blob: 8dcfa85e756886cb4c9ceef53cebf44f623011ee [file] [log] [blame]
------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- E X P _ C H 4 --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2021, 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 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
-----------------------
-- 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;
Bodies : List_Id) return Node_Id;
-- Local recursive function used to expand equality for nested composite
-- types. Used by Expand_Record/Array_Equality, 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 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.
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
Prim : Node_Id;
Prim_E : Elmt_Id;
begin
Prim_E := First_Elmt (Collect_Primitive_Operations (Typ));
while Present (Prim_E) loop
Prim := Node (Prim_E);
-- Locate primitive equality with the right signature
if Chars (Prim) = Name_Op_Eq
and then Etype (First_Formal (Prim)) =
Etype (Next_Formal (First_Formal (Prim)))
and then Etype (Prim) = Standard_Boolean
then
if Is_Abstract_Subprogram (Prim) then
return
Make_Raise_Program_Error (Loc,
Reason => PE_Explicit_Raise);
else
return
Make_Function_Call (Loc,
Name => New_Occurrence_Of (Prim, Loc),
Parameter_Associations => New_List (Lhs, Rhs));
end if;
end if;
Next_Elmt (Prim_E);
end loop;
-- 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_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;
else
declare
Ityp : constant Entity_Id := Etype (First_Index (Otyp));
Lo : constant Node_Id := Type_Low_Bound (Ityp);
Hi : constant Node_Id := Type_High_Bound (Ityp);
Lov : Uint;
Hiv : Uint;
begin
if Compile_Time_Known_Value (Lo) then
Lov := Expr_Value (Lo);
else
return False;
end if;
if Compile_Time_Known_Value (Hi) then
Hiv := Expr_Value (Hi);
else
return False;
end if;
return Hiv < Lov + 3;
end;
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;
Num : Int) return Node_Id;
-- This builds the attribute reference Arr'Nam (Expr)
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 : Int;
Index : Node_Id) return Node_Id;
-- This procedure returns the following code
--
-- declare
-- 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;
Num : Int) 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, Num)));
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, Decls);
-- 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 : Int;
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;
Blist : Node_Id;
Atest : Node_Id;
Btest : Node_Id;
begin
Alist := Empty;
Blist := Empty;
for J in 1 .. Number_Dimensions (Ltyp) loop
Atest :=
Make_Op_Eq (Loc,
Left_Opnd => Arr_Attr (A, Name_Length, J),
Right_Opnd => Make_Integer_Literal (Loc, 0));
Btest :=
Make_Op_Eq (Loc,
Left_Opnd => Arr_Attr (B, Name_Length, J),
Right_Opnd => Make_Integer_Literal (Loc, 0));
if No (Alist) then
Alist := Atest;
Blist := Btest;
else
Alist :=
Make_Or_Else (Loc,
Left_Opnd => Relocate_Node (Alist),
Right_Opnd => Atest);
Blist :=
Make_Or_Else (Loc,
Left_Opnd => Relocate_Node (Blist),
Right_Opnd => Btest);
end if;
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;
Rtest : Node_Id;
begin
Result := Empty;
for J in 1 .. Number_Dimensions (Ltyp) loop
Rtest :=
Make_Op_Ne (Loc,
Left_Opnd => Arr_Attr (A, Name_Length, J),
Right_Opnd => Arr_Attr (B, Name_Length, J));
if No (Result) then
Result := Rtest;
else
Result :=
Make_Or_Else (Loc,
Left_Opnd => Relocate_Node (Result),
Right_Opnd => Rtest);
end if;
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 Nkind (First_Idx) = N_Range
and then Compile_Time_Known_Value (Low_Bound (First_Idx))
and then Compile_Time_Known_Value (High_Bound (First_Idx))
and then Expr_Value (High_Bound (First_Idx)) =
Expr_Value (Low_Bound (First_Idx)) + 1
then
declare
Ctyp : constant Entity_Id := Component_Type (Ltyp);
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_Bound (First_Idx))));
R :=
Make_Indexed_Component (Loc,
Prefix => New_Copy_Tree (New_Rhs),
Expressions =>
New_List (New_Copy_Tree (Low_Bound (First_Idx))));
TestL := Expand_Composite_Equality (Nod, Ctyp, L, R, Bodies);
L :=
Make_Indexed_Component (Loc,
Prefix => New_Lhs,
Expressions =>
New_List (New_Copy_Tree (High_Bound (First_Idx))));
R :=
Make_Indexed_Component (Loc,
Prefix => New_Rhs,
Expressions =>
New_List (New_Copy_Tree (High_Bound (First_Idx))));
TestH := Expand_Composite_Equality (Nod, Ctyp, L, R, Bodies);
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;
Bodies : List_Id) return Node_Id
is
Loc : constant Source_Ptr := Sloc (Nod);
Full_Type : Entity_Id;
Eq_Op : Entity_Id;
-- Start of processing for Expand_Composite_Equality
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 array types
if Is_Array_Type (Full_Type) then
-- If the operand is an elementary type other than a floating-point
-- type, then we can simply use the built-in block bitwise equality,
-- since the predefined equality operators always apply and bitwise
-- equality is fine for all these cases.
if Is_Elementary_Type (Component_Type (Full_Type))
and then not Is_Floating_Point_Type (Component_Type (Full_Type))
then
return Make_Op_Eq (Loc, Left_Opnd => Lhs, Right_Opnd => Rhs);
-- For composite component types, and floating-point types, use the
-- expansion. This deals with tagged component types (where we use
-- the applicable equality routine) and floating-point (where we
-- need to worry about negative zeroes), and also the case of any
-- composite type recursively containing such fields.
else
declare
Comp_Typ : Entity_Id;
Hi : Node_Id;
Indx : Node_Id;
Ityp : Entity_Id;
Lo : Node_Id;
begin
-- Do the comparison in the type (or its full view) and not in
-- its unconstrained base type, because the latter operation is
-- more complex and would also require an unchecked conversion.
if Is_Private_Type (Typ) then
Comp_Typ := Underlying_Type (Typ);
else
Comp_Typ := Typ;
end if;
-- Except for the case where the bounds of the type depend on a
-- discriminant, or else we would run into scoping issues.
Indx := First_Index (Comp_Typ);
while Present (Indx) loop
Ityp := Etype (Indx);
Lo := Type_Low_Bound (Ityp);
Hi := Type_High_Bound (Ityp);
if (Nkind (Lo) = N_Identifier
and then Ekind (Entity (Lo)) = E_Discriminant)
or else
(Nkind (Hi) = N_Identifier
and then Ekind (Entity (Hi)) = E_Discriminant)
then
Comp_Typ := Full_Type;
exit;
end if;
Next_Index (Indx);
end loop;
return Expand_Array_Equality (Nod, Lhs, Rhs, Bodies, Comp_Typ);
end;
end if;
-- Case of tagged record types
elsif 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, Bodies);
end if;
-- Non-composite 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.
Concatenation_Error : exception;
-- Raised if concatenation is sure to raise a CE
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 Uint;
-- Set to length of operand. Entries in this array are set only if the
-- corresponding entry in Is_Fixed_Length is True.
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 in 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.
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.
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.
High_Bound : Node_Id := Empty;
-- A tree node representing the high bound of the result (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 : Nat) 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 : Nat) 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;
Subtyp_Ind : Entity_Id;
Ent : Entity_Id;
Len : Uint;
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 (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) then
declare
Index : constant Node_Id := First_Index (Opnd_Typ);
Indx_Typ : constant Entity_Id := Etype (Index);
Lo : constant Node_Id := Type_Low_Bound (Indx_Typ);
Hi : constant Node_Id := Type_High_Bound (Indx_Typ);
begin
-- Fixed length constrained array type with known at compile
-- time bounds is last case of fixed length operand.
if Compile_Time_Known_Value (Lo)
and then
Compile_Time_Known_Value (Hi)
then
declare
Loval : constant Uint := Expr_Value (Lo);
Hival : constant Uint := Expr_Value (Hi);
Len : constant Uint :=
UI_Max (Hival - Loval + 1, Uint_0);
begin
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 :=
Convert_To (Ityp,
Make_Integer_Literal (Loc, Expr_Value (Lo)));
Last_Opnd_High_Bound :=
Convert_To (Ityp,
Make_Integer_Literal (Loc, Expr_Value (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, Expr_Value (Lo)));
Set := True;
end;
end if;
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');
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));
else
Aggr_Length (1) := New_Occurrence_Of (Var_Length (1), Loc);
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)));
-- 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));
else
Clen := New_Occurrence_Of (Var_Length (NN), Loc);
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 safely compute the upper bound, normally
-- Low_Bound + Length - 1.
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 (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, and possibly superfluous warnings will be omitted.
if Istyp /= Standard_Positive
and then not Overflow_Checks_Suppressed (Istyp)
then
Activate_Overflow_Check (High_Bound);
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 (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 (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);
-- 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) then
raise Concatenation_Error;
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));
Result := New_Occurrence_Of (Ent, Loc);
goto Done;
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 (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 a reference to the array object
Result := New_Occurrence_Of (Ent, Loc);
<<Done>>
pragma Assert (Present (Result));
Rewrite (Cnode, Result);
Analyze_And_Resolve (Cnode, Atyp);
exception
when Concatenation_Error =>
-- 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.
Kill_Dead_Code (Declaration_Node (Entity (High_Bound)));
Apply_Compile_Time_Constraint_Error
(N => Cnode,
Msg => "concatenation result upper bound out of range??",
Reason => CE_Range_Check_Failed);
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
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 ???
declare
Idx : Node_Id := First_Index (E);
Len : Node_Id;
Res : Node_Id := Empty;
begin
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;
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 ("??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_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;
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 No (Acts) or else 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);
Actions : List_Id;
Decl : Node_Id;
Expr : Node_Id;
New_If : Node_Id;
New_N : Node_Id;
-- 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.
Force_Expand : constant Boolean := Is_Anonymous_Access_Actual (N);
-- Start of processing for Expand_N_If_Expression
begin
-- 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 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;
-- Make sure Then_Actions and Else_Actions are appropriately moved
-- to the new if statement.
if Present (Then_Actions (N)) then
Insert_List_Before
(First (Then_Statements (New_If)), Then_Actions (N));
end if;
if Present (Else_Actions (N)) then
Insert_List_Before
(First (Else_Statements (New_If)), Else_Actions (N));
end if;
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;
Warn1 : 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.
Warn2 : constant Boolean :=
Warn1
and then Nkind (Original_Node (Rop)) = N_Range
and then Is_Integer_Type (Etype (Lo));
-- For the case where only one bound warning is elided, we also
-- insist on an explicit range and an integer type. The reason is
-- that the use of enumeration ranges including an end point is
-- common, as is the use of a subtype name, one of whose bounds is
-- the same as the type of the expression.
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 Warn1 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 Warn1 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
if Warn2 and then not In_Instance then
Error_Msg_N ("??lower bound test optimized away", Lo);
Error_Msg_N ("\??value is known to be in range", Lo);
end if;
Rewrite (N,
Make_Op_Le (Loc,
Left_Opnd => Lop,
Right_Opnd => High_Bound (Rop)));
Analyze_And_Resolve (N, Restyp);
goto Leave;
-- If upper bound check succeeds and lower bound check is not
-- known to succeed or fail, then replace the range check with
-- a comparison against the lower bound.
elsif Ucheck in Compare_LE then
if Warn2 and then not In_Instance then
Error_Msg_N ("??upper bound test optimized away", Hi);
Error_Msg_N ("\??value is known to be in range", Hi);
end if;
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 Warn1 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);
-- Lower bound check succeeds if value is valid
elsif Warn2 and then Lcheck in Compare_GE then
Error_Msg_N
("?c?lower bound check only fails if it is invalid", Lo);
-- Upper bound check succeeds if value is valid
elsif Warn2 and then Ucheck in Compare_LE then
Error_Msg_N
("?c?upper bound check only fails for invalid values", Hi);
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
R_Op := Make_Predicate_Call (Rtyp, Lop, 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 Is_Equality (Subp : Entity_Id;
Typ : Entity_Id := Empty) return Boolean;
-- Determine whether arbitrary Entity_Id denotes a function with the
-- right name and profile for an equality op, specifically for the
-- base type Typ if Typ is nonempty.
function Find_Equality (Prims : Elist_Id) return Entity_Id;
-- Find a primitive equality function within primitive operation list
-- Prims.
function User_Defined_Primitive_Equality_Op
(Typ : Entity_Id) return Entity_Id;
-- Find a user-defined primitive equality function for a given untagged
-- record type, ignoring visibility. Return Empty if no such op found.
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;
-----------------
-- Is_Equality --
-----------------
function Is_Equality (Subp : Entity_Id;
Typ : Entity_Id := Empty) return Boolean is
Formal_1 : Entity_Id;
Formal_2 : Entity_Id;
begin
-- The equality function carries name "=", returns Boolean, and has
-- exactly two formal parameters of an identical type.
if Ekind (Subp) = E_Function
and then Chars (Subp) = Name_Op_Eq
and then Base_Type (Etype (Subp)) = Standard_Boolean
then
Formal_1 := First_Formal (Subp);
Formal_2 := Empty;
if Present (Formal_1) then
Formal_2 := Next_Formal (Formal_1);
end if;
return
Present (Formal_1)
and then Present (Formal_2)
and then No (Next_Formal (Formal_2))
and then Base_Type (Etype (Formal_1)) =
Base_Type (Etype (Formal_2))
and then
(not Present (Typ)
or else Implementation_Base_Type (Etype (Formal_1)) = Typ);
end if;
return False;
end Is_Equality;
-------------------
-- 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_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;
----------------------------------------
-- User_Defined_Primitive_Equality_Op --
----------------------------------------
function User_Defined_Primitive_Equality_Op
(Typ : Entity_Id) return Entity_Id
is
Enclosing_Scope : constant Entity_Id := Scope (Typ);
E : Entity_Id;
begin
for Private_Entities in Boolean loop
if Private_Entities then
if Ekind (Enclosing_Scope) /= E_Package then
exit;
end if;
E := First_Private_Entity (Enclosing_Scope);
else
E := First_Entity (Enclosing_Scope);
end if;
while Present (E) loop
if Is_Equality (E, Typ) then
return E;
end if;
Next_Entity (E);
end loop;
end loop;
if Is_Derived_Type (Typ) then
return User_Defined_Primitive_Equality_Op
(Implementation_Base_Type (Etype (Typ)));
end if;
return Empty;
end User_Defined_Primitive_Equality_Op;
------------------------------------
-- 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 := A_Typ;
if Ekind (Typl) = E_Private_Type then
Typl := Underlying_Type (Typl);
elsif Ekind (Typl) = E_Private_Subtype then
Typl := Underlying_Type (Base_Type (Typl));
end if;
-- 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;
-- See AI12-0101 (which only removes a legality rule) and then
-- AI05-0123 (which then applies in the previously illegal case).
-- AI12-0101 is a binding interpretation.
elsif Ada_Version >= Ada_2012
and then Present (User_Defined_Primitive_Equality_Op (Typl))
then
Build_Equality_Call (User_Defined_Primitive_Equality_Op (Typl));
-- 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, Bodies));
Insert_Actions (N, Bodies, Suppress => All_Checks);
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),
Bodies));
Insert_Actions (N, Bodies, Suppress => All_Checks);
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
pragma Unreferenced (Hi);
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;
-- 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
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);
Elmt : Elmt_Id;
Disc_O : Entity_Id;
-- Discriminant of the operand type. Its value in the
-- object is captured in a selected component.
Disc_S : Entity_Id;
-- Stored discriminant of the operand. If present, it
-- corresponds to a constrained discriminant of the
-- parent type.
Disc_T : Entity_Id;
-- Discriminant of the target type
begin
Disc_T := First_Discriminant (Target_Type);
Disc_O := First_Discriminant (Operand_Type);
Disc_S := First_Stored_Discriminant (Operand_Type);
if Present (Stored) then
Elmt := First_Elmt (Stored);
else
Elmt := No_Elmt; -- init to avoid warning
end if;
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 (Disc_S) then
Append_To (Cons, New_Copy_Tree (Node (Elmt)));
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_NE ("\<<& [", N, Standard_Program_Error);
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
-- 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)))));
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;
Bodies : List_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;
begin
Comp := C;
loop
-- Exit loop when the next element to be compared is found, or
-- there is no more such element.
exit when No (Comp);
exit when Ekind (Comp) in E_Discriminant | E_Component
and then not (
-- 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.
(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)));
Next_Entity (Comp);
end loop;
return Comp;
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_Entity (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)),
Bodies => Bodies);
-- 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_Entity (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);
if Is_Record_Or_Limited_Type (Etype (Alt)) then
-- We reset the Entity in order to use the primitive equality
-- of the type, as per RM 4.5.2 (28.1/4).
Set_Entity (Cond, Empty);
end if;
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_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);
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
Nop := New_Op_Node (Kind, Sloc (N));
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, Etype (Original_Node (N)), 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;
-- 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;