GCC Code Coverage Report
Directory: . Exec Total Coverage
File: src/prop/minisat/core/SolverTypes.h Lines: 140 160 87.5 %
Date: 2021-08-14 Branches: 67 190 35.3 %

Line Exec Source
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/***********************************************************************************[SolverTypes.h]
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Copyright (c) 2003-2006, Niklas Een, Niklas Sorensson
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Copyright (c) 2007-2010, Niklas Sorensson
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Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
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associated documentation files (the "Software"), to deal in the Software without restriction,
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including without limitation the rights to use, copy, modify, merge, publish, distribute,
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sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all copies or
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substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
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NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
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OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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**************************************************************************************************/
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#include "cvc5_private.h"
22
23
#ifndef Minisat_SolverTypes_h
24
#define Minisat_SolverTypes_h
25
26
#include "base/check.h"
27
#include "base/output.h"
28
#include "prop/minisat/mtl/Alg.h"
29
#include "prop/minisat/mtl/Alloc.h"
30
#include "prop/minisat/mtl/IntTypes.h"
31
#include "prop/minisat/mtl/Map.h"
32
#include "prop/minisat/mtl/Vec.h"
33
34
namespace cvc5 {
35
namespace Minisat {
36
37
class Solver;
38
39
//=================================================================================================
40
// Variables, literals, lifted booleans, clauses:
41
42
43
// NOTE! Variables are just integers. No abstraction here. They should be chosen from 0..N,
44
// so that they can be used as array indices.
45
46
typedef int Var;
47
#define var_Undef (-1)
48
49
50
51
struct Lit {
52
    int     x;
53
54
    // Use this as a constructor:
55
    friend Lit mkLit(Var var, bool sign);
56
57
4082690672
    bool operator == (Lit p) const { return x == p.x; }
58
336356709
    bool operator != (Lit p) const { return x != p.x; }
59
38049688
    bool operator <  (Lit p) const { return x < p.x;  } // '<' makes p, ~p adjacent in the ordering.
60
};
61
62
63
73133285
inline  Lit  mkLit     (Var var, bool sign = false) { Lit p; p.x = var + var + (int)sign; return p; }
64
1441807991
inline  Lit  operator ~(Lit p)              { Lit q; q.x = p.x ^ 1; return q; }
65
inline  Lit  operator ^(Lit p, bool b)      { Lit q; q.x = p.x ^ (unsigned int)b; return q; }
66
2623654302
inline  bool sign      (Lit p)              { return p.x & 1; }
67
7444973488
inline  int  var       (Lit p)              { return p.x >> 1; }
68
69
// Mapping Literals to and from compact integers suitable for array indexing:
70
14707485
inline int toInt(Var v) { return v; }
71
320348691
inline int toInt(Lit p) { return p.x; }
72
72533
inline Lit toLit(int i)
73
{
74
  Lit p;
75
72533
  p.x = i;
76
72533
  return p;
77
}
78
79
//const Lit lit_Undef = mkLit(var_Undef, false);  // }- Useful special constants.
80
//const Lit lit_Error = mkLit(var_Undef, true );  // }
81
82
const Lit lit_Undef = { -2 };  // }- Useful special constants.
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const Lit lit_Error = { -1 };  // }
84
85
//=================================================================================================
86
// Lifted booleans:
87
//
88
// NOTE: this implementation is optimized for the case when comparisons between
89
// values are mostly
90
//       between one variable and one constant. Some care had to be taken to
91
//       make sure that gcc does enough constant propagation to produce sensible
92
//       code, and this appears to be somewhat fragile unfortunately.
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94
/*
95
  This is to avoid multiple definitions of l_True, l_False and l_Undef if using
96
  multiple copies of Minisat. IMPORTANT: if we you change the value of the
97
  constants so that it is not the same in all copies of Minisat this breaks!
98
 */
99
100
#ifndef l_True
101
#define l_True  (lbool((uint8_t)0)) // gcc does not do constant propagation if these are real constants.
102
#endif
103
104
#ifndef l_False
105
#define l_False (lbool((uint8_t)1))
106
#endif
107
108
#ifndef l_Undef
109
#define l_Undef (lbool((uint8_t)2))
110
#endif
111
112
class lbool {
113
    uint8_t value;
114
115
public:
116
4894155038
    explicit lbool(uint8_t v) : value(v) { }
117
118
609091
    lbool()       : value(0) { }
119
116612483
    explicit lbool(bool x) : value(!x) { }
120
121
2412438755
    bool  operator == (lbool b) const { return ((b.value&2) & (value&2)) | (!(b.value&2)&(value == b.value)); }
122
1175458066
    bool  operator != (lbool b) const { return !(*this == b); }
123
2370769823
    lbool operator ^  (bool  b) const { return lbool((uint8_t)(value^(uint8_t)b)); }
124
125
    lbool operator&&(lbool b) const
126
    {
127
      uint8_t sel = (this->value << 1) | (b.value << 3);
128
      uint8_t v = (0xF7F755F4 >> sel) & 3;
129
      return lbool(v);
130
    }
131
132
    lbool operator || (lbool b) const {
133
        uint8_t sel = (this->value << 1) | (b.value << 3);
134
        uint8_t v   = (0xFCFCF400 >> sel) & 3;
135
        return lbool(v); }
136
137
    friend int   toInt  (lbool l);
138
    friend lbool toLbool(int   v);
139
};
140
inline int   toInt  (lbool l) { return l.value; }
141
inline lbool toLbool(int   v) { return lbool((uint8_t)v);  }
142
143
144
class Clause;
145
typedef RegionAllocator<uint32_t>::Ref CRef;
146
147
/* convenience printing functions */
148
149
150
inline std::ostream& operator <<(std::ostream& out, Minisat::Lit lit) {
151
  const char * s = (Minisat::sign(lit)) ? "~" : " ";
152
  out << s << Minisat::var(lit);
153
  return out;
154
}
155
156
inline std::ostream& operator <<(std::ostream& out, Minisat::vec<Minisat::Lit>& clause) {
157
  out << "clause:";
158
  for(int i = 0; i < clause.size(); ++i) {
159
    out << " " << clause[i];
160
  }
161
  out << ";";
162
  return out;
163
}
164
165
inline std::ostream& operator <<(std::ostream& out, Minisat::lbool val) {
166
  std::string val_str;
167
  if( val == l_False ) {
168
    val_str = "0";
169
  } else if (val == l_True ) {
170
    val_str = "1";
171
  } else { // unknown
172
    val_str = "_";
173
  }
174
175
  out << val_str;
176
  return out;
177
}
178
179
}  // namespace Minisat
180
}  // namespace cvc5
181
182
namespace cvc5 {
183
namespace Minisat{
184
185
//=================================================================================================
186
// Clause -- a simple class for representing a clause:
187
188
class Clause {
189
    struct {
190
        unsigned mark      : 2;
191
        unsigned removable : 1;
192
        unsigned has_extra : 1;
193
        unsigned reloced   : 1;
194
        unsigned size      : 27;
195
        unsigned level     : 32; }                            header;
196
    union { Lit lit; float act; uint32_t abs; CRef rel; } data[0];
197
198
    friend class ClauseAllocator;
199
200
    // NOTE: This constructor cannot be used directly (doesn't allocate enough memory).
201
    template<class V>
202
5769773
    Clause(const V& ps, bool use_extra, bool removable, int level) {
203
5769773
        header.mark      = 0;
204
5769773
        header.removable = removable;
205
5769773
        header.has_extra = use_extra;
206
5769773
        header.reloced   = 0;
207
5769773
        header.size      = ps.size();
208
5769773
        header.level     = level;
209
210
5769773
        for (int i = 0; i < ps.size(); i++) data[i].lit = ps[i];
211
212
5769773
        if (header.has_extra){
213
5769773
            if (header.removable)
214
708851
              data[header.size].act = 0;
215
            else
216
5060922
              calcAbstraction();
217
        }
218
5769773
    }
219
220
public:
221
6789929
    void calcAbstraction() {
222
6789929
      Assert(header.has_extra);
223
6789929
      uint32_t abstraction = 0;
224
28240662
      for (int i = 0; i < size(); i++)
225
21450733
        abstraction |= 1 << (var(data[i].lit) & 31);
226
6789929
      data[header.size].abs = abstraction;
227
6789929
    }
228
229
90773462
    int          level       ()      const   { return header.level; }
230
1765038278
    int          size        ()      const   { return header.size; }
231
98105
    void shrink(int i)
232
    {
233
98105
      Assert(i <= size());
234
98105
      if (header.has_extra) data[header.size - i] = data[header.size];
235
98105
      header.size -= i;
236
98105
    }
237
98105
    void         pop         ()              { shrink(1); }
238
42375887
    bool         removable   ()      const   { return header.removable; }
239
2345491
    bool         has_extra   ()      const   { return header.has_extra; }
240
80329629
    uint32_t     mark        ()      const   { return header.mark; }
241
3798417
    void         mark        (uint32_t m)    { header.mark = m; }
242
    const Lit&   last        ()      const   { return data[header.size-1].lit; }
243
244
6094090
    bool         reloced     ()      const   { return header.reloced; }
245
4262841
    CRef         relocation  ()      const   { return data[0].rel; }
246
1793573
    void         relocate    (CRef c)        { header.reloced = 1; data[0].rel = c; }
247
248
    // NOTE: somewhat unsafe to change the clause in-place! Must manually call 'calcAbstraction' afterwards for
249
    //       subsumption operations to behave correctly.
250
3313117355
    Lit&         operator [] (int i)         { return data[i].lit; }
251
63802348
    Lit          operator [] (int i) const   { return data[i].lit; }
252
8727432
    operator const Lit* (void) const         { return (Lit*)data; }
253
254
9692649
    float& activity()
255
    {
256
9692649
      Assert(header.has_extra);
257
9692649
      return data[header.size].act;
258
    }
259
    uint32_t abstraction() const
260
    {
261
      Assert(header.has_extra);
262
      return data[header.size].abs;
263
    }
264
265
    Lit          subsumes    (const Clause& other) const;
266
    void         strengthen  (Lit p);
267
};
268
269
270
//=================================================================================================
271
// ClauseAllocator -- a simple class for allocating memory for clauses:
272
273
274
const CRef CRef_Undef = RegionAllocator<uint32_t>::Ref_Undef;
275
const CRef CRef_Lazy  = RegionAllocator<uint32_t>::Ref_Undef - 1;
276
12698
class ClauseAllocator : public RegionAllocator<uint32_t>
277
{
278
6506733
    static int clauseWord32Size(int size, bool has_extra){
279
6506733
        return (sizeof(Clause) + (sizeof(Lit) * (size + (int)has_extra))) / sizeof(uint32_t); }
280
 public:
281
    bool extra_clause_field;
282
283
2778
    ClauseAllocator(uint32_t start_cap) : RegionAllocator<uint32_t>(start_cap), extra_clause_field(false){}
284
9920
    ClauseAllocator() : extra_clause_field(false){}
285
286
2778
    void moveTo(ClauseAllocator& to){
287
2778
        to.extra_clause_field = extra_clause_field;
288
2778
        RegionAllocator<uint32_t>::moveTo(to); }
289
290
    template<class Lits>
291
5769773
    CRef alloc(int level, const Lits& ps, bool removable = false)
292
    {
293
5769773
      Assert(sizeof(Lit) == sizeof(uint32_t));
294
5769773
      Assert(sizeof(float) == sizeof(uint32_t));
295
5769773
      bool use_extra = removable | extra_clause_field;
296
297
5769773
      CRef cid = RegionAllocator<uint32_t>::alloc(
298
          clauseWord32Size(ps.size(), use_extra));
299
5769773
      new (lea(cid)) Clause(ps, use_extra, removable, level);
300
301
5769773
      return cid;
302
    }
303
304
    // Deref, Load Effective Address (LEA), Inverse of LEA (AEL):
305
869339056
    Clause&       operator[](Ref r)       { return (Clause&)RegionAllocator<uint32_t>::operator[](r); }
306
16785363
    const Clause& operator[](Ref r) const { return (Clause&)RegionAllocator<uint32_t>::operator[](r); }
307
5769773
    Clause*       lea       (Ref r)       { return (Clause*)RegionAllocator<uint32_t>::lea(r); }
308
92234
    const Clause* lea       (Ref r) const { return (Clause*)RegionAllocator<uint32_t>::lea(r); }
309
    Ref           ael       (const Clause* t){ return RegionAllocator<uint32_t>::ael((uint32_t*)t); }
310
311
736960
    void free(CRef cid)
312
    {
313
736960
        Clause& c = operator[](cid);
314
736960
        RegionAllocator<uint32_t>::free(clauseWord32Size(c.size(), c.has_extra()));
315
736960
    }
316
317
    void reloc(CRef& cr, ClauseAllocator& to);
318
    // Implementation moved to Solver.cc.
319
};
320
321
322
//=================================================================================================
323
// OccLists -- a class for maintaining occurence lists with lazy deletion:
324
325
template<class Idx, class Vec, class Deleted>
326
19840
class OccLists
327
{
328
    vec<Vec>  occs;
329
    vec<char> dirty;
330
    vec<Idx>  dirties;
331
    Deleted   deleted;
332
333
 public:
334
19840
    OccLists(const Deleted& d) : deleted(d) {}
335
336
2743345
    void  init      (const Idx& idx){ occs.growTo(toInt(idx)+1); dirty.growTo(toInt(idx)+1, 0); }
337
    void  resizeTo  (const Idx& idx);
338
    // Vec&  operator[](const Idx& idx){ return occs[toInt(idx)]; }
339
294350133
    Vec&  operator[](const Idx& idx){ return occs[toInt(idx)]; }
340
969601
    Vec&  lookup    (const Idx& idx){ if (dirty[toInt(idx)]) clean(idx); return occs[toInt(idx)]; }
341
342
    void  cleanAll  ();
343
    void  clean     (const Idx& idx);
344
2195584
    void  smudge    (const Idx& idx){
345
2195584
        if (dirty[toInt(idx)] == 0){
346
662505
            dirty[toInt(idx)] = 1;
347
662505
            dirties.push(idx);
348
        }
349
2195584
    }
350
351
    void  clear(bool free = true){
352
        occs   .clear(free);
353
        dirty  .clear(free);
354
        dirties.clear(free);
355
    }
356
};
357
358
359
template<class Idx, class Vec, class Deleted>
360
4500878
void OccLists<Idx,Vec,Deleted>::cleanAll()
361
{
362
5005972
    for (int i = 0; i < dirties.size(); i++)
363
        // Dirties may contain duplicates so check here if a variable is already cleaned:
364
505094
        if (dirty[toInt(dirties[i])])
365
418782
            clean(dirties[i]);
366
4500878
    dirties.clear();
367
4500878
}
368
369
template<class Idx, class Vec, class Deleted>
370
3069
void OccLists<Idx,Vec,Deleted>::resizeTo(const Idx& idx)
371
{
372
3069
    int shrinkSize = occs.size() - (toInt(idx) + 1);
373
3069
    occs.shrink(shrinkSize);
374
3069
    dirty.shrink(shrinkSize);
375
    // Remove out-of-bound indices from dirties
376
    int  i, j;
377
175635
    for (i = j = 0; i < dirties.size(); i++)
378
172566
        if (toInt(dirties[i]) < occs.size())
379
17842
            dirties[j++] = dirties[i];
380
3069
    dirties.shrink(i - j);
381
3069
}
382
383
template<class Idx, class Vec, class Deleted>
384
505094
void OccLists<Idx,Vec,Deleted>::clean(const Idx& idx)
385
{
386
505094
    Vec& vec = occs[toInt(idx)];
387
    int  i, j;
388
17290457
    for (i = j = 0; i < vec.size(); i++)
389
16785363
        if (!deleted(vec[i]))
390
15135144
            vec[j++] = vec[i];
391
505094
    vec.shrink(i - j);
392
505094
    dirty[toInt(idx)] = 0;
393
505094
}
394
395
396
//=================================================================================================
397
// CMap -- a class for mapping clauses to values:
398
399
400
template<class T>
401
class CMap
402
{
403
    struct CRefHash {
404
        uint32_t operator()(CRef cr) const { return (uint32_t)cr; } };
405
406
    typedef Map<CRef, T, CRefHash> HashTable;
407
    HashTable map;
408
409
 public:
410
    // Size-operations:
411
    void     clear       ()                           { map.clear(); }
412
    int      size        ()                const      { return map.elems(); }
413
414
    // Insert/Remove/Test mapping:
415
    void     insert      (CRef cr, const T& t){ map.insert(cr, t); }
416
    void     growTo      (CRef cr, const T& t){ map.insert(cr, t); } // NOTE: for compatibility
417
    void     remove      (CRef cr)            { map.remove(cr); }
418
    bool     has         (CRef cr, T& t)      { return map.peek(cr, t); }
419
420
    // Vector interface (the clause 'c' must already exist):
421
    const T& operator [] (CRef cr) const      { return map[cr]; }
422
    T&       operator [] (CRef cr)            { return map[cr]; }
423
424
    // Iteration (not transparent at all at the moment):
425
    int  bucket_count() const { return map.bucket_count(); }
426
    const vec<typename HashTable::Pair>& bucket(int i) const { return map.bucket(i); }
427
428
    // Move contents to other map:
429
    void moveTo(CMap& other){ map.moveTo(other.map); }
430
431
    // TMP debug:
432
    void debug(){
433
        printf(" --- size = %d, bucket_count = %d\n", size(), map.bucket_count()); }
434
};
435
436
/*_________________________________________________________________________________________________
437
|
438
|  subsumes : (other : const Clause&)  ->  Lit
439
|
440
|  Description:
441
|       Checks if clause subsumes 'other', and at the same time, if it can be
442
used to simplify 'other' |       by subsumption resolution.
443
|
444
|    Result:
445
|       lit_Error  - No subsumption or simplification
446
|       lit_Undef  - Clause subsumes 'other'
447
|       p          - The literal p can be deleted from 'other'
448
|________________________________________________________________________________________________@*/
449
27200783
inline Lit Clause::subsumes(const Clause& other) const
450
{
451
    // We restrict subsumtion to clauses at higher levels (if !enable_incremantal this should always be false)
452
27200783
    if (level() > other.level()) {
453
      return lit_Error;
454
    }
455
456
    //if (other.size() < size() || (extra.abst & ~other.extra.abst) != 0)
457
    //if (other.size() < size() || (!learnt() && !other.learnt() && (extra.abst & ~other.extra.abst) != 0))
458
27200783
    Assert(!header.removable);
459
27200783
    Assert(!other.header.removable);
460
27200783
    Assert(header.has_extra);
461
27200783
    Assert(other.header.has_extra);
462
27200783
    if (other.header.size < header.size || (data[header.size].abs & ~other.data[other.header.size].abs) != 0)
463
23838942
        return lit_Error;
464
465
3361841
    Lit        ret = lit_Undef;
466
3361841
    const Lit* c   = (const Lit*)(*this);
467
3361841
    const Lit* d   = (const Lit*)other;
468
469
13368351
    for (unsigned i = 0; i < header.size; i++) {
470
        // search for c[i] or ~c[i]
471
1221548960
        for (unsigned j = 0; j < other.header.size; j++)
472
1218426787
            if (c[i] == d[j])
473
8255606
                goto ok;
474
1210171181
            else if (ret == lit_Undef && c[i] == ~d[j]){
475
1750904
                ret = c[i];
476
1750904
                goto ok;
477
            }
478
479
        // did not find it
480
3122173
        return lit_Error;
481
10006510
    ok:;
482
    }
483
484
239668
    return ret;
485
}
486
487
98105
inline void Clause::strengthen(Lit p)
488
{
489
98105
    remove(*this, p);
490
98105
    calcAbstraction();
491
98105
}
492
493
//=================================================================================================
494
}
495
}  // namespace cvc5
496
497
#endif