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Re: [RFC] Add support of software single step to process record
On Wednesday 23 December 2009 09:23:21, Hui Zhu wrote:
> + Â Â Âstruct gdbarch *gdbarch = target_thread_architecture (ptid);
> +
> Â Â Â Ârecord_message (get_current_regcache (), signal);
> Â Â Â Ârecord_beneath_to_resume (record_beneath_to_resume_ops, ptid, 1,
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Âsignal);
Why is this resume call still present?
> +
> + Â Â Â if (gdbarch_software_single_step_p (gdbarch))
> + Â Â Â Â {
> + Â Â Â Â Â if (!inserted_single_step_breakpoint_p ())
Isn't this naming stale? I thought you had renamed this.
> + Â Â Â Â Â Â gdbarch_software_single_step (gdbarch, get_current_frame ());
> + Â Â Â Â Â record_beneath_to_resume (record_beneath_to_resume_ops,
> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â ptid, step, signal);
> + Â Â Â Â Â record_resume_step = 0;
> + Â Â Â Â }
> + Â Â Â else
> + Â Â Â Â record_beneath_to_resume (record_beneath_to_resume_ops, ptid, 1,
> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â signal);
> Â Â Â}
>
You've got the predicates a bit mixed up.
- gdbarch_software_single_step_p purpose is only "is there or
not a gdbarch_software_single_step callback registered in
this gdbarch"? It returning true does not mean that
software single-step should be used for that single-step.
- gdbarch_software_single_step can return false, meaning,
no software single-step needs to be used.
This is how stepping over atomic sequences is handled
currently (grep for deal_with_atomic_sequence):
gdbarch_software_single_step_p returns true, but
gdbarch_software_single_step returns false most
of the times. See also infrun.c:maybe_software_singlestep.
I think you want this:
if (!step
&& gdbarch_software_single_step_p (gdbarch)
&& !single_step_breakpoints_inserted ()
&& gdbarch_software_single_step (gdbarch, get_current_frame ()))
record_resume_step = 0;
else
record_resume_step = 1;
record_beneath_to_resume (record_beneath_to_resume_ops, ptid,
record_resume_step, signal);
If `step' is true when record_resume is called, and so is
gdbarch_software_single_step_p, then it must be that infrun.c
already determined that gdbarch_software_single_step returns
false, otherwise, `step' would be false (maybe_software_singlestep).
If `step' is false (the user is requesting a continue), and
no single-step breakpoints are inserted yet, but,
gdbarch_software_single_step returns false, we have ourselves
an arch/target combo that only wants software single-stepping
for atomic sequences, e.g., MIPS (non-linux), or PPC. If
so, we should force hardware single-step in the target
beneath (set record_resume_step to 1).
--
Pedro Alves