Re: [RFC 1/2] Remove linux-waitpid.c debugging code

[Pedro Alves <palves at redhat dot com>]

On 6/3/19 5:32 PM, Tom Tromey wrote:
>>>>>> "Simon" == Simon Marchi <simark@simark.ca> writes:
> 
>>> My first thought was that this code is not extremely useful, so this
>>> patch removes this code.  (However, if it is actually useful to
>>> someone, we could make it work by introducing a new abstraction.)
> 
> Simon> Pedro probably has a stronger opinion about this (as he is probably the one who
> Simon> has spent the most time staring at those logs), but I would think that this
> Simon> logging is useful when debugging interactions with the kernel.
> 
> I should have mentioned that the reason I figured it wasn't that useful
> is that it's not available in gdb proper, only gdbserver.

A bit of history here:

IIRC, the original reason my_waitpid in gdbserver printed the result, is
that I found that useful when I made my_waitpid emulate __WALL:

https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=gdb/gdbserver/linux-low.c;h=ba1d7b46bb96e4cec83ea698e40511d284f16532;hb=bd99dc858385792aad304d42f4a47791fd8d3272#l2110

Over the years, the function moved to gdb/nat/, gdb started using it too,
and then the __WALL emulation disappeared, making my_waitpid a simple
EINTR wrapper again.

Since the emulation is gone, and, both gdb and gdbserver print the result
of waitpid in the most interesting waitpid call spot:

      if (debug_threads)
	debug_printf ("LWFE: waitpid(-1, ...) returned %d, %s\n",
		      ret, errno ? strerror (errno) : "ERRNO-OK");


      if (debug_linux_nat)
	fprintf_unfiltered (gdb_stdlog,
			    "LNW: waitpid(-1, ...) returned %d, %s\n",
			    lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");

... I guess I won't terribly miss it.

Thanks,
Pedro Alves