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Unified Diff: src/heap.cc

Issue 2274001: Revert r4715. (Closed) Base URL: http://v8.googlecode.com/svn/branches/bleeding_edge/
Patch Set: Created 10 years, 7 months ago
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Index: src/heap.cc
===================================================================
--- src/heap.cc (revision 4722)
+++ src/heap.cc (working copy)
@@ -326,6 +326,13 @@
}
if (FLAG_gc_verbose) Print();
+
+ if (FLAG_print_rset) {
+ // Not all spaces have remembered set bits that we care about.
+ old_pointer_space_->PrintRSet();
+ map_space_->PrintRSet();
+ lo_space_->PrintRSet();
+ }
#endif
#if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
@@ -512,8 +519,9 @@
Heap::CollectGarbage(cell_space_size, CELL_SPACE);
gc_performed = true;
}
- // We add a slack-factor of 2 in order to have space for a series of
- // large-object allocations that are only just larger than the page size.
+ // We add a slack-factor of 2 in order to have space for the remembered
+ // set and a series of large-object allocations that are only just larger
+ // than the page size.
large_object_size *= 2;
// The ReserveSpace method on the large object space checks how much
// we can expand the old generation. This includes expansion caused by
@@ -564,25 +572,6 @@
}
-#ifdef DEBUG
-
-enum PageWatermarkValidity {
- ALL_VALID,
- ALL_INVALID
-};
-
-static void VerifyPageWatermarkValidity(PagedSpace* space,
- PageWatermarkValidity validity) {
- PageIterator it(space, PageIterator::PAGES_IN_USE);
- bool expected_value = (validity == ALL_VALID);
- while (it.has_next()) {
- Page* page = it.next();
- ASSERT(page->IsWatermarkValid() == expected_value);
- }
-}
-#endif
-
-
void Heap::PerformGarbageCollection(AllocationSpace space,
GarbageCollector collector,
GCTracer* tracer) {
@@ -827,20 +816,6 @@
gc_state_ = SCAVENGE;
- Page::FlipMeaningOfInvalidatedWatermarkFlag();
-#ifdef DEBUG
- VerifyPageWatermarkValidity(old_pointer_space_, ALL_VALID);
- VerifyPageWatermarkValidity(map_space_, ALL_VALID);
-#endif
-
- // We do not update an allocation watermark of the top page during linear
- // allocation to avoid overhead. So to maintain the watermark invariant
- // we have to manually cache the watermark and mark the top page as having an
- // invalid watermark. This guarantees that dirty regions iteration will use a
- // correct watermark even if a linear allocation happens.
- old_pointer_space_->FlushTopPageWatermark();
- map_space_->FlushTopPageWatermark();
-
// Implements Cheney's copying algorithm
LOG(ResourceEvent("scavenge", "begin"));
@@ -883,18 +858,10 @@
// Copy objects reachable from the old generation. By definition,
// there are no intergenerational pointers in code or data spaces.
- IterateDirtyRegions(old_pointer_space_,
- &IteratePointersInDirtyRegion,
- &ScavengePointer,
- WATERMARK_CAN_BE_INVALID);
+ IterateRSet(old_pointer_space_, &ScavengePointer);
+ IterateRSet(map_space_, &ScavengePointer);
+ lo_space_->IterateRSet(&ScavengePointer);
- IterateDirtyRegions(map_space_,
- &IteratePointersInDirtyMapsRegion,
- &ScavengePointer,
- WATERMARK_CAN_BE_INVALID);
-
- lo_space_->IterateDirtyRegions(&ScavengePointer);
-
// Copy objects reachable from cells by scavenging cell values directly.
HeapObjectIterator cell_iterator(cell_space_);
for (HeapObject* cell = cell_iterator.next();
@@ -996,8 +963,9 @@
// Copy the from-space object to its new location (given by the
// forwarding address) and fix its map.
HeapObject* target = source->map_word().ToForwardingAddress();
- int size = source->SizeFromMap(map);
- CopyBlock(target->address(), source->address(), size);
+ CopyBlock(reinterpret_cast<Object**>(target->address()),
+ reinterpret_cast<Object**>(source->address()),
+ source->SizeFromMap(map));
target->set_map(map);
#if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
@@ -1005,10 +973,8 @@
RecordCopiedObject(target);
#endif
// Visit the newly copied object for pointers to new space.
- ASSERT(!target->IsMap());
- IterateAndMarkPointersToNewSpace(target->address(),
- target->address() + size,
- &ScavengePointer);
+ target->Iterate(scavenge_visitor);
+ UpdateRSet(target);
}
// Take another spin if there are now unswept objects in new space
@@ -1019,6 +985,117 @@
}
+void Heap::ClearRSetRange(Address start, int size_in_bytes) {
+ uint32_t start_bit;
+ Address start_word_address =
+ Page::ComputeRSetBitPosition(start, 0, &start_bit);
+ uint32_t end_bit;
+ Address end_word_address =
+ Page::ComputeRSetBitPosition(start + size_in_bytes - kIntSize,
+ 0,
+ &end_bit);
+
+ // We want to clear the bits in the starting word starting with the
+ // first bit, and in the ending word up to and including the last
+ // bit. Build a pair of bitmasks to do that.
+ uint32_t start_bitmask = start_bit - 1;
+ uint32_t end_bitmask = ~((end_bit << 1) - 1);
+
+ // If the start address and end address are the same, we mask that
+ // word once, otherwise mask the starting and ending word
+ // separately and all the ones in between.
+ if (start_word_address == end_word_address) {
+ Memory::uint32_at(start_word_address) &= (start_bitmask | end_bitmask);
+ } else {
+ Memory::uint32_at(start_word_address) &= start_bitmask;
+ Memory::uint32_at(end_word_address) &= end_bitmask;
+ start_word_address += kIntSize;
+ memset(start_word_address, 0, end_word_address - start_word_address);
+ }
+}
+
+
+class UpdateRSetVisitor: public ObjectVisitor {
+ public:
+
+ void VisitPointer(Object** p) {
+ UpdateRSet(p);
+ }
+
+ void VisitPointers(Object** start, Object** end) {
+ // Update a store into slots [start, end), used (a) to update remembered
+ // set when promoting a young object to old space or (b) to rebuild
+ // remembered sets after a mark-compact collection.
+ for (Object** p = start; p < end; p++) UpdateRSet(p);
+ }
+ private:
+
+ void UpdateRSet(Object** p) {
+ // The remembered set should not be set. It should be clear for objects
+ // newly copied to old space, and it is cleared before rebuilding in the
+ // mark-compact collector.
+ ASSERT(!Page::IsRSetSet(reinterpret_cast<Address>(p), 0));
+ if (Heap::InNewSpace(*p)) {
+ Page::SetRSet(reinterpret_cast<Address>(p), 0);
+ }
+ }
+};
+
+
+int Heap::UpdateRSet(HeapObject* obj) {
+ ASSERT(!InNewSpace(obj));
+ // Special handling of fixed arrays to iterate the body based on the start
+ // address and offset. Just iterating the pointers as in UpdateRSetVisitor
+ // will not work because Page::SetRSet needs to have the start of the
+ // object for large object pages.
+ if (obj->IsFixedArray()) {
+ FixedArray* array = FixedArray::cast(obj);
+ int length = array->length();
+ for (int i = 0; i < length; i++) {
+ int offset = FixedArray::kHeaderSize + i * kPointerSize;
+ ASSERT(!Page::IsRSetSet(obj->address(), offset));
+ if (Heap::InNewSpace(array->get(i))) {
+ Page::SetRSet(obj->address(), offset);
+ }
+ }
+ } else if (!obj->IsCode()) {
+ // Skip code object, we know it does not contain inter-generational
+ // pointers.
+ UpdateRSetVisitor v;
+ obj->Iterate(&v);
+ }
+ return obj->Size();
+}
+
+
+void Heap::RebuildRSets() {
+ // By definition, we do not care about remembered set bits in code,
+ // data, or cell spaces.
+ map_space_->ClearRSet();
+ RebuildRSets(map_space_);
+
+ old_pointer_space_->ClearRSet();
+ RebuildRSets(old_pointer_space_);
+
+ Heap::lo_space_->ClearRSet();
+ RebuildRSets(lo_space_);
+}
+
+
+void Heap::RebuildRSets(PagedSpace* space) {
+ HeapObjectIterator it(space);
+ for (HeapObject* obj = it.next(); obj != NULL; obj = it.next())
+ Heap::UpdateRSet(obj);
+}
+
+
+void Heap::RebuildRSets(LargeObjectSpace* space) {
+ LargeObjectIterator it(space);
+ for (HeapObject* obj = it.next(); obj != NULL; obj = it.next())
+ Heap::UpdateRSet(obj);
+}
+
+
#if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
void Heap::RecordCopiedObject(HeapObject* obj) {
bool should_record = false;
@@ -1044,7 +1121,9 @@
HeapObject* target,
int size) {
// Copy the content of source to target.
- CopyBlock(target->address(), source->address(), size);
+ CopyBlock(reinterpret_cast<Object**>(target->address()),
+ reinterpret_cast<Object**>(source->address()),
+ size);
// Set the forwarding address.
source->set_map_word(MapWord::FromForwardingAddress(target));
@@ -1099,30 +1178,21 @@
if (object_size > MaxObjectSizeInPagedSpace()) {
result = lo_space_->AllocateRawFixedArray(object_size);
if (!result->IsFailure()) {
+ // Save the from-space object pointer and its map pointer at the
+ // top of the to space to be swept and copied later. Write the
+ // forwarding address over the map word of the from-space
+ // object.
HeapObject* target = HeapObject::cast(result);
+ promotion_queue.insert(object, first_word.ToMap());
+ object->set_map_word(MapWord::FromForwardingAddress(target));
- if (object->IsFixedArray()) {
- // Save the from-space object pointer and its map pointer at the
- // top of the to space to be swept and copied later. Write the
- // forwarding address over the map word of the from-space
- // object.
- promotion_queue.insert(object, first_word.ToMap());
- object->set_map_word(MapWord::FromForwardingAddress(target));
+ // Give the space allocated for the result a proper map by
+ // treating it as a free list node (not linked into the free
+ // list).
+ FreeListNode* node = FreeListNode::FromAddress(target->address());
+ node->set_size(object_size);
- // Give the space allocated for the result a proper map by
- // treating it as a free list node (not linked into the free
- // list).
- FreeListNode* node = FreeListNode::FromAddress(target->address());
- node->set_size(object_size);
-
- *p = target;
- } else {
- // In large object space only fixed arrays might possibly contain
- // intergenerational references.
- // All other objects can be copied immediately and not revisited.
- *p = MigrateObject(object, target, object_size);
- }
-
+ *p = target;
tracer()->increment_promoted_objects_size(object_size);
return;
}
@@ -1612,7 +1682,7 @@
// loop above because it needs to be allocated manually with the special
// hash code in place. The hash code for the hidden_symbol is zero to ensure
// that it will always be at the first entry in property descriptors.
- obj = AllocateSymbol(CStrVector(""), 0, String::kZeroHash);
+ obj = AllocateSymbol(CStrVector(""), 0, String::kHashComputedMask);
if (obj->IsFailure()) return false;
hidden_symbol_ = String::cast(obj);
@@ -1848,9 +1918,6 @@
share->set_compiler_hints(0);
share->set_this_property_assignments_count(0);
share->set_this_property_assignments(undefined_value());
- share->set_num_literals(0);
- share->set_end_position(0);
- share->set_function_token_position(0);
return result;
}
@@ -2112,8 +2179,8 @@
: lo_space_->AllocateRaw(size);
if (result->IsFailure()) return result;
- reinterpret_cast<ByteArray*>(result)->set_map(byte_array_map());
- reinterpret_cast<ByteArray*>(result)->set_length(length);
+ reinterpret_cast<Array*>(result)->set_map(byte_array_map());
+ reinterpret_cast<Array*>(result)->set_length(length);
return result;
}
@@ -2128,8 +2195,8 @@
Object* result = AllocateRaw(size, space, OLD_DATA_SPACE);
if (result->IsFailure()) return result;
- reinterpret_cast<ByteArray*>(result)->set_map(byte_array_map());
- reinterpret_cast<ByteArray*>(result)->set_length(length);
+ reinterpret_cast<Array*>(result)->set_map(byte_array_map());
+ reinterpret_cast<Array*>(result)->set_length(length);
return result;
}
@@ -2245,7 +2312,9 @@
// Copy code object.
Address old_addr = code->address();
Address new_addr = reinterpret_cast<HeapObject*>(result)->address();
- CopyBlock(new_addr, old_addr, obj_size);
+ CopyBlock(reinterpret_cast<Object**>(new_addr),
+ reinterpret_cast<Object**>(old_addr),
+ obj_size);
// Relocate the copy.
Code* new_code = Code::cast(result);
ASSERT(!CodeRange::exists() || CodeRange::contains(code->address()));
@@ -2391,8 +2460,8 @@
// Copy the content. The arguments boilerplate doesn't have any
// fields that point to new space so it's safe to skip the write
// barrier here.
- CopyBlock(HeapObject::cast(result)->address(),
- boilerplate->address(),
+ CopyBlock(reinterpret_cast<Object**>(HeapObject::cast(result)->address()),
+ reinterpret_cast<Object**>(boilerplate->address()),
kArgumentsObjectSize);
// Set the two properties.
@@ -2614,8 +2683,8 @@
clone = AllocateRaw(object_size, NEW_SPACE, OLD_POINTER_SPACE);
if (clone->IsFailure()) return clone;
Address clone_address = HeapObject::cast(clone)->address();
- CopyBlock(clone_address,
- source->address(),
+ CopyBlock(reinterpret_cast<Object**>(clone_address),
+ reinterpret_cast<Object**>(source->address()),
object_size);
// Update write barrier for all fields that lie beyond the header.
RecordWrites(clone_address,
@@ -2627,8 +2696,8 @@
ASSERT(Heap::InNewSpace(clone));
// Since we know the clone is allocated in new space, we can copy
// the contents without worrying about updating the write barrier.
- CopyBlock(HeapObject::cast(clone)->address(),
- source->address(),
+ CopyBlock(reinterpret_cast<Object**>(HeapObject::cast(clone)->address()),
+ reinterpret_cast<Object**>(source->address()),
object_size);
}
@@ -2899,8 +2968,8 @@
Object* result = AllocateRaw(size, OLD_DATA_SPACE, OLD_DATA_SPACE);
if (result->IsFailure()) return result;
// Initialize the object.
- reinterpret_cast<FixedArray*>(result)->set_map(fixed_array_map());
- reinterpret_cast<FixedArray*>(result)->set_length(0);
+ reinterpret_cast<Array*>(result)->set_map(fixed_array_map());
+ reinterpret_cast<Array*>(result)->set_length(0);
return result;
}
@@ -2925,7 +2994,9 @@
if (obj->IsFailure()) return obj;
if (Heap::InNewSpace(obj)) {
HeapObject* dst = HeapObject::cast(obj);
- CopyBlock(dst->address(), src->address(), FixedArray::SizeFor(len));
+ CopyBlock(reinterpret_cast<Object**>(dst->address()),
+ reinterpret_cast<Object**>(src->address()),
+ FixedArray::SizeFor(len));
return obj;
}
HeapObject::cast(obj)->set_map(src->map());
@@ -2946,8 +3017,8 @@
Object* result = AllocateRawFixedArray(length);
if (!result->IsFailure()) {
// Initialize header.
- FixedArray* array = reinterpret_cast<FixedArray*>(result);
- array->set_map(fixed_array_map());
+ reinterpret_cast<Array*>(result)->set_map(fixed_array_map());
+ FixedArray* array = FixedArray::cast(result);
array->set_length(length);
// Initialize body.
ASSERT(!Heap::InNewSpace(undefined_value()));
@@ -2974,10 +3045,27 @@
space = LO_SPACE;
}
- AllocationSpace retry_space =
- (size <= MaxObjectSizeInPagedSpace()) ? OLD_POINTER_SPACE : LO_SPACE;
-
- return AllocateRaw(size, space, retry_space);
+ // Specialize allocation for the space.
+ Object* result = Failure::OutOfMemoryException();
+ if (space == NEW_SPACE) {
+ // We cannot use Heap::AllocateRaw() because it will not properly
+ // allocate extra remembered set bits if always_allocate() is true and
+ // new space allocation fails.
+ result = new_space_.AllocateRaw(size);
+ if (result->IsFailure() && always_allocate()) {
+ if (size <= MaxObjectSizeInPagedSpace()) {
+ result = old_pointer_space_->AllocateRaw(size);
+ } else {
+ result = lo_space_->AllocateRawFixedArray(size);
+ }
+ }
+ } else if (space == OLD_POINTER_SPACE) {
+ result = old_pointer_space_->AllocateRaw(size);
+ } else {
+ ASSERT(space == LO_SPACE);
+ result = lo_space_->AllocateRawFixedArray(size);
+ }
+ return result;
}
@@ -3025,7 +3113,7 @@
Object* Heap::AllocateHashTable(int length, PretenureFlag pretenure) {
Object* result = Heap::AllocateFixedArray(length, pretenure);
if (result->IsFailure()) return result;
- reinterpret_cast<HeapObject*>(result)->set_map(hash_table_map());
+ reinterpret_cast<Array*>(result)->set_map(hash_table_map());
ASSERT(result->IsHashTable());
return result;
}
@@ -3277,49 +3365,6 @@
#ifdef DEBUG
-static void DummyScavengePointer(HeapObject** p) {
-}
-
-
-static void VerifyPointersUnderWatermark(
- PagedSpace* space,
- DirtyRegionCallback visit_dirty_region) {
- PageIterator it(space, PageIterator::PAGES_IN_USE);
-
- while (it.has_next()) {
- Page* page = it.next();
- Address start = page->ObjectAreaStart();
- Address end = page->AllocationWatermark();
-
- Heap::IterateDirtyRegions(Page::kAllRegionsDirtyMarks,
- start,
- end,
- visit_dirty_region,
- &DummyScavengePointer);
- }
-}
-
-
-static void VerifyPointersUnderWatermark(LargeObjectSpace* space) {
- LargeObjectIterator it(space);
- for (HeapObject* object = it.next(); object != NULL; object = it.next()) {
- if (object->IsFixedArray()) {
- Address slot_address = object->address();
- Address end = object->address() + object->Size();
-
- while (slot_address < end) {
- HeapObject** slot = reinterpret_cast<HeapObject**>(slot_address);
- // When we are not in GC the Heap::InNewSpace() predicate
- // checks that pointers which satisfy predicate point into
- // the active semispace.
- Heap::InNewSpace(*slot);
- slot_address += kPointerSize;
- }
- }
- }
-}
-
-
void Heap::Verify() {
ASSERT(HasBeenSetup());
@@ -3328,24 +3373,15 @@
new_space_.Verify();
- VerifyPointersAndDirtyRegionsVisitor dirty_regions_visitor;
- old_pointer_space_->Verify(&dirty_regions_visitor);
- map_space_->Verify(&dirty_regions_visitor);
+ VerifyPointersAndRSetVisitor rset_visitor;
+ old_pointer_space_->Verify(&rset_visitor);
+ map_space_->Verify(&rset_visitor);
- VerifyPointersUnderWatermark(old_pointer_space_,
- &IteratePointersInDirtyRegion);
- VerifyPointersUnderWatermark(map_space_,
- &IteratePointersInDirtyMapsRegion);
- VerifyPointersUnderWatermark(lo_space_);
+ VerifyPointersVisitor no_rset_visitor;
+ old_data_space_->Verify(&no_rset_visitor);
+ code_space_->Verify(&no_rset_visitor);
+ cell_space_->Verify(&no_rset_visitor);
- VerifyPageWatermarkValidity(old_pointer_space_, ALL_INVALID);
- VerifyPageWatermarkValidity(map_space_, ALL_INVALID);
-
- VerifyPointersVisitor no_dirty_regions_visitor;
- old_data_space_->Verify(&no_dirty_regions_visitor);
- code_space_->Verify(&no_dirty_regions_visitor);
- cell_space_->Verify(&no_dirty_regions_visitor);
-
lo_space_->Verify();
}
#endif // DEBUG
@@ -3397,253 +3433,65 @@
#endif // DEBUG
-bool Heap::IteratePointersInDirtyRegion(Address start,
- Address end,
- ObjectSlotCallback copy_object_func) {
- Address slot_address = start;
- bool pointers_to_new_space_found = false;
+int Heap::IterateRSetRange(Address object_start,
+ Address object_end,
+ Address rset_start,
+ ObjectSlotCallback copy_object_func) {
+ Address object_address = object_start;
+ Address rset_address = rset_start;
+ int set_bits_count = 0;
- while (slot_address < end) {
- Object** slot = reinterpret_cast<Object**>(slot_address);
- if (Heap::InNewSpace(*slot)) {
- ASSERT((*slot)->IsHeapObject());
- copy_object_func(reinterpret_cast<HeapObject**>(slot));
- if (Heap::InNewSpace(*slot)) {
- ASSERT((*slot)->IsHeapObject());
- pointers_to_new_space_found = true;
+ // Loop over all the pointers in [object_start, object_end).
+ while (object_address < object_end) {
+ uint32_t rset_word = Memory::uint32_at(rset_address);
+ if (rset_word != 0) {
+ uint32_t result_rset = rset_word;
+ for (uint32_t bitmask = 1; bitmask != 0; bitmask = bitmask << 1) {
+ // Do not dereference pointers at or past object_end.
+ if ((rset_word & bitmask) != 0 && object_address < object_end) {
+ Object** object_p = reinterpret_cast<Object**>(object_address);
+ if (Heap::InNewSpace(*object_p)) {
+ copy_object_func(reinterpret_cast<HeapObject**>(object_p));
+ }
+ // If this pointer does not need to be remembered anymore, clear
+ // the remembered set bit.
+ if (!Heap::InNewSpace(*object_p)) result_rset &= ~bitmask;
+ set_bits_count++;
+ }
+ object_address += kPointerSize;
}
- }
- slot_address += kPointerSize;
- }
- return pointers_to_new_space_found;
-}
-
-
-// Compute start address of the first map following given addr.
-static inline Address MapStartAlign(Address addr) {
- Address page = Page::FromAddress(addr)->ObjectAreaStart();
- return page + (((addr - page) + (Map::kSize - 1)) / Map::kSize * Map::kSize);
-}
-
-
-// Compute end address of the first map preceding given addr.
-static inline Address MapEndAlign(Address addr) {
- Address page = Page::FromAllocationTop(addr)->ObjectAreaStart();
- return page + ((addr - page) / Map::kSize * Map::kSize);
-}
-
-
-static bool IteratePointersInDirtyMaps(Address start,
- Address end,
- ObjectSlotCallback copy_object_func) {
- ASSERT(MapStartAlign(start) == start);
- ASSERT(MapEndAlign(end) == end);
-
- Address map_address = start;
- bool pointers_to_new_space_found = false;
-
- while (map_address < end) {
- ASSERT(!Heap::InNewSpace(Memory::Object_at(map_address)));
- ASSERT(Memory::Object_at(map_address)->IsMap());
-
- Address pointer_fields_start = map_address + Map::kPointerFieldsBeginOffset;
- Address pointer_fields_end = map_address + Map::kPointerFieldsEndOffset;
-
- if (Heap::IteratePointersInDirtyRegion(pointer_fields_start,
- pointer_fields_end,
- copy_object_func)) {
- pointers_to_new_space_found = true;
- }
-
- map_address += Map::kSize;
- }
-
- return pointers_to_new_space_found;
-}
-
-
-bool Heap::IteratePointersInDirtyMapsRegion(
- Address start,
- Address end,
- ObjectSlotCallback copy_object_func) {
- Address map_aligned_start = MapStartAlign(start);
- Address map_aligned_end = MapEndAlign(end);
-
- bool contains_pointers_to_new_space = false;
-
- if (map_aligned_start != start) {
- Address prev_map = map_aligned_start - Map::kSize;
- ASSERT(Memory::Object_at(prev_map)->IsMap());
-
- Address pointer_fields_start =
- Max(start, prev_map + Map::kPointerFieldsBeginOffset);
-
- Address pointer_fields_end =
- Min(prev_map + Map::kCodeCacheOffset + kPointerSize, end);
-
- contains_pointers_to_new_space =
- IteratePointersInDirtyRegion(pointer_fields_start,
- pointer_fields_end,
- copy_object_func)
- || contains_pointers_to_new_space;
- }
-
- contains_pointers_to_new_space =
- IteratePointersInDirtyMaps(map_aligned_start,
- map_aligned_end,
- copy_object_func)
- || contains_pointers_to_new_space;
-
- if (map_aligned_end != end) {
- ASSERT(Memory::Object_at(map_aligned_end)->IsMap());
-
- Address pointer_fields_start = map_aligned_end + Map::kPrototypeOffset;
-
- Address pointer_fields_end =
- Min(end, map_aligned_end + Map::kCodeCacheOffset + kPointerSize);
-
- contains_pointers_to_new_space =
- IteratePointersInDirtyRegion(pointer_fields_start,
- pointer_fields_end,
- copy_object_func)
- || contains_pointers_to_new_space;
- }
-
- return contains_pointers_to_new_space;
-}
-
-
-void Heap::IterateAndMarkPointersToNewSpace(Address start,
- Address end,
- ObjectSlotCallback callback) {
- Address slot_address = start;
- Page* page = Page::FromAddress(start);
-
- uint32_t marks = page->GetRegionMarks();
-
- while (slot_address < end) {
- Object** slot = reinterpret_cast<Object**>(slot_address);
- if (Heap::InNewSpace(*slot)) {
- ASSERT((*slot)->IsHeapObject());
- callback(reinterpret_cast<HeapObject**>(slot));
- if (Heap::InNewSpace(*slot)) {
- ASSERT((*slot)->IsHeapObject());
- marks |= page->GetRegionMaskForAddress(slot_address);
+ // Update the remembered set if it has changed.
+ if (result_rset != rset_word) {
+ Memory::uint32_at(rset_address) = result_rset;
}
+ } else {
+ // No bits in the word were set. This is the common case.
+ object_address += kPointerSize * kBitsPerInt;
}
- slot_address += kPointerSize;
+ rset_address += kIntSize;
}
-
- page->SetRegionMarks(marks);
+ return set_bits_count;
}
-uint32_t Heap::IterateDirtyRegions(
- uint32_t marks,
- Address area_start,
- Address area_end,
- DirtyRegionCallback visit_dirty_region,
- ObjectSlotCallback copy_object_func) {
- uint32_t newmarks = 0;
- uint32_t mask = 1;
+void Heap::IterateRSet(PagedSpace* space, ObjectSlotCallback copy_object_func) {
+ ASSERT(Page::is_rset_in_use());
+ ASSERT(space == old_pointer_space_ || space == map_space_);
- if (area_start >= area_end) {
- return newmarks;
- }
+ static void* paged_rset_histogram = StatsTable::CreateHistogram(
+ "V8.RSetPaged",
+ 0,
+ Page::kObjectAreaSize / kPointerSize,
+ 30);
- Address region_start = area_start;
-
- // area_start does not necessarily coincide with start of the first region.
- // Thus to calculate the beginning of the next region we have to align
- // area_start by Page::kRegionSize.
- Address second_region =
- reinterpret_cast<Address>(
- reinterpret_cast<intptr_t>(area_start + Page::kRegionSize) &
- ~Page::kRegionAlignmentMask);
-
- // Next region might be beyond area_end.
- Address region_end = Min(second_region, area_end);
-
- if (marks & mask) {
- if (visit_dirty_region(region_start, region_end, copy_object_func)) {
- newmarks |= mask;
- }
- }
- mask <<= 1;
-
- // Iterate subsequent regions which fully lay inside [area_start, area_end[.
- region_start = region_end;
- region_end = region_start + Page::kRegionSize;
-
- while (region_end <= area_end) {
- if (marks & mask) {
- if (visit_dirty_region(region_start, region_end, copy_object_func)) {
- newmarks |= mask;
- }
- }
-
- region_start = region_end;
- region_end = region_start + Page::kRegionSize;
-
- mask <<= 1;
- }
-
- if (region_start != area_end) {
- // A small piece of area left uniterated because area_end does not coincide
- // with region end. Check whether region covering last part of area is
- // dirty.
- if (marks & mask) {
- if (visit_dirty_region(region_start, area_end, copy_object_func)) {
- newmarks |= mask;
- }
- }
- }
-
- return newmarks;
-}
-
-
-
-void Heap::IterateDirtyRegions(
- PagedSpace* space,
- DirtyRegionCallback visit_dirty_region,
- ObjectSlotCallback copy_object_func,
- ExpectedPageWatermarkState expected_page_watermark_state) {
-
PageIterator it(space, PageIterator::PAGES_IN_USE);
-
while (it.has_next()) {
Page* page = it.next();
- uint32_t marks = page->GetRegionMarks();
-
- if (marks != Page::kAllRegionsCleanMarks) {
- Address start = page->ObjectAreaStart();
-
- // Do not try to visit pointers beyond page allocation watermark.
- // Page can contain garbage pointers there.
- Address end;
-
- if ((expected_page_watermark_state == WATERMARK_SHOULD_BE_VALID) ||
- page->IsWatermarkValid()) {
- end = page->AllocationWatermark();
- } else {
- end = page->CachedAllocationWatermark();
- }
-
- ASSERT(space == old_pointer_space_ ||
- (space == map_space_ &&
- ((page->ObjectAreaStart() - end) % Map::kSize == 0)));
-
- page->SetRegionMarks(IterateDirtyRegions(marks,
- start,
- end,
- visit_dirty_region,
- copy_object_func));
+ int count = IterateRSetRange(page->ObjectAreaStart(), page->AllocationTop(),
+ page->RSetStart(), copy_object_func);
+ if (paged_rset_histogram != NULL) {
+ StatsTable::AddHistogramSample(paged_rset_histogram, count);
}
-
- // Mark page watermark as invalid to maintain watermark validity invariant.
- // See Page::FlipMeaningOfInvalidatedWatermarkFlag() for details.
- page->InvalidateWatermark(true);
}
}
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