Hi

Here is a rebased version of this patch.

There are few test failures when running 'make check-c++' but nothing new.

Still, there are 2 patches awaiting validation to fix some of them, PR 
c++/111524 to fix another bunch and I fear that we will have to live 
with the others.

     libstdc++: [_GLIBCXX_INLINE_VERSION] Use cxx11 abi [PR83077]

     Use cxx11 abi when activating versioned namespace mode. To do support
     a new configuration mode where !_GLIBCXX_USE_DUAL_ABI and 
_GLIBCXX_USE_CXX11_ABI.

     The main change is that std::__cow_string is now defined whenever 
_GLIBCXX_USE_DUAL_ABI
     or _GLIBCXX_USE_CXX11_ABI is true. Implementation is using 
available std::string in
     case of dual abi and a subset of it when it's not.

     On the other side std::__sso_string is defined only when 
_GLIBCXX_USE_DUAL_ABI is true
     and _GLIBCXX_USE_CXX11_ABI is false. Meaning that std::__sso_string 
is a typedef for the
     cow std::string implementation when dual abi is disabled and cow 
string is being used.

     libstdcxx-v3/ChangeLog:

             PR libstdc++/83077
             * acinclude.m4 [GLIBCXX_ENABLE_LIBSTDCXX_DUAL_ABI]: Default 
to "new" libstdcxx abi
             when enable_symvers is gnu-versioned-namespace.
             * config/locale/dragonfly/monetary_members.cc 
[!_GLIBCXX_USE_DUAL_ABI]: Define money_base
             members.
             * config/locale/generic/monetary_members.cc 
[!_GLIBCXX_USE_DUAL_ABI]: Likewise.
             * config/locale/gnu/monetary_members.cc 
[!_GLIBCXX_USE_DUAL_ABI]: Likewise.
             * config/locale/gnu/numeric_members.cc
             [!_GLIBCXX_USE_DUAL_ABI](__narrow_multibyte_chars): Define.
             * configure: Regenerate.
             * include/bits/c++config
             [_GLIBCXX_INLINE_VERSION](_GLIBCXX_NAMESPACE_CXX11, 
_GLIBCXX_BEGIN_NAMESPACE_CXX11):
             Define empty.
[_GLIBCXX_INLINE_VERSION](_GLIBCXX_END_NAMESPACE_CXX11, 
_GLIBCXX_DEFAULT_ABI_TAG):
             Likewise.
             * include/bits/cow_string.h [!_GLIBCXX_USE_CXX11_ABI]: 
Define a light version of COW
             basic_string as __std_cow_string for use in stdexcept.
             * include/std/stdexcept [_GLIBCXX_USE_CXX11_ABI]: Define 
__cow_string.
             (__cow_string(const char*)): New.
             (__cow_string::c_str()): New.
             * python/libstdcxx/v6/printers.py 
(StdStringPrinter::__init__): Set self.new_string to True
             when std::__8::basic_string type is found.
             * src/Makefile.am 
[ENABLE_SYMVERS_GNU_NAMESPACE](ldbl_alt128_compat_sources): Define empty.
             * src/Makefile.in: Regenerate.
             * src/c++11/Makefile.am (cxx11_abi_sources): Rename into...
             (dual_abi_sources): ...this. Also move cow-local_init.cc, 
cxx11-hash_tr1.cc,
             cxx11-ios_failure.cc entries to...
             (sources): ...this.
             (extra_string_inst_sources): Move cow-fstream-inst.cc, 
cow-sstream-inst.cc, cow-string-inst.cc,
             cow-string-io-inst.cc, cow-wtring-inst.cc, 
cow-wstring-io-inst.cc, cxx11-locale-inst.cc,
             cxx11-wlocale-inst.cc entries to...
             (inst_sources): ...this.
             * src/c++11/Makefile.in: Regenerate.
             * src/c++11/cow-fstream-inst.cc [_GLIBCXX_USE_CXX11_ABI]: 
Skip definitions.
             * src/c++11/cow-locale_init.cc [_GLIBCXX_USE_CXX11_ABI]: 
Skip definitions.
             * src/c++11/cow-sstream-inst.cc [_GLIBCXX_USE_CXX11_ABI]: 
Skip definitions.
             * src/c++11/cow-stdexcept.cc [_GLIBCXX_USE_CXX11_ABI]: 
Include <bits/cow_string.h>.
             [_GLIBCXX_USE_DUAL_ABI || 
_GLIBCXX_USE_CXX11_ABI](__cow_string): Redefine before
             including <stdexcept>. Define 
_GLIBCXX_DEFINE_STDEXCEPT_INSTANTIATIONS so that
             __cow_string definition in <stdexcept> is skipped.
             [_GLIBCXX_USE_CXX11_ABI]: Skip Transaction Memory TS 
definitions.
             * src/c++11/string-inst.cc: Add sizeof/alignof 
static_assert on stdexcept
             __cow_string definition.
             (_GLIBCXX_DEFINING_CXX11_ABI_INSTANTIATIONS): Define 
following _GLIBCXX_USE_CXX11_ABI
             value.
             [_GLIBCXX_USE_CXX11_ABI && 
!_GLIBCXX_DEFINING_CXX11_ABI_INSTANTIATIONS]:
             Define _GLIBCXX_DEFINING_COW_STRING_INSTANTIATIONS. Include 
<bits/cow_string.h>.
             Define basic_string as __std_cow_string for the current 
translation unit.
             * src/c++11/cow-string-inst.cc [_GLIBCXX_USE_CXX11_ABI]: 
Skip definitions.
             * src/c++11/cow-string-io-inst.cc [_GLIBCXX_USE_CXX11_ABI]: 
Skip definitions.
             * src/c++11/cow-wstring-inst.cc [_GLIBCXX_USE_CXX11_ABI]: 
Skip definitions.
             * src/c++11/cow-wstring-io-inst.cc 
[_GLIBCXX_USE_CXX11_ABI]: Skip definitions.
             * src/c++11/cxx11-hash_tr1.cc [!_GLIBCXX_USE_CXX11_ABI]: 
Skip definitions.
             * src/c++11/cxx11-ios_failure.cc [!_GLIBCXX_USE_CXX11_ABI]: 
Skip definitions.
             [!_GLIBCXX_USE_DUAL_ABI] (__ios_failure): Remove.
             * src/c++11/cxx11-locale-inst.cc: Cleanup, just include 
locale-inst.cc.
             * src/c++11/cxx11-stdexcept.cc [!_GLIBCXX_USE_CXX11_ABI]: 
Skip definitions.
             * src/c++11/cxx11-wlocale-inst.cc 
[!_GLIBCXX_USE_CXX11_ABI]: Skip definitions.
             * src/c++11/locale-inst-numeric.h
[!_GLIBCXX_USE_DUAL_ABI](std::use_facet<num_get<>>, 
std::use_facet<num_put<>>): Instantiate.
[!_GLIBCXX_USE_DUAL_ABI](std::has_facet<num_get<>>, 
std::has_facet<num_put<>>): Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](std::num_get<C, 
istreambuf_iterator<C>>): Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](std::num_put<C, 
ostreambuf_iterator<C>>): Instantiate.
             * src/c++11/locale-inst.cc [!_GLIBCXX_USE_DUAL_ABI]: Build 
only when configured
             _GLIBCXX_USE_CXX11_ABI is equal to currently built abi.
             [!_GLIBCXX_USE_DUAL_ABI](__moneypunct_cache<C, false>): 
Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](__moneypunct_cache<C, true>): 
Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](__numpunct_cache<C>): Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](__timepunct<C>): Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](__timepunct_cache<C>): Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](time_put<C, 
ostreambuf_iterator<C>>): Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](time_put_byname<C, 
ostreambuf_iterator<C>>): Instantiate.
[!_GLIBCXX_USE_DUAL_ABI](__ctype_abstract_base<C>): Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](ctype_byname<C>): Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](__codecvt_abstract_base<C, char, 
mbstate_t>): Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](codecvt_byname<C, char, 
mbstate_t>): Instantiate.
[!_GLIBCXX_USE_DUAL_ABI](use_facet<ctype<C>>(const locale&)): Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](use_facet<codecvt<C, char, 
mbstate_t>>(const locale&)): Instantiate.
[!_GLIBCXX_USE_DUAL_ABI](use_facet<__timepunct<C>>(const locale&)): 
Instantiate.
[!_GLIBCXX_USE_DUAL_ABI](use_facet<time_put<C>>(const locale&)): 
Instantiate.
[!_GLIBCXX_USE_DUAL_ABI](has_facet<ctype<C>>(const locale&)): Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](has_facet<codecvt<C, char, 
mbstate_t>>(const locale&)): Instantiate.
[!_GLIBCXX_USE_DUAL_ABI](has_facet<__timepunct<C>>(const locale&)): 
Instantiate.
[!_GLIBCXX_USE_DUAL_ABI](has_facet<time_put<C>>(const locale&)): 
Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](__add_grouping<C>): Define.
             [!_GLIBCXX_USE_DUAL_ABI](__pad<C, char_traits<C>>): 
Instantiate.
             [!_GLIBCXX_USE_DUAL_ABI](__int_to_char(C*, unsigned long, 
const C*,
             ios_base::fmtflags, bool)): Define.
             [!_GLIBCXX_USE_DUAL_ABI](__int_to_char(C*, unsigned long 
long, const C*,
             ios_base::fmtflags, bool)): Define.
             * src/c++11/wlocale-inst.cc [!_GLIBCXX_USE_CXX11_ABI]: Skip 
definitions.
             * src/c++98/Makefile.am (cxx11_abi_sources): Remove, unique 
cow-istream-string.cc entry
             move to...
             (inst_sources): ...this.
             * src/c++98/Makefile.in: Regenerate.
             * src/c++98/cow-istream-string.cc: Include <bits/c++config.h>.
             [_GLIBCXX_USE_CXX11_ABI]: Skip definitions.
             * src/c++98/hash_tr1.cc [_GLIBCXX_USE_CXX11_ABI]: Skip 
definitions.
             * src/c++98/ios_failure.cc 
[_GLIBCXX_USE_CXX11_ABI][_GLIBCXX_USE_DUAL_ABI]: Skip definitions.
             * src/c++98/istream-string.cc [!_GLIBCXX_USE_DUAL_ABI]: 
Build only when configured
             _GLIBCXX_USE_CXX11_ABI is equal to currently built abi.
             * src/c++98/locale_facets.cc 
[_GLIBCXX_USE_CXX11_ABI](__verify_grouping): Remove.
             * src/c++98/stdexcept.cc
             [_GLIBCXX_USE_CXX11_ABI](logic_error(const string&): Remove.
             [_GLIBCXX_USE_CXX11_ABI](domain_error(const string&): Remove.
             [_GLIBCXX_USE_CXX11_ABI](invalid_argument(const string&): 
Remove.
             [_GLIBCXX_USE_CXX11_ABI](length_error(const string&): Remove.
             [_GLIBCXX_USE_CXX11_ABI](out_of_range(const string&): Remove.
             [_GLIBCXX_USE_CXX11_ABI](runtime_error(const string&): Remove.
             [_GLIBCXX_USE_CXX11_ABI](range_error(const string&): Remove.
             [_GLIBCXX_USE_CXX11_ABI](overflow_error(const string&): Remove.
             [_GLIBCXX_USE_CXX11_ABI](underflow_error(const string&): 
Remove.
             * src/c++98/compatibility.cc [_GLIBCXX_USE_CXX11_ABI]: Skip 
all definitions appart from
             istream::ignore(streamsize).

Tested under Linux x64_86, ok to commit ?

François


On 17/08/2023 19:22, Jonathan Wakely wrote:
> On Sun, 13 Aug 2023 at 14:27, François Dumont via Libstdc++
> <libstdc++@gcc.gnu.org> wrote:
>> Here is the fixed patch tested in all 3 modes:
>>
>> - _GLIBCXX_USE_DUAL_ABI
>>
>> - !_GLIBCXX_USE_DUAL_ABI && !_GLIBCXX_USE_CXX11_ABI
>>
>> - !_GLIBCXX_USE_DUAL_ABI && _GLIBCXX_USE_CXX11_ABI
>>
>> I don't know what you have in mind for the change below but I wanted to
>> let you know that I tried to put COW std::basic_string into a nested
>> __cow namespace when _GLIBCXX_USE_CXX11_ABI. But it had more impact on
>> string-inst.cc so I preferred the macro substitution approach.
> I was thinking of implementing the necessary special members functions
> of __cow_string directly, so they are ABI compatible with the COW
> std::basic_string but don't actually reuse the code. That would mean
> we don't need to compile and instantiate the whole COW string just to
> use a few members from it. But that can be done later, the macro
> approach seems OK for now.
>
>> There are some test failing when !_GLIBCXX_USE_CXX11_ABI that are
>> unrelated with my changes. I'll propose fixes in coming days.
> Which tests? I run the entire testsuite with
> -D_GLIBCXX_USE_CXX11_ABI=0 several times per day and I'm not seeing
> failures.
>
> I'll review the patch ASAP, thanks for working on it.
>