Introduce SynchronizedScope to allow heap access from compiler thread.

src/execution.h

 // 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 27 matching lines @@
 enum InterruptFlag {
   INTERRUPT = 1 << 0,
   DEBUGBREAK = 1 << 1,
   DEBUGCOMMAND = 1 << 2,
   PREEMPT = 1 << 3,
   TERMINATE = 1 << 4,
   GC_REQUEST = 1 << 5,
   FULL_DEOPT = 1 << 6,
   INSTALL_CODE = 1 << 7,
   API_INTERRUPT = 1 << 8,
-  DEOPT_MARKED_ALLOCATION_SITES = 1 << 9
+  DEOPT_MARKED_ALLOCATION_SITES = 1 << 9,
+  COMPILER_SYNC = 1 << 10
 };
 
 
 class Isolate;
 
 
 class Execution : public AllStatic {
  public:
   // Call a function, the caller supplies a receiver and an array
   // of arguments. Arguments are Object* type. After function returns,
@@ skipping 155 matching lines @@
 #ifdef ENABLE_DEBUGGER_SUPPORT
   bool IsDebugBreak();
   void DebugBreak();
   bool IsDebugCommand();
   void DebugCommand();
 #endif
   bool IsGCRequest();
   void RequestGC();
   bool IsInstallCodeRequest();
   void RequestInstallCode();
+  bool IsCompilerSyncRequest();
+  void RequestCompilerSync();
   bool IsFullDeopt();
   void FullDeopt();
   bool IsDeoptMarkedAllocationSites();
   void DeoptMarkedAllocationSites();
   void Continue(InterruptFlag after_what);
 
   void RequestInterrupt(InterruptCallback callback, void* data);
   void ClearInterrupt();
   bool IsAPIInterrupt();
   void InvokeInterruptCallback();
@@ skipping 97 matching lines @@
   friend class StackLimitCheck;
   friend class PostponeInterruptsScope;
 
   DISALLOW_COPY_AND_ASSIGN(StackGuard);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_EXECUTION_H_