Line data Source code
1 : // Copyright 2012 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_PROPERTY_DETAILS_H_
6 : #define V8_PROPERTY_DETAILS_H_
7 :
8 : #include "include/v8.h"
9 : #include "src/allocation.h"
10 : // TODO(ishell): remove once FLAG_track_constant_fields is removed.
11 : #include "src/flags.h"
12 : #include "src/utils.h"
13 :
14 : namespace v8 {
15 : namespace internal {
16 :
17 : // ES6 6.1.7.1
18 : enum PropertyAttributes {
19 : NONE = ::v8::None,
20 : READ_ONLY = ::v8::ReadOnly,
21 : DONT_ENUM = ::v8::DontEnum,
22 : DONT_DELETE = ::v8::DontDelete,
23 :
24 : ALL_ATTRIBUTES_MASK = READ_ONLY | DONT_ENUM | DONT_DELETE,
25 :
26 : SEALED = DONT_DELETE,
27 : FROZEN = SEALED | READ_ONLY,
28 :
29 : ABSENT = 64, // Used in runtime to indicate a property is absent.
30 : // ABSENT can never be stored in or returned from a descriptor's attributes
31 : // bitfield. It is only used as a return value meaning the attributes of
32 : // a non-existent property.
33 : };
34 :
35 :
36 : enum PropertyFilter {
37 : ALL_PROPERTIES = 0,
38 : ONLY_WRITABLE = 1,
39 : ONLY_ENUMERABLE = 2,
40 : ONLY_CONFIGURABLE = 4,
41 : SKIP_STRINGS = 8,
42 : SKIP_SYMBOLS = 16,
43 : ONLY_ALL_CAN_READ = 32,
44 : ENUMERABLE_STRINGS = ONLY_ENUMERABLE | SKIP_SYMBOLS,
45 : };
46 : // Enable fast comparisons of PropertyAttributes against PropertyFilters.
47 : STATIC_ASSERT(ALL_PROPERTIES == static_cast<PropertyFilter>(NONE));
48 : STATIC_ASSERT(ONLY_WRITABLE == static_cast<PropertyFilter>(READ_ONLY));
49 : STATIC_ASSERT(ONLY_ENUMERABLE == static_cast<PropertyFilter>(DONT_ENUM));
50 : STATIC_ASSERT(ONLY_CONFIGURABLE == static_cast<PropertyFilter>(DONT_DELETE));
51 : STATIC_ASSERT(((SKIP_STRINGS | SKIP_SYMBOLS | ONLY_ALL_CAN_READ) &
52 : ALL_ATTRIBUTES_MASK) == 0);
53 : STATIC_ASSERT(ALL_PROPERTIES ==
54 : static_cast<PropertyFilter>(v8::PropertyFilter::ALL_PROPERTIES));
55 : STATIC_ASSERT(ONLY_WRITABLE ==
56 : static_cast<PropertyFilter>(v8::PropertyFilter::ONLY_WRITABLE));
57 : STATIC_ASSERT(ONLY_ENUMERABLE ==
58 : static_cast<PropertyFilter>(v8::PropertyFilter::ONLY_ENUMERABLE));
59 : STATIC_ASSERT(ONLY_CONFIGURABLE == static_cast<PropertyFilter>(
60 : v8::PropertyFilter::ONLY_CONFIGURABLE));
61 : STATIC_ASSERT(SKIP_STRINGS ==
62 : static_cast<PropertyFilter>(v8::PropertyFilter::SKIP_STRINGS));
63 : STATIC_ASSERT(SKIP_SYMBOLS ==
64 : static_cast<PropertyFilter>(v8::PropertyFilter::SKIP_SYMBOLS));
65 :
66 : class Smi;
67 : class TypeInfo;
68 :
69 : // Order of kinds is significant.
70 : // Must fit in the BitField PropertyDetails::KindField.
71 : enum PropertyKind { kData = 0, kAccessor = 1 };
72 :
73 : // Order of modes is significant.
74 : // Must fit in the BitField PropertyDetails::LocationField.
75 : enum PropertyLocation { kField = 0, kDescriptor = 1 };
76 :
77 : // Order of modes is significant.
78 : // Must fit in the BitField PropertyDetails::ConstnessField.
79 : enum PropertyConstness { kMutable = 0, kConst = 1 };
80 :
81 : // TODO(ishell): remove once constant field tracking is done.
82 : const PropertyConstness kDefaultFieldConstness =
83 : FLAG_track_constant_fields ? kConst : kMutable;
84 :
85 : class Representation {
86 : public:
87 : enum Kind {
88 : kNone,
89 : kInteger8,
90 : kUInteger8,
91 : kInteger16,
92 : kUInteger16,
93 : kSmi,
94 : kInteger32,
95 : kDouble,
96 : kHeapObject,
97 : kTagged,
98 : kExternal,
99 : kNumRepresentations
100 : };
101 :
102 35455409 : Representation() : kind_(kNone) { }
103 :
104 : static Representation None() { return Representation(kNone); }
105 : static Representation Tagged() { return Representation(kTagged); }
106 : static Representation Integer8() { return Representation(kInteger8); }
107 : static Representation UInteger8() { return Representation(kUInteger8); }
108 : static Representation Integer16() { return Representation(kInteger16); }
109 : static Representation UInteger16() { return Representation(kUInteger16); }
110 : static Representation Smi() { return Representation(kSmi); }
111 : static Representation Integer32() { return Representation(kInteger32); }
112 14 : static Representation Double() { return Representation(kDouble); }
113 : static Representation HeapObject() { return Representation(kHeapObject); }
114 : static Representation External() { return Representation(kExternal); }
115 :
116 : static Representation FromKind(Kind kind) { return Representation(kind); }
117 :
118 : bool Equals(const Representation& other) const {
119 10320778 : return kind_ == other.kind_;
120 : }
121 :
122 : bool IsCompatibleForLoad(const Representation& other) const {
123 5846 : return (IsDouble() && other.IsDouble()) ||
124 5816 : (!IsDouble() && !other.IsDouble());
125 : }
126 :
127 : bool IsCompatibleForStore(const Representation& other) const {
128 : return Equals(other);
129 : }
130 :
131 20374867 : bool is_more_general_than(const Representation& other) const {
132 20374867 : if (kind_ == kExternal && other.kind_ == kNone) return true;
133 20367046 : if (kind_ == kExternal && other.kind_ == kExternal) return false;
134 20366926 : if (kind_ == kNone && other.kind_ == kExternal) return false;
135 :
136 : DCHECK(kind_ != kExternal);
137 : DCHECK(other.kind_ != kExternal);
138 22096758 : if (IsHeapObject()) return other.IsNone();
139 18621040 : if (kind_ == kUInteger8 && other.kind_ == kInteger8) return false;
140 18621020 : if (kind_ == kUInteger16 && other.kind_ == kInteger16) return false;
141 18621020 : return kind_ > other.kind_;
142 : }
143 :
144 : bool fits_into(const Representation& other) const {
145 22881211 : return other.is_more_general_than(*this) || other.Equals(*this);
146 : }
147 :
148 12934972 : Representation generalize(Representation other) {
149 12935118 : if (other.fits_into(*this)) return *this;
150 2521022 : if (other.is_more_general_than(*this)) return other;
151 : return Representation::Tagged();
152 : }
153 :
154 0 : int size() const {
155 : DCHECK(!IsNone());
156 0 : if (IsInteger8() || IsUInteger8()) {
157 : return sizeof(uint8_t);
158 : }
159 0 : if (IsInteger16() || IsUInteger16()) {
160 : return sizeof(uint16_t);
161 : }
162 0 : if (IsInteger32()) {
163 : return sizeof(uint32_t);
164 : }
165 0 : return kPointerSize;
166 : }
167 :
168 23746255 : Kind kind() const { return static_cast<Kind>(kind_); }
169 5294399 : bool IsNone() const { return kind_ == kNone; }
170 1026905 : bool IsInteger8() const { return kind_ == kInteger8; }
171 : bool IsUInteger8() const { return kind_ == kUInteger8; }
172 : bool IsInteger16() const { return kind_ == kInteger16; }
173 : bool IsUInteger16() const { return kind_ == kUInteger16; }
174 3799894 : bool IsTagged() const { return kind_ == kTagged; }
175 37104629 : bool IsSmi() const { return kind_ == kSmi; }
176 36353986 : bool IsSmiOrTagged() const { return IsSmi() || IsTagged(); }
177 153021 : bool IsInteger32() const { return kind_ == kInteger32; }
178 12336263 : bool IsSmiOrInteger32() const { return IsSmi() || IsInteger32(); }
179 433036424 : bool IsDouble() const { return kind_ == kDouble; }
180 0 : bool IsHeapObject() const { return kind_ == kHeapObject; }
181 1042809 : bool IsExternal() const { return kind_ == kExternal; }
182 1026905 : bool IsSpecialization() const {
183 1026905 : return IsInteger8() || IsUInteger8() ||
184 1026905 : IsInteger16() || IsUInteger16() ||
185 2051396 : IsSmi() || IsInteger32() || IsDouble();
186 : }
187 : const char* Mnemonic() const;
188 :
189 : private:
190 779509164 : explicit Representation(Kind k) : kind_(k) { }
191 :
192 : // Make sure kind fits in int8.
193 : STATIC_ASSERT(kNumRepresentations <= (1 << kBitsPerByte));
194 :
195 : int8_t kind_;
196 : };
197 :
198 :
199 : static const int kDescriptorIndexBitCount = 10;
200 : // The maximum number of descriptors we want in a descriptor array (should
201 : // fit in a page).
202 : static const int kMaxNumberOfDescriptors =
203 : (1 << kDescriptorIndexBitCount) - 2;
204 : static const int kInvalidEnumCacheSentinel =
205 : (1 << kDescriptorIndexBitCount) - 1;
206 :
207 : enum class PropertyCellType {
208 : // Meaningful when a property cell does not contain the hole.
209 : kUndefined, // The PREMONOMORPHIC of property cells.
210 : kConstant, // Cell has been assigned only once.
211 : kConstantType, // Cell has been assigned only one type.
212 : kMutable, // Cell will no longer be tracked as constant.
213 :
214 : // Meaningful when a property cell contains the hole.
215 : kUninitialized = kUndefined, // Cell has never been initialized.
216 : kInvalidated = kConstant, // Cell has been deleted, invalidated or never
217 : // existed.
218 :
219 : // For dictionaries not holding cells.
220 : kNoCell = kMutable,
221 : };
222 :
223 : enum class PropertyCellConstantType {
224 : kSmi,
225 : kStableMap,
226 : };
227 :
228 :
229 : // PropertyDetails captures type and attributes for a property.
230 : // They are used both in property dictionaries and instance descriptors.
231 : class PropertyDetails BASE_EMBEDDED {
232 : public:
233 : // Property details for dictionary mode properties/elements.
234 2880625 : PropertyDetails(PropertyKind kind, PropertyAttributes attributes, int index,
235 : PropertyCellType cell_type) {
236 9128063 : value_ = KindField::encode(kind) | LocationField::encode(kField) |
237 17546928 : AttributesField::encode(attributes) |
238 44245551 : DictionaryStorageField::encode(index) |
239 20126738 : PropertyCellTypeField::encode(cell_type);
240 2880625 : }
241 :
242 : // Property details for fast mode properties.
243 : PropertyDetails(PropertyKind kind, PropertyAttributes attributes,
244 : PropertyLocation location, PropertyConstness constness,
245 : Representation representation, int field_index = 0) {
246 1646126 : value_ = KindField::encode(kind) | AttributesField::encode(attributes) |
247 20023394 : LocationField::encode(location) |
248 22694971 : ConstnessField::encode(constness) |
249 41280002 : RepresentationField::encode(EncodeRepresentation(representation)) |
250 26282225 : FieldIndexField::encode(field_index);
251 : }
252 :
253 120 : static PropertyDetails Empty(
254 : PropertyCellType cell_type = PropertyCellType::kNoCell) {
255 120 : return PropertyDetails(kData, NONE, 0, cell_type);
256 : }
257 :
258 1110445765 : int pointer() const { return DescriptorPointer::decode(value_); }
259 :
260 : PropertyDetails set_pointer(int i) const {
261 204532584 : return PropertyDetails(value_, i);
262 : }
263 :
264 : PropertyDetails set_cell_type(PropertyCellType type) const {
265 8833395 : PropertyDetails details = *this;
266 : details.value_ = PropertyCellTypeField::update(details.value_, type);
267 : return details;
268 : }
269 :
270 : PropertyDetails set_index(int index) const {
271 : PropertyDetails details = *this;
272 28187644 : details.value_ = DictionaryStorageField::update(details.value_, index);
273 : return details;
274 : }
275 :
276 : PropertyDetails CopyWithRepresentation(Representation representation) const {
277 : return PropertyDetails(value_, representation);
278 : }
279 : PropertyDetails CopyWithConstness(PropertyConstness constness) const {
280 : return PropertyDetails(value_, constness);
281 : }
282 : PropertyDetails CopyAddAttributes(PropertyAttributes new_attributes) const {
283 : new_attributes =
284 104538 : static_cast<PropertyAttributes>(attributes() | new_attributes);
285 : return PropertyDetails(value_, new_attributes);
286 : }
287 :
288 : // Conversion for storing details as Object*.
289 : explicit inline PropertyDetails(Smi* smi);
290 : inline Smi* AsSmi() const;
291 :
292 : static uint8_t EncodeRepresentation(Representation representation) {
293 : return representation.kind();
294 : }
295 :
296 : static Representation DecodeRepresentation(uint32_t bits) {
297 : return Representation::FromKind(static_cast<Representation::Kind>(bits));
298 : }
299 :
300 236802541 : PropertyKind kind() const { return KindField::decode(value_); }
301 713315282 : PropertyLocation location() const { return LocationField::decode(value_); }
302 0 : PropertyConstness constness() const { return ConstnessField::decode(value_); }
303 :
304 0 : PropertyAttributes attributes() const {
305 24197407 : return AttributesField::decode(value_);
306 : }
307 :
308 : int dictionary_index() const {
309 264604053 : return DictionaryStorageField::decode(value_);
310 : }
311 :
312 62917623 : Representation representation() const {
313 332725208 : return DecodeRepresentation(RepresentationField::decode(value_));
314 : }
315 :
316 739121953 : int field_index() const { return FieldIndexField::decode(value_); }
317 :
318 : inline int field_width_in_words() const;
319 :
320 : static bool IsValidIndex(int index) {
321 30903219 : return DictionaryStorageField::is_valid(index);
322 : }
323 :
324 23271024 : bool IsReadOnly() const { return (attributes() & READ_ONLY) != 0; }
325 12946823 : bool IsConfigurable() const { return (attributes() & DONT_DELETE) == 0; }
326 23474762 : bool IsDontEnum() const { return (attributes() & DONT_ENUM) != 0; }
327 : bool IsEnumerable() const { return !IsDontEnum(); }
328 : PropertyCellType cell_type() const {
329 11918808 : return PropertyCellTypeField::decode(value_);
330 : }
331 :
332 : // Bit fields in value_ (type, shift, size). Must be public so the
333 : // constants can be embedded in generated code.
334 : class KindField : public BitField<PropertyKind, 0, 1> {};
335 : class LocationField : public BitField<PropertyLocation, KindField::kNext, 1> {
336 : };
337 : class ConstnessField
338 : : public BitField<PropertyConstness, LocationField::kNext, 1> {};
339 : class AttributesField
340 : : public BitField<PropertyAttributes, ConstnessField::kNext, 3> {};
341 : static const int kAttributesReadOnlyMask =
342 : (READ_ONLY << AttributesField::kShift);
343 : static const int kAttributesDontDeleteMask =
344 : (DONT_DELETE << AttributesField::kShift);
345 :
346 : // Bit fields for normalized objects.
347 : class PropertyCellTypeField
348 : : public BitField<PropertyCellType, AttributesField::kNext, 2> {};
349 : class DictionaryStorageField
350 : : public BitField<uint32_t, PropertyCellTypeField::kNext, 23> {};
351 :
352 : // Bit fields for fast objects.
353 : class RepresentationField
354 : : public BitField<uint32_t, AttributesField::kNext, 4> {};
355 : class DescriptorPointer
356 : : public BitField<uint32_t, RepresentationField::kNext,
357 : kDescriptorIndexBitCount> {}; // NOLINT
358 : class FieldIndexField : public BitField<uint32_t, DescriptorPointer::kNext,
359 : kDescriptorIndexBitCount> {
360 : }; // NOLINT
361 :
362 : // All bits for both fast and slow objects must fit in a smi.
363 : STATIC_ASSERT(DictionaryStorageField::kNext <= 31);
364 : STATIC_ASSERT(FieldIndexField::kNext <= 31);
365 :
366 : static const int kInitialIndex = 1;
367 :
368 : #ifdef OBJECT_PRINT
369 : // For our gdb macros, we should perhaps change these in the future.
370 : void Print(bool dictionary_mode);
371 : #endif
372 :
373 : enum PrintMode {
374 : kPrintAttributes = 1 << 0,
375 : kPrintFieldIndex = 1 << 1,
376 : kPrintRepresentation = 1 << 2,
377 : kPrintPointer = 1 << 3,
378 :
379 : kForProperties = kPrintFieldIndex,
380 : kForTransitions = kPrintAttributes,
381 : kPrintFull = -1,
382 : };
383 : void PrintAsSlowTo(std::ostream& out);
384 : void PrintAsFastTo(std::ostream& out, PrintMode mode = kPrintFull);
385 :
386 : private:
387 : PropertyDetails(int value, int pointer) {
388 202034643 : value_ = DescriptorPointer::update(value, pointer);
389 : }
390 : PropertyDetails(int value, Representation representation) {
391 : value_ = RepresentationField::update(
392 : value, EncodeRepresentation(representation));
393 : }
394 : PropertyDetails(int value, PropertyConstness constness) {
395 : value_ = ConstnessField::update(value, constness);
396 : }
397 : PropertyDetails(int value, PropertyAttributes attributes) {
398 : value_ = AttributesField::update(value, attributes);
399 : }
400 :
401 : uint32_t value_;
402 : };
403 :
404 : // kField location is more general than kDescriptor, kDescriptor generalizes
405 : // only to itself.
406 : inline bool IsGeneralizableTo(PropertyLocation a, PropertyLocation b) {
407 501000 : return b == kField || a == kDescriptor;
408 : }
409 :
410 : // kMutable constness is more general than kConst, kConst generalizes only to
411 : // itself.
412 : inline bool IsGeneralizableTo(PropertyConstness a, PropertyConstness b) {
413 25342103 : return b == kMutable || a == kConst;
414 : }
415 :
416 : inline PropertyConstness GeneralizeConstness(PropertyConstness a,
417 : PropertyConstness b) {
418 1552777 : return a == kMutable ? kMutable : b;
419 : }
420 :
421 : std::ostream& operator<<(std::ostream& os,
422 : const PropertyAttributes& attributes);
423 : } // namespace internal
424 : } // namespace v8
425 :
426 : #endif // V8_PROPERTY_DETAILS_H_
|
