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[Ada] Fix type mismatch in extended return statement expansion 

This fixes a (sub)type mismatch in the expansion of an extended return
statement generated for a built-in-place function that doesn't need a
BIP_Alloc_Form parameter but returns unconstrained.

No functional changes.

2019-08-21  Eric Botcazou  <ebotcazou@adacore.com>

gcc/ada/

	* exp_ch6.adb (Expand_N_Extended_Return_Statement): In the case
	of a built-in-place function that doesn't need a BIP_Alloc_Form
	parameter but returns unconstrained, build the return
	consistently using the function's result subtype.  Remove bypass
	added in previous change.

From-SVN: r274782
This commit is contained in:
Eric Botcazou 2019-08-21 08:30:00 +00:00 committed by Pierre-Marie de Rodat
parent 92ef57728e
commit bde9a2c227
2 changed files with 68 additions and 25 deletions
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8
gcc/ada/ChangeLog
View File

@ -1,3 +1,11 @@
2019-08-21 Eric Botcazou <ebotcazou@adacore.com>
* exp_ch6.adb (Expand_N_Extended_Return_Statement): In the case
of a built-in-place function that doesn't need a BIP_Alloc_Form
parameter but returns unconstrained, build the return
consistently using the function's result subtype. Remove bypass
added in previous change.
2019-08-21 Piotr Trojanek <trojanek@adacore.com>
* sem_prag.adb (Max_Entry_Queue_Length): Do not substitute

85
gcc/ada/exp_ch6.adb
View File

@ -5199,7 +5199,7 @@ package body Exp_Ch6 is
end if;
-- When the function's subtype is unconstrained, a run-time
-- test is needed to determine the form of allocation to use
-- test may be needed to decide the form of allocation to use
-- for the return object. The function has an implicit formal
-- parameter indicating this. If the BIP_Alloc_Form formal has
-- the value one, then the caller has passed access to an
@ -5235,13 +5235,6 @@ package body Exp_Ch6 is
SS_Allocator : Node_Id;
begin
-- Reuse the itype created for the function's implicit
-- access formal. This avoids the need to create a new
-- access type here, plus it allows assigning the access
-- formal directly without applying a conversion.
-- Ref_Type := Etype (Object_Access);
-- Create an access type designating the function's
-- result subtype.
@ -5570,6 +5563,64 @@ package body Exp_Ch6 is
-- Remember the local access object for use in the
-- dereference of the renaming created below.
Obj_Acc_Formal := Alloc_Obj_Id;
end;
-- When the function's subtype is unconstrained and a run-time
-- test is not needed, we nevertheless need to build the return
-- using the function's result subtype.
elsif not Is_Constrained (Underlying_Type (Etype (Func_Id)))
then
declare
Alloc_Obj_Id : Entity_Id;
Alloc_Obj_Decl : Node_Id;
Ptr_Type_Decl : Node_Id;
Ref_Type : Entity_Id;
begin
-- Create an access type designating the function's
-- result subtype.
Ref_Type := Make_Temporary (Loc, 'A');
Ptr_Type_Decl :=
Make_Full_Type_Declaration (Loc,
Defining_Identifier => Ref_Type,
Type_Definition =>
Make_Access_To_Object_Definition (Loc,
All_Present => True,
Subtype_Indication =>
New_Occurrence_Of (Ret_Obj_Typ, Loc)));
Insert_Before (Ret_Obj_Decl, Ptr_Type_Decl);
-- Create an access object initialized to the conversion
-- of the implicit access value passed in by the caller.
Alloc_Obj_Id := Make_Temporary (Loc, 'R');
Set_Etype (Alloc_Obj_Id, Ref_Type);
-- See the ??? comment a few lines above about the use of
-- an unchecked conversion here.
Alloc_Obj_Decl :=
Make_Object_Declaration (Loc,
Defining_Identifier => Alloc_Obj_Id,
Object_Definition =>
New_Occurrence_Of (Ref_Type, Loc),
Expression =>
Make_Unchecked_Type_Conversion (Loc,
Subtype_Mark =>
New_Occurrence_Of (Ref_Type, Loc),
Expression =>
New_Occurrence_Of (Obj_Acc_Formal, Loc)));
Insert_Before (Ret_Obj_Decl, Alloc_Obj_Decl);
-- Remember the local access object for use in the
-- dereference of the renaming created below.
Obj_Acc_Formal := Alloc_Obj_Id;
end;
end if;
@ -5615,23 +5666,7 @@ package body Exp_Ch6 is
Set_Comes_From_Extended_Return_Statement (Return_Stmt);
Rewrite (N, Result);
declare
T : constant Entity_Id := Etype (Ret_Obj_Id);
begin
Analyze (N, Suppress => All_Checks);
-- In some cases, analysis of N can set the Etype of an N_Identifier
-- to a subtype of the Etype of the Entity of the N_Identifier, which
-- gigi doesn't like. Reset the Etypes correctly here.
if Nkind (Expression (Return_Stmt)) = N_Identifier
and then Entity (Expression (Return_Stmt)) = Ret_Obj_Id
then
Set_Etype (Ret_Obj_Id, T);
Set_Etype (Expression (Return_Stmt), T);
end if;
end;
Analyze (N, Suppress => All_Checks);
end Expand_N_Extended_Return_Statement;
----------------------------