Re: [libunwind] status of x86_64

[Arun Sharma]

George Lowe wrote:
> What is the current state of support for x86_64?
>
> I note that the most recent version is 0.98.5,
> from April 2005.  If I understand correctly,
> some patches for x86_64 have been proposed.
> I have the following additional questions:
>
>   What is the state of these patches?
>   How are they bundled?
>   Does one need to apply a series of patches,
>   or have the patches been collected into one
>   large patch?

They're currently in this mercurial repository.

http://www.serpentine.com/~arun/
http://www.serpentine.com/~arun/libunwind/releases/libunwind-0.98.6-test1.tar.gz

>   Will these patches be integrated into
>   the libunwind code?

davidm has reviewed most of them. There are a couple that are still 
under review.

>   Can the x86_64 version be built as a
>   static library to be used by a program
>   for introspective purposes?

Yes. I would suggest compiling them with libatomic ops, for better 
performance.

http://goog-perftools.sourceforge.net/

has a tool called pprof which does basically this.

>   Does the x86_64 version work with statically
>   linked programs?

Not yet. With glibc_2.3.3 we're a step closer (dl_iterate_phdr works for 
statically linked programs). But libunwind can't get to the .eh_frame 
section needed to get the dwarf unwinding information.

I'm trying to work out an interface with the gcc folks so libunwind can 
get to this info.

        -Arun