RangedConstraintManager.h revision 344779 
1//== RangedConstraintManager.h ----------------------------------*- 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//  Ranged constraint manager, built on SimpleConstraintManager.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_LIB_STATICANALYZER_CORE_RANGEDCONSTRAINTMANAGER_H
15#define LLVM_CLANG_LIB_STATICANALYZER_CORE_RANGEDCONSTRAINTMANAGER_H
16
17#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
18#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
19#include "clang/StaticAnalyzer/Core/PathSensitive/SimpleConstraintManager.h"
20
21namespace clang {
22
23namespace ento {
24
25/// A Range represents the closed range [from, to].  The caller must
26/// guarantee that from <= to.  Note that Range is immutable, so as not
27/// to subvert RangeSet's immutability.
28class Range : public std::pair<const llvm::APSInt *, const llvm::APSInt *> {
29public:
30  Range(const llvm::APSInt &from, const llvm::APSInt &to)
31      : std::pair<const llvm::APSInt *, const llvm::APSInt *>(&from, &to) {
32    assert(from <= to);
33  }
34  bool Includes(const llvm::APSInt &v) const {
35    return *first <= v && v <= *second;
36  }
37  const llvm::APSInt &From() const { return *first; }
38  const llvm::APSInt &To() const { return *second; }
39  const llvm::APSInt *getConcreteValue() const {
40    return &From() == &To() ? &From() : nullptr;
41  }
42
43  void Profile(llvm::FoldingSetNodeID &ID) const {
44    ID.AddPointer(&From());
45    ID.AddPointer(&To());
46  }
47};
48
49class RangeTrait : public llvm::ImutContainerInfo<Range> {
50public:
51  // When comparing if one Range is less than another, we should compare
52  // the actual APSInt values instead of their pointers.  This keeps the order
53  // consistent (instead of comparing by pointer values) and can potentially
54  // be used to speed up some of the operations in RangeSet.
55  static inline bool isLess(key_type_ref lhs, key_type_ref rhs) {
56    return *lhs.first < *rhs.first ||
57           (!(*rhs.first < *lhs.first) && *lhs.second < *rhs.second);
58  }
59};
60
61/// RangeSet contains a set of ranges. If the set is empty, then
62///  there the value of a symbol is overly constrained and there are no
63///  possible values for that symbol.
64class RangeSet {
65  typedef llvm::ImmutableSet<Range, RangeTrait> PrimRangeSet;
66  PrimRangeSet ranges; // no need to make const, since it is an
67                       // ImmutableSet - this allows default operator=
68                       // to work.
69public:
70  typedef PrimRangeSet::Factory Factory;
71  typedef PrimRangeSet::iterator iterator;
72
73  RangeSet(PrimRangeSet RS) : ranges(RS) {}
74
75  /// Create a new set with all ranges of this set and RS.
76  /// Possible intersections are not checked here.
77  RangeSet addRange(Factory &F, const RangeSet &RS) {
78    PrimRangeSet Ranges(RS.ranges);
79    for (const auto &range : ranges)
80      Ranges = F.add(Ranges, range);
81    return RangeSet(Ranges);
82  }
83
84  iterator begin() const { return ranges.begin(); }
85  iterator end() const { return ranges.end(); }
86
87  bool isEmpty() const { return ranges.isEmpty(); }
88
89  /// Construct a new RangeSet representing '{ [from, 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.
95  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.
100  const llvm::APSInt *getConcreteValue() const {
101    return ranges.isSingleton() ? ranges.begin()->getConcreteValue() : nullptr;
102  }
103
104private:
105  void IntersectInRange(BasicValueFactory &BV, Factory &F,
106                        const llvm::APSInt &Lower, const llvm::APSInt &Upper,
107                        PrimRangeSet &newRanges, PrimRangeSet::iterator &i,
108                        PrimRangeSet::iterator &e) const;
109
110  const llvm::APSInt &getMinValue() const;
111
112  bool pin(llvm::APSInt &Lower, llvm::APSInt &Upper) const;
113
114public:
115  RangeSet Intersect(BasicValueFactory &BV, Factory &F, llvm::APSInt Lower,
116                     llvm::APSInt Upper) const;
117
118  RangeSet Negate(BasicValueFactory &BV, Factory &F) const;
119
120  void print(raw_ostream &os) const;
121
122  bool operator==(const RangeSet &other) const {
123    return ranges == other.ranges;
124  }
125};
126
127
128class ConstraintRange {};
129using ConstraintRangeTy = llvm::ImmutableMap<SymbolRef, RangeSet>;
130
131template <>
132struct ProgramStateTrait<ConstraintRange>
133  : public ProgramStatePartialTrait<ConstraintRangeTy> {
134  static void *GDMIndex();
135};
136
137
138class RangedConstraintManager : public SimpleConstraintManager {
139public:
140  RangedConstraintManager(SubEngine *SE, SValBuilder &SB)
141      : SimpleConstraintManager(SE, SB) {}
142
143  ~RangedConstraintManager() override;
144
145  //===------------------------------------------------------------------===//
146  // Implementation for interface from SimpleConstraintManager.
147  //===------------------------------------------------------------------===//
148
149  ProgramStateRef assumeSym(ProgramStateRef State, SymbolRef Sym,
150                            bool Assumption) override;
151
152  ProgramStateRef assumeSymInclusiveRange(ProgramStateRef State, SymbolRef Sym,
153                                          const llvm::APSInt &From,
154                                          const llvm::APSInt &To,
155                                          bool InRange) override;
156
157  ProgramStateRef assumeSymUnsupported(ProgramStateRef State, SymbolRef Sym,
158                                       bool Assumption) override;
159
160protected:
161  /// Assume a constraint between a symbolic expression and a concrete integer.
162  virtual ProgramStateRef assumeSymRel(ProgramStateRef State, SymbolRef Sym,
163                               BinaryOperator::Opcode op,
164                               const llvm::APSInt &Int);
165
166  //===------------------------------------------------------------------===//
167  // Interface that subclasses must implement.
168  //===------------------------------------------------------------------===//
169
170  // Each of these is of the form "$Sym+Adj <> V", where "<>" is the comparison
171  // operation for the method being invoked.
172
173  virtual ProgramStateRef assumeSymNE(ProgramStateRef State, SymbolRef Sym,
174                                      const llvm::APSInt &V,
175                                      const llvm::APSInt &Adjustment) = 0;
176
177  virtual ProgramStateRef assumeSymEQ(ProgramStateRef State, SymbolRef Sym,
178                                      const llvm::APSInt &V,
179                                      const llvm::APSInt &Adjustment) = 0;
180
181  virtual ProgramStateRef assumeSymLT(ProgramStateRef State, SymbolRef Sym,
182                                      const llvm::APSInt &V,
183                                      const llvm::APSInt &Adjustment) = 0;
184
185  virtual ProgramStateRef assumeSymGT(ProgramStateRef State, SymbolRef Sym,
186                                      const llvm::APSInt &V,
187                                      const llvm::APSInt &Adjustment) = 0;
188
189  virtual ProgramStateRef assumeSymLE(ProgramStateRef State, SymbolRef Sym,
190                                      const llvm::APSInt &V,
191                                      const llvm::APSInt &Adjustment) = 0;
192
193  virtual ProgramStateRef assumeSymGE(ProgramStateRef State, SymbolRef Sym,
194                                      const llvm::APSInt &V,
195                                      const llvm::APSInt &Adjustment) = 0;
196
197  virtual ProgramStateRef assumeSymWithinInclusiveRange(
198      ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
199      const llvm::APSInt &To, const llvm::APSInt &Adjustment) = 0;
200
201  virtual ProgramStateRef assumeSymOutsideInclusiveRange(
202      ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
203      const llvm::APSInt &To, const llvm::APSInt &Adjustment) = 0;
204
205  //===------------------------------------------------------------------===//
206  // Internal implementation.
207  //===------------------------------------------------------------------===//
208private:
209  static void computeAdjustment(SymbolRef &Sym, llvm::APSInt &Adjustment);
210};
211
212} // end GR namespace
213
214} // end clang namespace
215
216#endif
217