On Mon, Nov 07, 2022 at 05:48:42PM +0000, Jonathan Wakely wrote:
> On Mon, 7 Nov 2022 at 16:11, Joseph Myers <jos...@codesourcery.com> wrote:
> >
> > On Wed, 2 Nov 2022, Jakub Jelinek via Gcc-patches wrote:
> >
> > > APIs. So that one can build gcc against older glibc and then compile
> > > user programs on newer glibc, the patch uses weak references unless
> > > gcc is compiled against glibc 2.26+. strfromf128 unfortunately can't
> >
> > This support for older glibc doesn't actually seem to be working, on an
> > older system with glibc 2.19 I'm seeing
> >
> > /scratch/jmyers/fsf/gcc-mainline/libstdc++-v3/src/c++17/floating_to_chars.cc:52:3:
> > error: expected initializer before '__asm'
> > 52 | __asm ("strfromf128");
> > | ^~~~~
> >
> > and a series of subsequent errors.
>
> This seems to "fix" it (not sure if it's right though):
>
> #ifndef _GLIBCXX_HAVE_FLOAT128_MATH
> extern "C" _Float128 __strtof128(const char*, char**)
> __attribute__((__weak__));
> #endif
> extern "C" _Float128 __strtof128(const char*, char**)
> __asm ("strtof128");
It is, but floating_from_chars.cc has the same problem,
and I think we can avoid the duplication, like this:
2022-11-07 Jakub Jelinek <ja...@redhat.com>
* src/c++17/floating_from_chars.cc (__strtof128): Put __asm before
__attribute__.
* src/c++17/floating_to_chars.cc (__strfromf128): Likewise.
--- libstdc++-v3/src/c++17/floating_from_chars.cc.jj 2022-11-07
15:15:42.928314819 +0100
+++ libstdc++-v3/src/c++17/floating_from_chars.cc 2022-11-07
20:09:47.267983154 +0100
@@ -63,10 +63,11 @@ extern "C" __ieee128 __strtoieee128(cons
&& defined(__GLIBC_PREREQ)
#define USE_STRTOF128_FOR_FROM_CHARS 1
extern "C" _Float128 __strtof128(const char*, char**)
+ __asm ("strtof128")
#ifndef _GLIBCXX_HAVE_FLOAT128_MATH
__attribute__((__weak__))
#endif
- __asm ("strtof128");
+ ;
#endif
#if _GLIBCXX_FLOAT_IS_IEEE_BINARY32 && _GLIBCXX_DOUBLE_IS_IEEE_BINARY64 \
--- libstdc++-v3/src/c++17/floating_to_chars.cc.jj 2022-11-07
15:15:42.929314805 +0100
+++ libstdc++-v3/src/c++17/floating_to_chars.cc 2022-11-07 20:10:13.189627684
+0100
@@ -46,10 +46,11 @@ extern "C" int __sprintfieee128(char*, c
#elif __FLT128_MANT_DIG__ == 113 && __LDBL_MANT_DIG__ != 113 \
&& defined(__GLIBC_PREREQ)
extern "C" int __strfromf128(char*, size_t, const char*, _Float128)
+ __asm ("strfromf128")
#ifndef _GLIBCXX_HAVE_FLOAT128_MATH
__attribute__((__weak__))
#endif
- __asm ("strfromf128");
+ ;
#endif
// This implementation crucially assumes float/double have the
Jakub
