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