Re: [RFC 1/3] [gdb] Call gdbarch_get_syscall_number less often

[Simon Marchi <simark@simark.ca>]

On 11/21/23 13:03, John Baldwin wrote:
> I think you can use linux_nat_target::set_syscall_catchpoint to do the
> invalidation.  From my reading it is called each time a syscall catchpoint
> is added or removed, and needed is set to false if there are no more
> catchpoints (so syscall catches are disabled).   I think that means
> you could do something like:
> 
> linux_nat_target::set_syscall_catchpoint ()
> {
>   if (!needed)
>     iterate_over_lwps (ptid_t (pid), [] (struct lwp_info *lp)
>                        {
>                          lp->syscall_number = -1;
>                        });
> }

What about this corner case of a corner case:

 1. you have a syscall catchpoint, you hit it (the syscall entry)
 2. you delete the syscall catchpoint
 3. you create a syscall catchpoint again
 4. you continue, expecting to hit the syscall exit

Will step 2 cause set_syscall_catchpoint to be called, and will we
therefore lose the information that would have been useful at step 4?

Simon