https://github.com/AnonMiraj updated https://github.com/llvm/llvm-project/pull/221605
>From fb786eda3d6b7276a822899f8612587349dc9bcc Mon Sep 17 00:00:00 2001 From: Anonmiraj <[email protected]> Date: Thu, 3 Sep 2026 07:29:27 +0300 Subject: [PATCH 1/4] Reland "[clang] Don't add documentation comments to the AST if not requested (#206363)" This reverts commit 26fc63e1ab6d05bdf708e5311e683f158a7204bd, restoring e046dce4a4c80610b49d67bc02c85f86b1a6353d unchanged. The original was reverted for a compile-time regression: +7.6% instructions at -O0 and +2.8% at -O3 on the compile-time tracker geomean, up to +14.9% on individual benchmarks. The next commit fixes that; this one is a verbatim reland so the delta is reviewable on its own. Don't collect documentation comments unless they are requested (-Wdocumentation, -fparse-all-comments, code completion, PCH serialization, or libclang) closes #165515 --------- Co-authored-by: Erich Keane <[email protected]> --- .../clang-doc/tool/ClangDocMain.cpp | 3 +- clang-tools-extra/clangd/Compiler.cpp | 3 +- .../clangd/index/IndexAction.cpp | 3 +- clang/docs/ReleaseNotes.md | 6 + clang/include/clang/Basic/CommentOptions.h | 8 + clang/include/clang/Basic/Diagnostic.h | 10 + clang/include/clang/Basic/DiagnosticIDs.h | 6 + clang/include/clang/Basic/LangOptions.def | 2 - clang/include/clang/Options/Options.td | 8 +- clang/include/clang/Sema/Sema.h | 5 + clang/lib/AST/ASTContext.cpp | 2 +- clang/lib/Basic/DiagnosticIDs.cpp | 196 ++++++++++-------- clang/lib/Driver/ToolChains/Clang.cpp | 2 + clang/lib/ExtractAPI/ExtractAPIConsumer.cpp | 3 + clang/lib/Frontend/ASTUnit.cpp | 6 + clang/lib/Frontend/CompilerInvocation.cpp | 1 + clang/lib/Frontend/FrontendActions.cpp | 6 + clang/lib/Sema/Sema.cpp | 33 ++- clang/lib/Sema/SemaDecl.cpp | 7 +- clang/test/AST/ast-dump-comment-retention.cpp | 28 +++ .../warn-documentation-comment-retention.cpp | 38 ++++ 21 files changed, 278 insertions(+), 98 deletions(-) create mode 100644 clang/test/AST/ast-dump-comment-retention.cpp create mode 100644 clang/test/Sema/warn-documentation-comment-retention.cpp diff --git a/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp b/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp index 00290d7cdc74b..0b81a3cb20351 100644 --- a/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp +++ b/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp @@ -285,7 +285,8 @@ Example usage for a project using a compile commands database: llvm::outs() << "Emiting docs in " << Format << " format.\n"; auto G = ExitOnErr(doc::findGeneratorByName(Format)); - ArgumentsAdjuster ArgAdjuster; + ArgumentsAdjuster ArgAdjuster = getInsertArgumentAdjuster( + "-fretain-comments", tooling::ArgumentInsertPosition::END); if (!DoxygenOnly) ArgAdjuster = combineAdjusters( getInsertArgumentAdjuster("-fparse-all-comments", diff --git a/clang-tools-extra/clangd/Compiler.cpp b/clang-tools-extra/clangd/Compiler.cpp index 4644cd75c0833..aaeaab30b96db 100644 --- a/clang-tools-extra/clangd/Compiler.cpp +++ b/clang-tools-extra/clangd/Compiler.cpp @@ -121,7 +121,8 @@ buildCompilerInvocation(const ParseInputs &Inputs, clang::DiagnosticConsumer &D, // createInvocationFromCommandLine sets DisableFree. CI->getFrontendOpts().DisableFree = false; CI->getLangOpts().CommentOpts.ParseAllComments = true; - CI->getLangOpts().RetainCommentsFromSystemHeaders = true; + CI->getLangOpts().CommentOpts.RetainComments = true; + CI->getLangOpts().CommentOpts.RetainCommentsFromSystemHeaders = true; disableUnsupportedOptions(*CI); return CI; diff --git a/clang-tools-extra/clangd/index/IndexAction.cpp b/clang-tools-extra/clangd/index/IndexAction.cpp index 489c61f1ff424..21e055b82d722 100644 --- a/clang-tools-extra/clangd/index/IndexAction.cpp +++ b/clang-tools-extra/clangd/index/IndexAction.cpp @@ -167,7 +167,8 @@ class IndexAction : public ASTFrontendAction { bool BeginInvocation(CompilerInstance &CI) override { // We want all comments, not just the doxygen ones. CI.getLangOpts().CommentOpts.ParseAllComments = true; - CI.getLangOpts().RetainCommentsFromSystemHeaders = true; + CI.getLangOpts().CommentOpts.RetainComments = true; + CI.getLangOpts().CommentOpts.RetainCommentsFromSystemHeaders = true; // Index the whole file even if there are warnings and -Werror is set. // Avoids some analyses too. Set in two places as we're late to the party. CI.getDiagnosticOpts().IgnoreWarnings = true; diff --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md index bf295981710ac..9142fcddb363a 100644 --- a/clang/docs/ReleaseNotes.md +++ b/clang/docs/ReleaseNotes.md @@ -433,6 +433,12 @@ features cannot lower the translation-unit ABI level; - Improved how Unicode characters are displayed in diagnostic messages. +- Clang no longer retains source comments in the AST when nothing will read them + back. Comments are now collected only when they may be consumed (e.g. with + ``-fparse-all-comments``, when ``-Wdocumentation`` is enabled, when emitting a + PCH/module, or during code completion), reducing memory overhead for typical + compilations. + - `-Wtautological-pointer-compare` and `-Wpointer-bool-conversion` now diagnose a reference to a function (e.g. of type `void (&)()`) compared against or converted to a null pointer, the same as a bare function name. diff --git a/clang/include/clang/Basic/CommentOptions.h b/clang/include/clang/Basic/CommentOptions.h index 7d142fc32f511..73e7cba91cca8 100644 --- a/clang/include/clang/Basic/CommentOptions.h +++ b/clang/include/clang/Basic/CommentOptions.h @@ -30,6 +30,14 @@ struct CommentOptions { /// Treat ordinary comments as documentation comments. bool ParseAllComments = false; + /// Force the front end to retain all documentation comments in the AST, even + /// when no comment consuming diagnostic or language option is enabled. Tools + /// that query comments after parsing set this. + bool RetainComments = false; + + /// Retain documentation comments from system headers in the AST. + bool RetainCommentsFromSystemHeaders = false; + CommentOptions() = default; }; diff --git a/clang/include/clang/Basic/Diagnostic.h b/clang/include/clang/Basic/Diagnostic.h index 834f026aff62d..699cd89791619 100644 --- a/clang/include/clang/Basic/Diagnostic.h +++ b/clang/include/clang/Basic/Diagnostic.h @@ -974,6 +974,16 @@ class DiagnosticsEngine : public RefCountedBase<DiagnosticsEngine> { diag::Severity::Ignored; } + bool areAllIgnored(StringRef Group, SourceLocation Loc) const { + llvm::SmallVector<diag::kind> diagsInGroup; + bool Failed = Diags->getDiagnosticsInGroup(diag::Flavor::WarningOrError, + Group, diagsInGroup); + assert(!Failed && "Incorrect group name?"); + (void)Failed; + return Diags->getDiagnosticListHighestSeverity(diagsInGroup, Loc, *this) == + diag::Severity::Ignored; + } + /// Based on the way the client configured the DiagnosticsEngine /// object, classify the specified diagnostic ID into a Level, consumable by /// the DiagnosticConsumer. diff --git a/clang/include/clang/Basic/DiagnosticIDs.h b/clang/include/clang/Basic/DiagnosticIDs.h index 148d772a9e593..1bb0529c3ff26 100644 --- a/clang/include/clang/Basic/DiagnosticIDs.h +++ b/clang/include/clang/Basic/DiagnosticIDs.h @@ -516,6 +516,12 @@ class DiagnosticIDs : public RefCountedBase<DiagnosticIDs> { getDiagnosticSeverity(unsigned DiagID, SourceLocation Loc, const DiagnosticsEngine &Diag) const LLVM_READONLY; + /// Given a collection of diagnostic IDs, get the 'highest' severity of them + /// at the provided location for this DiagnosticsEngine. + diag::Severity getDiagnosticListHighestSeverity( + llvm::ArrayRef<diag::kind> DiagIDs, SourceLocation Loc, + const DiagnosticsEngine &Diag) const LLVM_READONLY; + Class getDiagClass(unsigned DiagID) const; /// Whether the diagnostic may leave the AST in a state where some diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def index ad993ce7e5d95..1422125b77741 100644 --- a/clang/include/clang/Basic/LangOptions.def +++ b/clang/include/clang/Basic/LangOptions.def @@ -405,8 +405,6 @@ LANGOPT(ApplePragmaPack, 1, 0, NotCompatible, "Apple gcc-compatible #pragma pack LANGOPT(XLPragmaPack, 1, 0, NotCompatible, "IBM XL #pragma pack handling") -LANGOPT(RetainCommentsFromSystemHeaders, 1, 0, Compatible, "retain documentation comments from system headers in the AST") - LANGOPT(APINotes, 1, 0, NotCompatible, "use external API notes") LANGOPT(APINotesModules, 1, 0, NotCompatible, "use module-based external API notes") LANGOPT(SwiftVersionIndependentAPINotes, 1, 0, NotCompatible, "use external API notes capturing all versions") diff --git a/clang/include/clang/Options/Options.td b/clang/include/clang/Options/Options.td index 9ef012dfe1d03..f97a2a54e665d 100644 --- a/clang/include/clang/Options/Options.td +++ b/clang/include/clang/Options/Options.td @@ -2221,6 +2221,12 @@ defm define_target_os_macros : OptInCC1FFlag<"define-target-os-macros", def fparse_all_comments : Flag<["-"], "fparse-all-comments">, Group<f_clang_Group>, Visibility<[ClangOption, CC1Option]>, MarshallingInfoFlag<LangOpts<"CommentOpts.ParseAllComments">>; +def fretain_comments : Flag<["-"], "fretain-comments">, Group<f_clang_Group>, + Visibility<[ClangOption, CC1Option]>, + HelpText<"Retain documentation comments in the AST even when no diagnostic or " + "language option would otherwise require them (e.g. for tools that " + "query comments after parsing)">, + MarshallingInfoFlag<LangOpts<"CommentOpts.RetainComments">>; def frecord_command_line : Flag<["-"], "frecord-command-line">, DocBrief<[{Generate a section named ".GCC.command.line" containing the driver command-line. After linking, the section may contain multiple command @@ -3942,7 +3948,7 @@ defm implicit_modules : BoolFOption<"implicit-modules", [NoXarchOption], [ClangOption, CLOption]>>; def fretain_comments_from_system_headers : Flag<["-"], "fretain-comments-from-system-headers">, Group<f_Group>, Visibility<[ClangOption, CC1Option]>, - MarshallingInfoFlag<LangOpts<"RetainCommentsFromSystemHeaders">>; + MarshallingInfoFlag<LangOpts<"CommentOpts.RetainCommentsFromSystemHeaders">>; def fmodule_header : Flag <["-"], "fmodule-header">, Group<f_Group>, Visibility<[ClangOption, CLOption]>, HelpText<"Build a C++20 Header Unit from a header">; diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h index 9b07b591b8c07..36fc50dcd426b 100644 --- a/clang/include/clang/Sema/Sema.h +++ b/clang/include/clang/Sema/Sema.h @@ -1126,6 +1126,11 @@ class Sema final : public SemaBase { void ActOnComment(SourceRange Comment); + /// Returns true if a comment at \p Loc should be retained in the AST + /// (some consumer such as -Wdocumentation, -fparse-all-comments, code + /// completion, or AST-file serialization may read it back). + bool shouldRetainCommentsInAST(SourceLocation Loc) const; + /// Retrieve the parser's current scope. /// /// This routine must only be used when it is certain that semantic analysis diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp index b7e771595e86e..cf1c68d0d4443 100644 --- a/clang/lib/AST/ASTContext.cpp +++ b/clang/lib/AST/ASTContext.cpp @@ -357,7 +357,7 @@ RawComment *ASTContext::getRawCommentNoCache(RawCommentLookupKey Key) const { } void ASTContext::addComment(const RawComment &RC) { - assert(LangOpts.RetainCommentsFromSystemHeaders || + assert(LangOpts.CommentOpts.RetainCommentsFromSystemHeaders || !SourceMgr.isInSystemHeader(RC.getSourceRange().getBegin())); Comments.addComment(RC, LangOpts.CommentOpts, BumpAlloc); } diff --git a/clang/lib/Basic/DiagnosticIDs.cpp b/clang/lib/Basic/DiagnosticIDs.cpp index 3709528e497d2..ef9db935ca752 100644 --- a/clang/lib/Basic/DiagnosticIDs.cpp +++ b/clang/lib/Basic/DiagnosticIDs.cpp @@ -541,103 +541,131 @@ DiagnosticIDs::getDiagnosticLevel(unsigned DiagID, SourceLocation Loc, diag::Severity DiagnosticIDs::getDiagnosticSeverity(unsigned DiagID, SourceLocation Loc, const DiagnosticsEngine &Diag) const { - bool IsCustomDiag = DiagnosticIDs::IsCustomDiag(DiagID); - assert(getDiagClass(DiagID) != CLASS_NOTE); - - // Specific non-error diagnostics may be mapped to various levels from ignored - // to error. Errors can only be mapped to fatal. - diag::Severity Result = diag::Severity::Fatal; + return getDiagnosticListHighestSeverity({DiagID}, Loc, Diag); +} - // Get the mapping information, or compute it lazily. +diag::Severity DiagnosticIDs::getDiagnosticListHighestSeverity( + llvm::ArrayRef<diag::kind> DiagIDs, SourceLocation Loc, + const DiagnosticsEngine &Diag) const { DiagnosticsEngine::DiagState *State = Diag.GetDiagStateForLoc(Loc); - DiagnosticMapping Mapping = State->getOrAddMapping((diag::kind)DiagID); - - // TODO: Can a null severity really get here? - if (Mapping.getSeverity() != diag::Severity()) - Result = Mapping.getSeverity(); - - // Upgrade ignored diagnostics if -Weverything is enabled. - if (State->EnableAllWarnings && Result == diag::Severity::Ignored && - !Mapping.isUser() && - (IsCustomDiag || getDiagClass(DiagID) != CLASS_REMARK)) - Result = diag::Severity::Warning; - - // Ignore -pedantic diagnostics inside __extension__ blocks. - // (The diagnostics controlled by -pedantic are the extension diagnostics - // that are not enabled by default.) - bool EnabledByDefault = false; - bool IsExtensionDiag = isExtensionDiag(DiagID, EnabledByDefault); - if (Diag.AllExtensionsSilenced && IsExtensionDiag && !EnabledByDefault) - return diag::Severity::Ignored; - - // For extension diagnostics that haven't been explicitly mapped, check if we - // should upgrade the diagnostic. Skip if the user explicitly suppressed it - // (e.g. -Wno-foo). - if (IsExtensionDiag && - !(Mapping.isUser() && Result == diag::Severity::Ignored)) { - if (Mapping.hasNoWarningAsError()) - Result = std::max(Result, - std::min(State->ExtBehavior, diag::Severity::Warning)); - else - Result = std::max(Result, State->ExtBehavior); - } - - // At this point, ignored errors can no longer be upgraded. - if (Result == diag::Severity::Ignored) - return Result; - // Honor -w: this disables all messages which are not Error/Fatal by - // default (disregarding attempts to upgrade severity from Warning to Error), - // as well as disabling all messages which are currently mapped to Warning - // (whether by default or downgraded from Error via e.g. -Wno-error or #pragma - // diagnostic.) - // FIXME: Should -w be ignored for custom warnings without a group? - if (State->IgnoreAllWarnings) { - if ((!IsCustomDiag || CustomDiagInfo->getDescription(DiagID).GetGroup()) && - (Result == diag::Severity::Warning || - (Result >= diag::Severity::Error && - !isDefaultMappingAsError((diag::kind)DiagID)))) + auto checkSingleDiag = [&](diag::kind DiagID) -> diag::Severity { + bool IsCustomDiag = DiagnosticIDs::IsCustomDiag(DiagID); + assert(getDiagClass(DiagID) != CLASS_NOTE); + + // Specific non-error diagnostics may be mapped to various levels from + // ignored to error. Errors can only be mapped to fatal. + diag::Severity Result = diag::Severity::Fatal; + + // Get the mapping information, or compute it lazily. + DiagnosticMapping Mapping = State->getOrAddMapping((diag::kind)DiagID); + + // TODO: Can a null severity really get here? + if (Mapping.getSeverity() != diag::Severity()) + Result = Mapping.getSeverity(); + + // Upgrade ignored diagnostics if -Weverything is enabled. + if (State->EnableAllWarnings && Result == diag::Severity::Ignored && + !Mapping.isUser() && + (IsCustomDiag || getDiagClass(DiagID) != CLASS_REMARK)) + Result = diag::Severity::Warning; + + // Ignore -pedantic diagnostics inside __extension__ blocks. + // (The diagnostics controlled by -pedantic are the extension diagnostics + // that are not enabled by default.) + bool EnabledByDefault = false; + bool IsExtensionDiag = isExtensionDiag(DiagID, EnabledByDefault); + if (Diag.AllExtensionsSilenced && IsExtensionDiag && !EnabledByDefault) return diag::Severity::Ignored; - } - // If -Werror is enabled, map warnings to errors unless explicitly disabled. - if (Result == diag::Severity::Warning) { - if (State->WarningsAsErrors && !Mapping.hasNoWarningAsError()) + // For extension diagnostics that haven't been explicitly mapped, check if + // we should upgrade the diagnostic. Skip if the user explicitly + // suppressed it (e.g. -Wno-foo). + if (IsExtensionDiag && + !(Mapping.isUser() && Result == diag::Severity::Ignored)) { + if (Mapping.hasNoWarningAsError()) + Result = std::max( + Result, std::min(State->ExtBehavior, diag::Severity::Warning)); + else + Result = std::max(Result, State->ExtBehavior); + } + + // At this point, ignored errors can no longer be upgraded. + if (Result == diag::Severity::Ignored) + return Result; + + // Honor -w: this disables all messages which are not Error/Fatal by + // default (disregarding attempts to upgrade severity from Warning to + // Error), as well as disabling all messages which are currently mapped to + // Warning (whether by default or downgraded from Error via e.g. + // -Wno-error or #pragma diagnostic.) + // FIXME: Should -w be ignored for custom warnings without a group? + if (State->IgnoreAllWarnings) { + if ((!IsCustomDiag || + CustomDiagInfo->getDescription(DiagID).GetGroup()) && + (Result == diag::Severity::Warning || + (Result >= diag::Severity::Error && + !isDefaultMappingAsError((diag::kind)DiagID)))) + return diag::Severity::Ignored; + } + + // If -Werror is enabled, map warnings to errors unless explicitly + // disabled. + if (Result == diag::Severity::Warning) { + if (State->WarningsAsErrors && !Mapping.hasNoWarningAsError()) + Result = diag::Severity::Error; + } + + // If -Wfatal-errors is enabled, map errors to fatal unless explicitly + // disabled. + if (Result == diag::Severity::Error) { + if (State->ErrorsAsFatal && !Mapping.hasNoErrorAsFatal()) + Result = diag::Severity::Fatal; + } + + // If explicitly requested, map fatal errors to errors. + if (Result == diag::Severity::Fatal && + DiagID != diag::fatal_too_many_errors && Diag.FatalsAsError) Result = diag::Severity::Error; - } - // If -Wfatal-errors is enabled, map errors to fatal unless explicitly - // disabled. - if (Result == diag::Severity::Error) { - if (State->ErrorsAsFatal && !Mapping.hasNoErrorAsFatal()) - Result = diag::Severity::Fatal; - } + // Rest of the mappings are only applicable for diagnostics associated + // with a SourceLocation, bail out early for others. + if (!Diag.hasSourceManager()) + return Result; + + // We check both the location-specific state and the ForceSystemWarnings + // override. In some cases (like template instantiations from system + // modules), the location-specific state might have suppression enabled, + // but the engine might have an override (e.g. + // AllowWarningInSystemHeaders) to show the warning. + if (State->SuppressSystemWarnings && !Diag.getForceSystemWarnings() && + shouldSuppressAsSystemWarning(DiagID, Loc, Diag)) { + return diag::Severity::Ignored; + } - // If explicitly requested, map fatal errors to errors. - if (Result == diag::Severity::Fatal && - DiagID != diag::fatal_too_many_errors && Diag.FatalsAsError) - Result = diag::Severity::Error; + // Clang-diagnostics pragmas always take precedence over suppression + // mapping. + if (!Mapping.isPragma() && Diag.isSuppressedViaMapping(DiagID, Loc)) + return diag::Severity::Ignored; - // Rest of the mappings are only applicable for diagnostics associated with a - // SourceLocation, bail out early for others. - if (!Diag.hasSourceManager()) return Result; + }; - // We check both the location-specific state and the ForceSystemWarnings - // override. In some cases (like template instantiations from system modules), - // the location-specific state might have suppression enabled, but the - // engine might have an override (e.g. AllowWarningInSystemHeaders) to show - // the warning. - if (State->SuppressSystemWarnings && !Diag.getForceSystemWarnings() && - shouldSuppressAsSystemWarning(DiagID, Loc, Diag)) { - return diag::Severity::Ignored; + diag::Severity CompositeResult = diag::Severity::Ignored; + for (diag::kind DiagID : DiagIDs) { + CompositeResult = std::max(CompositeResult, checkSingleDiag(DiagID)); + + // If we already hit 'fatal', we can't get any higher! So just return that. + // We could potentially short-cut this by taking a parameter for "return + // first greater than", but since our uses of this are fairly small, and + // that only optimizes for the "we are about to do something expensive + // anyway" variant (that is, when everything is NOT ignored), it doesn't + // seem particularly valuable. + if (CompositeResult == diag::Severity::Fatal) + break; } - // Clang-diagnostics pragmas always take precedence over suppression mapping. - if (!Mapping.isPragma() && Diag.isSuppressedViaMapping(DiagID, Loc)) - return diag::Severity::Ignored; - - return Result; + return CompositeResult; } bool DiagnosticIDs::shouldSuppressAsSystemWarning( diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index b3923c0c1e981..26978796a7e80 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -8165,6 +8165,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, Args.AddAllArgs(CmdArgs, options::OPT_fcomment_block_commands); // Forward -fparse-all-comments to -cc1. Args.AddAllArgs(CmdArgs, options::OPT_fparse_all_comments); + // Forward -fretain-comments to -cc1. + Args.AddAllArgs(CmdArgs, options::OPT_fretain_comments); // Turn -fplugin=name.so into -load name.so for (const Arg *A : Args.filtered(options::OPT_fplugin_EQ)) { diff --git a/clang/lib/ExtractAPI/ExtractAPIConsumer.cpp b/clang/lib/ExtractAPI/ExtractAPIConsumer.cpp index c81d76764643b..4e3c5466e577f 100644 --- a/clang/lib/ExtractAPI/ExtractAPIConsumer.cpp +++ b/clang/lib/ExtractAPI/ExtractAPIConsumer.cpp @@ -455,6 +455,9 @@ ExtractAPIAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) { } bool ExtractAPIAction::PrepareToExecuteAction(CompilerInstance &CI) { + // ExtractAPI reads documentation comments off the AST. + CI.getLangOpts().CommentOpts.RetainComments = true; + // Public API can never be inside function bodies, so skip parsing them. CI.getFrontendOpts().SkipFunctionBodies = true; diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp index 75e4f7772f47c..738fe99cef46b 100644 --- a/clang/lib/Frontend/ASTUnit.cpp +++ b/clang/lib/Frontend/ASTUnit.cpp @@ -1533,6 +1533,9 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction( // We'll manage file buffers ourselves. CI->getPreprocessorOpts().RetainRemappedFileBuffers = true; + // libclang and other ASTUnit clients query documentation comments after + // parsing, so keep them in the AST. + CI->getLangOpts().CommentOpts.RetainComments = true; CI->getFrontendOpts().DisableFree = false; ProcessWarningOptions(AST->getDiagnostics(), CI->getDiagnosticOpts(), AST->getFileManager().getVirtualFileSystem()); @@ -1641,6 +1644,9 @@ bool ASTUnit::LoadFromCompilerInvocation( // We'll manage file buffers ourselves. Invocation->getPreprocessorOpts().RetainRemappedFileBuffers = true; + // libclang and other ASTUnit clients query documentation comments after + // parsing, so keep them in the AST. + Invocation->getLangOpts().CommentOpts.RetainComments = true; Invocation->getFrontendOpts().DisableFree = false; getDiagnostics().Reset(); ProcessWarningOptions(getDiagnostics(), Invocation->getDiagnosticOpts(), diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index ea8368908879a..a09976f0d441c 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -5298,6 +5298,7 @@ std::string CompilerInvocation::computeContextHash() const { HBuilder.add(getLangOpts().ObjCRuntime); HBuilder.addRange(getLangOpts().CommentOpts.BlockCommandNames); + HBuilder.add(getLangOpts().CommentOpts.RetainCommentsFromSystemHeaders); // Extend the signature with the target options. HBuilder.add(getTargetOpts().Triple, getTargetOpts().CPU, diff --git a/clang/lib/Frontend/FrontendActions.cpp b/clang/lib/Frontend/FrontendActions.cpp index e7b05740b8376..aaaf0b6401502 100644 --- a/clang/lib/Frontend/FrontendActions.cpp +++ b/clang/lib/Frontend/FrontendActions.cpp @@ -86,6 +86,8 @@ ASTPrintAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) { std::unique_ptr<ASTConsumer> ASTDumpAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) { + // Dumping the AST shows documentation comments. + CI.getLangOpts().CommentOpts.RetainComments = true; const FrontendOptions &Opts = CI.getFrontendOpts(); return CreateASTDumper(nullptr /*Dump to stdout.*/, Opts.ASTDumpFilter, Opts.ASTDumpDecls, Opts.ASTDumpAll, @@ -250,6 +252,10 @@ GenerateModuleFromModuleMapAction::CreateOutputFile(CompilerInstance &CI, bool GenerateModuleInterfaceAction::PrepareToExecuteAction( CompilerInstance &CI) { + // Documentation comments must still be serialized into the BMI + // so importers can query them. + CI.getLangOpts().CommentOpts.RetainComments = true; + for (const auto &FIF : CI.getFrontendOpts().Inputs) { if (const auto InputFormat = FIF.getKind().getFormat(); InputFormat != InputKind::Format::Source) { diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp index 21f71d7f8b40e..f933444c22adf 100644 --- a/clang/lib/Sema/Sema.cpp +++ b/clang/lib/Sema/Sema.cpp @@ -2749,10 +2749,39 @@ LambdaScopeInfo *Sema::getCurGenericLambda() { return nullptr; } +bool Sema::shouldRetainCommentsInAST(SourceLocation Loc) const { + if (!LangOpts.CommentOpts.RetainCommentsFromSystemHeaders && + SourceMgr.isInSystemHeader(Loc)) + return false; + + if (LangOpts.CommentOpts.ParseAllComments) + return true; + + if (LangOpts.CommentOpts.RetainComments) + return true; + + // When building a PCH the comments are serialized into the AST file + // so downstream consumers like clangd) can retrieve documentation, and the + // incremental/REPL front end may query them interactively. + if (TUKind != TU_Complete) + return true; + + if (PP.isCodeCompletionEnabled()) + return true; + + // Keep the comment if any of the -Wdocumentation warnings is enabled at + // its location (checking the location handles warnings turned on by + // `#pragma clang diagnostic`). -Wdocumentation-pedantic is checked + // separately because it is not a subgroup of -Wdocumentation. + if (!Diags.areAllIgnored("documentation", Loc) || + !Diags.areAllIgnored("documentation-pedantic", Loc)) + return true; + + return false; +} void Sema::ActOnComment(SourceRange Comment) { - if (!LangOpts.RetainCommentsFromSystemHeaders && - SourceMgr.isInSystemHeader(Comment.getBegin())) + if (!shouldRetainCommentsInAST(Comment.getBegin())) return; RawComment RC(SourceMgr, Comment, LangOpts.CommentOpts, false); if (RC.isAlmostTrailingComment() || RC.hasUnsupportedSplice(SourceMgr)) { diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp index d6114ccbae7fe..8c29b30d7a8ac 100644 --- a/clang/lib/Sema/SemaDecl.cpp +++ b/clang/lib/Sema/SemaDecl.cpp @@ -30,7 +30,6 @@ #include "clang/AST/StmtCXX.h" #include "clang/AST/Type.h" #include "clang/Basic/Builtins.h" -#include "clang/Basic/DiagnosticComment.h" #include "clang/Basic/HLSLRuntime.h" #include "clang/Basic/PartialDiagnostic.h" #include "clang/Basic/SourceManager.h" @@ -15731,10 +15730,8 @@ void Sema::ActOnDocumentableDecls(ArrayRef<Decl *> Group) { if (Group.empty() || !Group[0]) return; - if (Diags.isIgnored(diag::warn_doc_param_not_found, - Group[0]->getLocation()) && - Diags.isIgnored(diag::warn_unknown_comment_command_name, - Group[0]->getLocation())) + if (Diags.areAllIgnored("documentation", Group[0]->getLocation()) && + Diags.areAllIgnored("documentation-pedantic", Group[0]->getLocation())) return; if (Group.size() >= 2) { diff --git a/clang/test/AST/ast-dump-comment-retention.cpp b/clang/test/AST/ast-dump-comment-retention.cpp new file mode 100644 index 0000000000000..e2a68e2f3221d --- /dev/null +++ b/clang/test/AST/ast-dump-comment-retention.cpp @@ -0,0 +1,28 @@ +// Comments are only collected into the AST when a consumer may read them back +// (see Sema::shouldRetainCommentsInAST). -ast-dump is such a consumer: it +// force-enables comment retention, so documentation comments remain visible in +// its output even without -Wdocumentation. An ordinary comment is only turned +// into an AST comment node when -fparse-all-comments is passed. + +// RUN: %clang_cc1 -ast-dump -ast-dump-filter Test %s \ +// RUN: | FileCheck -strict-whitespace %s --check-prefixes=CHECK,DEFAULT +// RUN: %clang_cc1 -fparse-all-comments -ast-dump -ast-dump-filter Test %s \ +// RUN: | FileCheck -strict-whitespace %s --check-prefixes=CHECK,ALL + +/// Doc +int Test_DocComment; +// A documentation comment is retained for -ast-dump in both modes. +// CHECK: VarDecl{{.*}}Test_DocComment +// CHECK-NEXT: FullComment +// CHECK-NEXT: ParagraphComment +// CHECK-NEXT: TextComment{{.*}} Text=" Doc" + +// Ordinary +int Test_OrdinaryComment; +// An ordinary comment becomes an AST comment node only with +// -fparse-all-comments; by default it is dropped. +// CHECK: VarDecl{{.*}}Test_OrdinaryComment +// ALL-NEXT: FullComment +// ALL-NEXT: ParagraphComment +// ALL-NEXT: TextComment{{.*}} Text=" Ordinary" +// DEFAULT-NOT: FullComment diff --git a/clang/test/Sema/warn-documentation-comment-retention.cpp b/clang/test/Sema/warn-documentation-comment-retention.cpp new file mode 100644 index 0000000000000..5d7a50b0bb970 --- /dev/null +++ b/clang/test/Sema/warn-documentation-comment-retention.cpp @@ -0,0 +1,38 @@ +// RUN: %clang_cc1 -fsyntax-only -verify %s + +// The comment-retention optimization (Sema::shouldRetainCommentsInAST) must +// still parse a documentation comment when -Wdocumentation is enabled at the +// comment's location -- including when it is turned on by a #pragma clang +// diagnostic rather than on the command line. The check is done at the +// comment's location precisely so pragma regions are honored. + +/// \returns Aaa +void outside(); +// -Wdocumentation is off at this location, so the comment is not checked and +// no diagnostic is produced. -verify fails on any unexpected diagnostic, so +// this line asserts the comment is *not* diagnosed here. + +#pragma clang diagnostic push +#pragma clang diagnostic warning "-Wdocumentation" +/// \returns Aaa +void inside(); +// expected-warning@-2 {{'\returns' command used in a comment that is attached to a function returning void}} +#pragma clang diagnostic pop + +// Any warning in the -Wdocumentation group must keep the comment, not just a +// hard-coded subset: -Wdocumentation-html is a subgroup of -Wdocumentation. +#pragma clang diagnostic push +#pragma clang diagnostic warning "-Wdocumentation-html" +/// Aaa <br></br> +void html_inside(); +// expected-warning@-2 {{HTML end tag 'br' is forbidden}} +#pragma clang diagnostic pop + +// -Wdocumentation-unknown-command is under -Wdocumentation-pedantic, which is +// not a subgroup of -Wdocumentation and must be checked separately. +#pragma clang diagnostic push +#pragma clang diagnostic warning "-Wdocumentation-unknown-command" +/// \unknowncommand Aaa +void unknown_inside(); +// expected-warning@-2 {{unknown command tag name}} +#pragma clang diagnostic pop >From 1f1eb5f99dcb69f4c0eec129b7a6415dbab26602 Mon Sep 17 00:00:00 2001 From: Anonmiraj <[email protected]> Date: Sat, 5 Sep 2026 09:15:58 +0300 Subject: [PATCH 2/4] [clang][NFC] Share the ForceSystemWarnings RAII and the system classification --- clang/include/clang/Basic/Diagnostic.h | 23 +++++++++++++++++++++++ clang/lib/Basic/Diagnostic.cpp | 7 +++++++ clang/lib/Sema/AnalysisBasedWarnings.cpp | 4 +--- clang/lib/Sema/SemaAvailability.cpp | 16 ++-------------- 4 files changed, 33 insertions(+), 17 deletions(-) diff --git a/clang/include/clang/Basic/Diagnostic.h b/clang/include/clang/Basic/Diagnostic.h index 699cd89791619..2d3f48f602bed 100644 --- a/clang/include/clang/Basic/Diagnostic.h +++ b/clang/include/clang/Basic/Diagnostic.h @@ -589,6 +589,12 @@ class DiagnosticsEngine : public RefCountedBase<DiagnosticsEngine> { return GetDiagStateForLoc(Loc); } + /// Returns whether \p Loc is in a system header and/or a system macro, as a + /// value in [0, 4). Severity depends on this through + /// DiagnosticIDs::shouldSuppressAsSystemWarning(), so a cache keyed on + /// getDiagStateKeyForLoc() must take it into account as well. + unsigned getDiagStateSystemClassForLoc(SourceLocation Loc) const; + /// True if an active diagnostic suppression mapping makes severity dependent /// on the file path. bool hasDiagSuppressionMapping() const { @@ -1150,6 +1156,23 @@ class IgnoreAllWarningDiagRAII { ~IgnoreAllWarningDiagRAII() { Diag.setIgnoreAllWarnings(OldValue); } }; +/// RAII class that temporarily forces warnings in system headers and system +/// macros to be shown on a DiagnosticsEngine and restores the previous state on +/// destruction. Use it to ask what a diagnostic's severity would be if the +/// location were not in a system header. +class ForceSystemWarningsRAII { + DiagnosticsEngine &Diag; + bool OldValue; + +public: + explicit ForceSystemWarningsRAII(DiagnosticsEngine &Diag, bool Force = true) + : Diag(Diag), OldValue(Diag.getForceSystemWarnings()) { + if (Force) + Diag.setForceSystemWarnings(true); + } + ~ForceSystemWarningsRAII() { Diag.setForceSystemWarnings(OldValue); } +}; + /// The streaming interface shared between DiagnosticBuilder and /// PartialDiagnostic. This class is not intended to be constructed directly /// but only as base class of DiagnosticBuilder and PartialDiagnostic builder. diff --git a/clang/lib/Basic/Diagnostic.cpp b/clang/lib/Basic/Diagnostic.cpp index 48dd9559ab8e6..995fd6dff2254 100644 --- a/clang/lib/Basic/Diagnostic.cpp +++ b/clang/lib/Basic/Diagnostic.cpp @@ -596,6 +596,13 @@ bool WarningsSpecialCaseList::isDiagSuppressed(diag::kind DiagId, return LastSup > LastEmit; } +unsigned +DiagnosticsEngine::getDiagStateSystemClassForLoc(SourceLocation Loc) const { + const SourceManager &SM = getSourceManager(); + return (SM.isInSystemHeader(SM.getExpansionLoc(Loc)) ? 2u : 0u) | + (SM.isInSystemMacro(Loc) ? 1u : 0u); +} + bool DiagnosticsEngine::isSuppressedViaMapping(diag::kind DiagId, SourceLocation DiagLoc) const { if (!hasSourceManager() || !DiagSuppressionMapping) diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp index d0500a6defd64..fb7ead718a4ac 100644 --- a/clang/lib/Sema/AnalysisBasedWarnings.cpp +++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp @@ -2802,9 +2802,7 @@ sema::AnalysisBasedWarnings::getPolicyInEffectAt(SourceLocation Loc) { unsigned SysIdx = 0; if (Cacheable) { StateKey = D.getDiagStateKeyForLoc(Loc); - const SourceManager &SM = D.getSourceManager(); - SysIdx = (SM.isInSystemHeader(SM.getExpansionLoc(Loc)) ? 2u : 0u) | - (SM.isInSystemMacro(Loc) ? 1u : 0u); + SysIdx = D.getDiagStateSystemClassForLoc(Loc); auto It = PolicyCache[SysIdx].find(StateKey); if (It != PolicyCache[SysIdx].end()) { Policy P = It->second; diff --git a/clang/lib/Sema/SemaAvailability.cpp b/clang/lib/Sema/SemaAvailability.cpp index 636168d13d5b8..25f0cb5f1af8f 100644 --- a/clang/lib/Sema/SemaAvailability.cpp +++ b/clang/lib/Sema/SemaAvailability.cpp @@ -669,20 +669,8 @@ static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K, bool ShouldAllowWarningInSystemHeader = InstantiationLoc != Loc && !S.getSourceManager().isInSystemHeader(InstantiationLoc); - struct AllowWarningInSystemHeaders { - AllowWarningInSystemHeaders(DiagnosticsEngine &E, - bool AllowWarningInSystemHeaders) - : Engine(E), Prev(E.getForceSystemWarnings()) { - if (AllowWarningInSystemHeaders) - Engine.setForceSystemWarnings(true); - } - ~AllowWarningInSystemHeaders() { Engine.setForceSystemWarnings(Prev); } - - private: - DiagnosticsEngine &Engine; - bool Prev; - } SystemWarningOverrideRAII(S.getDiagnostics(), - ShouldAllowWarningInSystemHeader); + ForceSystemWarningsRAII SystemWarningOverrideRAII( + S.getDiagnostics(), ShouldAllowWarningInSystemHeader); if (!Message.empty()) { S.Diag(Loc, diag_message) << ReferringDecl << Message << FixIts; >From e8f7f96262a312739a990d1747a332ba6f1859b3 Mon Sep 17 00:00:00 2001 From: Anonmiraj <[email protected]> Date: Sun, 6 Sep 2026 22:53:39 +0300 Subject: [PATCH 3/4] [clang] Cache whether the documentation warnings are enabled --- clang/include/clang/Sema/Sema.h | 26 +++++++- clang/lib/Sema/Sema.cpp | 61 ++++++++++++++++--- clang/lib/Sema/SemaDecl.cpp | 3 +- .../Inputs/documentation-system-header-doc.h | 2 + .../Sema/Inputs/documentation-system-header.h | 2 + ...n-documentation-system-header-retained.cpp | 11 ++++ .../Sema/warn-documentation-system-header.cpp | 14 +++++ 7 files changed, 106 insertions(+), 13 deletions(-) create mode 100644 clang/test/Sema/Inputs/documentation-system-header-doc.h create mode 100644 clang/test/Sema/Inputs/documentation-system-header.h create mode 100644 clang/test/Sema/warn-documentation-system-header-retained.cpp create mode 100644 clang/test/Sema/warn-documentation-system-header.cpp diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h index 36fc50dcd426b..ced5a30b5c377 100644 --- a/clang/include/clang/Sema/Sema.h +++ b/clang/include/clang/Sema/Sema.h @@ -1126,10 +1126,34 @@ class Sema final : public SemaBase { void ActOnComment(SourceRange Comment); + /// Returns true if any of the documentation warnings is enabled at \p Loc. + bool areDocumentationDiagsEnabled(SourceLocation Loc); + + /// Discard the areDocumentationDiagsEnabled() cache, for when a + /// `#pragma clang diagnostic` has changed diagnostic severities. + void clearDocumentationDiagsCache(); + +private: + /// The uncached answer for both documentation groups at \p Loc. + bool computeDocumentationDiagsAt(SourceLocation Loc) const; + + /// Caches results for areDocumentationDiagsEnabled(). + /// Flushed whenever a diagnostic pragma changes severities. + /// Level one is keyed on the diagnostic state alone. + const void *DocDiagsStateKey = nullptr; + bool DocDiagsEnabledIgnoringSystem = false; + + /// Level two, for when the location does matter. Bit i of each mask is a + /// getDiagStateSystemClassForLoc() value; bit 0 is unused. + uint8_t DocDiagsExactComputed = 0; + uint8_t DocDiagsExactEnabled = 0; + +public: + /// Returns true if a comment at \p Loc should be retained in the AST /// (some consumer such as -Wdocumentation, -fparse-all-comments, code /// completion, or AST-file serialization may read it back). - bool shouldRetainCommentsInAST(SourceLocation Loc) const; + bool shouldRetainCommentsInAST(SourceLocation Loc); /// Retrieve the parser's current scope. /// diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp index f933444c22adf..586b7acd1ba10 100644 --- a/clang/lib/Sema/Sema.cpp +++ b/clang/lib/Sema/Sema.cpp @@ -227,9 +227,10 @@ class SemaPPCallbacks : public PPCallbacks { } void PragmaDiagnostic(SourceLocation Loc, StringRef Namespace, diag::Severity Mapping, StringRef Str) override { - // The pragma changed diagnostic severities; drop any cached analysis - // warning policies derived from the previous state. + // The pragma changed diagnostic severities; drop any cached state + // derived from the previous one. S->AnalysisWarnings.clearPolicyCache(); + S->clearDocumentationDiagsCache(); // If one of the analysis-based diagnostics was enabled while processing // a function, we want to note it in the analysis-based warnings so they @@ -2749,7 +2750,7 @@ LambdaScopeInfo *Sema::getCurGenericLambda() { return nullptr; } -bool Sema::shouldRetainCommentsInAST(SourceLocation Loc) const { +bool Sema::shouldRetainCommentsInAST(SourceLocation Loc) { if (!LangOpts.CommentOpts.RetainCommentsFromSystemHeaders && SourceMgr.isInSystemHeader(Loc)) return false; @@ -2769,15 +2770,55 @@ bool Sema::shouldRetainCommentsInAST(SourceLocation Loc) const { if (PP.isCodeCompletionEnabled()) return true; - // Keep the comment if any of the -Wdocumentation warnings is enabled at - // its location (checking the location handles warnings turned on by - // `#pragma clang diagnostic`). -Wdocumentation-pedantic is checked - // separately because it is not a subgroup of -Wdocumentation. - if (!Diags.areAllIgnored("documentation", Loc) || - !Diags.areAllIgnored("documentation-pedantic", Loc)) + // Keep the comment if a documentation warning is enabled at its location. + // Checking the location, rather than globally, is what makes a warning + // turned on by a `#pragma clang diagnostic` take effect. + return areDocumentationDiagsEnabled(Loc); +} + +bool Sema::computeDocumentationDiagsAt(SourceLocation Loc) const { + return !Diags.areAllIgnored("documentation", Loc) || + !Diags.areAllIgnored("documentation-pedantic", Loc); +} + +void Sema::clearDocumentationDiagsCache() { + DocDiagsStateKey = nullptr; + DocDiagsExactComputed = 0; +} + +bool Sema::areDocumentationDiagsEnabled(SourceLocation Loc) { + // Under a suppression mapping the severity depends on the file path rather + // than the diagnostic state, so there is nothing stable to key a cache on. + if (Loc.isInvalid() || Diags.hasDiagSuppressionMapping()) + return computeDocumentationDiagsAt(Loc); + + const void *StateKey = Diags.getDiagStateKeyForLoc(Loc); + if (StateKey != DocDiagsStateKey) { + DocDiagsStateKey = StateKey; + { + // Answer as if Loc were not in a system header. + ForceSystemWarningsRAII ShowSystemWarnings(Diags); + DocDiagsEnabledIgnoringSystem = computeDocumentationDiagsAt(Loc); + } + DocDiagsExactComputed = 0; + } + + if (!DocDiagsEnabledIgnoringSystem) + return false; + + unsigned SysIdx = Diags.getDiagStateSystemClassForLoc(Loc); + if (SysIdx == 0) return true; - return false; + const unsigned Bit = 1u << SysIdx; + if (!(DocDiagsExactComputed & Bit)) { + DocDiagsExactComputed |= Bit; + if (computeDocumentationDiagsAt(Loc)) + DocDiagsExactEnabled |= Bit; + else + DocDiagsExactEnabled &= ~Bit; + } + return (DocDiagsExactEnabled & Bit) != 0; } void Sema::ActOnComment(SourceRange Comment) { diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp index 8c29b30d7a8ac..d9512b82a198a 100644 --- a/clang/lib/Sema/SemaDecl.cpp +++ b/clang/lib/Sema/SemaDecl.cpp @@ -15730,8 +15730,7 @@ void Sema::ActOnDocumentableDecls(ArrayRef<Decl *> Group) { if (Group.empty() || !Group[0]) return; - if (Diags.areAllIgnored("documentation", Group[0]->getLocation()) && - Diags.areAllIgnored("documentation-pedantic", Group[0]->getLocation())) + if (!areDocumentationDiagsEnabled(Group[0]->getLocation())) return; if (Group.size() >= 2) { diff --git a/clang/test/Sema/Inputs/documentation-system-header-doc.h b/clang/test/Sema/Inputs/documentation-system-header-doc.h new file mode 100644 index 0000000000000..9cbb4493ede07 --- /dev/null +++ b/clang/test/Sema/Inputs/documentation-system-header-doc.h @@ -0,0 +1,2 @@ +/// \returns Aaa +void system_documented(); diff --git a/clang/test/Sema/Inputs/documentation-system-header.h b/clang/test/Sema/Inputs/documentation-system-header.h new file mode 100644 index 0000000000000..b41a2c37bcb48 --- /dev/null +++ b/clang/test/Sema/Inputs/documentation-system-header.h @@ -0,0 +1,2 @@ +void system_decl_one(); +void system_decl_two(); diff --git a/clang/test/Sema/warn-documentation-system-header-retained.cpp b/clang/test/Sema/warn-documentation-system-header-retained.cpp new file mode 100644 index 0000000000000..93b84f978d8bb --- /dev/null +++ b/clang/test/Sema/warn-documentation-system-header-retained.cpp @@ -0,0 +1,11 @@ +// RUN: %clang_cc1 -fsyntax-only -Wdocumentation -Wsystem-headers \ +// RUN: -fretain-comments-from-system-headers -isystem %S/Inputs \ +// RUN: -include documentation-system-header-doc.h %s 2>&1 | FileCheck %s + +// Comments in a system header normally go unchecked, because the warnings are +// off there. -Wsystem-headers turns them back on, and then the comment does +// have to be checked -- so the answer cannot be hardcoded for system headers. + +// CHECK: documentation-system-header-doc.h:1:6: warning: '\returns' command used in a comment that is attached to a function returning void + +void user_fn(); diff --git a/clang/test/Sema/warn-documentation-system-header.cpp b/clang/test/Sema/warn-documentation-system-header.cpp new file mode 100644 index 0000000000000..3a5b7fd43c9e4 --- /dev/null +++ b/clang/test/Sema/warn-documentation-system-header.cpp @@ -0,0 +1,14 @@ +// RUN: %clang_cc1 -fsyntax-only -Wdocumentation -isystem %S/Inputs \ +// RUN: -include documentation-system-header.h -verify %s + +// Clang only collects a documentation comment if a warning would read it, and +// it remembers that answer. Inside a system header the answer is 'no', so a +// declaration from one must not leave that 'no' behind for the user's own code +// -- if it does, the comment below is dropped and nothing warns about it. +// +// The header is force-included so its declarations are seen first. A comment +// read from this file first would record the right answer and hide the bug. + +/// \returns Aaa +void user_fn(); +// expected-warning@-2 {{'\returns' command used in a comment that is attached to a function returning void}} >From 9f506c7e7400c9bcb5db23f3d36adebd6a866915 Mon Sep 17 00:00:00 2001 From: Anonmiraj <[email protected]> Date: Sun, 6 Sep 2026 23:11:33 +0300 Subject: [PATCH 4/4] fix format --- clang/include/clang/Sema/Sema.h | 1 - 1 file changed, 1 deletion(-) diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h index ced5a30b5c377..928dbcd3ac589 100644 --- a/clang/include/clang/Sema/Sema.h +++ b/clang/include/clang/Sema/Sema.h @@ -1149,7 +1149,6 @@ class Sema final : public SemaBase { uint8_t DocDiagsExactEnabled = 0; public: - /// Returns true if a comment at \p Loc should be retained in the AST /// (some consumer such as -Wdocumentation, -fparse-all-comments, code /// completion, or AST-file serialization may read it back). _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
