RE: [PATCH 1/2] gdb: add maintenance set/show gcore xml-target-description command

["Schimpe, Christina" <christina.schimpe@intel.com>]

Hi Eli, 

Thank you for the quick review.

> -----Original Message-----
> From: Eli Zaretskii <eliz@gnu.org>
> Sent: Dienstag, 2. Juni 2026 14:22
> To: Schimpe, Christina <christina.schimpe@intel.com>
> Cc: gdb-patches@sourceware.org; hjl.tools@gmail.com; keiths@redhat.com
> Subject: Re: [PATCH 1/2] gdb: add maintenance set/show gcore xml-target-
> description command
> 
> > From: Christina Schimpe <christina.schimpe@intel.com>
> > Cc: hjl.tools@gmail.com,
> > 	keiths@redhat.com
> > Date: Tue,  2 Jun 2026 11:11:21 +0000
> >
> > From: Felix Willgerodt <felix.willgerodt@intel.com>
> >
> > This command will allow to enable/disable creating the NT_GDB_TDESC
> > note in corefiles.  While GDB writes and reads this node, there aren't
> > really many other pieces of software that create this node (e.g. the Linux
> kernel doesn't).
> > To be able to test the code path in GDB that is used when NT_GDB_TDESC
> > is not there, add a maintenance command which tests can use to test both
> cases.
> >
> > Co-authored-by:  Christina Schimpe <christina.schimpe@intel.com>
> > ---
> >  gdb/NEWS            |  6 ++++++
> >  gdb/doc/gdb.texinfo |  7 +++++++
> >  gdb/elf-none-tdep.c | 16 +++++++++-------
> >  gdb/fbsd-tdep.c     | 15 +++++++++------
> >  gdb/gcore.c         | 40 ++++++++++++++++++++++++++++++++++++++++
> >  gdb/gcore.h         |  3 +++
> >  gdb/linux-tdep.c    | 15 +++++++++------
> >  7 files changed, 83 insertions(+), 19 deletions(-)
> 
> Thanks.
> 
> > diff --git a/gdb/NEWS b/gdb/NEWS
> > index 7c8cf9af4c2..eef1924c9f0 100644
> > --- a/gdb/NEWS
> > +++ b/gdb/NEWS
> > @@ -97,6 +97,12 @@ AArch64 MinGW                   aarch64-*-mingw*
> >
> >  * New commands
> >
> > +maintenance set/show gcore xml-target-description
> > +  With this command you can control whether or not the
> > +generate-core-file
> > +  command emits the NT_GDB_TDESC note.  This is mainly useful for
> > +testing
> > +  how GDB handles corefiles without this note, as not all software
> > +that
> > +  creates corefiles generates it.
> > +
> 
> If this command controls the emission of NT_GDB_TDESC note, then why its
> name mentions a more general XML target description?  Am I right in
> assuming that NT_GDB_TDESC is just part of the target description?
> If so, perhaps the xml-target-description part should be renamed, or maybe
> the NEWS text should be modified to say that the entire target description is
> emitted as XML?

You're right. I should have been more specific.
With the NT_GDB_TDESC note the core file contains a copy of GDB's target
description XML.  Without this note the corefile does not contain the target
description (see commit "gdb: write target description into core file").

Should we better write:

"With this command you can control whether or not the generate-core-file command
emits the NT_GDB_TDESC note including a copy of GDB's target description XML."

Note that I could alternatively also generate a linux core file to test a corefile without
this note.  Then this patch is not necessary. But since it's already implemented like
that, I wanted to get some feedback if this simplified alternative is acceptable, too.

I'm adding Andrew in cc here since he is the author of the patch
"gdb: write target description into core file" and might have some feedback on this.

> 
> > --- a/gdb/doc/gdb.texinfo
> > +++ b/gdb/doc/gdb.texinfo
> > @@ -42077,6 +42077,13 @@ buffer.
> >  Control whether @value{GDBN} will skip PAD packets when computing the
> > packet history.
> >
> > +@kindex maint set gcore xml-target-description @item maint set gcore
> > +xml-target-description @kindex maint show gcore
> > +xml-target-description @item maint show gcore xml-target-description
> > +Control whether @value{GDBN} will create the NT_GDB_TDESC note when
> > +using the @samp{generate-core-file} command.
> 
> NT_GDB_TDESC should be in @code or @samp.

Thanks, will fix.

> 
> > +  add_setshow_boolean_cmd ("xml-target-description", class_obscure,
> > +			    &maint_gcore_emit_xml_tdesc, _("\ Set whether
> gcore emits a
> > +xml-target-description."), _("\ Show whether gore emits a
> > +xml-target-description."), _("\ By default, gcore emits the note
> > +NT_GDB_TDESC.\n\ Disabling this setting will cause gcore to no longer
> > +emit this note."),
> 
> This doc string has the same issue: it say GDB will emit the XML target
> description, but then goes on to say that NT_GDB_TDESC note is emitted.

Is it better as follows:
"... gcore emits the NT_GDB_TDESC note including GDB's target description XML"
 
> Reviewed-By: Eli Zaretskii <eliz@gnu.org>

Christina
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