From 96980b833a21c6dc29d0dfdc8f211fb8a10256a7 Mon Sep 17 00:00:00 2001 From: Willy Tarreau Date: Wed, 23 Mar 2022 08:18:06 +0100 Subject: [PATCH] tools/nolibc/string: do not use __builtin_strlen() at -O0 clang wants to use strlen() for __builtin_strlen() at -O0. We don't really care about -O0 but it at least ought to build, so let's make sure we don't choke on this, by dropping the optimizationn for constant strings in this case. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney --- tools/include/nolibc/string.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h index 0d5e870..75a4538 100644 --- a/tools/include/nolibc/string.h +++ b/tools/include/nolibc/string.h @@ -122,7 +122,9 @@ char *strcpy(char *dst, const char *src) return ret; } -/* this function is only used with arguments that are not constants */ +/* this function is only used with arguments that are not constants or when + * it's not known because optimizations are disabled. + */ static __attribute__((unused)) size_t nolibc_strlen(const char *str) { @@ -132,11 +134,18 @@ size_t nolibc_strlen(const char *str) return len; } +/* do not trust __builtin_constant_p() at -O0, as clang will emit a test and + * the two branches, then will rely on an external definition of strlen(). + */ +#if defined(__OPTIMIZE__) #define strlen(str) ({ \ __builtin_constant_p((str)) ? \ __builtin_strlen((str)) : \ nolibc_strlen((str)); \ }) +#else +#define strlen(str) nolibc_strlen((str)) +#endif static __attribute__((unused)) size_t strlcat(char *dst, const char *src, size_t size) -- 2.7.4