Store.h revision 77a4d5687c2cb3199c689892c9d040a94ff270af 
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 "llvm/ADT/DenseSet.h"
20#include "llvm/ADT/Optional.h"
21
22namespace clang {
23
24class Stmt;
25class Expr;
26class ObjCIvarDecl;
27class StackFrameContext;
28
29namespace ento {
30
31/// Store - This opaque type encapsulates an immutable mapping from
32///  locations to values.  At a high-level, it represents the symbolic
33///  memory model.  Different subclasses of StoreManager may choose
34///  different types to represent the locations and values.
35typedef const void* Store;
36
37class GRState;
38class GRStateManager;
39class SubRegionMap;
40class StoreManager;
41
42class StoreRef {
43  Store store;
44  StoreManager &mgr;
45public:
46  StoreRef(Store, StoreManager &);
47  StoreRef(const StoreRef &);
48  StoreRef &operator=(StoreRef const &);
49
50  bool operator==(const StoreRef &x) const {
51    assert(&mgr == &x.mgr);
52    return x.store == store;
53  }
54  bool operator!=(const StoreRef &x) const { return !operator==(x); }
55
56  ~StoreRef();
57
58  Store getStore() const { return store; }
59};
60
61class StoreManager {
62protected:
63  SValBuilder &svalBuilder;
64  GRStateManager &StateMgr;
65
66  /// MRMgr - Manages region objects associated with this StoreManager.
67  MemRegionManager &MRMgr;
68  ASTContext &Ctx;
69
70  StoreManager(GRStateManager &stateMgr);
71
72public:
73  virtual ~StoreManager() {}
74
75  /// Return the value bound to specified location in a given state.
76  /// \param[in] state The analysis state.
77  /// \param[in] loc The symbolic memory location.
78  /// \param[in] T An optional type that provides a hint indicating the
79  ///   expected type of the returned value.  This is used if the value is
80  ///   lazily computed.
81  /// \return The value bound to the location \c loc.
82  virtual SVal Retrieve(Store store, Loc loc, QualType T = QualType()) = 0;
83
84  /// Return a state with the specified value bound to the given location.
85  /// \param[in] state The analysis state.
86  /// \param[in] loc The symbolic memory location.
87  /// \param[in] val The value to bind to location \c loc.
88  /// \return A pointer to a GRState object that contains the same bindings as
89  ///   \c state with the addition of having the value specified by \c val bound
90  ///   to the location given for \c loc.
91  virtual StoreRef Bind(Store store, Loc loc, SVal val) = 0;
92
93  virtual StoreRef BindDefault(Store store, const MemRegion *R, SVal V);
94  virtual StoreRef Remove(Store St, Loc L) = 0;
95
96  /// BindCompoundLiteral - Return the store that has the bindings currently
97  ///  in 'store' plus the bindings for the CompoundLiteral.  'R' is the region
98  ///  for the compound literal and 'BegInit' and 'EndInit' represent an
99  ///  array of initializer values.
100  virtual StoreRef BindCompoundLiteral(Store store,
101                                       const CompoundLiteralExpr* cl,
102                                       const LocationContext *LC, SVal v) = 0;
103
104  /// getInitialStore - Returns the initial "empty" store representing the
105  ///  value bindings upon entry to an analyzed function.
106  virtual StoreRef getInitialStore(const LocationContext *InitLoc) = 0;
107
108  /// getRegionManager - Returns the internal RegionManager object that is
109  ///  used to query and manipulate MemRegion objects.
110  MemRegionManager& getRegionManager() { return MRMgr; }
111
112  /// getSubRegionMap - Returns an opaque map object that clients can query
113  ///  to get the subregions of a given MemRegion object.  It is the
114  //   caller's responsibility to 'delete' the returned map.
115  virtual SubRegionMap *getSubRegionMap(Store store) = 0;
116
117  virtual Loc getLValueVar(const VarDecl *VD, const LocationContext *LC) {
118    return svalBuilder.makeLoc(MRMgr.getVarRegion(VD, LC));
119  }
120
121  virtual Loc getLValueString(const StringLiteral* S) {
122    return svalBuilder.makeLoc(MRMgr.getStringRegion(S));
123  }
124
125  Loc getLValueCompoundLiteral(const CompoundLiteralExpr* CL,
126                               const LocationContext *LC) {
127    return loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC));
128  }
129
130  virtual SVal getLValueIvar(const ObjCIvarDecl* decl, SVal base) {
131    return getLValueFieldOrIvar(decl, base);
132  }
133
134  virtual SVal getLValueField(const FieldDecl* D, SVal Base) {
135    return getLValueFieldOrIvar(D, Base);
136  }
137
138  virtual SVal getLValueElement(QualType elementType, NonLoc offset, SVal Base);
139
140  // FIXME: This should soon be eliminated altogether; clients should deal with
141  // region extents directly.
142  virtual DefinedOrUnknownSVal getSizeInElements(const GRState *state,
143                                                 const MemRegion *region,
144                                                 QualType EleTy) {
145    return UnknownVal();
146  }
147
148  /// ArrayToPointer - Used by ExprEngine::VistCast to handle implicit
149  ///  conversions between arrays and pointers.
150  virtual SVal ArrayToPointer(Loc Array) = 0;
151
152  /// Evaluates DerivedToBase casts.
153  virtual SVal evalDerivedToBase(SVal derived, QualType basePtrType) {
154    return UnknownVal();
155  }
156
157  class CastResult {
158    const GRState *state;
159    const MemRegion *region;
160  public:
161    const GRState *getState() const { return state; }
162    const MemRegion* getRegion() const { return region; }
163    CastResult(const GRState *s, const MemRegion* r = 0) : state(s), region(r){}
164  };
165
166  const ElementRegion *GetElementZeroRegion(const MemRegion *R, QualType T);
167
168  /// castRegion - Used by ExprEngine::VisitCast to handle casts from
169  ///  a MemRegion* to a specific location type.  'R' is the region being
170  ///  casted and 'CastToTy' the result type of the cast.
171  const MemRegion *castRegion(const MemRegion *region, QualType CastToTy);
172
173  virtual StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
174                                      SymbolReaper& SymReaper,
175                      llvm::SmallVectorImpl<const MemRegion*>& RegionRoots) = 0;
176
177  virtual StoreRef BindDecl(Store store, const VarRegion *VR, SVal initVal) = 0;
178
179  virtual StoreRef BindDeclWithNoInit(Store store, const VarRegion *VR) = 0;
180
181  /// If the StoreManager supports it, increment the reference count of
182  /// the specified Store object.
183  virtual void incrementReferenceCount(Store store) {}
184
185  /// If the StoreManager supports it, decrement the reference count of
186  /// the specified Store object.  If the reference count hits 0, the memory
187  /// associated with the object is recycled.
188  virtual void decrementReferenceCount(Store store) {}
189
190  typedef llvm::DenseSet<SymbolRef> InvalidatedSymbols;
191  typedef llvm::SmallVector<const MemRegion *, 8> InvalidatedRegions;
192
193  /// invalidateRegions - Clears out the specified regions from the store,
194  ///  marking their values as unknown. Depending on the store, this may also
195  ///  invalidate additional regions that may have changed based on accessing
196  ///  the given regions. Optionally, invalidates non-static globals as well.
197  /// \param[in] store The initial store
198  /// \param[in] Begin A pointer to the first region to invalidate.
199  /// \param[in] End A pointer just past the last region to invalidate.
200  /// \param[in] E The current statement being evaluated. Used to conjure
201  ///   symbols to mark the values of invalidated regions.
202  /// \param[in] Count The current block count. Used to conjure
203  ///   symbols to mark the values of invalidated regions.
204  /// \param[in,out] IS A set to fill with any symbols that are no longer
205  ///   accessible. Pass \c NULL if this information will not be used.
206  /// \param[in] invalidateGlobals If \c true, any non-static global regions
207  ///   are invalidated as well.
208  /// \param[in,out] Regions A vector to fill with any regions being
209  ///   invalidated. This should include any regions explicitly invalidated
210  ///   even if they do not currently have bindings. Pass \c NULL if this
211  ///   information will not be used.
212  virtual StoreRef invalidateRegions(Store store,
213                                     const MemRegion * const *Begin,
214                                     const MemRegion * const *End,
215                                     const Expr *E, unsigned Count,
216                                     InvalidatedSymbols *IS,
217                                     bool invalidateGlobals,
218                                     InvalidatedRegions *Regions) = 0;
219
220  /// enterStackFrame - Let the StoreManager to do something when execution
221  /// engine is about to execute into a callee.
222  virtual StoreRef enterStackFrame(const GRState *state,
223                                   const StackFrameContext *frame);
224
225  virtual void print(Store store, llvm::raw_ostream& Out,
226                     const char* nl, const char *sep) = 0;
227
228  class BindingsHandler {
229  public:
230    virtual ~BindingsHandler();
231    virtual bool HandleBinding(StoreManager& SMgr, Store store,
232                               const MemRegion *region, SVal val) = 0;
233  };
234
235  /// iterBindings - Iterate over the bindings in the Store.
236  virtual void iterBindings(Store store, BindingsHandler& f) = 0;
237
238protected:
239  const MemRegion *MakeElementRegion(const MemRegion *baseRegion,
240                                     QualType pointeeTy, uint64_t index = 0);
241
242  /// CastRetrievedVal - Used by subclasses of StoreManager to implement
243  ///  implicit casts that arise from loads from regions that are reinterpreted
244  ///  as another region.
245  SVal CastRetrievedVal(SVal val, const TypedRegion *region, QualType castTy,
246                        bool performTestOnly = true);
247
248private:
249  SVal getLValueFieldOrIvar(const Decl* decl, SVal base);
250};
251
252
253inline StoreRef::StoreRef(Store store, StoreManager & smgr)
254  : store(store), mgr(smgr) {
255  if (store)
256    mgr.incrementReferenceCount(store);
257}
258
259inline StoreRef::StoreRef(const StoreRef &sr)
260  : store(sr.store), mgr(sr.mgr)
261{
262  if (store)
263    mgr.incrementReferenceCount(store);
264}
265
266inline StoreRef::~StoreRef() {
267  if (store)
268    mgr.decrementReferenceCount(store);
269}
270
271inline StoreRef &StoreRef::operator=(StoreRef const &newStore) {
272  assert(&newStore.mgr == &mgr);
273  if (store != newStore.store) {
274    mgr.incrementReferenceCount(newStore.store);
275    mgr.decrementReferenceCount(store);
276    store = newStore.getStore();
277  }
278  return *this;
279}
280
281// FIXME: Do we still need this?
282/// SubRegionMap - An abstract interface that represents a queryable map
283///  between MemRegion objects and their subregions.
284class SubRegionMap {
285public:
286  virtual ~SubRegionMap() {}
287
288  class Visitor {
289  public:
290    virtual ~Visitor() {}
291    virtual bool Visit(const MemRegion* Parent, const MemRegion* SubRegion) = 0;
292  };
293
294  virtual bool iterSubRegions(const MemRegion *region, Visitor& V) const = 0;
295};
296
297// FIXME: Do we need to pass GRStateManager anymore?
298StoreManager *CreateBasicStoreManager(GRStateManager& StMgr);
299StoreManager *CreateRegionStoreManager(GRStateManager& StMgr);
300StoreManager *CreateFieldsOnlyRegionStoreManager(GRStateManager& StMgr);
301StoreManager *CreateFlatStoreManager(GRStateManager &StMgr);
302
303} // end GR namespace
304
305} // end clang namespace
306
307#endif
308