tsan: fix tls_race3 test on darwin

[dvyukov]

Summary

Darwin also needs to use __tsan_tls_initialization
to pass the test.

[saghir]

Hi,

This change seems to be causing issues with Power PC buildbots. One such bot is https://lab.llvm.org/buildbot/#/builders/52/builds/10906. Can you please take a look to fix/revert the change? If there is anything I could do to help investigate, please let me know.

Thanks!

[nemanjai]

In D110631#3028852, @saghir wrote:

Hi,

This change seems to be causing issues with Power PC buildbots. One such bot is https://lab.llvm.org/buildbot/#/builders/52/builds/10906. Can you please take a look to fix/revert the change? If there is anything I could do to help investigate, please let me know.

Thanks!

I think that if we pull this, we'll just break the test case that this fixes. Please advise how we should proceed with this @dvyukov

[nemanjai]

@saghir Since the bots have been failing for a few days now and there is no response, please try to figure out what commit this is a fix for so we can revert all related commits until we can get to the bottom of this problem.

compiler-rt/lib/tsan/rtl/tsan_platform_mac.cpp

uptr ExtractLongJmpSp(uptr *env) {
   uptr mangled_sp = env[LONG_JMP_SP_ENV_SLOT];
   uptr sp = mangled_sp ^ longjmp_xor_key;
   sp = (uptr)ptrauth_auth_data((void *)sp, ptrauth_key_asdb,
                                ptrauth_string_discriminator("sp"));
   return sp;
 }
 
 #if !SANITIZER_GO
+extern "C" void __tsan_tls_initialization() {}
+
 void ImitateTlsWrite(ThreadState *thr, uptr tls_addr, uptr tls_size) {
   // The pointer to the ThreadState object is stored in the shadow memory
   // of the tls.
   uptr tls_end = tls_addr + tls_size;
   uptr thread_identity = (uptr)pthread_self();
+  const uptr pc = StackTrace::GetNextInstructionPc(
+      reinterpret_cast<uptr>(__tsan_tls_initialization));
   if (thread_identity == main_thread_identity) {
-    MemoryRangeImitateWrite(thr, /*pc=*/2, tls_addr, tls_size);
+    MemoryRangeImitateWrite(thr, pc, tls_addr, tls_size);
   } else {
     uptr thr_state_start = thread_identity;
     uptr thr_state_end = thr_state_start + sizeof(uptr);
     CHECK_GE(thr_state_start, tls_addr);
     CHECK_LE(thr_state_start, tls_addr + tls_size);
     CHECK_GE(thr_state_end, tls_addr);
     CHECK_LE(thr_state_end, tls_addr + tls_size);
-    MemoryRangeImitateWrite(thr, /*pc=*/2, tls_addr,
-                            thr_state_start - tls_addr);
-    MemoryRangeImitateWrite(thr, /*pc=*/2, thr_state_end,
-                            tls_end - thr_state_end);
+    MemoryRangeImitateWrite(thr, pc, tls_addr, thr_state_start - tls_addr);
+    MemoryRangeImitateWrite(thr, pc, thr_state_end, tls_end - thr_state_end);
   }
 }
 #endif
 
 #if !SANITIZER_GO
 // Note: this function runs with async signals enabled,
 // so it must not touch any tsan state.
 int call_pthread_cancel_with_cleanup(int (*fn)(void *arg),