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[PATCH] Don't switch to the event thread early in non-stop mode.
- From: Pedro Alves <palves at redhat dot com>
- To: gdb-patches at sourceware dot org
- Date: Tue, 12 Jun 2012 19:44:40 +0100
- Subject: [PATCH] Don't switch to the event thread early in non-stop mode.
It is largely no longer necessary to special case non-stop mode, WRT
caring about the current context being set (the real "context
switching" context_switch used to exist for, is gone) before calling
handle_inferior event. Trying to harmonize all-stop and non-stop
modes a bit further, this removes that non-stop special casing. I
went through handle_inferior_event looking for places that miss
switching to the event thread and made them do so. The missing
switching was never missed for single-process all-stop, but it's
important for both multi-process all-stop, and non-stop, so we don't
e.g., remove breakpoints in the context of a previously selected
inferior or thread that has already exited, or is presently running.
I actually was going to push a patch that centralized all the
context_switch calls at the top of handle_inferior_event (and I've
mentioned wanted to do it before a few times in the past years), but
in the end decided against, mostly because it felt counter to all the
parameterization in handle_inferior_event that moves away from global
state.
Tested on x86_64 Fedora 16, native and gdbserver, and applied.
2012-06-12 Pedro Alves <palves@redhat.com>
* infrun.c (infrun_thread_stop_requested_callback): Don't switch
threads here.
(prepare_for_detach): No longer context switch here in non-stop
mode.
(fetch_inferior_event): Ditto.
(handle_inferior_event) <STOP_QUIETLY || NO_STOP_QUIETLY>: Switch
to the event thread before removing breakpoints. Switch to the
event thread before inserting breakpoints and resuming.
(handle_inferior_event) <TARGET_WAITKIND_SPURIOUS>: Switch to the
event thread before resuming.
(handle_inferior_event) <stepping_past_singlestep_breakpoint>:
Switch to the event thread before removing breakpoints.
---
gdb/infrun.c | 30 ++++++++++--------------------
1 files changed, 10 insertions(+), 20 deletions(-)
diff --git a/gdb/infrun.c b/gdb/infrun.c
index b98e379..e36e42e 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -2437,8 +2437,6 @@ infrun_thread_stop_requested_callback (struct thread_info *info, void *arg)
old_chain = make_cleanup_restore_current_thread ();
- switch_to_thread (info->ptid);
-
/* Go through handle_inferior_event/normal_stop, so we always
have consistent output as if the stop event had been
reported. */
@@ -2655,14 +2653,6 @@ prepare_for_detach (void)
old_chain_2 = make_cleanup (finish_thread_state_cleanup,
&minus_one_ptid);
- /* In non-stop mode, each thread is handled individually.
- Switch early, so the global state is set correctly for this
- thread. */
- if (non_stop
- && ecs->ws.kind != TARGET_WAITKIND_EXITED
- && ecs->ws.kind != TARGET_WAITKIND_SIGNALLED)
- context_switch (ecs->ptid);
-
/* Now figure out what to do with the result of the result. */
handle_inferior_event (ecs);
@@ -2789,16 +2779,6 @@ fetch_inferior_event (void *client_data)
if (debug_infrun)
print_target_wait_results (waiton_ptid, ecs->ptid, &ecs->ws);
- if (non_stop
- && ecs->ws.kind != TARGET_WAITKIND_IGNORE
- && ecs->ws.kind != TARGET_WAITKIND_NO_RESUMED
- && ecs->ws.kind != TARGET_WAITKIND_EXITED
- && ecs->ws.kind != TARGET_WAITKIND_SIGNALLED)
- /* In non-stop mode, each thread is handled individually. Switch
- early, so the global state is set correctly for this
- thread. */
- context_switch (ecs->ptid);
-
/* If an error happens while handling the event, propagate GDB's
knowledge of the executing state to the frontend/user running
state. */
@@ -3380,6 +3360,9 @@ handle_inferior_event (struct execution_control_state *ecs)
we're attaching or setting up a remote connection. */
if (stop_soon == STOP_QUIETLY || stop_soon == NO_STOP_QUIETLY)
{
+ if (!ptid_equal (ecs->ptid, inferior_ptid))
+ context_switch (ecs->ptid);
+
/* Loading of shared libraries might have changed breakpoint
addresses. Make sure new breakpoints are inserted. */
if (stop_soon == NO_STOP_QUIETLY
@@ -3395,6 +3378,9 @@ handle_inferior_event (struct execution_control_state *ecs)
case TARGET_WAITKIND_SPURIOUS:
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_SPURIOUS\n");
+ if (!ptid_equal (ecs->ptid, inferior_ptid)
+ && !ptid_equal (ecs->ptid, minus_one_ptid))
+ context_switch (ecs->ptid);
resume (0, GDB_SIGNAL_0);
prepare_to_wait (ecs);
return;
@@ -3769,6 +3755,8 @@ handle_inferior_event (struct execution_control_state *ecs)
"infrun: stepping_past_"
"singlestep_breakpoint\n");
/* Pull the single step breakpoints out of the target. */
+ if (!ptid_equal (ecs->ptid, inferior_ptid))
+ context_switch (ecs->ptid);
remove_single_step_breakpoints ();
singlestep_breakpoints_inserted_p = 0;
@@ -3801,6 +3789,8 @@ handle_inferior_event (struct execution_control_state *ecs)
/* Pull the single step breakpoints out of the target. */
if (singlestep_breakpoints_inserted_p)
{
+ if (!ptid_equal (ecs->ptid, inferior_ptid))
+ context_switch (ecs->ptid);
remove_single_step_breakpoints ();
singlestep_breakpoints_inserted_p = 0;
}