occurrence_Of (Temp_Id, Loc)); |
| end; |
| else |
| Rewrite (N, |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Func_Name, Loc), |
| Parameter_Associations => |
| New_List ( |
| L, |
| Make_Type_Conversion |
| (Loc, New_Occurrence_Of (Etype (L), Loc), R)))); |
| end if; |
| |
| Analyze_And_Resolve (N, Typ); |
| end if; |
| end; |
| end Expand_Boolean_Operator; |
| |
| ------------------------------------------------ |
| -- Expand_Compare_Minimize_Eliminate_Overflow -- |
| ------------------------------------------------ |
| |
| procedure Expand_Compare_Minimize_Eliminate_Overflow (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| |
| Result_Type : constant Entity_Id := Etype (N); |
| -- Capture result type (could be a derived boolean type) |
| |
| Llo, Lhi : Uint; |
| Rlo, Rhi : Uint; |
| |
| LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); |
| -- Entity for Long_Long_Integer'Base |
| |
| procedure Set_True; |
| procedure Set_False; |
| -- These procedures rewrite N with an occurrence of Standard_True or |
| -- Standard_False, and then makes a call to Warn_On_Known_Condition. |
| |
| --------------- |
| -- Set_False -- |
| --------------- |
| |
| procedure Set_False is |
| begin |
| Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); |
| Warn_On_Known_Condition (N); |
| end Set_False; |
| |
| -------------- |
| -- Set_True -- |
| -------------- |
| |
| procedure Set_True is |
| begin |
| Rewrite (N, New_Occurrence_Of (Standard_True, Loc)); |
| Warn_On_Known_Condition (N); |
| end Set_True; |
| |
| -- Start of processing for Expand_Compare_Minimize_Eliminate_Overflow |
| |
| begin |
| -- OK, this is the case we are interested in. First step is to process |
| -- our operands using the Minimize_Eliminate circuitry which applies |
| -- this processing to the two operand subtrees. |
| |
| Minimize_Eliminate_Overflows |
| (Left_Opnd (N), Llo, Lhi, Top_Level => False); |
| Minimize_Eliminate_Overflows |
| (Right_Opnd (N), Rlo, Rhi, Top_Level => False); |
| |
| -- See if the range information decides the result of the comparison. |
| -- We can only do this if we in fact have full range information (which |
| -- won't be the case if either operand is bignum at this stage). |
| |
| if Present (Llo) and then Present (Rlo) then |
| case N_Op_Compare (Nkind (N)) is |
| when N_Op_Eq => |
| if Llo = Lhi and then Rlo = Rhi and then Llo = Rlo then |
| Set_True; |
| elsif Llo > Rhi or else Lhi < Rlo then |
| Set_False; |
| end if; |
| |
| when N_Op_Ge => |
| if Llo >= Rhi then |
| Set_True; |
| elsif Lhi < Rlo then |
| Set_False; |
| end if; |
| |
| when N_Op_Gt => |
| if Llo > Rhi then |
| Set_True; |
| elsif Lhi <= Rlo then |
| Set_False; |
| end if; |
| |
| when N_Op_Le => |
| if Llo > Rhi then |
| Set_False; |
| elsif Lhi <= Rlo then |
| Set_True; |
| end if; |
| |
| when N_Op_Lt => |
| if Llo >= Rhi then |
| Set_False; |
| elsif Lhi < Rlo then |
| Set_True; |
| end if; |
| |
| when N_Op_Ne => |
| if Llo = Lhi and then Rlo = Rhi and then Llo = Rlo then |
| Set_False; |
| elsif Llo > Rhi or else Lhi < Rlo then |
| Set_True; |
| end if; |
| end case; |
| |
| -- All done if we did the rewrite |
| |
| if Nkind (N) not in N_Op_Compare then |
| return; |
| end if; |
| end if; |
| |
| -- Otherwise, time to do the comparison |
| |
| declare |
| Ltype : constant Entity_Id := Etype (Left_Opnd (N)); |
| Rtype : constant Entity_Id := Etype (Right_Opnd (N)); |
| |
| begin |
| -- If the two operands have the same signed integer type we are |
| -- all set, nothing more to do. This is the case where either |
| -- both operands were unchanged, or we rewrote both of them to |
| -- be Long_Long_Integer. |
| |
| -- Note: Entity for the comparison may be wrong, but it's not worth |
| -- the effort to change it, since the back end does not use it. |
| |
| if Is_Signed_Integer_Type (Ltype) |
| and then Base_Type (Ltype) = Base_Type (Rtype) |
| then |
| return; |
| |
| -- Here if bignums are involved (can only happen in ELIMINATED mode) |
| |
| elsif Is_RTE (Ltype, RE_Bignum) or else Is_RTE (Rtype, RE_Bignum) then |
| declare |
| Left : Node_Id := Left_Opnd (N); |
| Right : Node_Id := Right_Opnd (N); |
| -- Bignum references for left and right operands |
| |
| begin |
| if not Is_RTE (Ltype, RE_Bignum) then |
| Left := Convert_To_Bignum (Left); |
| elsif not Is_RTE (Rtype, RE_Bignum) then |
| Right := Convert_To_Bignum (Right); |
| end if; |
| |
| -- We rewrite our node with: |
| |
| -- do |
| -- Bnn : Result_Type; |
| -- declare |
| -- M : Mark_Id := SS_Mark; |
| -- begin |
| -- Bnn := Big_xx (Left, Right); (xx = EQ, NT etc) |
| -- SS_Release (M); |
| -- end; |
| -- in |
| -- Bnn |
| -- end |
| |
| declare |
| Blk : constant Node_Id := Make_Bignum_Block (Loc); |
| Bnn : constant Entity_Id := Make_Temporary (Loc, 'B', N); |
| Ent : RE_Id; |
| |
| begin |
| case N_Op_Compare (Nkind (N)) is |
| when N_Op_Eq => Ent := RE_Big_EQ; |
| when N_Op_Ge => Ent := RE_Big_GE; |
| when N_Op_Gt => Ent := RE_Big_GT; |
| when N_Op_Le => Ent := RE_Big_LE; |
| when N_Op_Lt => Ent := RE_Big_LT; |
| when N_Op_Ne => Ent := RE_Big_NE; |
| end case; |
| |
| -- Insert assignment to Bnn into the bignum block |
| |
| Insert_Before |
| (First (Statements (Handled_Statement_Sequence (Blk))), |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Bnn, Loc), |
| Expression => |
| Make_Function_Call (Loc, |
| Name => |
| New_Occurrence_Of (RTE (Ent), Loc), |
| Parameter_Associations => New_List (Left, Right)))); |
| |
| -- Now do the rewrite with expression actions |
| |
| Rewrite (N, |
| Make_Expression_With_Actions (Loc, |
| Actions => New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Bnn, |
| Object_Definition => |
| New_Occurrence_Of (Result_Type, Loc)), |
| Blk), |
| Expression => New_Occurrence_Of (Bnn, Loc))); |
| Analyze_And_Resolve (N, Result_Type); |
| end; |
| end; |
| |
| -- No bignums involved, but types are different, so we must have |
| -- rewritten one of the operands as a Long_Long_Integer but not |
| -- the other one. |
| |
| -- If left operand is Long_Long_Integer, convert right operand |
| -- and we are done (with a comparison of two Long_Long_Integers). |
| |
| elsif Ltype = LLIB then |
| Convert_To_And_Rewrite (LLIB, Right_Opnd (N)); |
| Analyze_And_Resolve (Right_Opnd (N), LLIB, Suppress => All_Checks); |
| return; |
| |
| -- If right operand is Long_Long_Integer, convert left operand |
| -- and we are done (with a comparison of two Long_Long_Integers). |
| |
| -- This is the only remaining possibility |
| |
| else pragma Assert (Rtype = LLIB); |
| Convert_To_And_Rewrite (LLIB, Left_Opnd (N)); |
| Analyze_And_Resolve (Left_Opnd (N), LLIB, Suppress => All_Checks); |
| return; |
| end if; |
| end; |
| end Expand_Compare_Minimize_Eliminate_Overflow; |
| |
| ------------------------------- |
| -- Expand_Composite_Equality -- |
| ------------------------------- |
| |
| -- This function is only called for comparing internal fields of composite |
| -- types when these fields are themselves composites. This is a special |
| -- case because it is not possible to respect normal Ada visibility rules. |
| |
| function Expand_Composite_Equality |
| (Nod : Node_Id; |
| Typ : Entity_Id; |
| Lhs : Node_Id; |
| Rhs : Node_Id) return Node_Id |
| is |
| Loc : constant Source_Ptr := Sloc (Nod); |
| Full_Type : Entity_Id; |
| Eq_Op : Entity_Id; |
| |
| begin |
| if Is_Private_Type (Typ) then |
| Full_Type := Underlying_Type (Typ); |
| else |
| Full_Type := Typ; |
| end if; |
| |
| -- If the private type has no completion the context may be the |
| -- expansion of a composite equality for a composite type with some |
| -- still incomplete components. The expression will not be analyzed |
| -- until the enclosing type is completed, at which point this will be |
| -- properly expanded, unless there is a bona fide completion error. |
| |
| if No (Full_Type) then |
| return Make_Op_Eq (Loc, Left_Opnd => Lhs, Right_Opnd => Rhs); |
| end if; |
| |
| Full_Type := Base_Type (Full_Type); |
| |
| -- When the base type itself is private, use the full view to expand |
| -- the composite equality. |
| |
| if Is_Private_Type (Full_Type) then |
| Full_Type := Underlying_Type (Full_Type); |
| end if; |
| |
| -- Case of tagged record types |
| |
| if Is_Tagged_Type (Full_Type) then |
| Eq_Op := Find_Primitive_Eq (Typ); |
| pragma Assert (Present (Eq_Op)); |
| |
| return |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Eq_Op, Loc), |
| Parameter_Associations => |
| New_List |
| (Unchecked_Convert_To (Etype (First_Formal (Eq_Op)), Lhs), |
| Unchecked_Convert_To (Etype (First_Formal (Eq_Op)), Rhs))); |
| |
| -- Case of untagged record types |
| |
| elsif Is_Record_Type (Full_Type) then |
| Eq_Op := TSS (Full_Type, TSS_Composite_Equality); |
| |
| if Present (Eq_Op) then |
| if Etype (First_Formal (Eq_Op)) /= Full_Type then |
| |
| -- Inherited equality from parent type. Convert the actuals to |
| -- match signature of operation. |
| |
| declare |
| T : constant Entity_Id := Etype (First_Formal (Eq_Op)); |
| |
| begin |
| return |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Eq_Op, Loc), |
| Parameter_Associations => New_List ( |
| OK_Convert_To (T, Lhs), |
| OK_Convert_To (T, Rhs))); |
| end; |
| |
| else |
| -- Comparison between Unchecked_Union components |
| |
| if Is_Unchecked_Union (Full_Type) then |
| declare |
| Lhs_Type : Node_Id := Full_Type; |
| Rhs_Type : Node_Id := Full_Type; |
| Lhs_Discr_Val : Node_Id; |
| Rhs_Discr_Val : Node_Id; |
| |
| begin |
| -- Lhs subtype |
| |
| if Nkind (Lhs) = N_Selected_Component then |
| Lhs_Type := Etype (Entity (Selector_Name (Lhs))); |
| end if; |
| |
| -- Rhs subtype |
| |
| if Nkind (Rhs) = N_Selected_Component then |
| Rhs_Type := Etype (Entity (Selector_Name (Rhs))); |
| end if; |
| |
| -- Lhs of the composite equality |
| |
| if Is_Constrained (Lhs_Type) then |
| |
| -- Since the enclosing record type can never be an |
| -- Unchecked_Union (this code is executed for records |
| -- that do not have variants), we may reference its |
| -- discriminant(s). |
| |
| if Nkind (Lhs) = N_Selected_Component |
| and then Has_Per_Object_Constraint |
| (Entity (Selector_Name (Lhs))) |
| then |
| Lhs_Discr_Val := |
| Make_Selected_Component (Loc, |
| Prefix => Prefix (Lhs), |
| Selector_Name => |
| New_Copy |
| (Get_Discriminant_Value |
| (First_Discriminant (Lhs_Type), |
| Lhs_Type, |
| Stored_Constraint (Lhs_Type)))); |
| |
| else |
| Lhs_Discr_Val := |
| New_Copy |
| (Get_Discriminant_Value |
| (First_Discriminant (Lhs_Type), |
| Lhs_Type, |
| Stored_Constraint (Lhs_Type))); |
| |
| end if; |
| else |
| -- It is not possible to infer the discriminant since |
| -- the subtype is not constrained. |
| |
| return |
| Make_Raise_Program_Error (Loc, |
| Reason => PE_Unchecked_Union_Restriction); |
| end if; |
| |
| -- Rhs of the composite equality |
| |
| if Is_Constrained (Rhs_Type) then |
| if Nkind (Rhs) = N_Selected_Component |
| and then Has_Per_Object_Constraint |
| (Entity (Selector_Name (Rhs))) |
| then |
| Rhs_Discr_Val := |
| Make_Selected_Component (Loc, |
| Prefix => Prefix (Rhs), |
| Selector_Name => |
| New_Copy |
| (Get_Discriminant_Value |
| (First_Discriminant (Rhs_Type), |
| Rhs_Type, |
| Stored_Constraint (Rhs_Type)))); |
| |
| else |
| Rhs_Discr_Val := |
| New_Copy |
| (Get_Discriminant_Value |
| (First_Discriminant (Rhs_Type), |
| Rhs_Type, |
| Stored_Constraint (Rhs_Type))); |
| |
| end if; |
| else |
| return |
| Make_Raise_Program_Error (Loc, |
| Reason => PE_Unchecked_Union_Restriction); |
| end if; |
| |
| -- Call the TSS equality function with the inferred |
| -- discriminant values. |
| |
| return |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Eq_Op, Loc), |
| Parameter_Associations => New_List ( |
| Lhs, |
| Rhs, |
| Lhs_Discr_Val, |
| Rhs_Discr_Val)); |
| end; |
| |
| -- All cases other than comparing Unchecked_Union types |
| |
| else |
| declare |
| T : constant Entity_Id := Etype (First_Formal (Eq_Op)); |
| begin |
| return |
| Make_Function_Call (Loc, |
| Name => |
| New_Occurrence_Of (Eq_Op, Loc), |
| Parameter_Associations => New_List ( |
| OK_Convert_To (T, Lhs), |
| OK_Convert_To (T, Rhs))); |
| end; |
| end if; |
| end if; |
| |
| -- Equality composes in Ada 2012 for untagged record types. It also |
| -- composes for bounded strings, because they are part of the |
| -- predefined environment. We could make it compose for bounded |
| -- strings by making them tagged, or by making sure all subcomponents |
| -- are set to the same value, even when not used. Instead, we have |
| -- this special case in the compiler, because it's more efficient. |
| |
| elsif Ada_Version >= Ada_2012 or else Is_Bounded_String (Typ) then |
| |
| -- If no TSS has been created for the type, check whether there is |
| -- a primitive equality declared for it. |
| |
| declare |
| Op : constant Node_Id := Build_Eq_Call (Typ, Loc, Lhs, Rhs); |
| |
| begin |
| -- Use user-defined primitive if it exists, otherwise use |
| -- predefined equality. |
| |
| if Present (Op) then |
| return Op; |
| else |
| return Make_Op_Eq (Loc, Lhs, Rhs); |
| end if; |
| end; |
| |
| else |
| return Expand_Record_Equality (Nod, Full_Type, Lhs, Rhs); |
| end if; |
| |
| -- Case of non-record types (always use predefined equality) |
| |
| else |
| return Make_Op_Eq (Loc, Left_Opnd => Lhs, Right_Opnd => Rhs); |
| end if; |
| end Expand_Composite_Equality; |
| |
| ------------------------ |
| -- Expand_Concatenate -- |
| ------------------------ |
| |
| procedure Expand_Concatenate (Cnode : Node_Id; Opnds : List_Id) is |
| Loc : constant Source_Ptr := Sloc (Cnode); |
| |
| Atyp : constant Entity_Id := Base_Type (Etype (Cnode)); |
| -- Result type of concatenation |
| |
| Ctyp : constant Entity_Id := Base_Type (Component_Type (Etype (Cnode))); |
| -- Component type. Elements of this component type can appear as one |
| -- of the operands of concatenation as well as arrays. |
| |
| Istyp : constant Entity_Id := Etype (First_Index (Atyp)); |
| -- Index subtype |
| |
| Ityp : constant Entity_Id := Base_Type (Istyp); |
| -- Index type. This is the base type of the index subtype, and is used |
| -- for all computed bounds (which may be out of range of Istyp in the |
| -- case of null ranges). |
| |
| Artyp : Entity_Id; |
| -- This is the type we use to do arithmetic to compute the bounds and |
| -- lengths of operands. The choice of this type is a little subtle and |
| -- is discussed in a separate section at the start of the body code. |
| |
| Result_May_Be_Null : Boolean := True; |
| -- Reset to False if at least one operand is encountered which is known |
| -- at compile time to be non-null. Used for handling the special case |
| -- of setting the high bound to the last operand high bound for a null |
| -- result, thus ensuring a proper high bound in the super-flat case. |
| |
| N : constant Nat := List_Length (Opnds); |
| -- Number of concatenation operands including possibly null operands |
| |
| NN : Nat := 0; |
| -- Number of operands excluding any known to be null, except that the |
| -- last operand is always retained, in case it provides the bounds for |
| -- a null result. |
| |
| Opnd : Node_Id := Empty; |
| -- Current operand being processed in the loop through operands. After |
| -- this loop is complete, always contains the last operand (which is not |
| -- the same as Operands (NN), since null operands are skipped). |
| |
| -- Arrays describing the operands, only the first NN entries of each |
| -- array are set (NN < N when we exclude known null operands). |
| |
| Is_Fixed_Length : array (1 .. N) of Boolean; |
| -- True if length of corresponding operand known at compile time |
| |
| Operands : array (1 .. N) of Node_Id; |
| -- Set to the corresponding entry in the Opnds list (but note that null |
| -- operands are excluded, so not all entries in the list are stored). |
| |
| Fixed_Length : array (1 .. N) of Unat; |
| -- Set to length of operand. Entries in this array are set only if the |
| -- corresponding entry in Is_Fixed_Length is True. |
| |
| Max_Length : array (1 .. N) of Unat; |
| -- Set to the maximum length of operand, or Too_Large_Length_For_Array |
| -- if it is not known. Entries in this array are set only if the |
| -- corresponding entry in Is_Fixed_Length is False; |
| |
| Opnd_Low_Bound : array (1 .. N) of Node_Id; |
| -- Set to lower bound of operand. Either an integer literal in the case |
| -- where the bound is known at compile time, else actual lower bound. |
| -- The operand low bound is of type Ityp. |
| |
| Var_Length : array (1 .. N) of Entity_Id; |
| -- Set to an entity of type Natural that contains the length of an |
| -- operand whose length is not known at compile time. Entries in this |
| -- array are set only if the corresponding entry in Is_Fixed_Length |
| -- is False. The entity is of type Artyp. |
| |
| Aggr_Length : array (0 .. N) of Node_Id; |
| -- The J'th entry is an expression node that represents the total length |
| -- of operands 1 through J. It is either an integer literal node, or a |
| -- reference to a constant entity with the right value, so it is fine |
| -- to just do a Copy_Node to get an appropriate copy. The extra zeroth |
| -- entry always is set to zero. The length is of type Artyp. |
| |
| Max_Aggr_Length : Unat := Too_Large_Length_For_Array; |
| -- Set to the maximum total length, or Too_Large_Length_For_Array at |
| -- least if it is not known. |
| |
| Low_Bound : Node_Id := Empty; |
| -- A tree node representing the low bound of the result (of type Ityp). |
| -- This is either an integer literal node, or an identifier reference to |
| -- a constant entity initialized to the appropriate value. |
| |
| High_Bound : Node_Id := Empty; |
| -- A tree node representing the high bound of the result (of type Ityp) |
| |
| Last_Opnd_Low_Bound : Node_Id := Empty; |
| -- A tree node representing the low bound of the last operand. This |
| -- need only be set if the result could be null. It is used for the |
| -- special case of setting the right low bound for a null result. |
| -- This is of type Ityp. |
| |
| Last_Opnd_High_Bound : Node_Id := Empty; |
| -- A tree node representing the high bound of the last operand. This |
| -- need only be set if the result could be null. It is used for the |
| -- special case of setting the right high bound for a null result. |
| -- This is of type Ityp. |
| |
| Result : Node_Id := Empty; |
| -- Result of the concatenation (of type Ityp) |
| |
| Actions : constant List_Id := New_List; |
| -- Collect actions to be inserted |
| |
| Known_Non_Null_Operand_Seen : Boolean; |
| -- Set True during generation of the assignments of operands into |
| -- result once an operand known to be non-null has been seen. |
| |
| function Library_Level_Target return Boolean; |
| -- Return True if the concatenation is within the expression of the |
| -- declaration of a library-level object. |
| |
| function Make_Artyp_Literal (Val : Uint) return Node_Id; |
| -- This function makes an N_Integer_Literal node that is returned in |
| -- analyzed form with the type set to Artyp. Importantly this literal |
| -- is not flagged as static, so that if we do computations with it that |
| -- result in statically detected out of range conditions, we will not |
| -- generate error messages but instead warning messages. |
| |
| function To_Artyp (X : Node_Id) return Node_Id; |
| -- Given a node of type Ityp, returns the corresponding value of type |
| -- Artyp. For non-enumeration types, this is a plain integer conversion. |
| -- For enum types, the Pos of the value is returned. |
| |
| function To_Ityp (X : Node_Id) return Node_Id; |
| -- The inverse function (uses Val in the case of enumeration types) |
| |
| -------------------------- |
| -- Library_Level_Target -- |
| -------------------------- |
| |
| function Library_Level_Target return Boolean is |
| P : Node_Id := Parent (Cnode); |
| |
| begin |
| while Present (P) loop |
| if Nkind (P) = N_Object_Declaration then |
| return Is_Library_Level_Entity (Defining_Identifier (P)); |
| |
| -- Prevent the search from going too far |
| |
| elsif Is_Body_Or_Package_Declaration (P) then |
| return False; |
| end if; |
| |
| P := Parent (P); |
| end loop; |
| |
| return False; |
| end Library_Level_Target; |
| |
| ------------------------ |
| -- Make_Artyp_Literal -- |
| ------------------------ |
| |
| function Make_Artyp_Literal (Val : Uint) return Node_Id is |
| Result : constant Node_Id := Make_Integer_Literal (Loc, Val); |
| begin |
| Set_Etype (Result, Artyp); |
| Set_Analyzed (Result, True); |
| Set_Is_Static_Expression (Result, False); |
| return Result; |
| end Make_Artyp_Literal; |
| |
| -------------- |
| -- To_Artyp -- |
| -------------- |
| |
| function To_Artyp (X : Node_Id) return Node_Id is |
| begin |
| if Ityp = Base_Type (Artyp) then |
| return X; |
| |
| elsif Is_Enumeration_Type (Ityp) then |
| return |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Ityp, Loc), |
| Attribute_Name => Name_Pos, |
| Expressions => New_List (X)); |
| |
| else |
| return Convert_To (Artyp, X); |
| end if; |
| end To_Artyp; |
| |
| ------------- |
| -- To_Ityp -- |
| ------------- |
| |
| function To_Ityp (X : Node_Id) return Node_Id is |
| begin |
| if Is_Enumeration_Type (Ityp) then |
| return |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Ityp, Loc), |
| Attribute_Name => Name_Val, |
| Expressions => New_List (X)); |
| |
| -- Case where we will do a type conversion |
| |
| else |
| if Ityp = Base_Type (Artyp) then |
| return X; |
| else |
| return Convert_To (Ityp, X); |
| end if; |
| end if; |
| end To_Ityp; |
| |
| -- Local Declarations |
| |
| Opnd_Typ : Entity_Id; |
| Slice_Rng : Entity_Id; |
| Subtyp_Ind : Entity_Id; |
| Ent : Entity_Id; |
| Len : Unat; |
| J : Nat; |
| Clen : Node_Id; |
| Set : Boolean; |
| |
| -- Start of processing for Expand_Concatenate |
| |
| begin |
| -- Choose an appropriate computational type |
| |
| -- We will be doing calculations of lengths and bounds in this routine |
| -- and computing one from the other in some cases, e.g. getting the high |
| -- bound by adding the length-1 to the low bound. |
| |
| -- We can't just use the index type, or even its base type for this |
| -- purpose for two reasons. First it might be an enumeration type which |
| -- is not suitable for computations of any kind, and second it may |
| -- simply not have enough range. For example if the index type is |
| -- -128..+127 then lengths can be up to 256, which is out of range of |
| -- the type. |
| |
| -- For enumeration types, we can simply use Standard_Integer, this is |
| -- sufficient since the actual number of enumeration literals cannot |
| -- possibly exceed the range of integer (remember we will be doing the |
| -- arithmetic with POS values, not representation values). |
| |
| if Is_Enumeration_Type (Ityp) then |
| Artyp := Standard_Integer; |
| |
| -- For modular types, we use a 32-bit modular type for types whose size |
| -- is in the range 1-31 bits. For 32-bit unsigned types, we use the |
| -- identity type, and for larger unsigned types we use a 64-bit type. |
| |
| elsif Is_Modular_Integer_Type (Ityp) then |
| if RM_Size (Ityp) < Standard_Integer_Size then |
| Artyp := Standard_Unsigned; |
| elsif RM_Size (Ityp) = Standard_Integer_Size then |
| Artyp := Ityp; |
| else |
| Artyp := Standard_Long_Long_Unsigned; |
| end if; |
| |
| -- Similar treatment for signed types |
| |
| else |
| if RM_Size (Ityp) < Standard_Integer_Size then |
| Artyp := Standard_Integer; |
| elsif RM_Size (Ityp) = Standard_Integer_Size then |
| Artyp := Ityp; |
| else |
| Artyp := Standard_Long_Long_Integer; |
| end if; |
| end if; |
| |
| -- Supply dummy entry at start of length array |
| |
| Aggr_Length (0) := Make_Artyp_Literal (Uint_0); |
| |
| -- Go through operands setting up the above arrays |
| |
| J := 1; |
| while J <= N loop |
| Opnd := Remove_Head (Opnds); |
| Opnd_Typ := Etype (Opnd); |
| |
| -- The parent got messed up when we put the operands in a list, |
| -- so now put back the proper parent for the saved operand, that |
| -- is to say the concatenation node, to make sure that each operand |
| -- is seen as a subexpression, e.g. if actions must be inserted. |
| |
| Set_Parent (Opnd, Cnode); |
| |
| -- Set will be True when we have setup one entry in the array |
| |
| Set := False; |
| |
| -- Singleton element (or character literal) case |
| |
| if Base_Type (Opnd_Typ) = Ctyp then |
| NN := NN + 1; |
| Operands (NN) := Opnd; |
| Is_Fixed_Length (NN) := True; |
| Fixed_Length (NN) := Uint_1; |
| Result_May_Be_Null := False; |
| |
| -- Set low bound of operand (no need to set Last_Opnd_High_Bound |
| -- since we know that the result cannot be null). |
| |
| Opnd_Low_Bound (NN) := |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Istyp, Loc), |
| Attribute_Name => Name_First); |
| |
| Set := True; |
| |
| -- String literal case (can only occur for strings of course) |
| |
| elsif Nkind (Opnd) = N_String_Literal then |
| Len := String_Literal_Length (Opnd_Typ); |
| |
| if Len > 0 then |
| Result_May_Be_Null := False; |
| end if; |
| |
| -- Capture last operand low and high bound if result could be null |
| |
| if J = N and then Result_May_Be_Null then |
| Last_Opnd_Low_Bound := |
| New_Copy_Tree (String_Literal_Low_Bound (Opnd_Typ)); |
| |
| Last_Opnd_High_Bound := |
| Make_Op_Subtract (Loc, |
| Left_Opnd => |
| New_Copy_Tree (String_Literal_Low_Bound (Opnd_Typ)), |
| Right_Opnd => Make_Integer_Literal (Loc, 1)); |
| end if; |
| |
| -- Skip null string literal |
| |
| if J < N and then Len = 0 then |
| goto Continue; |
| end if; |
| |
| NN := NN + 1; |
| Operands (NN) := Opnd; |
| Is_Fixed_Length (NN) := True; |
| |
| -- Set length and bounds |
| |
| Fixed_Length (NN) := Len; |
| |
| Opnd_Low_Bound (NN) := |
| New_Copy_Tree (String_Literal_Low_Bound (Opnd_Typ)); |
| |
| Set := True; |
| |
| -- All other cases |
| |
| else |
| -- Check constrained case with known bounds |
| |
| if Is_Constrained (Opnd_Typ) |
| and then Compile_Time_Known_Bounds (Opnd_Typ) |
| then |
| declare |
| Lo, Hi : Uint; |
| |
| begin |
| -- Fixed length constrained array type with known at compile |
| -- time bounds is last case of fixed length operand. |
| |
| Get_First_Index_Bounds (Opnd_Typ, Lo, Hi); |
| Len := UI_Max (Hi - Lo + 1, Uint_0); |
| |
| if Len > 0 then |
| Result_May_Be_Null := False; |
| end if; |
| |
| -- Capture last operand bounds if result could be null |
| |
| if J = N and then Result_May_Be_Null then |
| Last_Opnd_Low_Bound := |
| To_Ityp (Make_Integer_Literal (Loc, Lo)); |
| |
| Last_Opnd_High_Bound := |
| To_Ityp (Make_Integer_Literal (Loc, Hi)); |
| end if; |
| |
| -- Exclude null length case unless last operand |
| |
| if J < N and then Len = 0 then |
| goto Continue; |
| end if; |
| |
| NN := NN + 1; |
| Operands (NN) := Opnd; |
| Is_Fixed_Length (NN) := True; |
| Fixed_Length (NN) := Len; |
| |
| Opnd_Low_Bound (NN) := |
| To_Ityp (Make_Integer_Literal (Loc, Lo)); |
| Set := True; |
| end; |
| end if; |
| |
| -- All cases where the length is not known at compile time, or the |
| -- special case of an operand which is known to be null but has a |
| -- lower bound other than 1 or is other than a string type. |
| |
| if not Set then |
| NN := NN + 1; |
| |
| -- Capture operand bounds |
| |
| Opnd_Low_Bound (NN) := |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Duplicate_Subexpr (Opnd, Name_Req => True), |
| Attribute_Name => Name_First); |
| |
| -- Capture last operand bounds if result could be null |
| |
| if J = N and Result_May_Be_Null then |
| Last_Opnd_Low_Bound := |
| Convert_To (Ityp, |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Duplicate_Subexpr (Opnd, Name_Req => True), |
| Attribute_Name => Name_First)); |
| |
| Last_Opnd_High_Bound := |
| Convert_To (Ityp, |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Duplicate_Subexpr (Opnd, Name_Req => True), |
| Attribute_Name => Name_Last)); |
| end if; |
| |
| -- Capture length of operand in entity |
| |
| Operands (NN) := Opnd; |
| Is_Fixed_Length (NN) := False; |
| |
| Var_Length (NN) := Make_Temporary (Loc, 'L'); |
| |
| -- If the operand is a slice, try to compute an upper bound for |
| -- its length. |
| |
| if Nkind (Opnd) = N_Slice |
| and then Is_Constrained (Etype (Prefix (Opnd))) |
| and then Compile_Time_Known_Bounds (Etype (Prefix (Opnd))) |
| then |
| declare |
| Lo, Hi : Uint; |
| |
| begin |
| Get_First_Index_Bounds (Etype (Prefix (Opnd)), Lo, Hi); |
| Max_Length (NN) := UI_Max (Hi - Lo + 1, Uint_0); |
| end; |
| |
| else |
| Max_Length (NN) := Too_Large_Length_For_Array; |
| end if; |
| |
| Append_To (Actions, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Var_Length (NN), |
| Constant_Present => True, |
| Object_Definition => New_Occurrence_Of (Artyp, Loc), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Duplicate_Subexpr (Opnd, Name_Req => True), |
| Attribute_Name => Name_Length))); |
| end if; |
| end if; |
| |
| -- Set next entry in aggregate length array |
| |
| -- For first entry, make either integer literal for fixed length |
| -- or a reference to the saved length for variable length. |
| |
| if NN = 1 then |
| if Is_Fixed_Length (1) then |
| Aggr_Length (1) := Make_Integer_Literal (Loc, Fixed_Length (1)); |
| Max_Aggr_Length := Fixed_Length (1); |
| else |
| Aggr_Length (1) := New_Occurrence_Of (Var_Length (1), Loc); |
| Max_Aggr_Length := Max_Length (1); |
| end if; |
| |
| -- If entry is fixed length and only fixed lengths so far, make |
| -- appropriate new integer literal adding new length. |
| |
| elsif Is_Fixed_Length (NN) |
| and then Nkind (Aggr_Length (NN - 1)) = N_Integer_Literal |
| then |
| Aggr_Length (NN) := |
| Make_Integer_Literal (Loc, |
| Intval => Fixed_Length (NN) + Intval (Aggr_Length (NN - 1))); |
| Max_Aggr_Length := Intval (Aggr_Length (NN)); |
| |
| -- All other cases, construct an addition node for the length and |
| -- create an entity initialized to this length. |
| |
| else |
| Ent := Make_Temporary (Loc, 'L'); |
| |
| if Is_Fixed_Length (NN) then |
| Clen := Make_Integer_Literal (Loc, Fixed_Length (NN)); |
| Max_Aggr_Length := Max_Aggr_Length + Fixed_Length (NN); |
| |
| else |
| Clen := New_Occurrence_Of (Var_Length (NN), Loc); |
| Max_Aggr_Length := Max_Aggr_Length + Max_Length (NN); |
| end if; |
| |
| Append_To (Actions, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Ent, |
| Constant_Present => True, |
| Object_Definition => New_Occurrence_Of (Artyp, Loc), |
| Expression => |
| Make_Op_Add (Loc, |
| Left_Opnd => New_Copy_Tree (Aggr_Length (NN - 1)), |
| Right_Opnd => Clen))); |
| |
| Aggr_Length (NN) := Make_Identifier (Loc, Chars => Chars (Ent)); |
| end if; |
| |
| <<Continue>> |
| J := J + 1; |
| end loop; |
| |
| -- If we have only skipped null operands, return the last operand |
| |
| if NN = 0 then |
| Result := Opnd; |
| goto Done; |
| end if; |
| |
| -- If we have only one non-null operand, return it and we are done. |
| -- There is one case in which this cannot be done, and that is when |
| -- the sole operand is of the element type, in which case it must be |
| -- converted to an array, and the easiest way of doing that is to go |
| -- through the normal general circuit. |
| |
| if NN = 1 and then Base_Type (Etype (Operands (1))) /= Ctyp then |
| Result := Operands (1); |
| goto Done; |
| end if; |
| |
| -- Cases where we have a real concatenation |
| |
| -- Next step is to find the low bound for the result array that we |
| -- will allocate. The rules for this are in (RM 4.5.6(5-7)). |
| |
| -- If the ultimate ancestor of the index subtype is a constrained array |
| -- definition, then the lower bound is that of the index subtype as |
| -- specified by (RM 4.5.3(6)). |
| |
| -- The right test here is to go to the root type, and then the ultimate |
| -- ancestor is the first subtype of this root type. |
| |
| if Is_Constrained (First_Subtype (Root_Type (Atyp))) then |
| Low_Bound := |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of (First_Subtype (Root_Type (Atyp)), Loc), |
| Attribute_Name => Name_First); |
| |
| -- If the first operand in the list has known length we know that |
| -- the lower bound of the result is the lower bound of this operand. |
| |
| elsif Is_Fixed_Length (1) then |
| Low_Bound := Opnd_Low_Bound (1); |
| |
| -- OK, we don't know the lower bound, we have to build a horrible |
| -- if expression node of the form |
| |
| -- if Cond1'Length /= 0 then |
| -- Opnd1 low bound |
| -- else |
| -- if Opnd2'Length /= 0 then |
| -- Opnd2 low bound |
| -- else |
| -- ... |
| |
| -- The nesting ends either when we hit an operand whose length is known |
| -- at compile time, or on reaching the last operand, whose low bound we |
| -- take unconditionally whether or not it is null. It's easiest to do |
| -- this with a recursive procedure: |
| |
| else |
| declare |
| function Get_Known_Bound (J : Nat) return Node_Id; |
| -- Returns the lower bound determined by operands J .. NN |
| |
| --------------------- |
| -- Get_Known_Bound -- |
| --------------------- |
| |
| function Get_Known_Bound (J : Nat) return Node_Id is |
| begin |
| if Is_Fixed_Length (J) or else J = NN then |
| return New_Copy_Tree (Opnd_Low_Bound (J)); |
| |
| else |
| return |
| Make_If_Expression (Loc, |
| Expressions => New_List ( |
| |
| Make_Op_Ne (Loc, |
| Left_Opnd => |
| New_Occurrence_Of (Var_Length (J), Loc), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, 0)), |
| |
| New_Copy_Tree (Opnd_Low_Bound (J)), |
| Get_Known_Bound (J + 1))); |
| end if; |
| end Get_Known_Bound; |
| |
| begin |
| Ent := Make_Temporary (Loc, 'L'); |
| |
| Append_To (Actions, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Ent, |
| Constant_Present => True, |
| Object_Definition => New_Occurrence_Of (Ityp, Loc), |
| Expression => Get_Known_Bound (1))); |
| |
| Low_Bound := New_Occurrence_Of (Ent, Loc); |
| end; |
| end if; |
| |
| pragma Assert (Present (Low_Bound)); |
| |
| -- Now we can compute the high bound as Low_Bound + Length - 1 |
| |
| if Compile_Time_Known_Value (Low_Bound) |
| and then Nkind (Aggr_Length (NN)) = N_Integer_Literal |
| then |
| High_Bound := |
| To_Ityp |
| (Make_Artyp_Literal |
| (Expr_Value (Low_Bound) + Intval (Aggr_Length (NN)) - 1)); |
| |
| else |
| High_Bound := |
| To_Ityp |
| (Make_Op_Add (Loc, |
| Left_Opnd => To_Artyp (New_Copy_Tree (Low_Bound)), |
| Right_Opnd => |
| Make_Op_Subtract (Loc, |
| Left_Opnd => New_Copy_Tree (Aggr_Length (NN)), |
| Right_Opnd => Make_Artyp_Literal (Uint_1)))); |
| |
| -- Note that calculation of the high bound may cause overflow in some |
| -- very weird cases, so in the general case we need an overflow check |
| -- on the high bound. We can avoid this for the common case of string |
| -- types and other types whose index is Positive, since we chose a |
| -- wider range for the arithmetic type. If checks are suppressed, we |
| -- do not set the flag so superfluous warnings may be omitted. |
| |
| if Istyp /= Standard_Positive |
| and then not Overflow_Checks_Suppressed (Istyp) |
| then |
| Activate_Overflow_Check (High_Bound); |
| end if; |
| end if; |
| |
| -- Handle the exceptional case where the result is null, in which case |
| -- case the bounds come from the last operand (so that we get the proper |
| -- bounds if the last operand is super-flat). |
| |
| if Result_May_Be_Null then |
| Low_Bound := |
| Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Make_Op_Eq (Loc, |
| Left_Opnd => New_Copy_Tree (Aggr_Length (NN)), |
| Right_Opnd => Make_Artyp_Literal (Uint_0)), |
| Last_Opnd_Low_Bound, |
| Low_Bound)); |
| |
| High_Bound := |
| Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Make_Op_Eq (Loc, |
| Left_Opnd => New_Copy_Tree (Aggr_Length (NN)), |
| Right_Opnd => Make_Artyp_Literal (Uint_0)), |
| Last_Opnd_High_Bound, |
| High_Bound)); |
| end if; |
| |
| -- Here is where we insert the saved up actions |
| |
| Insert_Actions (Cnode, Actions, Suppress => All_Checks); |
| |
| -- If the low bound is known at compile time and not the high bound, but |
| -- we have computed a sensible upper bound for the length, then adjust |
| -- the high bound for the subtype of the array. This will change it into |
| -- a static subtype and thus help the code generator. |
| |
| if Compile_Time_Known_Value (Low_Bound) |
| and then not Compile_Time_Known_Value (High_Bound) |
| and then Max_Aggr_Length < Too_Large_Length_For_Array |
| then |
| declare |
| Known_High_Bound : constant Node_Id := |
| To_Ityp |
| (Make_Artyp_Literal |
| (Expr_Value (Low_Bound) + Max_Aggr_Length - 1)); |
| |
| begin |
| if not Is_Out_Of_Range (Known_High_Bound, Ityp) then |
| Slice_Rng := Make_Range (Loc, Low_Bound, High_Bound); |
| High_Bound := Known_High_Bound; |
| |
| else |
| Slice_Rng := Empty; |
| end if; |
| end; |
| |
| else |
| Slice_Rng := Empty; |
| end if; |
| |
| -- Now we construct an array object with appropriate bounds. We mark |
| -- the target as internal to prevent useless initialization when |
| -- Initialize_Scalars is enabled. Also since this is the actual result |
| -- entity, we make sure we have debug information for the result. |
| |
| Subtyp_Ind := |
| Make_Subtype_Indication (Loc, |
| Subtype_Mark => New_Occurrence_Of (Atyp, Loc), |
| Constraint => |
| Make_Index_Or_Discriminant_Constraint (Loc, |
| Constraints => New_List ( |
| Make_Range (Loc, |
| Low_Bound => Low_Bound, |
| High_Bound => High_Bound)))); |
| |
| Ent := Make_Temporary (Loc, 'S'); |
| Set_Is_Internal (Ent); |
| Set_Debug_Info_Needed (Ent); |
| |
| -- If we are concatenating strings and the current scope already uses |
| -- the secondary stack, allocate the resulting string also on the |
| -- secondary stack to avoid putting too much pressure on the primary |
| -- stack. |
| -- Don't do this if -gnatd.h is set, as this will break the wrapping of |
| -- Cnode in an Expression_With_Actions, see Expand_N_Op_Concat. |
| |
| if Atyp = Standard_String |
| and then Uses_Sec_Stack (Current_Scope) |
| and then RTE_Available (RE_SS_Pool) |
| and then not Debug_Flag_Dot_H |
| then |
| -- Generate: |
| -- subtype Axx is ...; |
| -- type Ayy is access Axx; |
| -- Rxx : Ayy := new <subtype> [storage_pool = ss_pool]; |
| -- Sxx : <subtype> renames Rxx.all; |
| |
| declare |
| Alloc : Node_Id; |
| ConstrT : constant Entity_Id := Make_Temporary (Loc, 'A'); |
| Acc_Typ : constant Entity_Id := Make_Temporary (Loc, 'A'); |
| Temp : Entity_Id; |
| |
| begin |
| Insert_Action (Cnode, |
| Make_Subtype_Declaration (Loc, |
| Defining_Identifier => ConstrT, |
| Subtype_Indication => Subtyp_Ind), |
| Suppress => All_Checks); |
| Freeze_Itype (ConstrT, Cnode); |
| |
| Insert_Action (Cnode, |
| Make_Full_Type_Declaration (Loc, |
| Defining_Identifier => Acc_Typ, |
| Type_Definition => |
| Make_Access_To_Object_Definition (Loc, |
| Subtype_Indication => New_Occurrence_Of (ConstrT, Loc))), |
| Suppress => All_Checks); |
| Alloc := |
| Make_Allocator (Loc, |
| Expression => New_Occurrence_Of (ConstrT, Loc)); |
| |
| -- Allocate on the secondary stack. This is currently done |
| -- only for type String, which normally doesn't have default |
| -- initialization, but we need to Set_No_Initialization in case |
| -- of Initialize_Scalars or Normalize_Scalars; otherwise, the |
| -- allocator will get transformed and will not use the secondary |
| -- stack. |
| |
| Set_Storage_Pool (Alloc, RTE (RE_SS_Pool)); |
| Set_Procedure_To_Call (Alloc, RTE (RE_SS_Allocate)); |
| Set_No_Initialization (Alloc); |
| |
| Temp := Make_Temporary (Loc, 'R', Alloc); |
| Insert_Action (Cnode, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Object_Definition => New_Occurrence_Of (Acc_Typ, Loc), |
| Expression => Alloc), |
| Suppress => All_Checks); |
| |
| Insert_Action (Cnode, |
| Make_Object_Renaming_Declaration (Loc, |
| Defining_Identifier => Ent, |
| Subtype_Mark => New_Occurrence_Of (ConstrT, Loc), |
| Name => |
| Make_Explicit_Dereference (Loc, |
| Prefix => New_Occurrence_Of (Temp, Loc))), |
| Suppress => All_Checks); |
| end; |
| else |
| -- If the bound is statically known to be out of range, we do not |
| -- want to abort, we want a warning and a runtime constraint error. |
| -- Note that we have arranged that the result will not be treated as |
| -- a static constant, so we won't get an illegality during this |
| -- insertion. |
| -- We also enable checks (in particular range checks) in case the |
| -- bounds of Subtyp_Ind are out of range. |
| |
| Insert_Action (Cnode, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Ent, |
| Object_Definition => Subtyp_Ind)); |
| end if; |
| |
| -- If the result of the concatenation appears as the initializing |
| -- expression of an object declaration, we can just rename the |
| -- result, rather than copying it. |
| |
| Set_OK_To_Rename (Ent); |
| |
| -- Catch the static out of range case now |
| |
| if Raises_Constraint_Error (High_Bound) |
| or else Is_Out_Of_Range (High_Bound, Ityp) |
| then |
| -- Kill warning generated for the declaration of the static out of |
| -- range high bound, and instead generate a Constraint_Error with |
| -- an appropriate specific message. |
| |
| if Nkind (High_Bound) = N_Integer_Literal then |
| Kill_Dead_Code (High_Bound); |
| Rewrite (High_Bound, New_Copy_Tree (Low_Bound)); |
| |
| else |
| Kill_Dead_Code (Declaration_Node (Entity (High_Bound))); |
| end if; |
| |
| Apply_Compile_Time_Constraint_Error |
| (N => Cnode, |
| Msg => "concatenation result upper bound out of range??", |
| Reason => CE_Range_Check_Failed); |
| |
| return; |
| end if; |
| |
| -- Now we will generate the assignments to do the actual concatenation |
| |
| -- There is one case in which we will not do this, namely when all the |
| -- following conditions are met: |
| |
| -- The result type is Standard.String |
| |
| -- There are nine or fewer retained (non-null) operands |
| |
| -- The optimization level is -O0 or the debug flag gnatd.C is set, |
| -- and the debug flag gnatd.c is not set. |
| |
| -- The corresponding System.Concat_n.Str_Concat_n routine is |
| -- available in the run time. |
| |
| -- If all these conditions are met then we generate a call to the |
| -- relevant concatenation routine. The purpose of this is to avoid |
| -- undesirable code bloat at -O0. |
| |
| -- If the concatenation is within the declaration of a library-level |
| -- object, we call the built-in concatenation routines to prevent code |
| -- bloat, regardless of the optimization level. This is space efficient |
| -- and prevents linking problems when units are compiled with different |
| -- optimization levels. |
| |
| if Atyp = Standard_String |
| and then NN in 2 .. 9 |
| and then (((Optimization_Level = 0 or else Debug_Flag_Dot_CC) |
| and then not Debug_Flag_Dot_C) |
| or else Library_Level_Target) |
| then |
| declare |
| RR : constant array (Nat range 2 .. 9) of RE_Id := |
| (RE_Str_Concat_2, |
| RE_Str_Concat_3, |
| RE_Str_Concat_4, |
| RE_Str_Concat_5, |
| RE_Str_Concat_6, |
| RE_Str_Concat_7, |
| RE_Str_Concat_8, |
| RE_Str_Concat_9); |
| |
| begin |
| if RTE_Available (RR (NN)) then |
| declare |
| Opnds : constant List_Id := |
| New_List (New_Occurrence_Of (Ent, Loc)); |
| |
| begin |
| for J in 1 .. NN loop |
| if Is_List_Member (Operands (J)) then |
| Remove (Operands (J)); |
| end if; |
| |
| if Base_Type (Etype (Operands (J))) = Ctyp then |
| Append_To (Opnds, |
| Make_Aggregate (Loc, |
| Component_Associations => New_List ( |
| Make_Component_Association (Loc, |
| Choices => New_List ( |
| Make_Integer_Literal (Loc, 1)), |
| Expression => Operands (J))))); |
| |
| else |
| Append_To (Opnds, Operands (J)); |
| end if; |
| end loop; |
| |
| Insert_Action (Cnode, |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (RTE (RR (NN)), Loc), |
| Parameter_Associations => Opnds)); |
| |
| -- No assignments left to do below |
| |
| NN := 0; |
| end; |
| end if; |
| end; |
| end if; |
| |
| -- Not special case so generate the assignments |
| |
| Known_Non_Null_Operand_Seen := False; |
| |
| for J in 1 .. NN loop |
| declare |
| Lo : constant Node_Id := |
| Make_Op_Add (Loc, |
| Left_Opnd => To_Artyp (New_Copy_Tree (Low_Bound)), |
| Right_Opnd => Aggr_Length (J - 1)); |
| |
| Hi : constant Node_Id := |
| Make_Op_Add (Loc, |
| Left_Opnd => To_Artyp (New_Copy_Tree (Low_Bound)), |
| Right_Opnd => |
| Make_Op_Subtract (Loc, |
| Left_Opnd => Aggr_Length (J), |
| Right_Opnd => Make_Artyp_Literal (Uint_1))); |
| |
| begin |
| -- Singleton case, simple assignment |
| |
| if Base_Type (Etype (Operands (J))) = Ctyp then |
| Known_Non_Null_Operand_Seen := True; |
| Insert_Action (Cnode, |
| Make_Assignment_Statement (Loc, |
| Name => |
| Make_Indexed_Component (Loc, |
| Prefix => New_Occurrence_Of (Ent, Loc), |
| Expressions => New_List (To_Ityp (Lo))), |
| Expression => Operands (J)), |
| Suppress => All_Checks); |
| |
| -- Array case, slice assignment, skipped when argument is fixed |
| -- length and known to be null. |
| |
| elsif (not Is_Fixed_Length (J)) or else (Fixed_Length (J) > 0) then |
| declare |
| Assign : Node_Id := |
| Make_Assignment_Statement (Loc, |
| Name => |
| Make_Slice (Loc, |
| Prefix => |
| New_Occurrence_Of (Ent, Loc), |
| Discrete_Range => |
| Make_Range (Loc, |
| Low_Bound => To_Ityp (Lo), |
| High_Bound => To_Ityp (Hi))), |
| Expression => Operands (J)); |
| begin |
| if Is_Fixed_Length (J) then |
| Known_Non_Null_Operand_Seen := True; |
| |
| elsif not Known_Non_Null_Operand_Seen then |
| |
| -- Here if operand length is not statically known and no |
| -- operand known to be non-null has been processed yet. |
| -- If operand length is 0, we do not need to perform the |
| -- assignment, and we must avoid the evaluation of the |
| -- high bound of the slice, since it may underflow if the |
| -- low bound is Ityp'First. |
| |
| Assign := |
| Make_Implicit_If_Statement (Cnode, |
| Condition => |
| Make_Op_Ne (Loc, |
| Left_Opnd => |
| New_Occurrence_Of (Var_Length (J), Loc), |
| Right_Opnd => Make_Integer_Literal (Loc, 0)), |
| Then_Statements => New_List (Assign)); |
| end if; |
| |
| Insert_Action (Cnode, Assign, Suppress => All_Checks); |
| end; |
| end if; |
| end; |
| end loop; |
| |
| -- Finally we build the result, which is either a direct reference to |
| -- the array object or a slice of it. |
| |
| Result := New_Occurrence_Of (Ent, Loc); |
| |
| if Present (Slice_Rng) then |
| Result := Make_Slice (Loc, Result, Slice_Rng); |
| end if; |
| |
| <<Done>> |
| pragma Assert (Present (Result)); |
| Rewrite (Cnode, Result); |
| Analyze_And_Resolve (Cnode, Atyp); |
| end Expand_Concatenate; |
| |
| --------------------------------------------------- |
| -- Expand_Membership_Minimize_Eliminate_Overflow -- |
| --------------------------------------------------- |
| |
| procedure Expand_Membership_Minimize_Eliminate_Overflow (N : Node_Id) is |
| pragma Assert (Nkind (N) = N_In); |
| -- Despite the name, this routine applies only to N_In, not to |
| -- N_Not_In. The latter is always rewritten as not (X in Y). |
| |
| Result_Type : constant Entity_Id := Etype (N); |
| -- Capture result type, may be a derived boolean type |
| |
| Loc : constant Source_Ptr := Sloc (N); |
| Lop : constant Node_Id := Left_Opnd (N); |
| Rop : constant Node_Id := Right_Opnd (N); |
| |
| -- Note: there are many referencs to Etype (Lop) and Etype (Rop). It |
| -- is thus tempting to capture these values, but due to the rewrites |
| -- that occur as a result of overflow checking, these values change |
| -- as we go along, and it is safe just to always use Etype explicitly. |
| |
| Restype : constant Entity_Id := Etype (N); |
| -- Save result type |
| |
| Lo, Hi : Uint; |
| -- Bounds in Minimize calls, not used currently |
| |
| LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); |
| -- Entity for Long_Long_Integer'Base |
| |
| begin |
| Minimize_Eliminate_Overflows (Lop, Lo, Hi, Top_Level => False); |
| |
| -- If right operand is a subtype name, and the subtype name has no |
| -- predicate, then we can just replace the right operand with an |
| -- explicit range T'First .. T'Last, and use the explicit range code. |
| |
| if Nkind (Rop) /= N_Range |
| and then No (Predicate_Function (Etype (Rop))) |
| then |
| declare |
| Rtyp : constant Entity_Id := Etype (Rop); |
| begin |
| Rewrite (Rop, |
| Make_Range (Loc, |
| Low_Bound => |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_First, |
| Prefix => New_Occurrence_Of (Rtyp, Loc)), |
| High_Bound => |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Last, |
| Prefix => New_Occurrence_Of (Rtyp, Loc)))); |
| Analyze_And_Resolve (Rop, Rtyp, Suppress => All_Checks); |
| end; |
| end if; |
| |
| -- Here for the explicit range case. Note that the bounds of the range |
| -- have not been processed for minimized or eliminated checks. |
| |
| if Nkind (Rop) = N_Range then |
| Minimize_Eliminate_Overflows |
| (Low_Bound (Rop), Lo, Hi, Top_Level => False); |
| Minimize_Eliminate_Overflows |
| (High_Bound (Rop), Lo, Hi, Top_Level => False); |
| |
| -- We have A in B .. C, treated as A >= B and then A <= C |
| |
| -- Bignum case |
| |
| if Is_RTE (Etype (Lop), RE_Bignum) |
| or else Is_RTE (Etype (Low_Bound (Rop)), RE_Bignum) |
| or else Is_RTE (Etype (High_Bound (Rop)), RE_Bignum) |
| then |
| declare |
| Blk : constant Node_Id := Make_Bignum_Block (Loc); |
| Bnn : constant Entity_Id := Make_Temporary (Loc, 'B', N); |
| L : constant Entity_Id := |
| Make_Defining_Identifier (Loc, Name_uL); |
| Lopnd : constant Node_Id := Convert_To_Bignum (Lop); |
| Lbound : constant Node_Id := |
| Convert_To_Bignum (Low_Bound (Rop)); |
| Hbound : constant Node_Id := |
| Convert_To_Bignum (High_Bound (Rop)); |
| |
| -- Now we rewrite the membership test node to look like |
| |
| -- do |
| -- Bnn : Result_Type; |
| -- declare |
| -- M : Mark_Id := SS_Mark; |
| -- L : Bignum := Lopnd; |
| -- begin |
| -- Bnn := Big_GE (L, Lbound) and then Big_LE (L, Hbound) |
| -- SS_Release (M); |
| -- end; |
| -- in |
| -- Bnn |
| -- end |
| |
| begin |
| -- Insert declaration of L into declarations of bignum block |
| |
| Insert_After |
| (Last (Declarations (Blk)), |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => L, |
| Object_Definition => |
| New_Occurrence_Of (RTE (RE_Bignum), Loc), |
| Expression => Lopnd)); |
| |
| -- Insert assignment to Bnn into expressions of bignum block |
| |
| Insert_Before |
| (First (Statements (Handled_Statement_Sequence (Blk))), |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Bnn, Loc), |
| Expression => |
| Make_And_Then (Loc, |
| Left_Opnd => |
| Make_Function_Call (Loc, |
| Name => |
| New_Occurrence_Of (RTE (RE_Big_GE), Loc), |
| Parameter_Associations => New_List ( |
| New_Occurrence_Of (L, Loc), |
| Lbound)), |
| |
| Right_Opnd => |
| Make_Function_Call (Loc, |
| Name => |
| New_Occurrence_Of (RTE (RE_Big_LE), Loc), |
| Parameter_Associations => New_List ( |
| New_Occurrence_Of (L, Loc), |
| Hbound))))); |
| |
| -- Now rewrite the node |
| |
| Rewrite (N, |
| Make_Expression_With_Actions (Loc, |
| Actions => New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Bnn, |
| Object_Definition => |
| New_Occurrence_Of (Result_Type, Loc)), |
| Blk), |
| Expression => New_Occurrence_Of (Bnn, Loc))); |
| Analyze_And_Resolve (N, Result_Type); |
| return; |
| end; |
| |
| -- Here if no bignums around |
| |
| else |
| -- Case where types are all the same |
| |
| if Base_Type (Etype (Lop)) = Base_Type (Etype (Low_Bound (Rop))) |
| and then |
| Base_Type (Etype (Lop)) = Base_Type (Etype (High_Bound (Rop))) |
| then |
| null; |
| |
| -- If types are not all the same, it means that we have rewritten |
| -- at least one of them to be of type Long_Long_Integer, and we |
| -- will convert the other operands to Long_Long_Integer. |
| |
| else |
| Convert_To_And_Rewrite (LLIB, Lop); |
| Set_Analyzed (Lop, False); |
| Analyze_And_Resolve (Lop, LLIB); |
| |
| -- For the right operand, avoid unnecessary recursion into |
| -- this routine, we know that overflow is not possible. |
| |
| Convert_To_And_Rewrite (LLIB, Low_Bound (Rop)); |
| Convert_To_And_Rewrite (LLIB, High_Bound (Rop)); |
| Set_Analyzed (Rop, False); |
| Analyze_And_Resolve (Rop, LLIB, Suppress => Overflow_Check); |
| end if; |
| |
| -- Now the three operands are of the same signed integer type, |
| -- so we can use the normal expansion routine for membership, |
| -- setting the flag to prevent recursion into this procedure. |
| |
| Set_No_Minimize_Eliminate (N); |
| Expand_N_In (N); |
| end if; |
| |
| -- Right operand is a subtype name and the subtype has a predicate. We |
| -- have to make sure the predicate is checked, and for that we need to |
| -- use the standard N_In circuitry with appropriate types. |
| |
| else |
| pragma Assert (Present (Predicate_Function (Etype (Rop)))); |
| |
| -- If types are "right", just call Expand_N_In preventing recursion |
| |
| if Base_Type (Etype (Lop)) = Base_Type (Etype (Rop)) then |
| Set_No_Minimize_Eliminate (N); |
| Expand_N_In (N); |
| |
| -- Bignum case |
| |
| elsif Is_RTE (Etype (Lop), RE_Bignum) then |
| |
| -- For X in T, we want to rewrite our node as |
| |
| -- do |
| -- Bnn : Result_Type; |
| |
| -- declare |
| -- M : Mark_Id := SS_Mark; |
| -- Lnn : Long_Long_Integer'Base |
| -- Nnn : Bignum; |
| |
| -- begin |
| -- Nnn := X; |
| |
| -- if not Bignum_In_LLI_Range (Nnn) then |
| -- Bnn := False; |
| -- else |
| -- Lnn := From_Bignum (Nnn); |
| -- Bnn := |
| -- Lnn in LLIB (T'Base'First) .. LLIB (T'Base'Last) |
| -- and then T'Base (Lnn) in T; |
| -- end if; |
| |
| -- SS_Release (M); |
| -- end |
| -- in |
| -- Bnn |
| -- end |
| |
| -- A bit gruesome, but there doesn't seem to be a simpler way |
| |
| declare |
| Blk : constant Node_Id := Make_Bignum_Block (Loc); |
| Bnn : constant Entity_Id := Make_Temporary (Loc, 'B', N); |
| Lnn : constant Entity_Id := Make_Temporary (Loc, 'L', N); |
| Nnn : constant Entity_Id := Make_Temporary (Loc, 'N', N); |
| T : constant Entity_Id := Etype (Rop); |
| TB : constant Entity_Id := Base_Type (T); |
| Nin : Node_Id; |
| |
| begin |
| -- Mark the last membership operation to prevent recursion |
| |
| Nin := |
| Make_In (Loc, |
| Left_Opnd => Convert_To (TB, New_Occurrence_Of (Lnn, Loc)), |
| Right_Opnd => New_Occurrence_Of (T, Loc)); |
| Set_No_Minimize_Eliminate (Nin); |
| |
| -- Now decorate the block |
| |
| Insert_After |
| (Last (Declarations (Blk)), |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Lnn, |
| Object_Definition => New_Occurrence_Of (LLIB, Loc))); |
| |
| Insert_After |
| (Last (Declarations (Blk)), |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Nnn, |
| Object_Definition => |
| New_Occurrence_Of (RTE (RE_Bignum), Loc))); |
| |
| Insert_List_Before |
| (First (Statements (Handled_Statement_Sequence (Blk))), |
| New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Nnn, Loc), |
| Expression => Relocate_Node (Lop)), |
| |
| Make_Implicit_If_Statement (N, |
| Condition => |
| Make_Op_Not (Loc, |
| Right_Opnd => |
| Make_Function_Call (Loc, |
| Name => |
| New_Occurrence_Of |
| (RTE (RE_Bignum_In_LLI_Range), Loc), |
| Parameter_Associations => New_List ( |
| New_Occurrence_Of (Nnn, Loc)))), |
| |
| Then_Statements => New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Bnn, Loc), |
| Expression => |
| New_Occurrence_Of (Standard_False, Loc))), |
| |
| Else_Statements => New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Lnn, Loc), |
| Expression => |
| Make_Function_Call (Loc, |
| Name => |
| New_Occurrence_Of (RTE (RE_From_Bignum), Loc), |
| Parameter_Associations => New_List ( |
| New_Occurrence_Of (Nnn, Loc)))), |
| |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Bnn, Loc), |
| Expression => |
| Make_And_Then (Loc, |
| Left_Opnd => |
| Make_In (Loc, |
| Left_Opnd => New_Occurrence_Of (Lnn, Loc), |
| Right_Opnd => |
| Make_Range (Loc, |
| Low_Bound => |
| Convert_To (LLIB, |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_First, |
| Prefix => |
| New_Occurrence_Of (TB, Loc))), |
| |
| High_Bound => |
| Convert_To (LLIB, |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Last, |
| Prefix => |
| New_Occurrence_Of (TB, Loc))))), |
| |
| Right_Opnd => Nin)))))); |
| |
| -- Now we can do the rewrite |
| |
| Rewrite (N, |
| Make_Expression_With_Actions (Loc, |
| Actions => New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Bnn, |
| Object_Definition => |
| New_Occurrence_Of (Result_Type, Loc)), |
| Blk), |
| Expression => New_Occurrence_Of (Bnn, Loc))); |
| Analyze_And_Resolve (N, Result_Type); |
| return; |
| end; |
| |
| -- Not bignum case, but types don't match (this means we rewrote the |
| -- left operand to be Long_Long_Integer). |
| |
| else |
| pragma Assert (Base_Type (Etype (Lop)) = LLIB); |
| |
| -- We rewrite the membership test as (where T is the type with |
| -- the predicate, i.e. the type of the right operand) |
| |
| -- Lop in LLIB (T'Base'First) .. LLIB (T'Base'Last) |
| -- and then T'Base (Lop) in T |
| |
| declare |
| T : constant Entity_Id := Etype (Rop); |
| TB : constant Entity_Id := Base_Type (T); |
| Nin : Node_Id; |
| |
| begin |
| -- The last membership test is marked to prevent recursion |
| |
| Nin := |
| Make_In (Loc, |
| Left_Opnd => Convert_To (TB, Duplicate_Subexpr (Lop)), |
| Right_Opnd => New_Occurrence_Of (T, Loc)); |
| Set_No_Minimize_Eliminate (Nin); |
| |
| -- Now do the rewrite |
| |
| Rewrite (N, |
| Make_And_Then (Loc, |
| Left_Opnd => |
| Make_In (Loc, |
| Left_Opnd => Lop, |
| Right_Opnd => |
| Make_Range (Loc, |
| Low_Bound => |
| Convert_To (LLIB, |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_First, |
| Prefix => |
| New_Occurrence_Of (TB, Loc))), |
| High_Bound => |
| Convert_To (LLIB, |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Last, |
| Prefix => |
| New_Occurrence_Of (TB, Loc))))), |
| Right_Opnd => Nin)); |
| Set_Analyzed (N, False); |
| Analyze_And_Resolve (N, Restype); |
| end; |
| end if; |
| end if; |
| end Expand_Membership_Minimize_Eliminate_Overflow; |
| |
| --------------------------------- |
| -- Expand_Nonbinary_Modular_Op -- |
| --------------------------------- |
| |
| procedure Expand_Nonbinary_Modular_Op (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| |
| procedure Expand_Modular_Addition; |
| -- Expand the modular addition, handling the special case of adding a |
| -- constant. |
| |
| procedure Expand_Modular_Op; |
| -- Compute the general rule: (lhs OP rhs) mod Modulus |
| |
| procedure Expand_Modular_Subtraction; |
| -- Expand the modular addition, handling the special case of subtracting |
| -- a constant. |
| |
| ----------------------------- |
| -- Expand_Modular_Addition -- |
| ----------------------------- |
| |
| procedure Expand_Modular_Addition is |
| begin |
| -- If this is not the addition of a constant then compute it using |
| -- the general rule: (lhs + rhs) mod Modulus |
| |
| if Nkind (Right_Opnd (N)) /= N_Integer_Literal then |
| Expand_Modular_Op; |
| |
| -- If this is an addition of a constant, convert it to a subtraction |
| -- plus a conditional expression since we can compute it faster than |
| -- computing the modulus. |
| |
| -- modMinusRhs = Modulus - rhs |
| -- if lhs < modMinusRhs then lhs + rhs |
| -- else lhs - modMinusRhs |
| |
| else |
| declare |
| Mod_Minus_Right : constant Uint := |
| Modulus (Typ) - Intval (Right_Opnd (N)); |
| |
| Exprs : constant List_Id := New_List; |
| Cond_Expr : constant Node_Id := New_Op_Node (N_Op_Lt, Loc); |
| Then_Expr : constant Node_Id := New_Op_Node (N_Op_Add, Loc); |
| Else_Expr : constant Node_Id := New_Op_Node (N_Op_Subtract, |
| Loc); |
| begin |
| -- To prevent spurious visibility issues, convert all |
| -- operands to Standard.Unsigned. |
| |
| Set_Left_Opnd (Cond_Expr, |
| Unchecked_Convert_To (Standard_Unsigned, |
| New_Copy_Tree (Left_Opnd (N)))); |
| Set_Right_Opnd (Cond_Expr, |
| Make_Integer_Literal (Loc, Mod_Minus_Right)); |
| Append_To (Exprs, Cond_Expr); |
| |
| Set_Left_Opnd (Then_Expr, |
| Unchecked_Convert_To (Standard_Unsigned, |
| New_Copy_Tree (Left_Opnd (N)))); |
| Set_Right_Opnd (Then_Expr, |
| Make_Integer_Literal (Loc, Intval (Right_Opnd (N)))); |
| Append_To (Exprs, Then_Expr); |
| |
| Set_Left_Opnd (Else_Expr, |
| Unchecked_Convert_To (Standard_Unsigned, |
| New_Copy_Tree (Left_Opnd (N)))); |
| Set_Right_Opnd (Else_Expr, |
| Make_Integer_Literal (Loc, Mod_Minus_Right)); |
| Append_To (Exprs, Else_Expr); |
| |
| Rewrite (N, |
| Unchecked_Convert_To (Typ, |
| Make_If_Expression (Loc, Expressions => Exprs))); |
| end; |
| end if; |
| end Expand_Modular_Addition; |
| |
| ----------------------- |
| -- Expand_Modular_Op -- |
| ----------------------- |
| |
| procedure Expand_Modular_Op is |
| Op_Expr : constant Node_Id := New_Op_Node (Nkind (N), Loc); |
| Mod_Expr : constant Node_Id := New_Op_Node (N_Op_Mod, Loc); |
| |
| Target_Type : Entity_Id; |
| |
| begin |
| -- Convert nonbinary modular type operands into integer values. Thus |
| -- we avoid never-ending loops expanding them, and we also ensure |
| -- the back end never receives nonbinary modular type expressions. |
| |
| if Nkind (N) in N_Op_And | N_Op_Or | N_Op_Xor then |
| Set_Left_Opnd (Op_Expr, |
| Unchecked_Convert_To (Standard_Unsigned, |
| New_Copy_Tree (Left_Opnd (N)))); |
| Set_Right_Opnd (Op_Expr, |
| Unchecked_Convert_To (Standard_Unsigned, |
| New_Copy_Tree (Right_Opnd (N)))); |
| Set_Left_Opnd (Mod_Expr, |
| Unchecked_Convert_To (Standard_Integer, Op_Expr)); |
| |
| else |
| -- If the modulus of the type is larger than Integer'Last use a |
| -- larger type for the operands, to prevent spurious constraint |
| -- errors on large legal literals of the type. |
| |
| if Modulus (Etype (N)) > Int (Integer'Last) then |
| Target_Type := Standard_Long_Long_Integer; |
| else |
| Target_Type := Standard_Integer; |
| end if; |
| |
| Set_Left_Opnd (Op_Expr, |
| Unchecked_Convert_To (Target_Type, |
| New_Copy_Tree (Left_Opnd (N)))); |
| Set_Right_Opnd (Op_Expr, |
| Unchecked_Convert_To (Target_Type, |
| New_Copy_Tree (Right_Opnd (N)))); |
| |
| -- Link this node to the tree to analyze it |
| |
| -- If the parent node is an expression with actions we link it to |
| -- N since otherwise Force_Evaluation cannot identify if this node |
| -- comes from the Expression and rejects generating the temporary. |
| |
| if Nkind (Parent (N)) = N_Expression_With_Actions then |
| Set_Parent (Op_Expr, N); |
| |
| -- Common case |
| |
| else |
| Set_Parent (Op_Expr, Parent (N)); |
| end if; |
| |
| Analyze (Op_Expr); |
| |
| -- Force generating a temporary because in the expansion of this |
| -- expression we may generate code that performs this computation |
| -- several times. |
| |
| Force_Evaluation (Op_Expr, Mode => Strict); |
| |
| Set_Left_Opnd (Mod_Expr, Op_Expr); |
| end if; |
| |
| Set_Right_Opnd (Mod_Expr, |
| Make_Integer_Literal (Loc, Modulus (Typ))); |
| |
| Rewrite (N, |
| Unchecked_Convert_To (Typ, Mod_Expr)); |
| end Expand_Modular_Op; |
| |
| -------------------------------- |
| -- Expand_Modular_Subtraction -- |
| -------------------------------- |
| |
| procedure Expand_Modular_Subtraction is |
| begin |
| -- If this is not the addition of a constant then compute it using |
| -- the general rule: (lhs + rhs) mod Modulus |
| |
| if Nkind (Right_Opnd (N)) /= N_Integer_Literal then |
| Expand_Modular_Op; |
| |
| -- If this is an addition of a constant, convert it to a subtraction |
| -- plus a conditional expression since we can compute it faster than |
| -- computing the modulus. |
| |
| -- modMinusRhs = Modulus - rhs |
| -- if lhs < rhs then lhs + modMinusRhs |
| -- else lhs - rhs |
| |
| else |
| declare |
| Mod_Minus_Right : constant Uint := |
| Modulus (Typ) - Intval (Right_Opnd (N)); |
| |
| Exprs : constant List_Id := New_List; |
| Cond_Expr : constant Node_Id := New_Op_Node (N_Op_Lt, Loc); |
| Then_Expr : constant Node_Id := New_Op_Node (N_Op_Add, Loc); |
| Else_Expr : constant Node_Id := New_Op_Node (N_Op_Subtract, |
| Loc); |
| begin |
| Set_Left_Opnd (Cond_Expr, |
| Unchecked_Convert_To (Standard_Unsigned, |
| New_Copy_Tree (Left_Opnd (N)))); |
| Set_Right_Opnd (Cond_Expr, |
| Make_Integer_Literal (Loc, Intval (Right_Opnd (N)))); |
| Append_To (Exprs, Cond_Expr); |
| |
| Set_Left_Opnd (Then_Expr, |
| Unchecked_Convert_To (Standard_Unsigned, |
| New_Copy_Tree (Left_Opnd (N)))); |
| Set_Right_Opnd (Then_Expr, |
| Make_Integer_Literal (Loc, Mod_Minus_Right)); |
| Append_To (Exprs, Then_Expr); |
| |
| Set_Left_Opnd (Else_Expr, |
| Unchecked_Convert_To (Standard_Unsigned, |
| New_Copy_Tree (Left_Opnd (N)))); |
| Set_Right_Opnd (Else_Expr, |
| Unchecked_Convert_To (Standard_Unsigned, |
| New_Copy_Tree (Right_Opnd (N)))); |
| Append_To (Exprs, Else_Expr); |
| |
| Rewrite (N, |
| Unchecked_Convert_To (Typ, |
| Make_If_Expression (Loc, Expressions => Exprs))); |
| end; |
| end if; |
| end Expand_Modular_Subtraction; |
| |
| -- Start of processing for Expand_Nonbinary_Modular_Op |
| |
| begin |
| -- No action needed if front-end expansion is not required or if we |
| -- have a binary modular operand. |
| |
| if not Expand_Nonbinary_Modular_Ops |
| or else not Non_Binary_Modulus (Typ) |
| then |
| return; |
| end if; |
| |
| case Nkind (N) is |
| when N_Op_Add => |
| Expand_Modular_Addition; |
| |
| when N_Op_Subtract => |
| Expand_Modular_Subtraction; |
| |
| when N_Op_Minus => |
| |
| -- Expand -expr into (0 - expr) |
| |
| Rewrite (N, |
| Make_Op_Subtract (Loc, |
| Left_Opnd => Make_Integer_Literal (Loc, 0), |
| Right_Opnd => Right_Opnd (N))); |
| Analyze_And_Resolve (N, Typ); |
| |
| when others => |
| Expand_Modular_Op; |
| end case; |
| |
| Analyze_And_Resolve (N, Typ); |
| end Expand_Nonbinary_Modular_Op; |
| |
| ------------------------ |
| -- Expand_N_Allocator -- |
| ------------------------ |
| |
| procedure Expand_N_Allocator (N : Node_Id) is |
| Etyp : constant Entity_Id := Etype (Expression (N)); |
| Loc : constant Source_Ptr := Sloc (N); |
| PtrT : constant Entity_Id := Etype (N); |
| |
| procedure Rewrite_Coextension (N : Node_Id); |
| -- Static coextensions have the same lifetime as the entity they |
| -- constrain. Such occurrences can be rewritten as aliased objects |
| -- and their unrestricted access used instead of the coextension. |
| |
| function Size_In_Storage_Elements (E : Entity_Id) return Node_Id; |
| -- Given a constrained array type E, returns a node representing the |
| -- code to compute a close approximation of the size in storage elements |
| -- for the given type; for indexes that are modular types we compute |
| -- 'Last - First (instead of 'Length) because for large arrays computing |
| -- 'Last -'First + 1 causes overflow. This is done without using the |
| -- attribute 'Size_In_Storage_Elements (which malfunctions for large |
| -- sizes ???). |
| |
| ------------------------- |
| -- Rewrite_Coextension -- |
| ------------------------- |
| |
| procedure Rewrite_Coextension (N : Node_Id) is |
| Temp_Id : constant Node_Id := Make_Temporary (Loc, 'C'); |
| Temp_Decl : Node_Id; |
| |
| begin |
| -- Generate: |
| -- Cnn : aliased Etyp; |
| |
| Temp_Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp_Id, |
| Aliased_Present => True, |
| Object_Definition => New_Occurrence_Of (Etyp, Loc)); |
| |
| if Nkind (Expression (N)) = N_Qualified_Expression then |
| Set_Expression (Temp_Decl, Expression (Expression (N))); |
| end if; |
| |
| Insert_Action (N, Temp_Decl); |
| Rewrite (N, |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Temp_Id, Loc), |
| Attribute_Name => Name_Unrestricted_Access)); |
| |
| Analyze_And_Resolve (N, PtrT); |
| end Rewrite_Coextension; |
| |
| ------------------------------ |
| -- Size_In_Storage_Elements -- |
| ------------------------------ |
| |
| function Size_In_Storage_Elements (E : Entity_Id) return Node_Id is |
| Idx : Node_Id := First_Index (E); |
| Len : Node_Id; |
| Res : Node_Id := Empty; |
| |
| begin |
| -- Logically this just returns E'Max_Size_In_Storage_Elements. |
| -- However, the reason for the existence of this function is to |
| -- construct a test for sizes too large, which means near the 32-bit |
| -- limit on a 32-bit machine, and precisely the trouble is that we |
| -- get overflows when sizes are greater than 2**31. |
| |
| -- So what we end up doing for array types is to use the expression: |
| |
| -- number-of-elements * component_type'Max_Size_In_Storage_Elements |
| |
| -- which avoids this problem. All this is a bit bogus, but it does |
| -- mean we catch common cases of trying to allocate arrays that are |
| -- too large, and which in the absence of a check results in |
| -- undetected chaos ??? |
| |
| for J in 1 .. Number_Dimensions (E) loop |
| |
| if not Is_Modular_Integer_Type (Etype (Idx)) then |
| Len := |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (E, Loc), |
| Attribute_Name => Name_Length, |
| Expressions => New_List (Make_Integer_Literal (Loc, J))); |
| |
| -- For indexes that are modular types we cannot generate code to |
| -- compute 'Length since for large arrays 'Last -'First + 1 causes |
| -- overflow; therefore we compute 'Last - 'First (which is not the |
| -- exact number of components but it is valid for the purpose of |
| -- this runtime check on 32-bit targets). |
| |
| else |
| declare |
| Len_Minus_1_Expr : Node_Id; |
| Test_Gt : Node_Id; |
| |
| begin |
| Test_Gt := |
| Make_Op_Gt (Loc, |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (E, Loc), |
| Attribute_Name => Name_Last, |
| Expressions => |
| New_List (Make_Integer_Literal (Loc, J))), |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (E, Loc), |
| Attribute_Name => Name_First, |
| Expressions => |
| New_List (Make_Integer_Literal (Loc, J)))); |
| |
| Len_Minus_1_Expr := |
| Convert_To (Standard_Unsigned, |
| Make_Op_Subtract (Loc, |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (E, Loc), |
| Attribute_Name => Name_Last, |
| Expressions => |
| New_List (Make_Integer_Literal (Loc, J))), |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (E, Loc), |
| Attribute_Name => Name_First, |
| Expressions => |
| New_List (Make_Integer_Literal (Loc, J))))); |
| |
| -- Handle superflat arrays, i.e. arrays with such bounds as |
| -- 4 .. 2, to ensure that the result is correct. |
| |
| -- Generate: |
| -- (if X'Last > X'First then X'Last - X'First else 0) |
| |
| Len := |
| Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Test_Gt, |
| Len_Minus_1_Expr, |
| Make_Integer_Literal (Loc, Uint_0))); |
| end; |
| end if; |
| |
| if J = 1 then |
| Res := Len; |
| |
| else |
| pragma Assert (Present (Res)); |
| Res := |
| Make_Op_Multiply (Loc, |
| Left_Opnd => Res, |
| Right_Opnd => Len); |
| end if; |
| |
| Next_Index (Idx); |
| end loop; |
| |
| return |
| Make_Op_Multiply (Loc, |
| Left_Opnd => Len, |
| Right_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Component_Type (E), Loc), |
| Attribute_Name => Name_Max_Size_In_Storage_Elements)); |
| end Size_In_Storage_Elements; |
| |
| -- Local variables |
| |
| Dtyp : constant Entity_Id := Available_View (Designated_Type (PtrT)); |
| Desig : Entity_Id; |
| Nod : Node_Id; |
| Pool : Entity_Id; |
| Rel_Typ : Entity_Id; |
| Temp : Entity_Id; |
| |
| -- Start of processing for Expand_N_Allocator |
| |
| begin |
| -- Warn on the presence of an allocator of an anonymous access type when |
| -- enabled, except when it's an object declaration at library level. |
| |
| if Warn_On_Anonymous_Allocators |
| and then Ekind (PtrT) = E_Anonymous_Access_Type |
| and then not (Is_Library_Level_Entity (PtrT) |
| and then Nkind (Associated_Node_For_Itype (PtrT)) = |
| N_Object_Declaration) |
| then |
| Error_Msg_N ("?_a?use of an anonymous access type allocator", N); |
| end if; |
| |
| -- RM E.2.2(17). We enforce that the expected type of an allocator |
| -- shall not be a remote access-to-class-wide-limited-private type. |
| -- We probably shouldn't be doing this legality check during expansion, |
| -- but this is only an issue for Annex E users, and is unlikely to be a |
| -- problem in practice. |
| |
| Validate_Remote_Access_To_Class_Wide_Type (N); |
| |
| -- Processing for anonymous access-to-controlled types. These access |
| -- types receive a special finalization master which appears in the |
| -- declarations of the enclosing semantic unit. This expansion is done |
| -- now to ensure that any additional types generated by this routine or |
| -- Expand_Allocator_Expression inherit the proper type attributes. |
| |
| if (Ekind (PtrT) = E_Anonymous_Access_Type |
| or else (Is_Itype (PtrT) and then No (Finalization_Master (PtrT)))) |
| and then Needs_Finalization (Dtyp) |
| then |
| -- Detect the allocation of an anonymous controlled object where the |
| -- type of the context is named. For example: |
| |
| -- procedure Proc (Ptr : Named_Access_Typ); |
| -- Proc (new Designated_Typ); |
| |
| -- Regardless of the anonymous-to-named access type conversion, the |
| -- lifetime of the object must be associated with the named access |
| -- type. Use the finalization-related attributes of this type. |
| |
| if Nkind (Parent (N)) in N_Type_Conversion |
| | N_Unchecked_Type_Conversion |
| and then Ekind (Etype (Parent (N))) in E_Access_Subtype |
| | E_Access_Type |
| | E_General_Access_Type |
| then |
| Rel_Typ := Etype (Parent (N)); |
| else |
| Rel_Typ := Empty; |
| end if; |
| |
| -- Anonymous access-to-controlled types allocate on the global pool. |
| -- Note that this is a "root type only" attribute. |
| |
| if No (Associated_Storage_Pool (PtrT)) then |
| if Present (Rel_Typ) then |
| Set_Associated_Storage_Pool |
| (Root_Type (PtrT), Associated_Storage_Pool (Rel_Typ)); |
| else |
| Set_Associated_Storage_Pool |
| (Root_Type (PtrT), RTE (RE_Global_Pool_Object)); |
| end if; |
| end if; |
| |
| -- The finalization master must be inserted and analyzed as part of |
| -- the current semantic unit. Note that the master is updated when |
| -- analysis changes current units. Note that this is a "root type |
| -- only" attribute. |
| |
| if Present (Rel_Typ) then |
| Set_Finalization_Master |
| (Root_Type (PtrT), Finalization_Master (Rel_Typ)); |
| else |
| Build_Anonymous_Master (Root_Type (PtrT)); |
| end if; |
| end if; |
| |
| -- Set the storage pool and find the appropriate version of Allocate to |
| -- call. Do not overwrite the storage pool if it is already set, which |
| -- can happen for build-in-place function returns (see |
| -- Exp_Ch4.Expand_N_Extended_Return_Statement). |
| |
| if No (Storage_Pool (N)) then |
| Pool := Associated_Storage_Pool (Root_Type (PtrT)); |
| |
| if Present (Pool) then |
| Set_Storage_Pool (N, Pool); |
| |
| if Is_RTE (Pool, RE_RS_Pool) then |
| Set_Procedure_To_Call (N, RTE (RE_RS_Allocate)); |
| |
| elsif Is_RTE (Pool, RE_SS_Pool) then |
| Check_Restriction (No_Secondary_Stack, N); |
| Set_Procedure_To_Call (N, RTE (RE_SS_Allocate)); |
| |
| -- In the case of an allocator for a simple storage pool, locate |
| -- and save a reference to the pool type's Allocate routine. |
| |
| elsif Present (Get_Rep_Pragma |
| (Etype (Pool), Name_Simple_Storage_Pool_Type)) |
| then |
| declare |
| Pool_Type : constant Entity_Id := Base_Type (Etype (Pool)); |
| Alloc_Op : Entity_Id; |
| begin |
| Alloc_Op := Get_Name_Entity_Id (Name_Allocate); |
| while Present (Alloc_Op) loop |
| if Scope (Alloc_Op) = Scope (Pool_Type) |
| and then Present (First_Formal (Alloc_Op)) |
| and then Etype (First_Formal (Alloc_Op)) = Pool_Type |
| then |
| Set_Procedure_To_Call (N, Alloc_Op); |
| exit; |
| else |
| Alloc_Op := Homonym (Alloc_Op); |
| end if; |
| end loop; |
| end; |
| |
| elsif Is_Class_Wide_Type (Etype (Pool)) then |
| Set_Procedure_To_Call (N, RTE (RE_Allocate_Any)); |
| |
| else |
| Set_Procedure_To_Call (N, |
| Find_Storage_Op (Etype (Pool), Name_Allocate)); |
| end if; |
| end if; |
| end if; |
| |
| -- Under certain circumstances we can replace an allocator by an access |
| -- to statically allocated storage. The conditions, as noted in AARM |
| -- 3.10 (10c) are as follows: |
| |
| -- Size and initial value is known at compile time |
| -- Access type is access-to-constant |
| |
| -- The allocator is not part of a constraint on a record component, |
| -- because in that case the inserted actions are delayed until the |
| -- record declaration is fully analyzed, which is too late for the |
| -- analysis of the rewritten allocator. |
| |
| if Is_Access_Constant (PtrT) |
| and then Nkind (Expression (N)) = N_Qualified_Expression |
| and then Compile_Time_Known_Value (Expression (Expression (N))) |
| and then Size_Known_At_Compile_Time |
| (Etype (Expression (Expression (N)))) |
| and then not Is_Record_Type (Current_Scope) |
| then |
| -- Here we can do the optimization. For the allocator |
| |
| -- new x'(y) |
| |
| -- We insert an object declaration |
| |
| -- Tnn : aliased x := y; |
| |
| -- and replace the allocator by Tnn'Unrestricted_Access. Tnn is |
| -- marked as requiring static allocation. |
| |
| Temp := Make_Temporary (Loc, 'T', Expression (Expression (N))); |
| Desig := Subtype_Mark (Expression (N)); |
| |
| -- If context is constrained, use constrained subtype directly, |
| -- so that the constant is not labelled as having a nominally |
| -- unconstrained subtype. |
| |
| if Entity (Desig) = Base_Type (Dtyp) then |
| Desig := New_Occurrence_Of (Dtyp, Loc); |
| end if; |
| |
| Insert_Action (N, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Aliased_Present => True, |
| Constant_Present => Is_Access_Constant (PtrT), |
| Object_Definition => Desig, |
| Expression => Expression (Expression (N)))); |
| |
| Rewrite (N, |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Temp, Loc), |
| Attribute_Name => Name_Unrestricted_Access)); |
| |
| Analyze_And_Resolve (N, PtrT); |
| |
| -- We set the variable as statically allocated, since we don't want |
| -- it going on the stack of the current procedure. |
| |
| Set_Is_Statically_Allocated (Temp); |
| return; |
| end if; |
| |
| -- Same if the allocator is an access discriminant for a local object: |
| -- instead of an allocator we create a local value and constrain the |
| -- enclosing object with the corresponding access attribute. |
| |
| if Is_Static_Coextension (N) then |
| Rewrite_Coextension (N); |
| return; |
| end if; |
| |
| -- Check for size too large, we do this because the back end misses |
| -- proper checks here and can generate rubbish allocation calls when |
| -- we are near the limit. We only do this for the 32-bit address case |
| -- since that is from a practical point of view where we see a problem. |
| |
| if System_Address_Size = 32 |
| and then not Storage_Checks_Suppressed (PtrT) |
| and then not Storage_Checks_Suppressed (Dtyp) |
| and then not Storage_Checks_Suppressed (Etyp) |
| then |
| -- The check we want to generate should look like |
| |
| -- if Etyp'Max_Size_In_Storage_Elements > 3.5 gigabytes then |
| -- raise Storage_Error; |
| -- end if; |
| |
| -- where 3.5 gigabytes is a constant large enough to accommodate any |
| -- reasonable request for. But we can't do it this way because at |
| -- least at the moment we don't compute this attribute right, and |
| -- can silently give wrong results when the result gets large. Since |
| -- this is all about large results, that's bad, so instead we only |
| -- apply the check for constrained arrays, and manually compute the |
| -- value of the attribute ??? |
| |
| -- The check on No_Initialization is used here to prevent generating |
| -- this runtime check twice when the allocator is locally replaced by |
| -- the expander with another one. |
| |
| if Is_Array_Type (Etyp) and then not No_Initialization (N) then |
| declare |
| Cond : Node_Id; |
| Ins_Nod : Node_Id := N; |
| Siz_Typ : Entity_Id := Etyp; |
| Expr : Node_Id; |
| |
| begin |
| -- For unconstrained array types initialized with a qualified |
| -- expression we use its type to perform this check |
| |
| if not Is_Constrained (Etyp) |
| and then not No_Initialization (N) |
| and then Nkind (Expression (N)) = N_Qualified_Expression |
| then |
| Expr := Expression (Expression (N)); |
| Siz_Typ := Etype (Expression (Expression (N))); |
| |
| -- If the qualified expression has been moved to an internal |
| -- temporary (to remove side effects) then we must insert |
| -- the runtime check before its declaration to ensure that |
| -- the check is performed before the execution of the code |
| -- computing the qualified expression. |
| |
| if Nkind (Expr) = N_Identifier |
| and then Is_Internal_Name (Chars (Expr)) |
| and then |
| Nkind (Parent (Entity (Expr))) = N_Object_Declaration |
| then |
| Ins_Nod := Parent (Entity (Expr)); |
| else |
| Ins_Nod := Expr; |
| end if; |
| end if; |
| |
| if Is_Constrained (Siz_Typ) |
| and then Ekind (Siz_Typ) /= E_String_Literal_Subtype |
| then |
| -- For CCG targets, the largest array may have up to 2**31-1 |
| -- components (i.e. 2 gigabytes if each array component is |
| -- one byte). This ensures that fat pointer fields do not |
| -- overflow, since they are 32-bit integer types, and also |
| -- ensures that 'Length can be computed at run time. |
| |
| if Modify_Tree_For_C then |
| Cond := |
| Make_Op_Gt (Loc, |
| Left_Opnd => Size_In_Storage_Elements (Siz_Typ), |
| Right_Opnd => Make_Integer_Literal (Loc, |
| Uint_2 ** 31 - Uint_1)); |
| |
| -- For native targets the largest object is 3.5 gigabytes |
| |
| else |
| Cond := |
| Make_Op_Gt (Loc, |
| Left_Opnd => Size_In_Storage_Elements (Siz_Typ), |
| Right_Opnd => Make_Integer_Literal (Loc, |
| Uint_7 * (Uint_2 ** 29))); |
| end if; |
| |
| Insert_Action (Ins_Nod, |
| Make_Raise_Storage_Error (Loc, |
| Condition => Cond, |
| Reason => SE_Object_Too_Large)); |
| |
| if Entity (Cond) = Standard_True then |
| Error_Msg_N |
| ("object too large: Storage_Error will be raised at " |
| & "run time??", N); |
| end if; |
| end if; |
| end; |
| end if; |
| end if; |
| |
| -- If no storage pool has been specified, or the storage pool |
| -- is System.Pool_Global.Global_Pool_Object, and the restriction |
| -- No_Standard_Allocators_After_Elaboration is present, then generate |
| -- a call to Elaboration_Allocators.Check_Standard_Allocator. |
| |
| if Nkind (N) = N_Allocator |
| and then (No (Storage_Pool (N)) |
| or else Is_RTE (Storage_Pool (N), RE_Global_Pool_Object)) |
| and then Restriction_Active (No_Standard_Allocators_After_Elaboration) |
| then |
| Insert_Action (N, |
| Make_Procedure_Call_Statement (Loc, |
| Name => |
| New_Occurrence_Of (RTE (RE_Check_Standard_Allocator), Loc))); |
| end if; |
| |
| -- Handle case of qualified expression (other than optimization above) |
| |
| if Nkind (Expression (N)) = N_Qualified_Expression then |
| Expand_Allocator_Expression (N); |
| return; |
| end if; |
| |
| -- If the allocator is for a type which requires initialization, and |
| -- there is no initial value (i.e. operand is a subtype indication |
| -- rather than a qualified expression), then we must generate a call to |
| -- the initialization routine using an expressions action node: |
| |
| -- [Pnnn : constant ptr_T := new (T); Init (Pnnn.all,...); Pnnn] |
| |
| -- Here ptr_T is the pointer type for the allocator, and T is the |
| -- subtype of the allocator. A special case arises if the designated |
| -- type of the access type is a task or contains tasks. In this case |
| -- the call to Init (Temp.all ...) is replaced by code that ensures |
| -- that tasks get activated (see Exp_Ch9.Build_Task_Allocate_Block |
| -- for details). In addition, if the type T is a task type, then the |
| -- first argument to Init must be converted to the task record type. |
| |
| declare |
| T : constant Entity_Id := Etype (Expression (N)); |
| Args : List_Id; |
| Decls : List_Id; |
| Decl : Node_Id; |
| Discr : Elmt_Id; |
| Init : Entity_Id; |
| Init_Arg1 : Node_Id; |
| Init_Call : Node_Id; |
| Temp_Decl : Node_Id; |
| Temp_Type : Entity_Id; |
| |
| begin |
| -- Apply constraint checks against designated subtype (RM 4.8(10/2)) |
| -- but ignore the expression if the No_Initialization flag is set. |
| -- Discriminant checks will be generated by the expansion below. |
| |
| if Is_Array_Type (Dtyp) and then not No_Initialization (N) then |
| Apply_Constraint_Check (Expression (N), Dtyp, No_Sliding => True); |
| |
| Apply_Predicate_Check (Expression (N), Dtyp); |
| |
| if Nkind (Expression (N)) = N_Raise_Constraint_Error then |
| Rewrite (N, New_Copy (Expression (N))); |
| Set_Etype (N, PtrT); |
| return; |
| end if; |
| end if; |
| |
| if No_Initialization (N) then |
| |
| -- Even though this might be a simple allocation, create a custom |
| -- Allocate if the context requires it. |
| |
| if Present (Finalization_Master (PtrT)) then |
| Build_Allocate_Deallocate_Proc |
| (N => N, |
| Is_Allocate => True); |
| end if; |
| |
| -- Optimize the default allocation of an array object when pragma |
| -- Initialize_Scalars or Normalize_Scalars is in effect. Construct an |
| -- in-place initialization aggregate which may be convert into a fast |
| -- memset by the backend. |
| |
| elsif Init_Or_Norm_Scalars |
| and then Is_Array_Type (T) |
| |
| -- The array must lack atomic components because they are treated |
| -- as non-static, and as a result the backend will not initialize |
| -- the memory in one go. |
| |
| and then not Has_Atomic_Components (T) |
| |
| -- The array must not be packed because the invalid values in |
| -- System.Scalar_Values are multiples of Storage_Unit. |
| |
| and then not Is_Packed (T) |
| |
| -- The array must have static non-empty ranges, otherwise the |
| -- backend cannot initialize the memory in one go. |
| |
| and then Has_Static_Non_Empty_Array_Bounds (T) |
| |
| -- The optimization is only relevant for arrays of scalar types |
| |
| and then Is_Scalar_Type (Component_Type (T)) |
| |
| -- Similar to regular array initialization using a type init proc, |
| -- predicate checks are not performed because the initialization |
| -- values are intentionally invalid, and may violate the predicate. |
| |
| and then not Has_Predicates (Component_Type (T)) |
| |
| -- The component type must have a single initialization value |
| |
| and then Needs_Simple_Initialization |
| (Typ => Component_Type (T), |
| Consider_IS => True) |
| then |
| Set_Analyzed (N); |
| Temp := Make_Temporary (Loc, 'P'); |
| |
| -- Generate: |
| -- Temp : Ptr_Typ := new ...; |
| |
| Insert_Action |
| (Assoc_Node => N, |
| Ins_Action => |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Object_Definition => New_Occurrence_Of (PtrT, Loc), |
| Expression => Relocate_Node (N)), |
| Suppress => All_Checks); |
| |
| -- Generate: |
| -- Temp.all := (others => ...); |
| |
| Insert_Action |
| (Assoc_Node => N, |
| Ins_Action => |
| Make_Assignment_Statement (Loc, |
| Name => |
| Make_Explicit_Dereference (Loc, |
| Prefix => New_Occurrence_Of (Temp, Loc)), |
| Expression => |
| Get_Simple_Init_Val |
| (Typ => T, |
| N => N, |
| Size => Esize (Component_Type (T)))), |
| Suppress => All_Checks); |
| |
| Rewrite (N, New_Occurrence_Of (Temp, Loc)); |
| Analyze_And_Resolve (N, PtrT); |
| |
| -- Case of no initialization procedure present |
| |
| elsif not Has_Non_Null_Base_Init_Proc (T) then |
| |
| -- Case of simple initialization required |
| |
| if Needs_Simple_Initialization (T) then |
| Check_Restriction (No_Default_Initialization, N); |
| Rewrite (Expression (N), |
| Make_Qualified_Expression (Loc, |
| Subtype_Mark => New_Occurrence_Of (T, Loc), |
| Expression => Get_Simple_Init_Val (T, N))); |
| |
| Analyze_And_Resolve (Expression (Expression (N)), T); |
| Analyze_And_Resolve (Expression (N), T); |
| Set_Paren_Count (Expression (Expression (N)), 1); |
| Expand_N_Allocator (N); |
| |
| -- No initialization required |
| |
| else |
| Build_Allocate_Deallocate_Proc |
| (N => N, |
| Is_Allocate => True); |
| end if; |
| |
| -- Case of initialization procedure present, must be called |
| |
| -- NOTE: There is a *huge* amount of code duplication here from |
| -- Build_Initialization_Call. We should probably refactor??? |
| |
| else |
| Check_Restriction (No_Default_Initialization, N); |
| |
| if not Restriction_Active (No_Default_Initialization) then |
| Init := Base_Init_Proc (T); |
| Nod := N; |
| Temp := Make_Temporary (Loc, 'P'); |
| |
| -- Construct argument list for the initialization routine call |
| |
| Init_Arg1 := |
| Make_Explicit_Dereference (Loc, |
| Prefix => |
| New_Occurrence_Of (Temp, Loc)); |
| |
| Set_Assignment_OK (Init_Arg1); |
| Temp_Type := PtrT; |
| |
| -- The initialization procedure expects a specific type. if the |
| -- context is access to class wide, indicate that the object |
| -- being allocated has the right specific type. |
| |
| if Is_Class_Wide_Type (Dtyp) then |
| Init_Arg1 := Unchecked_Convert_To (T, Init_Arg1); |
| end if; |
| |
| -- If designated type is a concurrent type or if it is private |
| -- type whose definition is a concurrent type, the first |
| -- argument in the Init routine has to be unchecked conversion |
| -- to the corresponding record type. If the designated type is |
| -- a derived type, also convert the argument to its root type. |
| |
| if Is_Concurrent_Type (T) then |
| Init_Arg1 := |
| Unchecked_Convert_To ( |
| Corresponding_Record_Type (T), Init_Arg1); |
| |
| elsif Is_Private_Type (T) |
| and then Present (Full_View (T)) |
| and then Is_Concurrent_Type (Full_View (T)) |
| then |
| Init_Arg1 := |
| Unchecked_Convert_To |
| (Corresponding_Record_Type (Full_View (T)), Init_Arg1); |
| |
| elsif Etype (First_Formal (Init)) /= Base_Type (T) then |
| declare |
| Ftyp : constant Entity_Id := Etype (First_Formal (Init)); |
| |
| begin |
| Init_Arg1 := OK_Convert_To (Etype (Ftyp), Init_Arg1); |
| Set_Etype (Init_Arg1, Ftyp); |
| end; |
| end if; |
| |
| Args := New_List (Init_Arg1); |
| |
| -- For the task case, pass the Master_Id of the access type as |
| -- the value of the _Master parameter, and _Chain as the value |
| -- of the _Chain parameter (_Chain will be defined as part of |
| -- the generated code for the allocator). |
| |
| -- In Ada 2005, the context may be a function that returns an |
| -- anonymous access type. In that case the Master_Id has been |
| -- created when expanding the function declaration. |
| |
| if Has_Task (T) then |
| if No (Master_Id (Base_Type (PtrT))) then |
| |
| -- The designated type was an incomplete type, and the |
| -- access type did not get expanded. Salvage it now. |
| |
| if Present (Parent (Base_Type (PtrT))) then |
| Expand_N_Full_Type_Declaration |
| (Parent (Base_Type (PtrT))); |
| |
| -- The only other possibility is an itype. For this |
| -- case, the master must exist in the context. This is |
| -- the case when the allocator initializes an access |
| -- component in an init-proc. |
| |
| else |
| pragma Assert (Is_Itype (PtrT)); |
| Build_Master_Renaming (PtrT, N); |
| end if; |
| end if; |
| |
| -- If the context of the allocator is a declaration or an |
| -- assignment, we can generate a meaningful image for it, |
| -- even though subsequent assignments might remove the |
| -- connection between task and entity. We build this image |
| -- when the left-hand side is a simple variable, a simple |
| -- indexed assignment or a simple selected component. |
| |
| if Nkind (Parent (N)) = N_Assignment_Statement then |
| declare |
| Nam : constant Node_Id := Name (Parent (N)); |
| |
| begin |
| if Is_Entity_Name (Nam) then |
| Decls := |
| Build_Task_Image_Decls |
| (Loc, |
| New_Occurrence_Of |
| (Entity (Nam), Sloc (Nam)), T); |
| |
| elsif Nkind (Nam) in N_Indexed_Component |
| | N_Selected_Component |
| and then Is_Entity_Name (Prefix (Nam)) |
| then |
| Decls := |
| Build_Task_Image_Decls |
| (Loc, Nam, Etype (Prefix (Nam))); |
| else |
| Decls := Build_Task_Image_Decls (Loc, T, T); |
| end if; |
| end; |
| |
| elsif Nkind (Parent (N)) = N_Object_Declaration then |
| Decls := |
| Build_Task_Image_Decls |
| (Loc, Defining_Identifier (Parent (N)), T); |
| |
| else |
| Decls := Build_Task_Image_Decls (Loc, T, T); |
| end if; |
| |
| if Restriction_Active (No_Task_Hierarchy) then |
| Append_To |
| (Args, Make_Integer_Literal (Loc, Library_Task_Level)); |
| else |
| Append_To (Args, |
| New_Occurrence_Of |
| (Master_Id (Base_Type (Root_Type (PtrT))), Loc)); |
| end if; |
| |
| Append_To (Args, Make_Identifier (Loc, Name_uChain)); |
| |
| Decl := Last (Decls); |
| Append_To (Args, |
| New_Occurrence_Of (Defining_Identifier (Decl), Loc)); |
| |
| -- Has_Task is false, Decls not used |
| |
| else |
| Decls := No_List; |
| end if; |
| |
| -- Add discriminants if discriminated type |
| |
| declare |
| Dis : Boolean := False; |
| Typ : Entity_Id := Empty; |
| |
| begin |
| if Has_Discriminants (T) then |
| Dis := True; |
| Typ := T; |
| |
| -- Type may be a private type with no visible discriminants |
| -- in which case check full view if in scope, or the |
| -- underlying_full_view if dealing with a type whose full |
| -- view may be derived from a private type whose own full |
| -- view has discriminants. |
| |
| elsif Is_Private_Type (T) then |
| if Present (Full_View (T)) |
| and then Has_Discriminants (Full_View (T)) |
| then |
| Dis := True; |
| Typ := Full_View (T); |
| |
| elsif Present (Underlying_Full_View (T)) |
| and then Has_Discriminants (Underlying_Full_View (T)) |
| then |
| Dis := True; |
| Typ := Underlying_Full_View (T); |
| end if; |
| end if; |
| |
| if Dis then |
| |
| -- If the allocated object will be constrained by the |
| -- default values for discriminants, then build a subtype |
| -- with those defaults, and change the allocated subtype |
| -- to that. Note that this happens in fewer cases in Ada |
| -- 2005 (AI-363). |
| |
| if not Is_Constrained (Typ) |
| and then Present (Discriminant_Default_Value |
| (First_Discriminant (Typ))) |
| and then (Ada_Version < Ada_2005 |
| or else not |
| Object_Type_Has_Constrained_Partial_View |
| (Typ, Current_Scope)) |
| then |
| Typ := Build_Default_Subtype (Typ, N); |
| Set_Expression (N, New_Occurrence_Of (Typ, Loc)); |
| end if; |
| |
| -- When the designated subtype is unconstrained and |
| -- the allocator specifies a constrained subtype (or |
| -- such a subtype has been created, such as above by |
| -- Build_Default_Subtype), associate that subtype with |
| -- the dereference of the allocator's access value. |
| -- This is needed by the back end for cases where |
| -- the access type has a Designated_Storage_Model, |
| -- to support allocation of a host object of the right |
| -- size for passing to the initialization procedure. |
| |
| if not Is_Constrained (Dtyp) |
| and then Is_Constrained (Typ) |
| then |
| declare |
| Init_Deref : constant Node_Id := |
| Unqual_Conv (Init_Arg1); |
| begin |
| pragma Assert |
| (Nkind (Init_Deref) = N_Explicit_Dereference); |
| |
| Set_Actual_Designated_Subtype (Init_Deref, Typ); |
| end; |
| end if; |
| |
| Discr := First_Elmt (Discriminant_Constraint (Typ)); |
| while Present (Discr) loop |
| Nod := Node (Discr); |
| Append (New_Copy_Tree (Node (Discr)), Args); |
| |
| -- AI-416: when the discriminant constraint is an |
| -- anonymous access type make sure an accessibility |
| -- check is inserted if necessary (3.10.2(22.q/2)) |
| |
| if Ada_Version >= Ada_2005 |
| and then |
| Ekind (Etype (Nod)) = E_Anonymous_Access_Type |
| and then not |
| No_Dynamic_Accessibility_Checks_Enabled (Nod) |
| then |
| Apply_Accessibility_Check |
| (Nod, Typ, Insert_Node => Nod); |
| end if; |
| |
| Next_Elmt (Discr); |
| end loop; |
| end if; |
| end; |
| |
| -- We set the allocator as analyzed so that when we analyze |
| -- the if expression node, we do not get an unwanted recursive |
| -- expansion of the allocator expression. |
| |
| Set_Analyzed (N, True); |
| Nod := Relocate_Node (N); |
| |
| -- Here is the transformation: |
| -- input: new Ctrl_Typ |
| -- output: Temp : constant Ctrl_Typ_Ptr := new Ctrl_Typ; |
| -- Ctrl_TypIP (Temp.all, ...); |
| -- [Deep_]Initialize (Temp.all); |
| |
| -- Here Ctrl_Typ_Ptr is the pointer type for the allocator, and |
| -- is the subtype of the allocator. |
| |
| Temp_Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Constant_Present => True, |
| Object_Definition => New_Occurrence_Of (Temp_Type, Loc), |
| Expression => Nod); |
| |
| Set_Assignment_OK (Temp_Decl); |
| Insert_Action (N, Temp_Decl, Suppress => All_Checks); |
| |
| Build_Allocate_Deallocate_Proc (Temp_Decl, True); |
| |
| -- If the designated type is a task type or contains tasks, |
| -- create block to activate created tasks, and insert |
| -- declaration for Task_Image variable ahead of call. |
| |
| if Has_Task (T) then |
| declare |
| L : constant List_Id := New_List; |
| Blk : Node_Id; |
| begin |
| Build_Task_Allocate_Block (L, Nod, Args); |
| Blk := Last (L); |
| Insert_List_Before (First (Declarations (Blk)), Decls); |
| Insert_Actions (N, L); |
| end; |
| |
| else |
| Insert_Action (N, |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (Init, Loc), |
| Parameter_Associations => Args)); |
| end if; |
| |
| if Needs_Finalization (T) then |
| |
| -- Generate: |
| -- [Deep_]Initialize (Init_Arg1); |
| |
| Init_Call := |
| Make_Init_Call |
| (Obj_Ref => New_Copy_Tree (Init_Arg1), |
| Typ => T); |
| |
| -- Guard against a missing [Deep_]Initialize when the |
| -- designated type was not properly frozen. |
| |
| if Present (Init_Call) then |
| Insert_Action (N, Init_Call); |
| end if; |
| end if; |
| |
| Rewrite (N, New_Occurrence_Of (Temp, Loc)); |
| Analyze_And_Resolve (N, PtrT); |
| |
| -- When designated type has Default_Initial_Condition aspects, |
| -- make a call to the type's DIC procedure to perform the |
| -- checks. Theoretically this might also be needed for cases |
| -- where the type doesn't have an init proc, but those should |
| -- be very uncommon, and for now we only support the init proc |
| -- case. ??? |
| |
| if Has_DIC (Dtyp) |
| and then Present (DIC_Procedure (Dtyp)) |
| and then not Has_Null_Body (DIC_Procedure (Dtyp)) |
| then |
| Insert_Action (N, |
| Build_DIC_Call (Loc, |
| Make_Explicit_Dereference (Loc, |
| Prefix => New_Occurrence_Of (Temp, Loc)), |
| Dtyp)); |
| end if; |
| end if; |
| end if; |
| end; |
| |
| -- Ada 2005 (AI-251): If the allocator is for a class-wide interface |
| -- object that has been rewritten as a reference, we displace "this" |
| -- to reference properly its secondary dispatch table. |
| |
| if Nkind (N) = N_Identifier and then Is_Interface (Dtyp) then |
| Displace_Allocator_Pointer (N); |
| end if; |
| |
| exception |
| when RE_Not_Available => |
| return; |
| end Expand_N_Allocator; |
| |
| ----------------------- |
| -- Expand_N_And_Then -- |
| ----------------------- |
| |
| procedure Expand_N_And_Then (N : Node_Id) |
| renames Expand_Short_Circuit_Operator; |
| |
| ------------------------------ |
| -- Expand_N_Case_Expression -- |
| ------------------------------ |
| |
| procedure Expand_N_Case_Expression (N : Node_Id) is |
| function Is_Copy_Type (Typ : Entity_Id) return Boolean; |
| -- Return True if we can copy objects of this type when expanding a case |
| -- expression. |
| |
| ------------------ |
| -- Is_Copy_Type -- |
| ------------------ |
| |
| function Is_Copy_Type (Typ : Entity_Id) return Boolean is |
| begin |
| -- If Minimize_Expression_With_Actions is True, we can afford to copy |
| -- large objects, as long as they are constrained and not limited. |
| |
| return |
| Is_Elementary_Type (Underlying_Type (Typ)) |
| or else |
| (Minimize_Expression_With_Actions |
| and then Is_Constrained (Underlying_Type (Typ)) |
| and then not Is_Limited_Type (Underlying_Type (Typ))); |
| end Is_Copy_Type; |
| |
| -- Local variables |
| |
| Loc : constant Source_Ptr := Sloc (N); |
| Par : constant Node_Id := Parent (N); |
| Typ : constant Entity_Id := Etype (N); |
| |
| Acts : List_Id; |
| Alt : Node_Id; |
| Case_Stmt : Node_Id; |
| Decl : Node_Id; |
| Expr : Node_Id; |
| Target : Entity_Id := Empty; |
| Target_Typ : Entity_Id; |
| |
| In_Predicate : Boolean := False; |
| -- Flag set when the case expression appears within a predicate |
| |
| Optimize_Return_Stmt : Boolean := False; |
| -- Flag set when the case expression can be optimized in the context of |
| -- a simple return statement. |
| |
| -- Start of processing for Expand_N_Case_Expression |
| |
| begin |
| -- Check for MINIMIZED/ELIMINATED overflow mode |
| |
| if Minimized_Eliminated_Overflow_Check (N) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- If the case expression is a predicate specification, and the type |
| -- to which it applies has a static predicate aspect, do not expand, |
| -- because it will be converted to the proper predicate form later. |
| |
| if Ekind (Current_Scope) in E_Function | E_Procedure |
| and then Is_Predicate_Function (Current_Scope) |
| then |
| In_Predicate := True; |
| |
| if Has_Static_Predicate_Aspect (Etype (First_Entity (Current_Scope))) |
| then |
| return; |
| end if; |
| end if; |
| |
| -- When the type of the case expression is elementary, expand |
| |
| -- (case X is when A => AX, when B => BX ...) |
| |
| -- into |
| |
| -- do |
| -- Target : Typ; |
| -- case X is |
| -- when A => |
| -- Target := AX; |
| -- when B => |
| -- Target := BX; |
| -- ... |
| -- end case; |
| -- in Target end; |
| |
| -- In all other cases expand into |
| |
| -- do |
| -- type Ptr_Typ is access all Typ; |
| -- Target : Ptr_Typ; |
| -- case X is |
| -- when A => |
| -- Target := AX'Unrestricted_Access; |
| -- when B => |
| -- Target := BX'Unrestricted_Access; |
| -- ... |
| -- end case; |
| -- in Target.all end; |
| |
| -- This approach avoids extra copies of potentially large objects. It |
| -- also allows handling of values of limited or unconstrained types. |
| -- Note that we do the copy also for constrained, nonlimited types |
| -- when minimizing expressions with actions (e.g. when generating C |
| -- code) since it allows us to do the optimization below in more cases. |
| |
| -- Small optimization: when the case expression appears in the context |
| -- of a simple return statement, expand into |
| |
| -- case X is |
| -- when A => |
| -- return AX; |
| -- when B => |
| -- return BX; |
| -- ... |
| -- end case; |
| |
| Case_Stmt := |
| Make_Case_Statement (Loc, |
| Expression => Expression (N), |
| Alternatives => New_List); |
| |
| -- Preserve the original context for which the case statement is being |
| -- generated. This is needed by the finalization machinery to prevent |
| -- the premature finalization of controlled objects found within the |
| -- case statement. |
| |
| Set_From_Conditional_Expression (Case_Stmt); |
| Acts := New_List; |
| |
| -- Scalar/Copy case |
| |
| if Is_Copy_Type (Typ) then |
| Target_Typ := Typ; |
| |
| -- Do not perform the optimization when the return statement is |
| -- within a predicate function, as this causes spurious errors. |
| |
| Optimize_Return_Stmt := |
| Nkind (Par) = N_Simple_Return_Statement and then not In_Predicate; |
| |
| -- Otherwise create an access type to handle the general case using |
| -- 'Unrestricted_Access. |
| |
| -- Generate: |
| -- type Ptr_Typ is access all Typ; |
| |
| else |
| if Generate_C_Code then |
| |
| -- We cannot ensure that correct C code will be generated if any |
| -- temporary is created down the line (to e.g. handle checks or |
| -- capture values) since we might end up with dangling references |
| -- to local variables, so better be safe and reject the construct. |
| |
| Error_Msg_N |
| ("case expression too complex, use case statement instead", N); |
| end if; |
| |
| Target_Typ := Make_Temporary (Loc, 'P'); |
| |
| Append_To (Acts, |
| Make_Full_Type_Declaration (Loc, |
| Defining_Identifier => Target_Typ, |
| Type_Definition => |
| Make_Access_To_Object_Definition (Loc, |
| All_Present => True, |
| Subtype_Indication => New_Occurrence_Of (Typ, Loc)))); |
| end if; |
| |
| -- Create the declaration of the target which captures the value of the |
| -- expression. |
| |
| -- Generate: |
| -- Target : [Ptr_]Typ; |
| |
| if not Optimize_Return_Stmt then |
| Target := Make_Temporary (Loc, 'T'); |
| |
| Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Target, |
| Object_Definition => New_Occurrence_Of (Target_Typ, Loc)); |
| Set_No_Initialization (Decl); |
| |
| Append_To (Acts, Decl); |
| end if; |
| |
| -- Process the alternatives |
| |
| Alt := First (Alternatives (N)); |
| while Present (Alt) loop |
| declare |
| Alt_Expr : Node_Id := Expression (Alt); |
| Alt_Loc : constant Source_Ptr := Sloc (Alt_Expr); |
| LHS : Node_Id; |
| Stmts : List_Id; |
| |
| begin |
| -- Take the unrestricted access of the expression value for non- |
| -- scalar types. This approach avoids big copies and covers the |
| -- limited and unconstrained cases. |
| |
| -- Generate: |
| -- AX'Unrestricted_Access |
| |
| if not Is_Copy_Type (Typ) then |
| Alt_Expr := |
| Make_Attribute_Reference (Alt_Loc, |
| Prefix => Relocate_Node (Alt_Expr), |
| Attribute_Name => Name_Unrestricted_Access); |
| end if; |
| |
| -- Generate: |
| -- return AX['Unrestricted_Access]; |
| |
| if Optimize_Return_Stmt then |
| Stmts := New_List ( |
| Make_Simple_Return_Statement (Alt_Loc, |
| Expression => Alt_Expr)); |
| |
| -- Generate: |
| -- Target := AX['Unrestricted_Access]; |
| |
| else |
| LHS := New_Occurrence_Of (Target, Loc); |
| Set_Assignment_OK (LHS); |
| |
| Stmts := New_List ( |
| Make_Assignment_Statement (Alt_Loc, |
| Name => LHS, |
| Expression => Alt_Expr)); |
| end if; |
| |
| -- Propagate declarations inserted in the node by Insert_Actions |
| -- (for example, temporaries generated to remove side effects). |
| -- These actions must remain attached to the alternative, given |
| -- that they are generated by the corresponding expression. |
| |
| if Present (Actions (Alt)) then |
| Prepend_List (Actions (Alt), Stmts); |
| end if; |
| |
| -- Finalize any transient objects on exit from the alternative. |
| -- This is done only in the return optimization case because |
| -- otherwise the case expression is converted into an expression |
| -- with actions which already contains this form of processing. |
| |
| if Optimize_Return_Stmt then |
| Process_If_Case_Statements (N, Stmts); |
| end if; |
| |
| Append_To |
| (Alternatives (Case_Stmt), |
| Make_Case_Statement_Alternative (Sloc (Alt), |
| Discrete_Choices => Discrete_Choices (Alt), |
| Statements => Stmts)); |
| end; |
| |
| Next (Alt); |
| end loop; |
| |
| -- Rewrite the parent return statement as a case statement |
| |
| if Optimize_Return_Stmt then |
| Rewrite (Par, Case_Stmt); |
| Analyze (Par); |
| |
| -- Otherwise convert the case expression into an expression with actions |
| |
| else |
| Append_To (Acts, Case_Stmt); |
| |
| if Is_Copy_Type (Typ) then |
| Expr := New_Occurrence_Of (Target, Loc); |
| |
| else |
| Expr := |
| Make_Explicit_Dereference (Loc, |
| Prefix => New_Occurrence_Of (Target, Loc)); |
| end if; |
| |
| -- Generate: |
| -- do |
| -- ... |
| -- in Target[.all] end; |
| |
| Rewrite (N, |
| Make_Expression_With_Actions (Loc, |
| Expression => Expr, |
| Actions => Acts)); |
| |
| Analyze_And_Resolve (N, Typ); |
| end if; |
| end Expand_N_Case_Expression; |
| |
| ----------------------------------- |
| -- Expand_N_Explicit_Dereference -- |
| ----------------------------------- |
| |
| procedure Expand_N_Explicit_Dereference (N : Node_Id) is |
| begin |
| -- Insert explicit dereference call for the checked storage pool case |
| |
| Insert_Dereference_Action (Prefix (N)); |
| |
| -- If the type is an Atomic type for which Atomic_Sync is enabled, then |
| -- we set the atomic sync flag. |
| |
| if Is_Atomic (Etype (N)) |
| and then not Atomic_Synchronization_Disabled (Etype (N)) |
| then |
| Activate_Atomic_Synchronization (N); |
| end if; |
| end Expand_N_Explicit_Dereference; |
| |
| -------------------------------------- |
| -- Expand_N_Expression_With_Actions -- |
| -------------------------------------- |
| |
| procedure Expand_N_Expression_With_Actions (N : Node_Id) is |
| Acts : constant List_Id := Actions (N); |
| |
| procedure Force_Boolean_Evaluation (Expr : Node_Id); |
| -- Force the evaluation of Boolean expression Expr |
| |
| function Process_Action (Act : Node_Id) return Traverse_Result; |
| -- Inspect and process a single action of an expression_with_actions for |
| -- transient objects. If such objects are found, the routine generates |
| -- code to clean them up when the context of the expression is evaluated |
| -- or elaborated. |
| |
| ------------------------------ |
| -- Force_Boolean_Evaluation -- |
| ------------------------------ |
| |
| procedure Force_Boolean_Evaluation (Expr : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Flag_Decl : Node_Id; |
| Flag_Id : Entity_Id; |
| |
| begin |
| -- Relocate the expression to the actions list by capturing its value |
| -- in a Boolean flag. Generate: |
| -- Flag : constant Boolean := Expr; |
| |
| Flag_Id := Make_Temporary (Loc, 'F'); |
| |
| Flag_Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Flag_Id, |
| Constant_Present => True, |
| Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc), |
| Expression => Relocate_Node (Expr)); |
| |
| Append (Flag_Decl, Acts); |
| Analyze (Flag_Decl); |
| |
| -- Replace the expression with a reference to the flag |
| |
| Rewrite (Expression (N), New_Occurrence_Of (Flag_Id, Loc)); |
| Analyze (Expression (N)); |
| end Force_Boolean_Evaluation; |
| |
| -------------------- |
| -- Process_Action -- |
| -------------------- |
| |
| function Process_Action (Act : Node_Id) return Traverse_Result is |
| begin |
| if Nkind (Act) = N_Object_Declaration |
| and then Is_Finalizable_Transient (Act, N) |
| then |
| Process_Transient_In_Expression (Act, N, Acts); |
| return Skip; |
| |
| -- Avoid processing temporary function results multiple times when |
| -- dealing with nested expression_with_actions. |
| -- Similarly, do not process temporary function results in loops. |
| -- This is done by Expand_N_Loop_Statement and Build_Finalizer. |
| -- Note that we used to wrongly return Abandon instead of Skip here: |
| -- this is wrong since it means that we were ignoring lots of |
| -- relevant subsequent statements. |
| |
| elsif Nkind (Act) in N_Expression_With_Actions | N_Loop_Statement then |
| return Skip; |
| end if; |
| |
| return OK; |
| end Process_Action; |
| |
| procedure Process_Single_Action is new Traverse_Proc (Process_Action); |
| |
| -- Local variables |
| |
| Act : Node_Id; |
| |
| -- Start of processing for Expand_N_Expression_With_Actions |
| |
| begin |
| -- Do not evaluate the expression when it denotes an entity because the |
| -- expression_with_actions node will be replaced by the reference. |
| |
| if Is_Entity_Name (Expression (N)) then |
| null; |
| |
| -- Do not evaluate the expression when there are no actions because the |
| -- expression_with_actions node will be replaced by the expression. |
| |
| elsif Is_Empty_List (Acts) then |
| null; |
| |
| -- Force the evaluation of the expression by capturing its value in a |
| -- temporary. This ensures that aliases of transient objects do not leak |
| -- to the expression of the expression_with_actions node: |
| |
| -- do |
| -- Trans_Id : Ctrl_Typ := ...; |
| -- Alias : ... := Trans_Id; |
| -- in ... Alias ... end; |
| |
| -- In the example above, Trans_Id cannot be finalized at the end of the |
| -- actions list because this may affect the alias and the final value of |
| -- the expression_with_actions. Forcing the evaluation encapsulates the |
| -- reference to the Alias within the actions list: |
| |
| -- do |
| -- Trans_Id : Ctrl_Typ := ...; |
| -- Alias : ... := Trans_Id; |
| -- Val : constant Boolean := ... Alias ...; |
| -- <finalize Trans_Id> |
| -- in Val end; |
| |
| -- Once this transformation is performed, it is safe to finalize the |
| -- transient object at the end of the actions list. |
| |
| -- Note that Force_Evaluation does not remove side effects in operators |
| -- because it assumes that all operands are evaluated and side effect |
| -- free. This is not the case when an operand depends implicitly on the |
| -- transient object through the use of access types. |
| |
| elsif Is_Boolean_Type (Etype (Expression (N))) then |
| Force_Boolean_Evaluation (Expression (N)); |
| |
| -- The expression of an expression_with_actions node may not necessarily |
| -- be Boolean when the node appears in an if expression. In this case do |
| -- the usual forced evaluation to encapsulate potential aliasing. |
| |
| else |
| Force_Evaluation (Expression (N)); |
| end if; |
| |
| -- Process all transient objects found within the actions of the EWA |
| -- node. |
| |
| Act := First (Acts); |
| while Present (Act) loop |
| Process_Single_Action (Act); |
| Next (Act); |
| end loop; |
| |
| -- Deal with case where there are no actions. In this case we simply |
| -- rewrite the node with its expression since we don't need the actions |
| -- and the specification of this node does not allow a null action list. |
| |
| -- Note: we use Rewrite instead of Replace, because Codepeer is using |
| -- the expanded tree and relying on being able to retrieve the original |
| -- tree in cases like this. This raises a whole lot of issues of whether |
| -- we have problems elsewhere, which will be addressed in the future??? |
| |
| if Is_Empty_List (Acts) then |
| Rewrite (N, Relocate_Node (Expression (N))); |
| end if; |
| end Expand_N_Expression_With_Actions; |
| |
| ---------------------------- |
| -- Expand_N_If_Expression -- |
| ---------------------------- |
| |
| -- Deal with limited types and condition actions |
| |
| procedure Expand_N_If_Expression (N : Node_Id) is |
| Cond : constant Node_Id := First (Expressions (N)); |
| Loc : constant Source_Ptr := Sloc (N); |
| Thenx : constant Node_Id := Next (Cond); |
| Elsex : constant Node_Id := Next (Thenx); |
| Typ : constant Entity_Id := Etype (N); |
| |
| Force_Expand : constant Boolean := Is_Anonymous_Access_Actual (N); |
| -- Determine if we are dealing with a special case of a conditional |
| -- expression used as an actual for an anonymous access type which |
| -- forces us to transform the if expression into an expression with |
| -- actions in order to create a temporary to capture the level of the |
| -- expression in each branch. |
| |
| function OK_For_Single_Subtype (T1, T2 : Entity_Id) return Boolean; |
| -- Return true if it is acceptable to use a single subtype for two |
| -- dependent expressions of subtype T1 and T2 respectively, which are |
| -- unidimensional arrays whose index bounds are known at compile time. |
| |
| --------------------------- |
| -- OK_For_Single_Subtype -- |
| --------------------------- |
| |
| function OK_For_Single_Subtype (T1, T2 : Entity_Id) return Boolean is |
| Lo1, Hi1 : Uint; |
| Lo2, Hi2 : Uint; |
| |
| begin |
| Get_First_Index_Bounds (T1, Lo1, Hi1); |
| Get_First_Index_Bounds (T2, Lo2, Hi2); |
| |
| -- Return true if the length of the covering subtype is not too large |
| |
| return |
| UI_Max (Hi1, Hi2) - UI_Min (Lo1, Lo2) < Too_Large_Length_For_Array; |
| end OK_For_Single_Subtype; |
| |
| -- Local variables |
| |
| Actions : List_Id; |
| Decl : Node_Id; |
| Expr : Node_Id; |
| New_If : Node_Id; |
| New_N : Node_Id; |
| |
| -- Start of processing for Expand_N_If_Expression |
| |
| begin |
| -- Deal with non-standard booleans |
| |
| Adjust_Condition (Cond); |
| |
| -- Check for MINIMIZED/ELIMINATED overflow mode. |
| -- Apply_Arithmetic_Overflow_Check will not deal with Then/Else_Actions |
| -- so skip this step if any actions are present. |
| |
| if Minimized_Eliminated_Overflow_Check (N) |
| and then No (Then_Actions (N)) |
| and then No (Else_Actions (N)) |
| then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- Fold at compile time if condition known. We have already folded |
| -- static if expressions, but it is possible to fold any case in which |
| -- the condition is known at compile time, even though the result is |
| -- non-static. |
| |
| -- Note that we don't do the fold of such cases in Sem_Elab because |
| -- it can cause infinite loops with the expander adding a conditional |
| -- expression, and Sem_Elab circuitry removing it repeatedly. |
| |
| if Compile_Time_Known_Value (Cond) then |
| declare |
| function Fold_Known_Value (Cond : Node_Id) return Boolean; |
| -- Fold at compile time. Assumes condition known. Return True if |
| -- folding occurred, meaning we're done. |
| |
| ---------------------- |
| -- Fold_Known_Value -- |
| ---------------------- |
| |
| function Fold_Known_Value (Cond : Node_Id) return Boolean is |
| begin |
| if Is_True (Expr_Value (Cond)) then |
| Expr := Thenx; |
| Actions := Then_Actions (N); |
| else |
| Expr := Elsex; |
| Actions := Else_Actions (N); |
| end if; |
| |
| Remove (Expr); |
| |
| if Present (Actions) then |
| |
| -- To minimize the use of Expression_With_Actions, just skip |
| -- the optimization as it is not critical for correctness. |
| |
| if Minimize_Expression_With_Actions then |
| return False; |
| end if; |
| |
| Rewrite (N, |
| Make_Expression_With_Actions (Loc, |
| Expression => Relocate_Node (Expr), |
| Actions => Actions)); |
| Analyze_And_Resolve (N, Typ); |
| |
| else |
| Rewrite (N, Relocate_Node (Expr)); |
| end if; |
| |
| -- Note that the result is never static (legitimate cases of |
| -- static if expressions were folded in Sem_Eval). |
| |
| Set_Is_Static_Expression (N, False); |
| return True; |
| end Fold_Known_Value; |
| |
| begin |
| if Fold_Known_Value (Cond) then |
| return; |
| end if; |
| end; |
| end if; |
| |
| -- If the type is limited, and the back end does not handle limited |
| -- types, then we expand as follows to avoid the possibility of |
| -- improper copying. |
| |
| -- type Ptr is access all Typ; |
| -- Cnn : Ptr; |
| -- if cond then |
| -- <<then actions>> |
| -- Cnn := then-expr'Unrestricted_Access; |
| -- else |
| -- <<else actions>> |
| -- Cnn := else-expr'Unrestricted_Access; |
| -- end if; |
| |
| -- and replace the if expression by a reference to Cnn.all. |
| |
| -- This special case can be skipped if the back end handles limited |
| -- types properly and ensures that no incorrect copies are made. |
| |
| if Is_By_Reference_Type (Typ) |
| and then not Back_End_Handles_Limited_Types |
| then |
| -- When the "then" or "else" expressions involve controlled function |
| -- calls, generated temporaries are chained on the corresponding list |
| -- of actions. These temporaries need to be finalized after the if |
| -- expression is evaluated. |
| |
| Process_If_Case_Statements (N, Then_Actions (N)); |
| Process_If_Case_Statements (N, Else_Actions (N)); |
| |
| declare |
| Cnn : constant Entity_Id := Make_Temporary (Loc, 'C', N); |
| Ptr_Typ : constant Entity_Id := Make_Temporary (Loc, 'A'); |
| |
| begin |
| -- Generate: |
| -- type Ann is access all Typ; |
| |
| Insert_Action (N, |
| Make_Full_Type_Declaration (Loc, |
| Defining_Identifier => Ptr_Typ, |
| Type_Definition => |
| Make_Access_To_Object_Definition (Loc, |
| All_Present => True, |
| Subtype_Indication => New_Occurrence_Of (Typ, Loc)))); |
| |
| -- Generate: |
| -- Cnn : Ann; |
| |
| Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Cnn, |
| Object_Definition => New_Occurrence_Of (Ptr_Typ, Loc)); |
| |
| -- Generate: |
| -- if Cond then |
| -- Cnn := <Thenx>'Unrestricted_Access; |
| -- else |
| -- Cnn := <Elsex>'Unrestricted_Access; |
| -- end if; |
| |
| New_If := |
| Make_Implicit_If_Statement (N, |
| Condition => Relocate_Node (Cond), |
| Then_Statements => New_List ( |
| Make_Assignment_Statement (Sloc (Thenx), |
| Name => New_Occurrence_Of (Cnn, Sloc (Thenx)), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => Relocate_Node (Thenx), |
| Attribute_Name => Name_Unrestricted_Access))), |
| |
| Else_Statements => New_List ( |
| Make_Assignment_Statement (Sloc (Elsex), |
| Name => New_Occurrence_Of (Cnn, Sloc (Elsex)), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => Relocate_Node (Elsex), |
| Attribute_Name => Name_Unrestricted_Access)))); |
| |
| -- Preserve the original context for which the if statement is |
| -- being generated. This is needed by the finalization machinery |
| -- to prevent the premature finalization of controlled objects |
| -- found within the if statement. |
| |
| Set_From_Conditional_Expression (New_If); |
| |
| New_N := |
| Make_Explicit_Dereference (Loc, |
| Prefix => New_Occurrence_Of (Cnn, Loc)); |
| end; |
| |
| -- If the result is a unidimensional unconstrained array but the two |
| -- dependent expressions have constrained subtypes with known bounds, |
| -- then we expand as follows: |
| |
| -- subtype Txx is Typ (<static low-bound> .. <static high-bound>); |
| -- Cnn : Txx; |
| -- if cond then |
| -- <<then actions>> |
| -- Cnn (<then low-bound .. then high-bound>) := then-expr; |
| -- else |
| -- <<else actions>> |
| -- Cnn (<else low bound .. else high-bound>) := else-expr; |
| -- end if; |
| |
| -- and replace the if expression by a slice of Cnn, provided that Txx |
| -- is not too large. This will create a static temporary instead of the |
| -- dynamic one of the next case and thus help the code generator. |
| |
| -- Note that we need to deal with the case where the else expression is |
| -- itself such a slice, in order to catch if expressions with more than |
| -- two dependent expressions in the source code. |
| |
| elsif Is_Array_Type (Typ) |
| and then Number_Dimensions (Typ) = 1 |
| and then not Is_Constrained (Typ) |
| and then Is_Constrained (Etype (Thenx)) |
| and then Compile_Time_Known_Bounds (Etype (Thenx)) |
| and then |
| ((Is_Constrained (Etype (Elsex)) |
| and then Compile_Time_Known_Bounds (Etype (Elsex)) |
| and then OK_For_Single_Subtype (Etype (Thenx), Etype (Elsex))) |
| or else |
| (Nkind (Elsex) = N_Slice |
| and then Is_Constrained (Etype (Prefix (Elsex))) |
| and then Compile_Time_Known_Bounds (Etype (Prefix (Elsex))) |
| and then |
| OK_For_Single_Subtype (Etype (Thenx), Etype (Prefix (Elsex))))) |
| and then not Generate_C_Code |
| then |
| declare |
| Ityp : constant Entity_Id := Base_Type (Etype (First_Index (Typ))); |
| |
| function Build_New_Bound |
| (Then_Bnd : Uint; |
| Else_Bnd : Uint; |
| Slice_Bnd : Node_Id) return Node_Id; |
| -- Build a new bound from the bounds of the if expression |
| |
| function To_Ityp (V : Uint) return Node_Id; |
| -- Convert V to an index value in Ityp |
| |
| --------------------- |
| -- Build_New_Bound -- |
| --------------------- |
| |
| function Build_New_Bound |
| (Then_Bnd : Uint; |
| Else_Bnd : Uint; |
| Slice_Bnd : Node_Id) return Node_Id is |
| |
| begin |
| if Nkind (Elsex) = N_Slice then |
| if Compile_Time_Known_Value (Slice_Bnd) |
| and then Expr_Value (Slice_Bnd) = Then_Bnd |
| then |
| return To_Ityp (Then_Bnd); |
| |
| else |
| return Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Duplicate_Subexpr (Cond), |
| To_Ityp (Then_Bnd), |
| New_Copy_Tree (Slice_Bnd))); |
| end if; |
| |
| elsif Then_Bnd = Else_Bnd then |
| return To_Ityp (Then_Bnd); |
| |
| else |
| return Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Duplicate_Subexpr (Cond), |
| To_Ityp (Then_Bnd), |
| To_Ityp (Else_Bnd))); |
| end if; |
| end Build_New_Bound; |
| |
| ------------- |
| -- To_Ityp -- |
| ------------- |
| |
| function To_Ityp (V : Uint) return Node_Id is |
| Result : constant Node_Id := Make_Integer_Literal (Loc, V); |
| |
| begin |
| if Is_Enumeration_Type (Ityp) then |
| return |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Ityp, Loc), |
| Attribute_Name => Name_Val, |
| Expressions => New_List (Result)); |
| else |
| return Result; |
| end if; |
| end To_Ityp; |
| |
| Ent : Node_Id; |
| Slice_Lo, Slice_Hi : Node_Id; |
| Subtyp_Ind : Node_Id; |
| Else_Lo, Else_Hi : Uint; |
| Min_Lo, Max_Hi : Uint; |
| Then_Lo, Then_Hi : Uint; |
| Then_List, Else_List : List_Id; |
| |
| begin |
| Get_First_Index_Bounds (Etype (Thenx), Then_Lo, Then_Hi); |
| |
| if Nkind (Elsex) = N_Slice then |
| Slice_Lo := Low_Bound (Discrete_Range (Elsex)); |
| Slice_Hi := High_Bound (Discrete_Range (Elsex)); |
| Get_First_Index_Bounds |
| (Etype (Prefix (Elsex)), Else_Lo, Else_Hi); |
| |
| else |
| Slice_Lo := Empty; |
| Slice_Hi := Empty; |
| Get_First_Index_Bounds (Etype (Elsex), Else_Lo, Else_Hi); |
| end if; |
| |
| Min_Lo := UI_Min (Then_Lo, Else_Lo); |
| Max_Hi := UI_Max (Then_Hi, Else_Hi); |
| |
| -- Now we construct an array object with appropriate bounds and |
| -- mark it as internal to prevent useless initialization when |
| -- Initialize_Scalars is enabled. Also since this is the actual |
| -- result entity, we make sure we have debug information for it. |
| |
| Subtyp_Ind := |
| Make_Subtype_Indication (Loc, |
| Subtype_Mark => New_Occurrence_Of (Typ, Loc), |
| Constraint => |
| Make_Index_Or_Discriminant_Constraint (Loc, |
| Constraints => New_List ( |
| Make_Range (Loc, |
| Low_Bound => To_Ityp (Min_Lo), |
| High_Bound => To_Ityp (Max_Hi))))); |
| |
| Ent := Make_Temporary (Loc, 'C'); |
| Set_Is_Internal (Ent); |
| Set_Debug_Info_Needed (Ent); |
| |
| Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Ent, |
| Object_Definition => Subtyp_Ind); |
| |
| -- If the result of the expression appears as the initializing |
| -- expression of an object declaration, we can just rename the |
| -- result, rather than copying it. |
| |
| Mutate_Ekind (Ent, E_Variable); |
| Set_OK_To_Rename (Ent); |
| |
| Then_List := New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => |
| Make_Slice (Loc, |
| Prefix => New_Occurrence_Of (Ent, Loc), |
| Discrete_Range => |
| Make_Range (Loc, |
| Low_Bound => To_Ityp (Then_Lo), |
| High_Bound => To_Ityp (Then_Hi))), |
| Expression => Relocate_Node (Thenx))); |
| |
| Set_Suppress_Assignment_Checks (Last (Then_List)); |
| |
| if Nkind (Elsex) = N_Slice then |
| Else_List := New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => |
| Make_Slice (Loc, |
| Prefix => New_Occurrence_Of (Ent, Loc), |
| Discrete_Range => |
| Make_Range (Loc, |
| Low_Bound => New_Copy_Tree (Slice_Lo), |
| High_Bound => New_Copy_Tree (Slice_Hi))), |
| Expression => Relocate_Node (Elsex))); |
| |
| else |
| Else_List := New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => |
| Make_Slice (Loc, |
| Prefix => New_Occurrence_Of (Ent, Loc), |
| Discrete_Range => |
| Make_Range (Loc, |
| Low_Bound => To_Ityp (Else_Lo), |
| High_Bound => To_Ityp (Else_Hi))), |
| Expression => Relocate_Node (Elsex))); |
| end if; |
| |
| Set_Suppress_Assignment_Checks (Last (Else_List)); |
| |
| New_If := |
| Make_Implicit_If_Statement (N, |
| Condition => Duplicate_Subexpr (Cond), |
| Then_Statements => Then_List, |
| Else_Statements => Else_List); |
| |
| New_N := |
| Make_Slice (Loc, |
| Prefix => New_Occurrence_Of (Ent, Loc), |
| Discrete_Range => Make_Range (Loc, |
| Low_Bound => Build_New_Bound (Then_Lo, Else_Lo, Slice_Lo), |
| High_Bound => Build_New_Bound (Then_Hi, Else_Hi, Slice_Hi))); |
| end; |
| |
| -- If the result is an unconstrained array and the if expression is in a |
| -- context other than the initializing expression of the declaration of |
| -- an object, then we pull out the if expression as follows: |
| |
| -- Cnn : constant typ := if-expression |
| |
| -- and then replace the if expression with an occurrence of Cnn. This |
| -- avoids the need in the back end to create on-the-fly variable length |
| -- temporaries (which it cannot do!) |
| |
| -- Note that the test for being in an object declaration avoids doing an |
| -- unnecessary expansion, and also avoids infinite recursion. |
| |
| elsif Is_Array_Type (Typ) and then not Is_Constrained (Typ) |
| and then (Nkind (Parent (N)) /= N_Object_Declaration |
| or else Expression (Parent (N)) /= N) |
| then |
| declare |
| Cnn : constant Node_Id := Make_Temporary (Loc, 'C', N); |
| |
| begin |
| Insert_Action (N, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Cnn, |
| Constant_Present => True, |
| Object_Definition => New_Occurrence_Of (Typ, Loc), |
| Expression => Relocate_Node (N), |
| Has_Init_Expression => True)); |
| |
| Rewrite (N, New_Occurrence_Of (Cnn, Loc)); |
| return; |
| end; |
| |
| -- For other types, we only need to expand if there are other actions |
| -- associated with either branch or we need to force expansion to deal |
| -- with if expressions used as an actual of an anonymous access type. |
| |
| elsif Present (Then_Actions (N)) |
| or else Present (Else_Actions (N)) |
| or else Force_Expand |
| then |
| |
| -- We now wrap the actions into the appropriate expression |
| |
| if Minimize_Expression_With_Actions |
| and then (Is_Elementary_Type (Underlying_Type (Typ)) |
| or else Is_Constrained (Underlying_Type (Typ))) |
| then |
| -- If we can't use N_Expression_With_Actions nodes, then we insert |
| -- the following sequence of actions (using Insert_Actions): |
| |
| -- Cnn : typ; |
| -- if cond then |
| -- <<then actions>> |
| -- Cnn := then-expr; |
| -- else |
| -- <<else actions>> |
| -- Cnn := else-expr |
| -- end if; |
| |
| -- and replace the if expression by a reference to Cnn |
| |
| declare |
| Cnn : constant Node_Id := Make_Temporary (Loc, 'C', N); |
| |
| begin |
| Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Cnn, |
| Object_Definition => New_Occurrence_Of (Typ, Loc)); |
| |
| New_If := |
| Make_Implicit_If_Statement (N, |
| Condition => Relocate_Node (Cond), |
| |
| Then_Statements => New_List ( |
| Make_Assignment_Statement (Sloc (Thenx), |
| Name => New_Occurrence_Of (Cnn, Sloc (Thenx)), |
| Expression => Relocate_Node (Thenx))), |
| |
| Else_Statements => New_List ( |
| Make_Assignment_Statement (Sloc (Elsex), |
| Name => New_Occurrence_Of (Cnn, Sloc (Elsex)), |
| Expression => Relocate_Node (Elsex)))); |
| |
| Set_Assignment_OK (Name (First (Then_Statements (New_If)))); |
| Set_Assignment_OK (Name (First (Else_Statements (New_If)))); |
| |
| New_N := New_Occurrence_Of (Cnn, Loc); |
| end; |
| |
| -- Regular path using Expression_With_Actions |
| |
| else |
| if Present (Then_Actions (N)) then |
| Rewrite (Thenx, |
| Make_Expression_With_Actions (Sloc (Thenx), |
| Actions => Then_Actions (N), |
| Expression => Relocate_Node (Thenx))); |
| |
| Set_Then_Actions (N, No_List); |
| Analyze_And_Resolve (Thenx, Typ); |
| end if; |
| |
| if Present (Else_Actions (N)) then |
| Rewrite (Elsex, |
| Make_Expression_With_Actions (Sloc (Elsex), |
| Actions => Else_Actions (N), |
| Expression => Relocate_Node (Elsex))); |
| |
| Set_Else_Actions (N, No_List); |
| Analyze_And_Resolve (Elsex, Typ); |
| end if; |
| |
| -- We must force expansion into an expression with actions when |
| -- an if expression gets used directly as an actual for an |
| -- anonymous access type. |
| |
| if Force_Expand then |
| declare |
| Cnn : constant Entity_Id := Make_Temporary (Loc, 'C'); |
| Acts : List_Id; |
| begin |
| Acts := New_List; |
| |
| -- Generate: |
| -- Cnn : Ann; |
| |
| Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Cnn, |
| Object_Definition => New_Occurrence_Of (Typ, Loc)); |
| Append_To (Acts, Decl); |
| |
| Set_No_Initialization (Decl); |
| |
| -- Generate: |
| -- if Cond then |
| -- Cnn := <Thenx>; |
| -- else |
| -- Cnn := <Elsex>; |
| -- end if; |
| |
| New_If := |
| Make_Implicit_If_Statement (N, |
| Condition => Relocate_Node (Cond), |
| Then_Statements => New_List ( |
| Make_Assignment_Statement (Sloc (Thenx), |
| Name => New_Occurrence_Of (Cnn, Sloc (Thenx)), |
| Expression => Relocate_Node (Thenx))), |
| |
| Else_Statements => New_List ( |
| Make_Assignment_Statement (Sloc (Elsex), |
| Name => New_Occurrence_Of (Cnn, Sloc (Elsex)), |
| Expression => Relocate_Node (Elsex)))); |
| Append_To (Acts, New_If); |
| |
| -- Generate: |
| -- do |
| -- ... |
| -- in Cnn end; |
| |
| Rewrite (N, |
| Make_Expression_With_Actions (Loc, |
| Expression => New_Occurrence_Of (Cnn, Loc), |
| Actions => Acts)); |
| Analyze_And_Resolve (N, Typ); |
| end; |
| end if; |
| |
| return; |
| end if; |
| |
| -- For the sake of GNATcoverage, generate an intermediate temporary in |
| -- the case where the if expression is a condition in an outer decision, |
| -- in order to make sure that no branch is shared between the decisions. |
| |
| elsif Opt.Suppress_Control_Flow_Optimizations |
| and then Nkind (Original_Node (Parent (N))) in N_Case_Expression |
| | N_Case_Statement |
| | N_If_Expression |
| | N_If_Statement |
| | N_Goto_When_Statement |
| | N_Loop_Statement |
| | N_Return_When_Statement |
| | N_Short_Circuit |
| then |
| declare |
| Cnn : constant Entity_Id := Make_Temporary (Loc, 'C'); |
| Acts : List_Id; |
| |
| begin |
| -- Generate: |
| -- do |
| -- Cnn : constant Typ := N; |
| -- in Cnn end |
| |
| Acts := New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Cnn, |
| Constant_Present => True, |
| Object_Definition => New_Occurrence_Of (Typ, Loc), |
| Expression => Relocate_Node (N))); |
| |
| Rewrite (N, |
| Make_Expression_With_Actions (Loc, |
| Expression => New_Occurrence_Of (Cnn, Loc), |
| Actions => Acts)); |
| |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end; |
| |
| -- If no actions then no expansion needed, gigi will handle it using the |
| -- same approach as a C conditional expression. |
| |
| else |
| return; |
| end if; |
| |
| -- Fall through here for either the limited expansion, or the case of |
| -- inserting actions for nonlimited types. In both these cases, we must |
| -- move the SLOC of the parent If statement to the newly created one and |
| -- change it to the SLOC of the expression which, after expansion, will |
| -- correspond to what is being evaluated. |
| |
| if Present (Parent (N)) and then Nkind (Parent (N)) = N_If_Statement then |
| Set_Sloc (New_If, Sloc (Parent (N))); |
| Set_Sloc (Parent (N), Loc); |
| end if; |
| |
| -- Move Then_Actions and Else_Actions, if any, to the new if statement |
| |
| Insert_List_Before (First (Then_Statements (New_If)), Then_Actions (N)); |
| Insert_List_Before (First (Else_Statements (New_If)), Else_Actions (N)); |
| |
| Insert_Action (N, Decl); |
| Insert_Action (N, New_If); |
| Rewrite (N, New_N); |
| Analyze_And_Resolve (N, Typ); |
| end Expand_N_If_Expression; |
| |
| ----------------- |
| -- Expand_N_In -- |
| ----------------- |
| |
| procedure Expand_N_In (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Restyp : constant Entity_Id := Etype (N); |
| Lop : constant Node_Id := Left_Opnd (N); |
| Rop : constant Node_Id := Right_Opnd (N); |
| Static : constant Boolean := Is_OK_Static_Expression (N); |
| |
| procedure Substitute_Valid_Check; |
| -- Replaces node N by Lop'Valid. This is done when we have an explicit |
| -- test for the left operand being in range of its subtype. |
| |
| ---------------------------- |
| -- Substitute_Valid_Check -- |
| ---------------------------- |
| |
| procedure Substitute_Valid_Check is |
| function Is_OK_Object_Reference (Nod : Node_Id) return Boolean; |
| -- Determine whether arbitrary node Nod denotes a source object that |
| -- may safely act as prefix of attribute 'Valid. |
| |
| ---------------------------- |
| -- Is_OK_Object_Reference -- |
| ---------------------------- |
| |
| function Is_OK_Object_Reference (Nod : Node_Id) return Boolean is |
| Obj_Ref : Node_Id; |
| |
| begin |
| -- Inspect the original operand |
| |
| Obj_Ref := Original_Node (Nod); |
| |
| -- The object reference must be a source construct, otherwise the |
| -- codefix suggestion may refer to nonexistent code from a user |
| -- perspective. |
| |
| if Comes_From_Source (Obj_Ref) then |
| loop |
| if Nkind (Obj_Ref) in |
| N_Type_Conversion | |
| N_Unchecked_Type_Conversion | |
| N_Qualified_Expression |
| then |
| Obj_Ref := Expression (Obj_Ref); |
| else |
| exit; |
| end if; |
| end loop; |
| |
| return Is_Object_Reference (Obj_Ref); |
| end if; |
| |
| return False; |
| end Is_OK_Object_Reference; |
| |
| -- Start of processing for Substitute_Valid_Check |
| |
| begin |
| Rewrite (N, |
| Make_Attribute_Reference (Loc, |
| Prefix => Relocate_Node (Lop), |
| Attribute_Name => Name_Valid)); |
| |
| Analyze_And_Resolve (N, Restyp); |
| |
| -- Emit a warning when the left-hand operand of the membership test |
| -- is a source object, otherwise the use of attribute 'Valid would be |
| -- illegal. The warning is not given when overflow checking is either |
| -- MINIMIZED or ELIMINATED, as the danger of optimization has been |
| -- eliminated above. |
| |
| if Is_OK_Object_Reference (Lop) |
| and then Overflow_Check_Mode not in Minimized_Or_Eliminated |
| then |
| Error_Msg_N |
| ("??explicit membership test may be optimized away", N); |
| Error_Msg_N -- CODEFIX |
| ("\??use ''Valid attribute instead", N); |
| end if; |
| end Substitute_Valid_Check; |
| |
| -- Local variables |
| |
| Ltyp : Entity_Id; |
| Rtyp : Entity_Id; |
| |
| -- Start of processing for Expand_N_In |
| |
| begin |
| -- If set membership case, expand with separate procedure |
| |
| if Present (Alternatives (N)) then |
| Expand_Set_Membership (N); |
| return; |
| end if; |
| |
| -- Not set membership, proceed with expansion |
| |
| Ltyp := Etype (Left_Opnd (N)); |
| Rtyp := Etype (Right_Opnd (N)); |
| |
| -- If MINIMIZED/ELIMINATED overflow mode and type is a signed integer |
| -- type, then expand with a separate procedure. Note the use of the |
| -- flag No_Minimize_Eliminate to prevent infinite recursion. |
| |
| if Minimized_Eliminated_Overflow_Check (Left_Opnd (N)) |
| and then not No_Minimize_Eliminate (N) |
| then |
| Expand_Membership_Minimize_Eliminate_Overflow (N); |
| return; |
| end if; |
| |
| -- Check case of explicit test for an expression in range of its |
| -- subtype. This is suspicious usage and we replace it with a 'Valid |
| -- test and give a warning for scalar types. |
| |
| if Is_Scalar_Type (Ltyp) |
| |
| -- Only relevant for source comparisons |
| |
| and then Comes_From_Source (N) |
| |
| -- In floating-point this is a standard way to check for finite values |
| -- and using 'Valid would typically be a pessimization. |
| |
| and then not Is_Floating_Point_Type (Ltyp) |
| |
| -- Don't give the message unless right operand is a type entity and |
| -- the type of the left operand matches this type. Note that this |
| -- eliminates the cases where MINIMIZED/ELIMINATED mode overflow |
| -- checks have changed the type of the left operand. |
| |
| and then Nkind (Rop) in N_Has_Entity |
| and then Ltyp = Entity (Rop) |
| |
| -- Skip this for predicated types, where such expressions are a |
| -- reasonable way of testing if something meets the predicate. |
| |
| and then not Present (Predicate_Function (Ltyp)) |
| then |
| Substitute_Valid_Check; |
| return; |
| end if; |
| |
| -- Do validity check on operands |
| |
| if Validity_Checks_On and Validity_Check_Operands then |
| Ensure_Valid (Left_Opnd (N)); |
| Validity_Check_Range (Right_Opnd (N)); |
| end if; |
| |
| -- Case of explicit range |
| |
| if Nkind (Rop) = N_Range then |
| declare |
| Lo : constant Node_Id := Low_Bound (Rop); |
| Hi : constant Node_Id := High_Bound (Rop); |
| |
| Lo_Orig : constant Node_Id := Original_Node (Lo); |
| Hi_Orig : constant Node_Id := Original_Node (Hi); |
| |
| Lcheck : Compare_Result; |
| Ucheck : Compare_Result; |
| |
| Warn : constant Boolean := |
| Constant_Condition_Warnings |
| and then Comes_From_Source (N) |
| and then not In_Instance; |
| -- This must be true for any of the optimization warnings, we |
| -- clearly want to give them only for source with the flag on. We |
| -- also skip these warnings in an instance since it may be the |
| -- case that different instantiations have different ranges. |
| |
| begin |
| -- If test is explicit x'First .. x'Last, replace by valid check |
| |
| if Is_Scalar_Type (Ltyp) |
| |
| -- And left operand is X'First where X matches left operand |
| -- type (this eliminates cases of type mismatch, including |
| -- the cases where ELIMINATED/MINIMIZED mode has changed the |
| -- type of the left operand. |
| |
| and then Nkind (Lo_Orig) = N_Attribute_Reference |
| and then Attribute_Name (Lo_Orig) = Name_First |
| and then Nkind (Prefix (Lo_Orig)) in N_Has_Entity |
| and then Entity (Prefix (Lo_Orig)) = Ltyp |
| |
| -- Same tests for right operand |
| |
| and then Nkind (Hi_Orig) = N_Attribute_Reference |
| and then Attribute_Name (Hi_Orig) = Name_Last |
| and then Nkind (Prefix (Hi_Orig)) in N_Has_Entity |
| and then Entity (Prefix (Hi_Orig)) = Ltyp |
| |
| -- Relevant only for source cases |
| |
| and then Comes_From_Source (N) |
| then |
| Substitute_Valid_Check; |
| goto Leave; |
| end if; |
| |
| -- If bounds of type are known at compile time, and the end points |
| -- are known at compile time and identical, this is another case |
| -- for substituting a valid test. We only do this for discrete |
| -- types, since it won't arise in practice for float types. |
| |
| if Comes_From_Source (N) |
| and then Is_Discrete_Type (Ltyp) |
| and then Compile_Time_Known_Value (Type_High_Bound (Ltyp)) |
| and then Compile_Time_Known_Value (Type_Low_Bound (Ltyp)) |
| and then Compile_Time_Known_Value (Lo) |
| and then Compile_Time_Known_Value (Hi) |
| and then Expr_Value (Type_High_Bound (Ltyp)) = Expr_Value (Hi) |
| and then Expr_Value (Type_Low_Bound (Ltyp)) = Expr_Value (Lo) |
| |
| -- Kill warnings in instances, since they may be cases where we |
| -- have a test in the generic that makes sense with some types |
| -- and not with other types. |
| |
| -- Similarly, do not rewrite membership as a validity check if |
| -- within the predicate function for the type. |
| |
| -- Finally, if the original bounds are type conversions, even |
| -- if they have been folded into constants, there are different |
| -- types involved and 'Valid is not appropriate. |
| |
| then |
| if In_Instance |
| or else (Ekind (Current_Scope) = E_Function |
| and then Is_Predicate_Function (Current_Scope)) |
| then |
| null; |
| |
| elsif Nkind (Lo_Orig) = N_Type_Conversion |
| or else Nkind (Hi_Orig) = N_Type_Conversion |
| then |
| null; |
| |
| else |
| Substitute_Valid_Check; |
| goto Leave; |
| end if; |
| end if; |
| |
| -- If we have an explicit range, do a bit of optimization based on |
| -- range analysis (we may be able to kill one or both checks). |
| |
| Lcheck := Compile_Time_Compare (Lop, Lo, Assume_Valid => False); |
| Ucheck := Compile_Time_Compare (Lop, Hi, Assume_Valid => False); |
| |
| -- If either check is known to fail, replace result by False since |
| -- the other check does not matter. Preserve the static flag for |
| -- legality checks, because we are constant-folding beyond RM 4.9. |
| |
| if Lcheck = LT or else Ucheck = GT then |
| if Warn then |
| Error_Msg_N ("?c?range test optimized away", N); |
| Error_Msg_N ("\?c?value is known to be out of range", N); |
| end if; |
| |
| Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); |
| Analyze_And_Resolve (N, Restyp); |
| Set_Is_Static_Expression (N, Static); |
| goto Leave; |
| |
| -- If both checks are known to succeed, replace result by True, |
| -- since we know we are in range. |
| |
| elsif Lcheck in Compare_GE and then Ucheck in Compare_LE then |
| if Warn then |
| Error_Msg_N ("?c?range test optimized away", N); |
| Error_Msg_N ("\?c?value is known to be in range", N); |
| end if; |
| |
| Rewrite (N, New_Occurrence_Of (Standard_True, Loc)); |
| Analyze_And_Resolve (N, Restyp); |
| Set_Is_Static_Expression (N, Static); |
| goto Leave; |
| |
| -- If lower bound check succeeds and upper bound check is not |
| -- known to succeed or fail, then replace the range check with |
| -- a comparison against the upper bound. |
| |
| elsif Lcheck in Compare_GE then |
| Rewrite (N, |
| Make_Op_Le (Loc, |
| Left_Opnd => Lop, |
| Right_Opnd => High_Bound (Rop))); |
| Analyze_And_Resolve (N, Restyp); |
| goto Leave; |
| |
| -- Inverse of previous case. |
| |
| elsif Ucheck in Compare_LE then |
| Rewrite (N, |
| Make_Op_Ge (Loc, |
| Left_Opnd => Lop, |
| Right_Opnd => Low_Bound (Rop))); |
| Analyze_And_Resolve (N, Restyp); |
| goto Leave; |
| end if; |
| |
| -- We couldn't optimize away the range check, but there is one |
| -- more issue. If we are checking constant conditionals, then we |
| -- see if we can determine the outcome assuming everything is |
| -- valid, and if so give an appropriate warning. |
| |
| if Warn and then not Assume_No_Invalid_Values then |
| Lcheck := Compile_Time_Compare (Lop, Lo, Assume_Valid => True); |
| Ucheck := Compile_Time_Compare (Lop, Hi, Assume_Valid => True); |
| |
| -- Result is out of range for valid value |
| |
| if Lcheck = LT or else Ucheck = GT then |
| Error_Msg_N |
| ("?c?value can only be in range if it is invalid", N); |
| |
| -- Result is in range for valid value |
| |
| elsif Lcheck in Compare_GE and then Ucheck in Compare_LE then |
| Error_Msg_N |
| ("?c?value can only be out of range if it is invalid", N); |
| end if; |
| end if; |
| end; |
| |
| -- Try to narrow the operation |
| |
| if Ltyp = Universal_Integer and then Nkind (N) = N_In then |
| Narrow_Large_Operation (N); |
| end if; |
| |
| -- For all other cases of an explicit range, nothing to be done |
| |
| goto Leave; |
| |
| -- Here right operand is a subtype mark |
| |
| else |
| declare |
| Typ : Entity_Id := Etype (Rop); |
| Is_Acc : constant Boolean := Is_Access_Type (Typ); |
| Check_Null_Exclusion : Boolean; |
| Cond : Node_Id := Empty; |
| New_N : Node_Id; |
| Obj : Node_Id := Lop; |
| SCIL_Node : Node_Id; |
| |
| begin |
| Remove_Side_Effects (Obj); |
| |
| -- For tagged type, do tagged membership operation |
| |
| if Is_Tagged_Type (Typ) then |
| |
| -- No expansion will be performed for VM targets, as the VM |
| -- back ends will handle the membership tests directly. |
| |
| if Tagged_Type_Expansion then |
| Tagged_Membership (N, SCIL_Node, New_N); |
| Rewrite (N, New_N); |
| Analyze_And_Resolve (N, Restyp, Suppress => All_Checks); |
| |
| -- Update decoration of relocated node referenced by the |
| -- SCIL node. |
| |
| if Generate_SCIL and then Present (SCIL_Node) then |
| Set_SCIL_Node (N, SCIL_Node); |
| end if; |
| end if; |
| |
| goto Leave; |
| |
| -- If type is scalar type, rewrite as x in t'First .. t'Last. |
| -- This reason we do this is that the bounds may have the wrong |
| -- type if they come from the original type definition. Also this |
| -- way we get all the processing above for an explicit range. |
| |
| -- Don't do this for predicated types, since in this case we |
| -- want to check the predicate. |
| |
| elsif Is_Scalar_Type (Typ) then |
| if No (Predicate_Function (Typ)) then |
| Rewrite (Rop, |
| Make_Range (Loc, |
| Low_Bound => |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_First, |
| Prefix => New_Occurrence_Of (Typ, Loc)), |
| |
| High_Bound => |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Last, |
| Prefix => New_Occurrence_Of (Typ, Loc)))); |
| Analyze_And_Resolve (N, Restyp); |
| end if; |
| |
| goto Leave; |
| |
| -- Ada 2005 (AI95-0216 amended by AI12-0162): Program_Error is |
| -- raised when evaluating an individual membership test if the |
| -- subtype mark denotes a constrained Unchecked_Union subtype |
| -- and the expression lacks inferable discriminants. |
| |
| elsif Is_Unchecked_Union (Base_Type (Typ)) |
| and then Is_Constrained (Typ) |
| and then not Has_Inferable_Discriminants (Lop) |
| then |
| Rewrite (N, |
| Make_Expression_With_Actions (Loc, |
| Actions => |
| New_List (Make_Raise_Program_Error (Loc, |
| Reason => PE_Unchecked_Union_Restriction)), |
| Expression => |
| New_Occurrence_Of (Standard_False, Loc))); |
| Analyze_And_Resolve (N, Restyp); |
| |
| goto Leave; |
| end if; |
| |
| -- Here we have a non-scalar type |
| |
| if Is_Acc then |
| |
| -- If the null exclusion checks are not compatible, need to |
| -- perform further checks. In other words, we cannot have |
| -- Ltyp including null and Typ excluding null. All other cases |
| -- are OK. |
| |
| Check_Null_Exclusion := |
| Can_Never_Be_Null (Typ) and then not Can_Never_Be_Null (Ltyp); |
| Typ := Designated_Type (Typ); |
| end if; |
| |
| if not Is_Constrained (Typ) then |
| Cond := New_Occurrence_Of (Standard_True, Loc); |
| |
| -- For the constrained array case, we have to check the subscripts |
| -- for an exact match if the lengths are non-zero (the lengths |
| -- must match in any case). |
| |
| elsif Is_Array_Type (Typ) then |
| Check_Subscripts : declare |
| function Build_Attribute_Reference |
| (E : Node_Id; |
| Nam : Name_Id; |
| Dim : Nat) return Node_Id; |
| -- Build attribute reference E'Nam (Dim) |
| |
| ------------------------------- |
| -- Build_Attribute_Reference -- |
| ------------------------------- |
| |
| function Build_Attribute_Reference |
| (E : Node_Id; |
| Nam : Name_Id; |
| Dim : Nat) return Node_Id |
| is |
| begin |
| return |
| Make_Attribute_Reference (Loc, |
| Prefix => E, |
| Attribute_Name => Nam, |
| Expressions => New_List ( |
| Make_Integer_Literal (Loc, Dim))); |
| end Build_Attribute_Reference; |
| |
| -- Start of processing for Check_Subscripts |
| |
| begin |
| for J in 1 .. Number_Dimensions (Typ) loop |
| Evolve_And_Then (Cond, |
| Make_Op_Eq (Loc, |
| Left_Opnd => |
| Build_Attribute_Reference |
| (Duplicate_Subexpr_No_Checks (Obj), |
| Name_First, J), |
| Right_Opnd => |
| Build_Attribute_Reference |
| (New_Occurrence_Of (Typ, Loc), Name_First, J))); |
| |
| Evolve_And_Then (Cond, |
| Make_Op_Eq (Loc, |
| Left_Opnd => |
| Build_Attribute_Reference |
| (Duplicate_Subexpr_No_Checks (Obj), |
| Name_Last, J), |
| Right_Opnd => |
| Build_Attribute_Reference |
| (New_Occurrence_Of (Typ, Loc), Name_Last, J))); |
| end loop; |
| end Check_Subscripts; |
| |
| -- These are the cases where constraint checks may be required, |
| -- e.g. records with possible discriminants |
| |
| else |
| -- Expand the test into a series of discriminant comparisons. |
| -- The expression that is built is the negation of the one that |
| -- is used for checking discriminant constraints. |
| |
| Obj := Relocate_Node (Left_Opnd (N)); |
| |
| if Has_Discriminants (Typ) then |
| Cond := Make_Op_Not (Loc, |
| Right_Opnd => Build_Discriminant_Checks (Obj, Typ)); |
| else |
| Cond := New_Occurrence_Of (Standard_True, Loc); |
| end if; |
| end if; |
| |
| if Is_Acc then |
| if Check_Null_Exclusion then |
| Cond := Make_And_Then (Loc, |
| Left_Opnd => |
| Make_Op_Ne (Loc, |
| Left_Opnd => Obj, |
| Right_Opnd => Make_Null (Loc)), |
| Right_Opnd => Cond); |
| else |
| Cond := Make_Or_Else (Loc, |
| Left_Opnd => |
| Make_Op_Eq (Loc, |
| Left_Opnd => Obj, |
| Right_Opnd => Make_Null (Loc)), |
| Right_Opnd => Cond); |
| end if; |
| end if; |
| |
| Rewrite (N, Cond); |
| Analyze_And_Resolve (N, Restyp); |
| |
| -- Ada 2012 (AI05-0149): Handle membership tests applied to an |
| -- expression of an anonymous access type. This can involve an |
| -- accessibility test and a tagged type membership test in the |
| -- case of tagged designated types. |
| |
| if Ada_Version >= Ada_2012 |
| and then Is_Acc |
| and then Ekind (Ltyp) = E_Anonymous_Access_Type |
| then |
| declare |
| Expr_Entity : Entity_Id := Empty; |
| New_N : Node_Id; |
| Param_Level : Node_Id; |
| Type_Level : Node_Id; |
| |
| begin |
| if Is_Entity_Name (Lop) then |
| Expr_Entity := Param_Entity (Lop); |
| |
| if not Present (Expr_Entity) then |
| Expr_Entity := Entity (Lop); |
| end if; |
| end if; |
| |
| -- When restriction No_Dynamic_Accessibility_Checks is in |
| -- effect, expand the membership test to a static value |
| -- since we cannot rely on dynamic levels. |
| |
| if No_Dynamic_Accessibility_Checks_Enabled (Lop) then |
| if Static_Accessibility_Level |
| (Lop, Object_Decl_Level) |
| > Type_Access_Level (Rtyp) |
| then |
| Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); |
| else |
| Rewrite (N, New_Occurrence_Of (Standard_True, Loc)); |
| end if; |
| Analyze_And_Resolve (N, Restyp); |
| |
| -- If a conversion of the anonymous access value to the |
| -- tested type would be illegal, then the result is False. |
| |
| elsif not Valid_Conversion |
| (Lop, Rtyp, Lop, Report_Errs => False) |
| then |
| Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); |
| Analyze_And_Resolve (N, Restyp); |
| |
| -- Apply an accessibility check if the access object has an |
| -- associated access level and when the level of the type is |
| -- less deep than the level of the access parameter. This |
| -- can only occur for access parameters and stand-alone |
| -- objects of an anonymous access type. |
| |
| else |
| Param_Level := Accessibility_Level |
| (Expr_Entity, Dynamic_Level); |
| |
| Type_Level := |
| Make_Integer_Literal (Loc, Type_Access_Level (Rtyp)); |
| |
| -- Return True only if the accessibility level of the |
| -- expression entity is not deeper than the level of |
| -- the tested access type. |
| |
| Rewrite (N, |
| Make_And_Then (Loc, |
| Left_Opnd => Relocate_Node (N), |
| Right_Opnd => Make_Op_Le (Loc, |
| Left_Opnd => Param_Level, |
| Right_Opnd => Type_Level))); |
| |
| Analyze_And_Resolve (N); |
| |
| -- If the designated type is tagged, do tagged membership |
| -- operation. |
| |
| if Is_Tagged_Type (Typ) then |
| |
| -- No expansion will be performed for VM targets, as |
| -- the VM back ends will handle the membership tests |
| -- directly. |
| |
| if Tagged_Type_Expansion then |
| |
| -- Note that we have to pass Original_Node, because |
| -- the membership test might already have been |
| -- rewritten by earlier parts of membership test. |
| |
| Tagged_Membership |
| (Original_Node (N), SCIL_Node, New_N); |
| |
| -- Update decoration of relocated node referenced |
| -- by the SCIL node. |
| |
| if Generate_SCIL and then Present (SCIL_Node) then |
| Set_SCIL_Node (New_N, SCIL_Node); |
| end if; |
| |
| Rewrite (N, |
| Make_And_Then (Loc, |
| Left_Opnd => Relocate_Node (N), |
| Right_Opnd => New_N)); |
| |
| Analyze_And_Resolve (N, Restyp); |
| end if; |
| end if; |
| end if; |
| end; |
| end if; |
| end; |
| end if; |
| |
| -- At this point, we have done the processing required for the basic |
| -- membership test, but not yet dealt with the predicate. |
| |
| <<Leave>> |
| |
| -- If a predicate is present, then we do the predicate test, but we |
| -- most certainly want to omit this if we are within the predicate |
| -- function itself, since otherwise we have an infinite recursion. |
| -- The check should also not be emitted when testing against a range |
| -- (the check is only done when the right operand is a subtype; see |
| -- RM12-4.5.2 (28.1/3-30/3)). |
| |
| Predicate_Check : declare |
| function In_Range_Check return Boolean; |
| -- Within an expanded range check that may raise Constraint_Error do |
| -- not generate a predicate check as well. It is redundant because |
| -- the context will add an explicit predicate check, and it will |
| -- raise the wrong exception if it fails. |
| |
| -------------------- |
| -- In_Range_Check -- |
| -------------------- |
| |
| function In_Range_Check return Boolean is |
| P : Node_Id; |
| begin |
| P := Parent (N); |
| while Present (P) loop |
| if Nkind (P) = N_Raise_Constraint_Error then |
| return True; |
| |
| elsif Nkind (P) in N_Statement_Other_Than_Procedure_Call |
| or else Nkind (P) = N_Procedure_Call_Statement |
| or else Nkind (P) in N_Declaration |
| then |
| return False; |
| end if; |
| |
| P := Parent (P); |
| end loop; |
| |
| return False; |
| end In_Range_Check; |
| |
| -- Local variables |
| |
| PFunc : constant Entity_Id := Predicate_Function (Rtyp); |
| R_Op : Node_Id; |
| |
| -- Start of processing for Predicate_Check |
| |
| begin |
| if Present (PFunc) |
| and then Current_Scope /= PFunc |
| and then Nkind (Rop) /= N_Range |
| then |
| if not In_Range_Check then |
| -- Indicate via Static_Mem parameter that this predicate |
| -- evaluation is for a membership test. |
| R_Op := Make_Predicate_Call (Rtyp, Lop, Static_Mem => True); |
| else |
| R_Op := New_Occurrence_Of (Standard_True, Loc); |
| end if; |
| |
| Rewrite (N, |
| Make_And_Then (Loc, |
| Left_Opnd => Relocate_Node (N), |
| Right_Opnd => R_Op)); |
| |
| -- Analyze new expression, mark left operand as analyzed to |
| -- avoid infinite recursion adding predicate calls. Similarly, |
| -- suppress further range checks on the call. |
| |
| Set_Analyzed (Left_Opnd (N)); |
| Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); |
| |
| -- All done, skip attempt at compile time determination of result |
| |
| return; |
| end if; |
| end Predicate_Check; |
| end Expand_N_In; |
| |
| -------------------------------- |
| -- Expand_N_Indexed_Component -- |
| -------------------------------- |
| |
| procedure Expand_N_Indexed_Component (N : Node_Id) is |
| |
| Wild_Reads_May_Have_Bad_Side_Effects : Boolean |
| renames Validity_Check_Subscripts; |
| -- This Boolean needs to be True if reading from a bad address can |
| -- have a bad side effect (e.g., a segmentation fault that is not |
| -- transformed into a Storage_Error exception, or interactions with |
| -- memory-mapped I/O) that needs to be prevented. This refers to the |
| -- act of reading itself, not to any damage that might be caused later |
| -- by making use of whatever value was read. We assume here that |
| -- Validity_Check_Subscripts meets this requirement, but introduce |
| -- this declaration in order to document this assumption. |
| |
| function Is_Renamed_Variable_Name (N : Node_Id) return Boolean; |
| -- Returns True if the given name occurs as part of the renaming |
| -- of a variable. In this case, the indexing operation should be |
| -- treated as a write, rather than a read, with respect to validity |
| -- checking. This is because the renamed variable can later be |
| -- written to. |
| |
| function Type_Requires_Subscript_Validity_Checks_For_Reads |
| (Typ : Entity_Id) return Boolean; |
| -- If Wild_Reads_May_Have_Bad_Side_Effects is False and we are indexing |
| -- into an array of characters in order to read an element, it is ok |
| -- if an invalid index value goes undetected. But if it is an array of |
| -- pointers or an array of tasks, the consequences of such a read are |
| -- potentially more severe and so we want to detect an invalid index |
| -- value. This function captures that distinction; this is intended to |
| -- be consistent with the "but does not by itself lead to erroneous |
| -- ... execution" rule of RM 13.9.1(11). |
| |
| ------------------------------ |
| -- Is_Renamed_Variable_Name -- |
| ------------------------------ |
| |
| function Is_Renamed_Variable_Name (N : Node_Id) return Boolean is |
| Rover : Node_Id := N; |
| begin |
| if Is_Variable (N) then |
| loop |
| declare |
| Rover_Parent : constant Node_Id := Parent (Rover); |
| begin |
| case Nkind (Rover_Parent) is |
| when N_Object_Renaming_Declaration => |
| return Rover = Name (Rover_Parent); |
| |
| when N_Indexed_Component |
| | N_Slice |
| | N_Selected_Component |
| => |
| exit when Rover /= Prefix (Rover_Parent); |
| Rover := Rover_Parent; |
| |
| -- No need to check for qualified expressions or type |
| -- conversions here, mostly because of the Is_Variable |
| -- test. It is possible to have a view conversion for |
| -- which Is_Variable yields True and which occurs as |
| -- part of an object renaming, but only if the type is |
| -- tagged; in that case this function will not be called. |
| |
| when others => |
| exit; |
| end case; |
| end; |
| end loop; |
| end if; |
| return False; |
| end Is_Renamed_Variable_Name; |
| |
| ------------------------------------------------------- |
| -- Type_Requires_Subscript_Validity_Checks_For_Reads -- |
| ------------------------------------------------------- |
| |
| function Type_Requires_Subscript_Validity_Checks_For_Reads |
| (Typ : Entity_Id) return Boolean |
| is |
| -- a shorter name for recursive calls |
| function Needs_Check (Typ : Entity_Id) return Boolean renames |
| Type_Requires_Subscript_Validity_Checks_For_Reads; |
| begin |
| if Is_Access_Type (Typ) |
| or else Is_Tagged_Type (Typ) |
| or else Is_Concurrent_Type (Typ) |
| or else (Is_Array_Type (Typ) |
| and then Needs_Check (Component_Type (Typ))) |
| or else (Is_Scalar_Type (Typ) |
| and then Has_Aspect (Typ, Aspect_Default_Value)) |
| then |
| return True; |
| end if; |
| |
| if Is_Record_Type (Typ) then |
| declare |
| Comp : Entity_Id := First_Component_Or_Discriminant (Typ); |
| begin |
| while Present (Comp) loop |
| if Needs_Check (Etype (Comp)) then |
| return True; |
| end if; |
| |
| Next_Component_Or_Discriminant (Comp); |
| end loop; |
| end; |
| end if; |
| |
| return False; |
| end Type_Requires_Subscript_Validity_Checks_For_Reads; |
| |
| -- Local constants |
| |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| P : constant Node_Id := Prefix (N); |
| T : constant Entity_Id := Etype (P); |
| |
| -- Start of processing for Expand_N_Indexed_Component |
| |
| begin |
| -- A special optimization, if we have an indexed component that is |
| -- selecting from a slice, then we can eliminate the slice, since, for |
| -- example, x (i .. j)(k) is identical to x(k). The only difference is |
| -- the range check required by the slice. The range check for the slice |
| -- itself has already been generated. The range check for the |
| -- subscripting operation is ensured by converting the subject to |
| -- the subtype of the slice. |
| |
| -- This optimization not only generates better code, avoiding slice |
| -- messing especially in the packed case, but more importantly bypasses |
| -- some problems in handling this peculiar case, for example, the issue |
| -- of dealing specially with object renamings. |
| |
| if Nkind (P) = N_Slice |
| |
| -- This optimization is disabled for CodePeer because it can transform |
| -- an index-check constraint_error into a range-check constraint_error |
| -- and CodePeer cares about that distinction. |
| |
| and then not CodePeer_Mode |
| then |
| Rewrite (N, |
| Make_Indexed_Component (Loc, |
| Prefix => Prefix (P), |
| Expressions => New_List ( |
| Convert_To |
| (Etype (First_Index (Etype (P))), |
| First (Expressions (N)))))); |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end if; |
| |
| -- Ada 2005 (AI-318-02): If the prefix is a call to a build-in-place |
| -- function, then additional actuals must be passed. |
| |
| if Is_Build_In_Place_Function_Call (P) then |
| Make_Build_In_Place_Call_In_Anonymous_Context (P); |
| |
| -- Ada 2005 (AI-318-02): Specialization of the previous case for prefix |
| -- containing build-in-place function calls whose returned object covers |
| -- interface types. |
| |
| elsif Present (Unqual_BIP_Iface_Function_Call (P)) then |
| Make_Build_In_Place_Iface_Call_In_Anonymous_Context (P); |
| end if; |
| |
| -- Generate index and validity checks |
| |
| declare |
| Dims_Checked : Dimension_Set (Dimensions => |
| (if Is_Array_Type (T) |
| then Number_Dimensions (T) |
| else 1)); |
| -- Dims_Checked is used to avoid generating two checks (one in |
| -- Generate_Index_Checks, one in Apply_Subscript_Validity_Checks) |
| -- for the same index value in cases where the index check eliminates |
| -- the need for the validity check. The Is_Array_Type test avoids |
| -- cascading errors. |
| |
| begin |
| Generate_Index_Checks (N, Checks_Generated => Dims_Checked); |
| |
| if Validity_Checks_On |
| and then (Validity_Check_Subscripts |
| or else Wild_Reads_May_Have_Bad_Side_Effects |
| or else Type_Requires_Subscript_Validity_Checks_For_Reads |
| (Typ) |
| or else Is_Renamed_Variable_Name (N)) |
| then |
| if Validity_Check_Subscripts then |
| -- If we index into an array with an uninitialized variable |
| -- and we generate an index check that passes at run time, |
| -- passing that check does not ensure that the variable is |
| -- valid (although it does in the common case where the |
| -- object's subtype matches the index subtype). |
| -- Consider an uninitialized variable with subtype 1 .. 10 |
| -- used to index into an array with bounds 1 .. 20 when the |
| -- value of the uninitialized variable happens to be 15. |
| -- The index check will succeed but the variable is invalid. |
| -- If Validity_Check_Subscripts is True then we need to |
| -- ensure validity, so we adjust Dims_Checked accordingly. |
| Dims_Checked.Elements := (others => False); |
| |
| elsif Is_Array_Type (T) then |
| -- We are only adding extra validity checks here to |
| -- deal with uninitialized variables (but this includes |
| -- assigning one uninitialized variable to another). Other |
| -- ways of producing invalid objects imply erroneousness, so |
| -- the compiler can do whatever it wants for those cases. |
| -- If an index type has the Default_Value aspect specified, |
| -- then we don't have to worry about the possibility of an |
| -- uninitialized variable, so no need for these extra |
| -- validity checks. |
| |
| declare |
| Idx : Node_Id := First_Index (T); |
| begin |
| for No_Check_Needed of Dims_Checked.Elements loop |
| No_Check_Needed := No_Check_Needed |
| or else Has_Aspect (Etype (Idx), Aspect_Default_Value); |
| Next_Index (Idx); |
| end loop; |
| end; |
| end if; |
| |
| Apply_Subscript_Validity_Checks |
| (N, No_Check_Needed => Dims_Checked); |
| end if; |
| end; |
| |
| -- If selecting from an array with atomic components, and atomic sync |
| -- is not suppressed for this array type, set atomic sync flag. |
| |
| if (Has_Atomic_Components (T) |
| and then not Atomic_Synchronization_Disabled (T)) |
| or else (Is_Atomic (Typ) |
| and then not Atomic_Synchronization_Disabled (Typ)) |
| or else (Is_Entity_Name (P) |
| and then Has_Atomic_Components (Entity (P)) |
| and then not Atomic_Synchronization_Disabled (Entity (P))) |
| then |
| Activate_Atomic_Synchronization (N); |
| end if; |
| |
| -- All done if the prefix is not a packed array implemented specially |
| |
| if not (Is_Packed (Etype (Prefix (N))) |
| and then Present (Packed_Array_Impl_Type (Etype (Prefix (N))))) |
| then |
| return; |
| end if; |
| |
| -- For packed arrays that are not bit-packed (i.e. the case of an array |
| -- with one or more index types with a non-contiguous enumeration type), |
| -- we can always use the normal packed element get circuit. |
| |
| if not Is_Bit_Packed_Array (Etype (Prefix (N))) then |
| Expand_Packed_Element_Reference (N); |
| return; |
| end if; |
| |
| -- For a reference to a component of a bit packed array, we convert it |
| -- to a reference to the corresponding Packed_Array_Impl_Type. We only |
| -- want to do this for simple references, and not for: |
| |
| -- Left side of assignment, or prefix of left side of assignment, or |
| -- prefix of the prefix, to handle packed arrays of packed arrays, |
| -- This case is handled in Exp_Ch5.Expand_N_Assignment_Statement |
| |
| -- Renaming objects in renaming associations |
| -- This case is handled when a use of the renamed variable occurs |
| |
| -- Actual parameters for a subprogram call |
| -- This case is handled in Exp_Ch6.Expand_Actuals |
| |
| -- The second expression in a 'Read attribute reference |
| |
| -- The prefix of an address or bit or size attribute reference |
| |
| -- The following circuit detects these exceptions. Note that we need to |
| -- deal with implicit dereferences when climbing up the parent chain, |
| -- with the additional difficulty that the type of parents may have yet |
| -- to be resolved since prefixes are usually resolved first. |
| |
| declare |
| Child : Node_Id := N; |
| Parnt : Node_Id := Parent (N); |
| |
| begin |
| loop |
| if Nkind (Parnt) = N_Unchecked_Expression then |
| null; |
| |
| elsif Nkind (Parnt) = N_Object_Renaming_Declaration then |
| return; |
| |
| elsif Nkind (Parnt) in N_Subprogram_Call |
| or else (Nkind (Parnt) = N_Parameter_Association |
| and then Nkind (Parent (Parnt)) in N_Subprogram_Call) |
| then |
| return; |
| |
| elsif Nkind (Parnt) = N_Attribute_Reference |
| and then Attribute_Name (Parnt) in Name_Address |
| | Name_Bit |
| | Name_Size |
| and then Prefix (Parnt) = Child |
| then |
| return; |
| |
| elsif Nkind (Parnt) = N_Assignment_Statement |
| and then Name (Parnt) = Child |
| then |
| return; |
| |
| -- If the expression is an index of an indexed component, it must |
| -- be expanded regardless of context. |
| |
| elsif Nkind (Parnt) = N_Indexed_Component |
| and then Child /= Prefix (Parnt) |
| then |
| Expand_Packed_Element_Reference (N); |
| return; |
| |
| elsif Nkind (Parent (Parnt)) = N_Assignment_Statement |
| and then Name (Parent (Parnt)) = Parnt |
| then |
| return; |
| |
| elsif Nkind (Parnt) = N_Attribute_Reference |
| and then Attribute_Name (Parnt) = Name_Read |
| and then Next (First (Expressions (Parnt))) = Child |
| then |
| return; |
| |
| elsif Nkind (Parnt) = N_Indexed_Component |
| and then Prefix (Parnt) = Child |
| then |
| null; |
| |
| elsif Nkind (Parnt) = N_Selected_Component |
| and then Prefix (Parnt) = Child |
| and then not (Present (Etype (Selector_Name (Parnt))) |
| and then |
| Is_Access_Type (Etype (Selector_Name (Parnt)))) |
| then |
| null; |
| |
| -- If the parent is a dereference, either implicit or explicit, |
| -- then the packed reference needs to be expanded. |
| |
| else |
| Expand_Packed_Element_Reference (N); |
| return; |
| end if; |
| |
| -- Keep looking up tree for unchecked expression, or if we are the |
| -- prefix of a possible assignment left side. |
| |
| Child := Parnt; |
| Parnt := Parent (Child); |
| end loop; |
| end; |
| end Expand_N_Indexed_Component; |
| |
| --------------------- |
| -- Expand_N_Not_In -- |
| --------------------- |
| |
| -- Replace a not in b by not (a in b) so that the expansions for (a in b) |
| -- can be done. This avoids needing to duplicate this expansion code. |
| |
| procedure Expand_N_Not_In (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| Cfs : constant Boolean := Comes_From_Source (N); |
| |
| begin |
| Rewrite (N, |
| Make_Op_Not (Loc, |
| Right_Opnd => |
| Make_In (Loc, |
| Left_Opnd => Left_Opnd (N), |
| Right_Opnd => Right_Opnd (N)))); |
| |
| -- If this is a set membership, preserve list of alternatives |
| |
| Set_Alternatives (Right_Opnd (N), Alternatives (Original_Node (N))); |
| |
| -- We want this to appear as coming from source if original does (see |
| -- transformations in Expand_N_In). |
| |
| Set_Comes_From_Source (N, Cfs); |
| Set_Comes_From_Source (Right_Opnd (N), Cfs); |
| |
| -- Now analyze transformed node |
| |
| Analyze_And_Resolve (N, Typ); |
| end Expand_N_Not_In; |
| |
| ------------------- |
| -- Expand_N_Null -- |
| ------------------- |
| |
| -- The only replacement required is for the case of a null of a type that |
| -- is an access to protected subprogram, or a subtype thereof. We represent |
| -- such access values as a record, and so we must replace the occurrence of |
| -- null by the equivalent record (with a null address and a null pointer in |
| -- it), so that the back end creates the proper value. |
| |
| procedure Expand_N_Null (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Base_Type (Etype (N)); |
| Agg : Node_Id; |
| |
| begin |
| if Is_Access_Protected_Subprogram_Type (Typ) then |
| Agg := |
| Make_Aggregate (Loc, |
| Expressions => New_List ( |
| New_Occurrence_Of (RTE (RE_Null_Address), Loc), |
| Make_Null (Loc))); |
| |
| Rewrite (N, Agg); |
| Analyze_And_Resolve (N, Equivalent_Type (Typ)); |
| |
| -- For subsequent semantic analysis, the node must retain its type. |
| -- Gigi in any case replaces this type by the corresponding record |
| -- type before processing the node. |
| |
| Set_Etype (N, Typ); |
| end if; |
| |
| exception |
| when RE_Not_Available => |
| return; |
| end Expand_N_Null; |
| |
| --------------------- |
| -- Expand_N_Op_Abs -- |
| --------------------- |
| |
| procedure Expand_N_Op_Abs (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Expr : constant Node_Id := Right_Opnd (N); |
| Typ : constant Entity_Id := Etype (N); |
| |
| begin |
| Unary_Op_Validity_Checks (N); |
| |
| -- Check for MINIMIZED/ELIMINATED overflow mode |
| |
| if Minimized_Eliminated_Overflow_Check (N) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- Try to narrow the operation |
| |
| if Typ = Universal_Integer then |
| Narrow_Large_Operation (N); |
| |
| if Nkind (N) /= N_Op_Abs then |
| return; |
| end if; |
| end if; |
| |
| -- Deal with software overflow checking |
| |
| if Is_Signed_Integer_Type (Typ) |
| and then Do_Overflow_Check (N) |
| then |
| -- The only case to worry about is when the argument is equal to the |
| -- largest negative number, so what we do is to insert the check: |
| |
| -- [constraint_error when Expr = typ'Base'First] |
| |
| -- with the usual Duplicate_Subexpr use coding for expr |
| |
| Insert_Action (N, |
| Make_Raise_Constraint_Error (Loc, |
| Condition => |
| Make_Op_Eq (Loc, |
| Left_Opnd => Duplicate_Subexpr (Expr), |
| Right_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of (Base_Type (Etype (Expr)), Loc), |
| Attribute_Name => Name_First)), |
| Reason => CE_Overflow_Check_Failed)); |
| |
| Set_Do_Overflow_Check (N, False); |
| end if; |
| end Expand_N_Op_Abs; |
| |
| --------------------- |
| -- Expand_N_Op_Add -- |
| --------------------- |
| |
| procedure Expand_N_Op_Add (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- Check for MINIMIZED/ELIMINATED overflow mode |
| |
| if Minimized_Eliminated_Overflow_Check (N) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- N + 0 = 0 + N = N for integer types |
| |
| if Is_Integer_Type (Typ) then |
| if Compile_Time_Known_Value (Right_Opnd (N)) |
| and then Expr_Value (Right_Opnd (N)) = Uint_0 |
| then |
| Rewrite (N, Left_Opnd (N)); |
| return; |
| |
| elsif Compile_Time_Known_Value (Left_Opnd (N)) |
| and then Expr_Value (Left_Opnd (N)) = Uint_0 |
| then |
| Rewrite (N, Right_Opnd (N)); |
| return; |
| end if; |
| end if; |
| |
| -- Try to narrow the operation |
| |
| if Typ = Universal_Integer then |
| Narrow_Large_Operation (N); |
| |
| if Nkind (N) /= N_Op_Add then |
| return; |
| end if; |
| end if; |
| |
| -- Arithmetic overflow checks for signed integer/fixed point types |
| |
| if Is_Signed_Integer_Type (Typ) or else Is_Fixed_Point_Type (Typ) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- Overflow checks for floating-point if -gnateF mode active |
| |
| Check_Float_Op_Overflow (N); |
| |
| Expand_Nonbinary_Modular_Op (N); |
| end Expand_N_Op_Add; |
| |
| --------------------- |
| -- Expand_N_Op_And -- |
| --------------------- |
| |
| procedure Expand_N_Op_And (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| if Is_Array_Type (Etype (N)) then |
| Expand_Boolean_Operator (N); |
| |
| elsif Is_Boolean_Type (Etype (N)) then |
| Adjust_Condition (Left_Opnd (N)); |
| Adjust_Condition (Right_Opnd (N)); |
| Set_Etype (N, Standard_Boolean); |
| Adjust_Result_Type (N, Typ); |
| |
| elsif Is_Intrinsic_Subprogram (Entity (N)) then |
| Expand_Intrinsic_Call (N, Entity (N)); |
| end if; |
| |
| Expand_Nonbinary_Modular_Op (N); |
| end Expand_N_Op_And; |
| |
| ------------------------ |
| -- Expand_N_Op_Concat -- |
| ------------------------ |
| |
| procedure Expand_N_Op_Concat (N : Node_Id) is |
| Opnds : List_Id; |
| -- List of operands to be concatenated |
| |
| Cnode : Node_Id; |
| -- Node which is to be replaced by the result of concatenating the nodes |
| -- in the list Opnds. |
| |
| begin |
| -- Ensure validity of both operands |
| |
| Binary_Op_Validity_Checks (N); |
| |
| -- If we are the left operand of a concatenation higher up the tree, |
| -- then do nothing for now, since we want to deal with a series of |
| -- concatenations as a unit. |
| |
| if Nkind (Parent (N)) = N_Op_Concat |
| and then N = Left_Opnd (Parent (N)) |
| then |
| return; |
| end if; |
| |
| -- We get here with a concatenation whose left operand may be a |
| -- concatenation itself with a consistent type. We need to process |
| -- these concatenation operands from left to right, which means |
| -- from the deepest node in the tree to the highest node. |
| |
| Cnode := N; |
| while Nkind (Left_Opnd (Cnode)) = N_Op_Concat loop |
| Cnode := Left_Opnd (Cnode); |
| end loop; |
| |
| -- Now Cnode is the deepest concatenation, and its parents are the |
| -- concatenation nodes above, so now we process bottom up, doing the |
| -- operands. |
| |
| -- The outer loop runs more than once if more than one concatenation |
| -- type is involved. |
| |
| Outer : loop |
| Opnds := New_List (Left_Opnd (Cnode), Right_Opnd (Cnode)); |
| Set_Parent (Opnds, N); |
| |
| -- The inner loop gathers concatenation operands |
| |
| Inner : while Cnode /= N |
| and then Base_Type (Etype (Cnode)) = |
| Base_Type (Etype (Parent (Cnode))) |
| loop |
| Cnode := Parent (Cnode); |
| Append (Right_Opnd (Cnode), Opnds); |
| end loop Inner; |
| |
| -- Note: The following code is a temporary workaround for N731-034 |
| -- and N829-028 and will be kept until the general issue of internal |
| -- symbol serialization is addressed. The workaround is kept under a |
| -- debug switch to avoid permiating into the general case. |
| |
| -- Wrap the node to concatenate into an expression actions node to |
| -- keep it nicely packaged. This is useful in the case of an assert |
| -- pragma with a concatenation where we want to be able to delete |
| -- the concatenation and all its expansion stuff. |
| |
| if Debug_Flag_Dot_H then |
| declare |
| Cnod : constant Node_Id := New_Copy_Tree (Cnode); |
| Typ : constant Entity_Id := Base_Type (Etype (Cnode)); |
| |
| begin |
| -- Note: use Rewrite rather than Replace here, so that for |
| -- example Why_Not_Static can find the original concatenation |
| -- node OK! |
| |
| Rewrite (Cnode, |
| Make_Expression_With_Actions (Sloc (Cnode), |
| Actions => New_List (Make_Null_Statement (Sloc (Cnode))), |
| Expression => Cnod)); |
| |
| Expand_Concatenate (Cnod, Opnds); |
| Analyze_And_Resolve (Cnode, Typ); |
| end; |
| |
| -- Default case |
| |
| else |
| Expand_Concatenate (Cnode, Opnds); |
| end if; |
| |
| exit Outer when Cnode = N; |
| Cnode := Parent (Cnode); |
| end loop Outer; |
| end Expand_N_Op_Concat; |
| |
| ------------------------ |
| -- Expand_N_Op_Divide -- |
| ------------------------ |
| |
| procedure Expand_N_Op_Divide (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Lopnd : constant Node_Id := Left_Opnd (N); |
| Ropnd : constant Node_Id := Right_Opnd (N); |
| Ltyp : constant Entity_Id := Etype (Lopnd); |
| Rtyp : constant Entity_Id := Etype (Ropnd); |
| Typ : Entity_Id := Etype (N); |
| Rknow : constant Boolean := Is_Integer_Type (Typ) |
| and then |
| Compile_Time_Known_Value (Ropnd); |
| Rval : Uint; |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- Check for MINIMIZED/ELIMINATED overflow mode |
| |
| if Minimized_Eliminated_Overflow_Check (N) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- Otherwise proceed with expansion of division |
| |
| if Rknow then |
| Rval := Expr_Value (Ropnd); |
| end if; |
| |
| -- N / 1 = N for integer types |
| |
| if Rknow and then Rval = Uint_1 then |
| Rewrite (N, Lopnd); |
| return; |
| end if; |
| |
| -- Try to narrow the operation |
| |
| if Typ = Universal_Integer then |
| Narrow_Large_Operation (N); |
| |
| if Nkind (N) /= N_Op_Divide then |
| return; |
| end if; |
| end if; |
| |
| -- Convert x / 2 ** y to Shift_Right (x, y). Note that the fact that |
| -- Is_Power_Of_2_For_Shift is set means that we know that our left |
| -- operand is an unsigned integer, as required for this to work. |
| |
| if Nkind (Ropnd) = N_Op_Expon |
| and then Is_Power_Of_2_For_Shift (Ropnd) |
| |
| -- We cannot do this transformation in configurable run time mode if we |
| -- have 64-bit integers and long shifts are not available. |
| |
| and then (Esize (Ltyp) <= 32 or else Support_Long_Shifts_On_Target) |
| then |
| Rewrite (N, |
| Make_Op_Shift_Right (Loc, |
| Left_Opnd => Lopnd, |
| Right_Opnd => |
| Convert_To (Standard_Natural, Right_Opnd (Ropnd)))); |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end if; |
| |
| -- Do required fixup of universal fixed operation |
| |
| if Typ = Universal_Fixed then |
| Fixup_Universal_Fixed_Operation (N); |
| Typ := Etype (N); |
| end if; |
| |
| -- Divisions with fixed-point results |
| |
| if Is_Fixed_Point_Type (Typ) then |
| |
| if Is_Integer_Type (Rtyp) then |
| Expand_Divide_Fixed_By_Integer_Giving_Fixed (N); |
| else |
| Expand_Divide_Fixed_By_Fixed_Giving_Fixed (N); |
| end if; |
| |
| -- Deal with divide-by-zero check if back end cannot handle them |
| -- and the flag is set indicating that we need such a check. Note |
| -- that we don't need to bother here with the case of mixed-mode |
| -- (Right operand an integer type), since these will be rewritten |
| -- with conversions to a divide with a fixed-point right operand. |
| |
| if Nkind (N) = N_Op_Divide |
| and then Do_Division_Check (N) |
| and then not Backend_Divide_Checks_On_Target |
| and then not Is_Integer_Type (Rtyp) |
| then |
| Set_Do_Division_Check (N, False); |
| Insert_Action (N, |
| Make_Raise_Constraint_Error (Loc, |
| Condition => |
| Make_Op_Eq (Loc, |
| Left_Opnd => Duplicate_Subexpr_Move_Checks (Ropnd), |
| Right_Opnd => Make_Real_Literal (Loc, Ureal_0)), |
| Reason => CE_Divide_By_Zero)); |
| end if; |
| |
| -- Other cases of division of fixed-point operands |
| |
| elsif Is_Fixed_Point_Type (Ltyp) or else Is_Fixed_Point_Type (Rtyp) then |
| if Is_Integer_Type (Typ) then |
| Expand_Divide_Fixed_By_Fixed_Giving_Integer (N); |
| else |
| pragma Assert (Is_Floating_Point_Type (Typ)); |
| Expand_Divide_Fixed_By_Fixed_Giving_Float (N); |
| end if; |
| |
| -- Mixed-mode operations can appear in a non-static universal context, |
| -- in which case the integer argument must be converted explicitly. |
| |
| elsif Typ = Universal_Real and then Is_Integer_Type (Rtyp) then |
| Rewrite (Ropnd, |
| Convert_To (Universal_Real, Relocate_Node (Ropnd))); |
| |
| Analyze_And_Resolve (Ropnd, Universal_Real); |
| |
| elsif Typ = Universal_Real and then Is_Integer_Type (Ltyp) then |
| Rewrite (Lopnd, |
| Convert_To (Universal_Real, Relocate_Node (Lopnd))); |
| |
| Analyze_And_Resolve (Lopnd, Universal_Real); |
| |
| -- Non-fixed point cases, do integer zero divide and overflow checks |
| |
| elsif Is_Integer_Type (Typ) then |
| Apply_Divide_Checks (N); |
| end if; |
| |
| -- Overflow checks for floating-point if -gnateF mode active |
| |
| Check_Float_Op_Overflow (N); |
| |
| Expand_Nonbinary_Modular_Op (N); |
| end Expand_N_Op_Divide; |
| |
| -------------------- |
| -- Expand_N_Op_Eq -- |
| -------------------- |
| |
| procedure Expand_N_Op_Eq (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| Lhs : constant Node_Id := Left_Opnd (N); |
| Rhs : constant Node_Id := Right_Opnd (N); |
| Bodies : constant List_Id := New_List; |
| A_Typ : constant Entity_Id := Etype (Lhs); |
| |
| procedure Build_Equality_Call (Eq : Entity_Id); |
| -- If a constructed equality exists for the type or for its parent, |
| -- build and analyze call, adding conversions if the operation is |
| -- inherited. |
| |
| function Find_Equality (Prims : Elist_Id) return Entity_Id; |
| -- Find a primitive equality function within primitive operation list |
| -- Prims. |
| |
| function Has_Unconstrained_UU_Component (Typ : Entity_Id) return Boolean; |
| -- Determines whether a type has a subcomponent of an unconstrained |
| -- Unchecked_Union subtype. Typ is a record type. |
| |
| ------------------------- |
| -- Build_Equality_Call -- |
| ------------------------- |
| |
| procedure Build_Equality_Call (Eq : Entity_Id) is |
| Op_Type : constant Entity_Id := Etype (First_Formal (Eq)); |
| L_Exp : Node_Id := Relocate_Node (Lhs); |
| R_Exp : Node_Id := Relocate_Node (Rhs); |
| |
| begin |
| -- Adjust operands if necessary to comparison type |
| |
| if Base_Type (Op_Type) /= Base_Type (A_Typ) |
| and then not Is_Class_Wide_Type (A_Typ) |
| then |
| L_Exp := OK_Convert_To (Op_Type, L_Exp); |
| R_Exp := OK_Convert_To (Op_Type, R_Exp); |
| end if; |
| |
| -- If we have an Unchecked_Union, we need to add the inferred |
| -- discriminant values as actuals in the function call. At this |
| -- point, the expansion has determined that both operands have |
| -- inferable discriminants. |
| |
| if Is_Unchecked_Union (Op_Type) then |
| declare |
| Lhs_Type : constant Entity_Id := Etype (L_Exp); |
| Rhs_Type : constant Entity_Id := Etype (R_Exp); |
| |
| Lhs_Discr_Vals : Elist_Id; |
| -- List of inferred discriminant values for left operand. |
| |
| Rhs_Discr_Vals : Elist_Id; |
| -- List of inferred discriminant values for right operand. |
| |
| Discr : Entity_Id; |
| |
| begin |
| Lhs_Discr_Vals := New_Elmt_List; |
| Rhs_Discr_Vals := New_Elmt_List; |
| |
| -- Per-object constrained selected components require special |
| -- attention. If the enclosing scope of the component is an |
| -- Unchecked_Union, we cannot reference its discriminants |
| -- directly. This is why we use the extra parameters of the |
| -- equality function of the enclosing Unchecked_Union. |
| |
| -- type UU_Type (Discr : Integer := 0) is |
| -- . . . |
| -- end record; |
| -- pragma Unchecked_Union (UU_Type); |
| |
| -- 1. Unchecked_Union enclosing record: |
| |
| -- type Enclosing_UU_Type (Discr : Integer := 0) is record |
| -- . . . |
| -- Comp : UU_Type (Discr); |
| -- . . . |
| -- end Enclosing_UU_Type; |
| -- pragma Unchecked_Union (Enclosing_UU_Type); |
| |
| -- Obj1 : Enclosing_UU_Type; |
| -- Obj2 : Enclosing_UU_Type (1); |
| |
| -- [. . .] Obj1 = Obj2 [. . .] |
| |
| -- Generated code: |
| |
| -- if not (uu_typeEQ (obj1.comp, obj2.comp, a, b)) then |
| |
| -- A and B are the formal parameters of the equality function |
| -- of Enclosing_UU_Type. The function always has two extra |
| -- formals to capture the inferred discriminant values for |
| -- each discriminant of the type. |
| |
| -- 2. Non-Unchecked_Union enclosing record: |
| |
| -- type |
| -- Enclosing_Non_UU_Type (Discr : Integer := 0) |
| -- is record |
| -- . . . |
| -- Comp : UU_Type (Discr); |
| -- . . . |
| -- end Enclosing_Non_UU_Type; |
| |
| -- Obj1 : Enclosing_Non_UU_Type; |
| -- Obj2 : Enclosing_Non_UU_Type (1); |
| |
| -- ... Obj1 = Obj2 ... |
| |
| -- Generated code: |
| |
| -- if not (uu_typeEQ (obj1.comp, obj2.comp, |
| -- obj1.discr, obj2.discr)) then |
| |
| -- In this case we can directly reference the discriminants of |
| -- the enclosing record. |
| |
| -- Process left operand of equality |
| |
| if Nkind (Lhs) = N_Selected_Component |
| and then |
| Has_Per_Object_Constraint (Entity (Selector_Name (Lhs))) |
| then |
| -- If enclosing record is an Unchecked_Union, use formals |
| -- corresponding to each discriminant. The name of the |
| -- formal is that of the discriminant, with added suffix, |
| -- see Exp_Ch3.Build_Record_Equality for details. |
| |
| if Is_Unchecked_Union (Scope (Entity (Selector_Name (Lhs)))) |
| then |
| Discr := |
| First_Discriminant |
| (Scope (Entity (Selector_Name (Lhs)))); |
| while Present (Discr) loop |
| Append_Elmt |
| (Make_Identifier (Loc, |
| Chars => New_External_Name (Chars (Discr), 'A')), |
| To => Lhs_Discr_Vals); |
| Next_Discriminant (Discr); |
| end loop; |
| |
| -- If enclosing record is of a non-Unchecked_Union type, it |
| -- is possible to reference its discriminants directly. |
| |
| else |
| Discr := First_Discriminant (Lhs_Type); |
| while Present (Discr) loop |
| Append_Elmt |
| (Make_Selected_Component (Loc, |
| Prefix => Prefix (Lhs), |
| Selector_Name => |
| New_Copy |
| (Get_Discriminant_Value (Discr, |
| Lhs_Type, |
| Stored_Constraint (Lhs_Type)))), |
| To => Lhs_Discr_Vals); |
| Next_Discriminant (Discr); |
| end loop; |
| end if; |
| |
| -- Otherwise operand is on object with a constrained type. |
| -- Infer the discriminant values from the constraint. |
| |
| else |
| Discr := First_Discriminant (Lhs_Type); |
| while Present (Discr) loop |
| Append_Elmt |
| (New_Copy |
| (Get_Discriminant_Value (Discr, |
| Lhs_Type, |
| Stored_Constraint (Lhs_Type))), |
| To => Lhs_Discr_Vals); |
| Next_Discriminant (Discr); |
| end loop; |
| end if; |
| |
| -- Similar processing for right operand of equality |
| |
| if Nkind (Rhs) = N_Selected_Component |
| and then |
| Has_Per_Object_Constraint (Entity (Selector_Name (Rhs))) |
| then |
| if Is_Unchecked_Union |
| (Scope (Entity (Selector_Name (Rhs)))) |
| then |
| Discr := |
| First_Discriminant |
| (Scope (Entity (Selector_Name (Rhs)))); |
| while Present (Discr) loop |
| Append_Elmt |
| (Make_Identifier (Loc, |
| Chars => New_External_Name (Chars (Discr), 'B')), |
| To => Rhs_Discr_Vals); |
| Next_Discriminant (Discr); |
| end loop; |
| |
| else |
| Discr := First_Discriminant (Rhs_Type); |
| while Present (Discr) loop |
| Append_Elmt |
| (Make_Selected_Component (Loc, |
| Prefix => Prefix (Rhs), |
| Selector_Name => |
| New_Copy (Get_Discriminant_Value |
| (Discr, |
| Rhs_Type, |
| Stored_Constraint (Rhs_Type)))), |
| To => Rhs_Discr_Vals); |
| Next_Discriminant (Discr); |
| end loop; |
| end if; |
| |
| else |
| Discr := First_Discriminant (Rhs_Type); |
| while Present (Discr) loop |
| Append_Elmt |
| (New_Copy (Get_Discriminant_Value |
| (Discr, |
| Rhs_Type, |
| Stored_Constraint (Rhs_Type))), |
| To => Rhs_Discr_Vals); |
| Next_Discriminant (Discr); |
| end loop; |
| end if; |
| |
| -- Now merge the list of discriminant values so that values |
| -- of corresponding discriminants are adjacent. |
| |
| declare |
| Params : List_Id; |
| L_Elmt : Elmt_Id; |
| R_Elmt : Elmt_Id; |
| |
| begin |
| Params := New_List (L_Exp, R_Exp); |
| L_Elmt := First_Elmt (Lhs_Discr_Vals); |
| R_Elmt := First_Elmt (Rhs_Discr_Vals); |
| while Present (L_Elmt) loop |
| Append_To (Params, Node (L_Elmt)); |
| Append_To (Params, Node (R_Elmt)); |
| Next_Elmt (L_Elmt); |
| Next_Elmt (R_Elmt); |
| end loop; |
| |
| Rewrite (N, |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Eq, Loc), |
| Parameter_Associations => Params)); |
| end; |
| end; |
| |
| -- Normal case, not an unchecked union |
| |
| else |
| Rewrite (N, |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Eq, Loc), |
| Parameter_Associations => New_List (L_Exp, R_Exp))); |
| end if; |
| |
| Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); |
| end Build_Equality_Call; |
| |
| ------------------- |
| -- Find_Equality -- |
| ------------------- |
| |
| function Find_Equality (Prims : Elist_Id) return Entity_Id is |
| function Find_Aliased_Equality (Prim : Entity_Id) return Entity_Id; |
| -- Find an equality in a possible alias chain starting from primitive |
| -- operation Prim. |
| |
| --------------------------- |
| -- Find_Aliased_Equality -- |
| --------------------------- |
| |
| function Find_Aliased_Equality (Prim : Entity_Id) return Entity_Id is |
| Candid : Entity_Id; |
| |
| begin |
| -- Inspect each candidate in the alias chain, checking whether it |
| -- denotes an equality. |
| |
| Candid := Prim; |
| while Present (Candid) loop |
| if Is_User_Defined_Equality (Candid) then |
| return Candid; |
| end if; |
| |
| Candid := Alias (Candid); |
| end loop; |
| |
| return Empty; |
| end Find_Aliased_Equality; |
| |
| -- Local variables |
| |
| Eq_Prim : Entity_Id; |
| Prim_Elmt : Elmt_Id; |
| |
| -- Start of processing for Find_Equality |
| |
| begin |
| -- Assume that the tagged type lacks an equality |
| |
| Eq_Prim := Empty; |
| |
| -- Inspect the list of primitives looking for a suitable equality |
| -- within a possible chain of aliases. |
| |
| Prim_Elmt := First_Elmt (Prims); |
| while Present (Prim_Elmt) and then No (Eq_Prim) loop |
| Eq_Prim := Find_Aliased_Equality (Node (Prim_Elmt)); |
| |
| Next_Elmt (Prim_Elmt); |
| end loop; |
| |
| -- A tagged type should always have an equality |
| |
| pragma Assert (Present (Eq_Prim)); |
| |
| return Eq_Prim; |
| end Find_Equality; |
| |
| ------------------------------------ |
| -- Has_Unconstrained_UU_Component -- |
| ------------------------------------ |
| |
| function Has_Unconstrained_UU_Component |
| (Typ : Entity_Id) return Boolean |
| is |
| function Unconstrained_UU_In_Component_Declaration |
| (N : Node_Id) return Boolean; |
| |
| function Unconstrained_UU_In_Component_Items |
| (L : List_Id) return Boolean; |
| |
| function Unconstrained_UU_In_Component_List |
| (N : Node_Id) return Boolean; |
| |
| function Unconstrained_UU_In_Variant_Part |
| (N : Node_Id) return Boolean; |
| -- A family of routines that determine whether a particular construct |
| -- of a record type definition contains a subcomponent of an |
| -- unchecked union type whose nominal subtype is unconstrained. |
| -- |
| -- Individual routines correspond to the production rules of the Ada |
| -- grammar, as described in the Ada RM (P). |
| |
| ----------------------------------------------- |
| -- Unconstrained_UU_In_Component_Declaration -- |
| ----------------------------------------------- |
| |
| function Unconstrained_UU_In_Component_Declaration |
| (N : Node_Id) return Boolean |
| is |
| pragma Assert (Nkind (N) = N_Component_Declaration); |
| |
| Sindic : constant Node_Id := |
| Subtype_Indication (Component_Definition (N)); |
| begin |
| -- If the component declaration includes a subtype indication |
| -- it is not an unchecked_union. Otherwise verify that it carries |
| -- the Unchecked_Union flag and is either a record or a private |
| -- type. A Record_Subtype declared elsewhere does not qualify, |
| -- even if its parent type carries the flag. |
| |
| return Nkind (Sindic) in N_Expanded_Name | N_Identifier |
| and then Is_Unchecked_Union (Base_Type (Etype (Sindic))) |
| and then (Ekind (Entity (Sindic)) in |
| E_Private_Type | E_Record_Type); |
| end Unconstrained_UU_In_Component_Declaration; |
| |
| ----------------------------------------- |
| -- Unconstrained_UU_In_Component_Items -- |
| ----------------------------------------- |
| |
| function Unconstrained_UU_In_Component_Items |
| (L : List_Id) return Boolean |
| is |
| N : Node_Id := First (L); |
| begin |
| while Present (N) loop |
| if Nkind (N) = N_Component_Declaration |
| and then Unconstrained_UU_In_Component_Declaration (N) |
| then |
| return True; |
| end if; |
| |
| Next (N); |
| end loop; |
| |
| return False; |
| end Unconstrained_UU_In_Component_Items; |
| |
| ---------------------------------------- |
| -- Unconstrained_UU_In_Component_List -- |
| ---------------------------------------- |
| |
| function Unconstrained_UU_In_Component_List |
| (N : Node_Id) return Boolean |
| is |
| pragma Assert (Nkind (N) = N_Component_List); |
| |
| Optional_Variant_Part : Node_Id; |
| begin |
| if Unconstrained_UU_In_Component_Items (Component_Items (N)) then |
| return True; |
| end if; |
| |
| Optional_Variant_Part := Variant_Part (N); |
| |
| return |
| Present (Optional_Variant_Part) |
| and then |
| Unconstrained_UU_In_Variant_Part (Optional_Variant_Part); |
| end Unconstrained_UU_In_Component_List; |
| |
| -------------------------------------- |
| -- Unconstrained_UU_In_Variant_Part -- |
| -------------------------------------- |
| |
| function Unconstrained_UU_In_Variant_Part |
| (N : Node_Id) return Boolean |
| is |
| pragma Assert (Nkind (N) = N_Variant_Part); |
| |
| Variant : Node_Id := First (Variants (N)); |
| begin |
| loop |
| if Unconstrained_UU_In_Component_List (Component_List (Variant)) |
| then |
| return True; |
| end if; |
| |
| Next (Variant); |
| exit when No (Variant); |
| end loop; |
| |
| return False; |
| end Unconstrained_UU_In_Variant_Part; |
| |
| Typ_Def : constant Node_Id := |
| Type_Definition (Declaration_Node (Base_Type (Typ))); |
| |
| Optional_Component_List : constant Node_Id := |
| Component_List (Typ_Def); |
| |
| -- Start of processing for Has_Unconstrained_UU_Component |
| |
| begin |
| return Present (Optional_Component_List) |
| and then |
| Unconstrained_UU_In_Component_List (Optional_Component_List); |
| end Has_Unconstrained_UU_Component; |
| |
| -- Local variables |
| |
| Typl : Entity_Id; |
| |
| -- Start of processing for Expand_N_Op_Eq |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- Deal with private types |
| |
| Typl := Underlying_Type (A_Typ); |
| |
| -- It may happen in error situations that the underlying type is not |
| -- set. The error will be detected later, here we just defend the |
| -- expander code. |
| |
| if No (Typl) then |
| return; |
| end if; |
| |
| -- Now get the implementation base type (note that plain Base_Type here |
| -- might lead us back to the private type, which is not what we want!) |
| |
| Typl := Implementation_Base_Type (Typl); |
| |
| -- Equality between variant records results in a call to a routine |
| -- that has conditional tests of the discriminant value(s), and hence |
| -- violates the No_Implicit_Conditionals restriction. |
| |
| if Has_Variant_Part (Typl) then |
| declare |
| Msg : Boolean; |
| |
| begin |
| Check_Restriction (Msg, No_Implicit_Conditionals, N); |
| |
| if Msg then |
| Error_Msg_N |
| ("\comparison of variant records tests discriminants", N); |
| return; |
| end if; |
| end; |
| end if; |
| |
| -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that |
| -- means we no longer have a comparison operation, we are all done. |
| |
| if Minimized_Eliminated_Overflow_Check (Left_Opnd (N)) then |
| Expand_Compare_Minimize_Eliminate_Overflow (N); |
| end if; |
| |
| if Nkind (N) /= N_Op_Eq then |
| return; |
| end if; |
| |
| -- Boolean types (requiring handling of non-standard case) |
| |
| if Is_Boolean_Type (Typl) then |
| Adjust_Condition (Left_Opnd (N)); |
| Adjust_Condition (Right_Opnd (N)); |
| Set_Etype (N, Standard_Boolean); |
| Adjust_Result_Type (N, Typ); |
| |
| -- Array types |
| |
| elsif Is_Array_Type (Typl) then |
| |
| -- If we are doing full validity checking, and it is possible for the |
| -- array elements to be invalid then expand out array comparisons to |
| -- make sure that we check the array elements. |
| |
| if Validity_Check_Operands |
| and then not Is_Known_Valid (Component_Type (Typl)) |
| then |
| declare |
| Save_Force_Validity_Checks : constant Boolean := |
| Force_Validity_Checks; |
| begin |
| Force_Validity_Checks := True; |
| Rewrite (N, |
| Expand_Array_Equality |
| (N, |
| Relocate_Node (Lhs), |
| Relocate_Node (Rhs), |
| Bodies, |
| Typl)); |
| Insert_Actions (N, Bodies); |
| Analyze_And_Resolve (N, Standard_Boolean); |
| Force_Validity_Checks := Save_Force_Validity_Checks; |
| end; |
| |
| -- Packed case where both operands are known aligned |
| |
| elsif Is_Bit_Packed_Array (Typl) |
| and then not Is_Possibly_Unaligned_Object (Lhs) |
| and then not Is_Possibly_Unaligned_Object (Rhs) |
| then |
| Expand_Packed_Eq (N); |
| |
| -- Where the component type is elementary we can use a block bit |
| -- comparison (if supported on the target) exception in the case |
| -- of floating-point (negative zero issues require element by |
| -- element comparison), and full access types (where we must be sure |
| -- to load elements independently) and possibly unaligned arrays. |
| |
| elsif Is_Elementary_Type (Component_Type (Typl)) |
| and then not Is_Floating_Point_Type (Component_Type (Typl)) |
| and then not Is_Full_Access (Component_Type (Typl)) |
| and then not Is_Possibly_Unaligned_Object (Lhs) |
| and then not Is_Possibly_Unaligned_Slice (Lhs) |
| and then not Is_Possibly_Unaligned_Object (Rhs) |
| and then not Is_Possibly_Unaligned_Slice (Rhs) |
| and then Support_Composite_Compare_On_Target |
| then |
| null; |
| |
| -- For composite and floating-point cases, expand equality loop to |
| -- make sure of using proper comparisons for tagged types, and |
| -- correctly handling the floating-point case. |
| |
| else |
| Rewrite (N, |
| Expand_Array_Equality |
| (N, |
| Relocate_Node (Lhs), |
| Relocate_Node (Rhs), |
| Bodies, |
| Typl)); |
| Insert_Actions (N, Bodies, Suppress => All_Checks); |
| Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); |
| end if; |
| |
| -- Record Types |
| |
| elsif Is_Record_Type (Typl) then |
| |
| -- For tagged types, use the primitive "=" |
| |
| if Is_Tagged_Type (Typl) then |
| |
| -- No need to do anything else compiling under restriction |
| -- No_Dispatching_Calls. During the semantic analysis we |
| -- already notified such violation. |
| |
| if Restriction_Active (No_Dispatching_Calls) then |
| return; |
| end if; |
| |
| -- If this is an untagged private type completed with a derivation |
| -- of an untagged private type whose full view is a tagged type, |
| -- we use the primitive operations of the private type (since it |
| -- does not have a full view, and also because its equality |
| -- primitive may have been overridden in its untagged full view). |
| |
| if Inherits_From_Tagged_Full_View (A_Typ) then |
| Build_Equality_Call |
| (Find_Equality (Collect_Primitive_Operations (A_Typ))); |
| |
| -- Find the type's predefined equality or an overriding |
| -- user-defined equality. The reason for not simply calling |
| -- Find_Prim_Op here is that there may be a user-defined |
| -- overloaded equality op that precedes the equality that we |
| -- want, so we have to explicitly search (e.g., there could be |
| -- an equality with two different parameter types). |
| |
| else |
| if Is_Class_Wide_Type (Typl) then |
| Typl := Find_Specific_Type (Typl); |
| end if; |
| |
| Build_Equality_Call |
| (Find_Equality (Primitive_Operations (Typl))); |
| end if; |
| |
| -- Ada 2005 (AI-216): Program_Error is raised when evaluating the |
| -- predefined equality operator for a type which has a subcomponent |
| -- of an Unchecked_Union type whose nominal subtype is unconstrained. |
| |
| elsif Has_Unconstrained_UU_Component (Typl) then |
| Insert_Action (N, |
| Make_Raise_Program_Error (Loc, |
| Reason => PE_Unchecked_Union_Restriction)); |
| |
| -- Prevent Gigi from generating incorrect code by rewriting the |
| -- equality as a standard False. (is this documented somewhere???) |
| |
| Rewrite (N, |
| New_Occurrence_Of (Standard_False, Loc)); |
| |
| elsif Is_Unchecked_Union (Typl) then |
| |
| -- If we can infer the discriminants of the operands, we make a |
| -- call to the TSS equality function. |
| |
| if Has_Inferable_Discriminants (Lhs) |
| and then |
| Has_Inferable_Discriminants (Rhs) |
| then |
| Build_Equality_Call |
| (TSS (Root_Type (Typl), TSS_Composite_Equality)); |
| |
| else |
| -- Ada 2005 (AI-216): Program_Error is raised when evaluating |
| -- the predefined equality operator for an Unchecked_Union type |
| -- if either of the operands lack inferable discriminants. |
| |
| Insert_Action (N, |
| Make_Raise_Program_Error (Loc, |
| Reason => PE_Unchecked_Union_Restriction)); |
| |
| -- Emit a warning on source equalities only, otherwise the |
| -- message may appear out of place due to internal use. The |
| -- warning is unconditional because it is required by the |
| -- language. |
| |
| if Comes_From_Source (N) then |
| Error_Msg_N |
| ("Unchecked_Union discriminants cannot be determined??", |
| N); |
| Error_Msg_N |
| ("\Program_Error will be raised for equality operation??", |
| N); |
| end if; |
| |
| -- Prevent Gigi from generating incorrect code by rewriting |
| -- the equality as a standard False (documented where???). |
| |
| Rewrite (N, |
| New_Occurrence_Of (Standard_False, Loc)); |
| end if; |
| |
| -- If a type support function is present (for complex cases), use it |
| |
| elsif Present (TSS (Root_Type (Typl), TSS_Composite_Equality)) then |
| Build_Equality_Call |
| (TSS (Root_Type (Typl), TSS_Composite_Equality)); |
| |
| -- When comparing two Bounded_Strings, use the primitive equality of |
| -- the root Super_String type. |
| |
| elsif Is_Bounded_String (Typl) then |
| Build_Equality_Call |
| (Find_Equality |
| (Collect_Primitive_Operations (Root_Type (Typl)))); |
| |
| -- Otherwise expand the component by component equality. Note that |
| -- we never use block-bit comparisons for records, because of the |
| -- problems with gaps. The back end will often be able to recombine |
| -- the separate comparisons that we generate here. |
| |
| else |
| Remove_Side_Effects (Lhs); |
| Remove_Side_Effects (Rhs); |
| Rewrite (N, Expand_Record_Equality (N, Typl, Lhs, Rhs)); |
| |
| Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); |
| end if; |
| |
| -- If unnesting, handle elementary types whose Equivalent_Types are |
| -- records because there may be padding or undefined fields. |
| |
| elsif Unnest_Subprogram_Mode |
| and then Ekind (Typl) in E_Class_Wide_Type |
| | E_Class_Wide_Subtype |
| | E_Access_Subprogram_Type |
| | E_Access_Protected_Subprogram_Type |
| | E_Anonymous_Access_Protected_Subprogram_Type |
| | E_Exception_Type |
| and then Present (Equivalent_Type (Typl)) |
| and then Is_Record_Type (Equivalent_Type (Typl)) |
| then |
| Typl := Equivalent_Type (Typl); |
| Remove_Side_Effects (Lhs); |
| Remove_Side_Effects (Rhs); |
| Rewrite (N, |
| Expand_Record_Equality (N, Typl, |
| Unchecked_Convert_To (Typl, Lhs), |
| Unchecked_Convert_To (Typl, Rhs))); |
| |
| Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); |
| end if; |
| |
| -- Test if result is known at compile time |
| |
| Rewrite_Comparison (N); |
| |
| -- Try to narrow the operation |
| |
| if Typl = Universal_Integer and then Nkind (N) = N_Op_Eq then |
| Narrow_Large_Operation (N); |
| end if; |
| |
| -- Special optimization of length comparison |
| |
| Optimize_Length_Comparison (N); |
| |
| -- One more special case: if we have a comparison of X'Result = expr |
| -- in floating-point, then if not already there, change expr to be |
| -- f'Machine (expr) to eliminate surprise from extra precision. |
| |
| if Is_Floating_Point_Type (Typl) |
| and then Is_Attribute_Result (Original_Node (Lhs)) |
| then |
| -- Stick in the Typ'Machine call if not already there |
| |
| if Nkind (Rhs) /= N_Attribute_Reference |
| or else Attribute_Name (Rhs) /= Name_Machine |
| then |
| Rewrite (Rhs, |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Typl, Loc), |
| Attribute_Name => Name_Machine, |
| Expressions => New_List (Relocate_Node (Rhs)))); |
| Analyze_And_Resolve (Rhs, Typl); |
| end if; |
| end if; |
| end Expand_N_Op_Eq; |
| |
| ----------------------- |
| -- Expand_N_Op_Expon -- |
| ----------------------- |
| |
| procedure Expand_N_Op_Expon (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Ovflo : constant Boolean := Do_Overflow_Check (N); |
| Typ : constant Entity_Id := Etype (N); |
| Rtyp : constant Entity_Id := Root_Type (Typ); |
| |
| Bastyp : Entity_Id; |
| |
| function Wrap_MA (Exp : Node_Id) return Node_Id; |
| -- Given an expression Exp, if the root type is Float or Long_Float, |
| -- then wrap the expression in a call of Bastyp'Machine, to stop any |
| -- extra precision. This is done to ensure that X**A = X**B when A is |
| -- a static constant and B is a variable with the same value. For any |
| -- other type, the node Exp is returned unchanged. |
| |
| ------------- |
| -- Wrap_MA -- |
| ------------- |
| |
| function Wrap_MA (Exp : Node_Id) return Node_Id is |
| Loc : constant Source_Ptr := Sloc (Exp); |
| |
| begin |
| if Rtyp = Standard_Float or else Rtyp = Standard_Long_Float then |
| return |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Machine, |
| Prefix => New_Occurrence_Of (Bastyp, Loc), |
| Expressions => New_List (Relocate_Node (Exp))); |
| else |
| return Exp; |
| end if; |
| end Wrap_MA; |
| |
| -- Local variables |
| |
| Base : Node_Id; |
| Ent : Entity_Id; |
| Etyp : Entity_Id; |
| Exp : Node_Id; |
| Exptyp : Entity_Id; |
| Expv : Uint; |
| Rent : RE_Id; |
| Temp : Node_Id; |
| Xnode : Node_Id; |
| |
| -- Start of processing for Expand_N_Op_Expon |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- CodePeer wants to see the unexpanded N_Op_Expon node |
| |
| if CodePeer_Mode then |
| return; |
| end if; |
| |
| -- Relocation of left and right operands must be done after performing |
| -- the validity checks since the generation of validation checks may |
| -- remove side effects. |
| |
| Base := Relocate_Node (Left_Opnd (N)); |
| Bastyp := Etype (Base); |
| Exp := Relocate_Node (Right_Opnd (N)); |
| Exptyp := Etype (Exp); |
| |
| -- If either operand is of a private type, then we have the use of an |
| -- intrinsic operator, and we get rid of the privateness, by using root |
| -- types of underlying types for the actual operation. Otherwise the |
| -- private types will cause trouble if we expand multiplications or |
| -- shifts etc. We also do this transformation if the result type is |
| -- different from the base type. |
| |
| if Is_Private_Type (Etype (Base)) |
| or else Is_Private_Type (Typ) |
| or else Is_Private_Type (Exptyp) |
| or else Rtyp /= Root_Type (Bastyp) |
| then |
| declare |
| Bt : constant Entity_Id := Root_Type (Underlying_Type (Bastyp)); |
| Et : constant Entity_Id := Root_Type (Underlying_Type (Exptyp)); |
| begin |
| Rewrite (N, |
| Unchecked_Convert_To (Typ, |
| Make_Op_Expon (Loc, |
| Left_Opnd => Unchecked_Convert_To (Bt, Base), |
| Right_Opnd => Unchecked_Convert_To (Et, Exp)))); |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end; |
| end if; |
| |
| -- Check for MINIMIZED/ELIMINATED overflow mode |
| |
| if Minimized_Eliminated_Overflow_Check (N) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- Test for case of known right argument where we can replace the |
| -- exponentiation by an equivalent expression using multiplication. |
| |
| -- Note: use CRT_Safe version of Compile_Time_Known_Value because in |
| -- configurable run-time mode, we may not have the exponentiation |
| -- routine available, and we don't want the legality of the program |
| -- to depend on how clever the compiler is in knowing values. |
| |
| if CRT_Safe_Compile_Time_Known_Value (Exp) then |
| Expv := Expr_Value (Exp); |
| |
| -- We only fold small non-negative exponents. You might think we |
| -- could fold small negative exponents for the real case, but we |
| -- can't because we are required to raise Constraint_Error for |
| -- the case of 0.0 ** (negative) even if Machine_Overflows = False. |
| -- See ACVC test C4A012B, and it is not worth generating the test. |
| |
| -- For small negative exponents, we return the reciprocal of |
| -- the folding of the exponentiation for the opposite (positive) |
| -- exponent, as required by Ada RM 4.5.6(11/3). |
| |
| if abs Expv <= 4 then |
| |
| -- X ** 0 = 1 (or 1.0) |
| |
| if Expv = 0 then |
| |
| -- Call Remove_Side_Effects to ensure that any side effects |
| -- in the ignored left operand (in particular function calls |
| -- to user defined functions) are properly executed. |
| |
| Remove_Side_Effects (Base); |
| |
| if Ekind (Typ) in Integer_Kind then |
| Xnode := Make_Integer_Literal (Loc, Intval => 1); |
| else |
| Xnode := Make_Real_Literal (Loc, Ureal_1); |
| end if; |
| |
| -- X ** 1 = X |
| |
| elsif Expv = 1 then |
| Xnode := Base; |
| |
| -- X ** 2 = X * X |
| |
| elsif Expv = 2 then |
| Xnode := |
| Wrap_MA ( |
| Make_Op_Multiply (Loc, |
| Left_Opnd => Duplicate_Subexpr (Base), |
| Right_Opnd => Duplicate_Subexpr_No_Checks (Base))); |
| |
| -- X ** 3 = X * X * X |
| |
| elsif Expv = 3 then |
| Xnode := |
| Wrap_MA ( |
| Make_Op_Multiply (Loc, |
| Left_Opnd => |
| Make_Op_Multiply (Loc, |
| Left_Opnd => Duplicate_Subexpr (Base), |
| Right_Opnd => Duplicate_Subexpr_No_Checks (Base)), |
| Right_Opnd => Duplicate_Subexpr_No_Checks (Base))); |
| |
| -- X ** 4 -> |
| |
| -- do |
| -- En : constant base'type := base * base; |
| -- in |
| -- En * En |
| |
| elsif Expv = 4 then |
| Temp := Make_Temporary (Loc, 'E', Base); |
| |
| Xnode := |
| Make_Expression_With_Actions (Loc, |
| Actions => New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Constant_Present => True, |
| Object_Definition => New_Occurrence_Of (Typ, Loc), |
| Expression => |
| Wrap_MA ( |
| Make_Op_Multiply (Loc, |
| Left_Opnd => |
| Duplicate_Subexpr (Base), |
| Right_Opnd => |
| Duplicate_Subexpr_No_Checks (Base))))), |
| |
| Expression => |
| Wrap_MA ( |
| Make_Op_Multiply (Loc, |
| Left_Opnd => New_Occurrence_Of (Temp, Loc), |
| Right_Opnd => New_Occurrence_Of (Temp, Loc)))); |
| |
| -- X ** N = 1.0 / X ** (-N) |
| -- N in -4 .. -1 |
| |
| else |
| pragma Assert |
| (Expv = -1 or Expv = -2 or Expv = -3 or Expv = -4); |
| |
| Xnode := |
| Make_Op_Divide (Loc, |
| Left_Opnd => |
| Make_Float_Literal (Loc, |
| Radix => Uint_1, |
| Significand => Uint_1, |
| Exponent => Uint_0), |
| Right_Opnd => |
| Make_Op_Expon (Loc, |
| Left_Opnd => Duplicate_Subexpr (Base), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, |
| Intval => -Expv))); |
| end if; |
| |
| Rewrite (N, Xnode); |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end if; |
| end if; |
| |
| -- Deal with optimizing 2 ** expression to shift where possible |
| |
| -- Note: we used to check that Exptyp was an unsigned type. But that is |
| -- an unnecessary check, since if Exp is negative, we have a run-time |
| -- error that is either caught (so we get the right result) or we have |
| -- suppressed the check, in which case the code is erroneous anyway. |
| |
| if Is_Integer_Type (Rtyp) |
| |
| -- The base value must be "safe compile-time known", and exactly 2 |
| |
| and then Nkind (Base) = N_Integer_Literal |
| and then CRT_Safe_Compile_Time_Known_Value (Base) |
| and then Expr_Value (Base) = Uint_2 |
| |
| -- We only handle cases where the right type is a integer |
| |
| and then Is_Integer_Type (Root_Type (Exptyp)) |
| and then Esize (Root_Type (Exptyp)) <= Standard_Integer_Size |
| |
| -- This transformation is not applicable for a modular type with a |
| -- nonbinary modulus because we do not handle modular reduction in |
| -- a correct manner if we attempt this transformation in this case. |
| |
| and then not Non_Binary_Modulus (Typ) |
| then |
| -- Handle the cases where our parent is a division or multiplication |
| -- specially. In these cases we can convert to using a shift at the |
| -- parent level if we are not doing overflow checking, since it is |
| -- too tricky to combine the overflow check at the parent level. |
| |
| if not Ovflo |
| and then Nkind (Parent (N)) in N_Op_Divide | N_Op_Multiply |
| then |
| declare |
| P : constant Node_Id := Parent (N); |
| L : constant Node_Id := Left_Opnd (P); |
| R : constant Node_Id := Right_Opnd (P); |
| |
| begin |
| if (Nkind (P) = N_Op_Multiply |
| and then |
| ((Is_Integer_Type (Etype (L)) and then R = N) |
| or else |
| (Is_Integer_Type (Etype (R)) and then L = N)) |
| and then not Do_Overflow_Check (P)) |
| |
| or else |
| (Nkind (P) = N_Op_Divide |
| and then Is_Integer_Type (Etype (L)) |
| and then Is_Unsigned_Type (Etype (L)) |
| and then R = N |
| and then not Do_Overflow_Check (P)) |
| then |
| Set_Is_Power_Of_2_For_Shift (N); |
| return; |
| end if; |
| end; |
| |
| -- Here we just have 2 ** N on its own, so we can convert this to a |
| -- shift node. We are prepared to deal with overflow here, and we |
| -- also have to handle proper modular reduction for binary modular. |
| |
| else |
| declare |
| OK : Boolean; |
| Lo : Uint; |
| Hi : Uint; |
| |
| MaxS : Uint; |
| -- Maximum shift count with no overflow |
| |
| TestS : Boolean; |
| -- Set True if we must test the shift count |
| |
| Test_Gt : Node_Id; |
| -- Node for test against TestS |
| |
| begin |
| -- Compute maximum shift based on the underlying size. For a |
| -- modular type this is one less than the size. |
| |
| if Is_Modular_Integer_Type (Typ) then |
| |
| -- For modular integer types, this is the size of the value |
| -- being shifted minus one. Any larger values will cause |
| -- modular reduction to a result of zero. Note that we do |
| -- want the RM_Size here (e.g. mod 2 ** 7, we want a result |
| -- of 6, since 2**7 should be reduced to zero). |
| |
| MaxS := RM_Size (Rtyp) - 1; |
| |
| -- For signed integer types, we use the size of the value |
| -- being shifted minus 2. Larger values cause overflow. |
| |
| else |
| MaxS := Esize (Rtyp) - 2; |
| end if; |
| |
| -- Determine range to see if it can be larger than MaxS |
| |
| Determine_Range (Exp, OK, Lo, Hi, Assume_Valid => True); |
| TestS := (not OK) or else Hi > MaxS; |
| |
| -- Signed integer case |
| |
| if Is_Signed_Integer_Type (Typ) then |
| |
| -- Generate overflow check if overflow is active. Note that |
| -- we can simply ignore the possibility of overflow if the |
| -- flag is not set (means that overflow cannot happen or |
| -- that overflow checks are suppressed). |
| |
| if Ovflo and TestS then |
| Insert_Action (N, |
| Make_Raise_Constraint_Error (Loc, |
| Condition => |
| Make_Op_Gt (Loc, |
| Left_Opnd => Duplicate_Subexpr (Exp), |
| Right_Opnd => Make_Integer_Literal (Loc, MaxS)), |
| Reason => CE_Overflow_Check_Failed)); |
| end if; |
| |
| -- Now rewrite node as Shift_Left (1, right-operand) |
| |
| Rewrite (N, |
| Make_Op_Shift_Left (Loc, |
| Left_Opnd => Make_Integer_Literal (Loc, Uint_1), |
| Right_Opnd => Exp)); |
| |
| -- Modular integer case |
| |
| else pragma Assert (Is_Modular_Integer_Type (Typ)); |
| |
| -- If shift count can be greater than MaxS, we need to wrap |
| -- the shift in a test that will reduce the result value to |
| -- zero if this shift count is exceeded. |
| |
| if TestS then |
| |
| -- Note: build node for the comparison first, before we |
| -- reuse the Right_Opnd, so that we have proper parents |
| -- in place for the Duplicate_Subexpr call. |
| |
| Test_Gt := |
| Make_Op_Gt (Loc, |
| Left_Opnd => Duplicate_Subexpr (Exp), |
| Right_Opnd => Make_Integer_Literal (Loc, MaxS)); |
| |
| Rewrite (N, |
| Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Test_Gt, |
| Make_Integer_Literal (Loc, Uint_0), |
| Make_Op_Shift_Left (Loc, |
| Left_Opnd => Make_Integer_Literal (Loc, Uint_1), |
| Right_Opnd => Exp)))); |
| |
| -- If we know shift count cannot be greater than MaxS, then |
| -- it is safe to just rewrite as a shift with no test. |
| |
| else |
| Rewrite (N, |
| Make_Op_Shift_Left (Loc, |
| Left_Opnd => Make_Integer_Literal (Loc, Uint_1), |
| Right_Opnd => Exp)); |
| end if; |
| end if; |
| |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end; |
| end if; |
| end if; |
| |
| -- Fall through if exponentiation must be done using a runtime routine |
| |
| -- First deal with modular case |
| |
| if Is_Modular_Integer_Type (Rtyp) then |
| |
| -- Nonbinary modular case, we call the special exponentiation |
| -- routine for the nonbinary case, converting the argument to |
| -- Long_Long_Integer and passing the modulus value. Then the |
| -- result is converted back to the base type. |
| |
| if Non_Binary_Modulus (Rtyp) then |
| Rewrite (N, |
| Convert_To (Typ, |
| Make_Function_Call (Loc, |
| Name => |
| New_Occurrence_Of (RTE (RE_Exp_Modular), Loc), |
| Parameter_Associations => New_List ( |
| Convert_To (RTE (RE_Unsigned), Base), |
| Make_Integer_Literal (Loc, Modulus (Rtyp)), |
| Exp)))); |
| |
| -- Binary modular case, in this case, we call one of three routines, |
| -- either the unsigned integer case, or the unsigned long long |
| -- integer case, or the unsigned long long long integer case, with a |
| -- final "and" operation to do the required mod. |
| |
| else |
| if Esize (Rtyp) <= Standard_Integer_Size then |
| Ent := RTE (RE_Exp_Unsigned); |
| elsif Esize (Rtyp) <= Standard_Long_Long_Integer_Size then |
| Ent := RTE (RE_Exp_Long_Long_Unsigned); |
| else |
| Ent := RTE (RE_Exp_Long_Long_Long_Unsigned); |
| end if; |
| |
| Rewrite (N, |
| Convert_To (Typ, |
| Make_Op_And (Loc, |
| Left_Opnd => |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Ent, Loc), |
| Parameter_Associations => New_List ( |
| Convert_To (Etype (First_Formal (Ent)), Base), |
| Exp)), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, Modulus (Rtyp) - 1)))); |
| |
| end if; |
| |
| -- Common exit point for modular type case |
| |
| Analyze_And_Resolve (N, Typ); |
| return; |
| |
| -- Signed integer cases, using either Integer, Long_Long_Integer or |
| -- Long_Long_Long_Integer. It is not worth also having routines for |
| -- Short_[Short_]Integer, since for most machines it would not help, |
| -- and it would generate more code that might need certification when |
| -- a certified run time is required. |
| |
| -- In the integer cases, we have two routines, one for when overflow |
| -- checks are required, and one when they are not required, since there |
| -- is a real gain in omitting checks on many machines. |
| |
| elsif Is_Signed_Integer_Type (Rtyp) then |
| if Esize (Rtyp) <= Standard_Integer_Size then |
| Etyp := Standard_Integer; |
| |
| if Ovflo then |
| Rent := RE_Exp_Integer; |
| else |
| Rent := RE_Exn_Integer; |
| end if; |
| |
| elsif Esize (Rtyp) <= Standard_Long_Long_Integer_Size then |
| Etyp := Standard_Long_Long_Integer; |
| |
| if Ovflo then |
| Rent := RE_Exp_Long_Long_Integer; |
| else |
| Rent := RE_Exn_Long_Long_Integer; |
| end if; |
| |
| else |
| Etyp := Standard_Long_Long_Long_Integer; |
| |
| if Ovflo then |
| Rent := RE_Exp_Long_Long_Long_Integer; |
| else |
| Rent := RE_Exn_Long_Long_Long_Integer; |
| end if; |
| end if; |
| |
| -- Floating-point cases. We do not need separate routines for the |
| -- overflow case here, since in the case of floating-point, we generate |
| -- infinities anyway as a rule (either that or we automatically trap |
| -- overflow), and if there is an infinity generated and a range check |
| -- is required, the check will fail anyway. |
| |
| else |
| pragma Assert (Is_Floating_Point_Type (Rtyp)); |
| |
| -- Short_Float and Float are the same type for GNAT |
| |
| if Rtyp = Standard_Short_Float or else Rtyp = Standard_Float then |
| Etyp := Standard_Float; |
| Rent := RE_Exn_Float; |
| |
| elsif Rtyp = Standard_Long_Float then |
| Etyp := Standard_Long_Float; |
| Rent := RE_Exn_Long_Float; |
| |
| else |
| Etyp := Standard_Long_Long_Float; |
| Rent := RE_Exn_Long_Long_Float; |
| end if; |
| end if; |
| |
| -- Common processing for integer cases and floating-point cases. |
| -- If we are in the right type, we can call runtime routine directly |
| |
| if Typ = Etyp |
| and then not Is_Universal_Numeric_Type (Rtyp) |
| then |
| Rewrite (N, |
| Wrap_MA ( |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (RTE (Rent), Loc), |
| Parameter_Associations => New_List (Base, Exp)))); |
| |
| -- Otherwise we have to introduce conversions (conversions are also |
| -- required in the universal cases, since the runtime routine is |
| -- typed using one of the standard types). |
| |
| else |
| Rewrite (N, |
| Convert_To (Typ, |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (RTE (Rent), Loc), |
| Parameter_Associations => New_List ( |
| Convert_To (Etyp, Base), |
| Exp)))); |
| end if; |
| |
| Analyze_And_Resolve (N, Typ); |
| return; |
| |
| exception |
| when RE_Not_Available => |
| return; |
| end Expand_N_Op_Expon; |
| |
| -------------------- |
| -- Expand_N_Op_Ge -- |
| -------------------- |
| |
| procedure Expand_N_Op_Ge (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| Op1 : constant Node_Id := Left_Opnd (N); |
| Op2 : constant Node_Id := Right_Opnd (N); |
| Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that |
| -- means we no longer have a comparison operation, we are all done. |
| |
| if Minimized_Eliminated_Overflow_Check (Op1) then |
| Expand_Compare_Minimize_Eliminate_Overflow (N); |
| end if; |
| |
| if Nkind (N) /= N_Op_Ge then |
| return; |
| end if; |
| |
| -- Array type case |
| |
| if Is_Array_Type (Typ1) then |
| Expand_Array_Comparison (N); |
| return; |
| end if; |
| |
| -- Deal with boolean operands |
| |
| if Is_Boolean_Type (Typ1) then |
| Adjust_Condition (Op1); |
| Adjust_Condition (Op2); |
| Set_Etype (N, Standard_Boolean); |
| Adjust_Result_Type (N, Typ); |
| end if; |
| |
| Rewrite_Comparison (N); |
| |
| -- Try to narrow the operation |
| |
| if Typ1 = Universal_Integer and then Nkind (N) = N_Op_Ge then |
| Narrow_Large_Operation (N); |
| end if; |
| |
| Optimize_Length_Comparison (N); |
| end Expand_N_Op_Ge; |
| |
| -------------------- |
| -- Expand_N_Op_Gt -- |
| -------------------- |
| |
| procedure Expand_N_Op_Gt (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| Op1 : constant Node_Id := Left_Opnd (N); |
| Op2 : constant Node_Id := Right_Opnd (N); |
| Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that |
| -- means we no longer have a comparison operation, we are all done. |
| |
| if Minimized_Eliminated_Overflow_Check (Op1) then |
| Expand_Compare_Minimize_Eliminate_Overflow (N); |
| end if; |
| |
| if Nkind (N) /= N_Op_Gt then |
| return; |
| end if; |
| |
| -- Deal with array type operands |
| |
| if Is_Array_Type (Typ1) then |
| Expand_Array_Comparison (N); |
| return; |
| end if; |
| |
| -- Deal with boolean type operands |
| |
| if Is_Boolean_Type (Typ1) then |
| Adjust_Condition (Op1); |
| Adjust_Condition (Op2); |
| Set_Etype (N, Standard_Boolean); |
| Adjust_Result_Type (N, Typ); |
| end if; |
| |
| Rewrite_Comparison (N); |
| |
| -- Try to narrow the operation |
| |
| if Typ1 = Universal_Integer and then Nkind (N) = N_Op_Gt then |
| Narrow_Large_Operation (N); |
| end if; |
| |
| Optimize_Length_Comparison (N); |
| end Expand_N_Op_Gt; |
| |
| -------------------- |
| -- Expand_N_Op_Le -- |
| -------------------- |
| |
| procedure Expand_N_Op_Le (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| Op1 : constant Node_Id := Left_Opnd (N); |
| Op2 : constant Node_Id := Right_Opnd (N); |
| Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that |
| -- means we no longer have a comparison operation, we are all done. |
| |
| if Minimized_Eliminated_Overflow_Check (Op1) then |
| Expand_Compare_Minimize_Eliminate_Overflow (N); |
| end if; |
| |
| if Nkind (N) /= N_Op_Le then |
| return; |
| end if; |
| |
| -- Deal with array type operands |
| |
| if Is_Array_Type (Typ1) then |
| Expand_Array_Comparison (N); |
| return; |
| end if; |
| |
| -- Deal with Boolean type operands |
| |
| if Is_Boolean_Type (Typ1) then |
| Adjust_Condition (Op1); |
| Adjust_Condition (Op2); |
| Set_Etype (N, Standard_Boolean); |
| Adjust_Result_Type (N, Typ); |
| end if; |
| |
| Rewrite_Comparison (N); |
| |
| -- Try to narrow the operation |
| |
| if Typ1 = Universal_Integer and then Nkind (N) = N_Op_Le then |
| Narrow_Large_Operation (N); |
| end if; |
| |
| Optimize_Length_Comparison (N); |
| end Expand_N_Op_Le; |
| |
| -------------------- |
| -- Expand_N_Op_Lt -- |
| -------------------- |
| |
| procedure Expand_N_Op_Lt (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| Op1 : constant Node_Id := Left_Opnd (N); |
| Op2 : constant Node_Id := Right_Opnd (N); |
| Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that |
| -- means we no longer have a comparison operation, we are all done. |
| |
| if Minimized_Eliminated_Overflow_Check (Op1) then |
| Expand_Compare_Minimize_Eliminate_Overflow (N); |
| end if; |
| |
| if Nkind (N) /= N_Op_Lt then |
| return; |
| end if; |
| |
| -- Deal with array type operands |
| |
| if Is_Array_Type (Typ1) then |
| Expand_Array_Comparison (N); |
| return; |
| end if; |
| |
| -- Deal with Boolean type operands |
| |
| if Is_Boolean_Type (Typ1) then |
| Adjust_Condition (Op1); |
| Adjust_Condition (Op2); |
| Set_Etype (N, Standard_Boolean); |
| Adjust_Result_Type (N, Typ); |
| end if; |
| |
| Rewrite_Comparison (N); |
| |
| -- Try to narrow the operation |
| |
| if Typ1 = Universal_Integer and then Nkind (N) = N_Op_Lt then |
| Narrow_Large_Operation (N); |
| end if; |
| |
| Optimize_Length_Comparison (N); |
| end Expand_N_Op_Lt; |
| |
| ----------------------- |
| -- Expand_N_Op_Minus -- |
| ----------------------- |
| |
| procedure Expand_N_Op_Minus (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| |
| begin |
| Unary_Op_Validity_Checks (N); |
| |
| -- Check for MINIMIZED/ELIMINATED overflow mode |
| |
| if Minimized_Eliminated_Overflow_Check (N) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- Try to narrow the operation |
| |
| if Typ = Universal_Integer then |
| Narrow_Large_Operation (N); |
| |
| if Nkind (N) /= N_Op_Minus then |
| return; |
| end if; |
| end if; |
| |
| if not Backend_Overflow_Checks_On_Target |
| and then Is_Signed_Integer_Type (Typ) |
| and then Do_Overflow_Check (N) |
| then |
| -- Software overflow checking expands -expr into (0 - expr) |
| |
| Rewrite (N, |
| Make_Op_Subtract (Loc, |
| Left_Opnd => Make_Integer_Literal (Loc, 0), |
| Right_Opnd => Right_Opnd (N))); |
| |
| Analyze_And_Resolve (N, Typ); |
| end if; |
| |
| Expand_Nonbinary_Modular_Op (N); |
| end Expand_N_Op_Minus; |
| |
| --------------------- |
| -- Expand_N_Op_Mod -- |
| --------------------- |
| |
| procedure Expand_N_Op_Mod (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| DDC : constant Boolean := Do_Division_Check (N); |
| |
| Left : Node_Id; |
| Right : Node_Id; |
| |
| LLB : Uint; |
| Llo : Uint; |
| Lhi : Uint; |
| LOK : Boolean; |
| Rlo : Uint; |
| Rhi : Uint; |
| ROK : Boolean; |
| |
| pragma Warnings (Off, Lhi); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- Check for MINIMIZED/ELIMINATED overflow mode |
| |
| if Minimized_Eliminated_Overflow_Check (N) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- Try to narrow the operation |
| |
| if Typ = Universal_Integer then |
| Narrow_Large_Operation (N); |
| |
| if Nkind (N) /= N_Op_Mod then |
| return; |
| end if; |
| end if; |
| |
| if Is_Integer_Type (Typ) then |
| Apply_Divide_Checks (N); |
| |
| -- All done if we don't have a MOD any more, which can happen as a |
| -- result of overflow expansion in MINIMIZED or ELIMINATED modes. |
| |
| if Nkind (N) /= N_Op_Mod then |
| return; |
| end if; |
| end if; |
| |
| -- Proceed with expansion of mod operator |
| |
| Left := Left_Opnd (N); |
| Right := Right_Opnd (N); |
| |
| Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True); |
| Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True); |
| |
| -- Convert mod to rem if operands are both known to be non-negative, or |
| -- both known to be non-positive (these are the cases in which rem and |
| -- mod are the same, see (RM 4.5.5(28-30)). We do this since it is quite |
| -- likely that this will improve the quality of code, (the operation now |
| -- corresponds to the hardware remainder), and it does not seem likely |
| -- that it could be harmful. It also avoids some cases of the elaborate |
| -- expansion in Modify_Tree_For_C mode below (since Ada rem = C %). |
| |
| if (LOK and ROK) |
| and then ((Llo >= 0 and then Rlo >= 0) |
| or else |
| (Lhi <= 0 and then Rhi <= 0)) |
| then |
| Rewrite (N, |
| Make_Op_Rem (Sloc (N), |
| Left_Opnd => Left_Opnd (N), |
| Right_Opnd => Right_Opnd (N))); |
| |
| -- Instead of reanalyzing the node we do the analysis manually. This |
| -- avoids anomalies when the replacement is done in an instance and |
| -- is epsilon more efficient. |
| |
| Set_Entity (N, Standard_Entity (S_Op_Rem)); |
| Set_Etype (N, Typ); |
| Set_Do_Division_Check (N, DDC); |
| Expand_N_Op_Rem (N); |
| Set_Analyzed (N); |
| return; |
| |
| -- Otherwise, normal mod processing |
| |
| else |
| -- Apply optimization x mod 1 = 0. We don't really need that with |
| -- gcc, but it is useful with other back ends and is certainly |
| -- harmless. |
| |
| if Is_Integer_Type (Etype (N)) |
| and then Compile_Time_Known_Value (Right) |
| and then Expr_Value (Right) = Uint_1 |
| then |
| -- Call Remove_Side_Effects to ensure that any side effects in |
| -- the ignored left operand (in particular function calls to |
| -- user defined functions) are properly executed. |
| |
| Remove_Side_Effects (Left); |
| |
| Rewrite (N, Make_Integer_Literal (Loc, 0)); |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end if; |
| |
| -- If we still have a mod operator and we are in Modify_Tree_For_C |
| -- mode, and we have a signed integer type, then here is where we do |
| -- the rewrite in terms of Rem. Note this rewrite bypasses the need |
| -- for the special handling of the annoying case of largest negative |
| -- number mod minus one. |
| |
| if Nkind (N) = N_Op_Mod |
| and then Is_Signed_Integer_Type (Typ) |
| and then Modify_Tree_For_C |
| then |
| -- In the general case, we expand A mod B as |
| |
| -- Tnn : constant typ := A rem B; |
| -- .. |
| -- (if (A >= 0) = (B >= 0) then Tnn |
| -- elsif Tnn = 0 then 0 |
| -- else Tnn + B) |
| |
| -- The comparison can be written simply as A >= 0 if we know that |
| -- B >= 0 which is a very common case. |
| |
| -- An important optimization is when B is known at compile time |
| -- to be 2**K for some constant. In this case we can simply AND |
| -- the left operand with the bit string 2**K-1 (i.e. K 1-bits) |
| -- and that works for both the positive and negative cases. |
| |
| declare |
| P2 : constant Nat := Power_Of_Two (Right); |
| |
| begin |
| if P2 /= 0 then |
| Rewrite (N, |
| Unchecked_Convert_To (Typ, |
| Make_Op_And (Loc, |
| Left_Opnd => |
| Unchecked_Convert_To |
| (Corresponding_Unsigned_Type (Typ), Left), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, 2 ** P2 - 1)))); |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end if; |
| end; |
| |
| -- Here for the full rewrite |
| |
| declare |
| Tnn : constant Entity_Id := Make_Temporary (Sloc (N), 'T', N); |
| Cmp : Node_Id; |
| |
| begin |
| Cmp := |
| Make_Op_Ge (Loc, |
| Left_Opnd => Duplicate_Subexpr_No_Checks (Left), |
| Right_Opnd => Make_Integer_Literal (Loc, 0)); |
| |
| if not LOK or else Rlo < 0 then |
| Cmp := |
| Make_Op_Eq (Loc, |
| Left_Opnd => Cmp, |
| Right_Opnd => |
| Make_Op_Ge (Loc, |
| Left_Opnd => Duplicate_Subexpr_No_Checks (Right), |
| Right_Opnd => Make_Integer_Literal (Loc, 0))); |
| end if; |
| |
| Insert_Action (N, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Tnn, |
| Constant_Present => True, |
| Object_Definition => New_Occurrence_Of (Typ, Loc), |
| Expression => |
| Make_Op_Rem (Loc, |
| Left_Opnd => Left, |
| Right_Opnd => Right))); |
| |
| Rewrite (N, |
| Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Cmp, |
| New_Occurrence_Of (Tnn, Loc), |
| Make_If_Expression (Loc, |
| Is_Elsif => True, |
| Expressions => New_List ( |
| Make_Op_Eq (Loc, |
| Left_Opnd => New_Occurrence_Of (Tnn, Loc), |
| Right_Opnd => Make_Integer_Literal (Loc, 0)), |
| Make_Integer_Literal (Loc, 0), |
| Make_Op_Add (Loc, |
| Left_Opnd => New_Occurrence_Of (Tnn, Loc), |
| Right_Opnd => |
| Duplicate_Subexpr_No_Checks (Right))))))); |
| |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end; |
| end if; |
| |
| -- Deal with annoying case of largest negative number mod minus one. |
| -- Gigi may not handle this case correctly, because on some targets, |
| -- the mod value is computed using a divide instruction which gives |
| -- an overflow trap for this case. |
| |
| -- It would be a bit more efficient to figure out which targets |
| -- this is really needed for, but in practice it is reasonable |
| -- to do the following special check in all cases, since it means |
| -- we get a clearer message, and also the overhead is minimal given |
| -- that division is expensive in any case. |
| |
| -- In fact the check is quite easy, if the right operand is -1, then |
| -- the mod value is always 0, and we can just ignore the left operand |
| -- completely in this case. |
| |
| -- This only applies if we still have a mod operator. Skip if we |
| -- have already rewritten this (e.g. in the case of eliminated |
| -- overflow checks which have driven us into bignum mode). |
| |
| if Nkind (N) = N_Op_Mod then |
| |
| -- The operand type may be private (e.g. in the expansion of an |
| -- intrinsic operation) so we must use the underlying type to get |
| -- the bounds, and convert the literals explicitly. |
| |
| LLB := |
| Expr_Value |
| (Type_Low_Bound (Base_Type (Underlying_Type (Etype (Left))))); |
| |
| if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) |
| and then ((not LOK) or else (Llo = LLB)) |
| and then not CodePeer_Mode |
| then |
| Rewrite (N, |
| Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Make_Op_Eq (Loc, |
| Left_Opnd => Duplicate_Subexpr (Right), |
| Right_Opnd => |
| Unchecked_Convert_To (Typ, |
| Make_Integer_Literal (Loc, -1))), |
| Unchecked_Convert_To (Typ, |
| Make_Integer_Literal (Loc, Uint_0)), |
| Relocate_Node (N)))); |
| |
| Set_Analyzed (Next (Next (First (Expressions (N))))); |
| Analyze_And_Resolve (N, Typ); |
| end if; |
| end if; |
| end if; |
| end Expand_N_Op_Mod; |
| |
| -------------------------- |
| -- Expand_N_Op_Multiply -- |
| -------------------------- |
| |
| procedure Expand_N_Op_Multiply (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Lop : constant Node_Id := Left_Opnd (N); |
| Rop : constant Node_Id := Right_Opnd (N); |
| |
| Lp2 : constant Boolean := |
| Nkind (Lop) = N_Op_Expon and then Is_Power_Of_2_For_Shift (Lop); |
| Rp2 : constant Boolean := |
| Nkind (Rop) = N_Op_Expon and then Is_Power_Of_2_For_Shift (Rop); |
| |
| Ltyp : constant Entity_Id := Etype (Lop); |
| Rtyp : constant Entity_Id := Etype (Rop); |
| Typ : Entity_Id := Etype (N); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- Check for MINIMIZED/ELIMINATED overflow mode |
| |
| if Minimized_Eliminated_Overflow_Check (N) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- Special optimizations for integer types |
| |
| if Is_Integer_Type (Typ) then |
| |
| -- N * 0 = 0 for integer types |
| |
| if Compile_Time_Known_Value (Rop) |
| and then Expr_Value (Rop) = Uint_0 |
| then |
| -- Call Remove_Side_Effects to ensure that any side effects in |
| -- the ignored left operand (in particular function calls to |
| -- user defined functions) are properly executed. |
| |
| Remove_Side_Effects (Lop); |
| |
| Rewrite (N, Make_Integer_Literal (Loc, Uint_0)); |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end if; |
| |
| -- Similar handling for 0 * N = 0 |
| |
| if Compile_Time_Known_Value (Lop) |
| and then Expr_Value (Lop) = Uint_0 |
| then |
| Remove_Side_Effects (Rop); |
| Rewrite (N, Make_Integer_Literal (Loc, Uint_0)); |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end if; |
| |
| -- N * 1 = 1 * N = N for integer types |
| |
| -- This optimisation is not done if we are going to |
| -- rewrite the product 1 * 2 ** N to a shift. |
| |
| if Compile_Time_Known_Value (Rop) |
| and then Expr_Value (Rop) = Uint_1 |
| and then not Lp2 |
| then |
| Rewrite (N, Lop); |
| return; |
| |
| elsif Compile_Time_Known_Value (Lop) |
| and then Expr_Value (Lop) = Uint_1 |
| and then not Rp2 |
| then |
| Rewrite (N, Rop); |
| return; |
| end if; |
| end if; |
| |
| -- Convert x * 2 ** y to Shift_Left (x, y). Note that the fact that |
| -- Is_Power_Of_2_For_Shift is set means that we know that our left |
| -- operand is an integer, as required for this to work. |
| |
| if Rp2 then |
| if Lp2 then |
| |
| -- Convert 2 ** A * 2 ** B into 2 ** (A + B) |
| |
| Rewrite (N, |
| Make_Op_Expon (Loc, |
| Left_Opnd => Make_Integer_Literal (Loc, 2), |
| Right_Opnd => |
| Make_Op_Add (Loc, |
| Left_Opnd => Right_Opnd (Lop), |
| Right_Opnd => Right_Opnd (Rop)))); |
| Analyze_And_Resolve (N, Typ); |
| return; |
| |
| else |
| -- If the result is modular, perform the reduction of the result |
| -- appropriately. |
| |
| if Is_Modular_Integer_Type (Typ) |
| and then not Non_Binary_Modulus (Typ) |
| then |
| Rewrite (N, |
| Make_Op_And (Loc, |
| Left_Opnd => |
| Make_Op_Shift_Left (Loc, |
| Left_Opnd => Lop, |
| Right_Opnd => |
| Convert_To (Standard_Natural, Right_Opnd (Rop))), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, Modulus (Typ) - 1))); |
| |
| else |
| Rewrite (N, |
| Make_Op_Shift_Left (Loc, |
| Left_Opnd => Lop, |
| Right_Opnd => |
| Convert_To (Standard_Natural, Right_Opnd (Rop)))); |
| end if; |
| |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end if; |
| |
| -- Same processing for the operands the other way round |
| |
| elsif Lp2 then |
| if Is_Modular_Integer_Type (Typ) |
| and then not Non_Binary_Modulus (Typ) |
| then |
| Rewrite (N, |
| Make_Op_And (Loc, |
| Left_Opnd => |
| Make_Op_Shift_Left (Loc, |
| Left_Opnd => Rop, |
| Right_Opnd => |
| Convert_To (Standard_Natural, Right_Opnd (Lop))), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, Modulus (Typ) - 1))); |
| |
| else |
| Rewrite (N, |
| Make_Op_Shift_Left (Loc, |
| Left_Opnd => Rop, |
| Right_Opnd => |
| Convert_To (Standard_Natural, Right_Opnd (Lop)))); |
| end if; |
| |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end if; |
| |
| -- Try to narrow the operation |
| |
| if Typ = Universal_Integer then |
| Narrow_Large_Operation (N); |
| |
| if Nkind (N) /= N_Op_Multiply then |
| return; |
| end if; |
| end if; |
| |
| -- Do required fixup of universal fixed operation |
| |
| if Typ = Universal_Fixed then |
| Fixup_Universal_Fixed_Operation (N); |
| Typ := Etype (N); |
| end if; |
| |
| -- Multiplications with fixed-point results |
| |
| if Is_Fixed_Point_Type (Typ) then |
| |
| -- Case of fixed * integer => fixed |
| |
| if Is_Integer_Type (Rtyp) then |
| Expand_Multiply_Fixed_By_Integer_Giving_Fixed (N); |
| |
| -- Case of integer * fixed => fixed |
| |
| elsif Is_Integer_Type (Ltyp) then |
| Expand_Multiply_Integer_By_Fixed_Giving_Fixed (N); |
| |
| -- Case of fixed * fixed => fixed |
| |
| else |
| Expand_Multiply_Fixed_By_Fixed_Giving_Fixed (N); |
| end if; |
| |
| -- Other cases of multiplication of fixed-point operands |
| |
| elsif Is_Fixed_Point_Type (Ltyp) or else Is_Fixed_Point_Type (Rtyp) then |
| if Is_Integer_Type (Typ) then |
| Expand_Multiply_Fixed_By_Fixed_Giving_Integer (N); |
| else |
| pragma Assert (Is_Floating_Point_Type (Typ)); |
| Expand_Multiply_Fixed_By_Fixed_Giving_Float (N); |
| end if; |
| |
| -- Mixed-mode operations can appear in a non-static universal context, |
| -- in which case the integer argument must be converted explicitly. |
| |
| elsif Typ = Universal_Real and then Is_Integer_Type (Rtyp) then |
| Rewrite (Rop, Convert_To (Universal_Real, Relocate_Node (Rop))); |
| Analyze_And_Resolve (Rop, Universal_Real); |
| |
| elsif Typ = Universal_Real and then Is_Integer_Type (Ltyp) then |
| Rewrite (Lop, Convert_To (Universal_Real, Relocate_Node (Lop))); |
| Analyze_And_Resolve (Lop, Universal_Real); |
| |
| -- Non-fixed point cases, check software overflow checking required |
| |
| elsif Is_Signed_Integer_Type (Etype (N)) then |
| Apply_Arithmetic_Overflow_Check (N); |
| end if; |
| |
| -- Overflow checks for floating-point if -gnateF mode active |
| |
| Check_Float_Op_Overflow (N); |
| |
| Expand_Nonbinary_Modular_Op (N); |
| end Expand_N_Op_Multiply; |
| |
| -------------------- |
| -- Expand_N_Op_Ne -- |
| -------------------- |
| |
| procedure Expand_N_Op_Ne (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (Left_Opnd (N)); |
| |
| begin |
| -- Case of elementary type with standard operator. But if unnesting, |
| -- handle elementary types whose Equivalent_Types are records because |
| -- there may be padding or undefined fields. |
| |
| if Is_Elementary_Type (Typ) |
| and then Sloc (Entity (N)) = Standard_Location |
| and then not (Ekind (Typ) in E_Class_Wide_Type |
| | E_Class_Wide_Subtype |
| | E_Access_Subprogram_Type |
| | E_Access_Protected_Subprogram_Type |
| | E_Anonymous_Access_Protected_Subprogram_Type |
| | E_Exception_Type |
| and then Present (Equivalent_Type (Typ)) |
| and then Is_Record_Type (Equivalent_Type (Typ))) |
| then |
| Binary_Op_Validity_Checks (N); |
| |
| -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if |
| -- means we no longer have a /= operation, we are all done. |
| |
| if Minimized_Eliminated_Overflow_Check (Left_Opnd (N)) then |
| Expand_Compare_Minimize_Eliminate_Overflow (N); |
| end if; |
| |
| if Nkind (N) /= N_Op_Ne then |
| return; |
| end if; |
| |
| -- Boolean types (requiring handling of non-standard case) |
| |
| if Is_Boolean_Type (Typ) then |
| Adjust_Condition (Left_Opnd (N)); |
| Adjust_Condition (Right_Opnd (N)); |
| Set_Etype (N, Standard_Boolean); |
| Adjust_Result_Type (N, Typ); |
| end if; |
| |
| Rewrite_Comparison (N); |
| |
| -- Try to narrow the operation |
| |
| if Typ = Universal_Integer and then Nkind (N) = N_Op_Ne then |
| Narrow_Large_Operation (N); |
| end if; |
| |
| -- For all cases other than elementary types, we rewrite node as the |
| -- negation of an equality operation, and reanalyze. The equality to be |
| -- used is defined in the same scope and has the same signature. This |
| -- signature must be set explicitly since in an instance it may not have |
| -- the same visibility as in the generic unit. This avoids duplicating |
| -- or factoring the complex code for record/array equality tests etc. |
| |
| -- This case is also used for the minimal expansion performed in |
| -- GNATprove mode. |
| |
| else |
| declare |
| Loc : constant Source_Ptr := Sloc (N); |
| Neg : Node_Id; |
| Ne : constant Entity_Id := Entity (N); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| Neg := |
| Make_Op_Not (Loc, |
| Right_Opnd => |
| Make_Op_Eq (Loc, |
| Left_Opnd => Left_Opnd (N), |
| Right_Opnd => Right_Opnd (N))); |
| |
| -- The level of parentheses is useless in GNATprove mode, and |
| -- bumping its level here leads to wrong columns being used in |
| -- check messages, hence skip it in this mode. |
| |
| if not GNATprove_Mode then |
| Set_Paren_Count (Right_Opnd (Neg), 1); |
| end if; |
| |
| if Scope (Ne) /= Standard_Standard then |
| Set_Entity (Right_Opnd (Neg), Corresponding_Equality (Ne)); |
| end if; |
| |
| -- For navigation purposes, we want to treat the inequality as an |
| -- implicit reference to the corresponding equality. Preserve the |
| -- Comes_From_ source flag to generate proper Xref entries. |
| |
| Preserve_Comes_From_Source (Neg, N); |
| Preserve_Comes_From_Source (Right_Opnd (Neg), N); |
| Rewrite (N, Neg); |
| Analyze_And_Resolve (N, Standard_Boolean); |
| end; |
| end if; |
| |
| -- No need for optimization in GNATprove mode, where we would rather see |
| -- the original source expression. |
| |
| if not GNATprove_Mode then |
| Optimize_Length_Comparison (N); |
| end if; |
| end Expand_N_Op_Ne; |
| |
| --------------------- |
| -- Expand_N_Op_Not -- |
| --------------------- |
| |
| -- If the argument is other than a Boolean array type, there is no special |
| -- expansion required, except for dealing with validity checks, and non- |
| -- standard boolean representations. |
| |
| -- For the packed array case, we call the special routine in Exp_Pakd, |
| -- except that if the component size is greater than one, we use the |
| -- standard routine generating a gruesome loop (it is so peculiar to have |
| -- packed arrays with non-standard Boolean representations anyway, so it |
| -- does not matter that we do not handle this case efficiently). |
| |
| -- For the unpacked array case (and for the special packed case where we |
| -- have non standard Booleans, as discussed above), we generate and insert |
| -- into the tree the following function definition: |
| |
| -- function Nnnn (A : arr) is |
| -- B : arr; |
| -- begin |
| -- for J in a'range loop |
| -- B (J) := not A (J); |
| -- end loop; |
| -- return B; |
| -- end Nnnn; |
| |
| -- or in the case of Transform_Function_Array: |
| |
| -- procedure Nnnn (A : arr; RESULT : out arr) is |
| -- begin |
| -- for J in a'range loop |
| -- RESULT (J) := not A (J); |
| -- end loop; |
| -- end Nnnn; |
| |
| -- Here arr is the actual subtype of the parameter (and hence always |
| -- constrained). Then we replace the not with a call to this subprogram. |
| |
| procedure Expand_N_Op_Not (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (Right_Opnd (N)); |
| Opnd : Node_Id; |
| Arr : Entity_Id; |
| A : Entity_Id; |
| B : Entity_Id; |
| J : Entity_Id; |
| A_J : Node_Id; |
| B_J : Node_Id; |
| |
| Func_Name : Entity_Id; |
| Loop_Statement : Node_Id; |
| |
| begin |
| Unary_Op_Validity_Checks (N); |
| |
| -- For boolean operand, deal with non-standard booleans |
| |
| if Is_Boolean_Type (Typ) then |
| Adjust_Condition (Right_Opnd (N)); |
| Set_Etype (N, Standard_Boolean); |
| Adjust_Result_Type (N, Typ); |
| return; |
| end if; |
| |
| -- Only array types need any other processing |
| |
| if not Is_Array_Type (Typ) then |
| return; |
| end if; |
| |
| -- Case of array operand. If bit packed with a component size of 1, |
| -- handle it in Exp_Pakd if the operand is known to be aligned. |
| |
| if Is_Bit_Packed_Array (Typ) |
| and then Component_Size (Typ) = 1 |
| and then not Is_Possibly_Unaligned_Object (Right_Opnd (N)) |
| then |
| Expand_Packed_Not (N); |
| return; |
| end if; |
| |
| -- Case of array operand which is not bit-packed. If the context is |
| -- a safe assignment, call in-place operation, If context is a larger |
| -- boolean expression in the context of a safe assignment, expansion is |
| -- done by enclosing operation. |
| |
| Opnd := Relocate_Node (Right_Opnd (N)); |
| Convert_To_Actual_Subtype (Opnd); |
| Arr := Etype (Opnd); |
| Ensure_Defined (Arr, N); |
| Silly_Boolean_Array_Not_Test (N, Arr); |
| |
| if Nkind (Parent (N)) = N_Assignment_Statement then |
| if Safe_In_Place_Array_Op (Name (Parent (N)), N, Empty) then |
| Build_Boolean_Array_Proc_Call (Parent (N), Opnd, Empty); |
| return; |
| |
| -- Special case the negation of a binary operation |
| |
| elsif Nkind (Opnd) in N_Op_And | N_Op_Or | N_Op_Xor |
| and then Safe_In_Place_Array_Op |
| (Name (Parent (N)), Left_Opnd (Opnd), Right_Opnd (Opnd)) |
| then |
| Build_Boolean_Array_Proc_Call (Parent (N), Opnd, Empty); |
| return; |
| end if; |
| |
| elsif Nkind (Parent (N)) in N_Binary_Op |
| and then Nkind (Parent (Parent (N))) = N_Assignment_Statement |
| then |
| declare |
| Op1 : constant Node_Id := Left_Opnd (Parent (N)); |
| Op2 : constant Node_Id := Right_Opnd (Parent (N)); |
| Lhs : constant Node_Id := Name (Parent (Parent (N))); |
| |
| begin |
| if Safe_In_Place_Array_Op (Lhs, Op1, Op2) then |
| |
| -- (not A) op (not B) can be reduced to a single call |
| |
| if N = Op1 and then Nkind (Op2) = N_Op_Not then |
| return; |
| |
| elsif N = Op2 and then Nkind (Op1) = N_Op_Not then |
| return; |
| |
| -- A xor (not B) can also be special-cased |
| |
| elsif N = Op2 and then Nkind (Parent (N)) = N_Op_Xor then |
| return; |
| end if; |
| end if; |
| end; |
| end if; |
| |
| A := Make_Defining_Identifier (Loc, Name_uA); |
| |
| if Transform_Function_Array then |
| B := Make_Defining_Identifier (Loc, Name_UP_RESULT); |
| else |
| B := Make_Defining_Identifier (Loc, Name_uB); |
| end if; |
| |
| J := Make_Defining_Identifier (Loc, Name_uJ); |
| |
| A_J := |
| Make_Indexed_Component (Loc, |
| Prefix => New_Occurrence_Of (A, Loc), |
| Expressions => New_List (New_Occurrence_Of (J, Loc))); |
| |
| B_J := |
| Make_Indexed_Component (Loc, |
| Prefix => New_Occurrence_Of (B, Loc), |
| Expressions => New_List (New_Occurrence_Of (J, Loc))); |
| |
| Loop_Statement := |
| Make_Implicit_Loop_Statement (N, |
| Identifier => Empty, |
| |
| Iteration_Scheme => |
| Make_Iteration_Scheme (Loc, |
| Loop_Parameter_Specification => |
| Make_Loop_Parameter_Specification (Loc, |
| Defining_Identifier => J, |
| Discrete_Subtype_Definition => |
| Make_Attribute_Reference (Loc, |
| Prefix => Make_Identifier (Loc, Chars (A)), |
| Attribute_Name => Name_Range))), |
| |
| Statements => New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => B_J, |
| Expression => Make_Op_Not (Loc, A_J)))); |
| |
| Func_Name := Make_Temporary (Loc, 'N'); |
| Set_Is_Inlined (Func_Name); |
| |
| if Transform_Function_Array then |
| Insert_Action (N, |
| Make_Subprogram_Body (Loc, |
| Specification => |
| Make_Procedure_Specification (Loc, |
| Defining_Unit_Name => Func_Name, |
| Parameter_Specifications => New_List ( |
| Make_Parameter_Specification (Loc, |
| Defining_Identifier => A, |
| Parameter_Type => New_Occurrence_Of (Typ, Loc)), |
| Make_Parameter_Specification (Loc, |
| Defining_Identifier => B, |
| Out_Present => True, |
| Parameter_Type => New_Occurrence_Of (Typ, Loc)))), |
| |
| Declarations => New_List, |
| |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List (Loop_Statement)))); |
| |
| declare |
| Temp_Id : constant Entity_Id := Make_Temporary (Loc, 'T'); |
| Call : Node_Id; |
| Decl : Node_Id; |
| |
| begin |
| -- Generate: |
| -- Temp : ...; |
| |
| Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp_Id, |
| Object_Definition => New_Occurrence_Of (Typ, Loc)); |
| |
| -- Generate: |
| -- Proc_Call (Opnd, Temp); |
| |
| Call := |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (Func_Name, Loc), |
| Parameter_Associations => |
| New_List (Opnd, New_Occurrence_Of (Temp_Id, Loc))); |
| |
| Insert_Actions (Parent (N), New_List (Decl, Call)); |
| Rewrite (N, New_Occurrence_Of (Temp_Id, Loc)); |
| end; |
| else |
| Insert_Action (N, |
| Make_Subprogram_Body (Loc, |
| Specification => |
| Make_Function_Specification (Loc, |
| Defining_Unit_Name => Func_Name, |
| Parameter_Specifications => New_List ( |
| Make_Parameter_Specification (Loc, |
| Defining_Identifier => A, |
| Parameter_Type => New_Occurrence_Of (Typ, Loc))), |
| Result_Definition => New_Occurrence_Of (Typ, Loc)), |
| |
| Declarations => New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => B, |
| Object_Definition => New_Occurrence_Of (Arr, Loc))), |
| |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List ( |
| Loop_Statement, |
| Make_Simple_Return_Statement (Loc, |
| Expression => Make_Identifier (Loc, Chars (B))))))); |
| |
| Rewrite (N, |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Func_Name, Loc), |
| Parameter_Associations => New_List (Opnd))); |
| end if; |
| |
| Analyze_And_Resolve (N, Typ); |
| end Expand_N_Op_Not; |
| |
| -------------------- |
| -- Expand_N_Op_Or -- |
| -------------------- |
| |
| procedure Expand_N_Op_Or (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| if Is_Array_Type (Etype (N)) then |
| Expand_Boolean_Operator (N); |
| |
| elsif Is_Boolean_Type (Etype (N)) then |
| Adjust_Condition (Left_Opnd (N)); |
| Adjust_Condition (Right_Opnd (N)); |
| Set_Etype (N, Standard_Boolean); |
| Adjust_Result_Type (N, Typ); |
| |
| elsif Is_Intrinsic_Subprogram (Entity (N)) then |
| Expand_Intrinsic_Call (N, Entity (N)); |
| end if; |
| |
| Expand_Nonbinary_Modular_Op (N); |
| end Expand_N_Op_Or; |
| |
| ---------------------- |
| -- Expand_N_Op_Plus -- |
| ---------------------- |
| |
| procedure Expand_N_Op_Plus (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| |
| begin |
| Unary_Op_Validity_Checks (N); |
| |
| -- Check for MINIMIZED/ELIMINATED overflow mode |
| |
| if Minimized_Eliminated_Overflow_Check (N) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- Try to narrow the operation |
| |
| if Typ = Universal_Integer then |
| Narrow_Large_Operation (N); |
| end if; |
| end Expand_N_Op_Plus; |
| |
| --------------------- |
| -- Expand_N_Op_Rem -- |
| --------------------- |
| |
| procedure Expand_N_Op_Rem (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| |
| Left : Node_Id; |
| Right : Node_Id; |
| |
| Lo : Uint; |
| Hi : Uint; |
| OK : Boolean; |
| |
| Lneg : Boolean; |
| Rneg : Boolean; |
| -- Set if corresponding operand can be negative |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- Check for MINIMIZED/ELIMINATED overflow mode |
| |
| if Minimized_Eliminated_Overflow_Check (N) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- Try to narrow the operation |
| |
| if Typ = Universal_Integer then |
| Narrow_Large_Operation (N); |
| |
| if Nkind (N) /= N_Op_Rem then |
| return; |
| end if; |
| end if; |
| |
| if Is_Integer_Type (Etype (N)) then |
| Apply_Divide_Checks (N); |
| |
| -- All done if we don't have a REM any more, which can happen as a |
| -- result of overflow expansion in MINIMIZED or ELIMINATED modes. |
| |
| if Nkind (N) /= N_Op_Rem then |
| return; |
| end if; |
| end if; |
| |
| -- Proceed with expansion of REM |
| |
| Left := Left_Opnd (N); |
| Right := Right_Opnd (N); |
| |
| -- Apply optimization x rem 1 = 0. We don't really need that with gcc, |
| -- but it is useful with other back ends, and is certainly harmless. |
| |
| if Is_Integer_Type (Etype (N)) |
| and then Compile_Time_Known_Value (Right) |
| and then Expr_Value (Right) = Uint_1 |
| then |
| -- Call Remove_Side_Effects to ensure that any side effects in the |
| -- ignored left operand (in particular function calls to user defined |
| -- functions) are properly executed. |
| |
| Remove_Side_Effects (Left); |
| |
| Rewrite (N, Make_Integer_Literal (Loc, 0)); |
| Analyze_And_Resolve (N, Typ); |
| return; |
| end if; |
| |
| -- Deal with annoying case of largest negative number remainder minus |
| -- one. Gigi may not handle this case correctly, because on some |
| -- targets, the mod value is computed using a divide instruction |
| -- which gives an overflow trap for this case. |
| |
| -- It would be a bit more efficient to figure out which targets this |
| -- is really needed for, but in practice it is reasonable to do the |
| -- following special check in all cases, since it means we get a clearer |
| -- message, and also the overhead is minimal given that division is |
| -- expensive in any case. |
| |
| -- In fact the check is quite easy, if the right operand is -1, then |
| -- the remainder is always 0, and we can just ignore the left operand |
| -- completely in this case. |
| |
| Determine_Range (Right, OK, Lo, Hi, Assume_Valid => True); |
| Lneg := (not OK) or else Lo < 0; |
| |
| Determine_Range (Left, OK, Lo, Hi, Assume_Valid => True); |
| Rneg := (not OK) or else Lo < 0; |
| |
| -- We won't mess with trying to find out if the left operand can really |
| -- be the largest negative number (that's a pain in the case of private |
| -- types and this is really marginal). We will just assume that we need |
| -- the test if the left operand can be negative at all. |
| |
| if (Lneg and Rneg) |
| and then not CodePeer_Mode |
| then |
| Rewrite (N, |
| Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Make_Op_Eq (Loc, |
| Left_Opnd => Duplicate_Subexpr (Right), |
| Right_Opnd => |
| Unchecked_Convert_To (Typ, Make_Integer_Literal (Loc, -1))), |
| |
| Unchecked_Convert_To (Typ, |
| Make_Integer_Literal (Loc, Uint_0)), |
| |
| Relocate_Node (N)))); |
| |
| Set_Analyzed (Next (Next (First (Expressions (N))))); |
| Analyze_And_Resolve (N, Typ); |
| end if; |
| end Expand_N_Op_Rem; |
| |
| ----------------------------- |
| -- Expand_N_Op_Rotate_Left -- |
| ----------------------------- |
| |
| procedure Expand_N_Op_Rotate_Left (N : Node_Id) is |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- If we are in Modify_Tree_For_C mode, there is no rotate left in C, |
| -- so we rewrite in terms of logical shifts |
| |
| -- Shift_Left (Num, Bits) or Shift_Right (num, Esize - Bits) |
| |
| -- where Bits is the shift count mod Esize (the mod operation here |
| -- deals with ludicrous large shift counts, which are apparently OK). |
| |
| if Modify_Tree_For_C then |
| declare |
| Loc : constant Source_Ptr := Sloc (N); |
| Rtp : constant Entity_Id := Etype (Right_Opnd (N)); |
| Typ : constant Entity_Id := Etype (N); |
| |
| begin |
| -- Sem_Intr should prevent getting there with a non binary modulus |
| |
| pragma Assert (not Non_Binary_Modulus (Typ)); |
| |
| Rewrite (Right_Opnd (N), |
| Make_Op_Rem (Loc, |
| Left_Opnd => Relocate_Node (Right_Opnd (N)), |
| Right_Opnd => Make_Integer_Literal (Loc, Esize (Typ)))); |
| |
| Analyze_And_Resolve (Right_Opnd (N), Rtp); |
| |
| Rewrite (N, |
| Make_Op_Or (Loc, |
| Left_Opnd => |
| Make_Op_Shift_Left (Loc, |
| Left_Opnd => Left_Opnd (N), |
| Right_Opnd => Right_Opnd (N)), |
| |
| Right_Opnd => |
| Make_Op_Shift_Right (Loc, |
| Left_Opnd => Duplicate_Subexpr_No_Checks (Left_Opnd (N)), |
| Right_Opnd => |
| Make_Op_Subtract (Loc, |
| Left_Opnd => Make_Integer_Literal (Loc, Esize (Typ)), |
| Right_Opnd => |
| Duplicate_Subexpr_No_Checks (Right_Opnd (N)))))); |
| |
| Analyze_And_Resolve (N, Typ); |
| end; |
| end if; |
| end Expand_N_Op_Rotate_Left; |
| |
| ------------------------------ |
| -- Expand_N_Op_Rotate_Right -- |
| ------------------------------ |
| |
| procedure Expand_N_Op_Rotate_Right (N : Node_Id) is |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- If we are in Modify_Tree_For_C mode, there is no rotate right in C, |
| -- so we rewrite in terms of logical shifts |
| |
| -- Shift_Right (Num, Bits) or Shift_Left (num, Esize - Bits) |
| |
| -- where Bits is the shift count mod Esize (the mod operation here |
| -- deals with ludicrous large shift counts, which are apparently OK). |
| |
| if Modify_Tree_For_C then |
| declare |
| Loc : constant Source_Ptr := Sloc (N); |
| Rtp : constant Entity_Id := Etype (Right_Opnd (N)); |
| Typ : constant Entity_Id := Etype (N); |
| |
| begin |
| -- Sem_Intr should prevent getting there with a non binary modulus |
| |
| pragma Assert (not Non_Binary_Modulus (Typ)); |
| |
| Rewrite (Right_Opnd (N), |
| Make_Op_Rem (Loc, |
| Left_Opnd => Relocate_Node (Right_Opnd (N)), |
| Right_Opnd => Make_Integer_Literal (Loc, Esize (Typ)))); |
| |
| Analyze_And_Resolve (Right_Opnd (N), Rtp); |
| |
| Rewrite (N, |
| Make_Op_Or (Loc, |
| Left_Opnd => |
| Make_Op_Shift_Right (Loc, |
| Left_Opnd => Left_Opnd (N), |
| Right_Opnd => Right_Opnd (N)), |
| |
| Right_Opnd => |
| Make_Op_Shift_Left (Loc, |
| Left_Opnd => Duplicate_Subexpr_No_Checks (Left_Opnd (N)), |
| Right_Opnd => |
| Make_Op_Subtract (Loc, |
| Left_Opnd => Make_Integer_Literal (Loc, Esize (Typ)), |
| Right_Opnd => |
| Duplicate_Subexpr_No_Checks (Right_Opnd (N)))))); |
| |
| Analyze_And_Resolve (N, Typ); |
| end; |
| end if; |
| end Expand_N_Op_Rotate_Right; |
| |
| ---------------------------- |
| -- Expand_N_Op_Shift_Left -- |
| ---------------------------- |
| |
| -- Note: nothing in this routine depends on left as opposed to right shifts |
| -- so we share the routine for expanding shift right operations. |
| |
| procedure Expand_N_Op_Shift_Left (N : Node_Id) is |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- If we are in Modify_Tree_For_C mode, then ensure that the right |
| -- operand is not greater than the word size (since that would not |
| -- be defined properly by the corresponding C shift operator). |
| |
| if Modify_Tree_For_C then |
| declare |
| Right : constant Node_Id := Right_Opnd (N); |
| Loc : constant Source_Ptr := Sloc (Right); |
| Typ : constant Entity_Id := Etype (N); |
| Siz : constant Uint := Esize (Typ); |
| Orig : Node_Id; |
| OK : Boolean; |
| Lo : Uint; |
| Hi : Uint; |
| |
| begin |
| -- Sem_Intr should prevent getting there with a non binary modulus |
| |
| pragma Assert (not Non_Binary_Modulus (Typ)); |
| |
| if Compile_Time_Known_Value (Right) then |
| if Expr_Value (Right) >= Siz then |
| Rewrite (N, Make_Integer_Literal (Loc, 0)); |
| Analyze_And_Resolve (N, Typ); |
| end if; |
| |
| -- Not compile time known, find range |
| |
| else |
| Determine_Range (Right, OK, Lo, Hi, Assume_Valid => True); |
| |
| -- Nothing to do if known to be OK range, otherwise expand |
| |
| if not OK or else Hi >= Siz then |
| |
| -- Prevent recursion on copy of shift node |
| |
| Orig := Relocate_Node (N); |
| Set_Analyzed (Orig); |
| |
| -- Now do the rewrite |
| |
| Rewrite (N, |
| Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Make_Op_Ge (Loc, |
| Left_Opnd => Duplicate_Subexpr_Move_Checks (Right), |
| Right_Opnd => Make_Integer_Literal (Loc, Siz)), |
| Make_Integer_Literal (Loc, 0), |
| Orig))); |
| Analyze_And_Resolve (N, Typ); |
| end if; |
| end if; |
| end; |
| end if; |
| end Expand_N_Op_Shift_Left; |
| |
| ----------------------------- |
| -- Expand_N_Op_Shift_Right -- |
| ----------------------------- |
| |
| procedure Expand_N_Op_Shift_Right (N : Node_Id) is |
| begin |
| -- Share shift left circuit |
| |
| Expand_N_Op_Shift_Left (N); |
| end Expand_N_Op_Shift_Right; |
| |
| ---------------------------------------- |
| -- Expand_N_Op_Shift_Right_Arithmetic -- |
| ---------------------------------------- |
| |
| procedure Expand_N_Op_Shift_Right_Arithmetic (N : Node_Id) is |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- If we are in Modify_Tree_For_C mode, there is no shift right |
| -- arithmetic in C, so we rewrite in terms of logical shifts for |
| -- modular integers, and keep the Shift_Right intrinsic for signed |
| -- integers: even though doing a shift on a signed integer is not |
| -- fully guaranteed by the C standard, this is what C compilers |
| -- implement in practice. |
| -- Consider also taking advantage of this for modular integers by first |
| -- performing an unchecked conversion of the modular integer to a signed |
| -- integer of the same sign, and then convert back. |
| |
| -- Shift_Right (Num, Bits) or |
| -- (if Num >= Sign |
| -- then not (Shift_Right (Mask, bits)) |
| -- else 0) |
| |
| -- Here Mask is all 1 bits (2**size - 1), and Sign is 2**(size - 1) |
| |
| -- Note: the above works fine for shift counts greater than or equal |
| -- to the word size, since in this case (not (Shift_Right (Mask, bits))) |
| -- generates all 1'bits. |
| |
| if Modify_Tree_For_C and then Is_Modular_Integer_Type (Etype (N)) then |
| declare |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| Sign : constant Uint := 2 ** (Esize (Typ) - 1); |
| Mask : constant Uint := (2 ** Esize (Typ)) - 1; |
| Left : constant Node_Id := Left_Opnd (N); |
| Right : constant Node_Id := Right_Opnd (N); |
| Maskx : Node_Id; |
| |
| begin |
| -- Sem_Intr should prevent getting there with a non binary modulus |
| |
| pragma Assert (not Non_Binary_Modulus (Typ)); |
| |
| -- Here if not (Shift_Right (Mask, bits)) can be computed at |
| -- compile time as a single constant. |
| |
| if Compile_Time_Known_Value (Right) then |
| declare |
| Val : constant Uint := Expr_Value (Right); |
| |
| begin |
| if Val >= Esize (Typ) then |
| Maskx := Make_Integer_Literal (Loc, Mask); |
| |
| else |
| Maskx := |
| Make_Integer_Literal (Loc, |
| Intval => Mask - (Mask / (2 ** Expr_Value (Right)))); |
| end if; |
| end; |
| |
| else |
| Maskx := |
| Make_Op_Not (Loc, |
| Right_Opnd => |
| Make_Op_Shift_Right (Loc, |
| Left_Opnd => Make_Integer_Literal (Loc, Mask), |
| Right_Opnd => Duplicate_Subexpr_No_Checks (Right))); |
| end if; |
| |
| -- Now do the rewrite |
| |
| Rewrite (N, |
| Make_Op_Or (Loc, |
| Left_Opnd => |
| Make_Op_Shift_Right (Loc, |
| Left_Opnd => Left, |
| Right_Opnd => Right), |
| Right_Opnd => |
| Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Make_Op_Ge (Loc, |
| Left_Opnd => Duplicate_Subexpr_No_Checks (Left), |
| Right_Opnd => Make_Integer_Literal (Loc, Sign)), |
| Maskx, |
| Make_Integer_Literal (Loc, 0))))); |
| Analyze_And_Resolve (N, Typ); |
| end; |
| end if; |
| end Expand_N_Op_Shift_Right_Arithmetic; |
| |
| -------------------------- |
| -- Expand_N_Op_Subtract -- |
| -------------------------- |
| |
| procedure Expand_N_Op_Subtract (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| -- Check for MINIMIZED/ELIMINATED overflow mode |
| |
| if Minimized_Eliminated_Overflow_Check (N) then |
| Apply_Arithmetic_Overflow_Check (N); |
| return; |
| end if; |
| |
| -- Try to narrow the operation |
| |
| if Typ = Universal_Integer then |
| Narrow_Large_Operation (N); |
| |
| if Nkind (N) /= N_Op_Subtract then |
| return; |
| end if; |
| end if; |
| |
| -- N - 0 = N for integer types |
| |
| if Is_Integer_Type (Typ) |
| and then Compile_Time_Known_Value (Right_Opnd (N)) |
| and then Expr_Value (Right_Opnd (N)) = 0 |
| then |
| Rewrite (N, Left_Opnd (N)); |
| return; |
| end if; |
| |
| -- Arithmetic overflow checks for signed integer/fixed point types |
| |
| if Is_Signed_Integer_Type (Typ) or else Is_Fixed_Point_Type (Typ) then |
| Apply_Arithmetic_Overflow_Check (N); |
| end if; |
| |
| -- Overflow checks for floating-point if -gnateF mode active |
| |
| Check_Float_Op_Overflow (N); |
| |
| Expand_Nonbinary_Modular_Op (N); |
| end Expand_N_Op_Subtract; |
| |
| --------------------- |
| -- Expand_N_Op_Xor -- |
| --------------------- |
| |
| procedure Expand_N_Op_Xor (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| |
| begin |
| Binary_Op_Validity_Checks (N); |
| |
| if Is_Array_Type (Etype (N)) then |
| Expand_Boolean_Operator (N); |
| |
| elsif Is_Boolean_Type (Etype (N)) then |
| Adjust_Condition (Left_Opnd (N)); |
| Adjust_Condition (Right_Opnd (N)); |
| Set_Etype (N, Standard_Boolean); |
| Adjust_Result_Type (N, Typ); |
| |
| elsif Is_Intrinsic_Subprogram (Entity (N)) then |
| Expand_Intrinsic_Call (N, Entity (N)); |
| end if; |
| |
| Expand_Nonbinary_Modular_Op (N); |
| end Expand_N_Op_Xor; |
| |
| ---------------------- |
| -- Expand_N_Or_Else -- |
| ---------------------- |
| |
| procedure Expand_N_Or_Else (N : Node_Id) |
| renames Expand_Short_Circuit_Operator; |
| |
| ----------------------------------- |
| -- Expand_N_Qualified_Expression -- |
| ----------------------------------- |
| |
| procedure Expand_N_Qualified_Expression (N : Node_Id) is |
| Operand : constant Node_Id := Expression (N); |
| Target_Type : constant Entity_Id := Entity (Subtype_Mark (N)); |
| |
| begin |
| -- Do validity check if validity checking operands |
| |
| if Validity_Checks_On and Validity_Check_Operands then |
| Ensure_Valid (Operand); |
| end if; |
| |
| Freeze_Before (Operand, Target_Type); |
| |
| -- Apply possible constraint check |
| |
| Apply_Constraint_Check (Operand, Target_Type, No_Sliding => True); |
| |
| -- Apply possible predicate check |
| |
| Apply_Predicate_Check (Operand, Target_Type); |
| |
| if Do_Range_Check (Operand) then |
| Generate_Range_Check (Operand, Target_Type, CE_Range_Check_Failed); |
| end if; |
| end Expand_N_Qualified_Expression; |
| |
| ------------------------------------ |
| -- Expand_N_Quantified_Expression -- |
| ------------------------------------ |
| |
| -- We expand: |
| |
| -- for all X in range => Cond |
| |
| -- into: |
| |
| -- T := True; |
| -- for X in range loop |
| -- if not Cond then |
| -- T := False; |
| -- exit; |
| -- end if; |
| -- end loop; |
| |
| -- Similarly, an existentially quantified expression: |
| |
| -- for some X in range => Cond |
| |
| -- becomes: |
| |
| -- T := False; |
| -- for X in range loop |
| -- if Cond then |
| -- T := True; |
| -- exit; |
| -- end if; |
| -- end loop; |
| |
| -- In both cases, the iteration may be over a container in which case it is |
| -- given by an iterator specification, not a loop parameter specification. |
| |
| procedure Expand_N_Quantified_Expression (N : Node_Id) is |
| Actions : constant List_Id := New_List; |
| For_All : constant Boolean := All_Present (N); |
| Iter_Spec : constant Node_Id := Iterator_Specification (N); |
| Loc : constant Source_Ptr := Sloc (N); |
| Loop_Spec : constant Node_Id := Loop_Parameter_Specification (N); |
| Cond : Node_Id; |
| Flag : Entity_Id; |
| Scheme : Node_Id; |
| Stmts : List_Id; |
| Var : Entity_Id; |
| |
| begin |
| -- Ensure that the bound variable as well as the type of Name of the |
| -- Iter_Spec if present are properly frozen. We must do this before |
| -- expansion because the expression is about to be converted into a |
| -- loop, and resulting freeze nodes may end up in the wrong place in the |
| -- tree. |
| |
| if Present (Iter_Spec) then |
| Var := Defining_Identifier (Iter_Spec); |
| else |
| Var := Defining_Identifier (Loop_Spec); |
| end if; |
| |
| declare |
| P : Node_Id := Parent (N); |
| begin |
| while Nkind (P) in N_Subexpr loop |
| P := Parent (P); |
| end loop; |
| |
| if Present (Iter_Spec) then |
| Freeze_Before (P, Etype (Name (Iter_Spec))); |
| end if; |
| |
| Freeze_Before (P, Etype (Var)); |
| end; |
| |
| -- Create the declaration of the flag which tracks the status of the |
| -- quantified expression. Generate: |
| |
| -- Flag : Boolean := (True | False); |
| |
| Flag := Make_Temporary (Loc, 'T', N); |
| |
| Append_To (Actions, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Flag, |
| Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc), |
| Expression => |
| New_Occurrence_Of (Boolean_Literals (For_All), Loc))); |
| |
| -- Construct the circuitry which tracks the status of the quantified |
| -- expression. Generate: |
| |
| -- if [not] Cond then |
| -- Flag := (False | True); |
| -- exit; |
| -- end if; |
| |
| Cond := Relocate_Node (Condition (N)); |
| |
| if For_All then |
| Cond := Make_Op_Not (Loc, Cond); |
| end if; |
| |
| Stmts := New_List ( |
| Make_Implicit_If_Statement (N, |
| Condition => Cond, |
| Then_Statements => New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Flag, Loc), |
| Expression => |
| New_Occurrence_Of (Boolean_Literals (not For_All), Loc)), |
| Make_Exit_Statement (Loc)))); |
| |
| -- Build the loop equivalent of the quantified expression |
| |
| if Present (Iter_Spec) then |
| Scheme := |
| Make_Iteration_Scheme (Loc, |
| Iterator_Specification => Iter_Spec); |
| else |
| Scheme := |
| Make_Iteration_Scheme (Loc, |
| Loop_Parameter_Specification => Loop_Spec); |
| end if; |
| |
| Append_To (Actions, |
| Make_Loop_Statement (Loc, |
| Iteration_Scheme => Scheme, |
| Statements => Stmts, |
| End_Label => Empty)); |
| |
| -- Transform the quantified expression |
| |
| Rewrite (N, |
| Make_Expression_With_Actions (Loc, |
| Expression => New_Occurrence_Of (Flag, Loc), |
| Actions => Actions)); |
| Analyze_And_Resolve (N, Standard_Boolean); |
| end Expand_N_Quantified_Expression; |
| |
| --------------------------------- |
| -- Expand_N_Selected_Component -- |
| --------------------------------- |
| |
| procedure Expand_N_Selected_Component (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Par : constant Node_Id := Parent (N); |
| P : constant Node_Id := Prefix (N); |
| S : constant Node_Id := Selector_Name (N); |
| Ptyp : constant Entity_Id := Underlying_Type (Etype (P)); |
| Disc : Entity_Id; |
| New_N : Node_Id; |
| Dcon : Elmt_Id; |
| Dval : Node_Id; |
| |
| function In_Left_Hand_Side (Comp : Node_Id) return Boolean; |
| -- Gigi needs a temporary for prefixes that depend on a discriminant, |
| -- unless the context of an assignment can provide size information. |
| -- Don't we have a general routine that does this??? |
| |
| function Is_Subtype_Declaration return Boolean; |
| -- The replacement of a discriminant reference by its value is required |
| -- if this is part of the initialization of an temporary generated by a |
| -- change of representation. This shows up as the construction of a |
| -- discriminant constraint for a subtype declared at the same point as |
| -- the entity in the prefix of the selected component. We recognize this |
| -- case when the context of the reference is: |
| -- subtype ST is T(Obj.D); |
| -- where the entity for Obj comes from source, and ST has the same sloc. |
| |
| ----------------------- |
| -- In_Left_Hand_Side -- |
| ----------------------- |
| |
| function In_Left_Hand_Side (Comp : Node_Id) return Boolean is |
| begin |
| return (Nkind (Parent (Comp)) = N_Assignment_Statement |
| and then Comp = Name (Parent (Comp))) |
| or else (Present (Parent (Comp)) |
| and then Nkind (Parent (Comp)) in N_Subexpr |
| and then In_Left_Hand_Side (Parent (Comp))); |
| end In_Left_Hand_Side; |
| |
| ----------------------------- |
| -- Is_Subtype_Declaration -- |
| ----------------------------- |
| |
| function Is_Subtype_Declaration return Boolean is |
| Par : constant Node_Id := Parent (N); |
| begin |
| return |
| Nkind (Par) = N_Index_Or_Discriminant_Constraint |
| and then Nkind (Parent (Parent (Par))) = N_Subtype_Declaration |
| and then Comes_From_Source (Entity (Prefix (N))) |
| and then Sloc (Par) = Sloc (Entity (Prefix (N))); |
| end Is_Subtype_Declaration; |
| |
| -- Start of processing for Expand_N_Selected_Component |
| |
| begin |
| -- Deal with discriminant check required |
| |
| if Do_Discriminant_Check (N) then |
| if Present (Discriminant_Checking_Func |
| (Original_Record_Component (Entity (S)))) |
| then |
| -- Present the discriminant checking function to the backend, so |
| -- that it can inline the call to the function. |
| |
| Add_Inlined_Body |
| (Discriminant_Checking_Func |
| (Original_Record_Component (Entity (S))), |
| N); |
| |
| -- Now reset the flag and generate the call |
| |
| Set_Do_Discriminant_Check (N, False); |
| Generate_Discriminant_Check (N); |
| |
| -- In the case of Unchecked_Union, no discriminant checking is |
| -- actually performed. |
| |
| else |
| if (not Is_Unchecked_Union |
| (Implementation_Base_Type (Etype (Prefix (N))))) |
| and then not Is_Predefined_Unit (Get_Source_Unit (N)) |
| then |
| Error_Msg_N |
| ("sorry - unable to generate discriminant check for" & |
| " reference to variant component &", |
| Selector_Name (N)); |
| end if; |
| |
| Set_Do_Discriminant_Check (N, False); |
| end if; |
| end if; |
| |
| -- Ada 2005 (AI-318-02): If the prefix is a call to a build-in-place |
| -- function, then additional actuals must be passed. |
| |
| if Is_Build_In_Place_Function_Call (P) then |
| Make_Build_In_Place_Call_In_Anonymous_Context (P); |
| |
| -- Ada 2005 (AI-318-02): Specialization of the previous case for prefix |
| -- containing build-in-place function calls whose returned object covers |
| -- interface types. |
| |
| elsif Present (Unqual_BIP_Iface_Function_Call (P)) then |
| Make_Build_In_Place_Iface_Call_In_Anonymous_Context (P); |
| end if; |
| |
| -- Gigi cannot handle unchecked conversions that are the prefix of a |
| -- selected component with discriminants. This must be checked during |
| -- expansion, because during analysis the type of the selector is not |
| -- known at the point the prefix is analyzed. If the conversion is the |
| -- target of an assignment, then we cannot force the evaluation. |
| |
| if Nkind (Prefix (N)) = N_Unchecked_Type_Conversion |
| and then Has_Discriminants (Etype (N)) |
| and then not In_Left_Hand_Side (N) |
| then |
| Force_Evaluation (Prefix (N)); |
| end if; |
| |
| -- Remaining processing applies only if selector is a discriminant |
| |
| if Ekind (Entity (Selector_Name (N))) = E_Discriminant then |
| |
| -- If the selector is a discriminant of a constrained record type, |
| -- we may be able to rewrite the expression with the actual value |
| -- of the discriminant, a useful optimization in some cases. |
| |
| if Is_Record_Type (Ptyp) |
| and then Has_Discriminants (Ptyp) |
| and then Is_Constrained (Ptyp) |
| then |
| -- Do this optimization for discrete types only, and not for |
| -- access types (access discriminants get us into trouble). |
| |
| if not Is_Discrete_Type (Etype (N)) then |
| null; |
| |
| -- Don't do this on the left-hand side of an assignment statement. |
| -- Normally one would think that references like this would not |
| -- occur, but they do in generated code, and mean that we really |
| -- do want to assign the discriminant. |
| |
| elsif Nkind (Par) = N_Assignment_Statement |
| and then Name (Par) = N |
| then |
| null; |
| |
| -- Don't do this optimization for the prefix of an attribute or |
| -- the name of an object renaming declaration since these are |
| -- contexts where we do not want the value anyway. |
| |
| elsif (Nkind (Par) = N_Attribute_Reference |
| and then Prefix (Par) = N) |
| or else Is_Renamed_Object (N) |
| then |
| null; |
| |
| -- Don't do this optimization if we are within the code for a |
| -- discriminant check, since the whole point of such a check may |
| -- be to verify the condition on which the code below depends. |
| |
| elsif Is_In_Discriminant_Check (N) then |
| null; |
| |
| -- Green light to see if we can do the optimization. There is |
| -- still one condition that inhibits the optimization below but |
| -- now is the time to check the particular discriminant. |
| |
| else |
| -- Loop through discriminants to find the matching discriminant |
| -- constraint to see if we can copy it. |
| |
| Disc := First_Discriminant (Ptyp); |
| Dcon := First_Elmt (Discriminant_Constraint (Ptyp)); |
| Discr_Loop : while Present (Dcon) loop |
| Dval := Node (Dcon); |
| |
| -- Check if this is the matching discriminant and if the |
| -- discriminant value is simple enough to make sense to |
| -- copy. We don't want to copy complex expressions, and |
| -- indeed to do so can cause trouble (before we put in |
| -- this guard, a discriminant expression containing an |
| -- AND THEN was copied, causing problems for coverage |
| -- analysis tools). |
| |
| -- However, if the reference is part of the initialization |
| -- code generated for an object declaration, we must use |
| -- the discriminant value from the subtype constraint, |
| -- because the selected component may be a reference to the |
| -- object being initialized, whose discriminant is not yet |
| -- set. This only happens in complex cases involving changes |
| -- of representation. |
| |
| if Disc = Entity (Selector_Name (N)) |
| and then (Is_Entity_Name (Dval) |
| or else Compile_Time_Known_Value (Dval) |
| or else Is_Subtype_Declaration) |
| then |
| -- Here we have the matching discriminant. Check for |
| -- the case of a discriminant of a component that is |
| -- constrained by an outer discriminant, which cannot |
| -- be optimized away. |
| |
| if Denotes_Discriminant (Dval, Check_Concurrent => True) |
| then |
| exit Discr_Loop; |
| |
| -- Do not retrieve value if constraint is not static. It |
| -- is generally not useful, and the constraint may be a |
| -- rewritten outer discriminant in which case it is in |
| -- fact incorrect. |
| |
| elsif Is_Entity_Name (Dval) |
| and then |
| Nkind (Parent (Entity (Dval))) = N_Object_Declaration |
| and then Present (Expression (Parent (Entity (Dval)))) |
| and then not |
| Is_OK_Static_Expression |
| (Expression (Parent (Entity (Dval)))) |
| then |
| exit Discr_Loop; |
| |
| -- In the context of a case statement, the expression may |
| -- have the base type of the discriminant, and we need to |
| -- preserve the constraint to avoid spurious errors on |
| -- missing cases. |
| |
| elsif Nkind (Parent (N)) = N_Case_Statement |
| and then Etype (Dval) /= Etype (Disc) |
| then |
| Rewrite (N, |
| Make_Qualified_Expression (Loc, |
| Subtype_Mark => |
| New_Occurrence_Of (Etype (Disc), Loc), |
| Expression => |
| New_Copy_Tree (Dval))); |
| Analyze_And_Resolve (N, Etype (Disc)); |
| |
| -- In case that comes out as a static expression, |
| -- reset it (a selected component is never static). |
| |
| Set_Is_Static_Expression (N, False); |
| return; |
| |
| -- Otherwise we can just copy the constraint, but the |
| -- result is certainly not static. In some cases the |
| -- discriminant constraint has been analyzed in the |
| -- context of the original subtype indication, but for |
| -- itypes the constraint might not have been analyzed |
| -- yet, and this must be done now. |
| |
| else |
| Rewrite (N, New_Copy_Tree (Dval)); |
| Analyze_And_Resolve (N); |
| Set_Is_Static_Expression (N, False); |
| return; |
| end if; |
| end if; |
| |
| Next_Elmt (Dcon); |
| Next_Discriminant (Disc); |
| end loop Discr_Loop; |
| |
| -- Note: the above loop should always find a matching |
| -- discriminant, but if it does not, we just missed an |
| -- optimization due to some glitch (perhaps a previous |
| -- error), so ignore. |
| |
| end if; |
| end if; |
| |
| -- The only remaining processing is in the case of a discriminant of |
| -- a concurrent object, where we rewrite the prefix to denote the |
| -- corresponding record type. If the type is derived and has renamed |
| -- discriminants, use corresponding discriminant, which is the one |
| -- that appears in the corresponding record. |
| |
| if not Is_Concurrent_Type (Ptyp) then |
| return; |
| end if; |
| |
| Disc := Entity (Selector_Name (N)); |
| |
| if Is_Derived_Type (Ptyp) |
| and then Present (Corresponding_Discriminant (Disc)) |
| then |
| Disc := Corresponding_Discriminant (Disc); |
| end if; |
| |
| New_N := |
| Make_Selected_Component (Loc, |
| Prefix => |
| Unchecked_Convert_To (Corresponding_Record_Type (Ptyp), |
| New_Copy_Tree (P)), |
| Selector_Name => Make_Identifier (Loc, Chars (Disc))); |
| |
| Rewrite (N, New_N); |
| Analyze (N); |
| end if; |
| |
| -- Set Atomic_Sync_Required if necessary for atomic component |
| |
| if Nkind (N) = N_Selected_Component then |
| declare |
| E : constant Entity_Id := Entity (Selector_Name (N)); |
| Set : Boolean; |
| |
| begin |
| -- If component is atomic, but type is not, setting depends on |
| -- disable/enable state for the component. |
| |
| if Is_Atomic (E) and then not Is_Atomic (Etype (E)) then |
| Set := not Atomic_Synchronization_Disabled (E); |
| |
| -- If component is not atomic, but its type is atomic, setting |
| -- depends on disable/enable state for the type. |
| |
| elsif not Is_Atomic (E) and then Is_Atomic (Etype (E)) then |
| Set := not Atomic_Synchronization_Disabled (Etype (E)); |
| |
| -- If both component and type are atomic, we disable if either |
| -- component or its type have sync disabled. |
| |
| elsif Is_Atomic (E) and then Is_Atomic (Etype (E)) then |
| Set := (not Atomic_Synchronization_Disabled (E)) |
| and then |
| (not Atomic_Synchronization_Disabled (Etype (E))); |
| |
| else |
| Set := False; |
| end if; |
| |
| -- Set flag if required |
| |
| if Set then |
| Activate_Atomic_Synchronization (N); |
| end if; |
| end; |
| end if; |
| end Expand_N_Selected_Component; |
| |
| -------------------- |
| -- Expand_N_Slice -- |
| -------------------- |
| |
| procedure Expand_N_Slice (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| |
| function Is_Procedure_Actual (N : Node_Id) return Boolean; |
| -- Check whether the argument is an actual for a procedure call, in |
| -- which case the expansion of a bit-packed slice is deferred until the |
| -- call itself is expanded. The reason this is required is that we might |
| -- have an IN OUT or OUT parameter, and the copy out is essential, and |
| -- that copy out would be missed if we created a temporary here in |
| -- Expand_N_Slice. Note that we don't bother to test specifically for an |
| -- IN OUT or OUT mode parameter, since it is a bit tricky to do, and it |
| -- is harmless to defer expansion in the IN case, since the call |
| -- processing will still generate the appropriate copy in operation, |
| -- which will take care of the slice. |
| |
| procedure Make_Temporary_For_Slice; |
| -- Create a named variable for the value of the slice, in cases where |
| -- the back end cannot handle it properly, e.g. when packed types or |
| -- unaligned slices are involved. |
| |
| ------------------------- |
| -- Is_Procedure_Actual -- |
| ------------------------- |
| |
| function Is_Procedure_Actual (N : Node_Id) return Boolean is |
| Par : Node_Id := Parent (N); |
| |
| begin |
| loop |
| -- If our parent is a procedure call we can return |
| |
| if Nkind (Par) = N_Procedure_Call_Statement then |
| return True; |
| |
| -- If our parent is a type conversion, keep climbing the tree, |
| -- since a type conversion can be a procedure actual. Also keep |
| -- climbing if parameter association or a qualified expression, |
| -- since these are additional cases that do can appear on |
| -- procedure actuals. |
| |
| elsif Nkind (Par) in N_Type_Conversion |
| | N_Parameter_Association |
| | N_Qualified_Expression |
| then |
| Par := Parent (Par); |
| |
| -- Any other case is not what we are looking for |
| |
| else |
| return False; |
| end if; |
| end loop; |
| end Is_Procedure_Actual; |
| |
| ------------------------------ |
| -- Make_Temporary_For_Slice -- |
| ------------------------------ |
| |
| procedure Make_Temporary_For_Slice is |
| Ent : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
| Decl : Node_Id; |
| |
| begin |
| Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Ent, |
| Object_Definition => New_Occurrence_Of (Typ, Loc)); |
| |
| Set_No_Initialization (Decl); |
| |
| Insert_Actions (N, New_List ( |
| Decl, |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Ent, Loc), |
| Expression => Relocate_Node (N)))); |
| |
| Rewrite (N, New_Occurrence_Of (Ent, Loc)); |
| Analyze_And_Resolve (N, Typ); |
| end Make_Temporary_For_Slice; |
| |
| -- Local variables |
| |
| Pref : constant Node_Id := Prefix (N); |
| |
| -- Start of processing for Expand_N_Slice |
| |
| begin |
| -- Ada 2005 (AI-318-02): If the prefix is a call to a build-in-place |
| -- function, then additional actuals must be passed. |
| |
| if Is_Build_In_Place_Function_Call (Pref) then |
| Make_Build_In_Place_Call_In_Anonymous_Context (Pref); |
| |
| -- Ada 2005 (AI-318-02): Specialization of the previous case for prefix |
| -- containing build-in-place function calls whose returned object covers |
| -- interface types. |
| |
| elsif Present (Unqual_BIP_Iface_Function_Call (Pref)) then |
| Make_Build_In_Place_Iface_Call_In_Anonymous_Context (Pref); |
| end if; |
| |
| -- The remaining case to be handled is packed slices. We can leave |
| -- packed slices as they are in the following situations: |
| |
| -- 1. Right or left side of an assignment (we can handle this |
| -- situation correctly in the assignment statement expansion). |
| |
| -- 2. Prefix of indexed component (the slide is optimized away in this |
| -- case, see the start of Expand_N_Indexed_Component.) |
| |
| -- 3. Object renaming declaration, since we want the name of the |
| -- slice, not the value. |
| |
| -- 4. Argument to procedure call, since copy-in/copy-out handling may |
| -- be required, and this is handled in the expansion of call |
| -- itself. |
| |
| -- 5. Prefix of an address attribute (this is an error which is caught |
| -- elsewhere, and the expansion would interfere with generating the |
| -- error message) or of a size attribute (because 'Size may change |
| -- when applied to the temporary instead of the slice directly). |
| |
| if not Is_Packed (Typ) then |
| |
| -- Apply transformation for actuals of a function call, where |
| -- Expand_Actuals is not used. |
| |
| if Nkind (Parent (N)) = N_Function_Call |
| and then Is_Possibly_Unaligned_Slice (N) |
| then |
| Make_Temporary_For_Slice; |
| end if; |
| |
| elsif Nkind (Parent (N)) = N_Assignment_Statement |
| or else (Nkind (Parent (Parent (N))) = N_Assignment_Statement |
| and then Parent (N) = Name (Parent (Parent (N)))) |
| then |
| return; |
| |
| elsif Nkind (Parent (N)) = N_Indexed_Component |
| or else Is_Renamed_Object (N) |
| or else Is_Procedure_Actual (N) |
| then |
| return; |
| |
| elsif Nkind (Parent (N)) = N_Attribute_Reference |
| and then (Attribute_Name (Parent (N)) = Name_Address |
| or else Attribute_Name (Parent (N)) = Name_Size) |
| then |
| return; |
| |
| else |
| Make_Temporary_For_Slice; |
| end if; |
| end Expand_N_Slice; |
| |
| ------------------------------ |
| -- Expand_N_Type_Conversion -- |
| ------------------------------ |
| |
| procedure Expand_N_Type_Conversion (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Operand : constant Node_Id := Expression (N); |
| Operand_Acc : Node_Id := Operand; |
| Target_Type : Entity_Id := Etype (N); |
| Operand_Type : Entity_Id := Etype (Operand); |
| |
| procedure Discrete_Range_Check; |
| -- Handles generation of range check for discrete target value |
| |
| procedure Handle_Changed_Representation; |
| -- This is called in the case of record and array type conversions to |
| -- see if there is a change of representation to be handled. Change of |
| -- representation is actually handled at the assignment statement level, |
| -- and what this procedure does is rewrite node N conversion as an |
| -- assignment to temporary. If there is no change of representation, |
| -- then the conversion node is unchanged. |
| |
| procedure Raise_Accessibility_Error; |
| -- Called when we know that an accessibility check will fail. Rewrites |
| -- node N to an appropriate raise statement and outputs warning msgs. |
| -- The Etype of the raise node is set to Target_Type. Note that in this |
| -- case the rest of the processing should be skipped (i.e. the call to |
| -- this procedure will be followed by "goto Done"). |
| |
| procedure Real_Range_Check; |
| -- Handles generation of range check for real target value |
| |
| function Has_Extra_Accessibility (Id : Entity_Id) return Boolean; |
| -- True iff Present (Effective_Extra_Accessibility (Id)) successfully |
| -- evaluates to True. |
| |
| function Statically_Deeper_Relation_Applies (Targ_Typ : Entity_Id) |
| return Boolean; |
| -- Given a target type for a conversion, determine whether the |
| -- statically deeper accessibility rules apply to it. |
| |
| -------------------------- |
| -- Discrete_Range_Check -- |
| -------------------------- |
| |
| -- Case of conversions to a discrete type. We let Generate_Range_Check |
| -- do the heavy lifting, after converting a fixed-point operand to an |
| -- appropriate integer type. |
| |
| procedure Discrete_Range_Check is |
| Expr : Node_Id; |
| Ityp : Entity_Id; |
| |
| procedure Generate_Temporary; |
| -- Generate a temporary to facilitate in the C backend the code |
| -- generation of the unchecked conversion since the size of the |
| -- source type may differ from the size of the target type. |
| |
| ------------------------ |
| -- Generate_Temporary -- |
| ------------------------ |
| |
| procedure Generate_Temporary is |
| begin |
| if Esize (Etype (Expr)) < Esize (Etype (Ityp)) then |
| declare |
| Exp_Type : constant Entity_Id := Ityp; |
| Def_Id : constant Entity_Id := |
| Make_Temporary (Loc, 'R', Expr); |
| E : Node_Id; |
| Res : Node_Id; |
| |
| begin |
| Set_Is_Internal (Def_Id); |
| Set_Etype (Def_Id, Exp_Type); |
| Res := New_Occurrence_Of (Def_Id, Loc); |
| |
| E := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Def_Id, |
| Object_Definition => New_Occurrence_Of |
| (Exp_Type, Loc), |
| Constant_Present => True, |
| Expression => Relocate_Node (Expr)); |
| |
| Set_Assignment_OK (E); |
| Insert_Action (Expr, E); |
| |
| Set_Assignment_OK (Res, Assignment_OK (Expr)); |
| |
| Rewrite (Expr, Res); |
| Analyze_And_Resolve (Expr, Exp_Type); |
| end; |
| end if; |
| end Generate_Temporary; |
| |
| -- Start of processing for Discrete_Range_Check |
| |
| begin |
| -- Nothing more to do if conversion was rewritten |
| |
| if Nkind (N) /= N_Type_Conversion then |
| return; |
| end if; |
| |
| Expr := Expression (N); |
| |
| -- Clear the Do_Range_Check flag on Expr |
| |
| Set_Do_Range_Check (Expr, False); |
| |
| -- Nothing to do if range checks suppressed |
| |
| if Range_Checks_Suppressed (Target_Type) then |
| return; |
| end if; |
| |
| -- Nothing to do if expression is an entity on which checks have been |
| -- suppressed. |
| |
| if Is_Entity_Name (Expr) |
| and then Range_Checks_Suppressed (Entity (Expr)) |
| then |
| return; |
| end if; |
| |
| -- Before we do a range check, we have to deal with treating |
| -- a fixed-point operand as an integer. The way we do this |
| -- is simply to do an unchecked conversion to an appropriate |
| -- integer type with the smallest size, so that we can suppress |
| -- trivial checks. |
| |
| if Is_Fixed_Point_Type (Etype (Expr)) then |
| Ityp := Small_Integer_Type_For |
| (Esize (Base_Type (Etype (Expr))), False); |
| |
| -- Generate a temporary with the integer type to facilitate in the |
| -- C backend the code generation for the unchecked conversion. |
| |
| if Modify_Tree_For_C then |
| Generate_Temporary; |
| end if; |
| |
| Rewrite (Expr, Unchecked_Convert_To (Ityp, Expr)); |
| end if; |
| |
| -- Reset overflow flag, since the range check will include |
| -- dealing with possible overflow, and generate the check. |
| |
| Set_Do_Overflow_Check (N, False); |
| |
| Generate_Range_Check (Expr, Target_Type, CE_Range_Check_Failed); |
| end Discrete_Range_Check; |
| |
| ----------------------------------- |
| -- Handle_Changed_Representation -- |
| ----------------------------------- |
| |
| procedure Handle_Changed_Representation is |
| Temp : Entity_Id; |
| Decl : Node_Id; |
| Odef : Node_Id; |
| N_Ix : Node_Id; |
| Cons : List_Id; |
| |
| begin |
| -- Nothing else to do if no change of representation |
| |
| if Has_Compatible_Representation (Target_Type, Operand_Type) then |
| return; |
| |
| -- The real change of representation work is done by the assignment |
| -- statement processing. So if this type conversion is appearing as |
| -- the expression of an assignment statement, nothing needs to be |
| -- done to the conversion. |
| |
| elsif Nkind (Parent (N)) = N_Assignment_Statement then |
| return; |
| |
| -- Otherwise we need to generate a temporary variable, and do the |
| -- change of representation assignment into that temporary variable. |
| -- The conversion is then replaced by a reference to this variable. |
| |
| else |
| Cons := No_List; |
| |
| -- If type is unconstrained we have to add a constraint, copied |
| -- from the actual value of the left-hand side. |
| |
| if not Is_Constrained (Target_Type) then |
| if Has_Discriminants (Operand_Type) then |
| |
| -- A change of representation can only apply to untagged |
| -- types. We need to build the constraint that applies to |
| -- the target type, using the constraints of the operand. |
| -- The analysis is complicated if there are both inherited |
| -- discriminants and constrained discriminants. |
| -- We iterate over the discriminants of the target, and |
| -- find the discriminant of the same name: |
| |
| -- a) If there is a corresponding discriminant in the object |
| -- then the value is a selected component of the operand. |
| |
| -- b) Otherwise the value of a constrained discriminant is |
| -- found in the stored constraint of the operand. |
| |
| declare |
| Stored : constant Elist_Id := |
| Stored_Constraint (Operand_Type); |
| -- Stored constraints of the operand. If present, they |
| -- correspond to the discriminants of the parent type. |
| |
| Disc_O : Entity_Id; |
| -- Discriminant of the operand type. Its value in the |
| -- object is captured in a selected component. |
| |
| Disc_T : Entity_Id; |
| -- Discriminant of the target type |
| |
| Elmt : Elmt_Id; |
| |
| begin |
| Disc_O := First_Discriminant (Operand_Type); |
| Disc_T := First_Discriminant (Target_Type); |
| Elmt := (if Present (Stored) |
| then First_Elmt (Stored) |
| else No_Elmt); |
| |
| Cons := New_List; |
| while Present (Disc_T) loop |
| if Present (Disc_O) |
| and then Chars (Disc_T) = Chars (Disc_O) |
| then |
| Append_To (Cons, |
| Make_Selected_Component (Loc, |
| Prefix => |
| Duplicate_Subexpr_Move_Checks (Operand), |
| Selector_Name => |
| Make_Identifier (Loc, Chars (Disc_O)))); |
| Next_Discriminant (Disc_O); |
| |
| elsif Present (Elmt) then |
| Append_To (Cons, New_Copy_Tree (Node (Elmt))); |
| end if; |
| |
| if Present (Elmt) then |
| Next_Elmt (Elmt); |
| end if; |
| |
| Next_Discriminant (Disc_T); |
| end loop; |
| end; |
| |
| elsif Is_Array_Type (Operand_Type) then |
| N_Ix := First_Index (Target_Type); |
| Cons := New_List; |
| |
| for J in 1 .. Number_Dimensions (Operand_Type) loop |
| |
| -- We convert the bounds explicitly. We use an unchecked |
| -- conversion because bounds checks are done elsewhere. |
| |
| Append_To (Cons, |
| Make_Range (Loc, |
| Low_Bound => |
| Unchecked_Convert_To (Etype (N_Ix), |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Duplicate_Subexpr_No_Checks |
| (Operand, Name_Req => True), |
| Attribute_Name => Name_First, |
| Expressions => New_List ( |
| Make_Integer_Literal (Loc, J)))), |
| |
| High_Bound => |
| Unchecked_Convert_To (Etype (N_Ix), |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Duplicate_Subexpr_No_Checks |
| (Operand, Name_Req => True), |
| Attribute_Name => Name_Last, |
| Expressions => New_List ( |
| Make_Integer_Literal (Loc, J)))))); |
| |
| Next_Index (N_Ix); |
| end loop; |
| end if; |
| end if; |
| |
| Odef := New_Occurrence_Of (Target_Type, Loc); |
| |
| if Present (Cons) then |
| Odef := |
| Make_Subtype_Indication (Loc, |
| Subtype_Mark => Odef, |
| Constraint => |
| Make_Index_Or_Discriminant_Constraint (Loc, |
| Constraints => Cons)); |
| end if; |
| |
| Temp := Make_Temporary (Loc, 'C'); |
| Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Object_Definition => Odef); |
| |
| Set_No_Initialization (Decl, True); |
| |
| -- Insert required actions. It is essential to suppress checks |
| -- since we have suppressed default initialization, which means |
| -- that the variable we create may have no discriminants. |
| |
| Insert_Actions (N, |
| New_List ( |
| Decl, |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Temp, Loc), |
| Expression => Relocate_Node (N))), |
| Suppress => All_Checks); |
| |
| Rewrite (N, New_Occurrence_Of (Temp, Loc)); |
| return; |
| end if; |
| end Handle_Changed_Representation; |
| |
| ------------------------------- |
| -- Raise_Accessibility_Error -- |
| ------------------------------- |
| |
| procedure Raise_Accessibility_Error is |
| begin |
| Error_Msg_Warn := SPARK_Mode /= On; |
| Rewrite (N, |
| Make_Raise_Program_Error (Sloc (N), |
| Reason => PE_Accessibility_Check_Failed)); |
| Set_Etype (N, Target_Type); |
| |
| Error_Msg_N ("accessibility check failure<<", N); |
| Error_Msg_N ("\Program_Error [<<", N); |
| end Raise_Accessibility_Error; |
| |
| ---------------------- |
| -- Real_Range_Check -- |
| ---------------------- |
| |
| -- Case of conversions to floating-point or fixed-point. If range checks |
| -- are enabled and the target type has a range constraint, we convert: |
| |
| -- typ (x) |
| |
| -- to |
| |
| -- Tnn : typ'Base := typ'Base (x); |
| -- [constraint_error when Tnn < typ'First or else Tnn > typ'Last] |
| -- typ (Tnn) |
| |
| -- This is necessary when there is a conversion of integer to float or |
| -- to fixed-point to ensure that the correct checks are made. It is not |
| -- necessary for the float-to-float case where it is enough to just set |
| -- the Do_Range_Check flag on the expression. |
| |
| procedure Real_Range_Check is |
| Btyp : constant Entity_Id := Base_Type (Target_Type); |
| Lo : constant Node_Id := Type_Low_Bound (Target_Type); |
| Hi : constant Node_Id := Type_High_Bound (Target_Type); |
| |
| Conv : Node_Id; |
| Hi_Arg : Node_Id; |
| Hi_Val : Node_Id; |
| Lo_Arg : Node_Id; |
| Lo_Val : Node_Id; |
| Expr : Entity_Id; |
| Tnn : Entity_Id; |
| |
| begin |
| -- Nothing more to do if conversion was rewritten |
| |
| if Nkind (N) /= N_Type_Conversion then |
| return; |
| end if; |
| |
| Expr := Expression (N); |
| |
| -- Clear the Do_Range_Check flag on Expr |
| |
| Set_Do_Range_Check (Expr, False); |
| |
| -- Nothing to do if range checks suppressed, or target has the same |
| -- range as the base type (or is the base type). |
| |
| if Range_Checks_Suppressed (Target_Type) |
| or else (Lo = Type_Low_Bound (Btyp) |
| and then |
| Hi = Type_High_Bound (Btyp)) |
| then |
| return; |
| end if; |
| |
| -- Nothing to do if expression is an entity on which checks have been |
| -- suppressed. |
| |
| if Is_Entity_Name (Expr) |
| and then Range_Checks_Suppressed (Entity (Expr)) |
| then |
| return; |
| end if; |
| |
| -- Nothing to do if expression was rewritten into a float-to-float |
| -- conversion, since this kind of conversion is handled elsewhere. |
| |
| if Is_Floating_Point_Type (Etype (Expr)) |
| and then Is_Floating_Point_Type (Target_Type) |
| then |
| return; |
| end if; |
| |
| -- Nothing to do if bounds are all static and we can tell that the |
| -- expression is within the bounds of the target. Note that if the |
| -- operand is of an unconstrained floating-point type, then we do |
| -- not trust it to be in range (might be infinite) |
| |
| declare |
| S_Lo : constant Node_Id := Type_Low_Bound (Etype (Expr)); |
| S_Hi : constant Node_Id := Type_High_Bound (Etype (Expr)); |
| |
| begin |
| if (not Is_Floating_Point_Type (Etype (Expr)) |
| or else Is_Constrained (Etype (Expr))) |
| and then Compile_Time_Known_Value (S_Lo) |
| and then Compile_Time_Known_Value (S_Hi) |
| and then Compile_Time_Known_Value (Hi) |
| and then Compile_Time_Known_Value (Lo) |
| then |
| declare |
| D_Lov : constant Ureal := Expr_Value_R (Lo); |
| D_Hiv : constant Ureal := Expr_Value_R (Hi); |
| S_Lov : Ureal; |
| S_Hiv : Ureal; |
| |
| begin |
| if Is_Real_Type (Etype (Expr)) then |
| S_Lov := Expr_Value_R (S_Lo); |
| S_Hiv := Expr_Value_R (S_Hi); |
| else |
| S_Lov := UR_From_Uint (Expr_Value (S_Lo)); |
| S_Hiv := UR_From_Uint (Expr_Value (S_Hi)); |
| end if; |
| |
| if D_Hiv > D_Lov |
| and then S_Lov >= D_Lov |
| and then S_Hiv <= D_Hiv |
| then |
| return; |
| end if; |
| end; |
| end if; |
| end; |
| |
| -- Otherwise rewrite the conversion as described above |
| |
| Conv := Convert_To (Btyp, Expr); |
| |
| -- If a conversion is necessary, then copy the specific flags from |
| -- the original one and also move the Do_Overflow_Check flag since |
| -- this new conversion is to the base type. |
| |
| if Nkind (Conv) = N_Type_Conversion then |
| Set_Conversion_OK (Conv, Conversion_OK (N)); |
| Set_Float_Truncate (Conv, Float_Truncate (N)); |
| Set_Rounded_Result (Conv, Rounded_Result (N)); |
| |
| if Do_Overflow_Check (N) then |
| Set_Do_Overflow_Check (Conv); |
| Set_Do_Overflow_Check (N, False); |
| end if; |
| end if; |
| |
| Tnn := Make_Temporary (Loc, 'T', Conv); |
| |
| -- For a conversion from Float to Fixed where the bounds of the |
| -- fixed-point type are static, we can obtain a more accurate |
| -- fixed-point value by converting the result of the floating- |
| -- point expression to an appropriate integer type, and then |
| -- performing an unchecked conversion to the target fixed-point |
| -- type. The range check can then use the corresponding integer |
| -- value of the bounds instead of requiring further conversions. |
| -- This preserves the identity: |
| |
| -- Fix_Val = Fixed_Type (Float_Type (Fix_Val)) |
| |
| -- which used to fail when Fix_Val was a bound of the type and |
| -- the 'Small was not a representable number. |
| -- This transformation requires an integer type large enough to |
| -- accommodate a fixed-point value. |
| |
| if Is_Ordinary_Fixed_Point_Type (Target_Type) |
| and then Is_Floating_Point_Type (Etype (Expr)) |
| and then RM_Size (Btyp) <= System_Max_Integer_Size |
| and then Nkind (Lo) = N_Real_Literal |
| and then Nkind (Hi) = N_Real_Literal |
| then |
| declare |
| Expr_Id : constant Entity_Id := Make_Temporary (Loc, 'T', Conv); |
| Int_Typ : constant Entity_Id := |
| Small_Integer_Type_For (RM_Size (Btyp), False); |
| |
| begin |
| -- Generate a temporary with the integer value. Required in the |
| -- CCG compiler to ensure that run-time checks reference this |
| -- integer expression (instead of the resulting fixed-point |
| -- value because fixed-point values are handled by means of |
| -- unsigned integer types). |
| |
| Insert_Action (N, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Expr_Id, |
| Object_Definition => New_Occurrence_Of (Int_Typ, Loc), |
| Constant_Present => True, |
| Expression => |
| Convert_To (Int_Typ, Expression (Conv)))); |
| |
| -- Create integer objects for range checking of result. |
| |
| Lo_Arg := |
| Unchecked_Convert_To |
| (Int_Typ, New_Occurrence_Of (Expr_Id, Loc)); |
| |
| Lo_Val := |
| Make_Integer_Literal (Loc, Corresponding_Integer_Value (Lo)); |
| |
| Hi_Arg := |
| Unchecked_Convert_To |
| (Int_Typ, New_Occurrence_Of (Expr_Id, Loc)); |
| |
| Hi_Val := |
| Make_Integer_Literal (Loc, Corresponding_Integer_Value (Hi)); |
| |
| -- Rewrite conversion as an integer conversion of the |
| -- original floating-point expression, followed by an |
| -- unchecked conversion to the target fixed-point type. |
| |
| Conv := |
| Unchecked_Convert_To |
| (Target_Type, New_Occurrence_Of (Expr_Id, Loc)); |
| end; |
| |
| -- All other conversions |
| |
| else |
| Lo_Arg := New_Occurrence_Of (Tnn, Loc); |
| Lo_Val := |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Target_Type, Loc), |
| Attribute_Name => Name_First); |
| |
| Hi_Arg := New_Occurrence_Of (Tnn, Loc); |
| Hi_Val := |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Target_Type, Loc), |
| Attribute_Name => Name_Last); |
| end if; |
| |
| -- Build code for range checking. Note that checks are suppressed |
| -- here since we don't want a recursive range check popping up. |
| |
| Insert_Actions (N, New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Tnn, |
| Object_Definition => New_Occurrence_Of (Btyp, Loc), |
| Constant_Present => True, |
| Expression => Conv), |
| |
| Make_Raise_Constraint_Error (Loc, |
| Condition => |
| Make_Or_Else (Loc, |
| Left_Opnd => |
| Make_Op_Lt (Loc, |
| Left_Opnd => Lo_Arg, |
| Right_Opnd => Lo_Val), |
| |
| Right_Opnd => |
| Make_Op_Gt (Loc, |
| Left_Opnd => Hi_Arg, |
| Right_Opnd => Hi_Val)), |
| Reason => CE_Range_Check_Failed)), |
| Suppress => All_Checks); |
| |
| Rewrite (Expr, New_Occurrence_Of (Tnn, Loc)); |
| end Real_Range_Check; |
| |
| ----------------------------- |
| -- Has_Extra_Accessibility -- |
| ----------------------------- |
| |
| -- Returns true for a formal of an anonymous access type or for an Ada |
| -- 2012-style stand-alone object of an anonymous access type. |
| |
| function Has_Extra_Accessibility (Id : Entity_Id) return Boolean is |
| begin |
| if Is_Formal (Id) or else Ekind (Id) in E_Constant | E_Variable then |
| return Present (Effective_Extra_Accessibility (Id)); |
| else |
| return False; |
| end if; |
| end Has_Extra_Accessibility; |
| |
| ---------------------------------------- |
| -- Statically_Deeper_Relation_Applies -- |
| ---------------------------------------- |
| |
| function Statically_Deeper_Relation_Applies (Targ_Typ : Entity_Id) |
| return Boolean |
| is |
| begin |
| -- The case where the target type is an anonymous access type is |
| -- ignored since they have different semantics and get covered by |
| -- various runtime checks depending on context. |
| |
| -- Note, the current implementation of this predicate is incomplete |
| -- and doesn't fully reflect the rules given in RM 3.10.2 (19) and |
| -- (19.1) ??? |
| |
| return Ekind (Targ_Typ) /= E_Anonymous_Access_Type; |
| end Statically_Deeper_Relation_Applies; |
| |
| -- Start of processing for Expand_N_Type_Conversion |
| |
| begin |
| -- First remove check marks put by the semantic analysis on the type |
| -- conversion between array types. We need these checks, and they will |
| -- be generated by this expansion routine, but we do not depend on these |
| -- flags being set, and since we do intend to expand the checks in the |
| -- front end, we don't want them on the tree passed to the back end. |
| |
| if Is_Array_Type (Target_Type) then |
| if Is_Constrained (Target_Type) then |
| Set_Do_Length_Check (N, False); |
| else |
| Set_Do_Range_Check (Operand, False); |
| end if; |
| end if; |
| |
| -- Nothing at all to do if conversion is to the identical type so remove |
| -- the conversion completely, it is useless, except that it may carry |
| -- an Assignment_OK attribute, which must be propagated to the operand |
| -- and the Do_Range_Check flag on the operand must be cleared, if any. |
| |
| if Operand_Type = Target_Type then |
| if Assignment_OK (N) then |
| Set_Assignment_OK (Operand); |
| end if; |
| |
| Set_Do_Range_Check (Operand, False); |
| |
| Rewrite (N, Relocate_Node (Operand)); |
| |
| goto Done; |
| end if; |
| |
| -- Nothing to do if this is the second argument of read. This is a |
| -- "backwards" conversion that will be handled by the specialized code |
| -- in attribute processing. |
| |
| if Nkind (Parent (N)) = N_Attribute_Reference |
| and then Attribute_Name (Parent (N)) = Name_Read |
| and then Next (First (Expressions (Parent (N)))) = N |
| then |
| goto Done; |
| end if; |
| |
| -- Check for case of converting to a type that has an invariant |
| -- associated with it. This requires an invariant check. We insert |
| -- a call: |
| |
| -- invariant_check (typ (expr)) |
| |
| -- in the code, after removing side effects from the expression. |
| -- This is clearer than replacing the conversion into an expression |
| -- with actions, because the context may impose additional actions |
| -- (tag checks, membership tests, etc.) that conflict with this |
| -- rewriting (used previously). |
| |
| -- Note: the Comes_From_Source check, and then the resetting of this |
| -- flag prevents what would otherwise be an infinite recursion. |
| |
| if Has_Invariants (Target_Type) |
| and then Present (Invariant_Procedure (Target_Type)) |
| and then Comes_From_Source (N) |
| then |
| Set_Comes_From_Source (N, False); |
| Remove_Side_Effects (N); |
| Insert_Action (N, Make_Invariant_Call (Duplicate_Subexpr (N))); |
| goto Done; |
| |
| -- AI12-0042: For a view conversion to a class-wide type occurring |
| -- within the immediate scope of T, from a specific type that is |
| -- a descendant of T (including T itself), an invariant check is |
| -- performed on the part of the object that is of type T. (We don't |
| -- need to explicitly check for the operand type being a descendant, |
| -- just that it's a specific type, because the conversion would be |
| -- illegal if it's specific and not a descendant -- downward conversion |
| -- is not allowed). |
| |
| elsif Is_Class_Wide_Type (Target_Type) |
| and then not Is_Class_Wide_Type (Etype (Expression (N))) |
| and then Present (Invariant_Procedure (Root_Type (Target_Type))) |
| and then Comes_From_Source (N) |
| and then Within_Scope (Find_Enclosing_Scope (N), Scope (Target_Type)) |
| then |
| Remove_Side_Effects (N); |
| |
| -- Perform the invariant check on a conversion to the class-wide |
| -- type's root type. |
| |
| declare |
| Root_Conv : constant Node_Id := |
| Make_Type_Conversion (Loc, |
| Subtype_Mark => |
| New_Occurrence_Of (Root_Type (Target_Type), Loc), |
| Expression => Duplicate_Subexpr (Expression (N))); |
| begin |
| Set_Etype (Root_Conv, Root_Type (Target_Type)); |
| |
| Insert_Action (N, Make_Invariant_Call (Root_Conv)); |
| goto Done; |
| end; |
| end if; |
| |
| -- Here if we may need to expand conversion |
| |
| -- If the operand of the type conversion is an arithmetic operation on |
| -- signed integers, and the based type of the signed integer type in |
| -- question is smaller than Standard.Integer, we promote both of the |
| -- operands to type Integer. |
| |
| -- For example, if we have |
| |
| -- target-type (opnd1 + opnd2) |
| |
| -- and opnd1 and opnd2 are of type short integer, then we rewrite |
| -- this as: |
| |
| -- target-type (integer(opnd1) + integer(opnd2)) |
| |
| -- We do this because we are always allowed to compute in a larger type |
| -- if we do the right thing with the result, and in this case we are |
| -- going to do a conversion which will do an appropriate check to make |
| -- sure that things are in range of the target type in any case. This |
| -- avoids some unnecessary intermediate overflows. |
| |
| -- We might consider a similar transformation in the case where the |
| -- target is a real type or a 64-bit integer type, and the operand |
| -- is an arithmetic operation using a 32-bit integer type. However, |
| -- we do not bother with this case, because it could cause significant |
| -- inefficiencies on 32-bit machines. On a 64-bit machine it would be |
| -- much cheaper, but we don't want different behavior on 32-bit and |
| -- 64-bit machines. Note that the exclusion of the 64-bit case also |
| -- handles the configurable run-time cases where 64-bit arithmetic |
| -- may simply be unavailable. |
| |
| -- Note: this circuit is partially redundant with respect to the circuit |
| -- in Checks.Apply_Arithmetic_Overflow_Check, but we catch more cases in |
| -- the processing here. Also we still need the Checks circuit, since we |
| -- have to be sure not to generate junk overflow checks in the first |
| -- place, since it would be tricky to remove them here. |
| |
| if Integer_Promotion_Possible (N) then |
| |
| -- All conditions met, go ahead with transformation |
| |
| declare |
| Opnd : Node_Id; |
| L, R : Node_Id; |
| |
| begin |
| Opnd := New_Op_Node (Nkind (Operand), Loc); |
| |
| R := Convert_To (Standard_Integer, Right_Opnd (Operand)); |
| Set_Right_Opnd (Opnd, R); |
| |
| if Nkind (Operand) in N_Binary_Op then |
| L := Convert_To (Standard_Integer, Left_Opnd (Operand)); |
| Set_Left_Opnd (Opnd, L); |
| end if; |
| |
| Rewrite (N, |
| Make_Type_Conversion (Loc, |
| Subtype_Mark => Relocate_Node (Subtype_Mark (N)), |
| Expression => Opnd)); |
| |
| Analyze_And_Resolve (N, Target_Type); |
| goto Done; |
| end; |
| end if; |
| |
| -- If the conversion is from Universal_Integer and requires an overflow |
| -- check, try to do an intermediate conversion to a narrower type first |
| -- without overflow check, in order to avoid doing the overflow check |
| -- in Universal_Integer, which can be a very large type. |
| |
| if Operand_Type = Universal_Integer and then Do_Overflow_Check (N) then |
| declare |
| Lo, Hi, Siz : Uint; |
| OK : Boolean; |
| Typ : Entity_Id; |
| |
| begin |
| Determine_Range (Operand, OK, Lo, Hi, Assume_Valid => True); |
| |
| if OK then |
| Siz := Get_Size_For_Range (Lo, Hi); |
| |
| -- We use the base type instead of the first subtype because |
| -- overflow checks are done in the base type, so this avoids |
| -- the need for useless conversions. |
| |
| if Siz < System_Max_Integer_Size then |
| Typ := Etype (Integer_Type_For (Siz, Uns => False)); |
| |
| Convert_To_And_Rewrite (Typ, Operand); |
| Analyze_And_Resolve |
| (Operand, Typ, Suppress => Overflow_Check); |
| |
| Analyze_And_Resolve (N, Target_Type); |
| goto Done; |
| end if; |
| end if; |
| end; |
| end if; |
| |
| -- Do validity check if validity checking operands |
| |
| if Validity_Checks_On and Validity_Check_Operands then |
| Ensure_Valid (Operand); |
| end if; |
| |
| -- Special case of converting from non-standard boolean type |
| |
| if Is_Boolean_Type (Operand_Type) |
| and then (Nonzero_Is_True (Operand_Type)) |
| then |
| Adjust_Condition (Operand); |
| Set_Etype (Operand, Standard_Boolean); |
| Operand_Type := Standard_Boolean; |
| end if; |
| |
| -- Case of converting to an access type |
| |
| if Is_Access_Type (Target_Type) then |
| -- In terms of accessibility rules, an anonymous access discriminant |
| -- is not considered separate from its parent object. |
| |
| if Nkind (Operand) = N_Selected_Component |
| and then Ekind (Entity (Selector_Name (Operand))) = E_Discriminant |
| and then Ekind (Operand_Type) = E_Anonymous_Access_Type |
| then |
| Operand_Acc := Original_Node (Prefix (Operand)); |
| end if; |
| |
| -- If this type conversion was internally generated by the front end |
| -- to displace the pointer to the object to reference an interface |
| -- type and the original node was an Unrestricted_Access attribute, |
| -- then skip applying accessibility checks (because, according to the |
| -- GNAT Reference Manual, this attribute is similar to 'Access except |
| -- that all accessibility and aliased view checks are omitted). |
| |
| if not Comes_From_Source (N) |
| and then Is_Interface (Designated_Type (Target_Type)) |
| and then Nkind (Original_Node (N)) = N_Attribute_Reference |
| and then Attribute_Name (Original_Node (N)) = |
| Name_Unrestricted_Access |
| then |
| null; |
| |
| -- Apply an accessibility check when the conversion operand is an |
| -- access parameter (or a renaming thereof), unless conversion was |
| -- expanded from an Unchecked_ or Unrestricted_Access attribute, |
| -- or for the actual of a class-wide interface parameter. Note that |
| -- other checks may still need to be applied below (such as tagged |
| -- type checks). |
| |
| elsif Is_Entity_Name (Operand_Acc) |
| and then Has_Extra_Accessibility (Entity (Operand_Acc)) |
| and then Ekind (Etype (Operand_Acc)) = E_Anonymous_Access_Type |
| and then (Nkind (Original_Node (N)) /= N_Attribute_Reference |
| or else Attribute_Name (Original_Node (N)) = Name_Access) |
| and then not No_Dynamic_Accessibility_Checks_Enabled (N) |
| then |
| if not Comes_From_Source (N) |
| and then Nkind (Parent (N)) in N_Function_Call |
| | N_Parameter_Association |
| | N_Procedure_Call_Statement |
| and then Is_Interface (Designated_Type (Target_Type)) |
| and then Is_Class_Wide_Type (Designated_Type (Target_Type)) |
| then |
| null; |
| |
| else |
| Apply_Accessibility_Check |
| (Operand, Target_Type, Insert_Node => Operand); |
| end if; |
| |
| -- If the level of the operand type is statically deeper than the |
| -- level of the target type, then force Program_Error. Note that this |
| -- can only occur for cases where the attribute is within the body of |
| -- an instantiation, otherwise the conversion will already have been |
| -- rejected as illegal. |
| |
| -- Note: warnings are issued by the analyzer for the instance cases, |
| -- and, since we are late in expansion, a check is performed to |
| -- verify that neither the target type nor the operand type are |
| -- internally generated - as this can lead to spurious errors when, |
| -- for example, the operand type is a result of BIP expansion. |
| |
| elsif In_Instance_Body |
| and then Statically_Deeper_Relation_Applies (Target_Type) |
| and then not Is_Internal (Target_Type) |
| and then not Is_Internal (Operand_Type) |
| and then |
| Type_Access_Level (Operand_Type) > Type_Access_Level (Target_Type) |
| then |
| Raise_Accessibility_Error; |
| goto Done; |
| |
| -- When the operand is a selected access discriminant the check needs |
| -- to be made against the level of the object denoted by the prefix |
| -- of the selected name. Force Program_Error for this case as well |
| -- (this accessibility violation can only happen if within the body |
| -- of an instantiation). |
| |
| elsif In_Instance_Body |
| and then Ekind (Operand_Type) = E_Anonymous_Access_Type |
| and then Nkind (Operand) = N_Selected_Component |
| and then Ekind (Entity (Selector_Name (Operand))) = E_Discriminant |
| and then Static_Accessibility_Level (Operand, Zero_On_Dynamic_Level) |
| > Type_Access_Level (Target_Type) |
| then |
| Raise_Accessibility_Error; |
| goto Done; |
| end if; |
| end if; |
| |
| -- Case of conversions of tagged types and access to tagged types |
| |
| -- When needed, that is to say when the expression is class-wide, Add |
| -- runtime a tag check for (strict) downward conversion by using the |
| -- membership test, generating: |
| |
| -- [constraint_error when Operand not in Target_Type'Class] |
| |
| -- or in the access type case |
| |
| -- [constraint_error |
| -- when Operand /= null |
| -- and then Operand.all not in |
| -- Designated_Type (Target_Type)'Class] |
| |
| if (Is_Access_Type (Target_Type) |
| and then Is_Tagged_Type (Designated_Type (Target_Type))) |
| or else Is_Tagged_Type (Target_Type) |
| then |
| -- Do not do any expansion in the access type case if the parent is a |
| -- renaming, since this is an error situation which will be caught by |
| -- Sem_Ch8, and the expansion can interfere with this error check. |
| |
| if Is_Access_Type (Target_Type) and then Is_Renamed_Object (N) then |
| goto Done; |
| end if; |
| |
| -- Otherwise, proceed with processing tagged conversion |
| |
| Tagged_Conversion : declare |
| Actual_Op_Typ : Entity_Id; |
| Actual_Targ_Typ : Entity_Id; |
| Root_Op_Typ : Entity_Id; |
| |
| procedure Make_Tag_Check (Targ_Typ : Entity_Id); |
| -- Create a membership check to test whether Operand is a member |
| -- of Targ_Typ. If the original Target_Type is an access, include |
| -- a test for null value. The check is inserted at N. |
| |
| -------------------- |
| -- Make_Tag_Check -- |
| -------------------- |
| |
| procedure Make_Tag_Check (Targ_Typ : Entity_Id) is |
| Cond : Node_Id; |
| |
| begin |
| -- Generate: |
| -- [Constraint_Error |
| -- when Operand /= null |
| -- and then Operand.all not in Targ_Typ] |
| |
| if Is_Access_Type (Target_Type) then |
| Cond := |
| Make_And_Then (Loc, |
| Left_Opnd => |
| Make_Op_Ne (Loc, |
| Left_Opnd => Duplicate_Subexpr_No_Checks (Operand), |
| Right_Opnd => Make_Null (Loc)), |
| |
| Right_Opnd => |
| Make_Not_In (Loc, |
| Left_Opnd => |
| Make_Explicit_Dereference (Loc, |
| Prefix => Duplicate_Subexpr_No_Checks (Operand)), |
| Right_Opnd => New_Occurrence_Of (Targ_Typ, Loc))); |
| |
| -- Generate: |
| -- [Constraint_Error when Operand not in Targ_Typ] |
| |
| else |
| Cond := |
| Make_Not_In (Loc, |
| Left_Opnd => Duplicate_Subexpr_No_Checks (Operand), |
| Right_Opnd => New_Occurrence_Of (Targ_Typ, Loc)); |
| end if; |
| |
| Insert_Action (N, |
| Make_Raise_Constraint_Error (Loc, |
| Condition => Cond, |
| Reason => CE_Tag_Check_Failed), |
| Suppress => All_Checks); |
| end Make_Tag_Check; |
| |
| -- Start of processing for Tagged_Conversion |
| |
| begin |
| -- Handle entities from the limited view |
| |
| if Is_Access_Type (Operand_Type) then |
| Actual_Op_Typ := |
| Available_View (Designated_Type (Operand_Type)); |
| else |
| Actual_Op_Typ := Operand_Type; |
| end if; |
| |
| if Is_Access_Type (Target_Type) then |
| Actual_Targ_Typ := |
| Available_View (Designated_Type (Target_Type)); |
| else |
| Actual_Targ_Typ := Target_Type; |
| end if; |
| |
| Root_Op_Typ := Root_Type (Actual_Op_Typ); |
| |
| -- Ada 2005 (AI-251): Handle interface type conversion |
| |
| if Is_Interface (Actual_Op_Typ) |
| or else |
| Is_Interface (Actual_Targ_Typ) |
| then |
| Expand_Interface_Conversion (N); |
| goto Done; |
| end if; |
| |
| -- Create a runtime tag check for a downward CW type conversion |
| |
| if Is_Class_Wide_Type (Actual_Op_Typ) |
| and then Actual_Op_Typ /= Actual_Targ_Typ |
| and then Root_Op_Typ /= Actual_Targ_Typ |
| and then Is_Ancestor |
| (Root_Op_Typ, Actual_Targ_Typ, Use_Full_View => True) |
| and then not Tag_Checks_Suppressed (Actual_Targ_Typ) |
| then |
| declare |
| Conv : Node_Id; |
| begin |
| Make_Tag_Check (Class_Wide_Type (Actual_Targ_Typ)); |
| Conv := Unchecked_Convert_To (Target_Type, Expression (N)); |
| Rewrite (N, Conv); |
| Analyze_And_Resolve (N, Target_Type); |
| end; |
| end if; |
| end Tagged_Conversion; |
| |
| -- Case of other access type conversions |
| |
| elsif Is_Access_Type (Target_Type) then |
| Apply_Constraint_Check (Operand, Target_Type); |
| |
| -- Case of conversions from a fixed-point type |
| |
| -- These conversions require special expansion and processing, found in |
| -- the Exp_Fixd package. We ignore cases where Conversion_OK is set, |
| -- since from a semantic point of view, these are simple integer |
| -- conversions, which do not need further processing except for the |
| -- generation of range checks, which is performed at the end of this |
| -- procedure. |
| |
| elsif Is_Fixed_Point_Type (Operand_Type) |
| and then not Conversion_OK (N) |
| then |
| -- We should never see universal fixed at this case, since the |
| -- expansion of the constituent divide or multiply should have |
| -- eliminated the explicit mention of universal fixed. |
| |
| pragma Assert (Operand_Type /= Universal_Fixed); |
| |
| -- Check for special case of the conversion to universal real that |
| -- occurs as a result of the use of a round attribute. In this case, |
| -- the real type for the conversion is taken from the target type of |
| -- the Round attribute and the result must be marked as rounded. |
| |
| if Target_Type = Universal_Real |
| and then Nkind (Parent (N)) = N_Attribute_Reference |
| and then Attribute_Name (Parent (N)) = Name_Round |
| then |
| Set_Etype (N, Etype (Parent (N))); |
| Target_Type := Etype (N); |
| Set_Rounded_Result (N); |
| end if; |
| |
| if Is_Fixed_Point_Type (Target_Type) then |
| Expand_Convert_Fixed_To_Fixed (N); |
| elsif Is_Integer_Type (Target_Type) then |
| Expand_Convert_Fixed_To_Integer (N); |
| else |
| pragma Assert (Is_Floating_Point_Type (Target_Type)); |
| Expand_Convert_Fixed_To_Float (N); |
| end if; |
| |
| -- Case of conversions to a fixed-point type |
| |
| -- These conversions require special expansion and processing, found in |
| -- the Exp_Fixd package. Again, ignore cases where Conversion_OK is set, |
| -- since from a semantic point of view, these are simple integer |
| -- conversions, which do not need further processing. |
| |
| elsif Is_Fixed_Point_Type (Target_Type) |
| and then not Conversion_OK (N) |
| then |
| if Is_Integer_Type (Operand_Type) then |
| Expand_Convert_Integer_To_Fixed (N); |
| else |
| pragma Assert (Is_Floating_Point_Type (Operand_Type)); |
| Expand_Convert_Float_To_Fixed (N); |
| end if; |
| |
| -- Case of array conversions |
| |
| -- Expansion of array conversions, add required length/range checks but |
| -- only do this if there is no change of representation. For handling of |
| -- this case, see Handle_Changed_Representation. |
| |
| elsif Is_Array_Type (Target_Type) then |
| if Is_Constrained (Target_Type) then |
| Apply_Length_Check (Operand, Target_Type); |
| else |
| -- If the object has an unconstrained array subtype with fixed |
| -- lower bound, then sliding to that bound may be needed. |
| |
| if Is_Fixed_Lower_Bound_Array_Subtype (Target_Type) then |
| Expand_Sliding_Conversion (Operand, Target_Type); |
| end if; |
| |
| Apply_Range_Check (Operand, Target_Type); |
| end if; |
| |
| Handle_Changed_Representation; |
| |
| -- Case of conversions of discriminated types |
| |
| -- Add required discriminant checks if target is constrained. Again this |
| -- change is skipped if we have a change of representation. |
| |
| elsif Has_Discriminants (Target_Type) |
| and then Is_Constrained (Target_Type) |
| then |
| Apply_Discriminant_Check (Operand, Target_Type); |
| Handle_Changed_Representation; |
| |
| -- Case of all other record conversions. The only processing required |
| -- is to check for a change of representation requiring the special |
| -- assignment processing. |
| |
| elsif Is_Record_Type (Target_Type) then |
| |
| -- Ada 2005 (AI-216): Program_Error is raised when converting from |
| -- a derived Unchecked_Union type to an unconstrained type that is |
| -- not Unchecked_Union if the operand lacks inferable discriminants. |
| |
| if Is_Derived_Type (Operand_Type) |
| and then Is_Unchecked_Union (Base_Type (Operand_Type)) |
| and then not Is_Constrained (Target_Type) |
| and then not Is_Unchecked_Union (Base_Type (Target_Type)) |
| and then not Has_Inferable_Discriminants (Operand) |
| then |
| -- To prevent Gigi from generating illegal code, we generate a |
| -- Program_Error node, but we give it the target type of the |
| -- conversion (is this requirement documented somewhere ???) |
| |
| declare |
| PE : constant Node_Id := Make_Raise_Program_Error (Loc, |
| Reason => PE_Unchecked_Union_Restriction); |
| |
| begin |
| Set_Etype (PE, Target_Type); |
| Rewrite (N, PE); |
| |
| end; |
| else |
| Handle_Changed_Representation; |
| end if; |
| |
| -- Case of conversions of enumeration types |
| |
| elsif Is_Enumeration_Type (Target_Type) then |
| |
| -- Special processing is required if there is a change of |
| -- representation (from enumeration representation clauses). |
| |
| if not Has_Compatible_Representation (Target_Type, Operand_Type) |
| and then not Conversion_OK (N) |
| then |
| if Optimization_Level > 0 |
| and then Is_Boolean_Type (Target_Type) |
| then |
| -- Convert x(y) to (if y then x'(True) else x'(False)). |
| -- Use literals, instead of indexing x'val, to enable |
| -- further optimizations in the middle-end. |
| |
| Rewrite (N, |
| Make_If_Expression (Loc, |
| Expressions => New_List ( |
| Operand, |
| Convert_To (Target_Type, |
| New_Occurrence_Of (Standard_True, Loc)), |
| Convert_To (Target_Type, |
| New_Occurrence_Of (Standard_False, Loc))))); |
| |
| else |
| -- Convert: x(y) to x'val (ytyp'pos (y)) |
| |
| Rewrite (N, |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Target_Type, Loc), |
| Attribute_Name => Name_Val, |
| Expressions => New_List ( |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Operand_Type, Loc), |
| Attribute_Name => Name_Pos, |
| Expressions => New_List (Operand))))); |
| end if; |
| |
| Analyze_And_Resolve (N, Target_Type); |
| end if; |
| end if; |
| |
| -- At this stage, either the conversion node has been transformed into |
| -- some other equivalent expression, or left as a conversion that can be |
| -- handled by Gigi. |
| |
| -- The only remaining step is to generate a range check if we still have |
| -- a type conversion at this stage and Do_Range_Check is set. Note that |
| -- we need to deal with at most 8 out of the 9 possible cases of numeric |
| -- conversions here, because the float-to-integer case is entirely dealt |
| -- with by Apply_Float_Conversion_Check. |
| |
| if Nkind (N) = N_Type_Conversion |
| and then Do_Range_Check (Expression (N)) |
| then |
| -- Float-to-float conversions |
| |
| if Is_Floating_Point_Type (Target_Type) |
| and then Is_Floating_Point_Type (Etype (Expression (N))) |
| then |
| -- Reset overflow flag, since the range check will include |
| -- dealing with possible overflow, and generate the check. |
| |
| Set_Do_Overflow_Check (N, False); |
| |
| Generate_Range_Check |
| (Expression (N), Target_Type, CE_Range_Check_Failed); |
| |
| -- Discrete-to-discrete conversions or fixed-point-to-discrete |
| -- conversions when Conversion_OK is set. |
| |
| elsif Is_Discrete_Type (Target_Type) |
| and then (Is_Discrete_Type (Etype (Expression (N))) |
| or else (Is_Fixed_Point_Type (Etype (Expression (N))) |
| and then Conversion_OK (N))) |
| then |
| -- If Address is either a source type or target type, |
| -- suppress range check to avoid typing anomalies when |
| -- it is a visible integer type. |
| |
| if Is_Descendant_Of_Address (Etype (Expression (N))) |
| or else Is_Descendant_Of_Address (Target_Type) |
| then |
| Set_Do_Range_Check (Expression (N), False); |
| else |
| Discrete_Range_Check; |
| end if; |
| |
| -- Conversions to floating- or fixed-point when Conversion_OK is set |
| |
| elsif Is_Floating_Point_Type (Target_Type) |
| or else (Is_Fixed_Point_Type (Target_Type) |
| and then Conversion_OK (N)) |
| then |
| Real_Range_Check; |
| end if; |
| |
| pragma Assert (not Do_Range_Check (Expression (N))); |
| end if; |
| |
| -- Here at end of processing |
| |
| <<Done>> |
| -- Apply predicate check if required. Note that we can't just call |
| -- Apply_Predicate_Check here, because the type looks right after |
| -- the conversion and it would omit the check. The Comes_From_Source |
| -- guard is necessary to prevent infinite recursions when we generate |
| -- internal conversions for the purpose of checking predicates. |
| |
| -- A view conversion of a tagged object is an object and can appear |
| -- in an assignment context, in which case no predicate check applies |
| -- to the now-dead value. |
| |
| if Nkind (Parent (N)) = N_Assignment_Statement |
| and then N = Name (Parent (N)) |
| then |
| null; |
| |
| elsif Predicate_Enabled (Target_Type) |
| and then Target_Type /= Operand_Type |
| and then Comes_From_Source (N) |
| then |
| declare |
| New_Expr : constant Node_Id := Duplicate_Subexpr (N); |
| |
| begin |
| -- Avoid infinite recursion on the subsequent expansion of the |
| -- copy of the original type conversion. When needed, a range |
| -- check has already been applied to the expression. |
| |
| Set_Comes_From_Source (New_Expr, False); |
| Insert_Action (N, |
| Make_Predicate_Check (Target_Type, New_Expr), |
| Suppress => Range_Check); |
| end; |
| end if; |
| end Expand_N_Type_Conversion; |
| |
| ----------------------------------- |
| -- Expand_N_Unchecked_Expression -- |
| ----------------------------------- |
| |
| -- Remove the unchecked expression node from the tree. Its job was simply |
| -- to make sure that its constituent expression was handled with checks |
| -- off, and now that is done, we can remove it from the tree, and indeed |
| -- must, since Gigi does not expect to see these nodes. |
| |
| procedure Expand_N_Unchecked_Expression (N : Node_Id) is |
| Exp : constant Node_Id := Expression (N); |
| begin |
| Set_Assignment_OK (Exp, Assignment_OK (N) or else Assignment_OK (Exp)); |
| Rewrite (N, Exp); |
| end Expand_N_Unchecked_Expression; |
| |
| ---------------------------------------- |
| -- Expand_N_Unchecked_Type_Conversion -- |
| ---------------------------------------- |
| |
| -- If this cannot be handled by Gigi and we haven't already made a |
| -- temporary for it, do it now. |
| |
| procedure Expand_N_Unchecked_Type_Conversion (N : Node_Id) is |
| Target_Type : constant Entity_Id := Etype (N); |
| Operand : constant Node_Id := Expression (N); |
| Operand_Type : constant Entity_Id := Etype (Operand); |
| |
| begin |
| -- Nothing at all to do if conversion is to the identical type so remove |
| -- the conversion completely, it is useless, except that it may carry |
| -- an Assignment_OK indication which must be propagated to the operand. |
| |
| if Operand_Type = Target_Type then |
| Expand_N_Unchecked_Expression (N); |
| return; |
| end if; |
| |
| -- Generate an extra temporary for cases unsupported by the C backend |
| |
| if Modify_Tree_For_C then |
| declare |
| Source : constant Node_Id := Unqual_Conv (Expression (N)); |
| Source_Typ : Entity_Id := Get_Full_View (Etype (Source)); |
| |
| begin |
| if Is_Packed_Array (Source_Typ) then |
| Source_Typ := Packed_Array_Impl_Type (Source_Typ); |
| end if; |
| |
| if Nkind (Source) = N_Function_Call |
| and then (Is_Composite_Type (Etype (Source)) |
| or else Is_Composite_Type (Target_Type)) |
| then |
| Force_Evaluation (Source); |
| end if; |
| end; |
| end if; |
| |
| -- Nothing to do if conversion is safe |
| |
| if Safe_Unchecked_Type_Conversion (N) then |
| return; |
| end if; |
| |
| if Assignment_OK (N) then |
| null; |
| else |
| Force_Evaluation (N); |
| end if; |
| end Expand_N_Unchecked_Type_Conversion; |
| |
| ---------------------------- |
| -- Expand_Record_Equality -- |
| ---------------------------- |
| |
| -- For non-variant records, Equality is expanded when needed into: |
| |
| -- and then Lhs.Discr1 = Rhs.Discr1 |
| -- and then ... |
| -- and then Lhs.Discrn = Rhs.Discrn |
| -- and then Lhs.Cmp1 = Rhs.Cmp1 |
| -- and then ... |
| -- and then Lhs.Cmpn = Rhs.Cmpn |
| |
| -- The expression is folded by the back end for adjacent fields. This |
| -- function is called for tagged record in only one occasion: for imple- |
| -- menting predefined primitive equality (see Predefined_Primitives_Bodies) |
| -- otherwise the primitive "=" is used directly. |
| |
| function Expand_Record_Equality |
| (Nod : Node_Id; |
| Typ : Entity_Id; |
| Lhs : Node_Id; |
| Rhs : Node_Id) return Node_Id |
| is |
| Loc : constant Source_Ptr := Sloc (Nod); |
| |
| Result : Node_Id; |
| C : Entity_Id; |
| |
| First_Time : Boolean := True; |
| |
| function Element_To_Compare (C : Entity_Id) return Entity_Id; |
| -- Return the next discriminant or component to compare, starting with |
| -- C, skipping inherited components. |
| |
| ------------------------ |
| -- Element_To_Compare -- |
| ------------------------ |
| |
| function Element_To_Compare (C : Entity_Id) return Entity_Id is |
| Comp : Entity_Id := C; |
| |
| begin |
| while Present (Comp) loop |
| -- Skip inherited components |
| |
| -- Note: for a tagged type, we always generate the "=" primitive |
| -- for the base type (not on the first subtype), so the test for |
| -- Comp /= Original_Record_Component (Comp) is True for inherited |
| -- components only. |
| |
| if (Is_Tagged_Type (Typ) |
| and then Comp /= Original_Record_Component (Comp)) |
| |
| -- Skip _Tag |
| |
| or else Chars (Comp) = Name_uTag |
| |
| -- Skip interface elements (secondary tags???) |
| |
| or else Is_Interface (Etype (Comp)) |
| then |
| Next_Component_Or_Discriminant (Comp); |
| else |
| return Comp; |
| end if; |
| end loop; |
| |
| return Empty; |
| end Element_To_Compare; |
| |
| -- Start of processing for Expand_Record_Equality |
| |
| begin |
| -- Generates the following code: (assuming that Typ has one Discr and |
| -- component C2 is also a record) |
| |
| -- Lhs.Discr1 = Rhs.Discr1 |
| -- and then Lhs.C1 = Rhs.C1 |
| -- and then Lhs.C2.C1=Rhs.C2.C1 and then ... Lhs.C2.Cn=Rhs.C2.Cn |
| -- and then ... |
| -- and then Lhs.Cmpn = Rhs.Cmpn |
| |
| Result := New_Occurrence_Of (Standard_True, Loc); |
| C := Element_To_Compare (First_Component_Or_Discriminant (Typ)); |
| while Present (C) loop |
| declare |
| New_Lhs : Node_Id; |
| New_Rhs : Node_Id; |
| Check : Node_Id; |
| |
| begin |
| if First_Time then |
| New_Lhs := Lhs; |
| New_Rhs := Rhs; |
| else |
| New_Lhs := New_Copy_Tree (Lhs); |
| New_Rhs := New_Copy_Tree (Rhs); |
| end if; |
| |
| Check := |
| Expand_Composite_Equality (Nod, Etype (C), |
| Lhs => |
| Make_Selected_Component (Loc, |
| Prefix => New_Lhs, |
| Selector_Name => New_Occurrence_Of (C, Loc)), |
| Rhs => |
| Make_Selected_Component (Loc, |
| Prefix => New_Rhs, |
| Selector_Name => New_Occurrence_Of (C, Loc))); |
| |
| -- If some (sub)component is an unchecked_union, the whole |
| -- operation will raise program error. |
| |
| if Nkind (Check) = N_Raise_Program_Error then |
| Result := Check; |
| Set_Etype (Result, Standard_Boolean); |
| exit; |
| else |
| if First_Time then |
| Result := Check; |
| |
| -- Generate logical "and" for CodePeer to simplify the |
| -- generated code and analysis. |
| |
| elsif CodePeer_Mode then |
| Result := |
| Make_Op_And (Loc, |
| Left_Opnd => Result, |
| Right_Opnd => Check); |
| |
| else |
| Result := |
| Make_And_Then (Loc, |
| Left_Opnd => Result, |
| Right_Opnd => Check); |
| end if; |
| end if; |
| end; |
| |
| First_Time := False; |
| C := Element_To_Compare (Next_Component_Or_Discriminant (C)); |
| end loop; |
| |
| return Result; |
| end Expand_Record_Equality; |
| |
| --------------------------- |
| -- Expand_Set_Membership -- |
| --------------------------- |
| |
| procedure Expand_Set_Membership (N : Node_Id) is |
| Lop : constant Node_Id := Left_Opnd (N); |
| Alt : Node_Id; |
| Res : Node_Id; |
| |
| function Make_Cond (Alt : Node_Id) return Node_Id; |
| -- If the alternative is a subtype mark, create a simple membership |
| -- test. Otherwise create an equality test for it. |
| |
| --------------- |
| -- Make_Cond -- |
| --------------- |
| |
| function Make_Cond (Alt : Node_Id) return Node_Id is |
| Cond : Node_Id; |
| L : constant Node_Id := New_Copy_Tree (Lop); |
| R : constant Node_Id := Relocate_Node (Alt); |
| |
| begin |
| if (Is_Entity_Name (Alt) and then Is_Type (Entity (Alt))) |
| or else Nkind (Alt) = N_Range |
| then |
| Cond := Make_In (Sloc (Alt), Left_Opnd => L, Right_Opnd => R); |
| |
| else |
| Cond := Make_Op_Eq (Sloc (Alt), Left_Opnd => L, Right_Opnd => R); |
| Resolve_Membership_Equality (Cond, Etype (Alt)); |
| end if; |
| |
| return Cond; |
| end Make_Cond; |
| |
| -- Start of processing for Expand_Set_Membership |
| |
| begin |
| Remove_Side_Effects (Lop); |
| |
| Alt := First (Alternatives (N)); |
| Res := Make_Cond (Alt); |
| Next (Alt); |
| |
| -- We use left associativity as in the equivalent boolean case. This |
| -- kind of canonicalization helps the optimizer of the code generator. |
| |
| while Present (Alt) loop |
| Res := |
| Make_Or_Else (Sloc (Alt), |
| Left_Opnd => Res, |
| Right_Opnd => Make_Cond (Alt)); |
| Next (Alt); |
| end loop; |
| |
| Rewrite (N, Res); |
| Analyze_And_Resolve (N, Standard_Boolean); |
| end Expand_Set_Membership; |
| |
| ----------------------------------- |
| -- Expand_Short_Circuit_Operator -- |
| ----------------------------------- |
| |
| -- Deal with special expansion if actions are present for the right operand |
| -- and deal with optimizing case of arguments being True or False. We also |
| -- deal with the special case of non-standard boolean values. |
| |
| procedure Expand_Short_Circuit_Operator (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| Left : constant Node_Id := Left_Opnd (N); |
| Right : constant Node_Id := Right_Opnd (N); |
| LocR : constant Source_Ptr := Sloc (Right); |
| Actlist : List_Id; |
| |
| Shortcut_Value : constant Boolean := Nkind (N) = N_Or_Else; |
| Shortcut_Ent : constant Entity_Id := Boolean_Literals (Shortcut_Value); |
| -- If Left = Shortcut_Value then Right need not be evaluated |
| |
| function Make_Test_Expr (Opnd : Node_Id) return Node_Id; |
| -- For Opnd a boolean expression, return a Boolean expression equivalent |
| -- to Opnd /= Shortcut_Value. |
| |
| function Useful (Actions : List_Id) return Boolean; |
| -- Return True if Actions is not empty and contains useful nodes to |
| -- process. |
| |
| -------------------- |
| -- Make_Test_Expr -- |
| -------------------- |
| |
| function Make_Test_Expr (Opnd : Node_Id) return Node_Id is |
| begin |
| if Shortcut_Value then |
| return Make_Op_Not (Sloc (Opnd), Opnd); |
| else |
| return Opnd; |
| end if; |
| end Make_Test_Expr; |
| |
| ------------ |
| -- Useful -- |
| ------------ |
| |
| function Useful (Actions : List_Id) return Boolean is |
| L : Node_Id; |
| begin |
| if Present (Actions) then |
| L := First (Actions); |
| |
| -- For now "useful" means not N_Variable_Reference_Marker. |
| -- Consider stripping other nodes in the future. |
| |
| while Present (L) loop |
| if Nkind (L) /= N_Variable_Reference_Marker then |
| return True; |
| end if; |
| |
| Next (L); |
| end loop; |
| end if; |
| |
| return False; |
| end Useful; |
| |
| -- Local variables |
| |
| Op_Var : Entity_Id; |
| -- Entity for a temporary variable holding the value of the operator, |
| -- used for expansion in the case where actions are present. |
| |
| -- Start of processing for Expand_Short_Circuit_Operator |
| |
| begin |
| -- Deal with non-standard booleans |
| |
| if Is_Boolean_Type (Typ) then |
| Adjust_Condition (Left); |
| Adjust_Condition (Right); |
| Set_Etype (N, Standard_Boolean); |
| end if; |
| |
| -- Check for cases where left argument is known to be True or False |
| |
| if Compile_Time_Known_Value (Left) then |
| |
| -- Mark SCO for left condition as compile time known |
| |
| if Generate_SCO and then Comes_From_Source (Left) then |
| Set_SCO_Condition (Left, Expr_Value_E (Left) = Standard_True); |
| end if; |
| |
| -- Rewrite True AND THEN Right / False OR ELSE Right to Right. |
| -- Any actions associated with Right will be executed unconditionally |
| -- and can thus be inserted into the tree unconditionally. |
| |
| if Expr_Value_E (Left) /= Shortcut_Ent then |
| if Present (Actions (N)) then |
| Insert_Actions (N, Actions (N)); |
| end if; |
| |
| Rewrite (N, Right); |
| |
| -- Rewrite False AND THEN Right / True OR ELSE Right to Left. |
| -- In this case we can forget the actions associated with Right, |
| -- since they will never be executed. |
| |
| else |
| Kill_Dead_Code (Right); |
| Kill_Dead_Code (Actions (N)); |
| Rewrite (N, New_Occurrence_Of (Shortcut_Ent, Loc)); |
| end if; |
| |
| Adjust_Result_Type (N, Typ); |
| return; |
| end if; |
| |
| -- If Actions are present for the right operand, we have to do some |
| -- special processing. We can't just let these actions filter back into |
| -- code preceding the short circuit (which is what would have happened |
| -- if we had not trapped them in the short-circuit form), since they |
| -- must only be executed if the right operand of the short circuit is |
| -- executed and not otherwise. |
| |
| if Useful (Actions (N)) then |
| Actlist := Actions (N); |
| |
| -- The old approach is to expand: |
| |
| -- left AND THEN right |
| |
| -- into |
| |
| -- C : Boolean := False; |
| -- IF left THEN |
| -- Actions; |
| -- IF right THEN |
| -- C := True; |
| -- END IF; |
| -- END IF; |
| |
| -- and finally rewrite the operator into a reference to C. Similarly |
| -- for left OR ELSE right, with negated values. Note that this |
| -- rewrite causes some difficulties for coverage analysis because |
| -- of the introduction of the new variable C, which obscures the |
| -- structure of the test. |
| |
| -- We use this "old approach" if Minimize_Expression_With_Actions |
| -- is True. |
| |
| if Minimize_Expression_With_Actions then |
| Op_Var := Make_Temporary (Loc, 'C', Related_Node => N); |
| |
| Insert_Action (N, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Op_Var, |
| Object_Definition => |
| New_Occurrence_Of (Standard_Boolean, Loc), |
| Expression => |
| New_Occurrence_Of (Shortcut_Ent, Loc))); |
| |
| Append_To (Actlist, |
| Make_Implicit_If_Statement (Right, |
| Condition => Make_Test_Expr (Right), |
| Then_Statements => New_List ( |
| Make_Assignment_Statement (LocR, |
| Name => New_Occurrence_Of (Op_Var, LocR), |
| Expression => |
| New_Occurrence_Of |
| (Boolean_Literals (not Shortcut_Value), LocR))))); |
| |
| Insert_Action (N, |
| Make_Implicit_If_Statement (Left, |
| Condition => Make_Test_Expr (Left), |
| Then_Statements => Actlist)); |
| |
| Rewrite (N, New_Occurrence_Of (Op_Var, Loc)); |
| Analyze_And_Resolve (N, Standard_Boolean); |
| |
| -- The new approach (the default) is to use an |
| -- Expression_With_Actions node for the right operand of the |
| -- short-circuit form. Note that this solves the traceability |
| -- problems for coverage analysis. |
| |
| else |
| Rewrite (Right, |
| Make_Expression_With_Actions (LocR, |
| Expression => Relocate_Node (Right), |
| Actions => Actlist)); |
| |
| Set_Actions (N, No_List); |
| Analyze_And_Resolve (Right, Standard_Boolean); |
| end if; |
| |
| Adjust_Result_Type (N, Typ); |
| return; |
| end if; |
| |
| -- No actions present, check for cases of right argument True/False |
| |
| if Compile_Time_Known_Value (Right) then |
| |
| -- Mark SCO for left condition as compile time known |
| |
| if Generate_SCO and then Comes_From_Source (Right) then |
| Set_SCO_Condition (Right, Expr_Value_E (Right) = Standard_True); |
| end if; |
| |
| -- Change (Left and then True), (Left or else False) to Left. Note |
| -- that we know there are no actions associated with the right |
| -- operand, since we just checked for this case above. |
| |
| if Expr_Value_E (Right) /= Shortcut_Ent then |
| Rewrite (N, Left); |
| |
| -- Change (Left and then False), (Left or else True) to Right, |
| -- making sure to preserve any side effects associated with the Left |
| -- operand. |
| |
| else |
| Remove_Side_Effects (Left); |
| Rewrite (N, New_Occurrence_Of (Shortcut_Ent, Loc)); |
| end if; |
| end if; |
| |
| Adjust_Result_Type (N, Typ); |
| end Expand_Short_Circuit_Operator; |
| |
| ------------------------------------ |
| -- Fixup_Universal_Fixed_Operation -- |
| ------------------------------------- |
| |
| procedure Fixup_Universal_Fixed_Operation (N : Node_Id) is |
| Conv : constant Node_Id := Parent (N); |
| |
| begin |
| -- We must have a type conversion immediately above us |
| |
| pragma Assert (Nkind (Conv) = N_Type_Conversion); |
| |
| -- Normally the type conversion gives our target type. The exception |
| -- occurs in the case of the Round attribute, where the conversion |
| -- will be to universal real, and our real type comes from the Round |
| -- attribute (as well as an indication that we must round the result) |
| |
| if Etype (Conv) = Universal_Real |
| and then Nkind (Parent (Conv)) = N_Attribute_Reference |
| and then Attribute_Name (Parent (Conv)) = Name_Round |
| then |
| Set_Etype (N, Base_Type (Etype (Parent (Conv)))); |
| Set_Rounded_Result (N); |
| |
| -- Normal case where type comes from conversion above us |
| |
| else |
| Set_Etype (N, Base_Type (Etype (Conv))); |
| end if; |
| end Fixup_Universal_Fixed_Operation; |
| |
| ---------------------------- |
| -- Get_First_Index_Bounds -- |
| ---------------------------- |
| |
| procedure Get_First_Index_Bounds (T : Entity_Id; Lo, Hi : out Uint) is |
| Typ : Entity_Id; |
| |
| begin |
| pragma Assert (Is_Array_Type (T)); |
| |
| -- This follows Sem_Eval.Compile_Time_Known_Bounds |
| |
| if Ekind (T) = E_String_Literal_Subtype then |
| Lo := Expr_Value (String_Literal_Low_Bound (T)); |
| Hi := Lo + String_Literal_Length (T) - 1; |
| |
| else |
| Typ := Underlying_Type (Etype (First_Index (T))); |
| |
| Lo := Expr_Value (Type_Low_Bound (Typ)); |
| Hi := Expr_Value (Type_High_Bound (Typ)); |
| end if; |
| end Get_First_Index_Bounds; |
| |
| ------------------------ |
| -- Get_Size_For_Range -- |
| ------------------------ |
| |
| function Get_Size_For_Range (Lo, Hi : Uint) return Uint is |
| |
| function Is_OK_For_Range (Siz : Uint) return Boolean; |
| -- Return True if a signed integer with given size can cover Lo .. Hi |
| |
| -------------------------- |
| -- Is_OK_For_Range -- |
| -------------------------- |
| |
| function Is_OK_For_Range (Siz : Uint) return Boolean is |
| B : constant Uint := Uint_2 ** (Siz - 1); |
| |
| begin |
| -- Test B = 2 ** (size - 1) (can accommodate -B .. +(B - 1)) |
| |
| return Lo >= -B and then Hi >= -B and then Lo < B and then Hi < B; |
| end Is_OK_For_Range; |
| |
| begin |
| -- This is (almost always) the size of Integer |
| |
| if Is_OK_For_Range (Uint_32) then |
| return Uint_32; |
| |
| -- Check 63 |
| |
| elsif Is_OK_For_Range (Uint_63) then |
| return Uint_63; |
| |
| -- This is (almost always) the size of Long_Long_Integer |
| |
| elsif Is_OK_For_Range (Uint_64) then |
| return Uint_64; |
| |
| -- Check 127 |
| |
| elsif Is_OK_For_Range (Uint_127) then |
| return Uint_127; |
| |
| else |
| return Uint_128; |
| end if; |
| end Get_Size_For_Range; |
| |
| ------------------------------- |
| -- Insert_Dereference_Action -- |
| ------------------------------- |
| |
| procedure Insert_Dereference_Action (N : Node_Id) is |
| function Is_Checked_Storage_Pool (P : Entity_Id) return Boolean; |
| -- Return true if type of P is derived from Checked_Pool; |
| |
| ----------------------------- |
| -- Is_Checked_Storage_Pool -- |
| ----------------------------- |
| |
| function Is_Checked_Storage_Pool (P : Entity_Id) return Boolean is |
| T : Entity_Id; |
| |
| begin |
| if No (P) then |
| return False; |
| end if; |
| |
| T := Etype (P); |
| while T /= Etype (T) loop |
| if Is_RTE (T, RE_Checked_Pool) then |
| return True; |
| else |
| T := Etype (T); |
| end if; |
| end loop; |
| |
| return False; |
| end Is_Checked_Storage_Pool; |
| |
| -- Local variables |
| |
| Context : constant Node_Id := Parent (N); |
| Ptr_Typ : constant Entity_Id := Etype (N); |
| Desig_Typ : constant Entity_Id := |
| Available_View (Designated_Type (Ptr_Typ)); |
| Loc : constant Source_Ptr := Sloc (N); |
| Pool : constant Entity_Id := Associated_Storage_Pool (Ptr_Typ); |
| |
| Addr : Entity_Id; |
| Alig : Entity_Id; |
| Deref : Node_Id; |
| Size : Entity_Id; |
| Size_Bits : Node_Id; |
| Stmt : Node_Id; |
| |
| -- Start of processing for Insert_Dereference_Action |
| |
| begin |
| pragma Assert (Nkind (Context) = N_Explicit_Dereference); |
| |
| -- Do not re-expand a dereference which has already been processed by |
| -- this routine. |
| |
| if Has_Dereference_Action (Context) then |
| return; |
| |
| -- Do not perform this type of expansion for internally-generated |
| -- dereferences. |
| |
| elsif not Comes_From_Source (Original_Node (Context)) then |
| return; |
| |
| -- A dereference action is only applicable to objects which have been |
| -- allocated on a checked pool. |
| |
| elsif not Is_Checked_Storage_Pool (Pool) then |
| return; |
| end if; |
| |
| -- Extract the address of the dereferenced object. Generate: |
| |
| -- Addr : System.Address := <N>'Pool_Address; |
| |
| Addr := Make_Temporary (Loc, 'P'); |
| |
| Insert_Action (N, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Addr, |
| Object_Definition => |
| New_Occurrence_Of (RTE (RE_Address), Loc), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => Duplicate_Subexpr_Move_Checks (N), |
| Attribute_Name => Name_Pool_Address))); |
| |
| -- Calculate the size of the dereferenced object. Generate: |
| |
| -- Size : Storage_Count := <N>.all'Size / Storage_Unit; |
| |
| Deref := |
| Make_Explicit_Dereference (Loc, |
| Prefix => Duplicate_Subexpr_Move_Checks (N)); |
| Set_Has_Dereference_Action (Deref); |
| |
| Size_Bits := |
| Make_Attribute_Reference (Loc, |
| Prefix => Deref, |
| Attribute_Name => Name_Size); |
| |
| -- Special case of an unconstrained array: need to add descriptor size |
| |
| if Is_Array_Type (Desig_Typ) |
| and then not Is_Constrained (First_Subtype (Desig_Typ)) |
| then |
| Size_Bits := |
| Make_Op_Add (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of (First_Subtype (Desig_Typ), Loc), |
| Attribute_Name => Name_Descriptor_Size), |
| Right_Opnd => Size_Bits); |
| end if; |
| |
| Size := Make_Temporary (Loc, 'S'); |
| Insert_Action (N, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Size, |
| Object_Definition => |
| New_Occurrence_Of (RTE (RE_Storage_Count), Loc), |
| Expression => |
| Make_Op_Divide (Loc, |
| Left_Opnd => Size_Bits, |
| Right_Opnd => Make_Integer_Literal (Loc, System_Storage_Unit)))); |
| |
| -- Calculate the alignment of the dereferenced object. Generate: |
| -- Alig : constant Storage_Count := <N>.all'Alignment; |
| |
| Deref := |
| Make_Explicit_Dereference (Loc, |
| Prefix => Duplicate_Subexpr_Move_Checks (N)); |
| Set_Has_Dereference_Action (Deref); |
| |
| Alig := Make_Temporary (Loc, 'A'); |
| Insert_Action (N, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Alig, |
| Object_Definition => |
| New_Occurrence_Of (RTE (RE_Storage_Count), Loc), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => Deref, |
| Attribute_Name => Name_Alignment))); |
| |
| -- A dereference of a controlled object requires special processing. The |
| -- finalization machinery requests additional space from the underlying |
| -- pool to allocate and hide two pointers. As a result, a checked pool |
| -- may mark the wrong memory as valid. Since checked pools do not have |
| -- knowledge of hidden pointers, we have to bring the two pointers back |
| -- in view in order to restore the original state of the object. |
| |
| -- The address manipulation is not performed for access types that are |
| -- subject to pragma No_Heap_Finalization because the two pointers do |
| -- not exist in the first place. |
| |
| if No_Heap_Finalization (Ptr_Typ) then |
| null; |
| |
| elsif Needs_Finalization (Desig_Typ) then |
| |
| -- Adjust the address and size of the dereferenced object. Generate: |
| -- Adjust_Controlled_Dereference (Addr, Size, Alig); |
| |
| Stmt := |
| Make_Procedure_Call_Statement (Loc, |
| Name => |
| New_Occurrence_Of (RTE (RE_Adjust_Controlled_Dereference), Loc), |
| Parameter_Associations => New_List ( |
| New_Occurrence_Of (Addr, Loc), |
| New_Occurrence_Of (Size, Loc), |
| New_Occurrence_Of (Alig, Loc))); |
| |
| -- Class-wide types complicate things because we cannot determine |
| -- statically whether the actual object is truly controlled. We must |
| -- generate a runtime check to detect this property. Generate: |
| -- |
| -- if Needs_Finalization (<N>.all'Tag) then |
| -- <Stmt>; |
| -- end if; |
| |
| if Is_Class_Wide_Type (Desig_Typ) then |
| Deref := |
| Make_Explicit_Dereference (Loc, |
| Prefix => Duplicate_Subexpr_Move_Checks (N)); |
| Set_Has_Dereference_Action (Deref); |
| |
| Stmt := |
| Make_Implicit_If_Statement (N, |
| Condition => |
| Make_Function_Call (Loc, |
| Name => |
| New_Occurrence_Of (RTE (RE_Needs_Finalization), Loc), |
| Parameter_Associations => New_List ( |
| Make_Attribute_Reference (Loc, |
| Prefix => Deref, |
| Attribute_Name => Name_Tag))), |
| Then_Statements => New_List (Stmt)); |
| end if; |
| |
| Insert_Action (N, Stmt); |
| end if; |
| |
| -- Generate: |
| -- Dereference (Pool, Addr, Size, Alig); |
| |
| Insert_Action (N, |
| Make_Procedure_Call_Statement (Loc, |
| Name => |
| New_Occurrence_Of |
| (Find_Prim_Op (Etype (Pool), Name_Dereference), Loc), |
| Parameter_Associations => New_List ( |
| New_Occurrence_Of (Pool, Loc), |
| New_Occurrence_Of (Addr, Loc), |
| New_Occurrence_Of (Size, Loc), |
| New_Occurrence_Of (Alig, Loc)))); |
| |
| -- Mark the explicit dereference as processed to avoid potential |
| -- infinite expansion. |
| |
| Set_Has_Dereference_Action (Context); |
| |
| exception |
| when RE_Not_Available => |
| return; |
| end Insert_Dereference_Action; |
| |
| -------------------------------- |
| -- Integer_Promotion_Possible -- |
| -------------------------------- |
| |
| function Integer_Promotion_Possible (N : Node_Id) return Boolean is |
| Operand : constant Node_Id := Expression (N); |
| Operand_Type : constant Entity_Id := Etype (Operand); |
| Root_Operand_Type : constant Entity_Id := Root_Type (Operand_Type); |
| |
| begin |
| pragma Assert (Nkind (N) = N_Type_Conversion); |
| |
| return |
| |
| -- We only do the transformation for source constructs. We assume |
| -- that the expander knows what it is doing when it generates code. |
| |
| Comes_From_Source (N) |
| |
| -- If the operand type is Short_Integer or Short_Short_Integer, |
| -- then we will promote to Integer, which is available on all |
| -- targets, and is sufficient to ensure no intermediate overflow. |
| -- Furthermore it is likely to be as efficient or more efficient |
| -- than using the smaller type for the computation so we do this |
| -- unconditionally. |
| |
| and then |
| (Root_Operand_Type = Base_Type (Standard_Short_Integer) |
| or else |
| Root_Operand_Type = Base_Type (Standard_Short_Short_Integer)) |
| |
| -- Test for interesting operation, which includes addition, |
| -- division, exponentiation, multiplication, subtraction, absolute |
| -- value and unary negation. Unary "+" is omitted since it is a |
| -- no-op and thus can't overflow. |
| |
| and then Nkind (Operand) in |
| N_Op_Abs | N_Op_Add | N_Op_Divide | N_Op_Expon | |
| N_Op_Minus | N_Op_Multiply | N_Op_Subtract; |
| end Integer_Promotion_Possible; |
| |
| ------------------------------ |
| -- Make_Array_Comparison_Op -- |
| ------------------------------ |
| |
| -- This is a hand-coded expansion of the following generic function: |
| |
| -- generic |
| -- type elem is (<>); |
| -- type index is (<>); |
| -- type a is array (index range <>) of elem; |
| |
| -- function Gnnn (X : a; Y: a) return boolean is |
| -- J : index := Y'first; |
| |
| -- begin |
| -- if X'length = 0 then |
| -- return false; |
| |
| -- elsif Y'length = 0 then |
| -- return true; |
| |
| -- else |
| -- for I in X'range loop |
| -- if X (I) = Y (J) then |
| -- if J = Y'last then |
| -- exit; |
| -- else |
| -- J := index'succ (J); |
| -- end if; |
| |
| -- else |
| -- return X (I) > Y (J); |
| -- end if; |
| -- end loop; |
| |
| -- return X'length > Y'length; |
| -- end if; |
| -- end Gnnn; |
| |
| -- Note that since we are essentially doing this expansion by hand, we |
| -- do not need to generate an actual or formal generic part, just the |
| -- instantiated function itself. |
| |
| function Make_Array_Comparison_Op |
| (Typ : Entity_Id; |
| Nod : Node_Id) return Node_Id |
| is |
| Loc : constant Source_Ptr := Sloc (Nod); |
| |
| X : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uX); |
| Y : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uY); |
| I : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uI); |
| J : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uJ); |
| |
| Index : constant Entity_Id := Base_Type (Etype (First_Index (Typ))); |
| |
| Loop_Statement : Node_Id; |
| Loop_Body : Node_Id; |
| If_Stat : Node_Id; |
| Inner_If : Node_Id; |
| Final_Expr : Node_Id; |
| Func_Body : Node_Id; |
| Func_Name : Entity_Id; |
| Formals : List_Id; |
| Length1 : Node_Id; |
| Length2 : Node_Id; |
| |
| begin |
| -- if J = Y'last then |
| -- exit; |
| -- else |
| -- J := index'succ (J); |
| -- end if; |
| |
| Inner_If := |
| Make_Implicit_If_Statement (Nod, |
| Condition => |
| Make_Op_Eq (Loc, |
| Left_Opnd => New_Occurrence_Of (J, Loc), |
| Right_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Y, Loc), |
| Attribute_Name => Name_Last)), |
| |
| Then_Statements => New_List ( |
| Make_Exit_Statement (Loc)), |
| |
| Else_Statements => |
| New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (J, Loc), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Index, Loc), |
| Attribute_Name => Name_Succ, |
| Expressions => New_List (New_Occurrence_Of (J, Loc)))))); |
| |
| -- if X (I) = Y (J) then |
| -- if ... end if; |
| -- else |
| -- return X (I) > Y (J); |
| -- end if; |
| |
| Loop_Body := |
| Make_Implicit_If_Statement (Nod, |
| Condition => |
| Make_Op_Eq (Loc, |
| Left_Opnd => |
| Make_Indexed_Component (Loc, |
| Prefix => New_Occurrence_Of (X, Loc), |
| Expressions => New_List (New_Occurrence_Of (I, Loc))), |
| |
| Right_Opnd => |
| Make_Indexed_Component (Loc, |
| Prefix => New_Occurrence_Of (Y, Loc), |
| Expressions => New_List (New_Occurrence_Of (J, Loc)))), |
| |
| Then_Statements => New_List (Inner_If), |
| |
| Else_Statements => New_List ( |
| Make_Simple_Return_Statement (Loc, |
| Expression => |
| Make_Op_Gt (Loc, |
| Left_Opnd => |
| Make_Indexed_Component (Loc, |
| Prefix => New_Occurrence_Of (X, Loc), |
| Expressions => New_List (New_Occurrence_Of (I, Loc))), |
| |
| Right_Opnd => |
| Make_Indexed_Component (Loc, |
| Prefix => New_Occurrence_Of (Y, Loc), |
| Expressions => New_List ( |
| New_Occurrence_Of (J, Loc))))))); |
| |
| -- for I in X'range loop |
| -- if ... end if; |
| -- end loop; |
| |
| Loop_Statement := |
| Make_Implicit_Loop_Statement (Nod, |
| Identifier => Empty, |
| |
| Iteration_Scheme => |
| Make_Iteration_Scheme (Loc, |
| Loop_Parameter_Specification => |
| Make_Loop_Parameter_Specification (Loc, |
| Defining_Identifier => I, |
| Discrete_Subtype_Definition => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (X, Loc), |
| Attribute_Name => Name_Range))), |
| |
| Statements => New_List (Loop_Body)); |
| |
| -- if X'length = 0 then |
| -- return false; |
| -- elsif Y'length = 0 then |
| -- return true; |
| -- else |
| -- for ... loop ... end loop; |
| -- return X'length > Y'length; |
| -- end if; |
| |
| Length1 := |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (X, Loc), |
| Attribute_Name => Name_Length); |
| |
| Length2 := |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Y, Loc), |
| Attribute_Name => Name_Length); |
| |
| Final_Expr := |
| Make_Op_Gt (Loc, |
| Left_Opnd => Length1, |
| Right_Opnd => Length2); |
| |
| If_Stat := |
| Make_Implicit_If_Statement (Nod, |
| Condition => |
| Make_Op_Eq (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (X, Loc), |
| Attribute_Name => Name_Length), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, 0)), |
| |
| Then_Statements => |
| New_List ( |
| Make_Simple_Return_Statement (Loc, |
| Expression => New_Occurrence_Of (Standard_False, Loc))), |
| |
| Elsif_Parts => New_List ( |
| Make_Elsif_Part (Loc, |
| Condition => |
| Make_Op_Eq (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Y, Loc), |
| Attribute_Name => Name_Length), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, 0)), |
| |
| Then_Statements => |
| New_List ( |
| Make_Simple_Return_Statement (Loc, |
| Expression => New_Occurrence_Of (Standard_True, Loc))))), |
| |
| Else_Statements => New_List ( |
| Loop_Statement, |
| Make_Simple_Return_Statement (Loc, |
| Expression => Final_Expr))); |
| |
| -- (X : a; Y: a) |
| |
| Formals := New_List ( |
| Make_Parameter_Specification (Loc, |
| Defining_Identifier => X, |
| Parameter_Type => New_Occurrence_Of (Typ, Loc)), |
| |
| Make_Parameter_Specification (Loc, |
| Defining_Identifier => Y, |
| Parameter_Type => New_Occurrence_Of (Typ, Loc))); |
| |
| -- function Gnnn (...) return boolean is |
| -- J : index := Y'first; |
| -- begin |
| -- if ... end if; |
| -- end Gnnn; |
| |
| Func_Name := Make_Temporary (Loc, 'G'); |
| |
| Func_Body := |
| Make_Subprogram_Body (Loc, |
| Specification => |
| Make_Function_Specification (Loc, |
| Defining_Unit_Name => Func_Name, |
| Parameter_Specifications => Formals, |
| Result_Definition => New_Occurrence_Of (Standard_Boolean, Loc)), |
| |
| Declarations => New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => J, |
| Object_Definition => New_Occurrence_Of (Index, Loc), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Y, Loc), |
| Attribute_Name => Name_First))), |
| |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List (If_Stat))); |
| |
| return Func_Body; |
| end Make_Array_Comparison_Op; |
| |
| --------------------------- |
| -- Make_Boolean_Array_Op -- |
| --------------------------- |
| |
| -- For logical operations on boolean arrays, expand in line the following, |
| -- replacing 'and' with 'or' or 'xor' where needed: |
| |
| -- function Annn (A : typ; B: typ) return typ is |
| -- C : typ; |
| -- begin |
| -- for J in A'range loop |
| -- C (J) := A (J) op B (J); |
| -- end loop; |
| -- return C; |
| -- end Annn; |
| |
| -- or in the case of Transform_Function_Array: |
| |
| -- procedure Annn (A : typ; B: typ; RESULT: out typ) is |
| -- begin |
| -- for J in A'range loop |
| -- RESULT (J) := A (J) op B (J); |
| -- end loop; |
| -- end Annn; |
| |
| -- Here typ is the boolean array type |
| |
| function Make_Boolean_Array_Op |
| (Typ : Entity_Id; |
| N : Node_Id) return Node_Id |
| is |
| Loc : constant Source_Ptr := Sloc (N); |
| |
| A : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uA); |
| B : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uB); |
| J : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uJ); |
| |
| C : Entity_Id; |
| |
| A_J : Node_Id; |
| B_J : Node_Id; |
| C_J : Node_Id; |
| Op : Node_Id; |
| |
| Formals : List_Id; |
| Func_Name : Entity_Id; |
| Func_Body : Node_Id; |
| Loop_Statement : Node_Id; |
| |
| begin |
| if Transform_Function_Array then |
| C := Make_Defining_Identifier (Loc, Name_UP_RESULT); |
| else |
| C := Make_Defining_Identifier (Loc, Name_uC); |
| end if; |
| |
| A_J := |
| Make_Indexed_Component (Loc, |
| Prefix => New_Occurrence_Of (A, Loc), |
| Expressions => New_List (New_Occurrence_Of (J, Loc))); |
| |
| B_J := |
| Make_Indexed_Component (Loc, |
| Prefix => New_Occurrence_Of (B, Loc), |
| Expressions => New_List (New_Occurrence_Of (J, Loc))); |
| |
| C_J := |
| Make_Indexed_Component (Loc, |
| Prefix => New_Occurrence_Of (C, Loc), |
| Expressions => New_List (New_Occurrence_Of (J, Loc))); |
| |
| if Nkind (N) = N_Op_And then |
| Op := |
| Make_Op_And (Loc, |
| Left_Opnd => A_J, |
| Right_Opnd => B_J); |
| |
| elsif Nkind (N) = N_Op_Or then |
| Op := |
| Make_Op_Or (Loc, |
| Left_Opnd => A_J, |
| Right_Opnd => B_J); |
| |
| else |
| Op := |
| Make_Op_Xor (Loc, |
| Left_Opnd => A_J, |
| Right_Opnd => B_J); |
| end if; |
| |
| Loop_Statement := |
| Make_Implicit_Loop_Statement (N, |
| Identifier => Empty, |
| |
| Iteration_Scheme => |
| Make_Iteration_Scheme (Loc, |
| Loop_Parameter_Specification => |
| Make_Loop_Parameter_Specification (Loc, |
| Defining_Identifier => J, |
| Discrete_Subtype_Definition => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (A, Loc), |
| Attribute_Name => Name_Range))), |
| |
| Statements => New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => C_J, |
| Expression => Op))); |
| |
| Formals := New_List ( |
| Make_Parameter_Specification (Loc, |
| Defining_Identifier => A, |
| Parameter_Type => New_Occurrence_Of (Typ, Loc)), |
| |
| Make_Parameter_Specification (Loc, |
| Defining_Identifier => B, |
| Parameter_Type => New_Occurrence_Of (Typ, Loc))); |
| |
| if Transform_Function_Array then |
| Append_To (Formals, |
| Make_Parameter_Specification (Loc, |
| Defining_Identifier => C, |
| Out_Present => True, |
| Parameter_Type => New_Occurrence_Of (Typ, Loc))); |
| end if; |
| |
| Func_Name := Make_Temporary (Loc, 'A'); |
| Set_Is_Inlined (Func_Name); |
| |
| if Transform_Function_Array then |
| Func_Body := |
| Make_Subprogram_Body (Loc, |
| Specification => |
| Make_Procedure_Specification (Loc, |
| Defining_Unit_Name => Func_Name, |
| Parameter_Specifications => Formals), |
| |
| Declarations => New_List, |
| |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List (Loop_Statement))); |
| |
| else |
| Func_Body := |
| Make_Subprogram_Body (Loc, |
| Specification => |
| Make_Function_Specification (Loc, |
| Defining_Unit_Name => Func_Name, |
| Parameter_Specifications => Formals, |
| Result_Definition => New_Occurrence_Of (Typ, Loc)), |
| |
| Declarations => New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => C, |
| Object_Definition => New_Occurrence_Of (Typ, Loc))), |
| |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List ( |
| Loop_Statement, |
| Make_Simple_Return_Statement (Loc, |
| Expression => New_Occurrence_Of (C, Loc))))); |
| end if; |
| |
| return Func_Body; |
| end Make_Boolean_Array_Op; |
| |
| ----------------------------------------- |
| -- Minimized_Eliminated_Overflow_Check -- |
| ----------------------------------------- |
| |
| function Minimized_Eliminated_Overflow_Check (N : Node_Id) return Boolean is |
| begin |
| -- The MINIMIZED mode operates in Long_Long_Integer so we cannot use it |
| -- if the type of the expression is already larger. |
| |
| return |
| Is_Signed_Integer_Type (Etype (N)) |
| and then Overflow_Check_Mode in Minimized_Or_Eliminated |
| and then not (Overflow_Check_Mode = Minimized |
| and then |
| Esize (Etype (N)) > Standard_Long_Long_Integer_Size); |
| end Minimized_Eliminated_Overflow_Check; |
| |
| ---------------------------- |
| -- Narrow_Large_Operation -- |
| ---------------------------- |
| |
| procedure Narrow_Large_Operation (N : Node_Id) is |
| Kind : constant Node_Kind := Nkind (N); |
| Otyp : constant Entity_Id := Etype (N); |
| In_Rng : constant Boolean := Kind = N_In; |
| Binary : constant Boolean := Kind in N_Binary_Op or else In_Rng; |
| Compar : constant Boolean := Kind in N_Op_Compare or else In_Rng; |
| R : constant Node_Id := Right_Opnd (N); |
| Typ : constant Entity_Id := Etype (R); |
| Tsiz : constant Uint := RM_Size (Typ); |
| |
| -- Local variables |
| |
| L : Node_Id; |
| Llo, Lhi : Uint; |
| Rlo, Rhi : Uint; |
| Lsiz, Rsiz : Uint; |
| Nlo, Nhi : Uint; |
| Nsiz : Uint; |
| Ntyp : Entity_Id; |
| Nop : Node_Id; |
| OK : Boolean; |
| |
| -- Start of processing for Narrow_Large_Operation |
| |
| begin |
| -- First, determine the range of the left operand, if any |
| |
| if Binary then |
| L := Left_Opnd (N); |
| Determine_Range (L, OK, Llo, Lhi, Assume_Valid => True); |
| if not OK then |
| return; |
| end if; |
| |
| else |
| L := Empty; |
| Llo := Uint_0; |
| Lhi := Uint_0; |
| end if; |
| |
| -- Second, determine the range of the right operand, which can itself |
| -- be a range, in which case we take the lower bound of the low bound |
| -- and the upper bound of the high bound. |
| |
| if In_Rng then |
| declare |
| Zlo, Zhi : Uint; |
| |
| begin |
| Determine_Range |
| (Low_Bound (R), OK, Rlo, Zhi, Assume_Valid => True); |
| if not OK then |
| return; |
| end if; |
| |
| Determine_Range |
| (High_Bound (R), OK, Zlo, Rhi, Assume_Valid => True); |
| if not OK then |
| return; |
| end if; |
| end; |
| |
| else |
| Determine_Range (R, OK, Rlo, Rhi, Assume_Valid => True); |
| if not OK then |
| return; |
| end if; |
| end if; |
| |
| -- Then compute a size suitable for each range |
| |
| if Binary then |
| Lsiz := Get_Size_For_Range (Llo, Lhi); |
| else |
| Lsiz := Uint_0; |
| end if; |
| |
| Rsiz := Get_Size_For_Range (Rlo, Rhi); |
| |
| -- Now compute the size of the narrower type |
| |
| if Compar then |
| -- The type must be able to accommodate the operands |
| |
| Nsiz := UI_Max (Lsiz, Rsiz); |
| |
| else |
| -- The type must be able to accommodate the operand(s) and result. |
| |
| -- Note that Determine_Range typically does not report the bounds of |
| -- the value as being larger than those of the base type, which means |
| -- that it does not report overflow (see also Enable_Overflow_Check). |
| |
| Determine_Range (N, OK, Nlo, Nhi, Assume_Valid => True); |
| if not OK then |
| return; |
| end if; |
| |
| -- Therefore, if Nsiz is not lower than the size of the original type |
| -- here, we cannot be sure that the operation does not overflow. |
| |
| Nsiz := Get_Size_For_Range (Nlo, Nhi); |
| Nsiz := UI_Max (Nsiz, Lsiz); |
| Nsiz := UI_Max (Nsiz, Rsiz); |
| end if; |
| |
| -- If the size is not lower than the size of the original type, then |
| -- there is no point in changing the type, except in the case where |
| -- we can remove a conversion to the original type from an operand. |
| |
| if Nsiz >= Tsiz |
| and then not (Binary |
| and then Nkind (L) = N_Type_Conversion |
| and then Entity (Subtype_Mark (L)) = Typ) |
| and then not (Nkind (R) = N_Type_Conversion |
| and then Entity (Subtype_Mark (R)) = Typ) |
| then |
| return; |
| end if; |
| |
| -- Now pick the narrower type according to the size. We use the base |
| -- type instead of the first subtype because operations are done in |
| -- the base type, so this avoids the need for useless conversions. |
| |
| if Nsiz <= System_Max_Integer_Size then |
| Ntyp := Etype (Integer_Type_For (Nsiz, Uns => False)); |
| else |
| return; |
| end if; |
| |
| -- Finally, rewrite the operation in the narrower type, but make sure |
| -- not to perform name resolution for the operator again. |
| |
| Nop := New_Op_Node (Kind, Sloc (N)); |
| if Nkind (N) in N_Has_Entity then |
| Set_Entity (Nop, Entity (N)); |
| end if; |
| |
| if Binary then |
| Set_Left_Opnd (Nop, Convert_To (Ntyp, L)); |
| end if; |
| |
| if In_Rng then |
| Set_Right_Opnd (Nop, |
| Make_Range (Sloc (N), |
| Convert_To (Ntyp, Low_Bound (R)), |
| Convert_To (Ntyp, High_Bound (R)))); |
| else |
| Set_Right_Opnd (Nop, Convert_To (Ntyp, R)); |
| end if; |
| |
| Rewrite (N, Nop); |
| |
| if Compar then |
| -- Analyze it with the comparison type and checks suppressed since |
| -- the conversions of the operands cannot overflow. |
| |
| Analyze_And_Resolve (N, Otyp, Suppress => Overflow_Check); |
| |
| else |
| -- Analyze it with the narrower type and checks suppressed, but only |
| -- when we are sure that the operation does not overflow, see above. |
| |
| if Nsiz < Tsiz then |
| Analyze_And_Resolve (N, Ntyp, Suppress => Overflow_Check); |
| else |
| Analyze_And_Resolve (N, Ntyp); |
| end if; |
| |
| -- Put back a conversion to the original type |
| |
| Convert_To_And_Rewrite (Typ, N); |
| end if; |
| end Narrow_Large_Operation; |
| |
| -------------------------------- |
| -- Optimize_Length_Comparison -- |
| -------------------------------- |
| |
| procedure Optimize_Length_Comparison (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| Result : Node_Id; |
| |
| Left : Node_Id; |
| Right : Node_Id; |
| -- First and Last attribute reference nodes, which end up as left and |
| -- right operands of the optimized result. |
| |
| Is_Zero : Boolean; |
| -- True for comparison operand of zero |
| |
| Maybe_Superflat : Boolean; |
| -- True if we may be in the dynamic superflat case, i.e. Is_Zero is set |
| -- to false but the comparison operand can be zero at run time. In this |
| -- case, we normally cannot do anything because the canonical formula of |
| -- the length is not valid, but there is one exception: when the operand |
| -- is itself the length of an array with the same bounds as the array on |
| -- the LHS, we can entirely optimize away the comparison. |
| |
| Comp : Node_Id; |
| -- Comparison operand, set only if Is_Zero is false |
| |
| Ent : array (Pos range 1 .. 2) of Entity_Id := (Empty, Empty); |
| -- Entities whose length is being compared |
| |
| Index : array (Pos range 1 .. 2) of Node_Id := (Empty, Empty); |
| -- Integer_Literal nodes for length attribute expressions, or Empty |
| -- if there is no such expression present. |
| |
| Op : Node_Kind := Nkind (N); |
| -- Kind of comparison operator, gets flipped if operands backwards |
| |
| function Convert_To_Long_Long_Integer (N : Node_Id) return Node_Id; |
| -- Given a discrete expression, returns a Long_Long_Integer typed |
| -- expression representing the underlying value of the expression. |
| -- This is done with an unchecked conversion to Long_Long_Integer. |
| -- We use unchecked conversion to handle the enumeration type case. |
| |
| function Is_Entity_Length (N : Node_Id; Num : Pos) return Boolean; |
| -- Tests if N is a length attribute applied to a simple entity. If so, |
| -- returns True, and sets Ent to the entity, and Index to the integer |
| -- literal provided as an attribute expression, or to Empty if none. |
| -- Num is the index designating the relevant slot in Ent and Index. |
| -- Also returns True if the expression is a generated type conversion |
| -- whose expression is of the desired form. This latter case arises |
| -- when Apply_Universal_Integer_Attribute_Check installs a conversion |
| -- to check for being in range, which is not needed in this context. |
| -- Returns False if neither condition holds. |
| |
| function Is_Optimizable (N : Node_Id) return Boolean; |
| -- Tests N to see if it is an optimizable comparison value (defined as |
| -- constant zero or one, or something else where the value is known to |
| -- be nonnegative and in the 32-bit range and where the corresponding |
| -- Length value is also known to be 32 bits). If result is true, sets |
| -- Is_Zero, Maybe_Superflat and Comp accordingly. |
| |
| procedure Rewrite_For_Equal_Lengths; |
| -- Rewrite the comparison of two equal lengths into either True or False |
| |
| ---------------------------------- |
| -- Convert_To_Long_Long_Integer -- |
| ---------------------------------- |
| |
| function Convert_To_Long_Long_Integer (N : Node_Id) return Node_Id is |
| begin |
| return Unchecked_Convert_To (Standard_Long_Long_Integer, N); |
| end Convert_To_Long_Long_Integer; |
| |
| ---------------------- |
| -- Is_Entity_Length -- |
| ---------------------- |
| |
| function Is_Entity_Length (N : Node_Id; Num : Pos) return Boolean is |
| begin |
| if Nkind (N) = N_Attribute_Reference |
| and then Attribute_Name (N) = Name_Length |
| and then Is_Entity_Name (Prefix (N)) |
| then |
| Ent (Num) := Entity (Prefix (N)); |
| |
| if Present (Expressions (N)) then |
| Index (Num) := First (Expressions (N)); |
| else |
| Index (Num) := Empty; |
| end if; |
| |
| return True; |
| |
| elsif Nkind (N) = N_Type_Conversion |
| and then not Comes_From_Source (N) |
| then |
| return Is_Entity_Length (Expression (N), Num); |
| |
| else |
| return False; |
| end if; |
| end Is_Entity_Length; |
| |
| -------------------- |
| -- Is_Optimizable -- |
| -------------------- |
| |
| function Is_Optimizable (N : Node_Id) return Boolean is |
| Val : Uint; |
| OK : Boolean; |
| Lo : Uint; |
| Hi : Uint; |
| Indx : Node_Id; |
| Dbl : Boolean; |
| Ityp : Entity_Id; |
| |
| begin |
| if Compile_Time_Known_Value (N) then |
| Val := Expr_Value (N); |
| |
| if Val = Uint_0 then |
| Is_Zero := True; |
| Maybe_Superflat := False; |
| Comp := Empty; |
| return True; |
| |
| elsif Val = Uint_1 then |
| Is_Zero := False; |
| Maybe_Superflat := False; |
| Comp := Empty; |
| return True; |
| end if; |
| end if; |
| |
| -- Here we have to make sure of being within a 32-bit range (take the |
| -- full unsigned range so the length of 32-bit arrays is accepted). |
| |
| Determine_Range (N, OK, Lo, Hi, Assume_Valid => True); |
| |
| if not OK |
| or else Lo < Uint_0 |
| or else Hi > Uint_2 ** 32 |
| then |
| return False; |
| end if; |
| |
| Maybe_Superflat := (Lo = Uint_0); |
| |
| -- Tests if N is also a length attribute applied to a simple entity |
| |
| Dbl := Is_Entity_Length (N, 2); |
| |
| -- We can deal with the superflat case only if N is also a length |
| |
| if Maybe_Superflat and then not Dbl then |
| return False; |
| end if; |
| |
| -- Comparison value was within range, so now we must check the index |
| -- value to make sure it is also within 32 bits. |
| |
| for K in Pos range 1 .. 2 loop |
| Indx := First_Index (Etype (Ent (K))); |
| |
| if Present (Index (K)) then |
| for J in 2 .. UI_To_Int (Intval (Index (K))) loop |
| Next_Index (Indx); |
| end loop; |
| end if; |
| |
| Ityp := Etype (Indx); |
| |
| if Esize (Ityp) > 32 then |
| return False; |
| end if; |
| |
| exit when not Dbl; |
| end loop; |
| |
| Is_Zero := False; |
| Comp := N; |
| return True; |
| end Is_Optimizable; |
| |
| ------------------------------- |
| -- Rewrite_For_Equal_Lengths -- |
| ------------------------------- |
| |
| procedure Rewrite_For_Equal_Lengths is |
| begin |
| case Op is |
| when N_Op_Eq |
| | N_Op_Ge |
| | N_Op_Le |
| => |
| Rewrite (N, |
| Convert_To (Typ, |
| New_Occurrence_Of (Standard_True, Sloc (N)))); |
| |
| when N_Op_Ne |
| | N_Op_Gt |
| | N_Op_Lt |
| => |
| Rewrite (N, |
| Convert_To (Typ, |
| New_Occurrence_Of (Standard_False, Sloc (N)))); |
| |
| when others => |
| raise Program_Error; |
| end case; |
| |
| Analyze_And_Resolve (N, Typ); |
| end Rewrite_For_Equal_Lengths; |
| |
| -- Start of processing for Optimize_Length_Comparison |
| |
| begin |
| -- Nothing to do if not a comparison |
| |
| if Op not in N_Op_Compare then |
| return; |
| end if; |
| |
| -- Nothing to do if special -gnatd.P debug flag set. |
| |
| if Debug_Flag_Dot_PP then |
| return; |
| end if; |
| |
| -- Ent'Length op 0/1 |
| |
| if Is_Entity_Length (Left_Opnd (N), 1) |
| and then Is_Optimizable (Right_Opnd (N)) |
| then |
| null; |
| |
| -- 0/1 op Ent'Length |
| |
| elsif Is_Entity_Length (Right_Opnd (N), 1) |
| and then Is_Optimizable (Left_Opnd (N)) |
| then |
| -- Flip comparison to opposite sense |
| |
| case Op is |
| when N_Op_Lt => Op := N_Op_Gt; |
| when N_Op_Le => Op := N_Op_Ge; |
| when N_Op_Gt => Op := N_Op_Lt; |
| when N_Op_Ge => Op := N_Op_Le; |
| when others => null; |
| end case; |
| |
| -- Else optimization not possible |
| |
| else |
| return; |
| end if; |
| |
| -- Fall through if we will do the optimization |
| |
| -- Cases to handle: |
| |
| -- X'Length = 0 => X'First > X'Last |
| -- X'Length = 1 => X'First = X'Last |
| -- X'Length = n => X'First + (n - 1) = X'Last |
| |
| -- X'Length /= 0 => X'First <= X'Last |
| -- X'Length /= 1 => X'First /= X'Last |
| -- X'Length /= n => X'First + (n - 1) /= X'Last |
| |
| -- X'Length >= 0 => always true, warn |
| -- X'Length >= 1 => X'First <= X'Last |
| -- X'Length >= n => X'First + (n - 1) <= X'Last |
| |
| -- X'Length > 0 => X'First <= X'Last |
| -- X'Length > 1 => X'First < X'Last |
| -- X'Length > n => X'First + (n - 1) < X'Last |
| |
| -- X'Length <= 0 => X'First > X'Last (warn, could be =) |
| -- X'Length <= 1 => X'First >= X'Last |
| -- X'Length <= n => X'First + (n - 1) >= X'Last |
| |
| -- X'Length < 0 => always false (warn) |
| -- X'Length < 1 => X'First > X'Last |
| -- X'Length < n => X'First + (n - 1) > X'Last |
| |
| -- Note: for the cases of n (not constant 0,1), we require that the |
| -- corresponding index type be integer or shorter (i.e. not 64-bit), |
| -- and the same for the comparison value. Then we do the comparison |
| -- using 64-bit arithmetic (actually long long integer), so that we |
| -- cannot have overflow intefering with the result. |
| |
| -- First deal with warning cases |
| |
| if Is_Zero then |
| case Op is |
| |
| -- X'Length >= 0 |
| |
| when N_Op_Ge => |
| Rewrite (N, |
| Convert_To (Typ, New_Occurrence_Of (Standard_True, Loc))); |
| Analyze_And_Resolve (N, Typ); |
| Warn_On_Known_Condition (N); |
| return; |
| |
| -- X'Length < 0 |
| |
| when N_Op_Lt => |
| Rewrite (N, |
| Convert_To (Typ, New_Occurrence_Of (Standard_False, Loc))); |
| Analyze_And_Resolve (N, Typ); |
| Warn_On_Known_Condition (N); |
| return; |
| |
| when N_Op_Le => |
| if Constant_Condition_Warnings |
| and then Comes_From_Source (Original_Node (N)) |
| then |
| Error_Msg_N ("could replace by ""'=""?c?", N); |
| end if; |
| |
| Op := N_Op_Eq; |
| |
| when others => |
| null; |
| end case; |
| end if; |
| |
| -- Build the First reference we will use |
| |
| Left := |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Ent (1), Loc), |
| Attribute_Name => Name_First); |
| |
| if Present (Index (1)) then |
| Set_Expressions (Left, New_List (New_Copy (Index (1)))); |
| end if; |
| |
| -- Build the Last reference we will use |
| |
| Right := |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Ent (1), Loc), |
| Attribute_Name => Name_Last); |
| |
| if Present (Index (1)) then |
| Set_Expressions (Right, New_List (New_Copy (Index (1)))); |
| end if; |
| |
| -- If general value case, then do the addition of (n - 1), and |
| -- also add the needed conversions to type Long_Long_Integer. |
| |
| -- If n = Y'Length, we rewrite X'First + (n - 1) op X'Last into: |
| |
| -- Y'Last + (X'First - Y'First) op X'Last |
| |
| -- in the hope that X'First - Y'First can be computed statically. |
| |
| if Present (Comp) then |
| if Present (Ent (2)) then |
| declare |
| Y_First : constant Node_Id := |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Ent (2), Loc), |
| Attribute_Name => Name_First); |
| Y_Last : constant Node_Id := |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Ent (2), Loc), |
| Attribute_Name => Name_Last); |
| R : Compare_Result; |
| |
| begin |
| if Present (Index (2)) then |
| Set_Expressions (Y_First, New_List (New_Copy (Index (2)))); |
| Set_Expressions (Y_Last, New_List (New_Copy (Index (2)))); |
| end if; |
| |
| Analyze (Left); |
| Analyze (Y_First); |
| |
| -- If X'First = Y'First, simplify the above formula into a |
| -- direct comparison of Y'Last and X'Last. |
| |
| R := Compile_Time_Compare (Left, Y_First, Assume_Valid => True); |
| |
| if R = EQ then |
| Analyze (Right); |
| Analyze (Y_Last); |
| |
| R := Compile_Time_Compare |
| (Right, Y_Last, Assume_Valid => True); |
| |
| -- If the pairs of attributes are equal, we are done |
| |
| if R = EQ then |
| Rewrite_For_Equal_Lengths; |
| return; |
| end if; |
| |
| -- If the base types are different, convert both operands to |
| -- Long_Long_Integer, else compare them directly. |
| |
| if Base_Type (Etype (Right)) /= Base_Type (Etype (Y_Last)) |
| then |
| Left := Convert_To_Long_Long_Integer (Y_Last); |
| else |
| Left := Y_Last; |
| Comp := Empty; |
| end if; |
| |
| -- Otherwise, use the above formula as-is |
| |
| else |
| Left := |
| Make_Op_Add (Loc, |
| Left_Opnd => |
| Convert_To_Long_Long_Integer (Y_Last), |
| Right_Opnd => |
| Make_Op_Subtract (Loc, |
| Left_Opnd => |
| Convert_To_Long_Long_Integer (Left), |
| Right_Opnd => |
| Convert_To_Long_Long_Integer (Y_First))); |
| end if; |
| end; |
| |
| -- General value case |
| |
| else |
| Left := |
| Make_Op_Add (Loc, |
| Left_Opnd => Convert_To_Long_Long_Integer (Left), |
| Right_Opnd => |
| Make_Op_Subtract (Loc, |
| Left_Opnd => Convert_To_Long_Long_Integer (Comp), |
| Right_Opnd => Make_Integer_Literal (Loc, 1))); |
| end if; |
| end if; |
| |
| -- We cannot do anything in the superflat case past this point |
| |
| if Maybe_Superflat then |
| return; |
| end if; |
| |
| -- If general operand, convert Last reference to Long_Long_Integer |
| |
| if Present (Comp) then |
| Right := Convert_To_Long_Long_Integer (Right); |
| end if; |
| |
| -- Check for cases to optimize |
| |
| -- X'Length = 0 => X'First > X'Last |
| -- X'Length < 1 => X'First > X'Last |
| -- X'Length < n => X'First + (n - 1) > X'Last |
| |
| if (Is_Zero and then Op = N_Op_Eq) |
| or else (not Is_Zero and then Op = N_Op_Lt) |
| then |
| Result := |
| Make_Op_Gt (Loc, |
| Left_Opnd => Left, |
| Right_Opnd => Right); |
| |
| -- X'Length = 1 => X'First = X'Last |
| -- X'Length = n => X'First + (n - 1) = X'Last |
| |
| elsif not Is_Zero and then Op = N_Op_Eq then |
| Result := |
| Make_Op_Eq (Loc, |
| Left_Opnd => Left, |
| Right_Opnd => Right); |
| |
| -- X'Length /= 0 => X'First <= X'Last |
| -- X'Length > 0 => X'First <= X'Last |
| |
| elsif Is_Zero and (Op = N_Op_Ne or else Op = N_Op_Gt) then |
| Result := |
| Make_Op_Le (Loc, |
| Left_Opnd => Left, |
| Right_Opnd => Right); |
| |
| -- X'Length /= 1 => X'First /= X'Last |
| -- X'Length /= n => X'First + (n - 1) /= X'Last |
| |
| elsif not Is_Zero and then Op = N_Op_Ne then |
| Result := |
| Make_Op_Ne (Loc, |
| Left_Opnd => Left, |
| Right_Opnd => Right); |
| |
| -- X'Length >= 1 => X'First <= X'Last |
| -- X'Length >= n => X'First + (n - 1) <= X'Last |
| |
| elsif not Is_Zero and then Op = N_Op_Ge then |
| Result := |
| Make_Op_Le (Loc, |
| Left_Opnd => Left, |
| Right_Opnd => Right); |
| |
| -- X'Length > 1 => X'First < X'Last |
| -- X'Length > n => X'First + (n = 1) < X'Last |
| |
| elsif not Is_Zero and then Op = N_Op_Gt then |
| Result := |
| Make_Op_Lt (Loc, |
| Left_Opnd => Left, |
| Right_Opnd => Right); |
| |
| -- X'Length <= 1 => X'First >= X'Last |
| -- X'Length <= n => X'First + (n - 1) >= X'Last |
| |
| elsif not Is_Zero and then Op = N_Op_Le then |
| Result := |
| Make_Op_Ge (Loc, |
| Left_Opnd => Left, |
| Right_Opnd => Right); |
| |
| -- Should not happen at this stage |
| |
| else |
| raise Program_Error; |
| end if; |
| |
| -- Rewrite and finish up (we can suppress overflow checks, see above) |
| |
| Rewrite (N, Result); |
| Analyze_And_Resolve (N, Typ, Suppress => Overflow_Check); |
| end Optimize_Length_Comparison; |
| |
| -------------------------------- |
| -- Process_If_Case_Statements -- |
| -------------------------------- |
| |
| procedure Process_If_Case_Statements (N : Node_Id; Stmts : List_Id) is |
| Decl : Node_Id; |
| |
| begin |
| Decl := First (Stmts); |
| while Present (Decl) loop |
| if Nkind (Decl) = N_Object_Declaration |
| and then Is_Finalizable_Transient (Decl, N) |
| then |
| Process_Transient_In_Expression (Decl, N, Stmts); |
| end if; |
| |
| Next (Decl); |
| end loop; |
| end Process_If_Case_Statements; |
| |
| ------------------------------------- |
| -- Process_Transient_In_Expression -- |
| ------------------------------------- |
| |
| procedure Process_Transient_In_Expression |
| (Obj_Decl : Node_Id; |
| Expr : Node_Id; |
| Stmts : List_Id) |
| is |
| Loc : constant Source_Ptr := Sloc (Obj_Decl); |
| Obj_Id : constant Entity_Id := Defining_Identifier (Obj_Decl); |
| |
| Hook_Context : constant Node_Id := Find_Hook_Context (Expr); |
| -- The node on which to insert the hook as an action. This is usually |
| -- the innermost enclosing non-transient construct. |
| |
| Fin_Call : Node_Id; |
| Hook_Assign : Node_Id; |
| Hook_Clear : Node_Id; |
| Hook_Decl : Node_Id; |
| Hook_Insert : Node_Id; |
| Ptr_Decl : Node_Id; |
| |
| Fin_Context : Node_Id; |
| -- The node after which to insert the finalization actions of the |
| -- transient object. |
| |
| begin |
| pragma Assert (Nkind (Expr) in N_Case_Expression |
| | N_Expression_With_Actions |
| | N_If_Expression); |
| |
| -- When the context is a Boolean evaluation, all three nodes capture the |
| -- result of their computation in a local temporary: |
| |
| -- do |
| -- Trans_Id : Ctrl_Typ := ...; |
| -- Result : constant Boolean := ... Trans_Id ...; |
| -- <finalize Trans_Id> |
| -- in Result end; |
| |
| -- As a result, the finalization of any transient objects can safely |
| -- take place after the result capture. |
| |
| -- ??? could this be extended to elementary types? |
| |
| if Is_Boolean_Type (Etype (Expr)) then |
| Fin_Context := Last (Stmts); |
| |
| -- Otherwise the immediate context may not be safe enough to carry |
| -- out transient object finalization due to aliasing and nesting of |
| -- constructs. Insert calls to [Deep_]Finalize after the innermost |
| -- enclosing non-transient construct. |
| |
| else |
| Fin_Context := Hook_Context; |
| end if; |
| |
| -- Mark the transient object as successfully processed to avoid double |
| -- finalization. |
| |
| Set_Is_Finalized_Transient (Obj_Id); |
| |
| -- Construct all the pieces necessary to hook and finalize a transient |
| -- object. |
| |
| Build_Transient_Object_Statements |
| (Obj_Decl => Obj_Decl, |
| Fin_Call => Fin_Call, |
| Hook_Assign => Hook_Assign, |
| Hook_Clear => Hook_Clear, |
| Hook_Decl => Hook_Decl, |
| Ptr_Decl => Ptr_Decl, |
| Finalize_Obj => False); |
| |
| -- Add the access type which provides a reference to the transient |
| -- object. Generate: |
| |
| -- type Ptr_Typ is access all Desig_Typ; |
| |
| Insert_Action (Hook_Context, Ptr_Decl); |
| |
| -- Add the temporary which acts as a hook to the transient object. |
| -- Generate: |
| |
| -- Hook : Ptr_Id := null; |
| |
| Insert_Action (Hook_Context, Hook_Decl); |
| |
| -- When the transient object is initialized by an aggregate, the hook |
| -- must capture the object after the last aggregate assignment takes |
| -- place. Only then is the object considered initialized. Generate: |
| |
| -- Hook := Ptr_Typ (Obj_Id); |
| -- <or> |
| -- Hook := Obj_Id'Unrestricted_Access; |
| |
| if Ekind (Obj_Id) in E_Constant | E_Variable |
| and then Present (Last_Aggregate_Assignment (Obj_Id)) |
| then |
| Hook_Insert := Last_Aggregate_Assignment (Obj_Id); |
| |
| -- Otherwise the hook seizes the related object immediately |
| |
| else |
| Hook_Insert := Obj_Decl; |
| end if; |
| |
| Insert_After_And_Analyze (Hook_Insert, Hook_Assign); |
| |
| -- When the node is part of a return statement, there is no need to |
| -- insert a finalization call, as the general finalization mechanism |
| -- (see Build_Finalizer) would take care of the transient object on |
| -- subprogram exit. Note that it would also be impossible to insert the |
| -- finalization code after the return statement as this will render it |
| -- unreachable. |
| |
| if Nkind (Fin_Context) = N_Simple_Return_Statement then |
| null; |
| |
| -- Finalize the hook after the context has been evaluated. Generate: |
| |
| -- if Hook /= null then |
| -- [Deep_]Finalize (Hook.all); |
| -- Hook := null; |
| -- end if; |
| |
| -- Note that the value returned by Find_Hook_Context may be an operator |
| -- node, which is not a list member. We must locate the proper node in |
| -- in the tree after which to insert the finalization code. |
| |
| else |
| while not Is_List_Member (Fin_Context) loop |
| Fin_Context := Parent (Fin_Context); |
| end loop; |
| |
| pragma Assert (Present (Fin_Context)); |
| |
| Insert_Action_After (Fin_Context, |
| Make_Implicit_If_Statement (Obj_Decl, |
| Condition => |
| Make_Op_Ne (Loc, |
| Left_Opnd => |
| New_Occurrence_Of (Defining_Entity (Hook_Decl), Loc), |
| Right_Opnd => Make_Null (Loc)), |
| |
| Then_Statements => New_List ( |
| Fin_Call, |
| Hook_Clear))); |
| end if; |
| end Process_Transient_In_Expression; |
| |
| ------------------------ |
| -- Rewrite_Comparison -- |
| ------------------------ |
| |
| procedure Rewrite_Comparison (N : Node_Id) is |
| Typ : constant Entity_Id := Etype (N); |
| |
| False_Result : Boolean; |
| True_Result : Boolean; |
| |
| begin |
| if Nkind (N) = N_Type_Conversion then |
| Rewrite_Comparison (Expression (N)); |
| return; |
| |
| elsif Nkind (N) not in N_Op_Compare then |
| return; |
| end if; |
| |
| -- If both operands are static, then the comparison has been already |
| -- folded in evaluation. |
| |
| pragma Assert |
| (not Is_Static_Expression (Left_Opnd (N)) |
| or else |
| not Is_Static_Expression (Right_Opnd (N))); |
| |
| -- Determine the potential outcome of the comparison assuming that the |
| -- operands are valid and emit a warning when the comparison evaluates |
| -- to True or False only in the presence of invalid values. |
| |
| Warn_On_Constant_Valid_Condition (N); |
| |
| -- Determine the potential outcome of the comparison assuming that the |
| -- operands are not valid. |
| |
| Test_Comparison |
| (Op => N, |
| Assume_Valid => False, |
| True_Result => True_Result, |
| False_Result => False_Result); |
| |
| -- The outcome is a decisive False or True, rewrite the operator into a |
| -- non-static literal. |
| |
| if False_Result or True_Result then |
| Rewrite (N, |
| Convert_To (Typ, |
| New_Occurrence_Of (Boolean_Literals (True_Result), Sloc (N)))); |
| |
| Analyze_And_Resolve (N, Typ); |
| Set_Is_Static_Expression (N, False); |
| Warn_On_Known_Condition (N); |
| end if; |
| end Rewrite_Comparison; |
| |
| ---------------------------- |
| -- Safe_In_Place_Array_Op -- |
| ---------------------------- |
| |
| function Safe_In_Place_Array_Op |
| (Lhs : Node_Id; |
| Op1 : Node_Id; |
| Op2 : Node_Id) return Boolean |
| is |
| Target : Entity_Id; |
| |
| function Is_Safe_Operand (Op : Node_Id) return Boolean; |
| -- Operand is safe if it cannot overlap part of the target of the |
| -- operation. If the operand and the target are identical, the operand |
| -- is safe. The operand can be empty in the case of negation. |
| |
| function Is_Unaliased (N : Node_Id) return Boolean; |
| -- Check that N is a stand-alone entity |
| |
| ------------------ |
| -- Is_Unaliased -- |
| ------------------ |
| |
| function Is_Unaliased (N : Node_Id) return Boolean is |
| begin |
| return |
| Is_Entity_Name (N) |
| and then No (Address_Clause (Entity (N))) |
| and then No (Renamed_Object (Entity (N))); |
| end Is_Unaliased; |
| |
| --------------------- |
| -- Is_Safe_Operand -- |
| --------------------- |
| |
| function Is_Safe_Operand (Op : Node_Id) return Boolean is |
| begin |
| if No (Op) then |
| return True; |
| |
| elsif Is_Entity_Name (Op) then |
| return Is_Unaliased (Op); |
| |
| elsif Nkind (Op) in N_Indexed_Component | N_Selected_Component then |
| return Is_Unaliased (Prefix (Op)); |
| |
| elsif Nkind (Op) = N_Slice then |
| return |
| Is_Unaliased (Prefix (Op)) |
| and then Entity (Prefix (Op)) /= Target; |
| |
| elsif Nkind (Op) = N_Op_Not then |
| return Is_Safe_Operand (Right_Opnd (Op)); |
| |
| else |
| return False; |
| end if; |
| end Is_Safe_Operand; |
| |
| -- Start of processing for Safe_In_Place_Array_Op |
| |
| begin |
| -- Skip this processing if the component size is different from system |
| -- storage unit (since at least for NOT this would cause problems). |
| |
| if Component_Size (Etype (Lhs)) /= System_Storage_Unit then |
| return False; |
| |
| -- Cannot do in place stuff if non-standard Boolean representation |
| |
| elsif Has_Non_Standard_Rep (Component_Type (Etype (Lhs))) then |
| return False; |
| |
| elsif not Is_Unaliased (Lhs) then |
| return False; |
| |
| else |
| Target := Entity (Lhs); |
| return Is_Safe_Operand (Op1) and then Is_Safe_Operand (Op2); |
| end if; |
| end Safe_In_Place_Array_Op; |
| |
| ----------------------- |
| -- Tagged_Membership -- |
| ----------------------- |
| |
| -- There are two different cases to consider depending on whether the right |
| -- operand is a class-wide type or not. If not we just compare the actual |
| -- tag of the left expr to the target type tag: |
| -- |
| -- Left_Expr.Tag = Right_Type'Tag; |
| -- |
| -- If it is a class-wide type we use the RT function CW_Membership which is |
| -- usually implemented by looking in the ancestor tables contained in the |
| -- dispatch table pointed by Left_Expr.Tag for Typ'Tag |
| |
| -- In both cases if Left_Expr is an access type, we first check whether it |
| -- is null. |
| |
| -- Ada 2005 (AI-251): If it is a class-wide interface type we use the RT |
| -- function IW_Membership which is usually implemented by looking in the |
| -- table of abstract interface types plus the ancestor table contained in |
| -- the dispatch table pointed by Left_Expr.Tag for Typ'Tag |
| |
| procedure Tagged_Membership |
| (N : Node_Id; |
| SCIL_Node : out Node_Id; |
| Result : out Node_Id) |
| is |
| Left : constant Node_Id := Left_Opnd (N); |
| Right : constant Node_Id := Right_Opnd (N); |
| Loc : constant Source_Ptr := Sloc (N); |
| |
| -- Handle entities from the limited view |
| |
| Orig_Right_Type : constant Entity_Id := Available_View (Etype (Right)); |
| |
| Full_R_Typ : Entity_Id; |
| Left_Type : Entity_Id := Available_View (Etype (Left)); |
| Right_Type : Entity_Id := Orig_Right_Type; |
| Obj_Tag : Node_Id; |
| |
| begin |
| SCIL_Node := Empty; |
| |
| -- We have to examine the corresponding record type when dealing with |
| -- protected types instead of the original, unexpanded, type. |
| |
| if Ekind (Right_Type) = E_Protected_Type then |
| Right_Type := Corresponding_Record_Type (Right_Type); |
| end if; |
| |
| if Ekind (Left_Type) = E_Protected_Type then |
| Left_Type := Corresponding_Record_Type (Left_Type); |
| end if; |
| |
| -- In the case where the type is an access type, the test is applied |
| -- using the designated types (needed in Ada 2012 for implicit anonymous |
| -- access conversions, for AI05-0149). |
| |
| if Is_Access_Type (Right_Type) then |
| Left_Type := Designated_Type (Left_Type); |
| Right_Type := Designated_Type (Right_Type); |
| end if; |
| |
| if Is_Class_Wide_Type (Left_Type) then |
| Left_Type := Root_Type (Left_Type); |
| end if; |
| |
| if Is_Class_Wide_Type (Right_Type) then |
| Full_R_Typ := Underlying_Type (Root_Type (Right_Type)); |
| else |
| Full_R_Typ := Underlying_Type (Right_Type); |
| end if; |
| |
| Obj_Tag := |
| Make_Selected_Component (Loc, |
| Prefix => Relocate_Node (Left), |
| Selector_Name => |
| New_Occurrence_Of (First_Tag_Component (Left_Type), Loc)); |
| |
| if Is_Class_Wide_Type (Right_Type) then |
| |
| -- No need to issue a run-time check if we statically know that the |
| -- result of this membership test is always true. For example, |
| -- considering the following declarations: |
| |
| -- type Iface is interface; |
| -- type T is tagged null record; |
| -- type DT is new T and Iface with null record; |
| |
| -- Obj1 : T; |
| -- Obj2 : DT; |
| |
| -- These membership tests are always true: |
| |
| -- Obj1 in T'Class |
| -- Obj2 in T'Class; |
| -- Obj2 in Iface'Class; |
| |
| -- We do not need to handle cases where the membership is illegal. |
| -- For example: |
| |
| -- Obj1 in DT'Class; -- Compile time error |
| -- Obj1 in Iface'Class; -- Compile time error |
| |
| if not Is_Interface (Left_Type) |
| and then not Is_Class_Wide_Type (Left_Type) |
| and then (Is_Ancestor (Etype (Right_Type), Left_Type, |
| Use_Full_View => True) |
| or else (Is_Interface (Etype (Right_Type)) |
| and then Interface_Present_In_Ancestor |
| (Typ => Left_Type, |
| Iface => Etype (Right_Type)))) |
| then |
| Result := New_Occurrence_Of (Standard_True, Loc); |
| return; |
| end if; |
| |
| -- Ada 2005 (AI-251): Class-wide applied to interfaces |
| |
| if Is_Interface (Etype (Class_Wide_Type (Right_Type))) |
| |
| -- Support to: "Iface_CW_Typ in Typ'Class" |
| |
| or else Is_Interface (Left_Type) |
| then |
| -- Issue error if IW_Membership operation not available in a |
| -- configurable run-time setting. |
| |
| if not RTE_Available (RE_IW_Membership) then |
| Error_Msg_CRT |
| ("dynamic membership test on interface types", N); |
| Result := Empty; |
| return; |
| end if; |
| |
| Result := |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (RTE (RE_IW_Membership), Loc), |
| Parameter_Associations => New_List ( |
| Make_Attribute_Reference (Loc, |
| Prefix => Obj_Tag, |
| Attribute_Name => Name_Address), |
| New_Occurrence_Of ( |
| Node (First_Elmt (Access_Disp_Table (Full_R_Typ))), |
| Loc))); |
| |
| -- Ada 95: Normal case |
| |
| else |
| -- Issue error if CW_Membership operation not available in a |
| -- configurable run-time setting. |
| |
| if not RTE_Available (RE_CW_Membership) then |
| Error_Msg_CRT |
| ("dynamic membership test on tagged types", N); |
| Result := Empty; |
| return; |
| end if; |
| |
| Result := |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (RTE (RE_CW_Membership), Loc), |
| Parameter_Associations => New_List ( |
| Obj_Tag, |
| New_Occurrence_Of ( |
| Node (First_Elmt (Access_Disp_Table (Full_R_Typ))), |
| Loc))); |
| |
| -- Generate the SCIL node for this class-wide membership test. |
| |
| if Generate_SCIL then |
| SCIL_Node := Make_SCIL_Membership_Test (Sloc (N)); |
| Set_SCIL_Entity (SCIL_Node, Etype (Right_Type)); |
| Set_SCIL_Tag_Value (SCIL_Node, Obj_Tag); |
| end if; |
| end if; |
| |
| -- Right_Type is not a class-wide type |
| |
| else |
| -- No need to check the tag of the object if Right_Typ is abstract |
| |
| if Is_Abstract_Type (Right_Type) then |
| Result := New_Occurrence_Of (Standard_False, Loc); |
| |
| else |
| Result := |
| Make_Op_Eq (Loc, |
| Left_Opnd => Obj_Tag, |
| Right_Opnd => |
| New_Occurrence_Of |
| (Node (First_Elmt (Access_Disp_Table (Full_R_Typ))), Loc)); |
| end if; |
| end if; |
| |
| -- if Left is an access object then generate test of the form: |
| -- * if Right_Type excludes null: Left /= null and then ... |
| -- * if Right_Type includes null: Left = null or else ... |
| |
| if Is_Access_Type (Orig_Right_Type) then |
| if Can_Never_Be_Null (Orig_Right_Type) then |
| Result := Make_And_Then (Loc, |
| Left_Opnd => |
| Make_Op_Ne (Loc, |
| Left_Opnd => Left, |
| Right_Opnd => Make_Null (Loc)), |
| Right_Opnd => Result); |
| |
| else |
| Result := Make_Or_Else (Loc, |
| Left_Opnd => |
| Make_Op_Eq (Loc, |
| Left_Opnd => Left, |
| Right_Opnd => Make_Null (Loc)), |
| Right_Opnd => Result); |
| end if; |
| end if; |
| end Tagged_Membership; |
| |
| ------------------------------ |
| -- Unary_Op_Validity_Checks -- |
| ------------------------------ |
| |
| procedure Unary_Op_Validity_Checks (N : Node_Id) is |
| begin |
| if Validity_Checks_On and Validity_Check_Operands then |
| Ensure_Valid (Right_Opnd (N)); |
| end if; |
| end Unary_Op_Validity_Checks; |
| |
| end Exp_Ch4; |