Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 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 | #include "src/elements-kind.h" |
| 6 | |
| 7 | #include "src/api.h" |
| 8 | #include "src/base/lazy-instance.h" |
| 9 | #include "src/elements.h" |
| 10 | #include "src/objects.h" |
| 11 | |
| 12 | namespace v8 { |
| 13 | namespace internal { |
| 14 | |
| 15 | |
| 16 | int ElementsKindToShiftSize(ElementsKind elements_kind) { |
| 17 | switch (elements_kind) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 18 | case UINT8_ELEMENTS: |
| 19 | case INT8_ELEMENTS: |
| 20 | case UINT8_CLAMPED_ELEMENTS: |
| 21 | return 0; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 22 | case UINT16_ELEMENTS: |
| 23 | case INT16_ELEMENTS: |
| 24 | return 1; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 25 | case UINT32_ELEMENTS: |
| 26 | case INT32_ELEMENTS: |
| 27 | case FLOAT32_ELEMENTS: |
| 28 | return 2; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 29 | case FAST_DOUBLE_ELEMENTS: |
| 30 | case FAST_HOLEY_DOUBLE_ELEMENTS: |
| 31 | case FLOAT64_ELEMENTS: |
| 32 | return 3; |
| 33 | case FAST_SMI_ELEMENTS: |
| 34 | case FAST_ELEMENTS: |
| 35 | case FAST_HOLEY_SMI_ELEMENTS: |
| 36 | case FAST_HOLEY_ELEMENTS: |
| 37 | case DICTIONARY_ELEMENTS: |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 38 | case FAST_SLOPPY_ARGUMENTS_ELEMENTS: |
| 39 | case SLOW_SLOPPY_ARGUMENTS_ELEMENTS: |
Ben Murdoch | 097c5b2 | 2016-05-18 11:27:45 +0100 | [diff] [blame] | 40 | case FAST_STRING_WRAPPER_ELEMENTS: |
| 41 | case SLOW_STRING_WRAPPER_ELEMENTS: |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 42 | return kPointerSizeLog2; |
Ben Murdoch | 097c5b2 | 2016-05-18 11:27:45 +0100 | [diff] [blame] | 43 | case NO_ELEMENTS: |
| 44 | UNREACHABLE(); |
| 45 | return 0; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 46 | } |
| 47 | UNREACHABLE(); |
| 48 | return 0; |
| 49 | } |
| 50 | |
| 51 | |
| 52 | int GetDefaultHeaderSizeForElementsKind(ElementsKind elements_kind) { |
| 53 | STATIC_ASSERT(FixedArray::kHeaderSize == FixedDoubleArray::kHeaderSize); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 54 | |
| 55 | if (IsFixedTypedArrayElementsKind(elements_kind)) { |
| 56 | return 0; |
| 57 | } else { |
| 58 | return FixedArray::kHeaderSize - kHeapObjectTag; |
| 59 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 60 | } |
| 61 | |
| 62 | |
| 63 | const char* ElementsKindToString(ElementsKind kind) { |
| 64 | ElementsAccessor* accessor = ElementsAccessor::ForKind(kind); |
| 65 | return accessor->name(); |
| 66 | } |
| 67 | |
| 68 | |
| 69 | struct InitializeFastElementsKindSequence { |
| 70 | static void Construct( |
| 71 | ElementsKind** fast_elements_kind_sequence_ptr) { |
| 72 | ElementsKind* fast_elements_kind_sequence = |
| 73 | new ElementsKind[kFastElementsKindCount]; |
| 74 | *fast_elements_kind_sequence_ptr = fast_elements_kind_sequence; |
| 75 | STATIC_ASSERT(FAST_SMI_ELEMENTS == FIRST_FAST_ELEMENTS_KIND); |
| 76 | fast_elements_kind_sequence[0] = FAST_SMI_ELEMENTS; |
| 77 | fast_elements_kind_sequence[1] = FAST_HOLEY_SMI_ELEMENTS; |
| 78 | fast_elements_kind_sequence[2] = FAST_DOUBLE_ELEMENTS; |
| 79 | fast_elements_kind_sequence[3] = FAST_HOLEY_DOUBLE_ELEMENTS; |
| 80 | fast_elements_kind_sequence[4] = FAST_ELEMENTS; |
| 81 | fast_elements_kind_sequence[5] = FAST_HOLEY_ELEMENTS; |
| 82 | |
| 83 | // Verify that kFastElementsKindPackedToHoley is correct. |
| 84 | STATIC_ASSERT(FAST_SMI_ELEMENTS + kFastElementsKindPackedToHoley == |
| 85 | FAST_HOLEY_SMI_ELEMENTS); |
| 86 | STATIC_ASSERT(FAST_DOUBLE_ELEMENTS + kFastElementsKindPackedToHoley == |
| 87 | FAST_HOLEY_DOUBLE_ELEMENTS); |
| 88 | STATIC_ASSERT(FAST_ELEMENTS + kFastElementsKindPackedToHoley == |
| 89 | FAST_HOLEY_ELEMENTS); |
| 90 | } |
| 91 | }; |
| 92 | |
| 93 | |
| 94 | static base::LazyInstance<ElementsKind*, |
| 95 | InitializeFastElementsKindSequence>::type |
| 96 | fast_elements_kind_sequence = LAZY_INSTANCE_INITIALIZER; |
| 97 | |
| 98 | |
| 99 | ElementsKind GetFastElementsKindFromSequenceIndex(int sequence_number) { |
| 100 | DCHECK(sequence_number >= 0 && |
| 101 | sequence_number < kFastElementsKindCount); |
| 102 | return fast_elements_kind_sequence.Get()[sequence_number]; |
| 103 | } |
| 104 | |
| 105 | |
| 106 | int GetSequenceIndexFromFastElementsKind(ElementsKind elements_kind) { |
| 107 | for (int i = 0; i < kFastElementsKindCount; ++i) { |
| 108 | if (fast_elements_kind_sequence.Get()[i] == elements_kind) { |
| 109 | return i; |
| 110 | } |
| 111 | } |
| 112 | UNREACHABLE(); |
| 113 | return 0; |
| 114 | } |
| 115 | |
| 116 | |
| 117 | ElementsKind GetNextTransitionElementsKind(ElementsKind kind) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 118 | int index = GetSequenceIndexFromFastElementsKind(kind); |
| 119 | return GetFastElementsKindFromSequenceIndex(index + 1); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 120 | } |
| 121 | |
| 122 | |
| 123 | static inline bool IsFastTransitionTarget(ElementsKind elements_kind) { |
| 124 | return IsFastElementsKind(elements_kind) || |
| 125 | elements_kind == DICTIONARY_ELEMENTS; |
| 126 | } |
| 127 | |
| 128 | bool IsMoreGeneralElementsKindTransition(ElementsKind from_kind, |
| 129 | ElementsKind to_kind) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 130 | if (IsFixedTypedArrayElementsKind(from_kind) || |
| 131 | IsFixedTypedArrayElementsKind(to_kind)) { |
| 132 | return false; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 133 | } |
| 134 | if (IsFastElementsKind(from_kind) && IsFastTransitionTarget(to_kind)) { |
| 135 | switch (from_kind) { |
| 136 | case FAST_SMI_ELEMENTS: |
| 137 | return to_kind != FAST_SMI_ELEMENTS; |
| 138 | case FAST_HOLEY_SMI_ELEMENTS: |
| 139 | return to_kind != FAST_SMI_ELEMENTS && |
| 140 | to_kind != FAST_HOLEY_SMI_ELEMENTS; |
| 141 | case FAST_DOUBLE_ELEMENTS: |
| 142 | return to_kind != FAST_SMI_ELEMENTS && |
| 143 | to_kind != FAST_HOLEY_SMI_ELEMENTS && |
| 144 | to_kind != FAST_DOUBLE_ELEMENTS; |
| 145 | case FAST_HOLEY_DOUBLE_ELEMENTS: |
| 146 | return to_kind == FAST_ELEMENTS || |
| 147 | to_kind == FAST_HOLEY_ELEMENTS; |
| 148 | case FAST_ELEMENTS: |
| 149 | return to_kind == FAST_HOLEY_ELEMENTS; |
| 150 | case FAST_HOLEY_ELEMENTS: |
| 151 | return false; |
| 152 | default: |
| 153 | return false; |
| 154 | } |
| 155 | } |
| 156 | return false; |
| 157 | } |
| 158 | |
| 159 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 160 | } // namespace internal |
| 161 | } // namespace v8 |