diff options
Diffstat (limited to 'gdb/remote.c')
| -rw-r--r-- | gdb/remote.c | 453 |
1 files changed, 430 insertions, 23 deletions
diff --git a/gdb/remote.c b/gdb/remote.c index 60e2dda5f17..453ce0f6617 100644 --- a/gdb/remote.c +++ b/gdb/remote.c @@ -441,6 +441,24 @@ struct private_thread_info /* 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_do_resume. remote_resume stores each + thread's last resume request in these fields, so that a later + remote_do_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 @@ -1797,6 +1815,9 @@ remote_add_inferior (int fake_pid_p, int pid, int attached, 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. */ @@ -1804,6 +1825,7 @@ static void remote_add_thread (ptid_t ptid, int running) { 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 @@ -1812,10 +1834,11 @@ remote_add_thread (ptid_t ptid, int running) 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 = running; set_executing (ptid, running); set_running (ptid, running); } @@ -1904,25 +1927,40 @@ remote_notice_new_inferior (ptid_t currthread, int 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 (info); + gdb_assert (thread != NULL); - 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 @@ -3266,7 +3304,7 @@ remote_update_thread_list (struct target_ops *ops) remote_notice_new_inferior (item->ptid, running); - info = demand_private_info (item->ptid); + info = get_private_info_ptid (item->ptid); info->core = item->core; info->extra = item->extra; item->extra = NULL; @@ -3900,6 +3938,7 @@ process_initial_stop_replies (int from_tty) set_executing (event_ptid, 0); set_running (event_ptid, 0); + thread->priv->vcont_resumed = 0; } /* "Notice" the new inferiors before anything related to @@ -5605,6 +5644,26 @@ remote_resume (struct target_ops *ops, { 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_do_resume / remote_do_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 @@ -5638,6 +5697,284 @@ remote_resume (struct target_ops *ops, 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 resumptions than would fit a single + packet. */ + +struct vcont_builder +{ + /* Pointer to the first action. P points here if no resumption has + been appended yet. */ + char *first_action; + + /* Where the next resumption 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 resumption is range-stepping, with its two addresses. + This is more than sufficient. If a new, bigger resumption 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_do_resume implementation. */ + +static void +remote_do_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); +} + /* Set up the signal handler for SIGINT, while the target is @@ -6120,7 +6457,7 @@ struct queue_iter_param 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. */ @@ -6138,6 +6475,29 @@ is_pending_fork_parent (struct target_waitstatus *ws, int event_pid, 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. */ @@ -6177,12 +6537,7 @@ remove_new_fork_children (struct threads_listing_context *context) 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)) { @@ -6200,6 +6555,56 @@ remove_new_fork_children (struct threads_listing_context *context) 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 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. */ @@ -6830,10 +7235,11 @@ process_stop_reply (struct stop_reply *stop_reply, } 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); @@ -13044,6 +13450,7 @@ Specify the serial device it is connected to\n\ remote_ops.to_detach = remote_detach; remote_ops.to_disconnect = remote_disconnect; remote_ops.to_resume = remote_resume; + remote_ops.to_do_resume = remote_do_resume; remote_ops.to_wait = remote_wait; remote_ops.to_fetch_registers = remote_fetch_registers; remote_ops.to_store_registers = remote_store_registers; |