1 // SValBuilder.h - Construction of SVals from evaluating expressions -*- 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 defines SValBuilder, a class that defines the interface for 10 // "symbolical evaluators" which construct an SVal from an expression. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SVALBUILDER_H 15 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SVALBUILDER_H 16 17 #include "clang/AST/ASTContext.h" 18 #include "clang/AST/DeclarationName.h" 19 #include "clang/AST/Expr.h" 20 #include "clang/AST/ExprObjC.h" 21 #include "clang/AST/Type.h" 22 #include "clang/Basic/LLVM.h" 23 #include "clang/Basic/LangOptions.h" 24 #include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h" 25 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h" 26 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState_Fwd.h" 27 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h" 28 #include "clang/StaticAnalyzer/Core/PathSensitive/SymExpr.h" 29 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" 30 #include "llvm/ADT/ImmutableList.h" 31 #include "llvm/ADT/Optional.h" 32 #include <cstdint> 33 34 namespace clang { 35 36 class BlockDecl; 37 class CXXBoolLiteralExpr; 38 class CXXMethodDecl; 39 class CXXRecordDecl; 40 class DeclaratorDecl; 41 class FunctionDecl; 42 class LocationContext; 43 class StackFrameContext; 44 class Stmt; 45 46 namespace ento { 47 48 class ConditionTruthVal; 49 class ProgramStateManager; 50 class StoreRef; 51 52 class SValBuilder { 53 virtual void anchor(); 54 55 protected: 56 ASTContext &Context; 57 58 /// Manager of APSInt values. 59 BasicValueFactory BasicVals; 60 61 /// Manages the creation of symbols. 62 SymbolManager SymMgr; 63 64 /// Manages the creation of memory regions. 65 MemRegionManager MemMgr; 66 67 ProgramStateManager &StateMgr; 68 69 /// The scalar type to use for array indices. 70 const QualType ArrayIndexTy; 71 72 /// The width of the scalar type used for array indices. 73 const unsigned ArrayIndexWidth; 74 75 virtual SVal evalCastFromNonLoc(NonLoc val, QualType castTy) = 0; 76 virtual SVal evalCastFromLoc(Loc val, QualType castTy) = 0; 77 78 public: 79 // FIXME: Make these protected again once RegionStoreManager correctly 80 // handles loads from different bound value types. 81 virtual SVal dispatchCast(SVal val, QualType castTy) = 0; 82 83 public: 84 SValBuilder(llvm::BumpPtrAllocator &alloc, ASTContext &context, 85 ProgramStateManager &stateMgr) 86 : Context(context), BasicVals(context, alloc), 87 SymMgr(context, BasicVals, alloc), MemMgr(context, alloc), 88 StateMgr(stateMgr), ArrayIndexTy(context.LongLongTy), 89 ArrayIndexWidth(context.getTypeSize(ArrayIndexTy)) {} 90 91 virtual ~SValBuilder() = default; 92 93 bool haveSameType(const SymExpr *Sym1, const SymExpr *Sym2) { 94 return haveSameType(Sym1->getType(), Sym2->getType()); 95 } 96 97 bool haveSameType(QualType Ty1, QualType Ty2) { 98 // FIXME: Remove the second disjunct when we support symbolic 99 // truncation/extension. 100 return (Context.getCanonicalType(Ty1) == Context.getCanonicalType(Ty2) || 101 (Ty1->isIntegralOrEnumerationType() && 102 Ty2->isIntegralOrEnumerationType())); 103 } 104 105 SVal evalCast(SVal val, QualType castTy, QualType originalType); 106 107 // Handles casts of type CK_IntegralCast. 108 SVal evalIntegralCast(ProgramStateRef state, SVal val, QualType castTy, 109 QualType originalType); 110 111 virtual SVal evalMinus(NonLoc val) = 0; 112 113 virtual SVal evalComplement(NonLoc val) = 0; 114 115 /// Create a new value which represents a binary expression with two non- 116 /// location operands. 117 virtual SVal evalBinOpNN(ProgramStateRef state, BinaryOperator::Opcode op, 118 NonLoc lhs, NonLoc rhs, QualType resultTy) = 0; 119 120 /// Create a new value which represents a binary expression with two memory 121 /// location operands. 122 virtual SVal evalBinOpLL(ProgramStateRef state, BinaryOperator::Opcode op, 123 Loc lhs, Loc rhs, QualType resultTy) = 0; 124 125 /// Create a new value which represents a binary expression with a memory 126 /// location and non-location operands. For example, this would be used to 127 /// evaluate a pointer arithmetic operation. 128 virtual SVal evalBinOpLN(ProgramStateRef state, BinaryOperator::Opcode op, 129 Loc lhs, NonLoc rhs, QualType resultTy) = 0; 130 131 /// Evaluates a given SVal. If the SVal has only one possible (integer) value, 132 /// that value is returned. Otherwise, returns NULL. 133 virtual const llvm::APSInt *getKnownValue(ProgramStateRef state, SVal val) = 0; 134 135 /// Simplify symbolic expressions within a given SVal. Return an SVal 136 /// that represents the same value, but is hopefully easier to work with 137 /// than the original SVal. 138 virtual SVal simplifySVal(ProgramStateRef State, SVal Val) = 0; 139 140 /// Constructs a symbolic expression for two non-location values. 141 SVal makeSymExprValNN(BinaryOperator::Opcode op, 142 NonLoc lhs, NonLoc rhs, QualType resultTy); 143 144 SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op, 145 SVal lhs, SVal rhs, QualType type); 146 147 /// \return Whether values in \p lhs and \p rhs are equal at \p state. 148 ConditionTruthVal areEqual(ProgramStateRef state, SVal lhs, SVal rhs); 149 150 SVal evalEQ(ProgramStateRef state, SVal lhs, SVal rhs); 151 152 DefinedOrUnknownSVal evalEQ(ProgramStateRef state, DefinedOrUnknownSVal lhs, 153 DefinedOrUnknownSVal rhs); 154 155 ASTContext &getContext() { return Context; } 156 const ASTContext &getContext() const { return Context; } 157 158 ProgramStateManager &getStateManager() { return StateMgr; } 159 160 QualType getConditionType() const { 161 return Context.getLangOpts().CPlusPlus ? Context.BoolTy : Context.IntTy; 162 } 163 164 QualType getArrayIndexType() const { 165 return ArrayIndexTy; 166 } 167 168 BasicValueFactory &getBasicValueFactory() { return BasicVals; } 169 const BasicValueFactory &getBasicValueFactory() const { return BasicVals; } 170 171 SymbolManager &getSymbolManager() { return SymMgr; } 172 const SymbolManager &getSymbolManager() const { return SymMgr; } 173 174 MemRegionManager &getRegionManager() { return MemMgr; } 175 const MemRegionManager &getRegionManager() const { return MemMgr; } 176 177 // Forwarding methods to SymbolManager. 178 179 const SymbolConjured* conjureSymbol(const Stmt *stmt, 180 const LocationContext *LCtx, 181 QualType type, 182 unsigned visitCount, 183 const void *symbolTag = nullptr) { 184 return SymMgr.conjureSymbol(stmt, LCtx, type, visitCount, symbolTag); 185 } 186 187 const SymbolConjured* conjureSymbol(const Expr *expr, 188 const LocationContext *LCtx, 189 unsigned visitCount, 190 const void *symbolTag = nullptr) { 191 return SymMgr.conjureSymbol(expr, LCtx, visitCount, symbolTag); 192 } 193 194 /// Construct an SVal representing '0' for the specified type. 195 DefinedOrUnknownSVal makeZeroVal(QualType type); 196 197 /// Make a unique symbol for value of region. 198 DefinedOrUnknownSVal getRegionValueSymbolVal(const TypedValueRegion *region); 199 200 /// Create a new symbol with a unique 'name'. 201 /// 202 /// We resort to conjured symbols when we cannot construct a derived symbol. 203 /// The advantage of symbols derived/built from other symbols is that we 204 /// preserve the relation between related(or even equivalent) expressions, so 205 /// conjured symbols should be used sparingly. 206 DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag, 207 const Expr *expr, 208 const LocationContext *LCtx, 209 unsigned count); 210 DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag, 211 const Expr *expr, 212 const LocationContext *LCtx, 213 QualType type, 214 unsigned count); 215 DefinedOrUnknownSVal conjureSymbolVal(const Stmt *stmt, 216 const LocationContext *LCtx, 217 QualType type, 218 unsigned visitCount); 219 220 /// Conjure a symbol representing heap allocated memory region. 221 /// 222 /// Note, the expression should represent a location. 223 DefinedOrUnknownSVal getConjuredHeapSymbolVal(const Expr *E, 224 const LocationContext *LCtx, 225 unsigned Count); 226 227 DefinedOrUnknownSVal getDerivedRegionValueSymbolVal( 228 SymbolRef parentSymbol, const TypedValueRegion *region); 229 230 DefinedSVal getMetadataSymbolVal(const void *symbolTag, 231 const MemRegion *region, 232 const Expr *expr, QualType type, 233 const LocationContext *LCtx, 234 unsigned count); 235 236 DefinedSVal getMemberPointer(const DeclaratorDecl *DD); 237 238 DefinedSVal getFunctionPointer(const FunctionDecl *func); 239 240 DefinedSVal getBlockPointer(const BlockDecl *block, CanQualType locTy, 241 const LocationContext *locContext, 242 unsigned blockCount); 243 244 /// Returns the value of \p E, if it can be determined in a non-path-sensitive 245 /// manner. 246 /// 247 /// If \p E is not a constant or cannot be modeled, returns \c None. 248 Optional<SVal> getConstantVal(const Expr *E); 249 250 NonLoc makeCompoundVal(QualType type, llvm::ImmutableList<SVal> vals) { 251 return nonloc::CompoundVal(BasicVals.getCompoundValData(type, vals)); 252 } 253 254 NonLoc makeLazyCompoundVal(const StoreRef &store, 255 const TypedValueRegion *region) { 256 return nonloc::LazyCompoundVal( 257 BasicVals.getLazyCompoundValData(store, region)); 258 } 259 260 NonLoc makePointerToMember(const DeclaratorDecl *DD) { 261 return nonloc::PointerToMember(DD); 262 } 263 264 NonLoc makePointerToMember(const PointerToMemberData *PTMD) { 265 return nonloc::PointerToMember(PTMD); 266 } 267 268 NonLoc makeZeroArrayIndex() { 269 return nonloc::ConcreteInt(BasicVals.getValue(0, ArrayIndexTy)); 270 } 271 272 NonLoc makeArrayIndex(uint64_t idx) { 273 return nonloc::ConcreteInt(BasicVals.getValue(idx, ArrayIndexTy)); 274 } 275 276 SVal convertToArrayIndex(SVal val); 277 278 nonloc::ConcreteInt makeIntVal(const IntegerLiteral* integer) { 279 return nonloc::ConcreteInt( 280 BasicVals.getValue(integer->getValue(), 281 integer->getType()->isUnsignedIntegerOrEnumerationType())); 282 } 283 284 nonloc::ConcreteInt makeBoolVal(const ObjCBoolLiteralExpr *boolean) { 285 return makeTruthVal(boolean->getValue(), boolean->getType()); 286 } 287 288 nonloc::ConcreteInt makeBoolVal(const CXXBoolLiteralExpr *boolean); 289 290 nonloc::ConcreteInt makeIntVal(const llvm::APSInt& integer) { 291 return nonloc::ConcreteInt(BasicVals.getValue(integer)); 292 } 293 294 loc::ConcreteInt makeIntLocVal(const llvm::APSInt &integer) { 295 return loc::ConcreteInt(BasicVals.getValue(integer)); 296 } 297 298 NonLoc makeIntVal(const llvm::APInt& integer, bool isUnsigned) { 299 return nonloc::ConcreteInt(BasicVals.getValue(integer, isUnsigned)); 300 } 301 302 DefinedSVal makeIntVal(uint64_t integer, QualType type) { 303 if (Loc::isLocType(type)) 304 return loc::ConcreteInt(BasicVals.getValue(integer, type)); 305 306 return nonloc::ConcreteInt(BasicVals.getValue(integer, type)); 307 } 308 309 NonLoc makeIntVal(uint64_t integer, bool isUnsigned) { 310 return nonloc::ConcreteInt(BasicVals.getIntValue(integer, isUnsigned)); 311 } 312 313 NonLoc makeIntValWithPtrWidth(uint64_t integer, bool isUnsigned) { 314 return nonloc::ConcreteInt( 315 BasicVals.getIntWithPtrWidth(integer, isUnsigned)); 316 } 317 318 NonLoc makeLocAsInteger(Loc loc, unsigned bits) { 319 return nonloc::LocAsInteger(BasicVals.getPersistentSValWithData(loc, bits)); 320 } 321 322 NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op, 323 const llvm::APSInt& rhs, QualType type); 324 325 NonLoc makeNonLoc(const llvm::APSInt& rhs, BinaryOperator::Opcode op, 326 const SymExpr *lhs, QualType type); 327 328 NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op, 329 const SymExpr *rhs, QualType type); 330 331 /// Create a NonLoc value for cast. 332 NonLoc makeNonLoc(const SymExpr *operand, QualType fromTy, QualType toTy); 333 334 nonloc::ConcreteInt makeTruthVal(bool b, QualType type) { 335 return nonloc::ConcreteInt(BasicVals.getTruthValue(b, type)); 336 } 337 338 nonloc::ConcreteInt makeTruthVal(bool b) { 339 return nonloc::ConcreteInt(BasicVals.getTruthValue(b)); 340 } 341 342 /// Create NULL pointer, with proper pointer bit-width for given address 343 /// space. 344 /// \param type pointer type. 345 Loc makeNullWithType(QualType type) { 346 return loc::ConcreteInt(BasicVals.getZeroWithTypeSize(type)); 347 } 348 349 Loc makeNull() { 350 return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth()); 351 } 352 353 Loc makeLoc(SymbolRef sym) { 354 return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym)); 355 } 356 357 Loc makeLoc(const MemRegion* region) { 358 return loc::MemRegionVal(region); 359 } 360 361 Loc makeLoc(const AddrLabelExpr *expr) { 362 return loc::GotoLabel(expr->getLabel()); 363 } 364 365 Loc makeLoc(const llvm::APSInt& integer) { 366 return loc::ConcreteInt(BasicVals.getValue(integer)); 367 } 368 369 /// Make an SVal that represents the given symbol. This follows the convention 370 /// of representing Loc-type symbols (symbolic pointers and references) 371 /// as Loc values wrapping the symbol rather than as plain symbol values. 372 SVal makeSymbolVal(SymbolRef Sym) { 373 if (Loc::isLocType(Sym->getType())) 374 return makeLoc(Sym); 375 return nonloc::SymbolVal(Sym); 376 } 377 378 /// Return a memory region for the 'this' object reference. 379 loc::MemRegionVal getCXXThis(const CXXMethodDecl *D, 380 const StackFrameContext *SFC); 381 382 /// Return a memory region for the 'this' object reference. 383 loc::MemRegionVal getCXXThis(const CXXRecordDecl *D, 384 const StackFrameContext *SFC); 385 }; 386 387 SValBuilder* createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc, 388 ASTContext &context, 389 ProgramStateManager &stateMgr); 390 391 } // namespace ento 392 393 } // namespace clang 394 395 #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SVALBUILDER_H 396