:ADDPATCH PowerPC-64:

Hi,

Bringing back this topic, i've written a patch to address this issue on
ppc's side, providing a function to specify call-clobbered registers
based on the ABI, similar to the S390's.

Looking forward to suggestions/corrections.

Best regards


> There is simply not enough information in the debug info to handle
> this correctly.  Let me give you another example:
> 
>      move var to r3
>      test something
>      if true, branch to Lfoo
>      call abort, which clobbers r3
> Lfoo:
>      do something with r3
> 
> At every instruction after the move, the debug info should say that
> var is in r3.  Right?  No matter which location we pick here, while
> backtracing from abort, we'll print the wrong value for var and
> there's no point where the debug info will say it is undefined.
> 
> If you want us to get this right using DWARF info, I believe your only
> choice is to approach the DWARF working group about it.
> 
> Now, in GDB we may have other options.  We might be able to get the
> list of call clobbered registers based on the ABI.  Compare with s390,
> which already does this (dwarf2_frame_set_init_reg).  Does adding
> this to PowerPC help your example any?
> 
-- 
Luis Machado
IBM Linux Technology Center
e-mail: luisgpm@linux.vnet.ibm.com