| // 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. |
| |
| #ifndef V8_HEAP_SCAVENGER_H_ |
| #define V8_HEAP_SCAVENGER_H_ |
| |
| #include "src/heap/objects-visiting.h" |
| #include "src/heap/slot-set.h" |
| #include "src/heap/worklist.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| static const int kCopiedListSegmentSize = 64; |
| static const int kPromotionListSegmentSize = 64; |
| |
| using AddressRange = std::pair<Address, Address>; |
| using CopiedList = Worklist<AddressRange, kCopiedListSegmentSize>; |
| using ObjectAndSize = std::pair<HeapObject*, int>; |
| using PromotionList = Worklist<ObjectAndSize, kPromotionListSegmentSize>; |
| |
| // A list of copied ranges. Keeps the last consecutive range local and announces |
| // all other ranges to a global work list. |
| class CopiedRangesList { |
| public: |
| CopiedRangesList(CopiedList* copied_list, int task_id) |
| : current_start_(nullptr), |
| current_end_(nullptr), |
| copied_list_(copied_list, task_id) {} |
| |
| ~CopiedRangesList() { |
| CHECK_NULL(current_start_); |
| CHECK_NULL(current_end_); |
| } |
| |
| void Insert(HeapObject* object, int size) { |
| const Address object_address = object->address(); |
| if (current_end_ != object_address) { |
| if (current_start_ != nullptr) { |
| copied_list_.Push(AddressRange(current_start_, current_end_)); |
| } |
| current_start_ = object_address; |
| current_end_ = current_start_ + size; |
| return; |
| } |
| DCHECK_EQ(current_end_, object_address); |
| current_end_ += size; |
| return; |
| } |
| |
| bool Pop(AddressRange* entry) { |
| if (copied_list_.Pop(entry)) { |
| return true; |
| } else if (current_start_ != nullptr) { |
| *entry = AddressRange(current_start_, current_end_); |
| current_start_ = current_end_ = nullptr; |
| return true; |
| } |
| return false; |
| } |
| |
| private: |
| Address current_start_; |
| Address current_end_; |
| CopiedList::View copied_list_; |
| }; |
| |
| class Scavenger { |
| public: |
| Scavenger(Heap* heap, bool is_logging, bool is_incremental_marking, |
| CopiedList* copied_list, PromotionList* promotion_list, int task_id) |
| : heap_(heap), |
| promotion_list_(promotion_list, task_id), |
| copied_list_(copied_list, task_id), |
| is_logging_(is_logging), |
| is_incremental_marking_(is_incremental_marking) {} |
| |
| // Scavenges an object |object| referenced from slot |p|. |object| is required |
| // to be in from space. |
| inline void ScavengeObject(HeapObject** p, HeapObject* object); |
| |
| // Potentially scavenges an object referenced from |slot_address| if it is |
| // indeed a HeapObject and resides in from space. |
| inline SlotCallbackResult CheckAndScavengeObject(Heap* heap, |
| Address slot_address); |
| |
| // Processes remaining work (=objects) after single objects have been |
| // manually scavenged using ScavengeObject or CheckAndScavengeObject. |
| void Process(); |
| |
| private: |
| inline Heap* heap() { return heap_; } |
| |
| V8_INLINE HeapObject* MigrateObject(HeapObject* source, HeapObject* target, |
| int size); |
| |
| V8_INLINE bool SemiSpaceCopyObject(Map* map, HeapObject** slot, |
| HeapObject* object, int object_size); |
| |
| V8_INLINE bool PromoteObject(Map* map, HeapObject** slot, HeapObject* object, |
| int object_size); |
| |
| V8_INLINE void EvacuateObject(HeapObject** slot, Map* map, |
| HeapObject* source); |
| |
| // Different cases for object evacuation. |
| |
| V8_INLINE void EvacuateObjectDefault(Map* map, HeapObject** slot, |
| HeapObject* object, int object_size); |
| |
| V8_INLINE void EvacuateJSFunction(Map* map, HeapObject** slot, |
| JSFunction* object, int object_size); |
| |
| inline void EvacuateThinString(Map* map, HeapObject** slot, |
| ThinString* object, int object_size); |
| |
| inline void EvacuateShortcutCandidate(Map* map, HeapObject** slot, |
| ConsString* object, int object_size); |
| |
| void IterateAndScavengePromotedObject(HeapObject* target, int size); |
| |
| void RecordCopiedObject(HeapObject* obj); |
| |
| Heap* const heap_; |
| PromotionList::View promotion_list_; |
| CopiedRangesList copied_list_; |
| bool is_logging_; |
| bool is_incremental_marking_; |
| }; |
| |
| // Helper class for turning the scavenger into an object visitor that is also |
| // filtering out non-HeapObjects and objects which do not reside in new space. |
| class RootScavengeVisitor final : public RootVisitor { |
| public: |
| RootScavengeVisitor(Heap* heap, Scavenger* scavenger) |
| : heap_(heap), scavenger_(scavenger) {} |
| |
| void VisitRootPointer(Root root, Object** p) final; |
| void VisitRootPointers(Root root, Object** start, Object** end) final; |
| |
| private: |
| void ScavengePointer(Object** p); |
| |
| Heap* const heap_; |
| Scavenger* const scavenger_; |
| }; |
| |
| class ScavengeVisitor final : public NewSpaceVisitor<ScavengeVisitor> { |
| public: |
| ScavengeVisitor(Heap* heap, Scavenger* scavenger) |
| : heap_(heap), scavenger_(scavenger) {} |
| |
| V8_INLINE void VisitPointers(HeapObject* host, Object** start, |
| Object** end) final; |
| |
| private: |
| Heap* const heap_; |
| Scavenger* const scavenger_; |
| }; |
| |
| } // namespace internal |
| } // namespace v8 |
| |
| #endif // V8_HEAP_SCAVENGER_H_ |