Parallel recompilation: fewer handle dereferences and tighter checks.

src/handles.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 46 matching lines @@
     S* b = NULL;
     a = b;  // Fake assignment to enforce type checks.
     USE(a);
 #endif
     location_ = reinterpret_cast<T**>(handle.location_);
   }
 
   INLINE(T* operator ->() const) { return operator*(); }
 
   // Check if this handle refers to the exact same object as the other handle.
-  bool is_identical_to(const Handle<T> other) const {
-    return *location_ == *other.location_;
-  }
+  INLINE(bool is_identical_to(const Handle<T> other) const);
 
   // Provides the C++ dereference operator.
   INLINE(T* operator*() const);
 
   // Returns the address to where the raw pointer is stored.
   INLINE(T** location() const);
 
   template <class S> static Handle<T> cast(Handle<S> that) {
     T::cast(*that);
     return Handle<T>(reinterpret_cast<T**>(that.location()));
@@ skipping 254 matching lines @@
   explicit inline NoHandleAllocation(Isolate* isolate);
   inline ~NoHandleAllocation();
  private:
   Isolate* isolate_;
   int level_;
   bool active_;
 #endif
 };
 
 
-class NoHandleDereference BASE_EMBEDDED {
+class HandleDereferenceGuard BASE_EMBEDDED {
  public:
+  enum State { ALLOW, DISALLOW };
 #ifndef DEBUG
-  explicit NoHandleDereference(Isolate* isolate) {}
-  ~NoHandleDereference() {}
+  HandleDereferenceGuard(Isolate* isolate, State state) { }
+  ~HandleDereferenceGuard() { }
 #else
-  explicit inline NoHandleDereference(Isolate* isolate);
-  inline ~NoHandleDereference();
+  inline HandleDereferenceGuard(Isolate* isolate,  State state);
+  inline ~HandleDereferenceGuard();
  private:
   Isolate* isolate_;
   bool old_state_;
-#endif
-};
-
-
-class AllowHandleDereference BASE_EMBEDDED {
- public:
-#ifndef DEBUG
-  explicit AllowHandleDereference(Isolate* isolate) {}
-  ~AllowHandleDereference() {}
-#else
-  explicit inline AllowHandleDereference(Isolate* isolate);
-  inline ~AllowHandleDereference();
- private:
-  Isolate* isolate_;
-  bool old_state_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HANDLES_H_