Simplify implementation of Mutex.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index bcd48945f2816b95b7c542cc9477b37e99dbe40c..cbb12256fe530268bbeda895a15951593d20410e 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -343,7 +343,7 @@ Thread::LocalStorageKey Isolate::per_isolate_thread_data_key_;
 #ifdef DEBUG
 Thread::LocalStorageKey PerThreadAssertScopeBase::thread_local_key;
 #endif  // DEBUG
-Mutex* Isolate::process_wide_mutex_ = OS::CreateMutex();
+Mutex Isolate::process_wide_mutex_;
 Isolate::ThreadDataTable* Isolate::thread_data_table_ = NULL;
 Atomic32 Isolate::isolate_counter_ = 0;
 
@@ -352,7 +352,7 @@ Isolate::PerIsolateThreadData* Isolate::AllocatePerIsolateThreadData(
   ASSERT(!thread_id.Equals(ThreadId::Invalid()));
   PerIsolateThreadData* per_thread = new PerIsolateThreadData(this, thread_id);
   {
-    ScopedLock lock(process_wide_mutex_);
+    ScopedLock lock(&process_wide_mutex_);
     ASSERT(thread_data_table_->Lookup(this, thread_id) == NULL);
     thread_data_table_->Insert(per_thread);
     ASSERT(thread_data_table_->Lookup(this, thread_id) == per_thread);
@@ -366,11 +366,11 @@ Isolate::PerIsolateThreadData*
   ThreadId thread_id = ThreadId::Current();
   PerIsolateThreadData* per_thread = NULL;
   {
-    ScopedLock lock(process_wide_mutex_);
+    ScopedLock lock(&process_wide_mutex_);
     per_thread = thread_data_table_->Lookup(this, thread_id);
-    if (per_thread == NULL) {
-      per_thread = AllocatePerIsolateThreadData(thread_id);
-    }
+  }
+  if (per_thread == NULL) {
+    per_thread = AllocatePerIsolateThreadData(thread_id);

[Sven Panne, 2013/07/30 15:09:56]

Why is it OK to move this outside the ScopedLock?

[Benedikt Meurer, 2013/07/30 16:50:52]

Because AllocatePerIsolateThreadData() acquires the process_wide_mutex_ prior to
inserting the new data into the thread_data_table_.

   }
   return per_thread;
 }
@@ -386,7 +386,7 @@ Isolate::PerIsolateThreadData* Isolate::FindPerThreadDataForThread(
     ThreadId thread_id) {
   PerIsolateThreadData* per_thread = NULL;
   {
-    ScopedLock lock(process_wide_mutex_);
+    ScopedLock lock(&process_wide_mutex_);
     per_thread = thread_data_table_->Lookup(this, thread_id);
   }
   return per_thread;
@@ -394,7 +394,7 @@ Isolate::PerIsolateThreadData* Isolate::FindPerThreadDataForThread(
 
 
 void Isolate::EnsureDefaultIsolate() {
-  ScopedLock lock(process_wide_mutex_);
+  ScopedLock lock(&process_wide_mutex_);
   if (default_isolate_ == NULL) {
     isolate_key_ = Thread::CreateThreadLocalKey();
     thread_id_key_ = Thread::CreateThreadLocalKey();
@@ -1749,10 +1749,8 @@ Isolate::Isolate()
       counters_(NULL),
       code_range_(NULL),
       // Must be initialized early to allow v8::SetResourceConstraints calls.
-      break_access_(OS::CreateMutex()),
       debugger_initialized_(false),
       // Must be initialized early to allow v8::Debug calls.
-      debugger_access_(OS::CreateMutex()),
       logger_(NULL),
       stats_table_(NULL),
       stub_cache_(NULL),
@@ -1853,7 +1851,7 @@ void Isolate::TearDown() {
 
   Deinit();
 
-  { ScopedLock lock(process_wide_mutex_);
+  { ScopedLock lock(&process_wide_mutex_);
     thread_data_table_->RemoveAllThreads(this);
   }
 
@@ -2024,10 +2022,6 @@ Isolate::~Isolate() {
 
   delete handle_scope_implementer_;
   handle_scope_implementer_ = NULL;
-  delete break_access_;
-  break_access_ = NULL;
-  delete debugger_access_;
-  debugger_access_ = NULL;
 
   delete compilation_cache_;
   compilation_cache_ = NULL;
@@ -2127,7 +2121,7 @@ void Isolate::InitializeLoggingAndCounters() {
 
 void Isolate::InitializeDebugger() {
 #ifdef ENABLE_DEBUGGER_SUPPORT
-  ScopedLock lock(debugger_access_);
+  ScopedLock lock(&debugger_access_);
   if (NoBarrier_Load(&debugger_initialized_)) return;
   InitializeLoggingAndCounters();
   debug_ = new Debug(this);