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| author | Jonathan Wakely <jwakely@redhat.com> | 2024-10-04 12:08:12 +0100 |
|---|---|---|
| committer | Jonathan Wakely <redi@gcc.gnu.org> | 2024-10-09 14:05:49 +0100 |
| commit | 5247ee086f7fff5c6e7cd837478974dbfc2782db (patch) | |
| tree | 35822468138779c5879bf92432497b3d183819b8 | |
| parent | c0bc9a153ae6ab649e2fcc3af53ebcd37df0a871 (diff) | |
| download | gcc-5247ee086f7fff5c6e7cd837478974dbfc2782db.zip gcc-5247ee086f7fff5c6e7cd837478974dbfc2782db.tar.gz gcc-5247ee086f7fff5c6e7cd837478974dbfc2782db.tar.bz2 | |
libstdc++: Drop format attribute from snprintf wrapper [PR116969]
When __LONG_DOUBLE_IEEE128__ is defined we need to declare a wrapper for
Glibc's 'snprintf' symbol, so we can call the original definition that
works with the IBM128 format of long double. Because we were declaring
the wrapper using __typeof__(__builtin_snprintf) it inherited the
__attribute__((format(printf, 3, 4))) decoration, and then we got a
warning for calling that wrapper with an __ibm128 argument for a %Lf
conversion specifier. The warning is bogus, because the function we're
calling really does want __ibm128 for %Lf, but there's no "printf but
with a different long double format" archetype for the attribute.
In r15-4039-g28911f626864e7 I added a diagnostic pragma to suppress the
warning, but it would be better to just declare the wrapper without the
attribute, and not have to suppress a warning for code that we know is
actually correct.
libstdc++-v3/ChangeLog:
PR libstdc++/116969
* include/bits/locale_facets_nonio.tcc (money_put::__do_put):
Remove diagnostic pragmas.
(__glibcxx_snprintfibm128): Declare type manually, instead of
using __typeof__(__builtin_snprintf).
| -rw-r--r-- | libstdc++-v3/include/bits/locale_facets_nonio.tcc | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/libstdc++-v3/include/bits/locale_facets_nonio.tcc b/libstdc++-v3/include/bits/locale_facets_nonio.tcc index 53553d1..863350a 100644 --- a/libstdc++-v3/include/bits/locale_facets_nonio.tcc +++ b/libstdc++-v3/include/bits/locale_facets_nonio.tcc @@ -637,10 +637,14 @@ _GLIBCXX_BEGIN_NAMESPACE_LDBL_OR_CXX11 #if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \ && defined __LONG_DOUBLE_IEEE128__ -#pragma GCC diagnostic push -#pragma GCC diagnostic ignored "-Wformat" // '%Lf' expects 'long double' -extern "C" -__typeof__(__builtin_snprintf) __glibcxx_snprintfibm128 __asm__("snprintf"); +// The snprintf symbol in glibc that works with __ibm128 format is not visible +// when compiling with -mabi=ieeelongdouble so we use this name for it instead. +// N.B. we don't use __typeof__(__builtin_snprintf) for the type because that +// would inherit __attribute__((format(printf, 3, 4))) and give a warning for +// passing __ibm128 to %Lf instead of long double. The warning would be wrong +// because long double in this TU is __ieee128 and snprintf expects __ibm128. +extern "C" int +__glibcxx_snprintfibm128(char*, size_t, const char*, ...) __asm__("snprintf"); template<typename _CharT, typename _OutIter> _OutIter @@ -673,7 +677,6 @@ __typeof__(__builtin_snprintf) __glibcxx_snprintfibm128 __asm__("snprintf"); return __intl ? _M_insert<true>(__s, __io, __fill, __digits) : _M_insert<false>(__s, __io, __fill, __digits); } -#pragma GCC diagnostic pop #endif _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11 |