[PATCH , all targets] Fix order of prologue instructions for varargs functions with -O0 and -m32

[Dave Korn]

Daniel Jacobowitz wrote:
> On Sat, Feb 28, 2009 at 10:46:50AM +0000, Dave Korn wrote:
>>> 2 - GDB stops right after the branch, due to an additional line number
>>> entry that is (forcibly) generated because GCC saw a different Basic
>>> Block.
>>   Ah.  I wonder if there's an implicit assumption in GDB that the prologue is
>> only a single basic block?
> 
> Irrelevant, but it has to be a single "line".  That's how prologue
> analysis has worked in GDB for probably 20 years.  It's improved a lot
> in that time, but the basic assumption remains.
> 
>>   Hmm, but shouldn't GDB really be paying attention to the information it
>> receives from RTX_FRAME_RELATED_P?
> 
> GDB does not receive this information.
> 

  Ok, so I guess Luis' suggestion:

Luis Machado wrote:

> The other way around this problem, without changing the ordering of
> instructions in more general code is to omit the output of that
> additional Line Number Entry. Does it sound like a better solution for
> mainline?

... must be the right thing to do.

    cheers,
      DaveK