Re: [PATCH] gdb: add callback defines for new ARGV handling

[Doug Evans <dje@google.com>]

On Mon, Jan 10, 2011 at 1:25 PM, Mike Frysinger <vapier@gentoo.org> wrote:
> On Mon, Jan 10, 2011 at 12:57 PM, Doug Evans wrote:
>> On Thu, Jan 6, 2011 at 2:15 AM, Mike Frysinger wrote:
>>> The common sim code has slightly unfinished support for these already,
>>> but even arch ports are unable to handle these if the common header does
>>> not define them.  This is because the generated callback header includes
>>> simple common gdb/sim headers only which causes it to skip the new ARGV
>>> syscalls.  Plus, it isn't like providing these in the common header will
>>> break any sim targets which don't want them.
>>>
>>> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
>>>
>>> 2010-01-06  Mike Frysinger  <vapier@gentoo.org>
>>>
>>>        * callback.h (CB_SYS_argc, CB_SYS_argnlen, CB_SYS_argn): Define.
>>> ---
>>>  include/gdb/callback.h |    5 +++++
>>>  1 files changed, 5 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/include/gdb/callback.h b/include/gdb/callback.h
>>> index a1f79f9..296dfc3 100644
>>> --- a/include/gdb/callback.h
>>> +++ b/include/gdb/callback.h
>>> @@ -231,6 +231,11 @@ extern host_callback default_callback;
>>>  #define CB_SYS_truncate        21
>>>  #define CB_SYS_ftruncate 22
>>>  #define CB_SYS_pipe    23
>>> +
>>> +/* New ARGV support.  */
>>> +#define CB_SYS_argc    24
>>> +#define CB_SYS_argnlen 25
>>> +#define CB_SYS_argn    26
>>>
>>>  /* Struct use to pass and return information necessary to perform a
>>>    system call.  */
>>
>> The common sim code has CB_SYS_{argv,argvlen}, but I don't see the above.
>> Where do they come from?
>
> pretty much all the callback "syscalls" that the sim handles are
> because of newlib/libgloss
> -mike

Ah.  src/libgloss/syscall.h has SYS_{argc,argnlen,argn}, added in 2006.

So now we have CB_SYS_{argv,argvlen,argc,argnlen,argn}.
Blech.
It would be nice to know the reasoning behind argn,argnlen.

For callback.h, IWBN to add some documentation regarding why things
are the way they are.  E.g. if argn is preferred over argv, why?

Any ideas?