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Re: [PATCH] i386_skip_prologue.
On Sat, Dec 30, 2006 at 10:20:52PM +0100, Mark Kettenis wrote:
> I'm sorry. I tend to suffer from packet loss at my side.
No problem - that's what I'm here for :-)
> > Is there a general philosophy we could adopt that would apply to most
> > or all targets?
> >
> > Here's a proposal to get us started: when skipping the prologue to
> > place a breakpoint or finish single stepping (skip_prologue), try to
> > skip to the end of the first sal. But some targets may optionally run
> > their prologue analyzer and make sure it doesn't see anything it
> > objects to - like jumps. That would mean the i386 prologue analyzer
> > would need to know about this new call to __main. When scanning the
> > prologue to build frame unwind information, ignore sals entirely.
> > Scan until we hit the saved PC or until we believe we understand
> > the entire frame.
>
> The last time I tried using sals on i386, I simply encountered too
> many cases where the line number information couldn't be trusted and
> putting a breakpoint on a function that was defenitely called never
> hit.
Yeah. That's definitely the biggest risk.
I think the first step, for Pedro's specific problem, should be
to recognize the call to __main as special and skippable. We can
play with sals later.
--
Daniel Jacobowitz
CodeSourcery