RE: [PATCH v2 7/9] gdb: Provide gdbarch hook to distinguish shadow stack backtrace elements.

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

> -----Original Message-----
> From: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
> Sent: Dienstag, 12. Mai 2026 05:49
> To: Schimpe, Christina <christina.schimpe@intel.com>
> Cc: gdb-patches@sourceware.org
> Subject: Re: [PATCH v2 7/9] gdb: Provide gdbarch hook to distinguish shadow
> stack backtrace elements.
> 
> Christina Schimpe <christina.schimpe@intel.com> writes:
> 
> > index 1f24a3a6d72..d39cba6e016 100644
> > --- a/gdb/gdbarch_components.py
> > +++ b/gdb/gdbarch_components.py
> > @@ -2911,3 +2911,24 @@ In case shadow stack is not enabled for the
> current thread, return -1.
> >      ],
> >      predicate=True,
> >  )
> > +
> > +Method(
> > +    comment="""
> > +There can be elements on the shadow stack which are not return
> addresses.
> > +This happens for example on x86 with CET in case of signals.
> > +If an architecture implements the command options 'backtrace -shadow'
> > +and the shadow stack can contain elements which are not return
> > +addresses, this function has to be provided.
> > +
> > +Return true, if FRAME does not contain a return address in
> > +FRAME->VALUE but another valid value for the architecture's shadow
> > +stack.  In this case, also the string frame_type has to be configured
> > +to display the type in the shadow stack backtrace.
> > +""",
> > +    type="bool",
> > +    name="is_no_return_shadow_stack_address",
> > +    params=[
> > +        ("const shadow_stack_frame_info &", "frame"),
> > +        ("std::string &", "frame_type")],
> > +    predicate=True,
> > +)
> 
> Small nit: here the Black code formatter also makes a change:
> 
>      name="is_no_return_shadow_stack_address",
>      params=[
>          ("const shadow_stack_frame_info &", "frame"),
> -        ("std::string &", "frame_type")],
> +        ("std::string &", "frame_type"),
> +    ],
>      predicate=True,
>  )

Yes, I will run Black before posting v3.

> I also like Tom's idea of using a std::optional<std::string> for frame_type, but
> regardless of whether you decide to adopt it:
> 
> Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
> 

Yes, I like that too. With the interface changes 
(https://sourceware.org/pipermail/gdb-patches/2026-May/227481.html )
I might even return an entire  optional shadow stack frame.

Thank you for the review,
Christina
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