| 1 | //===- Store.h - Interface for maps from Locations to Values ----*- C++ -*-===// |
|---|---|
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | // |
| 9 | // This file defined the types Store and StoreManager. |
| 10 | // |
| 11 | //===----------------------------------------------------------------------===// |
| 12 | |
| 13 | #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_STORE_H |
| 14 | #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_STORE_H |
| 15 | |
| 16 | #include "clang/AST/Type.h" |
| 17 | #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h" |
| 18 | #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState_Fwd.h" |
| 19 | #include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h" |
| 20 | #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h" |
| 21 | #include "clang/StaticAnalyzer/Core/PathSensitive/StoreRef.h" |
| 22 | #include "clang/StaticAnalyzer/Core/PathSensitive/SymExpr.h" |
| 23 | #include "clang/Basic/LLVM.h" |
| 24 | #include "llvm/ADT/ArrayRef.h" |
| 25 | #include "llvm/ADT/DenseSet.h" |
| 26 | #include "llvm/ADT/Optional.h" |
| 27 | #include "llvm/ADT/SmallVector.h" |
| 28 | #include <cassert> |
| 29 | #include <cstdint> |
| 30 | #include <memory> |
| 31 | |
| 32 | namespace clang { |
| 33 | |
| 34 | class ASTContext; |
| 35 | class CastExpr; |
| 36 | class CompoundLiteralExpr; |
| 37 | class CXXBasePath; |
| 38 | class Decl; |
| 39 | class Expr; |
| 40 | class LocationContext; |
| 41 | class ObjCIvarDecl; |
| 42 | class StackFrameContext; |
| 43 | |
| 44 | namespace ento { |
| 45 | |
| 46 | class CallEvent; |
| 47 | class ProgramStateManager; |
| 48 | class ScanReachableSymbols; |
| 49 | class SymbolReaper; |
| 50 | |
| 51 | using InvalidatedSymbols = llvm::DenseSet<SymbolRef>; |
| 52 | |
| 53 | class StoreManager { |
| 54 | protected: |
| 55 | SValBuilder &svalBuilder; |
| 56 | ProgramStateManager &StateMgr; |
| 57 | |
| 58 | /// MRMgr - Manages region objects associated with this StoreManager. |
| 59 | MemRegionManager &MRMgr; |
| 60 | ASTContext &Ctx; |
| 61 | |
| 62 | StoreManager(ProgramStateManager &stateMgr); |
| 63 | |
| 64 | public: |
| 65 | virtual ~StoreManager() = default; |
| 66 | |
| 67 | /// Return the value bound to specified location in a given state. |
| 68 | /// \param[in] store The store in which to make the lookup. |
| 69 | /// \param[in] loc The symbolic memory location. |
| 70 | /// \param[in] T An optional type that provides a hint indicating the |
| 71 | /// expected type of the returned value. This is used if the value is |
| 72 | /// lazily computed. |
| 73 | /// \return The value bound to the location \c loc. |
| 74 | virtual SVal getBinding(Store store, Loc loc, QualType T = QualType()) = 0; |
| 75 | |
| 76 | /// Return the default value bound to a region in a given store. The default |
| 77 | /// binding is the value of sub-regions that were not initialized separately |
| 78 | /// from their base region. For example, if the structure is zero-initialized |
| 79 | /// upon construction, this method retrieves the concrete zero value, even if |
| 80 | /// some or all fields were later overwritten manually. Default binding may be |
| 81 | /// an unknown, undefined, concrete, or symbolic value. |
| 82 | /// \param[in] store The store in which to make the lookup. |
| 83 | /// \param[in] R The region to find the default binding for. |
| 84 | /// \return The default value bound to the region in the store, if a default |
| 85 | /// binding exists. |
| 86 | virtual Optional<SVal> getDefaultBinding(Store store, const MemRegion *R) = 0; |
| 87 | |
| 88 | /// Return the default value bound to a LazyCompoundVal. The default binding |
| 89 | /// is used to represent the value of any fields or elements within the |
| 90 | /// structure represented by the LazyCompoundVal which were not initialized |
| 91 | /// explicitly separately from the whole structure. Default binding may be an |
| 92 | /// unknown, undefined, concrete, or symbolic value. |
| 93 | /// \param[in] lcv The lazy compound value. |
| 94 | /// \return The default value bound to the LazyCompoundVal \c lcv, if a |
| 95 | /// default binding exists. |
| 96 | Optional<SVal> getDefaultBinding(nonloc::LazyCompoundVal lcv) { |
| 97 | return getDefaultBinding(lcv.getStore(), lcv.getRegion()); |
| 98 | } |
| 99 | |
| 100 | /// Return a store with the specified value bound to the given location. |
| 101 | /// \param[in] store The store in which to make the binding. |
| 102 | /// \param[in] loc The symbolic memory location. |
| 103 | /// \param[in] val The value to bind to location \c loc. |
| 104 | /// \return A StoreRef object that contains the same |
| 105 | /// bindings as \c store with the addition of having the value specified |
| 106 | /// by \c val bound to the location given for \c loc. |
| 107 | virtual StoreRef Bind(Store store, Loc loc, SVal val) = 0; |
| 108 | |
| 109 | /// Return a store with the specified value bound to all sub-regions of the |
| 110 | /// region. The region must not have previous bindings. If you need to |
| 111 | /// invalidate existing bindings, consider invalidateRegions(). |
| 112 | virtual StoreRef BindDefaultInitial(Store store, const MemRegion *R, |
| 113 | SVal V) = 0; |
| 114 | |
| 115 | /// Return a store with in which all values within the given region are |
| 116 | /// reset to zero. This method is allowed to overwrite previous bindings. |
| 117 | virtual StoreRef BindDefaultZero(Store store, const MemRegion *R) = 0; |
| 118 | |
| 119 | /// Create a new store with the specified binding removed. |
| 120 | /// \param ST the original store, that is the basis for the new store. |
| 121 | /// \param L the location whose binding should be removed. |
| 122 | virtual StoreRef killBinding(Store ST, Loc L) = 0; |
| 123 | |
| 124 | /// getInitialStore - Returns the initial "empty" store representing the |
| 125 | /// value bindings upon entry to an analyzed function. |
| 126 | virtual StoreRef getInitialStore(const LocationContext *InitLoc) = 0; |
| 127 | |
| 128 | /// getRegionManager - Returns the internal RegionManager object that is |
| 129 | /// used to query and manipulate MemRegion objects. |
| 130 | MemRegionManager& getRegionManager() { return MRMgr; } |
| 131 | |
| 132 | SValBuilder& getSValBuilder() { return svalBuilder; } |
| 133 | |
| 134 | virtual Loc getLValueVar(const VarDecl *VD, const LocationContext *LC) { |
| 135 | return svalBuilder.makeLoc(MRMgr.getVarRegion(VD, LC)); |
| 136 | } |
| 137 | |
| 138 | Loc getLValueCompoundLiteral(const CompoundLiteralExpr *CL, |
| 139 | const LocationContext *LC) { |
| 140 | return loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC)); |
| 141 | } |
| 142 | |
| 143 | virtual SVal getLValueIvar(const ObjCIvarDecl *decl, SVal base); |
| 144 | |
| 145 | virtual SVal getLValueField(const FieldDecl *D, SVal Base) { |
| 146 | return getLValueFieldOrIvar(D, Base); |
| 147 | } |
| 148 | |
| 149 | virtual SVal getLValueElement(QualType elementType, NonLoc offset, SVal Base); |
| 150 | |
| 151 | // FIXME: This should soon be eliminated altogether; clients should deal with |
| 152 | // region extents directly. |
| 153 | virtual DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state, |
| 154 | const MemRegion *region, |
| 155 | QualType EleTy) { |
| 156 | return UnknownVal(); |
| 157 | } |
| 158 | |
| 159 | /// ArrayToPointer - Used by ExprEngine::VistCast to handle implicit |
| 160 | /// conversions between arrays and pointers. |
| 161 | virtual SVal ArrayToPointer(Loc Array, QualType ElementTy) = 0; |
| 162 | |
| 163 | /// Evaluates a chain of derived-to-base casts through the path specified in |
| 164 | /// \p Cast. |
| 165 | SVal evalDerivedToBase(SVal Derived, const CastExpr *Cast); |
| 166 | |
| 167 | /// Evaluates a chain of derived-to-base casts through the specified path. |
| 168 | SVal evalDerivedToBase(SVal Derived, const CXXBasePath &CastPath); |
| 169 | |
| 170 | /// Evaluates a derived-to-base cast through a single level of derivation. |
| 171 | SVal evalDerivedToBase(SVal Derived, QualType DerivedPtrType, |
| 172 | bool IsVirtual); |
| 173 | |
| 174 | /// Attempts to do a down cast. Used to model BaseToDerived and C++ |
| 175 | /// dynamic_cast. |
| 176 | /// The callback may result in the following 3 scenarios: |
| 177 | /// - Successful cast (ex: derived is subclass of base). |
| 178 | /// - Failed cast (ex: derived is definitely not a subclass of base). |
| 179 | /// The distinction of this case from the next one is necessary to model |
| 180 | /// dynamic_cast. |
| 181 | /// - We don't know (base is a symbolic region and we don't have |
| 182 | /// enough info to determine if the cast will succeed at run time). |
| 183 | /// The function returns an SVal representing the derived class; it's |
| 184 | /// valid only if Failed flag is set to false. |
| 185 | SVal attemptDownCast(SVal Base, QualType DerivedPtrType, bool &Failed); |
| 186 | |
| 187 | const ElementRegion *GetElementZeroRegion(const SubRegion *R, QualType T); |
| 188 | |
| 189 | /// castRegion - Used by ExprEngine::VisitCast to handle casts from |
| 190 | /// a MemRegion* to a specific location type. 'R' is the region being |
| 191 | /// casted and 'CastToTy' the result type of the cast. |
| 192 | const MemRegion *castRegion(const MemRegion *region, QualType CastToTy); |
| 193 | |
| 194 | virtual StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx, |
| 195 | SymbolReaper &SymReaper) = 0; |
| 196 | |
| 197 | virtual bool includedInBindings(Store store, |
| 198 | const MemRegion *region) const = 0; |
| 199 | |
| 200 | /// If the StoreManager supports it, increment the reference count of |
| 201 | /// the specified Store object. |
| 202 | virtual void incrementReferenceCount(Store store) {} |
| 203 | |
| 204 | /// If the StoreManager supports it, decrement the reference count of |
| 205 | /// the specified Store object. If the reference count hits 0, the memory |
| 206 | /// associated with the object is recycled. |
| 207 | virtual void decrementReferenceCount(Store store) {} |
| 208 | |
| 209 | using InvalidatedRegions = SmallVector<const MemRegion *, 8>; |
| 210 | |
| 211 | /// invalidateRegions - Clears out the specified regions from the store, |
| 212 | /// marking their values as unknown. Depending on the store, this may also |
| 213 | /// invalidate additional regions that may have changed based on accessing |
| 214 | /// the given regions. Optionally, invalidates non-static globals as well. |
| 215 | /// \param[in] store The initial store |
| 216 | /// \param[in] Values The values to invalidate. |
| 217 | /// \param[in] E The current statement being evaluated. Used to conjure |
| 218 | /// symbols to mark the values of invalidated regions. |
| 219 | /// \param[in] Count The current block count. Used to conjure |
| 220 | /// symbols to mark the values of invalidated regions. |
| 221 | /// \param[in] Call The call expression which will be used to determine which |
| 222 | /// globals should get invalidated. |
| 223 | /// \param[in,out] IS A set to fill with any symbols that are no longer |
| 224 | /// accessible. Pass \c NULL if this information will not be used. |
| 225 | /// \param[in] ITraits Information about invalidation for a particular |
| 226 | /// region/symbol. |
| 227 | /// \param[in,out] InvalidatedTopLevel A vector to fill with regions |
| 228 | //// explicitly being invalidated. Pass \c NULL if this |
| 229 | /// information will not be used. |
| 230 | /// \param[in,out] Invalidated A vector to fill with any regions being |
| 231 | /// invalidated. This should include any regions explicitly invalidated |
| 232 | /// even if they do not currently have bindings. Pass \c NULL if this |
| 233 | /// information will not be used. |
| 234 | virtual StoreRef invalidateRegions(Store store, |
| 235 | ArrayRef<SVal> Values, |
| 236 | const Expr *E, unsigned Count, |
| 237 | const LocationContext *LCtx, |
| 238 | const CallEvent *Call, |
| 239 | InvalidatedSymbols &IS, |
| 240 | RegionAndSymbolInvalidationTraits &ITraits, |
| 241 | InvalidatedRegions *InvalidatedTopLevel, |
| 242 | InvalidatedRegions *Invalidated) = 0; |
| 243 | |
| 244 | /// enterStackFrame - Let the StoreManager to do something when execution |
| 245 | /// engine is about to execute into a callee. |
| 246 | StoreRef enterStackFrame(Store store, |
| 247 | const CallEvent &Call, |
| 248 | const StackFrameContext *CalleeCtx); |
| 249 | |
| 250 | /// Finds the transitive closure of symbols within the given region. |
| 251 | /// |
| 252 | /// Returns false if the visitor aborted the scan. |
| 253 | virtual bool scanReachableSymbols(Store S, const MemRegion *R, |
| 254 | ScanReachableSymbols &Visitor) = 0; |
| 255 | |
| 256 | virtual void print(Store store, raw_ostream &Out, const char* nl) = 0; |
| 257 | |
| 258 | class BindingsHandler { |
| 259 | public: |
| 260 | virtual ~BindingsHandler(); |
| 261 | |
| 262 | /// \return whether the iteration should continue. |
| 263 | virtual bool HandleBinding(StoreManager& SMgr, Store store, |
| 264 | const MemRegion *region, SVal val) = 0; |
| 265 | }; |
| 266 | |
| 267 | class FindUniqueBinding : public BindingsHandler { |
| 268 | SymbolRef Sym; |
| 269 | const MemRegion* Binding = nullptr; |
| 270 | bool First = true; |
| 271 | |
| 272 | public: |
| 273 | FindUniqueBinding(SymbolRef sym) : Sym(sym) {} |
| 274 | |
| 275 | explicit operator bool() { return First && Binding; } |
| 276 | |
| 277 | bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R, |
| 278 | SVal val) override; |
| 279 | const MemRegion *getRegion() { return Binding; } |
| 280 | }; |
| 281 | |
| 282 | /// iterBindings - Iterate over the bindings in the Store. |
| 283 | virtual void iterBindings(Store store, BindingsHandler& f) = 0; |
| 284 | |
| 285 | protected: |
| 286 | const ElementRegion *MakeElementRegion(const SubRegion *baseRegion, |
| 287 | QualType pointeeTy, |
| 288 | uint64_t index = 0); |
| 289 | |
| 290 | /// CastRetrievedVal - Used by subclasses of StoreManager to implement |
| 291 | /// implicit casts that arise from loads from regions that are reinterpreted |
| 292 | /// as another region. |
| 293 | SVal CastRetrievedVal(SVal val, const TypedValueRegion *region, |
| 294 | QualType castTy); |
| 295 | |
| 296 | private: |
| 297 | SVal getLValueFieldOrIvar(const Decl *decl, SVal base); |
| 298 | }; |
| 299 | |
| 300 | inline StoreRef::StoreRef(Store store, StoreManager & smgr) |
| 301 | : store(store), mgr(smgr) { |
| 302 | if (store) |
| 303 | mgr.incrementReferenceCount(store); |
| 304 | } |
| 305 | |
| 306 | inline StoreRef::StoreRef(const StoreRef &sr) |
| 307 | : store(sr.store), mgr(sr.mgr) |
| 308 | { |
| 309 | if (store) |
| 310 | mgr.incrementReferenceCount(store); |
| 311 | } |
| 312 | |
| 313 | inline StoreRef::~StoreRef() { |
| 314 | if (store) |
| 315 | mgr.decrementReferenceCount(store); |
| 316 | } |
| 317 | |
| 318 | inline StoreRef &StoreRef::operator=(StoreRef const &newStore) { |
| 319 | assert(&newStore.mgr == &mgr); |
| 320 | if (store != newStore.store) { |
| 321 | mgr.incrementReferenceCount(newStore.store); |
| 322 | mgr.decrementReferenceCount(store); |
| 323 | store = newStore.getStore(); |
| 324 | } |
| 325 | return *this; |
| 326 | } |
| 327 | |
| 328 | // FIXME: Do we need to pass ProgramStateManager anymore? |
| 329 | std::unique_ptr<StoreManager> |
| 330 | CreateRegionStoreManager(ProgramStateManager &StMgr); |
| 331 | std::unique_ptr<StoreManager> |
| 332 | CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr); |
| 333 | |
| 334 | } // namespace ento |
| 335 | |
| 336 | } // namespace clang |
| 337 | |
| 338 | #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_STORE_H |
| 339 |