Re: [RFC] stepping over permanent breakpoint

[Aleksandar Ristovski <aristovski@qnx.com>]

Pedro Alves wrote:
> 
> Not all architectures that run linux need PC adjustment.  You're
> thinking x86-linux.  Anyway, I meant that you're breaking setting
> a user breakpoint on top of a permanent breakpoint.  Try
> setting a breakpoint with "break *int3_addr", on top
> of that int3, and running to it.  When it is hit, you're moving
> the PC passed it, so later calls to bpstat_stop_status like:
> 
>       /* See if there is a breakpoint at the current PC.  */
>       ecs->event_thread->stop_bpstat = bpstat_stop_status (stop_pc, ecs->ptid);
> 
> ... will not see the permanent breakpoint, right?


Hmm... very interesting. I am not seeing what you suggest 
(it works for me) but by looking at the code, I don't 
understand why - I agree it should be broken as you say, but 
for some reason it isn't. I will have to look into this a 
bit more (I am working in gdb 6.7).


> 
> Mark's point about considering a trap instruction as a normal
> instruction is valid, so I'm not sure if we'd want to do this
> skipping by default or not.  I'll let you guys fight
> over it.  :-)
> 

Other than wanting to make gdb on qnx work, I have no strong 
feelings about one way or the other... It was a thought.