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Re: [PATCH 0/1] Build GDB as a C++ program by default
- From: Eli Zaretskii <eliz at gnu dot org>
- To: Pedro Alves <palves at redhat dot com>
- Cc: simon dot marchi at ericsson dot com, gdb-patches at sourceware dot org
- Date: Tue, 19 Apr 2016 18:59:24 +0300
- Subject: Re: [PATCH 0/1] Build GDB as a C++ program by default
- Authentication-results: sourceware.org; auth=none
- References: <1461000466-31668-1-git-send-email-palves at redhat dot com> <571633C8 dot 4060803 at ericsson dot com> <57163E3B dot 50101 at redhat dot com> <83d1pl8xje dot fsf at gnu dot org> <571648CD dot 7070705 at redhat dot com> <838u098vxk dot fsf at gnu dot org> <5716516E dot 4020607 at redhat dot com>
- Reply-to: Eli Zaretskii <eliz at gnu dot org>
> From: Pedro Alves <firstname.lastname@example.org>
> Cc: email@example.com, firstname.lastname@example.org
> Date: Tue, 19 Apr 2016 16:40:30 +0100
> >> GDB links with libgcc even when built as a C program.
> > Not here, it doesn't. It is linked statically against libgcc.
> I don't see how linking statically removes the requirement to
> provide access to sources.
It does, because there's a special clause for that in the L?GPL, whch
only holds for static linking.
> I get, on a C++ gdb build:
> $ objdump -x gdb.exe | fgrep "DLL Name:"
> DLL Name: KERNEL32.dll
> DLL Name: msvcrt.dll
> DLL Name: libwinpthread-1.dll
> DLL Name: USER32.dll
> DLL Name: WS2_32.dll
Then there's no problem, and I apologize for the noise. I thought
your previous message meant that there was a dynamic dependency on
libstdc++ DLL, sorry for my misunderstanding.
> >> How's C++ any different?
> > With C, you can get away by using "CC='gcc -static-libgcc'" at
> > configure time, but can you do the same with -static-libstdc++?
> You shouldn't even need that. We already link with
> -static-libstdc++ -static-libgcc:
IME, programs that use libtool cannot easily do that, because libtool
removes any switches it doesn't know about from the GCC command line.
> x86_64-w64-mingw32-g++ -g -O2 -static-libstdc++ -static-libgcc -Wl,--stack,12582912 \
> -o gdb.exe gdb.o armbsd-tdep.o arm.o arm-linux.o arm-linux-tdep.o arm-get-next-pcs.o arm-symbian-tdep.o armnbsd-tdep.o
> And we also link that way when building as a C program.
> We haven't done anything specific to have that on the gdb side, it
> comes from the top level somewhere, I think originally for GCC, long
Good, then the problem I feared doesn't really exist. Thanks for
clearing that up.
> Since GCC is already building this way for a long time, it should not
> be a problem for GDB either. Or at least if it is a problem, it's
> one you would already have with GCC.
I see too many precompiled binaries out there that depend on libgcc
DLL. Most people think it is not a problem, so we don't hear any
complaints. So the fact that GCC builds this way is in itself not an
evidence the problem doesn't exist. For someone like myself, who
tries to be 100% GPL compatible with the binaries I make available,
having a GCC dependency is a huge downside, so I go an extra mile to
Once again, I'm happy to know there' no such problem with GDB.