C++ QualType::isPointerType方法代码示例

static bool pointedUnqualifiedTypesAreEqual(QualType T1, QualType T2) {
  while ((T1->isPointerType() && T2->isPointerType()) ||
         (T1->isReferenceType() && T2->isReferenceType())) {
    T1 = T1->getPointeeType();
    T2 = T2->getPointeeType();
  }
  return T1.getUnqualifiedType() == T2.getUnqualifiedType();
}

bool pointedTypesAreEqual(QualType SourceType, QualType DestType) {
  SourceType = SourceType.getNonReferenceType();
  DestType = DestType.getNonReferenceType();
  while (SourceType->isPointerType() && DestType->isPointerType()) {
    SourceType = SourceType->getPointeeType();
    DestType = DestType->getPointeeType();
  }
  return SourceType.getUnqualifiedType() == DestType.getUnqualifiedType();
}

bool needsConstCast(QualType SourceType, QualType DestType) {
  SourceType = SourceType.getNonReferenceType();
  DestType = DestType.getNonReferenceType();
  while (SourceType->isPointerType() && DestType->isPointerType()) {
    SourceType = SourceType->getPointeeType();
    DestType = DestType->getPointeeType();
    if (SourceType.isConstQualified() && !DestType.isConstQualified())
      return true;
  }
  return false;
}

static bool needsConstCast(QualType SourceType, QualType DestType) {
  while ((SourceType->isPointerType() && DestType->isPointerType()) ||
         (SourceType->isReferenceType() && DestType->isReferenceType())) {
    SourceType = SourceType->getPointeeType();
    DestType = DestType->getPointeeType();
    if (SourceType.isConstQualified() && !DestType.isConstQualified()) {
      return (SourceType->isPointerType() == DestType->isPointerType()) &&
             (SourceType->isReferenceType() == DestType->isReferenceType());
    }
  }
  return false;
}

void FixedAddressChecker::checkPreStmt(const BinaryOperator *B,
                                       CheckerContext &C) const {
  // Using a fixed address is not portable because that address will probably
  // not be valid in all environments or platforms.

  if (B->getOpcode() != BO_Assign)
    return;

  QualType T = B->getType();
  if (!T->isPointerType())
    return;

  SVal RV = C.getSVal(B->getRHS());

  if (!RV.isConstant() || RV.isZeroConstant())
    return;

  if (ExplodedNode *N = C.generateNonFatalErrorNode()) {
    if (!BT)
      BT.reset(
          new BuiltinBug(this, "Use fixed address",
                         "Using a fixed address is not portable because that "
                         "address will probably not be valid in all "
                         "environments or platforms."));
    auto R = llvm::make_unique<BugReport>(*BT, BT->getDescription(), N);
    R->addRange(B->getRHS()->getSourceRange());
    C.emitReport(std::move(R));
  }
}

void FixedAddressChecker::checkPreStmt(const BinaryOperator *B,
                                       CheckerContext &C) const {
  // Using a fixed address is not portable because that address will probably
  // not be valid in all environments or platforms.

  if (B->getOpcode() != BO_Assign)
    return;

  QualType T = B->getType();
  if (!T->isPointerType())
    return;

  ProgramStateRef state = C.getState();
  SVal RV = state->getSVal(B->getRHS(), C.getLocationContext());

  if (!RV.isConstant() || RV.isZeroConstant())
    return;

  if (ExplodedNode *N = C.addTransition()) {
    if (!BT)
      BT.reset(
          new BuiltinBug(this, "Use fixed address",
                         "Using a fixed address is not portable because that "
                         "address will probably not be valid in all "
                         "environments or platforms."));
    BugReport *R = new BugReport(*BT, BT->getDescription(), N);
    R->addRange(B->getRHS()->getSourceRange());
    C.emitReport(R);
  }
}

  ValuePrinterInfo::ValuePrinterInfo(Expr* E, ASTContext* Ctx)
    : m_Expr(E), m_Context(Ctx), m_Flags(0) {
    assert(E && "Expression cannot be null!");
    assert(Ctx && "ASTContext cannot be null!");
    // 1. Get the flags
    const QualType QT = m_Expr->getType();

    if (E->isRValue() || QT.isLocalConstQualified() || QT.isConstant(*Ctx)){
      m_Flags |= VPI_Const;
    }

    if (QT->isPointerType()) {
      // treat arrary-to-pointer decay as array:
      QualType PQT = QT->getPointeeType();
      const Type* PTT = PQT.getTypePtr();
      if (!PTT || !PTT->isArrayType()) {
        m_Flags |= VPI_Ptr;
        if (const RecordType* RT = dyn_cast<RecordType>(QT.getTypePtr()))
          if (RecordDecl* RD = RT->getDecl()) {
            CXXRecordDecl* CRD = dyn_cast<CXXRecordDecl>(RD);
            if (CRD && CRD->isPolymorphic())
              m_Flags |= VPI_Polymorphic;
          }
      }
    }
  }

/// CastRetrievedVal - Used by subclasses of StoreManager to implement
///  implicit casts that arise from loads from regions that are reinterpreted
///  as another region.
SVal StoreManager::CastRetrievedVal(SVal V, const TypedValueRegion *R,
                                    QualType castTy) {
  if (castTy.isNull() || V.isUnknownOrUndef())
    return V;

  // The dispatchCast() call below would convert the int into a float.
  // What we want, however, is a bit-by-bit reinterpretation of the int
  // as a float, which usually yields nothing garbage. For now skip casts
  // from ints to floats.
  // TODO: What other combinations of types are affected?
  if (castTy->isFloatingType()) {
    SymbolRef Sym = V.getAsSymbol();
    if (Sym && !Sym->getType()->isFloatingType())
      return UnknownVal();
  }

  // When retrieving symbolic pointer and expecting a non-void pointer,
  // wrap them into element regions of the expected type if necessary.
  // SValBuilder::dispatchCast() doesn't do that, but it is necessary to
  // make sure that the retrieved value makes sense, because there's no other
  // cast in the AST that would tell us to cast it to the correct pointer type.
  // We might need to do that for non-void pointers as well.
  // FIXME: We really need a single good function to perform casts for us
  // correctly every time we need it.
  if (castTy->isPointerType() && !castTy->isVoidPointerType())
    if (const auto *SR = dyn_cast_or_null<SymbolicRegion>(V.getAsRegion()))
      if (SR->getSymbol()->getType().getCanonicalType() !=
          castTy.getCanonicalType())
        return loc::MemRegionVal(castRegion(SR, castTy));

  return svalBuilder.dispatchCast(V, castTy);
}

void FixedAddressChecker::PreVisitBinaryOperator(CheckerContext &C,
                                                 const BinaryOperator *B) {
  // Using a fixed address is not portable because that address will probably
  // not be valid in all environments or platforms.

  if (B->getOpcode() != BinaryOperator::Assign)
    return;

  QualType T = B->getType();
  if (!T->isPointerType())
    return;

  const GRState *state = C.getState();

  SVal RV = state->getSVal(B->getRHS());

  if (!RV.isConstant() || RV.isZeroConstant())
    return;

  if (ExplodedNode *N = C.GenerateNode()) {
    if (!BT)
      BT = new BuiltinBug("Use fixed address", 
                          "Using a fixed address is not portable because that "
                          "address will probably not be valid in all "
                          "environments or platforms.");
    RangedBugReport *R = new RangedBugReport(*BT, BT->getDescription(), N);
    R->addRange(B->getRHS()->getSourceRange());
    C.EmitReport(R);
  }
}

/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
/// If there is already an implicit cast, merge into the existing one.
/// If isLvalue, the result of the cast is an lvalue.
void Sema::ImpCastExprToType(Expr *&Expr, QualType Ty,
                             CastExpr::CastKind Kind, bool isLvalue) {
  QualType ExprTy = Context.getCanonicalType(Expr->getType());
  QualType TypeTy = Context.getCanonicalType(Ty);

  if (ExprTy == TypeTy)
    return;

  if (Expr->getType()->isPointerType() && Ty->isPointerType()) {
    QualType ExprBaseType = cast<PointerType>(ExprTy)->getPointeeType();
    QualType BaseType = cast<PointerType>(TypeTy)->getPointeeType();
    if (ExprBaseType.getAddressSpace() != BaseType.getAddressSpace()) {
      Diag(Expr->getExprLoc(), diag::err_implicit_pointer_address_space_cast)
        << Expr->getSourceRange();
    }
  }

  CheckImplicitConversion(Expr, Ty);

  if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(Expr)) {
    if (ImpCast->getCastKind() == Kind) {
      ImpCast->setType(Ty);
      ImpCast->setLvalueCast(isLvalue);
      return;
    }
  }

  Expr = new (Context) ImplicitCastExpr(Ty, Kind, Expr, isLvalue);
}

// CWE-467: Use of sizeof() on a Pointer Type
void WalkAST::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E) {
    if (E->getKind() != UETT_SizeOf)
        return;

    // If an explicit type is used in the code, usually the coder knows what he is
    // doing.
    if (E->isArgumentType())
        return;

    QualType T = E->getTypeOfArgument();
    if (T->isPointerType()) {

        // Many false positives have the form 'sizeof *p'. This is reasonable
        // because people know what they are doing when they intentionally
        // dereference the pointer.
        Expr *ArgEx = E->getArgumentExpr();
        if (!isa<DeclRefExpr>(ArgEx->IgnoreParens()))
            return;

        PathDiagnosticLocation ELoc =
            PathDiagnosticLocation::createBegin(E, BR.getSourceManager(), AC);
        BR.EmitBasicReport(AC->getDecl(), Checker,
                           "Potential unintended use of sizeof() on pointer type",
                           categories::LogicError,
                           "The code calls sizeof() on a pointer type. "
                           "This can produce an unexpected result.",
                           ELoc, ArgEx->getSourceRange());
    }
}

void NonConstParameterCheck::check(const MatchFinder::MatchResult &Result) {
  if (const auto *Parm = Result.Nodes.getNodeAs<ParmVarDecl>("Parm")) {
    if (const DeclContext *D = Parm->getParentFunctionOrMethod()) {
      if (const auto *M = dyn_cast<CXXMethodDecl>(D)) {
        if (M->isVirtual() || M->size_overridden_methods() != 0)
          return;
      }
    }
    addParm(Parm);
  } else if (const auto *Ctor =
                 Result.Nodes.getNodeAs<CXXConstructorDecl>("Ctor")) {
    for (const auto *Parm : Ctor->parameters())
      addParm(Parm);
    for (const auto *Init : Ctor->inits())
      markCanNotBeConst(Init->getInit(), true);
  } else if (const auto *Ref = Result.Nodes.getNodeAs<DeclRefExpr>("Ref")) {
    setReferenced(Ref);
  } else if (const auto *S = Result.Nodes.getNodeAs<Stmt>("Mark")) {
    if (const auto *B = dyn_cast<BinaryOperator>(S)) {
      if (B->isAssignmentOp())
        markCanNotBeConst(B, false);
    } else if (const auto *CE = dyn_cast<CallExpr>(S)) {
      // Typically, if a parameter is const then it is fine to make the data
      // const. But sometimes the data is written even though the parameter
      // is const. Mark all data passed by address to the function.
      for (const auto *Arg : CE->arguments()) {
        markCanNotBeConst(Arg->IgnoreParenCasts(), true);
      }

      // Data passed by nonconst reference should not be made const.
      if (const FunctionDecl *FD = CE->getDirectCallee()) {
        unsigned ArgNr = 0U;
        for (const auto *Par : FD->parameters()) {
          if (ArgNr >= CE->getNumArgs())
            break;
          const Expr *Arg = CE->getArg(ArgNr++);
          // Is this a non constant reference parameter?
          const Type *ParType = Par->getType().getTypePtr();
          if (!ParType->isReferenceType() || Par->getType().isConstQualified())
            continue;
          markCanNotBeConst(Arg->IgnoreParenCasts(), false);
        }
      }
    } else if (const auto *CE = dyn_cast<CXXConstructExpr>(S)) {
      for (const auto *Arg : CE->arguments()) {
        markCanNotBeConst(Arg->IgnoreParenCasts(), true);
      }
    } else if (const auto *R = dyn_cast<ReturnStmt>(S)) {
      markCanNotBeConst(R->getRetValue(), true);
    } else if (const auto *U = dyn_cast<UnaryOperator>(S)) {
      markCanNotBeConst(U, true);
    }
  } else if (const auto *VD = Result.Nodes.getNodeAs<VarDecl>("Mark")) {
    const QualType T = VD->getType();
    if ((T->isPointerType() && !T->getPointeeType().isConstQualified()) ||
        T->isArrayType())
      markCanNotBeConst(VD->getInit(), true);
  }
}

bool ConditionBRVisitor::patternMatch(const Expr *Ex, raw_ostream &Out,
                                      BugReporterContext &BRC,
                                      BugReport &report,
                                      const ExplodedNode *N,
                                      Optional<bool> &prunable) {
  const Expr *OriginalExpr = Ex;
  Ex = Ex->IgnoreParenCasts();

  if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Ex)) {
    const bool quotes = isa<VarDecl>(DR->getDecl());
    if (quotes) {
      Out << '\'';
      const LocationContext *LCtx = N->getLocationContext();
      const ProgramState *state = N->getState().getPtr();
      if (const MemRegion *R = state->getLValue(cast<VarDecl>(DR->getDecl()),
                                                LCtx).getAsRegion()) {
        if (report.isInteresting(R))
          prunable = false;
        else {
          const ProgramState *state = N->getState().getPtr();
          SVal V = state->getSVal(R);
          if (report.isInteresting(V))
            prunable = false;
        }
      }
    }
    Out << DR->getDecl()->getDeclName().getAsString();
    if (quotes)
      Out << '\'';
    return quotes;
  }
  
  if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(Ex)) {
    QualType OriginalTy = OriginalExpr->getType();
    if (OriginalTy->isPointerType()) {
      if (IL->getValue() == 0) {
        Out << "null";
        return false;
      }
    }
    else if (OriginalTy->isObjCObjectPointerType()) {
      if (IL->getValue() == 0) {
        Out << "nil";
        return false;
      }
    }
    
    Out << IL->getValue();
    return false;
  }
  
  return false;
}

/// CastsAwayConstness - Check if the pointer conversion from SrcType to
/// DestType casts away constness as defined in C++ 5.2.11p8ff. This is used by
/// the cast checkers.  Both arguments must denote pointer (possibly to member)
/// types.
bool
CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType)
{
  // Casting away constness is defined in C++ 5.2.11p8 with reference to
  // C++ 4.4. We piggyback on Sema::IsQualificationConversion for this, since
  // the rules are non-trivial. So first we construct Tcv *...cv* as described
  // in C++ 5.2.11p8.
  assert((SrcType->isPointerType() || SrcType->isMemberPointerType()) &&
         "Source type is not pointer or pointer to member.");
  assert((DestType->isPointerType() || DestType->isMemberPointerType()) &&
         "Destination type is not pointer or pointer to member.");

  QualType UnwrappedSrcType = SrcType, UnwrappedDestType = DestType;
  llvm::SmallVector<unsigned, 8> cv1, cv2;

  // Find the qualifications.
  while (Self.UnwrapSimilarPointerTypes(UnwrappedSrcType, UnwrappedDestType)) {
    cv1.push_back(UnwrappedSrcType.getCVRQualifiers());
    cv2.push_back(UnwrappedDestType.getCVRQualifiers());
  }
  assert(cv1.size() > 0 && "Must have at least one pointer level.");

  // Construct void pointers with those qualifiers (in reverse order of
  // unwrapping, of course).
  QualType SrcConstruct = Self.Context.VoidTy;
  QualType DestConstruct = Self.Context.VoidTy;
  for (llvm::SmallVector<unsigned, 8>::reverse_iterator i1 = cv1.rbegin(),
                                                        i2 = cv2.rbegin();
       i1 != cv1.rend(); ++i1, ++i2)
  {
    SrcConstruct = Self.Context.getPointerType(
      SrcConstruct.getQualifiedType(*i1));
    DestConstruct = Self.Context.getPointerType(
      DestConstruct.getQualifiedType(*i2));
  }

  // Test if they're compatible.
  return SrcConstruct != DestConstruct &&
    !Self.IsQualificationConversion(SrcConstruct, DestConstruct);
}

// Check if type is a "Field() *" pointer type, or alternatively a pointer to
// any type in "alt" if provided.
bool CheckAllocationsInFunctionVisitor::IsFieldPointer(
    const QualType& qtype, const char* alt)
{
    if (qtype->isPointerType())
    {
        auto name = qtype->getPointeeType()
            .getDesugaredType(_mainVisitor->getContext()).getAsString();
        return StartsWith(name, "class Memory::WriteBarrierPtr<")
            || StartsWith(name, "typename WriteBarrierFieldTypeTraits<")
            || (alt && strstr(alt, name.c_str()));
    }

    return false;
}