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 36 enum 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 48 namespace v8 { 49 namespace internal { 50 51 class 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. 57 enum 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. 78 class 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
