1 // Copyright 2011 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
7 #include "src/heap/objects-visiting.h"
13 StaticVisitorBase::VisitorId StaticVisitorBase::GetVisitorId(
14 int instance_type, int instance_size, bool has_unboxed_fields) {
15 if (instance_type < FIRST_NONSTRING_TYPE) {
16 switch (instance_type & kStringRepresentationMask) {
18 if ((instance_type & kStringEncodingMask) == kOneByteStringTag) {
19 return kVisitSeqOneByteString;
21 return kVisitSeqTwoByteString;
25 if (IsShortcutCandidate(instance_type)) {
26 return kVisitShortcutCandidate;
28 return kVisitConsString;
31 case kSlicedStringTag:
32 return kVisitSlicedString;
34 case kExternalStringTag:
35 return GetVisitorIdForSize(kVisitDataObject, kVisitDataObjectGeneric,
36 instance_size, has_unboxed_fields);
41 switch (instance_type) {
43 return kVisitByteArray;
46 return kVisitFreeSpace;
48 case FIXED_ARRAY_TYPE:
49 return kVisitFixedArray;
51 case FIXED_DOUBLE_ARRAY_TYPE:
52 return kVisitFixedDoubleArray;
54 case CONSTANT_POOL_ARRAY_TYPE:
55 return kVisitConstantPoolArray;
69 case PROPERTY_CELL_TYPE:
70 return kVisitPropertyCell;
73 return kVisitWeakCell;
76 return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric,
77 JSSet::kSize, has_unboxed_fields);
80 return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric,
81 JSMap::kSize, has_unboxed_fields);
83 case JS_WEAK_MAP_TYPE:
84 case JS_WEAK_SET_TYPE:
85 return kVisitJSWeakCollection;
88 return kVisitJSRegExp;
90 case SHARED_FUNCTION_INFO_TYPE:
91 return kVisitSharedFunctionInfo;
94 return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric,
95 JSProxy::kSize, has_unboxed_fields);
97 case JS_FUNCTION_PROXY_TYPE:
98 return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric,
99 JSFunctionProxy::kSize, has_unboxed_fields);
102 return GetVisitorIdForSize(kVisitDataObject, kVisitDataObjectGeneric,
103 Foreign::kSize, has_unboxed_fields);
109 return kVisitDataObjectGeneric;
111 case JS_ARRAY_BUFFER_TYPE:
112 return kVisitJSArrayBuffer;
114 case JS_TYPED_ARRAY_TYPE:
115 return kVisitJSTypedArray;
117 case JS_DATA_VIEW_TYPE:
118 return kVisitJSDataView;
121 case JS_CONTEXT_EXTENSION_OBJECT_TYPE:
122 case JS_GENERATOR_OBJECT_TYPE:
127 case JS_GLOBAL_PROXY_TYPE:
128 case JS_GLOBAL_OBJECT_TYPE:
129 case JS_BUILTINS_OBJECT_TYPE:
130 case JS_MESSAGE_OBJECT_TYPE:
131 case JS_SET_ITERATOR_TYPE:
132 case JS_MAP_ITERATOR_TYPE:
133 return GetVisitorIdForSize(kVisitJSObject, kVisitJSObjectGeneric,
134 instance_size, has_unboxed_fields);
136 case JS_FUNCTION_TYPE:
137 return kVisitJSFunction;
139 case HEAP_NUMBER_TYPE:
140 case MUTABLE_HEAP_NUMBER_TYPE:
141 #define EXTERNAL_ARRAY_CASE(Type, type, TYPE, ctype, size) \
142 case EXTERNAL_##TYPE##_ARRAY_TYPE:
144 TYPED_ARRAYS(EXTERNAL_ARRAY_CASE)
145 return GetVisitorIdForSize(kVisitDataObject, kVisitDataObjectGeneric,
146 instance_size, has_unboxed_fields);
147 #undef EXTERNAL_ARRAY_CASE
149 case FIXED_UINT8_ARRAY_TYPE:
150 case FIXED_INT8_ARRAY_TYPE:
151 case FIXED_UINT16_ARRAY_TYPE:
152 case FIXED_INT16_ARRAY_TYPE:
153 case FIXED_UINT32_ARRAY_TYPE:
154 case FIXED_INT32_ARRAY_TYPE:
155 case FIXED_FLOAT32_ARRAY_TYPE:
156 case FIXED_UINT8_CLAMPED_ARRAY_TYPE:
157 return kVisitFixedTypedArray;
159 case FIXED_FLOAT64_ARRAY_TYPE:
160 return kVisitFixedFloat64Array;
162 #define MAKE_STRUCT_CASE(NAME, Name, name) case NAME##_TYPE:
163 STRUCT_LIST(MAKE_STRUCT_CASE)
164 #undef MAKE_STRUCT_CASE
165 if (instance_type == ALLOCATION_SITE_TYPE) {
166 return kVisitAllocationSite;
169 return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric,
170 instance_size, has_unboxed_fields);
174 return kVisitorIdCount;
179 // We don't record weak slots during marking or scavenges. Instead we do it
180 // once when we complete mark-compact cycle. Note that write barrier has no
181 // effect if we are already in the middle of compacting mark-sweep cycle and we
182 // have to record slots manually.
183 static bool MustRecordSlots(Heap* heap) {
184 return heap->gc_state() == Heap::MARK_COMPACT &&
185 heap->mark_compact_collector()->is_compacting();
190 struct WeakListVisitor;
194 Object* VisitWeakList(Heap* heap, Object* list, WeakObjectRetainer* retainer) {
195 Object* undefined = heap->undefined_value();
196 Object* head = undefined;
198 MarkCompactCollector* collector = heap->mark_compact_collector();
199 bool record_slots = MustRecordSlots(heap);
200 while (list != undefined) {
201 // Check whether to keep the candidate in the list.
202 T* candidate = reinterpret_cast<T*>(list);
203 Object* retained = retainer->RetainAs(list);
204 if (retained != NULL) {
205 if (head == undefined) {
206 // First element in the list.
209 // Subsequent elements in the list.
210 DCHECK(tail != NULL);
211 WeakListVisitor<T>::SetWeakNext(tail, retained);
214 HeapObject::RawField(tail, WeakListVisitor<T>::WeakNextOffset());
215 collector->RecordSlot(next_slot, next_slot, retained);
218 // Retained object is new tail.
219 DCHECK(!retained->IsUndefined());
220 candidate = reinterpret_cast<T*>(retained);
224 // tail is a live object, visit it.
225 WeakListVisitor<T>::VisitLiveObject(heap, tail, retainer);
227 WeakListVisitor<T>::VisitPhantomObject(heap, candidate);
230 // Move to next element in the list.
231 list = WeakListVisitor<T>::WeakNext(candidate);
234 // Terminate the list if there is one or more elements.
236 WeakListVisitor<T>::SetWeakNext(tail, undefined);
243 static void ClearWeakList(Heap* heap, Object* list) {
244 Object* undefined = heap->undefined_value();
245 while (list != undefined) {
246 T* candidate = reinterpret_cast<T*>(list);
247 list = WeakListVisitor<T>::WeakNext(candidate);
248 WeakListVisitor<T>::SetWeakNext(candidate, undefined);
254 struct WeakListVisitor<JSFunction> {
255 static void SetWeakNext(JSFunction* function, Object* next) {
256 function->set_next_function_link(next);
259 static Object* WeakNext(JSFunction* function) {
260 return function->next_function_link();
263 static int WeakNextOffset() { return JSFunction::kNextFunctionLinkOffset; }
265 static void VisitLiveObject(Heap*, JSFunction*, WeakObjectRetainer*) {}
267 static void VisitPhantomObject(Heap*, JSFunction*) {}
272 struct WeakListVisitor<Code> {
273 static void SetWeakNext(Code* code, Object* next) {
274 code->set_next_code_link(next);
277 static Object* WeakNext(Code* code) { return code->next_code_link(); }
279 static int WeakNextOffset() { return Code::kNextCodeLinkOffset; }
281 static void VisitLiveObject(Heap*, Code*, WeakObjectRetainer*) {}
283 static void VisitPhantomObject(Heap*, Code*) {}
288 struct WeakListVisitor<Context> {
289 static void SetWeakNext(Context* context, Object* next) {
290 context->set(Context::NEXT_CONTEXT_LINK, next, UPDATE_WRITE_BARRIER);
293 static Object* WeakNext(Context* context) {
294 return context->get(Context::NEXT_CONTEXT_LINK);
297 static int WeakNextOffset() {
298 return FixedArray::SizeFor(Context::NEXT_CONTEXT_LINK);
301 static void VisitLiveObject(Heap* heap, Context* context,
302 WeakObjectRetainer* retainer) {
303 // Process the three weak lists linked off the context.
304 DoWeakList<JSFunction>(heap, context, retainer,
305 Context::OPTIMIZED_FUNCTIONS_LIST);
307 // Code objects are always allocated in Code space, we do not have to visit
308 // them during scavenges.
309 if (heap->gc_state() == Heap::MARK_COMPACT) {
310 DoWeakList<Code>(heap, context, retainer, Context::OPTIMIZED_CODE_LIST);
311 DoWeakList<Code>(heap, context, retainer, Context::DEOPTIMIZED_CODE_LIST);
316 static void DoWeakList(Heap* heap, Context* context,
317 WeakObjectRetainer* retainer, int index) {
318 // Visit the weak list, removing dead intermediate elements.
319 Object* list_head = VisitWeakList<T>(heap, context->get(index), retainer);
321 // Update the list head.
322 context->set(index, list_head, UPDATE_WRITE_BARRIER);
324 if (MustRecordSlots(heap)) {
325 // Record the updated slot if necessary.
327 HeapObject::RawField(context, FixedArray::SizeFor(index));
328 heap->mark_compact_collector()->RecordSlot(head_slot, head_slot,
333 static void VisitPhantomObject(Heap* heap, Context* context) {
334 ClearWeakList<JSFunction>(heap,
335 context->get(Context::OPTIMIZED_FUNCTIONS_LIST));
336 ClearWeakList<Code>(heap, context->get(Context::OPTIMIZED_CODE_LIST));
337 ClearWeakList<Code>(heap, context->get(Context::DEOPTIMIZED_CODE_LIST));
343 struct WeakListVisitor<JSArrayBufferView> {
344 static void SetWeakNext(JSArrayBufferView* obj, Object* next) {
345 obj->set_weak_next(next);
348 static Object* WeakNext(JSArrayBufferView* obj) { return obj->weak_next(); }
350 static int WeakNextOffset() { return JSArrayBufferView::kWeakNextOffset; }
352 static void VisitLiveObject(Heap*, JSArrayBufferView*, WeakObjectRetainer*) {}
354 static void VisitPhantomObject(Heap*, JSArrayBufferView*) {}
359 struct WeakListVisitor<JSArrayBuffer> {
360 static void SetWeakNext(JSArrayBuffer* obj, Object* next) {
361 obj->set_weak_next(next);
364 static Object* WeakNext(JSArrayBuffer* obj) { return obj->weak_next(); }
366 static int WeakNextOffset() { return JSArrayBuffer::kWeakNextOffset; }
368 static void VisitLiveObject(Heap* heap, JSArrayBuffer* array_buffer,
369 WeakObjectRetainer* retainer) {
370 Object* typed_array_obj = VisitWeakList<JSArrayBufferView>(
371 heap, array_buffer->weak_first_view(), retainer);
372 array_buffer->set_weak_first_view(typed_array_obj);
373 if (typed_array_obj != heap->undefined_value() && MustRecordSlots(heap)) {
374 Object** slot = HeapObject::RawField(array_buffer,
375 JSArrayBuffer::kWeakFirstViewOffset);
376 heap->mark_compact_collector()->RecordSlot(slot, slot, typed_array_obj);
380 static void VisitPhantomObject(Heap* heap, JSArrayBuffer* phantom) {
381 Runtime::FreeArrayBuffer(heap->isolate(), phantom);
387 struct WeakListVisitor<AllocationSite> {
388 static void SetWeakNext(AllocationSite* obj, Object* next) {
389 obj->set_weak_next(next);
392 static Object* WeakNext(AllocationSite* obj) { return obj->weak_next(); }
394 static int WeakNextOffset() { return AllocationSite::kWeakNextOffset; }
396 static void VisitLiveObject(Heap*, AllocationSite*, WeakObjectRetainer*) {}
398 static void VisitPhantomObject(Heap*, AllocationSite*) {}
402 template Object* VisitWeakList<Code>(Heap* heap, Object* list,
403 WeakObjectRetainer* retainer);
406 template Object* VisitWeakList<JSFunction>(Heap* heap, Object* list,
407 WeakObjectRetainer* retainer);
410 template Object* VisitWeakList<Context>(Heap* heap, Object* list,
411 WeakObjectRetainer* retainer);
414 template Object* VisitWeakList<JSArrayBuffer>(Heap* heap, Object* list,
415 WeakObjectRetainer* retainer);
418 template Object* VisitWeakList<AllocationSite>(Heap* heap, Object* list,
419 WeakObjectRetainer* retainer);
421 } // namespace v8::internal