Re: [PATCH v3 20/21] dyndbg: add user-flag, negating-flags, and filtering on flags

jim.cromie
2020-06-17T22:58:13Z

On Wed, Jun 17, 2020 at 4:13 PM Joe Perches <joe@perches.com> wrote:
>
> On Wed, 2020-06-17 at 10:25 -0600, Jim Cromie wrote:
> > 1. Add a user-flag [u] which works like the [pfmlt] flags, but has no
> > effect on callsite behavior; it allows incremental marking of
> > arbitrary sets of callsites.
> >
> > 2. Add [PFMLTU] flags, which negate their counterparts; P===!p etc.
> > And in ddebug_read_flags():
> > current code does: [pfmltu_] -> flags
> > copy it to: [PFMLTU_] -> mask
> >
> > also disallow both of a pair: ie no 'pP', no true & false.
> >
> > 3. Add filtering ops into ddebug_change(), right after all the
> > callsite-property selections are complete. These filter on the
> > callsite's current flagstate before applying modflags.
> >
> > Why ?
> >
> > The u-flag & filter flags
> >
> > The 'u' flag lets the user assemble an arbitary set of callsites.
> > Then using filter flags, user can activate the 'u' callsite set.
> >
> > #> echo 'file foo.c +u; file bar.c +u' > control # and repeat
> > #> echo 'u+p' > control
> >
> > Of course, you can continue to just activate your set without ever
> > marking it 1st, but you could trivially add the markup as you go, then
> > be able to use it as a constraint later, to undo or modify your set.
>
> Does this set selection also allow for selection by
> increasing decimal level?
>
> Can sites be enabled for a value less than x?
>
>

no, theres no levels added here.
that would be a variation on the WIP pr-class patch in v2, dropped from v3

legacy dyndbg - select on RO callsite info only - file, module, func, line.
flag state is write only.
filterflags - additionally select on callsite's flagstate, ie
reading the current flagstate

please look at the export patch 15/21
for how I now think levels, and drm.debug=0x03 can be done.