google V8引擎源码工程 （V8 version 3.14.0.1）

// Copyright 2012 the V8 project authors. All rights reserved. // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following // disclaimer in the documentation and/or other materials provided // with the distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived // from this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #ifndef V8_OBJECTS_H_ #define V8_OBJECTS_H_ #include "allocation.h" #include "builtins.h" #include "elements-kind.h" #include "list.h" #include "property-details.h" #include "smart-pointers.h" #include "unicode-inl.h" #if V8_TARGET_ARCH_ARM #include "arm/constants-arm.h" #elif V8_TARGET_ARCH_MIPS #include "mips/constants-mips.h" #endif #include "v8checks.h" #include "zone.h" // // Most object types in the V8 JavaScript are described in this file. // // Inheritance hierarchy: // - MaybeObject (an object or a failure) // - Failure (immediate for marking failed operation) // - Object // - Smi (immediate small integer) // - HeapObject (superclass for everything allocated in the heap) // - JSReceiver (suitable for property access) // - JSObject // - JSArray // - JSSet // - JSMap // - JSWeakMap // - JSRegExp // - JSFunction // - JSModule // - GlobalObject // - JSGlobalObject // - JSBuiltinsObject // - JSGlobalProxy // - JSValue // - JSDate // - JSMessageObject // - JSProxy // - JSFunctionProxy // - FixedArrayBase // - ByteArray // - FixedArray // - DescriptorArray // - HashTable // - Dictionary // - SymbolTable // - CompilationCacheTable // - CodeCacheHashTable // - MapCache // - Context // - JSFunctionResultCache // - ScopeInfo // - TransitionArray // - FixedDoubleArray // - ExternalArray // - ExternalPixelArray // - ExternalByteArray // - ExternalUnsignedByteArray // - ExternalShortArray // - ExternalUnsignedShortArray // - ExternalIntArray // - ExternalUnsignedIntArray // - ExternalFloatArray // - String // - SeqString // - SeqAsciiString // - SeqTwoByteString // - SlicedString // - ConsString // - ExternalString // - ExternalAsciiString // - ExternalTwoByteString // - HeapNumber // - Code // - Map // - Oddball // - Foreign // - SharedFunctionInfo // - Struct // - AccessorInfo // - AccessorPair // - AccessCheckInfo // - InterceptorInfo // - CallHandlerInfo // - TemplateInfo // - FunctionTemplateInfo // - ObjectTemplateInfo // - Script // - SignatureInfo // - TypeSwitchInfo // - DebugInfo // - BreakPointInfo // - CodeCache // // Formats of Object*: // Smi: [31 bit signed int] 0 // HeapObject: [32 bit direct pointer] (4 byte aligned) | 01 // Failure: [30 bit signed int] 11 namespace v8 { namespace internal { enum CompareMapMode { REQUIRE_EXACT_MAP, ALLOW_ELEMENT_TRANSITION_MAPS }; enum KeyedAccessGrowMode { DO_NOT_ALLOW_JSARRAY_GROWTH, ALLOW_JSARRAY_GROWTH }; // Setter that skips the write barrier if mode is SKIP_WRITE_BARRIER. enum WriteBarrierMode { SKIP_WRITE_BARRIER, UPDATE_WRITE_BARRIER }; // PropertyNormalizationMode is used to specify whether to keep // inobject properties when normalizing properties of a JSObject. enum PropertyNormalizationMode { CLEAR_INOBJECT_PROPERTIES, KEEP_INOBJECT_PROPERTIES }; // NormalizedMapSharingMode is used to specify whether a map may be shared // by different objects with normalized properties. enum NormalizedMapSharingMode { UNIQUE_NORMALIZED_MAP, SHARED_NORMALIZED_MAP }; // Indicates whether a get method should implicitly create the object looked up. enum CreationFlag { ALLOW_CREATION, OMIT_CREATION }; // Indicates whether transitions can be added to a source map or not. enum TransitionFlag { INSERT_TRANSITION, OMIT_TRANSITION }; // Indicates whether the transition is simple: the target map of the transition // either extends the current map with a new property, or it modifies the // property that was added last to the current map. enum SimpleTransitionFlag { SIMPLE_TRANSITION, FULL_TRANSITION }; // Indicates whether we are only interested in the descriptors of a particular // map, or in all descriptors in the descriptor array. enum DescriptorFlag { ALL_DESCRIPTORS, OWN_DESCRIPTORS }; // Instance size sentinel for objects of variable size. const int kVariableSizeSentinel = 0; const int kStubMajorKeyBits = 6; const int kStubMinorKeyBits = kBitsPerInt - kSmiTagSize - kStubMajorKeyBits; // All Maps have a field instance_type containing a InstanceType. // It describes the type of the instances. // // As an example, a JavaScript object is a heap object and its map // instance_type is JS_OBJECT_TYPE. // // The names of the string instance types are intended to systematically // mirror their encoding in the instance_type field of the map. The default // encoding is considered TWO_BYTE. It is not mentioned in the name. ASCII // encoding is mentioned explicitly in the name. Likewise, the default // representation is considered sequential. It is not mentioned in the // name. The other representations (e.g. CONS, EXTERNAL) are explicitly // mentioned. Finally, the string is either a SYMBOL_TYPE (if it is a // symbol) or a STRING_TYPE (if it is not a symbol). // // NOTE: The following things are some that depend on the string types having // instance_types that are less than those of all other types: // HeapObject::Size, HeapObject::IterateBody, the typeof operator, and // Object::IsString. // // NOTE: Everything following JS_VALUE_TYPE is considered a // JSObject for GC purposes. The first four entries here have typeof // 'object', whereas JS_FUNCTION_TYPE has typeof 'function'. #define INSTANCE_TYPE_LIST_ALL(V) \ V(SYMBOL_TYPE) \ V(ASCII_SYMBOL_TYPE) \ V(CONS_SYMBOL_TYPE)