Minimize malloc heap allocation on process startup.

src/isolate.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 58 matching lines @@
   if (thread_id == 0) {
     thread_id = AllocateThreadId();
     Thread::SetThreadLocalInt(Isolate::thread_id_key_, thread_id);
   }
   return thread_id;
 }
 
 
 ThreadLocalTop::ThreadLocalTop() {
   InitializeInternal();
+  // This flag may be set using v8::V8::IgnoreOutOfMemoryException()
+  // before an isolate is initialized. The initialize methods below do
+  // not touch it to preserve its value.
+  ignore_out_of_memory_ = false;
 }
 
 
 void ThreadLocalTop::InitializeInternal() {
   c_entry_fp_ = 0;
   handler_ = 0;
 #ifdef USE_SIMULATOR
   simulator_ = NULL;
 #endif
   js_entry_sp_ = NULL;
@@ skipping 286 matching lines @@
     thread_id_key_ = Thread::CreateThreadLocalKey();
     per_isolate_thread_data_key_ = Thread::CreateThreadLocalKey();
     thread_data_table_ = new Isolate::ThreadDataTable();
     default_isolate_ = new Isolate();
   }
   // Can't use SetIsolateThreadLocals(default_isolate_, NULL) here
   // becase a non-null thread data may be already set.
   if (Thread::GetThreadLocal(isolate_key_) == NULL) {
     Thread::SetThreadLocal(isolate_key_, default_isolate_);
   }
-  CHECK(default_isolate_->PreInit());
 }
 
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
 Debugger* Isolate::GetDefaultIsolateDebugger() {
   EnsureDefaultIsolate();
   return default_isolate_->debugger();
 }
 #endif
 
@@ skipping 972 matching lines @@
 Isolate::Isolate()
     : state_(UNINITIALIZED),
       entry_stack_(NULL),
       stack_trace_nesting_level_(0),
       incomplete_message_(NULL),
       preallocated_memory_thread_(NULL),
       preallocated_message_space_(NULL),
       bootstrapper_(NULL),
       runtime_profiler_(NULL),
       compilation_cache_(NULL),
-      counters_(new Counters()),
+      counters_(NULL),
       code_range_(NULL),
+      // Must be initialized early to allow v8::SetResourceConstraints calls.
       break_access_(OS::CreateMutex()),
-      logger_(new Logger()),
-      stats_table_(new StatsTable()),
+      debugger_initialized_(false),
+      // Must be initialized early to allow v8::Debug calls.
+      debugger_access_(OS::CreateMutex()),
+      logger_(NULL),
+      stats_table_(NULL),
       stub_cache_(NULL),
       deoptimizer_data_(NULL),
       capture_stack_trace_for_uncaught_exceptions_(false),
       stack_trace_for_uncaught_exceptions_frame_limit_(0),
       stack_trace_for_uncaught_exceptions_options_(StackTrace::kOverview),
       transcendental_cache_(NULL),
       memory_allocator_(NULL),
       keyed_lookup_cache_(NULL),
       context_slot_cache_(NULL),
       descriptor_lookup_cache_(NULL),
@@ skipping 110 matching lines @@
     CpuProfiler::TearDown();
     if (runtime_profiler_ != NULL) {
       runtime_profiler_->TearDown();
       delete runtime_profiler_;
       runtime_profiler_ = NULL;
     }
     heap_.TearDown();
     logger_->TearDown();
 
     // The default isolate is re-initializable due to legacy API.
-    state_ = PREINITIALIZED;
+    state_ = UNINITIALIZED;
   }
 }
 
 
 void Isolate::SetIsolateThreadLocals(Isolate* isolate,
                                      PerIsolateThreadData* data) {
   Thread::SetThreadLocal(isolate_key_, isolate);
   Thread::SetThreadLocal(per_isolate_thread_data_key_, data);
 }
 
@@ skipping 61 matching lines @@
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
   delete debugger_;
   debugger_ = NULL;
   delete debug_;
   debug_ = NULL;
 #endif
 }
 
 
-bool Isolate::PreInit() {
-  if (state_ != UNINITIALIZED) return true;
-
-  TRACE_ISOLATE(preinit);
-
-  ASSERT(Isolate::Current() == this);
-#ifdef ENABLE_DEBUGGER_SUPPORT
-  debug_ = new Debug(this);
-  debugger_ = new Debugger(this);
-#endif
-
-  memory_allocator_ = new MemoryAllocator();
-  memory_allocator_->isolate_ = this;
-  code_range_ = new CodeRange();
-  code_range_->isolate_ = this;
-
-  // Safe after setting Heap::isolate_, initializing StackGuard and
-  // ensuring that Isolate::Current() == this.
-  heap_.SetStackLimits();
-
-#ifdef DEBUG
-  DisallowAllocationFailure disallow_allocation_failure;
-#endif
-
-#define C(name) isolate_addresses_[Isolate::k_##name] =                        \
-    reinterpret_cast<Address>(name());
-  ISOLATE_ADDRESS_LIST(C)
-#undef C
-
-  string_tracker_ = new StringTracker();
-  string_tracker_->isolate_ = this;
-  compilation_cache_ = new CompilationCache(this);
-  transcendental_cache_ = new TranscendentalCache();
-  keyed_lookup_cache_ = new KeyedLookupCache();
-  context_slot_cache_ = new ContextSlotCache();
-  descriptor_lookup_cache_ = new DescriptorLookupCache();
-  unicode_cache_ = new UnicodeCache();
-  pc_to_code_cache_ = new PcToCodeCache(this);
-  write_input_buffer_ = new StringInputBuffer();
-  global_handles_ = new GlobalHandles(this);
-  bootstrapper_ = new Bootstrapper();
-  handle_scope_implementer_ = new HandleScopeImplementer(this);
-  stub_cache_ = new StubCache(this);
-  ast_sentinels_ = new AstSentinels();
-  regexp_stack_ = new RegExpStack();
-  regexp_stack_->isolate_ = this;
-
-  state_ = PREINITIALIZED;
-  return true;
-}
-
-
 void Isolate::InitializeThreadLocal() {
   thread_local_top_.isolate_ = this;
   thread_local_top_.Initialize();
   clear_pending_exception();
   clear_pending_message();
   clear_scheduled_exception();
 }
 
 
 void Isolate::PropagatePendingExceptionToExternalTryCatch() {
@@ skipping 16 matching lines @@
     ASSERT(!pending_exception()->IsFailure());
     try_catch_handler()->can_continue_ = true;
     try_catch_handler()->exception_ = pending_exception();
     if (!thread_local_top_.pending_message_obj_->IsTheHole()) {
       try_catch_handler()->message_ = thread_local_top_.pending_message_obj_;
     }
   }
 }
 
 
+void Isolate::InitializeLoggingAndCounters() {
+  if (logger_ == NULL) {
+    logger_ = new Logger;
+  }
+  if (counters_ == NULL) {
+    counters_ = new Counters;
+  }
+}
+
+
+void Isolate::InitializeDebugger() {
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  ScopedLock lock(debugger_access_);
+  if (NoBarrier_Load(&debugger_initialized_)) return;
+  InitializeLoggingAndCounters();
+  debug_ = new Debug(this);
+  debugger_ = new Debugger(this);
+  Release_Store(&debugger_initialized_, true);
+#endif
+}
+
+
 bool Isolate::Init(Deserializer* des) {
   ASSERT(state_ != INITIALIZED);
-
+  ASSERT(Isolate::Current() == this);
   TRACE_ISOLATE(init);
 
-  bool create_heap_objects = des == NULL;
-
 #ifdef DEBUG
   // The initialization process does not handle memory exhaustion.
   DisallowAllocationFailure disallow_allocation_failure;
 #endif
 
-  if (state_ == UNINITIALIZED && !PreInit()) return false;
+  InitializeLoggingAndCounters();
+
+  InitializeDebugger();
+
+  memory_allocator_ = new MemoryAllocator(this);
+  code_range_ = new CodeRange(this);
+
+  // Safe after setting Heap::isolate_, initializing StackGuard and
+  // ensuring that Isolate::Current() == this.
+  heap_.SetStackLimits();
+
+#define C(name) isolate_addresses_[Isolate::k_##name] =                        \
+    reinterpret_cast<Address>(name());
+  ISOLATE_ADDRESS_LIST(C)
+#undef C
+
+  string_tracker_ = new StringTracker();
+  string_tracker_->isolate_ = this;
+  compilation_cache_ = new CompilationCache(this);
+  transcendental_cache_ = new TranscendentalCache();
+  keyed_lookup_cache_ = new KeyedLookupCache();
+  context_slot_cache_ = new ContextSlotCache();
+  descriptor_lookup_cache_ = new DescriptorLookupCache();
+  unicode_cache_ = new UnicodeCache();
+  pc_to_code_cache_ = new PcToCodeCache(this);
+  write_input_buffer_ = new StringInputBuffer();
+  global_handles_ = new GlobalHandles(this);
+  bootstrapper_ = new Bootstrapper();
+  handle_scope_implementer_ = new HandleScopeImplementer(this);
+  stub_cache_ = new StubCache(this);
+  ast_sentinels_ = new AstSentinels();
+  regexp_stack_ = new RegExpStack();
+  regexp_stack_->isolate_ = this;
 
   // Enable logging before setting up the heap
   logger_->Setup();
 
   CpuProfiler::Setup();
   HeapProfiler::Setup();
 
   // Initialize other runtime facilities
 #if defined(USE_SIMULATOR)
 #if defined(V8_TARGET_ARCH_ARM) || defined(V8_TARGET_ARCH_MIPS)
   Simulator::Initialize(this);
 #endif
 #endif
 
   { // NOLINT
     // Ensure that the thread has a valid stack guard.  The v8::Locker object
     // will ensure this too, but we don't have to use lockers if we are only
     // using one thread.
     ExecutionAccess lock(this);
     stack_guard_.InitThread(lock);
   }
 
-  // Setup the object heap
+  // Setup the object heap.
+  const bool create_heap_objects = (des == NULL);
   ASSERT(!heap_.HasBeenSetup());
   if (!heap_.Setup(create_heap_objects)) {
     V8::SetFatalError();
     return false;
   }
 
   InitializeThreadLocal();
 
   bootstrapper_->Initialize(create_heap_objects);
   builtins_.Setup(create_heap_objects);
@@ skipping 39 matching lines @@
     HandleScope scope;
     LOG(this, LogCodeObjects());
     LOG(this, LogCompiledFunctions());
   }
 
   state_ = INITIALIZED;
   return true;
 }
 
 
+// Initialized lazily to allow early
+// v8::V8::SetAddHistogramSampleFunction calls.
+StatsTable* Isolate::stats_table() {
+  if (stats_table_ == NULL) {
+    stats_table_ = new StatsTable;
+  }
+  return stats_table_;
+}
+
+
 void Isolate::Enter() {
   Isolate* current_isolate = NULL;
   PerIsolateThreadData* current_data = CurrentPerIsolateThreadData();
   if (current_data != NULL) {
     current_isolate = current_data->isolate_;
     ASSERT(current_isolate != NULL);
     if (current_isolate == this) {
       ASSERT(Current() == this);
       ASSERT(entry_stack_ != NULL);
       ASSERT(entry_stack_->previous_thread_data == NULL ||
@@ skipping 19 matching lines @@
   ASSERT(data != NULL);
   ASSERT(data->isolate_ == this);
 
   EntryStackItem* item = new EntryStackItem(current_data,
                                             current_isolate,
                                             entry_stack_);
   entry_stack_ = item;
 
   SetIsolateThreadLocals(this, data);
 
-  CHECK(PreInit());
-
   // In case it's the first time some thread enters the isolate.
   set_thread_id(data->thread_id());
 }
 
 
 void Isolate::Exit() {
   ASSERT(entry_stack_ != NULL);
   ASSERT(entry_stack_->previous_thread_data == NULL ||
          entry_stack_->previous_thread_data->thread_id().Equals(
              ThreadId::Current()));
@@ skipping 19 matching lines @@
 
 #ifdef DEBUG
 #define ISOLATE_FIELD_OFFSET(type, name, ignored)                       \
 const intptr_t Isolate::name##_debug_offset_ = OFFSET_OF(Isolate, name##_);
 ISOLATE_INIT_LIST(ISOLATE_FIELD_OFFSET)
 ISOLATE_INIT_ARRAY_LIST(ISOLATE_FIELD_OFFSET)
 #undef ISOLATE_FIELD_OFFSET
 #endif
 
 } }  // namespace v8::internal