static void linux_resume (struct thread_resume *resume_info, size_t n);
static void stop_all_lwps (void);
static int linux_wait_for_event (ptid_t ptid, int *wstat, int options);
-static int check_removed_breakpoint (struct lwp_info *event_child);
static void *add_lwp (ptid_t ptid);
static int linux_stopped_by_watchpoint (void);
static void mark_lwp_dead (struct lwp_info *lwp, int wstat);
static int linux_core_of_thread (ptid_t ptid);
+static void proceed_all_lwps (void);
+static void unstop_all_lwps (struct lwp_info *except);
+static void cancel_finished_single_steps (struct lwp_info *except);
+static int finish_step_over (struct lwp_info *lwp);
+static CORE_ADDR get_stop_pc (struct lwp_info *lwp);
+static int kill_lwp (unsigned long lwpid, int signo);
+
+/* True if the low target can hardware single-step. Such targets
+ don't need a BREAKPOINT_REINSERT_ADDR callback. */
+
+static int
+can_hardware_single_step (void)
+{
+ return (the_low_target.breakpoint_reinsert_addr == NULL);
+}
+
+/* True if the low target supports memory breakpoints. If so, we'll
+ have a GET_PC implementation. */
+
+static int
+supports_breakpoints (void)
+{
+ return (the_low_target.get_pc != NULL);
+}
struct pending_signals
{
If we do get another signal, be sure not to lose it. */
if (WSTOPSIG (status) == SIGSTOP)
{
- if (! stopping_threads)
+ if (stopping_threads)
+ new_lwp->stop_pc = get_stop_pc (new_lwp);
+ else
linux_resume_one_lwp (new_lwp, 0, 0, NULL);
}
else
{
new_lwp->stop_expected = 1;
+
if (stopping_threads)
{
+ new_lwp->stop_pc = get_stop_pc (new_lwp);
new_lwp->status_pending_p = 1;
new_lwp->status_pending = status;
}
}
}
-/* This function should only be called if the process got a SIGTRAP.
+/* Return the PC as read from the regcache of LWP, without any
+ adjustment. */
+
+static CORE_ADDR
+get_pc (struct lwp_info *lwp)
+{
+ struct thread_info *saved_inferior;
+ struct regcache *regcache;
+ CORE_ADDR pc;
+
+ if (the_low_target.get_pc == NULL)
+ return 0;
+
+ saved_inferior = current_inferior;
+ current_inferior = get_lwp_thread (lwp);
+
+ regcache = get_thread_regcache (current_inferior, 1);
+ pc = (*the_low_target.get_pc) (regcache);
+
+ if (debug_threads)
+ fprintf (stderr, "pc is 0x%lx\n", (long) pc);
+
+ current_inferior = saved_inferior;
+ return pc;
+}
+
+/* This function should only be called if LWP got a SIGTRAP.
The SIGTRAP could mean several things.
On i386, where decr_pc_after_break is non-zero:
instruction. */
static CORE_ADDR
-get_stop_pc (void)
+get_stop_pc (struct lwp_info *lwp)
{
- struct regcache *regcache = get_thread_regcache (current_inferior, 1);
- CORE_ADDR stop_pc = (*the_low_target.get_pc) (regcache);
+ CORE_ADDR stop_pc;
+
+ if (the_low_target.get_pc == NULL)
+ return 0;
+
+ stop_pc = get_pc (lwp);
- if (! get_thread_lwp (current_inferior)->stepping
- && WSTOPSIG (get_thread_lwp (current_inferior)->last_status) == SIGTRAP)
+ if (WSTOPSIG (lwp->last_status) == SIGTRAP && !lwp->stepping)
stop_pc -= the_low_target.decr_pc_after_break;
if (debug_threads)
lwp->head.id = ptid;
+ lwp->last_resume_kind = resume_continue;
+
if (the_low_target.new_thread != NULL)
lwp->arch_private = the_low_target.new_thread ();
1) gdbserver has already attached to the process and is being notified
of a new thread that is being created.
- In this case we should ignore that SIGSTOP and resume the process.
- This is handled below by setting stop_expected = 1.
+ In this case we should ignore that SIGSTOP and resume the
+ process. This is handled below by setting stop_expected = 1,
+ and the fact that add_lwp sets last_resume_kind ==
+ resume_continue.
2) This is the first thread (the process thread), and we're attaching
to it via attach_inferior.
In this case we want the process thread to stop.
- This is handled by having linux_attach clear stop_expected after
- we return.
+ This is handled by having linux_attach set last_resume_kind ==
+ resume_stop after we return.
??? If the process already has several threads we leave the other
threads running.
because we are guaranteed that the add_lwp call above added us to the
end of the list, and so the new thread has not yet reached
wait_for_sigstop (but will). */
- if (! stopping_threads)
- new_lwp->stop_expected = 1;
+ new_lwp->stop_expected = 1;
}
void
process. It will be collected by wait shortly. */
lwp = (struct lwp_info *) find_inferior_id (&all_lwps,
ptid_build (pid, pid, 0));
- lwp->stop_expected = 0;
+ lwp->last_resume_kind = resume_stop;
}
return 0;
return 0;
}
- /* Make sure the process isn't stopped at a breakpoint that's
- no longer there. */
- check_removed_breakpoint (lwp);
-
/* If this process is stopped but is expecting a SIGSTOP, then make
sure we take care of that now. This isn't absolutely guaranteed
to collect the SIGSTOP, but is fairly likely to. */
return 0;
}
-/* Return nonzero if this process stopped at a breakpoint which
- no longer appears to be inserted. Also adjust the PC
- appropriately to resume where the breakpoint used to be. */
-static int
-check_removed_breakpoint (struct lwp_info *event_child)
-{
- CORE_ADDR stop_pc;
- struct thread_info *saved_inferior;
- struct regcache *regcache;
-
- if (event_child->pending_is_breakpoint == 0)
- return 0;
-
- if (debug_threads)
- fprintf (stderr, "Checking for breakpoint in lwp %ld.\n",
- lwpid_of (event_child));
-
- saved_inferior = current_inferior;
- current_inferior = get_lwp_thread (event_child);
- regcache = get_thread_regcache (current_inferior, 1);
- stop_pc = get_stop_pc ();
-
- /* If the PC has changed since we stopped, then we shouldn't do
- anything. This happens if, for instance, GDB handled the
- decr_pc_after_break subtraction itself. */
- if (stop_pc != event_child->pending_stop_pc)
- {
- if (debug_threads)
- fprintf (stderr, "Ignoring, PC was changed. Old PC was 0x%08llx\n",
- event_child->pending_stop_pc);
-
- event_child->pending_is_breakpoint = 0;
- current_inferior = saved_inferior;
- return 0;
- }
-
- /* If the breakpoint is still there, we will report hitting it. */
- if ((*the_low_target.breakpoint_at) (stop_pc))
- {
- if (debug_threads)
- fprintf (stderr, "Ignoring, breakpoint is still present.\n");
- current_inferior = saved_inferior;
- return 0;
- }
-
- if (debug_threads)
- fprintf (stderr, "Removed breakpoint.\n");
-
- /* For decr_pc_after_break targets, here is where we perform the
- decrement. We go immediately from this function to resuming,
- and can not safely call get_stop_pc () again. */
- if (the_low_target.set_pc != NULL)
- {
- if (debug_threads)
- fprintf (stderr, "Set pc to 0x%lx\n", (long) stop_pc);
- (*the_low_target.set_pc) (regcache, stop_pc);
- }
-
- /* We consumed the pending SIGTRAP. */
- event_child->pending_is_breakpoint = 0;
- event_child->status_pending_p = 0;
- event_child->status_pending = 0;
-
- current_inferior = saved_inferior;
- return 1;
-}
-
/* Return 1 if this lwp has an interesting status pending. This
function may silently resume an inferior lwp. */
static int
-status_pending_p (struct inferior_list_entry *entry, void *arg)
+status_pending_p_callback (struct inferior_list_entry *entry, void *arg)
{
struct lwp_info *lwp = (struct lwp_info *) entry;
ptid_t ptid = * (ptid_t *) arg;
+ struct thread_info *thread = get_lwp_thread (lwp);
/* Check if we're only interested in events from a specific process
or its lwps. */
&& ptid_get_pid (ptid) != ptid_get_pid (lwp->head.id))
return 0;
- if (lwp->status_pending_p && !lwp->suspended)
- if (check_removed_breakpoint (lwp))
- {
- /* This thread was stopped at a breakpoint, and the breakpoint
- is now gone. We were told to continue (or step...) all threads,
- so GDB isn't trying to single-step past this breakpoint.
- So instead of reporting the old SIGTRAP, pretend we got to
- the breakpoint just after it was removed instead of just
- before; resume the process. */
- linux_resume_one_lwp (lwp, 0, 0, NULL);
- return 0;
- }
+ thread = get_lwp_thread (lwp);
+
+ /* If we got a `vCont;t', but we haven't reported a stop yet, do
+ report any status pending the LWP may have. */
+ if (lwp->last_resume_kind == resume_stop
+ && thread->last_status.kind == TARGET_WAITKIND_STOPPED)
+ return 0;
- return (lwp->status_pending_p && !lwp->suspended);
+ return lwp->status_pending_p;
}
static int
goto retry;
child->stopped = 1;
- child->pending_is_breakpoint = 0;
child->last_status = *wstatp;
}
}
+ /* Store the STOP_PC, with adjustment applied. This depends on the
+ architecture being defined already (so that CHILD has a valid
+ regcache), and on LAST_STATUS being set (to check for SIGTRAP or
+ not). */
+ if (WIFSTOPPED (*wstatp))
+ child->stop_pc = get_stop_pc (child);
+
if (debug_threads
&& WIFSTOPPED (*wstatp)
&& the_low_target.get_pc != NULL)
struct regcache *regcache;
CORE_ADDR pc;
- current_inferior = (struct thread_info *)
- find_inferior_id (&all_threads, child->head.id);
+ current_inferior = get_lwp_thread (child);
regcache = get_thread_regcache (current_inferior, 1);
pc = (*the_low_target.get_pc) (regcache);
fprintf (stderr, "linux_wait_for_lwp: pc is 0x%lx\n", (long) pc);
return child;
}
+/* Arrange for a breakpoint to be hit again later. We don't keep the
+ SIGTRAP status and don't forward the SIGTRAP signal to the LWP. We
+ will handle the current event, eventually we will resume this LWP,
+ and this breakpoint will trap again. */
+
+static int
+cancel_breakpoint (struct lwp_info *lwp)
+{
+ struct thread_info *saved_inferior;
+ struct regcache *regcache;
+
+ /* There's nothing to do if we don't support breakpoints. */
+ if (!supports_breakpoints ())
+ return 0;
+
+ if (lwp->stepping)
+ {
+ if (debug_threads)
+ fprintf (stderr,
+ "CB: [%s] is stepping\n",
+ target_pid_to_str (lwp->head.id));
+ return 0;
+ }
+
+ regcache = get_thread_regcache (get_lwp_thread (lwp), 1);
+
+ /* breakpoint_at reads from current inferior. */
+ saved_inferior = current_inferior;
+ current_inferior = get_lwp_thread (lwp);
+
+ if ((*the_low_target.breakpoint_at) (lwp->stop_pc))
+ {
+ if (debug_threads)
+ fprintf (stderr,
+ "CB: Push back breakpoint for %s\n",
+ target_pid_to_str (lwp->head.id));
+
+ /* Back up the PC if necessary. */
+ if (the_low_target.decr_pc_after_break)
+ {
+ struct regcache *regcache
+ = get_thread_regcache (get_lwp_thread (lwp), 1);
+ (*the_low_target.set_pc) (regcache, lwp->stop_pc);
+ }
+
+ current_inferior = saved_inferior;
+ return 1;
+ }
+ else
+ {
+ if (debug_threads)
+ fprintf (stderr,
+ "CB: No breakpoint found at %s for [%s]\n",
+ paddress (lwp->stop_pc),
+ target_pid_to_str (lwp->head.id));
+ }
+
+ current_inferior = saved_inferior;
+ return 0;
+}
+
+/* When the event-loop is doing a step-over, this points at the thread
+ being stepped. */
+ptid_t step_over_bkpt;
+
/* Wait for an event from child PID. If PID is -1, wait for any
child. Store the stop status through the status pointer WSTAT.
OPTIONS is passed to the waitpid call. Return 0 if no child stop
linux_wait_for_event_1 (ptid_t ptid, int *wstat, int options)
{
CORE_ADDR stop_pc;
- struct lwp_info *event_child = NULL;
- int bp_status;
- struct lwp_info *requested_child = NULL;
+ struct lwp_info *event_child, *requested_child;
+
+ again:
+ event_child = NULL;
+ requested_child = NULL;
/* Check for a lwp with a pending status. */
- /* It is possible that the user changed the pending task's registers since
- it stopped. We correctly handle the change of PC if we hit a breakpoint
- (in check_removed_breakpoint); signals should be reported anyway. */
if (ptid_equal (ptid, minus_one_ptid)
|| ptid_equal (pid_to_ptid (ptid_get_pid (ptid)), ptid))
{
event_child = (struct lwp_info *)
- find_inferior (&all_lwps, status_pending_p, &ptid);
+ find_inferior (&all_lwps, status_pending_p_callback, &ptid);
if (debug_threads && event_child)
fprintf (stderr, "Got a pending child %ld\n", lwpid_of (event_child));
}
else
{
requested_child = find_lwp_pid (ptid);
- if (requested_child->status_pending_p
- && !check_removed_breakpoint (requested_child))
+
+ if (requested_child->status_pending_p)
event_child = requested_child;
}
events. */
while (1)
{
- event_child = linux_wait_for_lwp (ptid, wstat, options);
+ int step_over_finished = 0;
+ int bp_explains_trap = 0;
+ int cancel_sigtrap;
+
+ if (ptid_equal (step_over_bkpt, null_ptid))
+ event_child = linux_wait_for_lwp (ptid, wstat, options);
+ else
+ {
+ if (debug_threads)
+ fprintf (stderr, "step_over_bkpt set [%s], doing a blocking wait\n",
+ target_pid_to_str (step_over_bkpt));
+ event_child = linux_wait_for_lwp (step_over_bkpt,
+ wstat, options & ~WNOHANG);
+ }
if ((options & WNOHANG) && event_child == NULL)
- return 0;
+ {
+ if (debug_threads)
+ fprintf (stderr, "WNOHANG set, no event found\n");
+ return 0;
+ }
if (event_child == NULL)
error ("event from unknown child");
return lwpid_of (event_child);
}
- delete_lwp (event_child);
-
if (!non_stop)
{
current_inferior = (struct thread_info *) all_threads.head;
/* If we were waiting for this particular child to do something...
well, it did something. */
if (requested_child != NULL)
- return lwpid_of (event_child);
+ {
+ int lwpid = lwpid_of (event_child);
+
+ /* Cancel the step-over operation --- the thread that
+ started it is gone. */
+ if (finish_step_over (event_child))
+ unstop_all_lwps (event_child);
+ delete_lwp (event_child);
+ return lwpid;
+ }
+
+ delete_lwp (event_child);
/* Wait for a more interesting event. */
continue;
event_child->must_set_ptrace_flags = 0;
}
- if (WIFSTOPPED (*wstat)
- && WSTOPSIG (*wstat) == SIGSTOP
- && event_child->stop_expected)
- {
- if (debug_threads)
- fprintf (stderr, "Expected stop.\n");
- event_child->stop_expected = 0;
- linux_resume_one_lwp (event_child, event_child->stepping, 0, NULL);
- continue;
- }
-
if (WIFSTOPPED (*wstat) && WSTOPSIG (*wstat) == SIGTRAP
&& *wstat >> 16 != 0)
{
||
#endif
(pass_signals[target_signal_from_host (WSTOPSIG (*wstat))]
- && (WSTOPSIG (*wstat) != SIGSTOP || !stopping_threads))))
+ && !(WSTOPSIG (*wstat) == SIGSTOP
+ && event_child->stop_expected))))
{
siginfo_t info, *info_p;
info_p = &info;
else
info_p = NULL;
- linux_resume_one_lwp (event_child,
- event_child->stepping,
+ linux_resume_one_lwp (event_child, event_child->stepping,
WSTOPSIG (*wstat), info_p);
continue;
}
- /* If this event was not handled above, and is not a SIGTRAP,
- report it. SIGILL and SIGSEGV are also treated as traps in case
- a breakpoint is inserted at the current PC. */
+ if (WIFSTOPPED (*wstat)
+ && WSTOPSIG (*wstat) == SIGSTOP
+ && event_child->stop_expected)
+ {
+ int should_stop;
+
+ if (debug_threads)
+ fprintf (stderr, "Expected stop.\n");
+ event_child->stop_expected = 0;
+
+ should_stop = (event_child->last_resume_kind == resume_stop
+ || stopping_threads);
+
+ if (!should_stop)
+ {
+ linux_resume_one_lwp (event_child,
+ event_child->stepping, 0, NULL);
+ continue;
+ }
+ }
+
+ cancel_sigtrap = (stopping_threads
+ || event_child->last_resume_kind == resume_stop);
+
+ /* Do not allow nested internal breakpoint handling, or leave
+ the unadjusted PCs visible to GDB. Simply cancel the
+ breakpoint now, and eventually when the thread is resumed, it
+ will trap again, if the breakpoint is still there by
+ then. */
+ if (WIFSTOPPED (*wstat)
+ && WSTOPSIG (*wstat) == SIGTRAP
+ && cancel_sigtrap)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Got a nested SIGTRAP while stopping threads\n");
+
+ if (cancel_breakpoint (event_child))
+ {
+ if (debug_threads)
+ fprintf (stderr, " bkpt canceled\n");
+
+ /* We don't resume immediately to collect the SIGSTOP,
+ due to other reasons we may care for this SIGTRAP
+ below. Care must be taken to not process anything
+ breakpoint related though from this point on. */
+ }
+ }
+
+ /* If this event was not handled above, and is not a SIGTRAP, we
+ report it. SIGILL and SIGSEGV are also treated as traps in
+ case a breakpoint is inserted at the current PC. If this
+ target does not support breakpoints, we also report the
+ SIGTRAP without further processing; it's of no concern to
+ us. */
if (!WIFSTOPPED (*wstat)
- || (WSTOPSIG (*wstat) != SIGTRAP && WSTOPSIG (*wstat) != SIGILL
- && WSTOPSIG (*wstat) != SIGSEGV))
- return lwpid_of (event_child);
+ || !supports_breakpoints ()
+ || (WSTOPSIG (*wstat) != SIGTRAP
+ && WSTOPSIG (*wstat) != SIGILL
+ && WSTOPSIG (*wstat) != SIGSEGV)
+ /* Only handle SIGILL or SIGSEGV if we've hit a recognized
+ breakpoint. */
+ || (WSTOPSIG (*wstat) != SIGTRAP
+ && !(*the_low_target.breakpoint_at) (event_child->stop_pc)))
+ {
+ if (debug_threads && WIFSTOPPED (*wstat))
+ fprintf (stderr, "Reporting signal %d for LWP %ld.\n",
+ WSTOPSIG (*wstat), lwpid_of (event_child));
- /* If this target does not support breakpoints, we simply report the
- signal; it's of no concern to us. */
- if (the_low_target.get_pc == NULL)
- return lwpid_of (event_child);
+ /* If we were stepping over a breakpoint, this signal
+ arriving means we didn't manage to move past the
+ breakpoint location. Cancel the operation for now --- it
+ will be handled again on the next resume, if required
+ (the breakpoint may be removed meanwhile, for
+ example). */
+ if (finish_step_over (event_child))
+ {
+ event_child->need_step_over = 1;
+ unstop_all_lwps (event_child);
+ }
+ return lwpid_of (event_child);
+ }
+
+ stop_pc = event_child->stop_pc;
- stop_pc = get_stop_pc ();
+ /* Handle anything that requires bookkeeping before deciding to
+ report the event or continue waiting. */
- /* Only handle SIGILL or SIGSEGV if we've hit a recognized
+ /* First check if we can explain the SIGTRAP with an internal
+ breakpoint, or if we should possibly report the event to GDB.
+ Do this before anything that may remove or insert a
breakpoint. */
- if (WSTOPSIG (*wstat) != SIGTRAP
- && (event_child->stepping
- || ! (*the_low_target.breakpoint_at) (stop_pc)))
- return lwpid_of (event_child);
-
- /* bp_reinsert will only be set if we were single-stepping.
- Notice that we will resume the process after hitting
- a gdbserver breakpoint; single-stepping to/over one
- is not supported (yet). */
- if (event_child->bp_reinsert != 0)
+ bp_explains_trap = breakpoint_inserted_here (stop_pc);
+
+ /* We have a SIGTRAP, possibly a step-over dance has just
+ finished. If so, tweak the state machine accordingly,
+ reinsert breakpoints and delete any reinsert (software
+ single-step) breakpoints. */
+ step_over_finished = finish_step_over (event_child);
+
+ /* Now invoke the callbacks of any breakpoints there. */
+ if (!cancel_sigtrap)
+ check_breakpoints (stop_pc);
+
+ /* If we're stopping threads, resume once more to collect the
+ SIGSTOP, and do nothing else. Note that we don't set
+ need_step_over. If this predicate matches, then we've
+ cancelled the SIGTRAP before reaching here, and we do want
+ any breakpoint at STOP_PC to be re-hit on resume. */
+ if (stopping_threads
+ || event_child->last_resume_kind == resume_stop)
{
+ gdb_assert (cancel_sigtrap);
+
+ if (step_over_finished)
+ unstop_all_lwps (event_child);
+
if (debug_threads)
- fprintf (stderr, "Reinserted breakpoint.\n");
- reinsert_breakpoint (event_child->bp_reinsert);
- event_child->bp_reinsert = 0;
+ {
+ if (event_child->last_resume_kind == resume_stop)
+ fprintf (stderr, "Bailing out; GDB wanted the LWP to stop.\n");
+ else if (stopping_threads)
+ fprintf (stderr, "Bailing out; stopping threads.\n");
+
+ if (bp_explains_trap)
+ fprintf (stderr, " Hit a breakpoint.\n");
+ if (step_over_finished)
+ fprintf (stderr, " Step-over finished.\n");
+ if (event_child->stopped_by_watchpoint)
+ fprintf (stderr, " Stopped by watchpoint.\n");
+ }
+
+ /* Leave these pending. */
+ if (event_child->stopped_by_watchpoint)
+ return lwpid_of (event_child);
+
+ /* Otherwise, there may or not be a pending SIGSTOP. If
+ there isn't one, queue one up. In any case, go back to
+ the event loop to collect it. Don't return yet, as we
+ don't want this SIGTRAP to be left pending. Note that
+ since we cancelled the breakpoint above, the PC is
+ already adjusted, and hence get_stop_pc returns the
+ correct PC when we collect the SIGSTOP. */
+
+ if (!event_child->stop_expected)
+ {
+ event_child->stop_expected = 1;
+ kill_lwp (lwpid_of (event_child), SIGSTOP);
+ }
/* Clear the single-stepping flag and SIGTRAP as we resume. */
linux_resume_one_lwp (event_child, 0, 0, NULL);
continue;
}
- bp_status = check_breakpoints (stop_pc);
+ /* We have all the data we need. Either report the event to
+ GDB, or resume threads and keep waiting for more. */
- if (bp_status != 0)
+ /* Check If GDB would be interested in this event. If GDB
+ wanted this thread to single step, we always want to report
+ the SIGTRAP, and let GDB handle it. */
+ if ((event_child->last_resume_kind == resume_step)
+ || event_child->stopped_by_watchpoint)
{
- if (debug_threads)
- fprintf (stderr, "Hit a gdbserver breakpoint.\n");
-
- /* We hit one of our own breakpoints. We mark it as a pending
- breakpoint, so that check_removed_breakpoint () will do the PC
- adjustment for us at the appropriate time. */
- event_child->pending_is_breakpoint = 1;
- event_child->pending_stop_pc = stop_pc;
-
- /* We may need to put the breakpoint back. We continue in the event
- loop instead of simply replacing the breakpoint right away,
- in order to not lose signals sent to the thread that hit the
- breakpoint. Unfortunately this increases the window where another
- thread could sneak past the removed breakpoint. For the current
- use of server-side breakpoints (thread creation) this is
- acceptable; but it needs to be considered before this breakpoint
- mechanism can be used in more general ways. For some breakpoints
- it may be necessary to stop all other threads, but that should
- be avoided where possible.
-
- If breakpoint_reinsert_addr is NULL, that means that we can
- use PTRACE_SINGLESTEP on this platform. Uninsert the breakpoint,
- mark it for reinsertion, and single-step.
-
- Otherwise, call the target function to figure out where we need
- our temporary breakpoint, create it, and continue executing this
- process. */
+ if (step_over_finished)
+ unstop_all_lwps (event_child);
- /* NOTE: we're lifting breakpoints in non-stop mode. This
- is currently only used for thread event breakpoints, so
- it isn't that bad as long as we have PTRACE_EVENT_CLONE
- events. */
- if (bp_status == 2)
- /* No need to reinsert. */
- linux_resume_one_lwp (event_child, 0, 0, NULL);
- else if (the_low_target.breakpoint_reinsert_addr == NULL)
+ if (debug_threads)
{
- event_child->bp_reinsert = stop_pc;
- uninsert_breakpoint (stop_pc);
- linux_resume_one_lwp (event_child, 1, 0, NULL);
+ if (event_child->last_resume_kind == resume_step)
+ fprintf (stderr, "GDB wanted to single-step, reporting event.\n");
+ if (event_child->stopped_by_watchpoint)
+ fprintf (stderr, "Stopped by watchpoint.\n");
}
- else
+ }
+ /* We found no reason GDB would want us to stop. We either hit
+ one of our own breakpoints, or finished an internal step GDB
+ shouldn't know about. */
+ else if (step_over_finished || bp_explains_trap)
+ {
+ if (debug_threads)
{
- reinsert_breakpoint_by_bp
- (stop_pc, (*the_low_target.breakpoint_reinsert_addr) ());
- linux_resume_one_lwp (event_child, 0, 0, NULL);
+ if (bp_explains_trap)
+ fprintf (stderr, "Hit a gdbserver breakpoint.\n");
+ if (step_over_finished)
+ fprintf (stderr, "Step-over finished.\n");
}
- continue;
- }
+ /* If we stepped or ran into an internal breakpoint, we've
+ already handled it. So next time we resume (from this
+ PC), we should step over it. */
+ if (breakpoint_here (stop_pc))
+ event_child->need_step_over = 1;
- if (debug_threads)
- fprintf (stderr, "Hit a non-gdbserver breakpoint.\n");
-
- /* If we were single-stepping, we definitely want to report the
- SIGTRAP. Although the single-step operation has completed,
- do not clear clear the stepping flag yet; we need to check it
- in wait_for_sigstop. */
- if (event_child->stepping)
- return lwpid_of (event_child);
-
- /* A SIGTRAP that we can't explain. It may have been a breakpoint.
- Check if it is a breakpoint, and if so mark the process information
- accordingly. This will handle both the necessary fiddling with the
- PC on decr_pc_after_break targets and suppressing extra threads
- hitting a breakpoint if two hit it at once and then GDB removes it
- after the first is reported. Arguably it would be better to report
- multiple threads hitting breakpoints simultaneously, but the current
- remote protocol does not allow this. */
- if ((*the_low_target.breakpoint_at) (stop_pc))
+ /* We're not reporting this breakpoint to GDB, so apply the
+ decr_pc_after_break adjustment to the inferior's regcache
+ ourselves. */
+
+ if (the_low_target.set_pc != NULL)
+ {
+ struct regcache *regcache
+ = get_thread_regcache (get_lwp_thread (event_child), 1);
+ (*the_low_target.set_pc) (regcache, stop_pc);
+ }
+
+ /* We've finished stepping over a breakpoint. We've stopped
+ all LWPs momentarily except the stepping one. This is
+ where we resume them all again. We're going to keep
+ waiting, so use proceed, which handles stepping over the
+ next breakpoint. */
+ if (debug_threads)
+ fprintf (stderr, "proceeding all threads.\n");
+ proceed_all_lwps ();
+
+ /* If we stopped threads momentarily, we may have threads
+ with pending statuses now (except when we're going to
+ force the next event out of a specific LWP, in which case
+ don't want to handle the pending events of other LWPs
+ yet. */
+ if (ptid_equal (step_over_bkpt, null_ptid))
+ goto again;
+ else
+ continue;
+ }
+ else
{
- event_child->pending_is_breakpoint = 1;
- event_child->pending_stop_pc = stop_pc;
+ /* GDB breakpoint or program trap, perhaps. */
+ if (step_over_finished)
+ unstop_all_lwps (event_child);
}
+ if (debug_threads)
+ fprintf (stderr, "Hit a non-gdbserver trap event.\n");
+
return lwpid_of (event_child);
}
}
}
+/* Set this inferior LWP's state as "want-stopped". We won't resume
+ this LWP until the client gives us another action for it. */
+
+static void
+gdb_wants_lwp_stopped (struct inferior_list_entry *entry)
+{
+ struct lwp_info *lwp = (struct lwp_info *) entry;
+ struct thread_info *thread = get_lwp_thread (lwp);
+
+ /* Most threads are stopped implicitly (all-stop); tag that with
+ signal 0. The thread being explicitly reported stopped to the
+ client, gets it's status fixed up afterwards. */
+ thread->last_status.kind = TARGET_WAITKIND_STOPPED;
+ thread->last_status.value.sig = TARGET_SIGNAL_0;
+
+ lwp->last_resume_kind = resume_stop;
+}
+
+/* Set all LWP's states as "want-stopped". */
+
+static void
+gdb_wants_all_stopped (void)
+{
+ for_each_inferior (&all_lwps, gdb_wants_lwp_stopped);
+}
+
/* Wait for process, returns status. */
static ptid_t
goto retry;
}
- /* In all-stop, stop all threads. Be careful to only do this if
- we're about to report an event to GDB. */
- if (!non_stop)
- stop_all_lwps ();
-
ourstatus->kind = TARGET_WAITKIND_STOPPED;
- if (lwp->suspended && WSTOPSIG (w) == SIGSTOP)
+ /* Do this before the gdb_wants_all_stopped calls below, since they
+ always set last_resume_kind to resume_stop. */
+ if (lwp->last_resume_kind == resume_stop && WSTOPSIG (w) == SIGSTOP)
{
/* A thread that has been requested to stop by GDB with vCont;t,
and it stopped cleanly, so report as SIG0. The use of
SIGSTOP is an implementation detail. */
ourstatus->value.sig = TARGET_SIGNAL_0;
}
- else if (lwp->suspended && WSTOPSIG (w) != SIGSTOP)
+ else if (lwp->last_resume_kind == resume_stop && WSTOPSIG (w) != SIGSTOP)
{
/* A thread that has been requested to stop by GDB with vCont;t,
- but, it stopped for other reasons. Set stop_expected so the
- pending SIGSTOP is ignored and the LWP is resumed. */
- lwp->stop_expected = 1;
+ but, it stopped for other reasons. */
ourstatus->value.sig = target_signal_from_host (WSTOPSIG (w));
}
else
ourstatus->value.sig = target_signal_from_host (WSTOPSIG (w));
}
+ gdb_assert (ptid_equal (step_over_bkpt, null_ptid));
+
+ if (!non_stop)
+ {
+ /* In all-stop, stop all threads, we're about to report an event
+ to GDB. */
+ stop_all_lwps ();
+
+ /* Do not leave a pending single-step finish to be reported to
+ the client. The client will give us a new action for this
+ thread, possibly a continue request --- otherwise, the client
+ would consider this pending SIGTRAP reported later a spurious
+ signal. */
+ cancel_finished_single_steps (lwp);
+
+ /* From GDB's perspective, all-stop mode always stops all
+ threads implicitly. Tag all threads as "want-stopped". */
+ gdb_wants_all_stopped ();
+ }
+ else
+ {
+ /* We're reporting this LWP as stopped. Update it's
+ "want-stopped" state to what the client wants, until it gets
+ a new resume action. */
+ gdb_wants_lwp_stopped (&lwp->head);
+ }
+
if (debug_threads)
fprintf (stderr, "linux_wait ret = %s, %d, %d\n",
target_pid_to_str (lwp->head.id),
ourstatus->kind,
ourstatus->value.sig);
+ get_lwp_thread (lwp)->last_status = *ourstatus;
return lwp->head.id;
}
if (debug_threads)
fprintf (stderr, "Have pending sigstop for lwp %d\n", pid);
- /* We clear the stop_expected flag so that wait_for_sigstop
- will receive the SIGSTOP event (instead of silently resuming and
- waiting again). It'll be reset below. */
- lwp->stop_expected = 0;
return;
}
if (debug_threads)
fprintf (stderr, "Sending sigstop to lwp %d\n", pid);
+ lwp->stop_expected = 1;
kill_lwp (pid, SIGSTOP);
}
lwp->status_pending_p = 1;
lwp->status_pending = wstat;
- /* So that check_removed_breakpoint doesn't try to figure out if
- this is stopped at a breakpoint. */
- lwp->pending_is_breakpoint = 0;
-
/* Prevent trying to stop it. */
lwp->stopped = 1;
lwp->stop_expected = 0;
}
+static int
+cancel_finished_single_step (struct inferior_list_entry *entry, void *except)
+{
+ struct lwp_info *lwp = (struct lwp_info *) entry;
+ struct thread_info *saved_inferior;
+
+ if (lwp == except)
+ return 0;
+
+ saved_inferior = current_inferior;
+ current_inferior = get_lwp_thread (lwp);
+
+ /* Do not leave a pending single-step finish to be reported to the
+ client. The client will give us a new action for this thread,
+ possibly a continue request --- otherwise, the client would
+ consider this pending SIGTRAP reported later a spurious
+ signal. */
+ if (lwp->status_pending_p
+ && WSTOPSIG (lwp->status_pending) == SIGTRAP
+ && lwp->stepping
+ && !lwp->stopped_by_watchpoint)
+ {
+ if (debug_threads)
+ fprintf (stderr, " single-step SIGTRAP cancelled\n");
+
+ lwp->status_pending_p = 0;
+ lwp->status_pending = 0;
+ }
+
+ current_inferior = saved_inferior;
+ return 0;
+}
+
+static void
+cancel_finished_single_steps (struct lwp_info *except)
+{
+ find_inferior (&all_lwps, cancel_finished_single_step, except);
+}
+
static void
wait_for_sigstop (struct inferior_list_entry *entry)
{
int wstat;
ptid_t saved_tid;
ptid_t ptid;
+ int pid;
if (lwp->stopped)
- return;
+ {
+ if (debug_threads)
+ fprintf (stderr, "wait_for_sigstop: LWP %ld already stopped\n",
+ lwpid_of (lwp));
+ return;
+ }
saved_inferior = current_inferior;
if (saved_inferior != NULL)
ptid = lwp->head.id;
- linux_wait_for_event (ptid, &wstat, __WALL);
+ if (debug_threads)
+ fprintf (stderr, "wait_for_sigstop: pulling one event\n");
+
+ pid = linux_wait_for_event (ptid, &wstat, __WALL);
/* If we stopped with a non-SIGSTOP signal, save it for later
and record the pending SIGSTOP. If the process exited, just
return. */
- if (WIFSTOPPED (wstat)
- && WSTOPSIG (wstat) != SIGSTOP)
+ if (WIFSTOPPED (wstat))
{
if (debug_threads)
- fprintf (stderr, "LWP %ld stopped with non-sigstop status %06x\n",
- lwpid_of (lwp), wstat);
+ fprintf (stderr, "LWP %ld stopped with signal %d\n",
+ lwpid_of (lwp), WSTOPSIG (wstat));
- /* Do not leave a pending single-step finish to be reported to
- the client. The client will give us a new action for this
- thread, possibly a continue request --- otherwise, the client
- would consider this pending SIGTRAP reported later a spurious
- signal. */
- if (WSTOPSIG (wstat) == SIGTRAP
- && lwp->stepping
- && !lwp->stopped_by_watchpoint)
+ if (WSTOPSIG (wstat) != SIGSTOP)
{
if (debug_threads)
- fprintf (stderr, " single-step SIGTRAP ignored\n");
- }
- else
- {
+ fprintf (stderr, "LWP %ld stopped with non-sigstop status %06x\n",
+ lwpid_of (lwp), wstat);
+
lwp->status_pending_p = 1;
lwp->status_pending = wstat;
}
- lwp->stop_expected = 1;
}
- else if (!WIFSTOPPED (wstat))
+ else
{
if (debug_threads)
- fprintf (stderr, "Process %ld exited while stopping LWPs\n",
- lwpid_of (lwp));
+ fprintf (stderr, "Process %d exited while stopping LWPs\n", pid);
- /* Leave this status pending for the next time we're able to
- report it. In the mean time, we'll report this lwp as dead
- to GDB, so GDB doesn't try to read registers and memory from
- it. */
- mark_lwp_dead (lwp, wstat);
+ lwp = find_lwp_pid (pid_to_ptid (pid));
+ if (lwp)
+ {
+ /* Leave this status pending for the next time we're able to
+ report it. In the mean time, we'll report this lwp as
+ dead to GDB, so GDB doesn't try to read registers and
+ memory from it. This can only happen if this was the
+ last thread of the process; otherwise, PID is removed
+ from the thread tables before linux_wait_for_event
+ returns. */
+ mark_lwp_dead (lwp, wstat);
+ }
}
if (saved_inferior == NULL || linux_thread_alive (saved_tid))
lwp->pending_signals = p_sig;
}
- if (lwp->status_pending_p && !check_removed_breakpoint (lwp))
- return;
+ if (lwp->status_pending_p)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Not resuming lwp %ld (%s, signal %d, stop %s);"
+ " has pending status\n",
+ lwpid_of (lwp), step ? "step" : "continue", signal,
+ lwp->stop_expected ? "expected" : "not expected");
+ return;
+ }
saved_inferior = current_inferior;
current_inferior = get_lwp_thread (lwp);
if (lwp->bp_reinsert != 0)
{
if (debug_threads)
- fprintf (stderr, " pending reinsert at %08lx", (long)lwp->bp_reinsert);
- if (step == 0)
- fprintf (stderr, "BAD - reinserting but not stepping.\n");
- step = 1;
+ fprintf (stderr, " pending reinsert at 0x%s\n",
+ paddress (lwp->bp_reinsert));
+
+ if (lwp->bp_reinsert != 0 && can_hardware_single_step ())
+ {
+ if (step == 0)
+ fprintf (stderr, "BAD - reinserting but not stepping.\n");
+
+ step = 1;
+ }
/* Postpone any pending signal. It was enqueued above. */
signal = 0;
}
- check_removed_breakpoint (lwp);
-
if (debug_threads && the_low_target.get_pc != NULL)
{
struct regcache *regcache = get_thread_regcache (current_inferior, 1);
|| (ptid_get_lwp (ptid) == -1
&& (ptid_get_pid (ptid) == pid_of (lwp))))
{
+ if (r->resume[ndx].kind == resume_stop
+ && lwp->last_resume_kind == resume_stop)
+ {
+ if (debug_threads)
+ fprintf (stderr, "already %s LWP %ld at GDB's request\n",
+ thread->last_status.kind == TARGET_WAITKIND_STOPPED
+ ? "stopped"
+ : "stopping",
+ lwpid_of (lwp));
+
+ continue;
+ }
+
lwp->resume = &r->resume[ndx];
+ lwp->last_resume_kind = lwp->resume->kind;
return 0;
}
}
if (lwp->resume == NULL)
return 0;
- /* If this thread has a removed breakpoint, we won't have any
- events to report later, so check now. check_removed_breakpoint
- may clear status_pending_p. We avoid calling check_removed_breakpoint
- for any thread that we are not otherwise going to resume - this
- lets us preserve stopped status when two threads hit a breakpoint.
- GDB removes the breakpoint to single-step a particular thread
- past it, then re-inserts it and resumes all threads. We want
- to report the second thread without resuming it in the interim. */
if (lwp->status_pending_p)
- check_removed_breakpoint (lwp);
+ * (int *) flag_p = 1;
+
+ return 0;
+}
+
+/* Return 1 if this lwp that GDB wants running is stopped at an
+ internal breakpoint that we need to step over. It assumes that any
+ required STOP_PC adjustment has already been propagated to the
+ inferior's regcache. */
+
+static int
+need_step_over_p (struct inferior_list_entry *entry, void *dummy)
+{
+ struct lwp_info *lwp = (struct lwp_info *) entry;
+ struct thread_info *saved_inferior;
+ CORE_ADDR pc;
+
+ /* LWPs which will not be resumed are not interesting, because we
+ might not wait for them next time through linux_wait. */
+
+ if (!lwp->stopped)
+ {
+ if (debug_threads)
+ fprintf (stderr,
+ "Need step over [LWP %ld]? Ignoring, not stopped\n",
+ lwpid_of (lwp));
+ return 0;
+ }
+
+ if (lwp->last_resume_kind == resume_stop)
+ {
+ if (debug_threads)
+ fprintf (stderr,
+ "Need step over [LWP %ld]? Ignoring, should remain stopped\n",
+ lwpid_of (lwp));
+ return 0;
+ }
+
+ if (!lwp->need_step_over)
+ {
+ if (debug_threads)
+ fprintf (stderr,
+ "Need step over [LWP %ld]? No\n", lwpid_of (lwp));
+ }
if (lwp->status_pending_p)
- * (int *) flag_p = 1;
+ {
+ if (debug_threads)
+ fprintf (stderr,
+ "Need step over [LWP %ld]? Ignoring, has pending status.\n",
+ lwpid_of (lwp));
+ return 0;
+ }
+
+ /* Note: PC, not STOP_PC. Either GDB has adjusted the PC already,
+ or we have. */
+ pc = get_pc (lwp);
+
+ /* If the PC has changed since we stopped, then don't do anything,
+ and let the breakpoint/tracepoint be hit. This happens if, for
+ instance, GDB handled the decr_pc_after_break subtraction itself,
+ GDB is OOL stepping this thread, or the user has issued a "jump"
+ command, or poked thread's registers herself. */
+ if (pc != lwp->stop_pc)
+ {
+ if (debug_threads)
+ fprintf (stderr,
+ "Need step over [LWP %ld]? Cancelling, PC was changed. "
+ "Old stop_pc was 0x%s, PC is now 0x%s\n",
+ lwpid_of (lwp), paddress (lwp->stop_pc), paddress (pc));
+
+ lwp->need_step_over = 0;
+ return 0;
+ }
+
+ saved_inferior = current_inferior;
+ current_inferior = get_lwp_thread (lwp);
+
+ /* We only step over our breakpoints. */
+ if (breakpoint_here (pc))
+ {
+ if (debug_threads)
+ fprintf (stderr,
+ "Need step over [LWP %ld]? yes, found breakpoint at 0x%s\n",
+ lwpid_of (lwp), paddress (pc));
+
+ /* We've found an lwp that needs stepping over --- return 1 so
+ that find_inferior stops looking. */
+ current_inferior = saved_inferior;
+
+ /* If the step over is cancelled, this is set again. */
+ lwp->need_step_over = 0;
+ return 1;
+ }
+
+ current_inferior = saved_inferior;
+
+ if (debug_threads)
+ fprintf (stderr,
+ "Need step over [LWP %ld]? No, no breakpoint found at 0x%s\n",
+ lwpid_of (lwp), paddress (pc));
return 0;
}
+/* Start a step-over operation on LWP. When LWP stopped at a
+ breakpoint, to make progress, we need to remove the breakpoint out
+ of the way. If we let other threads run while we do that, they may
+ pass by the breakpoint location and miss hitting it. To avoid
+ that, a step-over momentarily stops all threads while LWP is
+ single-stepped while the breakpoint is temporarily uninserted from
+ the inferior. When the single-step finishes, we reinsert the
+ breakpoint, and let all threads that are supposed to be running,
+ run again.
+
+ On targets that don't support hardware single-step, we don't
+ currently support full software single-stepping. Instead, we only
+ support stepping over the thread event breakpoint, by asking the
+ low target where to place a reinsert breakpoint. Since this
+ routine assumes the breakpoint being stepped over is a thread event
+ breakpoint, it usually assumes the return address of the current
+ function is a good enough place to set the reinsert breakpoint. */
+
+static int
+start_step_over (struct lwp_info *lwp)
+{
+ struct thread_info *saved_inferior;
+ CORE_ADDR pc;
+ int step;
+
+ if (debug_threads)
+ fprintf (stderr,
+ "Starting step-over on LWP %ld. Stopping all threads\n",
+ lwpid_of (lwp));
+
+ stop_all_lwps ();
+
+ if (debug_threads)
+ fprintf (stderr, "Done stopping all threads for step-over.\n");
+
+ /* Note, we should always reach here with an already adjusted PC,
+ either by GDB (if we're resuming due to GDB's request), or by our
+ caller, if we just finished handling an internal breakpoint GDB
+ shouldn't care about. */
+ pc = get_pc (lwp);
+
+ saved_inferior = current_inferior;
+ current_inferior = get_lwp_thread (lwp);
+
+ lwp->bp_reinsert = pc;
+ uninsert_breakpoints_at (pc);
+
+ if (can_hardware_single_step ())
+ {
+ step = 1;
+ }
+ else
+ {
+ CORE_ADDR raddr = (*the_low_target.breakpoint_reinsert_addr) ();
+ set_reinsert_breakpoint (raddr);
+ step = 0;
+ }
+
+ current_inferior = saved_inferior;
+
+ linux_resume_one_lwp (lwp, step, 0, NULL);
+
+ /* Require next event from this LWP. */
+ step_over_bkpt = lwp->head.id;
+ return 1;
+}
+
+/* Finish a step-over. Reinsert the breakpoint we had uninserted in
+ start_step_over, if still there, and delete any reinsert
+ breakpoints we've set, on non hardware single-step targets. */
+
+static int
+finish_step_over (struct lwp_info *lwp)
+{
+ if (lwp->bp_reinsert != 0)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Finished step over.\n");
+
+ /* Reinsert any breakpoint at LWP->BP_REINSERT. Note that there
+ may be no breakpoint to reinsert there by now. */
+ reinsert_breakpoints_at (lwp->bp_reinsert);
+
+ lwp->bp_reinsert = 0;
+
+ /* Delete any software-single-step reinsert breakpoints. No
+ longer needed. We don't have to worry about other threads
+ hitting this trap, and later not being able to explain it,
+ because we were stepping over a breakpoint, and we hold all
+ threads but LWP stopped while doing that. */
+ if (!can_hardware_single_step ())
+ delete_reinsert_breakpoints ();
+
+ step_over_bkpt = null_ptid;
+ return 1;
+ }
+ else
+ return 0;
+}
+
/* This function is called once per thread. We check the thread's resume
request, which will tell us whether to resume, step, or leave the thread
stopped; and what signal, if any, it should be sent.
struct lwp_info *lwp;
struct thread_info *thread;
int step;
- int pending_flag = * (int *) arg;
+ int leave_all_stopped = * (int *) arg;
+ int leave_pending;
thread = (struct thread_info *) entry;
lwp = get_thread_lwp (thread);
if (lwp->resume->kind == resume_stop)
{
if (debug_threads)
- fprintf (stderr, "suspending LWP %ld\n", lwpid_of (lwp));
+ fprintf (stderr, "resume_stop request for LWP %ld\n", lwpid_of (lwp));
if (!lwp->stopped)
{
if (debug_threads)
- fprintf (stderr, "running -> suspending LWP %ld\n", lwpid_of (lwp));
+ fprintf (stderr, "stopping LWP %ld\n", lwpid_of (lwp));
- lwp->suspended = 1;
+ /* Stop the thread, and wait for the event asynchronously,
+ through the event loop. */
send_sigstop (&lwp->head);
}
else
{
if (debug_threads)
- {
- if (lwp->suspended)
- fprintf (stderr, "already stopped/suspended LWP %ld\n",
- lwpid_of (lwp));
- else
- fprintf (stderr, "already stopped/not suspended LWP %ld\n",
- lwpid_of (lwp));
- }
-
- /* Make sure we leave the LWP suspended, so we don't try to
- resume it without GDB telling us to. FIXME: The LWP may
- have been stopped in an internal event that was not meant
- to be notified back to GDB (e.g., gdbserver breakpoint),
- so we should be reporting a stop event in that case
- too. */
- lwp->suspended = 1;
+ fprintf (stderr, "already stopped LWP %ld\n",
+ lwpid_of (lwp));
+
+ /* The LWP may have been stopped in an internal event that
+ was not meant to be notified back to GDB (e.g., gdbserver
+ breakpoint), so we should be reporting a stop event in
+ this case too. */
+
+ /* If the thread already has a pending SIGSTOP, this is a
+ no-op. Otherwise, something later will presumably resume
+ the thread and this will cause it to cancel any pending
+ operation, due to last_resume_kind == resume_stop. If
+ the thread already has a pending status to report, we
+ will still report it the next time we wait - see
+ status_pending_p_callback. */
+ send_sigstop (&lwp->head);
}
/* For stop requests, we're done. */
lwp->resume = NULL;
+ get_lwp_thread (lwp)->last_status.kind = TARGET_WAITKIND_IGNORE;
return 0;
}
- else
- lwp->suspended = 0;
/* If this thread which is about to be resumed has a pending status,
then don't resume any threads - we can just report the pending
status. Make sure to queue any signals that would otherwise be
sent. In all-stop mode, we do this decision based on if *any*
- thread has a pending status. */
- if (non_stop)
- resume_status_pending_p (&lwp->head, &pending_flag);
+ thread has a pending status. If there's a thread that needs the
+ step-over-breakpoint dance, then don't resume any other thread
+ but that particular one. */
+ leave_pending = (lwp->status_pending_p || leave_all_stopped);
- if (!pending_flag)
+ if (!leave_pending)
{
if (debug_threads)
fprintf (stderr, "resuming LWP %ld\n", lwpid_of (lwp));
- if (ptid_equal (lwp->resume->thread, minus_one_ptid)
- && lwp->stepping
- && lwp->pending_is_breakpoint)
- step = 1;
- else
- step = (lwp->resume->kind == resume_step);
-
+ step = (lwp->resume->kind == resume_step);
linux_resume_one_lwp (lwp, step, lwp->resume->sig, NULL);
+ get_lwp_thread (lwp)->last_status.kind = TARGET_WAITKIND_IGNORE;
}
else
{
static void
linux_resume (struct thread_resume *resume_info, size_t n)
{
- int pending_flag;
struct thread_resume_array array = { resume_info, n };
+ struct lwp_info *need_step_over = NULL;
+ int any_pending;
+ int leave_all_stopped;
find_inferior (&all_threads, linux_set_resume_request, &array);
- /* If there is a thread which would otherwise be resumed, which
- has a pending status, then don't resume any threads - we can just
- report the pending status. Make sure to queue any signals
- that would otherwise be sent. In non-stop mode, we'll apply this
- logic to each thread individually. */
- pending_flag = 0;
+ /* If there is a thread which would otherwise be resumed, which has
+ a pending status, then don't resume any threads - we can just
+ report the pending status. Make sure to queue any signals that
+ would otherwise be sent. In non-stop mode, we'll apply this
+ logic to each thread individually. We consume all pending events
+ before considering to start a step-over (in all-stop). */
+ any_pending = 0;
if (!non_stop)
- find_inferior (&all_lwps, resume_status_pending_p, &pending_flag);
+ find_inferior (&all_lwps, resume_status_pending_p, &any_pending);
+
+ /* If there is a thread which would otherwise be resumed, which is
+ stopped at a breakpoint that needs stepping over, then don't
+ resume any threads - have it step over the breakpoint with all
+ other threads stopped, then resume all threads again. Make sure
+ to queue any signals that would otherwise be delivered or
+ queued. */
+ if (!any_pending && supports_breakpoints ())
+ need_step_over
+ = (struct lwp_info *) find_inferior (&all_lwps,
+ need_step_over_p, NULL);
+
+ leave_all_stopped = (need_step_over != NULL || any_pending);
if (debug_threads)
{
- if (pending_flag)
- fprintf (stderr, "Not resuming, pending status\n");
+ if (need_step_over != NULL)
+ fprintf (stderr, "Not resuming all, need step over\n");
+ else if (any_pending)
+ fprintf (stderr,
+ "Not resuming, all-stop and found "
+ "an LWP with pending status\n");
else
- fprintf (stderr, "Resuming, no pending status\n");
+ fprintf (stderr, "Resuming, no pending status or step over needed\n");
}
- find_inferior (&all_threads, linux_resume_one_thread, &pending_flag);
+ /* Even if we're leaving threads stopped, queue all signals we'd
+ otherwise deliver. */
+ find_inferior (&all_threads, linux_resume_one_thread, &leave_all_stopped);
+
+ if (need_step_over)
+ start_step_over (need_step_over);
+}
+
+/* This function is called once per thread. We check the thread's
+ last resume request, which will tell us whether to resume, step, or
+ leave the thread stopped. Any signal the client requested to be
+ delivered has already been enqueued at this point.
+
+ If any thread that GDB wants running is stopped at an internal
+ breakpoint that needs stepping over, we start a step-over operation
+ on that particular thread, and leave all others stopped. */
+
+static void
+proceed_one_lwp (struct inferior_list_entry *entry)
+{
+ struct lwp_info *lwp;
+ int step;
+
+ lwp = (struct lwp_info *) entry;
+
+ if (debug_threads)
+ fprintf (stderr,
+ "proceed_one_lwp: lwp %ld\n", lwpid_of (lwp));
+
+ if (!lwp->stopped)
+ {
+ if (debug_threads)
+ fprintf (stderr, " LWP %ld already running\n", lwpid_of (lwp));
+ return;
+ }
+
+ if (lwp->last_resume_kind == resume_stop)
+ {
+ if (debug_threads)
+ fprintf (stderr, " client wants LWP %ld stopped\n", lwpid_of (lwp));
+ return;
+ }
+
+ if (lwp->status_pending_p)
+ {
+ if (debug_threads)
+ fprintf (stderr, " LWP %ld has pending status, leaving stopped\n",
+ lwpid_of (lwp));
+ return;
+ }
+
+ if (lwp->suspended)
+ {
+ if (debug_threads)
+ fprintf (stderr, " LWP %ld is suspended\n", lwpid_of (lwp));
+ return;
+ }
+
+ step = lwp->last_resume_kind == resume_step;
+ linux_resume_one_lwp (lwp, step, 0, NULL);
+}
+
+/* When we finish a step-over, set threads running again. If there's
+ another thread that may need a step-over, now's the time to start
+ it. Eventually, we'll move all threads past their breakpoints. */
+
+static void
+proceed_all_lwps (void)
+{
+ struct lwp_info *need_step_over;
+
+ /* If there is a thread which would otherwise be resumed, which is
+ stopped at a breakpoint that needs stepping over, then don't
+ resume any threads - have it step over the breakpoint with all
+ other threads stopped, then resume all threads again. */
+
+ if (supports_breakpoints ())
+ {
+ need_step_over
+ = (struct lwp_info *) find_inferior (&all_lwps,
+ need_step_over_p, NULL);
+
+ if (need_step_over != NULL)
+ {
+ if (debug_threads)
+ fprintf (stderr, "proceed_all_lwps: found "
+ "thread %ld needing a step-over\n",
+ lwpid_of (need_step_over));
+
+ start_step_over (need_step_over);
+ return;
+ }
+ }
+
+ if (debug_threads)
+ fprintf (stderr, "Proceeding, no step-over needed\n");
+
+ for_each_inferior (&all_lwps, proceed_one_lwp);
+}
+
+/* Stopped LWPs that the client wanted to be running, that don't have
+ pending statuses, are set to run again, except for EXCEPT, if not
+ NULL. This undoes a stop_all_lwps call. */
+
+static void
+unstop_all_lwps (struct lwp_info *except)
+{
+ if (debug_threads)
+ {
+ if (except)
+ fprintf (stderr,
+ "unstopping all lwps, except=(LWP %ld)\n", lwpid_of (except));
+ else
+ fprintf (stderr,
+ "unstopping all lwps\n");
+ }
+
+ /* Make sure proceed_one_lwp doesn't try to resume this thread. */
+ if (except != NULL)
+ ++except->suspended;
+
+ for_each_inferior (&all_lwps, proceed_one_lwp);
+
+ if (except != NULL)
+ --except->suspended;
}
#ifdef HAVE_LINUX_USRREGS
projects / binutils-gdb.git / commitdiff