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 34namespace v8 { 35namespace internal { 36 37 38const char* ElementsKindToString(ElementsKind kind) { 39 ElementsAccessor* accessor = ElementsAccessor::ForKind(kind); 40 return accessor->name(); 41} 42 43 44void PrintElementsKind(FILE* out, ElementsKind kind) { 45 PrintF(out, "%s", ElementsKindToString(kind)); 46} 47 48 49ElementsKind GetInitialFastElementsKind() { 50 if (FLAG_packed_arrays) { 51 return FAST_SMI_ELEMENTS; 52 } else { 53 return FAST_HOLEY_SMI_ELEMENTS; 54 } 55} 56 57 58struct InitializeFastElementsKindSequence { 59 static void Construct( 60 ElementsKind** fast_elements_kind_sequence_ptr) { 61 ElementsKind* fast_elements_kind_sequence = 62 new ElementsKind[kFastElementsKindCount]; 63 *fast_elements_kind_sequence_ptr = fast_elements_kind_sequence; 64 STATIC_ASSERT(FAST_SMI_ELEMENTS == FIRST_FAST_ELEMENTS_KIND); 65 fast_elements_kind_sequence[0] = FAST_SMI_ELEMENTS; 66 fast_elements_kind_sequence[1] = FAST_HOLEY_SMI_ELEMENTS; 67 fast_elements_kind_sequence[2] = FAST_DOUBLE_ELEMENTS; 68 fast_elements_kind_sequence[3] = FAST_HOLEY_DOUBLE_ELEMENTS; 69 fast_elements_kind_sequence[4] = FAST_ELEMENTS; 70 fast_elements_kind_sequence[5] = FAST_HOLEY_ELEMENTS; 71 } 72}; 73 74 75static LazyInstance<ElementsKind*, 76 InitializeFastElementsKindSequence>::type 77 fast_elements_kind_sequence = LAZY_INSTANCE_INITIALIZER; 78 79 80ElementsKind GetFastElementsKindFromSequenceIndex(int sequence_number) { 81 ASSERT(sequence_number >= 0 && 82 sequence_number < kFastElementsKindCount); 83 return fast_elements_kind_sequence.Get()[sequence_number]; 84} 85 86 87int GetSequenceIndexFromFastElementsKind(ElementsKind elements_kind) { 88 for (int i = 0; i < kFastElementsKindCount; ++i) { 89 if (fast_elements_kind_sequence.Get()[i] == elements_kind) { 90 return i; 91 } 92 } 93 UNREACHABLE(); 94 return 0; 95} 96 97 98ElementsKind GetNextMoreGeneralFastElementsKind(ElementsKind elements_kind, 99 bool allow_only_packed) { 100 ASSERT(IsFastElementsKind(elements_kind)); 101 ASSERT(elements_kind != TERMINAL_FAST_ELEMENTS_KIND); 102 while (true) { 103 int index = 104 GetSequenceIndexFromFastElementsKind(elements_kind) + 1; 105 elements_kind = GetFastElementsKindFromSequenceIndex(index); 106 if (!IsFastHoleyElementsKind(elements_kind) || !allow_only_packed) { 107 return elements_kind; 108 } 109 } 110 UNREACHABLE(); 111 return TERMINAL_FAST_ELEMENTS_KIND; 112} 113 114 115bool IsMoreGeneralElementsKindTransition(ElementsKind from_kind, 116 ElementsKind to_kind) { 117 switch (from_kind) { 118 case FAST_SMI_ELEMENTS: 119 return to_kind != FAST_SMI_ELEMENTS; 120 case FAST_HOLEY_SMI_ELEMENTS: 121 return to_kind != FAST_SMI_ELEMENTS && 122 to_kind != FAST_HOLEY_SMI_ELEMENTS; 123 case FAST_DOUBLE_ELEMENTS: 124 return to_kind != FAST_SMI_ELEMENTS && 125 to_kind != FAST_HOLEY_SMI_ELEMENTS && 126 to_kind != FAST_DOUBLE_ELEMENTS; 127 case FAST_HOLEY_DOUBLE_ELEMENTS: 128 return to_kind == FAST_ELEMENTS || 129 to_kind == FAST_HOLEY_ELEMENTS; 130 case FAST_ELEMENTS: 131 return to_kind == FAST_HOLEY_ELEMENTS; 132 case FAST_HOLEY_ELEMENTS: 133 return false; 134 default: 135 return false; 136 } 137} 138 139 140} } // namespace v8::internal 141