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#ifndef V8_PROPERTY_DETAILS_H_ 29#define V8_PROPERTY_DETAILS_H_ 30 31#include "../include/v8.h" 32#include "allocation.h" 33#include "utils.h" 34 35// Ecma-262 3rd 8.6.1 36enum PropertyAttributes { 37 NONE = v8::None, 38 READ_ONLY = v8::ReadOnly, 39 DONT_ENUM = v8::DontEnum, 40 DONT_DELETE = v8::DontDelete, 41 ABSENT = 16 // Used in runtime to indicate a property is absent. 42 // ABSENT can never be stored in or returned from a descriptor's attributes 43 // bitfield. It is only used as a return value meaning the attributes of 44 // a non-existent property. 45}; 46 47 48namespace v8 { 49namespace internal { 50 51class Smi; 52 53// Type of properties. 54// Order of properties is significant. 55// Must fit in the BitField PropertyDetails::TypeField. 56// A copy of this is in mirror-debugger.js. 57enum PropertyType { 58 NORMAL = 0, // only in slow mode 59 FIELD = 1, // only in fast mode 60 CONSTANT_FUNCTION = 2, // only in fast mode 61 CALLBACKS = 3, 62 HANDLER = 4, // only in lookup results, not in descriptors 63 INTERCEPTOR = 5, // only in lookup results, not in descriptors 64 // All properties before MAP_TRANSITION are real. 65 MAP_TRANSITION = 6, // only in fast mode 66 ELEMENTS_TRANSITION = 7, 67 CONSTANT_TRANSITION = 8, // only in fast mode 68 NULL_DESCRIPTOR = 9, // only in fast mode 69 // There are no IC stubs for NULL_DESCRIPTORS. Therefore, 70 // NULL_DESCRIPTOR can be used as the type flag for IC stubs for 71 // nonexistent properties. 72 NONEXISTENT = NULL_DESCRIPTOR 73}; 74 75 76// PropertyDetails captures type and attributes for a property. 77// They are used both in property dictionaries and instance descriptors. 78class PropertyDetails BASE_EMBEDDED { 79 public: 80 PropertyDetails(PropertyAttributes attributes, 81 PropertyType type, 82 int index = 0) { 83 ASSERT(TypeField::is_valid(type)); 84 ASSERT(AttributesField::is_valid(attributes)); 85 ASSERT(StorageField::is_valid(index)); 86 87 value_ = TypeField::encode(type) 88 | AttributesField::encode(attributes) 89 | StorageField::encode(index); 90 91 ASSERT(type == this->type()); 92 ASSERT(attributes == this->attributes()); 93 ASSERT(index == this->index()); 94 } 95 96 // Conversion for storing details as Object*. 97 explicit inline PropertyDetails(Smi* smi); 98 inline Smi* AsSmi(); 99 100 PropertyType type() { return TypeField::decode(value_); } 101 102 PropertyAttributes attributes() { return AttributesField::decode(value_); } 103 104 int index() { return StorageField::decode(value_); } 105 106 inline PropertyDetails AsDeleted(); 107 108 static bool IsValidIndex(int index) { 109 return StorageField::is_valid(index); 110 } 111 112 bool IsReadOnly() { return (attributes() & READ_ONLY) != 0; } 113 bool IsDontDelete() { return (attributes() & DONT_DELETE) != 0; } 114 bool IsDontEnum() { return (attributes() & DONT_ENUM) != 0; } 115 bool IsDeleted() { return DeletedField::decode(value_) != 0;} 116 117 // Bit fields in value_ (type, shift, size). Must be public so the 118 // constants can be embedded in generated code. 119 class TypeField: public BitField<PropertyType, 0, 4> {}; 120 class AttributesField: public BitField<PropertyAttributes, 4, 3> {}; 121 class DeletedField: public BitField<uint32_t, 7, 1> {}; 122 class StorageField: public BitField<uint32_t, 8, 32-8> {}; 123 124 static const int kInitialIndex = 1; 125 126 private: 127 uint32_t value_; 128}; 129 130} } // namespace v8::internal 131 132#endif // V8_PROPERTY_DETAILS_H_ 133