Home | History | Annotate | Download | only in src 
      1 // Copyright 2012 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 #ifndef V8_DATAFLOW_H_
     29 #define V8_DATAFLOW_H_
     30 
     31 #include "v8.h"
     32 
     33 #include "allocation.h"
     34 #include "ast.h"
     35 #include "compiler.h"
     36 #include "zone-inl.h"
     37 
     38 namespace v8 {
     39 namespace internal {
     40 
     41 class BitVector: public ZoneObject {
     42  public:
     43   // Iterator for the elements of this BitVector.
     44   class Iterator BASE_EMBEDDED {
     45    public:
     46     explicit Iterator(BitVector* target)
     47         : target_(target),
     48           current_index_(0),
     49           current_value_(target->data_[0]),
     50           current_(-1) {
     51       ASSERT(target->data_length_ > 0);
     52       Advance();
     53     }
     54     ~Iterator() { }
     55 
     56     bool Done() const { return current_index_ >= target_->data_length_; }
     57     void Advance();
     58 
     59     int Current() const {
     60       ASSERT(!Done());
     61       return current_;
     62     }
     63 
     64    private:
     65     uint32_t SkipZeroBytes(uint32_t val) {
     66       while ((val & 0xFF) == 0) {
     67         val >>= 8;
     68         current_ += 8;
     69       }
     70       return val;
     71     }
     72     uint32_t SkipZeroBits(uint32_t val) {
     73       while ((val & 0x1) == 0) {
     74         val >>= 1;
     75         current_++;
     76       }
     77       return val;
     78     }
     79 
     80     BitVector* target_;
     81     int current_index_;
     82     uint32_t current_value_;
     83     int current_;
     84 
     85     friend class BitVector;
     86   };
     87 
     88   BitVector(int length, Zone* zone)
     89       : length_(length),
     90         data_length_(SizeFor(length)),
     91         data_(zone->NewArray<uint32_t>(data_length_)) {
     92     ASSERT(length > 0);
     93     Clear();
     94   }
     95 
     96   BitVector(const BitVector& other, Zone* zone)
     97       : length_(other.length()),
     98         data_length_(SizeFor(length_)),
     99         data_(zone->NewArray<uint32_t>(data_length_)) {
    100     CopyFrom(other);
    101   }
    102 
    103   static int SizeFor(int length) {
    104     return 1 + ((length - 1) / 32);
    105   }
    106 
    107   BitVector& operator=(const BitVector& rhs) {
    108     if (this != &rhs) CopyFrom(rhs);
    109     return *this;
    110   }
    111 
    112   void CopyFrom(const BitVector& other) {
    113     ASSERT(other.length() <= length());
    114     for (int i = 0; i < other.data_length_; i++) {
    115       data_[i] = other.data_[i];
    116     }
    117     for (int i = other.data_length_; i < data_length_; i++) {
    118       data_[i] = 0;
    119     }
    120   }
    121 
    122   bool Contains(int i) const {
    123     ASSERT(i >= 0 && i < length());
    124     uint32_t block = data_[i / 32];
    125     return (block & (1U << (i % 32))) != 0;
    126   }
    127 
    128   void Add(int i) {
    129     ASSERT(i >= 0 && i < length());
    130     data_[i / 32] |= (1U << (i % 32));
    131   }
    132 
    133   void Remove(int i) {
    134     ASSERT(i >= 0 && i < length());
    135     data_[i / 32] &= ~(1U << (i % 32));
    136   }
    137 
    138   void Union(const BitVector& other) {
    139     ASSERT(other.length() == length());
    140     for (int i = 0; i < data_length_; i++) {
    141       data_[i] |= other.data_[i];
    142     }
    143   }
    144 
    145   bool UnionIsChanged(const BitVector& other) {
    146     ASSERT(other.length() == length());
    147     bool changed = false;
    148     for (int i = 0; i < data_length_; i++) {
    149       uint32_t old_data = data_[i];
    150       data_[i] |= other.data_[i];
    151       if (data_[i] != old_data) changed = true;
    152     }
    153     return changed;
    154   }
    155 
    156   void Intersect(const BitVector& other) {
    157     ASSERT(other.length() == length());
    158     for (int i = 0; i < data_length_; i++) {
    159       data_[i] &= other.data_[i];
    160     }
    161   }
    162 
    163   void Subtract(const BitVector& other) {
    164     ASSERT(other.length() == length());
    165     for (int i = 0; i < data_length_; i++) {
    166       data_[i] &= ~other.data_[i];
    167     }
    168   }
    169 
    170   void Clear() {
    171     for (int i = 0; i < data_length_; i++) {
    172       data_[i] = 0;
    173     }
    174   }
    175 
    176   bool IsEmpty() const {
    177     for (int i = 0; i < data_length_; i++) {
    178       if (data_[i] != 0) return false;
    179     }
    180     return true;
    181   }
    182 
    183   bool Equals(const BitVector& other) {
    184     for (int i = 0; i < data_length_; i++) {
    185       if (data_[i] != other.data_[i]) return false;
    186     }
    187     return true;
    188   }
    189 
    190   int length() const { return length_; }
    191 
    192 #ifdef DEBUG
    193   void Print();
    194 #endif
    195 
    196  private:
    197   int length_;
    198   int data_length_;
    199   uint32_t* data_;
    200 };
    201 
    202 } }  // namespace v8::internal
    203 
    204 
    205 #endif  // V8_DATAFLOW_H_
    206