/* This is set to the data address of the access causing the target
to stop for a watchpoint. */
CORE_ADDR watch_data_address;
+
+ /* Fields used by the vCont action coalescing implemented in
+ remote_resume / remote_commit_resume. remote_resume stores each
+ thread's last resume request in these fields, so that a later
+ remote_commit_resume knows which is the proper action for this
+ thread to include in the vCont packet. */
+
+ /* True if the last target_resume call for this thread was a step
+ request, false if a continue request. */
+ int last_resume_step;
+
+ /* The signal specified in the last target_resume call for this
+ thread. */
+ enum gdb_signal last_resume_sig;
+
+ /* Whether this thread was already vCont-resumed on the remote
+ side. */
+ int vcont_resumed;
};
static void
return inf;
}
+static struct private_thread_info *
+ get_private_info_thread (struct thread_info *info);
+
/* Add thread PTID to GDB's thread list. Tag it as executing/running
according to RUNNING. */
remote_add_thread (ptid_t ptid, int running, int executing)
{
struct remote_state *rs = get_remote_state ();
+ struct thread_info *thread;
/* GDB historically didn't pull threads in the initial connection
setup. If the remote target doesn't even have a concept of
might be confusing to the user. Be silent then, preserving the
age old behavior. */
if (rs->starting_up)
- add_thread_silent (ptid);
+ thread = add_thread_silent (ptid);
else
- add_thread (ptid);
+ thread = add_thread (ptid);
+ get_private_info_thread (thread)->vcont_resumed = executing;
set_executing (ptid, executing);
set_running (ptid, running);
}
}
}
-/* Return the private thread data, creating it if necessary. */
+/* Return THREAD's private thread data, creating it if necessary. */
static struct private_thread_info *
-demand_private_info (ptid_t ptid)
+get_private_info_thread (struct thread_info *thread)
{
- struct thread_info *info = find_thread_ptid (ptid);
+ gdb_assert (thread != NULL);
- gdb_assert (info);
-
- if (!info->priv)
+ if (thread->priv == NULL)
{
- info->priv = XNEW (struct private_thread_info);
- info->private_dtor = free_private_thread_info;
- info->priv->core = -1;
- info->priv->extra = NULL;
- info->priv->name = NULL;
+ struct private_thread_info *priv = XNEW (struct private_thread_info);
+
+ thread->private_dtor = free_private_thread_info;
+ thread->priv = priv;
+
+ priv->core = -1;
+ priv->extra = NULL;
+ priv->name = NULL;
+ priv->name = NULL;
+ priv->last_resume_step = 0;
+ priv->last_resume_sig = GDB_SIGNAL_0;
+ priv->vcont_resumed = 0;
}
- return info->priv;
+ return thread->priv;
+}
+
+/* Return PTID's private thread data, creating it if necessary. */
+
+static struct private_thread_info *
+get_private_info_ptid (ptid_t ptid)
+{
+ struct thread_info *info = find_thread_ptid (ptid);
+
+ return get_private_info_thread (info);
}
/* Call this function as a result of
remote_notice_new_inferior (item->ptid, executing);
- info = demand_private_info (item->ptid);
+ info = get_private_info_ptid (item->ptid);
info->core = item->core;
info->extra = item->extra;
item->extra = NULL;
set_executing (event_ptid, 0);
set_running (event_ptid, 0);
+ thread->priv->vcont_resumed = 0;
}
/* "Notice" the new inferiors before anything related to
{
struct remote_state *rs = get_remote_state ();
+ /* When connected in non-stop mode, the core resumes threads
+ individually. Resuming remote threads directly in target_resume
+ would thus result in sending one packet per thread. Instead, to
+ minimize roundtrip latency, here we just store the resume
+ request; the actual remote resumption will be done in
+ target_commit_resume / remote_commit_resume, where we'll be able
+ to do vCont action coalescing. */
+ if (target_is_non_stop_p () && execution_direction != EXEC_REVERSE)
+ {
+ struct private_thread_info *remote_thr;
+
+ if (ptid_equal (minus_one_ptid, ptid) || ptid_is_pid (ptid))
+ remote_thr = get_private_info_ptid (inferior_ptid);
+ else
+ remote_thr = get_private_info_ptid (ptid);
+ remote_thr->last_resume_step = step;
+ remote_thr->last_resume_sig = siggnal;
+ return;
+ }
+
/* In all-stop, we can't mark REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN
(explained in remote-notif.c:handle_notification) so
remote_notif_process is not called. We need find a place where
if (!target_is_non_stop_p ())
rs->waiting_for_stop_reply = 1;
}
+
+static void check_pending_events_prevent_wildcard_vcont
+ (int *may_global_wildcard_vcont);
+static int is_pending_fork_parent_thread (struct thread_info *thread);
+
+/* Private per-inferior info for target remote processes. */
+
+struct private_inferior
+{
+ /* Whether we can send a wildcard vCont for this process. */
+ int may_wildcard_vcont;
+};
+
+/* Structure used to track the construction of a vCont packet in the
+ outgoing packet buffer. This is used to send multiple vCont
+ packets if we have more actions than would fit a single packet. */
+
+struct vcont_builder
+{
+ /* Pointer to the first action. P points here if no action has been
+ appended yet. */
+ char *first_action;
+
+ /* Where the next action will be appended. */
+ char *p;
+
+ /* The end of the buffer. Must never write past this. */
+ char *endp;
+};
+
+/* Prepare the outgoing buffer for a new vCont packet. */
+
+static void
+vcont_builder_restart (struct vcont_builder *builder)
+{
+ struct remote_state *rs = get_remote_state ();
+
+ builder->p = rs->buf;
+ builder->endp = rs->buf + get_remote_packet_size ();
+ builder->p += xsnprintf (builder->p, builder->endp - builder->p, "vCont");
+ builder->first_action = builder->p;
+}
+
+/* If the vCont packet being built has any action, send it to the
+ remote end. */
+
+static void
+vcont_builder_flush (struct vcont_builder *builder)
+{
+ struct remote_state *rs;
+
+ if (builder->p == builder->first_action)
+ return;
+
+ rs = get_remote_state ();
+ putpkt (rs->buf);
+ getpkt (&rs->buf, &rs->buf_size, 0);
+ if (strcmp (rs->buf, "OK") != 0)
+ error (_("Unexpected vCont reply in non-stop mode: %s"), rs->buf);
+}
+
+/* The largest action is range-stepping, with its two addresses. This
+ is more than sufficient. If a new, bigger action is created, it'll
+ quickly trigger a failed assertion in append_resumption (and we'll
+ just bump this). */
+#define MAX_ACTION_SIZE 200
+
+/* Append a new vCont action in the outgoing packet being built. If
+ the action doesn't fit the packet along with previous actions, push
+ what we've got so far to the remote end and start over a new vCont
+ packet (with the new action). */
+
+static void
+vcont_builder_push_action (struct vcont_builder *builder,
+ ptid_t ptid, int step, enum gdb_signal siggnal)
+{
+ char buf[MAX_ACTION_SIZE + 1];
+ char *endp;
+ size_t rsize;
+
+ endp = append_resumption (buf, buf + sizeof (buf),
+ ptid, step, siggnal);
+
+ /* Check whether this new action would fit in the vCont packet along
+ with previous actions. If not, send what we've got so far and
+ start a new vCont packet. */
+ rsize = endp - buf;
+ if (rsize > builder->endp - builder->p)
+ {
+ vcont_builder_flush (builder);
+ vcont_builder_restart (builder);
+
+ /* Should now fit. */
+ gdb_assert (rsize <= builder->endp - builder->p);
+ }
+
+ memcpy (builder->p, buf, rsize);
+ builder->p += rsize;
+ *builder->p = '\0';
+}
+
+/* to_commit_resume implementation. */
+
+static void
+remote_commit_resume (struct target_ops *ops)
+{
+ struct remote_state *rs = get_remote_state ();
+ struct inferior *inf;
+ struct thread_info *tp;
+ int any_process_wildcard;
+ int may_global_wildcard_vcont;
+ struct vcont_builder vcont_builder;
+
+ /* If connected in all-stop mode, we'd send the remote resume
+ request directly from remote_resume. Likewise if
+ reverse-debugging, as there are no defined vCont actions for
+ reverse execution. */
+ if (!target_is_non_stop_p () || execution_direction == EXEC_REVERSE)
+ return;
+
+ /* Try to send wildcard actions ("vCont;c" or "vCont;c:pPID.-1")
+ instead of resuming all threads of each process individually.
+ However, if any thread of a process must remain halted, we can't
+ send wildcard resumes and must send one action per thread.
+
+ Care must be taken to not resume threads/processes the server
+ side already told us are stopped, but the core doesn't know about
+ yet, because the events are still in the vStopped notification
+ queue. For example:
+
+ #1 => vCont s:p1.1;c
+ #2 <= OK
+ #3 <= %Stopped T05 p1.1
+ #4 => vStopped
+ #5 <= T05 p1.2
+ #6 => vStopped
+ #7 <= OK
+ #8 (infrun handles the stop for p1.1 and continues stepping)
+ #9 => vCont s:p1.1;c
+
+ The last vCont above would resume thread p1.2 by mistake, because
+ the server has no idea that the event for p1.2 had not been
+ handled yet.
+
+ The server side must similarly ignore resume actions for the
+ thread that has a pending %Stopped notification (and any other
+ threads with events pending), until GDB acks the notification
+ with vStopped. Otherwise, e.g., the following case is
+ mishandled:
+
+ #1 => g (or any other packet)
+ #2 <= [registers]
+ #3 <= %Stopped T05 p1.2
+ #4 => vCont s:p1.1;c
+ #5 <= OK
+
+ Above, the server must not resume thread p1.2. GDB can't know
+ that p1.2 stopped until it acks the %Stopped notification, and
+ since from GDB's perspective all threads should be running, it
+ sends a "c" action.
+
+ Finally, special care must also be given to handling fork/vfork
+ events. A (v)fork event actually tells us that two processes
+ stopped -- the parent and the child. Until we follow the fork,
+ we must not resume the child. Therefore, if we have a pending
+ fork follow, we must not send a global wildcard resume action
+ (vCont;c). We can still send process-wide wildcards though. */
+
+ /* Start by assuming a global wildcard (vCont;c) is possible. */
+ may_global_wildcard_vcont = 1;
+
+ /* And assume every process is individually wildcard-able too. */
+ ALL_NON_EXITED_INFERIORS (inf)
+ {
+ if (inf->priv == NULL)
+ inf->priv = XNEW (struct private_inferior);
+ inf->priv->may_wildcard_vcont = 1;
+ }
+
+ /* Check for any pending events (not reported or processed yet) and
+ disable process and global wildcard resumes appropriately. */
+ check_pending_events_prevent_wildcard_vcont (&may_global_wildcard_vcont);
+
+ ALL_NON_EXITED_THREADS (tp)
+ {
+ /* If a thread of a process is not meant to be resumed, then we
+ can't wildcard that process. */
+ if (!tp->executing)
+ {
+ tp->inf->priv->may_wildcard_vcont = 0;
+
+ /* And if we can't wildcard a process, we can't wildcard
+ everything either. */
+ may_global_wildcard_vcont = 0;
+ continue;
+ }
+
+ /* If a thread is the parent of an unfollowed fork, then we
+ can't do a global wildcard, as that would resume the fork
+ child. */
+ if (is_pending_fork_parent_thread (tp))
+ may_global_wildcard_vcont = 0;
+ }
+
+ /* Now let's build the vCont packet(s). Actions must be appended
+ from narrower to wider scopes (thread -> process -> global). If
+ we end up with too many actions for a single packet vcont_builder
+ flushes the current vCont packet to the remote side and starts a
+ new one. */
+ vcont_builder_restart (&vcont_builder);
+
+ /* Threads first. */
+ ALL_NON_EXITED_THREADS (tp)
+ {
+ struct private_thread_info *remote_thr = tp->priv;
+
+ if (!tp->executing || remote_thr->vcont_resumed)
+ continue;
+
+ gdb_assert (!thread_is_in_step_over_chain (tp));
+
+ if (!remote_thr->last_resume_step
+ && remote_thr->last_resume_sig == GDB_SIGNAL_0
+ && tp->inf->priv->may_wildcard_vcont)
+ {
+ /* We'll send a wildcard resume instead. */
+ remote_thr->vcont_resumed = 1;
+ continue;
+ }
+
+ vcont_builder_push_action (&vcont_builder, tp->ptid,
+ remote_thr->last_resume_step,
+ remote_thr->last_resume_sig);
+ remote_thr->vcont_resumed = 1;
+ }
+
+ /* Now check whether we can send any process-wide wildcard. This is
+ to avoid sending a global wildcard in the case nothing is
+ supposed to be resumed. */
+ any_process_wildcard = 0;
+
+ ALL_NON_EXITED_INFERIORS (inf)
+ {
+ if (inf->priv->may_wildcard_vcont)
+ {
+ any_process_wildcard = 1;
+ break;
+ }
+ }
+
+ if (any_process_wildcard)
+ {
+ /* If all processes are wildcard-able, then send a single "c"
+ action, otherwise, send an "all (-1) threads of process"
+ continue action for each running process, if any. */
+ if (may_global_wildcard_vcont)
+ {
+ vcont_builder_push_action (&vcont_builder, minus_one_ptid,
+ 0, GDB_SIGNAL_0);
+ }
+ else
+ {
+ ALL_NON_EXITED_INFERIORS (inf)
+ {
+ if (inf->priv->may_wildcard_vcont)
+ {
+ vcont_builder_push_action (&vcont_builder,
+ pid_to_ptid (inf->pid),
+ 0, GDB_SIGNAL_0);
+ }
+ }
+ }
+ }
+
+ vcont_builder_flush (&vcont_builder);
+}
+
\f
/* Non-stop version of target_stop. Uses `vCont;t' to stop a remote
struct stop_reply *output;
};
-/* Determine if THREAD is a pending fork parent thread. ARG contains
+/* Determine if THREAD_PTID is a pending fork parent thread. ARG contains
the pid of the process that owns the threads we want to check, or
-1 if we want to check all threads. */
return 0;
}
+/* Return the thread's pending status used to determine whether the
+ thread is a fork parent stopped at a fork event. */
+
+static struct target_waitstatus *
+thread_pending_fork_status (struct thread_info *thread)
+{
+ if (thread->suspend.waitstatus_pending_p)
+ return &thread->suspend.waitstatus;
+ else
+ return &thread->pending_follow;
+}
+
+/* Determine if THREAD is a pending fork parent thread. */
+
+static int
+is_pending_fork_parent_thread (struct thread_info *thread)
+{
+ struct target_waitstatus *ws = thread_pending_fork_status (thread);
+ int pid = -1;
+
+ return is_pending_fork_parent (ws, pid, thread->ptid);
+}
+
/* Check whether EVENT is a fork event, and if it is, remove the
fork child from the context list passed in DATA. */
fork child threads from the CONTEXT list. */
ALL_NON_EXITED_THREADS (thread)
{
- struct target_waitstatus *ws;
-
- if (thread->suspend.waitstatus_pending_p)
- ws = &thread->suspend.waitstatus;
- else
- ws = &thread->pending_follow;
+ struct target_waitstatus *ws = thread_pending_fork_status (thread);
if (is_pending_fork_parent (ws, pid, thread->ptid))
{
remove_child_of_pending_fork, ¶m);
}
+/* Check whether EVENT would prevent a global or process wildcard
+ vCont action. */
+
+static int
+check_pending_event_prevents_wildcard_vcont_callback
+ (QUEUE (stop_reply_p) *q,
+ QUEUE_ITER (stop_reply_p) *iter,
+ stop_reply_p event,
+ void *data)
+{
+ struct inferior *inf;
+ int *may_global_wildcard_vcont = (int *) data;
+
+ if (event->ws.kind == TARGET_WAITKIND_NO_RESUMED
+ || event->ws.kind == TARGET_WAITKIND_NO_HISTORY)
+ return 1;
+
+ if (event->ws.kind == TARGET_WAITKIND_FORKED
+ || event->ws.kind == TARGET_WAITKIND_VFORKED)
+ *may_global_wildcard_vcont = 0;
+
+ inf = find_inferior_ptid (event->ptid);
+
+ /* This may be the first time we heard about this process.
+ Regardless, we must not do a global wildcard resume, otherwise
+ we'd resume this process too. */
+ *may_global_wildcard_vcont = 0;
+ if (inf != NULL)
+ inf->priv->may_wildcard_vcont = 0;
+
+ return 1;
+}
+
+/* Check whether any event pending in the vStopped queue would prevent
+ a global or process wildcard vCont action. Clear
+ *may_global_wildcard if we can't do a global wildcard (vCont;c),
+ and clear the event inferior's may_wildcard_vcont flag if we can't
+ do a process-wide wildcard resume (vCont;c:pPID.-1). */
+
+static void
+check_pending_events_prevent_wildcard_vcont (int *may_global_wildcard)
+{
+ struct notif_client *notif = ¬if_client_stop;
+
+ remote_notif_get_pending_events (notif);
+ QUEUE_iterate (stop_reply_p, stop_reply_queue,
+ check_pending_event_prevents_wildcard_vcont_callback,
+ may_global_wildcard);
+}
+
/* Remove stop replies in the queue if its pid is equal to the given
inferior's pid. */
}
remote_notice_new_inferior (ptid, 0);
- remote_thr = demand_private_info (ptid);
+ remote_thr = get_private_info_ptid (ptid);
remote_thr->core = stop_reply->core;
remote_thr->stop_reason = stop_reply->stop_reason;
remote_thr->watch_data_address = stop_reply->watch_data_address;
+ remote_thr->vcont_resumed = 0;
}
stop_reply_xfree (stop_reply);
remote_ops.to_detach = remote_detach;
remote_ops.to_disconnect = remote_disconnect;
remote_ops.to_resume = remote_resume;
+ remote_ops.to_commit_resume = remote_commit_resume;
remote_ops.to_wait = remote_wait;
remote_ops.to_fetch_registers = remote_fetch_registers;
remote_ops.to_store_registers = remote_store_registers;
projects / binutils-gdb.git / commitdiff