258 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "RedundantCastingCheck.h"10#include "../utils/FixItHintUtils.h"11#include "clang/AST/ASTContext.h"12#include "clang/ASTMatchers/ASTMatchFinder.h"13#include "clang/Lex/Lexer.h"14 15using namespace clang::ast_matchers;16 17namespace clang::tidy::readability {18 19static bool areTypesEqual(QualType S, QualType D) {20 if (S == D)21 return true;22 23 const auto *TS = S->getAs<TypedefType>();24 const auto *TD = D->getAs<TypedefType>();25 if (TS != TD)26 return false;27 28 const QualType PtrS = S->getPointeeType();29 const QualType PtrD = D->getPointeeType();30 31 if (!PtrS.isNull() && !PtrD.isNull())32 return areTypesEqual(PtrS, PtrD);33 34 const DeducedType *DT = S->getContainedDeducedType();35 if (DT && DT->isDeduced())36 return D == DT->getDeducedType();37 38 return false;39}40 41static bool areTypesEqual(QualType TypeS, QualType TypeD,42 bool IgnoreTypeAliases) {43 const QualType CTypeS = TypeS.getCanonicalType();44 const QualType CTypeD = TypeD.getCanonicalType();45 if (CTypeS != CTypeD)46 return false;47 48 return IgnoreTypeAliases || areTypesEqual(TypeS.getLocalUnqualifiedType(),49 TypeD.getLocalUnqualifiedType());50}51 52static bool areBinaryOperatorOperandsTypesEqualToOperatorResultType(53 const Expr *E, bool IgnoreTypeAliases) {54 if (!E)55 return true;56 const Expr *WithoutImplicitAndParen = E->IgnoreParenImpCasts();57 if (!WithoutImplicitAndParen)58 return true;59 if (const auto *B = dyn_cast<BinaryOperator>(WithoutImplicitAndParen)) {60 const QualType Type = WithoutImplicitAndParen->getType();61 if (Type.isNull())62 return true;63 64 const QualType NonReferenceType = Type.getNonReferenceType();65 const QualType LHSType = B->getLHS()->IgnoreImplicit()->getType();66 if (LHSType.isNull() || !areTypesEqual(LHSType.getNonReferenceType(),67 NonReferenceType, IgnoreTypeAliases))68 return false;69 const QualType RHSType = B->getRHS()->IgnoreImplicit()->getType();70 if (RHSType.isNull() || !areTypesEqual(RHSType.getNonReferenceType(),71 NonReferenceType, IgnoreTypeAliases))72 return false;73 }74 return true;75}76 77static const Decl *getSourceExprDecl(const Expr *SourceExpr) {78 const Expr *CleanSourceExpr = SourceExpr->IgnoreParenImpCasts();79 if (const auto *E = dyn_cast<DeclRefExpr>(CleanSourceExpr)) {80 return E->getDecl();81 }82 83 if (const auto *E = dyn_cast<CallExpr>(CleanSourceExpr)) {84 return E->getCalleeDecl();85 }86 87 if (const auto *E = dyn_cast<MemberExpr>(CleanSourceExpr)) {88 return E->getMemberDecl();89 }90 return nullptr;91}92 93RedundantCastingCheck::RedundantCastingCheck(StringRef Name,94 ClangTidyContext *Context)95 : ClangTidyCheck(Name, Context),96 IgnoreMacros(Options.get("IgnoreMacros", true)),97 IgnoreTypeAliases(Options.get("IgnoreTypeAliases", false)) {}98 99void RedundantCastingCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {100 Options.store(Opts, "IgnoreMacros", IgnoreMacros);101 Options.store(Opts, "IgnoreTypeAliases", IgnoreTypeAliases);102}103 104void RedundantCastingCheck::registerMatchers(MatchFinder *Finder) {105 auto SimpleType = qualType(hasCanonicalType(106 qualType(anyOf(builtinType(), references(builtinType()),107 references(pointsTo(qualType())), pointsTo(qualType())))));108 109 auto BitfieldMemberExpr = memberExpr(member(fieldDecl(isBitField())));110 111 const ast_matchers::internal::VariadicDynCastAllOfMatcher<112 Stmt, CXXParenListInitExpr>113 cxxParenListInitExpr; // NOLINT(readability-identifier-naming)114 115 Finder->addMatcher(116 explicitCastExpr(117 unless(hasCastKind(CK_ConstructorConversion)),118 unless(hasCastKind(CK_UserDefinedConversion)),119 unless(cxxFunctionalCastExpr(hasDestinationType(unless(SimpleType)))),120 121 hasDestinationType(qualType().bind("dstType")),122 hasSourceExpression(anyOf(123 expr(unless(initListExpr()), unless(BitfieldMemberExpr),124 unless(cxxParenListInitExpr()),125 hasType(qualType().bind("srcType")))126 .bind("source"),127 initListExpr(unless(hasInit(1, expr())),128 hasInit(0, expr(unless(BitfieldMemberExpr),129 hasType(qualType().bind("srcType")))130 .bind("source"))))))131 .bind("cast"),132 this);133}134 135void RedundantCastingCheck::check(const MatchFinder::MatchResult &Result) {136 const auto *SourceExpr = Result.Nodes.getNodeAs<Expr>("source");137 auto TypeD = *Result.Nodes.getNodeAs<QualType>("dstType");138 139 if (SourceExpr->getValueKind() == VK_LValue &&140 TypeD.getCanonicalType()->isRValueReferenceType())141 return;142 143 const auto TypeS =144 Result.Nodes.getNodeAs<QualType>("srcType")->getNonReferenceType();145 TypeD = TypeD.getNonReferenceType();146 147 if (!areTypesEqual(TypeS, TypeD, IgnoreTypeAliases))148 return;149 150 if (!areBinaryOperatorOperandsTypesEqualToOperatorResultType(151 SourceExpr, IgnoreTypeAliases))152 return;153 154 const auto *CastExpr = Result.Nodes.getNodeAs<ExplicitCastExpr>("cast");155 if (IgnoreMacros &&156 (CastExpr->getBeginLoc().isMacroID() ||157 CastExpr->getEndLoc().isMacroID() || CastExpr->getExprLoc().isMacroID()))158 return;159 160 {161 auto Diag = diag(CastExpr->getExprLoc(),162 "redundant explicit casting to the same type %0 as the "163 "sub-expression, remove this casting");164 Diag << TypeD;165 166 const SourceManager &SM = *Result.SourceManager;167 const SourceLocation SourceExprBegin =168 SM.getExpansionLoc(SourceExpr->getBeginLoc());169 const SourceLocation SourceExprEnd =170 SM.getExpansionLoc(SourceExpr->getEndLoc());171 172 if (SourceExprBegin != CastExpr->getBeginLoc())173 Diag << FixItHint::CreateRemoval(SourceRange(174 CastExpr->getBeginLoc(), SourceExprBegin.getLocWithOffset(-1)));175 176 const SourceLocation NextToken = Lexer::getLocForEndOfToken(177 SourceExprEnd, 0U, SM, Result.Context->getLangOpts());178 179 if (SourceExprEnd != CastExpr->getEndLoc()) {180 Diag << FixItHint::CreateRemoval(181 SourceRange(NextToken, CastExpr->getEndLoc()));182 }183 184 if (utils::fixit::areParensNeededForStatement(*SourceExpr)) {185 Diag << FixItHint::CreateInsertion(SourceExprBegin, "(")186 << FixItHint::CreateInsertion(NextToken, ")");187 }188 }189 190 const auto *SourceExprDecl = getSourceExprDecl(SourceExpr);191 if (!SourceExprDecl)192 return;193 194 if (const auto *D = dyn_cast<CXXConstructorDecl>(SourceExprDecl)) {195 diag(D->getLocation(),196 "source type originates from the invocation of this constructor",197 DiagnosticIDs::Note);198 return;199 }200 201 if (const auto *D = dyn_cast<FunctionDecl>(SourceExprDecl)) {202 diag(D->getLocation(),203 "source type originates from the invocation of this "204 "%select{function|method}0",205 DiagnosticIDs::Note)206 << isa<CXXMethodDecl>(D) << D->getReturnTypeSourceRange();207 return;208 }209 210 if (const auto *D = dyn_cast<FieldDecl>(SourceExprDecl)) {211 diag(D->getLocation(),212 "source type originates from referencing this member",213 DiagnosticIDs::Note)214 << SourceRange(D->getTypeSpecStartLoc(), D->getTypeSpecEndLoc());215 return;216 }217 218 if (const auto *D = dyn_cast<ParmVarDecl>(SourceExprDecl)) {219 diag(D->getLocation(),220 "source type originates from referencing this parameter",221 DiagnosticIDs::Note)222 << SourceRange(D->getTypeSpecStartLoc(), D->getTypeSpecEndLoc());223 return;224 }225 226 if (const auto *D = dyn_cast<VarDecl>(SourceExprDecl)) {227 diag(D->getLocation(),228 "source type originates from referencing this variable",229 DiagnosticIDs::Note)230 << SourceRange(D->getTypeSpecStartLoc(), D->getTypeSpecEndLoc());231 return;232 }233 234 if (const auto *D = dyn_cast<EnumConstantDecl>(SourceExprDecl)) {235 diag(D->getLocation(),236 "source type originates from referencing this enum constant",237 DiagnosticIDs::Note);238 return;239 }240 241 if (const auto *D = dyn_cast<BindingDecl>(SourceExprDecl)) {242 diag(D->getLocation(),243 "source type originates from referencing this bound variable",244 DiagnosticIDs::Note);245 return;246 }247 248 if (const auto *D = dyn_cast<NonTypeTemplateParmDecl>(SourceExprDecl)) {249 diag(D->getLocation(),250 "source type originates from referencing this non-type template "251 "parameter",252 DiagnosticIDs::Note);253 return;254 }255}256 257} // namespace clang::tidy::readability258