src/objects.h - Issue 1033653002: Move prototype metadata from internal properties to prototype maps

Unified Diff: src/objects.h

Issue 1033653002: Move prototype metadata from internal properties to prototype maps (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master

Patch Set: small fixes Created 5 years, 9 months ago

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Index: src/objects.h

diff --git a/src/objects.h b/src/objects.h

index 5961dc060f82ac581ccda19073d2375e2dfe9b34..6f24312e9d376443d3ac8ff350ec0c046c2a76b1 100644

--- a/src/objects.h

+++ b/src/objects.h

@@ -144,6 +144,7 @@

// - DebugInfo

// - BreakPointInfo

// - CodeCache

+// - PrototypeInfo

// - WeakCell

// Formats of Object*:

@@ -420,6 +421,7 @@ const int kStubMinorKeyBits = kSmiValueSize - kStubMajorKeyBits - 1;

V(TYPE_FEEDBACK_INFO_TYPE) \

V(ALIASED_ARGUMENTS_ENTRY_TYPE) \

V(BOX_TYPE) \

+ V(PROTOTYPE_INFO_TYPE) \

V(FIXED_ARRAY_TYPE) \

V(FIXED_DOUBLE_ARRAY_TYPE) \

@@ -517,25 +519,27 @@ const int kStubMinorKeyBits = kSmiValueSize - kStubMajorKeyBits - 1;

// 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(V) \

- V(BOX, Box, box) \

- 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(TYPE_SWITCH_INFO, TypeSwitchInfo, type_switch_info) \

- V(SCRIPT, Script, script) \

- V(ALLOCATION_SITE, AllocationSite, allocation_site) \

- V(ALLOCATION_MEMENTO, AllocationMemento, allocation_memento) \

- 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) \

- V(DEBUG_INFO, DebugInfo, debug_info) \

- V(BREAK_POINT_INFO, BreakPointInfo, break_point_info)

+#define STRUCT_LIST(V) \

+ V(BOX, Box, box) \

+ 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(TYPE_SWITCH_INFO, TypeSwitchInfo, type_switch_info) \

+ V(SCRIPT, Script, script) \

+ V(ALLOCATION_SITE, AllocationSite, allocation_site) \

+ V(ALLOCATION_MEMENTO, AllocationMemento, allocation_memento) \

+ 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) \

+ V(DEBUG_INFO, DebugInfo, debug_info) \

+ V(BREAK_POINT_INFO, BreakPointInfo, break_point_info) \

+ V(PROTOTYPE_INFO, PrototypeInfo, prototype_info)

// We use the full 8 bits of the instance_type field to encode heap object

// instance types. The high-order bit (bit 7) is set if the object is not a

@@ -718,6 +722,7 @@ enum InstanceType {

SHARED_FUNCTION_INFO_TYPE,

WEAK_CELL_TYPE,

PROPERTY_CELL_TYPE,

+ PROTOTYPE_INFO_TYPE,

// All the following types are subtypes of JSReceiver, which corresponds to

// objects in the JS sense. The first and the last type in this range are

@@ -2049,7 +2054,11 @@ class JSObject: public JSReceiver {

static void TransitionElementsKind(Handle<JSObject> object,

ElementsKind to_kind);

- static void MigrateToMap(Handle<JSObject> object, Handle<Map> new_map);

+ // Always use this to migrate an object to a new map.

+ // |expected_additional_properties| is only used for fast-to-slow transitions

+ // and ignored otherwise.

+ static void MigrateToMap(Handle<JSObject> object, Handle<Map> new_map,

+ int expected_additional_properties = 0);

// Convert the object to use the canonical dictionary

// representation. If the object is expected to have additional properties

@@ -2603,6 +2612,8 @@ class WeakFixedArray : public FixedArray {

inline Object* Get(int index) const;

inline int Length() const;

+ static Object* Empty() { return Smi::FromInt(0); }

DECLARE_CAST(WeakFixedArray)

private:

@@ -5796,15 +5807,15 @@ class Map: public HeapObject {

inline void set_unused_property_fields(int value);

// Bit field.

- inline byte bit_field();

+ inline byte bit_field() const;

inline void set_bit_field(byte value);

// Bit field 2.

- inline byte bit_field2();

+ inline byte bit_field2() const;

inline void set_bit_field2(byte value);

// Bit field 3.

- inline uint32_t bit_field3();

+ inline uint32_t bit_field3() const;

inline void set_bit_field3(uint32_t bits);

class EnumLengthBits: public BitField<int,

@@ -5899,7 +5910,7 @@ class Map: public HeapObject {

inline void set_is_extensible(bool value);

inline bool is_extensible();

inline void set_is_prototype_map(bool value);

- inline bool is_prototype_map();

+ inline bool is_prototype_map() const;

inline void set_elements_kind(ElementsKind elements_kind) {

DCHECK(static_cast<int>(elements_kind) < kElementsKindCount);

@@ -5970,6 +5981,9 @@ class Map: public HeapObject {

// Don't call set_raw_transitions() directly to overwrite transitions, use

// the TransitionArray::ReplaceTransitions() wrapper instead!

DECL_ACCESSORS(raw_transitions, Object)

+ // [prototype_info]: Per-prototype metadata. Aliased with transitions

+ // (which prototype maps don't have).

+ DECL_ACCESSORS(prototype_info, Object)

Map* FindRootMap();

Map* FindFieldOwner(int descriptor);

@@ -6328,9 +6342,10 @@ class Map: public HeapObject {

// otherwise a transition array is used.

// For prototype maps, this slot is used to store a pointer to the prototype

// object using this map.

- static const int kTransitionsOffset =

+ static const int kTransitionsOrPrototypeInfoOffset =

kConstructorOrBackPointerOffset + kPointerSize;

- static const int kDescriptorsOffset = kTransitionsOffset + kPointerSize;

+ static const int kDescriptorsOffset =

+ kTransitionsOrPrototypeInfoOffset + kPointerSize;

#if V8_DOUBLE_FIELDS_UNBOXING

static const int kLayoutDecriptorOffset = kDescriptorsOffset + kPointerSize;

static const int kCodeCacheOffset = kLayoutDecriptorOffset + kPointerSize;

@@ -6535,6 +6550,33 @@ class Box : public Struct {

};

+// Container for metadata stored on each prototype map.

+class PrototypeInfo : public Struct {

+ public:

+ // [prototype_users]: WeakFixedArray containing maps using this prototype,

+ // or Smi(0) if uninitialized.

+ DECL_ACCESSORS(prototype_users, Object)

+ // [validity_cell]: Cell containing the validity bit for prototype chains

+ // going through this object, or Smi(0) if uninitialized.

+ DECL_ACCESSORS(validity_cell, Object)

+ DECLARE_CAST(PrototypeInfo)

+ // Dispatched behavior.

+ DECLARE_PRINTER(PrototypeInfo)

+ DECLARE_VERIFIER(PrototypeInfo)

+ static const int kPrototypeObjectOffset = HeapObject::kHeaderSize;

+ static const int kPrototypeUsersOffset =

+ kPrototypeObjectOffset + kPointerSize;

+ static const int kValidityCellOffset = kPrototypeUsersOffset + kPointerSize;

+ static const int kSize = kValidityCellOffset + kPointerSize;

+ private:

+ DISALLOW_IMPLICIT_CONSTRUCTORS(PrototypeInfo);

+};

// Script describes a script which has been added to the VM.

class Script: public Struct {

public:

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