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 /// Constructs a symbolic expression for two non-location values. 117 SVal makeSymExprValNN(ProgramStateRef state, BinaryOperator::Opcode op, 118 NonLoc lhs, NonLoc rhs, QualType resultTy); 119 120 SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op, 121 SVal lhs, SVal rhs, QualType type); 122 123 DefinedOrUnknownSVal evalEQ(ProgramStateRef state, DefinedOrUnknownSVal lhs, 124 DefinedOrUnknownSVal rhs); 125 126 ASTContext &getContext() { return Context; } 127 const ASTContext &getContext() const { return Context; } 128 129 ProgramStateManager &getStateManager() { return StateMgr; } 130 131 QualType getConditionType() const { 132 return Context.getLangOpts().CPlusPlus ? Context.BoolTy : Context.IntTy; 133 } 134 135 QualType getArrayIndexType() const { 136 return ArrayIndexTy; 137 } 138 139 BasicValueFactory &getBasicValueFactory() { return BasicVals; } 140 const BasicValueFactory &getBasicValueFactory() const { return BasicVals; } 141 142 SymbolManager &getSymbolManager() { return SymMgr; } 143 const SymbolManager &getSymbolManager() const { return SymMgr; } 144 145 MemRegionManager &getRegionManager() { return MemMgr; } 146 const MemRegionManager &getRegionManager() const { return MemMgr; } 147 148 // Forwarding methods to SymbolManager. 149 150 const SymbolConjured* conjureSymbol(const Stmt *stmt, 151 const LocationContext *LCtx, 152 QualType type, 153 unsigned visitCount, 154 const void *symbolTag = nullptr) { 155 return SymMgr.conjureSymbol(stmt, LCtx, type, visitCount, symbolTag); 156 } 157 158 const SymbolConjured* conjureSymbol(const Expr *expr, 159 const LocationContext *LCtx, 160 unsigned visitCount, 161 const void *symbolTag = nullptr) { 162 return SymMgr.conjureSymbol(expr, LCtx, visitCount, symbolTag); 163 } 164 165 /// Construct an SVal representing '0' for the specified type. 166 DefinedOrUnknownSVal makeZeroVal(QualType type); 167 168 /// Make a unique symbol for value of region. 169 DefinedOrUnknownSVal getRegionValueSymbolVal(const TypedValueRegion *region); 170 171 /// \brief Create a new symbol with a unique 'name'. 172 /// 173 /// We resort to conjured symbols when we cannot construct a derived symbol. 174 /// The advantage of symbols derived/built from other symbols is that we 175 /// preserve the relation between related(or even equivalent) expressions, so 176 /// conjured symbols should be used sparingly. 177 DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag, 178 const Expr *expr, 179 const LocationContext *LCtx, 180 unsigned count); 181 DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag, 182 const Expr *expr, 183 const LocationContext *LCtx, 184 QualType type, 185 unsigned count); 186 187 DefinedOrUnknownSVal conjureSymbolVal(const Stmt *stmt, 188 const LocationContext *LCtx, 189 QualType type, 190 unsigned visitCount); 191 /// \brief Conjure a symbol representing heap allocated memory region. 192 /// 193 /// Note, the expression should represent a location. 194 DefinedOrUnknownSVal getConjuredHeapSymbolVal(const Expr *E, 195 const LocationContext *LCtx, 196 unsigned Count); 197 198 DefinedOrUnknownSVal getDerivedRegionValueSymbolVal( 199 SymbolRef parentSymbol, const TypedValueRegion *region); 200 201 DefinedSVal getMetadataSymbolVal( 202 const void *symbolTag, const MemRegion *region, 203 const Expr *expr, QualType type, unsigned count); 204 205 DefinedSVal getFunctionPointer(const FunctionDecl *func); 206 207 DefinedSVal getBlockPointer(const BlockDecl *block, CanQualType locTy, 208 const LocationContext *locContext, 209 unsigned blockCount); 210 211 /// Returns the value of \p E, if it can be determined in a non-path-sensitive 212 /// manner. 213 /// 214 /// If \p E is not a constant or cannot be modeled, returns \c None. 215 Optional<SVal> getConstantVal(const Expr *E); 216 217 NonLoc makeCompoundVal(QualType type, llvm::ImmutableList<SVal> vals) { 218 return nonloc::CompoundVal(BasicVals.getCompoundValData(type, vals)); 219 } 220 221 NonLoc makeLazyCompoundVal(const StoreRef &store, 222 const TypedValueRegion *region) { 223 return nonloc::LazyCompoundVal( 224 BasicVals.getLazyCompoundValData(store, region)); 225 } 226 227 NonLoc makeZeroArrayIndex() { 228 return nonloc::ConcreteInt(BasicVals.getValue(0, ArrayIndexTy)); 229 } 230 231 NonLoc makeArrayIndex(uint64_t idx) { 232 return nonloc::ConcreteInt(BasicVals.getValue(idx, ArrayIndexTy)); 233 } 234 235 SVal convertToArrayIndex(SVal val); 236 237 nonloc::ConcreteInt makeIntVal(const IntegerLiteral* integer) { 238 return nonloc::ConcreteInt( 239 BasicVals.getValue(integer->getValue(), 240 integer->getType()->isUnsignedIntegerOrEnumerationType())); 241 } 242 243 nonloc::ConcreteInt makeBoolVal(const ObjCBoolLiteralExpr *boolean) { 244 return makeTruthVal(boolean->getValue(), boolean->getType()); 245 } 246 247 nonloc::ConcreteInt makeBoolVal(const CXXBoolLiteralExpr *boolean); 248 249 nonloc::ConcreteInt makeIntVal(const llvm::APSInt& integer) { 250 return nonloc::ConcreteInt(BasicVals.getValue(integer)); 251 } 252 253 loc::ConcreteInt makeIntLocVal(const llvm::APSInt &integer) { 254 return loc::ConcreteInt(BasicVals.getValue(integer)); 255 } 256 257 NonLoc makeIntVal(const llvm::APInt& integer, bool isUnsigned) { 258 return nonloc::ConcreteInt(BasicVals.getValue(integer, isUnsigned)); 259 } 260 261 DefinedSVal makeIntVal(uint64_t integer, QualType type) { 262 if (Loc::isLocType(type)) 263 return loc::ConcreteInt(BasicVals.getValue(integer, type)); 264 265 return nonloc::ConcreteInt(BasicVals.getValue(integer, type)); 266 } 267 268 NonLoc makeIntVal(uint64_t integer, bool isUnsigned) { 269 return nonloc::ConcreteInt(BasicVals.getIntValue(integer, isUnsigned)); 270 } 271 272 NonLoc makeIntValWithPtrWidth(uint64_t integer, bool isUnsigned) { 273 return nonloc::ConcreteInt( 274 BasicVals.getIntWithPtrWidth(integer, isUnsigned)); 275 } 276 277 NonLoc makeLocAsInteger(Loc loc, unsigned bits) { 278 return nonloc::LocAsInteger(BasicVals.getPersistentSValWithData(loc, bits)); 279 } 280 281 NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op, 282 const llvm::APSInt& rhs, QualType type); 283 284 NonLoc makeNonLoc(const llvm::APSInt& rhs, BinaryOperator::Opcode op, 285 const SymExpr *lhs, QualType type); 286 287 NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op, 288 const SymExpr *rhs, QualType type); 289 290 /// \brief Create a NonLoc value for cast. 291 NonLoc makeNonLoc(const SymExpr *operand, QualType fromTy, QualType toTy); 292 293 nonloc::ConcreteInt makeTruthVal(bool b, QualType type) { 294 return nonloc::ConcreteInt(BasicVals.getTruthValue(b, type)); 295 } 296 297 nonloc::ConcreteInt makeTruthVal(bool b) { 298 return nonloc::ConcreteInt(BasicVals.getTruthValue(b)); 299 } 300 301 Loc makeNull() { 302 return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth()); 303 } 304 305 Loc makeLoc(SymbolRef sym) { 306 return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym)); 307 } 308 309 Loc makeLoc(const MemRegion* region) { 310 return loc::MemRegionVal(region); 311 } 312 313 Loc makeLoc(const AddrLabelExpr *expr) { 314 return loc::GotoLabel(expr->getLabel()); 315 } 316 317 Loc makeLoc(const llvm::APSInt& integer) { 318 return loc::ConcreteInt(BasicVals.getValue(integer)); 319 } 320 321 /// Return a memory region for the 'this' object reference. 322 loc::MemRegionVal getCXXThis(const CXXMethodDecl *D, 323 const StackFrameContext *SFC); 324 325 /// Return a memory region for the 'this' object reference. 326 loc::MemRegionVal getCXXThis(const CXXRecordDecl *D, 327 const StackFrameContext *SFC); 328 }; 329 330 SValBuilder* createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc, 331 ASTContext &context, 332 ProgramStateManager &stateMgr); 333 334 } // end GR namespace 335 336 } // end clang namespace 337 338 #endif 339
