[compiler-rt] r253560 - [tsan] For OS X thread finalization, remove g_thread_finalize_key in favor of libpthread hooks

[Kuba Brecka via llvm-commits]

Author: kuba.brecka
Date: Thu Nov 19 06:06:20 2015
New Revision: 253560

URL: http://llvm.org/viewvc/llvm-project?rev=253560&view=rev
Log:
[tsan] For OS X thread finalization, remove g_thread_finalize_key in favor of libpthread hooks

On OS X, the thread finalization is fragile due to thread-local variables destruction order. I've seen cases where the we destroy the ThreadState too early and subsequent thread-local values' destructors call interceptors again. Let's replace the TLV-based thread finalization method with libpthread hooks. The notification PTHREAD_INTROSPECTION_THREAD_TERMINATE is called *after* all TLVs have been destroyed.

Differential Revision: http://reviews.llvm.org/D14777


Modified:
    compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc
    compiler-rt/trunk/lib/tsan/rtl/tsan_platform_mac.cc

Modified: compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc?rev=253560&r1=253559&r2=253560&view=diff
==============================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc (original)
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc Thu Nov 19 06:06:20 2015
@@ -233,7 +233,9 @@ static ThreadSignalContext *SigCtx(Threa
   return ctx;
 }
 
+#if !SANITIZER_MAC
 static unsigned g_thread_finalize_key;
+#endif
 
 ScopedInterceptor::ScopedInterceptor(ThreadState *thr, const char *fname,
                                      uptr pc)
@@ -825,6 +827,7 @@ void DestroyThreadState() {
 }
 }  // namespace __tsan
 
+#if !SANITIZER_MAC
 static void thread_finalize(void *v) {
   uptr iter = (uptr)v;
   if (iter > 1) {
@@ -836,6 +839,7 @@ static void thread_finalize(void *v) {
   }
   DestroyThreadState();
 }
+#endif
 
 
 struct ThreadParam {
@@ -853,6 +857,7 @@ extern "C" void *__tsan_thread_start_fun
     ThreadState *thr = cur_thread();
     // Thread-local state is not initialized yet.
     ScopedIgnoreInterceptors ignore;
+#if !SANITIZER_MAC
     ThreadIgnoreBegin(thr, 0);
     if (pthread_setspecific(g_thread_finalize_key,
                             (void *)GetPthreadDestructorIterations())) {
@@ -860,6 +865,7 @@ extern "C" void *__tsan_thread_start_fun
       Die();
     }
     ThreadIgnoreEnd(thr, 0);
+#endif
     while ((tid = atomic_load(&p->tid, memory_order_acquire)) == 0)
       internal_sched_yield();
     ThreadStart(thr, tid, GetTid());
@@ -2640,10 +2646,12 @@ void InitializeInterceptors() {
     Die();
   }
 
+#if !SANITIZER_MAC
   if (pthread_key_create(&g_thread_finalize_key, &thread_finalize)) {
     Printf("ThreadSanitizer: failed to create thread key\n");
     Die();
   }
+#endif
 
   FdInit();
 }

Modified: compiler-rt/trunk/lib/tsan/rtl/tsan_platform_mac.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_platform_mac.cc?rev=253560&r1=253559&r2=253560&view=diff
==============================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_platform_mac.cc (original)
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_platform_mac.cc Thu Nov 19 06:06:20 2015
@@ -124,7 +124,7 @@ typedef void (*pthread_introspection_hoo
 extern "C" pthread_introspection_hook_t pthread_introspection_hook_install(
     pthread_introspection_hook_t hook);
 static const uptr PTHREAD_INTROSPECTION_THREAD_CREATE = 1;
-static const uptr PTHREAD_INTROSPECTION_THREAD_DESTROY = 4;
+static const uptr PTHREAD_INTROSPECTION_THREAD_TERMINATE = 3;
 static pthread_introspection_hook_t prev_pthread_introspection_hook;
 static void my_pthread_introspection_hook(unsigned int event, pthread_t thread,
                                           void *addr, size_t size) {
@@ -137,10 +137,12 @@ static void my_pthread_introspection_hoo
       ThreadState *thr = cur_thread();
       ThreadStart(thr, tid, GetTid());
     }
-  } else if (event == PTHREAD_INTROSPECTION_THREAD_DESTROY) {
-    ThreadState *thr = cur_thread();
-    if (thr->tctx && thr->tctx->parent_tid == kInvalidTid) {
-      DestroyThreadState();
+  } else if (event == PTHREAD_INTROSPECTION_THREAD_TERMINATE) {
+    if (thread == pthread_self()) {
+      ThreadState *thr = cur_thread();
+      if (thr->tctx) {
+        DestroyThreadState();
+      }
     }
   }