https://github.com/xgupta created https://github.com/llvm/llvm-project/pull/216556
When comments are preserved with -C, a comment at the start of a physical line consumes the PhysicalStartOfLine state. As a result, a preprocessor directive following the comment is not recognized. Preserve the PhysicalStartOfLine state when returning a comment token so that directives following comments are still handled correctly. Fixes: #48361 >From 0ba17ad78a0cb6b0a687a3204e265a66d5fef7b4 Mon Sep 17 00:00:00 2001 From: Shivam Gupta <[email protected]> Date: Sun, 16 Aug 2026 15:24:41 +0530 Subject: [PATCH] [clang][Lex] Preserve physical line start after comments in -C mode When comments are preserved with -C, a comment at the start of a physical line consumes the PhysicalStartOfLine state. As a result, a preprocessor directive following the comment is not recognized. Preserve the PhysicalStartOfLine state when returning a comment token so that directives following comments are still handled correctly. Fixes: #48361 --- clang/docs/ReleaseNotes.md | 1 + clang/lib/Lex/Lexer.cpp | 1 + clang/test/Preprocessor/comment_directive.c | 33 +++++++++++++++++++++ 3 files changed, 35 insertions(+) create mode 100644 clang/test/Preprocessor/comment_directive.c diff --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md index 70ea2e35090c6..979a268e23d3a 100644 --- a/clang/docs/ReleaseNotes.md +++ b/clang/docs/ReleaseNotes.md @@ -412,6 +412,7 @@ features cannot lower the translation-unit ABI level; - Clang now defines the GCC-compatible predefined macro `__SIG_ATOMIC_TYPE__`. (#GH213895) - Fixed an ICE that occurred when a structured binding pack is expanded outside the lambda where it was declared. (#GH214160) - Fixed a bug where a stray closing curley brace in an OpenMP/OpenACC pragma could cause pragma parsing issues when inside of a member function. (#GH214195) +- Fixed a bug where preprocessor directives following comments were not correctly recognized when using -C. (#GH48361) #### Bug Fixes to Compiler Builtins diff --git a/clang/lib/Lex/Lexer.cpp b/clang/lib/Lex/Lexer.cpp index 37e33861c4470..fe6a11f29b73b 100644 --- a/clang/lib/Lex/Lexer.cpp +++ b/clang/lib/Lex/Lexer.cpp @@ -3163,6 +3163,7 @@ bool Lexer::SkipBlockComment(Token &Result, const char *CurPtr) { // If we are returning comments as tokens, return this comment as a token. if (inKeepCommentMode()) { FormTokenWithChars(Result, CurPtr, tok::comment); + IsAtPhysicalStartOfLine = Result.isAtPhysicalStartOfLine(); return true; } diff --git a/clang/test/Preprocessor/comment_directive.c b/clang/test/Preprocessor/comment_directive.c new file mode 100644 index 0000000000000..980ae4a233e08 --- /dev/null +++ b/clang/test/Preprocessor/comment_directive.c @@ -0,0 +1,33 @@ +// RUN: %clang_cc1 -E -C %s | FileCheck %s + +/* comment */ #define A 1 +int a = A; + +/* + * multiline comment + */ #define B 2 +int b = B; + +int c; /* comment */ #define C 3 +int d = C; + +int e; /* + * multiline comment + */ #define D 4 +int f = D; + +// CHECK: /* comment */ +// CHECK-NEXT: int a = 1; + +// CHECK: /* +// CHECK-NEXT: * multiline comment +// CHECK-NEXT: */ +// CHECK-NEXT: int b = 2; + +// CHECK: int c; /* comment */ #define C 3 +// CHECK-NEXT: int d = C; + +// CHECK: int e; /* +// CHECK-NEXT: * multiline comment +// CHECK-NEXT: */ #define D 4 +// CHECK-NEXT: int f = D; _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
