DWARF-2 unwinder versus MIPS n32

[David Daney]

David Daney wrote:
> Daniel Jacobowitz wrote:
>> I'm trying to track down why unwinding through a signal frame crashes
>> on MIPS n32.  David, I'm pretty sure you introduced the crash here:
>>
>> 2006-11-20  David Daney  <ddaney@avtrex.com>
>>
>>         * config/mips/linux-unwind.h (mips_fallback_frame_state): Adjust
>>         PC to point to following instruction.
>>
> 
> I don't doubt that there are problems here.  I was going to clean up the 
> compiler warnings that are now generated in that code, but it looks like 
> more major work is needed.
> 

I might add that something like this patch is required.  The PC must be 
incremented so that proper unwinding is obtained if the fault occurs on 
the first instruction of a function.

Before this patch there was a special o32 only hack in libgcj that 
adjusted the value of the PC in the sigcontext saved on the stack before 
calling the unwinder.  The idea was to place all the code needed to 
unwind through signal frames into MD_FALLBACK_FRAME_STATE_FOR.

David Daney