This fixes a gdb.base/multi-forks.exp regression with GDBserver.
Git commit f2ffa92bbc ("gdb: Eliminate the 'stop_pc' global") caused
the regression by exposing a latent bug in gdbserver.
The bug is that GDBserver's implementation of the D;PID packet
incorrectly assumes that the selected thread points to the process
being detached. This happens via the any_persistent_commands call,
which calls current_process:
(gdb) bt
#0 0x000000000040a57e in internal_error(char const*, int, char const*, ...)
(file=0x4a53c0 "src/gdb/gdbserver/inferiors.c", line=212, fmt=0x4a539e "%s:
Assertion `%s' failed.") at src/gdb/gdbserver/../common/errors.c:54
#1 0x0000000000420acf in current_process() () at
src/gdb/gdbserver/inferiors.c:212
#2 0x00000000004226a0 in any_persistent_commands() () at
gdb/gdbserver/mem-break.c:308
#3 0x000000000042cb43 in handle_detach(char*) (own_buf=0x6f0280 "D;62ea") at
src/gdb/gdbserver/server.c:1210
#4 0x0000000000433af3 in process_serial_event() () at
src/gdb/gdbserver/server.c:4055
#5 0x0000000000434878 in handle_serial_event(int, void*) (err=0,
client_data=0x0)
The "eliminate stop_pc" commit exposes the problem because before that
commit, GDB's switch_to_thread always read the newly-selected thread's
PC, and that would end up forcing GDBserver's selected thread to
change accordingly as side effect. After that commit, GDB no longer
reads the thread's PC, and GDBserver does not switch the thread.
Fix this by removing the assumption from GDBserver.
gdb/gdbserver/ChangeLog:
2018-07-11 Pedro Alves <palves@redhat.com>
PR gdb/23377
* mem-break.c (any_persistent_commands): Add process_info
parameter and use it instead of relying on the current process.
Change return type to bool.
* mem-break.h (any_persistent_commands): Add process_info
parameter and change return type to bool.
* server.c (handle_detach): Remove require_running_or_return call.
Look up the process_info for the process we're about to detach.
If not found, return back error to GDB. Adjust
any_persistent_commands call to pass down a process pointer.
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
reinsert_breakpoint is used for software single step, so it is more
clear to rename it to single_step_breakpoint. This was pointed out in
the review https://sourceware.org/ml/gdb-patches/2016-05/msg00429.html
I don't rename "other_breakpoint" in this patch.
gdb/gdbserver:
2016-09-02 Yao Qi <yao.qi@linaro.org>
* linux-low.c: Replace "reinsert_breakpoints" with
"single_step_breakpoints". Replace "reinsert breakpoints"
with "single-step breakpoints".
* mem-break.c: Likewise.
* mem-break.h: Likewise.
This patch makes reinsert_breakpoint thread specific, which means we
insert and remove reinsert_breakpoint breakpoints for a specific
thread. This motivation of this change is that I'll use
reinsert_breakpoint for vCont;s on software single step target, so that
GDBserver may insert one reinsert_breakpoint for one thread doing
step-over, and insert one reinsert_breakpoint for another thread doing
vCont;s. After the operation of one thread is finished, GDBserver must
remove reinsert_breakpoint for that thread only.
On the other hand, reinsert_breakpoint is used for step-over nowadays.
GDBserver inserts reinsert_breakpoint, and wait only from the thread
doing step-over. After the step-over is done, GDBserver removes the
reinsert_breakpoint. If there is still any threads need step-over, do
the same again until all threads are finished step-over. In other words,
reinsert_breakpoint is globally thread specific, but in an implicit way.
It is natural to make it explicitly thread specific.
gdb/gdbserver:
2016-07-21 Yao Qi <yao.qi@linaro.org>
* mem-break.c (struct reinsert_breakpoint) <ptid>: New field.
(set_reinsert_breakpoint): New parameter ptid. Callers updated.
(clone_one_breakpoint): Likewise.
(delete_reinsert_breakpoints): Change parameter to thread.
Callers updated.
(has_reinsert_breakpoints): Likewise.
(uninsert_reinsert_breakpoints): Likewise.
(reinsert_reinsert_breakpoints): Likewise.
* mem-break.h (set_reinsert_breakpoint): Update declaration.
(delete_reinsert_breakpoints): Likewise.
(reinsert_reinsert_breakpoints): Likewise.
(uninsert_reinsert_breakpoints): Likewise.
(has_reinsert_breakpoints): Likewise.
This patch is to change the interface of clone_all_breakpoints, from
lists of breakpoints and raw_breakpoints to child thread and parent
thread. I choose child thread to pass because we need the ptid of
the child thread in the following patch.
gdb/gdbserver:
2016-07-21 Yao Qi <yao.qi@linaro.org>
* inferiors.c (get_thread_process): Make parameter const.
* inferiors.h (get_thread_process): Update declaration.
* mem-break.c (clone_all_breakpoints): Remove all parameters.
Add new parameters child_thread and parent_thread. Callers
updated.
* mem-break.h (clone_all_breakpoints): Update declaration.
Nowadays, there are three types of breakpoint in GDBserver,
- gdb breakpoints,
- reinsert breakpoints, used for software single step,
- other breakpoints, used for tracepoint,
but we only have one 'struct breakpoint' for all of them. Some fields
are only useful to one type of breakpoint. For example, cond_list
and command_list are only used by gdb breakpoints, while handler is
only used by other breakpoints.
This patch changes 'struct breakpoint' to a base class, which has fields
needed by all breakpoint types, also add three sub-classes to
'struct breakpoint' to these three types of breakpoints.
gdb/gdbserver:
2016-07-21 Yao Qi <yao.qi@linaro.org>
* mem-break.c (struct breakpoint) <cond_list>: Remove.
<command_list, handler>: Remove.
(struct gdb_breakpoint): New.
(struct other_breakpoint): New.
(struct reinsert_breakpoint): New.
(is_gdb_breakpoint): New function.
(any_persistent_commands): Update command_list if
is_gdb_breakpoint returns true.
(set_breakpoint): Create breakpoints according to their types.
(find_gdb_breakpoint): Return 'struct gdb_breakpoint *'.
(set_gdb_breakpoint_1): Likewise.
(set_gdb_breakpoint): Likewise.
(clear_breakpoint_conditions): Change parameter type to
'struct gdb_breakpoint *'.
(clear_breakpoint_commands): Likewise.
(clear_breakpoint_conditions_and_commands): Likewise.
(add_condition_to_breakpoint): Likewise.
(add_breakpoint_condition): Likewise.
(add_commands_to_breakpoint): Likewise.
(check_breakpoints): Check other_breakpoint.
(clone_one_breakpoint): Clone breakpopint according to its type.
* mem-break.h (struct gdb_breakpoint): Declare.
(set_gdb_breakpoint): Update declaration.
(clear_breakpoint_conditions_and_commands): Likewise.
(add_breakpoint_condition): Likewise.
(add_breakpoint_commands): Likewise.
* server.c (process_point_options): Change parameter type to
'struct gdb_breakpoint *'.
Nowadays, set_breakpoint_at creates breakpoint of type
other_breakpoint, but we also use set_breakpoint_at
in set_reinsert_breakpoint to create breakpoint, so that
we have to overwrite the breakpoint type like this,
bp = set_breakpoint_at (stop_at, NULL);
bp->type = reinsert_breakpoint;
which looks not very good. This patch changes set_breakpoint_at
to receive breakpoint type. Since set_breakpoint_at is
used in many places, I rename it to set_breakpoint_type_at, and wrap
it with set_breakpoint_at, and pass other_breakpoint. In this way,
we can call set_breakpoint_type_at with reinsert_breakpoint in
set_reinsert_breakpoint too, and code looks cleaner.
gdb/gdbserver:
2016-07-21 Yao Qi <yao.qi@linaro.org>
* mem-break.c (set_breakpoint_at): Rename it to ...
(set_breakpoint_type_at): ... it.
(set_breakpoint_at): Call set_breakpoint_type_at.
(set_reinsert_breakpoint): Call set_breakpoint_type_at.
* mem-break.h (set_breakpoint_at): Update comments.
When a thread is doing step-over with reinsert breakpoint, and the
instruction executed is a syscall doing vfork, both parent and child
share the memory, so the reinsert breakpoint in the space is visible
to both of them. Also, removing the reinsert breakpoints from the
child will effectively remove them from the parent. We should
carefully manipulate reinsert breakpoints for both processes.
What we are doing here is that
- uninsert reinsert breakpoints from the parent before cloning the
breakpoint list. We use "uninsert" instead of "remove", because
we need to "reinsert" them back after vfork is done. In fact,
"uninsert" removes them from both child and parent process space.
- reinsert breakpoints in parent process are still copied to child's
breakpoint list,
- remove them from child's breakpoint list as what we did for fork,
at this point, reinsert breakpoints are removed from the child and
the parent, but they are still tracked by the parent's breakpoint
list,
- once vfork is done, "reinsert" them back to the parent,
gdb/gdbserver:
2016-06-17 Yao Qi <yao.qi@linaro.org>
* linux-low.c (handle_extended_wait): Call
uninsert_reinsert_breakpoints for the parent process. Remove
reinsert breakpoints from the child process. Reinsert them to
the parent process when vfork is done.
* mem-break.c (uninsert_reinsert_breakpoints): New function.
(reinsert_reinsert_breakpoints): New function.
* mem-break.h (uninsert_reinsert_breakpoints): Declare
(reinsert_reinsert_breakpoints): Declare.
This patch adds some sanity check that reinsert breakpoints must be
there when doing step-over on software single step target. The check
triggers an assert when running forking-threads-plus-breakpoint.exp
on arm-linux target,
gdb/gdbserver/linux-low.c:4714: A problem internal to GDBserver has been detected.^M
int finish_step_over(lwp_info*): Assertion `has_reinsert_breakpoints ()' failed.
the error happens when GDBserver has already resumed a thread of
process A for step-over (and wait for it hitting reinsert breakpoint),
but receives detach request for process B from GDB, which is shown in
the backtrace below,
(gdb) bt
#2 0x000228aa in finish_step_over (lwp=0x12bbd98) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4703
#3 0x00025a50 in finish_step_over (lwp=0x12bbd98) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4749
#4 complete_ongoing_step_over () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4760
#5 linux_detach (pid=25228) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:1503
#6 0x00012bae in process_serial_event () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:3974
#7 handle_serial_event (err=<optimized out>, client_data=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:4347
#8 0x00016d68 in handle_file_event (event_file_desc=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/event-loop.c:429
#9 0x000173ea in process_event () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/event-loop.c:184
#10 start_event_loop () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/event-loop.c:547
#11 0x0000aa2c in captured_main (argv=<optimized out>, argc=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:3719
#12 main (argc=<optimized out>, argv=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:3804
the sanity check tries to find the reinsert breakpoint from process B,
but nothing is found. It is wrong, we need to search in process A,
since we started step-over of a thread of process A.
(gdb) p lwp->thread->entry.id
$3 = {pid = 25120, lwp = 25131, tid = 0}
(gdb) p current_thread->entry.id
$4 = {pid = 25228, lwp = 25228, tid = 0}
This patch switched current_thread to the thread we are doing step-over
in finish_step_over.
gdb/gdbserver:
2016-06-17 Yao Qi <yao.qi@linaro.org>
* linux-low.c (maybe_hw_step): New function.
(linux_resume_one_lwp_throw): Call maybe_hw_step.
(finish_step_over): Switch current_thread to lwp temporarily,
and assert has_reinsert_breakpoints returns true.
(proceed_one_lwp): Call maybe_hw_step.
* mem-break.c (has_reinsert_breakpoints): New function.
* mem-break.h (has_reinsert_breakpoints): Declare.
Without this patch, when doing a software single step, with for example
a conditional breakpoint, gdbserver would wrongly avance the pc of
breakpoint_len and skips an instruction.
This is due to gdbserver assuming that it's hardware single stepping.
When it resumes from the breakpoint address it expects the trap to be
caused by ptrace and if it's rather caused by a software breakpoint
it assumes this is a permanent breakpoint and that it needs to skip
over it.
However when software single stepping, this breakpoint is legitimate as
it's the reinsert breakpoint gdbserver has put in place to break at
the next instruction. Thus gdbserver wrongly advances the pc and skips
an instruction.
This patch fixes this behavior so that gdbserver checks if it is a
reinsert breakpoint from software single stepping. If it is it won't
advance the pc. And if there's no reinsert breakpoint there we assume
then that it's a permanent breakpoint and advance the pc.
Here's a commented log of what would happen before and after the fix on
gdbserver :
/* Here there is a conditional breakpoint at 0x10428 that needs to be
stepped over. */
Need step over [LWP 11204]? yes, found breakpoint at 0x10428
...
/* e7f001f0 is a breakpoint instruction on arm
Here gdbserver writes the software breakpoint we would like to hit
*/
Writing e7f001f0 to 0x0001042c in process 11204
...
Resuming lwp 11220 (continue, signal 0, stop not expected)
pending reinsert at 0x10428
stop pc is 00010428
continue from pc 0x10428
...
/* Here gdbserver hit the software breakpoint that was in place
for the step over */
stop pc is 0001042c
pc is 0x1042c
step-over for LWP 11220.11220 executed software breakpoint
Finished step over.
Could not find fast tracepoint jump at 0x10428 in list (reinserting).
/* Here gdbserver writes back the original instruction */
Writing e50b3008 to 0x0001042c in process 11220
Step-over finished.
Need step over [LWP 11220]? No
/* Here because gdbserver assumes this is a permenant breakpoint it advances
the pc of breakpoint_len, in this case 4 bytes, so we have just skipped
the instruction that was written back here :
Writing e50b3008 to 0x0001042c in process 11220
*/
stop pc is 00010430
pc is 0x10430
Need step over [LWP 11220]? No, no breakpoint found at 0x10430
Proceeding, no step-over needed
proceed_one_lwp: lwp 11220
stop pc is 00010430
This patch fixes this situation and we get the right behavior :
Writing e50b3008 to 0x0001042c in process 11245
Hit a gdbserver breakpoint.
Hit a gdbserver breakpoint.
Step-over finished.
proceeding all threads.
Need step over [LWP 11245]? No
stop pc is 0001042c
pc is 0x1042c
Need step over [LWP 11245]? No, no breakpoint found at 0x1042c
Proceeding, no step-over needed
proceed_one_lwp: lwp 11245
stop pc is 0001042c
pc is 0x1042c
Resuming lwp 11245 (continue, signal 0, stop not expected)
stop pc is 0001042c
continue from pc 0x1042c
It also works if the value at 0x0001042c is a permanent breakpoint.
If so gdbserver will finish the step over, remove the reinserted breakpoint,
resume at that location and on the next SIGTRAP gdbserver will trigger
the advance PC condition as reinsert_breakpoint_inserted_here will be false.
I also tested this against bp-permanent.exp on arm (with a work in progress
software single step patchset) without any regressions.
It's also tested against x86 bp-permanent.exp without any regression.
So both software and hardware single step are tested.
No regressions on Ubuntu 14.04 on ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_wait_1): Fix pc advance condition.
* mem-break.c (reinsert_breakpoint_inserted_here): New function.
* mem-break.h (reinsert_breakpoint_inserted_here): New declaration.
There's two ways to set breakpoints in GDBServer.
- GDBServer setting its own breakpoints, through API set_breakpoint_at.
- GDBServer setting breakpoints according to the information in Z
packets, through API set_gdb_breakpoint.
Before this patch the breakpoint kinds were a concept unique to GDB and Z
packets, as GDBServer never had to set different kinds of breakpoint on its
own.
This patch teaches GDBServer to handle breakpoint kinds for its own
breakpoints. It generalizes the breakpoint kind as per Z packets to
represent different kinds of breakpoints directly set by GDBServer also.
GDBServer now querys breakpoint_kind_from_pc to know what breakpoint kind to
set on its own.
As the kind is now a differentiating factor equivalent to size for the
breakpoint struct and that it's size can be queried using
sw_breakpoint_from_kind, the size field has been replaced with the kind field.
All references to size are now replaced by kind or a call to bp_size that wraps
sw_breakpoing_from_kind and returns the size of the breakpoint in memory.
To fetch the software breakpoint data bp_opcode is called and wraps the
sw_breakpoint_from_kind call.
No regressions on Ubuntu 14.04 on ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-low.c (initialize_low): Ajdust for breakpoint global variables
removal.
* mem-break.c : Remove breakpoint_data/breakpoint_len global variables.
(struct raw_breakpoint) <size>: Remove.
(struct raw_breakpoint) <kind>: Add.
(bp_size): New function.
(bp_opcode): Likewise.
(find_raw_breakpoint_at): Adjust for kind.
(insert_memory_breakpoint): Adjust for kind call bp_size,bp_opcode.
(remove_memory_breakpoint): Adjust for kind call bp_size.
(set_raw_breakpoint_at): Adjust for kind.
(set_breakpoint): Likewise.
(set_breakpoint_at): Call breakpoint_kind_from_pc.
(delete_raw_breakpoint): Adjust for kind.
(delete_breakpoint): Likewise.
(find_gdb_breakpoint): Likewise.
(set_gdb_breakpoint_1): Likewise.
(set_gdb_breakpoint): Likewise.
(delete_gdb_breakpoint_1): Likewise.
(delete_gdb_breakpoint): Likewise.
(uninsert_raw_breakpoint): Likewise.
(reinsert_raw_breakpoint): Likewise.
(set_breakpoint_data): Remove.
(validate_inserted_breakpoint): Adjust for kind call bp_size,bp_opcode.
(check_mem_read): Adjust for kind call bp_size.
(check_mem_write): Adjust for kind call bp_size,bp_opcode.
(clone_one_breakpoint): Adjust for kind.
* mem-break.h (set_gdb_breakpoint): Likewise.
(delete_gdb_breakpoint): Likewise.
* server.c (process_serial_event): Likewise.
This patch implements gdbserver routines to clone the breakpoint lists of a
process, duplicating them for another process. In gdbserver, each process
maintains its own independent breakpoint list. When a fork call creates a
child, all of the breakpoints currently inserted in the parent process are
also inserted in the child process, but there is nothing to describe them
in the data structures related to the child. The child must have a
breakpoint list describing them so that they can be removed (if detaching)
or recognized (if following). Implementation is a mechanical process of
just cloning the lists in several new functions in gdbserver/mem-break.c.
Tested by building, since none of the new functions are called yet. This
was tested with another patch in the series that implements follow-fork.
gdb/gdbserver/ChangeLog:
* mem-break.c (APPEND_TO_LIST): Define macro.
(clone_agent_expr): New function.
(clone_one_breakpoint): New function.
(clone_all_breakpoints): New function.
* mem-break.h: Declare new functions.
This patch applies the same starvation avoidance improvements of the
previous patch to the Linux gdbserver side.
Without this, the test added by the following commit
(gdb.threads/non-stop-fair-events.exp) always fails with time outs.
gdb/gdbserver/
2015-01-09 Pedro Alves <palves@redhat.com>
* linux-low.c (step_over_bkpt): Move higher up in the file.
(handle_extended_wait): Don't store the stop_pc here.
(get_stop_pc): Adjust comments and rename to ...
(check_stopped_by_breakpoint): ... this. Record whether the LWP
stopped for a software breakpoint or hardware breakpoint.
(thread_still_has_status_pending_p): New function.
(status_pending_p_callback): Use
thread_still_has_status_pending_p. If the event is no longer
interesting, resume the LWP.
(handle_tracepoints): Add assert.
(maybe_move_out_of_jump_pad): Remove cancel_breakpoints call.
(wstatus_maybe_breakpoint): New function.
(cancel_breakpoint): Delete function.
(check_stopped_by_watchpoint): New function, factored out from
linux_low_filter_event.
(lp_status_maybe_breakpoint): Delete function.
(linux_low_filter_event): Remove filter_ptid argument.
Leave thread group exits pending here. Store the LWP's stop PC.
Always leave events pending.
(linux_wait_for_event_filtered): Pull all events out of the
kernel, and leave them all pending.
(count_events_callback, select_event_lwp_callback): Consider all
events.
(cancel_breakpoints_callback, linux_cancel_breakpoints): Delete.
(select_event_lwp): Only give preference to the stepping LWP in
all-stop mode. Adjust comments.
(ignore_event): New function.
(linux_wait_1): Delete 'retry' label. Use ignore_event. Remove
references to cancel_breakpoints. Adjust to renames. Also give
equal priority to all LWPs that have had events in non-stop mode.
If reporting a software breakpoint event, unadjust the LWP's PC.
(linux_wait): If linux_wait_1 returned an ignored event, retry.
(stuck_in_jump_pad_callback, move_out_of_jump_pad_callback):
Adjust.
(linux_resume_one_lwp): Store the LWP's PC. Adjust.
(resume_status_pending_p): Use thread_still_has_status_pending_p.
(linux_stopped_by_watchpoint): Adjust.
(linux_target_ops): Remove reference to linux_cancel_breakpoints.
* linux-low.h (enum lwp_stop_reason): New.
(struct lwp_info) <stop_pc>: Adjust comment.
<stopped_by_watchpoint>: Delete field.
<stop_reason>: New field.
* linux-x86-low.c (x86_linux_prepare_to_resume): Adjust.
* mem-break.c (software_breakpoint_inserted_here)
(hardware_breakpoint_inserted_here): New function.
* mem-break.h (software_breakpoint_inserted_here)
(hardware_breakpoint_inserted_here): Declare.
* target.h (struct target_ops) <cancel_breakpoints>: Remove field.
(cancel_breakpoints): Delete.
* tracepoint.c (clear_installed_tracepoints, stop_tracing)
(upload_fast_traceframes): Remove references to
cancel_breakpoints.
If GDB decides to change the breakpoint's conditions or commands,
it'll reinsert the same breakpoint again, with the new options
attached, without deleting the previous breakpoint. E.g.,
(gdb) set breakpoint always-inserted on
(gdb) b main if 0
Breakpoint 1 at 0x400594: file foo.c, line 21.
Sending packet: $Z0,400594,1;X3,220027#68...Packet received: OK
(gdb) b main
Breakpoint 15 at 0x400594: file foo.c, line 21.
Sending packet: $Z0,400594,1#49...Packet received: OK
GDBserver understands this and deletes the breakpoint's previous
conditions. But, it forgets to delete the previous commands.
gdb/gdbserver/
2014-06-02 Pedro Alves <palves@redhat.com>
* ax.c (gdb_free_agent_expr): New function.
* ax.h (gdb_free_agent_expr): New declaration.
* mem-break.c (delete_gdb_breakpoint_1): Also clear the commands
list.
(clear_breakpoint_conditions, clear_breakpoint_commands): Make
static.
(clear_breakpoint_conditions_and_commands): New function.
* mem-break.h (clear_breakpoint_conditions): Delete declaration.
(clear_breakpoint_conditions_and_commands): New declaration.
This patch fixes hardware breakpoint regressions exposed by my fix for
"PR breakpoints/7143 - Watchpoint does not trigger when first set", at
https://sourceware.org/ml/gdb-patches/2014-03/msg00167.html
The testsuite caught them on Linux/x86_64, at least. gdb.sum:
gdb.sum:
FAIL: gdb.base/hbreak2.exp: next over recursive call
FAIL: gdb.base/hbreak2.exp: backtrace from factorial(5.1)
FAIL: gdb.base/hbreak2.exp: continue until exit at recursive next test
gdb.log:
(gdb) next
Program received signal SIGTRAP, Trace/breakpoint trap.
factorial (value=4) at ../../../src/gdb/testsuite/gdb.base/break.c:113
113 if (value > 1) { /* set breakpoint 7 here */
(gdb) FAIL: gdb.base/hbreak2.exp: next over recursive call
Actually, that patch just exposed a latent issue to "breakpoints
always-inserted off" mode, not really caused it. After that patch,
GDB no longer removes breakpoints at each internal event, thus making
some scenarios behave like breakpoint always-inserted on. The bug is
easy to trigger with always-inserted on.
The issue is that since the target-side breakpoint conditions support,
if the stub/server supports evaluating breakpoint conditions on the
target side, then GDB is sending duplicate Zx packets to the target
without removing them before, and GDBserver is not really expecting
that for Z packets other than Z0/z0. E.g., with "set breakpoint
always-inserted on" and "set debug remote 1":
(gdb) b main
Sending packet: $m410943,1#ff...Packet received: 48
Breakpoint 4 at 0x410943: file ../../../src/gdb/gdbserver/server.c, line 3028.
Sending packet: $Z0,410943,1#48...Packet received: OK
^^^^^^^^^^^^
(gdb) b main
Note: breakpoint 4 also set at pc 0x410943.
Sending packet: $m410943,1#ff...Packet received: 48
Breakpoint 5 at 0x410943: file ../../../src/gdb/gdbserver/server.c, line 3028.
Sending packet: $Z0,410943,1#48...Packet received: OK
^^^^^^^^^^^^
(gdb) b main
Note: breakpoints 4 and 5 also set at pc 0x410943.
Sending packet: $m410943,1#ff...Packet received: 48
Breakpoint 6 at 0x410943: file ../../../src/gdb/gdbserver/server.c, line 3028.
Sending packet: $Z0,410943,1#48...Packet received: OK
^^^^^^^^^^^^
(gdb) del
Delete all breakpoints? (y or n) y
Sending packet: $Z0,410943,1#48...Packet received: OK
Sending packet: $Z0,410943,1#48...Packet received: OK
Sending packet: $z0,410943,1#68...Packet received: OK
And for Z1, similarly:
(gdb) hbreak main
Sending packet: $m410943,1#ff...Packet received: 48
Hardware assisted breakpoint 4 at 0x410943: file ../../../src/gdb/gdbserver/server.c, line 3028.
Sending packet: $Z1,410943,1#49...Packet received: OK
^^^^^^^^^^^^
Packet Z1 (hardware-breakpoint) is supported
(gdb) hbreak main
Note: breakpoint 4 also set at pc 0x410943.
Sending packet: $m410943,1#ff...Packet received: 48
Hardware assisted breakpoint 5 at 0x410943: file ../../../src/gdb/gdbserver/server.c, line 3028.
Sending packet: $Z1,410943,1#49...Packet received: OK
^^^^^^^^^^^^
(gdb) hbreak main
Note: breakpoints 4 and 5 also set at pc 0x410943.
Sending packet: $m410943,1#ff...Packet received: 48
Hardware assisted breakpoint 6 at 0x410943: file ../../../src/gdb/gdbserver/server.c, line 3028.
Sending packet: $Z1,410943,1#49...Packet received: OK
^^^^^^^^^^^^
(gdb) del
Delete all breakpoints? (y or n) y
Sending packet: $Z1,410943,1#49...Packet received: OK
^^^^^^^^^^^^
Sending packet: $Z1,410943,1#49...Packet received: OK
^^^^^^^^^^^^
Sending packet: $z1,410943,1#69...Packet received: OK
^^^^^^^^^^^^
So GDB sent a bunch of Z1 packets, and then when finally removing the
breakpoint, only one z1 packet was sent. On the GDBserver side (with
monitor set debug-hw-points 1), in the Z1 case, we see:
$ ./gdbserver :9999 ./gdbserver
Process ./gdbserver created; pid = 8629
Listening on port 9999
Remote debugging from host 127.0.0.1
insert_watchpoint (addr=410943, len=1, type=instruction-execute):
CONTROL (DR7): 00000101 STATUS (DR6): 00000000
DR0: addr=0x410943, ref.count=1 DR1: addr=0x0, ref.count=0
DR2: addr=0x0, ref.count=0 DR3: addr=0x0, ref.count=0
insert_watchpoint (addr=410943, len=1, type=instruction-execute):
CONTROL (DR7): 00000101 STATUS (DR6): 00000000
DR0: addr=0x410943, ref.count=2 DR1: addr=0x0, ref.count=0
DR2: addr=0x0, ref.count=0 DR3: addr=0x0, ref.count=0
insert_watchpoint (addr=410943, len=1, type=instruction-execute):
CONTROL (DR7): 00000101 STATUS (DR6): 00000000
DR0: addr=0x410943, ref.count=3 DR1: addr=0x0, ref.count=0
DR2: addr=0x0, ref.count=0 DR3: addr=0x0, ref.count=0
insert_watchpoint (addr=410943, len=1, type=instruction-execute):
CONTROL (DR7): 00000101 STATUS (DR6): 00000000
DR0: addr=0x410943, ref.count=4 DR1: addr=0x0, ref.count=0
DR2: addr=0x0, ref.count=0 DR3: addr=0x0, ref.count=0
insert_watchpoint (addr=410943, len=1, type=instruction-execute):
CONTROL (DR7): 00000101 STATUS (DR6): 00000000
DR0: addr=0x410943, ref.count=5 DR1: addr=0x0, ref.count=0
DR2: addr=0x0, ref.count=0 DR3: addr=0x0, ref.count=0
remove_watchpoint (addr=410943, len=1, type=instruction-execute):
CONTROL (DR7): 00000101 STATUS (DR6): 00000000
DR0: addr=0x410943, ref.count=4 DR1: addr=0x0, ref.count=0
DR2: addr=0x0, ref.count=0 DR3: addr=0x0, ref.count=0
That's one insert_watchpoint call for each Z1 packet, and then one
remove_watchpoint call for the z1 packet. Notice how ref.count
increased for each insert_watchpoint call, and then in the end, after
GDB told GDBserver to forget about the hardware breakpoint, GDBserver
ends with the the first debug register still with ref.count=4! IOW,
the hardware breakpoint is left armed on the target, while on the GDB
end it's gone. If the program happens to execute 0x410943 afterwards,
then the CPU traps, GDBserver reports the trap to GDB, and GDB not
having a breakpoint set at that address anymore, reports to the user a
spurious SIGTRAP.
This is exactly what is happening in the hbreak2.exp test, though in
that case, it's a shared library event that triggers a
breakpoint_re_set, when breakpoints are still inserted (because
nowadays GDB doesn't remove breakpoints while handling internal
events), and that recreates breakpoint locations, which likewise
forces breakpoint reinsertion and Zx packet resends...
That is a lot of bogus Zx duplication that should possibly be
addressed on the GDB side. GDB resends Zx packets because the way to
change the target-side condition, is to resend the breakpoint to the
server with the new condition. (That's an option in the packet: e.g.,
"Z1,410943,1;X3,220027" for "hbreak main if 0". The packets in the
examples above are shorter because the breakpoints don't have
conditions attached). GDB doesn't remove the breakpoint first before
reinserting it because that'd be bad for non-stop, as it'd open a
window where the inferior could miss the breakpoint. The conditions
actually haven't changed between the resends, but GDB isn't smart
enough to realize that.
(TBC, if the target doesn't support target-side conditions, then GDB
doesn't trigger these resends (init_bp_location calls
mark_breakpoint_location_modified, and that does nothing if condition
evaluation is on the host side. The resends are caused by the
'loc->condition_changed = condition_modified.' line.)
But, even if GDB was made smarter, GDBserver should really still
handle the resends anyway. So target-side conditions also aren't
really to blame. The documentation of the Z/z packets says:
"To avoid potential problems with duplicate packets, the operations
should be implemented in an idempotent way."
As such, we may want to fix GDB, but we should definitely fix
GDBserver. The fix is a prerequisite for target-side conditions on
hardware breakpoints anyway (and while at it, on watchpoints too).
GDBserver indeed already treats duplicate Z0 packets in an idempotent
way. mem-break.c has the concept of high-level and low-level
breakpoints, somewhat similar to GDB's split of breakpoints vs
breakpoint locations, and keeps track of multiple breakpoints
referencing the same address/location, for the case of an internal
GDBserver breakpoint or a tracepoint being set at the same address as
a GDB breakpoint. But, it only allows GDB to ever contribute one
reference to a software breakpoint location. IOW, if gdbserver sees a
Z0 packet for the same address where it already had a GDB breakpoint
set, then GDBserver won't create another high-level GDB breakpoint.
However, mem-break.c only tracks GDB Z0 breakpoints. The same logic
should apply to all kinds of Zx packets. Currently, gdbserver passes
down each duplicate Zx (other than Z0) request directly to the
target->insert_point routine. The x86 watchpoint support itself
refcounts watchpoint / hw breakpoint requests, to handle overlapping
watchpoints, and save debug registers. But that code doesn't (and
really shouldn't) handle the duplicate requests, assuming that for
each insert there will be a corresponding remove.
So the fix is to generalize mem-break.c to track all kinds of Zx
breakpoints, and filter out duplicates. As mentioned, this ends up
adding support for target-side conditions on hardware breakpoints and
watchpoints too (though GDB itself doesn't support the latter yet).
Probably the least obvious change in the patch is that it kind of
turns the breakpoint insert/remove APIs inside out. Before, the
target methods were only called for GDB breakpoints. The internal
breakpoint set/delete methods inserted memory breakpoints directly
bypassing the insert/remove target methods. That's not good when the
target should use a debug API to set software breakpoints, instead of
relying on GDBserver patching memory with breakpoint instructions, as
is the case of NTO.
Now removal/insertion of all kinds of breakpoints/watchpoints, either
internal, or from GDB, always go through the target methods. The
insert_point/remove_point methods no longer get passed a Z packet
type, but an internal/raw breakpoint type. They're also passed a
pointer to the raw breakpoint itself (note that's still opaque outside
mem-break.c), so that insert_memory_breakpoint /
remove_memory_breakpoint have access to the breakpoint's shadow
buffer. I first tried passing down a new structure based on GDB's
"struct bp_target_info" (actually with that name exactly), but then
decided against it as unnecessary complication.
As software/memory breakpoints work by poking at memory, when setting
a GDB Z0 breakpoint (but not internal breakpoints, as those can assume
the conditions are already right), we need to tell the target to
prepare to access memory (which on Linux means stop threads). If that
operation fails, we need to return error to GDB. Seeing an error, if
this is the first breakpoint of that type that GDB tries to insert,
GDB would then assume the breakpoint type is supported, but it may
actually not be. So we need to check whether the type is supported at
all before preparing to access memory. And to solve that, the patch
adds a new target->supports_z_point_type method that is called before
actually trying to insert the breakpoint.
Other than that, hopefully the change is more or less obvious.
New test added that exercises the hbreak2.exp regression in a more
direct way, without relying on a breakpoint re-set happening before
main is reached.
Tested by building GDBserver for:
aarch64-linux-gnu
arm-linux-gnueabihf
i686-pc-linux-gnu
i686-w64-mingw32
m68k-linux-gnu
mips-linux-gnu
mips-uclinux
nios2-linux-gnu
powerpc-linux-gnu
sh-linux-gnu
tilegx-unknown-linux-gnu
x86_64-redhat-linux
x86_64-w64-mingw32
And also regression tested on x86_64 Fedora 20.
gdb/gdbserver/
2014-05-20 Pedro Alves <palves@redhat.com>
* linux-aarch64-low.c (aarch64_insert_point)
(aarch64_remove_point): No longer check whether the type is
supported here. Adjust to new interface.
(the_low_target): Install aarch64_supports_z_point_type as
supports_z_point_type method.
* linux-arm-low.c (raw_bkpt_type_to_arm_hwbp_type): New function.
(arm_linux_hw_point_initialize): Take an enum raw_bkpt_type
instead of a Z packet char. Adjust.
(arm_supports_z_point_type): New function.
(arm_insert_point, arm_remove_point): Adjust to new interface.
(the_low_target): Install arm_supports_z_point_type.
* linux-crisv32-low.c (cris_supports_z_point_type): New function.
(cris_insert_point, cris_remove_point): Adjust to new interface.
Don't check whether the type is supported here.
(the_low_target): Install cris_supports_z_point_type.
* linux-low.c (linux_supports_z_point_type): New function.
(linux_insert_point, linux_remove_point): Adjust to new interface.
* linux-low.h (struct linux_target_ops) <insert_point,
remove_point>: Take an enum raw_bkpt_type instead of a char. Add
raw_breakpoint pointer parameter.
<supports_z_point_type>: New method.
* linux-mips-low.c (mips_supports_z_point_type): New function.
(mips_insert_point, mips_remove_point): Adjust to new interface.
Use mips_supports_z_point_type.
(the_low_target): Install mips_supports_z_point_type.
* linux-ppc-low.c (the_low_target): Install NULL as
supports_z_point_type method.
* linux-s390-low.c (the_low_target): Install NULL as
supports_z_point_type method.
* linux-sparc-low.c (the_low_target): Install NULL as
supports_z_point_type method.
* linux-x86-low.c (x86_supports_z_point_type): New function.
(x86_insert_point): Adjust to new insert_point interface. Use
insert_memory_breakpoint. Adjust to new
i386_low_insert_watchpoint interface.
(x86_remove_point): Adjust to remove_point interface. Use
remove_memory_breakpoint. Adjust to new
i386_low_remove_watchpoint interface.
(the_low_target): Install x86_supports_z_point_type.
* lynx-low.c (lynx_target_ops): Install NULL as
supports_z_point_type callback.
* nto-low.c (nto_supports_z_point_type): New.
(nto_insert_point, nto_remove_point): Adjust to new interface.
(nto_target_ops): Install nto_supports_z_point_type.
* mem-break.c: Adjust intro comment.
(struct raw_breakpoint) <raw_type, size>: New fields.
<inserted>: Update comment.
<shlib_disabled>: Delete field.
(enum bkpt_type) <gdb_breakpoint>: Delete value.
<gdb_breakpoint_Z0, gdb_breakpoint_Z1, gdb_breakpoint_Z2,
gdb_breakpoint_Z3, gdb_breakpoint_Z4>: New values.
(raw_bkpt_type_to_target_hw_bp_type): New function.
(find_enabled_raw_code_breakpoint_at): New function.
(find_raw_breakpoint_at): New type and size parameters. Use them.
(insert_memory_breakpoint): New function, based off
set_raw_breakpoint_at.
(remove_memory_breakpoint): New function.
(set_raw_breakpoint_at): Reimplement.
(set_breakpoint): New, based on set_breakpoint_at.
(set_breakpoint_at): Reimplement.
(delete_raw_breakpoint): Go through the_target->remove_point
instead of assuming memory breakpoints.
(find_gdb_breakpoint_at): Delete.
(Z_packet_to_bkpt_type, Z_packet_to_raw_bkpt_type): New functions.
(find_gdb_breakpoint): New function.
(set_gdb_breakpoint_at): Delete.
(z_type_supported): New function.
(set_gdb_breakpoint_1): New function, loosely based off
set_gdb_breakpoint_at.
(check_gdb_bp_preconditions, set_gdb_breakpoint): New functions.
(delete_gdb_breakpoint_at): Delete.
(delete_gdb_breakpoint_1): New function, loosely based off
delete_gdb_breakpoint_at.
(delete_gdb_breakpoint): New function.
(clear_gdb_breakpoint_conditions): Rename to ...
(clear_breakpoint_conditions): ... this. Don't handle a NULL
breakpoint.
(add_condition_to_breakpoint): Make static.
(add_breakpoint_condition): Take a struct breakpoint pointer
instead of an address. Adjust.
(gdb_condition_true_at_breakpoint): Rename to ...
(gdb_condition_true_at_breakpoint_z_type): ... this, and add
z_type parameter.
(gdb_condition_true_at_breakpoint): Reimplement.
(add_breakpoint_commands): Take a struct breakpoint pointer
instead of an address. Adjust.
(gdb_no_commands_at_breakpoint): Rename to ...
(gdb_no_commands_at_breakpoint_z_type): ... this. Add z_type
parameter. Return true if no breakpoint was found. Change debug
output.
(gdb_no_commands_at_breakpoint): Reimplement.
(run_breakpoint_commands): Rename to ...
(run_breakpoint_commands_z_type): ... this. Add z_type parameter,
and change return type to boolean.
(run_breakpoint_commands): New function.
(gdb_breakpoint_here): Also check for Z1 breakpoints.
(uninsert_raw_breakpoint): Don't try to reinsert a disabled
breakpoint. Go through the_target->remove_point instead of
assuming memory breakpoint.
(uninsert_breakpoints_at, uninsert_all_breakpoints): Uninsert
software and hardware breakpoints.
(reinsert_raw_breakpoint): Go through the_target->insert_point
instead of assuming memory breakpoint.
(reinsert_breakpoints_at, reinsert_all_breakpoints): Reinsert
software and hardware breakpoints.
(check_breakpoints, breakpoint_here, breakpoint_inserted_here):
Check both software and hardware breakpoints.
(validate_inserted_breakpoint): Assert the breakpoint is a
software breakpoint. Set the inserted flag to -1 instead of
setting shlib_disabled.
(delete_disabled_breakpoints): Adjust.
(validate_breakpoints): Only validate software breakpoints.
Adjust to inserted flag change.
(check_mem_read, check_mem_write): Skip breakpoint types other
than software breakpoints. Adjust to inserted flag change.
* mem-break.h (enum raw_bkpt_type): New enum.
(raw_breakpoint, struct process_info): Forward declare.
(Z_packet_to_target_hw_bp_type): Delete declaration.
(raw_bkpt_type_to_target_hw_bp_type, Z_packet_to_raw_bkpt_type)
(set_gdb_breakpoint, delete_gdb_breakpoint)
(clear_breakpoint_conditions): New declarations.
(set_gdb_breakpoint_at, clear_gdb_breakpoint_conditions): Delete.
(breakpoint_inserted_here): Update comment.
(add_breakpoint_condition, add_breakpoint_commands): Replace
address parameter with a breakpoint pointer parameter.
(gdb_breakpoint_here): Update comment.
(delete_gdb_breakpoint_at): Delete.
(insert_memory_breakpoint, remove_memory_breakpoint): Declare.
* server.c (process_point_options): Take a struct breakpoint
pointer instead of an address. Adjust.
(process_serial_event) <Z/z packets>: Use set_gdb_breakpoint and
delete_gdb_breakpoint.
* spu-low.c (spu_target_ops): Install NULL as
supports_z_point_type method.
* target.h: Include mem-break.h.
(struct target_ops) <prepare_to_access_memory>: Update comment.
<supports_z_point_type>: New field.
<insert_point, remove_point>: Take an enum raw_bkpt_type argument
instead of a char. Also take a raw breakpoint pointer.
* win32-arm-low.c (the_low_target): Install NULL as
supports_z_point_type.
* win32-i386-low.c (i386_supports_z_point_type): New function.
(i386_insert_point, i386_remove_point): Adjust to new interface.
(the_low_target): Install i386_supports_z_point_type.
* win32-low.c (win32_supports_z_point_type): New function.
(win32_insert_point, win32_remove_point): Adjust to new interface.
(win32_target_ops): Install win32_supports_z_point_type.
* win32-low.h (struct win32_target_ops):
<supports_z_point_type>: New method.
<insert_point, remove_point>: Take an enum raw_bkpt_type argument
instead of a char. Also take a raw breakpoint pointer.
gdb/testsuite/
2014-05-20 Pedro Alves <palves@redhat.com>
* gdb.base/break-idempotent.c: New file.
* gdb.base/break-idempotent.exp: New file.
The Aarch64, MIPS and x86 Linux backends all have Z packet number
defines and corresponding protocol number to internal type convertion
routines. Factor them all out to gdbserver's core code, so we only
have one shared copy.
Tested on x86_64 Fedora 20, and also cross built for aarch64-linux-gnu
and mips-linux-gnu.
gdb/gdbserver/
2014-05-20 Pedro Alves <palves@redhat.com>
* mem-break.h: Include break-common.h.
(Z_PACKET_SW_BP, Z_PACKET_HW_BP, Z_PACKET_WRITE_WP)
(Z_PACKET_READ_WP, Z_PACKET_ACCESS_WP): New defines.
(Z_packet_to_target_hw_bp_type): New declaration.
* mem-break.c (Z_packet_to_target_hw_bp_type): New function.
* i386-low.c (Z_PACKET_HW_BP, Z_PACKET_WRITE_WP, Z_PACKET_READ_WP)
(Z_PACKET_ACCESS_WP): Delete macros.
(Z_packet_to_hw_type): Delete function.
* i386-low.h: Don't include break-common.h here.
(Z_packet_to_hw_type): Delete declaration.
* linux-x86-low.c (x86_insert_point, x86_insert_point): Call
Z_packet_to_target_hw_bp_type instead of Z_packet_to_hw_type.
* win32-i386-low.c (i386_insert_point, i386_remove_point): Call
Z_packet_to_target_hw_bp_type instead of Z_packet_to_hw_type.
* linux-aarch64-low.c: Don't include break-common.h here.
(Z_PACKET_SW_BP, Z_PACKET_HW_BP, Z_PACKET_WRITE_WP)
(Z_PACKET_READ_WP, Z_PACKET_ACCESS_WP): Delete macros.
(Z_packet_to_target_hw_bp_type): Delete function.
* linux-mips-low.c (rsp_bp_type_to_target_hw_bp_type): Delete
function.
(mips_insert_point, mips_remove_point): Use
Z_packet_to_target_hw_bp_type.
While trying to fix hbreak2.exp against GDBserver I noticed this...
(gdb) hbreak main if 1
Sending packet: $m400580,40#2e...Packet received: e8d2ffffff5dc3554889e54883ec10c745fc00000000eb0eb800000000e8c1ffffff8345fc01817dfce70300007ee9b800000000c9c3662e0f1f840000000000
Sending packet: $m40058f,1#31...Packet received: c7
Hardware assisted breakpoint 1 at 0x40058f: file ../../../src/gdb/testsuite/gdb.base/break-idempotent.c, line 46.
Sending packet: $Z1,40058f,1;X3,220127#9b...
*hangs forever*
The issue is that nothing advances the packet pointer if
add_breakpoint_condition either fails to parse the agent expression,
or fails to find the breakpoint, resulting in an infinite loop in
process_point_options. The latter case should really be fixed by
GDBserver tracking GDB Z1 breakpoints in its breakpoint structures
like Z0 breakpoints are, but the latter case still needs handling.
add_breakpoint_commands has the same issue, though at present I don't
know any way to trigger it other than sending a manually cooked
packet.
Unbelievably, it doesn't look like we have any test that tries setting
a conditional hardware breakpoint. Looking at cond-eval-mode.exp, it
looks like the file was meant to actually test something, but it's
mostly empty today. This patch adds tests that tries all sorts of
conditional breakpoints and watchpoints. The test hangs/fails without
the GDBserver fix.
Tested on x86_64 Fedora 17.
gdb/gdbserver/
2014-04-10 Pedro Alves <palves@redhat.com>
* mem-break.c (add_breakpoint_condition, add_breakpoint_commands):
Check if the condition or command is NULL before checking if the
breakpoint is known. On success, return true.
* mem-break.h (add_breakpoint_condition): Document return.
(add_breakpoint_commands): Add describing comment.
* server.c (skip_to_semicolon): New function.
(process_point_options): Use it.
gdb/testsuite/
2014-04-10 Pedro Alves <palves@redhat.com>
* gdb.base/cond-eval-mode.c: New file.
* gdb.base/cond-eval-mode.exp: Use standard_testfile. Adjust
prepare_for_testing to build the new file. Check result of
runto_main.
(test_break, test_watch): New procedures.
(top level): Use them.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
* server.c (handle_query): Advertise support for target-side
breakpoint condition evaluation.
(process_point_options): New function.
(process_serial_event): When inserting a breakpoint, check for
a target-side condition that should be evaluated.
* mem-break.c: Include regcache.h and ax.h.
(point_cond_list_t): New data structure.
(breakpoint) <cond_list>: New field.
(find_gdb_breakpoint_at): Make non-static.
(delete_gdb_breakpoint_at): Clear any target-side
conditions.
(clear_gdb_breakpoint_conditions): New function.
(add_condition_to_breakpoint): Likewise.
(add_breakpoint_condition): Likewise.
(gdb_condition_true_at_breakpoint): Likewise.
(gdb_breakpoint_here): Return result directly instead
of going through a local variable.
* mem-break.h (find_gdb_breakpoint_at): New prototype.
(clear_gdb_breakpoint_conditions): Likewise.
(add_breakpoint_condition): Likewise.
(gdb_condition_true_at_breakpoint): Likewise.
* linux-low.c (linux_wait_1): Evaluate target-side breakpoint condition.
(need_step_over_p): Take target-side breakpoint condition into
consideration.
(linux_kill): Stop all lwps here. Don't delete the main lwp here.
(linux_detach_one_lwp): Assume the lwp is stopped.
(any_thread_of): Delete.
(linux_detach): Stop all lwps here. Don't blindly delete all
breakpoints.
(delete_lwp_callback): New.
(linux_mourn): Delete all lwps of the process that is gone.
(linux_wait_1): Don't delete the last lwp of the process here.
* mem-break.h (mark_breakpoints_out): Declare.
* mem-break.c (mark_breakpoints_out): New.
(free_all_breakpoints): Use it.
* server.c (handle_target_event): If the process is gone, mark
breakpoints out.
* thread-db.c (struct thread_db) <create_bp>: New field.
(thread_db_enable_reporting): Fix prototype. Store a thread event
breakpoint reference in the thread_db struct.
(thread_db_load_search): Clear the thread_db object.
(try_thread_db_load_1): Ditto.
(switch_to_process): New.
(disable_thread_event_reporting): Use it.
(remove_thread_event_breakpoints): New.
(thread_db_detach, thread_db_mourn): Use it.
(set_gdb_breakpoint_at): If GDB is inserting a breakpoint on top
of another, then delete the previous, and validate all
breakpoints.
(validate_inserted_breakpoint): New.
(delete_disabled_breakpoints): New.
(validate_breakpoints): New.
(check_mem_read): Validate breakpoints before trusting their
shadow. Delete disabled breakpoints.
(check_mem_write): Validate breakpoints before trusting they
should be inserted. Delete disabled breakpoints.
* mem-break.h (validate_breakpoints):
* server.c (handle_query): Validate breakpoints when we see a
qSymbol query.
there's a GDB breakpoint at stop_pc. Always report a trap to GDB
if we could tell there's a GDB breakpoint at stop_pc.
(need_step_over_p): Don't do a step over if we find a GDB
breakpoint at the resume PC.
* mem-break.c (struct raw_breakpoint): New.
(enum bkpt_type): New type `gdb_breakpoint'.
(struct breakpoint): Delete the `PC', `old_data' and `inserted'
fields. New field `raw'.
(find_raw_breakpoint_at): New.
(set_raw_breakpoint_at): Handle refcounting. Create a raw
breakpoint instead.
(set_breakpoint_at): Adjust.
(delete_raw_breakpoint): New.
(release_breakpoint): New.
(delete_breakpoint): Rename to...
(delete_breakpoint_1): ... this. Add proc parameter. Use
release_breakpoint. Return ENOENT.
(delete_breakpoint): Reimplement.
(find_breakpoint_at): Delete.
(find_gdb_breakpoint_at): New.
(delete_breakpoint_at): Delete.
(set_gdb_breakpoint_at): New.
(delete_gdb_breakpoint_at): New.
(gdb_breakpoint_here): New.
(set_reinsert_breakpoint): Use release_breakpoint.
(uninsert_breakpoint): Rename to ...
(uninsert_raw_breakpoint): ... this.
(uninsert_breakpoints_at): Adjust to handle raw breakpoints.
(reinsert_raw_breakpoint): Change parameter type to
raw_breakpoint.
(reinsert_breakpoints_at): Adjust to handle raw breakpoints
instead.
(check_breakpoints): Adjust. Use release_breakpoint.
(breakpoint_here): Rewrite using find_raw_breakpoint_at.
(breakpoint_inserted_here): Ditto.
(check_mem_read): Adjust to iterate over raw breakpoints instead.
Don't trust the breakpoint's shadow if it is not inserted.
(check_mem_write): Adjust to iterate over raw breakpoints instead.
(delete_all_breakpoints): Adjust.
(free_all_breakpoints): Mark all breakpoints as uninserted, and
use delete_breakpoint_1.
* mem-break.h (breakpoints_supported): Delete declaration.
(set_gdb_breakpoint_at): Declare.
(gdb_breakpoint_here): Declare.
(delete_breakpoint_at): Delete.
(delete_gdb_breakpoint_at): Declare.
* server.h (struct raw_breakpoint): Forward declare.
(struct process_info): New field `raw_breakpoints'.
* linux-x86-low.c (x86_insert_point, x86_remote_point): Handle Z0
breakpoints.
(struct breakpoint): New field `type'.
(set_breakpoint_at): Change return type to struct breakpoint
pointer. Set type to `other_breakpoint' by default.
(delete_breakpoint): Rewrite, supporting more than one breakpoint
in the breakpoint list.
(delete_reinsert_breakpoints): Only delete reinsert breakpoints.
(reinsert_breakpoint): Rename to ...
(reinsert_raw_breakpoint): ... this.
(reinsert_breakpoints_at): Adjust.
* mem-break.h (struct breakpoint): Declare.
(set_breakpoint_at): Change return type to struct breakpoint
pointer.
Implement the multiprocess extensions, and add linux multiprocess
support.
* server.h (ULONGEST): Declare.
(struct ptid, ptid_t): New.
(minus_one_ptid, null_ptid): Declare.
(ptid_build, pid_to_ptid, ptid_get_pid, ptid_get_lwp)
(ptid_get_tid, ptid_equal, ptid_is_pid): Declare.
(struct inferior_list_entry): Change `id' type from unsigned from
to ptid_t.
(struct sym_cache, struct breakpoint, struct
process_info_private): Forward declare.
(struct process_info): Declare.
(current_process): Declare.
(all_processes): Declare.
(initialize_inferiors): Declare.
(add_thread): Adjust to use ptid_t.
(thread_id_to_gdb_id, thread_to_gdb_id, gdb_id_to_thread_id): Ditto.
(add_process, remove_process, find_thread_pid): Declare.
(find_inferior_id): Adjust to use ptid_t.
(cont_thread, general_thread, step_thread): Change type to ptid_t.
(multi_process): Declare.
(push_event): Adjust to use ptid_t.
(read_ptid, write_ptid): Declare.
(prepare_resume_reply): Adjust to use ptid_t.
(clear_symbol_cache): Declare.
* inferiors.c (all_processes): New.
(null_ptid, minus_one_ptid): New.
(ptid_build, pid_to_ptid, ptid_get_pid, ptid_get_lwp)
(ptid_get_tid, ptid_equal, ptid_is_pid): New.
(add_thread): Change unsigned long to ptid. Remove gdb_id
parameter. Adjust.
(thread_id_to_gdb_id, thread_to_gdb_id): Change unsigned long to ptid.
(gdb_id_to_thread): Rename to ...
(find_thread_pid): ... this. Change unsigned long to ptid.
(gdb_id_to_thread_id, find_inferior_id): Change unsigned long to ptid.
(loaded_dll, pull_pid_from_list): Adjust.
(add_process, remove_process, find_process_pid)
(get_thread_process, current_process, initialize_inferiors): New.
* target.h (struct thread_resume) <thread>: Change type to ptid_t.
(struct target_waitstatus) <related_pid>: Ditto.
(struct target_ops) <kill, detach>: Add `pid' argument. Change
return type to int.
(struct target_ops) <join>: Add `pid' argument.
(struct target_ops) <thread_alive>: Change pid's type to ptid_t.
(struct target_ops) <wait>: Add `ptid' field. Change return type
to ptid.
(kill_inferior, detach_inferior, join_inferior): Add `pid' argument.
(mywait): Add `ptid' argument. Change return type to ptid_t.
(target_pid_to_str): Declare.
* target.c (set_desired_inferior): Adjust to use ptids.
(mywait): Add new `ptid' argument. Adjust.
(target_pid_to_str): New.
* mem-break.h (free_all_breakpoints): Declare.
* mem-break.c (breakpoints): Delelete.
(set_breakpoint_at, delete_breakpoint, find_breakpoint_at)
(check_mem_read, check_mem_write, delete_all_breakpoints): Adjust
to use per-process breakpoint list.
(free_all_breakpoints): New.
* remote-utils.c (struct sym_cache) <name>: Drop `const'.
(symbol_cache, all_symbols_looked_up): Delete.
(hexchars): New.
(ishex, unpack_varlen_hex, write_ptid, hex_or_minus_one,
read_ptid): New.
(prepare_resume_reply): Change ptid argument's type from unsigned
long to ptid_t. Adjust. Implement W;process and X;process.
(free_sym_cache, clear_symbol_cache): New.
(look_up_one_symbol): Adjust to per-process symbol cache. *
* server.c (cont_thread, general_thread, step_thread): Change type
to ptid_t.
(attached): Delete.
(multi_process): New.
(last_ptid): Change type to ptid_t.
(struct vstop_notif) <ptid>: Change type to ptid_t.
(queue_stop_reply, push_event): Change `ptid' argument's type to
ptid_t.
(discard_queued_stop_replies): Add `pid' argument.
(start_inferior): Adjust to use ptids. Adjust to mywait interface
changes. Don't reference the `attached' global.
(attach_inferior): Adjust to mywait interface changes.
(handle_query): Adjust to use ptids. Parse GDB's qSupported
features. Handle and report "multiprocess+". Handle
"qAttached:PID".
(handle_v_cont): Adjust to use ptids. Adjust to mywait interface
changes.
(handle_v_kill): New.
(handle_v_stopped): Adjust to use target_pid_to_str.
(handle_v_requests): Allow multiple attaches and runs when
multiprocess extensions are in effect. Handle "vKill".
(myresume): Adjust to use ptids.
(queue_stop_reply_callback): Add `arg' parameter. Handle it.
(handle_status): Adjust to discard_queued_stop_replies interface
change.
(first_thread_of, kill_inferior_callback)
(detach_or_kill_inferior_callback, join_inferiors_callback): New.
(main): Call initialize_inferiors. Adjust to use ptids, killing
and detaching from all inferiors. Handle multiprocess packet
variants.
* linux-low.h: Include gdb_proc_service.h.
(struct process_info_private): New.
(struct linux_target_ops) <pid_of>: Use ptid_get_pid.
<lwpid_of>: Use ptid_get_lwp.
(get_lwp_thread): Adjust.
(struct lwp_info): Add `dead' member.
(find_lwp_pid): Declare.
* linux-low.c (thread_db_active): Delete.
(new_inferior): Adjust comment.
(inferior_pid): Delete.
(linux_add_process): New.
(handle_extended_wait): Adjust.
(add_lwp): Change unsigned long to ptid.
(linux_create_inferior): Add process to processes table. Adjust
to use ptids. Don't set new_inferior here.
(linux_attach_lwp): Rename to ...
(linux_attach_lwp_1): ... this. Add `initial' argument. Handle
it. Adjust to use ptids.
(linux_attach_lwp): New.
(linux_attach): Add process to processes table. Don't set
new_inferior here.
(struct counter): New.
(second_thread_of_pid_p, last_thread_of_process_p): New.
(linux_kill_one_lwp): Add `args' parameter. Handle it. Adjust to
multiple processes.
(linux_kill): Add `pid' argument. Handle it. Adjust to multiple
processes. Remove process from process table.
(linux_detach_one_lwp): Add `args' parameter. Handle it. Adjust
to multiple processes.
(any_thread_of): New.
(linux_detach): Add `pid' argument, and handle it. Remove process
from processes table.
(linux_join): Add `pid' argument. Handle it.
(linux_thread_alive): Change unsighed long argument to ptid_t.
Consider dead lwps as not being alive.
(status_pending_p): Rename `dummy' argument to `arg'. Filter out
threads we're not interested in.
(same_lwp, find_lwp_pid): New.
(linux_wait_for_lwp): Change `pid' argument's type from int to
ptid_t. Adjust.
(linux_wait_for_event): Rename to ...
(linux_wait_for_event_1): ... this. Change `pid' argument's type
from int to ptid_t. Adjust.
(linux_wait_for_event): New.
(linux_wait_1): Add `ptid' argument. Change return type to
ptid_t. Adjust. Use last_thread_of_process_p. Remove processes
that exit from the process table.
(linux_wait): Add `ptid' argument. Change return type to ptid_t.
Adjust.
(mark_lwp_dead): New.
(wait_for_sigstop): Adjust to use ptids. If a process exits while
stopping all threads, mark its main lwp as dead.
(linux_set_resume_request, linux_resume_one_thread): Adjust to use
ptids.
(fetch_register, usr_store_inferior_registers)
(regsets_fetch_inferior_registers)
(regsets_store_inferior_registers, linux_read_memory)
(linux_write_memory): Inline `inferior_pid'.
(linux_look_up_symbols): Adjust to use per-process
`thread_db_active'.
(linux_request_interrupt): Adjust to use ptids.
(linux_read_auxv): Inline `inferior_pid'.
(initialize_low): Don't reference thread_db_active.
* gdb_proc_service.h (struct ps_prochandle) <pid>: Remove.
* proc-service.c (ps_lgetregs): Use find_lwp_pid.
(ps_getpid): Return the pid of the current inferior.
* thread-db.c (proc_handle, thread_agent): Delete.
(thread_db_create_event, thread_db_enable_reporting): Adjust to
per-process data.
(find_one_thread): Change argument type to ptid_t. Adjust to
per-process data.
(maybe_attach_thread): Adjust to per-process data and ptids.
(thread_db_find_new_threads): Ditto.
(thread_db_init): Ditto.
* spu-low.c (spu_create_inferior, spu_attach): Add process to
processes table. Adjust to use ptids.
(spu_kill, spu_detach): Adjust interface. Remove process from
processes table.
(spu_join, spu_thread_alive): Adjust interface.
(spu_wait): Adjust interface. Remove process from processes
table. Adjust to use ptids.
* win32-low.c (current_inferior_tid): Delete.
(current_inferior_ptid): New.
(debug_event_ptid): New.
(thread_rec): Take a ptid. Adjust.
(child_add_thread): Add `pid' argument. Adjust to use ptids.
(child_delete_thread): Ditto.
(do_initial_child_stuff): Add `attached' argument. Add process to
processes table.
(child_fetch_inferior_registers, child_store_inferior_registers):
Adjust.
(win32_create_inferior): Pass 0 to do_initial_child_stuff.
(win32_attach): Pass 1 to do_initial_child_stuff.
(win32_kill): Adjust interface. Remove process from processes
table.
(win32_detach): Ditto.
(win32_join): Adjust interface.
(win32_thread_alive): Take a ptid.
(win32_resume): Adjust to use ptids.
(get_child_debug_event): Ditto.
(win32_wait): Adjust interface. Remove exiting process from
processes table.
reinsert auto-delete breakpoints.
* mem-break.c (struct breakpoint): Change return type of handler to
int.
(set_breakpoint_at): Update handler type.
(reinsert_breakpoint_handler): Return 1 instead of calling
delete_breakpoint.
(reinsert_breakpoint_by_bp): Check for the original breakpoint before
setting a new one.
(check_breakpoints): Delete auto-delete breakpoints and return 2.
* mem-break.h (set_breakpoint_at): Update handler type.
* thread-db.c (thread_db_create_event, thread_db_create_event): Update.
* win32-low.c (auto_delete_breakpoint): New.
(get_child_debug_event): Use it.
Pedro Alves
Joel Brobecker
Yao Qi
Antoine Tremblay
Don Breazeal
Joel Brobecker
Stan Shebs
Luis Machado
Yao Qi
Daniel Jacobowitz
Eli Zaretskii