[PATCH][_GLIBCXX_INLINE_VERSION] Adapt to_chars/from_chars symbols

[Jonathan Wakely]

On Mon, 28 Nov 2022 at 10:10, Jonathan Wakely <jwakely@redhat.com> wrote:

>
>
> On Mon, 28 Nov 2022 at 06:07, François Dumont via Libstdc++ <
> libstdc++@gcc.gnu.org> wrote:
>
>> This patch is fixing those tests:
>>
>> 20_util/to_chars/float128_c++23.cc
>> std/format/formatter/requirements.cc
>> std/format/functions/format.cc
>> std/format/functions/format_to_n.cc
>> std/format/functions/size.cc
>> std/format/functions/vformat_to.cc
>> std/format/string.cc
>>
>> Note that symbols used in <format> for __ibm128 and __iee128 are untested.
>>
>> I even wonder if the normal mode ones are because I cannot find the
>> symbols used in gnu.ver.
>>
>>
>>      libstdc++: [_GLIBCXX_INLINE_VERSION] Add to_chars/from_chars
>> symbols export
>>
>>      libstdc++-v3/ChangeLog
>>
>>              * include/std/format [_GLIBCXX_INLINE_VERSION](to_chars):
>> Adapt __asm symbol
>>              specifications.
>>              * config/abi/pre/gnu-versioned-namespace.ver: Add
>> to_chars/from_chars symbols
>>              export.
>>
>> Ok to commit ?
>>
>>
>
> Why are changes needed to the linker script?
>
> Those functions should already match the general wildcard:
>
>     # Names inside the 'extern' block are demangled names.
>     extern "C++"
>     {
>       std::*;
>       std::__8::*;
>     };
>
>
>

Instead of nine separate #if blocks, can we just do:

#if _GLIBCXX_INLINE_VERSION
# define _GLIBCXX_ALIAS(S) __asm("_ZNSt3__8" S)
#else
# define _GLIBCXX_ALIAS(S) __asm("_ZNSt" S)
#endif

 And then use:

  _GLIBCXX_ALIAS("8to_charsPcS_eSt12chars_format");

and finally:

#undef _GLIBCXX_ALIAS