On 10/4/11 12:10 PM, Tom Tromey wrote:
>>>>>> "Stan" == Stan Shebs<stan_shebs@mentor.com>  writes:
> Stan>  While conceptually simple, we need a new agent bytecode to make this
> Stan>  work (writing a loop using existing bytecodes doesn't let us check
> Stan>  that we're running off the edge of valid memory), and a support flag
> Stan>  so that users get informed if the target doesn't support string
> Stan>  collection.
>
> Stan>  + /* Inspired by trace_kludge, this indicates that pointers to chars
> Stan>  +    should get an added tracenz bytecode to record nonzero bytes, up to
> Stan>  +    a length that is the value of string_kludge.  */
> Stan>  + int string_kludge;
>
> I'd prefer a name that makes it obvious that this is a tracing thing.
>
> Stan>  +   { "tracenz", PACKET_DISABLE,
> Stan>  +     remote_string_tracing_feature, -1 },
>
> I think this requires documentation in the remote protocol section.
>
> Stan>  +   while (*exp == ' ' || *exp == '\t')
> Stan>  +     exp++;
>
> We have skip_spaces now.
>
>

Thanks for the feedback!  I took all into account, and committed this:

2011-11-02  Stan Shebs <stan@codesourcery.com>

     String collection for tracepoints.
     * NEWS: Mention string collection.
     * common/ax.def (tracenz): New bytecode.
     * ax-gdb.h (trace_string_kludge): Declare.
     * ax-gdb.c: Include valprint.h and c-lang.h.
     (trace_string_kludge): New global.
     (gen_traced_pop): Add string case.
     (agent_command): Add string case.
     * tracepoint.h (decode_agent_options): Declare.
     * tracepoint.c: Include cli-utils.h.
     (decode_agent_options): New function.
     (validate_actionline): Call it.
     (encode_actions_1): Ditto.
     * target.h (struct target_ops): New method to_supports_string_tracing.
     (target_supports_string_tracing): New macro.
     * target.c (update_current_target): Add to_supports_string_tracing.
     * remote.c (struct remote_state): New field string_tracing.
     (remote_string_tracing_feature): New function.
     (remote_protocol_features): New feature tracenz.
     (remote_supports_string_tracing): New function.
     (init_remote_ops): Set to_supports_string_tracing.

     * tracepoint.c (agent_mem_read_string): New function.
     (eval_agent_expr): Call it for tracenz.
     * server.c (handle_query): Report support for tracenz.

     * gdb.texinfo (Tracepoint Action Lists): Document collect/s.
     (General Query Packets): Describe tracenz feature.
     * agentexpr.texi (Bytecode Descriptions): Describe tracenz.

     * gdb.trace/collection.c: Add code using strings.
     * gdb.trace/collection.exp: Add tests of string collection.