void StringLiteralWithEmbeddedNulCheck::registerMatchers(MatchFinder *Finder) {
  // Match a string that contains embedded NUL character. Extra-checks are
  // applied in |check| to find incorectly escaped characters.
  Finder->addMatcher(stringLiteral(containsNul()).bind("strlit"), this);

  // The remaining checks only apply to C++.
  if (!getLangOpts().CPlusPlus)
    return;

  const auto StrLitWithNul =
      ignoringParenImpCasts(stringLiteral(containsNul()).bind("truncated"));

  // Match string constructor.
  const auto StringConstructorExpr = expr(anyOf(
      cxxConstructExpr(argumentCountIs(1),
                       hasDeclaration(cxxMethodDecl(hasName("basic_string")))),
      // If present, the second argument is the alloc object which must not
      // be present explicitly.
      cxxConstructExpr(argumentCountIs(2),
                       hasDeclaration(cxxMethodDecl(hasName("basic_string"))),
                       hasArgument(1, cxxDefaultArgExpr()))));

  // Detect passing a suspicious string literal to a string constructor.
  // example: std::string str = "abc\0def";
  Finder->addMatcher(
      cxxConstructExpr(StringConstructorExpr, hasArgument(0, StrLitWithNul)),
      this);

  // Detect passing a suspicious string literal through an overloaded operator.
  Finder->addMatcher(cxxOperatorCallExpr(hasAnyArgument(StrLitWithNul)), this);
}
void InaccurateEraseCheck::registerMatchers(MatchFinder *Finder) {
  // Only register the matchers for C++; the functionality currently does not
  // provide any benefit to other languages, despite being benign.
  if (!getLangOpts().CPlusPlus)
    return;

  const auto EndCall =
      callExpr(
          callee(functionDecl(hasAnyName("remove", "remove_if", "unique"))),
          hasArgument(
              1,
              anyOf(cxxConstructExpr(has(ignoringImplicit(
                        cxxMemberCallExpr(callee(cxxMethodDecl(hasName("end"))))
                            .bind("end")))),
                    anything())))
          .bind("alg");

  const auto DeclInStd = type(hasUnqualifiedDesugaredType(
      tagType(hasDeclaration(decl(isInStdNamespace())))));
  Finder->addMatcher(
      cxxMemberCallExpr(
          on(anyOf(hasType(DeclInStd), hasType(pointsTo(DeclInStd)))),
          callee(cxxMethodDecl(hasName("erase"))), argumentCountIs(1),
          hasArgument(0, has(ignoringImplicit(
                             anyOf(EndCall, has(ignoringImplicit(EndCall)))))),
          unless(isInTemplateInstantiation()))
          .bind("erase"),
      this);
}
void InaccurateEraseCheck::registerMatchers(MatchFinder *Finder) {
  // Only register the matchers for C++; the functionality currently does not
  // provide any benefit to other languages, despite being benign.
  if (!getLangOpts().CPlusPlus)
    return;

  const auto CheckForEndCall = hasArgument(
      1, anyOf(cxxConstructExpr(has(ignoringParenImpCasts(
                   cxxMemberCallExpr(callee(cxxMethodDecl(hasName("end"))))
                       .bind("InaccEndCall")))),
               anything()));

  Finder->addMatcher(
      cxxMemberCallExpr(
          on(hasType(namedDecl(matchesName("^::std::")))),
          callee(cxxMethodDecl(hasName("erase"))), argumentCountIs(1),
          hasArgument(0, has(ignoringParenImpCasts(
                             callExpr(callee(functionDecl(matchesName(
                                          "^::std::(remove(_if)?|unique)$"))),
                                      CheckForEndCall)
                                 .bind("InaccAlgCall")))),
          unless(isInTemplateInstantiation()))
          .bind("InaccErase"),
      this);
}
void PassByValueCheck::registerMatchers(MatchFinder *Finder) {
  // Only register the matchers for C++; the functionality currently does not
  // provide any benefit to other languages, despite being benign.
  if (!getLangOpts().CPlusPlus)
    return;

  Finder->addMatcher(
      cxxConstructorDecl(
          forEachConstructorInitializer(
              cxxCtorInitializer(
                  // Clang builds a CXXConstructExpr only whin it knows which
                  // constructor will be called. In dependent contexts a
                  // ParenListExpr is generated instead of a CXXConstructExpr,
                  // filtering out templates automatically for us.
                  withInitializer(cxxConstructExpr(
                      has(ignoringParenImpCasts(declRefExpr(to(
                          parmVarDecl(
                              hasType(qualType(
                                  // Match only const-ref or a non-const value
                                  // parameters. Rvalues and const-values
                                  // shouldn't be modified.
                                  anyOf(constRefType(), nonConstValueType()))))
                              .bind("Param"))))),
                      hasDeclaration(cxxConstructorDecl(
                          isCopyConstructor(), unless(isDeleted()),
                          hasDeclContext(
                              cxxRecordDecl(isMoveConstructible())))))))
                  .bind("Initializer")))
          .bind("Ctor"),
      this);
}
void IncorrectRoundings::registerMatchers(MatchFinder *MatchFinder) {
  // Match a floating literal with value 0.5.
  auto FloatHalf = floatLiteral(floatHalf());

  // Match a floating point expression.
  auto FloatType = expr(hasType(realFloatingPointType()));

  // Match a floating literal of 0.5 or a floating literal of 0.5 implicitly.
  // cast to floating type.
  auto FloatOrCastHalf =
      anyOf(FloatHalf, implicitCastExpr(FloatType, has(FloatHalf)));

  // Match if either the LHS or RHS is a floating literal of 0.5 or a floating
  // literal of 0.5 and the other is of type double or vice versa.
  auto OneSideHalf = anyOf(allOf(hasLHS(FloatOrCastHalf), hasRHS(FloatType)),
                           allOf(hasRHS(FloatOrCastHalf), hasLHS(FloatType)));

  // Find expressions of cast to int of the sum of a floating point expression
  // and 0.5.
  MatchFinder->addMatcher(
      implicitCastExpr(
          hasImplicitDestinationType(isInteger()),
          ignoringParenCasts(binaryOperator(hasOperatorName("+"), OneSideHalf)))
          .bind("CastExpr"),
      this);
}
void ProBoundsPointerArithmeticCheck::registerMatchers(MatchFinder *Finder) {
  if (!getLangOpts().CPlusPlus)
    return;

  // Flag all operators +, -, +=, -=, ++, -- that result in a pointer
  Finder->addMatcher(
      binaryOperator(
          anyOf(hasOperatorName("+"), hasOperatorName("-"),
                hasOperatorName("+="), hasOperatorName("-=")),
          hasType(pointerType()),
          unless(hasLHS(ignoringImpCasts(declRefExpr(to(isImplicit()))))))
          .bind("expr"),
      this);

  Finder->addMatcher(
      unaryOperator(anyOf(hasOperatorName("++"), hasOperatorName("--")),
                    hasType(pointerType()))
          .bind("expr"),
      this);

  // Array subscript on a pointer (not an array) is also pointer arithmetic
  Finder->addMatcher(
      arraySubscriptExpr(
          hasBase(ignoringImpCasts(
              anyOf(hasType(pointerType()),
                    hasType(decayedType(hasDecayedType(pointerType())))))))
          .bind("expr"),
      this);
}
void DeleteNullPointerCheck::registerMatchers(MatchFinder *Finder) {
  const auto DeleteExpr =
      cxxDeleteExpr(has(castExpr(has(declRefExpr(
                        to(decl(equalsBoundNode("deletedPointer"))))))))
          .bind("deleteExpr");

  const auto DeleteMemberExpr =
      cxxDeleteExpr(has(castExpr(has(memberExpr(hasDeclaration(
                        fieldDecl(equalsBoundNode("deletedMemberPointer"))))))))
          .bind("deleteMemberExpr");

  const auto PointerExpr = ignoringImpCasts(anyOf(
      declRefExpr(to(decl().bind("deletedPointer"))),
      memberExpr(hasDeclaration(fieldDecl().bind("deletedMemberPointer")))));

  const auto PointerCondition = castExpr(hasCastKind(CK_PointerToBoolean),
                                         hasSourceExpression(PointerExpr));
  const auto BinaryPointerCheckCondition =
      binaryOperator(hasEitherOperand(castExpr(hasCastKind(CK_NullToPointer))),
                     hasEitherOperand(PointerExpr));

  Finder->addMatcher(
      ifStmt(hasCondition(anyOf(PointerCondition, BinaryPointerCheckCondition)),
             hasThen(anyOf(
                 DeleteExpr, DeleteMemberExpr,
                 compoundStmt(anyOf(has(DeleteExpr), has(DeleteMemberExpr)),
                              statementCountIs(1))
                     .bind("compound"))))
          .bind("ifWithDelete"),
      this);
}
void UseEqualsDeleteCheck::registerMatchers(MatchFinder *Finder) {
  auto PrivateSpecialFn = cxxMethodDecl(
      isPrivate(),
      anyOf(cxxConstructorDecl(anyOf(isDefaultConstructor(),
                                     isCopyConstructor(), isMoveConstructor())),
            cxxMethodDecl(
                anyOf(isCopyAssignmentOperator(), isMoveAssignmentOperator())),
            cxxDestructorDecl()));

  Finder->addMatcher(
      cxxMethodDecl(
          PrivateSpecialFn,
          unless(anyOf(hasBody(stmt()), isDefaulted(), isDeleted(),
                       ast_matchers::isTemplateInstantiation(),
                       // Ensure that all methods except private special member
                       // functions are defined.
                       hasParent(cxxRecordDecl(hasMethod(unless(
                           anyOf(PrivateSpecialFn, hasBody(stmt()), isPure(),
                                 isDefaulted(), isDeleted()))))))))
          .bind(SpecialFunction),
      this);

  Finder->addMatcher(
      cxxMethodDecl(isDeleted(), unless(isPublic())).bind(DeletedNotPublic),
      this);
}
void SuspiciousEnumUsageCheck::registerMatchers(MatchFinder *Finder) {
  const auto enumExpr = [](StringRef RefName, StringRef DeclName) {
    return allOf(ignoringImpCasts(expr().bind(RefName)),
                 ignoringImpCasts(hasType(enumDecl().bind(DeclName))));
  };

  Finder->addMatcher(
      binaryOperator(hasOperatorName("|"), hasLHS(enumExpr("", "enumDecl")),
                     hasRHS(allOf(enumExpr("", "otherEnumDecl"),
                                  ignoringImpCasts(hasType(enumDecl(
                                      unless(equalsBoundNode("enumDecl"))))))))
          .bind("diffEnumOp"),
      this);

  Finder->addMatcher(
      binaryOperator(anyOf(hasOperatorName("+"), hasOperatorName("|")),
                     hasLHS(enumExpr("lhsExpr", "enumDecl")),
                     hasRHS(allOf(enumExpr("rhsExpr", ""),
                                  ignoringImpCasts(hasType(enumDecl(
                                      equalsBoundNode("enumDecl"))))))),
      this);

  Finder->addMatcher(
      binaryOperator(anyOf(hasOperatorName("+"), hasOperatorName("|")),
                     hasEitherOperand(
                         allOf(hasType(isInteger()), unless(enumExpr("", "")))),
                     hasEitherOperand(enumExpr("enumExpr", "enumDecl"))),
      this);

  Finder->addMatcher(
      binaryOperator(anyOf(hasOperatorName("|="), hasOperatorName("+=")),
                     hasRHS(enumExpr("enumExpr", "enumDecl"))),
      this);
}
void FasterStringFindCheck::registerMatchers(MatchFinder *Finder) {
  if (!getLangOpts().CPlusPlus)
    return;

  const auto SingleChar =
      expr(ignoringParenCasts(stringLiteral(hasSize(1)).bind("literal")));

  const auto StringFindFunctions =
      anyOf(hasName("find"), hasName("rfind"), hasName("find_first_of"),
            hasName("find_first_not_of"), hasName("find_last_of"),
            hasName("find_last_not_of"));

  llvm::Optional<ast_matchers::internal::Matcher<NamedDecl>> IsStringClass;

  for (const auto &ClassName : StringLikeClasses) {
    const auto HasName = hasName(ClassName);
    IsStringClass = IsStringClass ? anyOf(*IsStringClass, HasName) : HasName;
  }

  if (IsStringClass) {
    Finder->addMatcher(
        cxxMemberCallExpr(
            callee(functionDecl(StringFindFunctions).bind("func")),
            anyOf(argumentCountIs(1), argumentCountIs(2)),
            hasArgument(0, SingleChar),
            on(expr(hasType(recordDecl(*IsStringClass)),
                    unless(hasSubstitutedType())))),
        this);
  }
}
void UseNodiscardCheck::registerMatchers(MatchFinder *Finder) {
  // If we use ``[[nodiscard]]`` attribute, we require at least C++17. Use a
  // macro or ``__attribute__`` with pre c++17 compilers by using
  // ReplacementString option.
  if ((NoDiscardMacro == "[[nodiscard]]" && !getLangOpts().CPlusPlus17) ||
      !getLangOpts().CPlusPlus)
    return;

  auto FunctionObj =
      cxxRecordDecl(hasAnyName("::std::function", "::boost::function"));

  // Find all non-void const methods which have not already been marked to
  // warn on unused result.
  Finder->addMatcher(
      cxxMethodDecl(
          allOf(isConst(), isDefinitionOrInline(),
                unless(anyOf(
                    returns(voidType()), isNoReturn(), isOverloadedOperator(),
                    isVariadic(), hasTemplateReturnType(),
                    hasClassMutableFields(), isConversionOperator(),
                    hasAttr(clang::attr::WarnUnusedResult),
                    hasType(isInstantiationDependentType()),
                    hasAnyParameter(anyOf(
                        parmVarDecl(anyOf(hasType(FunctionObj),
                                          hasType(references(FunctionObj)))),
                        hasType(isNonConstReferenceOrPointer()),
                        hasParameterPack()))))))
          .bind("no_discard"),
      this);
}
void AssignOperatorSignatureCheck::registerMatchers(
    ast_matchers::MatchFinder *Finder) {
  // Only register the matchers for C++; the functionality currently does not
  // provide any benefit to other languages, despite being benign.
  if (getLangOpts().CPlusPlus) {
    const auto HasGoodReturnType = methodDecl(returns(lValueReferenceType(
        pointee(unless(isConstQualified()),
                hasDeclaration(equalsBoundNode("class"))))));

    const auto IsSelf = qualType(anyOf(
        hasDeclaration(equalsBoundNode("class")),
        referenceType(pointee(hasDeclaration(equalsBoundNode("class"))))));
    const auto IsSelfAssign =
        methodDecl(unless(anyOf(isDeleted(), isPrivate(), isImplicit())),
                   hasName("operator="), ofClass(recordDecl().bind("class")),
                   hasParameter(0, parmVarDecl(hasType(IsSelf))))
            .bind("method");

    Finder->addMatcher(
        methodDecl(IsSelfAssign, unless(HasGoodReturnType)).bind("ReturnType"),
        this);

    const auto BadSelf = referenceType(
        anyOf(lValueReferenceType(pointee(unless(isConstQualified()))),
              rValueReferenceType(pointee(isConstQualified()))));

    Finder->addMatcher(
        methodDecl(IsSelfAssign, hasParameter(0, parmVarDecl(hasType(BadSelf))))
            .bind("ArgumentType"),
        this);

    Finder->addMatcher(methodDecl(IsSelfAssign, isConst()).bind("Const"), this);
  }
}
void ContainerSizeEmptyCheck::registerMatchers(MatchFinder *Finder) {
  const auto WrongUse = anyOf(
      hasParent(
          binaryOperator(
              anyOf(has(integerLiteral(equals(0))),
                    allOf(anyOf(hasOperatorName("<"), hasOperatorName(">="),
                                hasOperatorName(">"), hasOperatorName("<=")),
                          hasEitherOperand(integerLiteral(equals(1))))))
              .bind("SizeBinaryOp")),
      hasParent(implicitCastExpr(
          hasImplicitDestinationType(isBoolType()),
          anyOf(
              hasParent(unaryOperator(hasOperatorName("!")).bind("NegOnSize")),
              anything()))),
      hasParent(explicitCastExpr(hasDestinationType(isBoolType()))));

  Finder->addMatcher(
      memberCallExpr(
          on(expr(anyOf(hasType(namedDecl(stlContainer())),
                        hasType(pointsTo(namedDecl(stlContainer()))),
                        hasType(references(namedDecl(stlContainer())))))
                 .bind("STLObject")),
          callee(methodDecl(hasName("size"))), WrongUse).bind("SizeCallExpr"),
      this);
}
void ShrinkToFitCheck::registerMatchers(MatchFinder *Finder) {
  // Swap as a function need not to be considered, because rvalue can not
  // be bound to a non-const reference.
  const auto ShrinkableAsMember =
      memberExpr(member(valueDecl().bind("ContainerDecl")));
  const auto ShrinkableAsDecl =
      declRefExpr(hasDeclaration(valueDecl().bind("ContainerDecl")));
  const auto CopyCtorCall = constructExpr(
      hasArgument(0, anyOf(ShrinkableAsMember, ShrinkableAsDecl,
                           unaryOperator(has(ShrinkableAsMember)),
                           unaryOperator(has(ShrinkableAsDecl)))));
  const auto SwapParam = expr(anyOf(
      memberExpr(member(equalsBoundNode("ContainerDecl"))),
      declRefExpr(hasDeclaration(equalsBoundNode("ContainerDecl"))),
      unaryOperator(has(memberExpr(member(equalsBoundNode("ContainerDecl"))))),
      unaryOperator(
          has(declRefExpr(hasDeclaration(equalsBoundNode("ContainerDecl")))))));

  Finder->addMatcher(
      memberCallExpr(on(hasType(namedDecl(stlShrinkableContainer()))),
                     callee(methodDecl(hasName("swap"))),
                     has(memberExpr(hasDescendant(CopyCtorCall))),
                     hasArgument(0, SwapParam.bind("ContainerToShrink")),
                     unless(isInTemplateInstantiation()))
          .bind("CopyAndSwapTrick"),
      this);
}
Example #15
0
void FunctionSizeCheck::registerMatchers(MatchFinder *Finder) {
  Finder->addMatcher(
      functionDecl(
          unless(isInstantiated()),
          forEachDescendant(
              stmt(unless(compoundStmt()),
                   hasParent(stmt(anyOf(compoundStmt(), ifStmt(),
                                        anyOf(whileStmt(), doStmt(),
                                              forRangeStmt(), forStmt())))))
                  .bind("stmt"))).bind("func"),
      this);
}
void ElseAfterReturnCheck::registerMatchers(MatchFinder *Finder) {
  const auto ControlFlowInterruptorMatcher =
      stmt(anyOf(returnStmt().bind("return"), continueStmt().bind("continue"),
                 breakStmt().bind("break"), cxxThrowExpr().bind("throw")));
  Finder->addMatcher(
      stmt(forEach(
          ifStmt(hasThen(stmt(
                     anyOf(ControlFlowInterruptorMatcher,
                           compoundStmt(has(ControlFlowInterruptorMatcher))))),
                 hasElse(stmt().bind("else")))
              .bind("if"))),
      this);
}
void DefinitionsInHeadersCheck::registerMatchers(MatchFinder *Finder) {
  if (UseHeaderFileExtension) {
    Finder->addMatcher(
        namedDecl(anyOf(functionDecl(isDefinition()), varDecl(isDefinition())),
                  isHeaderFileExtension()).bind("name-decl"),
        this);
  } else {
    Finder->addMatcher(
        namedDecl(anyOf(functionDecl(isDefinition()), varDecl(isDefinition())),
                  anyOf(isHeaderFileExtension(),
                        unless(isExpansionInMainFile()))).bind("name-decl"),
        this);
  }
}
void UseEmplaceCheck::registerMatchers(MatchFinder *Finder) {
  if (!getLangOpts().CPlusPlus11)
    return;

  // FIXME: Bunch of functionality that could be easily added:
  // + add handling of `push_front` for std::forward_list, std::list
  // and std::deque.
  // + add handling of `push` for std::stack, std::queue, std::priority_queue
  // + add handling of `insert` for stl associative container, but be careful
  // because this requires special treatment (it could cause performance
  // regression)
  // + match for emplace calls that should be replaced with insertion
  // + match for make_pair calls.
  auto callPushBack = cxxMemberCallExpr(
      hasDeclaration(functionDecl(hasName("push_back"))),
      on(hasType(cxxRecordDecl(hasAnyName("std::vector", "llvm::SmallVector",
                                          "std::list", "std::deque")))));

  // We can't replace push_backs of smart pointer because
  // if emplacement fails (f.e. bad_alloc in vector) we will have leak of
  // passed pointer because smart pointer won't be constructed
  // (and destructed) as in push_back case.
  auto isCtorOfSmartPtr = hasDeclaration(cxxConstructorDecl(
      ofClass(hasAnyName("std::shared_ptr", "std::unique_ptr", "std::auto_ptr",
                         "std::weak_ptr"))));

  // Bitfields binds only to consts and emplace_back take it by universal ref.
  auto bitFieldAsArgument = hasAnyArgument(ignoringParenImpCasts(
      memberExpr(hasDeclaration(fieldDecl(matchers::isBitfield())))));

  // We could have leak of resource.
  auto newExprAsArgument = hasAnyArgument(ignoringParenImpCasts(cxxNewExpr()));
  auto constructingDerived =
      hasParent(implicitCastExpr(hasCastKind(CastKind::CK_DerivedToBase)));

  auto hasInitList = has(ignoringParenImpCasts(initListExpr()));
  auto soughtConstructExpr =
      cxxConstructExpr(
          unless(anyOf(isCtorOfSmartPtr, hasInitList, bitFieldAsArgument,
                       newExprAsArgument, constructingDerived,
                       has(materializeTemporaryExpr(hasInitList)))))
          .bind("ctor");
  auto hasConstructExpr = has(ignoringParenImpCasts(soughtConstructExpr));

  auto ctorAsArgument = materializeTemporaryExpr(
      anyOf(hasConstructExpr, has(cxxFunctionalCastExpr(hasConstructExpr))));

  Finder->addMatcher(
      cxxMemberCallExpr(callPushBack, has(ctorAsArgument)).bind("call"), this);
}
Example #19
0
void SlicingCheck::registerMatchers(MatchFinder *Finder) {
  // When we see:
  //   class B : public A { ... };
  //   A a;
  //   B b;
  //   a = b;
  // The assignment is OK if:
  //   - the assignment operator is defined as taking a B as second parameter,
  //   or
  //   - B does not define any additional members (either variables or
  //   overrides) wrt A.
  //
  // The same holds for copy ctor calls. This also captures stuff like:
  //   void f(A a);
  //   f(b);

  //  Helpers.
  const auto OfBaseClass = ofClass(cxxRecordDecl().bind("BaseDecl"));
  const auto IsDerivedFromBaseDecl =
      cxxRecordDecl(isDerivedFrom(equalsBoundNode("BaseDecl")))
          .bind("DerivedDecl");
  const auto HasTypeDerivedFromBaseDecl =
      anyOf(hasType(IsDerivedFromBaseDecl),
            hasType(references(IsDerivedFromBaseDecl)));
  const auto IsWithinDerivedCtor =
      hasParent(cxxConstructorDecl(ofClass(equalsBoundNode("DerivedDecl"))));

  // Assignement slicing: "a = b;" and "a = std::move(b);" variants.
  const auto SlicesObjectInAssignment =
      callExpr(callee(cxxMethodDecl(anyOf(isCopyAssignmentOperator(),
                                          isMoveAssignmentOperator()),
                                    OfBaseClass)),
               hasArgument(1, HasTypeDerivedFromBaseDecl));

  // Construction slicing: "A a{b};" and "f(b);" variants. Note that in case of
  // slicing the letter will create a temporary and therefore call a ctor.
  const auto SlicesObjectInCtor = cxxConstructExpr(
      hasDeclaration(cxxConstructorDecl(
          anyOf(isCopyConstructor(), isMoveConstructor()), OfBaseClass)),
      hasArgument(0, HasTypeDerivedFromBaseDecl),
      // We need to disable matching on the call to the base copy/move
      // constructor in DerivedDecl's constructors.
      unless(IsWithinDerivedCtor));

  Finder->addMatcher(
      expr(anyOf(SlicesObjectInAssignment, SlicesObjectInCtor)).bind("Call"),
      this);
}
void NoexceptMoveConstructorCheck::registerMatchers(MatchFinder *Finder) {
    Finder->addMatcher(
        methodDecl(anyOf(constructorDecl(), hasOverloadedOperatorName("=")),
                   unless(isImplicit()), unless(isDeleted()))
        .bind("decl"),
        this);
}
void MultiwayPathsCoveredCheck::registerMatchers(MatchFinder *Finder) {
  Finder->addMatcher(
      switchStmt(
          hasCondition(allOf(
              // Match on switch statements that have either a bit-field or
              // an integer condition. The ordering in 'anyOf()' is
              // important because the last condition is the most general.
              anyOf(ignoringImpCasts(memberExpr(hasDeclaration(
                        fieldDecl(isBitField()).bind("bitfield")))),
                    ignoringImpCasts(declRefExpr().bind("non-enum-condition"))),
              // 'unless()' must be the last match here and must be bound,
              // otherwise the matcher does not work correctly, because it
              // will not explicitly ignore enum conditions.
              unless(ignoringImpCasts(
                  declRefExpr(hasType(enumType())).bind("enum-condition"))))))
          .bind("switch"),
      this);

  // This option is noisy, therefore matching is configurable.
  if (WarnOnMissingElse) {
    Finder->addMatcher(
        ifStmt(allOf(hasParent(ifStmt()), unless(hasElse(anything()))))
            .bind("else-if"),
        this);
  }
}
void NonPrivateMemberVariablesInClassesCheck::registerMatchers(
    MatchFinder *Finder) {
  if (!getLangOpts().CPlusPlus)
    return;

  // We can ignore structs/classes with all member variables being public.
  auto ShouldIgnoreRecord =
      allOf(boolean(IgnoreClassesWithAllMemberVariablesBeingPublic),
            unless(hasNonPublicMemberVariable()));

  // There are three visibility types: public, protected, private.
  // If we are ok with public fields, then we only want to complain about
  // protected fields, else we want to complain about all non-private fields.
  // We can ignore public member variables in structs/classes, in unions.
  auto InterestingField = fieldDecl(
      IgnorePublicMemberVariables ? isProtected() : unless(isPrivate()));

  // We only want the records that not only contain the mutable data (non-static
  // member variables), but also have some logic (non-static member functions).
  // We may optionally ignore records where all the member variables are public.
  Finder->addMatcher(cxxRecordDecl(anyOf(isStruct(), isClass()), hasMethods(),
                                   hasNonStaticMethod(),
                                   unless(ShouldIgnoreRecord),
                                   forEach(InterestingField.bind("field")))
                         .bind("record"),
                     this);
}
void StringReferenceMemberCheck::registerMatchers(
    ast_matchers::MatchFinder *Finder) {
  // Look for const references to std::string or ::string.
  auto String = anyOf(recordDecl(hasName("::std::basic_string")),
                      recordDecl(hasName("::string")));
  auto ConstString = qualType(isConstQualified(), hasDeclaration(String));

  // Ignore members in template instantiations.
  auto InTemplateInstantiation = hasAncestor(
      decl(anyOf(recordDecl(ast_matchers::isTemplateInstantiation()),
                 functionDecl(ast_matchers::isTemplateInstantiation()))));

  Finder->addMatcher(fieldDecl(hasType(references(ConstString)),
                               unless(InTemplateInstantiation)).bind("member"),
                     this);
}
void GlobalNamesInHeadersCheck::registerMatchers(
    ast_matchers::MatchFinder *Finder) {
  Finder->addMatcher(decl(anyOf(usingDecl(), usingDirectiveDecl()),
                          hasDeclContext(translationUnitDecl()))
                         .bind("using_decl"),
                     this);
}
void MisleadingIndentationCheck::registerMatchers(MatchFinder *Finder) {
  Finder->addMatcher(ifStmt(hasElse(stmt())).bind("if"), this);
  Finder->addMatcher(
      compoundStmt(has(stmt(anyOf(ifStmt(), forStmt(), whileStmt()))))
          .bind("compound"),
      this);
}
void RedundantVoidArgCheck::registerMatchers(MatchFinder *Finder) {
  Finder->addMatcher(functionDecl(parameterCountIs(0), unless(isImplicit()),
                                  unless(isExternC()))
                         .bind(FunctionId),
                     this);
  Finder->addMatcher(typedefNameDecl().bind(TypedefId), this);
  auto ParenFunctionType = parenType(innerType(functionType()));
  auto PointerToFunctionType = pointee(ParenFunctionType);
  auto FunctionOrMemberPointer =
      anyOf(hasType(pointerType(PointerToFunctionType)),
            hasType(memberPointerType(PointerToFunctionType)));
  Finder->addMatcher(fieldDecl(FunctionOrMemberPointer).bind(FieldId), this);
  Finder->addMatcher(varDecl(FunctionOrMemberPointer).bind(VarId), this);
  auto CastDestinationIsFunction =
      hasDestinationType(pointsTo(ParenFunctionType));
  Finder->addMatcher(
      cStyleCastExpr(CastDestinationIsFunction).bind(CStyleCastId), this);
  Finder->addMatcher(
      cxxStaticCastExpr(CastDestinationIsFunction).bind(NamedCastId), this);
  Finder->addMatcher(
      cxxReinterpretCastExpr(CastDestinationIsFunction).bind(NamedCastId),
      this);
  Finder->addMatcher(
      cxxConstCastExpr(CastDestinationIsFunction).bind(NamedCastId), this);
  Finder->addMatcher(lambdaExpr().bind(LambdaId), this);
}
void InefficientAlgorithmCheck::registerMatchers(MatchFinder *Finder) {
  // Only register the matchers for C++; the functionality currently does not
  // provide any benefit to other languages, despite being benign.
  if (!getLangOpts().CPlusPlus)
    return;

  const std::string Algorithms =
      "^::std::(find|count|equal_range|lower_bound|upper_bound)$";
  const auto ContainerMatcher = classTemplateSpecializationDecl(
      matchesName("^::std::(unordered_)?(multi)?(set|map)$"));
  const auto Matcher =
      callExpr(
          callee(functionDecl(matchesName(Algorithms))),
          hasArgument(
              0, constructExpr(has(memberCallExpr(
                     callee(methodDecl(hasName("begin"))),
                     on(declRefExpr(
                            hasDeclaration(decl().bind("IneffContObj")),
                            anyOf(hasType(ContainerMatcher.bind("IneffCont")),
                                  hasType(pointsTo(
                                      ContainerMatcher.bind("IneffContPtr")))))
                            .bind("IneffContExpr")))))),
          hasArgument(1, constructExpr(has(memberCallExpr(
                             callee(methodDecl(hasName("end"))),
                             on(declRefExpr(hasDeclaration(
                                 equalsBoundNode("IneffContObj")))))))),
          hasArgument(2, expr().bind("AlgParam")),
          unless(isInTemplateInstantiation()))
          .bind("IneffAlg");

  Finder->addMatcher(Matcher, this);
}
void ElseAfterReturnCheck::registerMatchers(MatchFinder *Finder) {
  // FIXME: Support continue, break and throw.
  Finder->addMatcher(
      ifStmt(
          hasThen(stmt(anyOf(returnStmt(), compoundStmt(has(returnStmt()))))),
          hasElse(stmt().bind("else"))).bind("if"),
      this);
}
void StaticAccessedThroughInstanceCheck::registerMatchers(MatchFinder *Finder) {
  Finder->addMatcher(
      memberExpr(hasDeclaration(anyOf(cxxMethodDecl(isStaticStorageClass()),
                                      varDecl(hasStaticStorageDuration()))),
                 unless(isInTemplateInstantiation()))
          .bind("memberExpression"),
      this);
}
void AssertSideEffectCheck::registerMatchers(MatchFinder *Finder) {
  auto ConditionWithSideEffect =
      hasCondition(hasDescendant(expr(hasSideEffect(CheckFunctionCalls))));
  Finder->addMatcher(
      stmt(anyOf(conditionalOperator(ConditionWithSideEffect),
                 ifStmt(ConditionWithSideEffect))).bind("condStmt"),
      this);
}