| // Copyright 2015 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "src/heap/slots-buffer.h" |
| |
| #include "src/assembler.h" |
| #include "src/heap/heap.h" |
| #include "src/objects-inl.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| bool SlotsBuffer::IsTypedSlot(ObjectSlot slot) { |
| return reinterpret_cast<uintptr_t>(slot) < NUMBER_OF_SLOT_TYPES; |
| } |
| |
| |
| bool SlotsBuffer::AddTo(SlotsBufferAllocator* allocator, |
| SlotsBuffer** buffer_address, SlotType type, |
| Address addr, AdditionMode mode) { |
| SlotsBuffer* buffer = *buffer_address; |
| if (buffer == NULL || !buffer->HasSpaceForTypedSlot()) { |
| if (mode == FAIL_ON_OVERFLOW && ChainLengthThresholdReached(buffer)) { |
| allocator->DeallocateChain(buffer_address); |
| return false; |
| } |
| buffer = allocator->AllocateBuffer(buffer); |
| *buffer_address = buffer; |
| } |
| DCHECK(buffer->HasSpaceForTypedSlot()); |
| buffer->Add(reinterpret_cast<ObjectSlot>(type)); |
| buffer->Add(reinterpret_cast<ObjectSlot>(addr)); |
| return true; |
| } |
| |
| |
| void SlotsBuffer::RemoveInvalidSlots(Heap* heap, SlotsBuffer* buffer) { |
| // Remove entries by replacing them with an old-space slot containing a smi |
| // that is located in an unmovable page. |
| const ObjectSlot kRemovedEntry = HeapObject::RawField( |
| heap->empty_fixed_array(), FixedArrayBase::kLengthOffset); |
| DCHECK(Page::FromAddress(reinterpret_cast<Address>(kRemovedEntry)) |
| ->NeverEvacuate()); |
| |
| while (buffer != NULL) { |
| SlotsBuffer::ObjectSlot* slots = buffer->slots_; |
| intptr_t slots_count = buffer->idx_; |
| |
| for (int slot_idx = 0; slot_idx < slots_count; ++slot_idx) { |
| ObjectSlot slot = slots[slot_idx]; |
| if (!IsTypedSlot(slot)) { |
| Object* object = *slot; |
| // Slots are invalid when they currently: |
| // - do not point to a heap object (SMI) |
| // - point to a heap object in new space |
| // - are not within a live heap object on a valid pointer slot |
| // - point to a heap object not on an evacuation candidate |
| // TODO(mlippautz): Move InNewSpace check above IsSlotInLiveObject once |
| // we filter out unboxed double slots eagerly. |
| if (!object->IsHeapObject() || |
| !heap->mark_compact_collector()->IsSlotInLiveObject( |
| reinterpret_cast<Address>(slot)) || |
| heap->InNewSpace(object) || |
| !Page::FromAddress(reinterpret_cast<Address>(object)) |
| ->IsEvacuationCandidate()) { |
| // TODO(hpayer): Instead of replacing slots with kRemovedEntry we |
| // could shrink the slots buffer in-place. |
| slots[slot_idx] = kRemovedEntry; |
| } |
| } else { |
| ++slot_idx; |
| DCHECK(slot_idx < slots_count); |
| } |
| } |
| buffer = buffer->next(); |
| } |
| } |
| |
| |
| void SlotsBuffer::RemoveObjectSlots(Heap* heap, SlotsBuffer* buffer, |
| Address start_slot, Address end_slot) { |
| // Remove entries by replacing them with an old-space slot containing a smi |
| // that is located in an unmovable page. |
| const ObjectSlot kRemovedEntry = HeapObject::RawField( |
| heap->empty_fixed_array(), FixedArrayBase::kLengthOffset); |
| DCHECK(Page::FromAddress(reinterpret_cast<Address>(kRemovedEntry)) |
| ->NeverEvacuate()); |
| |
| while (buffer != NULL) { |
| SlotsBuffer::ObjectSlot* slots = buffer->slots_; |
| intptr_t slots_count = buffer->idx_; |
| bool is_typed_slot = false; |
| |
| for (int slot_idx = 0; slot_idx < slots_count; ++slot_idx) { |
| ObjectSlot slot = slots[slot_idx]; |
| if (!IsTypedSlot(slot)) { |
| Address slot_address = reinterpret_cast<Address>(slot); |
| if (slot_address >= start_slot && slot_address < end_slot) { |
| // TODO(hpayer): Instead of replacing slots with kRemovedEntry we |
| // could shrink the slots buffer in-place. |
| slots[slot_idx] = kRemovedEntry; |
| if (is_typed_slot) { |
| slots[slot_idx - 1] = kRemovedEntry; |
| } |
| } |
| is_typed_slot = false; |
| } else { |
| is_typed_slot = true; |
| DCHECK(slot_idx < slots_count); |
| } |
| } |
| buffer = buffer->next(); |
| } |
| } |
| |
| |
| void SlotsBuffer::VerifySlots(Heap* heap, SlotsBuffer* buffer) { |
| while (buffer != NULL) { |
| SlotsBuffer::ObjectSlot* slots = buffer->slots_; |
| intptr_t slots_count = buffer->idx_; |
| |
| for (int slot_idx = 0; slot_idx < slots_count; ++slot_idx) { |
| ObjectSlot slot = slots[slot_idx]; |
| if (!IsTypedSlot(slot)) { |
| Object* object = *slot; |
| if (object->IsHeapObject()) { |
| HeapObject* heap_object = HeapObject::cast(object); |
| CHECK(!heap->InNewSpace(object)); |
| heap->mark_compact_collector()->VerifyIsSlotInLiveObject( |
| reinterpret_cast<Address>(slot), heap_object); |
| } |
| } else { |
| ++slot_idx; |
| DCHECK(slot_idx < slots_count); |
| } |
| } |
| buffer = buffer->next(); |
| } |
| } |
| |
| |
| SlotsBuffer* SlotsBufferAllocator::AllocateBuffer(SlotsBuffer* next_buffer) { |
| return new SlotsBuffer(next_buffer); |
| } |
| |
| |
| void SlotsBufferAllocator::DeallocateBuffer(SlotsBuffer* buffer) { |
| delete buffer; |
| } |
| |
| |
| void SlotsBufferAllocator::DeallocateChain(SlotsBuffer** buffer_address) { |
| SlotsBuffer* buffer = *buffer_address; |
| while (buffer != NULL) { |
| SlotsBuffer* next_buffer = buffer->next(); |
| DeallocateBuffer(buffer); |
| buffer = next_buffer; |
| } |
| *buffer_address = NULL; |
| } |
| |
| } // namespace internal |
| } // namespace v8 |