394 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8//9// This file defines SVal, Loc, and NonLoc, classes that represent10// 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/ASTContext.h"16#include "clang/AST/Decl.h"17#include "clang/AST/DeclCXX.h"18#include "clang/AST/Expr.h"19#include "clang/AST/Type.h"20#include "clang/Basic/JsonSupport.h"21#include "clang/Basic/LLVM.h"22#include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h"23#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"24#include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"25#include "clang/StaticAnalyzer/Core/PathSensitive/SValVisitor.h"26#include "clang/StaticAnalyzer/Core/PathSensitive/SymExpr.h"27#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"28#include "llvm/Support/Compiler.h"29#include "llvm/Support/ErrorHandling.h"30#include "llvm/Support/raw_ostream.h"31#include <cassert>32#include <optional>33 34using namespace clang;35using namespace ento;36 37//===----------------------------------------------------------------------===//38// Symbol iteration within an SVal.39//===----------------------------------------------------------------------===//40 41//===----------------------------------------------------------------------===//42// Utility methods.43//===----------------------------------------------------------------------===//44 45const FunctionDecl *SVal::getAsFunctionDecl() const {46 if (std::optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) {47 const MemRegion* R = X->getRegion();48 if (const FunctionCodeRegion *CTR = R->getAs<FunctionCodeRegion>())49 if (const auto *FD = dyn_cast<FunctionDecl>(CTR->getDecl()))50 return FD;51 }52 53 if (auto X = getAs<nonloc::PointerToMember>()) {54 if (const auto *MD = dyn_cast_or_null<CXXMethodDecl>(X->getDecl()))55 return MD;56 }57 return nullptr;58}59 60/// If this SVal is a location (subclasses Loc) and wraps a symbol,61/// return that SymbolRef. Otherwise return 0.62///63/// Implicit casts (ex: void* -> char*) can turn Symbolic region into Element64/// region. If that is the case, gets the underlining region.65/// When IncludeBaseRegions is set to true and the SubRegion is non-symbolic,66/// the first symbolic parent region is returned.67SymbolRef SVal::getAsLocSymbol(bool IncludeBaseRegions) const {68 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?69 if (const MemRegion *R = getAsRegion())70 if (const SymbolicRegion *SymR =71 IncludeBaseRegions ? R->getSymbolicBase()72 : dyn_cast<SymbolicRegion>(R->StripCasts()))73 return SymR->getSymbol();74 75 return nullptr;76}77 78/// Get the symbol in the SVal or its base region.79SymbolRef SVal::getLocSymbolInBase() const {80 std::optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>();81 82 if (!X)83 return nullptr;84 85 const MemRegion *R = X->getRegion();86 87 while (const auto *SR = dyn_cast<SubRegion>(R)) {88 if (const auto *SymR = dyn_cast<SymbolicRegion>(SR))89 return SymR->getSymbol();90 else91 R = SR->getSuperRegion();92 }93 94 return nullptr;95}96 97/// If this SVal wraps a symbol return that SymbolRef.98/// Otherwise, return 0.99///100/// Casts are ignored during lookup.101/// \param IncludeBaseRegions The boolean that controls whether the search102/// should continue to the base regions if the region is not symbolic.103SymbolRef SVal::getAsSymbol(bool IncludeBaseRegions) const {104 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?105 if (std::optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>())106 return X->getSymbol();107 108 return getAsLocSymbol(IncludeBaseRegions);109}110 111const llvm::APSInt *SVal::getAsInteger() const {112 if (auto CI = getAs<nonloc::ConcreteInt>())113 return CI->getValue().get();114 if (auto CI = getAs<loc::ConcreteInt>())115 return CI->getValue().get();116 return nullptr;117}118 119const MemRegion *SVal::getAsRegion() const {120 if (std::optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>())121 return X->getRegion();122 123 if (std::optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>())124 return X->getLoc().getAsRegion();125 126 return nullptr;127}128 129namespace {130class TypeRetrievingVisitor131 : public FullSValVisitor<TypeRetrievingVisitor, QualType> {132private:133 const ASTContext &Context;134 135public:136 TypeRetrievingVisitor(const ASTContext &Context) : Context(Context) {}137 138 QualType VisitMemRegionVal(loc::MemRegionVal MRV) {139 return Visit(MRV.getRegion());140 }141 QualType VisitGotoLabel(loc::GotoLabel GL) {142 return QualType{Context.VoidPtrTy};143 }144 template <class ConcreteInt> QualType VisitConcreteInt(ConcreteInt CI) {145 const llvm::APSInt &Value = CI.getValue();146 if (1 == Value.getBitWidth())147 return Context.BoolTy;148 return Context.getIntTypeForBitwidth(Value.getBitWidth(), Value.isSigned());149 }150 QualType VisitLocAsInteger(nonloc::LocAsInteger LI) {151 QualType NestedType = Visit(LI.getLoc());152 if (NestedType.isNull())153 return NestedType;154 155 return Context.getIntTypeForBitwidth(LI.getNumBits(),156 NestedType->isSignedIntegerType());157 }158 QualType VisitCompoundVal(nonloc::CompoundVal CV) {159 return CV.getValue()->getType();160 }161 QualType VisitLazyCompoundVal(nonloc::LazyCompoundVal LCV) {162 return LCV.getRegion()->getValueType();163 }164 QualType VisitSymbolVal(nonloc::SymbolVal SV) {165 return Visit(SV.getSymbol());166 }167 QualType VisitSymbolicRegion(const SymbolicRegion *SR) {168 return Visit(SR->getSymbol());169 }170 QualType VisitAllocaRegion(const AllocaRegion *) {171 return QualType{Context.VoidPtrTy};172 }173 QualType VisitTypedRegion(const TypedRegion *TR) {174 return TR->getLocationType();175 }176 QualType VisitSymExpr(const SymExpr *SE) { return SE->getType(); }177};178} // end anonymous namespace179 180QualType SVal::getType(const ASTContext &Context) const {181 TypeRetrievingVisitor TRV{Context};182 return TRV.Visit(*this);183}184 185const MemRegion *loc::MemRegionVal::stripCasts(bool StripBaseCasts) const {186 return getRegion()->StripCasts(StripBaseCasts);187}188 189const void *nonloc::LazyCompoundVal::getStore() const {190 return static_cast<const LazyCompoundValData*>(Data)->getStore();191}192 193const TypedValueRegion *nonloc::LazyCompoundVal::getRegion() const {194 return static_cast<const LazyCompoundValData*>(Data)->getRegion();195}196 197bool nonloc::PointerToMember::isNullMemberPointer() const {198 return getPTMData().isNull();199}200 201const NamedDecl *nonloc::PointerToMember::getDecl() const {202 const auto PTMD = this->getPTMData();203 if (PTMD.isNull())204 return nullptr;205 206 const NamedDecl *ND = nullptr;207 if (const auto *NDP = dyn_cast<const NamedDecl *>(PTMD))208 ND = NDP;209 else210 ND = cast<const PointerToMemberData *>(PTMD)->getDeclaratorDecl();211 212 return ND;213}214 215//===----------------------------------------------------------------------===//216// Other Iterators.217//===----------------------------------------------------------------------===//218 219nonloc::CompoundVal::iterator nonloc::CompoundVal::begin() const {220 return getValue()->begin();221}222 223nonloc::CompoundVal::iterator nonloc::CompoundVal::end() const {224 return getValue()->end();225}226 227nonloc::PointerToMember::iterator nonloc::PointerToMember::begin() const {228 const PTMDataType PTMD = getPTMData();229 if (isa<const NamedDecl *>(PTMD))230 return {};231 return cast<const PointerToMemberData *>(PTMD)->begin();232}233 234nonloc::PointerToMember::iterator nonloc::PointerToMember::end() const {235 const PTMDataType PTMD = getPTMData();236 if (isa<const NamedDecl *>(PTMD))237 return {};238 return cast<const PointerToMemberData *>(PTMD)->end();239}240 241//===----------------------------------------------------------------------===//242// Useful predicates.243//===----------------------------------------------------------------------===//244 245bool SVal::isConstant() const {246 return getAs<nonloc::ConcreteInt>() || getAs<loc::ConcreteInt>();247}248 249bool SVal::isConstant(int I) const {250 if (std::optional<loc::ConcreteInt> LV = getAs<loc::ConcreteInt>())251 return *LV->getValue() == I;252 if (std::optional<nonloc::ConcreteInt> NV = getAs<nonloc::ConcreteInt>())253 return *NV->getValue() == I;254 return false;255}256 257bool SVal::isZeroConstant() const {258 return isConstant(0);259}260 261//===----------------------------------------------------------------------===//262// Pretty-Printing.263//===----------------------------------------------------------------------===//264 265StringRef SVal::getKindStr() const {266 switch (getKind()) {267#define BASIC_SVAL(Id, Parent) \268 case Id##Kind: \269 return #Id;270#define LOC_SVAL(Id, Parent) \271 case Loc##Id##Kind: \272 return #Id;273#define NONLOC_SVAL(Id, Parent) \274 case NonLoc##Id##Kind: \275 return #Id;276#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.def"277#undef REGION278 }279 llvm_unreachable("Unkown kind!");280}281 282LLVM_DUMP_METHOD void SVal::dump() const { dumpToStream(llvm::errs()); }283 284void SVal::printJson(raw_ostream &Out, bool AddQuotes) const {285 std::string Buf;286 llvm::raw_string_ostream TempOut(Buf);287 288 dumpToStream(TempOut);289 290 Out << JsonFormat(Buf, AddQuotes);291}292 293void SVal::dumpToStream(raw_ostream &os) const {294 if (isUndef()) {295 os << "Undefined";296 return;297 }298 if (isUnknown()) {299 os << "Unknown";300 return;301 }302 if (NonLoc::classof(*this)) {303 castAs<NonLoc>().dumpToStream(os);304 return;305 }306 if (Loc::classof(*this)) {307 castAs<Loc>().dumpToStream(os);308 return;309 }310 llvm_unreachable("Unhandled SVal kind!");311}312 313void NonLoc::dumpToStream(raw_ostream &os) const {314 switch (getKind()) {315 case nonloc::ConcreteIntKind: {316 APSIntPtr 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 else339 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 else365 os << ", ";366 367 os << I->getType();368 }369 370 os << '}';371 break;372 }373 default:374 assert(false && "Pretty-printed not implemented for this NonLoc.");375 break;376 }377}378 379void Loc::dumpToStream(raw_ostream &os) const {380 switch (getKind()) {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