本文详细介绍了V8引擎Heap中的RootObject初始化过程，包括root_数组的索引定义、对象获取、对象设置及其相关的宏定义。RootObject在V8中扮演着重要角色，包含各种类的Map对象和全局关键对象。通过宏定义实现root_数组的存取，分为STRONG_ROOT_LIST、INTERNALIZED_STRING_LIST和STRUCT_LIST三类，其中后两者定义的对象不可写。
Heap类中有一个Object* root_[]，这个数组是在Heap::CreateHeapObjects方法中初始化的，root_数组非常重要，其中包含了各种类的Map对象，和其他非常重要的全局对象。对于root_数组的存取，Heap一以贯之的使用了宏定义的方式
1.root_数组的索引
enum RootListIndex {
#define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex,
STRONG_ROOT_LIST(ROOT_INDEX_DECLARATION)
#undef ROOT_INDEX_DECLARATION
#define STRING_INDEX_DECLARATION(name, str) k##name##RootIndex,
INTERNALIZED_STRING_LIST(STRING_INDEX_DECLARATION)
#undef STRING_DECLARATION
// Utility type maps
#define DECLARE_STRUCT_MAP(NAME, Name, name) k##Name##MapRootIndex,
STRUCT_LIST(DECLARE_STRUCT_MAP)
#undef DECLARE_STRUCT_MAP
kStringTableRootIndex,
kStrongRootListLength = kStringTableRootIndex,
kRootListLength
};
#define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex,
STRONG_ROOT_LIST(ROOT_INDEX_DECLARATION)
#undef ROOT_INDEX_DECLARATION
#define STRING_INDEX_DECLARATION(name, str) k##name##RootIndex,
INTERNALIZED_STRING_LIST(STRING_INDEX_DECLARATION)
#undef STRING_DECLARATION
// Utility type maps
#define DECLARE_STRUCT_MAP(NAME, Name, name) k##Name##MapRootIndex,
STRUCT_LIST(DECLARE_STRUCT_MAP)
#undef DECLARE_STRUCT_MAP
kStringTableRootIndex,
kStrongRootListLength = kStringTableRootIndex,
kRootListLength
};
这里定义了设置获取root_数组所需要的index，它是一个枚举类型
2.root_数组中对象的获取
从上面index的定义，我们可以看到Index被分为三种，分别由STRONG_ROOT_LIST，INTERNALIZED_STRING_LIST和STRUCT_LIST定义的。
我们看如下的宏定义：
#define ROOT_ACCESSOR(type, name, camel_name) \
type* name() { \
return type::cast(roots_[k##camel_name##RootIndex]); \
} \
type* raw_unchecked_##name() { \
return reinterpret_cast<type*>(roots_[k##camel_name##RootIndex]); \
}
type* name() { \
return type::cast(roots_[k##camel_name##RootIndex]); \
} \
type* raw_unchecked_##name() { \
return reinterpret_cast<type*>(roots_[k##camel_name##RootIndex]); \
}
ROOT_LIST(ROOT_ACCESSOR)
#define STRUCT_MAP_ACCESSOR(NAME, Name, name) \
Map* name##_map() { \
return Map::cast(roots_[k##Name##MapRootIndex]); \
}
Map* name##_map() { \
return Map::cast(roots_[k##Name##MapRootIndex]); \
}
STRUCT_LIST(STRUCT_MAP_ACCESSOR)
#define STRING_ACCESSOR(name, str) String* name() { \
return String::cast(roots_[k##name##RootIndex]); \
}
return String::cast(roots_[k##name##RootIndex]); \
}
INTERNALIZED_STRING_LIST(STRING_ACCESSOR)
这三个宏定义了getter函数，用于根据类型和名称获取root中相应的对象，分别对应上面的三种不同类型的index。
这三个宏定义了getter函数，用于根据类型和名称获取root中相应的对象，分别对应上面的三种不同类型的index。
3.root_数组中对象的设置
#define ROOT_ACCESSOR(type, name, camel_name) \
inline void set_##name(type* value) { \
/* The deserializer makes use of the fact that these common roots are */ \
/* never in new space and never on a page that is being compacted. */ \
ASSERT(k##camel_name##RootIndex >= kOldSpaceRoots || !InNewSpace(value)); \
roots_[k##camel_name##RootIndex] = value; \
}
ROOT_LIST(ROOT_ACCESSOR)
inline void set_##name(type* value) { \
/* The deserializer makes use of the fact that these common roots are */ \
/* never in new space and never on a page that is being compacted. */ \
ASSERT(k##camel_name##RootIndex >= kOldSpaceRoots || !InNewSpace(value)); \
roots_[k##camel_name##RootIndex] = value; \
}
ROOT_LIST(ROOT_ACCESSOR)
这个宏显然定义了setter函数，用于设置root_数组中的一些索引的内容。奇怪的是，这里少了上面的两个宏STRUCT_LIST，INTERNALIZED_STRING_LIST，这说明，由这两个宏定义index的root_数组对象是不可写的，相应的，由ROOT_LIST定义index的root_数组对象是可写的。
4.列表宏
这三个宏的定义如下：
heap.h中定义如下两个宏
#define STRONG_ROOT_LIST(V) \
V(Map, byte_array_map, ByteArrayMap) \
V(Map, free_space_map, FreeSpaceMap) \
V(Map, one_pointer_filler_map, OnePointerFillerMap) \
V(Map, two_pointer_filler_map, TwoPointerFillerMap) \
/* Cluster the most popular ones in a few cache lines here at the top. */ \
V(Smi, store_buffer_top, StoreBufferTop) \
V(Oddball, undefined_value, UndefinedValue) \
V(Oddball, the_hole_value, TheHoleValue) \
V(Oddball, null_value, NullValue) \
V(Oddball, true_value, TrueValue) \
V(Oddball, false_value, FalseValue) \
V(Map, global_property_cell_map, GlobalPropertyCellMap) \
V(Map, shared_function_info_map, SharedFunctionInfoMap) \
V(Map, meta_map, MetaMap) \
V(Map, heap_number_map, HeapNumberMap) \
V(Map, native_context_map, NativeContextMap) \
V(Map, fixed_array_map, FixedArrayMap) \
V(Map, code_map, CodeMap) \
V(Map, scope_info_map, ScopeInfoMap) \
V(Map, fixed_cow_array_map, FixedCOWArrayMap) \
V(Map, fixed_double_array_map, FixedDoubleArrayMap) \
V(Object, no_interceptor_result_sentinel, NoInterceptorResultSentinel) \
V(Map, hash_table_map, HashTableMap) \
V(FixedArray, empty_fixed_array, EmptyFixedArray) \
V(ByteArray, empty_byte_array, EmptyByteArray) \
V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray) \
V(Smi, stack_limit, StackLimit) \
V(Oddball, arguments_marker, ArgumentsMarker) \
/* The first 32 roots above this line should be boring from a GC point of */ \
/* view. This means they are never in new space and never on a page that */ \
/* is being compacted. */ \
V(FixedArray, number_string_cache, NumberStringCache) \
V(Object, instanceof_cache_function, InstanceofCacheFunction) \
V(Object, instanceof_cache_map, InstanceofCacheMap) \
V(Object, instanceof_cache_answer, InstanceofCacheAnswer) \
V(FixedArray, single_character_string_cache, SingleCharacterStringCache) \
V(FixedArray, string_split_cache, StringSplitCache) \
V(FixedArray, regexp_multiple_cache, RegExpMultipleCache) \
V(Object, termination_exception, TerminationException) \
V(Smi, hash_seed, HashSeed) \
V(Map, symbol_map, SymbolMap) \
V(Map, string_map, StringMap) \
V(Map, ascii_string_map, AsciiStringMap) \
V(Map, cons_string_map, ConsStringMap) \
V(Map, cons_ascii_string_map, ConsAsciiStringMap) \
V(Map, sliced_string_map, SlicedStringMap) \
V(Map, sliced_ascii_string_map, SlicedAsciiStringMap) \
V(Map, external_string_map, ExternalStringMap) \
V(Map, external_string_with_ascii_data_map, ExternalStringWithAsciiDataMap) \
V(Map, external_ascii_string_map, ExternalAsciiStringMap) \
V(Map, short_external_string_map, ShortExternalStringMap) \
V(Map, \
short_external_string_with_ascii_data_map, \
ShortExternalStringWithAsciiDataMap) \
V(Map, internalized_string_map, InternalizedStringMap) \
V(Map, ascii_internalized_string_map, AsciiInternalizedStringMap) \
V(Map, cons_internalized_string_map, ConsInternalizedStringMap) \
V(Map, cons_ascii_internalized_string_map, ConsAsciiInternalizedStringMap) \
V(Map, \
external_internalized_string_map, \
ExternalInternalizedStringMap) \
V(Map, \
external_internalized_string_with_ascii_data_map, \
ExternalInternalizedStringWithAsciiDataMap) \
V(Map, \
external_ascii_internalized_string_map, \
ExternalAsciiInternalizedStringMap) \
V(Map, \
short_external_internalized_string_map, \
ShortExternalInternalizedStringMap) \
V(Map, \
short_external_internalized_string_with_ascii_data_map, \
ShortExternalInternalizedStringWithAsciiDataMap) \
V(Map, \
short_external_ascii_internalized_string_map, \
ShortExternalAsciiInternalizedStringMap) \
V(Map, short_external_ascii_string_map, ShortExternalAsciiStringMap) \
V(Map, undetectable_string_map, UndetectableStringMap) \
V(Map, undetectable_ascii_string_map, UndetectableAsciiStringMap) \
V(Map, external_pixel_array_map, ExternalPixelArrayMap) \
V(Map, external_byte_array_map, ExternalByteArrayMap) \
V(Map, external_unsigned_byte_array_map, ExternalUnsignedByteArrayMap) \
V(Map, external_short_array_map, ExternalShortArrayMap) \
V(Map, external_unsigned_short_array_map, ExternalUnsignedShortArrayMap) \
V(Map, external_int_array_map, ExternalIntArrayMap) \
V(Map, external_unsigned_int_array_map, ExternalUnsignedIntArrayMap) \
V(Map, external_float_array_map, ExternalFloatArrayMap) \
V(Map, external_double_array_map, ExternalDoubleArrayMap) \
V(Map, non_strict_arguments_elements_map, NonStrictArgumentsElementsMap) \
V(Map, function_context_map, FunctionContextMap) \
V(Map, catch_context_map, CatchContextMap) \
V(Map, with_context_map, WithContextMap) \
V(Map, block_context_map, BlockContextMap) \
V(Map, module_context_map, ModuleContextMap) \
V(Map, global_context_map, GlobalContextMap) \
V(Map, oddball_map, OddballMap) \
V(Map, message_object_map, JSMessageObjectMap) \
V(Map, foreign_map, ForeignMap) \
V(HeapNumber, nan_value, NanValue) \
V(HeapNumber, infinity_value, InfinityValue) \
V(HeapNumber, minus_zero_value, MinusZeroValue) \
V(Map, neander_map, NeanderMap) \
V(JSObject, message_listeners, MessageListeners) \
V(Foreign, prototype_accessors, PrototypeAccessors) \
V(UnseededNumberDictionary, code_stubs, CodeStubs) \
V(UnseededNumberDictionary, non_monomorphic_cache, NonMonomorphicCache) \
V(PolymorphicCodeCache, polymorphic_code_cache, PolymorphicCodeCache) \
V(Code, js_entry_code, JsEntryCode) \
V(Code, js_construct_entry_code, JsConstructEntryCode) \
V(FixedArray, natives_source_cache, NativesSourceCache) \
V(Object, last_script_id, LastScriptId) \
V(Script, empty_script, EmptyScript) \
V(Smi, real_stack_limit, RealStackLimit) \
V(NameDictionary, intrinsic_function_names, IntrinsicFunctionNames) \
V(Smi, arguments_adaptor_deopt_pc_offset, ArgumentsAdaptorDeoptPCOffset) \
V(Smi, construct_stub_deopt_pc_offset, ConstructStubDeoptPCOffset) \
V(Smi, getter_stub_deopt_pc_offset, GetterStubDeoptPCOffset) \
V(Smi, setter_stub_deopt_pc_offset, SetterStubDeoptPCOffset) \
V(JSObject, observation_state, ObservationState) \
V(Map, external_map, ExternalMap)
#define ROOT_LIST(V) \
STRONG_ROOT_LIST(V) \
V(StringTable, string_table, StringTable)
#define INTERNALIZED_STRING_LIST(V) \
V(Array_string, "Array") \
V(Object_string, "Object") \
V(proto_string, "__proto__") \
V(StringImpl_string, "StringImpl") \
V(arguments_string, "arguments") \
V(Arguments_string, "Arguments") \
V(call_string, "call") \
V(apply_string, "apply") \
V(caller_string, "caller") \
V(boolean_string, "boolean") \
V(Boolean_string, "Boolean") \
V(callee_string, "callee") \
V(constructor_string, "constructor") \
V(code_string, ".code") \
V(result_string, ".result") \
V(dot_for_string, ".for.") \
V(catch_var_string, ".catch-var") \
V(empty_string, "") \
V(eval_string, "eval") \
V(function_string, "function") \
V(length_string, "length") \
V(module_string, "module") \
V(name_string, "name") \
V(native_string, "native") \
V(null_string, "null") \
V(number_string, "number") \
V(Number_string, "Number") \
V(nan_string, "NaN") \
V(RegExp_string, "RegExp") \
V(source_string, "source") \
V(global_string, "global") \
V(ignore_case_string, "ignoreCase") \
V(multiline_string, "multiline") \
V(input_string, "input") \
V(index_string, "index") \
V(last_index_string, "lastIndex") \
V(object_string, "object") \
V(prototype_string, "prototype") \
V(string_string, "string") \
V(String_string, "String") \
V(Date_string, "Date") \
V(this_string, "this") \
V(to_string_string, "toString") \
V(char_at_string, "CharAt") \
V(undefined_string, "undefined") \
V(value_of_string, "valueOf") \
V(stack_string, "stack") \
V(InitializeVarGlobal_string, "InitializeVarGlobal") \
V(InitializeConstGlobal_string, "InitializeConstGlobal") \
V(KeyedLoadElementMonomorphic_string, \
"KeyedLoadElementMonomorphic") \
V(KeyedStoreElementMonomorphic_string, \
"KeyedStoreElementMonomorphic") \
V(stack_overflow_string, "kStackOverflowBoilerplate") \
V(illegal_access_string, "illegal access") \
V(out_of_memory_string, "out-of-memory") \
V(illegal_execution_state_string, "illegal execution state") \
V(get_string, "get") \
V(set_string, "set") \
V(map_field_string, "%map") \
V(elements_field_string, "%elements") \
V(length_field_string, "%length") \
V(function_class_string, "Function") \
V(illegal_argument_string, "illegal argument") \
V(MakeReferenceError_string, "MakeReferenceError") \
V(MakeSyntaxError_string, "MakeSyntaxError") \
V(MakeTypeError_string, "MakeTypeError") \
V(invalid_lhs_in_assignment_string, "invalid_lhs_in_assignment") \
V(invalid_lhs_in_for_in_string, "invalid_lhs_in_for_in") \
V(invalid_lhs_in_postfix_op_string, "invalid_lhs_in_postfix_op") \
V(invalid_lhs_in_prefix_op_string, "invalid_lhs_in_prefix_op") \
V(illegal_return_string, "illegal_return") \
V(illegal_break_string, "illegal_break") \
V(illegal_continue_string, "illegal_continue") \
V(unknown_label_string, "unknown_label") \
V(redeclaration_string, "redeclaration") \
V(failure_string, "<failure>") \
V(space_string, " ") \
V(exec_string, "exec") \
V(zero_string, "0") \
V(global_eval_string, "GlobalEval") \
V(identity_hash_string, "v8::IdentityHash") \
V(closure_string, "(closure)") \
V(use_strict_string, "use strict") \
V(dot_string, ".") \
V(anonymous_function_string, "(anonymous function)") \
V(compare_ic_string, "==") \
V(strict_compare_ic_string, "===") \
V(infinity_string, "Infinity") \
V(minus_infinity_string, "-Infinity") \
V(hidden_stack_trace_string, "v8::hidden_stack_trace") \
V(query_colon_string, "(?:)")
V(Map, byte_array_map, ByteArrayMap) \
V(Map, free_space_map, FreeSpaceMap) \
V(Map, one_pointer_filler_map, OnePointerFillerMap) \
V(Map, two_pointer_filler_map, TwoPointerFillerMap) \
/* Cluster the most popular ones in a few cache lines here at the top. */ \
V(Smi, store_buffer_top, StoreBufferTop) \
V(Oddball, undefined_value, UndefinedValue) \
V(Oddball, the_hole_value, TheHoleValue) \
V(Oddball, null_value, NullValue) \
V(Oddball, true_value, TrueValue) \
V(Oddball, false_value, FalseValue) \
V(Map, global_property_cell_map, GlobalPropertyCellMap) \
V(Map, shared_function_info_map, SharedFunctionInfoMap) \
V(Map, meta_map, MetaMap) \
V(Map, heap_number_map, HeapNumberMap) \
V(Map, native_context_map, NativeContextMap) \
V(Map, fixed_array_map, FixedArrayMap) \
V(Map, code_map, CodeMap) \
V(Map, scope_info_map, ScopeInfoMap) \
V(Map, fixed_cow_array_map, FixedCOWArrayMap) \
V(Map, fixed_double_array_map, FixedDoubleArrayMap) \
V(Object, no_interceptor_result_sentinel, NoInterceptorResultSentinel) \
V(Map, hash_table_map, HashTableMap) \
V(FixedArray, empty_fixed_array, EmptyFixedArray) \
V(ByteArray, empty_byte_array, EmptyByteArray) \
V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray) \
V(Smi, stack_limit, StackLimit) \
V(Oddball, arguments_marker, ArgumentsMarker) \
/* The first 32 roots above this line should be boring from a GC point of */ \
/* view. This means they are never in new space and never on a page that */ \
/* is being compacted. */ \
V(FixedArray, number_string_cache, NumberStringCache) \
V(Object, instanceof_cache_function, InstanceofCacheFunction) \
V(Object, instanceof_cache_map, InstanceofCacheMap) \
V(Object, instanceof_cache_answer, InstanceofCacheAnswer) \
V(FixedArray, single_character_string_cache, SingleCharacterStringCache) \
V(FixedArray, string_split_cache, StringSplitCache) \
V(FixedArray, regexp_multiple_cache, RegExpMultipleCache) \
V(Object, termination_exception, TerminationException) \
V(Smi, hash_seed, HashSeed) \
V(Map, symbol_map, SymbolMap) \
V(Map, string_map, StringMap) \
V(Map, ascii_string_map, AsciiStringMap) \
V(Map, cons_string_map, ConsStringMap) \
V(Map, cons_ascii_string_map, ConsAsciiStringMap) \
V(Map, sliced_string_map, SlicedStringMap) \
V(Map, sliced_ascii_string_map, SlicedAsciiStringMap) \
V(Map, external_string_map, ExternalStringMap) \
V(Map, external_string_with_ascii_data_map, ExternalStringWithAsciiDataMap) \
V(Map, external_ascii_string_map, ExternalAsciiStringMap) \
V(Map, short_external_string_map, ShortExternalStringMap) \
V(Map, \
short_external_string_with_ascii_data_map, \
ShortExternalStringWithAsciiDataMap) \
V(Map, internalized_string_map, InternalizedStringMap) \
V(Map, ascii_internalized_string_map, AsciiInternalizedStringMap) \
V(Map, cons_internalized_string_map, ConsInternalizedStringMap) \
V(Map, cons_ascii_internalized_string_map, ConsAsciiInternalizedStringMap) \
V(Map, \
external_internalized_string_map, \
ExternalInternalizedStringMap) \
V(Map, \
external_internalized_string_with_ascii_data_map, \
ExternalInternalizedStringWithAsciiDataMap) \
V(Map, \
external_ascii_internalized_string_map, \
ExternalAsciiInternalizedStringMap) \
V(Map, \
short_external_internalized_string_map, \
ShortExternalInternalizedStringMap) \
V(Map, \
short_external_internalized_string_with_ascii_data_map, \
ShortExternalInternalizedStringWithAsciiDataMap) \
V(Map, \
short_external_ascii_internalized_string_map, \
ShortExternalAsciiInternalizedStringMap) \
V(Map, short_external_ascii_string_map, ShortExternalAsciiStringMap) \
V(Map, undetectable_string_map, UndetectableStringMap) \
V(Map, undetectable_ascii_string_map, UndetectableAsciiStringMap) \
V(Map, external_pixel_array_map, ExternalPixelArrayMap) \
V(Map, external_byte_array_map, ExternalByteArrayMap) \
V(Map, external_unsigned_byte_array_map, ExternalUnsignedByteArrayMap) \
V(Map, external_short_array_map, ExternalShortArrayMap) \
V(Map, external_unsigned_short_array_map, ExternalUnsignedShortArrayMap) \
V(Map, external_int_array_map, ExternalIntArrayMap) \
V(Map, external_unsigned_int_array_map, ExternalUnsignedIntArrayMap) \
V(Map, external_float_array_map, ExternalFloatArrayMap) \
V(Map, external_double_array_map, ExternalDoubleArrayMap) \
V(Map, non_strict_arguments_elements_map, NonStrictArgumentsElementsMap) \
V(Map, function_context_map, FunctionContextMap) \
V(Map, catch_context_map, CatchContextMap) \
V(Map, with_context_map, WithContextMap) \
V(Map, block_context_map, BlockContextMap) \
V(Map, module_context_map, ModuleContextMap) \
V(Map, global_context_map, GlobalContextMap) \
V(Map, oddball_map, OddballMap) \
V(Map, message_object_map, JSMessageObjectMap) \
V(Map, foreign_map, ForeignMap) \
V(HeapNumber, nan_value, NanValue) \
V(HeapNumber, infinity_value, InfinityValue) \
V(HeapNumber, minus_zero_value, MinusZeroValue) \
V(Map, neander_map, NeanderMap) \
V(JSObject, message_listeners, MessageListeners) \
V(Foreign, prototype_accessors, PrototypeAccessors) \
V(UnseededNumberDictionary, code_stubs, CodeStubs) \
V(UnseededNumberDictionary, non_monomorphic_cache, NonMonomorphicCache) \
V(PolymorphicCodeCache, polymorphic_code_cache, PolymorphicCodeCache) \
V(Code, js_entry_code, JsEntryCode) \
V(Code, js_construct_entry_code, JsConstructEntryCode) \
V(FixedArray, natives_source_cache, NativesSourceCache) \
V(Object, last_script_id, LastScriptId) \
V(Script, empty_script, EmptyScript) \
V(Smi, real_stack_limit, RealStackLimit) \
V(NameDictionary, intrinsic_function_names, IntrinsicFunctionNames) \
V(Smi, arguments_adaptor_deopt_pc_offset, ArgumentsAdaptorDeoptPCOffset) \
V(Smi, construct_stub_deopt_pc_offset, ConstructStubDeoptPCOffset) \
V(Smi, getter_stub_deopt_pc_offset, GetterStubDeoptPCOffset) \
V(Smi, setter_stub_deopt_pc_offset, SetterStubDeoptPCOffset) \
V(JSObject, observation_state, ObservationState) \
V(Map, external_map, ExternalMap)
#define ROOT_LIST(V) \
STRONG_ROOT_LIST(V) \
V(StringTable, string_table, StringTable)
#define INTERNALIZED_STRING_LIST(V) \
V(Array_string, "Array") \
V(Object_string, "Object") \
V(proto_string, "__proto__") \
V(StringImpl_string, "StringImpl") \
V(arguments_string, "arguments") \
V(Arguments_string, "Arguments") \
V(call_string, "call") \
V(apply_string, "apply") \
V(caller_string, "caller") \
V(boolean_string, "boolean") \
V(Boolean_string, "Boolean") \
V(callee_string, "callee") \
V(constructor_string, "constructor") \
V(code_string, ".code") \
V(result_string, ".result") \
V(dot_for_string, ".for.") \
V(catch_var_string, ".catch-var") \
V(empty_string, "") \
V(eval_string, "eval") \
V(function_string, "function") \
V(length_string, "length") \
V(module_string, "module") \
V(name_string, "name") \
V(native_string, "native") \
V(null_string, "null") \
V(number_string, "number") \
V(Number_string, "Number") \
V(nan_string, "NaN") \
V(RegExp_string, "RegExp") \
V(source_string, "source") \
V(global_string, "global") \
V(ignore_case_string, "ignoreCase") \
V(multiline_string, "multiline") \
V(input_string, "input") \
V(index_string, "index") \
V(last_index_string, "lastIndex") \
V(object_string, "object") \
V(prototype_string, "prototype") \
V(string_string, "string") \
V(String_string, "String") \
V(Date_string, "Date") \
V(this_string, "this") \
V(to_string_string, "toString") \
V(char_at_string, "CharAt") \
V(undefined_string, "undefined") \
V(value_of_string, "valueOf") \
V(stack_string, "stack") \
V(InitializeVarGlobal_string, "InitializeVarGlobal") \
V(InitializeConstGlobal_string, "InitializeConstGlobal") \
V(KeyedLoadElementMonomorphic_string, \
"KeyedLoadElementMonomorphic") \
V(KeyedStoreElementMonomorphic_string, \
"KeyedStoreElementMonomorphic") \
V(stack_overflow_string, "kStackOverflowBoilerplate") \
V(illegal_access_string, "illegal access") \
V(out_of_memory_string, "out-of-memory") \
V(illegal_execution_state_string, "illegal execution state") \
V(get_string, "get") \
V(set_string, "set") \
V(map_field_string, "%map") \
V(elements_field_string, "%elements") \
V(length_field_string, "%length") \
V(function_class_string, "Function") \
V(illegal_argument_string, "illegal argument") \
V(MakeReferenceError_string, "MakeReferenceError") \
V(MakeSyntaxError_string, "MakeSyntaxError") \
V(MakeTypeError_string, "MakeTypeError") \
V(invalid_lhs_in_assignment_string, "invalid_lhs_in_assignment") \
V(invalid_lhs_in_for_in_string, "invalid_lhs_in_for_in") \
V(invalid_lhs_in_postfix_op_string, "invalid_lhs_in_postfix_op") \
V(invalid_lhs_in_prefix_op_string, "invalid_lhs_in_prefix_op") \
V(illegal_return_string, "illegal_return") \
V(illegal_break_string, "illegal_break") \
V(illegal_continue_string, "illegal_continue") \
V(unknown_label_string, "unknown_label") \
V(redeclaration_string, "redeclaration") \
V(failure_string, "<failure>") \
V(space_string, " ") \
V(exec_string, "exec") \
V(zero_string, "0") \
V(global_eval_string, "GlobalEval") \
V(identity_hash_string, "v8::IdentityHash") \
V(closure_string, "(closure)") \
V(use_strict_string, "use strict") \
V(dot_string, ".") \
V(anonymous_function_string, "(anonymous function)") \
V(compare_ic_string, "==") \
V(strict_compare_ic_string, "===") \
V(infinity_string, "Infinity") \
V(minus_infinity_string, "-Infinity") \
V(hidden_stack_trace_string, "v8::hidden_stack_trace") \
V(query_colon_string, "(?:)")
objects.h中定义如下的宏：
// A struct is a simple object a set of object-valued fields. Including an
// object type in this causes the compiler to generate most of the boilerplate
// code for the class including allocation and garbage collection routines,
// casts and predicates. All you need to define is the class, methods and
// object verification routines. Easy, no?
//
// Note that for subtle reasons related to the ordering or numerical values of
// type tags, elements in this list have to be added to the INSTANCE_TYPE_LIST
// manually.
#define STRUCT_LIST_ALL(V) \
V(DECLARED_ACCESSOR_DESCRIPTOR, \
DeclaredAccessorDescriptor, \
declared_accessor_descriptor) \
V(DECLARED_ACCESSOR_INFO, DeclaredAccessorInfo, declared_accessor_info) \
V(EXECUTABLE_ACCESSOR_INFO, ExecutableAccessorInfo, executable_accessor_info)\
V(ACCESSOR_PAIR, AccessorPair, accessor_pair) \
V(ACCESS_CHECK_INFO, AccessCheckInfo, access_check_info) \
V(INTERCEPTOR_INFO, InterceptorInfo, interceptor_info) \
V(CALL_HANDLER_INFO, CallHandlerInfo, call_handler_info) \
V(FUNCTION_TEMPLATE_INFO, FunctionTemplateInfo, function_template_info) \
V(OBJECT_TEMPLATE_INFO, ObjectTemplateInfo, object_template_info) \
V(SIGNATURE_INFO, SignatureInfo, signature_info) \
V(TYPE_SWITCH_INFO, TypeSwitchInfo, type_switch_info) \
V(SCRIPT, Script, script) \
V(ALLOCATION_SITE_INFO, AllocationSiteInfo, allocation_site_info) \
V(CODE_CACHE, CodeCache, code_cache) \
V(POLYMORPHIC_CODE_CACHE, PolymorphicCodeCache, polymorphic_code_cache) \
V(TYPE_FEEDBACK_INFO, TypeFeedbackInfo, type_feedback_info) \
V(ALIASED_ARGUMENTS_ENTRY, AliasedArgumentsEntry, aliased_arguments_entry)
#ifdef ENABLE_DEBUGGER_SUPPORT
#define STRUCT_LIST_DEBUGGER(V) \
V(DEBUG_INFO, DebugInfo, debug_info) \
V(BREAK_POINT_INFO, BreakPointInfo, break_point_info)
#else
#define STRUCT_LIST_DEBUGGER(V)
#endif
#define STRUCT_LIST(V) \
STRUCT_LIST_ALL(V) \
STRUCT_LIST_DEBUGGER(V)
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