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
38namespace v8 {
39namespace internal {
40
41class 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