| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- E X P _ C H 5 -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 1992-2022, Free Software Foundation, Inc. -- |
| -- -- |
| -- GNAT is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 3, or (at your option) any later ver- -- |
| -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- |
| -- for more details. You should have received a copy of the GNU General -- |
| -- Public License distributed with GNAT; see file COPYING3. If not, go to -- |
| -- http://www.gnu.org/licenses for a complete copy of the license. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| with Aspects; use Aspects; |
| with Atree; use Atree; |
| with Checks; use Checks; |
| with Debug; use Debug; |
| with Einfo; use Einfo; |
| with Einfo.Entities; use Einfo.Entities; |
| with Einfo.Utils; use Einfo.Utils; |
| with Elists; use Elists; |
| with Exp_Aggr; use Exp_Aggr; |
| with Exp_Ch6; use Exp_Ch6; |
| with Exp_Ch7; use Exp_Ch7; |
| with Exp_Ch11; use Exp_Ch11; |
| with Exp_Dbug; use Exp_Dbug; |
| with Exp_Pakd; use Exp_Pakd; |
| with Exp_Tss; use Exp_Tss; |
| with Exp_Util; use Exp_Util; |
| with Inline; use Inline; |
| with Namet; use Namet; |
| with Nlists; use Nlists; |
| with Nmake; use Nmake; |
| with Opt; use Opt; |
| with Restrict; use Restrict; |
| with Rident; use Rident; |
| with Rtsfind; use Rtsfind; |
| with Sinfo; use Sinfo; |
| with Sinfo.Nodes; use Sinfo.Nodes; |
| with Sinfo.Utils; use Sinfo.Utils; |
| with Sem; use Sem; |
| with Sem_Aux; use Sem_Aux; |
| with Sem_Ch3; use Sem_Ch3; |
| with Sem_Ch8; use Sem_Ch8; |
| with Sem_Ch13; use Sem_Ch13; |
| with Sem_Eval; use Sem_Eval; |
| with Sem_Res; use Sem_Res; |
| with Sem_Util; use Sem_Util; |
| with Snames; use Snames; |
| with Stand; use Stand; |
| with Stringt; use Stringt; |
| with Tbuild; use Tbuild; |
| with Ttypes; use Ttypes; |
| with Uintp; use Uintp; |
| with Validsw; use Validsw; |
| |
| package body Exp_Ch5 is |
| |
| procedure Build_Formal_Container_Iteration |
| (N : Node_Id; |
| Container : Entity_Id; |
| Cursor : Entity_Id; |
| Init : out Node_Id; |
| Advance : out Node_Id; |
| New_Loop : out Node_Id); |
| -- Utility to create declarations and loop statement for both forms |
| -- of formal container iterators. |
| |
| function Convert_To_Iterable_Type |
| (Container : Entity_Id; |
| Loc : Source_Ptr) return Node_Id; |
| -- Returns New_Occurrence_Of (Container), possibly converted to an ancestor |
| -- type, if the type of Container inherited the Iterable aspect from that |
| -- ancestor. |
| |
| function Change_Of_Representation (N : Node_Id) return Boolean; |
| -- Determine if the right-hand side of assignment N is a type conversion |
| -- which requires a change of representation. Called only for the array |
| -- and record cases. |
| |
| procedure Expand_Assign_Array (N : Node_Id; Rhs : Node_Id); |
| -- N is an assignment which assigns an array value. This routine process |
| -- the various special cases and checks required for such assignments, |
| -- including change of representation. Rhs is normally simply the right- |
| -- hand side of the assignment, except that if the right-hand side is a |
| -- type conversion or a qualified expression, then the RHS is the actual |
| -- expression inside any such type conversions or qualifications. |
| |
| function Expand_Assign_Array_Loop |
| (N : Node_Id; |
| Larray : Entity_Id; |
| Rarray : Entity_Id; |
| L_Type : Entity_Id; |
| R_Type : Entity_Id; |
| Ndim : Pos; |
| Rev : Boolean) return Node_Id; |
| -- N is an assignment statement which assigns an array value. This routine |
| -- expands the assignment into a loop (or nested loops for the case of a |
| -- multi-dimensional array) to do the assignment component by component. |
| -- Larray and Rarray are the entities of the actual arrays on the left-hand |
| -- and right-hand sides. L_Type and R_Type are the types of these arrays |
| -- (which may not be the same, due to either sliding, or to a change of |
| -- representation case). Ndim is the number of dimensions and the parameter |
| -- Rev indicates if the loops run normally (Rev = False), or reversed |
| -- (Rev = True). The value returned is the constructed loop statement. |
| -- Auxiliary declarations are inserted before node N using the standard |
| -- Insert_Actions mechanism. |
| |
| function Expand_Assign_Array_Bitfield |
| (N : Node_Id; |
| Larray : Entity_Id; |
| Rarray : Entity_Id; |
| L_Type : Entity_Id; |
| R_Type : Entity_Id; |
| Rev : Boolean) return Node_Id; |
| -- Alternative to Expand_Assign_Array_Loop for packed bitfields. Generates |
| -- a call to System.Bitfields.Copy_Bitfield, which is more efficient than |
| -- copying component-by-component. |
| |
| function Expand_Assign_Array_Bitfield_Fast |
| (N : Node_Id; |
| Larray : Entity_Id; |
| Rarray : Entity_Id) return Node_Id; |
| -- Alternative to Expand_Assign_Array_Bitfield. Generates a call to |
| -- System.Bitfields.Fast_Copy_Bitfield, which is more efficient than |
| -- Copy_Bitfield, but only works in restricted situations. |
| |
| function Expand_Assign_Array_Loop_Or_Bitfield |
| (N : Node_Id; |
| Larray : Entity_Id; |
| Rarray : Entity_Id; |
| L_Type : Entity_Id; |
| R_Type : Entity_Id; |
| Ndim : Pos; |
| Rev : Boolean) return Node_Id; |
| -- Calls either Expand_Assign_Array_Loop, Expand_Assign_Array_Bitfield, or |
| -- Expand_Assign_Array_Bitfield_Fast as appropriate. |
| |
| procedure Expand_Assign_Record (N : Node_Id); |
| -- N is an assignment of an untagged record value. This routine handles |
| -- the case where the assignment must be made component by component, |
| -- either because the target is not byte aligned, or there is a change |
| -- of representation, or when we have a tagged type with a representation |
| -- clause (this last case is required because holes in the tagged type |
| -- might be filled with components from child types). |
| |
| procedure Expand_Assign_With_Target_Names (N : Node_Id); |
| -- (AI12-0125): N is an assignment statement whose RHS contains occurrences |
| -- of @ that designate the value of the LHS of the assignment. If the LHS |
| -- is side-effect free the target names can be replaced with a copy of the |
| -- LHS; otherwise the semantics of the assignment is described in terms of |
| -- a procedure with an in-out parameter, and expanded as such. |
| |
| procedure Expand_Formal_Container_Loop (N : Node_Id); |
| -- Use the primitives specified in an Iterable aspect to expand a loop |
| -- over a so-called formal container, primarily for SPARK usage. |
| |
| procedure Expand_Formal_Container_Element_Loop (N : Node_Id); |
| -- Same, for an iterator of the form " For E of C". In this case the |
| -- iterator provides the name of the element, and the cursor is generated |
| -- internally. |
| |
| procedure Expand_Iterator_Loop (N : Node_Id); |
| -- Expand loop over arrays and containers that uses the form "for X of C" |
| -- with an optional subtype mark, or "for Y in C". |
| |
| procedure Expand_Iterator_Loop_Over_Container |
| (N : Node_Id; |
| Isc : Node_Id; |
| I_Spec : Node_Id; |
| Container : Node_Id; |
| Container_Typ : Entity_Id); |
| -- Expand loop over containers that uses the form "for X of C" with an |
| -- optional subtype mark, or "for Y in C". Isc is the iteration scheme. |
| -- I_Spec is the iterator specification and Container is either the |
| -- Container (for OF) or the iterator (for IN). |
| |
| procedure Expand_Predicated_Loop (N : Node_Id); |
| -- Expand for loop over predicated subtype |
| |
| function Make_Tag_Ctrl_Assignment (N : Node_Id) return List_Id; |
| -- Generate the necessary code for controlled and tagged assignment, that |
| -- is to say, finalization of the target before, adjustment of the target |
| -- after and save and restore of the tag and finalization pointers which |
| -- are not 'part of the value' and must not be changed upon assignment. N |
| -- is the original Assignment node. |
| |
| -------------------------------------- |
| -- Build_Formal_Container_Iteration -- |
| -------------------------------------- |
| |
| procedure Build_Formal_Container_Iteration |
| (N : Node_Id; |
| Container : Entity_Id; |
| Cursor : Entity_Id; |
| Init : out Node_Id; |
| Advance : out Node_Id; |
| New_Loop : out Node_Id) |
| is |
| Loc : constant Source_Ptr := Sloc (N); |
| Stats : constant List_Id := Statements (N); |
| Typ : constant Entity_Id := Base_Type (Etype (Container)); |
| |
| Has_Element_Op : constant Entity_Id := |
| Get_Iterable_Type_Primitive (Typ, Name_Has_Element); |
| |
| First_Op : Entity_Id; |
| Next_Op : Entity_Id; |
| |
| begin |
| -- Use the proper set of primitives depending on the direction of |
| -- iteration. The legality of a reverse iteration has been checked |
| -- during analysis. |
| |
| if Reverse_Present (Iterator_Specification (Iteration_Scheme (N))) then |
| First_Op := Get_Iterable_Type_Primitive (Typ, Name_Last); |
| Next_Op := Get_Iterable_Type_Primitive (Typ, Name_Previous); |
| |
| else |
| First_Op := Get_Iterable_Type_Primitive (Typ, Name_First); |
| Next_Op := Get_Iterable_Type_Primitive (Typ, Name_Next); |
| end if; |
| |
| -- Declaration for Cursor |
| |
| Init := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Cursor, |
| Object_Definition => New_Occurrence_Of (Etype (First_Op), Loc), |
| Expression => |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (First_Op, Loc), |
| Parameter_Associations => New_List ( |
| Convert_To_Iterable_Type (Container, Loc)))); |
| |
| -- Statement that advances (in the right direction) cursor in loop |
| |
| Advance := |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Cursor, Loc), |
| Expression => |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Next_Op, Loc), |
| Parameter_Associations => New_List ( |
| Convert_To_Iterable_Type (Container, Loc), |
| New_Occurrence_Of (Cursor, Loc)))); |
| |
| -- Iterator is rewritten as a while_loop |
| |
| New_Loop := |
| Make_Loop_Statement (Loc, |
| Iteration_Scheme => |
| Make_Iteration_Scheme (Loc, |
| Condition => |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Has_Element_Op, Loc), |
| Parameter_Associations => New_List ( |
| Convert_To_Iterable_Type (Container, Loc), |
| New_Occurrence_Of (Cursor, Loc)))), |
| Statements => Stats, |
| End_Label => Empty); |
| |
| -- If the contruct has a specified loop name, preserve it in the new |
| -- loop, for possible use in exit statements. |
| |
| if Present (Identifier (N)) |
| and then Comes_From_Source (Identifier (N)) |
| then |
| Set_Identifier (New_Loop, Identifier (N)); |
| end if; |
| end Build_Formal_Container_Iteration; |
| |
| ------------------------------ |
| -- Change_Of_Representation -- |
| ------------------------------ |
| |
| function Change_Of_Representation (N : Node_Id) return Boolean is |
| Rhs : constant Node_Id := Expression (N); |
| begin |
| return |
| Nkind (Rhs) = N_Type_Conversion |
| and then not Has_Compatible_Representation |
| (Target_Type => Etype (Rhs), |
| Operand_Type => Etype (Expression (Rhs))); |
| end Change_Of_Representation; |
| |
| ------------------------------ |
| -- Convert_To_Iterable_Type -- |
| ------------------------------ |
| |
| function Convert_To_Iterable_Type |
| (Container : Entity_Id; |
| Loc : Source_Ptr) return Node_Id |
| is |
| Typ : constant Entity_Id := Base_Type (Etype (Container)); |
| Aspect : constant Node_Id := Find_Aspect (Typ, Aspect_Iterable); |
| Result : Node_Id; |
| |
| begin |
| Result := New_Occurrence_Of (Container, Loc); |
| |
| if Entity (Aspect) /= Typ then |
| Result := |
| Make_Type_Conversion (Loc, |
| Subtype_Mark => New_Occurrence_Of (Entity (Aspect), Loc), |
| Expression => Result); |
| end if; |
| |
| return Result; |
| end Convert_To_Iterable_Type; |
| |
| ------------------------- |
| -- Expand_Assign_Array -- |
| ------------------------- |
| |
| -- There are two issues here. First, do we let Gigi do a block move, or |
| -- do we expand out into a loop? Second, we need to set the two flags |
| -- Forwards_OK and Backwards_OK which show whether the block move (or |
| -- corresponding loops) can be legitimately done in a forwards (low to |
| -- high) or backwards (high to low) manner. |
| |
| procedure Expand_Assign_Array (N : Node_Id; Rhs : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| |
| Lhs : constant Node_Id := Name (N); |
| |
| Act_Lhs : constant Node_Id := Get_Referenced_Object (Lhs); |
| Act_Rhs : Node_Id := Get_Referenced_Object (Rhs); |
| |
| L_Type : constant Entity_Id := |
| Underlying_Type (Get_Actual_Subtype (Act_Lhs)); |
| R_Type : Entity_Id := |
| Underlying_Type (Get_Actual_Subtype (Act_Rhs)); |
| |
| L_Slice : constant Boolean := Nkind (Act_Lhs) = N_Slice; |
| R_Slice : constant Boolean := Nkind (Act_Rhs) = N_Slice; |
| |
| Crep : constant Boolean := Change_Of_Representation (N); |
| |
| pragma Assert |
| (Crep |
| or else Is_Bit_Packed_Array (L_Type) = Is_Bit_Packed_Array (R_Type)); |
| |
| Larray : Node_Id; |
| Rarray : Node_Id; |
| |
| Ndim : constant Pos := Number_Dimensions (L_Type); |
| |
| Loop_Required : Boolean := False; |
| -- This switch is set to True if the array move must be done using |
| -- an explicit front end generated loop. |
| |
| procedure Apply_Dereference (Arg : Node_Id); |
| -- If the argument is an access to an array, and the assignment is |
| -- converted into a procedure call, apply explicit dereference. |
| |
| function Has_Address_Clause (Exp : Node_Id) return Boolean; |
| -- Test if Exp is a reference to an array whose declaration has |
| -- an address clause, or it is a slice of such an array. |
| |
| function Is_Formal_Array (Exp : Node_Id) return Boolean; |
| -- Test if Exp is a reference to an array which is either a formal |
| -- parameter or a slice of a formal parameter. These are the cases |
| -- where hidden aliasing can occur. |
| |
| function Is_Non_Local_Array (Exp : Node_Id) return Boolean; |
| -- Determine if Exp is a reference to an array variable which is other |
| -- than an object defined in the current scope, or a component or a |
| -- slice of such an object. Such objects can be aliased to parameters |
| -- (unlike local array references). |
| |
| ----------------------- |
| -- Apply_Dereference -- |
| ----------------------- |
| |
| procedure Apply_Dereference (Arg : Node_Id) is |
| Typ : constant Entity_Id := Etype (Arg); |
| begin |
| if Is_Access_Type (Typ) then |
| Rewrite (Arg, Make_Explicit_Dereference (Loc, |
| Prefix => Relocate_Node (Arg))); |
| Analyze_And_Resolve (Arg, Designated_Type (Typ)); |
| end if; |
| end Apply_Dereference; |
| |
| ------------------------ |
| -- Has_Address_Clause -- |
| ------------------------ |
| |
| function Has_Address_Clause (Exp : Node_Id) return Boolean is |
| begin |
| return |
| (Is_Entity_Name (Exp) and then |
| Present (Address_Clause (Entity (Exp)))) |
| or else |
| (Nkind (Exp) = N_Slice and then Has_Address_Clause (Prefix (Exp))); |
| end Has_Address_Clause; |
| |
| --------------------- |
| -- Is_Formal_Array -- |
| --------------------- |
| |
| function Is_Formal_Array (Exp : Node_Id) return Boolean is |
| begin |
| return |
| (Is_Entity_Name (Exp) and then Is_Formal (Entity (Exp))) |
| or else |
| (Nkind (Exp) = N_Slice and then Is_Formal_Array (Prefix (Exp))); |
| end Is_Formal_Array; |
| |
| ------------------------ |
| -- Is_Non_Local_Array -- |
| ------------------------ |
| |
| function Is_Non_Local_Array (Exp : Node_Id) return Boolean is |
| begin |
| case Nkind (Exp) is |
| when N_Indexed_Component |
| | N_Selected_Component |
| | N_Slice |
| => |
| return Is_Non_Local_Array (Prefix (Exp)); |
| |
| when others => |
| return |
| not (Is_Entity_Name (Exp) |
| and then Scope (Entity (Exp)) = Current_Scope); |
| end case; |
| end Is_Non_Local_Array; |
| |
| -- Determine if Lhs, Rhs are formal arrays or nonlocal arrays |
| |
| Lhs_Formal : constant Boolean := Is_Formal_Array (Act_Lhs); |
| Rhs_Formal : constant Boolean := Is_Formal_Array (Act_Rhs); |
| |
| Lhs_Non_Local_Var : constant Boolean := Is_Non_Local_Array (Act_Lhs); |
| Rhs_Non_Local_Var : constant Boolean := Is_Non_Local_Array (Act_Rhs); |
| |
| -- Start of processing for Expand_Assign_Array |
| |
| begin |
| -- Deal with length check. Note that the length check is done with |
| -- respect to the right-hand side as given, not a possible underlying |
| -- renamed object, since this would generate incorrect extra checks. |
| |
| Apply_Length_Check_On_Assignment (Rhs, L_Type, Lhs); |
| |
| -- We start by assuming that the move can be done in either direction, |
| -- i.e. that the two sides are completely disjoint. |
| |
| Set_Forwards_OK (N, True); |
| Set_Backwards_OK (N, True); |
| |
| -- Normally it is only the slice case that can lead to overlap, and |
| -- explicit checks for slices are made below. But there is one case |
| -- where the slice can be implicit and invisible to us: when we have a |
| -- one dimensional array, and either both operands are parameters, or |
| -- one is a parameter (which can be a slice passed by reference) and the |
| -- other is a non-local variable. In this case the parameter could be a |
| -- slice that overlaps with the other operand. |
| |
| -- However, if the array subtype is a constrained first subtype in the |
| -- parameter case, then we don't have to worry about overlap, since |
| -- slice assignments aren't possible (other than for a slice denoting |
| -- the whole array). |
| |
| -- Note: No overlap is possible if there is a change of representation, |
| -- so we can exclude this case. |
| |
| if Ndim = 1 |
| and then not Crep |
| and then |
| ((Lhs_Formal and Rhs_Formal) |
| or else |
| (Lhs_Formal and Rhs_Non_Local_Var) |
| or else |
| (Rhs_Formal and Lhs_Non_Local_Var)) |
| and then |
| (not Is_Constrained (Etype (Lhs)) |
| or else not Is_First_Subtype (Etype (Lhs))) |
| then |
| Set_Forwards_OK (N, False); |
| Set_Backwards_OK (N, False); |
| |
| -- Note: the bit-packed case is not worrisome here, since if we have |
| -- a slice passed as a parameter, it is always aligned on a byte |
| -- boundary, and if there are no explicit slices, the assignment |
| -- can be performed directly. |
| end if; |
| |
| -- If either operand has an address clause clear Backwards_OK and |
| -- Forwards_OK, since we cannot tell if the operands overlap. We |
| -- exclude this treatment when Rhs is an aggregate, since we know |
| -- that overlap can't occur. |
| |
| if (Has_Address_Clause (Lhs) and then Nkind (Rhs) /= N_Aggregate) |
| or else Has_Address_Clause (Rhs) |
| then |
| Set_Forwards_OK (N, False); |
| Set_Backwards_OK (N, False); |
| end if; |
| |
| -- We certainly must use a loop for change of representation and also |
| -- we use the operand of the conversion on the right-hand side as the |
| -- effective right-hand side (the component types must match in this |
| -- situation). |
| |
| if Crep then |
| Act_Rhs := Get_Referenced_Object (Rhs); |
| R_Type := Get_Actual_Subtype (Act_Rhs); |
| Loop_Required := True; |
| |
| -- We require a loop if the left side is possibly bit unaligned |
| |
| elsif Possible_Bit_Aligned_Component (Lhs) |
| or else |
| Possible_Bit_Aligned_Component (Rhs) |
| then |
| Loop_Required := True; |
| |
| -- Arrays with controlled components are expanded into a loop to force |
| -- calls to Adjust at the component level. |
| |
| elsif Has_Controlled_Component (L_Type) then |
| Loop_Required := True; |
| |
| -- If object is full access, we cannot tolerate a loop |
| |
| elsif Is_Full_Access_Object (Act_Lhs) |
| or else |
| Is_Full_Access_Object (Act_Rhs) |
| then |
| return; |
| |
| -- Loop is required if we have atomic components since we have to |
| -- be sure to do any accesses on an element by element basis. |
| |
| elsif Has_Atomic_Components (L_Type) |
| or else Has_Atomic_Components (R_Type) |
| or else Is_Full_Access (Component_Type (L_Type)) |
| or else Is_Full_Access (Component_Type (R_Type)) |
| then |
| Loop_Required := True; |
| |
| -- Case where no slice is involved |
| |
| elsif not L_Slice and not R_Slice then |
| |
| -- The following code deals with the case of unconstrained bit packed |
| -- arrays. The problem is that the template for such arrays contains |
| -- the bounds of the actual source level array, but the copy of an |
| -- entire array requires the bounds of the underlying array. It would |
| -- be nice if the back end could take care of this, but right now it |
| -- does not know how, so if we have such a type, then we expand out |
| -- into a loop, which is inefficient but works correctly. If we don't |
| -- do this, we get the wrong length computed for the array to be |
| -- moved. The two cases we need to worry about are: |
| |
| -- Explicit dereference of an unconstrained packed array type as in |
| -- the following example: |
| |
| -- procedure C52 is |
| -- type BITS is array(INTEGER range <>) of BOOLEAN; |
| -- pragma PACK(BITS); |
| -- type A is access BITS; |
| -- P1,P2 : A; |
| -- begin |
| -- P1 := new BITS (1 .. 65_535); |
| -- P2 := new BITS (1 .. 65_535); |
| -- P2.ALL := P1.ALL; |
| -- end C52; |
| |
| -- A formal parameter reference with an unconstrained bit array type |
| -- is the other case we need to worry about (here we assume the same |
| -- BITS type declared above): |
| |
| -- procedure Write_All (File : out BITS; Contents : BITS); |
| -- begin |
| -- File.Storage := Contents; |
| -- end Write_All; |
| |
| -- We expand to a loop in either of these two cases |
| |
| -- Question for future thought. Another potentially more efficient |
| -- approach would be to create the actual subtype, and then do an |
| -- unchecked conversion to this actual subtype ??? |
| |
| Check_Unconstrained_Bit_Packed_Array : declare |
| |
| function Is_UBPA_Reference (Opnd : Node_Id) return Boolean; |
| -- Function to perform required test for the first case, above |
| -- (dereference of an unconstrained bit packed array). |
| |
| ----------------------- |
| -- Is_UBPA_Reference -- |
| ----------------------- |
| |
| function Is_UBPA_Reference (Opnd : Node_Id) return Boolean is |
| Typ : constant Entity_Id := Underlying_Type (Etype (Opnd)); |
| P_Type : Entity_Id; |
| Des_Type : Entity_Id; |
| |
| begin |
| if Present (Packed_Array_Impl_Type (Typ)) |
| and then Is_Array_Type (Packed_Array_Impl_Type (Typ)) |
| and then not Is_Constrained (Packed_Array_Impl_Type (Typ)) |
| then |
| return True; |
| |
| elsif Nkind (Opnd) = N_Explicit_Dereference then |
| P_Type := Underlying_Type (Etype (Prefix (Opnd))); |
| |
| if not Is_Access_Type (P_Type) then |
| return False; |
| |
| else |
| Des_Type := Designated_Type (P_Type); |
| return |
| Is_Bit_Packed_Array (Des_Type) |
| and then not Is_Constrained (Des_Type); |
| end if; |
| |
| else |
| return False; |
| end if; |
| end Is_UBPA_Reference; |
| |
| -- Start of processing for Check_Unconstrained_Bit_Packed_Array |
| |
| begin |
| if Is_UBPA_Reference (Lhs) |
| or else |
| Is_UBPA_Reference (Rhs) |
| then |
| Loop_Required := True; |
| |
| -- Here if we do not have the case of a reference to a bit packed |
| -- unconstrained array case. In this case gigi can most certainly |
| -- handle the assignment if a forwards move is allowed. |
| |
| -- (could it handle the backwards case also???) |
| |
| elsif Forwards_OK (N) then |
| return; |
| end if; |
| end Check_Unconstrained_Bit_Packed_Array; |
| |
| -- The back end can always handle the assignment if the right side is a |
| -- string literal (note that overlap is definitely impossible in this |
| -- case). If the type is packed, a string literal is always converted |
| -- into an aggregate, except in the case of a null slice, for which no |
| -- aggregate can be written. In that case, rewrite the assignment as a |
| -- null statement, a length check has already been emitted to verify |
| -- that the range of the left-hand side is empty. |
| |
| -- Note that this code is not executed if we have an assignment of a |
| -- string literal to a non-bit aligned component of a record, a case |
| -- which cannot be handled by the backend. |
| |
| elsif Nkind (Rhs) = N_String_Literal then |
| if String_Length (Strval (Rhs)) = 0 |
| and then Is_Bit_Packed_Array (L_Type) |
| then |
| Rewrite (N, Make_Null_Statement (Loc)); |
| Analyze (N); |
| end if; |
| |
| return; |
| |
| -- If either operand is bit packed, then we need a loop, since we can't |
| -- be sure that the slice is byte aligned. Similarly, if either operand |
| -- is a possibly unaligned slice, then we need a loop (since the back |
| -- end cannot handle unaligned slices). |
| |
| elsif Is_Bit_Packed_Array (L_Type) |
| or else Is_Bit_Packed_Array (R_Type) |
| or else Is_Possibly_Unaligned_Slice (Lhs) |
| or else Is_Possibly_Unaligned_Slice (Rhs) |
| then |
| Loop_Required := True; |
| |
| -- If we are not bit-packed, and we have only one slice, then no overlap |
| -- is possible except in the parameter case, so we can let the back end |
| -- handle things. |
| |
| elsif not (L_Slice and R_Slice) then |
| if Forwards_OK (N) then |
| return; |
| end if; |
| end if; |
| |
| -- If the right-hand side is a string literal, introduce a temporary for |
| -- it, for use in the generated loop that will follow. |
| |
| if Nkind (Rhs) = N_String_Literal then |
| declare |
| Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Rhs); |
| Decl : Node_Id; |
| |
| begin |
| Decl := |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Temp, |
| Object_Definition => New_Occurrence_Of (L_Type, Loc), |
| Expression => Relocate_Node (Rhs)); |
| |
| Insert_Action (N, Decl); |
| Rewrite (Rhs, New_Occurrence_Of (Temp, Loc)); |
| R_Type := Etype (Temp); |
| end; |
| end if; |
| |
| -- Come here to complete the analysis |
| |
| -- Loop_Required: Set to True if we know that a loop is required |
| -- regardless of overlap considerations. |
| |
| -- Forwards_OK: Set to False if we already know that a forwards |
| -- move is not safe, else set to True. |
| |
| -- Backwards_OK: Set to False if we already know that a backwards |
| -- move is not safe, else set to True |
| |
| -- Our task at this stage is to complete the overlap analysis, which can |
| -- result in possibly setting Forwards_OK or Backwards_OK to False, and |
| -- then generating the final code, either by deciding that it is OK |
| -- after all to let Gigi handle it, or by generating appropriate code |
| -- in the front end. |
| |
| declare |
| L_Index_Typ : constant Entity_Id := Etype (First_Index (L_Type)); |
| R_Index_Typ : constant Entity_Id := Etype (First_Index (R_Type)); |
| |
| Left_Lo : constant Node_Id := Type_Low_Bound (L_Index_Typ); |
| Left_Hi : constant Node_Id := Type_High_Bound (L_Index_Typ); |
| Right_Lo : constant Node_Id := Type_Low_Bound (R_Index_Typ); |
| Right_Hi : constant Node_Id := Type_High_Bound (R_Index_Typ); |
| |
| Act_L_Array : Node_Id; |
| Act_R_Array : Node_Id; |
| |
| Cleft_Lo : Node_Id; |
| Cright_Lo : Node_Id; |
| Condition : Node_Id; |
| |
| Cresult : Compare_Result; |
| |
| begin |
| -- Get the expressions for the arrays. If we are dealing with a |
| -- private type, then convert to the underlying type. We can do |
| -- direct assignments to an array that is a private type, but we |
| -- cannot assign to elements of the array without this extra |
| -- unchecked conversion. |
| |
| -- Note: We propagate Parent to the conversion nodes to generate |
| -- a well-formed subtree. |
| |
| if Nkind (Act_Lhs) = N_Slice then |
| Larray := Prefix (Act_Lhs); |
| else |
| Larray := Act_Lhs; |
| |
| if Is_Private_Type (Etype (Larray)) then |
| declare |
| Par : constant Node_Id := Parent (Larray); |
| begin |
| Larray := |
| Unchecked_Convert_To |
| (Underlying_Type (Etype (Larray)), Larray); |
| Set_Parent (Larray, Par); |
| end; |
| end if; |
| end if; |
| |
| if Nkind (Act_Rhs) = N_Slice then |
| Rarray := Prefix (Act_Rhs); |
| else |
| Rarray := Act_Rhs; |
| |
| if Is_Private_Type (Etype (Rarray)) then |
| declare |
| Par : constant Node_Id := Parent (Rarray); |
| begin |
| Rarray := |
| Unchecked_Convert_To |
| (Underlying_Type (Etype (Rarray)), Rarray); |
| Set_Parent (Rarray, Par); |
| end; |
| end if; |
| end if; |
| |
| -- If both sides are slices, we must figure out whether it is safe |
| -- to do the move in one direction or the other. It is always safe |
| -- if there is a change of representation since obviously two arrays |
| -- with different representations cannot possibly overlap. |
| |
| if (not Crep) and L_Slice and R_Slice then |
| Act_L_Array := Get_Referenced_Object (Prefix (Act_Lhs)); |
| Act_R_Array := Get_Referenced_Object (Prefix (Act_Rhs)); |
| |
| -- If both left- and right-hand arrays are entity names, and refer |
| -- to different entities, then we know that the move is safe (the |
| -- two storage areas are completely disjoint). |
| |
| if Is_Entity_Name (Act_L_Array) |
| and then Is_Entity_Name (Act_R_Array) |
| and then Entity (Act_L_Array) /= Entity (Act_R_Array) |
| then |
| null; |
| |
| -- Otherwise, we assume the worst, which is that the two arrays |
| -- are the same array. There is no need to check if we know that |
| -- is the case, because if we don't know it, we still have to |
| -- assume it. |
| |
| -- Generally if the same array is involved, then we have an |
| -- overlapping case. We will have to really assume the worst (i.e. |
| -- set neither of the OK flags) unless we can determine the lower |
| -- or upper bounds at compile time and compare them. |
| |
| else |
| Cresult := |
| Compile_Time_Compare |
| (Left_Lo, Right_Lo, Assume_Valid => True); |
| |
| if Cresult = Unknown then |
| Cresult := |
| Compile_Time_Compare |
| (Left_Hi, Right_Hi, Assume_Valid => True); |
| end if; |
| |
| case Cresult is |
| when EQ | LE | LT => |
| Set_Backwards_OK (N, False); |
| |
| when GE | GT => |
| Set_Forwards_OK (N, False); |
| |
| when NE | Unknown => |
| Set_Backwards_OK (N, False); |
| Set_Forwards_OK (N, False); |
| end case; |
| end if; |
| end if; |
| |
| -- If after that analysis Loop_Required is False, meaning that we |
| -- have not discovered some non-overlap reason for requiring a loop, |
| -- then the outcome depends on the capabilities of the back end. |
| |
| if not Loop_Required then |
| -- Assume the back end can deal with all cases of overlap by |
| -- falling back to memmove if it cannot use a more efficient |
| -- approach. |
| |
| return; |
| end if; |
| |
| -- At this stage we have to generate an explicit loop, and we have |
| -- the following cases: |
| |
| -- Forwards_OK = True |
| |
| -- Rnn : right_index := right_index'First; |
| -- for Lnn in left-index loop |
| -- left (Lnn) := right (Rnn); |
| -- Rnn := right_index'Succ (Rnn); |
| -- end loop; |
| |
| -- Note: the above code MUST be analyzed with checks off, because |
| -- otherwise the Succ could overflow. But in any case this is more |
| -- efficient. |
| |
| -- Forwards_OK = False, Backwards_OK = True |
| |
| -- Rnn : right_index := right_index'Last; |
| -- for Lnn in reverse left-index loop |
| -- left (Lnn) := right (Rnn); |
| -- Rnn := right_index'Pred (Rnn); |
| -- end loop; |
| |
| -- Note: the above code MUST be analyzed with checks off, because |
| -- otherwise the Pred could overflow. But in any case this is more |
| -- efficient. |
| |
| -- Forwards_OK = Backwards_OK = False |
| |
| -- This only happens if we have the same array on each side. It is |
| -- possible to create situations using overlays that violate this, |
| -- but we simply do not promise to get this "right" in this case. |
| |
| -- There are two possible subcases. If the No_Implicit_Conditionals |
| -- restriction is set, then we generate the following code: |
| |
| -- declare |
| -- T : constant <operand-type> := rhs; |
| -- begin |
| -- lhs := T; |
| -- end; |
| |
| -- If implicit conditionals are permitted, then we generate: |
| |
| -- if Left_Lo <= Right_Lo then |
| -- <code for Forwards_OK = True above> |
| -- else |
| -- <code for Backwards_OK = True above> |
| -- end if; |
| |
| -- In order to detect possible aliasing, we examine the renamed |
| -- expression when the source or target is a renaming. However, |
| -- the renaming may be intended to capture an address that may be |
| -- affected by subsequent code, and therefore we must recover |
| -- the actual entity for the expansion that follows, not the |
| -- object it renames. In particular, if source or target designate |
| -- a portion of a dynamically allocated object, the pointer to it |
| -- may be reassigned but the renaming preserves the proper location. |
| |
| if Is_Entity_Name (Rhs) |
| and then |
| Nkind (Parent (Entity (Rhs))) = N_Object_Renaming_Declaration |
| and then Nkind (Act_Rhs) = N_Slice |
| then |
| Rarray := Rhs; |
| end if; |
| |
| if Is_Entity_Name (Lhs) |
| and then |
| Nkind (Parent (Entity (Lhs))) = N_Object_Renaming_Declaration |
| and then Nkind (Act_Lhs) = N_Slice |
| then |
| Larray := Lhs; |
| end if; |
| |
| -- Cases where either Forwards_OK or Backwards_OK is true |
| |
| if Forwards_OK (N) or else Backwards_OK (N) then |
| if Needs_Finalization (Component_Type (L_Type)) |
| and then Base_Type (L_Type) = Base_Type (R_Type) |
| and then Ndim = 1 |
| and then not No_Ctrl_Actions (N) |
| then |
| declare |
| Proc : constant Entity_Id := |
| TSS (Base_Type (L_Type), TSS_Slice_Assign); |
| Actuals : List_Id; |
| |
| begin |
| Apply_Dereference (Larray); |
| Apply_Dereference (Rarray); |
| Actuals := New_List ( |
| Duplicate_Subexpr (Larray, Name_Req => True), |
| Duplicate_Subexpr (Rarray, Name_Req => True), |
| Duplicate_Subexpr (Left_Lo, Name_Req => True), |
| Duplicate_Subexpr (Left_Hi, Name_Req => True), |
| Duplicate_Subexpr (Right_Lo, Name_Req => True), |
| Duplicate_Subexpr (Right_Hi, Name_Req => True)); |
| |
| Append_To (Actuals, |
| New_Occurrence_Of ( |
| Boolean_Literals (not Forwards_OK (N)), Loc)); |
| |
| Rewrite (N, |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (Proc, Loc), |
| Parameter_Associations => Actuals)); |
| end; |
| |
| else |
| Rewrite (N, |
| Expand_Assign_Array_Loop_Or_Bitfield |
| (N, Larray, Rarray, L_Type, R_Type, Ndim, |
| Rev => not Forwards_OK (N))); |
| end if; |
| |
| -- Case of both are false with No_Implicit_Conditionals |
| |
| elsif Restriction_Active (No_Implicit_Conditionals) then |
| declare |
| T : constant Entity_Id := |
| Make_Defining_Identifier (Loc, Chars => Name_T); |
| |
| begin |
| Rewrite (N, |
| Make_Block_Statement (Loc, |
| Declarations => New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => T, |
| Constant_Present => True, |
| Object_Definition => |
| New_Occurrence_Of (Etype (Rhs), Loc), |
| Expression => Relocate_Node (Rhs))), |
| |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => Relocate_Node (Lhs), |
| Expression => New_Occurrence_Of (T, Loc)))))); |
| end; |
| |
| -- Case of both are false with implicit conditionals allowed |
| |
| else |
| -- Before we generate this code, we must ensure that the left and |
| -- right side array types are defined. They may be itypes, and we |
| -- cannot let them be defined inside the if, since the first use |
| -- in the then may not be executed. |
| |
| Ensure_Defined (L_Type, N); |
| Ensure_Defined (R_Type, N); |
| |
| -- We normally compare addresses to find out which way round to |
| -- do the loop, since this is reliable, and handles the cases of |
| -- parameters, conversions etc. But we can't do that in the bit |
| -- packed case, because addresses don't work there. |
| |
| if not Is_Bit_Packed_Array (L_Type) then |
| Condition := |
| Make_Op_Le (Loc, |
| Left_Opnd => |
| Unchecked_Convert_To (RTE (RE_Integer_Address), |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Make_Indexed_Component (Loc, |
| Prefix => |
| Duplicate_Subexpr_Move_Checks (Larray, True), |
| Expressions => New_List ( |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of |
| (L_Index_Typ, Loc), |
| Attribute_Name => Name_First))), |
| Attribute_Name => Name_Address)), |
| |
| Right_Opnd => |
| Unchecked_Convert_To (RTE (RE_Integer_Address), |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Make_Indexed_Component (Loc, |
| Prefix => |
| Duplicate_Subexpr_Move_Checks (Rarray, True), |
| Expressions => New_List ( |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of |
| (R_Index_Typ, Loc), |
| Attribute_Name => Name_First))), |
| Attribute_Name => Name_Address))); |
| |
| -- For the bit packed and VM cases we use the bounds. That's OK, |
| -- because we don't have to worry about parameters, since they |
| -- cannot cause overlap. Perhaps we should worry about weird slice |
| -- conversions ??? |
| |
| else |
| -- Copy the bounds |
| |
| Cleft_Lo := New_Copy_Tree (Left_Lo); |
| Cright_Lo := New_Copy_Tree (Right_Lo); |
| |
| -- If the types do not match we add an implicit conversion |
| -- here to ensure proper match |
| |
| if Etype (Left_Lo) /= Etype (Right_Lo) then |
| Cright_Lo := |
| Unchecked_Convert_To (Etype (Left_Lo), Cright_Lo); |
| end if; |
| |
| -- Reset the Analyzed flag, because the bounds of the index |
| -- type itself may be universal, and must be reanalyzed to |
| -- acquire the proper type for the back end. |
| |
| Set_Analyzed (Cleft_Lo, False); |
| Set_Analyzed (Cright_Lo, False); |
| |
| Condition := |
| Make_Op_Le (Loc, |
| Left_Opnd => Cleft_Lo, |
| Right_Opnd => Cright_Lo); |
| end if; |
| |
| if Needs_Finalization (Component_Type (L_Type)) |
| and then Base_Type (L_Type) = Base_Type (R_Type) |
| and then Ndim = 1 |
| and then not No_Ctrl_Actions (N) |
| then |
| |
| -- Call TSS procedure for array assignment, passing the |
| -- explicit bounds of right- and left-hand sides. |
| |
| declare |
| Proc : constant Entity_Id := |
| TSS (Base_Type (L_Type), TSS_Slice_Assign); |
| Actuals : List_Id; |
| |
| begin |
| Apply_Dereference (Larray); |
| Apply_Dereference (Rarray); |
| Actuals := New_List ( |
| Duplicate_Subexpr (Larray, Name_Req => True), |
| Duplicate_Subexpr (Rarray, Name_Req => True), |
| Duplicate_Subexpr (Left_Lo, Name_Req => True), |
| Duplicate_Subexpr (Left_Hi, Name_Req => True), |
| Duplicate_Subexpr (Right_Lo, Name_Req => True), |
| Duplicate_Subexpr (Right_Hi, Name_Req => True)); |
| |
| Append_To (Actuals, |
| Make_Op_Not (Loc, |
| Right_Opnd => Condition)); |
| |
| Rewrite (N, |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (Proc, Loc), |
| Parameter_Associations => Actuals)); |
| end; |
| |
| else |
| Rewrite (N, |
| Make_Implicit_If_Statement (N, |
| Condition => Condition, |
| |
| Then_Statements => New_List ( |
| Expand_Assign_Array_Loop_Or_Bitfield |
| (N, Larray, Rarray, L_Type, R_Type, Ndim, |
| Rev => False)), |
| |
| Else_Statements => New_List ( |
| Expand_Assign_Array_Loop_Or_Bitfield |
| (N, Larray, Rarray, L_Type, R_Type, Ndim, |
| Rev => True)))); |
| end if; |
| end if; |
| |
| Analyze (N, Suppress => All_Checks); |
| end; |
| |
| exception |
| when RE_Not_Available => |
| return; |
| end Expand_Assign_Array; |
| |
| ------------------------------ |
| -- Expand_Assign_Array_Loop -- |
| ------------------------------ |
| |
| -- The following is an example of the loop generated for the case of a |
| -- two-dimensional array: |
| |
| -- declare |
| -- R2b : Tm1X1 := 1; |
| -- begin |
| -- for L1b in 1 .. 100 loop |
| -- declare |
| -- R4b : Tm1X2 := 1; |
| -- begin |
| -- for L3b in 1 .. 100 loop |
| -- vm1 (L1b, L3b) := vm2 (R2b, R4b); |
| -- R4b := Tm1X2'succ(R4b); |
| -- end loop; |
| -- end; |
| -- R2b := Tm1X1'succ(R2b); |
| -- end loop; |
| -- end; |
| |
| -- Here Rev is False, and Tm1Xn are the subscript types for the right-hand |
| -- side. The declarations of R2b and R4b are inserted before the original |
| -- assignment statement. |
| |
| function Expand_Assign_Array_Loop |
| (N : Node_Id; |
| Larray : Entity_Id; |
| Rarray : Entity_Id; |
| L_Type : Entity_Id; |
| R_Type : Entity_Id; |
| Ndim : Pos; |
| Rev : Boolean) return Node_Id |
| is |
| Loc : constant Source_Ptr := Sloc (N); |
| |
| Lnn : array (1 .. Ndim) of Entity_Id; |
| Rnn : array (1 .. Ndim) of Entity_Id; |
| -- Entities used as subscripts on left and right sides |
| |
| L_Index_Type : array (1 .. Ndim) of Entity_Id; |
| R_Index_Type : array (1 .. Ndim) of Entity_Id; |
| -- Left and right index types |
| |
| Assign : Node_Id; |
| |
| F_Or_L : Name_Id; |
| S_Or_P : Name_Id; |
| |
| function Build_Step (J : Nat) return Node_Id; |
| -- The increment step for the index of the right-hand side is written |
| -- as an attribute reference (Succ or Pred). This function returns |
| -- the corresponding node, which is placed at the end of the loop body. |
| |
| ---------------- |
| -- Build_Step -- |
| ---------------- |
| |
| function Build_Step (J : Nat) return Node_Id is |
| Step : Node_Id; |
| Lim : Name_Id; |
| |
| begin |
| if Rev then |
| Lim := Name_First; |
| else |
| Lim := Name_Last; |
| end if; |
| |
| Step := |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Rnn (J), Loc), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of (R_Index_Type (J), Loc), |
| Attribute_Name => S_Or_P, |
| Expressions => New_List ( |
| New_Occurrence_Of (Rnn (J), Loc)))); |
| |
| -- Note that on the last iteration of the loop, the index is increased |
| -- (or decreased) past the corresponding bound. This is consistent with |
| -- the C semantics of the back-end, where such an off-by-one value on a |
| -- dead index variable is OK. However, in CodePeer mode this leads to |
| -- spurious warnings, and thus we place a guard around the attribute |
| -- reference. For obvious reasons we only do this for CodePeer. |
| |
| if CodePeer_Mode then |
| Step := |
| Make_If_Statement (Loc, |
| Condition => |
| Make_Op_Ne (Loc, |
| Left_Opnd => New_Occurrence_Of (Lnn (J), Loc), |
| Right_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (L_Index_Type (J), Loc), |
| Attribute_Name => Lim)), |
| Then_Statements => New_List (Step)); |
| end if; |
| |
| return Step; |
| end Build_Step; |
| |
| -- Start of processing for Expand_Assign_Array_Loop |
| |
| begin |
| if Rev then |
| F_Or_L := Name_Last; |
| S_Or_P := Name_Pred; |
| else |
| F_Or_L := Name_First; |
| S_Or_P := Name_Succ; |
| end if; |
| |
| -- Setup index types and subscript entities |
| |
| declare |
| L_Index : Node_Id; |
| R_Index : Node_Id; |
| |
| begin |
| L_Index := First_Index (L_Type); |
| R_Index := First_Index (R_Type); |
| |
| for J in 1 .. Ndim loop |
| Lnn (J) := Make_Temporary (Loc, 'L'); |
| Rnn (J) := Make_Temporary (Loc, 'R'); |
| |
| L_Index_Type (J) := Etype (L_Index); |
| R_Index_Type (J) := Etype (R_Index); |
| |
| Next_Index (L_Index); |
| Next_Index (R_Index); |
| end loop; |
| end; |
| |
| -- Now construct the assignment statement |
| |
| declare |
| ExprL : constant List_Id := New_List; |
| ExprR : constant List_Id := New_List; |
| |
| begin |
| for J in 1 .. Ndim loop |
| Append_To (ExprL, New_Occurrence_Of (Lnn (J), Loc)); |
| Append_To (ExprR, New_Occurrence_Of (Rnn (J), Loc)); |
| end loop; |
| |
| Assign := |
| Make_Assignment_Statement (Loc, |
| Name => |
| Make_Indexed_Component (Loc, |
| Prefix => Duplicate_Subexpr (Larray, Name_Req => True), |
| Expressions => ExprL), |
| Expression => |
| Make_Indexed_Component (Loc, |
| Prefix => Duplicate_Subexpr (Rarray, Name_Req => True), |
| Expressions => ExprR)); |
| |
| -- We set assignment OK, since there are some cases, e.g. in object |
| -- declarations, where we are actually assigning into a constant. |
| -- If there really is an illegality, it was caught long before now, |
| -- and was flagged when the original assignment was analyzed. |
| |
| Set_Assignment_OK (Name (Assign)); |
| |
| -- Propagate the No_Ctrl_Actions flag to individual assignments |
| |
| Set_No_Ctrl_Actions (Assign, No_Ctrl_Actions (N)); |
| end; |
| |
| -- Now construct the loop from the inside out, with the last subscript |
| -- varying most rapidly. Note that Assign is first the raw assignment |
| -- statement, and then subsequently the loop that wraps it up. |
| |
| for J in reverse 1 .. Ndim loop |
| Assign := |
| Make_Block_Statement (Loc, |
| Declarations => New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Rnn (J), |
| Object_Definition => |
| New_Occurrence_Of (R_Index_Type (J), Loc), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (R_Index_Type (J), Loc), |
| Attribute_Name => F_Or_L))), |
| |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List ( |
| Make_Implicit_Loop_Statement (N, |
| Iteration_Scheme => |
| Make_Iteration_Scheme (Loc, |
| Loop_Parameter_Specification => |
| Make_Loop_Parameter_Specification (Loc, |
| Defining_Identifier => Lnn (J), |
| Reverse_Present => Rev, |
| Discrete_Subtype_Definition => |
| New_Occurrence_Of (L_Index_Type (J), Loc))), |
| |
| Statements => New_List (Assign, Build_Step (J)))))); |
| end loop; |
| |
| return Assign; |
| end Expand_Assign_Array_Loop; |
| |
| ---------------------------------- |
| -- Expand_Assign_Array_Bitfield -- |
| ---------------------------------- |
| |
| function Expand_Assign_Array_Bitfield |
| (N : Node_Id; |
| Larray : Entity_Id; |
| Rarray : Entity_Id; |
| L_Type : Entity_Id; |
| R_Type : Entity_Id; |
| Rev : Boolean) return Node_Id |
| is |
| pragma Assert (not Rev); |
| -- Reverse copying is not yet supported by Copy_Bitfield. |
| |
| pragma Assert (not Change_Of_Representation (N)); |
| -- This won't work, for example, to copy a packed array to an unpacked |
| -- array. |
| |
| Loc : constant Source_Ptr := Sloc (N); |
| |
| L_Index_Typ : constant Entity_Id := Etype (First_Index (L_Type)); |
| R_Index_Typ : constant Entity_Id := Etype (First_Index (R_Type)); |
| Left_Lo : constant Node_Id := Type_Low_Bound (L_Index_Typ); |
| Right_Lo : constant Node_Id := Type_Low_Bound (R_Index_Typ); |
| |
| L_Addr : constant Node_Id := |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Make_Indexed_Component (Loc, |
| Prefix => |
| Duplicate_Subexpr (Larray, True), |
| Expressions => New_List (New_Copy_Tree (Left_Lo))), |
| Attribute_Name => Name_Address); |
| |
| L_Bit : constant Node_Id := |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Make_Indexed_Component (Loc, |
| Prefix => |
| Duplicate_Subexpr (Larray, True), |
| Expressions => New_List (New_Copy_Tree (Left_Lo))), |
| Attribute_Name => Name_Bit); |
| |
| R_Addr : constant Node_Id := |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Make_Indexed_Component (Loc, |
| Prefix => |
| Duplicate_Subexpr (Rarray, True), |
| Expressions => New_List (New_Copy_Tree (Right_Lo))), |
| Attribute_Name => Name_Address); |
| |
| R_Bit : constant Node_Id := |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Make_Indexed_Component (Loc, |
| Prefix => |
| Duplicate_Subexpr (Rarray, True), |
| Expressions => New_List (New_Copy_Tree (Right_Lo))), |
| Attribute_Name => Name_Bit); |
| |
| -- Compute the Size of the bitfield |
| |
| -- Note that the length check has already been done, so we can use the |
| -- size of either L or R; they are equal. We can't use 'Size here, |
| -- because sometimes bit fields get copied into a temp, and the 'Size |
| -- ends up being the size of the temp (e.g. an 8-bit temp containing |
| -- a 4-bit bit field). |
| |
| Size : constant Node_Id := |
| Make_Op_Multiply (Loc, |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Duplicate_Subexpr (Name (N), True), |
| Attribute_Name => Name_Length), |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Duplicate_Subexpr (Name (N), True), |
| Attribute_Name => Name_Component_Size)); |
| |
| begin |
| return Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (RTE (RE_Copy_Bitfield), Loc), |
| Parameter_Associations => New_List ( |
| R_Addr, R_Bit, L_Addr, L_Bit, Size)); |
| end Expand_Assign_Array_Bitfield; |
| |
| --------------------------------------- |
| -- Expand_Assign_Array_Bitfield_Fast -- |
| --------------------------------------- |
| |
| function Expand_Assign_Array_Bitfield_Fast |
| (N : Node_Id; |
| Larray : Entity_Id; |
| Rarray : Entity_Id) return Node_Id |
| is |
| pragma Assert (not Change_Of_Representation (N)); |
| -- This won't work, for example, to copy a packed array to an unpacked |
| -- array. |
| |
| -- For L (A .. B) := R (C .. D), we generate: |
| -- |
| -- L := Fast_Copy_Bitfield (R, <offset of R(C)>, L, <offset of L(A)>, |
| -- L (A .. B)'Length * L'Component_Size); |
| -- |
| -- with L and R suitably uncheckedly converted to/from Val_2. |
| -- The offsets are from the start of L and R. |
| |
| Loc : constant Source_Ptr := Sloc (N); |
| |
| L_Typ : constant Entity_Id := Etype (Larray); |
| R_Typ : constant Entity_Id := Etype (Rarray); |
| -- The original type of the arrays |
| |
| L_Val : constant Node_Id := |
| Unchecked_Convert_To (RTE (RE_Val_2), Larray); |
| R_Val : constant Node_Id := |
| Unchecked_Convert_To (RTE (RE_Val_2), Rarray); |
| -- Converted values of left- and right-hand sides |
| |
| L_Small : constant Boolean := |
| Known_Static_RM_Size (L_Typ) |
| and then RM_Size (L_Typ) < Standard_Long_Long_Integer_Size; |
| R_Small : constant Boolean := |
| Known_Static_RM_Size (R_Typ) |
| and then RM_Size (R_Typ) < Standard_Long_Long_Integer_Size; |
| -- Whether the above unchecked conversions need to be padded with zeros |
| |
| C_Size : constant Uint := Component_Size (L_Typ); |
| pragma Assert (C_Size >= 1); |
| pragma Assert (C_Size = Component_Size (R_Typ)); |
| |
| Larray_Bounds : constant Range_Values := |
| Get_Index_Bounds (First_Index (L_Typ)); |
| L_Bounds : constant Range_Values := |
| (if Nkind (Name (N)) = N_Slice |
| then Get_Index_Bounds (Discrete_Range (Name (N))) |
| else Larray_Bounds); |
| -- If the left-hand side is A (First..Last), Larray_Bounds is A'Range, |
| -- and L_Bounds is First..Last. If it's not a slice, we treat it like |
| -- a slice starting at A'First. |
| |
| L_Bit : constant Node_Id := |
| Make_Integer_Literal |
| (Loc, (L_Bounds.First - Larray_Bounds.First) * C_Size); |
| |
| Rarray_Bounds : constant Range_Values := |
| Get_Index_Bounds (First_Index (R_Typ)); |
| R_Bounds : constant Range_Values := |
| (if Nkind (Expression (N)) = N_Slice |
| then Get_Index_Bounds (Discrete_Range (Expression (N))) |
| else Rarray_Bounds); |
| |
| R_Bit : constant Node_Id := |
| Make_Integer_Literal |
| (Loc, (R_Bounds.First - Rarray_Bounds.First) * C_Size); |
| |
| Size : constant Node_Id := |
| Make_Op_Multiply (Loc, |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Duplicate_Subexpr (Name (N), True), |
| Attribute_Name => Name_Length), |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| Duplicate_Subexpr (Larray, True), |
| Attribute_Name => Name_Component_Size)); |
| |
| L_Arg, R_Arg, Call : Node_Id; |
| |
| begin |
| -- The semantics of unchecked conversion between bit-packed arrays that |
| -- are implemented as modular types and modular types is precisely that |
| -- of unchecked conversion between modular types. Therefore, if it needs |
| -- to be padded with zeros, the padding must be moved to the correct end |
| -- for memory order because System.Bitfield_Utils works in memory order. |
| |
| if L_Small |
| and then (Bytes_Big_Endian xor Reverse_Storage_Order (L_Typ)) |
| then |
| L_Arg := Make_Op_Shift_Left (Loc, |
| Left_Opnd => L_Val, |
| Right_Opnd => Make_Integer_Literal (Loc, |
| Standard_Long_Long_Integer_Size - RM_Size (L_Typ))); |
| else |
| L_Arg := L_Val; |
| end if; |
| |
| if R_Small |
| and then (Bytes_Big_Endian xor Reverse_Storage_Order (R_Typ)) |
| then |
| R_Arg := Make_Op_Shift_Left (Loc, |
| Left_Opnd => R_Val, |
| Right_Opnd => Make_Integer_Literal (Loc, |
| Standard_Long_Long_Integer_Size - RM_Size (R_Typ))); |
| else |
| R_Arg := R_Val; |
| end if; |
| |
| Call := Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (RTE (RE_Fast_Copy_Bitfield), Loc), |
| Parameter_Associations => New_List ( |
| R_Arg, R_Bit, L_Arg, L_Bit, Size)); |
| |
| -- Conversely, the final unchecked conversion must take significant bits |
| |
| if L_Small |
| and then (Bytes_Big_Endian xor Reverse_Storage_Order (L_Typ)) |
| then |
| Call := Make_Op_Shift_Right (Loc, |
| Left_Opnd => Call, |
| Right_Opnd => Make_Integer_Literal (Loc, |
| Standard_Long_Long_Integer_Size - RM_Size (L_Typ))); |
| end if; |
| |
| return Make_Assignment_Statement (Loc, |
| Name => Duplicate_Subexpr (Larray, True), |
| Expression => Unchecked_Convert_To (L_Typ, Call)); |
| end Expand_Assign_Array_Bitfield_Fast; |
| |
| ------------------------------------------ |
| -- Expand_Assign_Array_Loop_Or_Bitfield -- |
| ------------------------------------------ |
| |
| function Expand_Assign_Array_Loop_Or_Bitfield |
| (N : Node_Id; |
| Larray : Entity_Id; |
| Rarray : Entity_Id; |
| L_Type : Entity_Id; |
| R_Type : Entity_Id; |
| Ndim : Pos; |
| Rev : Boolean) return Node_Id |
| is |
| |
| L : constant Node_Id := Name (N); |
| R : constant Node_Id := Expression (N); |
| -- Left- and right-hand sides of the assignment statement |
| |
| Slices : constant Boolean := |
| Nkind (L) = N_Slice or else Nkind (R) = N_Slice; |
| L_Prefix_Comp : constant Boolean := |
| -- True if the left-hand side is a slice of a component or slice |
| Nkind (L) = N_Slice |
| and then Nkind (Prefix (L)) in |
| N_Selected_Component | N_Indexed_Component | N_Slice; |
| R_Prefix_Comp : constant Boolean := |
| -- Likewise for the right-hand side |
| Nkind (R) = N_Slice |
| and then Nkind (Prefix (R)) in |
| N_Selected_Component | N_Indexed_Component | N_Slice; |
| |
| begin |
| -- Determine whether Copy_Bitfield or Fast_Copy_Bitfield is appropriate |
| -- (will work, and will be more efficient than component-by-component |
| -- copy). Copy_Bitfield doesn't work for reversed storage orders. It is |
| -- efficient for slices of bit-packed arrays. Copy_Bitfield can read and |
| -- write bits that are not part of the objects being copied, so we don't |
| -- want to use it if there are volatile or independent components. If |
| -- the Prefix of the slice is a component or slice, then it might be a |
| -- part of an object with some other volatile or independent components, |
| -- so we disable the optimization in that case as well. We could |
| -- complicate this code by actually looking for such volatile and |
| -- independent components. |
| |
| if Is_Bit_Packed_Array (L_Type) |
| and then Is_Bit_Packed_Array (R_Type) |
| and then not Reverse_Storage_Order (L_Type) |
| and then not Reverse_Storage_Order (R_Type) |
| and then Ndim = 1 |
| and then Slices |
| and then not Has_Volatile_Component (L_Type) |
| and then not Has_Volatile_Component (R_Type) |
| and then not Has_Independent_Components (L_Type) |
| and then not Has_Independent_Components (R_Type) |
| and then not L_Prefix_Comp |
| and then not R_Prefix_Comp |
| then |
| -- Here if Copy_Bitfield can work (except for the Rev test below). |
| -- Determine whether to call Fast_Copy_Bitfield instead. If we |
| -- are assigning slices, and all the relevant bounds are known at |
| -- compile time, and the maximum object size is no greater than |
| -- System.Bitfields.Val_Bits (i.e. Long_Long_Integer'Size / 2), and |
| -- we don't have enumeration representation clauses, we can use |
| -- Fast_Copy_Bitfield. The max size test is to ensure that the slices |
| -- cannot overlap boundaries not supported by Fast_Copy_Bitfield. |
| |
| pragma Assert (Known_Component_Size (Base_Type (L_Type))); |
| pragma Assert (Known_Component_Size (Base_Type (R_Type))); |
| |
| -- Note that L_Type and R_Type do not necessarily have the same base |
| -- type, because of array type conversions. Hence the need to check |
| -- various properties of both. |
| |
| if Compile_Time_Known_Bounds (Base_Type (L_Type)) |
| and then Compile_Time_Known_Bounds (Base_Type (R_Type)) |
| then |
| declare |
| Left_Base_Index : constant Entity_Id := |
| First_Index (Base_Type (L_Type)); |
| Left_Base_Range : constant Range_Values := |
| Get_Index_Bounds (Left_Base_Index); |
| |
| Right_Base_Index : constant Entity_Id := |
| First_Index (Base_Type (R_Type)); |
| Right_Base_Range : constant Range_Values := |
| Get_Index_Bounds (Right_Base_Index); |
| |
| Known_Left_Slice_Low : constant Boolean := |
| (if Nkind (L) = N_Slice |
| then Compile_Time_Known_Value |
| (Get_Index_Bounds (Discrete_Range (L)).First)); |
| Known_Right_Slice_Low : constant Boolean := |
| (if Nkind (R) = N_Slice |
| then Compile_Time_Known_Value |
| (Get_Index_Bounds (Discrete_Range (R)).Last)); |
| |
| Val_Bits : constant Pos := Standard_Long_Long_Integer_Size / 2; |
| |
| begin |
| if Left_Base_Range.Last - Left_Base_Range.First < Val_Bits |
| and then Right_Base_Range.Last - Right_Base_Range.First < |
| Val_Bits |
| and then Known_Esize (L_Type) |
| and then Known_Esize (R_Type) |
| and then Known_Left_Slice_Low |
| and then Known_Right_Slice_Low |
| and then Compile_Time_Known_Value |
| (Get_Index_Bounds (First_Index (Etype (Larray))).First) |
| and then Compile_Time_Known_Value |
| (Get_Index_Bounds (First_Index (Etype (Rarray))).First) |
| and then |
| not (Is_Enumeration_Type (Etype (Left_Base_Index)) |
| and then Has_Enumeration_Rep_Clause |
| (Etype (Left_Base_Index))) |
| and then RTE_Available (RE_Fast_Copy_Bitfield) |
| then |
| pragma Assert (Known_Esize (L_Type)); |
| pragma Assert (Known_Esize (R_Type)); |
| |
| return Expand_Assign_Array_Bitfield_Fast (N, Larray, Rarray); |
| end if; |
| end; |
| end if; |
| |
| -- Fast_Copy_Bitfield can work if Rev is True, because the data is |
| -- passed and returned by copy. Copy_Bitfield cannot. |
| |
| if not Rev and then RTE_Available (RE_Copy_Bitfield) then |
| return Expand_Assign_Array_Bitfield |
| (N, Larray, Rarray, L_Type, R_Type, Rev); |
| end if; |
| end if; |
| |
| -- Here if we did not return above, with Fast_Copy_Bitfield or |
| -- Copy_Bitfield. |
| |
| return Expand_Assign_Array_Loop |
| (N, Larray, Rarray, L_Type, R_Type, Ndim, Rev); |
| end Expand_Assign_Array_Loop_Or_Bitfield; |
| |
| -------------------------- |
| -- Expand_Assign_Record -- |
| -------------------------- |
| |
| procedure Expand_Assign_Record (N : Node_Id) is |
| Lhs : constant Node_Id := Name (N); |
| Rhs : Node_Id := Expression (N); |
| L_Typ : constant Entity_Id := Base_Type (Etype (Lhs)); |
| |
| begin |
| -- If change of representation, then extract the real right-hand side |
| -- from the type conversion, and proceed with component-wise assignment, |
| -- since the two types are not the same as far as the back end is |
| -- concerned. |
| |
| if Change_Of_Representation (N) then |
| Rhs := Expression (Rhs); |
| |
| -- If this may be a case of a large bit aligned component, then proceed |
| -- with component-wise assignment, to avoid possible clobbering of other |
| -- components sharing bits in the first or last byte of the component to |
| -- be assigned. |
| |
| elsif Possible_Bit_Aligned_Component (Lhs) |
| or else |
| Possible_Bit_Aligned_Component (Rhs) |
| then |
| null; |
| |
| -- If we have a tagged type that has a complete record representation |
| -- clause, we must do we must do component-wise assignments, since child |
| -- types may have used gaps for their components, and we might be |
| -- dealing with a view conversion. |
| |
| elsif Is_Fully_Repped_Tagged_Type (L_Typ) then |
| null; |
| |
| -- If neither condition met, then nothing special to do, the back end |
| -- can handle assignment of the entire component as a single entity. |
| |
| else |
| return; |
| end if; |
| |
| -- At this stage we know that we must do a component wise assignment |
| |
| declare |
| Loc : constant Source_Ptr := Sloc (N); |
| R_Typ : constant Entity_Id := Base_Type (Etype (Rhs)); |
| Decl : constant Node_Id := Declaration_Node (R_Typ); |
| RDef : Node_Id; |
| F : Entity_Id; |
| |
| function Find_Component |
| (Typ : Entity_Id; |
| Comp : Entity_Id) return Entity_Id; |
| -- Find the component with the given name in the underlying record |
| -- declaration for Typ. We need to use the actual entity because the |
| -- type may be private and resolution by identifier alone would fail. |
| |
| function Make_Component_List_Assign |
| (CL : Node_Id; |
| U_U : Boolean := False) return List_Id; |
| -- Returns a sequence of statements to assign the components that |
| -- are referenced in the given component list. The flag U_U is |
| -- used to force the usage of the inferred value of the variant |
| -- part expression as the switch for the generated case statement. |
| |
| function Make_Field_Assign |
| (C : Entity_Id; |
| U_U : Boolean := False) return Node_Id; |
| -- Given C, the entity for a discriminant or component, build an |
| -- assignment for the corresponding field values. The flag U_U |
| -- signals the presence of an Unchecked_Union and forces the usage |
| -- of the inferred discriminant value of C as the right-hand side |
| -- of the assignment. |
| |
| function Make_Field_Assigns (CI : List_Id) return List_Id; |
| -- Given CI, a component items list, construct series of statements |
| -- for fieldwise assignment of the corresponding components. |
| |
| -------------------- |
| -- Find_Component -- |
| -------------------- |
| |
| function Find_Component |
| (Typ : Entity_Id; |
| Comp : Entity_Id) return Entity_Id |
| is |
| Utyp : constant Entity_Id := Underlying_Type (Typ); |
| C : Entity_Id; |
| |
| begin |
| C := First_Entity (Utyp); |
| while Present (C) loop |
| if Chars (C) = Chars (Comp) then |
| return C; |
| |
| -- The component may be a renamed discriminant, in |
| -- which case check against the name of the original |
| -- discriminant of the parent type. |
| |
| elsif Is_Derived_Type (Scope (Comp)) |
| and then Ekind (Comp) = E_Discriminant |
| and then Present (Corresponding_Discriminant (Comp)) |
| and then |
| Chars (C) = Chars (Corresponding_Discriminant (Comp)) |
| then |
| return C; |
| end if; |
| |
| Next_Entity (C); |
| end loop; |
| |
| raise Program_Error; |
| end Find_Component; |
| |
| -------------------------------- |
| -- Make_Component_List_Assign -- |
| -------------------------------- |
| |
| function Make_Component_List_Assign |
| (CL : Node_Id; |
| U_U : Boolean := False) return List_Id |
| is |
| CI : constant List_Id := Component_Items (CL); |
| VP : constant Node_Id := Variant_Part (CL); |
| |
| Constrained_Typ : Entity_Id; |
| Alts : List_Id; |
| DC : Node_Id; |
| DCH : List_Id; |
| Expr : Node_Id; |
| Result : List_Id; |
| V : Node_Id; |
| |
| begin |
| -- Try to find a constrained type to extract discriminant values |
| -- from, so that the case statement built below gets an |
| -- opportunity to be folded by Expand_N_Case_Statement. |
| |
| if U_U or else Is_Constrained (Etype (Rhs)) then |
| Constrained_Typ := Etype (Rhs); |
| elsif Is_Constrained (Etype (Expression (N))) then |
| Constrained_Typ := Etype (Expression (N)); |
| else |
| Constrained_Typ := Empty; |
| end if; |
| |
| Result := Make_Field_Assigns (CI); |
| |
| if Present (VP) then |
| V := First_Non_Pragma (Variants (VP)); |
| Alts := New_List; |
| while Present (V) loop |
| DCH := New_List; |
| DC := First (Discrete_Choices (V)); |
| while Present (DC) loop |
| Append_To (DCH, New_Copy_Tree (DC)); |
| Next (DC); |
| end loop; |
| |
| Append_To (Alts, |
| Make_Case_Statement_Alternative (Loc, |
| Discrete_Choices => DCH, |
| Statements => |
| Make_Component_List_Assign (Component_List (V)))); |
| Next_Non_Pragma (V); |
| end loop; |
| |
| if Present (Constrained_Typ) then |
| Expr := |
| New_Copy (Get_Discriminant_Value ( |
| Entity (Name (VP)), |
| Constrained_Typ, |
| Discriminant_Constraint (Constrained_Typ))); |
| else |
| Expr := |
| Make_Selected_Component (Loc, |
| Prefix => Duplicate_Subexpr (Rhs), |
| Selector_Name => |
| Make_Identifier (Loc, Chars (Name (VP)))); |
| end if; |
| |
| Append_To (Result, |
| Make_Case_Statement (Loc, |
| Expression => Expr, |
| Alternatives => Alts)); |
| end if; |
| |
| return Result; |
| end Make_Component_List_Assign; |
| |
| ----------------------- |
| -- Make_Field_Assign -- |
| ----------------------- |
| |
| function Make_Field_Assign |
| (C : Entity_Id; |
| U_U : Boolean := False) return Node_Id |
| is |
| A : Node_Id; |
| Disc : Entity_Id; |
| Expr : Node_Id; |
| |
| begin |
| -- The discriminant entity to be used in the retrieval below must |
| -- be one in the corresponding type, given that the assignment may |
| -- be between derived and parent types. |
| |
| if Is_Derived_Type (Etype (Rhs)) then |
| Disc := Find_Component (R_Typ, C); |
| else |
| Disc := C; |
| end if; |
| |
| -- In the case of an Unchecked_Union, use the discriminant |
| -- constraint value as on the right-hand side of the assignment. |
| |
| if U_U then |
| Expr := |
| New_Copy (Get_Discriminant_Value (C, |
| Etype (Rhs), |
| Discriminant_Constraint (Etype (Rhs)))); |
| else |
| Expr := |
| Make_Selected_Component (Loc, |
| Prefix => Duplicate_Subexpr (Rhs), |
| Selector_Name => New_Occurrence_Of (Disc, Loc)); |
| end if; |
| |
| -- Generate the assignment statement. When the left-hand side |
| -- is an object with an address clause present, force generated |
| -- temporaries to be renamings so as to correctly assign to any |
| -- overlaid objects. |
| |
| A := |
| Make_Assignment_Statement (Loc, |
| Name => |
| Make_Selected_Component (Loc, |
| Prefix => |
| Duplicate_Subexpr |
| (Exp => Lhs, |
| Name_Req => False, |
| Renaming_Req => |
| Is_Entity_Name (Lhs) |
| and then Present (Address_Clause (Entity (Lhs)))), |
| Selector_Name => |
| New_Occurrence_Of (Find_Component (L_Typ, C), Loc)), |
| Expression => Expr); |
| |
| -- Set Assignment_OK, so discriminants can be assigned |
| |
| Set_Assignment_OK (Name (A), True); |
| |
| if Componentwise_Assignment (N) |
| and then Nkind (Name (A)) = N_Selected_Component |
| and then Chars (Selector_Name (Name (A))) = Name_uParent |
| then |
| Set_Componentwise_Assignment (A); |
| end if; |
| |
| return A; |
| end Make_Field_Assign; |
| |
| ------------------------ |
| -- Make_Field_Assigns -- |
| ------------------------ |
| |
| function Make_Field_Assigns (CI : List_Id) return List_Id is |
| Item : Node_Id; |
| Result : List_Id; |
| |
| begin |
| Item := First (CI); |
| Result := New_List; |
| |
| while Present (Item) loop |
| |
| -- Look for components, but exclude _tag field assignment if |
| -- the special Componentwise_Assignment flag is set. |
| |
| if Nkind (Item) = N_Component_Declaration |
| and then not (Is_Tag (Defining_Identifier (Item)) |
| and then Componentwise_Assignment (N)) |
| then |
| Append_To |
| (Result, Make_Field_Assign (Defining_Identifier (Item))); |
| end if; |
| |
| Next (Item); |
| end loop; |
| |
| return Result; |
| end Make_Field_Assigns; |
| |
| -- Start of processing for Expand_Assign_Record |
| |
| begin |
| -- Note that we need to use the base types for this processing in |
| -- order to retrieve the Type_Definition. In the constrained case, |
| -- we filter out the non relevant fields in |
| -- Make_Component_List_Assign. |
| |
| -- First copy the discriminants. This is done unconditionally. It |
| -- is required in the unconstrained left side case, and also in the |
| -- case where this assignment was constructed during the expansion |
| -- of a type conversion (since initialization of discriminants is |
| -- suppressed in this case). It is unnecessary but harmless in |
| -- other cases. |
| |
| -- Special case: no copy if the target has no discriminants |
| |
| if Has_Discriminants (L_Typ) |
| and then Is_Unchecked_Union (Base_Type (L_Typ)) |
| then |
| null; |
| |
| elsif Has_Discriminants (L_Typ) then |
| F := First_Discriminant (R_Typ); |
| while Present (F) loop |
| |
| -- If we are expanding the initialization of a derived record |
| -- that constrains or renames discriminants of the parent, we |
| -- must use the corresponding discriminant in the parent. |
| |
| declare |
| CF : Entity_Id; |
| |
| begin |
| if Inside_Init_Proc |
| and then Present (Corresponding_Discriminant (F)) |
| then |
| CF := Corresponding_Discriminant (F); |
| else |
| CF := F; |
| end if; |
| |
| if Is_Unchecked_Union (R_Typ) then |
| |
| -- Within an initialization procedure this is the |
| -- assignment to an unchecked union component, in which |
| -- case there is no discriminant to initialize. |
| |
| if Inside_Init_Proc then |
| null; |
| |
| else |
| -- The assignment is part of a conversion from a |
| -- derived unchecked union type with an inferable |
| -- discriminant, to a parent type. |
| |
| Insert_Action (N, Make_Field_Assign (CF, True)); |
| end if; |
| |
| else |
| Insert_Action (N, Make_Field_Assign (CF)); |
| end if; |
| |
| Next_Discriminant (F); |
| end; |
| end loop; |
| |
| -- If the derived type has a stored constraint, assign the value |
| -- of the corresponding discriminants explicitly, skipping those |
| -- that are renamed discriminants. We cannot just retrieve them |
| -- from the Rhs by selected component because they are invisible |
| -- in the type of the right-hand side. |
| |
| if Stored_Constraint (R_Typ) /= No_Elist then |
| declare |
| Assign : Node_Id; |
| Discr_Val : Elmt_Id; |
| |
| begin |
| Discr_Val := First_Elmt (Stored_Constraint (R_Typ)); |
| F := First_Entity (R_Typ); |
| while Present (F) loop |
| if Ekind (F) = E_Discriminant |
| and then Is_Completely_Hidden (F) |
| and then Present (Corresponding_Record_Component (F)) |
| and then |
| (not Is_Entity_Name (Node (Discr_Val)) |
| or else Ekind (Entity (Node (Discr_Val))) /= |
| E_Discriminant) |
| then |
| Assign := |
| Make_Assignment_Statement (Loc, |
| Name => |
| Make_Selected_Component (Loc, |
| Prefix => Duplicate_Subexpr (Lhs), |
| Selector_Name => |
| New_Occurrence_Of |
| (Corresponding_Record_Component (F), Loc)), |
| Expression => New_Copy (Node (Discr_Val))); |
| |
| Set_Assignment_OK (Name (Assign)); |
| Insert_Action (N, Assign); |
| Next_Elmt (Discr_Val); |
| end if; |
| |
| Next_Entity (F); |
| end loop; |
| end; |
| end if; |
| end if; |
| |
| -- We know the underlying type is a record, but its current view |
| -- may be private. We must retrieve the usable record declaration. |
| |
| if Nkind (Decl) in N_Private_Type_Declaration |
| | N_Private_Extension_Declaration |
| and then Present (Full_View (R_Typ)) |
| then |
| RDef := Type_Definition (Declaration_Node (Full_View (R_Typ))); |
| else |
| RDef := Type_Definition (Decl); |
| end if; |
| |
| if Nkind (RDef) = N_Derived_Type_Definition then |
| RDef := Record_Extension_Part (RDef); |
| end if; |
| |
| if Nkind (RDef) = N_Record_Definition |
| and then Present (Component_List (RDef)) |
| then |
| if Is_Unchecked_Union (R_Typ) then |
| Insert_Actions (N, |
| Make_Component_List_Assign (Component_List (RDef), True)); |
| else |
| Insert_Actions (N, |
| Make_Component_List_Assign (Component_List (RDef))); |
| end if; |
| |
| Rewrite (N, Make_Null_Statement (Loc)); |
| end if; |
| end; |
| end Expand_Assign_Record; |
| |
| ------------------------------------- |
| -- Expand_Assign_With_Target_Names -- |
| ------------------------------------- |
| |
| procedure Expand_Assign_With_Target_Names (N : Node_Id) is |
| LHS : constant Node_Id := Name (N); |
| LHS_Typ : constant Entity_Id := Etype (LHS); |
| Loc : constant Source_Ptr := Sloc (N); |
| RHS : constant Node_Id := Expression (N); |
| |
| Ent : Entity_Id; |
| -- The entity of the left-hand side |
| |
| function Replace_Target (N : Node_Id) return Traverse_Result; |
| -- Replace occurrences of the target name by the proper entity: either |
| -- the entity of the LHS in simple cases, or the formal of the |
| -- constructed procedure otherwise. |
| |
| -------------------- |
| -- Replace_Target -- |
| -------------------- |
| |
| function Replace_Target (N : Node_Id) return Traverse_Result is |
| begin |
| if Nkind (N) = N_Target_Name then |
| Rewrite (N, New_Occurrence_Of (Ent, Sloc (N))); |
| |
| -- The expression will be reanalyzed when the enclosing assignment |
| -- is reanalyzed, so reset the entity, which may be a temporary |
| -- created during analysis, e.g. a loop variable for an iterated |
| -- component association. However, if entity is callable then |
| -- resolution has established its proper identity (including in |
| -- rewritten prefixed calls) so we must preserve it. |
| |
| elsif Is_Entity_Name (N) then |
| if Present (Entity (N)) |
| and then not Is_Overloadable (Entity (N)) |
| then |
| Set_Entity (N, Empty); |
| end if; |
| end if; |
| |
| Set_Analyzed (N, False); |
| return OK; |
| end Replace_Target; |
| |
| procedure Replace_Target_Name is new Traverse_Proc (Replace_Target); |
| |
| -- Local variables |
| |
| New_RHS : Node_Id; |
| Proc_Id : Entity_Id; |
| |
| -- Start of processing for Expand_Assign_With_Target_Names |
| |
| begin |
| New_RHS := New_Copy_Tree (RHS); |
| |
| -- The left-hand side is a direct name |
| |
| if Is_Entity_Name (LHS) |
| and then not Is_Renaming_Of_Object (Entity (LHS)) |
| then |
| Ent := Entity (LHS); |
| Replace_Target_Name (New_RHS); |
| |
| -- Generate: |
| -- LHS := ... LHS ...; |
| |
| Rewrite (N, |
| Make_Assignment_Statement (Loc, |
| Name => Relocate_Node (LHS), |
| Expression => New_RHS)); |
| |
| -- The left-hand side is not a direct name, but is side-effect free. |
| -- Capture its value in a temporary to avoid multiple evaluations. |
| |
| elsif Side_Effect_Free (LHS) then |
| Ent := Make_Temporary (Loc, 'T'); |
| Replace_Target_Name (New_RHS); |
| |
| -- Generate: |
| -- T : LHS_Typ := LHS; |
| |
| Insert_Before_And_Analyze (N, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Ent, |
| Object_Definition => New_Occurrence_Of (LHS_Typ, Loc), |
| Expression => New_Copy_Tree (LHS))); |
| |
| -- Generate: |
| -- LHS := ... T ...; |
| |
| Rewrite (N, |
| Make_Assignment_Statement (Loc, |
| Name => Relocate_Node (LHS), |
| Expression => New_RHS)); |
| |
| -- Otherwise wrap the whole assignment statement in a procedure with an |
| -- IN OUT parameter. The original assignment then becomes a call to the |
| -- procedure with the left-hand side as an actual. |
| |
| else |
| Ent := Make_Temporary (Loc, 'T'); |
| Replace_Target_Name (New_RHS); |
| |
| -- Generate: |
| -- procedure P (T : in out LHS_Typ) is |
| -- begin |
| -- T := ... T ...; |
| -- end P; |
| |
| Proc_Id := Make_Temporary (Loc, 'P'); |
| |
| Insert_Before_And_Analyze (N, |
| Make_Subprogram_Body (Loc, |
| Specification => |
| Make_Procedure_Specification (Loc, |
| Defining_Unit_Name => Proc_Id, |
| Parameter_Specifications => New_List ( |
| Make_Parameter_Specification (Loc, |
| Defining_Identifier => Ent, |
| In_Present => True, |
| Out_Present => True, |
| Parameter_Type => |
| New_Occurrence_Of (LHS_Typ, Loc)))), |
| |
| Declarations => Empty_List, |
| |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List ( |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Ent, Loc), |
| Expression => New_RHS))))); |
| |
| -- Generate: |
| -- P (LHS); |
| |
| Rewrite (N, |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (Proc_Id, Loc), |
| Parameter_Associations => New_List (Relocate_Node (LHS)))); |
| end if; |
| |
| -- Analyze rewritten node, either as assignment or procedure call |
| |
| Analyze (N); |
| end Expand_Assign_With_Target_Names; |
| |
| ----------------------------------- |
| -- Expand_N_Assignment_Statement -- |
| ----------------------------------- |
| |
| -- This procedure implements various cases where an assignment statement |
| -- cannot just be passed on to the back end in untransformed state. |
| |
| procedure Expand_N_Assignment_Statement (N : Node_Id) is |
| Crep : constant Boolean := Change_Of_Representation (N); |
| Lhs : constant Node_Id := Name (N); |
| Loc : constant Source_Ptr := Sloc (N); |
| Rhs : constant Node_Id := Expression (N); |
| Typ : constant Entity_Id := Underlying_Type (Etype (Lhs)); |
| Exp : Node_Id; |
| |
| begin |
| -- Special case to check right away, if the Componentwise_Assignment |
| -- flag is set, this is a reanalysis from the expansion of the primitive |
| -- assignment procedure for a tagged type, and all we need to do is to |
| -- expand to assignment of components, because otherwise, we would get |
| -- infinite recursion (since this looks like a tagged assignment which |
| -- would normally try to *call* the primitive assignment procedure). |
| |
| if Componentwise_Assignment (N) then |
| Expand_Assign_Record (N); |
| return; |
| end if; |
| |
| -- Defend against invalid subscripts on left side if we are in standard |
| -- validity checking mode. No need to do this if we are checking all |
| -- subscripts. |
| |
| -- Note that we do this right away, because there are some early return |
| -- paths in this procedure, and this is required on all paths. |
| |
| if Validity_Checks_On |
| and then Validity_Check_Default |
| and then not Validity_Check_Subscripts |
| then |
| Check_Valid_Lvalue_Subscripts (Lhs); |
| end if; |
| |
| -- Separate expansion if RHS contain target names. Note that assignment |
| -- may already have been expanded if RHS is aggregate. |
| |
| if Nkind (N) = N_Assignment_Statement and then Has_Target_Names (N) then |
| Expand_Assign_With_Target_Names (N); |
| return; |
| end if; |
| |
| -- Ada 2005 (AI-327): Handle assignment to priority of protected object |
| |
| -- Rewrite an assignment to X'Priority into a run-time call |
| |
| -- For example: X'Priority := New_Prio_Expr; |
| -- ...is expanded into Set_Ceiling (X._Object, New_Prio_Expr); |
| |
| -- Note that although X'Priority is notionally an object, it is quite |
| -- deliberately not defined as an aliased object in the RM. This means |
| -- that it works fine to rewrite it as a call, without having to worry |
| -- about complications that would other arise from X'Priority'Access, |
| -- which is illegal, because of the lack of aliasing. |
| |
| if Ada_Version >= Ada_2005 then |
| declare |
| Call : Node_Id; |
| Conctyp : Entity_Id; |
| Ent : Entity_Id; |
| Subprg : Entity_Id; |
| RT_Subprg_Name : Node_Id; |
| |
| begin |
| -- Handle chains of renamings |
| |
| Ent := Name (N); |
| while Nkind (Ent) in N_Has_Entity |
| and then Present (Entity (Ent)) |
| and then Is_Object (Entity (Ent)) |
| and then Present (Renamed_Object (Entity (Ent))) |
| loop |
| Ent := Renamed_Object (Entity (Ent)); |
| end loop; |
| |
| -- The attribute Priority applied to protected objects has been |
| -- previously expanded into a call to the Get_Ceiling run-time |
| -- subprogram. In restricted profiles this is not available. |
| |
| if Is_Expanded_Priority_Attribute (Ent) then |
| |
| -- Look for the enclosing concurrent type |
| |
| Conctyp := Current_Scope; |
| while not Is_Concurrent_Type (Conctyp) loop |
| Conctyp := Scope (Conctyp); |
| end loop; |
| |
| pragma Assert (Is_Protected_Type (Conctyp)); |
| |
| -- Generate the first actual of the call |
| |
| Subprg := Current_Scope; |
| while not Present (Protected_Body_Subprogram (Subprg)) loop |
| Subprg := Scope (Subprg); |
| end loop; |
| |
| -- Select the appropriate run-time call |
| |
| if Number_Entries (Conctyp) = 0 then |
| RT_Subprg_Name := |
| New_Occurrence_Of (RTE (RE_Set_Ceiling), Loc); |
| else |
| RT_Subprg_Name := |
| New_Occurrence_Of (RTE (RO_PE_Set_Ceiling), Loc); |
| end if; |
| |
| Call := |
| Make_Procedure_Call_Statement (Loc, |
| Name => RT_Subprg_Name, |
| Parameter_Associations => New_List ( |
| New_Copy_Tree (First (Parameter_Associations (Ent))), |
| Relocate_Node (Expression (N)))); |
| |
| Rewrite (N, Call); |
| Analyze (N); |
| |
| return; |
| end if; |
| end; |
| end if; |
| |
| -- Deal with assignment checks unless suppressed |
| |
| if not Suppress_Assignment_Checks (N) then |
| |
| -- First deal with generation of range check if required, |
| -- and then predicate checks if the type carries a predicate. |
| -- If the Rhs is an expression these tests may have been applied |
| -- already. This is the case if the RHS is a type conversion. |
| -- Other such redundant checks could be removed ??? |
| |
| if Nkind (Rhs) /= N_Type_Conversion |
| or else Entity (Subtype_Mark (Rhs)) /= Typ |
| then |
| if Do_Range_Check (Rhs) then |
| Generate_Range_Check (Rhs, Typ, CE_Range_Check_Failed); |
| end if; |
| |
| Apply_Predicate_Check (Rhs, Typ); |
| end if; |
| end if; |
| |
| -- Check for a special case where a high level transformation is |
| -- required. If we have either of: |
| |
| -- P.field := rhs; |
| -- P (sub) := rhs; |
| |
| -- where P is a reference to a bit packed array, then we have to unwind |
| -- the assignment. The exact meaning of being a reference to a bit |
| -- packed array is as follows: |
| |
| -- An indexed component whose prefix is a bit packed array is a |
| -- reference to a bit packed array. |
| |
| -- An indexed component or selected component whose prefix is a |
| -- reference to a bit packed array is itself a reference ot a |
| -- bit packed array. |
| |
| -- The required transformation is |
| |
| -- Tnn : prefix_type := P; |
| -- Tnn.field := rhs; |
| -- P := Tnn; |
| |
| -- or |
| |
| -- Tnn : prefix_type := P; |
| -- Tnn (subscr) := rhs; |
| -- P := Tnn; |
| |
| -- Since P is going to be evaluated more than once, any subscripts |
| -- in P must have their evaluation forced. |
| |
| if Nkind (Lhs) in N_Indexed_Component | N_Selected_Component |
| and then Is_Ref_To_Bit_Packed_Array (Prefix (Lhs)) |
| then |
| declare |
| BPAR_Expr : constant Node_Id := Relocate_Node (Prefix (Lhs)); |
| BPAR_Typ : constant Entity_Id := Etype (BPAR_Expr); |
| Tnn : constant Entity_Id := |
| Make_Temporary (Loc, 'T', BPAR_Expr); |
| |
| begin |
| -- Insert the post assignment first, because we want to copy the |
| -- BPAR_Expr tree before it gets analyzed in the context of the |
| -- pre assignment. Note that we do not analyze the post assignment |
| -- yet (we cannot till we have completed the analysis of the pre |
| -- assignment). As usual, the analysis of this post assignment |
| -- will happen on its own when we "run into" it after finishing |
| -- the current assignment. |
| |
| Insert_After (N, |
| Make_Assignment_Statement (Loc, |
| Name => New_Copy_Tree (BPAR_Expr), |
| Expression => New_Occurrence_Of (Tnn, Loc))); |
| |
| -- At this stage BPAR_Expr is a reference to a bit packed array |
| -- where the reference was not expanded in the original tree, |
| -- since it was on the left side of an assignment. But in the |
| -- pre-assignment statement (the object definition), BPAR_Expr |
| -- will end up on the right-hand side, and must be reexpanded. To |
| -- achieve this, we reset the analyzed flag of all selected and |
| -- indexed components down to the actual indexed component for |
| -- the packed array. |
| |
| Exp := BPAR_Expr; |
| loop |
| Set_Analyzed (Exp, False); |
| |
| if Nkind (Exp) in N_Indexed_Component | N_Selected_Component |
| then |
| Exp := Prefix (Exp); |
| else |
| exit; |
| end if; |
| end loop; |
| |
| -- Now we can insert and analyze the pre-assignment |
| |
| -- If the right-hand side requires a transient scope, it has |
| -- already been placed on the stack. However, the declaration is |
| -- inserted in the tree outside of this scope, and must reflect |
| -- the proper scope for its variable. This awkward bit is forced |
| -- by the stricter scope discipline imposed by GCC 2.97. |
| |
| declare |
| Uses_Transient_Scope : constant Boolean := |
| Scope_Is_Transient |
| and then N = Node_To_Be_Wrapped; |
| |
| begin |
| if Uses_Transient_Scope then |
| Push_Scope (Scope (Current_Scope)); |
| end if; |
| |
| Insert_Before_And_Analyze (N, |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Tnn, |
| Object_Definition => New_Occurrence_Of (BPAR_Typ, Loc), |
| Expression => BPAR_Expr)); |
| |
| if Uses_Transient_Scope then |
| Pop_Scope; |
| end if; |
| end; |
| |
| -- Now fix up the original assignment and continue processing |
| |
| Rewrite (Prefix (Lhs), |
| New_Occurrence_Of (Tnn, Loc)); |
| |
| -- We do not need to reanalyze that assignment, and we do not need |
| -- to worry about references to the temporary, but we do need to |
| -- make sure that the temporary is not marked as a true constant |
| -- since we now have a generated assignment to it. |
| |
| Set_Is_True_Constant (Tnn, False); |
| end; |
| end if; |
| |
| -- When we have the appropriate type of aggregate in the expression (it |
| -- has been determined during analysis of the aggregate by setting the |
| -- delay flag), let's perform in place assignment and thus avoid |
| -- creating a temporary. |
| |
| if Is_Delayed_Aggregate (Rhs) then |
| Convert_Aggr_In_Assignment (N); |
| Rewrite (N, Make_Null_Statement (Loc)); |
| Analyze (N); |
| |
| return; |
| end if; |
| |
| -- Apply discriminant check if required. If Lhs is an access type to a |
| -- designated type with discriminants, we must always check. If the |
| -- type has unknown discriminants, more elaborate processing below. |
| |
| if Has_Discriminants (Etype (Lhs)) |
| and then not Has_Unknown_Discriminants (Etype (Lhs)) |
| then |
| -- Skip discriminant check if change of representation. Will be |
| -- done when the change of representation is expanded out. |
| |
| if not Crep then |
| Apply_Discriminant_Check (Rhs, Etype (Lhs), Lhs); |
| end if; |
| |
| -- If the type is private without discriminants, and the full type |
| -- has discriminants (necessarily with defaults) a check may still be |
| -- necessary if the Lhs is aliased. The private discriminants must be |
| -- visible to build the discriminant constraints. |
| |
| -- Only an explicit dereference that comes from source indicates |
| -- aliasing. Access to formals of protected operations and entries |
| -- create dereferences but are not semantic aliasings. |
| |
| elsif Is_Private_Type (Etype (Lhs)) |
| and then Has_Discriminants (Typ) |
| and then Nkind (Lhs) = N_Explicit_Dereference |
| and then Comes_From_Source (Lhs) |
| then |
| declare |
| Lt : constant Entity_Id := Etype (Lhs); |
| Ubt : Entity_Id := Base_Type (Typ); |
| |
| begin |
| -- In the case of an expander-generated record subtype whose base |
| -- type still appears private, Typ will have been set to that |
| -- private type rather than the underlying record type (because |
| -- Underlying type will have returned the record subtype), so it's |
| -- necessary to apply Underlying_Type again to the base type to |
| -- get the record type we need for the discriminant check. Such |
| -- subtypes can be created for assignments in certain cases, such |
| -- as within an instantiation passed this kind of private type. |
| -- It would be good to avoid this special test, but making changes |
| -- to prevent this odd form of record subtype seems difficult. ??? |
| |
| if Is_Private_Type (Ubt) then |
| Ubt := Underlying_Type (Ubt); |
| end if; |
| |
| Set_Etype (Lhs, Ubt); |
| Rewrite (Rhs, OK_Convert_To (Base_Type (Ubt), Rhs)); |
| Apply_Discriminant_Check (Rhs, Ubt, Lhs); |
| Set_Etype (Lhs, Lt); |
| end; |
| |
| -- If the Lhs has a private type with unknown discriminants, it may |
| -- have a full view with discriminants, but those are nameable only |
| -- in the underlying type, so convert the Rhs to it before potential |
| -- checking. Convert Lhs as well, otherwise the actual subtype might |
| -- not be constructible. If the discriminants have defaults the type |
| -- is unconstrained and there is nothing to check. |
| -- Ditto if a private type with unknown discriminants has a full view |
| -- that is an unconstrained array, in which case a length check is |
| -- needed. |
| |
| elsif Has_Unknown_Discriminants (Base_Type (Etype (Lhs))) then |
| if Has_Discriminants (Typ) |
| and then not Has_Defaulted_Discriminants (Typ) |
| then |
| Rewrite (Rhs, OK_Convert_To (Base_Type (Typ), Rhs)); |
| Rewrite (Lhs, OK_Convert_To (Base_Type (Typ), Lhs)); |
| Apply_Discriminant_Check (Rhs, Typ, Lhs); |
| |
| elsif Is_Array_Type (Typ) and then Is_Constrained (Typ) then |
| Rewrite (Rhs, OK_Convert_To (Base_Type (Typ), Rhs)); |
| Rewrite (Lhs, OK_Convert_To (Base_Type (Typ), Lhs)); |
| Apply_Length_Check (Rhs, Typ); |
| end if; |
| |
| -- In the access type case, we need the same discriminant check, and |
| -- also range checks if we have an access to constrained array. |
| |
| elsif Is_Access_Type (Etype (Lhs)) |
| and then Is_Constrained (Designated_Type (Etype (Lhs))) |
| then |
| if Has_Discriminants (Designated_Type (Etype (Lhs))) then |
| |
| -- Skip discriminant check if change of representation. Will be |
| -- done when the change of representation is expanded out. |
| |
| if not Crep then |
| Apply_Discriminant_Check (Rhs, Etype (Lhs)); |
| end if; |
| |
| elsif Is_Array_Type (Designated_Type (Etype (Lhs))) then |
| Apply_Range_Check (Rhs, Etype (Lhs)); |
| |
| if Is_Constrained (Etype (Lhs)) then |
| Apply_Length_Check (Rhs, Etype (Lhs)); |
| end if; |
| end if; |
| end if; |
| |
| -- Ada 2005 (AI-231): Generate the run-time check |
| |
| if Is_Access_Type (Typ) |
| and then Can_Never_Be_Null (Etype (Lhs)) |
| and then not Can_Never_Be_Null (Etype (Rhs)) |
| |
| -- If an actual is an out parameter of a null-excluding access |
| -- type, there is access check on entry, so we set the flag |
| -- Suppress_Assignment_Checks on the generated statement to |
| -- assign the actual to the parameter block, and we do not want |
| -- to generate an additional check at this point. |
| |
| and then not Suppress_Assignment_Checks (N) |
| then |
| Apply_Constraint_Check (Rhs, Etype (Lhs)); |
| end if; |
| |
| -- Ada 2012 (AI05-148): Update current accessibility level if Rhs is a |
| -- stand-alone obj of an anonymous access type. Do not install the check |
| -- when the Lhs denotes a container cursor and the Next function employs |
| -- an access type, because this can never result in a dangling pointer. |
| |
| if Is_Access_Type (Typ) |
| and then Is_Entity_Name (Lhs) |
| and then Ekind (Entity (Lhs)) /= E_Loop_Parameter |
| and then Present (Effective_Extra_Accessibility (Entity (Lhs))) |
| then |
| declare |
| function Lhs_Entity return Entity_Id; |
| -- Look through renames to find the underlying entity. |
| -- For assignment to a rename, we don't care about the |
| -- Enclosing_Dynamic_Scope of the rename declaration. |
| |
| ---------------- |
| -- Lhs_Entity -- |
| ---------------- |
| |
| function Lhs_Entity return Entity_Id is |
| Result : Entity_Id := Entity (Lhs); |
| |
| begin |
| while Present (Renamed_Object (Result)) loop |
| |
| -- Renamed_Object must return an Entity_Name here |
| -- because of preceding "Present (E_E_A (...))" test. |
| |
| Result := Entity (Renamed_Object (Result)); |
| end loop; |
| |
| return Result; |
| end Lhs_Entity; |
| |
| -- Local Declarations |
| |
| Access_Check : constant Node_Id := |
| Make_Raise_Program_Error (Loc, |
| Condition => |
| Make_Op_Gt (Loc, |
| Left_Opnd => |
| Accessibility_Level (Rhs, Dynamic_Level), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, |
| Intval => |
| Scope_Depth |
| (Enclosing_Dynamic_Scope |
| (Lhs_Entity)))), |
| Reason => PE_Accessibility_Check_Failed); |
| |
| Access_Level_Update : constant Node_Id := |
| Make_Assignment_Statement (Loc, |
| Name => |
| New_Occurrence_Of |
| (Effective_Extra_Accessibility |
| (Entity (Lhs)), Loc), |
| Expression => |
| Accessibility_Level |
| (Expr => Rhs, |
| Level => Dynamic_Level, |
| Allow_Alt_Model => False)); |
| |
| begin |
| if not Accessibility_Checks_Suppressed (Entity (Lhs)) then |
| Insert_Action (N, Access_Check); |
| end if; |
| |
| Insert_Action (N, Access_Level_Update); |
| end; |
| end if; |
| |
| -- Case of assignment to a bit packed array element. If there is a |
| -- change of representation this must be expanded into components, |
| -- otherwise this is a bit-field assignment. |
| |
| if Nkind (Lhs) = N_Indexed_Component |
| and then Is_Bit_Packed_Array (Etype (Prefix (Lhs))) |
| then |
| -- Normal case, no change of representation |
| |
| if not Crep then |
| Expand_Bit_Packed_Element_Set (N); |
| return; |
| |
| -- Change of representation case |
| |
| else |
| -- Generate the following, to force component-by-component |
| -- assignments in an efficient way. Otherwise each component |
| -- will require a temporary and two bit-field manipulations. |
| |
| -- T1 : Elmt_Type; |
| -- T1 := RhS; |
| -- Lhs := T1; |
| |
| declare |
| Tnn : constant Entity_Id := Make_Temporary (Loc, 'T'); |
| Stats : List_Id; |
| |
| begin |
| Stats := |
| New_List ( |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Tnn, |
| Object_Definition => |
| New_Occurrence_Of (Etype (Lhs), Loc)), |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Tnn, Loc), |
| Expression => Relocate_Node (Rhs)), |
| Make_Assignment_Statement (Loc, |
| Name => Relocate_Node (Lhs), |
| Expression => New_Occurrence_Of (Tnn, Loc))); |
| |
| Insert_Actions (N, Stats); |
| Rewrite (N, Make_Null_Statement (Loc)); |
| Analyze (N); |
| end; |
| end if; |
| |
| -- Build-in-place function call case. This is for assignment statements |
| -- that come from aggregate component associations or from init procs. |
| -- User-written assignment statements with b-i-p calls are handled |
| -- elsewhere. |
| |
| elsif Is_Build_In_Place_Function_Call (Rhs) then |
| pragma Assert (not Comes_From_Source (N)); |
| Make_Build_In_Place_Call_In_Assignment (N, Rhs); |
| |
| elsif Is_Tagged_Type (Typ) |
| or else (Needs_Finalization (Typ) and then not Is_Array_Type (Typ)) |
| then |
| Tagged_Case : declare |
| L : List_Id := No_List; |
| Expand_Ctrl_Actions : constant Boolean := not No_Ctrl_Actions (N); |
| |
| begin |
| -- In the controlled case, we ensure that function calls are |
| -- evaluated before finalizing the target. In all cases, it makes |
| -- the expansion easier if the side effects are removed first. |
| |
| Remove_Side_Effects (Lhs); |
| Remove_Side_Effects (Rhs); |
| |
| -- Avoid recursion in the mechanism |
| |
| Set_Analyzed (N); |
| |
| -- If dispatching assignment, we need to dispatch to _assign |
| |
| if Is_Class_Wide_Type (Typ) |
| |
| -- If the type is tagged, we may as well use the predefined |
| -- primitive assignment. This avoids inlining a lot of code |
| -- and in the class-wide case, the assignment is replaced |
| -- by a dispatching call to _assign. It is suppressed in the |
| -- case of assignments created by the expander that correspond |
| -- to initializations, where we do want to copy the tag |
| -- (Expand_Ctrl_Actions flag is set False in this case). It is |
| -- also suppressed if restriction No_Dispatching_Calls is in |
| -- force because in that case predefined primitives are not |
| -- generated. |
| |
| or else (Is_Tagged_Type (Typ) |
| and then Chars (Current_Scope) /= Name_uAssign |
| and then Expand_Ctrl_Actions |
| and then |
| not Restriction_Active (No_Dispatching_Calls)) |
| then |
| -- We should normally not encounter any limited type here, |
| -- except in the corner case where an assignment was not |
| -- intended like the pathological case of a raise expression |
| -- within a return statement. |
| |
| if Is_Limited_Type (Typ) then |
| pragma Assert (not Comes_From_Source (N)); |
| return; |
| end if; |
| |
| -- Fetch the primitive op _assign and proper type to call it. |
| -- Because of possible conflicts between private and full view, |
| -- fetch the proper type directly from the operation profile. |
| |
| declare |
| Op : constant Entity_Id := |
| Find_Prim_Op (Typ, Name_uAssign); |
| F_Typ : Entity_Id := Etype (First_Formal (Op)); |
| |
| begin |
| -- If the assignment is dispatching, make sure to use the |
| -- proper type. |
| |
| if Is_Class_Wide_Type (Typ) then |
| F_Typ := Class_Wide_Type (F_Typ); |
| end if; |
| |
| L := New_List; |
| |
| -- In case of assignment to a class-wide tagged type, before |
| -- the assignment we generate run-time check to ensure that |
| -- the tags of source and target match. |
| |
| if not Tag_Checks_Suppressed (Typ) |
| and then Is_Class_Wide_Type (Typ) |
| and then Is_Tagged_Type (Typ) |
| and then Is_Tagged_Type (Underlying_Type (Etype (Rhs))) |
| then |
| declare |
| Lhs_Tag : Node_Id; |
| Rhs_Tag : Node_Id; |
| |
| begin |
| if not Is_Interface (Typ) then |
| Lhs_Tag := |
| Make_Selected_Component (Loc, |
| Prefix => Duplicate_Subexpr (Lhs), |
| Selector_Name => |
| Make_Identifier (Loc, Name_uTag)); |
| Rhs_Tag := |
| Make_Selected_Component (Loc, |
| Prefix => Duplicate_Subexpr (Rhs), |
| Selector_Name => |
| Make_Identifier (Loc, Name_uTag)); |
| else |
| -- Displace the pointer to the base of the objects |
| -- applying 'Address, which is later expanded into |
| -- a call to RE_Base_Address. |
| |
| Lhs_Tag := |
| Make_Explicit_Dereference (Loc, |
| Prefix => |
| Unchecked_Convert_To (RTE (RE_Tag_Ptr), |
| Make_Attribute_Reference (Loc, |
| Prefix => Duplicate_Subexpr (Lhs), |
| Attribute_Name => Name_Address))); |
| Rhs_Tag := |
| Make_Explicit_Dereference (Loc, |
| Prefix => |
| Unchecked_Convert_To (RTE (RE_Tag_Ptr), |
| Make_Attribute_Reference (Loc, |
| Prefix => Duplicate_Subexpr (Rhs), |
| Attribute_Name => Name_Address))); |
| end if; |
| |
| Append_To (L, |
| Make_Raise_Constraint_Error (Loc, |
| Condition => |
| Make_Op_Ne (Loc, |
| Left_Opnd => Lhs_Tag, |
| Right_Opnd => Rhs_Tag), |
| Reason => CE_Tag_Check_Failed)); |
| end; |
| end if; |
| |
| declare |
| Left_N : Node_Id := Duplicate_Subexpr (Lhs); |
| Right_N : Node_Id := Duplicate_Subexpr (Rhs); |
| |
| begin |
| -- In order to dispatch the call to _assign the type of |
| -- the actuals must match. Add conversion (if required). |
| |
| if Etype (Lhs) /= F_Typ then |
| Left_N := Unchecked_Convert_To (F_Typ, Left_N); |
| end if; |
| |
| if Etype (Rhs) /= F_Typ then |
| Right_N := Unchecked_Convert_To (F_Typ, Right_N); |
| end if; |
| |
| Append_To (L, |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (Op, Loc), |
| Parameter_Associations => New_List ( |
| Node1 => Left_N, |
| Node2 => Right_N))); |
| end; |
| end; |
| |
| else |
| L := Make_Tag_Ctrl_Assignment (N); |
| |
| -- We can't afford to have destructive Finalization Actions in |
| -- the Self assignment case, so if the target and the source |
| -- are not obviously different, code is generated to avoid the |
| -- self assignment case: |
| |
| -- if lhs'address /= rhs'address then |
| -- <code for controlled and/or tagged assignment> |
| -- end if; |
| |
| -- Skip this if Restriction (No_Finalization) is active |
| |
| if not Statically_Different (Lhs, Rhs) |
| and then Expand_Ctrl_Actions |
| and then not Restriction_Active (No_Finalization) |
| then |
| L := New_List ( |
| Make_Implicit_If_Statement (N, |
| Condition => |
| Make_Op_Ne (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => Duplicate_Subexpr (Lhs), |
| Attribute_Name => Name_Address), |
| |
| Right_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => Duplicate_Subexpr (Rhs), |
| Attribute_Name => Name_Address)), |
| |
| Then_Statements => L)); |
| end if; |
| |
| -- We need to set up an exception handler for implementing |
| -- 7.6.1(18). The remaining adjustments are tackled by the |
| -- implementation of adjust for record_controllers (see |
| -- s-finimp.adb). |
| |
| -- This is skipped if we have no finalization |
| |
| if Expand_Ctrl_Actions |
| and then not Restriction_Active (No_Finalization) |
| then |
| L := New_List ( |
| Make_Block_Statement (Loc, |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => L, |
| Exception_Handlers => New_List ( |
| Make_Handler_For_Ctrl_Operation (Loc))))); |
| end if; |
| end if; |
| |
| Rewrite (N, |
| Make_Block_Statement (Loc, |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, Statements => L))); |
| |
| -- If no restrictions on aborts, protect the whole assignment |
| -- for controlled objects as per 9.8(11). |
| |
| if Needs_Finalization (Typ) |
| and then Expand_Ctrl_Actions |
| and then Abort_Allowed |
| then |
| declare |
| Blk : constant Entity_Id := |
| New_Internal_Entity |
| (E_Block, Current_Scope, Sloc (N), 'B'); |
| AUD : constant Entity_Id := RTE (RE_Abort_Undefer_Direct); |
| |
| begin |
| Set_Is_Abort_Block (N); |
| |
| Set_Scope (Blk, Current_Scope); |
| Set_Etype (Blk, Standard_Void_Type); |
| Set_Identifier (N, New_Occurrence_Of (Blk, Sloc (N))); |
| |
| Prepend_To (L, Build_Runtime_Call (Loc, RE_Abort_Defer)); |
| Set_At_End_Proc (Handled_Statement_Sequence (N), |
| New_Occurrence_Of (AUD, Loc)); |
| |
| -- Present the Abort_Undefer_Direct function to the backend |
| -- so that it can inline the call to the function. |
| |
| Add_Inlined_Body (AUD, N); |
| |
| Expand_At_End_Handler |
| (Handled_Statement_Sequence (N), Blk); |
| end; |
| end if; |
| |
| -- N has been rewritten to a block statement for which it is |
| -- known by construction that no checks are necessary: analyze |
| -- it with all checks suppressed. |
| |
| Analyze (N, Suppress => All_Checks); |
| return; |
| end Tagged_Case; |
| |
| -- Array types |
| |
| elsif Is_Array_Type (Typ) then |
| declare |
| Actual_Rhs : Node_Id := Rhs; |
| |
| begin |
| while Nkind (Actual_Rhs) in |
| N_Type_Conversion | N_Qualified_Expression |
| loop |
| Actual_Rhs := Expression (Actual_Rhs); |
| end loop; |
| |
| Expand_Assign_Array (N, Actual_Rhs); |
| return; |
| end; |
| |
| -- Record types |
| |
| elsif Is_Record_Type (Typ) then |
| Expand_Assign_Record (N); |
| return; |
| |
| -- Scalar types. This is where we perform the processing related to the |
| -- requirements of (RM 13.9.1(9-11)) concerning the handling of invalid |
| -- scalar values. |
| |
| elsif Is_Scalar_Type (Typ) then |
| |
| -- Case where right side is known valid |
| |
| if Expr_Known_Valid (Rhs) then |
| |
| -- Here the right side is valid, so it is fine. The case to deal |
| -- with is when the left side is a local variable reference whose |
| -- value is not currently known to be valid. If this is the case, |
| -- and the assignment appears in an unconditional context, then |
| -- we can mark the left side as now being valid if one of these |
| -- conditions holds: |
| |
| -- The expression of the right side has Do_Range_Check set so |
| -- that we know a range check will be performed. Note that it |
| -- can be the case that a range check is omitted because we |
| -- make the assumption that we can assume validity for operands |
| -- appearing in the right side in determining whether a range |
| -- check is required |
| |
| -- The subtype of the right side matches the subtype of the |
| -- left side. In this case, even though we have not checked |
| -- the range of the right side, we know it is in range of its |
| -- subtype if the expression is valid. |
| |
| if Is_Local_Variable_Reference (Lhs) |
| and then not Is_Known_Valid (Entity (Lhs)) |
| and then In_Unconditional_Context (N) |
| then |
| if Do_Range_Check (Rhs) |
| or else Etype (Lhs) = Etype (Rhs) |
| then |
| Set_Is_Known_Valid (Entity (Lhs), True); |
| end if; |
| end if; |
| |
| -- Case where right side may be invalid in the sense of the RM |
| -- reference above. The RM does not require that we check for the |
| -- validity on an assignment, but it does require that the assignment |
| -- of an invalid value not cause erroneous behavior. |
| |
| -- The general approach in GNAT is to use the Is_Known_Valid flag |
| -- to avoid the need for validity checking on assignments. However |
| -- in some cases, we have to do validity checking in order to make |
| -- sure that the setting of this flag is correct. |
| |
| else |
| -- Validate right side if we are validating copies |
| |
| if Validity_Checks_On |
| and then Validity_Check_Copies |
| then |
| -- Skip this if left-hand side is an array or record component |
| -- and elementary component validity checks are suppressed. |
| |
| if Nkind (Lhs) in N_Selected_Component | N_Indexed_Component |
| and then not Validity_Check_Components |
| then |
| null; |
| else |
| Ensure_Valid (Rhs); |
| end if; |
| |
| -- We can propagate this to the left side where appropriate |
| |
| if Is_Local_Variable_Reference (Lhs) |
| and then not Is_Known_Valid (Entity (Lhs)) |
| and then In_Unconditional_Context (N) |
| then |
| Set_Is_Known_Valid (Entity (Lhs), True); |
| end if; |
| |
| -- Otherwise check to see what should be done |
| |
| -- If left side is a local variable, then we just set its flag to |
| -- indicate that its value may no longer be valid, since we are |
| -- copying a potentially invalid value. |
| |
| elsif Is_Local_Variable_Reference (Lhs) then |
| Set_Is_Known_Valid (Entity (Lhs), False); |
| |
| -- Check for case of a nonlocal variable on the left side which |
| -- is currently known to be valid. In this case, we simply ensure |
| -- that the right side is valid. We only play the game of copying |
| -- validity status for local variables, since we are doing this |
| -- statically, not by tracing the full flow graph. |
| |
| elsif Is_Entity_Name (Lhs) |
| and then Is_Known_Valid (Entity (Lhs)) |
| then |
| -- Note: If Validity_Checking mode is set to none, we ignore |
| -- the Ensure_Valid call so don't worry about that case here. |
| |
| Ensure_Valid (Rhs); |
| |
| -- In all other cases, we can safely copy an invalid value without |
| -- worrying about the status of the left side. Since it is not a |
| -- variable reference it will not be considered |
| -- as being known to be valid in any case. |
| |
| else |
| null; |
| end if; |
| end if; |
| end if; |
| |
| exception |
| when RE_Not_Available => |
| return; |
| end Expand_N_Assignment_Statement; |
| |
| ------------------------------ |
| -- Expand_N_Block_Statement -- |
| ------------------------------ |
| |
| -- Encode entity names defined in block statement |
| |
| procedure Expand_N_Block_Statement (N : Node_Id) is |
| begin |
| Qualify_Entity_Names (N); |
| end Expand_N_Block_Statement; |
| |
| ----------------------------- |
| -- Expand_N_Case_Statement -- |
| ----------------------------- |
| |
| procedure Expand_N_Case_Statement (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Expr : constant Node_Id := Expression (N); |
| From_Cond_Expr : constant Boolean := From_Conditional_Expression (N); |
| Alt : Node_Id; |
| Len : Nat; |
| Cond : Node_Id; |
| Choice : Node_Id; |
| Chlist : List_Id; |
| |
| function Expand_General_Case_Statement return Node_Id; |
| -- Expand a case statement whose selecting expression is not discrete |
| |
| ----------------------------------- |
| -- Expand_General_Case_Statement -- |
| ----------------------------------- |
| |
| function Expand_General_Case_Statement return Node_Id is |
| -- expand into a block statement |
| |
| Selector : constant Entity_Id := |
| Make_Temporary (Loc, 'J'); |
| |
| function Selector_Subtype_Mark return Node_Id is |
| (New_Occurrence_Of (Etype (Expr), Loc)); |
| |
| Renamed_Name : constant Node_Id := |
| (if Is_Name_Reference (Expr) |
| then Expr |
| else Make_Qualified_Expression (Loc, |
| Subtype_Mark => Selector_Subtype_Mark, |
| Expression => Expr)); |
| |
| Selector_Decl : constant Node_Id := |
| Make_Object_Renaming_Declaration (Loc, |
| Defining_Identifier => Selector, |
| Subtype_Mark => Selector_Subtype_Mark, |
| Name => Renamed_Name); |
| |
| First_Alt : constant Node_Id := First (Alternatives (N)); |
| |
| function Choice_Index_Decl_If_Needed return Node_Id; |
| -- If we are going to need a choice index object (that is, if |
| -- Multidefined_Bindings is true for at least one of the case |
| -- alternatives), then create and return that object's declaration. |
| -- Otherwise, return Empty; no need for a decl in that case because |
| -- it would never be referenced. |
| |
| --------------------------------- |
| -- Choice_Index_Decl_If_Needed -- |
| --------------------------------- |
| |
| function Choice_Index_Decl_If_Needed return Node_Id is |
| Alt : Node_Id := First_Alt; |
| begin |
| while Present (Alt) loop |
| if Multidefined_Bindings (Alt) then |
| return Make_Object_Declaration |
| (Sloc => Loc, |
| Defining_Identifier => |
| Make_Temporary (Loc, 'K'), |
| Object_Definition => |
| New_Occurrence_Of (Standard_Positive, Loc)); |
| end if; |
| |
| Next (Alt); |
| end loop; |
| return Empty; -- decl not needed |
| end Choice_Index_Decl_If_Needed; |
| |
| Choice_Index_Decl : constant Node_Id := Choice_Index_Decl_If_Needed; |
| |
| function Pattern_Match |
| (Pattern : Node_Id; |
| Object : Node_Id; |
| Choice_Index : Natural; |
| Alt : Node_Id; |
| Suppress_Choice_Index_Update : Boolean := False) return Node_Id; |
| -- Returns a Boolean-valued expression indicating a pattern match |
| -- for a given pattern and object. If Choice_Index is nonzero, |
| -- then Choice_Index is assigned to Choice_Index_Decl (unless |
| -- Suppress_Choice_Index_Update is specified, which should only |
| -- be the case for a recursive call where the caller has already |
| -- taken care of the update). Pattern occurs as a choice (or as a |
| -- subexpression of a choice) of the case statement alternative Alt. |
| |
| function Top_Level_Pattern_Match_Condition |
| (Alt : Node_Id) return Node_Id; |
| -- Returns a Boolean-valued expression indicating a pattern match |
| -- for the given alternative's list of choices. |
| |
| ------------------- |
| -- Pattern_Match -- |
| ------------------- |
| |
| function Pattern_Match |
| (Pattern : Node_Id; |
| Object : Node_Id; |
| Choice_Index : Natural; |
| Alt : Node_Id; |
| Suppress_Choice_Index_Update : Boolean := False) return Node_Id |
| is |
| procedure Finish_Binding_Object_Declaration |
| (Component_Assoc : Node_Id; Subobject : Node_Id); |
| -- Finish the work that was started during analysis to |
| -- declare a binding object. If we are generating a copy, |
| -- then initialize it. If we are generating a renaming, then |
| -- initialize the access value designating the renamed object. |
| |
| function Update_Choice_Index return Node_Id is ( |
| Make_Assignment_Statement (Loc, |
| Name => |
| New_Occurrence_Of |
| (Defining_Identifier (Choice_Index_Decl), Loc), |
| Expression => Make_Integer_Literal (Loc, Pos (Choice_Index)))); |
| |
| function PM |
| (Pattern : Node_Id; |
| Object : Node_Id; |
| Choice_Index : Natural := Pattern_Match.Choice_Index; |
| Alt : Node_Id := Pattern_Match.Alt; |
| Suppress_Choice_Index_Update : Boolean := |
| Pattern_Match.Suppress_Choice_Index_Update) return Node_Id |
| renames Pattern_Match; |
| -- convenient rename for recursive calls |
| |
| function Indexed_Element (Idx : Pos) return Node_Id; |
| -- Returns the Nth (well, ok, the Idxth) element of Object |
| |
| --------------------------------------- |
| -- Finish_Binding_Object_Declaration -- |
| --------------------------------------- |
| |
| procedure Finish_Binding_Object_Declaration |
| (Component_Assoc : Node_Id; Subobject : Node_Id) |
| is |
| Decl_Chars : constant Name_Id := |
| Binding_Chars (Component_Assoc); |
| |
| Block_Stmt : constant Node_Id := First (Statements (Alt)); |
| pragma Assert (Nkind (Block_Stmt) = N_Block_Statement); |
| pragma Assert (No (Next (Block_Stmt))); |
| |
| Decl : Node_Id := First (Declarations (Block_Stmt)); |
| Def_Id : Node_Id := Empty; |
| |
| function Declare_Copy (Decl : Node_Id) return Boolean is |
| (Nkind (Decl) = N_Object_Declaration); |
| -- Declare_Copy indicates which of the two approaches |
| -- was chosen during analysis: declare (and initialize) |
| -- a new variable, or use access values to declare a renaming |
| -- of the appropriate subcomponent of the selector value. |
| |
| function Make_Conditional (Stmt : Node_Id) return Node_Id; |
| -- If there is only one choice for this alternative, then |
| -- simply return the argument. If there is more than one |
| -- choice, then wrap an if-statement around the argument |
| -- so that it is only executed if the current choice matches. |
| |
| ---------------------- |
| -- Make_Conditional -- |
| ---------------------- |
| |
| function Make_Conditional (Stmt : Node_Id) return Node_Id |
| is |
| Condition : Node_Id; |
| begin |
| if Present (Choice_Index_Decl) then |
| Condition := |
| Make_Op_Eq (Loc, |
| New_Occurrence_Of |
| (Defining_Identifier (Choice_Index_Decl), Loc), |
| Make_Integer_Literal (Loc, Int (Choice_Index))); |
| |
| return Make_If_Statement (Loc, |
| Condition => Condition, |
| Then_Statements => New_List (Stmt)); |
| else |
| -- execute Stmt unconditionally |
| return Stmt; |
| end if; |
| end Make_Conditional; |
| |
| begin |
| -- find the variable to be modified (and its declaration) |
| loop |
| if Nkind (Decl) in N_Object_Declaration |
| | N_Object_Renaming_Declaration |
| then |
| Def_Id := Defining_Identifier (Decl); |
| exit when Chars (Def_Id) = Decl_Chars; |
| end if; |
| Next (Decl); |
| pragma Assert (Present (Decl)); |
| end loop; |
| |
| -- For a binding object, we sometimes make a copy and |
| -- sometimes introduce a renaming. That decision is made |
| -- elsewhere. The renaming case involves dereferencing an |
| -- access value because of the possibility of multiple |
| -- choices (with multiple binding definitions) for a single |
| -- alternative. In the copy case, we initialize the copy |
| -- here (conditionally if there are multiple choices); in the |
| -- renaming case, we initialize (again, maybe conditionally) |
| -- the access value. |
| |
| if Declare_Copy (Decl) then |
| declare |
| Assign_Value : constant Node_Id := |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Def_Id, Loc), |
| Expression => Subobject); |
| |
| HSS : constant Node_Id := |
| Handled_Statement_Sequence (Block_Stmt); |
| begin |
| Prepend (Make_Conditional (Assign_Value), |
| Statements (HSS)); |
| Set_Analyzed (HSS, False); |
| end; |
| else |
| pragma Assert (Nkind (Name (Decl)) = N_Explicit_Dereference); |
| |
| declare |
| Ptr_Obj : constant Entity_Id := |
| Entity (Prefix (Name (Decl))); |
| Ptr_Decl : constant Node_Id := Parent (Ptr_Obj); |
| |
| Assign_Reference : constant Node_Id := |
| Make_Assignment_Statement (Loc, |
| Name => New_Occurrence_Of (Ptr_Obj, Loc), |
| Expression => |
| Make_Attribute_Reference (Loc, |
| Prefix => Subobject, |
| Attribute_Name => Name_Unrestricted_Access)); |
| begin |
| Insert_After |
| (After => Ptr_Decl, |
| Node => Make_Conditional (Assign_Reference)); |
| |
| if Present (Expression (Ptr_Decl)) then |
| -- Delete bogus initial value built during analysis. |
| -- Look for "5432" in sem_case.adb. |
| pragma Assert (Nkind (Expression (Ptr_Decl)) = |
| N_Unchecked_Type_Conversion); |
| Set_Expression (Ptr_Decl, Empty); |
| end if; |
| end; |
| end if; |
| |
| Set_Analyzed (Block_Stmt, False); |
| end Finish_Binding_Object_Declaration; |
| |
| --------------------- |
| -- Indexed_Element -- |
| --------------------- |
| |
| function Indexed_Element (Idx : Pos) return Node_Id is |
| Obj_Index : constant Node_Id := |
| Make_Op_Add (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_First, |
| Prefix => New_Copy_Tree (Object)), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, Idx - 1)); |
| begin |
| return Make_Indexed_Component (Loc, |
| Prefix => New_Copy_Tree (Object), |
| Expressions => New_List (Obj_Index)); |
| end Indexed_Element; |
| |
| -- Start of processing for Pattern_Match |
| |
| begin |
| if Choice_Index /= 0 and not Suppress_Choice_Index_Update then |
| pragma Assert (Present (Choice_Index_Decl)); |
| |
| -- Add Choice_Index update as a side effect of evaluating |
| -- this condition and try again, this time suppressing |
| -- Choice_Index update. |
| |
| return Make_Expression_With_Actions (Loc, |
| Actions => New_List (Update_Choice_Index), |
| Expression => |
| PM (Pattern, Object, |
| Suppress_Choice_Index_Update => True)); |
| end if; |
| |
| if Nkind (Pattern) in N_Has_Etype |
| and then Is_Discrete_Type (Etype (Pattern)) |
| and then Compile_Time_Known_Value (Pattern) |
| then |
| declare |
| Val : Node_Id; |
| begin |
| if Is_Enumeration_Type (Etype (Pattern)) then |
| Val := Get_Enum_Lit_From_Pos |
| (Etype (Pattern), Expr_Value (Pattern), Loc); |
| else |
| Val := Make_Integer_Literal (Loc, Expr_Value (Pattern)); |
| end if; |
| return Make_Op_Eq (Loc, Object, Val); |
| end; |
| end if; |
| |
| case Nkind (Pattern) is |
| when N_Aggregate => |
| declare |
| Result : Node_Id; |
| begin |
| if Is_Array_Type (Etype (Pattern)) then |
| |
| -- Nonpositional aggregates currently unimplemented. |
| -- We flag that case during analysis, so an assertion |
| -- is ok here. |
| -- |
| pragma Assert |
| (not Is_Non_Empty_List |
| (Component_Associations (Pattern))); |
| |
| declare |
| Agg_Length : constant Node_Id := |
| Make_Integer_Literal (Loc, |
| List_Length (Expressions (Pattern))); |
| |
| Obj_Length : constant Node_Id := |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Length, |
| Prefix => New_Copy_Tree (Object)); |
| begin |
| Result := Make_Op_Eq (Loc, |
| Left_Opnd => Obj_Length, |
| Right_Opnd => Agg_Length); |
| end; |
| |
| declare |
| Expr : Node_Id := First (Expressions (Pattern)); |
| Idx : Pos := 1; |
| begin |
| while Present (Expr) loop |
| Result := |
| Make_And_Then (Loc, |
| Left_Opnd => Result, |
| Right_Opnd => |
| PM (Pattern => Expr, |
| Object => Indexed_Element (Idx))); |
| Next (Expr); |
| Idx := Idx + 1; |
| end loop; |
| end; |
| |
| return Result; |
| end if; |
| |
| -- positional notation should have been normalized |
| pragma Assert (No (Expressions (Pattern))); |
| |
| declare |
| Component_Assoc : Node_Id |
| := First (Component_Associations (Pattern)); |
| Choice : Node_Id; |
| |
| function Subobject return Node_Id is |
| (Make_Selected_Component (Loc, |
| Prefix => New_Copy_Tree (Object), |
| Selector_Name => New_Occurrence_Of |
| (Entity (Choice), Loc))); |
| begin |
| Result := New_Occurrence_Of (Standard_True, Loc); |
| |
| while Present (Component_Assoc) loop |
| Choice := First (Choices (Component_Assoc)); |
| while Present (Choice) loop |
| pragma Assert |
| (Is_Entity_Name (Choice) |
| and then Ekind (Entity (Choice)) |
| in E_Discriminant | E_Component); |
| |
| if Box_Present (Component_Assoc) then |
| -- Box matches anything |
| |
| pragma Assert |
| (No (Expression (Component_Assoc))); |
| else |
| Result := Make_And_Then (Loc, |
| Left_Opnd => Result, |
| Right_Opnd => |
| PM (Pattern => |
| Expression |
| (Component_Assoc), |
| Object => Subobject)); |
| end if; |
| |
| -- If this component association defines |
| -- (in the case where the pattern matches) |
| -- the value of a binding object, then |
| -- prepend to the statement list for this |
| -- alternative an assignment to the binding |
| -- object. This assignment will be conditional |
| -- if there is more than one choice. |
| |
| if Binding_Chars (Component_Assoc) /= No_Name |
| then |
| Finish_Binding_Object_Declaration |
| (Component_Assoc => Component_Assoc, |
| Subobject => Subobject); |
| end if; |
| |
| Next (Choice); |
| end loop; |
| |
| Next (Component_Assoc); |
| end loop; |
| end; |
| return Result; |
| end; |
| |
| when N_String_Literal => |
| return Result : Node_Id do |
| declare |
| Char_Type : constant Entity_Id := |
| Root_Type (Component_Type (Etype (Pattern))); |
| |
| -- If the component type is not a standard character |
| -- type then this string lit should have already been |
| -- transformed into an aggregate in |
| -- Resolve_String_Literal. |
| -- |
| pragma Assert (Is_Standard_Character_Type (Char_Type)); |
| |
| Str : constant String_Id := Strval (Pattern); |
| Strlen : constant Nat := String_Length (Str); |
| |
| Lit_Length : constant Node_Id := |
| Make_Integer_Literal (Loc, Strlen); |
| |
| Obj_Length : constant Node_Id := |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Length, |
| Prefix => New_Copy_Tree (Object)); |
| begin |
| Result := Make_Op_Eq (Loc, |
| Left_Opnd => Obj_Length, |
| Right_Opnd => Lit_Length); |
| |
| for Idx in 1 .. Strlen loop |
| declare |
| C : constant Char_Code := |
| Get_String_Char (Str, Idx); |
| Obj_Element : constant Node_Id := |
| Indexed_Element (Idx); |
| Char_Lit : Node_Id; |
| begin |
| Set_Character_Literal_Name (C); |
| Char_Lit := |
| Make_Character_Literal (Loc, |
| Chars => Name_Find, |
| Char_Literal_Value => UI_From_CC (C)); |
| |
| Result := |
| Make_And_Then (Loc, |
| Left_Opnd => Result, |
| Right_Opnd => |
| Make_Op_Eq (Loc, |
| Left_Opnd => Obj_Element, |
| Right_Opnd => Char_Lit)); |
| end; |
| end loop; |
| end; |
| end return; |
| |
| when N_Qualified_Expression => |
| return Make_And_Then (Loc, |
| Left_Opnd => Make_In (Loc, |
| Left_Opnd => New_Copy_Tree (Object), |
| Right_Opnd => New_Copy_Tree (Subtype_Mark (Pattern))), |
| Right_Opnd => |
| PM (Pattern => Expression (Pattern), |
| Object => New_Copy_Tree (Object))); |
| |
| when N_Identifier | N_Expanded_Name => |
| if Is_Type (Entity (Pattern)) then |
| return Make_In (Loc, |
| Left_Opnd => New_Copy_Tree (Object), |
| Right_Opnd => New_Occurrence_Of |
| (Entity (Pattern), Loc)); |
| elsif Ekind (Entity (Pattern)) = E_Constant then |
| return PM (Pattern => |
| Expression (Parent (Entity (Pattern))), |
| Object => Object); |
| end if; |
| |
| when N_Others_Choice => |
| return New_Occurrence_Of (Standard_True, Loc); |
| |
| when N_Type_Conversion => |
| -- aggregate expansion sometimes introduces conversions |
| if not Comes_From_Source (Pattern) |
| and then Base_Type (Etype (Pattern)) |
| = Base_Type (Etype (Expression (Pattern))) |
| then |
| return PM (Expression (Pattern), Object); |
| end if; |
| |
| when others => |
| null; |
| end case; |
| |
| -- Avoid cascading errors |
| pragma Assert (Serious_Errors_Detected > 0); |
| return New_Occurrence_Of (Standard_True, Loc); |
| end Pattern_Match; |
| |
| --------------------------------------- |
| -- Top_Level_Pattern_Match_Condition -- |
| --------------------------------------- |
| |
| function Top_Level_Pattern_Match_Condition |
| (Alt : Node_Id) return Node_Id |
| is |
| Top_Level_Object : constant Node_Id := |
| New_Occurrence_Of (Selector, Loc); |
| |
| Choices : constant List_Id := Discrete_Choices (Alt); |
| |
| First_Choice : constant Node_Id := First (Choices); |
| Subsequent : Node_Id := Next (First_Choice); |
| |
| Choice_Index : Natural := 0; |
| begin |
| if Multidefined_Bindings (Alt) then |
| Choice_Index := 1; |
| end if; |
| |
| return Result : Node_Id := |
| Pattern_Match (Pattern => First_Choice, |
| Object => Top_Level_Object, |
| Choice_Index => Choice_Index, |
| Alt => Alt) |
| do |
| while Present (Subsequent) loop |
| if Choice_Index /= 0 then |
| Choice_Index := Choice_Index + 1; |
| end if; |
| |
| Result := Make_Or_Else (Loc, |
| Left_Opnd => Result, |
| Right_Opnd => Pattern_Match |
| (Pattern => Subsequent, |
| Object => Top_Level_Object, |
| Choice_Index => Choice_Index, |
| Alt => Alt)); |
| Subsequent := Next (Subsequent); |
| end loop; |
| end return; |
| end Top_Level_Pattern_Match_Condition; |
| |
| function Elsif_Parts return List_Id; |
| -- Process subsequent alternatives |
| |
| ----------------- |
| -- Elsif_Parts -- |
| ----------------- |
| |
| function Elsif_Parts return List_Id is |
| Alt : Node_Id := First_Alt; |
| Result : constant List_Id := New_List; |
| begin |
| loop |
| Alt := Next (Alt); |
| exit when No (Alt); |
| |
| Append (Make_Elsif_Part (Loc, |
| Condition => Top_Level_Pattern_Match_Condition (Alt), |
| Then_Statements => Statements (Alt)), |
| Result); |
| end loop; |
| return Result; |
| end Elsif_Parts; |
| |
| function Else_Statements return List_Id; |
| -- Returns a "raise Constraint_Error" statement if |
| -- exception propagate is permitted and No_List otherwise. |
| |
| --------------------- |
| -- Else_Statements -- |
| --------------------- |
| |
| function Else_Statements return List_Id is |
| begin |
| if Restriction_Active (No_Exception_Propagation) then |
| return No_List; |
| else |
| return New_List (Make_Raise_Constraint_Error (Loc, |
| Reason => CE_Invalid_Data)); |
| end if; |
| end Else_Statements; |
| |
| -- Local constants |
| |
| If_Stmt : constant Node_Id := |
| Make_If_Statement (Loc, |
| Condition => Top_Level_Pattern_Match_Condition (First_Alt), |
| Then_Statements => Statements (First_Alt), |
| Elsif_Parts => Elsif_Parts, |
| Else_Statements => Else_Statements); |
| |
| Declarations : constant List_Id := New_List (Selector_Decl); |
| |
| -- Start of processing for Expand_General_Case_Statment |
| |
| begin |
| if Present (Choice_Index_Decl) then |
| Append_To (Declarations, Choice_Index_Decl); |
| end if; |
| |
| return Make_Block_Statement (Loc, |
| Declarations => Declarations, |
| Handled_Statement_Sequence => |
| Make_Handled_Sequence_Of_Statements (Loc, |
| Statements => New_List (If_Stmt))); |
| end Expand_General_Case_Statement; |
| |
| -- Start of processing for Expand_N_Case_Statement |
| |
| begin |
| if Extensions_Allowed and then not Is_Discrete_Type (Etype (Expr)) then |
| Rewrite (N, Expand_General_Case_Statement); |
| Analyze (N); |
| return; |
| end if; |
| |
| -- Check for the situation where we know at compile time which branch |
| -- will be taken. |
| |
| -- If the value is static but its subtype is predicated and the value |
| -- does not obey the predicate, the value is marked non-static, and |
| -- there can be no corresponding static alternative. In that case we |
| -- replace the case statement with an exception, regardless of whether |
| -- assertions are enabled or not, unless predicates are ignored. |
| |
| if Compile_Time_Known_Value (Expr) |
| and then Has_Predicates (Etype (Expr)) |
| and then not Predicates_Ignored (Etype (Expr)) |
| and then not Is_OK_Static_Expression (Expr) |
| then |
| Rewrite (N, |
| Make_Raise_Constraint_Error (Loc, Reason => CE_Invalid_Data)); |
| Analyze (N); |
| return; |
| |
| elsif Compile_Time_Known_Value (Expr) |
| and then (not Has_Predicates (Etype (Expr)) |
| or else Is_Static_Expression (Expr)) |
| then |
| Alt := Find_Static_Alternative (N); |
| |
| -- Do not consider controlled objects found in a case statement which |
| -- actually models a case expression because their early finalization |
| -- will affect the result of the expression. |
| |
| if not From_Conditional_Expression (N) then |
| Process_Statements_For_Controlled_Objects (Alt); |
| end if; |
| |
| -- Move statements from this alternative after the case statement. |
| -- They are already analyzed, so will be skipped by the analyzer. |
| |
| Insert_List_After (N, Statements (Alt)); |
| |
| -- That leaves the case statement as a shell. So now we can kill all |
| -- other alternatives in the case statement. |
| |
| Kill_Dead_Code (Expression (N)); |
| |
| declare |
| Dead_Alt : Node_Id; |
| |
| begin |
| -- Loop through case alternatives, skipping pragmas, and skipping |
| -- the one alternative that we select (and therefore retain). |
| |
| Dead_Alt := First (Alternatives (N)); |
| while Present (Dead_Alt) loop |
| if Dead_Alt /= Alt |
| and then Nkind (Dead_Alt) = N_Case_Statement_Alternative |
| then |
| Kill_Dead_Code (Statements (Dead_Alt), Warn_On_Deleted_Code); |
| end if; |
| |
| Next (Dead_Alt); |
| end loop; |
| end; |
| |
| Rewrite (N, Make_Null_Statement (Loc)); |
| return; |
| end if; |
| |
| -- Here if the choice is not determined at compile time |
| |
| declare |
| Last_Alt : constant Node_Id := Last (Alternatives (N)); |
| |
| Others_Present : Boolean; |
| Others_Node : Node_Id; |
| |
| Then_Stms : List_Id; |
| Else_Stms : List_Id; |
| |
| begin |
| if Nkind (First (Discrete_Choices (Last_Alt))) = N_Others_Choice then |
| Others_Present := True; |
| Others_Node := Last_Alt; |
| else |
| Others_Present := False; |
| end if; |
| |
| -- First step is to worry about possible invalid argument. The RM |
| -- requires (RM 5.4(13)) that if the result is invalid (e.g. it is |
| -- outside the base range), then Constraint_Error must be raised. |
| |
| -- Case of validity check required (validity checks are on, the |
| -- expression is not known to be valid, and the case statement |
| -- comes from source -- no need to validity check internally |
| -- generated case statements). |
| |
| if Validity_Check_Default |
| and then not Predicates_Ignored (Etype (Expr)) |
| then |
| -- Recognize the simple case where Expr is an object reference |
| -- and the case statement is directly preceded by an |
| -- "if Obj'Valid then": in this case, do not emit another validity |
| -- check. |
| |
| declare |
| Check_Validity : Boolean := True; |
| Attr : Node_Id; |
| begin |
| if Nkind (Expr) = N_Identifier |
| and then Nkind (Parent (N)) = N_If_Statement |
| and then Nkind (Original_Node (Condition (Parent (N)))) |
| = N_Attribute_Reference |
| and then No (Prev (N)) |
| then |
| Attr := Original_Node (Condition (Parent (N))); |
| |
| if Attribute_Name (Attr) = Name_Valid |
| and then Nkind (Prefix (Attr)) = N_Identifier |
| and then Entity (Prefix (Attr)) = Entity (Expr) |
| then |
| Check_Validity := False; |
| end if; |
| end if; |
| |
| if Check_Validity then |
| Ensure_Valid (Expr); |
| end if; |
| end; |
| end if; |
| |
| -- If there is only a single alternative, just replace it with the |
| -- sequence of statements since obviously that is what is going to |
| -- be executed in all cases. |
| |
| Len := List_Length (Alternatives (N)); |
| |
| if Len = 1 then |
| |
| -- We still need to evaluate the expression if it has any side |
| -- effects. |
| |
| Remove_Side_Effects (Expression (N)); |
| Alt := First (Alternatives (N)); |
| |
| -- Do not consider controlled objects found in a case statement |
| -- which actually models a case expression because their early |
| -- finalization will affect the result of the expression. |
| |
| if not From_Conditional_Expression (N) then |
| Process_Statements_For_Controlled_Objects (Alt); |
| end if; |
| |
| Insert_List_After (N, Statements (Alt)); |
| |
| -- That leaves the case statement as a shell. The alternative that |
| -- will be executed is reset to a null list. So now we can kill |
| -- the entire case statement. |
| |
| Kill_Dead_Code (Expression (N)); |
| Rewrite (N, Make_Null_Statement (Loc)); |
| return; |
| |
| -- An optimization. If there are only two alternatives, and only |
| -- a single choice, then rewrite the whole case statement as an |
| -- if statement, since this can result in subsequent optimizations. |
| -- This helps not only with case statements in the source of a |
| -- simple form, but also with generated code (discriminant check |
| -- functions in particular). |
| |
| -- Note: it is OK to do this before expanding out choices for any |
| -- static predicates, since the if statement processing will handle |
| -- the static predicate case fine. |
| |
| elsif Len = 2 then |
| Chlist := Discrete_Choices (First (Alternatives (N))); |
| |
| if List_Length (Chlist) = 1 then |
| Choice := First (Chlist); |
| |
| Then_Stms := Statements (First (Alternatives (N))); |
| Else_Stms := Statements (Last (Alternatives (N))); |
| |
| -- For TRUE, generate "expression", not expression = true |
| |
| if Nkind (Choice) = N_Identifier |
| and then Entity (Choice) = Standard_True |
| then |
| Cond := Expression (N); |
| |
| -- For FALSE, generate "expression" and switch then/else |
| |
| elsif Nkind (Choice) = N_Identifier |
| and then Entity (Choice) = Standard_False |
| then |
| Cond := Expression (N); |
| Else_Stms := Statements (First (Alternatives (N))); |
| Then_Stms := Statements (Last (Alternatives (N))); |
| |
| -- For a range, generate "expression in range" |
| |
| elsif Nkind (Choice) = N_Range |
| or else (Nkind (Choice) = N_Attribute_Reference |
| and then Attribute_Name (Choice) = Name_Range) |
| or else (Is_Entity_Name (Choice) |
| and then Is_Type (Entity (Choice))) |
| then |
| Cond := |
| Make_In (Loc, |
| Left_Opnd => Expression (N), |
| Right_Opnd => Relocate_Node (Choice)); |
| |
| -- A subtype indication is not a legal operator in a membership |
| -- test, so retrieve its range. |
| |
| elsif Nkind (Choice) = N_Subtype_Indication then |
| Cond := |
| Make_In (Loc, |
| Left_Opnd => Expression (N), |
| Right_Opnd => |
| Relocate_Node |
| (Range_Expression (Constraint (Choice)))); |
| |
| -- For any other subexpression "expression = value" |
| |
| else |
| Cond := |
| Make_Op_Eq (Loc, |
| Left_Opnd => Expression (N), |
| Right_Opnd => Relocate_Node (Choice)); |
| end if; |
| |
| -- Now rewrite the case as an IF |
| |
| Rewrite (N, |
| Make_If_Statement (Loc, |
| Condition => Cond, |
| Then_Statements => Then_Stms, |
| Else_Statements => Else_Stms)); |
| |
| -- The rewritten if statement needs to inherit whether the |
| -- case statement was expanded from a conditional expression, |
| -- for proper handling of nested controlled objects. |
| |
| Set_From_Conditional_Expression (N, From_Cond_Expr); |
| |
| Analyze (N); |
| |
| return; |
| end if; |
| end if; |
| |
| -- If the last alternative is not an Others choice, replace it with |
| -- an N_Others_Choice. Note that we do not bother to call Analyze on |
| -- the modified case statement, since it's only effect would be to |
| -- compute the contents of the Others_Discrete_Choices which is not |
| -- needed by the back end anyway. |
| |
| -- The reason for this is that the back end always needs some default |
| -- for a switch, so if we have not supplied one in the processing |
| -- above for validity checking, then we need to supply one here. |
| |
| if not Others_Present then |
| Others_Node := Make_Others_Choice (Sloc (Last_Alt)); |
| |
| -- If Predicates_Ignored is true the value does not satisfy the |
| -- predicate, and there is no Others choice, Constraint_Error |
| -- must be raised (4.5.7 (21/3)). |
| |
| if Predicates_Ignored (Etype (Expr)) then |
| declare |
| Except : constant Node_Id := |
| Make_Raise_Constraint_Error (Loc, |
| Reason => CE_Invalid_Data); |
| New_Alt : constant Node_Id := |
| Make_Case_Statement_Alternative (Loc, |
| Discrete_Choices => New_List ( |
| Make_Others_Choice (Loc)), |
| Statements => New_List (Except)); |
| |
| begin |
| Append (New_Alt, Alternatives (N)); |
| Analyze_And_Resolve (Except); |
| end; |
| |
| else |
| Set_Others_Discrete_Choices |
| (Others_Node, Discrete_Choices (Last_Alt)); |
| Set_Discrete_Choices (Last_Alt, New_List (Others_Node)); |
| end if; |
| |
| end if; |
| |
| -- Deal with possible declarations of controlled objects, and also |
| -- with rewriting choice sequences for static predicate references. |
| |
| Alt := First_Non_Pragma (Alternatives (N)); |
| while Present (Alt) loop |
| |
| -- Do not consider controlled objects found in a case statement |
| -- which actually models a case expression because their early |
| -- finalization will affect the result of the expression. |
| |
| if not From_Conditional_Expression (N) then |
| Process_Statements_For_Controlled_Objects (Alt); |
| end if; |
| |
| if Has_SP_Choice (Alt) then |
| Expand_Static_Predicates_In_Choices (Alt); |
| end if; |
| |
| Next_Non_Pragma (Alt); |
| end loop; |
| end; |
| end Expand_N_Case_Statement; |
| |
| ----------------------------- |
| -- Expand_N_Exit_Statement -- |
| ----------------------------- |
| |
| -- The only processing required is to deal with a possible C/Fortran |
| -- boolean value used as the condition for the exit statement. |
| |
| procedure Expand_N_Exit_Statement (N : Node_Id) is |
| begin |
| Adjust_Condition (Condition (N)); |
| end Expand_N_Exit_Statement; |
| |
| ---------------------------------- |
| -- Expand_Formal_Container_Loop -- |
| ---------------------------------- |
| |
| procedure Expand_Formal_Container_Loop (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Isc : constant Node_Id := Iteration_Scheme (N); |
| I_Spec : constant Node_Id := Iterator_Specification (Isc); |
| Cursor : constant Entity_Id := Defining_Identifier (I_Spec); |
| Container : constant Node_Id := Entity (Name (I_Spec)); |
| Stats : constant List_Id := Statements (N); |
| |
| Advance : Node_Id; |
| Init_Decl : Node_Id; |
| |