Age code to allow reclaiming old unexecuted functions

src/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 44 matching lines @@
 // -------------------------------------------------------------------------
 // MarkCompactCollector
 
 MarkCompactCollector::MarkCompactCollector() :  // NOLINT
 #ifdef DEBUG
       state_(IDLE),
 #endif
       sweep_precisely_(false),
       reduce_memory_footprint_(false),
       abort_incremental_marking_(false),
+      marking_parity_(ODD_MARKING_PARITY),
       compacting_(false),
       was_marked_incrementally_(false),
       tracer_(NULL),
       migration_slots_buffer_(NULL),
       heap_(NULL),
       code_flusher_(NULL),
       encountered_weak_maps_(NULL) { }
 
 
 #ifdef VERIFY_HEAP
@@ skipping 322 matching lines @@
   if (!FLAG_collect_maps) ReattachInitialMaps();
 
 #ifdef DEBUG
   if (FLAG_verify_native_context_separation) {
     VerifyNativeContextSeparation(heap_);
   }
 #endif
 
   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;
 }
 
 
 #ifdef VERIFY_HEAP
 void MarkCompactCollector::VerifyMarkbitsAreClean(PagedSpace* space) {
   PageIterator it(space);
 
   while (it.has_next()) {
     Page* p = it.next();
@@ skipping 1920 matching lines @@
   void VisitCodeTarget(RelocInfo* rinfo) {
     ASSERT(RelocInfo::IsCodeTarget(rinfo->rmode()));
     Object* target = Code::GetCodeFromTargetAddress(rinfo->target_address());
     Object* old_target = target;
     VisitPointer(&target);
     if (target != old_target) {
       rinfo->set_target_address(Code::cast(target)->instruction_start());
     }
   }
 
+  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()) ||
            (RelocInfo::IsDebugBreakSlot(rinfo->rmode()) &&
             rinfo->IsPatchedDebugBreakSlotSequence()));
     Object* target = Code::GetCodeFromTargetAddress(rinfo->call_address());
     VisitPointer(&target);
     rinfo->set_call_address(Code::cast(target)->instruction_start());
   }
 
@@ skipping 1416 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal