Line data Source code
1 : // Copyright 2018 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 : #ifndef V8_ROOTS_H_
6 : #define V8_ROOTS_H_
7 :
8 : #include "src/accessors.h"
9 : #include "src/globals.h"
10 : #include "src/heap-symbols.h"
11 : #include "src/objects-definitions.h"
12 : #include "src/objects.h"
13 : #include "src/objects/slots.h"
14 :
15 : namespace v8 {
16 : namespace internal {
17 :
18 : // Forward declarations.
19 : enum ElementsKind : uint8_t;
20 : class FixedTypedArrayBase;
21 : template <typename T>
22 : class Handle;
23 : class Heap;
24 : class Isolate;
25 : class Map;
26 : class PropertyCell;
27 : class String;
28 : class Symbol;
29 : class RootVisitor;
30 :
31 : // Defines all the read-only roots in Heap.
32 : #define STRONG_READ_ONLY_ROOT_LIST(V) \
33 : /* Cluster the most popular ones in a few cache lines here at the top. */ \
34 : /* The first 32 entries are most often used in the startup snapshot and */ \
35 : /* can use a shorter representation in the serialization format. */ \
36 : V(Map, free_space_map, FreeSpaceMap) \
37 : V(Map, one_pointer_filler_map, OnePointerFillerMap) \
38 : V(Map, two_pointer_filler_map, TwoPointerFillerMap) \
39 : V(Oddball, uninitialized_value, UninitializedValue) \
40 : V(Oddball, undefined_value, UndefinedValue) \
41 : V(Oddball, the_hole_value, TheHoleValue) \
42 : V(Oddball, null_value, NullValue) \
43 : V(Oddball, true_value, TrueValue) \
44 : V(Oddball, false_value, FalseValue) \
45 : V(String, empty_string, empty_string) \
46 : V(Map, meta_map, MetaMap) \
47 : V(Map, byte_array_map, ByteArrayMap) \
48 : V(Map, fixed_array_map, FixedArrayMap) \
49 : V(Map, fixed_cow_array_map, FixedCOWArrayMap) \
50 : V(Map, hash_table_map, HashTableMap) \
51 : V(Map, symbol_map, SymbolMap) \
52 : V(Map, one_byte_string_map, OneByteStringMap) \
53 : V(Map, one_byte_internalized_string_map, OneByteInternalizedStringMap) \
54 : V(Map, scope_info_map, ScopeInfoMap) \
55 : V(Map, shared_function_info_map, SharedFunctionInfoMap) \
56 : V(Map, code_map, CodeMap) \
57 : V(Map, function_context_map, FunctionContextMap) \
58 : V(Map, cell_map, CellMap) \
59 : V(Map, global_property_cell_map, GlobalPropertyCellMap) \
60 : V(Map, foreign_map, ForeignMap) \
61 : V(Map, heap_number_map, HeapNumberMap) \
62 : V(Map, transition_array_map, TransitionArrayMap) \
63 : /* TODO(mythria): Once lazy feedback lands, check if feedback vector map */ \
64 : /* is still a popular map */ \
65 : V(Map, feedback_vector_map, FeedbackVectorMap) \
66 : V(ScopeInfo, empty_scope_info, EmptyScopeInfo) \
67 : V(FixedArray, empty_fixed_array, EmptyFixedArray) \
68 : V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray) \
69 : /* Entries beyond the first 32 */ \
70 : /* Oddballs */ \
71 : V(Oddball, arguments_marker, ArgumentsMarker) \
72 : V(Oddball, exception, Exception) \
73 : V(Oddball, termination_exception, TerminationException) \
74 : V(Oddball, optimized_out, OptimizedOut) \
75 : V(Oddball, stale_register, StaleRegister) \
76 : /* Context maps */ \
77 : V(Map, native_context_map, NativeContextMap) \
78 : V(Map, module_context_map, ModuleContextMap) \
79 : V(Map, eval_context_map, EvalContextMap) \
80 : V(Map, script_context_map, ScriptContextMap) \
81 : V(Map, await_context_map, AwaitContextMap) \
82 : V(Map, block_context_map, BlockContextMap) \
83 : V(Map, catch_context_map, CatchContextMap) \
84 : V(Map, with_context_map, WithContextMap) \
85 : V(Map, debug_evaluate_context_map, DebugEvaluateContextMap) \
86 : V(Map, script_context_table_map, ScriptContextTableMap) \
87 : /* Maps */ \
88 : V(Map, closure_feedback_cell_array_map, ClosureFeedbackCellArrayMap) \
89 : V(Map, feedback_metadata_map, FeedbackMetadataArrayMap) \
90 : V(Map, array_list_map, ArrayListMap) \
91 : V(Map, bigint_map, BigIntMap) \
92 : V(Map, object_boilerplate_description_map, ObjectBoilerplateDescriptionMap) \
93 : V(Map, bytecode_array_map, BytecodeArrayMap) \
94 : V(Map, code_data_container_map, CodeDataContainerMap) \
95 : V(Map, descriptor_array_map, DescriptorArrayMap) \
96 : V(Map, fixed_double_array_map, FixedDoubleArrayMap) \
97 : V(Map, global_dictionary_map, GlobalDictionaryMap) \
98 : V(Map, many_closures_cell_map, ManyClosuresCellMap) \
99 : V(Map, module_info_map, ModuleInfoMap) \
100 : V(Map, mutable_heap_number_map, MutableHeapNumberMap) \
101 : V(Map, name_dictionary_map, NameDictionaryMap) \
102 : V(Map, no_closures_cell_map, NoClosuresCellMap) \
103 : V(Map, number_dictionary_map, NumberDictionaryMap) \
104 : V(Map, one_closure_cell_map, OneClosureCellMap) \
105 : V(Map, ordered_hash_map_map, OrderedHashMapMap) \
106 : V(Map, ordered_hash_set_map, OrderedHashSetMap) \
107 : V(Map, ordered_name_dictionary_map, OrderedNameDictionaryMap) \
108 : V(Map, preparse_data_map, PreparseDataMap) \
109 : V(Map, property_array_map, PropertyArrayMap) \
110 : V(Map, side_effect_call_handler_info_map, SideEffectCallHandlerInfoMap) \
111 : V(Map, side_effect_free_call_handler_info_map, \
112 : SideEffectFreeCallHandlerInfoMap) \
113 : V(Map, next_call_side_effect_free_call_handler_info_map, \
114 : NextCallSideEffectFreeCallHandlerInfoMap) \
115 : V(Map, simple_number_dictionary_map, SimpleNumberDictionaryMap) \
116 : V(Map, sloppy_arguments_elements_map, SloppyArgumentsElementsMap) \
117 : V(Map, small_ordered_hash_map_map, SmallOrderedHashMapMap) \
118 : V(Map, small_ordered_hash_set_map, SmallOrderedHashSetMap) \
119 : V(Map, small_ordered_name_dictionary_map, SmallOrderedNameDictionaryMap) \
120 : V(Map, string_table_map, StringTableMap) \
121 : V(Map, uncompiled_data_without_preparse_data_map, \
122 : UncompiledDataWithoutPreparseDataMap) \
123 : V(Map, uncompiled_data_with_preparse_data_map, \
124 : UncompiledDataWithPreparseDataMap) \
125 : V(Map, weak_fixed_array_map, WeakFixedArrayMap) \
126 : V(Map, weak_array_list_map, WeakArrayListMap) \
127 : V(Map, ephemeron_hash_table_map, EphemeronHashTableMap) \
128 : V(Map, embedder_data_array_map, EmbedderDataArrayMap) \
129 : V(Map, weak_cell_map, WeakCellMap) \
130 : /* String maps */ \
131 : V(Map, native_source_string_map, NativeSourceStringMap) \
132 : V(Map, string_map, StringMap) \
133 : V(Map, cons_one_byte_string_map, ConsOneByteStringMap) \
134 : V(Map, cons_string_map, ConsStringMap) \
135 : V(Map, thin_one_byte_string_map, ThinOneByteStringMap) \
136 : V(Map, thin_string_map, ThinStringMap) \
137 : V(Map, sliced_string_map, SlicedStringMap) \
138 : V(Map, sliced_one_byte_string_map, SlicedOneByteStringMap) \
139 : V(Map, external_string_map, ExternalStringMap) \
140 : V(Map, external_one_byte_string_map, ExternalOneByteStringMap) \
141 : V(Map, uncached_external_string_map, UncachedExternalStringMap) \
142 : V(Map, internalized_string_map, InternalizedStringMap) \
143 : V(Map, external_internalized_string_map, ExternalInternalizedStringMap) \
144 : V(Map, external_one_byte_internalized_string_map, \
145 : ExternalOneByteInternalizedStringMap) \
146 : V(Map, uncached_external_internalized_string_map, \
147 : UncachedExternalInternalizedStringMap) \
148 : V(Map, uncached_external_one_byte_internalized_string_map, \
149 : UncachedExternalOneByteInternalizedStringMap) \
150 : V(Map, uncached_external_one_byte_string_map, \
151 : UncachedExternalOneByteStringMap) \
152 : /* Array element maps */ \
153 : V(Map, fixed_uint8_array_map, FixedUint8ArrayMap) \
154 : V(Map, fixed_int8_array_map, FixedInt8ArrayMap) \
155 : V(Map, fixed_uint16_array_map, FixedUint16ArrayMap) \
156 : V(Map, fixed_int16_array_map, FixedInt16ArrayMap) \
157 : V(Map, fixed_uint32_array_map, FixedUint32ArrayMap) \
158 : V(Map, fixed_int32_array_map, FixedInt32ArrayMap) \
159 : V(Map, fixed_float32_array_map, FixedFloat32ArrayMap) \
160 : V(Map, fixed_float64_array_map, FixedFloat64ArrayMap) \
161 : V(Map, fixed_uint8_clamped_array_map, FixedUint8ClampedArrayMap) \
162 : V(Map, fixed_biguint64_array_map, FixedBigUint64ArrayMap) \
163 : V(Map, fixed_bigint64_array_map, FixedBigInt64ArrayMap) \
164 : /* Oddball maps */ \
165 : V(Map, undefined_map, UndefinedMap) \
166 : V(Map, the_hole_map, TheHoleMap) \
167 : V(Map, null_map, NullMap) \
168 : V(Map, boolean_map, BooleanMap) \
169 : V(Map, uninitialized_map, UninitializedMap) \
170 : V(Map, arguments_marker_map, ArgumentsMarkerMap) \
171 : V(Map, exception_map, ExceptionMap) \
172 : V(Map, termination_exception_map, TerminationExceptionMap) \
173 : V(Map, optimized_out_map, OptimizedOutMap) \
174 : V(Map, stale_register_map, StaleRegisterMap) \
175 : V(Map, self_reference_marker_map, SelfReferenceMarkerMap) \
176 : /* Canonical empty values */ \
177 : V(EnumCache, empty_enum_cache, EmptyEnumCache) \
178 : V(PropertyArray, empty_property_array, EmptyPropertyArray) \
179 : V(ByteArray, empty_byte_array, EmptyByteArray) \
180 : V(ObjectBoilerplateDescription, empty_object_boilerplate_description, \
181 : EmptyObjectBoilerplateDescription) \
182 : V(ArrayBoilerplateDescription, empty_array_boilerplate_description, \
183 : EmptyArrayBoilerplateDescription) \
184 : V(ClosureFeedbackCellArray, empty_closure_feedback_cell_array, \
185 : EmptyClosureFeedbackCellArray) \
186 : V(FixedTypedArrayBase, empty_fixed_uint8_array, EmptyFixedUint8Array) \
187 : V(FixedTypedArrayBase, empty_fixed_int8_array, EmptyFixedInt8Array) \
188 : V(FixedTypedArrayBase, empty_fixed_uint16_array, EmptyFixedUint16Array) \
189 : V(FixedTypedArrayBase, empty_fixed_int16_array, EmptyFixedInt16Array) \
190 : V(FixedTypedArrayBase, empty_fixed_uint32_array, EmptyFixedUint32Array) \
191 : V(FixedTypedArrayBase, empty_fixed_int32_array, EmptyFixedInt32Array) \
192 : V(FixedTypedArrayBase, empty_fixed_float32_array, EmptyFixedFloat32Array) \
193 : V(FixedTypedArrayBase, empty_fixed_float64_array, EmptyFixedFloat64Array) \
194 : V(FixedTypedArrayBase, empty_fixed_uint8_clamped_array, \
195 : EmptyFixedUint8ClampedArray) \
196 : V(FixedTypedArrayBase, empty_fixed_biguint64_array, \
197 : EmptyFixedBigUint64Array) \
198 : V(FixedTypedArrayBase, empty_fixed_bigint64_array, EmptyFixedBigInt64Array) \
199 : V(FixedArray, empty_sloppy_arguments_elements, EmptySloppyArgumentsElements) \
200 : V(NumberDictionary, empty_slow_element_dictionary, \
201 : EmptySlowElementDictionary) \
202 : V(FixedArray, empty_ordered_hash_map, EmptyOrderedHashMap) \
203 : V(FixedArray, empty_ordered_hash_set, EmptyOrderedHashSet) \
204 : V(FeedbackMetadata, empty_feedback_metadata, EmptyFeedbackMetadata) \
205 : V(PropertyCell, empty_property_cell, EmptyPropertyCell) \
206 : V(NameDictionary, empty_property_dictionary, EmptyPropertyDictionary) \
207 : V(InterceptorInfo, noop_interceptor_info, NoOpInterceptorInfo) \
208 : V(WeakFixedArray, empty_weak_fixed_array, EmptyWeakFixedArray) \
209 : V(WeakArrayList, empty_weak_array_list, EmptyWeakArrayList) \
210 : /* Special numbers */ \
211 : V(HeapNumber, nan_value, NanValue) \
212 : V(HeapNumber, hole_nan_value, HoleNanValue) \
213 : V(HeapNumber, infinity_value, InfinityValue) \
214 : V(HeapNumber, minus_zero_value, MinusZeroValue) \
215 : V(HeapNumber, minus_infinity_value, MinusInfinityValue) \
216 : /* Marker for self-references during code-generation */ \
217 : V(HeapObject, self_reference_marker, SelfReferenceMarker) \
218 : /* Canonical trampoline RelocInfo */ \
219 : V(ByteArray, off_heap_trampoline_relocation_info, \
220 : OffHeapTrampolineRelocationInfo) \
221 : /* Hash seed */ \
222 : V(ByteArray, hash_seed, HashSeed)
223 :
224 : // Mutable roots that are known to be immortal immovable, for which we can
225 : // safely skip write barriers.
226 : #define STRONG_MUTABLE_IMMOVABLE_ROOT_LIST(V) \
227 : ACCESSOR_INFO_ROOT_LIST(V) \
228 : /* Maps */ \
229 : V(Map, external_map, ExternalMap) \
230 : V(Map, message_object_map, JSMessageObjectMap) \
231 : /* Canonical empty values */ \
232 : V(Script, empty_script, EmptyScript) \
233 : V(FeedbackCell, many_closures_cell, ManyClosuresCell) \
234 : V(Cell, invalid_prototype_validity_cell, InvalidPrototypeValidityCell) \
235 : /* Protectors */ \
236 : V(Cell, array_constructor_protector, ArrayConstructorProtector) \
237 : V(PropertyCell, no_elements_protector, NoElementsProtector) \
238 : V(Cell, is_concat_spreadable_protector, IsConcatSpreadableProtector) \
239 : V(PropertyCell, array_species_protector, ArraySpeciesProtector) \
240 : V(PropertyCell, typed_array_species_protector, TypedArraySpeciesProtector) \
241 : V(PropertyCell, regexp_species_protector, RegExpSpeciesProtector) \
242 : V(PropertyCell, promise_species_protector, PromiseSpeciesProtector) \
243 : V(Cell, string_length_protector, StringLengthProtector) \
244 : V(PropertyCell, array_iterator_protector, ArrayIteratorProtector) \
245 : V(PropertyCell, array_buffer_detaching_protector, \
246 : ArrayBufferDetachingProtector) \
247 : V(PropertyCell, promise_hook_protector, PromiseHookProtector) \
248 : V(Cell, promise_resolve_protector, PromiseResolveProtector) \
249 : V(PropertyCell, map_iterator_protector, MapIteratorProtector) \
250 : V(PropertyCell, promise_then_protector, PromiseThenProtector) \
251 : V(PropertyCell, set_iterator_protector, SetIteratorProtector) \
252 : V(PropertyCell, string_iterator_protector, StringIteratorProtector) \
253 : /* Caches */ \
254 : V(FixedArray, single_character_string_cache, SingleCharacterStringCache) \
255 : V(FixedArray, string_split_cache, StringSplitCache) \
256 : V(FixedArray, regexp_multiple_cache, RegExpMultipleCache) \
257 : /* Indirection lists for isolate-independent builtins */ \
258 : V(FixedArray, builtins_constants_table, BuiltinsConstantsTable)
259 :
260 : // These root references can be updated by the mutator.
261 : #define STRONG_MUTABLE_MOVABLE_ROOT_LIST(V) \
262 : /* Caches */ \
263 : V(FixedArray, number_string_cache, NumberStringCache) \
264 : /* Lists and dictionaries */ \
265 : V(NameDictionary, public_symbol_table, PublicSymbolTable) \
266 : V(NameDictionary, api_symbol_table, ApiSymbolTable) \
267 : V(NameDictionary, api_private_symbol_table, ApiPrivateSymbolTable) \
268 : V(WeakArrayList, script_list, ScriptList) \
269 : V(FixedArray, materialized_objects, MaterializedObjects) \
270 : V(WeakArrayList, detached_contexts, DetachedContexts) \
271 : V(WeakArrayList, retaining_path_targets, RetainingPathTargets) \
272 : V(WeakArrayList, retained_maps, RetainedMaps) \
273 : /* Feedback vectors that we need for code coverage or type profile */ \
274 : V(Object, feedback_vectors_for_profiling_tools, \
275 : FeedbackVectorsForProfilingTools) \
276 : V(WeakArrayList, noscript_shared_function_infos, \
277 : NoScriptSharedFunctionInfos) \
278 : V(FixedArray, serialized_objects, SerializedObjects) \
279 : V(FixedArray, serialized_global_proxy_sizes, SerializedGlobalProxySizes) \
280 : V(TemplateList, message_listeners, MessageListeners) \
281 : /* Support for async stack traces */ \
282 : V(HeapObject, current_microtask, CurrentMicrotask) \
283 : /* JSFinalizationGroup objects which need cleanup */ \
284 : V(Object, dirty_js_finalization_groups, DirtyJSFinalizationGroups) \
285 : /* KeepDuringJob set for JS WeakRefs */ \
286 : V(HeapObject, weak_refs_keep_during_job, WeakRefsKeepDuringJob) \
287 : V(HeapObject, interpreter_entry_trampoline_for_profiling, \
288 : InterpreterEntryTrampolineForProfiling) \
289 : V(Object, pending_optimize_for_test_bytecode, PendingOptimizeForTestBytecode)
290 :
291 : // Entries in this list are limited to Smis and are not visited during GC.
292 : #define SMI_ROOT_LIST(V) \
293 : V(Smi, stack_limit, StackLimit) \
294 : V(Smi, real_stack_limit, RealStackLimit) \
295 : V(Smi, last_script_id, LastScriptId) \
296 : V(Smi, last_debugging_id, LastDebuggingId) \
297 : /* To distinguish the function templates, so that we can find them in the */ \
298 : /* function cache of the native context. */ \
299 : V(Smi, next_template_serial_number, NextTemplateSerialNumber) \
300 : V(Smi, arguments_adaptor_deopt_pc_offset, ArgumentsAdaptorDeoptPCOffset) \
301 : V(Smi, construct_stub_create_deopt_pc_offset, \
302 : ConstructStubCreateDeoptPCOffset) \
303 : V(Smi, construct_stub_invoke_deopt_pc_offset, \
304 : ConstructStubInvokeDeoptPCOffset) \
305 : V(Smi, interpreter_entry_return_pc_offset, InterpreterEntryReturnPCOffset)
306 :
307 : // Adapts one INTERNALIZED_STRING_LIST_GENERATOR entry to
308 : // the ROOT_LIST-compatible entry
309 : #define INTERNALIZED_STRING_LIST_ADAPTER(V, name, ...) V(String, name, name)
310 :
311 : // Produces (String, name, CamelCase) entries
312 : #define INTERNALIZED_STRING_ROOT_LIST(V) \
313 : INTERNALIZED_STRING_LIST_GENERATOR(INTERNALIZED_STRING_LIST_ADAPTER, V)
314 :
315 : // Adapts one XXX_SYMBOL_LIST_GENERATOR entry to the ROOT_LIST-compatible entry
316 : #define SYMBOL_ROOT_LIST_ADAPTER(V, name, ...) V(Symbol, name, name)
317 :
318 : // Produces (Symbol, name, CamelCase) entries
319 : #define PRIVATE_SYMBOL_ROOT_LIST(V) \
320 : PRIVATE_SYMBOL_LIST_GENERATOR(SYMBOL_ROOT_LIST_ADAPTER, V)
321 : #define PUBLIC_SYMBOL_ROOT_LIST(V) \
322 : PUBLIC_SYMBOL_LIST_GENERATOR(SYMBOL_ROOT_LIST_ADAPTER, V)
323 : #define WELL_KNOWN_SYMBOL_ROOT_LIST(V) \
324 : WELL_KNOWN_SYMBOL_LIST_GENERATOR(SYMBOL_ROOT_LIST_ADAPTER, V)
325 :
326 : // Adapts one ACCESSOR_INFO_LIST_GENERATOR entry to the ROOT_LIST-compatible
327 : // entry
328 : #define ACCESSOR_INFO_ROOT_LIST_ADAPTER(V, name, CamelName, ...) \
329 : V(AccessorInfo, name##_accessor, CamelName##Accessor)
330 :
331 : // Produces (AccessorInfo, name, CamelCase) entries
332 : #define ACCESSOR_INFO_ROOT_LIST(V) \
333 : ACCESSOR_INFO_LIST_GENERATOR(ACCESSOR_INFO_ROOT_LIST_ADAPTER, V)
334 :
335 : #define READ_ONLY_ROOT_LIST(V) \
336 : STRONG_READ_ONLY_ROOT_LIST(V) \
337 : INTERNALIZED_STRING_ROOT_LIST(V) \
338 : PRIVATE_SYMBOL_ROOT_LIST(V) \
339 : PUBLIC_SYMBOL_ROOT_LIST(V) \
340 : WELL_KNOWN_SYMBOL_ROOT_LIST(V) \
341 : STRUCT_MAPS_LIST(V) \
342 : ALLOCATION_SITE_MAPS_LIST(V) \
343 : DATA_HANDLER_MAPS_LIST(V)
344 :
345 : #define MUTABLE_ROOT_LIST(V) \
346 : STRONG_MUTABLE_IMMOVABLE_ROOT_LIST(V) \
347 : STRONG_MUTABLE_MOVABLE_ROOT_LIST(V) \
348 : V(StringTable, string_table, StringTable) \
349 : SMI_ROOT_LIST(V)
350 :
351 : #define ROOT_LIST(V) \
352 : READ_ONLY_ROOT_LIST(V) \
353 : MUTABLE_ROOT_LIST(V)
354 :
355 : // Declare all the root indices. This defines the root list order.
356 : // clang-format off
357 : enum class RootIndex : uint16_t {
358 : #define DECL(type, name, CamelName) k##CamelName,
359 : ROOT_LIST(DECL)
360 : #undef DECL
361 :
362 : kRootListLength,
363 :
364 : // Helper aliases for inclusive regions of root indices.
365 : kFirstRoot = 0,
366 : kLastRoot = kRootListLength - 1,
367 :
368 : #define ROOT(...) +1
369 : kReadOnlyRootsCount = 0 READ_ONLY_ROOT_LIST(ROOT),
370 : kImmortalImmovableRootsCount =
371 : kReadOnlyRootsCount STRONG_MUTABLE_IMMOVABLE_ROOT_LIST(ROOT),
372 : #undef ROOT
373 : kFirstReadOnlyRoot = kFirstRoot,
374 : kLastReadOnlyRoot = kFirstReadOnlyRoot + kReadOnlyRootsCount - 1,
375 :
376 : // The strong roots visited by the garbage collector (not including read-only
377 : // roots).
378 : kFirstStrongRoot = kLastReadOnlyRoot + 1,
379 : // (kStringTable is not a strong root).
380 : kLastStrongRoot = kStringTable - 1,
381 :
382 : // All of the strong roots plus the read-only roots.
383 : kFirstStrongOrReadOnlyRoot = kFirstRoot,
384 : kLastStrongOrReadOnlyRoot = kLastStrongRoot,
385 :
386 : // All immortal immovable roots including read only ones.
387 : kFirstImmortalImmovableRoot = kFirstReadOnlyRoot,
388 : kLastImmortalImmovableRoot =
389 : kFirstImmortalImmovableRoot + kImmortalImmovableRootsCount - 1,
390 :
391 : kFirstSmiRoot = kStringTable + 1,
392 : kLastSmiRoot = kLastRoot
393 : };
394 : // clang-format on
395 :
396 : // Represents a storage of V8 heap roots.
397 : class RootsTable {
398 : public:
399 : static constexpr size_t kEntriesCount =
400 : static_cast<size_t>(RootIndex::kRootListLength);
401 :
402 62442 : RootsTable() : roots_{} {}
403 :
404 : inline bool IsRootHandleLocation(Address* handle_location,
405 : RootIndex* index) const;
406 :
407 : template <typename T>
408 : bool IsRootHandle(Handle<T> handle, RootIndex* index) const;
409 :
410 : Address const& operator[](RootIndex root_index) const {
411 : size_t index = static_cast<size_t>(root_index);
412 : DCHECK_LT(index, kEntriesCount);
413 : return roots_[index];
414 : }
415 :
416 : static const char* name(RootIndex root_index) {
417 234820 : size_t index = static_cast<size_t>(root_index);
418 : DCHECK_LT(index, kEntriesCount);
419 234820 : return root_names_[index];
420 : }
421 :
422 : static constexpr int offset_of(RootIndex root_index) {
423 3523023 : return static_cast<int>(root_index) * kSystemPointerSize;
424 : }
425 :
426 : static RootIndex RootIndexForFixedTypedArray(ExternalArrayType array_type);
427 : static RootIndex RootIndexForFixedTypedArray(ElementsKind elements_kind);
428 : static RootIndex RootIndexForEmptyFixedTypedArray(ElementsKind elements_kind);
429 :
430 : // Immortal immovable root objects are allocated in OLD space and GC never
431 : // moves them and the root table entries are guaranteed to not be modified
432 : // after initialization. Note, however, that contents of those root objects
433 : // that are allocated in writable space can still be modified after
434 : // initialization.
435 : // Generated code can treat direct references to these roots as constants.
436 : static constexpr bool IsImmortalImmovable(RootIndex root_index) {
437 : STATIC_ASSERT(static_cast<int>(RootIndex::kFirstImmortalImmovableRoot) ==
438 : 0);
439 : return static_cast<unsigned>(root_index) <=
440 : static_cast<unsigned>(RootIndex::kLastImmortalImmovableRoot);
441 : }
442 :
443 : private:
444 : FullObjectSlot begin() {
445 402201 : return FullObjectSlot(&roots_[static_cast<size_t>(RootIndex::kFirstRoot)]);
446 : }
447 : FullObjectSlot end() {
448 : return FullObjectSlot(
449 : &roots_[static_cast<size_t>(RootIndex::kLastRoot) + 1]);
450 : }
451 :
452 : // Used for iterating over all of the read-only and mutable strong roots.
453 : FullObjectSlot strong_or_read_only_roots_begin() {
454 : STATIC_ASSERT(static_cast<size_t>(RootIndex::kLastReadOnlyRoot) ==
455 : static_cast<size_t>(RootIndex::kFirstStrongRoot) - 1);
456 : return FullObjectSlot(
457 : &roots_[static_cast<size_t>(RootIndex::kFirstStrongOrReadOnlyRoot)]);
458 : }
459 : FullObjectSlot strong_or_read_only_roots_end() {
460 : return FullObjectSlot(
461 : &roots_[static_cast<size_t>(RootIndex::kLastStrongOrReadOnlyRoot) + 1]);
462 : }
463 :
464 : // The read-only, strong and Smi roots as defined by these accessors are all
465 : // disjoint.
466 : FullObjectSlot read_only_roots_begin() {
467 : return FullObjectSlot(
468 63045 : &roots_[static_cast<size_t>(RootIndex::kFirstReadOnlyRoot)]);
469 : }
470 : FullObjectSlot read_only_roots_end() {
471 : return FullObjectSlot(
472 63045 : &roots_[static_cast<size_t>(RootIndex::kLastReadOnlyRoot) + 1]);
473 : }
474 :
475 : FullObjectSlot strong_roots_begin() {
476 : return FullObjectSlot(
477 275539 : &roots_[static_cast<size_t>(RootIndex::kFirstStrongRoot)]);
478 : }
479 : FullObjectSlot strong_roots_end() {
480 : return FullObjectSlot(
481 275539 : &roots_[static_cast<size_t>(RootIndex::kLastStrongRoot) + 1]);
482 : }
483 :
484 : FullObjectSlot smi_roots_begin() {
485 : return FullObjectSlot(
486 62647 : &roots_[static_cast<size_t>(RootIndex::kFirstSmiRoot)]);
487 : }
488 : FullObjectSlot smi_roots_end() {
489 : return FullObjectSlot(
490 62647 : &roots_[static_cast<size_t>(RootIndex::kLastSmiRoot) + 1]);
491 : }
492 :
493 : Address& operator[](RootIndex root_index) {
494 953722037 : size_t index = static_cast<size_t>(root_index);
495 : DCHECK_LT(index, kEntriesCount);
496 1293003715 : return roots_[index];
497 : }
498 :
499 : Address roots_[kEntriesCount];
500 : static const char* root_names_[kEntriesCount];
501 :
502 : friend class Isolate;
503 : friend class Heap;
504 : friend class Factory;
505 : friend class ReadOnlyHeap;
506 : friend class ReadOnlyRoots;
507 : friend class RootsSerializer;
508 : };
509 :
510 : class ReadOnlyRoots {
511 : public:
512 : V8_INLINE explicit ReadOnlyRoots(Heap* heap);
513 : V8_INLINE explicit ReadOnlyRoots(Isolate* isolate);
514 :
515 : #define ROOT_ACCESSOR(Type, name, CamelName) \
516 : V8_INLINE class Type name() const; \
517 : V8_INLINE Handle<Type> name##_handle() const;
518 :
519 : READ_ONLY_ROOT_LIST(ROOT_ACCESSOR)
520 : #undef ROOT_ACCESSOR
521 :
522 : V8_INLINE Map MapForFixedTypedArray(ExternalArrayType array_type);
523 : V8_INLINE Map MapForFixedTypedArray(ElementsKind elements_kind);
524 : V8_INLINE FixedTypedArrayBase
525 : EmptyFixedTypedArrayForTypedArray(ElementsKind elements_kind);
526 :
527 : // Iterate over all the read-only roots. This is not necessary for garbage
528 : // collection and is usually only performed as part of (de)serialization or
529 : // heap verification.
530 : void Iterate(RootVisitor* visitor);
531 :
532 : #ifdef DEBUG
533 : V8_EXPORT_PRIVATE bool CheckType(RootIndex index) const;
534 : #endif
535 :
536 : private:
537 : RootsTable& roots_table_;
538 : };
539 :
540 : } // namespace internal
541 : } // namespace v8
542 :
543 : #endif // V8_ROOTS_H_
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