Refactor how embedded pointers are visited.

src/mark-compact.h

Index: src/mark-compact.h
diff --git a/src/mark-compact.h b/src/mark-compact.h
index 86850369a906029c2075c000df787009f72013ae..e93170d98178f611bd05a1b27aafcbe583d39e89 100644
--- a/src/mark-compact.h
+++ b/src/mark-compact.h
@@ -320,6 +320,7 @@ class SlotsBuffer {
     CODE_ENTRY_SLOT,
     DEBUG_TARGET_SLOT,
     JS_RETURN_SLOT,
+    EMBEDDED_OBJECT_SLOT,

[Vyacheslav Egorov (Chromium), 2011/10/12 14:21:53]

micro opt idea: consider placing it first (or in the middle) depending on the
way switch over slot types is compiled in visit function (rationale: there are
currently much more EMBEDDED_OBJECT_SLOTs than anything else)

[Michael Starzinger, 2011/10/12 15:38:36]

Done. On both ia32 and x64 it is compiled as a lookup table. But I placed it
first to indicate (syntactically) that it is the most frequent type.

     NUMBER_OF_SLOT_TYPES
   };
 
@@ -540,6 +541,7 @@ class MarkCompactCollector {
 
   void RecordRelocSlot(RelocInfo* rinfo, Code* target);
   void RecordCodeEntrySlot(Address slot, Code* target);
+  void RecordEmbeddedSlot(RelocInfo* rinfo, Object* target);
 
   INLINE(void RecordSlot(Object** anchor_slot, Object** slot, Object* object));