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/v8.h"
9
10#include "src/allocation.h"
11#include "src/ast.h"
12#include "src/compiler.h"
13#include "src/zone-inl.h"
14
15namespace v8 {
16namespace internal {
17
18class BitVector: public ZoneObject {
19 public:
20  // Iterator for the elements of this BitVector.
21  class Iterator BASE_EMBEDDED {
22   public:
23    explicit Iterator(BitVector* target)
24        : target_(target),
25          current_index_(0),
26          current_value_(target->data_[0]),
27          current_(-1) {
28      DCHECK(target->data_length_ > 0);
29      Advance();
30    }
31    ~Iterator() { }
32
33    bool Done() const { return current_index_ >= target_->data_length_; }
34    void Advance();
35
36    int Current() const {
37      DCHECK(!Done());
38      return current_;
39    }
40
41   private:
42    uint32_t SkipZeroBytes(uint32_t val) {
43      while ((val & 0xFF) == 0) {
44        val >>= 8;
45        current_ += 8;
46      }
47      return val;
48    }
49    uint32_t SkipZeroBits(uint32_t val) {
50      while ((val & 0x1) == 0) {
51        val >>= 1;
52        current_++;
53      }
54      return val;
55    }
56
57    BitVector* target_;
58    int current_index_;
59    uint32_t current_value_;
60    int current_;
61
62    friend class BitVector;
63  };
64
65  BitVector(int length, Zone* zone)
66      : length_(length),
67        data_length_(SizeFor(length)),
68        data_(zone->NewArray<uint32_t>(data_length_)) {
69    DCHECK(length > 0);
70    Clear();
71  }
72
73  BitVector(const BitVector& other, Zone* zone)
74      : length_(other.length()),
75        data_length_(SizeFor(length_)),
76        data_(zone->NewArray<uint32_t>(data_length_)) {
77    CopyFrom(other);
78  }
79
80  static int SizeFor(int length) {
81    return 1 + ((length - 1) / 32);
82  }
83
84  BitVector& operator=(const BitVector& rhs) {
85    if (this != &rhs) CopyFrom(rhs);
86    return *this;
87  }
88
89  void CopyFrom(const BitVector& other) {
90    DCHECK(other.length() <= length());
91    for (int i = 0; i < other.data_length_; i++) {
92      data_[i] = other.data_[i];
93    }
94    for (int i = other.data_length_; i < data_length_; i++) {
95      data_[i] = 0;
96    }
97  }
98
99  bool Contains(int i) const {
100    DCHECK(i >= 0 && i < length());
101    uint32_t block = data_[i / 32];
102    return (block & (1U << (i % 32))) != 0;
103  }
104
105  void Add(int i) {
106    DCHECK(i >= 0 && i < length());
107    data_[i / 32] |= (1U << (i % 32));
108  }
109
110  void Remove(int i) {
111    DCHECK(i >= 0 && i < length());
112    data_[i / 32] &= ~(1U << (i % 32));
113  }
114
115  void Union(const BitVector& other) {
116    DCHECK(other.length() == length());
117    for (int i = 0; i < data_length_; i++) {
118      data_[i] |= other.data_[i];
119    }
120  }
121
122  bool UnionIsChanged(const BitVector& other) {
123    DCHECK(other.length() == length());
124    bool changed = false;
125    for (int i = 0; i < data_length_; i++) {
126      uint32_t old_data = data_[i];
127      data_[i] |= other.data_[i];
128      if (data_[i] != old_data) changed = true;
129    }
130    return changed;
131  }
132
133  void Intersect(const BitVector& other) {
134    DCHECK(other.length() == length());
135    for (int i = 0; i < data_length_; i++) {
136      data_[i] &= other.data_[i];
137    }
138  }
139
140  bool IntersectIsChanged(const BitVector& other) {
141    DCHECK(other.length() == length());
142    bool changed = false;
143    for (int i = 0; i < data_length_; i++) {
144      uint32_t old_data = data_[i];
145      data_[i] &= other.data_[i];
146      if (data_[i] != old_data) changed = true;
147    }
148    return changed;
149  }
150
151  void Subtract(const BitVector& other) {
152    DCHECK(other.length() == length());
153    for (int i = 0; i < data_length_; i++) {
154      data_[i] &= ~other.data_[i];
155    }
156  }
157
158  void Clear() {
159    for (int i = 0; i < data_length_; i++) {
160      data_[i] = 0;
161    }
162  }
163
164  bool IsEmpty() const {
165    for (int i = 0; i < data_length_; i++) {
166      if (data_[i] != 0) return false;
167    }
168    return true;
169  }
170
171  bool Equals(const BitVector& other) {
172    for (int i = 0; i < data_length_; i++) {
173      if (data_[i] != other.data_[i]) return false;
174    }
175    return true;
176  }
177
178  int Count() const;
179
180  int length() const { return length_; }
181
182#ifdef DEBUG
183  void Print();
184#endif
185
186 private:
187  int length_;
188  int data_length_;
189  uint32_t* data_;
190};
191
192
193class GrowableBitVector BASE_EMBEDDED {
194 public:
195  class Iterator BASE_EMBEDDED {
196   public:
197    Iterator(const GrowableBitVector* target, Zone* zone)
198        : it_(target->bits_ == NULL
199              ? new(zone) BitVector(1, zone)
200              : target->bits_) { }
201    bool Done() const { return it_.Done(); }
202    void Advance() { it_.Advance(); }
203    int Current() const { return it_.Current(); }
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() { if (bits_ != NULL) bits_->Clear(); }
229
230 private:
231  static const int kInitialLength = 1024;
232
233  bool InBitsRange(int value) const {
234    return bits_ != NULL && bits_->length() > value;
235  }
236
237  void EnsureCapacity(int value, Zone* zone) {
238    if (InBitsRange(value)) return;
239    int new_length = bits_ == NULL ? kInitialLength : bits_->length();
240    while (new_length <= value) new_length *= 2;
241    BitVector* new_bits = new(zone) BitVector(new_length, zone);
242    if (bits_ != NULL) new_bits->CopyFrom(*bits_);
243    bits_ = new_bits;
244  }
245
246  BitVector* bits_;
247};
248
249}  // namespace internal
250}  // namespace v8
251
252#endif  // V8_DATAFLOW_H_
253