Re: [RFC] TARGET_ADJUST_BREAKPOINT_ADDRESS - patch 1 of 4

Andrew Cagney
2003-10-11T16:17:07Z

> On Oct 8, 2:26pm, Andrew Cagney wrote:
>
>
>> I also wonder if PPC64 GDB could use this to do the descriptor ->
>> function address transformation that I described in:
>> http://sources.redhat.com/ml/gdb-patches/2003-09/msg00415.html
>
>
> I suppose it could, although that's definitely not the (well, my)
> intended purpose of ADJUST_BREAKPOINT_ADDRESS. If we do wind up using
> it for this purpose, we'll want to disable the warning messages. It
> makes no sense to have a breakpoint on the descriptor, so when used in
> this way, it'd definitely be the case that gdb is just doing the
> "right thing". It'd be easy enough to add an argument to the method
> which passes indicating the kind of adjustment. Off hand, I think a
> tri-state value makes sense:

right.

> 1) the adjustment can potentially alter expected behavior making
> user warnings manditory. E.g, FR-V architecture constraints.
>
> 2) benign, the breakpoint's location has been moved slightly,
> but there should be no change in expected behavior. Perhaps
> an informational message could be displayed for this state.
> E.g. - maybe - that old v850 problem that Gary Thomas once
> told us about in which he had to sometimes place breakpoints
> that were larger than the smallest instruction.
>
> 3) the adjustment was necessary because to place a breakpoint on
> the original address is wrong. E.g, function descriptors -
> it makes no sense to place a breakpoint on the function descriptor,
> but it does make sense to place a breakpoint on the code address
> that the descriptor points to.

or:

if (the architecture can adjust things)
adjust
if (the architecture thinks the adjustment is weird)
warning

A follow-on change can refine it.

Andrew