11 #include "clang/Frontend/CompilerInstance.h"
12 #include "clang/Lex/Lexer.h"
14 using namespace clang::ast_matchers;
23 bool protoTypeHasNoParms(QualType QT) {
24 if (
auto PT = QT->getAs<PointerType>()) {
25 QT = PT->getPointeeType();
27 if (
auto *MPT = QT->getAs<MemberPointerType>()) {
28 QT = MPT->getPointeeType();
30 if (
auto FP = QT->getAs<FunctionProtoType>()) {
31 return FP->getNumParams() == 0;
36 const char FunctionId[] =
"function";
37 const char TypedefId[] =
"typedef";
38 const char FieldId[] =
"field";
39 const char VarId[] =
"var";
40 const char NamedCastId[] =
"named-cast";
41 const char CStyleCastId[] =
"c-style-cast";
42 const char ExplicitCastId[] =
"explicit-cast";
43 const char LambdaId[] =
"lambda";
47 void RedundantVoidArgCheck::registerMatchers(MatchFinder *
Finder) {
48 if (!getLangOpts().CPlusPlus)
51 Finder->addMatcher(functionDecl(parameterCountIs(0), unless(isImplicit()),
55 Finder->addMatcher(typedefNameDecl().bind(TypedefId),
this);
56 auto ParenFunctionType = parenType(innerType(functionType()));
57 auto PointerToFunctionType = pointee(ParenFunctionType);
58 auto FunctionOrMemberPointer =
59 anyOf(hasType(pointerType(PointerToFunctionType)),
60 hasType(memberPointerType(PointerToFunctionType)));
61 Finder->addMatcher(fieldDecl(FunctionOrMemberPointer).bind(FieldId),
this);
62 Finder->addMatcher(varDecl(FunctionOrMemberPointer).bind(VarId),
this);
63 auto CastDestinationIsFunction =
64 hasDestinationType(pointsTo(ParenFunctionType));
66 cStyleCastExpr(CastDestinationIsFunction).bind(CStyleCastId),
this);
68 cxxStaticCastExpr(CastDestinationIsFunction).bind(NamedCastId),
this);
70 cxxReinterpretCastExpr(CastDestinationIsFunction).bind(NamedCastId),
73 cxxConstCastExpr(CastDestinationIsFunction).bind(NamedCastId),
this);
74 Finder->addMatcher(lambdaExpr().bind(LambdaId),
this);
77 void RedundantVoidArgCheck::check(
const MatchFinder::MatchResult &
Result) {
78 const BoundNodes &Nodes = Result.Nodes;
79 if (
const auto *Function = Nodes.getNodeAs<FunctionDecl>(FunctionId)) {
80 processFunctionDecl(Result, Function);
81 }
else if (
const auto *TypedefName =
82 Nodes.getNodeAs<TypedefNameDecl>(TypedefId)) {
83 processTypedefNameDecl(Result, TypedefName);
84 }
else if (
const auto *Member = Nodes.getNodeAs<FieldDecl>(FieldId)) {
85 processFieldDecl(Result, Member);
86 }
else if (
const auto *Var = Nodes.getNodeAs<VarDecl>(VarId)) {
87 processVarDecl(Result, Var);
88 }
else if (
const auto *NamedCast =
89 Nodes.getNodeAs<CXXNamedCastExpr>(NamedCastId)) {
90 processNamedCastExpr(Result, NamedCast);
91 }
else if (
const auto *CStyleCast =
92 Nodes.getNodeAs<CStyleCastExpr>(CStyleCastId)) {
93 processExplicitCastExpr(Result, CStyleCast);
94 }
else if (
const auto *ExplicitCast =
95 Nodes.getNodeAs<ExplicitCastExpr>(ExplicitCastId)) {
96 processExplicitCastExpr(Result, ExplicitCast);
97 }
else if (
const auto *Lambda = Nodes.getNodeAs<LambdaExpr>(LambdaId)) {
98 processLambdaExpr(Result, Lambda);
102 void RedundantVoidArgCheck::processFunctionDecl(
103 const MatchFinder::MatchResult &
Result,
const FunctionDecl *Function) {
104 if (Function->isThisDeclarationADefinition()) {
105 const Stmt *Body = Function->getBody();
106 SourceLocation Start = Function->getLocStart();
108 Body ? Body->getLocStart().getLocWithOffset(-1) : Function->getLocEnd();
109 removeVoidArgumentTokens(Result, SourceRange(Start, End),
110 "function definition");
112 removeVoidArgumentTokens(Result, Function->getSourceRange(),
113 "function declaration");
117 void RedundantVoidArgCheck::removeVoidArgumentTokens(
118 const ast_matchers::MatchFinder::MatchResult &Result, SourceRange
Range,
119 StringRef GrammarLocation) {
120 CharSourceRange CharRange =
121 Lexer::makeFileCharRange(CharSourceRange::getTokenRange(Range),
122 *Result.SourceManager, getLangOpts());
124 std::string DeclText =
125 Lexer::getSourceText(CharRange, *Result.SourceManager, getLangOpts())
127 Lexer PrototypeLexer(CharRange.getBegin(), getLangOpts(), DeclText.data(),
128 DeclText.data(), DeclText.data() + DeclText.size());
134 TokenState State = NothingYet;
137 std::string Diagnostic =
138 (
"redundant void argument list in " + GrammarLocation).str();
140 while (!PrototypeLexer.LexFromRawLexer(ProtoToken)) {
143 if (ProtoToken.is(tok::TokenKind::l_paren)) {
144 State = SawLeftParen;
148 if (ProtoToken.is(tok::TokenKind::raw_identifier) &&
149 ProtoToken.getRawIdentifier() ==
"void") {
151 VoidToken = ProtoToken;
158 if (ProtoToken.is(tok::TokenKind::r_paren)) {
159 removeVoidToken(VoidToken, Diagnostic);
160 }
else if (ProtoToken.is(tok::TokenKind::l_paren)) {
161 State = SawLeftParen;
167 if (State == SawVoid && ProtoToken.is(tok::TokenKind::r_paren)) {
168 removeVoidToken(VoidToken, Diagnostic);
172 void RedundantVoidArgCheck::removeVoidToken(Token VoidToken,
173 StringRef Diagnostic) {
174 SourceLocation VoidLoc(VoidToken.getLocation());
176 CharSourceRange::getTokenRange(VoidLoc, VoidLoc.getLocWithOffset(3));
177 diag(VoidLoc, Diagnostic) << FixItHint::CreateRemoval(VoidRange);
180 void RedundantVoidArgCheck::processTypedefNameDecl(
181 const MatchFinder::MatchResult &Result,
182 const TypedefNameDecl *TypedefName) {
183 if (protoTypeHasNoParms(TypedefName->getUnderlyingType())) {
184 removeVoidArgumentTokens(Result, TypedefName->getSourceRange(),
185 isa<TypedefDecl>(TypedefName) ?
"typedef"
190 void RedundantVoidArgCheck::processFieldDecl(
191 const MatchFinder::MatchResult &Result,
const FieldDecl *Member) {
192 if (protoTypeHasNoParms(Member->getType())) {
193 removeVoidArgumentTokens(Result, Member->getSourceRange(),
194 "field declaration");
198 void RedundantVoidArgCheck::processVarDecl(
199 const MatchFinder::MatchResult &Result,
const VarDecl *Var) {
200 if (protoTypeHasNoParms(Var->getType())) {
201 SourceLocation Begin = Var->getLocStart();
202 if (Var->hasInit()) {
203 SourceLocation InitStart =
204 Result.SourceManager->getExpansionLoc(Var->getInit()->getLocStart())
205 .getLocWithOffset(-1);
206 removeVoidArgumentTokens(Result, SourceRange(Begin, InitStart),
207 "variable declaration with initializer");
209 removeVoidArgumentTokens(Result, Var->getSourceRange(),
210 "variable declaration");
215 void RedundantVoidArgCheck::processNamedCastExpr(
216 const MatchFinder::MatchResult &Result,
const CXXNamedCastExpr *NamedCast) {
217 if (protoTypeHasNoParms(NamedCast->getTypeAsWritten())) {
218 removeVoidArgumentTokens(
220 NamedCast->getTypeInfoAsWritten()->getTypeLoc().getSourceRange(),
225 void RedundantVoidArgCheck::processExplicitCastExpr(
226 const MatchFinder::MatchResult &Result,
227 const ExplicitCastExpr *ExplicitCast) {
228 if (protoTypeHasNoParms(ExplicitCast->getTypeAsWritten())) {
229 removeVoidArgumentTokens(Result, ExplicitCast->getSourceRange(),
234 void RedundantVoidArgCheck::processLambdaExpr(
235 const MatchFinder::MatchResult &Result,
const LambdaExpr *Lambda) {
236 if (Lambda->getLambdaClass()->getLambdaCallOperator()->getNumParams() == 0 &&
237 Lambda->hasExplicitParameters()) {
238 SourceLocation Begin =
239 Lambda->getIntroducerRange().getEnd().getLocWithOffset(1);
240 SourceLocation End = Lambda->getBody()->getLocStart().getLocWithOffset(-1);
241 removeVoidArgumentTokens(Result, SourceRange(Begin, End),
242 "lambda expression");
std::unique_ptr< ast_matchers::MatchFinder > Finder
CharSourceRange Range
SourceRange for the file name.