Re: [Libunwind-devel] Multi-platform unwinding i386 binary on x86_64 bugs and patch.

[Andrew Cagney]

Arun Sharma wrote:
> On 5/2/07, *Andrew Cagney* <address@hidden 
> <mailto:address@hidden>> wrote:
>
>     Arun,
>
>     We have multi-platform, or remote, unwinding working.  For instance,
>     x86-64 backtracing an i386, or even a 32-bit PowerPC unwinding an
>     x86-64.  That is cool, way cool, something to celebrate!   We've
>     finally
>     got this out of the "left as an exercise for the reader" bucket :-)
>     With this functionality working becomes possible to do cool stuff such
>     as display backtraces of a process as it alternatively exec's
>     32-bit and
>     then 64-bit programs.
>
>
>
> Indeed. When you did this, I suppose you wrote your own accessors to  
> get to  the memory of the  remote process whose stack is being unwound?

Yes, that is what Nurdin noted earlier.

>     Our challenges now are:
>
>     - get frysk's existing local fixes to libunwind finally merged

Here, I'm referring to the other patches previously posted but not 
reviewed.  Perhaps we can work on that backlog?


> To me Gget_unwind_table.c seems to be doing something different from 
> _UPT*. So I don't see why
>
> libunwind/src/ptrace/_UPT_find_proc_info.c
>
> should be patched. But if your goal is to get something like 
> Gget_unwind_table.c into libunwind, so remote unwinding would work out 
> of the box for many common cases, that would be a separate patchset.
>
> I think David still should be the primary reviewer for that. I'd be 
> happy to review any x86/x86_64 specific bits.

I look forward to this.

Andrew