https://github.com/venk-ks updated https://github.com/llvm/llvm-project/pull/224111
>From 5145a0390082283071641bd6571913c17f4cd55e Mon Sep 17 00:00:00 2001 From: Venkatesh Srinivasan <[email protected]> Date: Wed, 16 Sep 2026 18:35:57 +0000 Subject: [PATCH 1/2] [Clang][Docs] Add documentation for -Wfortify-source Document the -Wfortify-source diagnostic group in DiagnosticGroups.td covering all currently checked library functions. Part of #142230 Assisted-by: Gemini --- clang/include/clang/Basic/DiagnosticGroups.td | 30 ++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td index 1da7698944b24..5f53deead39c6 100644 --- a/clang/include/clang/Basic/DiagnosticGroups.td +++ b/clang/include/clang/Basic/DiagnosticGroups.td @@ -1897,7 +1897,35 @@ def CrossTURemarks : DiagGroup<"ctu-remarks">; def CTADMaybeUnsupported : DiagGroup<"ctad-maybe-unsupported">; -def FortifySource : DiagGroup<"fortify-source", [FormatOverflow, FormatTruncation]>; +def FortifySource : DiagGroup<"fortify-source", [FormatOverflow, FormatTruncation]> { + code Documentation = [{ +Warns at compile time when calls to standard C library or POSIX functions have +provably out-of-bounds destination buffers or invalid constant arguments, +modeled after [`_FORTIFY_SOURCE`](https://www.gnu.org/software/libc/manual/html_node/Source-Fortification.html) +compile-time checks. + +This diagnostic group checks: + +1. **Destination buffer overflows and format truncation**: Diagnoses when a + write operation will always overflow the destination buffer, when an + explicit size argument exceeds the known size of the destination buffer, or + when formatted output will always be truncated: + - `<string.h>` / `<strings.h>`: `memcpy`, `memmove`, `memset`, `mempcpy`, + `bcopy`, `bzero`, `strcpy`, `stpcpy`, `strcat`, `strncpy`, `stpncpy`, + `strncat`, `strlcpy`, `strlcat` (and their `__builtin_` variants). + - `<stdio.h>`: `sprintf`, `snprintf`, `vsnprintf` (format overflow and + truncation also controlled by {ref}`-Wformat-overflow` and + {ref}`-Wformat-truncation`), and `scanf`, `fscanf`, `sscanf`. + +2. **Invalid constant arguments**: + - `<sys/stat.h>`: `umask` when called with constant mode bits outside `0777` + that are silently ignored. + +Note: Related bounds checks for most `__builtin___*_chk` functions and source buffer +overreads in memory functions (such as `memcpy` and `memcmp`) are controlled +separately by {ref}`-Wbuiltin-memcpy-chk-size` and {ref}`-Wstringop-overread`. + }]; +} def OverflowBehaviorAttributeIgnored : DiagGroup<"overflow-behavior-attribute-ignored">; >From b6db8d0e23b535d4617d97229db0a738a468f262 Mon Sep 17 00:00:00 2001 From: Venkatesh Srinivasan <[email protected]> Date: Fri, 25 Sep 2026 18:06:05 +0000 Subject: [PATCH 2/2] [Clang][Docs] Fix _FORTIFY_SOURCE manual link in DiagnosticGroups.td --- clang/include/clang/Basic/DiagnosticGroups.td | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td index 5f53deead39c6..a21321f748cf4 100644 --- a/clang/include/clang/Basic/DiagnosticGroups.td +++ b/clang/include/clang/Basic/DiagnosticGroups.td @@ -1901,7 +1901,7 @@ def FortifySource : DiagGroup<"fortify-source", [FormatOverflow, FormatTruncatio code Documentation = [{ Warns at compile time when calls to standard C library or POSIX functions have provably out-of-bounds destination buffers or invalid constant arguments, -modeled after [`_FORTIFY_SOURCE`](https://www.gnu.org/software/libc/manual/html_node/Source-Fortification.html) +modeled after [`_FORTIFY_SOURCE`](https://sourceware.org/glibc/manual/latest/html_node/Source-Fortification.html) compile-time checks. This diagnostic group checks: _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
