gdb/

2012-06-06  Pedro Alves  <palves@redhat.com>

	* infrun.c (struct execution_control_state): Remove
	`new_thread_event' field.
	(handle_inferior_event): Simplify new threads handling; don't
	resume the inferior if we find a new thread.

gdb/testsuite/
2012-06-06  Pedro Alves  <palves@redhat.com>

	* gdb.threads/clone-new-thread-event.c: New file.
	* gdb.threads/clone-new-thread-event.exp: New file.

gdb/ChangeLog

@@ -1,3 +1,10 @@
+2012-06-06  Pedro Alves  <palves@redhat.com>
+
+	* infrun.c (struct execution_control_state): Remove
+	`new_thread_event' field.
+	(handle_inferior_event): Simplify new threads handling; don't
+	resume the inferior if we find a new thread.
+
 2012-06-06  Thomas Schwinge  <thomas@codesourcery.com>
 
 	* NEWS: Document the deprecation of SH's 'regs' command.

gdb/infrun.c

@@ -2393,7 +2393,6 @@ struct execution_control_state
   CORE_ADDR stop_func_start;
   CORE_ADDR stop_func_end;
   const char *stop_func_name;
-  int new_thread_event;
   int wait_some_more;
 };
 
@@ -3229,17 +3228,15 @@ handle_inferior_event (struct execution_control_state *ecs)
       return;
     }
 
-  /* If it's a new process, add it to the thread database.  */
-
-  ecs->new_thread_event = (!ptid_equal (ecs->ptid, inferior_ptid)
-			   && !ptid_equal (ecs->ptid, minus_one_ptid)
-			   && !in_thread_list (ecs->ptid));
-
   if (ecs->ws.kind != TARGET_WAITKIND_EXITED
-      && ecs->ws.kind != TARGET_WAITKIND_SIGNALLED && ecs->new_thread_event)
-    add_thread (ecs->ptid);
-
-  ecs->event_thread = find_thread_ptid (ecs->ptid);
+      && ecs->ws.kind != TARGET_WAITKIND_SIGNALLED
+      && !ptid_equal (ecs->ptid, minus_one_ptid))
+    {
+      ecs->event_thread = find_thread_ptid (ecs->ptid);
+      /* If it's a new thread, add it to the thread database.  */
+      if (ecs->event_thread == NULL)
+	ecs->event_thread = add_thread (ecs->ptid);
+    }
 
   /* Dependent on valid ECS->EVENT_THREAD.  */
   adjust_pc_after_break (ecs);
@@ -3713,30 +3710,6 @@ handle_inferior_event (struct execution_control_state *ecs)
       return;
     }
 
-  if (ecs->new_thread_event)
-    {
-      if (non_stop)
-	/* Non-stop assumes that the target handles adding new threads
-	   to the thread list.  */
-	internal_error (__FILE__, __LINE__,
-			"targets should add new threads to the thread "
-			"list themselves in non-stop mode.");
-
-      /* We may want to consider not doing a resume here in order to
-	 give the user a chance to play with the new thread.  It might
-	 be good to make that a user-settable option.  */
-
-      /* At this point, all threads are stopped (happens automatically
-	 in either the OS or the native code).  Therefore we need to
-	 continue all threads in order to make progress.  */
-
-      if (!ptid_equal (ecs->ptid, inferior_ptid))
-	context_switch (ecs->ptid);
-      target_resume (RESUME_ALL, 0, GDB_SIGNAL_0);
-      prepare_to_wait (ecs);
-      return;
-    }
-
   if (ecs->ws.kind == TARGET_WAITKIND_STOPPED)
     {
       /* Do we need to clean up the state of a thread that has

gdb/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2012-06-06  Pedro Alves  <palves@redhat.com>
+
+	* gdb.threads/clone-new-thread-event.c: New file.
+	* gdb.threads/clone-new-thread-event.exp: New file.
+
 2012-06-06  Yao Qi  <yao@codesourcery.com>
 
 	* gdb.base/dprintf.c (main): Add extra parameter when calling

gdb/testsuite/gdb.threads/clone-new-thread-event.c

@@ -0,0 +1,75 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2009-2012 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+   Test that GDB doesn't lose an event for a thread it didn't know
+   about, until an event is reported for it.  */
+
+#define _GNU_SOURCE
+#include <sched.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+
+#include <features.h>
+#ifdef __UCLIBC__
+#if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__))
+#define HAS_NOMMU
+#endif
+#endif
+
+#define STACK_SIZE 0x1000
+
+static int
+tkill (int lwpid, int signo)
+{
+  return syscall (__NR_tkill, lwpid, signo);
+}
+
+static pid_t
+gettid (void)
+{
+  return syscall (__NR_gettid);
+}
+
+static int
+fn (void *unused)
+{
+  tkill (gettid (), SIGUSR1);
+  return 0;
+}
+
+int
+main (int argc, char **argv)
+{
+  unsigned char *stack;
+  int new_pid;
+
+  stack = malloc (STACK_SIZE);
+  assert (stack != NULL);
+
+  new_pid = clone (fn, stack + STACK_SIZE, CLONE_FILES
+#if defined(__UCLIBC__) && defined(HAS_NOMMU)
+		   | CLONE_VM
+#endif /* defined(__UCLIBC__) && defined(HAS_NOMMU) */
+		   , NULL, NULL, NULL, NULL);
+  assert (new_pid > 0);
+
+  return 0;
+}

gdb/testsuite/gdb.threads/clone-new-thread-event.exp

@@ -0,0 +1,34 @@
+# This testcase is part of GDB, the GNU debugger.
+
+# Copyright 2012 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This only works on targets with the Linux kernel.
+if ![istarget *-*-linux*] then {
+    return
+}
+
+if { [prepare_for_testing clone-new-thread-event.exp clone-new-thread-event] } {
+    return -1
+}
+
+if { ![runto_main] } {
+    untested "could not run to main"
+    return -1
+}
+
+gdb_test "continue" \
+    "Program received signal SIGUSR1, User defined signal 1.*" \
+    "catch SIGUSR1"