ping: two proposals about frame unwind in RS6K, specifically in Linux

[Wu Zhou <woodzltc at cn dot ibm dot com>]

I ever posted two proposals about frame unwind in RS6000. The first one is at:

http://sources.redhat.com/ml/gdb/2006-10/msg00085.html

which don't skip the prologue when the instruction is bl and the  
target is blrl. I coded a patch based on Joel's initial patch and also  
take Daniel's comment into consideration.  It can fix my problems.   
The original post also said that it brought some modification to the  
test result of gdb's testsuite.  My latest investigation shows that  
there is no regression. So I believe this proposal is ok principally.

The second one is at:

http://sources.redhat.com/ml/gdb/2006-10/msg00276.html

which propose to assume the underlying program will comply to the ABI  
when there is no cfi directive, prologue analysis won't find any  
prologue instructions and current context doesn't not belong to any  
special cases which won't comply to ABI.  I coded a proof-of-concept  
patch, which can fix my problem in quite some case and don't bring  
much problem. So I also think that this is feasible.

Anyone would like to take a look at these?  If there are any errors,  
please feel free to correct and educate me.  Thanks a lot!

Regards
- Wu Zhou