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| 1 // Copyright 2012 the V8 project authors. All rights reserved. |
| 2 // Redistribution and use in source and binary forms, with or without |
| 3 // modification, are permitted provided that the following conditions are |
| 4 // met: |
| 5 // |
| 6 // * Redistributions of source code must retain the above copyright |
| 7 // notice, this list of conditions and the following disclaimer. |
| 8 // * Redistributions in binary form must reproduce the above |
| 9 // copyright notice, this list of conditions and the following |
| 10 // disclaimer in the documentation and/or other materials provided |
| 11 // with the distribution. |
| 12 // * Neither the name of Google Inc. nor the names of its |
| 13 // contributors may be used to endorse or promote products derived |
| 14 // from this software without specific prior written permission. |
| 15 // |
| 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 |
| 28 #include "elements-kind.h" |
| 29 |
| 30 #include "api.h" |
| 31 #include "elements.h" |
| 32 #include "objects.h" |
| 33 |
| 34 namespace v8 { |
| 35 namespace internal { |
| 36 |
| 37 |
| 38 void PrintElementsKind(FILE* out, ElementsKind kind) { |
| 39 ElementsAccessor* accessor = ElementsAccessor::ForKind(kind); |
| 40 PrintF(out, "%s", accessor->name()); |
| 41 } |
| 42 |
| 43 |
| 44 ElementsKind GetInitialFastElementsKind() { |
| 45 if (FLAG_packed_arrays) { |
| 46 return FAST_SMI_ELEMENTS; |
| 47 } else { |
| 48 return FAST_HOLEY_SMI_ELEMENTS; |
| 49 } |
| 50 } |
| 51 |
| 52 |
| 53 struct InitializeFastElementsKindSequence { |
| 54 static void Construct( |
| 55 ElementsKind** fast_elements_kind_sequence_ptr) { |
| 56 ElementsKind* fast_elements_kind_sequence = |
| 57 new ElementsKind[kFastElementsKindCount]; |
| 58 *fast_elements_kind_sequence_ptr = fast_elements_kind_sequence; |
| 59 STATIC_ASSERT(FAST_SMI_ELEMENTS == FIRST_FAST_ELEMENTS_KIND); |
| 60 fast_elements_kind_sequence[0] = FAST_SMI_ELEMENTS; |
| 61 fast_elements_kind_sequence[1] = FAST_HOLEY_SMI_ELEMENTS; |
| 62 fast_elements_kind_sequence[2] = FAST_DOUBLE_ELEMENTS; |
| 63 fast_elements_kind_sequence[3] = FAST_HOLEY_DOUBLE_ELEMENTS; |
| 64 fast_elements_kind_sequence[4] = FAST_ELEMENTS; |
| 65 fast_elements_kind_sequence[5] = FAST_HOLEY_ELEMENTS; |
| 66 } |
| 67 }; |
| 68 |
| 69 |
| 70 static LazyInstance<ElementsKind*, |
| 71 InitializeFastElementsKindSequence>::type |
| 72 fast_elements_kind_sequence = LAZY_INSTANCE_INITIALIZER; |
| 73 |
| 74 |
| 75 ElementsKind GetFastElementsKindFromSequenceIndex(int sequence_number) { |
| 76 ASSERT(sequence_number >= 0 && |
| 77 sequence_number < kFastElementsKindCount); |
| 78 return fast_elements_kind_sequence.Get()[sequence_number]; |
| 79 } |
| 80 |
| 81 int GetSequenceIndexFromFastElementsKind(ElementsKind elements_kind) { |
| 82 for (int i = 0; i < kFastElementsKindCount; ++i) { |
| 83 if (fast_elements_kind_sequence.Get()[i] == elements_kind) { |
| 84 return i; |
| 85 } |
| 86 } |
| 87 UNREACHABLE(); |
| 88 return 0; |
| 89 } |
| 90 |
| 91 |
| 92 ElementsKind GetNextMoreGeneralFastElementsKind(ElementsKind elements_kind, |
| 93 bool allow_only_packed) { |
| 94 ASSERT(IsFastElementsKind(elements_kind)); |
| 95 ASSERT(elements_kind != TERMINAL_FAST_ELEMENTS_KIND); |
| 96 while (true) { |
| 97 int index = |
| 98 GetSequenceIndexFromFastElementsKind(elements_kind) + 1; |
| 99 elements_kind = GetFastElementsKindFromSequenceIndex(index); |
| 100 if (!IsFastHoleyElementsKind(elements_kind) || !allow_only_packed) { |
| 101 return elements_kind; |
| 102 } |
| 103 } |
| 104 UNREACHABLE(); |
| 105 return TERMINAL_FAST_ELEMENTS_KIND; |
| 106 } |
| 107 |
| 108 |
| 109 bool IsMoreGeneralElementsKindTransition(ElementsKind from_kind, |
| 110 ElementsKind to_kind) { |
| 111 switch (from_kind) { |
| 112 case FAST_SMI_ELEMENTS: |
| 113 return to_kind != FAST_SMI_ELEMENTS; |
| 114 case FAST_HOLEY_SMI_ELEMENTS: |
| 115 return to_kind != FAST_SMI_ELEMENTS && |
| 116 to_kind != FAST_HOLEY_SMI_ELEMENTS; |
| 117 case FAST_DOUBLE_ELEMENTS: |
| 118 return to_kind != FAST_SMI_ELEMENTS && |
| 119 to_kind != FAST_HOLEY_SMI_ELEMENTS && |
| 120 to_kind != FAST_DOUBLE_ELEMENTS; |
| 121 case FAST_HOLEY_DOUBLE_ELEMENTS: |
| 122 return to_kind == FAST_ELEMENTS || |
| 123 to_kind == FAST_HOLEY_ELEMENTS; |
| 124 case FAST_ELEMENTS: |
| 125 return to_kind == FAST_HOLEY_ELEMENTS; |
| 126 case FAST_HOLEY_ELEMENTS: |
| 127 return false; |
| 128 default: |
| 129 return false; |
| 130 } |
| 131 } |
| 132 |
| 133 |
| 134 } } // namespace v8::internal |
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