https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68178
Bug ID: 68178
Summary: [arm] Relative address expressions bind at as-time,
even if symbol is weak
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: bugdal at aerifal dot cx
Target Milestone: ---
This bug is almost identical to #66609 for [sh], except the conditions needed
to trigger it are slightly different. Minimal test case (compile with -fPIC; -O
level does not matter):
__attribute__((__weak__,__visibility__("hidden"))) void foo()
{
}
void *bar()
{
return (void *)foo;
}
The expected output should have a relocation for foo, since the weak definition
is replaceable by a strong definition from another TU. The actual output has a
PC-relative constant pointing to the weak definition.
This bug seriously broke musl libc's pthread_cancel.c, where the weak version
of the symbol used for updating PC upon cancellation has the wrong contract for
stack state, and the strong version from arm-specific asm needs to be used.
I still question whether this issue should be fixed on the binutils side for
all targets; see: https://sourceware.org/bugzilla/show_bug.cgi?id=18561
