Author: Anonmiraj Date: 2026-10-11T16:02:33+03:00 New Revision: 6c3a6e0af0198387862e3c6da27848eca51e57e7
URL: https://github.com/llvm/llvm-project/commit/6c3a6e0af0198387862e3c6da27848eca51e57e7 DIFF: https://github.com/llvm/llvm-project/commit/6c3a6e0af0198387862e3c6da27848eca51e57e7.diff LOG: [clang] Do not compute typo-correction suggestions for disabled diagnostics (#209694) While benchmarking I noticed that Boost.MPL compiles with ~1.2% more instructions after #140629. clang spends a fair amount of time computing typo-correction suggestions for diagnostics that are never emitted, for example Boost doesn't contain any typos, so all of this work produces nothing. We can easily avoid this overhead by checking `isIgnored()` before computing suggestions, and by not treating known non-conditional directives as typos. You can see the improvement here: https://llvm-compile-time-tracker.com/compare.php?from=49de424f45389cb757c3cc8c50daf38d024e2314&to=89a68cd24f9fabf15897d7b20b77bb5b0bfb9c16&stat=instructions%3Au Added: Modified: clang/lib/Lex/PPDirectives.cpp clang/lib/Sema/SemaDeclAttr.cpp Removed: ################################################################################ diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp index 0797b1caf5954..3d991c411378e 100644 --- a/clang/lib/Lex/PPDirectives.cpp +++ b/clang/lib/Lex/PPDirectives.cpp @@ -325,8 +325,8 @@ static bool warnByDefaultOnWrongCase(StringRef Include) { /// /// \returns a similar string if exists. If no similar string exists, /// returns std::nullopt. -static std::optional<StringRef> -findSimilarStr(StringRef LHS, const std::vector<StringRef> &Candidates) { +static std::optional<StringRef> findSimilarStr(StringRef LHS, + ArrayRef<StringRef> Candidates) { // We need to check if `Candidates` has the exact case-insensitive string // because the Levenshtein distance match does not care about it. for (StringRef C : Candidates) { @@ -514,11 +514,23 @@ void Preprocessor::SuggestTypoedDirective(const Token &Tok, // directives. if (getLangOpts().AsmPreprocessor) return; - std::vector<StringRef> Candidates = { - "if", "ifdef", "ifndef", "elif", "else", "endif" - }; - if (LangOpts.C23 || LangOpts.CPlusPlus23) - Candidates.insert(Candidates.end(), {"elifdef", "elifndef"}); + // A known directive (e.g. #include or #define inside a skipped conditional + // block) is not a typo of a conditional; don't scan it. + if (getIdentifierInfo(Directive)->getPPKeywordID() != tok::pp_not_keyword) + return; + + // The scan only feeds this diagnostic; skip it when the diagnostic is + // disabled at this location (e.g. -w). + if (getDiagnostics().isIgnored(diag::warn_pp_invalid_directive, + Tok.getLocation())) + return; + + static constexpr StringRef AllCandidates[] = { + "if", "ifdef", "ifndef", "elif", "else", "endif", "elifdef", "elifndef"}; + ArrayRef<StringRef> Candidates(AllCandidates); + // #elifdef/#elifndef are only suggested in C23/C++23 and later. + if (!LangOpts.C23 && !LangOpts.CPlusPlus23) + Candidates = Candidates.drop_back(2); if (std::optional<StringRef> Sugg = findSimilarStr(Directive, Candidates)) { // Directive cannot be coming from macro. diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp index 337fe747f2d20..0361a362402bc 100644 --- a/clang/lib/Sema/SemaDeclAttr.cpp +++ b/clang/lib/Sema/SemaDeclAttr.cpp @@ -8748,6 +8748,12 @@ void Sema::checkUnusedDeclAttributes(Declarator &D) { void Sema::DiagnoseUnknownAttribute(const ParsedAttr &AL) { SourceRange NR = AL.getNormalizedRange(); + // Skip the expensive spelling-list typo-correction scan when the + // diagnostics it feeds are disabled at this location. + if (Diags.isIgnored(diag::warn_unknown_attribute_ignored, NR.getBegin()) && + Diags.isIgnored(diag::warn_unknown_attribute_ignored_suggestion, + NR.getBegin())) + return; StringRef ScopeName = AL.getNormalizedScopeName(); std::optional<StringRef> CorrectedScopeName = AL.tryGetCorrectedScopeName(ScopeName); _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
