Re: "Debugging stubs for supporting tracepoint"

[Ramana Radhakrishnan <ramana dot radhakrishnan at codito dot com>]

Hi,


> Hi
> 
> 
> 
> Hi 
> 
>   The following is except from doc., "Debugging with GDB":
> 
> ____________________________________________________________ 
> The tracepoint facility is currently available only for remote targets. 
> See Chapter 16[Targets], page 143. In addition, your remote target 
> must know how to collect trace data. This functionality is implemented
> in the remote stub; however, none of the stubs distributed
> with gdb support tracepoints as of this writing.
> This chapter describes the tracepoint commands and features.
> ------------------------------------------------------------------
> 
>   Then question is where to get start if one wants to implement
> tracepoint support on remote stubs?

In the remote stub, you would need the stub to collect data per
tracepoint whenever it is hit. Right , so what are tracepoints ? 

Tracepoints can be thought of to be equivalent to software breakpoints
from an implementation point of view and the commands / actions need to
be executed at the time the tracepoint is hit . So in your stub you
would determine whether a breakpoint or a tracepoint has been hit when
the inferior stops and then store the data needed in whatever format
needed.

 (Commands / Actions which have been specified for the tracepoints about
which you can find info in the Agent Expression chapter in the manual /
ax-gdb.c in the source tree.) . The mailing list archives could give you
some idea regarding the same also. AFAIK none of the existing stubs in
the source tree support them. 

cheers
ramana