[RFC] fix for avr_skip_prologue()

[Theodore A. Roth]

On Sun, 4 Aug 2002, Andrew Cagney wrote:

>I don't think your change is any worse than many other *_skip_prologue() 
>tweaks.  A typical skip_prologue() function is an accumulation of 
>heuristics and a lot of comments.
>

<snip>

>> -      if (sal.line != 0 && sal.end < func_end)
>> +      /* troth/2002-70-19: For some very simple functions, gcc doesn't
>> +         generate a prologue and the sal.end ends up being the insn (2 bytes)
>> +         before func_end (the address of the next func). By adjusting
>> +         func_end, we can catch these functions and return the correct pc. */
>
>I'd just also mention that the instruction in question is ``return'' and 
>is two bytes long.

Let's see if I understand what you are saying here. It looks like sal.end 
becomes the ``return'' instruction which is 1 insn (2 bytes) before 
func_end. If so, it might make more sense for the patch to be 

+      if (sal.line != 0 && (sal.end+2) < func_end)

Thus if sal.end is the ``return'' insn for the simple function, we just
return the current pc instead of sal.end.

If that makes any sense to you, I'll fix the comment and commit it.

Ted Roth