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Use keep_going in proceed and start_step_over too

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The main motivation of this patch is sharing more code between the
proceed (starting the inferior for the first time) and keep_going
(restarting the inferior after handling an event) paths and using the
step_over_chain queue now embedded in the thread_info object for
pending in-line step-overs too (instead of just for displaced
stepping).

So this commit:

 - splits out a new keep_going_pass_signal function out of keep_going
   that is just like keep_going except for the bits that clear the
   signal to pass if the signal is set to "handle nopass".

 - makes proceed use keep_going too.

 - Makes start_step_over use keep_going_pass_signal instead of lower
   level displaced stepping things.

One user visible change: if inserting breakpoints while trying to
proceed fails, we now get:

  (gdb) si
  Warning:
  Could not insert hardware watchpoint 7.
  Could not insert hardware breakpoints:
  You may have requested too many hardware breakpoints/watchpoints.

  Command aborted.
  (gdb)

while before we only saw warnings with no indication that the command
was cancelled:

  (gdb) si
  Warning:
  Could not insert hardware watchpoint 7.
  Could not insert hardware breakpoints:
  You may have requested too many hardware breakpoints/watchpoints.

  (gdb)

Tested on x86_64-linux-gnu, ppc64-linux-gnu and s390-linux-gnu.

gdb/ChangeLog:
2015-08-07  Pedro Alves  <palves@redhat.com>

	* gdbthread.h (struct thread_info) <prev_pc>: Extend comment.
	* infrun.c (struct execution_control_state): Move higher up in the
	file.
	(reset_ecs): New function.
	(start_step_over): Now returns int.  Rewrite to use
	keep_going_pass_signal instead of manually starting a displaced step.
	(resume): Don't call set_running here.  If displaced stepping
	can't start now, clear trap_expected.
	(find_thread_needs_step_over): Delete function.
	(proceed): Set up finish_thread_state_cleanup.  Call set_running.
	If the current thread needs a step over, push it in the step-over
	chain.  Don't set insert breakpoints nor call resume directly
	here.  Instead rewrite to use start_step_over and
	keep_going_pass_signal.
	(finish_step_over): New function.
	(handle_signal_stop): Call finish_step_over instead of
	start_step_over.
	(switch_back_to_stepped_thread): If the event thread needs another
	step-over do that first.  Use start_step_over.
	(keep_going_pass_signal): New function, factored out from ...
	(keep_going): ... here.
	(_initialize_infrun): Comment moved here.
	* thread.c (set_running_thread): New function.
	(set_running, finish_thread_state): Use set_running_thread.
This commit is contained in:
Pedro Alves
2015-08-07 17:23:58 +01:00
parent c2829269f5
commit 4d9d9d0423
4 changed files with 364 additions and 321 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
gdb/ChangeLog
View File

@ -1,3 +1,30 @@
2015-08-07 Pedro Alves <palves@redhat.com>
* gdbthread.h (struct thread_info) <prev_pc>: Extend comment.
* infrun.c (struct execution_control_state): Move higher up in the
file.
(reset_ecs): New function.
(start_step_over): Now returns int. Rewrite to use
keep_going_pass_signal instead of manually starting a displaced step.
(resume): Don't call set_running here. If displaced stepping
can't start now, clear trap_expected.
(find_thread_needs_step_over): Delete function.
(proceed): Set up finish_thread_state_cleanup. Call set_running.
If the current thread needs a step over, push it in the step-over
chain. Don't set insert breakpoints nor call resume directly
here. Instead rewrite to use start_step_over and
keep_going_pass_signal.
(finish_step_over): New function.
(handle_signal_stop): Call finish_step_over instead of
start_step_over.
(switch_back_to_stepped_thread): If the event thread needs another
step-over do that first. Use start_step_over.
(keep_going_pass_signal): New function, factored out from ...
(keep_going): ... here.
(_initialize_infrun): Comment moved here.
* thread.c (set_running_thread): New function.
(set_running, finish_thread_state): Use set_running_thread.
2015-08-07 Pedro Alves <palves@redhat.com> 2015-08-07 Pedro Alves <palves@redhat.com>
* gdbthread.h (struct thread_info) <step_over_prev, * gdbthread.h (struct thread_info) <step_over_prev,

6
gdb/gdbthread.h
View File

@ -206,8 +206,10 @@ struct thread_info
/* Internal stepping state. */ /* Internal stepping state. */
/* Record the pc of the thread the last time it stopped. This is /* Record the pc of the thread the last time it was resumed. (It
maintained by proceed and keep_going, and used in can't be done on stop as the PC may change since the last stop,
e.g., "return" command, or "p $pc = 0xf000"). This is maintained
by proceed and keep_going, and among other things, it's used in
adjust_pc_after_break to distinguish a hardware single-step adjust_pc_after_break to distinguish a hardware single-step
SIGTRAP from a breakpoint SIGTRAP. */ SIGTRAP from a breakpoint SIGTRAP. */
CORE_ADDR prev_pc; CORE_ADDR prev_pc;

588
gdb/infrun.c
View File

@ -1842,31 +1842,61 @@ displaced_step_fixup (ptid_t event_ptid, enum gdb_signal signal)
displaced->step_ptid = null_ptid; displaced->step_ptid = null_ptid;
} }
/* Are there any pending step-over requests? If so, run all we can /* Data to be passed around while handling an event. This data is
now. */ discarded between events. */
struct execution_control_state
{
ptid_t ptid;
/* The thread that got the event, if this was a thread event; NULL
otherwise. */
struct thread_info *event_thread;
struct target_waitstatus ws;
int stop_func_filled_in;
CORE_ADDR stop_func_start;
CORE_ADDR stop_func_end;
const char *stop_func_name;
int wait_some_more;
/* True if the event thread hit the single-step breakpoint of
another thread. Thus the event doesn't cause a stop, the thread
needs to be single-stepped past the single-step breakpoint before
we can switch back to the original stepping thread. */
int hit_singlestep_breakpoint;
};
/* Clear ECS and set it to point at TP. */
static void static void
reset_ecs (struct execution_control_state *ecs, struct thread_info *tp)
{
memset (ecs, 0, sizeof (*ecs));
ecs->event_thread = tp;
ecs->ptid = tp->ptid;
}
static void keep_going_pass_signal (struct execution_control_state *ecs);
static void prepare_to_wait (struct execution_control_state *ecs);
static int thread_still_needs_step_over (struct thread_info *tp);
/* Are there any pending step-over requests? If so, run all we can
now and return true. Otherwise, return false. */
static int
start_step_over (void) start_step_over (void)
{ {
struct thread_info *tp, *next; struct thread_info *tp, *next;
for (tp = step_over_queue_head; tp != NULL; tp = next) for (tp = step_over_queue_head; tp != NULL; tp = next)
{ {
ptid_t ptid; struct execution_control_state ecss;
struct displaced_step_inferior_state *displaced; struct execution_control_state *ecs = &ecss;
struct regcache *regcache;
struct gdbarch *gdbarch;
CORE_ADDR actual_pc;
struct address_space *aspace;
struct inferior *inf = find_inferior_ptid (tp->ptid);
next = thread_step_over_chain_next (tp); next = thread_step_over_chain_next (tp);
displaced = get_displaced_stepping_state (inf->pid);
/* If this inferior already has a displaced step in process, /* If this inferior already has a displaced step in process,
don't start a new one. */ don't start a new one. */
if (!ptid_equal (displaced->step_ptid, null_ptid)) if (displaced_step_in_progress (ptid_get_pid (tp->ptid)))
continue; continue;
thread_step_over_chain_remove (tp); thread_step_over_chain_remove (tp);
@ -1878,73 +1908,57 @@ start_step_over (void)
"infrun: step-over queue now empty\n"); "infrun: step-over queue now empty\n");
} }
ptid = tp->ptid; if (tp->control.trap_expected || tp->executing)
context_switch (ptid);
regcache = get_thread_regcache (ptid);
actual_pc = regcache_read_pc (regcache);
aspace = get_regcache_aspace (regcache);
gdbarch = get_regcache_arch (regcache);
if (breakpoint_here_p (aspace, actual_pc))
{ {
if (debug_displaced) internal_error (__FILE__, __LINE__,
"[%s] has inconsistent state: "
"trap_expected=%d, executing=%d\n",
target_pid_to_str (tp->ptid),
tp->control.trap_expected,
tp->executing);
}
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog, fprintf_unfiltered (gdb_stdlog,
"displaced: stepping queued %s now\n", "infrun: resuming [%s] for step-over\n",
target_pid_to_str (ptid)); target_pid_to_str (tp->ptid));
displaced_step_prepare (ptid); /* keep_going_pass_signal skips the step-over if the breakpoint
is no longer inserted. In all-stop, we want to keep looking
for a thread that needs a step-over instead of resuming TP,
because we wouldn't be able to resume anything else until the
target stops again. In non-stop, the resume always resumes
only TP, so it's OK to let the thread resume freely. */
if (!non_stop && !thread_still_needs_step_over (tp))
continue;
if (debug_displaced) switch_to_thread (tp->ptid);
reset_ecs (ecs, tp);
keep_going_pass_signal (ecs);
if (!ecs->wait_some_more)
error (_("Command aborted."));
if (!non_stop)
{ {
CORE_ADDR actual_pc = regcache_read_pc (regcache); /* On all-stop, shouldn't have resumed unless we needed a
gdb_byte buf[4]; step over. */
gdb_assert (tp->control.trap_expected
|| tp->step_after_step_resume_breakpoint);
fprintf_unfiltered (gdb_stdlog, "displaced: run %s: ", /* With remote targets (at least), in all-stop, we can't
paddress (gdbarch, actual_pc)); issue any further remote commands until the program stops
read_memory (actual_pc, buf, sizeof (buf)); again. */
displaced_step_dump_bytes (gdb_stdlog, buf, sizeof (buf)); return 1;
} }
if (gdbarch_displaced_step_hw_singlestep (gdbarch, /* Either the thread no longer needed a step-over, or a new
displaced->step_closure)) displaced stepping sequence started. Even in the latter
target_resume (ptid, 1, GDB_SIGNAL_0); case, continue looking. Maybe we can also start another
else displaced step on a thread of other process. */
target_resume (ptid, 0, GDB_SIGNAL_0);
/* Done, we're stepping a thread. */
}
else
{
int step;
struct thread_info *tp = inferior_thread ();
/* The breakpoint we were sitting under has since been
removed. */
tp->control.trap_expected = 0;
/* Go back to what we were trying to do. */
step = currently_stepping (tp);
if (step)
step = maybe_software_singlestep (gdbarch, actual_pc);
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog,
"displaced: breakpoint is gone: %s, step(%d)\n",
target_pid_to_str (tp->ptid), step);
target_resume (ptid, step, GDB_SIGNAL_0);
tp->suspend.stop_signal = GDB_SIGNAL_0;
/* This request was discarded. See if there's any other
thread waiting for its turn. */
} }
/* A new displaced stepping sequence started. Maybe we can return 0;
start a displaced step on a thread of other process.
Continue looking. */
}
} }
/* Update global variables holding ptids to hold NEW_PTID if they were /* Update global variables holding ptids to hold NEW_PTID if they were
@ -2281,13 +2295,11 @@ resume (enum gdb_signal sig)
if (!displaced_step_prepare (inferior_ptid)) if (!displaced_step_prepare (inferior_ptid))
{ {
/* Got placed in displaced stepping queue. Will be resumed if (debug_infrun)
later when all the currently queued displaced stepping fprintf_unfiltered (gdb_stdlog,
requests finish. The thread is not executing at this "Got placed in step-over queue\n");
point, and the call to set_executing will be made later.
But we need to call set_running here, since from the tp->control.trap_expected = 0;
user/frontend's point of view, threads were set running. */
set_running (user_visible_resume_ptid (user_step), 1);
discard_cleanups (old_cleanups); discard_cleanups (old_cleanups);
return; return;
} }
@ -2362,12 +2374,6 @@ resume (enum gdb_signal sig)
by applying increasingly restricting conditions. */ by applying increasingly restricting conditions. */
resume_ptid = user_visible_resume_ptid (user_step); resume_ptid = user_visible_resume_ptid (user_step);
/* Even if RESUME_PTID is a wildcard, and we end up resuming less
(e.g., we might need to step over a breakpoint), from the
user/frontend's point of view, all threads in RESUME_PTID are now
running. */
set_running (resume_ptid, 1);
/* Maybe resume a single thread after all. */ /* Maybe resume a single thread after all. */
if ((step || thread_has_single_step_breakpoints_set (tp)) if ((step || thread_has_single_step_breakpoints_set (tp))
&& tp->control.trap_expected) && tp->control.trap_expected)
@ -2576,48 +2582,6 @@ schedlock_applies (struct thread_info *tp)
&& tp->control.stepping_command)); && tp->control.stepping_command));
} }
/* Look a thread other than EXCEPT that has previously reported a
breakpoint event, and thus needs a step-over in order to make
progress. Returns NULL is none is found. */
static struct thread_info *
find_thread_needs_step_over (struct thread_info *except)
{
struct thread_info *tp, *current;
/* With non-stop mode on, threads are always handled individually. */
gdb_assert (! non_stop);
current = inferior_thread ();
/* If scheduler locking applies, we can avoid iterating over all
threads. */
if (schedlock_applies (except))
{
if (except != current
&& thread_still_needs_step_over (current))
return current;
return NULL;
}
ALL_NON_EXITED_THREADS (tp)
{
/* Ignore the EXCEPT thread. */
if (tp == except)
continue;
/* Ignore threads of processes we're not resuming. */
if (!sched_multi
&& ptid_get_pid (tp->ptid) != ptid_get_pid (inferior_ptid))
continue;
if (thread_still_needs_step_over (tp))
return tp;
}
return NULL;
}
/* Basic routine for continuing the program in various fashions. /* Basic routine for continuing the program in various fashions.
ADDR is the address to resume at, or -1 for resume where stopped. ADDR is the address to resume at, or -1 for resume where stopped.
@ -2638,6 +2602,11 @@ proceed (CORE_ADDR addr, enum gdb_signal siggnal)
struct thread_info *tp; struct thread_info *tp;
CORE_ADDR pc; CORE_ADDR pc;
struct address_space *aspace; struct address_space *aspace;
ptid_t resume_ptid;
struct execution_control_state ecss;
struct execution_control_state *ecs = &ecss;
struct cleanup *old_chain;
int started;
/* If we're stopped at a fork/vfork, follow the branch set by the /* If we're stopped at a fork/vfork, follow the branch set by the
"set follow-fork-mode" command; otherwise, we'll just proceed "set follow-fork-mode" command; otherwise, we'll just proceed
@ -2700,7 +2669,23 @@ proceed (CORE_ADDR addr, enum gdb_signal siggnal)
(next/step/etc.), we'll want to print stop event output to the MI (next/step/etc.), we'll want to print stop event output to the MI
console channel (the stepped-to line, etc.), as if the user console channel (the stepped-to line, etc.), as if the user
entered the execution command on a real GDB console. */ entered the execution command on a real GDB console. */
inferior_thread ()->control.command_interp = command_interp (); tp->control.command_interp = command_interp ();
resume_ptid = user_visible_resume_ptid (tp->control.stepping_command);
/* If an exception is thrown from this point on, make sure to
propagate GDB's knowledge of the executing state to the
frontend/user running state. */
old_chain = make_cleanup (finish_thread_state_cleanup, &resume_ptid);
/* Even if RESUME_PTID is a wildcard, and we end up resuming fewer
threads (e.g., we might need to set threads stepping over
breakpoints first), from the user/frontend's point of view, all
threads in RESUME_PTID are now running. Unless we're calling an
inferior function, as in that case we pretend the inferior
doesn't run at all. */
if (!tp->control.in_infcall)
set_running (resume_ptid, 1);
if (debug_infrun) if (debug_infrun)
fprintf_unfiltered (gdb_stdlog, fprintf_unfiltered (gdb_stdlog,
@ -2708,91 +2693,92 @@ proceed (CORE_ADDR addr, enum gdb_signal siggnal)
paddress (gdbarch, addr), paddress (gdbarch, addr),
gdb_signal_to_symbol_string (siggnal)); gdb_signal_to_symbol_string (siggnal));
if (non_stop)
/* In non-stop, each thread is handled individually. The context
must already be set to the right thread here. */
;
else
{
struct thread_info *step_over;
/* In a multi-threaded task we may select another thread and
then continue or step.
But if the old thread was stopped at a breakpoint, it will
immediately cause another breakpoint stop without any
execution (i.e. it will report a breakpoint hit incorrectly).
So we must step over it first.
Look for a thread other than the current (TP) that reported a
breakpoint hit and hasn't been resumed yet since. */
step_over = find_thread_needs_step_over (tp);
if (step_over != NULL)
{
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog,
"infrun: need to step-over [%s] first\n",
target_pid_to_str (step_over->ptid));
/* Store the prev_pc for the stepping thread too, needed by
switch_back_to_stepped_thread. */
tp->prev_pc = regcache_read_pc (get_current_regcache ());
switch_to_thread (step_over->ptid);
tp = step_over;
}
}
/* If we need to step over a breakpoint, and we're not using
displaced stepping to do so, insert all breakpoints (watchpoints,
etc.) but the one we're stepping over, step one instruction, and
then re-insert the breakpoint when that step is finished. */
if (tp->stepping_over_breakpoint && !use_displaced_stepping (gdbarch))
{
struct regcache *regcache = get_current_regcache ();
set_step_over_info (get_regcache_aspace (regcache),
regcache_read_pc (regcache), 0);
}
else
clear_step_over_info ();
insert_breakpoints ();
tp->control.trap_expected = tp->stepping_over_breakpoint;
annotate_starting (); annotate_starting ();
/* Make sure that output from GDB appears before output from the /* Make sure that output from GDB appears before output from the
inferior. */ inferior. */
gdb_flush (gdb_stdout); gdb_flush (gdb_stdout);
/* Refresh prev_pc value just prior to resuming. This used to be /* In a multi-threaded task we may select another thread and
done in stop_waiting, however, setting prev_pc there did not handle then continue or step.
scenarios such as inferior function calls or returning from
a function via the return command. In those cases, the prev_pc
value was not set properly for subsequent commands. The prev_pc value
is used to initialize the starting line number in the ecs. With an
invalid value, the gdb next command ends up stopping at the position
represented by the next line table entry past our start position.
On platforms that generate one line table entry per line, this
is not a problem. However, on the ia64, the compiler generates
extraneous line table entries that do not increase the line number.
When we issue the gdb next command on the ia64 after an inferior call
or a return command, we often end up a few instructions forward, still
within the original line we started.
An attempt was made to refresh the prev_pc at the same time the But if a thread that we're resuming had stopped at a breakpoint,
execution_control_state is initialized (for instance, just before it will immediately cause another breakpoint stop without any
waiting for an inferior event). But this approach did not work execution (i.e. it will report a breakpoint hit incorrectly). So
because of platforms that use ptrace, where the pc register cannot we must step over it first.
be read unless the inferior is stopped. At that point, we are not
guaranteed the inferior is stopped and so the regcache_read_pc() call
can fail. Setting the prev_pc value here ensures the value is updated
correctly when the inferior is stopped. */
tp->prev_pc = regcache_read_pc (get_current_regcache ());
/* Resume inferior. */ Look for threads other than the current (TP) that reported a
resume (tp->suspend.stop_signal); breakpoint hit and haven't been resumed yet since. */
/* If scheduler locking applies, we can avoid iterating over all
threads. */
if (!non_stop && !schedlock_applies (tp))
{
struct thread_info *current = tp;
ALL_NON_EXITED_THREADS (tp)
{
/* Ignore the current thread here. It's handled
afterwards. */
if (tp == current)
continue;
/* Ignore threads of processes we're not resuming. */
if (!ptid_match (tp->ptid, resume_ptid))
continue;
if (!thread_still_needs_step_over (tp))
continue;
gdb_assert (!thread_is_in_step_over_chain (tp));
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog,
"infrun: need to step-over [%s] first\n",
target_pid_to_str (tp->ptid));
thread_step_over_chain_enqueue (tp);
}
tp = current;
}
/* Enqueue the current thread last, so that we move all other
threads over their breakpoints first. */
if (tp->stepping_over_breakpoint)
thread_step_over_chain_enqueue (tp);
/* If the thread isn't started, we'll still need to set its prev_pc,
so that switch_back_to_stepped_thread knows the thread hasn't
advanced. Must do this before resuming any thread, as in
all-stop/remote, once we resume we can't send any other packet
until the target stops again. */
tp->prev_pc = regcache_read_pc (regcache);
started = start_step_over ();
if (step_over_info_valid_p ())
{
/* Either this thread started a new in-line step over, or some
other thread was already doing one. In either case, don't
resume anything else until the step-over is finished. */
}
else if (started && !non_stop)
{
/* A new displaced stepping sequence was started. In all-stop,
we can't talk to the target anymore until it next stops. */
}
else if (!tp->executing && !thread_is_in_step_over_chain (tp))
{
/* The thread wasn't started, and isn't queued, run it now. */
reset_ecs (ecs, tp);
switch_to_thread (tp->ptid);
keep_going_pass_signal (ecs);
if (!ecs->wait_some_more)
error ("Command aborted.");
}
discard_cleanups (old_chain);
/* Wait for it to stop (if not standalone) /* Wait for it to stop (if not standalone)
and in any case decode why it stopped, and act accordingly. */ and in any case decode why it stopped, and act accordingly. */
@ -2860,28 +2846,6 @@ init_wait_for_inferior (void)
} }
/* Data to be passed around while handling an event. This data is
discarded between events. */
struct execution_control_state
{
ptid_t ptid;
/* The thread that got the event, if this was a thread event; NULL
otherwise. */
struct thread_info *event_thread;
struct target_waitstatus ws;
int stop_func_filled_in;
CORE_ADDR stop_func_start;
CORE_ADDR stop_func_end;
const char *stop_func_name;
int wait_some_more;
/* True if the event thread hit the single-step breakpoint of
another thread. Thus the event doesn't cause a stop, the thread
needs to be single-stepped past the single-step breakpoint before
we can switch back to the original stepping thread. */
int hit_singlestep_breakpoint;
};
static void handle_inferior_event (struct execution_control_state *ecs); static void handle_inferior_event (struct execution_control_state *ecs);
@ -2895,7 +2859,6 @@ static void check_exception_resume (struct execution_control_state *,
static void end_stepping_range (struct execution_control_state *ecs); static void end_stepping_range (struct execution_control_state *ecs);
static void stop_waiting (struct execution_control_state *ecs); static void stop_waiting (struct execution_control_state *ecs);
static void prepare_to_wait (struct execution_control_state *ecs);
static void keep_going (struct execution_control_state *ecs); static void keep_going (struct execution_control_state *ecs);
static void process_event_stop_test (struct execution_control_state *ecs); static void process_event_stop_test (struct execution_control_state *ecs);
static int switch_back_to_stepped_thread (struct execution_control_state *ecs); static int switch_back_to_stepped_thread (struct execution_control_state *ecs);
@ -4271,6 +4234,34 @@ handle_inferior_event (struct execution_control_state *ecs)
value_free_to_mark (mark); value_free_to_mark (mark);
} }
/* Called when we get an event that may finish an in-line or
out-of-line (displaced stepping) step-over started previously. */
static void
finish_step_over (struct execution_control_state *ecs)
{
displaced_step_fixup (ecs->ptid,
ecs->event_thread->suspend.stop_signal);
if (step_over_info_valid_p ())
{
/* If we're stepping over a breakpoint with all threads locked,
then only the thread that was stepped should be reporting
back an event. */
gdb_assert (ecs->event_thread->control.trap_expected);
if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP)
clear_step_over_info ();
}
if (!non_stop)
return;
/* Start a new step-over in another thread if there's one that
needs it. */
start_step_over ();
}
/* Come here when the program has stopped with a signal. */ /* Come here when the program has stopped with a signal. */
static void static void
@ -4287,9 +4278,7 @@ handle_signal_stop (struct execution_control_state *ecs)
/* Do we need to clean up the state of a thread that has /* Do we need to clean up the state of a thread that has
completed a displaced single-step? (Doing so usually affects completed a displaced single-step? (Doing so usually affects
the PC, so do it here, before we set stop_pc.) */ the PC, so do it here, before we set stop_pc.) */
displaced_step_fixup (ecs->ptid, finish_step_over (ecs);
ecs->event_thread->suspend.stop_signal);
start_step_over ();
/* If we either finished a single-step or hit a breakpoint, but /* If we either finished a single-step or hit a breakpoint, but
the user wanted this thread to be stopped, pretend we got a the user wanted this thread to be stopped, pretend we got a
@ -5639,7 +5628,6 @@ switch_back_to_stepped_thread (struct execution_control_state *ecs)
{ {
struct thread_info *tp; struct thread_info *tp;
struct thread_info *stepping_thread; struct thread_info *stepping_thread;
struct thread_info *step_over;
/* If any thread is blocked on some internal breakpoint, and we /* If any thread is blocked on some internal breakpoint, and we
simply need to step over that breakpoint to get it going simply need to step over that breakpoint to get it going
@ -5682,14 +5670,20 @@ switch_back_to_stepped_thread (struct execution_control_state *ecs)
return 1; return 1;
} }
/* Otherwise, we no longer expect a trap in the current thread. /* If this thread needs yet another step-over (e.g., stepping
Clear the trap_expected flag before switching back -- this is through a delay slot), do it first before moving on to
what keep_going does as well, if we call it. */ another thread. */
ecs->event_thread->control.trap_expected = 0; if (thread_still_needs_step_over (ecs->event_thread))
{
/* Likewise, clear the signal if it should not be passed. */ if (debug_infrun)
if (!signal_program[ecs->event_thread->suspend.stop_signal]) {
ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0; fprintf_unfiltered (gdb_stdlog,
"infrun: thread [%s] still needs step-over\n",
target_pid_to_str (ecs->event_thread->ptid));
}
keep_going (ecs);
return 1;
}
/* If scheduler locking applies even if not stepping, there's no /* If scheduler locking applies even if not stepping, there's no
need to walk over threads. Above we've checked whether the need to walk over threads. Above we've checked whether the
@ -5699,12 +5693,26 @@ switch_back_to_stepped_thread (struct execution_control_state *ecs)
if (schedlock_applies (ecs->event_thread)) if (schedlock_applies (ecs->event_thread))
return 0; return 0;
/* Look for the stepping/nexting thread, and check if any other /* Otherwise, we no longer expect a trap in the current thread.
thread other than the stepping thread needs to start a Clear the trap_expected flag before switching back -- this is
step-over. Do all step-overs before actually proceeding with what keep_going does as well, if we call it. */
ecs->event_thread->control.trap_expected = 0;
/* Likewise, clear the signal if it should not be passed. */
if (!signal_program[ecs->event_thread->suspend.stop_signal])
ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
/* Do all pending step-overs before actually proceeding with
step/next/etc. */ step/next/etc. */
if (start_step_over ())
{
prepare_to_wait (ecs);
return 1;
}
/* Look for the stepping/nexting thread. */
stepping_thread = NULL; stepping_thread = NULL;
step_over = NULL;
ALL_NON_EXITED_THREADS (tp) ALL_NON_EXITED_THREADS (tp)
{ {
/* Ignore threads of processes we're not resuming. */ /* Ignore threads of processes we're not resuming. */
@ -5736,37 +5744,6 @@ switch_back_to_stepped_thread (struct execution_control_state *ecs)
stepping_thread = tp; stepping_thread = tp;
} }
else if (thread_still_needs_step_over (tp))
{
step_over = tp;
/* At the top we've returned early if the event thread
is stepping. If some other thread not the event
thread is stepping, then scheduler locking can't be
in effect, and we can resume this thread. No need to
keep looking for the stepping thread then. */
break;
}
}
if (step_over != NULL)
{
tp = step_over;
if (debug_infrun)
{
fprintf_unfiltered (gdb_stdlog,
"infrun: need to step-over [%s]\n",
target_pid_to_str (tp->ptid));
}
/* Only the stepping thread should have this set. */
gdb_assert (tp->control.step_range_end == 0);
ecs->ptid = tp->ptid;
ecs->event_thread = tp;
switch_to_thread (ecs->ptid);
keep_going (ecs);
return 1;
} }
if (stepping_thread != NULL) if (stepping_thread != NULL)
@ -5865,7 +5842,7 @@ switch_back_to_stepped_thread (struct execution_control_state *ecs)
fprintf_unfiltered (gdb_stdlog, fprintf_unfiltered (gdb_stdlog,
"infrun: expected thread still " "infrun: expected thread still "
"hasn't advanced\n"); "hasn't advanced\n");
keep_going (ecs); keep_going_pass_signal (ecs);
} }
return 1; return 1;
@ -6281,24 +6258,32 @@ stop_waiting (struct execution_control_state *ecs)
ecs->wait_some_more = 0; ecs->wait_some_more = 0;
} }
/* Called when we should continue running the inferior, because the /* Like keep_going, but passes the signal to the inferior, even if the
current event doesn't cause a user visible stop. This does the signal is set to nopass. */
resuming part; waiting for the next event is done elsewhere. */
static void static void
keep_going (struct execution_control_state *ecs) keep_going_pass_signal (struct execution_control_state *ecs)
{ {
/* Make sure normal_stop is called if we get a QUIT handled before /* Make sure normal_stop is called if we get a QUIT handled before
reaching resume. */ reaching resume. */
struct cleanup *old_cleanups = make_cleanup (resume_cleanups, 0); struct cleanup *old_cleanups = make_cleanup (resume_cleanups, 0);
gdb_assert (ptid_equal (ecs->event_thread->ptid, inferior_ptid));
/* Save the pc before execution, to compare with pc after stop. */ /* Save the pc before execution, to compare with pc after stop. */
ecs->event_thread->prev_pc ecs->event_thread->prev_pc
= regcache_read_pc (get_thread_regcache (ecs->ptid)); = regcache_read_pc (get_thread_regcache (ecs->ptid));
if (ecs->event_thread->control.trap_expected if (ecs->event_thread->control.trap_expected)
&& ecs->event_thread->suspend.stop_signal != GDB_SIGNAL_TRAP)
{ {
struct thread_info *tp = ecs->event_thread;
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog,
"infrun: %s has trap_expected set, "
"resuming to collect trap\n",
target_pid_to_str (tp->ptid));
/* We haven't yet gotten our trap, and either: intercepted a /* We haven't yet gotten our trap, and either: intercepted a
non-signal event (e.g., a fork); or took a signal which we non-signal event (e.g., a fork); or took a signal which we
are supposed to pass through to the inferior. Simply are supposed to pass through to the inferior. Simply
@ -6369,20 +6354,6 @@ keep_going (struct execution_control_state *ecs)
ecs->event_thread->control.trap_expected = (remove_bp || remove_wps); ecs->event_thread->control.trap_expected = (remove_bp || remove_wps);
/* Do not deliver GDB_SIGNAL_TRAP (except when the user
explicitly specifies that such a signal should be delivered
to the target program). Typically, that would occur when a
user is debugging a target monitor on a simulator: the target
monitor sets a breakpoint; the simulator encounters this
breakpoint and halts the simulation handing control to GDB;
GDB, noting that the stop address doesn't map to any known
breakpoint, returns control back to the simulator; the
simulator then delivers the hardware equivalent of a
GDB_SIGNAL_TRAP to the program being debugged. */
if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
&& !signal_program[ecs->event_thread->suspend.stop_signal])
ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
discard_cleanups (old_cleanups); discard_cleanups (old_cleanups);
resume (ecs->event_thread->suspend.stop_signal); resume (ecs->event_thread->suspend.stop_signal);
} }
@ -6390,6 +6361,22 @@ keep_going (struct execution_control_state *ecs)
prepare_to_wait (ecs); prepare_to_wait (ecs);
} }
/* Called when we should continue running the inferior, because the
current event doesn't cause a user visible stop. This does the
resuming part; waiting for the next event is done elsewhere. */
static void
keep_going (struct execution_control_state *ecs)
{
if (ecs->event_thread->control.trap_expected
&& ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP)
ecs->event_thread->control.trap_expected = 0;
if (!signal_program[ecs->event_thread->suspend.stop_signal])
ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
keep_going_pass_signal (ecs);
}
/* This function normally comes after a resume, before /* This function normally comes after a resume, before
handle_inferior_event exits. It takes care of any last bits of handle_inferior_event exits. It takes care of any last bits of
housekeeping, and sets the all-important wait_some_more flag. */ housekeeping, and sets the all-important wait_some_more flag. */
@ -7790,8 +7777,19 @@ leave it stopped or free to run as needed."),
signal_catch[i] = 0; signal_catch[i] = 0;
} }
/* Signals caused by debugger's own actions /* Signals caused by debugger's own actions should not be given to
should not be given to the program afterwards. */ the program afterwards.
Do not deliver GDB_SIGNAL_TRAP by default, except when the user
explicitly specifies that it should be delivered to the target
program. Typically, that would occur when a user is debugging a
target monitor on a simulator: the target monitor sets a
breakpoint; the simulator encounters this breakpoint and halts
the simulation handing control to GDB; GDB, noting that the stop
address doesn't map to any known breakpoint, returns control back
to the simulator; the simulator then delivers the hardware
equivalent of a GDB_SIGNAL_TRAP to the program being
debugged. */
signal_program[GDB_SIGNAL_TRAP] = 0; signal_program[GDB_SIGNAL_TRAP] = 0;
signal_program[GDB_SIGNAL_INT] = 0; signal_program[GDB_SIGNAL_INT] = 0;

52
gdb/thread.c
View File

@ -852,44 +852,62 @@ thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid)
observer_notify_thread_ptid_changed (old_ptid, new_ptid); observer_notify_thread_ptid_changed (old_ptid, new_ptid);
} }
/* Helper for set_running, that marks one thread either running or
stopped. */
static int
set_running_thread (struct thread_info *tp, int running)
{
int started = 0;
if (running && tp->state == THREAD_STOPPED)
started = 1;
tp->state = running ? THREAD_RUNNING : THREAD_STOPPED;
if (!running)
{
/* If the thread is now marked stopped, remove it from
the step-over queue, so that we don't try to resume
it until the user wants it to. */
if (tp->step_over_next != NULL)
thread_step_over_chain_remove (tp);
}
return started;
}
void void
set_running (ptid_t ptid, int running) set_running (ptid_t ptid, int running)
{ {
struct thread_info *tp; struct thread_info *tp;
int all = ptid_equal (ptid, minus_one_ptid); int all = ptid_equal (ptid, minus_one_ptid);
int any_started = 0;
/* We try not to notify the observer if no thread has actually changed /* We try not to notify the observer if no thread has actually changed
the running state -- merely to reduce the number of messages to the running state -- merely to reduce the number of messages to
frontend. Frontend is supposed to handle multiple *running just fine. */ frontend. Frontend is supposed to handle multiple *running just fine. */
if (all || ptid_is_pid (ptid)) if (all || ptid_is_pid (ptid))
{ {
int any_started = 0;
for (tp = thread_list; tp; tp = tp->next) for (tp = thread_list; tp; tp = tp->next)
if (all || ptid_get_pid (tp->ptid) == ptid_get_pid (ptid)) if (all || ptid_get_pid (tp->ptid) == ptid_get_pid (ptid))
{ {
if (tp->state == THREAD_EXITED) if (tp->state == THREAD_EXITED)
continue; continue;
if (running && tp->state == THREAD_STOPPED)
if (set_running_thread (tp, running))
any_started = 1; any_started = 1;
tp->state = running ? THREAD_RUNNING : THREAD_STOPPED;
} }
if (any_started)
observer_notify_target_resumed (ptid);
} }
else else
{ {
int started = 0;
tp = find_thread_ptid (ptid); tp = find_thread_ptid (ptid);
gdb_assert (tp); gdb_assert (tp != NULL);
gdb_assert (tp->state != THREAD_EXITED); gdb_assert (tp->state != THREAD_EXITED);
if (running && tp->state == THREAD_STOPPED) if (set_running_thread (tp, running))
started = 1; any_started = 1;
tp->state = running ? THREAD_RUNNING : THREAD_STOPPED;
if (started)
observer_notify_target_resumed (ptid);
} }
if (any_started)
observer_notify_target_resumed (ptid);
} }
static int static int
@ -1008,9 +1026,8 @@ finish_thread_state (ptid_t ptid)
continue; continue;
if (all || ptid_get_pid (ptid) == ptid_get_pid (tp->ptid)) if (all || ptid_get_pid (ptid) == ptid_get_pid (tp->ptid))
{ {
if (tp->executing && tp->state == THREAD_STOPPED) if (set_running_thread (tp, tp->executing))
any_started = 1; any_started = 1;
tp->state = tp->executing ? THREAD_RUNNING : THREAD_STOPPED;
} }
} }
} }
@ -1020,9 +1037,8 @@ finish_thread_state (ptid_t ptid)
gdb_assert (tp); gdb_assert (tp);
if (tp->state != THREAD_EXITED) if (tp->state != THREAD_EXITED)
{ {
if (tp->executing && tp->state == THREAD_STOPPED) if (set_running_thread (tp, tp->executing))
any_started = 1; any_started = 1;
tp->state = tp->executing ? THREAD_RUNNING : THREAD_STOPPED;
} }
} }