| // Copyright 2012 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef V8_OBJECTS_ELEMENTS_KIND_H_ |
| #define V8_OBJECTS_ELEMENTS_KIND_H_ |
| |
| #include "src/base/bits.h" |
| #include "src/base/bounds.h" |
| #include "src/base/macros.h" |
| #include "src/common/checks.h" |
| #include "src/flags/flags.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| // V has parameters (Type, type, TYPE, C type) |
| #define TYPED_ARRAYS(V) \ |
| V(Uint8, uint8, UINT8, uint8_t) \ |
| V(Int8, int8, INT8, int8_t) \ |
| V(Uint16, uint16, UINT16, uint16_t) \ |
| V(Int16, int16, INT16, int16_t) \ |
| V(Uint32, uint32, UINT32, uint32_t) \ |
| V(Int32, int32, INT32, int32_t) \ |
| V(Float32, float32, FLOAT32, float) \ |
| V(Float64, float64, FLOAT64, double) \ |
| V(Uint8Clamped, uint8_clamped, UINT8_CLAMPED, uint8_t) \ |
| V(BigUint64, biguint64, BIGUINT64, uint64_t) \ |
| V(BigInt64, bigint64, BIGINT64, int64_t) |
| |
| enum ElementsKind : uint8_t { |
| // The "fast" kind for elements that only contain SMI values. Must be first |
| // to make it possible to efficiently check maps for this kind. |
| PACKED_SMI_ELEMENTS, |
| HOLEY_SMI_ELEMENTS, |
| |
| // The "fast" kind for tagged values. Must be second to make it possible to |
| // efficiently check maps for this and the PACKED_SMI_ELEMENTS kind |
| // together at once. |
| PACKED_ELEMENTS, |
| HOLEY_ELEMENTS, |
| |
| // The "fast" kind for unwrapped, non-tagged double values. |
| PACKED_DOUBLE_ELEMENTS, |
| HOLEY_DOUBLE_ELEMENTS, |
| |
| // The nonextensible kind for elements. |
| PACKED_NONEXTENSIBLE_ELEMENTS, |
| HOLEY_NONEXTENSIBLE_ELEMENTS, |
| |
| // The sealed kind for elements. |
| PACKED_SEALED_ELEMENTS, |
| HOLEY_SEALED_ELEMENTS, |
| |
| // The frozen kind for elements. |
| PACKED_FROZEN_ELEMENTS, |
| HOLEY_FROZEN_ELEMENTS, |
| |
| // The "slow" kind. |
| DICTIONARY_ELEMENTS, |
| |
| // Elements kind of the "arguments" object (only in sloppy mode). |
| FAST_SLOPPY_ARGUMENTS_ELEMENTS, |
| SLOW_SLOPPY_ARGUMENTS_ELEMENTS, |
| |
| // For string wrapper objects ("new String('...')"), the string's characters |
| // are overlaid onto a regular elements backing store. |
| FAST_STRING_WRAPPER_ELEMENTS, |
| SLOW_STRING_WRAPPER_ELEMENTS, |
| |
| // Fixed typed arrays. |
| #define TYPED_ARRAY_ELEMENTS_KIND(Type, type, TYPE, ctype) TYPE##_ELEMENTS, |
| TYPED_ARRAYS(TYPED_ARRAY_ELEMENTS_KIND) |
| #undef TYPED_ARRAY_ELEMENTS_KIND |
| |
| // Sentinel ElementsKind for objects with no elements. |
| NO_ELEMENTS, |
| |
| // Derived constants from ElementsKind. |
| FIRST_ELEMENTS_KIND = PACKED_SMI_ELEMENTS, |
| LAST_ELEMENTS_KIND = BIGINT64_ELEMENTS, |
| FIRST_FAST_ELEMENTS_KIND = PACKED_SMI_ELEMENTS, |
| LAST_FAST_ELEMENTS_KIND = HOLEY_DOUBLE_ELEMENTS, |
| FIRST_FIXED_TYPED_ARRAY_ELEMENTS_KIND = UINT8_ELEMENTS, |
| LAST_FIXED_TYPED_ARRAY_ELEMENTS_KIND = BIGINT64_ELEMENTS, |
| TERMINAL_FAST_ELEMENTS_KIND = HOLEY_ELEMENTS, |
| FIRST_ANY_NONEXTENSIBLE_ELEMENTS_KIND = PACKED_NONEXTENSIBLE_ELEMENTS, |
| LAST_ANY_NONEXTENSIBLE_ELEMENTS_KIND = HOLEY_FROZEN_ELEMENTS, |
| |
| // Alias for kSystemPointerSize-sized elements |
| #ifdef V8_COMPRESS_POINTERS |
| SYSTEM_POINTER_ELEMENTS = PACKED_DOUBLE_ELEMENTS, |
| #else |
| SYSTEM_POINTER_ELEMENTS = PACKED_ELEMENTS, |
| #endif |
| }; |
| |
| constexpr int kElementsKindCount = LAST_ELEMENTS_KIND - FIRST_ELEMENTS_KIND + 1; |
| constexpr int kFastElementsKindCount = |
| LAST_FAST_ELEMENTS_KIND - FIRST_FAST_ELEMENTS_KIND + 1; |
| |
| // The number to add to a packed elements kind to reach a holey elements kind |
| constexpr int kFastElementsKindPackedToHoley = |
| HOLEY_SMI_ELEMENTS - PACKED_SMI_ELEMENTS; |
| |
| constexpr int kElementsKindBits = 5; |
| STATIC_ASSERT((1 << kElementsKindBits) > LAST_ELEMENTS_KIND); |
| STATIC_ASSERT((1 << (kElementsKindBits - 1)) <= LAST_ELEMENTS_KIND); |
| |
| constexpr int kFastElementsKindBits = 3; |
| STATIC_ASSERT((1 << kFastElementsKindBits) > LAST_FAST_ELEMENTS_KIND); |
| STATIC_ASSERT((1 << (kFastElementsKindBits - 1)) <= LAST_FAST_ELEMENTS_KIND); |
| |
| V8_EXPORT_PRIVATE int ElementsKindToShiftSize(ElementsKind elements_kind); |
| V8_EXPORT_PRIVATE int ElementsKindToByteSize(ElementsKind elements_kind); |
| int GetDefaultHeaderSizeForElementsKind(ElementsKind elements_kind); |
| const char* ElementsKindToString(ElementsKind kind); |
| |
| inline ElementsKind GetInitialFastElementsKind() { return PACKED_SMI_ELEMENTS; } |
| |
| ElementsKind GetFastElementsKindFromSequenceIndex(int sequence_number); |
| int GetSequenceIndexFromFastElementsKind(ElementsKind elements_kind); |
| |
| ElementsKind GetNextTransitionElementsKind(ElementsKind elements_kind); |
| |
| inline bool IsDictionaryElementsKind(ElementsKind kind) { |
| return kind == DICTIONARY_ELEMENTS; |
| } |
| |
| inline bool IsFastArgumentsElementsKind(ElementsKind kind) { |
| return kind == FAST_SLOPPY_ARGUMENTS_ELEMENTS; |
| } |
| |
| inline bool IsSlowArgumentsElementsKind(ElementsKind kind) { |
| return kind == SLOW_SLOPPY_ARGUMENTS_ELEMENTS; |
| } |
| |
| inline bool IsSloppyArgumentsElementsKind(ElementsKind kind) { |
| return base::IsInRange(kind, FAST_SLOPPY_ARGUMENTS_ELEMENTS, |
| SLOW_SLOPPY_ARGUMENTS_ELEMENTS); |
| } |
| |
| inline bool IsStringWrapperElementsKind(ElementsKind kind) { |
| return base::IsInRange(kind, FAST_STRING_WRAPPER_ELEMENTS, |
| SLOW_STRING_WRAPPER_ELEMENTS); |
| } |
| |
| inline bool IsTypedArrayElementsKind(ElementsKind kind) { |
| return base::IsInRange(kind, FIRST_FIXED_TYPED_ARRAY_ELEMENTS_KIND, |
| LAST_FIXED_TYPED_ARRAY_ELEMENTS_KIND); |
| } |
| |
| inline bool IsTerminalElementsKind(ElementsKind kind) { |
| return kind == TERMINAL_FAST_ELEMENTS_KIND || IsTypedArrayElementsKind(kind); |
| } |
| |
| inline bool IsFastElementsKind(ElementsKind kind) { |
| STATIC_ASSERT(FIRST_FAST_ELEMENTS_KIND == 0); |
| return kind <= LAST_FAST_ELEMENTS_KIND; |
| } |
| |
| inline bool IsTransitionElementsKind(ElementsKind kind) { |
| return IsFastElementsKind(kind) || IsTypedArrayElementsKind(kind) || |
| kind == FAST_SLOPPY_ARGUMENTS_ELEMENTS || |
| kind == FAST_STRING_WRAPPER_ELEMENTS; |
| } |
| |
| inline bool IsDoubleElementsKind(ElementsKind kind) { |
| return base::IsInRange(kind, PACKED_DOUBLE_ELEMENTS, HOLEY_DOUBLE_ELEMENTS); |
| } |
| |
| inline bool IsFixedFloatElementsKind(ElementsKind kind) { |
| return kind == FLOAT32_ELEMENTS || kind == FLOAT64_ELEMENTS; |
| } |
| |
| inline bool IsDoubleOrFloatElementsKind(ElementsKind kind) { |
| return IsDoubleElementsKind(kind) || IsFixedFloatElementsKind(kind); |
| } |
| |
| // This predicate is used for disabling respective functionality in builtins. |
| inline bool IsAnyNonextensibleElementsKindUnchecked(ElementsKind kind) { |
| return base::IsInRange(kind, FIRST_ANY_NONEXTENSIBLE_ELEMENTS_KIND, |
| LAST_ANY_NONEXTENSIBLE_ELEMENTS_KIND); |
| } |
| |
| inline bool IsAnyNonextensibleElementsKind(ElementsKind kind) { |
| DCHECK_IMPLIES(IsAnyNonextensibleElementsKindUnchecked(kind), |
| FLAG_enable_sealed_frozen_elements_kind); |
| return IsAnyNonextensibleElementsKindUnchecked(kind); |
| } |
| |
| inline bool IsNonextensibleElementsKind(ElementsKind kind) { |
| DCHECK_IMPLIES(base::IsInRange(kind, PACKED_NONEXTENSIBLE_ELEMENTS, |
| HOLEY_NONEXTENSIBLE_ELEMENTS), |
| FLAG_enable_sealed_frozen_elements_kind); |
| return base::IsInRange(kind, PACKED_NONEXTENSIBLE_ELEMENTS, |
| HOLEY_NONEXTENSIBLE_ELEMENTS); |
| } |
| |
| inline bool IsSealedElementsKind(ElementsKind kind) { |
| DCHECK_IMPLIES( |
| base::IsInRange(kind, PACKED_SEALED_ELEMENTS, HOLEY_SEALED_ELEMENTS), |
| FLAG_enable_sealed_frozen_elements_kind); |
| return base::IsInRange(kind, PACKED_SEALED_ELEMENTS, HOLEY_SEALED_ELEMENTS); |
| } |
| |
| inline bool IsFrozenElementsKind(ElementsKind kind) { |
| DCHECK_IMPLIES( |
| base::IsInRange(kind, PACKED_FROZEN_ELEMENTS, HOLEY_FROZEN_ELEMENTS), |
| FLAG_enable_sealed_frozen_elements_kind); |
| return base::IsInRange(kind, PACKED_FROZEN_ELEMENTS, HOLEY_FROZEN_ELEMENTS); |
| } |
| |
| inline bool IsSmiOrObjectElementsKind(ElementsKind kind) { |
| return base::IsInRange(kind, PACKED_SMI_ELEMENTS, HOLEY_ELEMENTS); |
| } |
| |
| inline bool IsSmiElementsKind(ElementsKind kind) { |
| return base::IsInRange(kind, PACKED_SMI_ELEMENTS, HOLEY_SMI_ELEMENTS); |
| } |
| |
| inline bool IsFastNumberElementsKind(ElementsKind kind) { |
| return IsSmiElementsKind(kind) || IsDoubleElementsKind(kind); |
| } |
| |
| inline bool IsObjectElementsKind(ElementsKind kind) { |
| return base::IsInRange(kind, PACKED_ELEMENTS, HOLEY_ELEMENTS); |
| } |
| |
| inline bool IsAnyHoleyNonextensibleElementsKind(ElementsKind kind) { |
| DCHECK_IMPLIES(kind == HOLEY_NONEXTENSIBLE_ELEMENTS || |
| kind == HOLEY_SEALED_ELEMENTS || |
| kind == HOLEY_FROZEN_ELEMENTS, |
| FLAG_enable_sealed_frozen_elements_kind); |
| return kind == HOLEY_NONEXTENSIBLE_ELEMENTS || |
| kind == HOLEY_SEALED_ELEMENTS || kind == HOLEY_FROZEN_ELEMENTS; |
| } |
| |
| inline bool IsHoleyElementsKind(ElementsKind kind) { |
| return kind % 2 == 1 && kind <= HOLEY_DOUBLE_ELEMENTS; |
| } |
| |
| inline bool IsHoleyElementsKindForRead(ElementsKind kind) { |
| return kind % 2 == 1 && kind <= HOLEY_FROZEN_ELEMENTS; |
| } |
| |
| inline bool IsHoleyOrDictionaryElementsKind(ElementsKind kind) { |
| return IsHoleyElementsKindForRead(kind) || kind == DICTIONARY_ELEMENTS; |
| } |
| |
| inline bool IsFastPackedElementsKind(ElementsKind kind) { |
| return kind % 2 == 0 && kind <= PACKED_DOUBLE_ELEMENTS; |
| } |
| |
| inline ElementsKind GetPackedElementsKind(ElementsKind holey_kind) { |
| if (holey_kind == HOLEY_SMI_ELEMENTS) { |
| return PACKED_SMI_ELEMENTS; |
| } |
| if (holey_kind == HOLEY_DOUBLE_ELEMENTS) { |
| return PACKED_DOUBLE_ELEMENTS; |
| } |
| if (holey_kind == HOLEY_ELEMENTS) { |
| return PACKED_ELEMENTS; |
| } |
| return holey_kind; |
| } |
| |
| inline ElementsKind GetHoleyElementsKind(ElementsKind packed_kind) { |
| if (packed_kind == PACKED_SMI_ELEMENTS) { |
| return HOLEY_SMI_ELEMENTS; |
| } |
| if (packed_kind == PACKED_DOUBLE_ELEMENTS) { |
| return HOLEY_DOUBLE_ELEMENTS; |
| } |
| if (packed_kind == PACKED_ELEMENTS) { |
| return HOLEY_ELEMENTS; |
| } |
| if (packed_kind == PACKED_NONEXTENSIBLE_ELEMENTS) { |
| return HOLEY_NONEXTENSIBLE_ELEMENTS; |
| } |
| return packed_kind; |
| } |
| |
| inline bool UnionElementsKindUptoPackedness(ElementsKind* a_out, |
| ElementsKind b) { |
| // Assert that the union of two ElementKinds can be computed via std::max. |
| static_assert(PACKED_SMI_ELEMENTS < HOLEY_SMI_ELEMENTS, |
| "ElementsKind union not computable via std::max."); |
| static_assert(PACKED_ELEMENTS < HOLEY_ELEMENTS, |
| "ElementsKind union not computable via std::max."); |
| static_assert(PACKED_DOUBLE_ELEMENTS < HOLEY_DOUBLE_ELEMENTS, |
| "ElementsKind union not computable via std::max."); |
| ElementsKind a = *a_out; |
| switch (a) { |
| case HOLEY_SMI_ELEMENTS: |
| case PACKED_SMI_ELEMENTS: |
| if (b == PACKED_SMI_ELEMENTS || b == HOLEY_SMI_ELEMENTS) { |
| *a_out = std::max(a, b); |
| return true; |
| } |
| break; |
| case PACKED_ELEMENTS: |
| case HOLEY_ELEMENTS: |
| if (b == PACKED_ELEMENTS || b == HOLEY_ELEMENTS) { |
| *a_out = std::max(a, b); |
| return true; |
| } |
| break; |
| case PACKED_DOUBLE_ELEMENTS: |
| case HOLEY_DOUBLE_ELEMENTS: |
| if (b == PACKED_DOUBLE_ELEMENTS || b == HOLEY_DOUBLE_ELEMENTS) { |
| *a_out = std::max(a, b); |
| return true; |
| } |
| break; |
| default: |
| break; |
| } |
| return false; |
| } |
| |
| bool UnionElementsKindUptoSize(ElementsKind* a_out, ElementsKind b); |
| |
| inline ElementsKind FastSmiToObjectElementsKind(ElementsKind from_kind) { |
| DCHECK(IsSmiElementsKind(from_kind)); |
| return (from_kind == PACKED_SMI_ELEMENTS) ? PACKED_ELEMENTS : HOLEY_ELEMENTS; |
| } |
| |
| inline bool IsSimpleMapChangeTransition(ElementsKind from_kind, |
| ElementsKind to_kind) { |
| return (GetHoleyElementsKind(from_kind) == to_kind) || |
| (IsSmiElementsKind(from_kind) && IsObjectElementsKind(to_kind)); |
| } |
| |
| bool IsMoreGeneralElementsKindTransition(ElementsKind from_kind, |
| ElementsKind to_kind); |
| |
| inline ElementsKind GetMoreGeneralElementsKind(ElementsKind from_kind, |
| ElementsKind to_kind) { |
| if (IsMoreGeneralElementsKindTransition(from_kind, to_kind)) { |
| return to_kind; |
| } |
| return from_kind; |
| } |
| |
| inline bool IsTransitionableFastElementsKind(ElementsKind from_kind) { |
| return IsFastElementsKind(from_kind) && |
| from_kind != TERMINAL_FAST_ELEMENTS_KIND; |
| } |
| |
| inline bool ElementsKindEqual(ElementsKind a, ElementsKind b) { return a == b; } |
| |
| enum class CompactElementsKind : uint8_t { |
| PACKED_SMI_ELEMENTS = PACKED_SMI_ELEMENTS, |
| HOLEY_SMI_ELEMENTS = HOLEY_SMI_ELEMENTS, |
| |
| PACKED_ELEMENTS = PACKED_ELEMENTS, |
| HOLEY_ELEMENTS = HOLEY_ELEMENTS, |
| |
| PACKED_DOUBLE_ELEMENTS = PACKED_DOUBLE_ELEMENTS, |
| HOLEY_DOUBLE_ELEMENTS = HOLEY_DOUBLE_ELEMENTS, |
| |
| NON_COMPACT_ELEMENTS_KIND |
| }; |
| |
| inline CompactElementsKind ToCompactElementsKind(ElementsKind kind) { |
| if (base::IsInRange(kind, PACKED_SMI_ELEMENTS, HOLEY_DOUBLE_ELEMENTS)) { |
| return static_cast<CompactElementsKind>(kind); |
| } |
| |
| return CompactElementsKind::NON_COMPACT_ELEMENTS_KIND; |
| } |
| |
| const char* CompactElementsKindToString(CompactElementsKind kind); |
| |
| } // namespace internal |
| } // namespace v8 |
| |
| #endif // V8_OBJECTS_ELEMENTS_KIND_H_ |