From: Eric Botcazou <ebotca...@adacore.com>
The special handling of temporaries created for return values and subject
to a renaming needs to be restricted to the top level, where it is needed
to prevent dangling references to the frame of the elaboration routine from
being created, because, at a lower level, the front-end may create implicit
renamings of objects as these temporaries, so a copy is not allowed.
gcc/ada/
* gcc-interface/decl.cc (gnat_to_gnu_entity) <E_Variable>: Restrict
the special handling of temporaries created for return values and
subject to a renaming to the top level.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/gcc-interface/decl.cc | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/gcc/ada/gcc-interface/decl.cc b/gcc/ada/gcc-interface/decl.cc
index e5e04ddad93..b2b77787bc0 100644
--- a/gcc/ada/gcc-interface/decl.cc
+++ b/gcc/ada/gcc-interface/decl.cc
@@ -1076,9 +1076,13 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree
gnu_expr, bool definition)
|| EXPRESSION_CLASS_P (inner)
/* We need to detect the case where a temporary is created to
hold the return value, since we cannot safely rename it at
- top level as it lives only in the elaboration routine. */
+ top level because it lives only in the elaboration routine.
+ But, at a lower level, an object initialized by a function
+ call may be (implicitly) renamed as this temporary by the
+ front-end and, in this case, we cannot make a copy. */
|| (VAR_P (inner)
- && DECL_RETURN_VALUE_P (inner))
+ && DECL_RETURN_VALUE_P (inner)
+ && global_bindings_p ())
/* We also need to detect the case where the front-end creates
a dangling 'reference to a function call at top level and
substitutes it in the renaming, for example:
@@ -1092,12 +1096,14 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree
gnu_expr, bool definition)
q__b : boolean renames q__R1s.all.e (1);
We cannot safely rename the rewritten expression since the
- underlying object lives only in the elaboration routine. */
+ underlying object lives only in the elaboration routine but,
+ as above, this cannot be done at a lower level. */
|| (INDIRECT_REF_P (inner)
&& (inner
= remove_conversions (TREE_OPERAND (inner, 0), true))
&& VAR_P (inner)
- && DECL_RETURN_VALUE_P (inner)))
+ && DECL_RETURN_VALUE_P (inner)
+ && global_bindings_p ()))
;
/* Otherwise, this is an lvalue being renamed, so it needs to be
--
2.40.0
