76 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 "MisplacedConstCheck.h"10#include "clang/AST/ASTContext.h"11#include "clang/ASTMatchers/ASTMatchFinder.h"12 13using namespace clang::ast_matchers;14 15namespace clang::tidy::misc {16 17void MisplacedConstCheck::registerMatchers(MatchFinder *Finder) {18 auto NonConstAndNonFunctionPointerType = hasType(pointerType(unless(19 pointee(anyOf(isConstQualified(), ignoringParens(functionType()))))));20 21 Finder->addMatcher(22 valueDecl(23 hasType(qualType(isConstQualified(),24 typedefType(hasDeclaration(anyOf(25 typedefDecl(NonConstAndNonFunctionPointerType)26 .bind("typedef"),27 typeAliasDecl(NonConstAndNonFunctionPointerType)28 .bind("typeAlias")))))))29 .bind("decl"),30 this);31}32 33static QualType guessAlternateQualification(ASTContext &Context, QualType QT) {34 // We're given a QualType from a typedef where the qualifiers apply to the35 // pointer instead of the pointee. Strip the const qualifier from the pointer36 // type and add it to the pointee instead.37 if (!QT->isPointerType())38 return QT;39 40 Qualifiers Quals = QT.getLocalQualifiers();41 Quals.removeConst();42 43 const QualType NewQT = Context.getPointerType(44 QualType(QT->getPointeeType().getTypePtr(), Qualifiers::Const));45 return NewQT.withCVRQualifiers(Quals.getCVRQualifiers());46}47 48void MisplacedConstCheck::check(const MatchFinder::MatchResult &Result) {49 const auto *Var = Result.Nodes.getNodeAs<ValueDecl>("decl");50 ASTContext &Ctx = *Result.Context;51 const QualType CanQT = Var->getType().getCanonicalType();52 53 SourceLocation AliasLoc;54 const char *AliasType = nullptr;55 if (const auto *Typedef = Result.Nodes.getNodeAs<TypedefDecl>("typedef")) {56 AliasLoc = Typedef->getLocation();57 AliasType = "typedef";58 } else if (const auto *TypeAlias =59 Result.Nodes.getNodeAs<TypeAliasDecl>("typeAlias")) {60 AliasLoc = TypeAlias->getLocation();61 AliasType = "type alias";62 } else {63 llvm_unreachable("registerMatchers has registered an unknown matcher,"64 " code out of sync");65 }66 67 diag(Var->getLocation(), "%0 declared with a const-qualified %1; "68 "results in the type being '%2' instead of '%3'")69 << Var << AliasType << CanQT.getAsString(Ctx.getPrintingPolicy())70 << guessAlternateQualification(Ctx, CanQT)71 .getAsString(Ctx.getPrintingPolicy());72 diag(AliasLoc, "%0 declared here", DiagnosticIDs::Note) << AliasType;73}74 75} // namespace clang::tidy::misc76