void NamespaceCommentCheck::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)
Finder->addMatcher(namespaceDecl().bind("namespace"), this);
}
void ProTypeConstCastCheck::registerMatchers(MatchFinder *Finder) {
if (!getLangOpts().CPlusPlus)
return;
Finder->addMatcher(cxxConstCastExpr().bind("cast"), this);
}
void UseOverrideCheck::registerMatchers(MatchFinder *Finder) {
// Only register the matcher for C++11.
if (getLangOpts().CPlusPlus11)
Finder->addMatcher(cxxMethodDecl(isOverride()).bind("method"), this);
}
void UseOverrideCheck::check(const MatchFinder::MatchResult &Result) {
const auto *Method = Result.Nodes.getNodeAs<FunctionDecl>("method");
const SourceManager &Sources = *Result.SourceManager;
assert(Method != nullptr);
if (Method->getInstantiatedFromMemberFunction() != nullptr)
Method = Method->getInstantiatedFromMemberFunction();
if (Method->isImplicit() || Method->getLocation().isMacroID() ||
Method->isOutOfLine())
return;
bool HasVirtual = Method->isVirtualAsWritten();
bool HasOverride = Method->getAttr<OverrideAttr>();
bool HasFinal = Method->getAttr<FinalAttr>();
bool OnlyVirtualSpecified = HasVirtual && !HasOverride && !HasFinal;
unsigned KeywordCount = HasVirtual + HasOverride + HasFinal;
if (!OnlyVirtualSpecified && KeywordCount == 1)
return; // Nothing to do.
std::string Message;
if (OnlyVirtualSpecified) {
Message =
"prefer using 'override' or (rarely) 'final' instead of 'virtual'";
} else if (KeywordCount == 0) {
Message = "annotate this function with 'override' or (rarely) 'final'";
} else {
StringRef Redundant =
HasVirtual ? (HasOverride && HasFinal ? "'virtual' and 'override' are"
: "'virtual' is")
: "'override' is";
StringRef Correct = HasFinal ? "'final'" : "'override'";
Message = (llvm::Twine(Redundant) +
" redundant since the function is already declared " + Correct)
.str();
}
DiagnosticBuilder Diag = diag(Method->getLocation(), Message);
CharSourceRange FileRange = Lexer::makeFileCharRange(
CharSourceRange::getTokenRange(Method->getSourceRange()), Sources,
getLangOpts());
if (!FileRange.isValid())
return;
// FIXME: Instead of re-lexing and looking for specific macros such as
// 'ABSTRACT', properly store the location of 'virtual' and '= 0' in each
// FunctionDecl.
SmallVector<Token, 16> Tokens = ParseTokens(FileRange, Result);
// Add 'override' on inline declarations that don't already have it.
if (!HasFinal && !HasOverride) {
SourceLocation InsertLoc;
StringRef ReplacementText = "override ";
SourceLocation MethodLoc = Method->getLocation();
for (Token T : Tokens) {
if (T.is(tok::kw___attribute) &&
!Sources.isBeforeInTranslationUnit(T.getLocation(), MethodLoc)) {
InsertLoc = T.getLocation();
break;
}
}
if (Method->hasAttrs()) {
for (const clang::Attr *A : Method->getAttrs()) {
if (!A->isImplicit() && !A->isInherited()) {
SourceLocation Loc =
Sources.getExpansionLoc(A->getRange().getBegin());
if ((!InsertLoc.isValid() ||
Sources.isBeforeInTranslationUnit(Loc, InsertLoc)) &&
!Sources.isBeforeInTranslationUnit(Loc, MethodLoc))
InsertLoc = Loc;
}
}
}
if (InsertLoc.isInvalid() && Method->doesThisDeclarationHaveABody() &&
Method->getBody() && !Method->isDefaulted()) {
// For methods with inline definition, add the override keyword at the
// end of the declaration of the function, but prefer to put it on the
// same line as the declaration if the beginning brace for the start of
// the body falls on the next line.
Token LastNonCommentToken;
for (Token T : Tokens) {
if (!T.is(tok::comment)) {
LastNonCommentToken = T;
}
}
InsertLoc = LastNonCommentToken.getEndLoc();
ReplacementText = " override";
}
if (!InsertLoc.isValid()) {
// For declarations marked with "= 0" or "= [default|delete]", the end
// location will point until after those markings. Therefore, the override
// keyword shouldn't be inserted at the end, but before the '='.
if (Tokens.size() > 2 && (GetText(Tokens.back(), Sources) == "0" ||
Tokens.back().is(tok::kw_default) ||
Tokens.back().is(tok::kw_delete)) &&
GetText(Tokens[Tokens.size() - 2], Sources) == "=") {
InsertLoc = Tokens[Tokens.size() - 2].getLocation();
// Check if we need to insert a space.
if ((Tokens[Tokens.size() - 2].getFlags() & Token::LeadingSpace) == 0)
ReplacementText = " override ";
} else if (GetText(Tokens.back(), Sources) == "ABSTRACT") {
InsertLoc = Tokens.back().getLocation();
}
}
if (!InsertLoc.isValid()) {
InsertLoc = FileRange.getEnd();
ReplacementText = " override";
}
Diag << FixItHint::CreateInsertion(InsertLoc, ReplacementText);
}
if (HasFinal && HasOverride) {
SourceLocation OverrideLoc = Method->getAttr<OverrideAttr>()->getLocation();
Diag << FixItHint::CreateRemoval(
CharSourceRange::getTokenRange(OverrideLoc, OverrideLoc));
}
if (HasVirtual) {
for (Token Tok : Tokens) {
if (Tok.is(tok::kw_virtual)) {
Diag << FixItHint::CreateRemoval(CharSourceRange::getTokenRange(
Tok.getLocation(), Tok.getLocation()));
break;
}
}
}
}
void UnaryStaticAssertCheck::registerMatchers(MatchFinder *Finder) {
if (!getLangOpts().CPlusPlus17)
return;
Finder->addMatcher(staticAssertDecl().bind("static_assert"), this);
}
void UpgradeDurationConversionsCheck::registerMatchers(MatchFinder *Finder) {
if (!getLangOpts().CPlusPlus)
return;
// For the arithmetic calls, we match only the uses of the templated operators
// where the template parameter is not a built-in type. This means the
// instantiation makes use of an available user defined conversion to
// `int64_t`.
//
// The implementation of these templates will be updated to fail SFINAE for
// non-integral types. We match them to suggest an explicit cast.
// Match expressions like `a *= b` and `a /= b` where `a` has type
// `absl::Duration` and `b` is not of a built-in type.
Finder->addMatcher(
cxxOperatorCallExpr(
argumentCountIs(2),
hasArgument(
0, expr(hasType(cxxRecordDecl(hasName("::absl::Duration"))))),
hasArgument(1, expr().bind("arg")),
callee(functionDecl(
hasParent(functionTemplateDecl()),
unless(hasTemplateArgument(0, refersToType(builtinType()))),
hasAnyName("operator*=", "operator/=")))),
this);
// Match expressions like `a.operator*=(b)` and `a.operator/=(b)` where `a`
// has type `absl::Duration` and `b` is not of a built-in type.
Finder->addMatcher(
cxxMemberCallExpr(
callee(cxxMethodDecl(
ofClass(cxxRecordDecl(hasName("::absl::Duration"))),
hasParent(functionTemplateDecl()),
unless(hasTemplateArgument(0, refersToType(builtinType()))),
hasAnyName("operator*=", "operator/="))),
argumentCountIs(1), hasArgument(0, expr().bind("arg"))),
this);
// Match expressions like `a * b`, `a / b`, `operator*(a, b)`, and
// `operator/(a, b)` where `a` has type `absl::Duration` and `b` is not of a
// built-in type.
Finder->addMatcher(
callExpr(callee(functionDecl(
hasParent(functionTemplateDecl()),
unless(hasTemplateArgument(0, refersToType(builtinType()))),
hasAnyName("::absl::operator*", "::absl::operator/"))),
argumentCountIs(2),
hasArgument(0, expr(hasType(
cxxRecordDecl(hasName("::absl::Duration"))))),
hasArgument(1, expr().bind("arg"))),
this);
// Match expressions like `a * b` and `operator*(a, b)` where `a` is not of a
// built-in type and `b` has type `absl::Duration`.
Finder->addMatcher(
callExpr(callee(functionDecl(
hasParent(functionTemplateDecl()),
unless(hasTemplateArgument(0, refersToType(builtinType()))),
hasName("::absl::operator*"))),
argumentCountIs(2), hasArgument(0, expr().bind("arg")),
hasArgument(1, expr(hasType(cxxRecordDecl(
hasName("::absl::Duration")))))),
this);
// For the factory functions, we match only the non-templated overloads that
// take an `int64_t` parameter. Within these calls, we care about implicit
// casts through a user defined conversion to `int64_t`.
//
// The factory functions will be updated to be templated and SFINAE on whether
// the template parameter is an integral type. This complements the already
// existing templated overloads that only accept floating point types.
// Match calls like:
// `absl::Nanoseconds(x)`
// `absl::Microseconds(x)`
// `absl::Milliseconds(x)`
// `absl::Seconds(x)`
// `absl::Minutes(x)`
// `absl::Hours(x)`
// where `x` is not of a built-in type.
Finder->addMatcher(
implicitCastExpr(
anyOf(hasCastKind(CK_UserDefinedConversion),
has(implicitCastExpr(hasCastKind(CK_UserDefinedConversion)))),
hasParent(callExpr(
callee(functionDecl(DurationFactoryFunction(),
unless(hasParent(functionTemplateDecl())))),
hasArgument(0, expr().bind("arg"))))),
this);
}
void ContainerSizeEmptyCheck::check(const MatchFinder::MatchResult &Result) {
const auto *MemberCall =
Result.Nodes.getNodeAs<CXXMemberCallExpr>("SizeCallExpr");
const auto *BinaryOp = Result.Nodes.getNodeAs<BinaryOperator>("SizeBinaryOp");
const auto *E = Result.Nodes.getNodeAs<Expr>("STLObject");
FixItHint Hint;
std::string ReplacementText =
Lexer::getSourceText(CharSourceRange::getTokenRange(E->getSourceRange()),
*Result.SourceManager, getLangOpts());
if (E->getType()->isPointerType())
ReplacementText += "->empty()";
else
ReplacementText += ".empty()";
if (BinaryOp) { // Determine the correct transformation.
bool Negation = false;
const bool ContainerIsLHS =
!llvm::isa<IntegerLiteral>(BinaryOp->getLHS()->IgnoreImpCasts());
const auto OpCode = BinaryOp->getOpcode();
uint64_t Value = 0;
if (ContainerIsLHS) {
if (const auto *Literal = llvm::dyn_cast<IntegerLiteral>(
BinaryOp->getRHS()->IgnoreImpCasts()))
Value = Literal->getValue().getLimitedValue();
else
return;
} else {
Value =
llvm::dyn_cast<IntegerLiteral>(BinaryOp->getLHS()->IgnoreImpCasts())
->getValue()
.getLimitedValue();
}
// Constant that is not handled.
if (Value > 1)
return;
if (Value == 1 && (OpCode == BinaryOperatorKind::BO_EQ ||
OpCode == BinaryOperatorKind::BO_NE))
return;
// Always true, no warnings for that.
if ((OpCode == BinaryOperatorKind::BO_GE && Value == 0 && ContainerIsLHS) ||
(OpCode == BinaryOperatorKind::BO_LE && Value == 0 && !ContainerIsLHS))
return;
// Do not warn for size > 1, 1 < size, size <= 1, 1 >= size.
if (Value == 1) {
if ((OpCode == BinaryOperatorKind::BO_GT && ContainerIsLHS) ||
(OpCode == BinaryOperatorKind::BO_LT && !ContainerIsLHS))
return;
if ((OpCode == BinaryOperatorKind::BO_LE && ContainerIsLHS) ||
(OpCode == BinaryOperatorKind::BO_GE && !ContainerIsLHS))
return;
}
if (OpCode == BinaryOperatorKind::BO_NE && Value == 0)
Negation = true;
if ((OpCode == BinaryOperatorKind::BO_GT ||
OpCode == BinaryOperatorKind::BO_GE) &&
ContainerIsLHS)
Negation = true;
if ((OpCode == BinaryOperatorKind::BO_LT ||
OpCode == BinaryOperatorKind::BO_LE) &&
!ContainerIsLHS)
Negation = true;
if (Negation)
ReplacementText = "!" + ReplacementText;
Hint = FixItHint::CreateReplacement(BinaryOp->getSourceRange(),
ReplacementText);
} else {
// If there is a conversion above the size call to bool, it is safe to just
// replace size with empty.
if (const auto *UnaryOp =
Result.Nodes.getNodeAs<UnaryOperator>("NegOnSize"))
Hint = FixItHint::CreateReplacement(UnaryOp->getSourceRange(),
ReplacementText);
else
Hint = FixItHint::CreateReplacement(MemberCall->getSourceRange(),
"!" + ReplacementText);
}
diag(MemberCall->getLocStart(), "the 'empty' method should be used to check "
"for emptiness instead of 'size'")
<< Hint;
const auto *Container = Result.Nodes.getNodeAs<NamedDecl>("container");
const auto *Empty = Result.Nodes.getNodeAs<FunctionDecl>("empty");
diag(Empty->getLocation(), "method %0::empty() defined here",
DiagnosticIDs::Note)
<< Container;
}
void ProTypeCstyleCastCheck::check(const MatchFinder::MatchResult &Result) {
const auto *MatchedCast = Result.Nodes.getNodeAs<CStyleCastExpr>("cast");
if (MatchedCast->getCastKind() == CK_BitCast ||
MatchedCast->getCastKind() == CK_LValueBitCast ||
MatchedCast->getCastKind() == CK_IntegralToPointer ||
MatchedCast->getCastKind() == CK_PointerToIntegral ||
MatchedCast->getCastKind() == CK_ReinterpretMemberPointer) {
diag(MatchedCast->getLocStart(),
"do not use C-style cast to convert between unrelated types");
return;
}
QualType SourceType = MatchedCast->getSubExpr()->getType();
if (MatchedCast->getCastKind() == CK_BaseToDerived) {
const auto *SourceDecl = SourceType->getPointeeCXXRecordDecl();
if (!SourceDecl) // The cast is from object to reference.
SourceDecl = SourceType->getAsCXXRecordDecl();
if (!SourceDecl)
return;
if (SourceDecl->isPolymorphic()) {
// Leave type spelling exactly as it was (unlike
// getTypeAsWritten().getAsString() which would spell enum types 'enum
// X').
StringRef DestTypeString = Lexer::getSourceText(
CharSourceRange::getTokenRange(
MatchedCast->getLParenLoc().getLocWithOffset(1),
MatchedCast->getRParenLoc().getLocWithOffset(-1)),
*Result.SourceManager, getLangOpts());
auto diag_builder = diag(
MatchedCast->getLocStart(),
"do not use C-style cast to downcast from a base to a derived class; "
"use dynamic_cast instead");
const Expr *SubExpr =
MatchedCast->getSubExprAsWritten()->IgnoreImpCasts();
std::string CastText = ("dynamic_cast<" + DestTypeString + ">").str();
if (!isa<ParenExpr>(SubExpr)) {
CastText.push_back('(');
diag_builder << FixItHint::CreateInsertion(
Lexer::getLocForEndOfToken(SubExpr->getLocEnd(), 0,
*Result.SourceManager, getLangOpts()),
")");
}
auto ParenRange = CharSourceRange::getTokenRange(
MatchedCast->getLParenLoc(), MatchedCast->getRParenLoc());
diag_builder << FixItHint::CreateReplacement(ParenRange, CastText);
} else {
diag(
MatchedCast->getLocStart(),
"do not use C-style cast to downcast from a base to a derived class");
}
return;
}
if (MatchedCast->getCastKind() == CK_NoOp &&
needsConstCast(SourceType, MatchedCast->getType())) {
diag(MatchedCast->getLocStart(),
"do not use C-style cast to cast away constness");
}
}
void AvoidCStyleCastsCheck::check(const MatchFinder::MatchResult &Result) {
const auto *CastExpr = Result.Nodes.getNodeAs<CStyleCastExpr>("cast");
// Ignore casts in macros.
if (CastExpr->getExprLoc().isMacroID())
return;
// Casting to void is an idiomatic way to mute "unused variable" and similar
// warnings.
if (CastExpr->getCastKind() == CK_ToVoid)
return;
auto isFunction = [](QualType T) {
T = T.getCanonicalType().getNonReferenceType();
return T->isFunctionType() || T->isFunctionPointerType() ||
T->isMemberFunctionPointerType();
};
const QualType DestTypeAsWritten =
CastExpr->getTypeAsWritten().getUnqualifiedType();
const QualType SourceTypeAsWritten =
CastExpr->getSubExprAsWritten()->getType().getUnqualifiedType();
const QualType SourceType = SourceTypeAsWritten.getCanonicalType();
const QualType DestType = DestTypeAsWritten.getCanonicalType();
auto ReplaceRange = CharSourceRange::getCharRange(
CastExpr->getLParenLoc(), CastExpr->getSubExprAsWritten()->getBeginLoc());
bool FnToFnCast =
isFunction(SourceTypeAsWritten) && isFunction(DestTypeAsWritten);
if (CastExpr->getCastKind() == CK_NoOp && !FnToFnCast) {
// Function pointer/reference casts may be needed to resolve ambiguities in
// case of overloaded functions, so detection of redundant casts is trickier
// in this case. Don't emit "redundant cast" warnings for function
// pointer/reference types.
if (SourceTypeAsWritten == DestTypeAsWritten) {
diag(CastExpr->getBeginLoc(), "redundant cast to the same type")
<< FixItHint::CreateRemoval(ReplaceRange);
return;
}
}
// The rest of this check is only relevant to C++.
// We also disable it for Objective-C++.
if (!getLangOpts().CPlusPlus || getLangOpts().ObjC1 || getLangOpts().ObjC2)
return;
// Ignore code inside extern "C" {} blocks.
if (!match(expr(hasAncestor(linkageSpecDecl())), *CastExpr, *Result.Context)
.empty())
return;
// Ignore code in .c files and headers included from them, even if they are
// compiled as C++.
if (getCurrentMainFile().endswith(".c"))
return;
SourceManager &SM = *Result.SourceManager;
// Ignore code in .c files #included in other files (which shouldn't be done,
// but people still do this for test and other purposes).
if (SM.getFilename(SM.getSpellingLoc(CastExpr->getBeginLoc())).endswith(".c"))
return;
// Leave type spelling exactly as it was (unlike
// getTypeAsWritten().getAsString() which would spell enum types 'enum X').
StringRef DestTypeString =
Lexer::getSourceText(CharSourceRange::getTokenRange(
CastExpr->getLParenLoc().getLocWithOffset(1),
CastExpr->getRParenLoc().getLocWithOffset(-1)),
SM, getLangOpts());
auto Diag =
diag(CastExpr->getBeginLoc(), "C-style casts are discouraged; use %0");
auto ReplaceWithCast = [&](std::string CastText) {
const Expr *SubExpr = CastExpr->getSubExprAsWritten()->IgnoreImpCasts();
if (!isa<ParenExpr>(SubExpr)) {
CastText.push_back('(');
Diag << FixItHint::CreateInsertion(
Lexer::getLocForEndOfToken(SubExpr->getEndLoc(), 0, SM,
getLangOpts()),
")");
}
Diag << FixItHint::CreateReplacement(ReplaceRange, CastText);
};
auto ReplaceWithNamedCast = [&](StringRef CastType) {
Diag << CastType;
ReplaceWithCast((CastType + "<" + DestTypeString + ">").str());
};
// Suggest appropriate C++ cast. See [expr.cast] for cast notation semantics.
switch (CastExpr->getCastKind()) {
case CK_FunctionToPointerDecay:
ReplaceWithNamedCast("static_cast");
return;
case CK_ConstructorConversion:
if (!CastExpr->getTypeAsWritten().hasQualifiers() &&
DestTypeAsWritten->isRecordType() &&
!DestTypeAsWritten->isElaboratedTypeSpecifier()) {
Diag << "constructor call syntax";
// FIXME: Validate DestTypeString, maybe.
ReplaceWithCast(DestTypeString.str());
} else {
ReplaceWithNamedCast("static_cast");
}
return;
case CK_NoOp:
if (FnToFnCast) {
ReplaceWithNamedCast("static_cast");
return;
}
if (SourceType == DestType) {
Diag << "static_cast (if needed, the cast may be redundant)";
ReplaceWithCast(("static_cast<" + DestTypeString + ">").str());
return;
}
if (needsConstCast(SourceType, DestType) &&
pointedUnqualifiedTypesAreEqual(SourceType, DestType)) {
ReplaceWithNamedCast("const_cast");
return;
}
if (DestType->isReferenceType()) {
QualType Dest = DestType.getNonReferenceType();
QualType Source = SourceType.getNonReferenceType();
if (Source == Dest.withConst() ||
SourceType.getNonReferenceType() == DestType.getNonReferenceType()) {
ReplaceWithNamedCast("const_cast");
return;
}
break;
}
// FALLTHROUGH
case clang::CK_IntegralCast:
// Convert integral and no-op casts between builtin types and enums to
// static_cast. A cast from enum to integer may be unnecessary, but it's
// still retained.
if ((SourceType->isBuiltinType() || SourceType->isEnumeralType()) &&
(DestType->isBuiltinType() || DestType->isEnumeralType())) {
ReplaceWithNamedCast("static_cast");
return;
}
break;
case CK_BitCast:
// FIXME: Suggest const_cast<...>(reinterpret_cast<...>(...)) replacement.
if (!needsConstCast(SourceType, DestType)) {
if (SourceType->isVoidPointerType())
ReplaceWithNamedCast("static_cast");
else
ReplaceWithNamedCast("reinterpret_cast");
return;
}
break;
default:
break;
}
Diag << "static_cast/const_cast/reinterpret_cast";
}
void UseUsingCheck::registerMatchers(MatchFinder *Finder) {
if (!getLangOpts().CPlusPlus11)
return;
Finder->addMatcher(typedefDecl().bind("typedef"), this);
}
void ExplicitConstructorCheck::check(const MatchFinder::MatchResult &Result) {
constexpr char WarningMessage[] =
"%0 must be marked explicit to avoid unintentional implicit conversions";
if (const auto *Conversion =
Result.Nodes.getNodeAs<CXXConversionDecl>("conversion")) {
if (Conversion->isOutOfLine())
return;
SourceLocation Loc = Conversion->getLocation();
// Ignore all macros until we learn to ignore specific ones (e.g. used in
// gmock to define matchers).
if (Loc.isMacroID())
return;
diag(Loc, WarningMessage)
<< Conversion << FixItHint::CreateInsertion(Loc, "explicit ");
return;
}
const auto *Ctor = Result.Nodes.getNodeAs<CXXConstructorDecl>("ctor");
if (Ctor->isOutOfLine() || Ctor->getNumParams() == 0 ||
Ctor->getMinRequiredArguments() > 1)
return;
bool takesInitializerList = isStdInitializerList(
Ctor->getParamDecl(0)->getType().getNonReferenceType());
if (Ctor->isExplicit() &&
(Ctor->isCopyOrMoveConstructor() || takesInitializerList)) {
auto isKWExplicit = [](const Token &Tok) {
return Tok.is(tok::raw_identifier) &&
Tok.getRawIdentifier() == "explicit";
};
SourceRange ExplicitTokenRange =
FindToken(*Result.SourceManager, getLangOpts(),
Ctor->getOuterLocStart(), Ctor->getEndLoc(), isKWExplicit);
StringRef ConstructorDescription;
if (Ctor->isMoveConstructor())
ConstructorDescription = "move";
else if (Ctor->isCopyConstructor())
ConstructorDescription = "copy";
else
ConstructorDescription = "initializer-list";
auto Diag = diag(Ctor->getLocation(),
"%0 constructor should not be declared explicit")
<< ConstructorDescription;
if (ExplicitTokenRange.isValid()) {
Diag << FixItHint::CreateRemoval(
CharSourceRange::getCharRange(ExplicitTokenRange));
}
return;
}
if (Ctor->isExplicit() || Ctor->isCopyOrMoveConstructor() ||
takesInitializerList)
return;
bool SingleArgument =
Ctor->getNumParams() == 1 && !Ctor->getParamDecl(0)->isParameterPack();
SourceLocation Loc = Ctor->getLocation();
diag(Loc, WarningMessage)
<< (SingleArgument
? "single-argument constructors"
: "constructors that are callable with a single argument")
<< FixItHint::CreateInsertion(Loc, "explicit ");
}