Tweak memory management in the serializer.

src/serialize.h

Index: src/serialize.h
diff --git a/src/serialize.h b/src/serialize.h
index 64164c803a931c61b4808b64a025ab2c4d4e6e55..02dd07e64eb2676e44007b9b7c5af01d3c3cada7 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -572,7 +572,7 @@ class Deserializer: public SerializerDeserializer {
   void FlushICacheForNewCodeObjects();
 
   // Pass a vector of externally-provided objects referenced by the snapshot.
-  // The ownership to its backing store is handed over as well.
+  // The ownership to its backing store is not handed over.
   void SetAttachedObjects(Vector<Handle<Object> > attached_objects) {
     attached_objects_ = attached_objects;
   }
@@ -703,6 +703,8 @@ class Serializer : public SerializerDeserializer {
     // External strings are serialized in a way to resemble sequential strings.
     void SerializeExternalString();
 
+    Address PrepareCode();
+
     Serializer* serializer_;
     HeapObject* object_;
     SnapshotByteSink* sink_;
@@ -750,6 +752,12 @@ class Serializer : public SerializerDeserializer {
   // of the serializer.  Initialize it on demand.
   void InitializeCodeAddressMap();
 
+  inline Address GetCodeBuffer(int size) {
+    if (size > code_buffer_.length()) code_buffer_.Dispose();
+    code_buffer_ = Vector<byte>::New(size);
+    return code_buffer_.start();
+  }
+
   inline uint32_t max_chunk_size(int space) const {
     DCHECK_LE(0, space);
     DCHECK_LT(space, kNumberOfSpaces);
@@ -784,6 +792,8 @@ class Serializer : public SerializerDeserializer {
   uint32_t large_objects_total_size_;
   uint32_t seen_large_objects_index_;
 
+  Vector<byte> code_buffer_;
+
   DISALLOW_COPY_AND_ASSIGN(Serializer);
 };