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_STATICANALYZER_CORE_PATHSENSITIVE_STORE_H
15 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_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
23 namespace clang {
24
25 class Stmt;
26 class Expr;
27 class ObjCIvarDecl;
28 class CXXBasePath;
29 class StackFrameContext;
30
31 namespace ento {
32
33 class CallEvent;
34 class ProgramState;
35 class ProgramStateManager;
36 class ScanReachableSymbols;
37
38 typedef llvm::DenseSet<SymbolRef> InvalidatedSymbols;
39
40 class StoreManager {
41 protected:
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
51 public:
~StoreManager()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.
getRegionManager()85 MemRegionManager& getRegionManager() { return MRMgr; }
86
getLValueVar(const VarDecl * VD,const LocationContext * LC)87 virtual Loc getLValueVar(const VarDecl *VD, const LocationContext *LC) {
88 return svalBuilder.makeLoc(MRMgr.getVarRegion(VD, LC));
89 }
90
getLValueCompoundLiteral(const CompoundLiteralExpr * CL,const LocationContext * LC)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
getLValueField(const FieldDecl * D,SVal Base)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.
getSizeInElements(ProgramStateRef state,const MemRegion * region,QualType EleTy)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.
incrementReferenceCount(Store store)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.
decrementReferenceCount(Store store)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:
FindUniqueBinding(SymbolRef sym)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 explicit operator bool() { return First && Binding; }
getRegion()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
235 protected:
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
245 private:
246 SVal getLValueFieldOrIvar(const Decl *decl, SVal base);
247 };
248
249
StoreRef(Store store,StoreManager & smgr)250 inline StoreRef::StoreRef(Store store, StoreManager & smgr)
251 : store(store), mgr(smgr) {
252 if (store)
253 mgr.incrementReferenceCount(store);
254 }
255
StoreRef(const StoreRef & sr)256 inline StoreRef::StoreRef(const StoreRef &sr)
257 : store(sr.store), mgr(sr.mgr)
258 {
259 if (store)
260 mgr.incrementReferenceCount(store);
261 }
262
~StoreRef()263 inline StoreRef::~StoreRef() {
264 if (store)
265 mgr.decrementReferenceCount(store);
266 }
267
268 inline 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?
279 std::unique_ptr<StoreManager>
280 CreateRegionStoreManager(ProgramStateManager &StMgr);
281 std::unique_ptr<StoreManager>
282 CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr);
283
284 } // end GR namespace
285
286 } // end clang namespace
287
288 #endif
289