* [PATCH] tools/nolibc: avoid call to wcslen() in _start_c() inserted by clang
@ 2026-04-18 10:31 Thomas Weißschuh
2026-04-19 15:32 ` Willy Tarreau
0 siblings, 1 reply; 2+ messages in thread
From: Thomas Weißschuh @ 2026-04-18 10:31 UTC (permalink / raw)
To: Willy Tarreau; +Cc: linux-kernel, Thomas Weißschuh
Clang may convert the loop to find _auxv into a call to wcslen() which
is missing on nolibc. -fsanitize needs to be disabled for this to
happen.
Use the same pattern as in the nolibc strlen() implementation to avoid
the function call generation.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
tools/include/nolibc/crt.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h
index d8ce91fd2e3b..f38590a05adf 100644
--- a/tools/include/nolibc/crt.h
+++ b/tools/include/nolibc/crt.h
@@ -89,7 +89,7 @@ void _start_c(long *sp)
/* find _auxv */
for (auxv = (void *)envp; *auxv++;)
- ;
+ __asm__("");
_auxv = auxv;
#ifndef NOLIBC_IGNORE_ERRNO
---
base-commit: b5ac9d2dc1330d0b16a141962ac202739b091efd
change-id: 20260418-nolibc-wcslen-5afac8eb318b
Best regards,
--
Thomas Weißschuh <linux@weissschuh.net>
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] tools/nolibc: avoid call to wcslen() in _start_c() inserted by clang
2026-04-18 10:31 [PATCH] tools/nolibc: avoid call to wcslen() in _start_c() inserted by clang Thomas Weißschuh
@ 2026-04-19 15:32 ` Willy Tarreau
0 siblings, 0 replies; 2+ messages in thread
From: Willy Tarreau @ 2026-04-19 15:32 UTC (permalink / raw)
To: Thomas Weißschuh; +Cc: linux-kernel
On Sat, Apr 18, 2026 at 12:31:54PM +0200, Thomas Weißschuh wrote:
> Clang may convert the loop to find _auxv into a call to wcslen() which
> is missing on nolibc. -fsanitize needs to be disabled for this to
> happen.
>
> Use the same pattern as in the nolibc strlen() implementation to avoid
> the function call generation.
>
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Compilers are always full of surprises!
Acked-by: Willy Tarreau <w@1wt.eu>
Willy
^ permalink raw reply [flat|nested] 2+ messages in thread
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