https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110728
Bug ID: 110728
Summary: should __attribute__((cleanup())) callback get invoked
for indirect edges of asm goto
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: ndesaulniers at google dot com
Target Milestone: ---
Consider the following test case:
```c
void test4cleanup(int*);
// No errors expected.
void test4(void) {
l0:;
int x __attribute__((cleanup(test4cleanup)));
asm goto("# %l0"::::l0);
}
```
gcc trunk today generates effectively the following control flow:
```
test4:
.LFB0:
subq $24, %rsp
.L2:
#APP
# .L2
#NO_APP
leaq 12(%rsp), %rdi
call test4cleanup
addq $24, %rsp
ret
```
so if the inline asm blob jumps to `l0`, then the cleanup function is not run.
That seemed surprising, at least when we discussed it on this thread.
https://reviews.llvm.org/D155342#4511887
A fellow Linux kernel dev (who introduced the usage of
__attribute__((cleanup())) (and asm goto, coincidentally) to the kernel) agreed
(on IRC).
For now in clang, we produce a diagnostic since the behavior seems surprising.
If this gets changed in GCC, I'd be happy to modify clang to match that updated
behavior.
