Request for comments on overall approach.

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
diff --git a/runtime/vm/raw_object.h b/runtime/vm/raw_object.h
index db7191d1b36e7c9c9bfde9c4fea7d296ae6bd181..d5a3129600bd7a747d98be74463cbca7445dc891 100644
--- a/runtime/vm/raw_object.h
+++ b/runtime/vm/raw_object.h
@@ -236,6 +236,10 @@ class RawObject {
     return (addr & kNewObjectAlignmentOffset) == kOldObjectAlignmentOffset;
   }
 
+  bool IsFree() const {
+    return FreeBit::decode(ptr()->tags_);
+  }
+
   // Support for GC marking bit.
   bool IsMarked() const {
     return MarkBit::decode(ptr()->tags_);
@@ -312,8 +316,15 @@ class RawObject {
   static bool IsBuiltinListClassIndex(intptr_t index);
   static bool IsByteArrayClassIndex(intptr_t index);
 
+  RawClass* GetClass() const {
+    return GetClass(ptr()->tags_);

[Ivan Posva, 2012/05/26 04:34:46]

If anything then all we should have here is GetClassId().

[Vyacheslav Egorov (Google), 2012/05/26 16:48:22]

Will do.

+  }
+
+  static RawClass* GetClass(uword tags);

[Ivan Posva, 2012/05/26 04:34:46]

Does not belong here. Please move to Object, or ClassTable.

[Vyacheslav Egorov (Google), 2012/05/26 16:48:22]

Will do.

+
+  class CreatedFromSnapshotTag : public BitField<bool, kFromSnapshotBit, 1> {};
+
  protected:
-  RawClass* class_;
   uword tags_;  // Various object tags (bits).
 
  private:
@@ -323,7 +334,6 @@ class RawObject {
 
   class CanonicalObjectTag : public BitField<bool, kCanonicalBit, 1> {};
 
-  class CreatedFromSnapshotTag : public BitField<bool, kFromSnapshotBit, 1> {};
 
   RawObject* ptr() const {
     ASSERT(IsHeapObject());
@@ -401,6 +411,7 @@ class RawClass : public RawObject {
   friend class RawInstructions;
   friend RawClass* AllocateFakeClass();
   friend class SnapshotReader;
+  friend class ClassTable;
 };