Hi!
This is an ABI problem on powerpc64le-linux, introduced in 13.1.
When libstdc++ is configured against old glibc, the
_ZSt10from_charsPKcS0_RDF128_St12chars_format@@GLIBCXX_3.4.31
_ZSt8to_charsPcS_DF128_@@GLIBCXX_3.4.31
_ZSt8to_charsPcS_DF128_St12chars_format@@GLIBCXX_3.4.31
_ZSt8to_charsPcS_DF128_St12chars_formati@@GLIBCXX_3.4.31
symbols are exported from the library, while when it is configured against
new enough glibc, those symbols aren't exported and we export instead
_ZSt10from_charsPKcS0_Ru9__ieee128St12chars_format@@GLIBCXX_IEEE128_3.4.29
_ZSt8to_charsPcS_u9__ieee128@@GLIBCXX_IEEE128_3.4.29
_ZSt8to_charsPcS_u9__ieee128St12chars_format@@GLIBCXX_IEEE128_3.4.29
_ZSt8to_charsPcS_u9__ieee128St12chars_formati@@GLIBCXX_IEEE128_3.4.29
together with various other @@GLIBCXX_IEEE128_3.4.{29,30,31} and
@@CXXABI_IEEE128_1.3.13 symbols. The idea was that those *IEEE128* symbol
versions (similarly to *LDBL* symbol versions) are optional (but if it
appears, all symbols from it up to the version of the library appears),
but the base appears always.
My _Float128 from_chars/to_chars changes unfortunately broke this.
I believe nothing really uses those symbols if libstdc++ has been
configured against old glibc, so if 13.1 wasn't already released, it might
be best to make sure they aren't exported on powerpc64le-linux.
But as they were exported, I think the best resolution for this ABI
difference is to add those 4 symbols as aliases to the
GLIBCXX_IEEE128_3.4.29 *u9__ieee128* symbols, which the following patch
does.
Tested on powerpc64le-linux (both configured against glibc 2.36 and 2.17)
and powerpc64-linux (configured against glibc 2.17), ok for trunk?
2023-05-03 Jakub Jelinek <ja...@redhat.com>
* src/c++17/floating_from_chars.cc
(_ZSt10from_charsPKcS0_RDF128_St12chars_format): New alias to
_ZSt10from_charsPKcS0_Ru9__ieee128St12chars_format.
* src/c++17/floating_to_chars.cc (_ZSt8to_charsPcS_DF128_): New alias to
_ZSt8to_charsPcS_u9__ieee128.
(_ZSt8to_charsPcS_DF128_St12chars_format): New alias to
_ZSt8to_charsPcS_u9__ieee128St12chars_format.
(_ZSt8to_charsPcS_DF128_St12chars_formati): New alias to
_ZSt8to_charsPcS_u9__ieee128St12chars_formati.
* config/abi/post/powerpc64le-linux-gnu/baseline_symbols.txt: Updated.
--- libstdc++-v3/src/c++17/floating_from_chars.cc.jj 2023-04-13
23:00:36.125459347 +0200
+++ libstdc++-v3/src/c++17/floating_from_chars.cc 2023-05-03
17:24:45.121600206 +0200
@@ -1272,6 +1272,13 @@ from_chars(const char* first, const char
// fast_float doesn't support IEEE binary128 format, but we can use strtold.
return from_chars_strtod(first, last, value, fmt);
}
+
+extern "C" from_chars_result
+_ZSt10from_charsPKcS0_RDF128_St12chars_format(const char* first,
+ const char* last,
+ __ieee128& value,
+ chars_format fmt) noexcept
+__attribute__((alias ("_ZSt10from_charsPKcS0_Ru9__ieee128St12chars_format")));
#elif defined(USE_STRTOF128_FOR_FROM_CHARS)
from_chars_result
from_chars(const char* first, const char* last, _Float128& value,
--- libstdc++-v3/src/c++17/floating_to_chars.cc.jj 2023-01-16
23:19:06.284716774 +0100
+++ libstdc++-v3/src/c++17/floating_to_chars.cc 2023-05-03 17:12:16.766877278
+0200
@@ -1851,6 +1851,23 @@ to_chars(char* first, char* last, __floa
{
return __floating_to_chars_precision(first, last, value, fmt, precision);
}
+
+extern "C" to_chars_result
+_ZSt8to_charsPcS_DF128_(char* first, char* last, __float128 value) noexcept
+ __attribute__((alias ("_ZSt8to_charsPcS_u9__ieee128")));
+
+extern "C" to_chars_result
+_ZSt8to_charsPcS_DF128_St12chars_format(char* first, char* last,
+ __float128 value,
+ chars_format fmt) noexcept
+ __attribute__((alias ("_ZSt8to_charsPcS_u9__ieee128St12chars_format")));
+
+extern "C" to_chars_result
+_ZSt8to_charsPcS_DF128_St12chars_formati(char* first, char* last,
+ __float128 value,
+ chars_format fmt,
+ int precision) noexcept
+ __attribute__((alias ("_ZSt8to_charsPcS_u9__ieee128St12chars_formati")));
#else
to_chars_result
to_chars(char* first, char* last, _Float128 value) noexcept
--- libstdc++-v3/config/abi/post/powerpc64le-linux-gnu/baseline_symbols.txt.jj
2023-05-02 19:27:47.538504941 +0200
+++ libstdc++-v3/config/abi/post/powerpc64le-linux-gnu/baseline_symbols.txt
2023-05-03 19:06:33.389469841 +0200
@@ -4491,6 +4491,7 @@ FUNC:_ZNSt9type_infoD1Ev@@GLIBCXX_3.4
FUNC:_ZNSt9type_infoD2Ev@@GLIBCXX_3.4
FUNC:_ZNVSt9__atomic011atomic_flag12test_and_setESt12memory_order@@GLIBCXX_3.4.11
FUNC:_ZNVSt9__atomic011atomic_flag5clearESt12memory_order@@GLIBCXX_3.4.11
+FUNC:_ZSt10from_charsPKcS0_RDF128_St12chars_format@@GLIBCXX_3.4.31
FUNC:_ZSt10from_charsPKcS0_RdSt12chars_format@@GLIBCXX_3.4.29
FUNC:_ZSt10from_charsPKcS0_ReSt12chars_format@@GLIBCXX_3.4.29
FUNC:_ZSt10from_charsPKcS0_RfSt12chars_format@@GLIBCXX_3.4.29
@@ -4641,6 +4642,9 @@ FUNC:_ZSt7getlineIwSt11char_traitsIwESaI
FUNC:_ZSt7getlineIwSt11char_traitsIwESaIwEERSt13basic_istreamIT_T0_ES7_RNSt7__cxx1112basic_stringIS4_S5_T1_EES4_@@GLIBCXX_3.4.21
FUNC:_ZSt7getlineIwSt11char_traitsIwESaIwEERSt13basic_istreamIT_T0_ES7_RSbIS4_S5_T1_E@@GLIBCXX_3.4
FUNC:_ZSt7getlineIwSt11char_traitsIwESaIwEERSt13basic_istreamIT_T0_ES7_RSbIS4_S5_T1_ES4_@@GLIBCXX_3.4
+FUNC:_ZSt8to_charsPcS_DF128_@@GLIBCXX_3.4.31
+FUNC:_ZSt8to_charsPcS_DF128_St12chars_format@@GLIBCXX_3.4.31
+FUNC:_ZSt8to_charsPcS_DF128_St12chars_formati@@GLIBCXX_3.4.31
FUNC:_ZSt8to_charsPcS_d@@GLIBCXX_3.4.29
FUNC:_ZSt8to_charsPcS_dSt12chars_format@@GLIBCXX_3.4.29
FUNC:_ZSt8to_charsPcS_dSt12chars_formati@@GLIBCXX_3.4.29
Jakub
