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_DATAFLOW_H_ 6 #define V8_DATAFLOW_H_ 7 8 #include "src/allocation.h" 9 #include "src/zone/zone.h" 10 11 namespace v8 { 12 namespace internal { 13 14 class BitVector : public ZoneObject { 15 public: 16 // Iterator for the elements of this BitVector. 17 class Iterator BASE_EMBEDDED { 18 public: 19 explicit Iterator(BitVector* target) 20 : target_(target), 21 current_index_(0), 22 current_value_(target->data_[0]), 23 current_(-1) { 24 DCHECK(target->data_length_ > 0); 25 Advance(); 26 } 27 ~Iterator() {} 28 29 bool Done() const { return current_index_ >= target_->data_length_; } 30 void Advance(); 31 32 int Current() const { 33 DCHECK(!Done()); 34 return current_; 35 } 36 37 private: 38 uintptr_t SkipZeroBytes(uintptr_t val) { 39 while ((val & 0xFF) == 0) { 40 val >>= 8; 41 current_ += 8; 42 } 43 return val; 44 } 45 uintptr_t SkipZeroBits(uintptr_t val) { 46 while ((val & 0x1) == 0) { 47 val >>= 1; 48 current_++; 49 } 50 return val; 51 } 52 53 BitVector* target_; 54 int current_index_; 55 uintptr_t current_value_; 56 int current_; 57 58 friend class BitVector; 59 }; 60 61 static const int kDataBits = kPointerSize * 8; 62 static const int kDataBitShift = kPointerSize == 8 ? 6 : 5; 63 static const uintptr_t kOne = 1; // This saves some static_casts. 64 65 BitVector(int length, Zone* zone) 66 : length_(length), 67 data_length_(SizeFor(length)), 68 data_(zone->NewArray<uintptr_t>(data_length_)) { 69 DCHECK_LE(0, length); 70 Clear(); 71 } 72 73 BitVector(const BitVector& other, Zone* zone) 74 : length_(other.length()), 75 data_length_(SizeFor(length_)), 76 data_(zone->NewArray<uintptr_t>(data_length_)) { 77 CopyFrom(other); 78 } 79 80 static int SizeFor(int length) { 81 if (length == 0) return 1; 82 return 1 + ((length - 1) / kDataBits); 83 } 84 85 void CopyFrom(const BitVector& other) { 86 DCHECK(other.length() <= length()); 87 for (int i = 0; i < other.data_length_; i++) { 88 data_[i] = other.data_[i]; 89 } 90 for (int i = other.data_length_; i < data_length_; i++) { 91 data_[i] = 0; 92 } 93 } 94 95 bool Contains(int i) const { 96 DCHECK(i >= 0 && i < length()); 97 uintptr_t block = data_[i / kDataBits]; 98 return (block & (kOne << (i % kDataBits))) != 0; 99 } 100 101 void Add(int i) { 102 DCHECK(i >= 0 && i < length()); 103 data_[i / kDataBits] |= (kOne << (i % kDataBits)); 104 } 105 106 void AddAll() { memset(data_, -1, sizeof(uintptr_t) * data_length_); } 107 108 void Remove(int i) { 109 DCHECK(i >= 0 && i < length()); 110 data_[i / kDataBits] &= ~(kOne << (i % kDataBits)); 111 } 112 113 void Union(const BitVector& other) { 114 DCHECK(other.length() == length()); 115 for (int i = 0; i < data_length_; i++) { 116 data_[i] |= other.data_[i]; 117 } 118 } 119 120 bool UnionIsChanged(const BitVector& other) { 121 DCHECK(other.length() == length()); 122 bool changed = false; 123 for (int i = 0; i < data_length_; i++) { 124 uintptr_t old_data = data_[i]; 125 data_[i] |= other.data_[i]; 126 if (data_[i] != old_data) changed = true; 127 } 128 return changed; 129 } 130 131 void Intersect(const BitVector& other) { 132 DCHECK(other.length() == length()); 133 for (int i = 0; i < data_length_; i++) { 134 data_[i] &= other.data_[i]; 135 } 136 } 137 138 bool IntersectIsChanged(const BitVector& other) { 139 DCHECK(other.length() == length()); 140 bool changed = false; 141 for (int i = 0; i < data_length_; i++) { 142 uintptr_t old_data = data_[i]; 143 data_[i] &= other.data_[i]; 144 if (data_[i] != old_data) changed = true; 145 } 146 return changed; 147 } 148 149 void Subtract(const BitVector& other) { 150 DCHECK(other.length() == length()); 151 for (int i = 0; i < data_length_; i++) { 152 data_[i] &= ~other.data_[i]; 153 } 154 } 155 156 void Clear() { 157 for (int i = 0; i < data_length_; i++) { 158 data_[i] = 0; 159 } 160 } 161 162 bool IsEmpty() const { 163 for (int i = 0; i < data_length_; i++) { 164 if (data_[i] != 0) return false; 165 } 166 return true; 167 } 168 169 bool Equals(const BitVector& other) const { 170 for (int i = 0; i < data_length_; i++) { 171 if (data_[i] != other.data_[i]) return false; 172 } 173 return true; 174 } 175 176 int Count() const; 177 178 int length() const { return length_; } 179 180 #ifdef DEBUG 181 void Print(); 182 #endif 183 184 private: 185 const int length_; 186 const int data_length_; 187 uintptr_t* const data_; 188 189 DISALLOW_COPY_AND_ASSIGN(BitVector); 190 }; 191 192 193 class GrowableBitVector BASE_EMBEDDED { 194 public: 195 class Iterator BASE_EMBEDDED { 196 public: 197 Iterator(const GrowableBitVector* target, Zone* zone) 198 : it_(target->bits_ == NULL ? new (zone) BitVector(1, zone) 199 : target->bits_) {} 200 bool Done() const { return it_.Done(); } 201 void Advance() { it_.Advance(); } 202 int Current() const { return it_.Current(); } 203 204 private: 205 BitVector::Iterator it_; 206 }; 207 208 GrowableBitVector() : bits_(NULL) {} 209 GrowableBitVector(int length, Zone* zone) 210 : bits_(new (zone) BitVector(length, zone)) {} 211 212 bool Contains(int value) const { 213 if (!InBitsRange(value)) return false; 214 return bits_->Contains(value); 215 } 216 217 void Add(int value, Zone* zone) { 218 EnsureCapacity(value, zone); 219 bits_->Add(value); 220 } 221 222 void Union(const GrowableBitVector& other, Zone* zone) { 223 for (Iterator it(&other, zone); !it.Done(); it.Advance()) { 224 Add(it.Current(), zone); 225 } 226 } 227 228 void Clear() { 229 if (bits_ != NULL) bits_->Clear(); 230 } 231 232 private: 233 static const int kInitialLength = 1024; 234 235 bool InBitsRange(int value) const { 236 return bits_ != NULL && bits_->length() > value; 237 } 238 239 void EnsureCapacity(int value, Zone* zone) { 240 if (InBitsRange(value)) return; 241 int new_length = bits_ == NULL ? kInitialLength : bits_->length(); 242 while (new_length <= value) new_length *= 2; 243 BitVector* new_bits = new (zone) BitVector(new_length, zone); 244 if (bits_ != NULL) new_bits->CopyFrom(*bits_); 245 bits_ = new_bits; 246 } 247 248 BitVector* bits_; 249 }; 250 251 } // namespace internal 252 } // namespace v8 253 254 #endif // V8_DATAFLOW_H_ 255
