Re: [rfa/mips] Stop backtraces when we've lost the PC

[Andrew Cagney <cagney@gnu.org>]

>  	{
>  	  int low, mid, high;
>  	  char *ptr;
> +	  CORE_ADDR pdr_pc;
>  
>  	  low = 0;
>  	  high = priv->size / 32;
>  
> +	  /* First, find the last .pdr entry starting at or before PC.  */

A summary here of what the objective is and what / why the follow on 
code is doing.

>  	  do
>  	    {
> -	      CORE_ADDR pdr_pc;
> -
>  	      mid = (low + high) / 2;
>  
>  	      ptr = priv->contents + mid * 32;
>  	      pdr_pc = bfd_get_signed_32 (sec->objfile->obfd, ptr);
>  	      pdr_pc += ANOFFSET (sec->objfile->section_offsets,
>  				  SECT_OFF_TEXT (sec->objfile));

> -	      if (pdr_pc == startaddr)
> +	      if (pdr_pc == pc)
>  		break;

> -	      if (pdr_pc > startaddr)
> +	      if (pdr_pc > pc)
>  		high = mid;
>  	      else
>  		low = mid + 1;

>  	    }

>  	  while (low != high);

Other than that, just an observation that the binary search is [already] 
pretty messed up.  In all likelyhood the test:

	if (pdr_pc == pc)

will never fire and having it gains little if anything (one less 
iteration VS logN extra compares).  Eliminating it means cleaning up the 
binary search though.   Can you attach a fixme to that test indicating 
that it should be eliminated.

I also suspect that STARTADDR's computation can be delayed until it is 
needed (the latter reference that goes with the "pathological", should 
no longer occure, I think it has been moved into symbol reading. 
However, leave that for the moment.

Otherwize ok, and way better than the original patch, thanks,

Andrew