Use external byte arrays for token stream, this moves the token stream out of the isolate heap. For…

vm/snapshot.h

 // Copyright (c) 2012, 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_SNAPSHOT_H_
 #define VM_SNAPSHOT_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/bitfield.h"
 #include "vm/datastream.h"
 #include "vm/globals.h"
 #include "vm/growable_array.h"
 #include "vm/isolate.h"
 #include "vm/visitor.h"
 
 namespace dart {
 
 // Forward declarations.
 class AbstractType;
 class AbstractTypeArguments;
 class Array;
 class Class;
 class ClassTable;
+class ExternalUint8Array;
 class GrowableObjectArray;
 class Heap;
 class Library;
 class Object;
 class ObjectStore;
 class RawAbstractTypeArguments;
 class RawApiError;
 class RawArray;
 class RawBigint;
 class RawClass;
@@ skipping 14 matching lines @@
 class RawPatchClass;
 class RawScript;
 class RawSmi;
 class RawTokenStream;
 class RawType;
 class RawTypeParameter;
 class RawTypeArguments;
 class RawTwoByteString;
 class RawUnresolvedClass;
 class String;
+class TokenStream;
 
 // Serialized object header encoding is as follows:
 // - Smi: the Smi value is written as is (last bit is not tagged).
 // - VM object (from VM isolate): (object id in vm isolate | 0x3)
 //   This valus is serialized as a negative number.
 //   (note VM objects are never serialized they are expected to be found
 //    using ths unique ID assigned to them).
 // - Reference to object that has already been written: (object id | 0x3)
 //   This valus is serialized as a positive number.
 // - Object that is seen for the first time (inlined in the stream):
@@ skipping 93 matching lines @@
   intptr_t ReadIntptrValue() {
     int64_t value = Read<int64_t>();
     ASSERT((value <= kIntptrMax) && (value >= kIntptrMin));
     return value;
   }
 
   void ReadBytes(uint8_t* addr, intptr_t len) {
     stream_.ReadBytes(addr, len);
   }
 
+  const uint8_t* CurrentBufferAddress() const {
+    return stream_.AddressOfCurrentPosition();
+  }
+
+  void Advance(intptr_t value) {
+    stream_.Advance(value);
+  }
+
   RawSmi* ReadAsSmi();
   intptr_t ReadSmiValue();
 
   // Negative header value indicates VM isolate object id.
   bool IsVMIsolateObject(intptr_t header_value) { return (header_value < 0); }
   intptr_t GetVMIsolateObjectId(intptr_t header_val) {
     ASSERT(IsVMIsolateObject(header_val));
     intptr_t value = -header_val;  // Header is negative for VM isolate objects.
     ASSERT(SerializedHeaderTag::decode(value) == kObjectId);
     return SerializedHeaderData::decode(value);
@@ skipping 15 matching lines @@
 
   Isolate* isolate() const { return isolate_; }
   Heap* heap() const { return isolate_->heap(); }
   ObjectStore* object_store() const { return isolate_->object_store(); }
   ClassTable* class_table() const { return isolate_->class_table(); }
   Object* ObjectHandle() { return &obj_; }
   String* StringHandle() { return &str_; }
   AbstractType* TypeHandle() { return &type_; }
   AbstractTypeArguments* TypeArgumentsHandle() { return &type_arguments_; }
   Array* TokensHandle() { return &tokens_; }
+  TokenStream* StreamHandle() { return &stream_; }
+  ExternalUint8Array* DataHandle() { return &data_; }
 
   // Reads an object.
   RawObject* ReadObject();
 
   // Add object to backward references.
   void AddBackRef(intptr_t id, Object* obj, DeserializeState state);
 
   // Get an object from the backward references list.
   Object* GetBackRef(intptr_t id);
 
@@ skipping 70 matching lines @@
 
   Snapshot::Kind kind_;  // Indicates type of snapshot(full, script, message).
   Isolate* isolate_;  // Current isolate.
   Class& cls_;  // Temporary Class handle.
   Object& obj_;  // Temporary Object handle.
   String& str_;  // Temporary String handle.
   Library& library_;  // Temporary library handle.
   AbstractType& type_;  // Temporary type handle.
   AbstractTypeArguments& type_arguments_;  // Temporary type argument handle.
   Array& tokens_;  // Temporary tokens handle.
+  TokenStream& stream_;  // Temporary token stream handle.
+  ExternalUint8Array& data_;  // Temporary stream data handle.
   GrowableArray<BackRefNode*> backward_references_;
 
   friend class ApiError;
   friend class Array;
   friend class Class;
   friend class Context;
   friend class ContextScope;
   friend class Field;
   friend class Function;
   friend class GrowableObjectArray;
@@ skipping 238 matching lines @@
  private:
   SnapshotWriter* writer_;
   bool as_references_;
 
   DISALLOW_COPY_AND_ASSIGN(SnapshotWriterVisitor);
 };
 
 }  // namespace dart
 
 #endif  // VM_SNAPSHOT_H_