objects.h.svn-base

Google浏览器V8内核代码

// Copyright 2006-2008 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 "builtins.h"
#include "code-stubs.h"
#include "smart-pointer.h"
#include "unicode-inl.h"

//
// All object types in the V8 JavaScript are described in this file.
//
// Inheritance hierarchy:
//   - Object
//     - Smi          (immediate small integer)
//     - Failure      (immediate for marking failed operation)
//     - HeapObject   (superclass for everything allocated in the heap)
//       - JSObject
//         - JSArray
//         - JSRegExp
//         - JSFunction
//         - GlobalObject
//           - JSGlobalObject
//           - JSBuiltinsObject
//         - JSValue
//         - Script
//       - Array
//         - ByteArray
//         - FixedArray
//           - DescriptorArray
//           - HashTable
//             - Dictionary
//             - SymbolTable
//           - Context
//           - GlobalContext
//       - String
//         - SeqString
//           - AsciiString
//           - TwoByteString
//         - ConsString
//         - SlicedString
//         - ExternalString
//           - ExternalAsciiString
//           - ExternalTwoByteString
//       - HeapNumber
//       - Code
//       - Map
//       - Oddball
//       - Proxy
//       - SharedFunctionInfo
//       - Struct
//         - AccessorInfo
//         - AccessCheckInfo
//         - InterceptorInfo
//         - CallHandlerInfo
//         - FunctionTemplateInfo
//         - ObjectTemplateInfo
//         - SignatureInfo
//         - TypeSwitchInfo
//         - DebugInfo
//         - BreakPointInfo
//
// Formats of Object*:
//  Smi:        [31 bit signed int] 0
//  HeapObject: [32 bit direct pointer] (4 byte aligned) | 01
//  Failure:    [30 bit signed int] 11


// Ecma-262 3rd 8.6.1
enum PropertyAttributes {
  NONE              = v8::None,
  READ_ONLY         = v8::ReadOnly,
  DONT_ENUM         = v8::DontEnum,
  DONT_DELETE       = v8::DontDelete,
  ABSENT            = 16  // Used in runtime to indicate a property is absent.
  // ABSENT can never be stored in or returned from a descriptor's attributes
  // bitfield.  It is only used as a return value meaning the attributes of
  // a non-existent property.
};

namespace v8 { namespace internal {


// PropertyDetails captures type and attributes for a property.
// They are used both in property dictionaries and instance descriptors.
class PropertyDetails BASE_EMBEDDED {
 public:

  PropertyDetails(PropertyAttributes attributes,
                  PropertyType type,
                  int index = 0) {
    ASSERT(TypeField::is_valid(type));
    ASSERT(AttributesField::is_valid(attributes));
    ASSERT(IndexField::is_valid(index));

    value_ = TypeField::encode(type)
        | AttributesField::encode(attributes)
        | IndexField::encode(index);

    ASSERT(type == this->type());
    ASSERT(attributes == this->attributes());
    ASSERT(index == this->index());
  }

  // Conversion for storing details as Object*.
  inline PropertyDetails(Smi* smi);
  inline Smi* AsSmi();

  PropertyType type() { return TypeField::decode(value_); }

  bool IsTransition() {
    PropertyType t = type();
    ASSERT(t != INTERCEPTOR);
    return t == MAP_TRANSITION || t == CONSTANT_TRANSITION;
  }

  PropertyAttributes attributes() { return AttributesField::decode(value_); }

  int index() { return IndexField::decode(value_); }

  static bool IsValidIndex(int index) { return IndexField::is_valid(index); }

  bool IsReadOnly() { return (attributes() & READ_ONLY) != 0; }
  bool IsDontDelete() { return (attributes() & DONT_DELETE) != 0; }
  bool IsDontEnum() { return (attributes() & DONT_ENUM) != 0; }

  // Bit fields in value_ (type, shift, size). Must be public so the
  // constants can be embedded in generated code.
  class TypeField:       public BitField<PropertyType,       0, 3> {};
  class AttributesField: public BitField<PropertyAttributes, 3, 3> {};
  class IndexField:      public BitField<uint32_t,           6, 32-6> {};

  static const int kInitialIndex = 1;

 private:
  uint32_t value_;
};

// 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 length
// (SHORT, MEDIUM, or LONG) is always mentioned.  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 (eg, CONS, SLICED, 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(V)                   \
  V(SHORT_SYMBOL_TYPE)                          \
  V(MEDIUM_SYMBOL_TYPE)                         \
  V(LONG_SYMBOL_TYPE)                           \
  V(SHORT_ASCII_SYMBOL_TYPE)                    \
  V(MEDIUM_ASCII_SYMBOL_TYPE)                   \
  V(LONG_ASCII_SYMBOL_TYPE)                     \
  V(SHORT_CONS_SYMBOL_TYPE)                     \
  V(MEDIUM_CONS_SYMBOL_TYPE)                    \
  V(LONG_CONS_SYMBOL_TYPE)                      \
  V(SHORT_CONS_ASCII_SYMBOL_TYPE)               \
  V(MEDIUM_CONS_ASCII_SYMBOL_TYPE)              \
  V(LONG_CONS_ASCII_SYMBOL_TYPE)                \
  V(SHORT_SLICED_SYMBOL_TYPE)                   \
  V(MEDIUM_SLICED_SYMBOL_TYPE)                  \
  V(LONG_SLICED_SYMBOL_TYPE)                    \
  V(SHORT_SLICED_ASCII_SYMBOL_TYPE)             \
  V(MEDIUM_SLICED_ASCII_SYMBOL_TYPE)            \
  V(LONG_SLICED_ASCII_SYMBOL_TYPE)              \
  V(SHORT_EXTERNAL_SYMBOL_TYPE)                 \
  V(MEDIUM_EXTERNAL_SYMBOL_TYPE)                \
  V(LONG_EXTERNAL_SYMBOL_TYPE)                  \
  V(SHORT_EXTERNAL_ASCII_SYMBOL_TYPE)           \
  V(MEDIUM_EXTERNAL_ASCII_SYMBOL_TYPE)          \
  V(LONG_EXTERNAL_ASCII_SYMBOL_TYPE)            \
  V(SHORT_STRING_TYPE)                          \
  V(MEDIUM_STRING_TYPE)                         \
  V(LONG_STRING_TYPE)                           \
  V(SHORT_ASCII_STRING_TYPE)                    \
  V(MEDIUM_ASCII_STRING_TYPE)                   \
  V(LONG_ASCII_STRING_TYPE)                     \
  V(SHORT_CONS_STRING_TYPE)                     \
  V(MEDIUM_CONS_STRING_TYPE)                    \
  V(LONG_CONS_STRING_TYPE)                      \
  V(SHORT_CONS_ASCII_STRING_TYPE)               \
  V(MEDIUM_CONS_ASCII_STRING_TYPE)              \
  V(LONG_CONS_ASCII_STRING_TYPE)                \
  V(SHORT_SLICED_STRING_TYPE)                   \
  V(MEDIUM_SLICED_STRING_TYPE)                  \
  V(LONG_SLICED_STRING_TYPE)                    \
  V(SHORT_SLICED_ASCII_STRING_TYPE)             \
  V(MEDIUM_SLICED_ASCII_STRING_TYPE)            \
  V(LONG_SLICED_ASCII_STRING_TYPE)              \
  V(SHORT_EXTERNAL_STRING_TYPE)                 \
  V(MEDIUM_EXTERNAL_STRING_TYPE)                \
  V(LONG_EXTERNAL_STRING_TYPE)                  \
  V(SHORT_EXTERNAL_ASCII_STRING_TYPE)           \
  V(MEDIUM_EXTERNAL_ASCII_STRING_TYPE)          \
  V(LONG_EXTERNAL_ASCII_STRING_TYPE)            \
  V(LONG_PRIVATE_EXTERNAL_ASCII_STRING_TYPE)    \
                                                \
  V(MAP_TYPE)                                   \
  V(HEAP_NUMBER_TYPE)                           \
  V(FIXED_ARRAY_TYPE)                           \
  V(CODE_TYPE)                                  \
  V(ODDBALL_TYPE)                               \
  V(PROXY_TYPE)                                 \
  V(BYTE_ARRAY_TYPE)                            \
  V(FILLER_TYPE)                                \
                                                \
  V(ACCESSOR_INFO_TYPE)                         \
  V(ACCESS_CHECK_INFO_TYPE)                     \
  V(INTERCEPTOR_INFO_TYPE)                      \
  V(SHARED_FUNCTION_INFO_TYPE)                  \
  V(CALL_HANDLER_INFO_TYPE)                     \
  V(FUNCTION_TEMPLATE_INFO_TYPE)                \
  V(OBJECT_TEMPLATE_INFO_TYPE)                  \
  V(SIGNATURE_INFO_TYPE)                        \
  V(TYPE_SWITCH_INFO_TYPE)                      \
  V(DEBUG_INFO_TYPE)                            \
  V(BREAK_POINT_INFO_TYPE)                      \
  V(SCRIPT_TYPE)                                \
                                                \
  V(JS_VALUE_TYPE)                              \
  V(JS_OBJECT_TYPE)                             \
  V(JS_GLOBAL_OBJECT_TYPE)                      \
  V(JS_BUILTINS_OBJECT_TYPE)                    \
  V(JS_ARRAY_TYPE)                              \
  V(JS_REGEXP_TYPE)                             \
                                                \
  V(JS_FUNCTION_TYPE)                           \


// Since string types are not consecutive, this macro is used to
// iterate over them.
#define STRING_TYPE_LIST(V)                                                    \
  V(SHORT_SYMBOL_TYPE, TwoByteString::kHeaderSize, short_symbol)               \
  V(MEDIUM_SYMBOL_TYPE, TwoByteString::kHeaderSize, medium_symbol)             \
  V(LONG_SYMBOL_TYPE, TwoByteString::kHeaderSize, long_symbol)                 \
  V(SHORT_ASCII_SYMBOL_TYPE, AsciiString::kHeaderSize, short_ascii_symbol)     \
  V(MEDIUM_ASCII_SYMBOL_TYPE, AsciiString::kHeaderSize, medium_ascii_symbol)   \
  V(LONG_ASCII_SYMBOL_TYPE, AsciiString::kHeaderSize, long_ascii_symbol)       \
  V(SHORT_CONS_SYMBOL_TYPE, ConsString::kSize, short_cons_symbol)              \
  V(MEDIUM_CONS_SYMBOL_TYPE, ConsString::kSize, medium_cons_symbol)            \
  V(LONG_CONS_SYMBOL_TYPE, ConsString::kSize, long_cons_symbol)                \
  V(SHORT_CONS_ASCII_SYMBOL_TYPE, ConsString::kSize, short_cons_ascii_symbol)  \
  V(MEDIUM_CONS_ASCII_SYMBOL_TYPE, ConsString::kSize, medium_cons_ascii_symbol)\
  V(LONG_CONS_ASCII_SYMBOL_TYPE, ConsString::kSize, long_cons_ascii_symbol)    \
  V(SHORT_SLICED_SYMBOL_TYPE, SlicedString::kSize, short_sliced_symbol)        \
  V(MEDIUM_SLICED_SYMBOL_TYPE, SlicedString::kSize, medium_sliced_symbol)      \
  V(LONG_SLICED_SYMBOL_TYPE, SlicedString::kSize, long_sliced_symbol)          \
  V(SHORT_SLICED_ASCII_SYMBOL_TYPE,                                            \
    SlicedString::kSize,                                                       \
    short_sliced_ascii_symbol)                                                 \
  V(MEDIUM_SLICED_ASCII_SYMBOL_TYPE,                                           \
    SlicedString::kSize,                                                       \
    medium_sliced_ascii_symbol)                                                \
  V(LONG_SLICED_ASCII_SYMBOL_TYPE,                                             \
    SlicedString::kSize,                                                       \
    long_sliced_ascii_symbol)                                                  \
  V(SHORT_EXTERNAL_SYMBOL_TYPE,                                                \
    ExternalTwoByteString::kSize,                                              \
    short_external_symbol)                                                     \
  V(MEDIUM_EXTERNAL_SYMBOL_TYPE,                                               \
    ExternalTwoByteString::kSize,                                              \
    medium_external_symbol)                                                    \
  V(LONG_EXTERNAL_SYMBOL_TYPE,                                                 \
    ExternalTwoByteString::kSize,                                              \
    long_external_symbol)                                                      \
  V(SHORT_EXTERNAL_ASCII_SYMBOL_TYPE,                                          \
    ExternalAsciiString::kSize,                                                \
    short_external_ascii_symbol)                                               \
  V(MEDIUM_EXTERNAL_ASCII_SYMBOL_TYPE,                                         \
    ExternalAsciiString::kSize,                                                \
    medium_external_ascii_symbol)                                              \
  V(LONG_EXTERNAL_ASCII_SYMBOL_TYPE,                                           \
    ExternalAsciiString::kSize,                                                \
    long_external_ascii_symbol)                                                \
  V(SHORT_STRING_TYPE, TwoByteString::kHeaderSize, short_string)               \
  V(MEDIUM_STRING_TYPE, TwoByteString::kHeaderSize, medium_string)             \
  V(LONG_STRING_TYPE, TwoByteString::kHeaderSize, long_string)                 \
  V(SHORT_ASCII_STRING_TYPE, AsciiString::kHeaderSize, short_ascii_string)     \
  V(MEDIUM_ASCII_STRING_TYPE, AsciiString::kHeaderSize, medium_ascii_string)   \
  V(LONG_ASCII_STRING_TYPE, AsciiString::kHeaderSize, long_ascii_string)       \
  V(SHORT_CONS_STRING_TYPE, ConsString::kSize, short_cons_string)              \
  V(MEDIUM_CONS_STRING_TYPE, ConsString::kSize, medium_cons_string)            \
  V(LONG_CONS_STRING_TYPE, ConsString::kSize, long_cons_string)                \
  V(SHORT_CONS_ASCII_STRING_TYPE, ConsString::kSize, short_cons_ascii_string)  \
  V(MEDIUM_CONS_ASCII_STRING_TYPE, ConsString::kSize, medium_cons_ascii_string)\
  V(LONG_CONS_ASCII_STRING_TYPE, ConsString::kSize, long_cons_ascii_string)    \
  V(SHORT_SLICED_STRING_TYPE, SlicedString::kSize, short_sliced_string)        \
  V(MEDIUM_SLICED_STRING_TYPE, SlicedString::kSize, medium_sliced_string)      \
  V(LONG_SLICED_STRING_TYPE, SlicedString::kSize, long_sliced_string)          \
  V(SHORT_SLICED_ASCII_STRING_TYPE,                                            \
    SlicedString::kSize,                                                       \