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tools/nolibc/string: do not use __builtin_strlen() at -O0

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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 <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Willy Tarreau 2022-03-23 08:18:06 +01:00 • committed by Paul E. McKenney
parent 0b37dff10b
commit 96980b833a
1 changed files with 10 additions and 1 deletions
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11
tools/include/nolibc/string.h
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@ -122,7 +122,9 @@ char *strcpy(char *dst, const char *src)
return ret; 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)) static __attribute__((unused))
size_t nolibc_strlen(const char *str) size_t nolibc_strlen(const char *str)
{ {
@ -132,11 +134,18 @@ size_t nolibc_strlen(const char *str)
return len; 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) ({ \ #define strlen(str) ({ \
__builtin_constant_p((str)) ? \ __builtin_constant_p((str)) ? \
__builtin_strlen((str)) : \ __builtin_strlen((str)) : \
nolibc_strlen((str)); \ nolibc_strlen((str)); \
}) })
#else
#define strlen(str) nolibc_strlen((str))
#endif
static __attribute__((unused)) static __attribute__((unused))
size_t strlcat(char *dst, const char *src, size_t size) size_t strlcat(char *dst, const char *src, size_t size)