Re: [PATCH v4] gdb/manual: Introduce location specs

[Eli Zaretskii via Gdb-patches <gdb-patches@sourceware.org>]

> Date: Fri, 27 May 2022 16:04:32 +0100
> Cc: gdb-patches@sourceware.org
> From: Pedro Alves <pedro@palves.net>
> 
> >   > +A concrete code location in your program is uniquely identifiable by a
> >   > +set of logical attributes.  Typically, a line number, the source file
> >   > +the line belongs to, the fully-qualified and prototyped function it is
> >   > +defined in, and an instruction address.  Because each inferior has its
> >   > +own address space, also an inferior number.
> > 
> > The "typically" part and the overall style seem to say that this is
> > not the exhaustive list of all the attributes of a code location, just
> > a general idea.  Can you please present a full exhaustive list of the
> > attributes of a code location?
> 
> I meant to remove the "typically", and forgot it, sorry.  It is not
> supposed to be there.

OK, so I take it the full list is:

  . absolute file name of the source
  . line number in the source file
  . fully-qualified and prototyped function
  . address
  . inferior number

> > And another question: does the process of resolving a location spec to
> > obtain the corresponding code locations involve only filling in of the
> > attributes that were omitted from the spec, or does it also produce
> > attributes that can _never_ be part of the location spec?  IOW, can
> > the user type a location spec which will yield a code location that is
> > 100% identical to the input spec?
> 
> Currently there's no way to explicitly specify the inferior with
> any format of location specifications.  So if you do "b func", and you
> have multiple inferiors, GDB will find code locations for "func" in all
> the inferiors.  All the other attributes you can explicitly specify.
> Not sure whether that answers your question.

I think it does, but:

>                                              I am not sure what you
> mean by "100% identical".  A spec can never the identical to the actual
> thing, the same way a cake recipe can never be identical to a cake, for
> they are things of different nature.  It can only be that the actual
> thing complies with or follows the spec.

I thought you just explained above that, when there's only one
inferior, the user can give a location spec which will resolve to a
code location that has exactly the same attributes as the spec?  IOW,
in this case the "resolution" of the spec produces a "thing" that to
the user looks exactly the same as the input spec?