d8: Leak context_mutex_ so it will never be destroyed while locked

Calling quit() from d8 will call exit(), which will run static destructors. If
context_mutex_ is statically allocated, pthread_mutex_destroy will be called.

When running d8 in "isolates" mode, another thread may be running. If it calls
CreateEvaluationContext, it will lock the context_mutex_. If the mutex is
destroyed while it is locked, it will return an error.

This CL changes the Mutex to a LazyMutex, which will leak instead of being
destroyed.

BUG=v8:4279
R=jarin@chromium.org
R=machenbach@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/1240553003

Cr-Commit-Position: refs/heads/master@{#29709}

src/d8.cc

@@ -202,11 +202,11 @@ CounterMap* Shell::counter_map_;
 base::OS::MemoryMappedFile* Shell::counters_file_ = NULL;
 CounterCollection Shell::local_counters_;
 CounterCollection* Shell::counters_ = &local_counters_;
-base::Mutex Shell::context_mutex_;
+base::LazyMutex Shell::context_mutex_;
 const base::TimeTicks Shell::kInitialTicks =
     base::TimeTicks::HighResolutionNow();
 Persistent<Context> Shell::utility_context_;
-base::Mutex Shell::workers_mutex_;
+base::LazyMutex Shell::workers_mutex_;
 bool Shell::allow_new_workers_ = true;
 i::List<Worker*> Shell::workers_;
 i::List<SharedArrayBuffer::Contents> Shell::externalized_shared_contents_;
@@ -699,7 +699,7 @@ void Shell::WorkerNew(const v8::FunctionCallbackInfo<v8::Value>& args) {
   }
 
   {
-    base::LockGuard<base::Mutex> lock_guard(&workers_mutex_);
+    base::LockGuard<base::Mutex> lock_guard(workers_mutex_.Pointer());
     if (!allow_new_workers_) return;
 
     Worker* worker = new Worker;
@@ -1203,7 +1203,7 @@ void Shell::InitializeDebugger(Isolate* isolate) {
 Local<Context> Shell::CreateEvaluationContext(Isolate* isolate) {
 #ifndef V8_SHARED
   // This needs to be a critical section since this is not thread-safe
-  base::LockGuard<base::Mutex> lock_guard(&context_mutex_);
+  base::LockGuard<base::Mutex> lock_guard(context_mutex_.Pointer());
 #endif  // !V8_SHARED
   // Initialize the global objects
   Handle<ObjectTemplate> global_template = CreateGlobalTemplate(isolate);
@@ -2252,7 +2252,7 @@ void Shell::CleanupWorkers() {
   // create a new Worker, it would deadlock.
   i::List<Worker*> workers_copy;
   {
-    base::LockGuard<base::Mutex> lock_guard(&workers_mutex_);
+    base::LockGuard<base::Mutex> lock_guard(workers_mutex_.Pointer());
     allow_new_workers_ = false;
     workers_copy.AddAll(workers_);
     workers_.Clear();
@@ -2266,7 +2266,7 @@ void Shell::CleanupWorkers() {
 
   // Now that all workers are terminated, we can re-enable Worker creation.
   {
-    base::LockGuard<base::Mutex> lock_guard(&workers_mutex_);
+    base::LockGuard<base::Mutex> lock_guard(workers_mutex_.Pointer());
     allow_new_workers_ = true;
   }
 

src/d8.h

@@ -481,10 +481,10 @@ class Shell : public i::AllStatic {
   static CounterCollection local_counters_;
   static CounterCollection* counters_;
   static base::OS::MemoryMappedFile* counters_file_;
-  static base::Mutex context_mutex_;
+  static base::LazyMutex context_mutex_;
   static const base::TimeTicks kInitialTicks;
 
-  static base::Mutex workers_mutex_;
+  static base::LazyMutex workers_mutex_;
   static bool allow_new_workers_;
   static i::List<Worker*> workers_;
   static i::List<SharedArrayBuffer::Contents> externalized_shared_contents_;