https://github.com/AnonMiraj updated https://github.com/llvm/llvm-project/pull/206363
>From ba4ada54cbed3d44680a0811c261536a1021f2f6 Mon Sep 17 00:00:00 2001 From: Anonmiraj <[email protected]> Date: Sun, 28 Jun 2026 22:27:23 +0300 Subject: [PATCH 1/2] [clang] Don't add comments to the AST if not requested --- clang/include/clang/Lex/PreprocessorOptions.h | 5 ++++ clang/include/clang/Sema/Sema.h | 5 ++++ clang/lib/Frontend/ASTUnit.cpp | 6 ++++ clang/lib/Parse/Parser.cpp | 11 +++++-- clang/lib/Sema/Sema.cpp | 29 +++++++++++++++++++ 5 files changed, 53 insertions(+), 3 deletions(-) diff --git a/clang/include/clang/Lex/PreprocessorOptions.h b/clang/include/clang/Lex/PreprocessorOptions.h index 4d1a30712836f..5d695e5f0e875 100644 --- a/clang/include/clang/Lex/PreprocessorOptions.h +++ b/clang/include/clang/Lex/PreprocessorOptions.h @@ -157,6 +157,11 @@ class PreprocessorOptions { /// clients don't use them. bool WriteCommentListToPCH = true; + /// 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; + /// When enabled, preprocessor is in a mode for parsing a single file only. /// /// Disables #includes of other files and if there are unresolved identifiers diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h index 2cf16fac83282..b818f4c4c4a60 100644 --- a/clang/include/clang/Sema/Sema.h +++ b/clang/include/clang/Sema/Sema.h @@ -1130,6 +1130,11 @@ 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 shouldRetainCommentsFromLexer(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/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp index 2974cf2660184..404761c4488f7 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->getPreprocessorOpts().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->getPreprocessorOpts().RetainComments = true; Invocation->getFrontendOpts().DisableFree = false; getDiagnostics().Reset(); ProcessWarningOptions(getDiagnostics(), Invocation->getDiagnosticOpts(), diff --git a/clang/lib/Parse/Parser.cpp b/clang/lib/Parse/Parser.cpp index 5e1fd4df1a3f0..6b7c4bce6645c 100644 --- a/clang/lib/Parse/Parser.cpp +++ b/clang/lib/Parse/Parser.cpp @@ -74,8 +74,12 @@ Parser::Parser(Preprocessor &pp, Sema &actions, bool skipFunctionBodies) // destructor. initializePragmaHandlers(); - CommentSemaHandler.reset(new ActionCommentHandler(actions)); - PP.addCommentHandler(CommentSemaHandler.get()); + // Only install the comment handler when some consumer may read documentation + // comments back. + if (actions.shouldRetainCommentsFromLexer(SourceLocation())) { + CommentSemaHandler.reset(new ActionCommentHandler(actions)); + PP.addCommentHandler(CommentSemaHandler.get()); + } PP.setCodeCompletionHandler(*this); @@ -481,7 +485,8 @@ Parser::~Parser() { resetPragmaHandlers(); - PP.removeCommentHandler(CommentSemaHandler.get()); + if (CommentSemaHandler) + PP.removeCommentHandler(CommentSemaHandler.get()); PP.clearCodeCompletionHandler(); diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp index 78fbc9e31842d..7a7329c271716 100644 --- a/clang/lib/Sema/Sema.cpp +++ b/clang/lib/Sema/Sema.cpp @@ -24,6 +24,7 @@ #include "clang/AST/StmtCXX.h" #include "clang/AST/TypeOrdering.h" #include "clang/Basic/DarwinSDKInfo.h" +#include "clang/Basic/DiagnosticComment.h" #include "clang/Basic/DiagnosticOptions.h" #include "clang/Basic/PartialDiagnostic.h" #include "clang/Basic/SourceManager.h" @@ -31,6 +32,7 @@ #include "clang/Lex/HeaderSearch.h" #include "clang/Lex/HeaderSearchOptions.h" #include "clang/Lex/Preprocessor.h" +#include "clang/Lex/PreprocessorOptions.h" #include "clang/Sema/CXXFieldCollector.h" #include "clang/Sema/EnterExpressionEvaluationContext.h" #include "clang/Sema/ExternalSemaSource.h" @@ -2704,10 +2706,37 @@ LambdaScopeInfo *Sema::getCurGenericLambda() { } +bool Sema::shouldRetainCommentsFromLexer(SourceLocation Loc) const { + if (LangOpts.CommentOpts.ParseAllComments) + return true; + + if (PP.getPreprocessorOpts().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 -Wdocumentation is enabled at its location (checking + // the location handles warnings turned on by `#pragma clang diagnostic`). + if (!Diags.isIgnored(diag::warn_doc_param_not_found, Loc) || + !Diags.isIgnored(diag::warn_unknown_comment_command_name, Loc)) + return true; + + return false; +} + void Sema::ActOnComment(SourceRange Comment) { if (!LangOpts.RetainCommentsFromSystemHeaders && SourceMgr.isInSystemHeader(Comment.getBegin())) return; + if (!shouldRetainCommentsFromLexer(Comment.getBegin())) + return; RawComment RC(SourceMgr, Comment, LangOpts.CommentOpts, false); if (RC.isAlmostTrailingComment() || RC.hasUnsupportedSplice(SourceMgr)) { SourceRange MagicMarkerRange(Comment.getBegin(), >From 402fcc0771fc98940295fd1b4d55dfce8379f98b Mon Sep 17 00:00:00 2001 From: Anonmiraj <[email protected]> Date: Sun, 28 Jun 2026 22:41:05 +0300 Subject: [PATCH 2/2] fix formatting --- clang/lib/Sema/Sema.cpp | 1 - 1 file changed, 1 deletion(-) diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp index 7a7329c271716..b44a710907134 100644 --- a/clang/lib/Sema/Sema.cpp +++ b/clang/lib/Sema/Sema.cpp @@ -2705,7 +2705,6 @@ LambdaScopeInfo *Sema::getCurGenericLambda() { return nullptr; } - bool Sema::shouldRetainCommentsFromLexer(SourceLocation Loc) const { if (LangOpts.CommentOpts.ParseAllComments) return true; _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
