Parallel recompilation: fewer handle dereferences and tighter checks.

src/heap.h

 // Copyright 2012 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 1804 matching lines @@
 
   void CheckpointObjectStats();
 
   // We don't use a ScopedLock here since we want to lock the heap
   // only when FLAG_parallel_recompilation is true.
   class RelocationLock {
    public:
     explicit RelocationLock(Heap* heap) : heap_(heap) {
       if (FLAG_parallel_recompilation) {
         heap_->relocation_mutex_->Lock();
+#ifdef DEBUG
+        heap_->relocation_mutex_locked_ = true;
+#endif  // DEBUG
       }
     }
+
     ~RelocationLock() {
       if (FLAG_parallel_recompilation) {
+#ifdef DEBUG
+        heap_->relocation_mutex_locked_ = false;
+#endif  // DEBUG
         heap_->relocation_mutex_->Unlock();
       }
     }
 
+#ifdef DEBUG
+    static bool IsLocked(Heap* heap) {
+      return heap->relocation_mutex_locked_;
+    }
+#endif  // DEBUG
+
    private:
     Heap* heap_;
   };
 
  private:
   Heap();
 
   // This can be calculated directly from a pointer to the heap; however, it is
   // more expedient to get at the isolate directly from within Heap methods.
   Isolate* isolate_;
@@ skipping 454 matching lines @@
 
   ExternalStringTable external_string_table_;
 
   ErrorObjectList error_object_list_;
 
   VisitorDispatchTable<ScavengingCallback> scavenging_visitors_table_;
 
   MemoryChunk* chunks_queued_for_free_;
 
   Mutex* relocation_mutex_;
+#ifdef DEBUG
+  bool relocation_mutex_locked_;
+#endif  // DEBUG;
 
   friend class Factory;
   friend class GCTracer;
   friend class DisallowAllocationFailure;
   friend class AlwaysAllocateScope;
   friend class Page;
   friend class Isolate;
   friend class MarkCompactCollector;
   friend class MarkCompactMarkingVisitor;
   friend class MapCompact;
@@ skipping 686 matching lines @@
   AssertNoAllocation no_alloc;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_