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. --- include/monetary.h | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/monetary.h b/include/monetary.h index c130ed56a3..f59bdf9150 100644 --- a/include/monetary.h +++ b/include/monetary.h @@ -2,7 +2,18 @@ #ifndef _ISOMAC #include -extern ssize_t __vstrfmon_l (char *s, size_t maxsize, locale_t loc, - const char *format, va_list ap) - attribute_hidden; +extern ssize_t +__vstrfmon_l_internal (char *s, size_t maxsize, locale_t loc, + const char *format, va_list ap, + unsigned int flags) + attribute_hidden; + +/* Flags for __vstrfmon_l_internal. + + STRFMON_LDBL_IS_DBL is a one-bit mask for the flags parameter that + indicates whether long double values are to be handled as having the + same format as double, in which case the flag should be set to one, + or as another format, otherwise. */ +#define STRFMON_LDBL_IS_DBL 0x0001 + #endif -- cgit v1.2.1