1//== RangeConstraintManager.cpp - Manage range constraints.------*- C++ -*--==//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file defines RangeConstraintManager, a class that tracks simple
11//  equality and inequality constraints on symbolic values of ProgramState.
12//
13//===----------------------------------------------------------------------===//
14
15#include "SimpleConstraintManager.h"
16#include "clang/StaticAnalyzer/Core/PathSensitive/APSIntType.h"
17#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
18#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
19#include "llvm/ADT/FoldingSet.h"
20#include "llvm/ADT/ImmutableSet.h"
21#include "llvm/Support/Debug.h"
22#include "llvm/Support/raw_ostream.h"
23
24using namespace clang;
25using namespace ento;
26
27/// A Range represents the closed range [from, to].  The caller must
28/// guarantee that from <= to.  Note that Range is immutable, so as not
29/// to subvert RangeSet's immutability.
30namespace {
31class Range : public std::pair<const llvm::APSInt*,
32                                                const llvm::APSInt*> {
33public:
34  Range(const llvm::APSInt &from, const llvm::APSInt &to)
35    : std::pair<const llvm::APSInt*, const llvm::APSInt*>(&from, &to) {
36    assert(from <= to);
37  }
38  bool Includes(const llvm::APSInt &v) const {
39    return *first <= v && v <= *second;
40  }
41  const llvm::APSInt &From() const {
42    return *first;
43  }
44  const llvm::APSInt &To() const {
45    return *second;
46  }
47  const llvm::APSInt *getConcreteValue() const {
48    return &From() == &To() ? &From() : nullptr;
49  }
50
51  void Profile(llvm::FoldingSetNodeID &ID) const {
52    ID.AddPointer(&From());
53    ID.AddPointer(&To());
54  }
55};
56
57
58class RangeTrait : public llvm::ImutContainerInfo<Range> {
59public:
60  // When comparing if one Range is less than another, we should compare
61  // the actual APSInt values instead of their pointers.  This keeps the order
62  // consistent (instead of comparing by pointer values) and can potentially
63  // be used to speed up some of the operations in RangeSet.
64  static inline bool isLess(key_type_ref lhs, key_type_ref rhs) {
65    return *lhs.first < *rhs.first || (!(*rhs.first < *lhs.first) &&
66                                       *lhs.second < *rhs.second);
67  }
68};
69
70/// RangeSet contains a set of ranges. If the set is empty, then
71///  there the value of a symbol is overly constrained and there are no
72///  possible values for that symbol.
73class RangeSet {
74  typedef llvm::ImmutableSet<Range, RangeTrait> PrimRangeSet;
75  PrimRangeSet ranges; // no need to make const, since it is an
76                       // ImmutableSet - this allows default operator=
77                       // to work.
78public:
79  typedef PrimRangeSet::Factory Factory;
80  typedef PrimRangeSet::iterator iterator;
81
82  RangeSet(PrimRangeSet RS) : ranges(RS) {}
83
84  /// Create a new set with all ranges of this set and RS.
85  /// Possible intersections are not checked here.
86  RangeSet addRange(Factory &F, const RangeSet &RS) {
87    PrimRangeSet Ranges(RS.ranges);
88    for (const auto &range : ranges)
89      Ranges = F.add(Ranges, range);
90    return RangeSet(Ranges);
91  }
92
93  iterator begin() const { return ranges.begin(); }
94  iterator end() const { return ranges.end(); }
95
96  bool isEmpty() const { return ranges.isEmpty(); }
97
98  /// Construct a new RangeSet representing '{ [from, to] }'.
99  RangeSet(Factory &F, const llvm::APSInt &from, const llvm::APSInt &to)
100    : ranges(F.add(F.getEmptySet(), Range(from, to))) {}
101
102  /// Profile - Generates a hash profile of this RangeSet for use
103  ///  by FoldingSet.
104  void Profile(llvm::FoldingSetNodeID &ID) const { ranges.Profile(ID); }
105
106  /// getConcreteValue - If a symbol is contrained to equal a specific integer
107  ///  constant then this method returns that value.  Otherwise, it returns
108  ///  NULL.
109  const llvm::APSInt* getConcreteValue() const {
110    return ranges.isSingleton() ? ranges.begin()->getConcreteValue() : nullptr;
111  }
112
113private:
114  void IntersectInRange(BasicValueFactory &BV, Factory &F,
115                        const llvm::APSInt &Lower,
116                        const llvm::APSInt &Upper,
117                        PrimRangeSet &newRanges,
118                        PrimRangeSet::iterator &i,
119                        PrimRangeSet::iterator &e) const {
120    // There are six cases for each range R in the set:
121    //   1. R is entirely before the intersection range.
122    //   2. R is entirely after the intersection range.
123    //   3. R contains the entire intersection range.
124    //   4. R starts before the intersection range and ends in the middle.
125    //   5. R starts in the middle of the intersection range and ends after it.
126    //   6. R is entirely contained in the intersection range.
127    // These correspond to each of the conditions below.
128    for (/* i = begin(), e = end() */; i != e; ++i) {
129      if (i->To() < Lower) {
130        continue;
131      }
132      if (i->From() > Upper) {
133        break;
134      }
135
136      if (i->Includes(Lower)) {
137        if (i->Includes(Upper)) {
138          newRanges = F.add(newRanges, Range(BV.getValue(Lower),
139                                             BV.getValue(Upper)));
140          break;
141        } else
142          newRanges = F.add(newRanges, Range(BV.getValue(Lower), i->To()));
143      } else {
144        if (i->Includes(Upper)) {
145          newRanges = F.add(newRanges, Range(i->From(), BV.getValue(Upper)));
146          break;
147        } else
148          newRanges = F.add(newRanges, *i);
149      }
150    }
151  }
152
153  const llvm::APSInt &getMinValue() const {
154    assert(!isEmpty());
155    return ranges.begin()->From();
156  }
157
158  bool pin(llvm::APSInt &Lower, llvm::APSInt &Upper) const {
159    // This function has nine cases, the cartesian product of range-testing
160    // both the upper and lower bounds against the symbol's type.
161    // Each case requires a different pinning operation.
162    // The function returns false if the described range is entirely outside
163    // the range of values for the associated symbol.
164    APSIntType Type(getMinValue());
165    APSIntType::RangeTestResultKind LowerTest = Type.testInRange(Lower, true);
166    APSIntType::RangeTestResultKind UpperTest = Type.testInRange(Upper, true);
167
168    switch (LowerTest) {
169    case APSIntType::RTR_Below:
170      switch (UpperTest) {
171      case APSIntType::RTR_Below:
172        // The entire range is outside the symbol's set of possible values.
173        // If this is a conventionally-ordered range, the state is infeasible.
174        if (Lower < Upper)
175          return false;
176
177        // However, if the range wraps around, it spans all possible values.
178        Lower = Type.getMinValue();
179        Upper = Type.getMaxValue();
180        break;
181      case APSIntType::RTR_Within:
182        // The range starts below what's possible but ends within it. Pin.
183        Lower = Type.getMinValue();
184        Type.apply(Upper);
185        break;
186      case APSIntType::RTR_Above:
187        // The range spans all possible values for the symbol. Pin.
188        Lower = Type.getMinValue();
189        Upper = Type.getMaxValue();
190        break;
191      }
192      break;
193    case APSIntType::RTR_Within:
194      switch (UpperTest) {
195      case APSIntType::RTR_Below:
196        // The range wraps around, but all lower values are not possible.
197        Type.apply(Lower);
198        Upper = Type.getMaxValue();
199        break;
200      case APSIntType::RTR_Within:
201        // The range may or may not wrap around, but both limits are valid.
202        Type.apply(Lower);
203        Type.apply(Upper);
204        break;
205      case APSIntType::RTR_Above:
206        // The range starts within what's possible but ends above it. Pin.
207        Type.apply(Lower);
208        Upper = Type.getMaxValue();
209        break;
210      }
211      break;
212    case APSIntType::RTR_Above:
213      switch (UpperTest) {
214      case APSIntType::RTR_Below:
215        // The range wraps but is outside the symbol's set of possible values.
216        return false;
217      case APSIntType::RTR_Within:
218        // The range starts above what's possible but ends within it (wrap).
219        Lower = Type.getMinValue();
220        Type.apply(Upper);
221        break;
222      case APSIntType::RTR_Above:
223        // The entire range is outside the symbol's set of possible values.
224        // If this is a conventionally-ordered range, the state is infeasible.
225        if (Lower < Upper)
226          return false;
227
228        // However, if the range wraps around, it spans all possible values.
229        Lower = Type.getMinValue();
230        Upper = Type.getMaxValue();
231        break;
232      }
233      break;
234    }
235
236    return true;
237  }
238
239public:
240  // Returns a set containing the values in the receiving set, intersected with
241  // the closed range [Lower, Upper]. Unlike the Range type, this range uses
242  // modular arithmetic, corresponding to the common treatment of C integer
243  // overflow. Thus, if the Lower bound is greater than the Upper bound, the
244  // range is taken to wrap around. This is equivalent to taking the
245  // intersection with the two ranges [Min, Upper] and [Lower, Max],
246  // or, alternatively, /removing/ all integers between Upper and Lower.
247  RangeSet Intersect(BasicValueFactory &BV, Factory &F,
248                     llvm::APSInt Lower, llvm::APSInt Upper) const {
249    if (!pin(Lower, Upper))
250      return F.getEmptySet();
251
252    PrimRangeSet newRanges = F.getEmptySet();
253
254    PrimRangeSet::iterator i = begin(), e = end();
255    if (Lower <= Upper)
256      IntersectInRange(BV, F, Lower, Upper, newRanges, i, e);
257    else {
258      // The order of the next two statements is important!
259      // IntersectInRange() does not reset the iteration state for i and e.
260      // Therefore, the lower range most be handled first.
261      IntersectInRange(BV, F, BV.getMinValue(Upper), Upper, newRanges, i, e);
262      IntersectInRange(BV, F, Lower, BV.getMaxValue(Lower), newRanges, i, e);
263    }
264
265    return newRanges;
266  }
267
268  void print(raw_ostream &os) const {
269    bool isFirst = true;
270    os << "{ ";
271    for (iterator i = begin(), e = end(); i != e; ++i) {
272      if (isFirst)
273        isFirst = false;
274      else
275        os << ", ";
276
277      os << '[' << i->From().toString(10) << ", " << i->To().toString(10)
278         << ']';
279    }
280    os << " }";
281  }
282
283  bool operator==(const RangeSet &other) const {
284    return ranges == other.ranges;
285  }
286};
287} // end anonymous namespace
288
289REGISTER_TRAIT_WITH_PROGRAMSTATE(ConstraintRange,
290                                 CLANG_ENTO_PROGRAMSTATE_MAP(SymbolRef,
291                                                             RangeSet))
292
293namespace {
294class RangeConstraintManager : public SimpleConstraintManager{
295  RangeSet GetRange(ProgramStateRef state, SymbolRef sym);
296public:
297  RangeConstraintManager(SubEngine *subengine, SValBuilder &SVB)
298    : SimpleConstraintManager(subengine, SVB) {}
299
300  ProgramStateRef assumeSymNE(ProgramStateRef state, SymbolRef sym,
301                             const llvm::APSInt& Int,
302                             const llvm::APSInt& Adjustment) override;
303
304  ProgramStateRef assumeSymEQ(ProgramStateRef state, SymbolRef sym,
305                             const llvm::APSInt& Int,
306                             const llvm::APSInt& Adjustment) override;
307
308  ProgramStateRef assumeSymLT(ProgramStateRef state, SymbolRef sym,
309                             const llvm::APSInt& Int,
310                             const llvm::APSInt& Adjustment) override;
311
312  ProgramStateRef assumeSymGT(ProgramStateRef state, SymbolRef sym,
313                             const llvm::APSInt& Int,
314                             const llvm::APSInt& Adjustment) override;
315
316  ProgramStateRef assumeSymGE(ProgramStateRef state, SymbolRef sym,
317                             const llvm::APSInt& Int,
318                             const llvm::APSInt& Adjustment) override;
319
320  ProgramStateRef assumeSymLE(ProgramStateRef state, SymbolRef sym,
321                             const llvm::APSInt& Int,
322                             const llvm::APSInt& Adjustment) override;
323
324  ProgramStateRef assumeSymbolWithinInclusiveRange(
325        ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
326        const llvm::APSInt &To, const llvm::APSInt &Adjustment) override;
327
328  ProgramStateRef assumeSymbolOutOfInclusiveRange(
329        ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
330        const llvm::APSInt &To, const llvm::APSInt &Adjustment) override;
331
332  const llvm::APSInt* getSymVal(ProgramStateRef St,
333                                SymbolRef sym) const override;
334  ConditionTruthVal checkNull(ProgramStateRef State, SymbolRef Sym) override;
335
336  ProgramStateRef removeDeadBindings(ProgramStateRef St,
337                                     SymbolReaper& SymReaper) override;
338
339  void print(ProgramStateRef St, raw_ostream &Out,
340             const char* nl, const char *sep) override;
341
342private:
343  RangeSet::Factory F;
344  RangeSet getSymLTRange(ProgramStateRef St, SymbolRef Sym,
345                         const llvm::APSInt &Int,
346                         const llvm::APSInt &Adjustment);
347  RangeSet getSymGTRange(ProgramStateRef St, SymbolRef Sym,
348                         const llvm::APSInt &Int,
349                         const llvm::APSInt &Adjustment);
350  RangeSet getSymLERange(ProgramStateRef St, SymbolRef Sym,
351                         const llvm::APSInt &Int,
352                         const llvm::APSInt &Adjustment);
353  RangeSet getSymLERange(const RangeSet &RS, const llvm::APSInt &Int,
354                         const llvm::APSInt &Adjustment);
355  RangeSet getSymGERange(ProgramStateRef St, SymbolRef Sym,
356                         const llvm::APSInt &Int,
357                         const llvm::APSInt &Adjustment);
358};
359
360} // end anonymous namespace
361
362std::unique_ptr<ConstraintManager>
363ento::CreateRangeConstraintManager(ProgramStateManager &StMgr, SubEngine *Eng) {
364  return llvm::make_unique<RangeConstraintManager>(Eng, StMgr.getSValBuilder());
365}
366
367const llvm::APSInt* RangeConstraintManager::getSymVal(ProgramStateRef St,
368                                                      SymbolRef sym) const {
369  const ConstraintRangeTy::data_type *T = St->get<ConstraintRange>(sym);
370  return T ? T->getConcreteValue() : nullptr;
371}
372
373ConditionTruthVal RangeConstraintManager::checkNull(ProgramStateRef State,
374                                                    SymbolRef Sym) {
375  const RangeSet *Ranges = State->get<ConstraintRange>(Sym);
376
377  // If we don't have any information about this symbol, it's underconstrained.
378  if (!Ranges)
379    return ConditionTruthVal();
380
381  // If we have a concrete value, see if it's zero.
382  if (const llvm::APSInt *Value = Ranges->getConcreteValue())
383    return *Value == 0;
384
385  BasicValueFactory &BV = getBasicVals();
386  APSIntType IntType = BV.getAPSIntType(Sym->getType());
387  llvm::APSInt Zero = IntType.getZeroValue();
388
389  // Check if zero is in the set of possible values.
390  if (Ranges->Intersect(BV, F, Zero, Zero).isEmpty())
391    return false;
392
393  // Zero is a possible value, but it is not the /only/ possible value.
394  return ConditionTruthVal();
395}
396
397/// Scan all symbols referenced by the constraints. If the symbol is not alive
398/// as marked in LSymbols, mark it as dead in DSymbols.
399ProgramStateRef
400RangeConstraintManager::removeDeadBindings(ProgramStateRef state,
401                                           SymbolReaper& SymReaper) {
402
403  ConstraintRangeTy CR = state->get<ConstraintRange>();
404  ConstraintRangeTy::Factory& CRFactory = state->get_context<ConstraintRange>();
405
406  for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
407    SymbolRef sym = I.getKey();
408    if (SymReaper.maybeDead(sym))
409      CR = CRFactory.remove(CR, sym);
410  }
411
412  return state->set<ConstraintRange>(CR);
413}
414
415RangeSet
416RangeConstraintManager::GetRange(ProgramStateRef state, SymbolRef sym) {
417  if (ConstraintRangeTy::data_type* V = state->get<ConstraintRange>(sym))
418    return *V;
419
420  // Lazily generate a new RangeSet representing all possible values for the
421  // given symbol type.
422  BasicValueFactory &BV = getBasicVals();
423  QualType T = sym->getType();
424
425  RangeSet Result(F, BV.getMinValue(T), BV.getMaxValue(T));
426
427  // Special case: references are known to be non-zero.
428  if (T->isReferenceType()) {
429    APSIntType IntType = BV.getAPSIntType(T);
430    Result = Result.Intersect(BV, F, ++IntType.getZeroValue(),
431                                     --IntType.getZeroValue());
432  }
433
434  return Result;
435}
436
437//===------------------------------------------------------------------------===
438// assumeSymX methods: public interface for RangeConstraintManager.
439//===------------------------------------------------------------------------===/
440
441// The syntax for ranges below is mathematical, using [x, y] for closed ranges
442// and (x, y) for open ranges. These ranges are modular, corresponding with
443// a common treatment of C integer overflow. This means that these methods
444// do not have to worry about overflow; RangeSet::Intersect can handle such a
445// "wraparound" range.
446// As an example, the range [UINT_MAX-1, 3) contains five values: UINT_MAX-1,
447// UINT_MAX, 0, 1, and 2.
448
449ProgramStateRef
450RangeConstraintManager::assumeSymNE(ProgramStateRef St, SymbolRef Sym,
451                                    const llvm::APSInt &Int,
452                                    const llvm::APSInt &Adjustment) {
453  // Before we do any real work, see if the value can even show up.
454  APSIntType AdjustmentType(Adjustment);
455  if (AdjustmentType.testInRange(Int, true) != APSIntType::RTR_Within)
456    return St;
457
458  llvm::APSInt Lower = AdjustmentType.convert(Int) - Adjustment;
459  llvm::APSInt Upper = Lower;
460  --Lower;
461  ++Upper;
462
463  // [Int-Adjustment+1, Int-Adjustment-1]
464  // Notice that the lower bound is greater than the upper bound.
465  RangeSet New = GetRange(St, Sym).Intersect(getBasicVals(), F, Upper, Lower);
466  return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
467}
468
469ProgramStateRef
470RangeConstraintManager::assumeSymEQ(ProgramStateRef St, SymbolRef Sym,
471                                    const llvm::APSInt &Int,
472                                    const llvm::APSInt &Adjustment) {
473  // Before we do any real work, see if the value can even show up.
474  APSIntType AdjustmentType(Adjustment);
475  if (AdjustmentType.testInRange(Int, true) != APSIntType::RTR_Within)
476    return nullptr;
477
478  // [Int-Adjustment, Int-Adjustment]
479  llvm::APSInt AdjInt = AdjustmentType.convert(Int) - Adjustment;
480  RangeSet New = GetRange(St, Sym).Intersect(getBasicVals(), F, AdjInt, AdjInt);
481  return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
482}
483
484RangeSet RangeConstraintManager::getSymLTRange(ProgramStateRef St,
485                                               SymbolRef Sym,
486                                               const llvm::APSInt &Int,
487                                               const llvm::APSInt &Adjustment) {
488  // Before we do any real work, see if the value can even show up.
489  APSIntType AdjustmentType(Adjustment);
490  switch (AdjustmentType.testInRange(Int, true)) {
491  case APSIntType::RTR_Below:
492    return F.getEmptySet();
493  case APSIntType::RTR_Within:
494    break;
495  case APSIntType::RTR_Above:
496    return GetRange(St, Sym);
497  }
498
499  // Special case for Int == Min. This is always false.
500  llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
501  llvm::APSInt Min = AdjustmentType.getMinValue();
502  if (ComparisonVal == Min)
503    return F.getEmptySet();
504
505  llvm::APSInt Lower = Min - Adjustment;
506  llvm::APSInt Upper = ComparisonVal - Adjustment;
507  --Upper;
508
509  return GetRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
510}
511
512ProgramStateRef
513RangeConstraintManager::assumeSymLT(ProgramStateRef St, SymbolRef Sym,
514                                    const llvm::APSInt &Int,
515                                    const llvm::APSInt &Adjustment) {
516  RangeSet New = getSymLTRange(St, Sym, Int, Adjustment);
517  return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
518}
519
520RangeSet
521RangeConstraintManager::getSymGTRange(ProgramStateRef St, SymbolRef Sym,
522                                      const llvm::APSInt &Int,
523                                      const llvm::APSInt &Adjustment) {
524  // Before we do any real work, see if the value can even show up.
525  APSIntType AdjustmentType(Adjustment);
526  switch (AdjustmentType.testInRange(Int, true)) {
527  case APSIntType::RTR_Below:
528    return GetRange(St, Sym);
529  case APSIntType::RTR_Within:
530    break;
531  case APSIntType::RTR_Above:
532    return F.getEmptySet();
533  }
534
535  // Special case for Int == Max. This is always false.
536  llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
537  llvm::APSInt Max = AdjustmentType.getMaxValue();
538  if (ComparisonVal == Max)
539    return F.getEmptySet();
540
541  llvm::APSInt Lower = ComparisonVal - Adjustment;
542  llvm::APSInt Upper = Max - Adjustment;
543  ++Lower;
544
545  return GetRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
546}
547
548ProgramStateRef
549RangeConstraintManager::assumeSymGT(ProgramStateRef St, SymbolRef Sym,
550                                    const llvm::APSInt &Int,
551                                    const llvm::APSInt &Adjustment) {
552  RangeSet New = getSymGTRange(St, Sym, Int, Adjustment);
553  return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
554}
555
556RangeSet
557RangeConstraintManager::getSymGERange(ProgramStateRef St, SymbolRef Sym,
558                                      const llvm::APSInt &Int,
559                                      const llvm::APSInt &Adjustment) {
560  // Before we do any real work, see if the value can even show up.
561  APSIntType AdjustmentType(Adjustment);
562  switch (AdjustmentType.testInRange(Int, true)) {
563  case APSIntType::RTR_Below:
564    return GetRange(St, Sym);
565  case APSIntType::RTR_Within:
566    break;
567  case APSIntType::RTR_Above:
568    return F.getEmptySet();
569  }
570
571  // Special case for Int == Min. This is always feasible.
572  llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
573  llvm::APSInt Min = AdjustmentType.getMinValue();
574  if (ComparisonVal == Min)
575    return GetRange(St, Sym);
576
577  llvm::APSInt Max = AdjustmentType.getMaxValue();
578  llvm::APSInt Lower = ComparisonVal - Adjustment;
579  llvm::APSInt Upper = Max - Adjustment;
580
581  return GetRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
582}
583
584ProgramStateRef
585RangeConstraintManager::assumeSymGE(ProgramStateRef St, SymbolRef Sym,
586                                    const llvm::APSInt &Int,
587                                    const llvm::APSInt &Adjustment) {
588  RangeSet New = getSymGERange(St, Sym, Int, Adjustment);
589  return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
590}
591
592RangeSet
593RangeConstraintManager::getSymLERange(const RangeSet &RS,
594                                      const llvm::APSInt &Int,
595                                      const llvm::APSInt &Adjustment) {
596  // Before we do any real work, see if the value can even show up.
597  APSIntType AdjustmentType(Adjustment);
598  switch (AdjustmentType.testInRange(Int, true)) {
599  case APSIntType::RTR_Below:
600    return F.getEmptySet();
601  case APSIntType::RTR_Within:
602    break;
603  case APSIntType::RTR_Above:
604    return RS;
605  }
606
607  // Special case for Int == Max. This is always feasible.
608  llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
609  llvm::APSInt Max = AdjustmentType.getMaxValue();
610  if (ComparisonVal == Max)
611    return RS;
612
613  llvm::APSInt Min = AdjustmentType.getMinValue();
614  llvm::APSInt Lower = Min - Adjustment;
615  llvm::APSInt Upper = ComparisonVal - Adjustment;
616
617  return RS.Intersect(getBasicVals(), F, Lower, Upper);
618}
619
620RangeSet
621RangeConstraintManager::getSymLERange(ProgramStateRef St, SymbolRef Sym,
622                                      const llvm::APSInt &Int,
623                                      const llvm::APSInt &Adjustment) {
624  // Before we do any real work, see if the value can even show up.
625  APSIntType AdjustmentType(Adjustment);
626  switch (AdjustmentType.testInRange(Int, true)) {
627  case APSIntType::RTR_Below:
628    return F.getEmptySet();
629  case APSIntType::RTR_Within:
630    break;
631  case APSIntType::RTR_Above:
632    return GetRange(St, Sym);
633  }
634
635  // Special case for Int == Max. This is always feasible.
636  llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
637  llvm::APSInt Max = AdjustmentType.getMaxValue();
638  if (ComparisonVal == Max)
639    return GetRange(St, Sym);
640
641  llvm::APSInt Min = AdjustmentType.getMinValue();
642  llvm::APSInt Lower = Min - Adjustment;
643  llvm::APSInt Upper = ComparisonVal - Adjustment;
644
645  return GetRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
646}
647
648ProgramStateRef
649RangeConstraintManager::assumeSymLE(ProgramStateRef St, SymbolRef Sym,
650                                    const llvm::APSInt &Int,
651                                    const llvm::APSInt &Adjustment) {
652  RangeSet New = getSymLERange(St, Sym, Int, Adjustment);
653  return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
654}
655
656ProgramStateRef
657RangeConstraintManager::assumeSymbolWithinInclusiveRange(
658    ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
659    const llvm::APSInt &To, const llvm::APSInt &Adjustment) {
660  RangeSet New = getSymGERange(State, Sym, From, Adjustment);
661  if (New.isEmpty())
662    return nullptr;
663  New = getSymLERange(New, To, Adjustment);
664  return New.isEmpty() ? nullptr : State->set<ConstraintRange>(Sym, New);
665}
666
667ProgramStateRef
668RangeConstraintManager::assumeSymbolOutOfInclusiveRange(
669    ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
670    const llvm::APSInt &To, const llvm::APSInt &Adjustment) {
671  RangeSet RangeLT = getSymLTRange(State, Sym, From, Adjustment);
672  RangeSet RangeGT = getSymGTRange(State, Sym, To, Adjustment);
673  RangeSet New(RangeLT.addRange(F, RangeGT));
674  return New.isEmpty() ? nullptr : State->set<ConstraintRange>(Sym, New);
675}
676
677//===------------------------------------------------------------------------===
678// Pretty-printing.
679//===------------------------------------------------------------------------===/
680
681void RangeConstraintManager::print(ProgramStateRef St, raw_ostream &Out,
682                                   const char* nl, const char *sep) {
683
684  ConstraintRangeTy Ranges = St->get<ConstraintRange>();
685
686  if (Ranges.isEmpty()) {
687    Out << nl << sep << "Ranges are empty." << nl;
688    return;
689  }
690
691  Out << nl << sep << "Ranges of symbol values:";
692  for (ConstraintRangeTy::iterator I=Ranges.begin(), E=Ranges.end(); I!=E; ++I){
693    Out << nl << ' ' << I.getKey() << " : ";
694    I.getData().print(Out);
695  }
696  Out << nl;
697}
698