Re: [PATCH] gdb, configure: Add disable-formats option for configure

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 7 Oct 2024 16:58:16 -0300
> Cc: aburgess@redhat.com, gdb-patches@sourceware.org
> From: Guinevere Larsen <guinevere@redhat.com>
> 
> On 10/7/24 4:17 PM, Eli Zaretskii wrote:
> > That's a good starting point, but IMO it stops short of answering the
> > practical questions people will ask themselves.  For example, how do I
> > configure GDB to support a single target that is my native target and
> > OS? will specifying the single format from the above list do?
> 
> If a user wants to configure their native target, that is related to the 
> --target and --enable-target options. Not the file formats. This change 
> is not related to how a user decides to support any given CPU or 
> operating system, but rather, which binary files they wish GDB to be 
> able to understand. If the user knows they want Windows and Linux, but 
> don't know how to specify that, they should look at documentation for 
> --target and --enable-targets, which is not touched by this patch or 
> related to this change whatsoever.

I think there's a misunderstanding.  I said "to support a single
target", meaning _only_ that single target.

You seem to be saying that --target is what I want, but that's not
what I knew.  Right now, when I compile GDB for native Windows
debugging, I get all the *read.c files compiled and linked into GDB.
I don't specify --target when I build GDB, but I do specify --build,
and I thought that --build=FOO is a short for --host=FOO --target=FOO.
So I thought that I am already specifying --target, and yet I get all
the binary-format readers compiled and linked in.  So I was asking
what should I do at configure time to have only the *read.c files I
need for that single target and only for native debugging.

If you are saying that the --enable-binary-format is unrelated to my
questions, then I guess I'm even more confused than I thought I was.

> > One thing I remember is that many targets produce core files in ELF
> > format.  If that is true, then omitting ELF should be discouraged for
> > that reason.  And maybe also other similar practical factoids.
> >
> I believe that is the case because there are many targets that use ELF 
> as the objfile format.

True, but not what I was saying: I was specifically alluding to
targets whose objfile format is _not_ ELF, and yet they produce core
files in ELF format.  ISTR that Cygwin is one such target?  I'm sure
others here will be able to find more examples.

> And once again, users don't need to interact with this feature. If it is 
> completely ignored, GDB will continue to work just as it did before this 
> patch went in.

I understand, and that is good, but I'm talking from the POV of
someone who _wants_ to use this new feature, in order to make GDB
smaller.

Thanks.