//===-- SVals.cpp - Abstract RValues for Path-Sens. Value Tracking --------===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

//  This file defines SVal, Loc, and NonLoc, classes that represent

//  abstract r-values for use with path-sensitive value tracking.

//

//===----------------------------------------------------------------------===//

#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"

#include "clang/AST/Decl.h"

#include "clang/AST/DeclCXX.h"

#include "clang/AST/Expr.h"

#include "clang/AST/Type.h"

#include "clang/Basic/JsonSupport.h"

#include "clang/Basic/LLVM.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/SymExpr.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"

#include "llvm/ADT/Optional.h"

#include "llvm/Support/Casting.h"

#include "llvm/Support/Compiler.h"

#include "llvm/Support/ErrorHandling.h"

#include "llvm/Support/raw_ostream.h"

#include <cassert>

using namespace clang;

using namespace ento;

//===----------------------------------------------------------------------===//

// Symbol iteration within an SVal.

//===----------------------------------------------------------------------===//

//===----------------------------------------------------------------------===//

// Utility methods.

//===----------------------------------------------------------------------===//

bool SVal::hasConjuredSymbol() const {

  if (Optional<nonloc::SymbolVal> SV = getAs<nonloc::SymbolVal>()) {

    SymbolRef sym = SV->getSymbol();

    if (isa<SymbolConjured>(sym))

      return true;

  }

  if (Optional<loc::MemRegionVal> RV = getAs<loc::MemRegionVal>()) {

    const MemRegion *R = RV->getRegion();

    if (const auto *SR = dyn_cast<SymbolicRegion>(R)) {

      SymbolRef sym = SR->getSymbol();

      if (isa<SymbolConjured>(sym))

        return true;

    }

  }

  return false;

}

const FunctionDecl *SVal::getAsFunctionDecl() const {

  if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) {

    const MemRegion* R = X->getRegion();

    if (const FunctionCodeRegion *CTR = R->getAs<FunctionCodeRegion>())

      if (const auto *FD = dyn_cast<FunctionDecl>(CTR->getDecl()))

        return FD;

  }

  if (auto X = getAs<nonloc::PointerToMember>()) {

    if (const auto *MD = dyn_cast_or_null<CXXMethodDecl>(X->getDecl()))

      return MD;

  }

  return nullptr;

}

/// If this SVal is a location (subclasses Loc) and wraps a symbol,

/// return that SymbolRef.  Otherwise return 0.

///

/// Implicit casts (ex: void* -> char*) can turn Symbolic region into Element

/// region. If that is the case, gets the underlining region.

/// When IncludeBaseRegions is set to true and the SubRegion is non-symbolic,

/// the first symbolic parent region is returned.

SymbolRef SVal::getAsLocSymbol(bool IncludeBaseRegions) const {

  // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?

  if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>())

    return X->getLoc().getAsLocSymbol(IncludeBaseRegions);

  if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) {

    const MemRegion *R = X->getRegion();

    if (const SymbolicRegion *SymR = IncludeBaseRegions ?

                                      R->getSymbolicBase() :

                                      dyn_cast<SymbolicRegion>(R->StripCasts()))

      return SymR->getSymbol();

  }

  return nullptr;

}

/// Get the symbol in the SVal or its base region.

SymbolRef SVal::getLocSymbolInBase() const {

  Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>();

  if (!X)

    return nullptr;

  const MemRegion *R = X->getRegion();

  while (const auto *SR = dyn_cast<SubRegion>(R)) {

    if (const auto *SymR = dyn_cast<SymbolicRegion>(SR))

      return SymR->getSymbol();

    else

      R = SR->getSuperRegion();

  }

  return nullptr;

}

/// If this SVal wraps a symbol return that SymbolRef.

/// Otherwise, return 0.

///

/// Casts are ignored during lookup.

/// \param IncludeBaseRegions The boolean that controls whether the search

/// should continue to the base regions if the region is not symbolic.

SymbolRef SVal::getAsSymbol(bool IncludeBaseRegions) const {

  // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?

  if (Optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>())

    return X->getSymbol();

  return getAsLocSymbol(IncludeBaseRegions);

}

const MemRegion *SVal::getAsRegion() const {

  if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>())

    return X->getRegion();

  if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>())

    return X->getLoc().getAsRegion();

  return nullptr;

}

const MemRegion *loc::MemRegionVal::stripCasts(bool StripBaseCasts) const {

  const MemRegion *R = getRegion();

  return R ?  R->StripCasts(StripBaseCasts) : 
nullptr0
;

}

const void *nonloc::LazyCompoundVal::getStore() const {

  return static_cast<const LazyCompoundValData*>(Data)->getStore();

}

const TypedValueRegion *nonloc::LazyCompoundVal::getRegion() const {

  return static_cast<const LazyCompoundValData*>(Data)->getRegion();

}

bool nonloc::PointerToMember::isNullMemberPointer() const {

  return getPTMData().isNull();

}

const NamedDecl *nonloc::PointerToMember::getDecl() const {

  const auto PTMD = this->getPTMData();

  if (PTMD.isNull())

    return nullptr;

  const NamedDecl *ND = nullptr;

  if (PTMD.is<const NamedDecl *>())

    ND = PTMD.get<const NamedDecl *>();

  else

    ND = PTMD.get<const PointerToMemberData *>()->getDeclaratorDecl();

  return ND;

}

//===----------------------------------------------------------------------===//

// Other Iterators.

//===----------------------------------------------------------------------===//

nonloc::CompoundVal::iterator nonloc::CompoundVal::begin() const {

  return getValue()->begin();

}

nonloc::CompoundVal::iterator nonloc::CompoundVal::end() const {

  return getValue()->end();

}

nonloc::PointerToMember::iterator nonloc::PointerToMember::begin() const {

  const PTMDataType PTMD = getPTMData();

  if (PTMD.is<const NamedDecl *>())

    return {};

  return PTMD.get<const PointerToMemberData *>()->begin();

}

nonloc::PointerToMember::iterator nonloc::PointerToMember::end() const {

  const PTMDataType PTMD = getPTMData();

  if (PTMD.is<const NamedDecl *>())

    return {};

  return PTMD.get<const PointerToMemberData *>()->end();

}

//===----------------------------------------------------------------------===//

// Useful predicates.

//===----------------------------------------------------------------------===//

bool SVal::isConstant() const {

  return getAs<nonloc::ConcreteInt>() || 
getAs<loc::ConcreteInt>()694k
;

}

bool SVal::isConstant(int I) const {

  if (Optional<loc::ConcreteInt> LV = getAs<loc::ConcreteInt>())

    return LV->getValue() == I;

  if (Optional<nonloc::ConcreteInt> NV = getAs<nonloc::ConcreteInt>())

    return NV->getValue() == I;

  return false;

}

bool SVal::isZeroConstant() const {

  return isConstant(0);

}

//===----------------------------------------------------------------------===//

// Transfer function dispatch for Non-Locs.

//===----------------------------------------------------------------------===//

SVal nonloc::ConcreteInt::evalBinOp(SValBuilder &svalBuilder,

                                    BinaryOperator::Opcode Op,

                                    const nonloc::ConcreteInt& R) const {

  const llvm::APSInt* X =

    svalBuilder.getBasicValueFactory().evalAPSInt(Op, getValue(), R.getValue());

  if (X)

    return nonloc::ConcreteInt(*X);

  else

    return UndefinedVal();

}

nonloc::ConcreteInt

nonloc::ConcreteInt::evalComplement(SValBuilder &svalBuilder) const {

  return svalBuilder.makeIntVal(~getValue());

}

nonloc::ConcreteInt

nonloc::ConcreteInt::evalMinus(SValBuilder &svalBuilder) const {

  return svalBuilder.makeIntVal(-getValue());

}

//===----------------------------------------------------------------------===//

// Transfer function dispatch for Locs.

//===----------------------------------------------------------------------===//

SVal loc::ConcreteInt::evalBinOp(BasicValueFactory& BasicVals,

                                 BinaryOperator::Opcode Op,

                                 const loc::ConcreteInt& R) const {

  assert(BinaryOperator::isComparisonOp(Op) || Op == BO_Sub);

  const llvm::APSInt *X = BasicVals.evalAPSInt(Op, getValue(), R.getValue());

  if (X)

    return nonloc::ConcreteInt(*X);

  else

    return UndefinedVal();

}

//===----------------------------------------------------------------------===//

// Pretty-Printing.

//===----------------------------------------------------------------------===//

LLVM_DUMP_METHOD void SVal::dump() const { dumpToStream(llvm::errs()); }

void SVal::printJson(raw_ostream &Out, bool AddQuotes) const {

  std::string Buf;

  llvm::raw_string_ostream TempOut(Buf);

  dumpToStream(TempOut);

  Out << JsonFormat(TempOut.str(), AddQuotes);

}

void SVal::dumpToStream(raw_ostream &os) const {

  switch (getBaseKind()) {

    case UnknownValKind:

      os << "Unknown";

      break;

    case NonLocKind:

      castAs<NonLoc>().dumpToStream(os);

      break;

    case LocKind:

      castAs<Loc>().dumpToStream(os);

      break;

    case UndefinedValKind:

      os << "Undefined";

      break;

  }

}

void NonLoc::dumpToStream(raw_ostream &os) const {

  switch (getSubKind()) {

    case nonloc::ConcreteIntKind: {

      const auto &Value = castAs<nonloc::ConcreteInt>().getValue();

      os << Value << ' ' << (Value.isSigned() ? 'S' : 
'U'1
)

         << Value.getBitWidth() << 'b';

      break;

    }

    case nonloc::SymbolValKind:

      os << castAs<nonloc::SymbolVal>().getSymbol();

      break;

    case nonloc::LocAsIntegerKind: {

      const nonloc::LocAsInteger& C = castAs<nonloc::LocAsInteger>();

      os << C.getLoc() << " [as " << C.getNumBits() << " bit integer]";

      break;

    }

    case nonloc::CompoundValKind: {

      const nonloc::CompoundVal& C = castAs<nonloc::CompoundVal>();

      os << "compoundVal{";

      bool first = true;

      for (const auto &I : C) {

        if (first) {

          os << ' '; first = false;

        }

        else

          os << ", ";

        I.dumpToStream(os);

      }

      os << "}";

      break;

    }

    case nonloc::LazyCompoundValKind: {

      const nonloc::LazyCompoundVal &C = castAs<nonloc::LazyCompoundVal>();

      os << "lazyCompoundVal{" << const_cast<void *>(C.getStore())

         << ',' << C.getRegion()

         << '}';

      break;

    }

    case nonloc::PointerToMemberKind: {

      os << "pointerToMember{";

      const nonloc::PointerToMember &CastRes =

          castAs<nonloc::PointerToMember>();

      if (CastRes.getDecl())

        os << "|" << CastRes.getDecl()->getQualifiedNameAsString() << "|";

      bool first = true;

      for (const auto &I : CastRes) {

        if (first) {

          os << ' '; first = false;

        }

        else

          os << ", ";

        os << (*I).getType().getAsString();

      }

      os << '}';

      break;

    }

    default:

      assert(false && "Pretty-printed not implemented for this NonLoc.");

      break;

  }

}

void Loc::dumpToStream(raw_ostream &os) const {

  switch (getSubKind()) {

    case loc::ConcreteIntKind:

      os << castAs<loc::ConcreteInt>().getValue().getZExtValue() << " (Loc)";

      break;

    case loc::GotoLabelKind:

      os << "&&" << castAs<loc::GotoLabel>().getLabel()->getName();

      break;

    case loc::MemRegionValKind:

      os << '&' << castAs<loc::MemRegionVal>().getRegion()->getString();

      break;

    default:

      llvm_unreachable("Pretty-printing not implemented for this Loc.");

  }

}