Re: MI: reporting of multiple breakpoints

Daniel Jacobowitz
2006-02-17T22:12:39Z

On Fri, Feb 17, 2006 at 04:56:45PM -0500, Paul Koning wrote:
> However, the fact that some architectures have imprecise watchpoints
> is no reason to force imprecision on those that can do better. In
> other words, this should be an example of target-dependent machinery:
> if the target has the ability to determine the "PC of the watchpoint
> trigger instruction" then it should do so, and the break/watch display
> reporting machinery should use that information to report the
> watchpoint at the "correct" source line.

I am not familiar with any hardware watchpoint implementation (onboard
registers, JTAG, whatever) that can supply "PC of the watchpoint
trigger instruction" usefully. But I'm not familiar with a whole heck
of a lot of those, so...

Page table based watchpoints obviously could do this.

On architectures with fixed size instructions and precise watchpoints
and no delay slots, maybe you can get away with a subtraction, but I'm
not at all sure about that. Hum, it looks like MIPS WatchHi/WatchLo
can actually point to the instruction itself.

But now we're off into wishlist land, I'm afraid.

--
Daniel Jacobowitz
CodeSourcery