Re: [hpux] Improve sigtramp frame identification

[Randolph Chung <randolph@tausq.org>]

> Hmm, here's an alternative approach: if we're in an export stub, look
> if the stub leads us to a function that has HP_UX_interrupt_marker set
> in its unwind record.  This makes us read an instruction from the
> inferior, but it should be pretty robust.
> 
> ok?

Hrm, this seems to assume that you are sitting at a specific insn of the 
export stub when doing unwinding. We should be able to unwind from any 
insn in the export stub, right?

> Now that signal trampolines get detected again on HP-UX 10.20, I
> noticed another recent change that seems to have broken things. Your
> recent overhaul of hppa_hpux_sigtramp_frame_unwind_cache added these
> two lines:
> 
>   info->saved_regs[HPPA_PCOQ_HEAD_REGNUM].addr = 
>     info->saved_regs[HPPA_RP_REGNUM].addr;
> 
> This breaks stuff, since at least on HP-UX 10.20 %pcoqh as read from
> the signal state is correct.  And I have a hard time believing that
> this would be different on HP-UX 11.xx.  Can you explain why you added
> this?

You are right, I shouldn't have added that. I thought this fixed a 
problem with signal frame unwinding when I was looking at 
hppa64-hp-hpux11.11, but actually I think something else is broken. 
Sorry for not testing this more thoroughly before committing. I'll back 
out that change tomorrow.

A few gcc bugs were making it a bit difficult for me to get good 
testsuite runs, but I think I have a good environment now that I can 
test hppa2.0w-hp-hpux11.11 and hppa64-hp-hpux11.11; I'll make sure I run 
the testsuite on these targets before I commit any other non-trivial 
hpux changes.

thanks for testing things out on hpux10.20... :)

randolph