From: Jan Kratochvil <jan.kratochvil@redhat.com>
To: Delcypher <delcypher@gmail.com>
Cc: gdb@sourceware.org
Subject: Re: Accessing std::cout and std::cin from within gdb.
Date: Fri, 21 Oct 2011 00:47:00 -0000 [thread overview]
Message-ID: <20111020214253.GA22387@host1.jankratochvil.net> (raw)
In-Reply-To: <CANNJ_ziCQSnYQ+WdXMA1fFD9cqXNFEGp3FaXG+AqiR-3n7gpMg@mail.gmail.com>
On Wed, 19 Oct 2011 23:14:24 +0200, Delcypher wrote:
> What I see is that gdb has the completely wrong address for the cin
> and cout objects.
$ nm a.out
00000000006013a0 B _ZSt4cout@@GLIBCXX_3.4
$ nm -C a.out
00000000006013a0 B std::cout@@GLIBCXX_3.4
std::cout symbol has mangled name _ZSt4cout.
$ readelf -Wr a.out | grep _ZSt4cout
00000000006013a0 0000000c00000005 R_X86_64_COPY 00000000006013a0 _ZSt4cout + 0
$ readelf -Wr /usr/lib64/libstdc++.so.6 | grep _ZSt4cout
00000000002ef688 00000a6500000006 R_X86_64_GLOB_DAT 00000000002f2d60 _ZSt4cout + 0
GDB does not handle the copy relocations well as GDB is not compliant with the
well defined ld.so symbols precedence/resolving. GDB just searches symbols in
arbitrary order and when it finds one it succeeds.
This may be a wrong/dead copy in the case of copy relocations. One should fix
it sooner it is pretty serious.
common/.bss variables from shared libraries not displayed correctly
http://sourceware.org/bugzilla/show_bug.cgi?id=11717
Thanks,
Jan
next prev parent reply other threads:[~2011-10-20 21:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-20 17:24 Delcypher
2011-10-21 0:47 ` Jan Kratochvil [this message]
2011-10-22 1:18 ` Delcypher
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