Add a second kind of HandleScope that ties the lifetime of Handles created in its scope to the life…

src/handles.cc

 // 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 940 matching lines @@
   const int kRecursionBudget = 100;
   do {
     failure = false;
     len = Utf8LengthHelper(
         *str, 0, str->length(), false, kRecursionBudget, &failure, &dummy);
     if (failure) FlattenString(str);
   } while (failure);
   return len;
 }
 
+
+GatheringHandleScope::GatheringHandleScope(CompilationInfo* info)
+    : info_(info) {
+  Isolate* isolate = info->isolate();

[danno, 2012/06/24 11:07:03]

You should be able to put the code below in the ScopeHandleImplementation if you
here call:

impl->BeginDeferredHandleScope() 

here and remember the deferred handle scope. BTW, BeginDeferredHandleScope
should take a HandleScope as parameter rather than the explicit prev_limit_
parameter to encapsulate the implementation.

+  v8::ImplementationUtilities::HandleScopeData* current =
+      isolate->handle_scope_data();
+  prev_next_ = current->next;
+  prev_limit_ = current->limit;
+
+  HandleScopeImplementer* impl = isolate->handle_scope_implementer();
+  impl->begin_persistence();
+  Object** new_next = impl->GetSpareOrNewBlock();
+  Object** new_limit = &new_next[kHandleBlockSize];
+  impl->blocks()->Add(new_next);
+
+  current->next = new_next;
+  current->limit = new_limit;
+  current->level++;
+}
+
+
+GatheringHandleScope::~GatheringHandleScope() {
+  Isolate* isolate = info_->isolate();
+  HandleScopeImplementer* impl = isolate->handle_scope_implementer();
+  HandleScopeImplementer::PersistentExtensions* extensions =
+      impl->PersistExtensions(prev_limit_);

[danno, 2012/06/24 11:07:03]

All of the code below can be pushed to the impl if you call the DeferHandleScope
method here on the result of the BeginDeferredHandleScope method that you called
in the constructor.

+  info_->StorePersistentExtensions(extensions);
+
+  v8::ImplementationUtilities::HandleScopeData* current =
+      isolate->handle_scope_data();
+  current->next = prev_next_;
+  current->limit = prev_limit_;
+
+  impl->end_persistence();
+  current->level--;
+}
+
+
 } }  // namespace v8::internal