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Re: gdb-7.12 powerpc-rtems4.12-gdb does not build on FreeBSD.


On 24/11/2016 11:15, John Baldwin wrote:
On Thursday, November 24, 2016 10:16:10 AM Chris Johns wrote:
On 23/11/2016 10:38, Chris Johns wrote:
Hi,

I am getting:

../sim/ppc/libsim.a(sim_calls.o): In function `sim_io_printf_filtered':
../../../gdb-7.12/sim/ppc/sim_calls.c:(.text+0x17c): undefined reference
to `error'
../sim/ppc/libsim.a(sim_calls.o): In function `sim_load':
../../../gdb-7.12/sim/ppc/sim_calls.c:(.text+0x291): undefined reference
to `error'
../../../gdb-7.12/sim/ppc/sim_calls.c:(.text+0x31d): undefined reference
to `error'
../../../gdb-7.12/sim/ppc/sim_calls.c:(.text+0x357): undefined reference
to `error'
../sim/ppc/libsim.a(sim_calls.o): In function `sim_create_inferior':
../../../gdb-7.12/sim/ppc/sim_calls.c:(.text+0x53e): undefined reference
to `error'

and errors.o has the following symbols:

   nm
build/powerpc-rtems4.12-gdb-7.12-x86_64-freebsd10.3-1/build/gdb/errors.o
0000000000000120 T _Z14internal_errorPKciS0_z
                   U _Z15internal_verrorPKciS0_P13__va_list_tag
00000000000001a0 T _Z16internal_warningPKciS0_z
                   U _Z17internal_vwarningPKciS0_P13__va_list_tag
0000000000000090 T _Z5errorPKcz
                   U _Z6verrorPKcP13__va_list_tag
0000000000000000 T _Z7warningPKcz
                   U _Z8vwarningPKcP13__va_list_tag

Is there a C++/C thing happening here between the PCC simulator and GDB?


A follow up. It looks like GDB is being built by cc which is clang on
FreeBSD. I am told by Joel this gdb target builds on Linux.

I do not know what the extern binding is for gdb, C or C++?

clang vs gcc shouldn't really break this.

Yes I agree.

What undefined symbols do you see
in the nm of sim_calls.o?

The symbol is `error` and in my original post I showed the output of nm for the errors.o object file and `error` symbol is mangled. One thing that confuses me is only this symbol is being reported and there must be other calls to gdb.

Looking at sim/ppc/Makefile.in, it only references CC, not CXX, so I would not
be surprised if it compiles as C without mangled symbols giving the error you
have.

Interesting. I will take a closer look. Maybe something on Linux is building the sim/ppc as C++ and this does not happen with clang.

I think 7.12 can still be built as C, though you might need to use a
configure flag to do so?

Really? I see code in 'gdbtypes.h' of 'enum type_code { ... }' and that looks C++ and not C to me.

 If you see non-mangled symbols from sim_calls.o, I
would try building 7.12 as plain C to see if that fixes it for now.

I will take a look and report back. If this works I will need to consider the path we take as doing this complicates the build matrix for RTEMS where we have a number of hosts and possibly differing versions of gdb across the supported architectures.

Thanks
Chris


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