1 //===-- SVals.cpp - Abstract RValues for Path-Sens. Value Tracking --------===// 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 SVal, Loc, and NonLoc, classes that represent 10 // abstract r-values for use with path-sensitive value tracking. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h" 15 #include "clang/AST/Decl.h" 16 #include "clang/AST/DeclCXX.h" 17 #include "clang/AST/Expr.h" 18 #include "clang/AST/Type.h" 19 #include "clang/Basic/JsonSupport.h" 20 #include "clang/Basic/LLVM.h" 21 #include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h" 22 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h" 23 #include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h" 24 #include "clang/StaticAnalyzer/Core/PathSensitive/SymExpr.h" 25 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" 26 #include "llvm/ADT/Optional.h" 27 #include "llvm/Support/Casting.h" 28 #include "llvm/Support/Compiler.h" 29 #include "llvm/Support/ErrorHandling.h" 30 #include "llvm/Support/raw_ostream.h" 31 #include <cassert> 32 33 using namespace clang; 34 using namespace ento; 35 36 //===----------------------------------------------------------------------===// 37 // Symbol iteration within an SVal. 38 //===----------------------------------------------------------------------===// 39 40 //===----------------------------------------------------------------------===// 41 // Utility methods. 42 //===----------------------------------------------------------------------===// 43 44 bool SVal::hasConjuredSymbol() const { 45 if (Optional<nonloc::SymbolVal> SV = getAs<nonloc::SymbolVal>()) { 46 SymbolRef sym = SV->getSymbol(); 47 if (isa<SymbolConjured>(sym)) 48 return true; 49 } 50 51 if (Optional<loc::MemRegionVal> RV = getAs<loc::MemRegionVal>()) { 52 const MemRegion *R = RV->getRegion(); 53 if (const auto *SR = dyn_cast<SymbolicRegion>(R)) { 54 SymbolRef sym = SR->getSymbol(); 55 if (isa<SymbolConjured>(sym)) 56 return true; 57 } 58 } 59 60 return false; 61 } 62 63 const FunctionDecl *SVal::getAsFunctionDecl() const { 64 if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) { 65 const MemRegion* R = X->getRegion(); 66 if (const FunctionCodeRegion *CTR = R->getAs<FunctionCodeRegion>()) 67 if (const auto *FD = dyn_cast<FunctionDecl>(CTR->getDecl())) 68 return FD; 69 } 70 71 if (auto X = getAs<nonloc::PointerToMember>()) { 72 if (const auto *MD = dyn_cast_or_null<CXXMethodDecl>(X->getDecl())) 73 return MD; 74 } 75 return nullptr; 76 } 77 78 /// If this SVal is a location (subclasses Loc) and wraps a symbol, 79 /// return that SymbolRef. Otherwise return 0. 80 /// 81 /// Implicit casts (ex: void* -> char*) can turn Symbolic region into Element 82 /// region. If that is the case, gets the underlining region. 83 /// When IncludeBaseRegions is set to true and the SubRegion is non-symbolic, 84 /// the first symbolic parent region is returned. 85 SymbolRef SVal::getAsLocSymbol(bool IncludeBaseRegions) const { 86 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion? 87 if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>()) 88 return X->getLoc().getAsLocSymbol(IncludeBaseRegions); 89 90 if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) { 91 const MemRegion *R = X->getRegion(); 92 if (const SymbolicRegion *SymR = IncludeBaseRegions ? 93 R->getSymbolicBase() : 94 dyn_cast<SymbolicRegion>(R->StripCasts())) 95 return SymR->getSymbol(); 96 } 97 return nullptr; 98 } 99 100 /// Get the symbol in the SVal or its base region. 101 SymbolRef SVal::getLocSymbolInBase() const { 102 Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>(); 103 104 if (!X) 105 return nullptr; 106 107 const MemRegion *R = X->getRegion(); 108 109 while (const auto *SR = dyn_cast<SubRegion>(R)) { 110 if (const auto *SymR = dyn_cast<SymbolicRegion>(SR)) 111 return SymR->getSymbol(); 112 else 113 R = SR->getSuperRegion(); 114 } 115 116 return nullptr; 117 } 118 119 // TODO: The next 3 functions have to be simplified. 120 121 /// If this SVal wraps a symbol return that SymbolRef. 122 /// Otherwise, return 0. 123 /// 124 /// Casts are ignored during lookup. 125 /// \param IncludeBaseRegions The boolean that controls whether the search 126 /// should continue to the base regions if the region is not symbolic. 127 SymbolRef SVal::getAsSymbol(bool IncludeBaseRegions) const { 128 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion? 129 if (Optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>()) 130 return X->getSymbol(); 131 132 return getAsLocSymbol(IncludeBaseRegions); 133 } 134 135 /// getAsSymbolicExpression - If this Sval wraps a symbolic expression then 136 /// return that expression. Otherwise return NULL. 137 const SymExpr *SVal::getAsSymbolicExpression() const { 138 if (Optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>()) 139 return X->getSymbol(); 140 141 return getAsSymbol(); 142 } 143 144 const SymExpr* SVal::getAsSymExpr() const { 145 const SymExpr* Sym = getAsSymbol(); 146 if (!Sym) 147 Sym = getAsSymbolicExpression(); 148 return Sym; 149 } 150 151 const MemRegion *SVal::getAsRegion() const { 152 if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) 153 return X->getRegion(); 154 155 if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>()) 156 return X->getLoc().getAsRegion(); 157 158 return nullptr; 159 } 160 161 const MemRegion *loc::MemRegionVal::stripCasts(bool StripBaseCasts) const { 162 const MemRegion *R = getRegion(); 163 return R ? R->StripCasts(StripBaseCasts) : nullptr; 164 } 165 166 const void *nonloc::LazyCompoundVal::getStore() const { 167 return static_cast<const LazyCompoundValData*>(Data)->getStore(); 168 } 169 170 const TypedValueRegion *nonloc::LazyCompoundVal::getRegion() const { 171 return static_cast<const LazyCompoundValData*>(Data)->getRegion(); 172 } 173 174 bool nonloc::PointerToMember::isNullMemberPointer() const { 175 return getPTMData().isNull(); 176 } 177 178 const DeclaratorDecl *nonloc::PointerToMember::getDecl() const { 179 const auto PTMD = this->getPTMData(); 180 if (PTMD.isNull()) 181 return nullptr; 182 183 const DeclaratorDecl *DD = nullptr; 184 if (PTMD.is<const DeclaratorDecl *>()) 185 DD = PTMD.get<const DeclaratorDecl *>(); 186 else 187 DD = PTMD.get<const PointerToMemberData *>()->getDeclaratorDecl(); 188 189 return DD; 190 } 191 192 //===----------------------------------------------------------------------===// 193 // Other Iterators. 194 //===----------------------------------------------------------------------===// 195 196 nonloc::CompoundVal::iterator nonloc::CompoundVal::begin() const { 197 return getValue()->begin(); 198 } 199 200 nonloc::CompoundVal::iterator nonloc::CompoundVal::end() const { 201 return getValue()->end(); 202 } 203 204 nonloc::PointerToMember::iterator nonloc::PointerToMember::begin() const { 205 const PTMDataType PTMD = getPTMData(); 206 if (PTMD.is<const DeclaratorDecl *>()) 207 return {}; 208 return PTMD.get<const PointerToMemberData *>()->begin(); 209 } 210 211 nonloc::PointerToMember::iterator nonloc::PointerToMember::end() const { 212 const PTMDataType PTMD = getPTMData(); 213 if (PTMD.is<const DeclaratorDecl *>()) 214 return {}; 215 return PTMD.get<const PointerToMemberData *>()->end(); 216 } 217 218 //===----------------------------------------------------------------------===// 219 // Useful predicates. 220 //===----------------------------------------------------------------------===// 221 222 bool SVal::isConstant() const { 223 return getAs<nonloc::ConcreteInt>() || getAs<loc::ConcreteInt>(); 224 } 225 226 bool SVal::isConstant(int I) const { 227 if (Optional<loc::ConcreteInt> LV = getAs<loc::ConcreteInt>()) 228 return LV->getValue() == I; 229 if (Optional<nonloc::ConcreteInt> NV = getAs<nonloc::ConcreteInt>()) 230 return NV->getValue() == I; 231 return false; 232 } 233 234 bool SVal::isZeroConstant() const { 235 return isConstant(0); 236 } 237 238 //===----------------------------------------------------------------------===// 239 // Transfer function dispatch for Non-Locs. 240 //===----------------------------------------------------------------------===// 241 242 SVal nonloc::ConcreteInt::evalBinOp(SValBuilder &svalBuilder, 243 BinaryOperator::Opcode Op, 244 const nonloc::ConcreteInt& R) const { 245 const llvm::APSInt* X = 246 svalBuilder.getBasicValueFactory().evalAPSInt(Op, getValue(), R.getValue()); 247 248 if (X) 249 return nonloc::ConcreteInt(*X); 250 else 251 return UndefinedVal(); 252 } 253 254 nonloc::ConcreteInt 255 nonloc::ConcreteInt::evalComplement(SValBuilder &svalBuilder) const { 256 return svalBuilder.makeIntVal(~getValue()); 257 } 258 259 nonloc::ConcreteInt 260 nonloc::ConcreteInt::evalMinus(SValBuilder &svalBuilder) const { 261 return svalBuilder.makeIntVal(-getValue()); 262 } 263 264 //===----------------------------------------------------------------------===// 265 // Transfer function dispatch for Locs. 266 //===----------------------------------------------------------------------===// 267 268 SVal loc::ConcreteInt::evalBinOp(BasicValueFactory& BasicVals, 269 BinaryOperator::Opcode Op, 270 const loc::ConcreteInt& R) const { 271 assert(BinaryOperator::isComparisonOp(Op) || Op == BO_Sub); 272 273 const llvm::APSInt *X = BasicVals.evalAPSInt(Op, getValue(), R.getValue()); 274 275 if (X) 276 return nonloc::ConcreteInt(*X); 277 else 278 return UndefinedVal(); 279 } 280 281 //===----------------------------------------------------------------------===// 282 // Pretty-Printing. 283 //===----------------------------------------------------------------------===// 284 285 LLVM_DUMP_METHOD void SVal::dump() const { dumpToStream(llvm::errs()); } 286 287 void SVal::printJson(raw_ostream &Out, bool AddQuotes) const { 288 std::string Buf; 289 llvm::raw_string_ostream TempOut(Buf); 290 291 dumpToStream(TempOut); 292 293 Out << JsonFormat(TempOut.str(), AddQuotes); 294 } 295 296 void SVal::dumpToStream(raw_ostream &os) const { 297 switch (getBaseKind()) { 298 case UnknownValKind: 299 os << "Unknown"; 300 break; 301 case NonLocKind: 302 castAs<NonLoc>().dumpToStream(os); 303 break; 304 case LocKind: 305 castAs<Loc>().dumpToStream(os); 306 break; 307 case UndefinedValKind: 308 os << "Undefined"; 309 break; 310 } 311 } 312 313 void NonLoc::dumpToStream(raw_ostream &os) const { 314 switch (getSubKind()) { 315 case nonloc::ConcreteIntKind: { 316 const auto &Value = castAs<nonloc::ConcreteInt>().getValue(); 317 os << Value << ' ' << (Value.isSigned() ? 'S' : 'U') 318 << Value.getBitWidth() << 'b'; 319 break; 320 } 321 case nonloc::SymbolValKind: 322 os << castAs<nonloc::SymbolVal>().getSymbol(); 323 break; 324 325 case nonloc::LocAsIntegerKind: { 326 const nonloc::LocAsInteger& C = castAs<nonloc::LocAsInteger>(); 327 os << C.getLoc() << " [as " << C.getNumBits() << " bit integer]"; 328 break; 329 } 330 case nonloc::CompoundValKind: { 331 const nonloc::CompoundVal& C = castAs<nonloc::CompoundVal>(); 332 os << "compoundVal{"; 333 bool first = true; 334 for (const auto &I : C) { 335 if (first) { 336 os << ' '; first = false; 337 } 338 else 339 os << ", "; 340 341 I.dumpToStream(os); 342 } 343 os << "}"; 344 break; 345 } 346 case nonloc::LazyCompoundValKind: { 347 const nonloc::LazyCompoundVal &C = castAs<nonloc::LazyCompoundVal>(); 348 os << "lazyCompoundVal{" << const_cast<void *>(C.getStore()) 349 << ',' << C.getRegion() 350 << '}'; 351 break; 352 } 353 case nonloc::PointerToMemberKind: { 354 os << "pointerToMember{"; 355 const nonloc::PointerToMember &CastRes = 356 castAs<nonloc::PointerToMember>(); 357 if (CastRes.getDecl()) 358 os << "|" << CastRes.getDecl()->getQualifiedNameAsString() << "|"; 359 bool first = true; 360 for (const auto &I : CastRes) { 361 if (first) { 362 os << ' '; first = false; 363 } 364 else 365 os << ", "; 366 367 os << (*I).getType().getAsString(); 368 } 369 370 os << '}'; 371 break; 372 } 373 default: 374 assert(false && "Pretty-printed not implemented for this NonLoc."); 375 break; 376 } 377 } 378 379 void Loc::dumpToStream(raw_ostream &os) const { 380 switch (getSubKind()) { 381 case loc::ConcreteIntKind: 382 os << castAs<loc::ConcreteInt>().getValue().getZExtValue() << " (Loc)"; 383 break; 384 case loc::GotoLabelKind: 385 os << "&&" << castAs<loc::GotoLabel>().getLabel()->getName(); 386 break; 387 case loc::MemRegionValKind: 388 os << '&' << castAs<loc::MemRegionVal>().getRegion()->getString(); 389 break; 390 default: 391 llvm_unreachable("Pretty-printing not implemented for this Loc."); 392 } 393 } 394