Reviewers: Vyacheslav Egorov,
Description:
Simplify the write barrier.
Please review this at http://codereview.chromium.org/8537014/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/incremental-marking.cc
M src/mark-compact-inl.h
M src/mark-compact.cc
M src/spaces.h
Index: src/incremental-marking.cc
===================================================================
--- src/incremental-marking.cc (revision 9979)
+++ src/incremental-marking.cc (working copy)
@@ -223,12 +223,7 @@
INLINE(void MarkObject(Object* obj)) {
HeapObject* heap_object = HeapObject::cast(obj);
MarkBit mark_bit = Marking::MarkBitFrom(heap_object);
- if (mark_bit.data_only()) {
- if (incremental_marking_->MarkBlackOrKeepGrey(mark_bit)) {
- MemoryChunk::IncrementLiveBytes(heap_object->address(),
- heap_object->Size());
- }
- } else if (Marking::IsWhite(mark_bit)) {
+ if (Marking::IsWhite(mark_bit)) {
incremental_marking_->WhiteToGreyAndPush(heap_object, mark_bit);
}
}
@@ -261,15 +256,8 @@
HeapObject* heap_object = HeapObject::cast(obj);
MarkBit mark_bit = Marking::MarkBitFrom(heap_object);
- if (mark_bit.data_only()) {
- if (incremental_marking_->MarkBlackOrKeepGrey(mark_bit)) {
- MemoryChunk::IncrementLiveBytes(heap_object->address(),
- heap_object->Size());
- }
- } else {
- if (Marking::IsWhite(mark_bit)) {
- incremental_marking_->WhiteToGreyAndPush(heap_object, mark_bit);
- }
+ if (Marking::IsWhite(mark_bit)) {
+ incremental_marking_->WhiteToGreyAndPush(heap_object, mark_bit);
}
}
Index: src/mark-compact-inl.h
===================================================================
--- src/mark-compact-inl.h (revision 9979)
+++ src/mark-compact-inl.h (working copy)
@@ -39,8 +39,7 @@
MarkBit Marking::MarkBitFrom(Address addr) {
MemoryChunk* p = MemoryChunk::FromAddress(addr);
- return p->markbits()->MarkBitFromIndex(p->AddressToMarkbitIndex(addr),
- p->ContainsOnlyData());
+ return p->markbits()->MarkBitFromIndex(p->AddressToMarkbitIndex(addr));
}
Index: src/mark-compact.cc
===================================================================
--- src/mark-compact.cc (revision 9979)
+++ src/mark-compact.cc (working copy)
@@ -1742,7 +1742,7 @@
int trailing_zeros =
CompilerIntrinsics::CountTrailingZeros(grey_objects);
grey_objects >>= trailing_zeros;
offset += trailing_zeros;
- MarkBit markbit(&cells[cell_index], 1 << offset, false);
+ MarkBit markbit(&cells[cell_index], 1 << offset);
ASSERT(Marking::IsGrey(markbit));
Marking::GreyToBlack(markbit);
Address addr = cell_base + offset * kPointerSize;
Index: src/spaces.h
===================================================================
--- src/spaces.h (revision 9979)
+++ src/spaces.h (working copy)
@@ -124,8 +124,8 @@
public:
typedef uint32_t CellType;
- inline MarkBit(CellType* cell, CellType mask, bool data_only)
- : cell_(cell), mask_(mask), data_only_(data_only) { }
+ inline MarkBit(CellType* cell, CellType mask)
+ : cell_(cell), mask_(mask) { }
inline CellType* cell() { return cell_; }
inline CellType mask() { return mask_; }
@@ -140,25 +140,18 @@
inline bool Get() { return (*cell_ & mask_) != 0; }
inline void Clear() { *cell_ &= ~mask_; }
- inline bool data_only() { return data_only_; }
-
inline MarkBit Next() {
CellType new_mask = mask_ << 1;
if (new_mask == 0) {
- return MarkBit(cell_ + 1, 1, data_only_);
+ return MarkBit(cell_ + 1, 1);
} else {
- return MarkBit(cell_, new_mask, data_only_);
+ return MarkBit(cell_, new_mask);
}
}
private:
CellType* cell_;
CellType mask_;
- // This boolean indicates that the object is in a data-only space with no
- // pointers. This enables some optimizations when marking.
- // It is expected that this field is inlined and turned into control flow
- // at the place where the MarkBit object is created.
- bool data_only_;
};
@@ -214,10 +207,10 @@
return reinterpret_cast<Bitmap*>(addr);
}
- inline MarkBit MarkBitFromIndex(uint32_t index, bool data_only = false) {
+ inline MarkBit MarkBitFromIndex(uint32_t index) {
MarkBit::CellType mask = 1 << (index & kBitIndexMask);
MarkBit::CellType* cell = this->cells() + (index >> kBitsPerCellLog2);
- return MarkBit(cell, mask, data_only);
+ return MarkBit(cell, mask);
}
static inline void Clear(MemoryChunk* chunk);
--
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