[Bug c++/114935] [14/15 regression] Miscompilation of initializer_list in presence of exceptions since r14-1705-g2764335bd336f2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114935 --- Comment #5 from Jason Merrill --- Created attachment 58210 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58210=edit attempt to reduce redundancy A failed attempt to avoid duplicate array cleanups in this case.
[Bug c++/114935] [14/15 regression] Miscompilation of initializer_list in presence of exceptions since r14-1705-g2764335bd336f2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114935 Jason Merrill changed: What|Removed |Added Resolution|--- |FIXED Status|ASSIGNED|RESOLVED --- Comment #4 from Jason Merrill --- Fixed.
[Bug c++/114935] [14/15 regression] Miscompilation of initializer_list in presence of exceptions since r14-1705-g2764335bd336f2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114935 --- Comment #3 from GCC Commits --- The releases/gcc-14 branch has been updated by Jason Merrill : https://gcc.gnu.org/g:3b4d6b6ecd79df790bf0938dab1f51094f94d777 commit r14-10165-g3b4d6b6ecd79df790bf0938dab1f51094f94d777 Author: Jason Merrill Date: Fri May 3 09:52:46 2024 -0400 c++: initializer_list and EH [PR114935] When we initialize an array of a type with a non-trivial destructor, such as the backing array for the initializer_list, we have a cleanup to destroy any constructed elements if a later constructor throws. When the array being created is a variable, the end of that EH region naturally coincides with the beginning of the EH region for the cleanup for the variable as a whole. But if the array is a temporary, or a subobject of one, the array cleanup region lasts for the rest of the full-expression, along with the normal cleanup for the TARGET_EXPR. As a result, when tata throws we clean it up twice. Before r14-1705 we avoided this by disabling the array cleanup in split_nonconstant_init, but after that we don't go through split_nonconstant_init, so let's handle it in cp_genericize_target_expr. PR c++/114935 gcc/cp/ChangeLog: * cp-gimplify.cc (cp_genericize_init): Add flags parm. (cp_genericize_init_expr): Pass nullptr. (cp_genericize_target_expr): Handle cleanup flags. * typeck2.cc (build_disable_temp_cleanup): Factor out of... (split_nonconstant_init): ...here. * cp-tree.h (build_disable_temp_cleanup): Declare. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/initlist-eh1.C: New test. (cherry picked from commit 8f3afb83c879f1bfa722a963a07c06aaf174ef72)
[Bug c++/114935] [14/15 regression] Miscompilation of initializer_list in presence of exceptions since r14-1705-g2764335bd336f2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114935 --- Comment #2 from GCC Commits --- The trunk branch has been updated by Jason Merrill : https://gcc.gnu.org/g:8f3afb83c879f1bfa722a963a07c06aaf174ef72 commit r15-138-g8f3afb83c879f1bfa722a963a07c06aaf174ef72 Author: Jason Merrill Date: Fri May 3 09:52:46 2024 -0400 c++: initializer_list and EH [PR114935] When we initialize an array of a type with a non-trivial destructor, such as the backing array for the initializer_list, we have a cleanup to destroy any constructed elements if a later constructor throws. When the array being created is a variable, the end of that EH region naturally coincides with the beginning of the EH region for the cleanup for the variable as a whole. But if the array is a temporary, or a subobject of one, the array cleanup region lasts for the rest of the full-expression, along with the normal cleanup for the TARGET_EXPR. As a result, when tata throws we clean it up twice. Before r14-1705 we avoided this by disabling the array cleanup in split_nonconstant_init, but after that we don't go through split_nonconstant_init, so let's handle it in cp_genericize_target_expr. PR c++/114935 gcc/cp/ChangeLog: * cp-gimplify.cc (cp_genericize_init): Add flags parm. (cp_genericize_init_expr): Pass nullptr. (cp_genericize_target_expr): Handle cleanup flags. * typeck2.cc (build_disable_temp_cleanup): Factor out of... (split_nonconstant_init): ...here. * cp-tree.h (build_disable_temp_cleanup): Declare. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/initlist-eh1.C: New test.
[Bug c++/114935] [14/15 regression] Miscompilation of initializer_list in presence of exceptions since r14-1705-g2764335bd336f2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114935
--- Comment #1 from Jason Merrill ---
Without :
#include
int as;
struct A {
A(const char *) { ++as; }
A(const A&) { ++as; }
~A() { --as; }
};
void __attribute__((noipa))
tata(std::initializer_list init)
{
throw 1;
}
int
main()
{
try { tata({ "foo","bar" }); }
catch (...) { }
if (as != 0) __builtin_abort ();
}
The problem is with the array EH cleanup handling: when we initialize an array
of a type with a non-trivial destructor, such as the backing array for the
initializer_list, we have a cleanup to destroy any constructed elements if a
later constructor throws. But in this case the call to tata is still in that
region. Without the r14-1705 change, we deal with that by disabling the array
cleanup in split_nonconstant_init, but with the change we don't go through
split_nonconstant_init and so we miss disabling the cleanup.
