1 // SValBuilder.h - Construction of SVals from evaluating expressions -*- 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 defines SValBuilder, a class that defines the interface for 11 // "symbolical evaluators" which construct an SVal from an expression. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SVALBUILDER_H 16 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SVALBUILDER_H 17 18 #include "clang/AST/ASTContext.h" 19 #include "clang/AST/Expr.h" 20 #include "clang/AST/ExprObjC.h" 21 #include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h" 22 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h" 23 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h" 24 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" 25 26 namespace clang { 27 28 class CXXBoolLiteralExpr; 29 30 namespace ento { 31 32 class SValBuilder { 33 virtual void anchor(); 34 protected: 35 ASTContext &Context; 36 37 /// Manager of APSInt values. 38 BasicValueFactory BasicVals; 39 40 /// Manages the creation of symbols. 41 SymbolManager SymMgr; 42 43 /// Manages the creation of memory regions. 44 MemRegionManager MemMgr; 45 46 ProgramStateManager &StateMgr; 47 48 /// The scalar type to use for array indices. 49 const QualType ArrayIndexTy; 50 51 /// The width of the scalar type used for array indices. 52 const unsigned ArrayIndexWidth; 53 54 virtual SVal evalCastFromNonLoc(NonLoc val, QualType castTy) = 0; 55 virtual SVal evalCastFromLoc(Loc val, QualType castTy) = 0; 56 57 public: 58 // FIXME: Make these protected again once RegionStoreManager correctly 59 // handles loads from different bound value types. 60 virtual SVal dispatchCast(SVal val, QualType castTy) = 0; 61 62 public: 63 SValBuilder(llvm::BumpPtrAllocator &alloc, ASTContext &context, 64 ProgramStateManager &stateMgr) 65 : Context(context), BasicVals(context, alloc), 66 SymMgr(context, BasicVals, alloc), 67 MemMgr(context, alloc), 68 StateMgr(stateMgr), 69 ArrayIndexTy(context.LongLongTy), 70 ArrayIndexWidth(context.getTypeSize(ArrayIndexTy)) {} 71 72 virtual ~SValBuilder() {} 73 74 bool haveSameType(const SymExpr *Sym1, const SymExpr *Sym2) { 75 return haveSameType(Sym1->getType(), Sym2->getType()); 76 } 77 78 bool haveSameType(QualType Ty1, QualType Ty2) { 79 // FIXME: Remove the second disjunct when we support symbolic 80 // truncation/extension. 81 return (Context.getCanonicalType(Ty1) == Context.getCanonicalType(Ty2) || 82 (Ty1->isIntegralOrEnumerationType() && 83 Ty2->isIntegralOrEnumerationType())); 84 } 85 86 SVal evalCast(SVal val, QualType castTy, QualType originalType); 87 88 // Handles casts of type CK_IntegralCast. 89 SVal evalIntegralCast(ProgramStateRef state, SVal val, QualType castTy, 90 QualType originalType); 91 92 virtual SVal evalMinus(NonLoc val) = 0; 93 94 virtual SVal evalComplement(NonLoc val) = 0; 95 96 /// Create a new value which represents a binary expression with two non- 97 /// location operands. 98 virtual SVal evalBinOpNN(ProgramStateRef state, BinaryOperator::Opcode op, 99 NonLoc lhs, NonLoc rhs, QualType resultTy) = 0; 100 101 /// Create a new value which represents a binary expression with two memory 102 /// location operands. 103 virtual SVal evalBinOpLL(ProgramStateRef state, BinaryOperator::Opcode op, 104 Loc lhs, Loc rhs, QualType resultTy) = 0; 105 106 /// Create a new value which represents a binary expression with a memory 107 /// location and non-location operands. For example, this would be used to 108 /// evaluate a pointer arithmetic operation. 109 virtual SVal evalBinOpLN(ProgramStateRef state, BinaryOperator::Opcode op, 110 Loc lhs, NonLoc rhs, QualType resultTy) = 0; 111 112 /// Evaluates a given SVal. If the SVal has only one possible (integer) value, 113 /// that value is returned. Otherwise, returns NULL. 114 virtual const llvm::APSInt *getKnownValue(ProgramStateRef state, SVal val) = 0; 115 116 /// Simplify symbolic expressions within a given SVal. Return an SVal 117 /// that represents the same value, but is hopefully easier to work with 118 /// than the original SVal. 119 virtual SVal simplifySVal(ProgramStateRef State, SVal Val) = 0; 120 121 /// Constructs a symbolic expression for two non-location values. 122 SVal makeSymExprValNN(ProgramStateRef state, BinaryOperator::Opcode op, 123 NonLoc lhs, NonLoc rhs, QualType resultTy); 124 125 SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op, 126 SVal lhs, SVal rhs, QualType type); 127 128 DefinedOrUnknownSVal evalEQ(ProgramStateRef state, DefinedOrUnknownSVal lhs, 129 DefinedOrUnknownSVal rhs); 130 131 ASTContext &getContext() { return Context; } 132 const ASTContext &getContext() const { return Context; } 133 134 ProgramStateManager &getStateManager() { return StateMgr; } 135 136 QualType getConditionType() const { 137 return Context.getLangOpts().CPlusPlus ? Context.BoolTy : Context.IntTy; 138 } 139 140 QualType getArrayIndexType() const { 141 return ArrayIndexTy; 142 } 143 144 BasicValueFactory &getBasicValueFactory() { return BasicVals; } 145 const BasicValueFactory &getBasicValueFactory() const { return BasicVals; } 146 147 SymbolManager &getSymbolManager() { return SymMgr; } 148 const SymbolManager &getSymbolManager() const { return SymMgr; } 149 150 MemRegionManager &getRegionManager() { return MemMgr; } 151 const MemRegionManager &getRegionManager() const { return MemMgr; } 152 153 // Forwarding methods to SymbolManager. 154 155 const SymbolConjured* conjureSymbol(const Stmt *stmt, 156 const LocationContext *LCtx, 157 QualType type, 158 unsigned visitCount, 159 const void *symbolTag = nullptr) { 160 return SymMgr.conjureSymbol(stmt, LCtx, type, visitCount, symbolTag); 161 } 162 163 const SymbolConjured* conjureSymbol(const Expr *expr, 164 const LocationContext *LCtx, 165 unsigned visitCount, 166 const void *symbolTag = nullptr) { 167 return SymMgr.conjureSymbol(expr, LCtx, visitCount, symbolTag); 168 } 169 170 /// Construct an SVal representing '0' for the specified type. 171 DefinedOrUnknownSVal makeZeroVal(QualType type); 172 173 /// Make a unique symbol for value of region. 174 DefinedOrUnknownSVal getRegionValueSymbolVal(const TypedValueRegion *region); 175 176 /// \brief Create a new symbol with a unique 'name'. 177 /// 178 /// We resort to conjured symbols when we cannot construct a derived symbol. 179 /// The advantage of symbols derived/built from other symbols is that we 180 /// preserve the relation between related(or even equivalent) expressions, so 181 /// conjured symbols should be used sparingly. 182 DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag, 183 const Expr *expr, 184 const LocationContext *LCtx, 185 unsigned count); 186 DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag, 187 const Expr *expr, 188 const LocationContext *LCtx, 189 QualType type, 190 unsigned count); 191 192 DefinedOrUnknownSVal conjureSymbolVal(const Stmt *stmt, 193 const LocationContext *LCtx, 194 QualType type, 195 unsigned visitCount); 196 /// \brief Conjure a symbol representing heap allocated memory region. 197 /// 198 /// Note, the expression should represent a location. 199 DefinedOrUnknownSVal getConjuredHeapSymbolVal(const Expr *E, 200 const LocationContext *LCtx, 201 unsigned Count); 202 203 DefinedOrUnknownSVal getDerivedRegionValueSymbolVal( 204 SymbolRef parentSymbol, const TypedValueRegion *region); 205 206 DefinedSVal getMetadataSymbolVal(const void *symbolTag, 207 const MemRegion *region, 208 const Expr *expr, QualType type, 209 const LocationContext *LCtx, 210 unsigned count); 211 212 DefinedSVal getMemberPointer(const DeclaratorDecl *DD); 213 214 DefinedSVal getFunctionPointer(const FunctionDecl *func); 215 216 DefinedSVal getBlockPointer(const BlockDecl *block, CanQualType locTy, 217 const LocationContext *locContext, 218 unsigned blockCount); 219 220 /// Returns the value of \p E, if it can be determined in a non-path-sensitive 221 /// manner. 222 /// 223 /// If \p E is not a constant or cannot be modeled, returns \c None. 224 Optional<SVal> getConstantVal(const Expr *E); 225 226 NonLoc makeCompoundVal(QualType type, llvm::ImmutableList<SVal> vals) { 227 return nonloc::CompoundVal(BasicVals.getCompoundValData(type, vals)); 228 } 229 230 NonLoc makeLazyCompoundVal(const StoreRef &store, 231 const TypedValueRegion *region) { 232 return nonloc::LazyCompoundVal( 233 BasicVals.getLazyCompoundValData(store, region)); 234 } 235 236 NonLoc makePointerToMember(const DeclaratorDecl *DD) { 237 return nonloc::PointerToMember(DD); 238 } 239 240 NonLoc makePointerToMember(const PointerToMemberData *PTMD) { 241 return nonloc::PointerToMember(PTMD); 242 } 243 244 NonLoc makeZeroArrayIndex() { 245 return nonloc::ConcreteInt(BasicVals.getValue(0, ArrayIndexTy)); 246 } 247 248 NonLoc makeArrayIndex(uint64_t idx) { 249 return nonloc::ConcreteInt(BasicVals.getValue(idx, ArrayIndexTy)); 250 } 251 252 SVal convertToArrayIndex(SVal val); 253 254 nonloc::ConcreteInt makeIntVal(const IntegerLiteral* integer) { 255 return nonloc::ConcreteInt( 256 BasicVals.getValue(integer->getValue(), 257 integer->getType()->isUnsignedIntegerOrEnumerationType())); 258 } 259 260 nonloc::ConcreteInt makeBoolVal(const ObjCBoolLiteralExpr *boolean) { 261 return makeTruthVal(boolean->getValue(), boolean->getType()); 262 } 263 264 nonloc::ConcreteInt makeBoolVal(const CXXBoolLiteralExpr *boolean); 265 266 nonloc::ConcreteInt makeIntVal(const llvm::APSInt& integer) { 267 return nonloc::ConcreteInt(BasicVals.getValue(integer)); 268 } 269 270 loc::ConcreteInt makeIntLocVal(const llvm::APSInt &integer) { 271 return loc::ConcreteInt(BasicVals.getValue(integer)); 272 } 273 274 NonLoc makeIntVal(const llvm::APInt& integer, bool isUnsigned) { 275 return nonloc::ConcreteInt(BasicVals.getValue(integer, isUnsigned)); 276 } 277 278 DefinedSVal makeIntVal(uint64_t integer, QualType type) { 279 if (Loc::isLocType(type)) 280 return loc::ConcreteInt(BasicVals.getValue(integer, type)); 281 282 return nonloc::ConcreteInt(BasicVals.getValue(integer, type)); 283 } 284 285 NonLoc makeIntVal(uint64_t integer, bool isUnsigned) { 286 return nonloc::ConcreteInt(BasicVals.getIntValue(integer, isUnsigned)); 287 } 288 289 NonLoc makeIntValWithPtrWidth(uint64_t integer, bool isUnsigned) { 290 return nonloc::ConcreteInt( 291 BasicVals.getIntWithPtrWidth(integer, isUnsigned)); 292 } 293 294 NonLoc makeLocAsInteger(Loc loc, unsigned bits) { 295 return nonloc::LocAsInteger(BasicVals.getPersistentSValWithData(loc, bits)); 296 } 297 298 NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op, 299 const llvm::APSInt& rhs, QualType type); 300 301 NonLoc makeNonLoc(const llvm::APSInt& rhs, BinaryOperator::Opcode op, 302 const SymExpr *lhs, QualType type); 303 304 NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op, 305 const SymExpr *rhs, QualType type); 306 307 /// \brief Create a NonLoc value for cast. 308 NonLoc makeNonLoc(const SymExpr *operand, QualType fromTy, QualType toTy); 309 310 nonloc::ConcreteInt makeTruthVal(bool b, QualType type) { 311 return nonloc::ConcreteInt(BasicVals.getTruthValue(b, type)); 312 } 313 314 nonloc::ConcreteInt makeTruthVal(bool b) { 315 return nonloc::ConcreteInt(BasicVals.getTruthValue(b)); 316 } 317 318 /// Create NULL pointer, with proper pointer bit-width for given address 319 /// space. 320 /// \param type pointer type. 321 Loc makeNullWithType(QualType type) { 322 return loc::ConcreteInt(BasicVals.getZeroWithTypeSize(type)); 323 } 324 325 Loc makeNull() { 326 return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth()); 327 } 328 329 Loc makeLoc(SymbolRef sym) { 330 return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym)); 331 } 332 333 Loc makeLoc(const MemRegion* region) { 334 return loc::MemRegionVal(region); 335 } 336 337 Loc makeLoc(const AddrLabelExpr *expr) { 338 return loc::GotoLabel(expr->getLabel()); 339 } 340 341 Loc makeLoc(const llvm::APSInt& integer) { 342 return loc::ConcreteInt(BasicVals.getValue(integer)); 343 } 344 345 /// Return a memory region for the 'this' object reference. 346 loc::MemRegionVal getCXXThis(const CXXMethodDecl *D, 347 const StackFrameContext *SFC); 348 349 /// Return a memory region for the 'this' object reference. 350 loc::MemRegionVal getCXXThis(const CXXRecordDecl *D, 351 const StackFrameContext *SFC); 352 }; 353 354 SValBuilder* createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc, 355 ASTContext &context, 356 ProgramStateManager &stateMgr); 357 358 } // end GR namespace 359 360 } // end clang namespace 361 362 #endif 363