[tsan] Add comments for the bool argument of ThreadIgnoreBegin/ThreadIgnoreSyncBegin, NFC.

compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc

if (!thr_->ignore_interceptors) {
     ProcessPendingSignals(thr_);
     FuncExit(thr_);
     CheckNoLocks(thr_);
   }
 }
 
 void ScopedInterceptor::EnableIgnores() {
   if (ignoring_) {
-    ThreadIgnoreBegin(thr_, pc_, false);
+    ThreadIgnoreBegin(thr_, pc_, /*save_stack=*/false);
     if (flags()->ignore_noninstrumented_modules) thr_->suppress_reports++;
     if (in_ignored_lib_) {
       DCHECK(!thr_->in_ignored_lib);
       thr_->in_ignored_lib = true;
     }
   }
 }
 

compiler-rt/trunk/lib/tsan/rtl/tsan_interface_ann.cc

 void __tsan_mutex_pre_lock(void *m, unsigned flagz) {
   SCOPED_ANNOTATION(__tsan_mutex_pre_lock);
   if (!(flagz & MutexFlagTryLock)) {
     if (flagz & MutexFlagReadLock)
       MutexPreReadLock(thr, pc, (uptr)m);
     else
       MutexPreLock(thr, pc, (uptr)m);
   }
-  ThreadIgnoreBegin(thr, pc, false);
-  ThreadIgnoreSyncBegin(thr, pc, false);
+  ThreadIgnoreBegin(thr, pc, /*save_stack=*/false);
+  ThreadIgnoreSyncBegin(thr, pc, /*save_stack=*/false);
 }
 
 INTERFACE_ATTRIBUTE
 void __tsan_mutex_post_lock(void *m, unsigned flagz, int rec) {
   SCOPED_ANNOTATION(__tsan_mutex_post_lock);
   ThreadIgnoreSyncEnd(thr, pc);
   ThreadIgnoreEnd(thr, pc);
   if (!(flagz & MutexFlagTryLockFailed)) {
int __tsan_mutex_pre_unlock(void *m, unsigned flagz) {
   SCOPED_ANNOTATION_RET(__tsan_mutex_pre_unlock, 0);
   int ret = 0;
   if (flagz & MutexFlagReadLock) {
     CHECK(!(flagz & MutexFlagRecursiveUnlock));
     MutexReadUnlock(thr, pc, (uptr)m);
   } else {
     ret = MutexUnlock(thr, pc, (uptr)m, flagz);
   }
-  ThreadIgnoreBegin(thr, pc, false);
-  ThreadIgnoreSyncBegin(thr, pc, false);
+  ThreadIgnoreBegin(thr, pc, /*save_stack=*/false);
+  ThreadIgnoreSyncBegin(thr, pc, /*save_stack=*/false);
   return ret;
 }
 
 INTERFACE_ATTRIBUTE
 void __tsan_mutex_post_unlock(void *m, unsigned flagz) {
   SCOPED_ANNOTATION(__tsan_mutex_post_unlock);
   ThreadIgnoreSyncEnd(thr, pc);
   ThreadIgnoreEnd(thr, pc);
 }
 
 INTERFACE_ATTRIBUTE
 void __tsan_mutex_pre_signal(void *addr, unsigned flagz) {
   SCOPED_ANNOTATION(__tsan_mutex_pre_signal);
-  ThreadIgnoreBegin(thr, pc, false);
-  ThreadIgnoreSyncBegin(thr, pc, false);
+  ThreadIgnoreBegin(thr, pc, /*save_stack=*/false);
+  ThreadIgnoreSyncBegin(thr, pc, /*save_stack=*/false);
 }
 
 INTERFACE_ATTRIBUTE
 void __tsan_mutex_post_signal(void *addr, unsigned flagz) {
   SCOPED_ANNOTATION(__tsan_mutex_post_signal);
   ThreadIgnoreSyncEnd(thr, pc);
   ThreadIgnoreEnd(thr, pc);
 }
 
 INTERFACE_ATTRIBUTE
 void __tsan_mutex_pre_divert(void *addr, unsigned flagz) {
   SCOPED_ANNOTATION(__tsan_mutex_pre_divert);
   // Exit from ignore region started in __tsan_mutex_pre_lock/unlock/signal.
   ThreadIgnoreSyncEnd(thr, pc);
   ThreadIgnoreEnd(thr, pc);
 }
 
 INTERFACE_ATTRIBUTE
 void __tsan_mutex_post_divert(void *addr, unsigned flagz) {
   SCOPED_ANNOTATION(__tsan_mutex_post_divert);
-  ThreadIgnoreBegin(thr, pc, false);
-  ThreadIgnoreSyncBegin(thr, pc, false);
+  ThreadIgnoreBegin(thr, pc, /*save_stack=*/false);
+  ThreadIgnoreSyncBegin(thr, pc, /*save_stack=*/false);
 }
 }  // extern "C"