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