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Re: [PATCH] Fix AMD64 backtrace

Jakub Jelinek <jakub@redhat.com> writes:

> On Sat, Jan 10, 2004 at 08:49:49PM +0100, Andreas Jaeger wrote:
>> Andreas Jaeger <aj@suse.de> writes:
>> 
>> > Jakub Jelinek <jakub@redhat.com> writes:
>> > [...]
>> >>> libc/sysdeps/x86_64/__longjmp.S
>> >
>> > What's the best way to handle the destroying of the registers with
>> > CFI?  Should we just mark the registers with "cfi_undefined"?
>> 
>> I'm appending a proposed patch for __longjmp.S.  Or can anybody
>> envision a better way doing this?
>
> Cannot you from the first movq ***,%rbx pretend you're
> already at the jmpq %*rdx instruction, ie. unwind to the
> longjmp target?
> Write in the unwind info where to fetch %rbp, %r12..%r15,
> ra etc. from?

You mean something like the following?

cfi_def_cfa(%rdi,0)
cfi_offset(%rbx,JB_RBX*8)
cfi_offset(%r12,JB_R12*8)
...

I'm not sure what the right way is to handle this here at all ...

Andreas
-- 
 Andreas Jaeger, aj@suse.de, http://www.suse.de/~aj
  SuSE Linux AG, Maxfeldstr. 5, 90409 Nürnberg, Germany
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