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#include "llvm/Support/raw_ostream.h" 19using namespace clang; 20using namespace ento; 21using llvm::APSInt; 22 23//===----------------------------------------------------------------------===// 24// Symbol iteration within an SVal. 25//===----------------------------------------------------------------------===// 26 27 28//===----------------------------------------------------------------------===// 29// Utility methods. 30//===----------------------------------------------------------------------===// 31 32bool SVal::hasConjuredSymbol() const { 33 if (Optional<nonloc::SymbolVal> SV = getAs<nonloc::SymbolVal>()) { 34 SymbolRef sym = SV->getSymbol(); 35 if (isa<SymbolConjured>(sym)) 36 return true; 37 } 38 39 if (Optional<loc::MemRegionVal> RV = getAs<loc::MemRegionVal>()) { 40 const MemRegion *R = RV->getRegion(); 41 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) { 42 SymbolRef sym = SR->getSymbol(); 43 if (isa<SymbolConjured>(sym)) 44 return true; 45 } 46 } 47 48 return false; 49} 50 51const FunctionDecl *SVal::getAsFunctionDecl() const { 52 if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) { 53 const MemRegion* R = X->getRegion(); 54 if (const FunctionTextRegion *CTR = R->getAs<FunctionTextRegion>()) 55 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CTR->getDecl())) 56 return FD; 57 } 58 59 return nullptr; 60} 61 62/// \brief If this SVal is a location (subclasses Loc) and wraps a symbol, 63/// return that SymbolRef. Otherwise return 0. 64/// 65/// Implicit casts (ex: void* -> char*) can turn Symbolic region into Element 66/// region. If that is the case, gets the underlining region. 67/// When IncludeBaseRegions is set to true and the SubRegion is non-symbolic, 68/// the first symbolic parent region is returned. 69SymbolRef SVal::getAsLocSymbol(bool IncludeBaseRegions) const { 70 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion? 71 if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>()) 72 return X->getLoc().getAsLocSymbol(); 73 74 if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) { 75 const MemRegion *R = X->getRegion(); 76 if (const SymbolicRegion *SymR = IncludeBaseRegions ? 77 R->getSymbolicBase() : 78 dyn_cast<SymbolicRegion>(R->StripCasts())) 79 return SymR->getSymbol(); 80 } 81 return nullptr; 82} 83 84/// Get the symbol in the SVal or its base region. 85SymbolRef SVal::getLocSymbolInBase() const { 86 Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>(); 87 88 if (!X) 89 return nullptr; 90 91 const MemRegion *R = X->getRegion(); 92 93 while (const SubRegion *SR = dyn_cast<SubRegion>(R)) { 94 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(SR)) 95 return SymR->getSymbol(); 96 else 97 R = SR->getSuperRegion(); 98 } 99 100 return nullptr; 101} 102 103// TODO: The next 3 functions have to be simplified. 104 105/// \brief If this SVal wraps a symbol return that SymbolRef. 106/// Otherwise, return 0. 107/// 108/// Casts are ignored during lookup. 109/// \param IncludeBaseRegions The boolean that controls whether the search 110/// should continue to the base regions if the region is not symbolic. 111SymbolRef SVal::getAsSymbol(bool IncludeBaseRegion) const { 112 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion? 113 if (Optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>()) 114 return X->getSymbol(); 115 116 return getAsLocSymbol(IncludeBaseRegion); 117} 118 119/// getAsSymbolicExpression - If this Sval wraps a symbolic expression then 120/// return that expression. Otherwise return NULL. 121const SymExpr *SVal::getAsSymbolicExpression() const { 122 if (Optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>()) 123 return X->getSymbol(); 124 125 return getAsSymbol(); 126} 127 128const SymExpr* SVal::getAsSymExpr() const { 129 const SymExpr* Sym = getAsSymbol(); 130 if (!Sym) 131 Sym = getAsSymbolicExpression(); 132 return Sym; 133} 134 135const MemRegion *SVal::getAsRegion() const { 136 if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) 137 return X->getRegion(); 138 139 if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>()) 140 return X->getLoc().getAsRegion(); 141 142 return nullptr; 143} 144 145const MemRegion *loc::MemRegionVal::stripCasts(bool StripBaseCasts) const { 146 const MemRegion *R = getRegion(); 147 return R ? R->StripCasts(StripBaseCasts) : nullptr; 148} 149 150const void *nonloc::LazyCompoundVal::getStore() const { 151 return static_cast<const LazyCompoundValData*>(Data)->getStore(); 152} 153 154const TypedValueRegion *nonloc::LazyCompoundVal::getRegion() const { 155 return static_cast<const LazyCompoundValData*>(Data)->getRegion(); 156} 157 158//===----------------------------------------------------------------------===// 159// Other Iterators. 160//===----------------------------------------------------------------------===// 161 162nonloc::CompoundVal::iterator nonloc::CompoundVal::begin() const { 163 return getValue()->begin(); 164} 165 166nonloc::CompoundVal::iterator nonloc::CompoundVal::end() const { 167 return getValue()->end(); 168} 169 170//===----------------------------------------------------------------------===// 171// Useful predicates. 172//===----------------------------------------------------------------------===// 173 174bool SVal::isConstant() const { 175 return getAs<nonloc::ConcreteInt>() || getAs<loc::ConcreteInt>(); 176} 177 178bool SVal::isConstant(int I) const { 179 if (Optional<loc::ConcreteInt> LV = getAs<loc::ConcreteInt>()) 180 return LV->getValue() == I; 181 if (Optional<nonloc::ConcreteInt> NV = getAs<nonloc::ConcreteInt>()) 182 return NV->getValue() == I; 183 return false; 184} 185 186bool SVal::isZeroConstant() const { 187 return isConstant(0); 188} 189 190 191//===----------------------------------------------------------------------===// 192// Transfer function dispatch for Non-Locs. 193//===----------------------------------------------------------------------===// 194 195SVal nonloc::ConcreteInt::evalBinOp(SValBuilder &svalBuilder, 196 BinaryOperator::Opcode Op, 197 const nonloc::ConcreteInt& R) const { 198 const llvm::APSInt* X = 199 svalBuilder.getBasicValueFactory().evalAPSInt(Op, getValue(), R.getValue()); 200 201 if (X) 202 return nonloc::ConcreteInt(*X); 203 else 204 return UndefinedVal(); 205} 206 207nonloc::ConcreteInt 208nonloc::ConcreteInt::evalComplement(SValBuilder &svalBuilder) const { 209 return svalBuilder.makeIntVal(~getValue()); 210} 211 212nonloc::ConcreteInt 213nonloc::ConcreteInt::evalMinus(SValBuilder &svalBuilder) const { 214 return svalBuilder.makeIntVal(-getValue()); 215} 216 217//===----------------------------------------------------------------------===// 218// Transfer function dispatch for Locs. 219//===----------------------------------------------------------------------===// 220 221SVal loc::ConcreteInt::evalBinOp(BasicValueFactory& BasicVals, 222 BinaryOperator::Opcode Op, 223 const loc::ConcreteInt& R) const { 224 225 assert(BinaryOperator::isComparisonOp(Op) || Op == BO_Sub); 226 227 const llvm::APSInt *X = BasicVals.evalAPSInt(Op, getValue(), R.getValue()); 228 229 if (X) 230 return nonloc::ConcreteInt(*X); 231 else 232 return UndefinedVal(); 233} 234 235//===----------------------------------------------------------------------===// 236// Pretty-Printing. 237//===----------------------------------------------------------------------===// 238 239void SVal::dump() const { dumpToStream(llvm::errs()); } 240 241void SVal::dumpToStream(raw_ostream &os) const { 242 switch (getBaseKind()) { 243 case UnknownKind: 244 os << "Unknown"; 245 break; 246 case NonLocKind: 247 castAs<NonLoc>().dumpToStream(os); 248 break; 249 case LocKind: 250 castAs<Loc>().dumpToStream(os); 251 break; 252 case UndefinedKind: 253 os << "Undefined"; 254 break; 255 } 256} 257 258void NonLoc::dumpToStream(raw_ostream &os) const { 259 switch (getSubKind()) { 260 case nonloc::ConcreteIntKind: { 261 const nonloc::ConcreteInt& C = castAs<nonloc::ConcreteInt>(); 262 if (C.getValue().isUnsigned()) 263 os << C.getValue().getZExtValue(); 264 else 265 os << C.getValue().getSExtValue(); 266 os << ' ' << (C.getValue().isUnsigned() ? 'U' : 'S') 267 << C.getValue().getBitWidth() << 'b'; 268 break; 269 } 270 case nonloc::SymbolValKind: { 271 os << castAs<nonloc::SymbolVal>().getSymbol(); 272 break; 273 } 274 case nonloc::LocAsIntegerKind: { 275 const nonloc::LocAsInteger& C = castAs<nonloc::LocAsInteger>(); 276 os << C.getLoc() << " [as " << C.getNumBits() << " bit integer]"; 277 break; 278 } 279 case nonloc::CompoundValKind: { 280 const nonloc::CompoundVal& C = castAs<nonloc::CompoundVal>(); 281 os << "compoundVal{"; 282 bool first = true; 283 for (nonloc::CompoundVal::iterator I=C.begin(), E=C.end(); I!=E; ++I) { 284 if (first) { 285 os << ' '; first = false; 286 } 287 else 288 os << ", "; 289 290 (*I).dumpToStream(os); 291 } 292 os << "}"; 293 break; 294 } 295 case nonloc::LazyCompoundValKind: { 296 const nonloc::LazyCompoundVal &C = castAs<nonloc::LazyCompoundVal>(); 297 os << "lazyCompoundVal{" << const_cast<void *>(C.getStore()) 298 << ',' << C.getRegion() 299 << '}'; 300 break; 301 } 302 default: 303 assert (false && "Pretty-printed not implemented for this NonLoc."); 304 break; 305 } 306} 307 308void Loc::dumpToStream(raw_ostream &os) const { 309 switch (getSubKind()) { 310 case loc::ConcreteIntKind: 311 os << castAs<loc::ConcreteInt>().getValue().getZExtValue() << " (Loc)"; 312 break; 313 case loc::GotoLabelKind: 314 os << "&&" << castAs<loc::GotoLabel>().getLabel()->getName(); 315 break; 316 case loc::MemRegionKind: 317 os << '&' << castAs<loc::MemRegionVal>().getRegion()->getString(); 318 break; 319 default: 320 llvm_unreachable("Pretty-printing not implemented for this Loc."); 321 } 322} 323