Optimizing HandleScope. Also fixed HandleScope destruction when API getter th...

src/handles.cc

 // Copyright 2009 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 26 matching lines @@
 #include "global-handles.h"
 #include "natives.h"
 #include "runtime.h"
 #include "stub-cache.h"
 
 namespace v8 {
 namespace internal {
 
 
 v8::ImplementationUtilities::HandleScopeData HandleScope::current_ =
-    { -1, NULL, NULL };
+    { NULL, NULL, 0 };
 
 
 int HandleScope::NumberOfHandles() {
   int n = HandleScopeImplementer::instance()->blocks()->length();
   if (n == 0) return 0;
   return ((n - 1) * kHandleBlockSize) + static_cast<int>(
       (current_.next - HandleScopeImplementer::instance()->blocks()->last()));
 }
 
 
 Object** HandleScope::Extend() {
   Object** result = current_.next;
 
   ASSERT(result == current_.limit);
   // Make sure there's at least one scope on the stack and that the
   // top of the scope stack isn't a barrier.
-  if (current_.extensions < 0) {
+  if (current_.level == 0) {
     Utils::ReportApiFailure("v8::HandleScope::CreateHandle()",
                             "Cannot create a handle without a HandleScope");
     return NULL;
   }
   HandleScopeImplementer* impl = HandleScopeImplementer::instance();
   // If there's more room in the last block, we use that. This is used
   // for fast creation of scopes after scope barriers.
   if (!impl->blocks()->is_empty()) {
     Object** limit = &impl->blocks()->last()[kHandleBlockSize];
     if (current_.limit != limit) {
       current_.limit = limit;
+      ASSERT(limit - current_.next < kHandleBlockSize);
     }
   }
 
   // If we still haven't found a slot for the handle, we extend the
   // current handle scope by allocating a new handle block.
   if (result == current_.limit) {
     // If there's a spare block, use it for growing the current scope.
     result = impl->GetSpareOrNewBlock();
     // Add the extension to the global list of blocks, but count the
     // extension as part of the current scope.
     impl->blocks()->Add(result);
-    current_.extensions++;
     current_.limit = &result[kHandleBlockSize];
   }
 
   return result;
 }
 
 
 void HandleScope::DeleteExtensions() {
-  ASSERT(current_.extensions != 0);
-  HandleScopeImplementer::instance()->DeleteExtensions(current_.extensions);
+  HandleScopeImplementer::instance()->DeleteExtensions(current_.limit);
 }
 
 
 void HandleScope::ZapRange(Object** start, Object** end) {
-  if (start == NULL) return;
-  for (Object** p = start; p < end; p++) {
+  ASSERT(end - start <= kHandleBlockSize);
+  for (Object** p = start; p != end; p++) {
     *reinterpret_cast<Address*>(p) = v8::internal::kHandleZapValue;
   }
 }
 
 
-Address HandleScope::current_extensions_address() {
-  return reinterpret_cast<Address>(&current_.extensions);
+Address HandleScope::current_level_address() {
+  return reinterpret_cast<Address>(&current_.level);
 }
 
 
 Address HandleScope::current_next_address() {
   return reinterpret_cast<Address>(&current_.next);
 }
 
 
 Address HandleScope::current_limit_address() {
   return reinterpret_cast<Address>(&current_.limit);
@@ skipping 744 matching lines @@
 
 OptimizedObjectForAddingMultipleProperties::
 ~OptimizedObjectForAddingMultipleProperties() {
   // Reoptimize the object to allow fast property access.
   if (has_been_transformed_) {
     TransformToFastProperties(object_, unused_property_fields_);
   }
 }
 
 } }  // namespace v8::internal