src/incremental-marking-inl.h

// Copyright 2012 the V8 project authors. All rights reserved.
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#ifndef V8_INCREMENTAL_MARKING_INL_H_
#define V8_INCREMENTAL_MARKING_INL_H_

#include "incremental-marking.h"

namespace v8 {
namespace internal {


bool IncrementalMarking::BaseRecordWrite(HeapObject* obj,
                                         Object** slot,
                                         Object* value) {
  MarkBit value_bit = Marking::MarkBitFrom(HeapObject::cast(value));
  if (Marking::IsWhite(value_bit)) {
    MarkBit obj_bit = Marking::MarkBitFrom(obj);
    if (Marking::IsBlack(obj_bit)) {
      BlackToGreyAndUnshift(obj, obj_bit);
      RestartIfNotMarking();
    }

    // Object is either grey or white.  It will be scanned if survives.
    return false;
  }
  return true;
}


void IncrementalMarking::RecordWrite(HeapObject* obj,
                                     Object** slot,
                                     Object* value) {
  if (IsMarking() && value->NonFailureIsHeapObject()) {
    RecordWriteSlow(obj, slot, value);
  }
}


void IncrementalMarking::RecordWriteOfCodeEntry(JSFunction* host,
                                                Object** slot,
                                                Code* value) {
  if (IsMarking()) RecordWriteOfCodeEntrySlow(host, slot, value);
}


void IncrementalMarking::RecordWriteIntoCode(HeapObject* obj,
                                             RelocInfo* rinfo,
                                             Object* value) {
  if (IsMarking() && value->NonFailureIsHeapObject()) {
    RecordWriteIntoCodeSlow(obj, rinfo, value);
  }
}


void IncrementalMarking::RecordWrites(HeapObject* obj) {
  if (IsMarking()) {
    MarkBit obj_bit = Marking::MarkBitFrom(obj);
    if (Marking::IsBlack(obj_bit)) {
      BlackToGreyAndUnshift(obj, obj_bit);
      RestartIfNotMarking();
    }
  }
}


void IncrementalMarking::BlackToGreyAndUnshift(HeapObject* obj,
                                               MarkBit mark_bit) {
  ASSERT(Marking::MarkBitFrom(obj) == mark_bit);
  ASSERT(obj->Size() >= 2*kPointerSize);
  ASSERT(IsMarking());
  Marking::BlackToGrey(mark_bit);
  int obj_size = obj->Size();
  MemoryChunk::IncrementLiveBytesFromGC(obj->address(), -obj_size);
  bytes_scanned_ -= obj_size;
  int64_t old_bytes_rescanned = bytes_rescanned_;
  bytes_rescanned_ = old_bytes_rescanned + obj_size;
  if ((bytes_rescanned_ >> 20) != (old_bytes_rescanned >> 20)) {
    if (bytes_rescanned_ > 2 * heap_->PromotedSpaceSizeOfObjects()) {
      // If we have queued twice the heap size for rescanning then we are
      // going around in circles, scanning the same objects again and again
      // as the program mutates the heap faster than we can incrementally
      // trace it.  In this case we switch to non-incremental marking in
      // order to finish off this marking phase.
      if (FLAG_trace_gc) {
        PrintPID("Hurrying incremental marking because of lack of progress\n");
      }
      allocation_marking_factor_ = kMaxAllocationMarkingFactor;
    }
  }

  marking_deque_.UnshiftGrey(obj);
}


void IncrementalMarking::WhiteToGreyAndPush(HeapObject* obj, MarkBit mark_bit) {
  Marking::WhiteToGrey(mark_bit);
  marking_deque_.PushGrey(obj);
}


bool IncrementalMarking::MarkObjectAndPush(HeapObject* obj) {
  MarkBit mark_bit = Marking::MarkBitFrom(obj);
  if (!mark_bit.Get()) {
    WhiteToGreyAndPush(obj, mark_bit);
    return true;
  }
  return false;
}


bool IncrementalMarking::MarkObjectWithoutPush(HeapObject* obj) {
  MarkBit mark_bit = Marking::MarkBitFrom(obj);
  if (!mark_bit.Get()) {
    mark_bit.Set();
    MemoryChunk::IncrementLiveBytesFromGC(obj->address(), obj->Size());
    return true;
  }
  return false;
}


} }  // namespace v8::internal

#endif  // V8_INCREMENTAL_MARKING_INL_H_