tsan: support linker init flag in __tsan_mutex_destroy

For a linker init mutex with lazy flag setup
(no __tsan_mutex_create call), it is possible that
no lock/unlock happened before the destroy call.
Then when destroy runs we still don't know that
it is a linker init mutex and will emulate a memory write.
This in turn can lead to false positives as the mutex
is in fact linker initialized.

Support linker init flag in destroy annotation to resolve this.



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@301795 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 6 insertions, 5 deletions

diff --git a/include/sanitizer/tsan_interface.h b/include/sanitizer/tsan_interface.h
index 45e54f758..a0c702638 100644
--- a/include/sanitizer/tsan_interface.h
+++ b/include/sanitizer/tsan_interface.h
@@ -68,7 +68,8 @@ const unsigned __tsan_mutex_recursive_unlock = 1 << 7;
 void __tsan_mutex_create(void *addr, unsigned flags);
 
 // Annotate destruction of a mutex.
-// Supported flags: none.
+// Supported flags:
+//   - __tsan_mutex_linker_init
 void __tsan_mutex_destroy(void *addr, unsigned flags);
 
 // Annotate start of lock operation.
diff --git a/lib/tsan/rtl/tsan_interface_ann.cc b/lib/tsan/rtl/tsan_interface_ann.cc
index 810c84025..45ec45bbd 100644
--- a/lib/tsan/rtl/tsan_interface_ann.cc
+++ b/lib/tsan/rtl/tsan_interface_ann.cc
@@ -471,7 +471,7 @@ void __tsan_mutex_create(void *m, unsigned flagz) {
 INTERFACE_ATTRIBUTE
 void __tsan_mutex_destroy(void *m, unsigned flagz) {
   SCOPED_ANNOTATION(__tsan_mutex_destroy);
-  MutexDestroy(thr, pc, (uptr)m);
+  MutexDestroy(thr, pc, (uptr)m, flagz);
 }
 
 INTERFACE_ATTRIBUTE
diff --git a/lib/tsan/rtl/tsan_rtl.h b/lib/tsan/rtl/tsan_rtl.h
index cc60eb6db..8bf1c191a 100644
--- a/lib/tsan/rtl/tsan_rtl.h
+++ b/lib/tsan/rtl/tsan_rtl.h
@@ -763,7 +763,7 @@ void ProcUnwire(Processor *proc, ThreadState *thr);
 // Note: the parameter is called flagz, because flags is already taken
 // by the global function that returns flags.
 void MutexCreate(ThreadState *thr, uptr pc, uptr addr, u32 flagz = 0);
-void MutexDestroy(ThreadState *thr, uptr pc, uptr addr);
+void MutexDestroy(ThreadState *thr, uptr pc, uptr addr, u32 flagz = 0);
 void MutexPreLock(ThreadState *thr, uptr pc, uptr addr, u32 flagz = 0);
 void MutexPostLock(ThreadState *thr, uptr pc, uptr addr, u32 flagz = 0,
     int rec = 1);
diff --git a/lib/tsan/rtl/tsan_rtl_mutex.cc b/lib/tsan/rtl/tsan_rtl_mutex.cc
index 086b28927..54938f37e 100644
--- a/lib/tsan/rtl/tsan_rtl_mutex.cc
+++ b/lib/tsan/rtl/tsan_rtl_mutex.cc
@@ -78,13 +78,13 @@ void MutexCreate(ThreadState *thr, uptr pc, uptr addr, u32 flagz) {
   s->mtx.Unlock();
 }
 
-void MutexDestroy(ThreadState *thr, uptr pc, uptr addr) {
+void MutexDestroy(ThreadState *thr, uptr pc, uptr addr, u32 flagz) {
   DPrintf("#%d: MutexDestroy %zx\n", thr->tid, addr);
   StatInc(thr, StatMutexDestroy);
   SyncVar *s = ctx->metamap.GetIfExistsAndLock(addr, true);
   if (s == 0)
     return;
-  if (s->IsFlagSet(MutexFlagLinkerInit)) {
+  if ((flagz & MutexFlagLinkerInit) || s->IsFlagSet(MutexFlagLinkerInit)) {
     // Destroy is no-op for linker-initialized mutexes.
     s->mtx.Unlock();
     return;