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

src/api.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 6359 matching lines @@
   memcpy(this, storage, sizeof(*this));
   *isolate_->handle_scope_data() = handle_scope_data_;
   return storage + ArchiveSpacePerThread();
 }
 
 
 void HandleScopeImplementer::IterateThis(ObjectVisitor* v) {
   // Iterate over all handles in the blocks except for the last.
   for (int i = blocks()->length() - 2; i >= 0; --i) {
     Object** block = blocks()->at(i);
-    v->VisitPointers(block, &block[kHandleBlockSize]);
+    if (block == last_non_persistent_block_) {
+      ASSERT(last_non_persistent_handle_ >= block &&
+             last_non_persistent_handle_ <
+             (&block[kHandleBlockSize]));
+      v->VisitPointers(block, last_non_persistent_handle_);
+    } else {
+      v->VisitPointers(block, &block[kHandleBlockSize]);
+    }
   }
 
   // Iterate over live handles in the last block (if any).
   if (!blocks()->is_empty()) {
     v->VisitPointers(blocks()->last(), handle_scope_data_.next);
+    ASSERT(!has_compilation_block_ ||

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

I can't find has_compilation_block_ anywhere else.

+           blocks()->last() != last_non_persistent_block_);
   }
 
   if (!saved_contexts_.is_empty()) {
     Object** start = reinterpret_cast<Object**>(&saved_contexts_.first());
     v->VisitPointers(start, start + saved_contexts_.length());
   }
+
+  for (PersistentExtensions* extension = persistent_extensions_head_; extension;
+       extension = extension->next) {
+    if (!extension->blocks.is_empty()) {
+      for (int i = 0; i < extension->blocks.length() - 1; i++) {
+        v->VisitPointers(extension->blocks[i],
+                         &(extension->blocks[i][kHandleBlockSize]));
+      }
+    }
+    ASSERT(extension->last_block_end <
+           &extension->blocks.last()[kHandleBlockSize]);
+    ASSERT(extension->last_block_end >= extension->blocks.last());
+    v->VisitPointers(extension->blocks.last(), extension->last_block_end);
+  }
 }
 
 
 void HandleScopeImplementer::Iterate(ObjectVisitor* v) {
   v8::ImplementationUtilities::HandleScopeData* current =
       isolate_->handle_scope_data();
   handle_scope_data_ = *current;
   IterateThis(v);
 }
 
 
 char* HandleScopeImplementer::Iterate(ObjectVisitor* v, char* storage) {
   HandleScopeImplementer* scope_implementer =
       reinterpret_cast<HandleScopeImplementer*>(storage);
   scope_implementer->IterateThis(v);
   return storage + ArchiveSpacePerThread();
 }
 
+
+HandleScopeImplementer::PersistentExtensions*
+HandleScopeImplementer::PersistExtensions(Object** prev_limit) {
+  PersistentExtensions* extension = new PersistentExtensions;
+  while (!blocks_.is_empty()) {
+    internal::Object** block_start = blocks_.last();
+    internal::Object** block_limit = block_start + kHandleBlockSize;
+
+    // We should not need to check for NoHandleAllocation here.
+    // Assert this.
+    ASSERT(prev_limit == block_limit ||
+           !(block_start <= prev_limit && prev_limit <= block_limit));
+    if (prev_limit == block_limit) break;
+    extension->blocks.Add(blocks_.last());
+    blocks_.RemoveLast();
+  }
+
+  ASSERT(!blocks_.is_empty() && prev_limit != NULL);
+
+  extension->next = persistent_extensions_head_;
+  extension->previous = NULL;
+  extension->last_block_end = isolate_->handle_scope_data()->next;
+  persistent_extensions_head_ = extension;
+  return extension;
+}
+
+
+void HandleScopeImplementer::ReleaseExtensions(
+    PersistentExtensions* extension) {
+  if (persistent_extensions_head_ == extension) {
+    persistent_extensions_head_ = extension->next;
+  }
+  if (extension->next != NULL) {
+    extension->next->previous = extension->previous;
+  }
+  if (extension->previous != NULL) {
+    extension->previous->next = extension->next;
+  }
+
+  for (int i = 0; i < extension->blocks.length(); i++) {
+#ifdef DEBUG
+    HandleScope::ZapRange(extension->blocks[i],
+                          &extension->blocks[i][kHandleBlockSize]);
+#endif
+    if (spare_ != NULL) DeleteArray(spare_);
+    spare_ = extension->blocks[i];
+  }
+  delete extension;
+}
+
 } }  // namespace v8::internal