Re: libsupc++, _cxa references, and Dinkum libcpp

[<gp at qnx dot com>]

Here is the output of a simple C++ compile using gcc-3.2.3 and our port of the
Dinkum libcpp.  The Dinkumware implements 'new' and 'delete', but it has not
presented as a problem yet, except if we try to use the libsupc++ to resolve
the cxa symbols.  Which is why I thought that splitting the cxa stuff into a
libcxa (that would also be linked into the libsupc++) would work.  The symbols
in libsupc++ that conflict (multiple definitions) are:

  std::terminate()
  std::unexpected()
  std::set_terminate(void (*)())
  std::set_unexpected(void (*)())

It seems to me that cc1plus should not be emitting libstdc++ specific symbols,
thereby assuming that the c++ libs being used are only going to be GNU
libstdc++.  Failing that, providing a libcxa of some kind would be very helpful.

Comments?  Corrections?  Clarifications?

Thanks.
GP

$ /usr/bin/ntox86-ld -b elf32-i386 -m i386nto --dynamic-linker
/usr/lib/ldqnx.so.2 /x86/lib/crt1.o /x86/lib/crti.o
/usr/lib/gcc-lib/ntox86/3.2.3/crtbegin.o t182c01.o
-L/home/gp/cvs/lib/c_res_2/lib/x86/a -L/home/gp/cvs/lib/cpp_res_2/x86/a -lcpp
-lc -o a.out -Y/x86/lib:/x86/usr/lib -L/usr/lib/gcc-lib/ntox86/3.2.3
-L/x86/lib /usr/lib/gcc-lib/ntox86/3.2.3/libgcc.a -lc -dn -Bstatic -lc
/usr/lib/gcc-lib/ntox86/3.2.3/libgcc.a /usr/lib/gcc-lib/ntox86/3.2.3/crtend.o
/x86/lib/crtn.o
/home/gp/cvs/gcc_3.2.3/tools/gcc/nto-x86-o-ntox86/ntox86/libstdc++-v3/libsupc++/.libs/libsupc++.a
/home/gp/cvs/gcc_3.2.3/tools/gcc/nto-x86-o-ntox86/ntox86/libstdc++-v3/libsupc++/.libs/libsupc++.a(eh_terminate.o):
In function `std::set_unexpected(void (*)())':
/home/gp/cvs/gcc_3.2.3/tools/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:83:
multiple definition of `std::terminate()'
/home/gp/cvs/lib/cpp_res_2/x86/a/libcpp.a(exceptio.o)(.text+0x5c): first
defined here 
/usr/bin/ntox86-ld: Warning: size of symbol `_ZSt9terminatev' changed from 22
to 32 in
/home/gp/cvs/gcc_3.2.3/tools/gcc/nto-x86-o-ntox86/ntox86/libstdc++-v3/libsupc++/.libs/libsupc++.a(eh_terminate.o)
/home/gp/cvs/gcc_3.2.3/tools/gcc/nto-x86-o-ntox86/ntox86/libstdc++-v3/libsupc++/.libs/libsupc++.a(eh_terminate.o):
In function `std::set_unexpected(void (*)())':
/home/gp/cvs/gcc_3.2.3/tools/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:83:
multiple definition of `std::unexpected()'
/home/gp/cvs/lib/cpp_res_2/x86/a/libcpp.a(exceptio.o)(.text+0xc4): first
defined here
/usr/bin/ntox86-ld: Warning: size of symbol `_ZSt10unexpectedv' changed from
28 to 32 in
/home/gp/cvs/gcc_3.2.3/tools/gcc/nto-x86-o-ntox86/ntox86/libstdc++-v3/libsupc++/.libs/libsupc++.a(eh_terminate.o)
/home/gp/cvs/gcc_3.2.3/tools/gcc/nto-x86-o-ntox86/ntox86/libstdc++-v3/libsupc++/.libs/libsupc++.a(eh_terminate.o):
In function `std::set_unexpected(void (*)())':
/home/gp/cvs/gcc_3.2.3/tools/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:83:
multiple definition of `std::set_terminate(void (*)())'
/home/gp/cvs/lib/cpp_res_2/x86/a/libcpp.a(exceptio.o)(.text+0xc): first
defined here
/usr/bin/ntox86-ld: Warning: size of symbol `_ZSt13set_terminatePFvvE' changed
from 77 to 34 in
/home/gp/cvs/gcc_3.2.3/tools/gcc/nto-x86-o-ntox86/ntox86/libstdc++-v3/libsupc++/.libs/libsupc++.a(eh_terminate.o)
/home/gp/cvs/gcc_3.2.3/tools/gcc/nto-x86-o-ntox86/ntox86/libstdc++-v3/libsupc++/.libs/libsupc++.a(eh_terminate.o):
In function `std::set_unexpected(void (*)())':
/home/gp/cvs/gcc_3.2.3/tools/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:83:
multiple definition of `std::set_unexpected(void (*)())'
/home/gp/cvs/lib/cpp_res_2/x86/a/libcpp.a(exceptio.o)(.text+0x74): first
defined here
/usr/bin/ntox86-ld: Warning: size of symbol `_ZSt14set_unexpectedPFvvE'
changed from 77 to 34 in
/home/gp/cvs/gcc_3.2.3/tools/gcc/nto-x86-o-ntox86/ntox86/libstdc++-v3/libsupc++/.libs/libsupc++.a(eh_terminate.o)

Joe Buck <jbuck@synopsys.com> said:

> On Fri, May 16, 2003 at 09:07:31PM -0000, gp@qnx.com wrote:
> > I'm working on porting gcc-3.2.3 to the various QNX platforms.  We use both
> > libstdc++ and Dinkumware libcpp for C++.  The difficulty here is that gcc
> > (actually cc1plus I think) is emitting __cxa* symbols, like the call:
> > 
> >   push_throw_library_fn (get_identifier ("__cxa_call_unexpected"), tmp);
> > 
> > in gcc/cp/except.c:init_exception_processing().  So when I build the
> > Dinkumware with gcc-3.2.3, the libcpp ends up with these undefined references
> > to various __cxa symbols.  These symbols are in libsupc++, but so are a number
> > of other symbols that conflict with the Dinkumware.
> 
> Which symbols conflict?  Is Dinkumware attempting to provide fundamental
> C++ support routines such as the default operator new?  If so, then
> there's likely to be more work to do than just separating symbols, since
> you'll need to have support library functions that correctly interact with
> whatever Dinkumware provides.
> 



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