| // Copyright 2012 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef V8_PROPERTY_DETAILS_H_ |
| #define V8_PROPERTY_DETAILS_H_ |
| |
| #include "include/v8.h" |
| #include "src/allocation.h" |
| #include "src/utils.h" |
| |
| // Ecma-262 3rd 8.6.1 |
| enum PropertyAttributes { |
| NONE = v8::None, |
| READ_ONLY = v8::ReadOnly, |
| DONT_ENUM = v8::DontEnum, |
| DONT_DELETE = v8::DontDelete, |
| |
| SEALED = DONT_DELETE, |
| FROZEN = SEALED | READ_ONLY, |
| |
| STRING = 8, // Used to filter symbols and string names |
| SYMBOLIC = 16, |
| PRIVATE_SYMBOL = 32, |
| |
| DONT_SHOW = DONT_ENUM | SYMBOLIC | PRIVATE_SYMBOL, |
| ABSENT = 64 // 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 { |
| |
| class Smi; |
| template<class> class TypeImpl; |
| struct ZoneTypeConfig; |
| typedef TypeImpl<ZoneTypeConfig> Type; |
| class TypeInfo; |
| |
| // Type of properties. |
| // Order of properties is significant. |
| // Must fit in the BitField PropertyDetails::TypeField. |
| // A copy of this is in mirror-debugger.js. |
| enum PropertyType { |
| // Only in slow mode. |
| NORMAL = 0, |
| // Only in fast mode. |
| FIELD = 1, |
| CONSTANT = 2, |
| CALLBACKS = 3 |
| }; |
| |
| |
| class Representation { |
| public: |
| enum Kind { |
| kNone, |
| kInteger8, |
| kUInteger8, |
| kInteger16, |
| kUInteger16, |
| kSmi, |
| kInteger32, |
| kDouble, |
| kHeapObject, |
| kTagged, |
| kExternal, |
| kNumRepresentations |
| }; |
| |
| Representation() : kind_(kNone) { } |
| |
| static Representation None() { return Representation(kNone); } |
| static Representation Tagged() { return Representation(kTagged); } |
| static Representation Integer8() { return Representation(kInteger8); } |
| static Representation UInteger8() { return Representation(kUInteger8); } |
| static Representation Integer16() { return Representation(kInteger16); } |
| static Representation UInteger16() { return Representation(kUInteger16); } |
| static Representation Smi() { return Representation(kSmi); } |
| static Representation Integer32() { return Representation(kInteger32); } |
| static Representation Double() { return Representation(kDouble); } |
| static Representation HeapObject() { return Representation(kHeapObject); } |
| static Representation External() { return Representation(kExternal); } |
| |
| static Representation FromKind(Kind kind) { return Representation(kind); } |
| |
| static Representation FromType(Type* type); |
| |
| bool Equals(const Representation& other) const { |
| return kind_ == other.kind_; |
| } |
| |
| bool IsCompatibleForLoad(const Representation& other) const { |
| return (IsDouble() && other.IsDouble()) || |
| (!IsDouble() && !other.IsDouble()); |
| } |
| |
| bool IsCompatibleForStore(const Representation& other) const { |
| return Equals(other); |
| } |
| |
| bool is_more_general_than(const Representation& other) const { |
| if (kind_ == kExternal && other.kind_ == kNone) return true; |
| if (kind_ == kExternal && other.kind_ == kExternal) return false; |
| if (kind_ == kNone && other.kind_ == kExternal) return false; |
| |
| DCHECK(kind_ != kExternal); |
| DCHECK(other.kind_ != kExternal); |
| if (IsHeapObject()) return other.IsNone(); |
| if (kind_ == kUInteger8 && other.kind_ == kInteger8) return false; |
| if (kind_ == kUInteger16 && other.kind_ == kInteger16) return false; |
| return kind_ > other.kind_; |
| } |
| |
| bool fits_into(const Representation& other) const { |
| return other.is_more_general_than(*this) || other.Equals(*this); |
| } |
| |
| Representation generalize(Representation other) { |
| if (other.fits_into(*this)) return *this; |
| if (other.is_more_general_than(*this)) return other; |
| return Representation::Tagged(); |
| } |
| |
| int size() const { |
| DCHECK(!IsNone()); |
| if (IsInteger8() || IsUInteger8()) { |
| return sizeof(uint8_t); |
| } |
| if (IsInteger16() || IsUInteger16()) { |
| return sizeof(uint16_t); |
| } |
| if (IsInteger32()) { |
| return sizeof(uint32_t); |
| } |
| return kPointerSize; |
| } |
| |
| Kind kind() const { return static_cast<Kind>(kind_); } |
| bool IsNone() const { return kind_ == kNone; } |
| bool IsInteger8() const { return kind_ == kInteger8; } |
| bool IsUInteger8() const { return kind_ == kUInteger8; } |
| bool IsInteger16() const { return kind_ == kInteger16; } |
| bool IsUInteger16() const { return kind_ == kUInteger16; } |
| bool IsTagged() const { return kind_ == kTagged; } |
| bool IsSmi() const { return kind_ == kSmi; } |
| bool IsSmiOrTagged() const { return IsSmi() || IsTagged(); } |
| bool IsInteger32() const { return kind_ == kInteger32; } |
| bool IsSmiOrInteger32() const { return IsSmi() || IsInteger32(); } |
| bool IsDouble() const { return kind_ == kDouble; } |
| bool IsHeapObject() const { return kind_ == kHeapObject; } |
| bool IsExternal() const { return kind_ == kExternal; } |
| bool IsSpecialization() const { |
| return IsInteger8() || IsUInteger8() || |
| IsInteger16() || IsUInteger16() || |
| IsSmi() || IsInteger32() || IsDouble(); |
| } |
| const char* Mnemonic() const; |
| |
| private: |
| explicit Representation(Kind k) : kind_(k) { } |
| |
| // Make sure kind fits in int8. |
| STATIC_ASSERT(kNumRepresentations <= (1 << kBitsPerByte)); |
| |
| int8_t kind_; |
| }; |
| |
| |
| static const int kDescriptorIndexBitCount = 10; |
| // The maximum number of descriptors we want in a descriptor array (should |
| // fit in a page). |
| static const int kMaxNumberOfDescriptors = |
| (1 << kDescriptorIndexBitCount) - 2; |
| static const int kInvalidEnumCacheSentinel = |
| (1 << kDescriptorIndexBitCount) - 1; |
| |
| |
| // 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) { |
| value_ = TypeField::encode(type) |
| | AttributesField::encode(attributes) |
| | DictionaryStorageField::encode(index); |
| |
| DCHECK(type == this->type()); |
| DCHECK(attributes == this->attributes()); |
| } |
| |
| PropertyDetails(PropertyAttributes attributes, |
| PropertyType type, |
| Representation representation, |
| int field_index = 0) { |
| value_ = TypeField::encode(type) |
| | AttributesField::encode(attributes) |
| | RepresentationField::encode(EncodeRepresentation(representation)) |
| | FieldIndexField::encode(field_index); |
| } |
| |
| int pointer() const { return DescriptorPointer::decode(value_); } |
| |
| PropertyDetails set_pointer(int i) { return PropertyDetails(value_, i); } |
| |
| PropertyDetails CopyWithRepresentation(Representation representation) const { |
| return PropertyDetails(value_, representation); |
| } |
| PropertyDetails CopyAddAttributes(PropertyAttributes new_attributes) { |
| new_attributes = |
| static_cast<PropertyAttributes>(attributes() | new_attributes); |
| return PropertyDetails(value_, new_attributes); |
| } |
| |
| // Conversion for storing details as Object*. |
| explicit inline PropertyDetails(Smi* smi); |
| inline Smi* AsSmi() const; |
| |
| static uint8_t EncodeRepresentation(Representation representation) { |
| return representation.kind(); |
| } |
| |
| static Representation DecodeRepresentation(uint32_t bits) { |
| return Representation::FromKind(static_cast<Representation::Kind>(bits)); |
| } |
| |
| PropertyType type() const { return TypeField::decode(value_); } |
| |
| PropertyAttributes attributes() const { |
| return AttributesField::decode(value_); |
| } |
| |
| int dictionary_index() const { |
| return DictionaryStorageField::decode(value_); |
| } |
| |
| Representation representation() const { |
| DCHECK(type() != NORMAL); |
| return DecodeRepresentation(RepresentationField::decode(value_)); |
| } |
| |
| int field_index() const { |
| return FieldIndexField::decode(value_); |
| } |
| |
| inline PropertyDetails AsDeleted() const; |
| |
| static bool IsValidIndex(int index) { |
| return DictionaryStorageField::is_valid(index); |
| } |
| |
| bool IsReadOnly() const { return (attributes() & READ_ONLY) != 0; } |
| bool IsConfigurable() const { return (attributes() & DONT_DELETE) == 0; } |
| bool IsDontEnum() const { return (attributes() & DONT_ENUM) != 0; } |
| bool IsDeleted() const { return DeletedField::decode(value_) != 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, 2> {}; |
| class AttributesField : public BitField<PropertyAttributes, 2, 3> {}; |
| |
| // Bit fields for normalized objects. |
| class DeletedField : public BitField<uint32_t, 5, 1> {}; |
| class DictionaryStorageField : public BitField<uint32_t, 6, 24> {}; |
| |
| // Bit fields for fast objects. |
| class RepresentationField : public BitField<uint32_t, 5, 4> {}; |
| class DescriptorPointer |
| : public BitField<uint32_t, 9, kDescriptorIndexBitCount> {}; // NOLINT |
| class FieldIndexField |
| : public BitField<uint32_t, 9 + kDescriptorIndexBitCount, |
| kDescriptorIndexBitCount> {}; // NOLINT |
| // All bits for fast objects must fix in a smi. |
| STATIC_ASSERT(9 + kDescriptorIndexBitCount + kDescriptorIndexBitCount <= 31); |
| |
| static const int kInitialIndex = 1; |
| |
| private: |
| PropertyDetails(int value, int pointer) { |
| value_ = DescriptorPointer::update(value, pointer); |
| } |
| PropertyDetails(int value, Representation representation) { |
| value_ = RepresentationField::update( |
| value, EncodeRepresentation(representation)); |
| } |
| PropertyDetails(int value, PropertyAttributes attributes) { |
| value_ = AttributesField::update(value, attributes); |
| } |
| |
| uint32_t value_; |
| }; |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_PROPERTY_DETAILS_H_ |