From c75772e3f079b9265738e2f54644ee47f932d99a Mon Sep 17 00:00:00 2001 From: Zack Weinberg Date: Wed, 7 Mar 2018 14:31:57 -0500 Subject: Use STRFMON_LDBL_IS_DBL instead of __ldbl_is_dbl. On platforms where long double used to have the same format as double, but later switched to a different format (alpha, s390, sparc, and powerpc), accessing the older behavior is possible and it happens via __nldbl_* functions (not on the API, but accessible from header redirection and from compat symbols). These functions write to the global flag __ldbl_is_dbl, which tells other functions that long double variables should be handled as double. This patch takes the first step towards removing this global flag and creates __vstrfmon_l_internal, which takes an explicit flags parameter. This change arguably makes the generated code slightly worse on architectures where __ldbl_is_dbl is never true; right now, on those architectures, it's a compile-time constant; after this change, the compiler could theoretically prove that __vstrfmon_l_internal was never called with a nonzero flags argument, but it would probably need LTO to do it. This is not performance critical code and I tend to think that the maintainability benefits of removing action at a distance are worth it. However, we _could_ wrap the runtime flag check with a macro that was defined to ignore its argument and always return false on architectures where __ldbl_is_dbl is never true, if people think the codegen benefits are important. Tested for powerpc and powerpc64le. --- stdlib/strfmon.c | 3 ++- stdlib/strfmon_l.c | 8 ++++---- 2 files changed, 6 insertions(+), 5 deletions(-) (limited to 'stdlib') diff --git a/stdlib/strfmon.c b/stdlib/strfmon.c index 01980d3..3058b3e 100644 --- a/stdlib/strfmon.c +++ b/stdlib/strfmon.c @@ -30,7 +30,8 @@ __strfmon (char *s, size_t maxsize, const char *format, ...) va_start (ap, format); - ssize_t res = __vstrfmon_l (s, maxsize, _NL_CURRENT_LOCALE, format, ap); + ssize_t res = __vstrfmon_l_internal (s, maxsize, _NL_CURRENT_LOCALE, + format, ap, 0); va_end (ap); diff --git a/stdlib/strfmon_l.c b/stdlib/strfmon_l.c index cd3796c..5293104 100644 --- a/stdlib/strfmon_l.c +++ b/stdlib/strfmon_l.c @@ -76,8 +76,8 @@ too. Some of the information contradicts the information which can be specified in format string. */ ssize_t -__vstrfmon_l (char *s, size_t maxsize, locale_t loc, const char *format, - va_list ap) +__vstrfmon_l_internal (char *s, size_t maxsize, locale_t loc, + const char *format, va_list ap, unsigned int flags) { struct __locale_data *current = loc->__locales[LC_MONETARY]; _IO_strfile f; @@ -268,7 +268,7 @@ __vstrfmon_l (char *s, size_t maxsize, locale_t loc, const char *format, if (*fmt == 'L') { ++fmt; - if (!__ldbl_is_dbl) + if (__glibc_likely ((flags & STRFMON_LDBL_IS_DBL) == 0)) is_long_double = 1; } @@ -608,7 +608,7 @@ ___strfmon_l (char *s, size_t maxsize, locale_t loc, const char *format, ...) va_start (ap, format); - ssize_t res = __vstrfmon_l (s, maxsize, loc, format, ap); + ssize_t res = __vstrfmon_l_internal (s, maxsize, loc, format, ap, 0); va_end (ap); -- cgit v1.1