[runtime] Cleanup Map class definition.

.. by using macros for defining field offsets.

Bug: v8:5799
Change-Id: Id76e81bedb8f348b2efaa1d553bebac0ff90b474
Reviewed-on: https://chromium-review.googlesource.com/768382Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49351}

src/base/bits.h

@@ -131,7 +131,8 @@ inline constexpr unsigned CountTrailingZeros64(uint64_t value) {
 
 // Returns true iff |value| is a power of 2.
 template <typename T,
-          typename = typename std::enable_if<std::is_integral<T>::value>::type>
+          typename = typename std::enable_if<std::is_integral<T>::value ||
+                                             std::is_enum<T>::value>::type>
 constexpr inline bool IsPowerOfTwo(T value) {
   return value > 0 && (value & (value - 1)) == 0;
 }

src/code-stub-assembler.cc

@@ -1372,7 +1372,6 @@ TNode<IntPtrT> CodeStubAssembler::LoadMapInobjectProperties(
     SloppyTNode<Map> map) {
   CSA_SLOW_ASSERT(this, IsMap(map));
   // See Map::GetInObjectProperties() for details.
-  STATIC_ASSERT(LAST_JS_OBJECT_TYPE == LAST_TYPE);
   CSA_ASSERT(this, IsJSObjectMap(map));
   return ChangeInt32ToIntPtr(LoadObjectField(
       map, Map::kInObjectPropertiesOrConstructorFunctionIndexOffset,
@@ -1383,9 +1382,7 @@ TNode<IntPtrT> CodeStubAssembler::LoadMapConstructorFunctionIndex(
     SloppyTNode<Map> map) {
   CSA_SLOW_ASSERT(this, IsMap(map));
   // See Map::GetConstructorFunctionIndex() for details.
-  STATIC_ASSERT(FIRST_PRIMITIVE_TYPE == FIRST_TYPE);
-  CSA_ASSERT(this, Int32LessThanOrEqual(LoadMapInstanceType(map),
-                                        Int32Constant(LAST_PRIMITIVE_TYPE)));
+  CSA_ASSERT(this, IsPrimitiveInstanceType(LoadMapInstanceType(map)));
   return ChangeInt32ToIntPtr(LoadObjectField(
       map, Map::kInObjectPropertiesOrConstructorFunctionIndexOffset,
       MachineType::Uint8()));

src/globals.h

@@ -148,6 +148,7 @@ const int kMinUInt16 = 0;
 const uint32_t kMaxUInt32 = 0xFFFFFFFFu;
 const int kMinUInt32 = 0;
 
+const int kUInt8Size = sizeof(uint8_t);
 const int kCharSize = sizeof(char);
 const int kShortSize = sizeof(short);  // NOLINT
 const int kIntSize = sizeof(int);

src/heap/objects-visiting-inl.h

@@ -31,7 +31,7 @@ template <typename ResultType, typename ConcreteVisitor>
 ResultType HeapVisitor<ResultType, ConcreteVisitor>::Visit(Map* map,
                                                            HeapObject* object) {
   ConcreteVisitor* visitor = static_cast<ConcreteVisitor*>(this);
-  switch (static_cast<VisitorId>(map->visitor_id())) {
+  switch (map->visitor_id()) {
 #define CASE(type)                   \
   case kVisit##type:                 \
     return visitor->Visit##type(map, \

src/heap/scavenger-inl.h

@@ -116,7 +116,7 @@ bool Scavenger::PromoteObject(Map* map, HeapObject** slot, HeapObject* object,
     }
     *slot = target;
 
-    if (!ContainsOnlyData(static_cast<VisitorId>(map->visitor_id()))) {
+    if (!ContainsOnlyData(map->visitor_id())) {
       promotion_list_.Push(ObjectAndSize(target, object_size));
     }
     promoted_size_ += object_size;
@@ -206,7 +206,7 @@ void Scavenger::EvacuateObject(HeapObject** slot, Map* map,
   int size = source->SizeFromMap(map);
   // Cannot use ::cast() below because that would add checks in debug mode
   // that require re-reading the map.
-  switch (static_cast<VisitorId>(map->visitor_id())) {
+  switch (map->visitor_id()) {
     case kVisitThinString:
       EvacuateThinString(map, slot, reinterpret_cast<ThinString*>(source),
                          size);

src/objects-inl.h

@@ -2968,9 +2968,11 @@ Handle<Object> Float64ArrayTraits::ToHandle(Isolate* isolate, double scalar) {
   return isolate->factory()->NewNumber(scalar);
 }
 
-int Map::visitor_id() const { return READ_BYTE_FIELD(this, kVisitorIdOffset); }
+VisitorId Map::visitor_id() const {
+  return static_cast<VisitorId>(READ_BYTE_FIELD(this, kVisitorIdOffset));
+}
 
-void Map::set_visitor_id(int id) {
+void Map::set_visitor_id(VisitorId id) {
   DCHECK_LE(0, id);
   DCHECK_LT(id, 256);
   WRITE_BYTE_FIELD(this, kVisitorIdOffset, static_cast<byte>(id));
@@ -3573,12 +3575,14 @@ void Map::set_prototype(Object* value, WriteBarrierMode mode) {
 }
 
 LayoutDescriptor* Map::layout_descriptor_gc_safe() const {
+  DCHECK(FLAG_unbox_double_fields);
   Object* layout_desc = RELAXED_READ_FIELD(this, kLayoutDescriptorOffset);
   return LayoutDescriptor::cast_gc_safe(layout_desc);
 }
 
 
 bool Map::HasFastPointerLayout() const {
+  DCHECK(FLAG_unbox_double_fields);
   Object* layout_desc = RELAXED_READ_FIELD(this, kLayoutDescriptorOffset);
   return LayoutDescriptor::IsFastPointerLayout(layout_desc);
 }
@@ -3595,7 +3599,7 @@ void Map::UpdateDescriptors(DescriptorArray* descriptors,
     // TODO(ishell): remove these checks from VERIFY_HEAP mode.
     if (FLAG_verify_heap) {
       CHECK(layout_descriptor()->IsConsistentWithMap(this));
-      CHECK(visitor_id() == Map::GetVisitorId(this));
+      CHECK_EQ(Map::GetVisitorId(this), visitor_id());
     }
 #else
     SLOW_DCHECK(layout_descriptor()->IsConsistentWithMap(this));
@@ -3627,7 +3631,8 @@ void Map::InitializeDescriptors(DescriptorArray* descriptors,
 
 
 ACCESSORS(Map, instance_descriptors, DescriptorArray, kDescriptorsOffset)
-ACCESSORS(Map, layout_descriptor, LayoutDescriptor, kLayoutDescriptorOffset)
+ACCESSORS_CHECKED(Map, layout_descriptor, LayoutDescriptor,
+                  kLayoutDescriptorOffset, FLAG_unbox_double_fields)
 
 void Map::set_bit_field3(uint32_t bits) {
   if (kInt32Size != kPointerSize) {

src/objects/map.h

@@ -151,7 +151,9 @@ typedef std::vector<Handle<Map>> MapHandles;
 // | TaggedPointer | [instance_descriptors]                      |
 // +*************************************************************+
 // ! TaggedPointer ! [layout_descriptors]                        !
-// !               ! Field is only present on 64 bit arch        !
+// !               ! Field is only present if compile-time flag  !
+// !               ! FLAG_unbox_double_fields is enabled         !
+// !               ! (basically on 64 bit architectures)         !
 // +*************************************************************+
 // | TaggedPointer | [dependent_code]                            |
 // +---------------+---------------------------------------------+
@@ -163,14 +165,13 @@ class Map : public HeapObject {
   // Instance size.
   // Size in bytes or kVariableSizeSentinel if instances do not have
   // a fixed size.
-  inline int instance_size() const;
-  inline void set_instance_size(int value);
+  DECL_INT_ACCESSORS(instance_size)
 
   // [inobject_properties_or_constructor_function_index]: Provides access
   // to the inobject properties in case of JSObject maps, or the constructor
   // function index in case of primitive maps.
-  inline int inobject_properties_or_constructor_function_index() const;
-  inline void set_inobject_properties_or_constructor_function_index(int value);
+  DECL_INT_ACCESSORS(inobject_properties_or_constructor_function_index)
+
   // Count of properties allocated in the object (JSObject only).
   inline int GetInObjectProperties() const;
   inline void SetInObjectProperties(int value);
@@ -206,8 +207,7 @@ class Map : public HeapObject {
   //     - there is no slack in the object.
   //     - the property array has value slack slots.
   // Note that this encoding requires that H = JSObject::kFieldsAdded.
-  inline int used_instance_size_in_words() const;
-  inline void set_used_instance_size_in_words(int value);
+  DECL_INT_ACCESSORS(used_instance_size_in_words)
   inline int UsedInstanceSize() const;
 
   inline int UnusedPropertyFields() const;
@@ -320,21 +320,18 @@ class Map : public HeapObject {
 
   // Tells whether the instance has a [[Construct]] internal method.
   // This property is implemented according to ES6, section 7.2.4.
-  inline void set_is_constructor(bool value);
-  inline bool is_constructor() const;
+  DECL_BOOLEAN_ACCESSORS(is_constructor)
 
   // Tells whether the instance with this map may have properties for
   // interesting symbols on it.
   // An "interesting symbol" is one for which Name::IsInterestingSymbol()
   // returns true, i.e. a well-known symbol like @@toStringTag.
-  inline void set_may_have_interesting_symbols(bool value);
-  inline bool may_have_interesting_symbols() const;
+  DECL_BOOLEAN_ACCESSORS(may_have_interesting_symbols)
 
   DECL_BOOLEAN_ACCESSORS(has_prototype_slot)
 
   // Tells whether the instance with this map has a hidden prototype.
-  inline void set_has_hidden_prototype(bool value);
-  inline bool has_hidden_prototype() const;
+  DECL_BOOLEAN_ACCESSORS(has_hidden_prototype)
 
   // Records and queries whether the instance has a named interceptor.
   inline void set_has_named_interceptor();
@@ -358,12 +355,9 @@ class Map : public HeapObject {
   inline void set_is_callable();
   inline bool is_callable() const;
 
-  inline void set_new_target_is_base(bool value);
-  inline bool new_target_is_base() const;
-  inline void set_is_extensible(bool value);
-  inline bool is_extensible() const;
-  inline void set_is_prototype_map(bool value);
-  inline bool is_prototype_map() const;
+  DECL_BOOLEAN_ACCESSORS(new_target_is_base)
+  DECL_BOOLEAN_ACCESSORS(is_extensible)
+  DECL_BOOLEAN_ACCESSORS(is_prototype_map)
   inline bool is_abandoned_prototype_map() const;
 
   inline void set_elements_kind(ElementsKind elements_kind);
@@ -571,16 +565,14 @@ class Map : public HeapObject {
   inline int EnumLength() const;
   inline void SetEnumLength(int length);
 
-  inline bool owns_descriptors() const;
-  inline void set_owns_descriptors(bool owns_descriptors);
+  DECL_BOOLEAN_ACCESSORS(owns_descriptors)
   inline void mark_unstable();
   inline bool is_stable() const;
   inline void set_migration_target(bool value);
   inline bool is_migration_target() const;
   inline void set_immutable_proto(bool value);
   inline bool is_immutable_proto() const;
-  inline void set_construction_counter(int value);
-  inline int construction_counter() const;
+  DECL_INT_ACCESSORS(construction_counter)
   inline void deprecate();
   inline bool is_deprecated() const;
   inline bool CanBeDeprecated() const;
@@ -725,8 +717,7 @@ class Map : public HeapObject {
   void DictionaryMapVerify();
 #endif
 
-  inline int visitor_id() const;
-  inline void set_visitor_id(int visitor_id);
+  DECL_PRIMITIVE_ACCESSORS(visitor_id, VisitorId)
 
   static Handle<Map> TransitionToPrototype(Handle<Map> map,
                                            Handle<Object> prototype);
@@ -736,46 +727,29 @@ class Map : public HeapObject {
   static const int kMaxPreAllocatedPropertyFields = 255;
 
   // Layout description.
-  static const int kInstanceSizesOffset = HeapObject::kHeaderSize;
-  static const int kInstanceAttributesOffset = kInstanceSizesOffset + kIntSize;
-  static const int kBitField3Offset = kInstanceAttributesOffset + kIntSize;
-  static const int kPrototypeOffset = kBitField3Offset + kPointerSize;
-  static const int kConstructorOrBackPointerOffset =
-      kPrototypeOffset + kPointerSize;
-  // When there is only one transition, it is stored directly in this field;
-  // otherwise a transition array is used.
-  // For prototype maps, this slot is used to store this map's PrototypeInfo
-  // struct.
-  static const int kTransitionsOrPrototypeInfoOffset =
-      kConstructorOrBackPointerOffset + kPointerSize;
-  static const int kDescriptorsOffset =
-      kTransitionsOrPrototypeInfoOffset + kPointerSize;
-#if V8_DOUBLE_FIELDS_UNBOXING
-  static const int kLayoutDescriptorOffset = kDescriptorsOffset + kPointerSize;
-  static const int kDependentCodeOffset =
-      kLayoutDescriptorOffset + kPointerSize;
-#else
-  static const int kLayoutDescriptorOffset = 1;  // Must not be ever accessed.
-  static const int kDependentCodeOffset = kDescriptorsOffset + kPointerSize;
-#endif
-  static const int kWeakCellCacheOffset = kDependentCodeOffset + kPointerSize;
-  static const int kSize = kWeakCellCacheOffset + kPointerSize;
-
-  // Layout of pointer fields. Heap iteration code relies on them
-  // being continuously allocated.
-  static const int kPointerFieldsBeginOffset = Map::kPrototypeOffset;
-  static const int kPointerFieldsEndOffset = kSize;
-
-  // Byte offsets within kInstanceSizesOffset.
-  static const int kInstanceSizeOffset = kInstanceSizesOffset + 0;
-  static const int kInObjectPropertiesOrConstructorFunctionIndexByte = 1;
-  static const int kInObjectPropertiesOrConstructorFunctionIndexOffset =
-      kInstanceSizesOffset + kInObjectPropertiesOrConstructorFunctionIndexByte;
-  static const int kUsedInstanceSizeInWordsByte = 2;
-  static const int kUsedInstanceSizeInWordsOffset =
-      kInstanceSizesOffset + kUsedInstanceSizeInWordsByte;
-  static const int kVisitorIdByte = 3;
-  static const int kVisitorIdOffset = kInstanceSizesOffset + kVisitorIdByte;
+#define MAP_FIELDS(V)                                                       \
+  /* Raw data fields. */                                                    \
+  V(kInstanceSizeOffset, kUInt8Size)                                        \
+  V(kInObjectPropertiesOrConstructorFunctionIndexOffset, kUInt8Size)        \
+  V(kUsedInstanceSizeInWordsOffset, kUInt8Size)                             \
+  V(kVisitorIdOffset, kUInt8Size)                                           \
+  V(kInstanceAttributesOffset, kInt32Size)                                  \
+  V(kBitField3Offset, kPointerSize)                                         \
+  /* Pointer fields. */                                                     \
+  V(kPointerFieldsBeginOffset, 0)                                           \
+  V(kPrototypeOffset, kPointerSize)                                         \
+  V(kConstructorOrBackPointerOffset, kPointerSize)                          \
+  V(kTransitionsOrPrototypeInfoOffset, kPointerSize)                        \
+  V(kDescriptorsOffset, kPointerSize)                                       \
+  V(kLayoutDescriptorOffset, (FLAG_unbox_double_fields ? kPointerSize : 0)) \
+  V(kDependentCodeOffset, kPointerSize)                                     \
+  V(kWeakCellCacheOffset, kPointerSize)                                     \
+  V(kPointerFieldsEndOffset, 0)                                             \
+  /* Total size. */                                                         \
+  V(kSize, 0)
+
+  DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, MAP_FIELDS)
+#undef MAP_FIELDS
 
 // Byte offsets within kInstanceAttributesOffset attributes.
 #if V8_TARGET_LITTLE_ENDIAN
@@ -814,24 +788,6 @@ class Map : public HeapObject {
   class IsPrototypeMapBits : public BitField<bool, 2, 1> {};
   class ElementsKindBits : public BitField<ElementsKind, 3, 5> {};
 
-  // Derived values from bit field 2
-  static const int8_t kMaximumBitField2FastElementValue =
-      static_cast<int8_t>((PACKED_ELEMENTS + 1)
-                          << Map::ElementsKindBits::kShift) -
-      1;
-  static const int8_t kMaximumBitField2FastSmiElementValue =
-      static_cast<int8_t>((PACKED_SMI_ELEMENTS + 1)
-                          << Map::ElementsKindBits::kShift) -
-      1;
-  static const int8_t kMaximumBitField2FastHoleyElementValue =
-      static_cast<int8_t>((HOLEY_ELEMENTS + 1)
-                          << Map::ElementsKindBits::kShift) -
-      1;
-  static const int8_t kMaximumBitField2FastHoleySmiElementValue =
-      static_cast<int8_t>((HOLEY_SMI_ELEMENTS + 1)
-                          << Map::ElementsKindBits::kShift) -
-      1;
-
   typedef FixedBodyDescriptor<kPointerFieldsBeginOffset,
                               kPointerFieldsEndOffset, kSize>
       BodyDescriptor;

src/objects/object-macros-undef.h

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#undef DECL_PRIMITIVE_ACCESSORS
 #undef DECL_BOOLEAN_ACCESSORS
 #undef DECL_INT_ACCESSORS
 #undef DECL_ACCESSORS
@@ -17,6 +18,7 @@
 #undef RELAXED_SMI_ACCESSORS
 #undef BOOL_GETTER
 #undef BOOL_ACCESSORS
+#undef BIT_FIELD_ACCESSORS
 #undef TYPE_CHECKER
 #undef FIELD_ADDR
 #undef FIELD_ADDR_CONST

src/objects/object-macros.h

@@ -12,17 +12,15 @@
 // for fields that can be written to and read from multiple threads at the same
 // time. See comments in src/base/atomicops.h for the memory ordering sematics.
 
-#define DECL_BOOLEAN_ACCESSORS(name) \
-  inline bool name() const;          \
-  inline void set_##name(bool value);
+#define DECL_PRIMITIVE_ACCESSORS(name, type) \
+  inline type name() const;                  \
+  inline void set_##name(type value);
 
-#define DECL_INT_ACCESSORS(name) \
-  inline int name() const;       \
-  inline void set_##name(int value);
+#define DECL_BOOLEAN_ACCESSORS(name) DECL_PRIMITIVE_ACCESSORS(name, bool)
 
-#define DECL_INT32_ACCESSORS(name) \
-  inline int32_t name() const;     \
-  inline void set_##name(int32_t value);
+#define DECL_INT_ACCESSORS(name) DECL_PRIMITIVE_ACCESSORS(name, int)
+
+#define DECL_INT32_ACCESSORS(name) DECL_PRIMITIVE_ACCESSORS(name, int32_t)
 
 #define DECL_ACCESSORS(name, type)    \
   inline type* name() const;          \

src/profiler/heap-snapshot-generator.cc

@@ -1097,13 +1097,11 @@ void V8HeapExplorer::ExtractMapReferences(int entry, Map* map) {
                        Map::kDescriptorsOffset);
   SetInternalReference(map, entry, "prototype", map->prototype(),
                        Map::kPrototypeOffset);
-#if V8_DOUBLE_FIELDS_UNBOXING
   if (FLAG_unbox_double_fields) {
     SetInternalReference(map, entry, "layout_descriptor",
                          map->layout_descriptor(),
                          Map::kLayoutDescriptorOffset);
   }
-#endif
   Object* constructor_or_backpointer = map->constructor_or_backpointer();
   if (constructor_or_backpointer->IsMap()) {
     TagObject(constructor_or_backpointer, "(back pointer)");