[Bug gold/20805] New: gcc's ThreadSanitizer broken by gold

[markus at trippelsdorf dot de]

https://sourceware.org/bugzilla/show_bug.cgi?id=20805

            Bug ID: 20805
           Summary: gcc's ThreadSanitizer broken by gold
           Product: binutils
           Version: 2.28 (HEAD)
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: gold
          Assignee: ccoutant at gmail dot com
          Reporter: markus at trippelsdorf dot de
                CC: ian at airs dot com
  Target Milestone: ---

Created attachment 9624
  --> https://sourceware.org/bugzilla/attachment.cgi?id=9624&action=edit
testcase

When gcc's ThreadSanitizer is linked with gold it crashes all instrumented
binaries because of calls to __tls_get_addr.

However ThreadSanitizer uses the initial-exec tls model:

__attribute__((tls_model("initial-exec")))                                      
extern THREADLOCAL char cur_thread_placeholder[];                               
INLINE ThreadState *cur_thread() {                                              
  return reinterpret_cast<ThreadState *>(&cur_thread_placeholder);              
} 

So no __tls_get_addr calls should be emitted.

For the attached testcase:

address@hidden libsanitizer % gcc -fuse-ld=bfd -shared tsan_interceptors.o
address@hidden libsanitizer % objdump -dS ./a.out | grep address@hidden
address@hidden libsanitizer % gcc -fuse-ld=gold -shared tsan_interceptors.o
address@hidden libsanitizer % objdump -dS ./a.out | grep address@hidden | wc -l
779

Also see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78294

-- 
You are receiving this mail because:
You are on the CC list for the bug.