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Re: [libunwind] unwinding through dynamically modified code?
From: |
Todd L Miller |
Subject: |
Re: [libunwind] unwinding through dynamically modified code? |
Date: |
Wed, 24 Mar 2004 00:14:00 -0600 (CST) |
> Todd> code are the predicate registers (using UNW_DYN_SAVE_REG w/
> Todd> UNW_IA64_PR), ar.pfs (w/ UNW_IA64_AR_PFS), r1 (w/ UNW_IA64_GR
> Todd> + 1) and r12 (w/ UNW_IA64_GR + 12).
>
> Close, but not quite. The unwinder needs to know about:
So the unwinder does _not_ want/need to know about the predicate
registers and ar.pfs? (IIRC, some of the predicate registers are
preserved; I can't remember about ar.pfs; it may be a 'special' register.)
> The global-pointer (r1/gp) is a special case: it can be looked up via
> the instruction-pointer, so there is no need to describe it explicitly
> via unwind info.
That is to say that I should not have a _U_dyn_op_save_reg() for
r1? (Even though I preserve it.)
> If a save-location becomes invalid for any other reason, you'd have to
> describe that, of course, but in general, it would be better to follow
> the convention of keeping save-locations live.
OK. They never become invalid, but ... ah, if they never become
invalid, then libunwind can always find them there, even if they return to
their original locations.
> BTW: such things are better described in the Software Convention &
> Runtime Architecture guide.
Apparently you see more in it than I do. :)
Anyway, I will try to post a code fragment and the associated
libunwind calls tommorow, and then we can see how much of all this I've
actually absorbed.
- Todd Miller
- [libunwind] Re: multiple dynamic list-info addresses?, (continued)
- [libunwind] Re: multiple dynamic list-info addresses?, David Mosberger, 2004/03/29
- [libunwind] Re: multiple dynamic list-info addresses?, Todd L Miller, 2004/03/30
- [libunwind] Re: multiple dynamic list-info addresses?, David Mosberger, 2004/03/30
- [libunwind] Re: multiple dynamic list-info addresses?, Todd L Miller, 2004/03/31
- [libunwind] Re: multiple dynamic list-info addresses?, David Mosberger, 2004/03/31
- [libunwind] Re: multiple dynamic list-info addresses?, Todd L Miller, 2004/03/31
Re: [libunwind] unwinding through dynamically modified code?, Todd L Miller, 2004/03/23
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