- Create isolate specific resuable handles and use them in the hot lookup paths.

runtime/vm/handles.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_HANDLES_H_
 #define VM_HANDLES_H_
 
 #include "vm/allocation.h"
 #include "vm/flags.h"
 #include "vm/os.h"
@@ skipping 210 matching lines @@
   void ZapFreeScopedHandles();
 #endif
 
   HandlesBlock* zone_blocks_;  // List of zone handles.
   HandlesBlock first_scoped_block_;  // First block of scoped handles.
   HandlesBlock* scoped_blocks_;  // List of scoped handles.
 
   friend class HandleScope;
   friend class Dart;
   friend class ObjectStore;
+  friend class Isolate;
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(Handles);
 };
 
 
 static const int kVMHandleSizeInWords = 2;
 static const int kVMHandlesPerChunk = 64;
 static const int kOffsetOfRawPtr = kWordSize;
 class VMHandles : public Handles<kVMHandleSizeInWords,
                                  kVMHandlesPerChunk,
@@ skipping 90 matching lines @@
   explicit NoHandleScope(BaseIsolate* isolate) { }
   NoHandleScope() { }
   ~NoHandleScope() { }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(NoHandleScope);
 };
 #endif  // defined(DEBUG)
 
 // Macro to start a no handles scope in the code.
-#define NOHANDLESCOPE(isolate)                                                \
+#define NOHANDLESCOPE(isolate)                                                 \
     dart::NoHandleScope no_vm_internal_handles_scope_(isolate);
 
+
+// The class ReusableHandleScope is used in regions of the
+// virtual machine where isolate specific reusable handles are used.
+// This class asserts that we do not add code that will result in recursive
+// uses of reusable handles.
+// It is used as follows:
+// {
+//   REUSABLE_HANDLESCOPE(isolate);
+//   ....
+//   .....
+//   code that uses isolate specific reusable handles.
+//   ....
+// }
+#if defined(DEBUG)
+class ReusableHandleScope : public StackResource {
+ public:
+  explicit ReusableHandleScope(BaseIsolate* isolate);
+  ReusableHandleScope();
+  ~ReusableHandleScope();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ReusableHandleScope);
+};
+#else  // defined(DEBUG)
+class ReusableHandleScope : public ValueObject {
+ public:
+  explicit ReusableHandleScope(BaseIsolate* isolate) { }
+  ReusableHandleScope() { }
+  ~ReusableHandleScope() { }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ReusableHandleScope);
+};
+#endif  // defined(DEBUG)
+
+// Macro to start a no handles scope in the code.

[Ivan Posva, 2013/06/16 11:15:26]

Comment does not match code.

[siva, 2013/06/19 20:41:55]

Done.

+#define REUSABLE_HANDLESCOPE(isolate)                                          \
+    dart::ReusableHandleScope reusable_vm_internal_handles_scope_(isolate);
+
 }  // namespace dart
 
 #endif  // VM_HANDLES_H_