Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame^] | 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. |
| 4 | |
| 5 | #include "src/v8.h" |
| 6 | |
| 7 | #include "src/heap/objects-visiting.h" |
| 8 | |
| 9 | namespace v8 { |
| 10 | namespace internal { |
| 11 | |
| 12 | |
| 13 | StaticVisitorBase::VisitorId StaticVisitorBase::GetVisitorId( |
| 14 | int instance_type, int instance_size) { |
| 15 | if (instance_type < FIRST_NONSTRING_TYPE) { |
| 16 | switch (instance_type & kStringRepresentationMask) { |
| 17 | case kSeqStringTag: |
| 18 | if ((instance_type & kStringEncodingMask) == kOneByteStringTag) { |
| 19 | return kVisitSeqOneByteString; |
| 20 | } else { |
| 21 | return kVisitSeqTwoByteString; |
| 22 | } |
| 23 | |
| 24 | case kConsStringTag: |
| 25 | if (IsShortcutCandidate(instance_type)) { |
| 26 | return kVisitShortcutCandidate; |
| 27 | } else { |
| 28 | return kVisitConsString; |
| 29 | } |
| 30 | |
| 31 | case kSlicedStringTag: |
| 32 | return kVisitSlicedString; |
| 33 | |
| 34 | case kExternalStringTag: |
| 35 | return GetVisitorIdForSize(kVisitDataObject, kVisitDataObjectGeneric, |
| 36 | instance_size); |
| 37 | } |
| 38 | UNREACHABLE(); |
| 39 | } |
| 40 | |
| 41 | switch (instance_type) { |
| 42 | case BYTE_ARRAY_TYPE: |
| 43 | return kVisitByteArray; |
| 44 | |
| 45 | case FREE_SPACE_TYPE: |
| 46 | return kVisitFreeSpace; |
| 47 | |
| 48 | case FIXED_ARRAY_TYPE: |
| 49 | return kVisitFixedArray; |
| 50 | |
| 51 | case FIXED_DOUBLE_ARRAY_TYPE: |
| 52 | return kVisitFixedDoubleArray; |
| 53 | |
| 54 | case CONSTANT_POOL_ARRAY_TYPE: |
| 55 | return kVisitConstantPoolArray; |
| 56 | |
| 57 | case ODDBALL_TYPE: |
| 58 | return kVisitOddball; |
| 59 | |
| 60 | case MAP_TYPE: |
| 61 | return kVisitMap; |
| 62 | |
| 63 | case CODE_TYPE: |
| 64 | return kVisitCode; |
| 65 | |
| 66 | case CELL_TYPE: |
| 67 | return kVisitCell; |
| 68 | |
| 69 | case PROPERTY_CELL_TYPE: |
| 70 | return kVisitPropertyCell; |
| 71 | |
| 72 | case JS_SET_TYPE: |
| 73 | return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric, |
| 74 | JSSet::kSize); |
| 75 | |
| 76 | case JS_MAP_TYPE: |
| 77 | return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric, |
| 78 | JSMap::kSize); |
| 79 | |
| 80 | case JS_WEAK_MAP_TYPE: |
| 81 | case JS_WEAK_SET_TYPE: |
| 82 | return kVisitJSWeakCollection; |
| 83 | |
| 84 | case JS_REGEXP_TYPE: |
| 85 | return kVisitJSRegExp; |
| 86 | |
| 87 | case SHARED_FUNCTION_INFO_TYPE: |
| 88 | return kVisitSharedFunctionInfo; |
| 89 | |
| 90 | case JS_PROXY_TYPE: |
| 91 | return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric, |
| 92 | JSProxy::kSize); |
| 93 | |
| 94 | case JS_FUNCTION_PROXY_TYPE: |
| 95 | return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric, |
| 96 | JSFunctionProxy::kSize); |
| 97 | |
| 98 | case FOREIGN_TYPE: |
| 99 | return GetVisitorIdForSize(kVisitDataObject, kVisitDataObjectGeneric, |
| 100 | Foreign::kSize); |
| 101 | |
| 102 | case SYMBOL_TYPE: |
| 103 | return kVisitSymbol; |
| 104 | |
| 105 | case FILLER_TYPE: |
| 106 | return kVisitDataObjectGeneric; |
| 107 | |
| 108 | case JS_ARRAY_BUFFER_TYPE: |
| 109 | return kVisitJSArrayBuffer; |
| 110 | |
| 111 | case JS_TYPED_ARRAY_TYPE: |
| 112 | return kVisitJSTypedArray; |
| 113 | |
| 114 | case JS_DATA_VIEW_TYPE: |
| 115 | return kVisitJSDataView; |
| 116 | |
| 117 | case JS_OBJECT_TYPE: |
| 118 | case JS_CONTEXT_EXTENSION_OBJECT_TYPE: |
| 119 | case JS_GENERATOR_OBJECT_TYPE: |
| 120 | case JS_MODULE_TYPE: |
| 121 | case JS_VALUE_TYPE: |
| 122 | case JS_DATE_TYPE: |
| 123 | case JS_ARRAY_TYPE: |
| 124 | case JS_GLOBAL_PROXY_TYPE: |
| 125 | case JS_GLOBAL_OBJECT_TYPE: |
| 126 | case JS_BUILTINS_OBJECT_TYPE: |
| 127 | case JS_MESSAGE_OBJECT_TYPE: |
| 128 | case JS_SET_ITERATOR_TYPE: |
| 129 | case JS_MAP_ITERATOR_TYPE: |
| 130 | return GetVisitorIdForSize(kVisitJSObject, kVisitJSObjectGeneric, |
| 131 | instance_size); |
| 132 | |
| 133 | case JS_FUNCTION_TYPE: |
| 134 | return kVisitJSFunction; |
| 135 | |
| 136 | case HEAP_NUMBER_TYPE: |
| 137 | case MUTABLE_HEAP_NUMBER_TYPE: |
| 138 | #define EXTERNAL_ARRAY_CASE(Type, type, TYPE, ctype, size) \ |
| 139 | case EXTERNAL_##TYPE##_ARRAY_TYPE: |
| 140 | |
| 141 | TYPED_ARRAYS(EXTERNAL_ARRAY_CASE) |
| 142 | return GetVisitorIdForSize(kVisitDataObject, kVisitDataObjectGeneric, |
| 143 | instance_size); |
| 144 | #undef EXTERNAL_ARRAY_CASE |
| 145 | |
| 146 | case FIXED_UINT8_ARRAY_TYPE: |
| 147 | case FIXED_INT8_ARRAY_TYPE: |
| 148 | case FIXED_UINT16_ARRAY_TYPE: |
| 149 | case FIXED_INT16_ARRAY_TYPE: |
| 150 | case FIXED_UINT32_ARRAY_TYPE: |
| 151 | case FIXED_INT32_ARRAY_TYPE: |
| 152 | case FIXED_FLOAT32_ARRAY_TYPE: |
| 153 | case FIXED_UINT8_CLAMPED_ARRAY_TYPE: |
| 154 | return kVisitFixedTypedArray; |
| 155 | |
| 156 | case FIXED_FLOAT64_ARRAY_TYPE: |
| 157 | return kVisitFixedFloat64Array; |
| 158 | |
| 159 | #define MAKE_STRUCT_CASE(NAME, Name, name) case NAME##_TYPE: |
| 160 | STRUCT_LIST(MAKE_STRUCT_CASE) |
| 161 | #undef MAKE_STRUCT_CASE |
| 162 | if (instance_type == ALLOCATION_SITE_TYPE) { |
| 163 | return kVisitAllocationSite; |
| 164 | } |
| 165 | |
| 166 | return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric, |
| 167 | instance_size); |
| 168 | |
| 169 | default: |
| 170 | UNREACHABLE(); |
| 171 | return kVisitorIdCount; |
| 172 | } |
| 173 | } |
| 174 | |
| 175 | |
| 176 | // We don't record weak slots during marking or scavenges. Instead we do it |
| 177 | // once when we complete mark-compact cycle. Note that write barrier has no |
| 178 | // effect if we are already in the middle of compacting mark-sweep cycle and we |
| 179 | // have to record slots manually. |
| 180 | static bool MustRecordSlots(Heap* heap) { |
| 181 | return heap->gc_state() == Heap::MARK_COMPACT && |
| 182 | heap->mark_compact_collector()->is_compacting(); |
| 183 | } |
| 184 | |
| 185 | |
| 186 | template <class T> |
| 187 | struct WeakListVisitor; |
| 188 | |
| 189 | |
| 190 | template <class T> |
| 191 | Object* VisitWeakList(Heap* heap, Object* list, WeakObjectRetainer* retainer) { |
| 192 | Object* undefined = heap->undefined_value(); |
| 193 | Object* head = undefined; |
| 194 | T* tail = NULL; |
| 195 | MarkCompactCollector* collector = heap->mark_compact_collector(); |
| 196 | bool record_slots = MustRecordSlots(heap); |
| 197 | while (list != undefined) { |
| 198 | // Check whether to keep the candidate in the list. |
| 199 | T* candidate = reinterpret_cast<T*>(list); |
| 200 | Object* retained = retainer->RetainAs(list); |
| 201 | if (retained != NULL) { |
| 202 | if (head == undefined) { |
| 203 | // First element in the list. |
| 204 | head = retained; |
| 205 | } else { |
| 206 | // Subsequent elements in the list. |
| 207 | DCHECK(tail != NULL); |
| 208 | WeakListVisitor<T>::SetWeakNext(tail, retained); |
| 209 | if (record_slots) { |
| 210 | Object** next_slot = |
| 211 | HeapObject::RawField(tail, WeakListVisitor<T>::WeakNextOffset()); |
| 212 | collector->RecordSlot(next_slot, next_slot, retained); |
| 213 | } |
| 214 | } |
| 215 | // Retained object is new tail. |
| 216 | DCHECK(!retained->IsUndefined()); |
| 217 | candidate = reinterpret_cast<T*>(retained); |
| 218 | tail = candidate; |
| 219 | |
| 220 | |
| 221 | // tail is a live object, visit it. |
| 222 | WeakListVisitor<T>::VisitLiveObject(heap, tail, retainer); |
| 223 | } else { |
| 224 | WeakListVisitor<T>::VisitPhantomObject(heap, candidate); |
| 225 | } |
| 226 | |
| 227 | // Move to next element in the list. |
| 228 | list = WeakListVisitor<T>::WeakNext(candidate); |
| 229 | } |
| 230 | |
| 231 | // Terminate the list if there is one or more elements. |
| 232 | if (tail != NULL) { |
| 233 | WeakListVisitor<T>::SetWeakNext(tail, undefined); |
| 234 | } |
| 235 | return head; |
| 236 | } |
| 237 | |
| 238 | |
| 239 | template <class T> |
| 240 | static void ClearWeakList(Heap* heap, Object* list) { |
| 241 | Object* undefined = heap->undefined_value(); |
| 242 | while (list != undefined) { |
| 243 | T* candidate = reinterpret_cast<T*>(list); |
| 244 | list = WeakListVisitor<T>::WeakNext(candidate); |
| 245 | WeakListVisitor<T>::SetWeakNext(candidate, undefined); |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | |
| 250 | template <> |
| 251 | struct WeakListVisitor<JSFunction> { |
| 252 | static void SetWeakNext(JSFunction* function, Object* next) { |
| 253 | function->set_next_function_link(next); |
| 254 | } |
| 255 | |
| 256 | static Object* WeakNext(JSFunction* function) { |
| 257 | return function->next_function_link(); |
| 258 | } |
| 259 | |
| 260 | static int WeakNextOffset() { return JSFunction::kNextFunctionLinkOffset; } |
| 261 | |
| 262 | static void VisitLiveObject(Heap*, JSFunction*, WeakObjectRetainer*) {} |
| 263 | |
| 264 | static void VisitPhantomObject(Heap*, JSFunction*) {} |
| 265 | }; |
| 266 | |
| 267 | |
| 268 | template <> |
| 269 | struct WeakListVisitor<Code> { |
| 270 | static void SetWeakNext(Code* code, Object* next) { |
| 271 | code->set_next_code_link(next); |
| 272 | } |
| 273 | |
| 274 | static Object* WeakNext(Code* code) { return code->next_code_link(); } |
| 275 | |
| 276 | static int WeakNextOffset() { return Code::kNextCodeLinkOffset; } |
| 277 | |
| 278 | static void VisitLiveObject(Heap*, Code*, WeakObjectRetainer*) {} |
| 279 | |
| 280 | static void VisitPhantomObject(Heap*, Code*) {} |
| 281 | }; |
| 282 | |
| 283 | |
| 284 | template <> |
| 285 | struct WeakListVisitor<Context> { |
| 286 | static void SetWeakNext(Context* context, Object* next) { |
| 287 | context->set(Context::NEXT_CONTEXT_LINK, next, UPDATE_WRITE_BARRIER); |
| 288 | } |
| 289 | |
| 290 | static Object* WeakNext(Context* context) { |
| 291 | return context->get(Context::NEXT_CONTEXT_LINK); |
| 292 | } |
| 293 | |
| 294 | static int WeakNextOffset() { |
| 295 | return FixedArray::SizeFor(Context::NEXT_CONTEXT_LINK); |
| 296 | } |
| 297 | |
| 298 | static void VisitLiveObject(Heap* heap, Context* context, |
| 299 | WeakObjectRetainer* retainer) { |
| 300 | // Process the three weak lists linked off the context. |
| 301 | DoWeakList<JSFunction>(heap, context, retainer, |
| 302 | Context::OPTIMIZED_FUNCTIONS_LIST); |
| 303 | DoWeakList<Code>(heap, context, retainer, Context::OPTIMIZED_CODE_LIST); |
| 304 | DoWeakList<Code>(heap, context, retainer, Context::DEOPTIMIZED_CODE_LIST); |
| 305 | } |
| 306 | |
| 307 | template <class T> |
| 308 | static void DoWeakList(Heap* heap, Context* context, |
| 309 | WeakObjectRetainer* retainer, int index) { |
| 310 | // Visit the weak list, removing dead intermediate elements. |
| 311 | Object* list_head = VisitWeakList<T>(heap, context->get(index), retainer); |
| 312 | |
| 313 | // Update the list head. |
| 314 | context->set(index, list_head, UPDATE_WRITE_BARRIER); |
| 315 | |
| 316 | if (MustRecordSlots(heap)) { |
| 317 | // Record the updated slot if necessary. |
| 318 | Object** head_slot = |
| 319 | HeapObject::RawField(context, FixedArray::SizeFor(index)); |
| 320 | heap->mark_compact_collector()->RecordSlot(head_slot, head_slot, |
| 321 | list_head); |
| 322 | } |
| 323 | } |
| 324 | |
| 325 | static void VisitPhantomObject(Heap* heap, Context* context) { |
| 326 | ClearWeakList<JSFunction>(heap, |
| 327 | context->get(Context::OPTIMIZED_FUNCTIONS_LIST)); |
| 328 | ClearWeakList<Code>(heap, context->get(Context::OPTIMIZED_CODE_LIST)); |
| 329 | ClearWeakList<Code>(heap, context->get(Context::DEOPTIMIZED_CODE_LIST)); |
| 330 | } |
| 331 | }; |
| 332 | |
| 333 | |
| 334 | template <> |
| 335 | struct WeakListVisitor<JSArrayBufferView> { |
| 336 | static void SetWeakNext(JSArrayBufferView* obj, Object* next) { |
| 337 | obj->set_weak_next(next); |
| 338 | } |
| 339 | |
| 340 | static Object* WeakNext(JSArrayBufferView* obj) { return obj->weak_next(); } |
| 341 | |
| 342 | static int WeakNextOffset() { return JSArrayBufferView::kWeakNextOffset; } |
| 343 | |
| 344 | static void VisitLiveObject(Heap*, JSArrayBufferView*, WeakObjectRetainer*) {} |
| 345 | |
| 346 | static void VisitPhantomObject(Heap*, JSArrayBufferView*) {} |
| 347 | }; |
| 348 | |
| 349 | |
| 350 | template <> |
| 351 | struct WeakListVisitor<JSArrayBuffer> { |
| 352 | static void SetWeakNext(JSArrayBuffer* obj, Object* next) { |
| 353 | obj->set_weak_next(next); |
| 354 | } |
| 355 | |
| 356 | static Object* WeakNext(JSArrayBuffer* obj) { return obj->weak_next(); } |
| 357 | |
| 358 | static int WeakNextOffset() { return JSArrayBuffer::kWeakNextOffset; } |
| 359 | |
| 360 | static void VisitLiveObject(Heap* heap, JSArrayBuffer* array_buffer, |
| 361 | WeakObjectRetainer* retainer) { |
| 362 | Object* typed_array_obj = VisitWeakList<JSArrayBufferView>( |
| 363 | heap, array_buffer->weak_first_view(), retainer); |
| 364 | array_buffer->set_weak_first_view(typed_array_obj); |
| 365 | if (typed_array_obj != heap->undefined_value() && MustRecordSlots(heap)) { |
| 366 | Object** slot = HeapObject::RawField(array_buffer, |
| 367 | JSArrayBuffer::kWeakFirstViewOffset); |
| 368 | heap->mark_compact_collector()->RecordSlot(slot, slot, typed_array_obj); |
| 369 | } |
| 370 | } |
| 371 | |
| 372 | static void VisitPhantomObject(Heap* heap, JSArrayBuffer* phantom) { |
| 373 | Runtime::FreeArrayBuffer(heap->isolate(), phantom); |
| 374 | } |
| 375 | }; |
| 376 | |
| 377 | |
| 378 | template <> |
| 379 | struct WeakListVisitor<AllocationSite> { |
| 380 | static void SetWeakNext(AllocationSite* obj, Object* next) { |
| 381 | obj->set_weak_next(next); |
| 382 | } |
| 383 | |
| 384 | static Object* WeakNext(AllocationSite* obj) { return obj->weak_next(); } |
| 385 | |
| 386 | static int WeakNextOffset() { return AllocationSite::kWeakNextOffset; } |
| 387 | |
| 388 | static void VisitLiveObject(Heap*, AllocationSite*, WeakObjectRetainer*) {} |
| 389 | |
| 390 | static void VisitPhantomObject(Heap*, AllocationSite*) {} |
| 391 | }; |
| 392 | |
| 393 | |
| 394 | template Object* VisitWeakList<Code>(Heap* heap, Object* list, |
| 395 | WeakObjectRetainer* retainer); |
| 396 | |
| 397 | |
| 398 | template Object* VisitWeakList<JSFunction>(Heap* heap, Object* list, |
| 399 | WeakObjectRetainer* retainer); |
| 400 | |
| 401 | |
| 402 | template Object* VisitWeakList<Context>(Heap* heap, Object* list, |
| 403 | WeakObjectRetainer* retainer); |
| 404 | |
| 405 | |
| 406 | template Object* VisitWeakList<JSArrayBuffer>(Heap* heap, Object* list, |
| 407 | WeakObjectRetainer* retainer); |
| 408 | |
| 409 | |
| 410 | template Object* VisitWeakList<AllocationSite>(Heap* heap, Object* list, |
| 411 | WeakObjectRetainer* retainer); |
| 412 | } |
| 413 | } // namespace v8::internal |