| 1 | /* |
| 2 | * Copyright (C) 1999-2001 Harri Porten (porten@kde.org) |
| 3 | * Copyright (C) 2001 Peter Kelly (pmk@post.com) |
| 4 | * Copyright (C) 2003-2019 Apple Inc. All rights reserved. |
| 5 | * |
| 6 | * This library is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU Library General Public |
| 8 | * License as published by the Free Software Foundation; either |
| 9 | * version 2 of the License, or (at your option) any later version. |
| 10 | * |
| 11 | * This library is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | * Library General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Library General Public License |
| 17 | * along with this library; see the file COPYING.LIB. If not, write to |
| 18 | * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| 19 | * Boston, MA 02110-1301, USA. |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #pragma once |
| 24 | |
| 25 | #include "JSExportMacros.h" |
| 26 | #include "PureNaN.h" |
| 27 | #include <functional> |
| 28 | #include <math.h> |
| 29 | #include <stddef.h> |
| 30 | #include <stdint.h> |
| 31 | #include <wtf/Assertions.h> |
| 32 | #include <wtf/Forward.h> |
| 33 | #include <wtf/HashMap.h> |
| 34 | #include <wtf/HashTraits.h> |
| 35 | #include <wtf/MathExtras.h> |
| 36 | #include <wtf/MediaTime.h> |
| 37 | #include <wtf/StdLibExtras.h> |
| 38 | #include <wtf/TriState.h> |
| 39 | |
| 40 | namespace JSC { |
| 41 | |
| 42 | class AssemblyHelpers; |
| 43 | class JSBigInt; |
| 44 | class ExecState; |
| 45 | class JSCell; |
| 46 | class JSValueSource; |
| 47 | class VM; |
| 48 | class JSGlobalObject; |
| 49 | class JSObject; |
| 50 | class JSString; |
| 51 | class Identifier; |
| 52 | class PropertyName; |
| 53 | class PropertySlot; |
| 54 | class PutPropertySlot; |
| 55 | class Structure; |
| 56 | #if ENABLE(DFG_JIT) |
| 57 | namespace DFG { |
| 58 | class JITCompiler; |
| 59 | class OSRExitCompiler; |
| 60 | class SpeculativeJIT; |
| 61 | } |
| 62 | #endif |
| 63 | #if ENABLE(C_LOOP) |
| 64 | namespace LLInt { |
| 65 | class CLoop; |
| 66 | } |
| 67 | #endif |
| 68 | |
| 69 | struct ClassInfo; |
| 70 | struct DumpContext; |
| 71 | struct Instruction; |
| 72 | struct MethodTable; |
| 73 | enum class Unknown { }; |
| 74 | |
| 75 | template <class T, typename Traits> class WriteBarrierBase; |
| 76 | template<class T> |
| 77 | using WriteBarrierTraitsSelect = typename std::conditional<std::is_same<T, Unknown>::value, |
| 78 | DumbValueTraits<T>, DumbPtrTraits<T> |
| 79 | >::type; |
| 80 | |
| 81 | enum PreferredPrimitiveType { NoPreference, PreferNumber, PreferString }; |
| 82 | enum ECMAMode { StrictMode, NotStrictMode }; |
| 83 | |
| 84 | enum class CallType : unsigned; |
| 85 | struct CallData; |
| 86 | enum class ConstructType : unsigned; |
| 87 | struct ConstructData; |
| 88 | |
| 89 | typedef int64_t EncodedJSValue; |
| 90 | |
| 91 | union EncodedValueDescriptor { |
| 92 | int64_t asInt64; |
| 93 | #if USE(JSVALUE32_64) |
| 94 | double asDouble; |
| 95 | #elif USE(JSVALUE64) |
| 96 | JSCell* ptr; |
| 97 | #endif |
| 98 | |
| 99 | #if CPU(BIG_ENDIAN) |
| 100 | struct { |
| 101 | int32_t tag; |
| 102 | int32_t payload; |
| 103 | } asBits; |
| 104 | #else |
| 105 | struct { |
| 106 | int32_t payload; |
| 107 | int32_t tag; |
| 108 | } asBits; |
| 109 | #endif |
| 110 | }; |
| 111 | |
| 112 | #define TagOffset (offsetof(EncodedValueDescriptor, asBits.tag)) |
| 113 | #define PayloadOffset (offsetof(EncodedValueDescriptor, asBits.payload)) |
| 114 | |
| 115 | #if USE(JSVALUE64) |
| 116 | #define CellPayloadOffset 0 |
| 117 | #else |
| 118 | #define CellPayloadOffset PayloadOffset |
| 119 | #endif |
| 120 | |
| 121 | enum WhichValueWord { |
| 122 | TagWord, |
| 123 | PayloadWord |
| 124 | }; |
| 125 | |
| 126 | int64_t tryConvertToInt52(double); |
| 127 | bool isInt52(double); |
| 128 | |
| 129 | enum class SourceCodeRepresentation : uint8_t { |
| 130 | Other, |
| 131 | Integer, |
| 132 | Double |
| 133 | }; |
| 134 | |
| 135 | class JSValue { |
| 136 | friend struct EncodedJSValueHashTraits; |
| 137 | friend struct EncodedJSValueWithRepresentationHashTraits; |
| 138 | friend class AssemblyHelpers; |
| 139 | friend class JIT; |
| 140 | friend class JITSlowPathCall; |
| 141 | friend class JITStubs; |
| 142 | friend class JITStubCall; |
| 143 | friend class JSInterfaceJIT; |
| 144 | friend class JSValueSource; |
| 145 | friend class SpecializedThunkJIT; |
| 146 | #if ENABLE(DFG_JIT) |
| 147 | friend class DFG::JITCompiler; |
| 148 | friend class DFG::OSRExitCompiler; |
| 149 | friend class DFG::SpeculativeJIT; |
| 150 | #endif |
| 151 | #if ENABLE(C_LOOP) |
| 152 | friend class LLInt::CLoop; |
| 153 | #endif |
| 154 | |
| 155 | public: |
| 156 | #if USE(JSVALUE32_64) |
| 157 | enum { Int32Tag = 0xffffffff }; |
| 158 | enum { BooleanTag = 0xfffffffe }; |
| 159 | enum { NullTag = 0xfffffffd }; |
| 160 | enum { UndefinedTag = 0xfffffffc }; |
| 161 | enum { CellTag = 0xfffffffb }; |
| 162 | enum { EmptyValueTag = 0xfffffffa }; |
| 163 | enum { DeletedValueTag = 0xfffffff9 }; |
| 164 | |
| 165 | enum { LowestTag = DeletedValueTag }; |
| 166 | |
| 167 | #endif |
| 168 | |
| 169 | static EncodedJSValue encode(JSValue); |
| 170 | static JSValue decode(EncodedJSValue); |
| 171 | |
| 172 | enum JSNullTag { JSNull }; |
| 173 | enum JSUndefinedTag { JSUndefined }; |
| 174 | enum JSTrueTag { JSTrue }; |
| 175 | enum JSFalseTag { JSFalse }; |
| 176 | enum JSCellTag { JSCellType }; |
| 177 | enum EncodeAsDoubleTag { EncodeAsDouble }; |
| 178 | |
| 179 | JSValue(); |
| 180 | JSValue(JSNullTag); |
| 181 | JSValue(JSUndefinedTag); |
| 182 | JSValue(JSTrueTag); |
| 183 | JSValue(JSFalseTag); |
| 184 | JSValue(JSCell* ptr); |
| 185 | JSValue(const JSCell* ptr); |
| 186 | |
| 187 | // Numbers |
| 188 | JSValue(EncodeAsDoubleTag, double); |
| 189 | explicit JSValue(double); |
| 190 | explicit JSValue(char); |
| 191 | explicit JSValue(unsigned char); |
| 192 | explicit JSValue(short); |
| 193 | explicit JSValue(unsigned short); |
| 194 | explicit JSValue(int); |
| 195 | explicit JSValue(unsigned); |
| 196 | explicit JSValue(long); |
| 197 | explicit JSValue(unsigned long); |
| 198 | explicit JSValue(long long); |
| 199 | explicit JSValue(unsigned long long); |
| 200 | |
| 201 | explicit operator bool() const; |
| 202 | bool operator==(const JSValue& other) const; |
| 203 | bool operator!=(const JSValue& other) const; |
| 204 | |
| 205 | bool isInt32() const; |
| 206 | bool isUInt32() const; |
| 207 | bool isDouble() const; |
| 208 | bool isTrue() const; |
| 209 | bool isFalse() const; |
| 210 | |
| 211 | int32_t asInt32() const; |
| 212 | uint32_t asUInt32() const; |
| 213 | int64_t asAnyInt() const; |
| 214 | uint32_t asUInt32AsAnyInt() const; |
| 215 | int32_t asInt32AsAnyInt() const; |
| 216 | double asDouble() const; |
| 217 | bool asBoolean() const; |
| 218 | double asNumber() const; |
| 219 | |
| 220 | int32_t asInt32ForArithmetic() const; // Boolean becomes an int, but otherwise like asInt32(). |
| 221 | |
| 222 | // Querying the type. |
| 223 | bool isEmpty() const; |
| 224 | bool isFunction(VM&) const; |
| 225 | bool isCallable(VM&, CallType&, CallData&) const; |
| 226 | bool isConstructor(VM&) const; |
| 227 | bool isConstructor(VM&, ConstructType&, ConstructData&) const; |
| 228 | bool isUndefined() const; |
| 229 | bool isNull() const; |
| 230 | bool isUndefinedOrNull() const; |
| 231 | bool isBoolean() const; |
| 232 | bool isAnyInt() const; |
| 233 | bool isUInt32AsAnyInt() const; |
| 234 | bool isInt32AsAnyInt() const; |
| 235 | bool isNumber() const; |
| 236 | bool isString() const; |
| 237 | bool isBigInt() const; |
| 238 | bool isSymbol() const; |
| 239 | bool isPrimitive() const; |
| 240 | bool isGetterSetter() const; |
| 241 | bool isCustomGetterSetter() const; |
| 242 | bool isObject() const; |
| 243 | bool inherits(VM&, const ClassInfo*) const; |
| 244 | template<typename Target> bool inherits(VM&) const; |
| 245 | const ClassInfo* classInfoOrNull(VM&) const; |
| 246 | |
| 247 | // Extracting the value. |
| 248 | bool getString(ExecState*, WTF::String&) const; |
| 249 | WTF::String getString(ExecState*) const; // null string if not a string |
| 250 | JSObject* getObject() const; // 0 if not an object |
| 251 | |
| 252 | // Extracting integer values. |
| 253 | bool getUInt32(uint32_t&) const; |
| 254 | |
| 255 | // Basic conversions. |
| 256 | JSValue toPrimitive(ExecState*, PreferredPrimitiveType = NoPreference) const; |
| 257 | bool getPrimitiveNumber(ExecState*, double& number, JSValue&); |
| 258 | |
| 259 | bool toBoolean(ExecState*) const; |
| 260 | TriState pureToBoolean() const; |
| 261 | |
| 262 | // toNumber conversion is expected to be side effect free if an exception has |
| 263 | // been set in the ExecState already. |
| 264 | double toNumber(ExecState*) const; |
| 265 | |
| 266 | Variant<JSBigInt*, double> toNumeric(ExecState*) const; |
| 267 | Variant<JSBigInt*, int32_t> toBigIntOrInt32(ExecState*) const; |
| 268 | |
| 269 | // toNumber conversion if it can be done without side effects. |
| 270 | Optional<double> toNumberFromPrimitive() const; |
| 271 | |
| 272 | JSString* toString(ExecState*) const; // On exception, this returns the empty string. |
| 273 | JSString* toStringOrNull(ExecState*) const; // On exception, this returns null, to make exception checks faster. |
| 274 | Identifier toPropertyKey(ExecState*) const; |
| 275 | WTF::String toWTFString(ExecState*) const; |
| 276 | JSObject* toObject(ExecState*) const; |
| 277 | JSObject* toObject(ExecState*, JSGlobalObject*) const; |
| 278 | |
| 279 | // Integer conversions. |
| 280 | JS_EXPORT_PRIVATE double toInteger(ExecState*) const; |
| 281 | JS_EXPORT_PRIVATE double toIntegerPreserveNaN(ExecState*) const; |
| 282 | int32_t toInt32(ExecState*) const; |
| 283 | uint32_t toUInt32(ExecState*) const; |
| 284 | uint32_t toIndex(ExecState*, const char* errorName) const; |
| 285 | double toLength(ExecState*) const; |
| 286 | |
| 287 | // Floating point conversions (this is a convenience function for WebCore; |
| 288 | // single precision float is not a representation used in JS or JSC). |
| 289 | float toFloat(ExecState* exec) const { return static_cast<float>(toNumber(exec)); } |
| 290 | |
| 291 | // Object operations, with the toObject operation included. |
| 292 | JSValue get(ExecState*, PropertyName) const; |
| 293 | JSValue get(ExecState*, PropertyName, PropertySlot&) const; |
| 294 | JSValue get(ExecState*, unsigned propertyName) const; |
| 295 | JSValue get(ExecState*, unsigned propertyName, PropertySlot&) const; |
| 296 | JSValue get(ExecState*, uint64_t propertyName) const; |
| 297 | |
| 298 | bool getPropertySlot(ExecState*, PropertyName, PropertySlot&) const; |
| 299 | template<typename CallbackWhenNoException> typename std::result_of<CallbackWhenNoException(bool, PropertySlot&)>::type getPropertySlot(ExecState*, PropertyName, CallbackWhenNoException) const; |
| 300 | template<typename CallbackWhenNoException> typename std::result_of<CallbackWhenNoException(bool, PropertySlot&)>::type getPropertySlot(ExecState*, PropertyName, PropertySlot&, CallbackWhenNoException) const; |
| 301 | |
| 302 | bool getOwnPropertySlot(ExecState*, PropertyName, PropertySlot&) const; |
| 303 | |
| 304 | bool put(ExecState*, PropertyName, JSValue, PutPropertySlot&); |
| 305 | bool putInline(ExecState*, PropertyName, JSValue, PutPropertySlot&); |
| 306 | JS_EXPORT_PRIVATE bool putToPrimitive(ExecState*, PropertyName, JSValue, PutPropertySlot&); |
| 307 | JS_EXPORT_PRIVATE bool putToPrimitiveByIndex(ExecState*, unsigned propertyName, JSValue, bool shouldThrow); |
| 308 | bool putByIndex(ExecState*, unsigned propertyName, JSValue, bool shouldThrow); |
| 309 | |
| 310 | JSValue toThis(ExecState*, ECMAMode) const; |
| 311 | |
| 312 | static bool equal(ExecState*, JSValue v1, JSValue v2); |
| 313 | static bool equalSlowCase(ExecState*, JSValue v1, JSValue v2); |
| 314 | static bool equalSlowCaseInline(ExecState*, JSValue v1, JSValue v2); |
| 315 | static bool strictEqual(ExecState*, JSValue v1, JSValue v2); |
| 316 | static bool strictEqualSlowCase(ExecState*, JSValue v1, JSValue v2); |
| 317 | static bool strictEqualSlowCaseInline(ExecState*, JSValue v1, JSValue v2); |
| 318 | static TriState pureStrictEqual(JSValue v1, JSValue v2); |
| 319 | |
| 320 | bool isCell() const; |
| 321 | JSCell* asCell() const; |
| 322 | JS_EXPORT_PRIVATE bool isValidCallee(); |
| 323 | |
| 324 | Structure* structureOrNull() const; |
| 325 | JSValue structureOrUndefined() const; |
| 326 | |
| 327 | JS_EXPORT_PRIVATE void dump(PrintStream&) const; |
| 328 | void dumpInContext(PrintStream&, DumpContext*) const; |
| 329 | void dumpInContextAssumingStructure(PrintStream&, DumpContext*, Structure*) const; |
| 330 | void dumpForBacktrace(PrintStream&) const; |
| 331 | |
| 332 | JS_EXPORT_PRIVATE JSObject* synthesizePrototype(ExecState*) const; |
| 333 | bool requireObjectCoercible(ExecState*) const; |
| 334 | |
| 335 | // Constants used for Int52. Int52 isn't part of JSValue right now, but JSValues may be |
| 336 | // converted to Int52s and back again. |
| 337 | static constexpr const unsigned numberOfInt52Bits = 52; |
| 338 | static constexpr const int64_t notInt52 = static_cast<int64_t>(1) << numberOfInt52Bits; |
| 339 | static constexpr const unsigned int52ShiftAmount = 12; |
| 340 | |
| 341 | static ptrdiff_t offsetOfPayload() { return OBJECT_OFFSETOF(JSValue, u.asBits.payload); } |
| 342 | static ptrdiff_t offsetOfTag() { return OBJECT_OFFSETOF(JSValue, u.asBits.tag); } |
| 343 | |
| 344 | #if USE(JSVALUE32_64) |
| 345 | /* |
| 346 | * On 32-bit platforms USE(JSVALUE32_64) should be defined, and we use a NaN-encoded |
| 347 | * form for immediates. |
| 348 | * |
| 349 | * The encoding makes use of unused NaN space in the IEEE754 representation. Any value |
| 350 | * with the top 13 bits set represents a QNaN (with the sign bit set). QNaN values |
| 351 | * can encode a 51-bit payload. Hardware produced and C-library payloads typically |
| 352 | * have a payload of zero. We assume that non-zero payloads are available to encode |
| 353 | * pointer and integer values. Since any 64-bit bit pattern where the top 15 bits are |
| 354 | * all set represents a NaN with a non-zero payload, we can use this space in the NaN |
| 355 | * ranges to encode other values (however there are also other ranges of NaN space that |
| 356 | * could have been selected). |
| 357 | * |
| 358 | * For JSValues that do not contain a double value, the high 32 bits contain the tag |
| 359 | * values listed in the enums below, which all correspond to NaN-space. In the case of |
| 360 | * cell, integer and bool values the lower 32 bits (the 'payload') contain the pointer |
| 361 | * integer or boolean value; in the case of all other tags the payload is 0. |
| 362 | */ |
| 363 | uint32_t tag() const; |
| 364 | int32_t payload() const; |
| 365 | |
| 366 | // This should only be used by the LLInt C Loop interpreter and OSRExit code who needs |
| 367 | // synthesize JSValue from its "register"s holding tag and payload values. |
| 368 | explicit JSValue(int32_t tag, int32_t payload); |
| 369 | |
| 370 | #elif USE(JSVALUE64) |
| 371 | /* |
| 372 | * On 64-bit platforms USE(JSVALUE64) should be defined, and we use a NaN-encoded |
| 373 | * form for immediates. |
| 374 | * |
| 375 | * The encoding makes use of unused NaN space in the IEEE754 representation. Any value |
| 376 | * with the top 13 bits set represents a QNaN (with the sign bit set). QNaN values |
| 377 | * can encode a 51-bit payload. Hardware produced and C-library payloads typically |
| 378 | * have a payload of zero. We assume that non-zero payloads are available to encode |
| 379 | * pointer and integer values. Since any 64-bit bit pattern where the top 15 bits are |
| 380 | * all set represents a NaN with a non-zero payload, we can use this space in the NaN |
| 381 | * ranges to encode other values (however there are also other ranges of NaN space that |
| 382 | * could have been selected). |
| 383 | * |
| 384 | * This range of NaN space is represented by 64-bit numbers begining with the 16-bit |
| 385 | * hex patterns 0xFFFE and 0xFFFF - we rely on the fact that no valid double-precision |
| 386 | * numbers will fall in these ranges. |
| 387 | * |
| 388 | * The top 16-bits denote the type of the encoded JSValue: |
| 389 | * |
| 390 | * Pointer { 0000:PPPP:PPPP:PPPP |
| 391 | * / 0001:****:****:**** |
| 392 | * Double { ... |
| 393 | * \ FFFE:****:****:**** |
| 394 | * Integer { FFFF:0000:IIII:IIII |
| 395 | * |
| 396 | * The scheme we have implemented encodes double precision values by performing a |
| 397 | * 64-bit integer addition of the value 2^48 to the number. After this manipulation |
| 398 | * no encoded double-precision value will begin with the pattern 0x0000 or 0xFFFF. |
| 399 | * Values must be decoded by reversing this operation before subsequent floating point |
| 400 | * operations may be peformed. |
| 401 | * |
| 402 | * 32-bit signed integers are marked with the 16-bit tag 0xFFFF. |
| 403 | * |
| 404 | * The tag 0x0000 denotes a pointer, or another form of tagged immediate. Boolean, |
| 405 | * null and undefined values are represented by specific, invalid pointer values: |
| 406 | * |
| 407 | * False: 0x06 |
| 408 | * True: 0x07 |
| 409 | * Undefined: 0x0a |
| 410 | * Null: 0x02 |
| 411 | * |
| 412 | * These values have the following properties: |
| 413 | * - Bit 1 (TagBitTypeOther) is set for all four values, allowing real pointers to be |
| 414 | * quickly distinguished from all immediate values, including these invalid pointers. |
| 415 | * - With bit 3 is masked out (TagBitUndefined) Undefined and Null share the |
| 416 | * same value, allowing null & undefined to be quickly detected. |
| 417 | * |
| 418 | * No valid JSValue will have the bit pattern 0x0, this is used to represent array |
| 419 | * holes, and as a C++ 'no value' result (e.g. JSValue() has an internal value of 0). |
| 420 | */ |
| 421 | |
| 422 | // These values are #defines since using static const integers here is a ~1% regression! |
| 423 | |
| 424 | // This value is 2^48, used to encode doubles such that the encoded value will begin |
| 425 | // with a 16-bit pattern within the range 0x0001..0xFFFE. |
| 426 | #define DoubleEncodeOffset 0x1000000000000ll |
| 427 | // If all bits in the mask are set, this indicates an integer number, |
| 428 | // if any but not all are set this value is a double precision number. |
| 429 | #define TagTypeNumber 0xffff000000000000ll |
| 430 | |
| 431 | // All non-numeric (bool, null, undefined) immediates have bit 2 set. |
| 432 | #define TagBitTypeOther 0x2ll |
| 433 | #define TagBitBool 0x4ll |
| 434 | #define TagBitUndefined 0x8ll |
| 435 | // Combined integer value for non-numeric immediates. |
| 436 | #define ValueFalse (TagBitTypeOther | TagBitBool | false) |
| 437 | #define ValueTrue (TagBitTypeOther | TagBitBool | true) |
| 438 | #define ValueUndefined (TagBitTypeOther | TagBitUndefined) |
| 439 | #define ValueNull (TagBitTypeOther) |
| 440 | |
| 441 | // TagMask is used to check for all types of immediate values (either number or 'other'). |
| 442 | #define TagMask (TagTypeNumber | TagBitTypeOther) |
| 443 | |
| 444 | // These special values are never visible to JavaScript code; Empty is used to represent |
| 445 | // Array holes, and for uninitialized JSValues. Deleted is used in hash table code. |
| 446 | // These values would map to cell types in the JSValue encoding, but not valid GC cell |
| 447 | // pointer should have either of these values (Empty is null, deleted is at an invalid |
| 448 | // alignment for a GC cell, and in the zero page). |
| 449 | #define ValueEmpty 0x0ll |
| 450 | #define ValueDeleted 0x4ll |
| 451 | |
| 452 | #define TagBitsWasm (TagBitTypeOther | 0x1) |
| 453 | #define TagWasmMask (TagTypeNumber | 0x7) |
| 454 | // We tag Wasm non-JSCell pointers with a 3 at the bottom. We can test if a 64-bit JSValue pattern |
| 455 | // is a Wasm callee by masking the upper 16 bits and the lower 3 bits, and seeing if |
| 456 | // the resulting value is 3. The full test is: x & TagWasmMask == TagBitsWasm |
| 457 | // This works because the lower 3 bits of the non-number immediate values are as follows: |
| 458 | // undefined: 0b010 |
| 459 | // null: 0b010 |
| 460 | // true: 0b111 |
| 461 | // false: 0b110 |
| 462 | // The test rejects all of these because none have just the value 3 in their lower 3 bits. |
| 463 | // The test rejects all numbers because they have non-zero upper 16 bits. |
| 464 | // The test also rejects normal cells because they won't have the number 3 as |
| 465 | // their lower 3 bits. Note, this bit pattern also allows the normal JSValue isCell(), etc, |
| 466 | // predicates to work on a Wasm::Callee because the various tests will fail if you |
| 467 | // bit casted a boxed Wasm::Callee* to a JSValue. isCell() would fail since it sees |
| 468 | // TagBitTypeOther. The other tests also trivially fail, since it won't be a number, |
| 469 | // and it won't be equal to null, undefined, true, or false. The isBoolean() predicate |
| 470 | // will fail because we won't have TagBitBool set. |
| 471 | #endif |
| 472 | |
| 473 | private: |
| 474 | template <class T> JSValue(WriteBarrierBase<T, WriteBarrierTraitsSelect<T>>); |
| 475 | |
| 476 | enum HashTableDeletedValueTag { HashTableDeletedValue }; |
| 477 | JSValue(HashTableDeletedValueTag); |
| 478 | |
| 479 | inline const JSValue asValue() const { return *this; } |
| 480 | JS_EXPORT_PRIVATE double toNumberSlowCase(ExecState*) const; |
| 481 | JS_EXPORT_PRIVATE JSString* toStringSlowCase(ExecState*, bool returnEmptyStringOnError) const; |
| 482 | JS_EXPORT_PRIVATE WTF::String toWTFStringSlowCase(ExecState*) const; |
| 483 | JS_EXPORT_PRIVATE JSObject* toObjectSlowCase(ExecState*, JSGlobalObject*) const; |
| 484 | JS_EXPORT_PRIVATE JSValue toThisSlowCase(ExecState*, ECMAMode) const; |
| 485 | |
| 486 | EncodedValueDescriptor u; |
| 487 | }; |
| 488 | |
| 489 | typedef IntHash<EncodedJSValue> EncodedJSValueHash; |
| 490 | |
| 491 | #if USE(JSVALUE32_64) |
| 492 | struct EncodedJSValueHashTraits : HashTraits<EncodedJSValue> { |
| 493 | static const bool emptyValueIsZero = false; |
| 494 | static EncodedJSValue emptyValue() { return JSValue::encode(JSValue()); } |
| 495 | static void constructDeletedValue(EncodedJSValue& slot) { slot = JSValue::encode(JSValue(JSValue::HashTableDeletedValue)); } |
| 496 | static bool isDeletedValue(EncodedJSValue value) { return value == JSValue::encode(JSValue(JSValue::HashTableDeletedValue)); } |
| 497 | }; |
| 498 | #else |
| 499 | struct EncodedJSValueHashTraits : HashTraits<EncodedJSValue> { |
| 500 | static void constructDeletedValue(EncodedJSValue& slot) { slot = JSValue::encode(JSValue(JSValue::HashTableDeletedValue)); } |
| 501 | static bool isDeletedValue(EncodedJSValue value) { return value == JSValue::encode(JSValue(JSValue::HashTableDeletedValue)); } |
| 502 | }; |
| 503 | #endif |
| 504 | |
| 505 | typedef std::pair<EncodedJSValue, SourceCodeRepresentation> EncodedJSValueWithRepresentation; |
| 506 | |
| 507 | struct EncodedJSValueWithRepresentationHashTraits : HashTraits<EncodedJSValueWithRepresentation> { |
| 508 | static const bool emptyValueIsZero = false; |
| 509 | static EncodedJSValueWithRepresentation emptyValue() { return std::make_pair(JSValue::encode(JSValue()), SourceCodeRepresentation::Other); } |
| 510 | static void constructDeletedValue(EncodedJSValueWithRepresentation& slot) { slot = std::make_pair(JSValue::encode(JSValue(JSValue::HashTableDeletedValue)), SourceCodeRepresentation::Other); } |
| 511 | static bool isDeletedValue(EncodedJSValueWithRepresentation value) { return value == std::make_pair(JSValue::encode(JSValue(JSValue::HashTableDeletedValue)), SourceCodeRepresentation::Other); } |
| 512 | }; |
| 513 | |
| 514 | struct EncodedJSValueWithRepresentationHash { |
| 515 | static unsigned hash(const EncodedJSValueWithRepresentation& value) |
| 516 | { |
| 517 | return WTF::pairIntHash(EncodedJSValueHash::hash(value.first), IntHash<SourceCodeRepresentation>::hash(value.second)); |
| 518 | } |
| 519 | static bool equal(const EncodedJSValueWithRepresentation& a, const EncodedJSValueWithRepresentation& b) |
| 520 | { |
| 521 | return a == b; |
| 522 | } |
| 523 | static const bool safeToCompareToEmptyOrDeleted = true; |
| 524 | }; |
| 525 | |
| 526 | // Stand-alone helper functions. |
| 527 | inline JSValue jsNull() |
| 528 | { |
| 529 | return JSValue(JSValue::JSNull); |
| 530 | } |
| 531 | |
| 532 | inline JSValue jsUndefined() |
| 533 | { |
| 534 | return JSValue(JSValue::JSUndefined); |
| 535 | } |
| 536 | |
| 537 | inline JSValue jsTDZValue() |
| 538 | { |
| 539 | return JSValue(); |
| 540 | } |
| 541 | |
| 542 | inline JSValue jsBoolean(bool b) |
| 543 | { |
| 544 | return b ? JSValue(JSValue::JSTrue) : JSValue(JSValue::JSFalse); |
| 545 | } |
| 546 | |
| 547 | ALWAYS_INLINE JSValue jsDoubleNumber(double d) |
| 548 | { |
| 549 | ASSERT(JSValue(JSValue::EncodeAsDouble, d).isNumber()); |
| 550 | return JSValue(JSValue::EncodeAsDouble, d); |
| 551 | } |
| 552 | |
| 553 | ALWAYS_INLINE JSValue jsNumber(double d) |
| 554 | { |
| 555 | ASSERT(JSValue(d).isNumber()); |
| 556 | ASSERT(!isImpureNaN(d)); |
| 557 | return JSValue(d); |
| 558 | } |
| 559 | |
| 560 | ALWAYS_INLINE JSValue jsNumber(const MediaTime& t) |
| 561 | { |
| 562 | return jsNumber(t.toDouble()); |
| 563 | } |
| 564 | |
| 565 | ALWAYS_INLINE JSValue jsNumber(char i) |
| 566 | { |
| 567 | return JSValue(i); |
| 568 | } |
| 569 | |
| 570 | ALWAYS_INLINE JSValue jsNumber(unsigned char i) |
| 571 | { |
| 572 | return JSValue(i); |
| 573 | } |
| 574 | |
| 575 | ALWAYS_INLINE JSValue jsNumber(short i) |
| 576 | { |
| 577 | return JSValue(i); |
| 578 | } |
| 579 | |
| 580 | ALWAYS_INLINE JSValue jsNumber(unsigned short i) |
| 581 | { |
| 582 | return JSValue(i); |
| 583 | } |
| 584 | |
| 585 | ALWAYS_INLINE JSValue jsNumber(int i) |
| 586 | { |
| 587 | return JSValue(i); |
| 588 | } |
| 589 | |
| 590 | ALWAYS_INLINE JSValue jsNumber(unsigned i) |
| 591 | { |
| 592 | return JSValue(i); |
| 593 | } |
| 594 | |
| 595 | ALWAYS_INLINE JSValue jsNumber(long i) |
| 596 | { |
| 597 | return JSValue(i); |
| 598 | } |
| 599 | |
| 600 | ALWAYS_INLINE JSValue jsNumber(unsigned long i) |
| 601 | { |
| 602 | return JSValue(i); |
| 603 | } |
| 604 | |
| 605 | ALWAYS_INLINE JSValue jsNumber(long long i) |
| 606 | { |
| 607 | return JSValue(i); |
| 608 | } |
| 609 | |
| 610 | ALWAYS_INLINE JSValue jsNumber(unsigned long long i) |
| 611 | { |
| 612 | return JSValue(i); |
| 613 | } |
| 614 | |
| 615 | ALWAYS_INLINE EncodedJSValue encodedJSUndefined() |
| 616 | { |
| 617 | return JSValue::encode(jsUndefined()); |
| 618 | } |
| 619 | |
| 620 | ALWAYS_INLINE EncodedJSValue encodedJSValue() |
| 621 | { |
| 622 | return JSValue::encode(JSValue()); |
| 623 | } |
| 624 | |
| 625 | inline bool operator==(const JSValue a, const JSCell* b) { return a == JSValue(b); } |
| 626 | inline bool operator==(const JSCell* a, const JSValue b) { return JSValue(a) == b; } |
| 627 | |
| 628 | inline bool operator!=(const JSValue a, const JSCell* b) { return a != JSValue(b); } |
| 629 | inline bool operator!=(const JSCell* a, const JSValue b) { return JSValue(a) != b; } |
| 630 | |
| 631 | |
| 632 | bool isThisValueAltered(const PutPropertySlot&, JSObject* baseObject); |
| 633 | |
| 634 | // See section 7.2.9: https://tc39.github.io/ecma262/#sec-samevalue |
| 635 | bool sameValue(ExecState*, JSValue a, JSValue b); |
| 636 | |
| 637 | } // namespace JSC |
| 638 | |