[Bug c++/61652] New: Option --enable-libstdcxx-debug doesn't pass debug options to libstdc++.so

[Bug c++/61652] New: Option --enable-libstdcxx-debug doesn't pass debug options to libstdc++.so

[yuri at tsoft dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61652

            Bug ID: 61652
           Summary: Option --enable-libstdcxx-debug doesn't pass debug
                    options to libstdc++.so
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: yuri at tsoft dot com

Based on documentation here
https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug.html I configured gcc to
build a debug version of libstdc++.so:
$ ../src/configure --prefix=/opt/gcc/4.8.2/ --enable-libstdcxx-debug
--enable-libstdcxx-debug-flags='-g3 -O0'
$ gmake

It did build another version of libstdc++.so with different size under
lib/debug/, but both of them have local variables optimized away.

I am interested in ../src/libstdc++-v3/libsupc++/dyncast.cc, touching it and
rebuilding shows that -O0 hasn't been passed to the compile command, and it
builds with -O2.

Building gcc-4.8.2 on FreeBSD-10

[Bug c++/61652] Option --enable-libstdcxx-debug doesn't pass debug compile options to libstdc++.so

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61652

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
You don't need to use --enable-libstdcxx-debug-flags, the default is to build
the debug libs with -g3 -O0 anyway, and that works fine for me. Maybe using
--enable-libstdcxx-debug-flags breaks that, I'll check.

[Bug c++/61652] Option --enable-libstdcxx-debug doesn't build debug version of libsupc++.so

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61652

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-03-25
                 CC|jwakely.gcc at gmail dot com       |
            Summary|Option                      |Option
                   |--enable-libstdcxx-debug    |--enable-libstdcxx-debug
                   |doesn't pass debug compile  |doesn't build debug version
                   |options to libstdc++.so     |of libsupc++.so
     Ever confirmed|0                           |1

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The option works perfectly, you should be able to look in
$target/libstdc++-v3/config.log and see something like this:

  configure:17333: Debug build flags set to -g3 -O2

The problem is that libsupc++ is only build once, there's no separate
debug/libsupc++.so, and dyncast.o is part of libsupc++.