================ @@ -0,0 +1,106 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "RedundantConstCheck.h" +#include "../utils/LexerUtils.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/ASTMatchers/ASTMatchers.h" +#include <optional> + +using namespace clang::ast_matchers; + +namespace clang::tidy::readability { + +static const internal::VariadicDynCastAllOfMatcher<Decl, VarTemplateDecl> + VarTemplateDecl; + +static std::optional<Token> +findConstToRemove(const VarDecl *VD, const MatchFinder::MatchResult &Result) { + const SourceManager &SM = *Result.SourceManager; + + const SourceLocation NameBeginLoc = VD->getQualifier() + ? VD->getQualifierLoc().getBeginLoc() + : VD->getLocation(); + + const bool IsPointer = VD->getType()->isPointerType() || + VD->getType()->isNullPtrType() || + VD->getType()->isMemberPointerType(); + + const auto ConstSearchStartLoc = [&]() -> std::optional<SourceLocation> { + if (!IsPointer) + return VD->getBeginLoc(); + + SourceLocation StarLoc = utils::lexer::findPreviousTokenKind( + NameBeginLoc, SM, Result.Context->getLangOpts(), tok::star); + + if (StarLoc.isValid()) + return StarLoc; + + // We know it is a pointer but cannot find the start token. + // This can happen when either type is aliased or `auto` was used. + // e.g: constexpr const auto const str = "hello"; + // In cases like this, clang analyzer already warns about the use of const + // as duplicate, so we can safely ignore these cases. + + return std::nullopt; + }(); + + if (!ConstSearchStartLoc || !ConstSearchStartLoc->isValid()) + return std::nullopt; + + const CharSourceRange FileRange = Lexer::makeFileCharRange( + CharSourceRange::getCharRange(*ConstSearchStartLoc, NameBeginLoc), SM, + Result.Context->getLangOpts()); + + if (!FileRange.isValid()) + return std::nullopt; + + return utils::lexer::getQualifyingToken(tok::kw_const, FileRange, + *Result.Context, SM); +} + +RedundantConstCheck::RedundantConstCheck(StringRef Name, + ClangTidyContext *Context) + : ClangTidyCheck(Name, Context) {} + +void RedundantConstCheck::registerMatchers(MatchFinder *Finder) { + Finder->addMatcher( + varDecl(isConstexpr(), unless(anyOf(hasAncestor(VarTemplateDecl()), + hasType(referenceType())))) + .bind("var_decl"), + this); +} + +void RedundantConstCheck::check(const MatchFinder::MatchResult &Result) { + const auto *VD = Result.Nodes.getNodeAs<VarDecl>("var_decl"); + + // Since we cannot tell the difference between `constexpr const` and + // `constexpr` from the AST only, if we cannot find the actual `const` token, + // we cannot do anything + const std::optional<Token> Tok = findConstToRemove(VD, Result); + if (!Tok) + return; + + const auto ConstRange = + CharSourceRange::getCharRange(Tok->getLocation(), Tok->getEndLoc()); + diag(Tok->getLocation(), + "redundant 'const' in constexpr variable declaration") + << ConstRange << FixItHint::CreateRemoval(ConstRange); +} + +bool RedundantConstCheck::isLanguageVersionSupported( + const LangOptions &LangOpts) const { + return LangOpts.CPlusPlus11; ---------------- localspook wrote:
`constexpr` variables were added to C23: ```suggestion return LangOpts.CPlusPlus11 || LangOpts.C23; ``` The line in docs saying "Requires C++11 or above." should be updated to match. https://github.com/llvm/llvm-project/pull/189733 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
