Instrument callers of Semaphore::Signal to help with investigation of

src/base/platform/semaphore.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/platform/semaphore.h"
 
 #if V8_OS_MACOSX
 #include <mach/mach_init.h>
 #include <mach/task.h>
 #endif
@@ skipping 16 matching lines @@
   USE(result);
 }
 
 
 Semaphore::~Semaphore() {
   kern_return_t result = semaphore_destroy(mach_task_self(), native_handle_);
   DCHECK_EQ(KERN_SUCCESS, result);
   USE(result);
 }
 
-
-void Semaphore::Signal() {
+void Semaphore::Signal(const char* caller) {
   kern_return_t result = semaphore_signal(native_handle_);
   DCHECK_EQ(KERN_SUCCESS, result);
   USE(result);
+  USE(caller);
 }
 
 
 void Semaphore::Wait() {
   while (true) {
     kern_return_t result = semaphore_wait(native_handle_);
     if (result == KERN_SUCCESS) return;  // Semaphore was signalled.
     DCHECK_EQ(KERN_ABORTED, result);
   }
 }
@@ skipping 45 matching lines @@
   USE(result);
 }
 
 
 Semaphore::~Semaphore() {
   int result = sem_destroy(&native_handle_);
   DCHECK_EQ(0, result);
   USE(result);
 }
 
-
-void Semaphore::Signal() {
+void Semaphore::Signal(const char* caller) {
   int result = sem_post(&native_handle_);
   if (result != 0) {
-    V8_Fatal(__FILE__, __LINE__, "Semaphore signal failure: %d\n", errno);
+    V8_Fatal(__FILE__, __LINE__,
+             "Semaphore signal failure: %d called by '%s'\n", errno, caller);
   }
 }
 
 
 void Semaphore::Wait() {
   while (true) {
     int result = sem_wait(&native_handle_);
     if (result == 0) return;  // Semaphore was signalled.
     // Signal caused spurious wakeup.
     DCHECK_EQ(-1, result);
@@ skipping 48 matching lines @@
   DCHECK(native_handle_ != NULL);
 }
 
 
 Semaphore::~Semaphore() {
   BOOL result = CloseHandle(native_handle_);
   DCHECK(result);
   USE(result);
 }
 
-
-void Semaphore::Signal() {
+void Semaphore::Signal(const char* caller) {
   LONG dummy;
   BOOL result = ReleaseSemaphore(native_handle_, 1, &dummy);
   DCHECK(result);
   USE(result);
+  USE(caller);
 }
 
 
 void Semaphore::Wait() {
   DWORD result = WaitForSingleObject(native_handle_, INFINITE);
   DCHECK(result == WAIT_OBJECT_0);
   USE(result);
 }
 
 
@@ skipping 18 matching lines @@
       DCHECK(result == WAIT_OBJECT_0);
       return true;
     }
   }
 }
 
 #endif  // V8_OS_MACOSX
 
 }  // namespace base
 }  // namespace v8