From: Jianzhou Zhao <jianzhou@seas.upenn.edu>
To: Mark Shinwell <mshinwell@janestreet.com>
Cc: caml-list@yquem.inria.fr
Subject: Re: [Caml-list] Debugging C and OCaml
Date: Mon, 1 Mar 2010 19:48:56 -0500 [thread overview]
Message-ID: <9dfe358d1003011648g58c07831p9b27bc76276a9461@mail.gmail.com> (raw)
In-Reply-To: <20100301151940.GD26002@janestreet.com>
On Mon, Mar 1, 2010 at 10:19 AM, Mark Shinwell <mshinwell@janestreet.com> wrote:
> On Mon, Mar 01, 2010 at 10:10:44AM -0500, Jianzhou Zhao wrote:
>> My main program is C++. It uses C functions to call
>> OCaml functions, and these OCaml functions also call
>> C functions and wrapped C++ functions sometimes.
>>
>> I can debug from C++, but it stops when it meets
>> an OCaml binding. Does anyone know an efficient
>> solution about how to debug across different languages?
>
> Is this native code compilation?
I compiled OCaml code into *.o by 'ocamlc -custom -output-obj...',
and then linked it with *.o from C and C++ code.
I think this isnt a native compilation.
My main C++ program is eventually compiled into a shared library.
If I do 'ocamlopt', ld reports:
/usr/lib64/gcc/x86_64-suse-linux/4.3/../../../../x86_64-suse-linux/bin/ld:
/mnt/eclipse/acg/users/jianzhou/tools/ocaml-3.11.2//lib/ocaml/libasmrun.a(amd64.o):
relocation R_X86_64_PC32 against symbol `caml_last_return_address' can
not be used when making a shared object; recompile with -fPIC
So I am doing ''ocamlc -custom' for the time being.
>
> If so, you should be able to use gdb to debug into the Caml bindings at the
> assembly level -- does that work? Unfortunately at the moment there is no Caml
> compiler support for emitting the debug info required by gdb to debug at the
> language level. That said, ocamlopt-compiled assembly code is fairly easy to
> read, and you should be able to get something resembling a backtrace using
> "where".
Now I can debug into OCaml assembly from C, and its stack frames.
#0 0x00007ffff6cad3f4 in caml_interprete ()
#1 0x00007ffff6caa54f in caml_callbackN_exn ()
#2 0x00007ffff6caa64a in caml_callback_exn ()
#3 0x00007ffff6caa658 in caml_callback ()
...
It seems that OCaml runtime is interpreting via 'caml_interprete' the
OCaml function which C
calls at runtime. If this is true, we cannot really debug that OCaml
function, but we can
see how it is interpreted. But I guess we can debug the real assembly if I do
native compilation.
>
> Mark
>
--
Jianzhou
next prev parent reply other threads:[~2010-03-02 0:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-01 15:10 Jianzhou Zhao
2010-03-01 15:19 ` [Caml-list] " Mark Shinwell
2010-03-01 19:24 ` rixed
2010-03-01 19:27 ` Mark Shinwell
2010-03-02 9:50 ` rixed
2010-03-02 0:48 ` Jianzhou Zhao [this message]
2010-03-02 0:52 ` Jianzhou Zhao
2010-03-02 7:36 ` Mark Shinwell
2010-03-02 7:42 ` Mark Shinwell
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