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 
24 using namespace clang;
25 using 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.
30 namespace {
31 class Range : public std::pair<const llvm::APSInt*,
32                                                 const llvm::APSInt*> {
33 public:
Range(const llvm::APSInt & from,const llvm::APSInt & to)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   }
Includes(const llvm::APSInt & v) const38   bool Includes(const llvm::APSInt &v) const {
39     return *first <= v && v <= *second;
40   }
From() const41   const llvm::APSInt &From() const {
42     return *first;
43   }
To() const44   const llvm::APSInt &To() const {
45     return *second;
46   }
getConcreteValue() const47   const llvm::APSInt *getConcreteValue() const {
48     return &From() == &To() ? &From() : nullptr;
49   }
50 
Profile(llvm::FoldingSetNodeID & ID) const51   void Profile(llvm::FoldingSetNodeID &ID) const {
52     ID.AddPointer(&From());
53     ID.AddPointer(&To());
54   }
55 };
56 
57 
58 class RangeTrait : public llvm::ImutContainerInfo<Range> {
59 public:
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.
isLess(key_type_ref lhs,key_type_ref rhs)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.
73 class 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.
78 public:
79   typedef PrimRangeSet::Factory Factory;
80   typedef PrimRangeSet::iterator iterator;
81 
RangeSet(PrimRangeSet RS)82   RangeSet(PrimRangeSet RS) : ranges(RS) {}
83 
begin() const84   iterator begin() const { return ranges.begin(); }
end() const85   iterator end() const { return ranges.end(); }
86 
isEmpty() const87   bool isEmpty() const { return ranges.isEmpty(); }
88 
89   /// Construct a new RangeSet representing '{ [from, to] }'.
RangeSet(Factory & F,const llvm::APSInt & from,const llvm::APSInt & to)90   RangeSet(Factory &F, const llvm::APSInt &from, const llvm::APSInt &to)
91     : ranges(F.add(F.getEmptySet(), Range(from, to))) {}
92 
93   /// Profile - Generates a hash profile of this RangeSet for use
94   ///  by FoldingSet.
Profile(llvm::FoldingSetNodeID & ID) const95   void Profile(llvm::FoldingSetNodeID &ID) const { ranges.Profile(ID); }
96 
97   /// getConcreteValue - If a symbol is contrained to equal a specific integer
98   ///  constant then this method returns that value.  Otherwise, it returns
99   ///  NULL.
getConcreteValue() const100   const llvm::APSInt* getConcreteValue() const {
101     return ranges.isSingleton() ? ranges.begin()->getConcreteValue() : nullptr;
102   }
103 
104 private:
IntersectInRange(BasicValueFactory & BV,Factory & F,const llvm::APSInt & Lower,const llvm::APSInt & Upper,PrimRangeSet & newRanges,PrimRangeSet::iterator & i,PrimRangeSet::iterator & e) const105   void IntersectInRange(BasicValueFactory &BV, Factory &F,
106                         const llvm::APSInt &Lower,
107                         const llvm::APSInt &Upper,
108                         PrimRangeSet &newRanges,
109                         PrimRangeSet::iterator &i,
110                         PrimRangeSet::iterator &e) const {
111     // There are six cases for each range R in the set:
112     //   1. R is entirely before the intersection range.
113     //   2. R is entirely after the intersection range.
114     //   3. R contains the entire intersection range.
115     //   4. R starts before the intersection range and ends in the middle.
116     //   5. R starts in the middle of the intersection range and ends after it.
117     //   6. R is entirely contained in the intersection range.
118     // These correspond to each of the conditions below.
119     for (/* i = begin(), e = end() */; i != e; ++i) {
120       if (i->To() < Lower) {
121         continue;
122       }
123       if (i->From() > Upper) {
124         break;
125       }
126 
127       if (i->Includes(Lower)) {
128         if (i->Includes(Upper)) {
129           newRanges = F.add(newRanges, Range(BV.getValue(Lower),
130                                              BV.getValue(Upper)));
131           break;
132         } else
133           newRanges = F.add(newRanges, Range(BV.getValue(Lower), i->To()));
134       } else {
135         if (i->Includes(Upper)) {
136           newRanges = F.add(newRanges, Range(i->From(), BV.getValue(Upper)));
137           break;
138         } else
139           newRanges = F.add(newRanges, *i);
140       }
141     }
142   }
143 
getMinValue() const144   const llvm::APSInt &getMinValue() const {
145     assert(!isEmpty());
146     return ranges.begin()->From();
147   }
148 
pin(llvm::APSInt & Lower,llvm::APSInt & Upper) const149   bool pin(llvm::APSInt &Lower, llvm::APSInt &Upper) const {
150     // This function has nine cases, the cartesian product of range-testing
151     // both the upper and lower bounds against the symbol's type.
152     // Each case requires a different pinning operation.
153     // The function returns false if the described range is entirely outside
154     // the range of values for the associated symbol.
155     APSIntType Type(getMinValue());
156     APSIntType::RangeTestResultKind LowerTest = Type.testInRange(Lower, true);
157     APSIntType::RangeTestResultKind UpperTest = Type.testInRange(Upper, true);
158 
159     switch (LowerTest) {
160     case APSIntType::RTR_Below:
161       switch (UpperTest) {
162       case APSIntType::RTR_Below:
163         // The entire range is outside the symbol's set of possible values.
164         // If this is a conventionally-ordered range, the state is infeasible.
165         if (Lower < Upper)
166           return false;
167 
168         // However, if the range wraps around, it spans all possible values.
169         Lower = Type.getMinValue();
170         Upper = Type.getMaxValue();
171         break;
172       case APSIntType::RTR_Within:
173         // The range starts below what's possible but ends within it. Pin.
174         Lower = Type.getMinValue();
175         Type.apply(Upper);
176         break;
177       case APSIntType::RTR_Above:
178         // The range spans all possible values for the symbol. Pin.
179         Lower = Type.getMinValue();
180         Upper = Type.getMaxValue();
181         break;
182       }
183       break;
184     case APSIntType::RTR_Within:
185       switch (UpperTest) {
186       case APSIntType::RTR_Below:
187         // The range wraps around, but all lower values are not possible.
188         Type.apply(Lower);
189         Upper = Type.getMaxValue();
190         break;
191       case APSIntType::RTR_Within:
192         // The range may or may not wrap around, but both limits are valid.
193         Type.apply(Lower);
194         Type.apply(Upper);
195         break;
196       case APSIntType::RTR_Above:
197         // The range starts within what's possible but ends above it. Pin.
198         Type.apply(Lower);
199         Upper = Type.getMaxValue();
200         break;
201       }
202       break;
203     case APSIntType::RTR_Above:
204       switch (UpperTest) {
205       case APSIntType::RTR_Below:
206         // The range wraps but is outside the symbol's set of possible values.
207         return false;
208       case APSIntType::RTR_Within:
209         // The range starts above what's possible but ends within it (wrap).
210         Lower = Type.getMinValue();
211         Type.apply(Upper);
212         break;
213       case APSIntType::RTR_Above:
214         // The entire range is outside the symbol's set of possible values.
215         // If this is a conventionally-ordered range, the state is infeasible.
216         if (Lower < Upper)
217           return false;
218 
219         // However, if the range wraps around, it spans all possible values.
220         Lower = Type.getMinValue();
221         Upper = Type.getMaxValue();
222         break;
223       }
224       break;
225     }
226 
227     return true;
228   }
229 
230 public:
231   // Returns a set containing the values in the receiving set, intersected with
232   // the closed range [Lower, Upper]. Unlike the Range type, this range uses
233   // modular arithmetic, corresponding to the common treatment of C integer
234   // overflow. Thus, if the Lower bound is greater than the Upper bound, the
235   // range is taken to wrap around. This is equivalent to taking the
236   // intersection with the two ranges [Min, Upper] and [Lower, Max],
237   // or, alternatively, /removing/ all integers between Upper and Lower.
Intersect(BasicValueFactory & BV,Factory & F,llvm::APSInt Lower,llvm::APSInt Upper) const238   RangeSet Intersect(BasicValueFactory &BV, Factory &F,
239                      llvm::APSInt Lower, llvm::APSInt Upper) const {
240     if (!pin(Lower, Upper))
241       return F.getEmptySet();
242 
243     PrimRangeSet newRanges = F.getEmptySet();
244 
245     PrimRangeSet::iterator i = begin(), e = end();
246     if (Lower <= Upper)
247       IntersectInRange(BV, F, Lower, Upper, newRanges, i, e);
248     else {
249       // The order of the next two statements is important!
250       // IntersectInRange() does not reset the iteration state for i and e.
251       // Therefore, the lower range most be handled first.
252       IntersectInRange(BV, F, BV.getMinValue(Upper), Upper, newRanges, i, e);
253       IntersectInRange(BV, F, Lower, BV.getMaxValue(Lower), newRanges, i, e);
254     }
255 
256     return newRanges;
257   }
258 
print(raw_ostream & os) const259   void print(raw_ostream &os) const {
260     bool isFirst = true;
261     os << "{ ";
262     for (iterator i = begin(), e = end(); i != e; ++i) {
263       if (isFirst)
264         isFirst = false;
265       else
266         os << ", ";
267 
268       os << '[' << i->From().toString(10) << ", " << i->To().toString(10)
269          << ']';
270     }
271     os << " }";
272   }
273 
operator ==(const RangeSet & other) const274   bool operator==(const RangeSet &other) const {
275     return ranges == other.ranges;
276   }
277 };
278 } // end anonymous namespace
279 
280 REGISTER_TRAIT_WITH_PROGRAMSTATE(ConstraintRange,
281                                  CLANG_ENTO_PROGRAMSTATE_MAP(SymbolRef,
282                                                              RangeSet))
283 
284 namespace {
285 class RangeConstraintManager : public SimpleConstraintManager{
286   RangeSet GetRange(ProgramStateRef state, SymbolRef sym);
287 public:
RangeConstraintManager(SubEngine * subengine,SValBuilder & SVB)288   RangeConstraintManager(SubEngine *subengine, SValBuilder &SVB)
289     : SimpleConstraintManager(subengine, SVB) {}
290 
291   ProgramStateRef assumeSymNE(ProgramStateRef state, SymbolRef sym,
292                              const llvm::APSInt& Int,
293                              const llvm::APSInt& Adjustment) override;
294 
295   ProgramStateRef assumeSymEQ(ProgramStateRef state, SymbolRef sym,
296                              const llvm::APSInt& Int,
297                              const llvm::APSInt& Adjustment) override;
298 
299   ProgramStateRef assumeSymLT(ProgramStateRef state, SymbolRef sym,
300                              const llvm::APSInt& Int,
301                              const llvm::APSInt& Adjustment) override;
302 
303   ProgramStateRef assumeSymGT(ProgramStateRef state, SymbolRef sym,
304                              const llvm::APSInt& Int,
305                              const llvm::APSInt& Adjustment) override;
306 
307   ProgramStateRef assumeSymGE(ProgramStateRef state, SymbolRef sym,
308                              const llvm::APSInt& Int,
309                              const llvm::APSInt& Adjustment) override;
310 
311   ProgramStateRef assumeSymLE(ProgramStateRef state, SymbolRef sym,
312                              const llvm::APSInt& Int,
313                              const llvm::APSInt& Adjustment) override;
314 
315   const llvm::APSInt* getSymVal(ProgramStateRef St,
316                                 SymbolRef sym) const override;
317   ConditionTruthVal checkNull(ProgramStateRef State, SymbolRef Sym) override;
318 
319   ProgramStateRef removeDeadBindings(ProgramStateRef St,
320                                      SymbolReaper& SymReaper) override;
321 
322   void print(ProgramStateRef St, raw_ostream &Out,
323              const char* nl, const char *sep) override;
324 
325 private:
326   RangeSet::Factory F;
327 };
328 
329 } // end anonymous namespace
330 
331 std::unique_ptr<ConstraintManager>
CreateRangeConstraintManager(ProgramStateManager & StMgr,SubEngine * Eng)332 ento::CreateRangeConstraintManager(ProgramStateManager &StMgr, SubEngine *Eng) {
333   return llvm::make_unique<RangeConstraintManager>(Eng, StMgr.getSValBuilder());
334 }
335 
getSymVal(ProgramStateRef St,SymbolRef sym) const336 const llvm::APSInt* RangeConstraintManager::getSymVal(ProgramStateRef St,
337                                                       SymbolRef sym) const {
338   const ConstraintRangeTy::data_type *T = St->get<ConstraintRange>(sym);
339   return T ? T->getConcreteValue() : nullptr;
340 }
341 
checkNull(ProgramStateRef State,SymbolRef Sym)342 ConditionTruthVal RangeConstraintManager::checkNull(ProgramStateRef State,
343                                                     SymbolRef Sym) {
344   const RangeSet *Ranges = State->get<ConstraintRange>(Sym);
345 
346   // If we don't have any information about this symbol, it's underconstrained.
347   if (!Ranges)
348     return ConditionTruthVal();
349 
350   // If we have a concrete value, see if it's zero.
351   if (const llvm::APSInt *Value = Ranges->getConcreteValue())
352     return *Value == 0;
353 
354   BasicValueFactory &BV = getBasicVals();
355   APSIntType IntType = BV.getAPSIntType(Sym->getType());
356   llvm::APSInt Zero = IntType.getZeroValue();
357 
358   // Check if zero is in the set of possible values.
359   if (Ranges->Intersect(BV, F, Zero, Zero).isEmpty())
360     return false;
361 
362   // Zero is a possible value, but it is not the /only/ possible value.
363   return ConditionTruthVal();
364 }
365 
366 /// Scan all symbols referenced by the constraints. If the symbol is not alive
367 /// as marked in LSymbols, mark it as dead in DSymbols.
368 ProgramStateRef
removeDeadBindings(ProgramStateRef state,SymbolReaper & SymReaper)369 RangeConstraintManager::removeDeadBindings(ProgramStateRef state,
370                                            SymbolReaper& SymReaper) {
371 
372   ConstraintRangeTy CR = state->get<ConstraintRange>();
373   ConstraintRangeTy::Factory& CRFactory = state->get_context<ConstraintRange>();
374 
375   for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
376     SymbolRef sym = I.getKey();
377     if (SymReaper.maybeDead(sym))
378       CR = CRFactory.remove(CR, sym);
379   }
380 
381   return state->set<ConstraintRange>(CR);
382 }
383 
384 RangeSet
GetRange(ProgramStateRef state,SymbolRef sym)385 RangeConstraintManager::GetRange(ProgramStateRef state, SymbolRef sym) {
386   if (ConstraintRangeTy::data_type* V = state->get<ConstraintRange>(sym))
387     return *V;
388 
389   // Lazily generate a new RangeSet representing all possible values for the
390   // given symbol type.
391   BasicValueFactory &BV = getBasicVals();
392   QualType T = sym->getType();
393 
394   RangeSet Result(F, BV.getMinValue(T), BV.getMaxValue(T));
395 
396   // Special case: references are known to be non-zero.
397   if (T->isReferenceType()) {
398     APSIntType IntType = BV.getAPSIntType(T);
399     Result = Result.Intersect(BV, F, ++IntType.getZeroValue(),
400                                      --IntType.getZeroValue());
401   }
402 
403   return Result;
404 }
405 
406 //===------------------------------------------------------------------------===
407 // assumeSymX methods: public interface for RangeConstraintManager.
408 //===------------------------------------------------------------------------===/
409 
410 // The syntax for ranges below is mathematical, using [x, y] for closed ranges
411 // and (x, y) for open ranges. These ranges are modular, corresponding with
412 // a common treatment of C integer overflow. This means that these methods
413 // do not have to worry about overflow; RangeSet::Intersect can handle such a
414 // "wraparound" range.
415 // As an example, the range [UINT_MAX-1, 3) contains five values: UINT_MAX-1,
416 // UINT_MAX, 0, 1, and 2.
417 
418 ProgramStateRef
assumeSymNE(ProgramStateRef St,SymbolRef Sym,const llvm::APSInt & Int,const llvm::APSInt & Adjustment)419 RangeConstraintManager::assumeSymNE(ProgramStateRef St, SymbolRef Sym,
420                                     const llvm::APSInt &Int,
421                                     const llvm::APSInt &Adjustment) {
422   // Before we do any real work, see if the value can even show up.
423   APSIntType AdjustmentType(Adjustment);
424   if (AdjustmentType.testInRange(Int, true) != APSIntType::RTR_Within)
425     return St;
426 
427   llvm::APSInt Lower = AdjustmentType.convert(Int) - Adjustment;
428   llvm::APSInt Upper = Lower;
429   --Lower;
430   ++Upper;
431 
432   // [Int-Adjustment+1, Int-Adjustment-1]
433   // Notice that the lower bound is greater than the upper bound.
434   RangeSet New = GetRange(St, Sym).Intersect(getBasicVals(), F, Upper, Lower);
435   return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
436 }
437 
438 ProgramStateRef
assumeSymEQ(ProgramStateRef St,SymbolRef Sym,const llvm::APSInt & Int,const llvm::APSInt & Adjustment)439 RangeConstraintManager::assumeSymEQ(ProgramStateRef St, SymbolRef Sym,
440                                     const llvm::APSInt &Int,
441                                     const llvm::APSInt &Adjustment) {
442   // Before we do any real work, see if the value can even show up.
443   APSIntType AdjustmentType(Adjustment);
444   if (AdjustmentType.testInRange(Int, true) != APSIntType::RTR_Within)
445     return nullptr;
446 
447   // [Int-Adjustment, Int-Adjustment]
448   llvm::APSInt AdjInt = AdjustmentType.convert(Int) - Adjustment;
449   RangeSet New = GetRange(St, Sym).Intersect(getBasicVals(), F, AdjInt, AdjInt);
450   return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
451 }
452 
453 ProgramStateRef
assumeSymLT(ProgramStateRef St,SymbolRef Sym,const llvm::APSInt & Int,const llvm::APSInt & Adjustment)454 RangeConstraintManager::assumeSymLT(ProgramStateRef St, SymbolRef Sym,
455                                     const llvm::APSInt &Int,
456                                     const llvm::APSInt &Adjustment) {
457   // Before we do any real work, see if the value can even show up.
458   APSIntType AdjustmentType(Adjustment);
459   switch (AdjustmentType.testInRange(Int, true)) {
460   case APSIntType::RTR_Below:
461     return nullptr;
462   case APSIntType::RTR_Within:
463     break;
464   case APSIntType::RTR_Above:
465     return St;
466   }
467 
468   // Special case for Int == Min. This is always false.
469   llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
470   llvm::APSInt Min = AdjustmentType.getMinValue();
471   if (ComparisonVal == Min)
472     return nullptr;
473 
474   llvm::APSInt Lower = Min-Adjustment;
475   llvm::APSInt Upper = ComparisonVal-Adjustment;
476   --Upper;
477 
478   RangeSet New = GetRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
479   return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
480 }
481 
482 ProgramStateRef
assumeSymGT(ProgramStateRef St,SymbolRef Sym,const llvm::APSInt & Int,const llvm::APSInt & Adjustment)483 RangeConstraintManager::assumeSymGT(ProgramStateRef St, SymbolRef Sym,
484                                     const llvm::APSInt &Int,
485                                     const llvm::APSInt &Adjustment) {
486   // Before we do any real work, see if the value can even show up.
487   APSIntType AdjustmentType(Adjustment);
488   switch (AdjustmentType.testInRange(Int, true)) {
489   case APSIntType::RTR_Below:
490     return St;
491   case APSIntType::RTR_Within:
492     break;
493   case APSIntType::RTR_Above:
494     return nullptr;
495   }
496 
497   // Special case for Int == Max. This is always false.
498   llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
499   llvm::APSInt Max = AdjustmentType.getMaxValue();
500   if (ComparisonVal == Max)
501     return nullptr;
502 
503   llvm::APSInt Lower = ComparisonVal-Adjustment;
504   llvm::APSInt Upper = Max-Adjustment;
505   ++Lower;
506 
507   RangeSet New = GetRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
508   return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
509 }
510 
511 ProgramStateRef
assumeSymGE(ProgramStateRef St,SymbolRef Sym,const llvm::APSInt & Int,const llvm::APSInt & Adjustment)512 RangeConstraintManager::assumeSymGE(ProgramStateRef St, SymbolRef Sym,
513                                     const llvm::APSInt &Int,
514                                     const llvm::APSInt &Adjustment) {
515   // Before we do any real work, see if the value can even show up.
516   APSIntType AdjustmentType(Adjustment);
517   switch (AdjustmentType.testInRange(Int, true)) {
518   case APSIntType::RTR_Below:
519     return St;
520   case APSIntType::RTR_Within:
521     break;
522   case APSIntType::RTR_Above:
523     return nullptr;
524   }
525 
526   // Special case for Int == Min. This is always feasible.
527   llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
528   llvm::APSInt Min = AdjustmentType.getMinValue();
529   if (ComparisonVal == Min)
530     return St;
531 
532   llvm::APSInt Max = AdjustmentType.getMaxValue();
533   llvm::APSInt Lower = ComparisonVal-Adjustment;
534   llvm::APSInt Upper = Max-Adjustment;
535 
536   RangeSet New = GetRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
537   return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
538 }
539 
540 ProgramStateRef
assumeSymLE(ProgramStateRef St,SymbolRef Sym,const llvm::APSInt & Int,const llvm::APSInt & Adjustment)541 RangeConstraintManager::assumeSymLE(ProgramStateRef St, SymbolRef Sym,
542                                     const llvm::APSInt &Int,
543                                     const llvm::APSInt &Adjustment) {
544   // Before we do any real work, see if the value can even show up.
545   APSIntType AdjustmentType(Adjustment);
546   switch (AdjustmentType.testInRange(Int, true)) {
547   case APSIntType::RTR_Below:
548     return nullptr;
549   case APSIntType::RTR_Within:
550     break;
551   case APSIntType::RTR_Above:
552     return St;
553   }
554 
555   // Special case for Int == Max. This is always feasible.
556   llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
557   llvm::APSInt Max = AdjustmentType.getMaxValue();
558   if (ComparisonVal == Max)
559     return St;
560 
561   llvm::APSInt Min = AdjustmentType.getMinValue();
562   llvm::APSInt Lower = Min-Adjustment;
563   llvm::APSInt Upper = ComparisonVal-Adjustment;
564 
565   RangeSet New = GetRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
566   return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
567 }
568 
569 //===------------------------------------------------------------------------===
570 // Pretty-printing.
571 //===------------------------------------------------------------------------===/
572 
print(ProgramStateRef St,raw_ostream & Out,const char * nl,const char * sep)573 void RangeConstraintManager::print(ProgramStateRef St, raw_ostream &Out,
574                                    const char* nl, const char *sep) {
575 
576   ConstraintRangeTy Ranges = St->get<ConstraintRange>();
577 
578   if (Ranges.isEmpty()) {
579     Out << nl << sep << "Ranges are empty." << nl;
580     return;
581   }
582 
583   Out << nl << sep << "Ranges of symbol values:";
584   for (ConstraintRangeTy::iterator I=Ranges.begin(), E=Ranges.end(); I!=E; ++I){
585     Out << nl << ' ' << I.getKey() << " : ";
586     I.getData().print(Out);
587   }
588   Out << nl;
589 }
590