This patch adds support for trace files, which are simply dumps of a 
target's tracepoints and trace buffer.  In addition to the new "tsave" 
command to create a trace file, there is a new target "tfile" that opens 
a trace file and then lets you do tfind and then print any data that was 
collected, just as for you would do for a live target.

I apologize in advance for the size of this patch; while about half of 
it is simply the new code that does all the file reading and writing, 
the other half is needed to rework the uploading machinery that was 
introduced for disconnected tracing, so we can do the same kind of 
parsing for tracepoint definitions, whether they come from a file or a 
live target.  This patch also includes an expansion of tstatus, again 
with shared parsing between file and remote, that can display useful 
details like trace buffer usage and the reason for a trace run having 
stopped.  Despite the size, the changes are all confined to tracing.

Originally I thought this was going to be untestable until we got 
gdbserver patches in - while in theory one could make up some generic 
trace files and add them to testsuite, it's hard to make all the 
addresses and such line up correctly and in an arch-independent way.  
But it's occurred to me that a test program could itself manually 
construct a trace file, simply taking the addresses of its own variables 
to set up useful memory blocks, and so I'm giving that a try.  In the 
meantime please give this patch a once-over, point out anything that 
seems missing.

Stan

2010-01-11  Stan Shebs  <stan@codesourcery.com>

    Add trace file support.
    * tracepoint.h (enum trace_stop_reason): New enum.
    (struct trace_status): New struct.
    (parse_trace_status): Declare.
    (struct uploaded_tp): Move here from remote.c,
    add fields for actions.
    (struct uploaded_tsv): New struct.
    * tracepoint.c (tfile_ops): New target vector.
    (trace_fd): New global.
    (tfile_open): New function.
    (tfile_close): New function.
    (tfile_files_info): New function.
    (tfile_get_trace_status): New function.
    (tfile_get_traceframe_address): New function.
    (tfile_trace_find): New function.
    (tfile_fetch_registers): New function.
    (tfile_xfer_partial): New function.
    (tfile_get_trace_state_variable_value): New function.
    (init_tfile_ops): New function.
    (_initialize_tracepoint): Call it, add tfile target.
    (trace_status): New global.
    (current_trace_status): New function.
    (trace_running_p): Remove, change all users to get from
    current_trace_status()->running.
    (get_trace_status): Remove.
    (trace_status_command): Call target_get_trace_status directly,
    report more detail including tracing stop reasons.
    (trace_find_command): Always allow tfind on a file.
    (trace_find_pc_command): Ditto.
    (trace_find_tracepoint_command): Ditto.
    (trace_find_line_command): Ditto.
    (trace_find_range_command): Ditto.
    (trace_find_outside_command): Ditto.
    (trace_frames_offset, cur_offset): Declare as off_t.
    (trace_regblock_size): Rename from reg_size, update users.
    (parse_trace_status): New function.
    (tfile_interp_line): New function.
    (disconnect_or_stop_tracing): Ensure current trace
    status before asking what to do.
    (stop_reason_names): New global.
    (trace_save_command): New command.
    (get_uploaded_tp): Move here from remote.c.
    (find_matching_tracepoint): Ditto.
    (merge_uploaded_tracepoints): New function.
    (parse_trace_status): Use stop_reason_names.
    (_initialize_tracepoint): Define tsave command.
    * target.h (target_ops): New fields to_save_trace_data,
    to_upload_tracepoints, to_upload_trace_state_variables,
    to_get_raw_trace_data, change to_get_trace_status
    to take a pointer to a status struct.
    (target_save_trace_data): New macro.
    (target_upload_tracepoints): New macro.
    (target_upload_trace_state_variables): New macro.
    (target_get_raw_trace_data): New macro.
    * target.c (update_current_target): Add new methods, change
    signature of to_get_trace_status.
    * remote.c (hex2bin): Make globally visible.
    (bin2hex): Ditto.
    (remote_download_trace_state_variable): Download name also.
    (remote_get_trace_status): Update parameter, use
    parse_trace_status.
    (remote_save_trace_data): New function.
    (remote_upload_tracepoints): New function.
    (remote_upload_trace_state_variables): New function.
    (remote_get_raw_trace_data): New function.
    (remote_start_remote): Use them.
    (_initialize_remote_ops): Add operations.
    * ax-gdb.c: Include breakpoint.h.
    * breakpoint.c (create_tracepoint_from_upload): Use
    break_command_really, return tracepoint, warn about unimplemented
    parts.

    * gdb.texinfo (Trace Files): New section.
    (Tracepoint Packets): Document QTSave and qTBuffer.