Re: [PATCH] Add missing gnu-versioned-namespace symbols

[Jonathan Wakely <jwakely@redhat.com>]

On 01/11/20 20:48 +0100, François Dumont via Libstdc++ wrote:
>Several tests are failing because of those missing symbols.
>
>I understand why we need to export symbols relying in the versioned 
>namespace but I don't understand why we need to do it for 
>_GLIBCXX_DEBUG symbols which are not version namespace dependant.

If you don't export the symbol, it can't be found by code linking to
libstdc++.so.8

This linker script is the only one used to build libstdc++.so.8 so all
symbols that need to be exported by that library have to be exported
by this script. Nothing exports that debug symbol unless you add it
here.

What I don't understand is why the __istream_extract symbol isn't
matched by the wildcard in the extern "C++" block at the top of the
file.

>Do you want to backport the Debug symbol ?
>
>    libstdc++: Add mising gnu-versioned-namespace symbols
>
>    libstdc++-v3/ChangeLog:
>
>            * config/abi/pre/gnu-versioned-namespace.ver:
>            Add __istream_extract and 
>_Safe_local_iterator_base::_M_attach_single
>            symbols.
>
>Tested under Linux x86_64 versioned namespace.
>
>Ok to commit ?
>
>François
>

>diff --git a/libstdc++-v3/config/abi/pre/gnu-versioned-namespace.ver b/libstdc++-v3/config/abi/pre/gnu-versioned-namespace.ver
>index 0965854fbc3..3b6d7944d06 100644
>--- a/libstdc++-v3/config/abi/pre/gnu-versioned-namespace.ver
>+++ b/libstdc++-v3/config/abi/pre/gnu-versioned-namespace.ver
>@@ -98,6 +98,9 @@ GLIBCXX_8.0 {
>     _ZNSt3__817__copy_streambufsI*;
>     _ZNSt3__821__copy_streambufs_eofI*;
> 
>+    # std::__istream_extract(wistream&, wchar_t*, streamsize)
>+    _ZNSt3__817__istream_extractIwNS_11char_traitsIwEEEEvRNS_13basic_istreamIT_T0_EEPS4_[ilx];
>+
>     # __gnu_cxx::__atomic_add
>     # __gnu_cxx::__exchange_and_add
>     _ZN9__gnu_cxx3__812__atomic_addEPV[il][il];
>@@ -145,6 +148,7 @@ GLIBCXX_8.0 {
>     _ZN11__gnu_debug30_Safe_unordered_container_base13_M_detach_allEv;
>     _ZN11__gnu_debug25_Safe_local_iterator_base9_M_attachEPNS_19_Safe_sequence_baseEb;
>     _ZN11__gnu_debug25_Safe_local_iterator_base9_M_detachEv;
>+    _ZN11__gnu_debug25_Safe_local_iterator_base16_M_attach_singleEPNS_19_Safe_sequence_baseEb;
> 
>     # parallel mode
>     _ZN14__gnu_parallel9_Settings3getEv;