For several RSP packets, there's a corresponding "set remote
foo-packet on/off/auto" command that one can use do bypass
auto-detection of support for the packet or feature. However, I
noticed that setting several of these commands to 'on' or 'off'
doesn't actually have any effect. These are, at least:
set remote breakpoint-commands-packet
set remote conditional-breakpoints-packet
set remote fast-tracepoints-packet
set remote static-tracepoints-packet
set remote install-in-trace-packet
These are commands that control a remote protocol feature that doesn't
have a corresponding regular packet, and because of that we cache the
knowledge of the remote side support as returned by the qSupported
packet in the remote_state object.
E.g., in the case of the 'set remote breakpoint-commands-packet'
command, whether the feature is supported is recorded in the
'breakpoint_commands' field of the remote_state object.
Whether to bypass packet support auto-detection or not is controlled
by the 'detect' field of the corresponding packet's packet_config
structure. That field is the variable associated directly with the
"set remote foo-packet" command. Actual remote stub support for the
packet (or feature) is recorded in the 'support' field of the same
structure.
However, when the user toggles the command, the 'support' field is
also correspondingly updated to PACKET_ENABLE/DISABLE/SUPPORT_UNKNOWN,
discarding the knowledge of whether the target actually supports the
feature. If one toggles back to 'auto', it's no big issue for real
packets, as they'll just end up re-probed the next time they might be
necessary. But features whose support is only reported through
qSupported don't get their corresponding (manually added/maintained)
fields in remote_state objected updated. As we lost the actual status
of the target support for the feature, GDB would need to probe the
qSupported features again, which GDB doesn't do.
But we can avoid that extra traffic, and clean things up, IMO.
Instead of going in that direction, this patch completely decouples
struct packet_config's 'detect' and 'support' fields. E.g., when the
user does "set remote foo-packet off", instead of setting the packet
config's 'support' field to PACKET_DISABLE, the 'support' field is not
touched at all anymore. That is, we end up respecting this simple
table:
| packet_config->detect | packet_config->support | should use packet/feature? |
|-----------------------+------------------------+----------------------------|
| auto | PACKET_ENABLE | PACKET_ENABLE |
| auto | PACKET_DISABLE | PACKET_DISABLE |
| auto | PACKET_UNKNOWN | PACKET_UNKNOWN |
| yes | don't care | PACKET_ENABLE |
| no | don't care | PACKET_DISABLE |
This is implemented by the new packet_support function. With that, we
need to update this pattern throughout:
if (remote_protocol_packets[PACKET_foo].support == PACKET_DISABLE)
to do this instead:
if (packet_support (PACKET_qAttached) == PACKET_DISABLE)
where as mentioned, the packet_support function takes struct
packet_config's 'detect' field into account, like in the table above.
As when the packet is force-disabled or force-enabled, the 'support'
field is just ignored, if the command is set back to auto, we'll
resume respecting whatever the target said it supports. IOW, the end
result is that the 'support' field always represents whether the
target actually supports the packet or not.
After all that, the manually maintained breakpoint_commands and
equivalent fields of struct remote_state can then be eliminated, with
references replaced by checking the result of calling the
packet_support function on the corresponding packet or feature. This
required adding new PACKET_foo enum values for several features that
didn't have it yet. (The patch does not add corresponding "set remote
foo-packet" style commands though, focusing only on bug fixing and
laying the groundwork).
Tested on x86_64 Fedora 17, native GDBserver. The new tests all fail
without this patch.
gdb/
2014-04-25 Pedro Alves <palves@redhat.com>
* remote.c (struct remote_state): Remove multi_process_aware,
non_stop_aware, cond_tracepoints, cond_breakpoints,
breakpoint_commands, fast_tracepoints, static_tracepoints,
install_in_trace, disconnected_tracing,
enable_disable_tracepoints, string_tracing, and
augmented_libraries_svr4_read fields.
(remote_multi_process_p): Move further below in the file.
(struct packet_config): Add comments.
(update_packet_config): Delete function.
(show_packet_config_cmd): Use packet_config_support.
(add_packet_config_cmd): Use NULL as set callback.
(packet_ok): "set remote foo-packet"-style commands no longer
change config->supported -- adjust.
(PACKET_ConditionalTracepoints, PACKET_ConditionalBreakpoints)
(PACKET_BreakpointCommands, PACKET_FastTracepoints)
(PACKET_StaticTracepoints, PACKET_InstallInTrace): Add comments.
(PACKET_QNonStop, PACKET_multiprocess_feature)
(PACKET_EnableDisableTracepoints_feature, PACKET_tracenz_feature)
(PACKET_DisconnectedTracing_feature)
(PACKET_augmented_libraries_svr4_read_feature): New enum values.
(set_remote_protocol_packet_cmd): Delete function.
(packet_config_support, packet_support): New functions.
(set_remote_protocol_Z_packet_cmd): Don't call
update_packet_config.
(remote_query_attached, remote_pass_signals)
(remote_program_signals, remote_threads_info)
(remote_threads_extra_info, remote_start_remote): Use
packet_support.
(remote_start_remote): Use packet_config_support and
packet_support.
(init_all_packet_configs): Set all packets to unknown support,
instead of calling update_packet_config.
(remote_check_symbols): Use packet_support.
(remote_supported_packet): Unconditionally set the packet config's
support status.
(remote_multi_process_feature, remote_non_stop_feature)
(remote_cond_tracepoint_feature, remote_cond_breakpoint_feature)
(remote_breakpoint_commands_feature)
(remote_fast_tracepoint_feature, remote_static_tracepoint_feature)
(remote_install_in_trace_feature)
(remote_disconnected_tracing_feature)
(remote_enable_disable_tracepoint_feature)
(remote_string_tracing_feature)
(remote_augmented_libraries_svr4_read_feature): Delete functions.
(remote_protocol_features): Adjust to use remote_supported_packet
for "augmented-libraries-svr4-read", "multiprocess", "QNonStop",
"ConditionalTracepoints", "ConditionalBreakpoints",
"BreakpointCommands", "FastTracepoints", "StaticTracepoints",
"InstallInTrace", "DisconnectedTracing", "DisconnectedTracing",
"EnableDisableTracepoints", and "tracenz".
(remote_query_supported): Use packet_support.
(remote_open_1): Adjust.
(extended_remote_attach_1): Use packet_support. Switch on the
result of packet_ok instead of checking whether the packet ended
up disabled.
(remote_vcont_resume): Use packet_support.
(remote_resume, remote_stop_ns, fetch_register_using_p)
(remote_prepare_to_store, store_register_using_P)
(check_binary_download, remote_write_bytes): Use packet_support.
(remote_vkill): Use packet_support. Switch on the result of
packet_ok instead of checking whether the packet ended up
disabled.
(extended_remote_supports_disable_randomization): Use
packet_support.
(extended_remote_run): Switch on the result of packet_ok instead
of checking whether the packet ended up disabled.
(remote_insert_breakpoint, remote_remove_breakpoint)
(remote_insert_watchpoint, remote_remove_watchpoint)
(remote_insert_hw_breakpoint, remote_remove_hw_breakpoint): Use
packet_support.
(remote_search_memory): Use packet_config_support.
(remote_get_thread_local_address, remote_get_tib_address)
(remote_hostio_send_command, remote_can_execute_reverse): Use
packet_support.
(remote_supports_cond_tracepoints)
(remote_supports_cond_breakpoints)
(remote_supports_fast_tracepoints)
(remote_supports_static_tracepoints)
(remote_supports_install_in_trace)
(remote_supports_enable_disable_tracepoint)
(remote_supports_string_tracing)
(remote_can_run_breakpoint_commands): Rewrite, checking whether
the packet config says the feature is enabled or disabled.
(remote_download_tracepoint, remote_trace_set_readonly_regions)
(remote_get_trace_status): Use packet_support.
(remote_set_disconnected_tracing): Adjust to check whether the
feature is enabled with packet_support.
(remote_set_trace_buffer_size, remote_use_agent)
(remote_can_use_agent, remote_supports_btrace): Use
packet_support.
(remote_enable_btrace, remote_disable_btrace, remote_read_btrace):
Use packet_config_support.
(remote_augmented_libraries_svr4_read): Rewrite, checking whether
the packet config says the feature is enabled or disabled.
(set_range_stepping): Use packet_support.
gdb/testsuite/
2014-04-25 Pedro Alves <palves@redhat.com>
* gdb.base/cond-eval-mode.exp (warning): Move trailing \r\n to
user.
(top level): Test that "set remote conditional-breakpoints-packet
off" works as intended.
* gdb.base/dprintf.exp: Test that "set remote
breakpoint-commands-packet off" works as intended.
* gdb.trace/change-loc.exp (tracepoint_install_in_trace_disabled):
New function.
(top level): Call it.
* gdb.trace/ftrace.exp (test_fast_tracepoints): Test that "set
remote fast-tracepoints-packet off" works as intended.
* gdb.trace/qtro.exp (gdb_is_target_remote): Moved ...
* lib/gdb.exp (gdb_is_target_remote): ... here.
As we move code on reading unavailable memory to target side, GDB core
side doesn't need the "switching momentarily out of tfind mode" dance.
The target remote knows how to read live memory (through remote_ops).
Remove set_traceframe_number and
make_cleanup_restore_traceframe_number, since they are no longer used.
gdb:
2014-03-22 Yao Qi <yao@codesourcery.com>
* remote.c (target_read_live_memory): Remove.
(memory_xfer_live_readonly_partial): Rename it to
remote_xfer_live_readonly_partial. Remove argument 'object'.
All callers updated. Call remote_read_bytes_1
instead of target_read_live_memory.
* tracepoint.c (set_traceframe_number): Remove.
(make_cleanup_restore_traceframe_number): Likewise .
* tracepoint.h (set_traceframe_number): Remove declaration.
(make_cleanup_restore_traceframe_number): Likewise.
This patch moves code in remote_read_bytes on reading from the remote
stub to a new function remote_read_bytes_1.
gdb:
2014-03-22 Yao Qi <yao@codesourcery.com>
* remote.c (remote_read_bytes): Move code on reading from the
remote stub to ...
(remote_read_bytes_1): ... here. New function.
As a follow-up to
[PATCH 7/8] Adjust read_value_memory to use to_xfer_partial
https://sourceware.org/ml/gdb-patches/2014-02/msg00384.html
this patch moves traceframe_available_memory down to the target side.
After this patch, the gdb core code is cleaner, and code on handling
unavailable memory is moved to remote/tfile/ctf targets.
In details, this patch moves traceframe_available_memory code from
memory_xfer_partial_1 to remote target only, so remote target still
uses traceframe_info mechanism to check unavailable memory, and use
remote_ops to read them from read-only sections. We don't use
traceframe_info mechanism for tfile and ctf target, because it is
fast to iterate all traceframes from trace file, so the summary
information got from traceframe_info is not necessary.
This patch also moves two functions to remote.c from target.c,
because they are only used in remote.c. I'll clean them up in another
patch.
gdb:
2014-03-22 Yao Qi <yao@codesourcery.com>
* ctf.c (ctf_xfer_partial): Check the return value of
exec_read_partial_read_only, if it is not TARGET_XFER_OK,
return TARGET_XFER_UNAVAILABLE.
* tracefile-tfile.c (tfile_xfer_partial): Likewise.
* target.c (target_read_live_memory): Move it to remote.c.
(memory_xfer_live_readonly_partial): Likewise.
(memory_xfer_partial_1): Move some code to remote_read_bytes.
* remote.c (target_read_live_memory): Moved from target.c.
(memory_xfer_live_readonly_partial): Likewise.
(remote_read_bytes): New, factored out from
memory_xfer_partial_1.
As we migrate to the new to_xfer_partial interface, some of previous
tweaks become unnecessary, we don't have to check traceframe is
selected in each target implementation, so this patch below is
reverted.
[PATCH] Send qXfer:traceframe-info:read when traceframe is selected.
https://sourceware.org/ml/gdb-patches/2013-10/msg00752.html
Third, to_traceframe_info is only called when traceframe is selected,
that means it is only called when target is remote, tfile or ctf, so
this patch can be partially reverted,
https://sourceware.org/ml/gdb-patches/2013-04/msg00000.html
gdb:
2014-02-23 Yao Qi <yao@codesourcery.com>
Revert two patches:
2013-10-25 Yao Qi <yao@codesourcery.com>
* remote.c (remote_traceframe_info): Return early if
traceframe is not selected.
2013-07-19 Yao Qi <yao@codesourcery.com>
* target.c (update_current_target): Change the default action
of 'to_traceframe_info' from tcomplain to return_zero.
* target.h (struct target_ops) <to_traceframe_info>: Add more
comments.
From GDB's perspective, independently of how the target really
implements threads, gdb/remote sees all threads as if kernel/system
threads. A rationale along theses lines led to gdbserver storing
thread ids in ptid.lwp in all ports.
Because remote.c is currently using ptid.tid, we can't make gdbserver
and gdb share bits of remote-specific code that manipulates ptids
(e.g., write_ptid/read_ptid).
This patch thus makes remote.c use ptid.lwp instead of ptid.tid.
I believe that on the GDB side too, it's best that we standardize on
process_stratum targets using the ptid.lwp field to store thread ids
anyway. The idea being leave the ptid.tid field free for any
thread_stratum target that might want to sit on top.
Tested on x86_64 Fedora 17, w/ local gdbserver.
gdb/
2014-02-19 Pedro Alves <palves@redhat.com>
* remote.c (remote_thread_alive, write_ptid, read_ptid)
(read_ptid, remote_newthread_step, remote_threads_extra_info)
(remote_get_ada_task_ptid, append_resumption, remote_stop_ns)
(threadalive_test, remote_pid_to_str): Use the ptid.lwp field to
store remote thread ids rather than ptid.tid.
(_initialize_remote): Adjust.
This switches to_read_description to the "new normal" delegation
scheme. This one was a bit trickier than the other changes due to the
way that target_read_description handled delegation. I examined all
the target implementations of to_read_description and changed the ones
returning NULL to instead delegate.
2014-02-19 Tom Tromey <tromey@redhat.com>
* arm-linux-nat.c (arm_linux_read_description): Delegate when
needed.
* corelow.c (core_read_description): Delegate when needed.
* remote.c (remote_read_description): Delegate when needed.
* target-delegates.c: Rebuild.
* target.c (target_read_description): Rewrite.
* target.h (struct target_ops) <to_read_description>: Update
comment. Use TARGET_DEFAULT_RETURN.
