1 //= RValues.cpp - Abstract RValues for Path-Sens. Value Tracking -*- 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 SVal, Loc, and NonLoc, classes that represent 11 // abstract r-values for use with path-sensitive value tracking. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h" 16 #include "clang/AST/ExprObjC.h" 17 #include "clang/Basic/IdentifierTable.h" 18 using namespace clang; 19 using namespace ento; 20 using llvm::APSInt; 21 22 //===----------------------------------------------------------------------===// 23 // Symbol iteration within an SVal. 24 //===----------------------------------------------------------------------===// 25 26 27 //===----------------------------------------------------------------------===// 28 // Utility methods. 29 //===----------------------------------------------------------------------===// 30 31 bool SVal::hasConjuredSymbol() const { 32 if (const nonloc::SymbolVal* SV = dyn_cast<nonloc::SymbolVal>(this)) { 33 SymbolRef sym = SV->getSymbol(); 34 if (isa<SymbolConjured>(sym)) 35 return true; 36 } 37 38 if (const loc::MemRegionVal *RV = dyn_cast<loc::MemRegionVal>(this)) { 39 const MemRegion *R = RV->getRegion(); 40 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) { 41 SymbolRef sym = SR->getSymbol(); 42 if (isa<SymbolConjured>(sym)) 43 return true; 44 } 45 } 46 47 return false; 48 } 49 50 const FunctionDecl *SVal::getAsFunctionDecl() const { 51 if (const loc::MemRegionVal* X = dyn_cast<loc::MemRegionVal>(this)) { 52 const MemRegion* R = X->getRegion(); 53 if (const FunctionTextRegion *CTR = R->getAs<FunctionTextRegion>()) 54 return CTR->getDecl(); 55 } 56 57 return NULL; 58 } 59 60 /// getAsLocSymbol - If this SVal is a location (subclasses Loc) and 61 /// wraps a symbol, return that SymbolRef. Otherwise return 0. 62 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion? 63 SymbolRef SVal::getAsLocSymbol() const { 64 if (const nonloc::LocAsInteger *X = dyn_cast<nonloc::LocAsInteger>(this)) 65 return X->getLoc().getAsLocSymbol(); 66 67 if (const loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(this)) { 68 const MemRegion *R = X->stripCasts(); 69 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(R)) 70 return SymR->getSymbol(); 71 } 72 return NULL; 73 } 74 75 /// Get the symbol in the SVal or its base region. 76 SymbolRef SVal::getLocSymbolInBase() const { 77 const loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(this); 78 79 if (!X) 80 return 0; 81 82 const MemRegion *R = X->getRegion(); 83 84 while (const SubRegion *SR = dyn_cast<SubRegion>(R)) { 85 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(SR)) 86 return SymR->getSymbol(); 87 else 88 R = SR->getSuperRegion(); 89 } 90 91 return 0; 92 } 93 94 /// getAsSymbol - If this Sval wraps a symbol return that SymbolRef. 95 /// Otherwise return 0. 96 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion? 97 SymbolRef SVal::getAsSymbol() const { 98 if (const nonloc::SymbolVal *X = dyn_cast<nonloc::SymbolVal>(this)) 99 return X->getSymbol(); 100 101 if (const nonloc::SymExprVal *X = dyn_cast<nonloc::SymExprVal>(this)) 102 if (SymbolRef Y = dyn_cast<SymbolData>(X->getSymbolicExpression())) 103 return Y; 104 105 return getAsLocSymbol(); 106 } 107 108 /// getAsSymbolicExpression - If this Sval wraps a symbolic expression then 109 /// return that expression. Otherwise return NULL. 110 const SymExpr *SVal::getAsSymbolicExpression() const { 111 if (const nonloc::SymExprVal *X = dyn_cast<nonloc::SymExprVal>(this)) 112 return X->getSymbolicExpression(); 113 114 return getAsSymbol(); 115 } 116 117 const MemRegion *SVal::getAsRegion() const { 118 if (const loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(this)) 119 return X->getRegion(); 120 121 if (const nonloc::LocAsInteger *X = dyn_cast<nonloc::LocAsInteger>(this)) { 122 return X->getLoc().getAsRegion(); 123 } 124 125 return 0; 126 } 127 128 const MemRegion *loc::MemRegionVal::stripCasts() const { 129 const MemRegion *R = getRegion(); 130 return R ? R->StripCasts() : NULL; 131 } 132 133 bool SVal::symbol_iterator::operator==(const symbol_iterator &X) const { 134 return itr == X.itr; 135 } 136 137 bool SVal::symbol_iterator::operator!=(const symbol_iterator &X) const { 138 return itr != X.itr; 139 } 140 141 SVal::symbol_iterator::symbol_iterator(const SymExpr *SE) { 142 itr.push_back(SE); 143 while (!isa<SymbolData>(itr.back())) expand(); 144 } 145 146 SVal::symbol_iterator &SVal::symbol_iterator::operator++() { 147 assert(!itr.empty() && "attempting to iterate on an 'end' iterator"); 148 assert(isa<SymbolData>(itr.back())); 149 itr.pop_back(); 150 if (!itr.empty()) 151 while (!isa<SymbolData>(itr.back())) expand(); 152 return *this; 153 } 154 155 SymbolRef SVal::symbol_iterator::operator*() { 156 assert(!itr.empty() && "attempting to dereference an 'end' iterator"); 157 return cast<SymbolData>(itr.back()); 158 } 159 160 void SVal::symbol_iterator::expand() { 161 const SymExpr *SE = itr.back(); 162 itr.pop_back(); 163 164 if (const SymIntExpr *SIE = dyn_cast<SymIntExpr>(SE)) { 165 itr.push_back(SIE->getLHS()); 166 return; 167 } 168 else if (const SymSymExpr *SSE = dyn_cast<SymSymExpr>(SE)) { 169 itr.push_back(SSE->getLHS()); 170 itr.push_back(SSE->getRHS()); 171 return; 172 } 173 174 llvm_unreachable("unhandled expansion case"); 175 } 176 177 const void *nonloc::LazyCompoundVal::getStore() const { 178 return static_cast<const LazyCompoundValData*>(Data)->getStore(); 179 } 180 181 const TypedRegion *nonloc::LazyCompoundVal::getRegion() const { 182 return static_cast<const LazyCompoundValData*>(Data)->getRegion(); 183 } 184 185 //===----------------------------------------------------------------------===// 186 // Other Iterators. 187 //===----------------------------------------------------------------------===// 188 189 nonloc::CompoundVal::iterator nonloc::CompoundVal::begin() const { 190 return getValue()->begin(); 191 } 192 193 nonloc::CompoundVal::iterator nonloc::CompoundVal::end() const { 194 return getValue()->end(); 195 } 196 197 //===----------------------------------------------------------------------===// 198 // Useful predicates. 199 //===----------------------------------------------------------------------===// 200 201 bool SVal::isConstant() const { 202 return isa<nonloc::ConcreteInt>(this) || isa<loc::ConcreteInt>(this); 203 } 204 205 bool SVal::isConstant(int I) const { 206 if (isa<loc::ConcreteInt>(*this)) 207 return cast<loc::ConcreteInt>(*this).getValue() == I; 208 else if (isa<nonloc::ConcreteInt>(*this)) 209 return cast<nonloc::ConcreteInt>(*this).getValue() == I; 210 else 211 return false; 212 } 213 214 bool SVal::isZeroConstant() const { 215 return isConstant(0); 216 } 217 218 219 //===----------------------------------------------------------------------===// 220 // Transfer function dispatch for Non-Locs. 221 //===----------------------------------------------------------------------===// 222 223 SVal nonloc::ConcreteInt::evalBinOp(SValBuilder &svalBuilder, 224 BinaryOperator::Opcode Op, 225 const nonloc::ConcreteInt& R) const { 226 const llvm::APSInt* X = 227 svalBuilder.getBasicValueFactory().evalAPSInt(Op, getValue(), R.getValue()); 228 229 if (X) 230 return nonloc::ConcreteInt(*X); 231 else 232 return UndefinedVal(); 233 } 234 235 nonloc::ConcreteInt 236 nonloc::ConcreteInt::evalComplement(SValBuilder &svalBuilder) const { 237 return svalBuilder.makeIntVal(~getValue()); 238 } 239 240 nonloc::ConcreteInt 241 nonloc::ConcreteInt::evalMinus(SValBuilder &svalBuilder) const { 242 return svalBuilder.makeIntVal(-getValue()); 243 } 244 245 //===----------------------------------------------------------------------===// 246 // Transfer function dispatch for Locs. 247 //===----------------------------------------------------------------------===// 248 249 SVal loc::ConcreteInt::evalBinOp(BasicValueFactory& BasicVals, 250 BinaryOperator::Opcode Op, 251 const loc::ConcreteInt& R) const { 252 253 assert (Op == BO_Add || Op == BO_Sub || 254 (Op >= BO_LT && Op <= BO_NE)); 255 256 const llvm::APSInt* X = BasicVals.evalAPSInt(Op, getValue(), R.getValue()); 257 258 if (X) 259 return loc::ConcreteInt(*X); 260 else 261 return UndefinedVal(); 262 } 263 264 //===----------------------------------------------------------------------===// 265 // Pretty-Printing. 266 //===----------------------------------------------------------------------===// 267 268 void SVal::dump() const { dumpToStream(llvm::errs()); } 269 270 void SVal::dumpToStream(raw_ostream &os) const { 271 switch (getBaseKind()) { 272 case UnknownKind: 273 os << "Unknown"; 274 break; 275 case NonLocKind: 276 cast<NonLoc>(this)->dumpToStream(os); 277 break; 278 case LocKind: 279 cast<Loc>(this)->dumpToStream(os); 280 break; 281 case UndefinedKind: 282 os << "Undefined"; 283 break; 284 default: 285 assert (false && "Invalid SVal."); 286 } 287 } 288 289 void NonLoc::dumpToStream(raw_ostream &os) const { 290 switch (getSubKind()) { 291 case nonloc::ConcreteIntKind: { 292 const nonloc::ConcreteInt& C = *cast<nonloc::ConcreteInt>(this); 293 if (C.getValue().isUnsigned()) 294 os << C.getValue().getZExtValue(); 295 else 296 os << C.getValue().getSExtValue(); 297 os << ' ' << (C.getValue().isUnsigned() ? 'U' : 'S') 298 << C.getValue().getBitWidth() << 'b'; 299 break; 300 } 301 case nonloc::SymbolValKind: 302 os << '$' << cast<nonloc::SymbolVal>(this)->getSymbol(); 303 break; 304 case nonloc::SymExprValKind: { 305 const nonloc::SymExprVal& C = *cast<nonloc::SymExprVal>(this); 306 const SymExpr *SE = C.getSymbolicExpression(); 307 os << SE; 308 break; 309 } 310 case nonloc::LocAsIntegerKind: { 311 const nonloc::LocAsInteger& C = *cast<nonloc::LocAsInteger>(this); 312 os << C.getLoc() << " [as " << C.getNumBits() << " bit integer]"; 313 break; 314 } 315 case nonloc::CompoundValKind: { 316 const nonloc::CompoundVal& C = *cast<nonloc::CompoundVal>(this); 317 os << "compoundVal{"; 318 bool first = true; 319 for (nonloc::CompoundVal::iterator I=C.begin(), E=C.end(); I!=E; ++I) { 320 if (first) { 321 os << ' '; first = false; 322 } 323 else 324 os << ", "; 325 326 (*I).dumpToStream(os); 327 } 328 os << "}"; 329 break; 330 } 331 case nonloc::LazyCompoundValKind: { 332 const nonloc::LazyCompoundVal &C = *cast<nonloc::LazyCompoundVal>(this); 333 os << "lazyCompoundVal{" << const_cast<void *>(C.getStore()) 334 << ',' << C.getRegion() 335 << '}'; 336 break; 337 } 338 default: 339 assert (false && "Pretty-printed not implemented for this NonLoc."); 340 break; 341 } 342 } 343 344 void Loc::dumpToStream(raw_ostream &os) const { 345 switch (getSubKind()) { 346 case loc::ConcreteIntKind: 347 os << cast<loc::ConcreteInt>(this)->getValue().getZExtValue() << " (Loc)"; 348 break; 349 case loc::GotoLabelKind: 350 os << "&&" << cast<loc::GotoLabel>(this)->getLabel()->getName(); 351 break; 352 case loc::MemRegionKind: 353 os << '&' << cast<loc::MemRegionVal>(this)->getRegion()->getString(); 354 break; 355 case loc::ObjCPropRefKind: { 356 const ObjCPropertyRefExpr *E = cast<loc::ObjCPropRef>(this)->getPropRefExpr(); 357 os << "objc-prop{"; 358 if (E->isSuperReceiver()) 359 os << "super."; 360 else if (E->getBase()) 361 os << "<base>."; 362 363 if (E->isImplicitProperty()) 364 os << E->getImplicitPropertyGetter()->getSelector().getAsString(); 365 else 366 os << E->getExplicitProperty()->getName(); 367 368 os << "}"; 369 break; 370 } 371 default: 372 llvm_unreachable("Pretty-printing not implemented for this Loc."); 373 } 374 } 375