src/transitions-inl.h

   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_TRANSITIONS_INL_H_
   6 #define V8_TRANSITIONS_INL_H_
   7
   8 #include "src/transitions.h"
   9
  10 namespace v8 {
  11 namespace internal {
  12
  13
  14 #define FIELD_ADDR(p, offset) \
  15   (reinterpret_cast<byte*>(p) + offset - kHeapObjectTag)
  16
  17 #define WRITE_FIELD(p, offset, value) \
  18   (*reinterpret_cast<Object**>(FIELD_ADDR(p, offset)) = value)
  19
  20 #define CONDITIONAL_WRITE_BARRIER(heap, object, offset, value, mode)    \
  21   if (mode == UPDATE_WRITE_BARRIER) {                                   \
  22     heap->incremental_marking()->RecordWrite(                           \
  23       object, HeapObject::RawField(object, offset), value);             \
  24     if (heap->InNewSpace(value)) {                                      \
  25       heap->RecordWrite(object->address(), offset);                     \
  26     }                                                                   \
  27   }
  28
  29
  30 TransitionArray* TransitionArray::cast(Object* object) {
  31   DCHECK(object->IsTransitionArray());
  32   return reinterpret_cast<TransitionArray*>(object);
  33 }
  34
  35
  36 bool TransitionArray::HasElementsTransition() {
  37   return SearchSpecial(GetHeap()->elements_transition_symbol()) != kNotFound;
  38 }
  39
  40
  41 Object* TransitionArray::back_pointer_storage() {
  42   return get(kBackPointerStorageIndex);
  43 }
  44
  45
  46 void TransitionArray::set_back_pointer_storage(Object* back_pointer,
  47                                                WriteBarrierMode mode) {
  48   Heap* heap = GetHeap();
  49   WRITE_FIELD(this, kBackPointerStorageOffset, back_pointer);
  50   CONDITIONAL_WRITE_BARRIER(
  51       heap, this, kBackPointerStorageOffset, back_pointer, mode);
  52 }
  53
  54
  55 bool TransitionArray::HasPrototypeTransitions() {
  56   return IsFullTransitionArray() &&
  57       get(kPrototypeTransitionsIndex) != Smi::FromInt(0);
  58 }
  59
  60
  61 FixedArray* TransitionArray::GetPrototypeTransitions() {
  62   DCHECK(IsFullTransitionArray());
  63   Object* prototype_transitions = get(kPrototypeTransitionsIndex);
  64   return FixedArray::cast(prototype_transitions);
  65 }
  66
  67
  68 void TransitionArray::SetPrototypeTransitions(FixedArray* transitions,
  69                                               WriteBarrierMode mode) {
  70   DCHECK(IsFullTransitionArray());
  71   DCHECK(transitions->IsFixedArray());
  72   Heap* heap = GetHeap();
  73   WRITE_FIELD(this, kPrototypeTransitionsOffset, transitions);
  74   CONDITIONAL_WRITE_BARRIER(
  75       heap, this, kPrototypeTransitionsOffset, transitions, mode);
  76 }
  77
  78
  79 Object** TransitionArray::GetPrototypeTransitionsSlot() {
  80   return HeapObject::RawField(reinterpret_cast<HeapObject*>(this),
  81                               kPrototypeTransitionsOffset);
  82 }
  83
  84
  85 Object** TransitionArray::GetKeySlot(int transition_number) {
  86   DCHECK(!IsSimpleTransition());
  87   DCHECK(transition_number < number_of_transitions());
  88   return RawFieldOfElementAt(ToKeyIndex(transition_number));
  89 }
  90
  91
  92 Name* TransitionArray::GetKey(int transition_number) {
  93   if (IsSimpleTransition()) {
  94     Map* target = GetTarget(kSimpleTransitionIndex);
  95     int descriptor = target->LastAdded();
  96     Name* key = target->instance_descriptors()->GetKey(descriptor);
  97     return key;
  98   }
  99   DCHECK(transition_number < number_of_transitions());
 100   return Name::cast(get(ToKeyIndex(transition_number)));
 101 }
 102
 103
 104 void TransitionArray::SetKey(int transition_number, Name* key) {
 105   DCHECK(!IsSimpleTransition());
 106   DCHECK(transition_number < number_of_transitions());
 107   set(ToKeyIndex(transition_number), key);
 108 }
 109
 110
 111 Map* TransitionArray::GetTarget(int transition_number) {
 112   if (IsSimpleTransition()) {
 113     DCHECK(transition_number == kSimpleTransitionIndex);
 114     return Map::cast(get(kSimpleTransitionTarget));
 115   }
 116   DCHECK(transition_number < number_of_transitions());
 117   return Map::cast(get(ToTargetIndex(transition_number)));
 118 }
 119
 120
 121 void TransitionArray::SetTarget(int transition_number, Map* value) {
 122   if (IsSimpleTransition()) {
 123     DCHECK(transition_number == kSimpleTransitionIndex);
 124     return set(kSimpleTransitionTarget, value);
 125   }
 126   DCHECK(transition_number < number_of_transitions());
 127   set(ToTargetIndex(transition_number), value);
 128 }
 129
 130
 131 PropertyDetails TransitionArray::GetTargetDetails(int transition_number) {
 132   Map* map = GetTarget(transition_number);
 133   return map->GetLastDescriptorDetails();
 134 }
 135
 136
 137 Object* TransitionArray::GetTargetValue(int transition_number) {
 138   Map* map = GetTarget(transition_number);
 139   return map->instance_descriptors()->GetValue(map->LastAdded());
 140 }
 141
 142
 143 int TransitionArray::SearchName(Name* name, int* out_insertion_index) {
 144   if (IsSimpleTransition()) {
 145     Name* key = GetKey(kSimpleTransitionIndex);
 146     if (key->Equals(name)) return kSimpleTransitionIndex;
 147     if (out_insertion_index != NULL) {
 148       *out_insertion_index = key->Hash() > name->Hash() ? 0 : 1;
 149     }
 150     return kNotFound;
 151   }
 152   return internal::Search<ALL_ENTRIES>(this, name, 0, out_insertion_index);
 153 }
 154
 155
 156 #ifdef DEBUG
 157 bool TransitionArray::IsSpecialTransition(Name* name) {
 158   if (!name->IsSymbol()) return false;
 159   Heap* heap = name->GetHeap();
 160   return name == heap->frozen_symbol() ||
 161          name == heap->elements_transition_symbol() ||
 162          name == heap->observed_symbol();
 163 }
 164 #endif
 165
 166
 167 int TransitionArray::CompareKeys(Name* key1, uint32_t hash1,
 168                                  bool is_data_property1,
 169                                  PropertyAttributes attributes1, Name* key2,
 170                                  uint32_t hash2, bool is_data_property2,
 171                                  PropertyAttributes attributes2) {
 172   int cmp = CompareNames(key1, hash1, key2, hash2);
 173   if (cmp != 0) return cmp;
 174
 175   return CompareDetails(is_data_property1, attributes1, is_data_property2,
 176                         attributes2);
 177 }
 178
 179
 180 int TransitionArray::CompareNames(Name* key1, uint32_t hash1, Name* key2,
 181                                   uint32_t hash2) {
 182   if (key1 != key2) {
 183     // In case of hash collisions key1 is always "less" than key2.
 184     return hash1 <= hash2 ? -1 : 1;
 185   }
 186
 187   return 0;
 188 }
 189
 190
 191 int TransitionArray::CompareDetails(bool is_data_property1,
 192                                     PropertyAttributes attributes1,
 193                                     bool is_data_property2,
 194                                     PropertyAttributes attributes2) {
 195   if (is_data_property1 != is_data_property2) {
 196     return static_cast<int>(is_data_property1) <
 197                    static_cast<int>(is_data_property2)
 198                ? -1
 199                : 1;
 200   }
 201
 202   if (attributes1 != attributes2) {
 203     return static_cast<int>(attributes1) < static_cast<int>(attributes2) ? -1
 204                                                                          : 1;
 205   }
 206
 207   return 0;
 208 }
 209
 210
 211 PropertyDetails TransitionArray::GetTargetDetails(Name* name, Map* target) {
 212   DCHECK(!IsSpecialTransition(name));
 213   int descriptor = target->LastAdded();
 214   DescriptorArray* descriptors = target->instance_descriptors();
 215   // Transitions are allowed only for the last added property.
 216   DCHECK(descriptors->GetKey(descriptor)->Equals(name));
 217   return descriptors->GetDetails(descriptor);
 218 }
 219
 220
 221 void TransitionArray::NoIncrementalWriteBarrierSet(int transition_number,
 222                                                    Name* key,
 223                                                    Map* target) {
 224   FixedArray::NoIncrementalWriteBarrierSet(
 225       this, ToKeyIndex(transition_number), key);
 226   FixedArray::NoIncrementalWriteBarrierSet(
 227       this, ToTargetIndex(transition_number), target);
 228 }
 229
 230
 231 void TransitionArray::SetNumberOfTransitions(int number_of_transitions) {
 232   if (IsFullTransitionArray()) {
 233     DCHECK(number_of_transitions <= number_of_transitions_storage());
 234     WRITE_FIELD(this, kTransitionLengthOffset,
 235                 Smi::FromInt(number_of_transitions));
 236   }
 237 }
 238
 239
 240 #undef FIELD_ADDR
 241 #undef WRITE_FIELD
 242 #undef CONDITIONAL_WRITE_BARRIER
 243
 244
 245 } }  // namespace v8::internal
 246
 247 #endif  // V8_TRANSITIONS_INL_H_