Age code to allow reclaiming old unexecuted functions

src/mark-compact.cc

Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index 412bc6b736fb9b6d58820476c0fdf881cca56074..f9ac577e83260b3b2d59a7563ca225ef0893ecd1 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -62,6 +62,7 @@ MarkCompactCollector::MarkCompactCollector() :  // NOLINT
       sweep_precisely_(false),
       reduce_memory_footprint_(false),
       abort_incremental_marking_(false),
+      marking_parity_(ODD_MARKING_PARITY),
       compacting_(false),
       was_marked_incrementally_(false),
       tracer_(NULL),
@@ -404,6 +405,13 @@ void MarkCompactCollector::CollectGarbage() {
 
   Finish();
 
+  if (marking_parity_ == EVEN_MARKING_PARITY) {
+    marking_parity_ = ODD_MARKING_PARITY;
+  } else {
+    ASSERT(marking_parity_ == ODD_MARKING_PARITY);
+    marking_parity_ = EVEN_MARKING_PARITY;
+  }
+
   tracer_ = NULL;
 }
 
@@ -2344,6 +2352,14 @@ class PointersUpdatingVisitor: public ObjectVisitor {
     }
   }
 
+  void VisitCodeAgeSequence(RelocInfo* rinfo) {
+    ASSERT(RelocInfo::IsCodeAgeSequence(rinfo->rmode()));
+    Object* stub = rinfo->code_age_stub();
+    ASSERT(stub != NULL);
+    VisitPointer(&stub);
+    rinfo->set_code_age_stub(Code::cast(stub));

[Michael Starzinger, 2012/11/02 15:29:34]

Can we use the "if (target != old_target)" pattern here as well? Thereby we
avoid flushing the instruction cache when the stub doesn't actually change.

[danno, 2012/11/09 13:05:30]

Done.

+  }
+
   void VisitDebugTarget(RelocInfo* rinfo) {
     ASSERT((RelocInfo::IsJSReturn(rinfo->rmode()) &&
             rinfo->IsPatchedReturnSequence()) ||