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* [gcc r13-5011] ada: Fix finalization issues in extended return statements
@ 2023-01-05 14:37 Marc Poulhi?s
0 siblings, 0 replies; only message in thread
From: Marc Poulhi?s @ 2023-01-05 14:37 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:d990f34e93172b040de29c65e6d72572e73d00f0
commit r13-5011-gd990f34e93172b040de29c65e6d72572e73d00f0
Author: Eric Botcazou <ebotcazou@adacore.com>
Date: Wed Dec 14 15:16:21 2022 +0100
ada: Fix finalization issues in extended return statements
The first issue pertains to return objects of (class-wide) interface types,
which need to be adjusted if the type is not inherently limited. The second
issue is for return objects of non-class-wide types that are initialized by
a function call, which can use a direct renaming only if the object doing
the capture of the function call is flagged by Is_Related_To_Func_Return.
The third one is that, in the second case, we may need to reassign the tag.
gcc/ada/
* exp_ch3.adb (Expand_N_Object_Declaration): For a special return
object of an interface type that is not inherently limited, make
a call to the Adjust primitive after doing the copy. For a special
return object of a non-class-wide type initialized by a function
call, use a direct renaming only if the object doing the capture
is flagged by Is_Related_To_Func_Return. For a special return
object using a direct renaming, reassign the tag, if need be.
* exp_ch6.adb (Expand_Simple_Function_Return): Fix comment.
* exp_util.adb (Is_Related_To_Func_Return): Accept both regular and
renaming object declarations for return objects.
Diff:
---
gcc/ada/exp_ch3.adb | 34 ++++++++++++++++++++++++++++++++--
gcc/ada/exp_ch6.adb | 2 +-
gcc/ada/exp_util.adb | 3 ++-
3 files changed, 35 insertions(+), 4 deletions(-)
diff --git a/gcc/ada/exp_ch3.adb b/gcc/ada/exp_ch3.adb
index def63ed0513..7dbf82671aa 100644
--- a/gcc/ada/exp_ch3.adb
+++ b/gcc/ada/exp_ch3.adb
@@ -7480,7 +7480,19 @@ package body Exp_Ch3 is
-- creating the object (via allocator) and initializing it.
if Is_Special_Return_Object (Def_Id) then
- null;
+
+ -- If the type needs finalization and is not inherently
+ -- limited, then the target is adjusted after the copy
+ -- and attached to the finalization list.
+
+ if Needs_Finalization (Typ)
+ and then not Is_Limited_View (Typ)
+ then
+ Adj_Call :=
+ Make_Adjust_Call (
+ Obj_Ref => New_Occurrence_Of (Def_Id, Loc),
+ Typ => Base_Typ);
+ end if;
elsif Tagged_Type_Expansion then
declare
@@ -7908,9 +7920,20 @@ package body Exp_Ch3 is
-- This avoids an extra copy and, in the case where Typ needs
-- finalization, a pair of Adjust/Finalize calls (see below).
+ -- However, in the case of a special return object, we need to
+ -- make sure that the object Rnn is properly recognized by the
+ -- Is_Related_To_Func_Return predicate; otherwise, if it is of
+ -- a type that needs finalization, Requires_Cleanup_Actions
+ -- would return true because of this and Build_Finalizer would
+ -- finalize it prematurely (see Expand_Simple_Function_Return
+ -- for the same test in the case of a simple return).
+
and then
((not Is_Library_Level_Entity (Def_Id)
and then Is_Captured_Function_Call (Expr_Q)
+ and then (not Is_Special_Return_Object (Def_Id)
+ or else Is_Related_To_Func_Return
+ (Entity (Prefix (Expr_Q))))
and then not Is_Class_Wide_Type (Typ))
-- If the initializing expression is a variable with the
@@ -8554,7 +8577,8 @@ package body Exp_Ch3 is
-- If we can rename the initialization expression, we need to make sure
-- that we use the proper type in the case of a return object that lives
- -- on the secondary stack. See other cases below for a similar handling.
+ -- on the secondary stack (see other cases below for a similar handling)
+ -- and that the tag is assigned in the case of any return object.
elsif Rewrite_As_Renaming then
if Is_Secondary_Stack_Return_Object (Def_Id) then
@@ -8577,6 +8601,12 @@ package body Exp_Ch3 is
end;
end if;
+ if Is_Special_Return_Object (Def_Id)
+ and then Present (Tag_Assign)
+ then
+ Insert_Action_After (Init_After, Tag_Assign);
+ end if;
+
-- If this is the return object of a function returning on the secondary
-- stack, convert the declaration to a renaming of the dereference of ah
-- allocator for the secondary stack.
diff --git a/gcc/ada/exp_ch6.adb b/gcc/ada/exp_ch6.adb
index db1fd1d172b..b97d69b81b6 100644
--- a/gcc/ada/exp_ch6.adb
+++ b/gcc/ada/exp_ch6.adb
@@ -6449,7 +6449,7 @@ package body Exp_Ch6 is
-- sure that the object doing the capture is properly recognized by the
-- Is_Related_To_Func_Return predicate; otherwise, if it is of a type
-- that needs finalization, Requires_Cleanup_Actions would return true
- -- because of it and Build_Finalizer would finalize it prematurely.
+ -- because of this and Build_Finalizer would finalize it prematurely.
Exp_Typ : constant Entity_Id := Etype (Exp);
-- The type of the expression (not necessarily the same as R_Type)
diff --git a/gcc/ada/exp_util.adb b/gcc/ada/exp_util.adb
index 3c68f917ca9..c8829cac85a 100644
--- a/gcc/ada/exp_util.adb
+++ b/gcc/ada/exp_util.adb
@@ -9196,7 +9196,8 @@ package body Exp_Util is
and then Nkind (Unqual_Conv (Expr)) = N_Explicit_Dereference
and then (Nkind (Parent (Expr)) = N_Simple_Return_Statement
or else
- (Nkind (Parent (Expr)) = N_Object_Renaming_Declaration
+ (Nkind (Parent (Expr)) in N_Object_Declaration
+ | N_Object_Renaming_Declaration
and then
Is_Return_Object (Defining_Entity (Parent (Expr)))));
end Is_Related_To_Func_Return;
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