LCOV - code coverage report
Current view: top level - src - property-details.h (source / functions) Hit Total Coverage
Test: app.info Lines: 66 74 89.2 %
Date: 2017-04-26 Functions: 11 14 78.6 %

          Line data    Source code
       1             : // Copyright 2012 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #ifndef V8_PROPERTY_DETAILS_H_
       6             : #define V8_PROPERTY_DETAILS_H_
       7             : 
       8             : #include "include/v8.h"
       9             : #include "src/allocation.h"
      10             : // TODO(ishell): remove once FLAG_track_constant_fields is removed.
      11             : #include "src/flags.h"
      12             : #include "src/utils.h"
      13             : 
      14             : namespace v8 {
      15             : namespace internal {
      16             : 
      17             : // ES6 6.1.7.1
      18             : enum PropertyAttributes {
      19             :   NONE = ::v8::None,
      20             :   READ_ONLY = ::v8::ReadOnly,
      21             :   DONT_ENUM = ::v8::DontEnum,
      22             :   DONT_DELETE = ::v8::DontDelete,
      23             : 
      24             :   ALL_ATTRIBUTES_MASK = READ_ONLY | DONT_ENUM | DONT_DELETE,
      25             : 
      26             :   SEALED = DONT_DELETE,
      27             :   FROZEN = SEALED | READ_ONLY,
      28             : 
      29             :   ABSENT = 64,  // Used in runtime to indicate a property is absent.
      30             :   // ABSENT can never be stored in or returned from a descriptor's attributes
      31             :   // bitfield.  It is only used as a return value meaning the attributes of
      32             :   // a non-existent property.
      33             : };
      34             : 
      35             : 
      36             : enum PropertyFilter {
      37             :   ALL_PROPERTIES = 0,
      38             :   ONLY_WRITABLE = 1,
      39             :   ONLY_ENUMERABLE = 2,
      40             :   ONLY_CONFIGURABLE = 4,
      41             :   SKIP_STRINGS = 8,
      42             :   SKIP_SYMBOLS = 16,
      43             :   ONLY_ALL_CAN_READ = 32,
      44             :   ENUMERABLE_STRINGS = ONLY_ENUMERABLE | SKIP_SYMBOLS,
      45             : };
      46             : // Enable fast comparisons of PropertyAttributes against PropertyFilters.
      47             : STATIC_ASSERT(ALL_PROPERTIES == static_cast<PropertyFilter>(NONE));
      48             : STATIC_ASSERT(ONLY_WRITABLE == static_cast<PropertyFilter>(READ_ONLY));
      49             : STATIC_ASSERT(ONLY_ENUMERABLE == static_cast<PropertyFilter>(DONT_ENUM));
      50             : STATIC_ASSERT(ONLY_CONFIGURABLE == static_cast<PropertyFilter>(DONT_DELETE));
      51             : STATIC_ASSERT(((SKIP_STRINGS | SKIP_SYMBOLS | ONLY_ALL_CAN_READ) &
      52             :                ALL_ATTRIBUTES_MASK) == 0);
      53             : STATIC_ASSERT(ALL_PROPERTIES ==
      54             :               static_cast<PropertyFilter>(v8::PropertyFilter::ALL_PROPERTIES));
      55             : STATIC_ASSERT(ONLY_WRITABLE ==
      56             :               static_cast<PropertyFilter>(v8::PropertyFilter::ONLY_WRITABLE));
      57             : STATIC_ASSERT(ONLY_ENUMERABLE ==
      58             :               static_cast<PropertyFilter>(v8::PropertyFilter::ONLY_ENUMERABLE));
      59             : STATIC_ASSERT(ONLY_CONFIGURABLE == static_cast<PropertyFilter>(
      60             :                                        v8::PropertyFilter::ONLY_CONFIGURABLE));
      61             : STATIC_ASSERT(SKIP_STRINGS ==
      62             :               static_cast<PropertyFilter>(v8::PropertyFilter::SKIP_STRINGS));
      63             : STATIC_ASSERT(SKIP_SYMBOLS ==
      64             :               static_cast<PropertyFilter>(v8::PropertyFilter::SKIP_SYMBOLS));
      65             : 
      66             : class Smi;
      67             : class TypeInfo;
      68             : 
      69             : // Order of kinds is significant.
      70             : // Must fit in the BitField PropertyDetails::KindField.
      71             : enum PropertyKind { kData = 0, kAccessor = 1 };
      72             : 
      73             : // Order of modes is significant.
      74             : // Must fit in the BitField PropertyDetails::LocationField.
      75             : enum PropertyLocation { kField = 0, kDescriptor = 1 };
      76             : 
      77             : // Order of modes is significant.
      78             : // Must fit in the BitField PropertyDetails::ConstnessField.
      79             : enum PropertyConstness { kMutable = 0, kConst = 1 };
      80             : 
      81             : // TODO(ishell): remove once constant field tracking is done.
      82             : const PropertyConstness kDefaultFieldConstness =
      83             :     FLAG_track_constant_fields ? kConst : kMutable;
      84             : 
      85             : class Representation {
      86             :  public:
      87             :   enum Kind {
      88             :     kNone,
      89             :     kInteger8,
      90             :     kUInteger8,
      91             :     kInteger16,
      92             :     kUInteger16,
      93             :     kSmi,
      94             :     kInteger32,
      95             :     kDouble,
      96             :     kHeapObject,
      97             :     kTagged,
      98             :     kExternal,
      99             :     kNumRepresentations
     100             :   };
     101             : 
     102    35455409 :   Representation() : kind_(kNone) { }
     103             : 
     104             :   static Representation None() { return Representation(kNone); }
     105             :   static Representation Tagged() { return Representation(kTagged); }
     106             :   static Representation Integer8() { return Representation(kInteger8); }
     107             :   static Representation UInteger8() { return Representation(kUInteger8); }
     108             :   static Representation Integer16() { return Representation(kInteger16); }
     109             :   static Representation UInteger16() { return Representation(kUInteger16); }
     110             :   static Representation Smi() { return Representation(kSmi); }
     111             :   static Representation Integer32() { return Representation(kInteger32); }
     112          14 :   static Representation Double() { return Representation(kDouble); }
     113             :   static Representation HeapObject() { return Representation(kHeapObject); }
     114             :   static Representation External() { return Representation(kExternal); }
     115             : 
     116             :   static Representation FromKind(Kind kind) { return Representation(kind); }
     117             : 
     118             :   bool Equals(const Representation& other) const {
     119    10320778 :     return kind_ == other.kind_;
     120             :   }
     121             : 
     122             :   bool IsCompatibleForLoad(const Representation& other) const {
     123        5846 :     return (IsDouble() && other.IsDouble()) ||
     124        5816 :         (!IsDouble() && !other.IsDouble());
     125             :   }
     126             : 
     127             :   bool IsCompatibleForStore(const Representation& other) const {
     128             :     return Equals(other);
     129             :   }
     130             : 
     131    20374867 :   bool is_more_general_than(const Representation& other) const {
     132    20374867 :     if (kind_ == kExternal && other.kind_ == kNone) return true;
     133    20367046 :     if (kind_ == kExternal && other.kind_ == kExternal) return false;
     134    20366926 :     if (kind_ == kNone && other.kind_ == kExternal) return false;
     135             : 
     136             :     DCHECK(kind_ != kExternal);
     137             :     DCHECK(other.kind_ != kExternal);
     138    22096758 :     if (IsHeapObject()) return other.IsNone();
     139    18621040 :     if (kind_ == kUInteger8 && other.kind_ == kInteger8) return false;
     140    18621020 :     if (kind_ == kUInteger16 && other.kind_ == kInteger16) return false;
     141    18621020 :     return kind_ > other.kind_;
     142             :   }
     143             : 
     144             :   bool fits_into(const Representation& other) const {
     145    22881211 :     return other.is_more_general_than(*this) || other.Equals(*this);
     146             :   }
     147             : 
     148    12934972 :   Representation generalize(Representation other) {
     149    12935118 :     if (other.fits_into(*this)) return *this;
     150     2521022 :     if (other.is_more_general_than(*this)) return other;
     151             :     return Representation::Tagged();
     152             :   }
     153             : 
     154           0 :   int size() const {
     155             :     DCHECK(!IsNone());
     156           0 :     if (IsInteger8() || IsUInteger8()) {
     157             :       return sizeof(uint8_t);
     158             :     }
     159           0 :     if (IsInteger16() || IsUInteger16()) {
     160             :       return sizeof(uint16_t);
     161             :     }
     162           0 :     if (IsInteger32()) {
     163             :       return sizeof(uint32_t);
     164             :     }
     165           0 :     return kPointerSize;
     166             :   }
     167             : 
     168    23746255 :   Kind kind() const { return static_cast<Kind>(kind_); }
     169     5294399 :   bool IsNone() const { return kind_ == kNone; }
     170     1026905 :   bool IsInteger8() const { return kind_ == kInteger8; }
     171             :   bool IsUInteger8() const { return kind_ == kUInteger8; }
     172             :   bool IsInteger16() const { return kind_ == kInteger16; }
     173             :   bool IsUInteger16() const { return kind_ == kUInteger16; }
     174     3799894 :   bool IsTagged() const { return kind_ == kTagged; }
     175    37104629 :   bool IsSmi() const { return kind_ == kSmi; }
     176    36353986 :   bool IsSmiOrTagged() const { return IsSmi() || IsTagged(); }
     177      153021 :   bool IsInteger32() const { return kind_ == kInteger32; }
     178    12336263 :   bool IsSmiOrInteger32() const { return IsSmi() || IsInteger32(); }
     179   433036424 :   bool IsDouble() const { return kind_ == kDouble; }
     180           0 :   bool IsHeapObject() const { return kind_ == kHeapObject; }
     181     1042809 :   bool IsExternal() const { return kind_ == kExternal; }
     182     1026905 :   bool IsSpecialization() const {
     183     1026905 :     return IsInteger8() || IsUInteger8() ||
     184     1026905 :       IsInteger16() || IsUInteger16() ||
     185     2051396 :       IsSmi() || IsInteger32() || IsDouble();
     186             :   }
     187             :   const char* Mnemonic() const;
     188             : 
     189             :  private:
     190   779509164 :   explicit Representation(Kind k) : kind_(k) { }
     191             : 
     192             :   // Make sure kind fits in int8.
     193             :   STATIC_ASSERT(kNumRepresentations <= (1 << kBitsPerByte));
     194             : 
     195             :   int8_t kind_;
     196             : };
     197             : 
     198             : 
     199             : static const int kDescriptorIndexBitCount = 10;
     200             : // The maximum number of descriptors we want in a descriptor array (should
     201             : // fit in a page).
     202             : static const int kMaxNumberOfDescriptors =
     203             :     (1 << kDescriptorIndexBitCount) - 2;
     204             : static const int kInvalidEnumCacheSentinel =
     205             :     (1 << kDescriptorIndexBitCount) - 1;
     206             : 
     207             : enum class PropertyCellType {
     208             :   // Meaningful when a property cell does not contain the hole.
     209             :   kUndefined,     // The PREMONOMORPHIC of property cells.
     210             :   kConstant,      // Cell has been assigned only once.
     211             :   kConstantType,  // Cell has been assigned only one type.
     212             :   kMutable,       // Cell will no longer be tracked as constant.
     213             : 
     214             :   // Meaningful when a property cell contains the hole.
     215             :   kUninitialized = kUndefined,  // Cell has never been initialized.
     216             :   kInvalidated = kConstant,     // Cell has been deleted, invalidated or never
     217             :                                 // existed.
     218             : 
     219             :   // For dictionaries not holding cells.
     220             :   kNoCell = kMutable,
     221             : };
     222             : 
     223             : enum class PropertyCellConstantType {
     224             :   kSmi,
     225             :   kStableMap,
     226             : };
     227             : 
     228             : 
     229             : // PropertyDetails captures type and attributes for a property.
     230             : // They are used both in property dictionaries and instance descriptors.
     231             : class PropertyDetails BASE_EMBEDDED {
     232             :  public:
     233             :   // Property details for dictionary mode properties/elements.
     234     2880625 :   PropertyDetails(PropertyKind kind, PropertyAttributes attributes, int index,
     235             :                   PropertyCellType cell_type) {
     236     9128063 :     value_ = KindField::encode(kind) | LocationField::encode(kField) |
     237    17546928 :              AttributesField::encode(attributes) |
     238    44245551 :              DictionaryStorageField::encode(index) |
     239    20126738 :              PropertyCellTypeField::encode(cell_type);
     240     2880625 :   }
     241             : 
     242             :   // Property details for fast mode properties.
     243             :   PropertyDetails(PropertyKind kind, PropertyAttributes attributes,
     244             :                   PropertyLocation location, PropertyConstness constness,
     245             :                   Representation representation, int field_index = 0) {
     246     1646126 :     value_ = KindField::encode(kind) | AttributesField::encode(attributes) |
     247    20023394 :              LocationField::encode(location) |
     248    22694971 :              ConstnessField::encode(constness) |
     249    41280002 :              RepresentationField::encode(EncodeRepresentation(representation)) |
     250    26282225 :              FieldIndexField::encode(field_index);
     251             :   }
     252             : 
     253         120 :   static PropertyDetails Empty(
     254             :       PropertyCellType cell_type = PropertyCellType::kNoCell) {
     255         120 :     return PropertyDetails(kData, NONE, 0, cell_type);
     256             :   }
     257             : 
     258  1110445765 :   int pointer() const { return DescriptorPointer::decode(value_); }
     259             : 
     260             :   PropertyDetails set_pointer(int i) const {
     261   204532584 :     return PropertyDetails(value_, i);
     262             :   }
     263             : 
     264             :   PropertyDetails set_cell_type(PropertyCellType type) const {
     265     8833395 :     PropertyDetails details = *this;
     266             :     details.value_ = PropertyCellTypeField::update(details.value_, type);
     267             :     return details;
     268             :   }
     269             : 
     270             :   PropertyDetails set_index(int index) const {
     271             :     PropertyDetails details = *this;
     272    28187644 :     details.value_ = DictionaryStorageField::update(details.value_, index);
     273             :     return details;
     274             :   }
     275             : 
     276             :   PropertyDetails CopyWithRepresentation(Representation representation) const {
     277             :     return PropertyDetails(value_, representation);
     278             :   }
     279             :   PropertyDetails CopyWithConstness(PropertyConstness constness) const {
     280             :     return PropertyDetails(value_, constness);
     281             :   }
     282             :   PropertyDetails CopyAddAttributes(PropertyAttributes new_attributes) const {
     283             :     new_attributes =
     284      104538 :         static_cast<PropertyAttributes>(attributes() | new_attributes);
     285             :     return PropertyDetails(value_, new_attributes);
     286             :   }
     287             : 
     288             :   // Conversion for storing details as Object*.
     289             :   explicit inline PropertyDetails(Smi* smi);
     290             :   inline Smi* AsSmi() const;
     291             : 
     292             :   static uint8_t EncodeRepresentation(Representation representation) {
     293             :     return representation.kind();
     294             :   }
     295             : 
     296             :   static Representation DecodeRepresentation(uint32_t bits) {
     297             :     return Representation::FromKind(static_cast<Representation::Kind>(bits));
     298             :   }
     299             : 
     300   236802541 :   PropertyKind kind() const { return KindField::decode(value_); }
     301   713315282 :   PropertyLocation location() const { return LocationField::decode(value_); }
     302           0 :   PropertyConstness constness() const { return ConstnessField::decode(value_); }
     303             : 
     304           0 :   PropertyAttributes attributes() const {
     305    24197407 :     return AttributesField::decode(value_);
     306             :   }
     307             : 
     308             :   int dictionary_index() const {
     309   264604053 :     return DictionaryStorageField::decode(value_);
     310             :   }
     311             : 
     312    62917623 :   Representation representation() const {
     313   332725208 :     return DecodeRepresentation(RepresentationField::decode(value_));
     314             :   }
     315             : 
     316   739121953 :   int field_index() const { return FieldIndexField::decode(value_); }
     317             : 
     318             :   inline int field_width_in_words() const;
     319             : 
     320             :   static bool IsValidIndex(int index) {
     321    30903219 :     return DictionaryStorageField::is_valid(index);
     322             :   }
     323             : 
     324    23271024 :   bool IsReadOnly() const { return (attributes() & READ_ONLY) != 0; }
     325    12946823 :   bool IsConfigurable() const { return (attributes() & DONT_DELETE) == 0; }
     326    23474762 :   bool IsDontEnum() const { return (attributes() & DONT_ENUM) != 0; }
     327             :   bool IsEnumerable() const { return !IsDontEnum(); }
     328             :   PropertyCellType cell_type() const {
     329    11918808 :     return PropertyCellTypeField::decode(value_);
     330             :   }
     331             : 
     332             :   // Bit fields in value_ (type, shift, size). Must be public so the
     333             :   // constants can be embedded in generated code.
     334             :   class KindField : public BitField<PropertyKind, 0, 1> {};
     335             :   class LocationField : public BitField<PropertyLocation, KindField::kNext, 1> {
     336             :   };
     337             :   class ConstnessField
     338             :       : public BitField<PropertyConstness, LocationField::kNext, 1> {};
     339             :   class AttributesField
     340             :       : public BitField<PropertyAttributes, ConstnessField::kNext, 3> {};
     341             :   static const int kAttributesReadOnlyMask =
     342             :       (READ_ONLY << AttributesField::kShift);
     343             :   static const int kAttributesDontDeleteMask =
     344             :       (DONT_DELETE << AttributesField::kShift);
     345             : 
     346             :   // Bit fields for normalized objects.
     347             :   class PropertyCellTypeField
     348             :       : public BitField<PropertyCellType, AttributesField::kNext, 2> {};
     349             :   class DictionaryStorageField
     350             :       : public BitField<uint32_t, PropertyCellTypeField::kNext, 23> {};
     351             : 
     352             :   // Bit fields for fast objects.
     353             :   class RepresentationField
     354             :       : public BitField<uint32_t, AttributesField::kNext, 4> {};
     355             :   class DescriptorPointer
     356             :       : public BitField<uint32_t, RepresentationField::kNext,
     357             :                         kDescriptorIndexBitCount> {};  // NOLINT
     358             :   class FieldIndexField : public BitField<uint32_t, DescriptorPointer::kNext,
     359             :                                           kDescriptorIndexBitCount> {
     360             :   };  // NOLINT
     361             : 
     362             :   // All bits for both fast and slow objects must fit in a smi.
     363             :   STATIC_ASSERT(DictionaryStorageField::kNext <= 31);
     364             :   STATIC_ASSERT(FieldIndexField::kNext <= 31);
     365             : 
     366             :   static const int kInitialIndex = 1;
     367             : 
     368             : #ifdef OBJECT_PRINT
     369             :   // For our gdb macros, we should perhaps change these in the future.
     370             :   void Print(bool dictionary_mode);
     371             : #endif
     372             : 
     373             :   enum PrintMode {
     374             :     kPrintAttributes = 1 << 0,
     375             :     kPrintFieldIndex = 1 << 1,
     376             :     kPrintRepresentation = 1 << 2,
     377             :     kPrintPointer = 1 << 3,
     378             : 
     379             :     kForProperties = kPrintFieldIndex,
     380             :     kForTransitions = kPrintAttributes,
     381             :     kPrintFull = -1,
     382             :   };
     383             :   void PrintAsSlowTo(std::ostream& out);
     384             :   void PrintAsFastTo(std::ostream& out, PrintMode mode = kPrintFull);
     385             : 
     386             :  private:
     387             :   PropertyDetails(int value, int pointer) {
     388   202034643 :     value_ = DescriptorPointer::update(value, pointer);
     389             :   }
     390             :   PropertyDetails(int value, Representation representation) {
     391             :     value_ = RepresentationField::update(
     392             :         value, EncodeRepresentation(representation));
     393             :   }
     394             :   PropertyDetails(int value, PropertyConstness constness) {
     395             :     value_ = ConstnessField::update(value, constness);
     396             :   }
     397             :   PropertyDetails(int value, PropertyAttributes attributes) {
     398             :     value_ = AttributesField::update(value, attributes);
     399             :   }
     400             : 
     401             :   uint32_t value_;
     402             : };
     403             : 
     404             : // kField location is more general than kDescriptor, kDescriptor generalizes
     405             : // only to itself.
     406             : inline bool IsGeneralizableTo(PropertyLocation a, PropertyLocation b) {
     407      501000 :   return b == kField || a == kDescriptor;
     408             : }
     409             : 
     410             : // kMutable constness is more general than kConst, kConst generalizes only to
     411             : // itself.
     412             : inline bool IsGeneralizableTo(PropertyConstness a, PropertyConstness b) {
     413    25342103 :   return b == kMutable || a == kConst;
     414             : }
     415             : 
     416             : inline PropertyConstness GeneralizeConstness(PropertyConstness a,
     417             :                                              PropertyConstness b) {
     418     1552777 :   return a == kMutable ? kMutable : b;
     419             : }
     420             : 
     421             : std::ostream& operator<<(std::ostream& os,
     422             :                          const PropertyAttributes& attributes);
     423             : }  // namespace internal
     424             : }  // namespace v8
     425             : 
     426             : #endif  // V8_PROPERTY_DETAILS_H_

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