https://gcc.gnu.org/g:911d921759e4a32bac81016b2dda1e26147ba5d8
commit r15-199-g911d921759e4a32bac81016b2dda1e26147ba5d8
Author: Gary Dismukes <dismu...@adacore.com>
Date: Thu Jan 4 00:34:33 2024 +0000
ada: Excess finalization on return of call to dispatching constructor
The compiler expands a too-early finalization call for the result
object of an extended return statement that returns a call to a
dispatching constructor function for a limited interface type,
resulting in premature (and extra) finalization of the result.
The temporary object that the compiler creates to hold the result
of the build-in-place call loses the fact that it comes from a
return, and the wrong BIP allocation form may be passed in the
call to the dispatching constructor, and the later code for dealing
with finalization in Exp_Ch7.Build_Finalizer incorrectly finalizes
the result object.
gcc/ada/
* exp_ch6.adb
(Make_Build_In_Place_Iface_Call_In_Object_Declaration): Set the
Is_Return_Object flag on the entity of the temp object created to
hold the BIP call result, from the flag on the passed-in object
declaration's entity. Update copyright notice to 2024.
Diff:
---
gcc/ada/exp_ch6.adb | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/gcc/ada/exp_ch6.adb b/gcc/ada/exp_ch6.adb
index fcfd1d7f0bf..a89c9af0bb2 100644
--- a/gcc/ada/exp_ch6.adb
+++ b/gcc/ada/exp_ch6.adb
@@ -9393,6 +9393,16 @@ package body Exp_Ch6 is
Insert_Action (Obj_Decl, Tmp_Decl);
Expander_Mode_Restore;
+ -- Inherit Is_Return_Object from the parent object to the temp object,
+ -- so that Make_In_Build_Place_Call_In_Object_Declaration will handle
+ -- the temp properly in cases where there's a BIP_Alloc_Form formal of
+ -- an enclosing function that should be passed along (and which also
+ -- ensures that if the BIP call is used as a function result and it
+ -- requires finalization, then it will not be finalized prematurely
+ -- or redundantly).
+
+ Set_Is_Return_Object (Tmp_Id, Is_Return_Object (Obj_Id));
+
Make_Build_In_Place_Call_In_Object_Declaration
(Obj_Decl => Tmp_Decl,
Function_Call => Expression (Tmp_Decl));
