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
23 namespace clang {
24
25 class Stmt;
26 class Expr;
27 class ObjCIvarDecl;
28 class StackFrameContext;
29
30 namespace ento {
31
32 class CallEvent;
33 class ProgramState;
34 class ProgramStateManager;
35 class ScanReachableSymbols;
36
37 class StoreManager {
38 protected:
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
48 public:
~StoreManager()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.
getRegionManager()97 MemRegionManager& getRegionManager() { return MRMgr; }
98
getLValueVar(const VarDecl * VD,const LocationContext * LC)99 virtual Loc getLValueVar(const VarDecl *VD, const LocationContext *LC) {
100 return svalBuilder.makeLoc(MRMgr.getVarRegion(VD, LC));
101 }
102
getLValueCompoundLiteral(const CompoundLiteralExpr * CL,const LocationContext * LC)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
getLValueField(const FieldDecl * D,SVal Base)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.
getSizeInElements(ProgramStateRef state,const MemRegion * region,QualType EleTy)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.
incrementReferenceCount(Store store)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.
decrementReferenceCount(Store store)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:
FindUniqueBinding(SymbolRef sym)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; }
getRegion()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
236 protected:
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
246 private:
247 SVal getLValueFieldOrIvar(const Decl *decl, SVal base);
248 };
249
250
StoreRef(Store store,StoreManager & smgr)251 inline StoreRef::StoreRef(Store store, StoreManager & smgr)
252 : store(store), mgr(smgr) {
253 if (store)
254 mgr.incrementReferenceCount(store);
255 }
256
StoreRef(const StoreRef & sr)257 inline StoreRef::StoreRef(const StoreRef &sr)
258 : store(sr.store), mgr(sr.mgr)
259 {
260 if (store)
261 mgr.incrementReferenceCount(store);
262 }
263
~StoreRef()264 inline StoreRef::~StoreRef() {
265 if (store)
266 mgr.decrementReferenceCount(store);
267 }
268
269 inline 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?
280 StoreManager *CreateRegionStoreManager(ProgramStateManager& StMgr);
281 StoreManager *CreateFieldsOnlyRegionStoreManager(ProgramStateManager& StMgr);
282
283 } // end GR namespace
284
285 } // end clang namespace
286
287 #endif
288