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/DeclarationName.h" 20 #include "clang/AST/Expr.h" 21 #include "clang/AST/ExprObjC.h" 22 #include "clang/AST/Type.h" 23 #include "clang/Basic/LLVM.h" 24 #include "clang/Basic/LangOptions.h" 25 #include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h" 26 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h" 27 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState_Fwd.h" 28 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h" 29 #include "clang/StaticAnalyzer/Core/PathSensitive/SymExpr.h" 30 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" 31 #include "llvm/ADT/ImmutableList.h" 32 #include "llvm/ADT/Optional.h" 33 #include <cstdint> 34 35 namespace clang { 36 37 class BlockDecl; 38 class CXXBoolLiteralExpr; 39 class CXXMethodDecl; 40 class CXXRecordDecl; 41 class DeclaratorDecl; 42 class FunctionDecl; 43 class LocationContext; 44 class StackFrameContext; 45 class Stmt; 46 47 namespace ento { 48 49 class ConditionTruthVal; 50 class ProgramStateManager; 51 class StoreRef; 52 53 class SValBuilder { 54 virtual void anchor(); 55 56 protected: 57 ASTContext &Context; 58 59 /// Manager of APSInt values. 60 BasicValueFactory BasicVals; 61 62 /// Manages the creation of symbols. 63 SymbolManager SymMgr; 64 65 /// Manages the creation of memory regions. 66 MemRegionManager MemMgr; 67 68 ProgramStateManager &StateMgr; 69 70 /// The scalar type to use for array indices. 71 const QualType ArrayIndexTy; 72 73 /// The width of the scalar type used for array indices. 74 const unsigned ArrayIndexWidth; 75 76 virtual SVal evalCastFromNonLoc(NonLoc val, QualType castTy) = 0; 77 virtual SVal evalCastFromLoc(Loc val, QualType castTy) = 0; 78 79 public: 80 // FIXME: Make these protected again once RegionStoreManager correctly 81 // handles loads from different bound value types. 82 virtual SVal dispatchCast(SVal val, QualType castTy) = 0; 83 84 public: SValBuilder(llvm::BumpPtrAllocator & alloc,ASTContext & context,ProgramStateManager & stateMgr)85 SValBuilder(llvm::BumpPtrAllocator &alloc, ASTContext &context, 86 ProgramStateManager &stateMgr) 87 : Context(context), BasicVals(context, alloc), 88 SymMgr(context, BasicVals, alloc), MemMgr(context, alloc), 89 StateMgr(stateMgr), ArrayIndexTy(context.LongLongTy), 90 ArrayIndexWidth(context.getTypeSize(ArrayIndexTy)) {} 91 92 virtual ~SValBuilder() = default; 93 haveSameType(const SymExpr * Sym1,const SymExpr * Sym2)94 bool haveSameType(const SymExpr *Sym1, const SymExpr *Sym2) { 95 return haveSameType(Sym1->getType(), Sym2->getType()); 96 } 97 haveSameType(QualType Ty1,QualType Ty2)98 bool haveSameType(QualType Ty1, QualType Ty2) { 99 // FIXME: Remove the second disjunct when we support symbolic 100 // truncation/extension. 101 return (Context.getCanonicalType(Ty1) == Context.getCanonicalType(Ty2) || 102 (Ty1->isIntegralOrEnumerationType() && 103 Ty2->isIntegralOrEnumerationType())); 104 } 105 106 SVal evalCast(SVal val, QualType castTy, QualType originalType); 107 108 // Handles casts of type CK_IntegralCast. 109 SVal evalIntegralCast(ProgramStateRef state, SVal val, QualType castTy, 110 QualType originalType); 111 112 virtual SVal evalMinus(NonLoc val) = 0; 113 114 virtual SVal evalComplement(NonLoc val) = 0; 115 116 /// Create a new value which represents a binary expression with two non- 117 /// location operands. 118 virtual SVal evalBinOpNN(ProgramStateRef state, BinaryOperator::Opcode op, 119 NonLoc lhs, NonLoc rhs, QualType resultTy) = 0; 120 121 /// Create a new value which represents a binary expression with two memory 122 /// location operands. 123 virtual SVal evalBinOpLL(ProgramStateRef state, BinaryOperator::Opcode op, 124 Loc lhs, Loc rhs, QualType resultTy) = 0; 125 126 /// Create a new value which represents a binary expression with a memory 127 /// location and non-location operands. For example, this would be used to 128 /// evaluate a pointer arithmetic operation. 129 virtual SVal evalBinOpLN(ProgramStateRef state, BinaryOperator::Opcode op, 130 Loc lhs, NonLoc rhs, QualType resultTy) = 0; 131 132 /// Evaluates a given SVal. If the SVal has only one possible (integer) value, 133 /// that value is returned. Otherwise, returns NULL. 134 virtual const llvm::APSInt *getKnownValue(ProgramStateRef state, SVal val) = 0; 135 136 /// Simplify symbolic expressions within a given SVal. Return an SVal 137 /// that represents the same value, but is hopefully easier to work with 138 /// than the original SVal. 139 virtual SVal simplifySVal(ProgramStateRef State, SVal Val) = 0; 140 141 /// Constructs a symbolic expression for two non-location values. 142 SVal makeSymExprValNN(BinaryOperator::Opcode op, 143 NonLoc lhs, NonLoc rhs, QualType resultTy); 144 145 SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op, 146 SVal lhs, SVal rhs, QualType type); 147 148 /// \return Whether values in \p lhs and \p rhs are equal at \p state. 149 ConditionTruthVal areEqual(ProgramStateRef state, SVal lhs, SVal rhs); 150 151 SVal evalEQ(ProgramStateRef state, SVal lhs, SVal rhs); 152 153 DefinedOrUnknownSVal evalEQ(ProgramStateRef state, DefinedOrUnknownSVal lhs, 154 DefinedOrUnknownSVal rhs); 155 getContext()156 ASTContext &getContext() { return Context; } getContext()157 const ASTContext &getContext() const { return Context; } 158 getStateManager()159 ProgramStateManager &getStateManager() { return StateMgr; } 160 getConditionType()161 QualType getConditionType() const { 162 return Context.getLangOpts().CPlusPlus ? Context.BoolTy : Context.IntTy; 163 } 164 getArrayIndexType()165 QualType getArrayIndexType() const { 166 return ArrayIndexTy; 167 } 168 getBasicValueFactory()169 BasicValueFactory &getBasicValueFactory() { return BasicVals; } getBasicValueFactory()170 const BasicValueFactory &getBasicValueFactory() const { return BasicVals; } 171 getSymbolManager()172 SymbolManager &getSymbolManager() { return SymMgr; } getSymbolManager()173 const SymbolManager &getSymbolManager() const { return SymMgr; } 174 getRegionManager()175 MemRegionManager &getRegionManager() { return MemMgr; } getRegionManager()176 const MemRegionManager &getRegionManager() const { return MemMgr; } 177 178 // Forwarding methods to SymbolManager. 179 180 const SymbolConjured* conjureSymbol(const Stmt *stmt, 181 const LocationContext *LCtx, 182 QualType type, 183 unsigned visitCount, 184 const void *symbolTag = nullptr) { 185 return SymMgr.conjureSymbol(stmt, LCtx, type, visitCount, symbolTag); 186 } 187 188 const SymbolConjured* conjureSymbol(const Expr *expr, 189 const LocationContext *LCtx, 190 unsigned visitCount, 191 const void *symbolTag = nullptr) { 192 return SymMgr.conjureSymbol(expr, LCtx, visitCount, symbolTag); 193 } 194 195 /// Construct an SVal representing '0' for the specified type. 196 DefinedOrUnknownSVal makeZeroVal(QualType type); 197 198 /// Make a unique symbol for value of region. 199 DefinedOrUnknownSVal getRegionValueSymbolVal(const TypedValueRegion *region); 200 201 /// Create a new symbol with a unique 'name'. 202 /// 203 /// We resort to conjured symbols when we cannot construct a derived symbol. 204 /// The advantage of symbols derived/built from other symbols is that we 205 /// preserve the relation between related(or even equivalent) expressions, so 206 /// conjured symbols should be used sparingly. 207 DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag, 208 const Expr *expr, 209 const LocationContext *LCtx, 210 unsigned count); 211 DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag, 212 const Expr *expr, 213 const LocationContext *LCtx, 214 QualType type, 215 unsigned count); 216 DefinedOrUnknownSVal conjureSymbolVal(const Stmt *stmt, 217 const LocationContext *LCtx, 218 QualType type, 219 unsigned visitCount); 220 221 /// Conjure a symbol representing heap allocated memory region. 222 /// 223 /// Note, the expression should represent a location. 224 DefinedOrUnknownSVal getConjuredHeapSymbolVal(const Expr *E, 225 const LocationContext *LCtx, 226 unsigned Count); 227 228 DefinedOrUnknownSVal getDerivedRegionValueSymbolVal( 229 SymbolRef parentSymbol, const TypedValueRegion *region); 230 231 DefinedSVal getMetadataSymbolVal(const void *symbolTag, 232 const MemRegion *region, 233 const Expr *expr, QualType type, 234 const LocationContext *LCtx, 235 unsigned count); 236 237 DefinedSVal getMemberPointer(const DeclaratorDecl *DD); 238 239 DefinedSVal getFunctionPointer(const FunctionDecl *func); 240 241 DefinedSVal getBlockPointer(const BlockDecl *block, CanQualType locTy, 242 const LocationContext *locContext, 243 unsigned blockCount); 244 245 /// Returns the value of \p E, if it can be determined in a non-path-sensitive 246 /// manner. 247 /// 248 /// If \p E is not a constant or cannot be modeled, returns \c None. 249 Optional<SVal> getConstantVal(const Expr *E); 250 makeCompoundVal(QualType type,llvm::ImmutableList<SVal> vals)251 NonLoc makeCompoundVal(QualType type, llvm::ImmutableList<SVal> vals) { 252 return nonloc::CompoundVal(BasicVals.getCompoundValData(type, vals)); 253 } 254 makeLazyCompoundVal(const StoreRef & store,const TypedValueRegion * region)255 NonLoc makeLazyCompoundVal(const StoreRef &store, 256 const TypedValueRegion *region) { 257 return nonloc::LazyCompoundVal( 258 BasicVals.getLazyCompoundValData(store, region)); 259 } 260 makePointerToMember(const DeclaratorDecl * DD)261 NonLoc makePointerToMember(const DeclaratorDecl *DD) { 262 return nonloc::PointerToMember(DD); 263 } 264 makePointerToMember(const PointerToMemberData * PTMD)265 NonLoc makePointerToMember(const PointerToMemberData *PTMD) { 266 return nonloc::PointerToMember(PTMD); 267 } 268 makeZeroArrayIndex()269 NonLoc makeZeroArrayIndex() { 270 return nonloc::ConcreteInt(BasicVals.getValue(0, ArrayIndexTy)); 271 } 272 makeArrayIndex(uint64_t idx)273 NonLoc makeArrayIndex(uint64_t idx) { 274 return nonloc::ConcreteInt(BasicVals.getValue(idx, ArrayIndexTy)); 275 } 276 277 SVal convertToArrayIndex(SVal val); 278 makeIntVal(const IntegerLiteral * integer)279 nonloc::ConcreteInt makeIntVal(const IntegerLiteral* integer) { 280 return nonloc::ConcreteInt( 281 BasicVals.getValue(integer->getValue(), 282 integer->getType()->isUnsignedIntegerOrEnumerationType())); 283 } 284 makeBoolVal(const ObjCBoolLiteralExpr * boolean)285 nonloc::ConcreteInt makeBoolVal(const ObjCBoolLiteralExpr *boolean) { 286 return makeTruthVal(boolean->getValue(), boolean->getType()); 287 } 288 289 nonloc::ConcreteInt makeBoolVal(const CXXBoolLiteralExpr *boolean); 290 makeIntVal(const llvm::APSInt & integer)291 nonloc::ConcreteInt makeIntVal(const llvm::APSInt& integer) { 292 return nonloc::ConcreteInt(BasicVals.getValue(integer)); 293 } 294 makeIntLocVal(const llvm::APSInt & integer)295 loc::ConcreteInt makeIntLocVal(const llvm::APSInt &integer) { 296 return loc::ConcreteInt(BasicVals.getValue(integer)); 297 } 298 makeIntVal(const llvm::APInt & integer,bool isUnsigned)299 NonLoc makeIntVal(const llvm::APInt& integer, bool isUnsigned) { 300 return nonloc::ConcreteInt(BasicVals.getValue(integer, isUnsigned)); 301 } 302 makeIntVal(uint64_t integer,QualType type)303 DefinedSVal makeIntVal(uint64_t integer, QualType type) { 304 if (Loc::isLocType(type)) 305 return loc::ConcreteInt(BasicVals.getValue(integer, type)); 306 307 return nonloc::ConcreteInt(BasicVals.getValue(integer, type)); 308 } 309 makeIntVal(uint64_t integer,bool isUnsigned)310 NonLoc makeIntVal(uint64_t integer, bool isUnsigned) { 311 return nonloc::ConcreteInt(BasicVals.getIntValue(integer, isUnsigned)); 312 } 313 makeIntValWithPtrWidth(uint64_t integer,bool isUnsigned)314 NonLoc makeIntValWithPtrWidth(uint64_t integer, bool isUnsigned) { 315 return nonloc::ConcreteInt( 316 BasicVals.getIntWithPtrWidth(integer, isUnsigned)); 317 } 318 makeLocAsInteger(Loc loc,unsigned bits)319 NonLoc makeLocAsInteger(Loc loc, unsigned bits) { 320 return nonloc::LocAsInteger(BasicVals.getPersistentSValWithData(loc, bits)); 321 } 322 323 NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op, 324 const llvm::APSInt& rhs, QualType type); 325 326 NonLoc makeNonLoc(const llvm::APSInt& rhs, BinaryOperator::Opcode op, 327 const SymExpr *lhs, QualType type); 328 329 NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op, 330 const SymExpr *rhs, QualType type); 331 332 /// Create a NonLoc value for cast. 333 NonLoc makeNonLoc(const SymExpr *operand, QualType fromTy, QualType toTy); 334 makeTruthVal(bool b,QualType type)335 nonloc::ConcreteInt makeTruthVal(bool b, QualType type) { 336 return nonloc::ConcreteInt(BasicVals.getTruthValue(b, type)); 337 } 338 makeTruthVal(bool b)339 nonloc::ConcreteInt makeTruthVal(bool b) { 340 return nonloc::ConcreteInt(BasicVals.getTruthValue(b)); 341 } 342 343 /// Create NULL pointer, with proper pointer bit-width for given address 344 /// space. 345 /// \param type pointer type. makeNullWithType(QualType type)346 Loc makeNullWithType(QualType type) { 347 return loc::ConcreteInt(BasicVals.getZeroWithTypeSize(type)); 348 } 349 makeNull()350 Loc makeNull() { 351 return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth()); 352 } 353 makeLoc(SymbolRef sym)354 Loc makeLoc(SymbolRef sym) { 355 return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym)); 356 } 357 makeLoc(const MemRegion * region)358 Loc makeLoc(const MemRegion* region) { 359 return loc::MemRegionVal(region); 360 } 361 makeLoc(const AddrLabelExpr * expr)362 Loc makeLoc(const AddrLabelExpr *expr) { 363 return loc::GotoLabel(expr->getLabel()); 364 } 365 makeLoc(const llvm::APSInt & integer)366 Loc makeLoc(const llvm::APSInt& integer) { 367 return loc::ConcreteInt(BasicVals.getValue(integer)); 368 } 369 370 /// Make an SVal that represents the given symbol. This follows the convention 371 /// of representing Loc-type symbols (symbolic pointers and references) 372 /// as Loc values wrapping the symbol rather than as plain symbol values. makeSymbolVal(SymbolRef Sym)373 SVal makeSymbolVal(SymbolRef Sym) { 374 if (Loc::isLocType(Sym->getType())) 375 return makeLoc(Sym); 376 return nonloc::SymbolVal(Sym); 377 } 378 379 /// Return a memory region for the 'this' object reference. 380 loc::MemRegionVal getCXXThis(const CXXMethodDecl *D, 381 const StackFrameContext *SFC); 382 383 /// Return a memory region for the 'this' object reference. 384 loc::MemRegionVal getCXXThis(const CXXRecordDecl *D, 385 const StackFrameContext *SFC); 386 }; 387 388 SValBuilder* createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc, 389 ASTContext &context, 390 ProgramStateManager &stateMgr); 391 392 } // namespace ento 393 394 } // namespace clang 395 396 #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SVALBUILDER_H 397