Store.h revision 4411b423e91da0a2c879b70c0222aeba35f72044 
1//== Store.h - Interface for maps from Locations to Values ------*- 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 defined the types Store and StoreManager.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_GR_STORE_H
15#define LLVM_CLANG_GR_STORE_H
16
17#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
18#include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"
19#include "clang/StaticAnalyzer/Core/PathSensitive/StoreRef.h"
20#include "llvm/ADT/DenseSet.h"
21#include "llvm/ADT/Optional.h"
22
23namespace clang {
24
25class Stmt;
26class Expr;
27class ObjCIvarDecl;
28class CXXBasePath;
29class StackFrameContext;
30
31namespace ento {
32
33class CallEvent;
34class ProgramState;
35class ProgramStateManager;
36class ScanReachableSymbols;
37
38typedef llvm::DenseSet<SymbolRef> InvalidatedSymbols;
39
40class StoreManager {
41protected:
42  SValBuilder &svalBuilder;
43  ProgramStateManager &StateMgr;
44
45  /// MRMgr - Manages region objects associated with this StoreManager.
46  MemRegionManager &MRMgr;
47  ASTContext &Ctx;
48
49  StoreManager(ProgramStateManager &stateMgr);
50
51public:
52  virtual ~StoreManager() {}
53
54  /// Return the value bound to specified location in a given state.
55  /// \param[in] store The analysis state.
56  /// \param[in] loc The symbolic memory location.
57  /// \param[in] T An optional type that provides a hint indicating the
58  ///   expected type of the returned value.  This is used if the value is
59  ///   lazily computed.
60  /// \return The value bound to the location \c loc.
61  virtual SVal getBinding(Store store, Loc loc, QualType T = QualType()) = 0;
62
63  /// Return a state with the specified value bound to the given location.
64  /// \param[in] store The analysis state.
65  /// \param[in] loc The symbolic memory location.
66  /// \param[in] val The value to bind to location \c loc.
67  /// \return A pointer to a ProgramState object that contains the same
68  ///   bindings as \c state with the addition of having the value specified
69  ///   by \c val bound to the location given for \c loc.
70  virtual StoreRef Bind(Store store, Loc loc, SVal val) = 0;
71
72  virtual StoreRef BindDefault(Store store, const MemRegion *R, SVal V);
73
74  /// \brief Create a new store with the specified binding removed.
75  /// \param ST the original store, that is the basis for the new store.
76  /// \param L the location whose binding should be removed.
77  virtual StoreRef killBinding(Store ST, Loc L) = 0;
78
79  /// \brief Create a new store that binds a value to a compound literal.
80  ///
81  /// \param ST The original store whose bindings are the basis for the new
82  ///        store.
83  ///
84  /// \param CL The compound literal to bind (the binding key).
85  ///
86  /// \param LC The LocationContext for the binding.
87  ///
88  /// \param V The value to bind to the compound literal.
89  virtual StoreRef bindCompoundLiteral(Store ST,
90                                       const CompoundLiteralExpr *CL,
91                                       const LocationContext *LC,
92                                       SVal V) = 0;
93
94  /// getInitialStore - Returns the initial "empty" store representing the
95  ///  value bindings upon entry to an analyzed function.
96  virtual StoreRef getInitialStore(const LocationContext *InitLoc) = 0;
97
98  /// getRegionManager - Returns the internal RegionManager object that is
99  ///  used to query and manipulate MemRegion objects.
100  MemRegionManager& getRegionManager() { return MRMgr; }
101
102  virtual Loc getLValueVar(const VarDecl *VD, const LocationContext *LC) {
103    return svalBuilder.makeLoc(MRMgr.getVarRegion(VD, LC));
104  }
105
106  Loc getLValueCompoundLiteral(const CompoundLiteralExpr *CL,
107                               const LocationContext *LC) {
108    return loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC));
109  }
110
111  virtual SVal getLValueIvar(const ObjCIvarDecl *decl, SVal base);
112
113  virtual SVal getLValueField(const FieldDecl *D, SVal Base) {
114    return getLValueFieldOrIvar(D, Base);
115  }
116
117  virtual SVal getLValueElement(QualType elementType, NonLoc offset, SVal Base);
118
119  // FIXME: This should soon be eliminated altogether; clients should deal with
120  // region extents directly.
121  virtual DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state,
122                                                 const MemRegion *region,
123                                                 QualType EleTy) {
124    return UnknownVal();
125  }
126
127  /// ArrayToPointer - Used by ExprEngine::VistCast to handle implicit
128  ///  conversions between arrays and pointers.
129  virtual SVal ArrayToPointer(Loc Array) = 0;
130
131  /// Evaluates a chain of derived-to-base casts through the path specified in
132  /// \p Cast.
133  SVal evalDerivedToBase(SVal Derived, const CastExpr *Cast);
134
135  /// Evaluates a chain of derived-to-base casts through the specified path.
136  SVal evalDerivedToBase(SVal Derived, const CXXBasePath &CastPath);
137
138  /// Evaluates a derived-to-base cast through a single level of derivation.
139  SVal evalDerivedToBase(SVal Derived, QualType DerivedPtrType,
140                         bool IsVirtual);
141
142  /// \brief Evaluates C++ dynamic_cast cast.
143  /// The callback may result in the following 3 scenarios:
144  ///  - Successful cast (ex: derived is subclass of base).
145  ///  - Failed cast (ex: derived is definitely not a subclass of base).
146  ///  - We don't know (base is a symbolic region and we don't have
147  ///    enough info to determine if the cast will succeed at run time).
148  /// The function returns an SVal representing the derived class; it's
149  /// valid only if Failed flag is set to false.
150  SVal evalDynamicCast(SVal Base, QualType DerivedPtrType, bool &Failed);
151
152  const ElementRegion *GetElementZeroRegion(const MemRegion *R, QualType T);
153
154  /// castRegion - Used by ExprEngine::VisitCast to handle casts from
155  ///  a MemRegion* to a specific location type.  'R' is the region being
156  ///  casted and 'CastToTy' the result type of the cast.
157  const MemRegion *castRegion(const MemRegion *region, QualType CastToTy);
158
159  virtual StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
160                                      SymbolReaper& SymReaper) = 0;
161
162  virtual bool includedInBindings(Store store,
163                                  const MemRegion *region) const = 0;
164
165  /// If the StoreManager supports it, increment the reference count of
166  /// the specified Store object.
167  virtual void incrementReferenceCount(Store store) {}
168
169  /// If the StoreManager supports it, decrement the reference count of
170  /// the specified Store object.  If the reference count hits 0, the memory
171  /// associated with the object is recycled.
172  virtual void decrementReferenceCount(Store store) {}
173
174  typedef SmallVector<const MemRegion *, 8> InvalidatedRegions;
175
176  /// invalidateRegions - Clears out the specified regions from the store,
177  ///  marking their values as unknown. Depending on the store, this may also
178  ///  invalidate additional regions that may have changed based on accessing
179  ///  the given regions. Optionally, invalidates non-static globals as well.
180  /// \param[in] store The initial store
181  /// \param[in] Regions The regions to invalidate.
182  /// \param[in] E The current statement being evaluated. Used to conjure
183  ///   symbols to mark the values of invalidated regions.
184  /// \param[in] Count The current block count. Used to conjure
185  ///   symbols to mark the values of invalidated regions.
186  /// \param[in,out] IS A set to fill with any symbols that are no longer
187  ///   accessible. Pass \c NULL if this information will not be used.
188  /// \param[in] Call The call expression which will be used to determine which
189  ///   globals should get invalidated.
190  /// \param[in,out] Invalidated A vector to fill with any regions being
191  ///   invalidated. This should include any regions explicitly invalidated
192  ///   even if they do not currently have bindings. Pass \c NULL if this
193  ///   information will not be used.
194  virtual StoreRef invalidateRegions(Store store,
195                                     ArrayRef<const MemRegion *> Regions,
196                                     const Expr *E, unsigned Count,
197                                     const LocationContext *LCtx,
198                                     InvalidatedSymbols &IS,
199                                     const CallEvent *Call,
200                                     InvalidatedRegions *Invalidated) = 0;
201
202  /// enterStackFrame - Let the StoreManager to do something when execution
203  /// engine is about to execute into a callee.
204  StoreRef enterStackFrame(Store store,
205                           const CallEvent &Call,
206                           const StackFrameContext *CalleeCtx);
207
208  /// Finds the transitive closure of symbols within the given region.
209  ///
210  /// Returns false if the visitor aborted the scan.
211  virtual bool scanReachableSymbols(Store S, const MemRegion *R,
212                                    ScanReachableSymbols &Visitor) = 0;
213
214  virtual void print(Store store, raw_ostream &Out,
215                     const char* nl, const char *sep) = 0;
216
217  class BindingsHandler {
218  public:
219    virtual ~BindingsHandler();
220    virtual bool HandleBinding(StoreManager& SMgr, Store store,
221                               const MemRegion *region, SVal val) = 0;
222  };
223
224  class FindUniqueBinding :
225  public BindingsHandler {
226    SymbolRef Sym;
227    const MemRegion* Binding;
228    bool First;
229
230  public:
231    FindUniqueBinding(SymbolRef sym) : Sym(sym), Binding(0), First(true) {}
232
233    bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R,
234                       SVal val);
235    operator bool() { return First && Binding; }
236    const MemRegion *getRegion() { return Binding; }
237  };
238
239  /// iterBindings - Iterate over the bindings in the Store.
240  virtual void iterBindings(Store store, BindingsHandler& f) = 0;
241
242protected:
243  const MemRegion *MakeElementRegion(const MemRegion *baseRegion,
244                                     QualType pointeeTy, uint64_t index = 0);
245
246  /// CastRetrievedVal - Used by subclasses of StoreManager to implement
247  ///  implicit casts that arise from loads from regions that are reinterpreted
248  ///  as another region.
249  SVal CastRetrievedVal(SVal val, const TypedValueRegion *region,
250                        QualType castTy, bool performTestOnly = true);
251
252private:
253  SVal getLValueFieldOrIvar(const Decl *decl, SVal base);
254};
255
256
257inline StoreRef::StoreRef(Store store, StoreManager & smgr)
258  : store(store), mgr(smgr) {
259  if (store)
260    mgr.incrementReferenceCount(store);
261}
262
263inline StoreRef::StoreRef(const StoreRef &sr)
264  : store(sr.store), mgr(sr.mgr)
265{
266  if (store)
267    mgr.incrementReferenceCount(store);
268}
269
270inline StoreRef::~StoreRef() {
271  if (store)
272    mgr.decrementReferenceCount(store);
273}
274
275inline StoreRef &StoreRef::operator=(StoreRef const &newStore) {
276  assert(&newStore.mgr == &mgr);
277  if (store != newStore.store) {
278    mgr.incrementReferenceCount(newStore.store);
279    mgr.decrementReferenceCount(store);
280    store = newStore.getStore();
281  }
282  return *this;
283}
284
285// FIXME: Do we need to pass ProgramStateManager anymore?
286StoreManager *CreateRegionStoreManager(ProgramStateManager& StMgr);
287StoreManager *CreateFieldsOnlyRegionStoreManager(ProgramStateManager& StMgr);
288
289} // end GR namespace
290
291} // end clang namespace
292
293#endif
294