From 47608cb1acc3880b330b8d3a8ad6aa29218046d9 Mon Sep 17 00:00:00 2001
From: Pedro Alves <palves@redhat.com>
Date: Thu, 21 May 2009 15:48:42 +0000
Subject: [PATCH] 	* target.h (TARGET_WNOHANG): New. 	* target.c
 (target_wait): Add `options' argument.  Adjust. 	(struct target_ops)
 <to_wait>: Add `options' argument. 	(target_wait): Add `options' argument.
 	* infrun.c (wait_for_inferior): Pass 0 as options to 	target_wait
 (blocking wait). 	(fetch_inferior_event): Pass TARGET_WNOHANG as options
 to 	target_wait. 	* fork-child.c (startup_inferior): Pass 0 as options
 to 	target_wait (blocking wait). 	* linux-nat.c
 (linux_nat_create_inferior): Remove async masking. 	(linux_nat_wait_1):
 Add `target_options' argument.  Use it instead 	of checking on
 target_can_async_p. 	(linux_nat_wait): Add `target_options' argument. 
 Adjust. 	* remote.c (remote_wait_ns): Add `options' argument.  Adjust
 to 	check on TARGET_WNOWAIT instead of checking on remote_is_async_p. 
 (remote_wait_as): Add `options' argument.  Adjust to check on 	TARGET_WNOWAIT
 instead of checking on remote_is_async_p.  If doing 	a blocking wait, keep
 waiting until an interesting event comes 	out. 	(remote_wait): Add
 `options' argument.  Don't loop here if the 	target is in async mode, and a
 blocking wait has been requested.

	* top.c (deprecated_target_wait_hook): Add `options' argument.
	* linux-thread-db.c (thread_db_wait): Add `options' argument, and
	pass it down to the layer beneath.
	* inf-ptrace.c (inf_ptrace_wait): Add `options' argument.
	* record.c (record_beneath_to_wait): Add `options' argument.
	(record_wait): Add `options' argument, and pass it down to the
	layer beneath.
	* bsd-uthread.c (bsd_uthread_wait): Add `options' argument.
	* darwin-nat.c (darwin_wait): Likewise.
	* defs.h (deprecated_target_wait_hook): Likewise.
	* gnu-nat.c (gnu_wait): Add `options' argument.
	* go32-nat.c (go32_wait): Likewise.
	* hpux-thread.c (hpux_thread_wait): Add `options' argument, and
	pass it down to the layer beneath.
	* inf-ttrace.c (inf_ttrace_wait): Add `options' argument.
	* monitor.c (monitor_wait): Likewise.
	* nto-procfs.c (procfs_wait): Likewise.
	* remote-mips.c (mips_wait): Add `options' argument.
	* remote-sim.c (gdbsim_wait): Likewise.
	* rs6000-nat.c (rs6000_wait): Add `options' argument.
	* sol-thread.c (sol_thread_wait): Add `options' argument, and pass
	it down to the layer beneath.
	* spu-linux-nat.c (spu_child_wait): Add `options' argument.
	* windows-nat.c (windows_wait): Likewise.
	* tui/tui-hooks.c (tui_target_wait_hook): Likewise.  Adjust.
---
 gdb/ChangeLog         | 51 +++++++++++++++++++++++++++++++++++++++++++
 gdb/bsd-uthread.c     |  4 ++--
 gdb/darwin-nat.c      |  2 +-
 gdb/defs.h            |  3 ++-
 gdb/fork-child.c      |  2 +-
 gdb/gnu-nat.c         |  2 +-
 gdb/go32-nat.c        |  2 +-
 gdb/hpux-thread.c     |  4 ++--
 gdb/inf-ptrace.c      |  2 +-
 gdb/inf-ttrace.c      |  2 +-
 gdb/infrun.c          |  8 +++----
 gdb/linux-nat.c       | 24 ++++++++------------
 gdb/linux-thread-db.c |  5 +++--
 gdb/monitor.c         |  2 +-
 gdb/nto-procfs.c      |  2 +-
 gdb/record.c          | 10 +++++----
 gdb/remote-mips.c     |  2 +-
 gdb/remote-sim.c      |  2 +-
 gdb/remote.c          | 39 +++++++++++++++------------------
 gdb/rs6000-nat.c      |  2 +-
 gdb/sol-thread.c      |  4 ++--
 gdb/spu-linux-nat.c   |  2 +-
 gdb/target.c          |  4 ++--
 gdb/target.h          | 15 ++++++++++---
 gdb/top.c             |  3 ++-
 gdb/tui/tui-hooks.c   |  4 ++--
 gdb/windows-nat.c     |  2 +-
 27 files changed, 130 insertions(+), 74 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 70e30dd6db..c45f8aaebb 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,54 @@
+2009-05-21  Pedro Alves  <pedro@codesourcery.com>
+
+	* target.h (TARGET_WNOHANG): New.
+	* target.c (target_wait): Add `options' argument.  Adjust.
+	(struct target_ops) <to_wait>: Add `options' argument.
+	(target_wait): Add `options' argument.
+	* infrun.c (wait_for_inferior): Pass 0 as options to
+	target_wait (blocking wait).
+	(fetch_inferior_event): Pass TARGET_WNOHANG as options to
+	target_wait.
+	* fork-child.c (startup_inferior): Pass 0 as options to
+	target_wait (blocking wait).
+	* linux-nat.c (linux_nat_create_inferior): Remove async masking.
+	(linux_nat_wait_1): Add `target_options' argument.  Use it instead
+	of checking on target_can_async_p.
+	(linux_nat_wait): Add `target_options' argument.  Adjust.
+	* remote.c (remote_wait_ns): Add `options' argument.  Adjust to
+	check on TARGET_WNOWAIT instead of checking on remote_is_async_p.
+	(remote_wait_as): Add `options' argument.  Adjust to check on
+	TARGET_WNOWAIT instead of checking on remote_is_async_p.  If doing
+	a blocking wait, keep waiting until an interesting event comes
+	out.
+	(remote_wait): Add `options' argument.  Don't loop here if the
+	target is in async mode, and a blocking wait has been requested.
+
+	* top.c (deprecated_target_wait_hook): Add `options' argument.
+	* linux-thread-db.c (thread_db_wait): Add `options' argument, and
+	pass it down to the layer beneath.
+	* inf-ptrace.c (inf_ptrace_wait): Add `options' argument.
+	* record.c (record_beneath_to_wait): Add `options' argument.
+	(record_wait): Add `options' argument, and pass it down to the
+	layer beneath.
+	* bsd-uthread.c (bsd_uthread_wait): Add `options' argument.
+	* darwin-nat.c (darwin_wait): Likewise.
+	* defs.h (deprecated_target_wait_hook): Likewise.
+	* gnu-nat.c (gnu_wait): Add `options' argument.
+	* go32-nat.c (go32_wait): Likewise.
+	* hpux-thread.c (hpux_thread_wait): Add `options' argument, and
+	pass it down to the layer beneath.
+	* inf-ttrace.c (inf_ttrace_wait): Add `options' argument.
+	* monitor.c (monitor_wait): Likewise.
+	* nto-procfs.c (procfs_wait): Likewise.
+	* remote-mips.c (mips_wait): Add `options' argument.
+	* remote-sim.c (gdbsim_wait): Likewise.
+	* rs6000-nat.c (rs6000_wait): Add `options' argument.
+	* sol-thread.c (sol_thread_wait): Add `options' argument, and pass
+	it down to the layer beneath.
+	* spu-linux-nat.c (spu_child_wait): Add `options' argument.
+	* windows-nat.c (windows_wait): Likewise.
+	* tui/tui-hooks.c (tui_target_wait_hook): Likewise.  Adjust.
+
 2009-05-21  Pedro Alves  <pedro@codesourcery.com>
 
 	* mi/mi-interp.c (mi_on_resume): Account for whole process
diff --git a/gdb/bsd-uthread.c b/gdb/bsd-uthread.c
index 5b0aa51a63..18287af9e8 100644
--- a/gdb/bsd-uthread.c
+++ b/gdb/bsd-uthread.c
@@ -345,13 +345,13 @@ bsd_uthread_xfer_partial (struct target_ops *ops, enum target_object object,
 
 static ptid_t
 bsd_uthread_wait (struct target_ops *ops,
-		  ptid_t ptid, struct target_waitstatus *status)
+		  ptid_t ptid, struct target_waitstatus *status, int options)
 {
   CORE_ADDR addr;
   struct target_ops *beneath = find_target_beneath (ops);
 
   /* Pass the request to the layer beneath.  */
-  ptid = beneath->to_wait (beneath, ptid, status);
+  ptid = beneath->to_wait (beneath, ptid, status, options);
 
   /* If the process is no longer alive, there's no point in figuring
      out the thread ID.  It will fail anyway.  */
diff --git a/gdb/darwin-nat.c b/gdb/darwin-nat.c
index dc51ec635c..8c20bd905a 100644
--- a/gdb/darwin-nat.c
+++ b/gdb/darwin-nat.c
@@ -476,7 +476,7 @@ catch_exception_raise (mach_port_t port,
 
 static ptid_t
 darwin_wait (struct target_ops *ops,
-	     ptid_t ptid, struct target_waitstatus *status)
+	     ptid_t ptid, struct target_waitstatus *status, int options)
 {
   kern_return_t kret;
   mach_msg_header_t *hdr = &msgin.hdr;
diff --git a/gdb/defs.h b/gdb/defs.h
index abf4b0285e..0f91f3f1b9 100644
--- a/gdb/defs.h
+++ b/gdb/defs.h
@@ -1111,7 +1111,8 @@ extern void (*deprecated_register_changed_hook) (int regno);
 extern void (*deprecated_memory_changed_hook) (CORE_ADDR addr, int len);
 extern void (*deprecated_context_hook) (int);
 extern ptid_t (*deprecated_target_wait_hook) (ptid_t ptid,
-                                         struct target_waitstatus * status);
+					      struct target_waitstatus *status,
+					      int options);
 
 extern void (*deprecated_attach_hook) (void);
 extern void (*deprecated_detach_hook) (void);
diff --git a/gdb/fork-child.c b/gdb/fork-child.c
index 988154a11b..9eadbc9969 100644
--- a/gdb/fork-child.c
+++ b/gdb/fork-child.c
@@ -448,7 +448,7 @@ startup_inferior (int ntraps)
 
       struct target_waitstatus ws;
       memset (&ws, 0, sizeof (ws));
-      event_ptid = target_wait (resume_ptid, &ws);
+      event_ptid = target_wait (resume_ptid, &ws, 0);
 
       if (ws.kind == TARGET_WAITKIND_IGNORE)
 	/* The inferior didn't really stop, keep waiting.  */
diff --git a/gdb/gnu-nat.c b/gdb/gnu-nat.c
index b3b89a40a6..daafb6250b 100644
--- a/gdb/gnu-nat.c
+++ b/gdb/gnu-nat.c
@@ -1435,7 +1435,7 @@ struct inf *waiting_inf;
 /* Wait for something to happen in the inferior, returning what in STATUS. */
 static ptid_t
 gnu_wait (struct target_ops *ops,
-	  ptid_t ptid, struct target_waitstatus *status)
+	  ptid_t ptid, struct target_waitstatus *status, int options)
 {
   struct msg
     {
diff --git a/gdb/go32-nat.c b/gdb/go32-nat.c
index 5af281959b..f0a3236c18 100644
--- a/gdb/go32-nat.c
+++ b/gdb/go32-nat.c
@@ -416,7 +416,7 @@ static char child_cwd[FILENAME_MAX];
 
 static ptid_t
 go32_wait (struct target_ops *ops,
-	   ptid_t ptid, struct target_waitstatus *status)
+	   ptid_t ptid, struct target_waitstatus *status, int options)
 {
   int i;
   unsigned char saved_opcode;
diff --git a/gdb/hpux-thread.c b/gdb/hpux-thread.c
index bdc547d97b..ac96a7fe6c 100644
--- a/gdb/hpux-thread.c
+++ b/gdb/hpux-thread.c
@@ -190,7 +190,7 @@ hpux_thread_resume (struct target_ops *ops,
 
 static ptid_t
 hpux_thread_wait (struct target_ops *ops,
-		  ptid_t ptid, struct target_waitstatus *ourstatus)
+		  ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 {
   ptid_t rtnval;
   struct cleanup *old_chain;
@@ -203,7 +203,7 @@ hpux_thread_wait (struct target_ops *ops,
     ptid = main_ptid;
 
   rtnval = deprecated_child_ops.to_wait (&deprecated_child_ops,
-					 ptid, ourstatus);
+					 ptid, ourstatus, options);
 
   rtnval = find_active_thread ();
 
diff --git a/gdb/inf-ptrace.c b/gdb/inf-ptrace.c
index d9f7338616..7076da7073 100644
--- a/gdb/inf-ptrace.c
+++ b/gdb/inf-ptrace.c
@@ -396,7 +396,7 @@ inf_ptrace_resume (struct target_ops *ops,
 
 static ptid_t
 inf_ptrace_wait (struct target_ops *ops,
-		 ptid_t ptid, struct target_waitstatus *ourstatus)
+		 ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 {
   pid_t pid;
   int status, save_errno;
diff --git a/gdb/inf-ttrace.c b/gdb/inf-ttrace.c
index e78ad8ecf2..a4c4b99aa6 100644
--- a/gdb/inf-ttrace.c
+++ b/gdb/inf-ttrace.c
@@ -924,7 +924,7 @@ inf_ttrace_resume (struct target_ops *ops,
 
 static ptid_t
 inf_ttrace_wait (struct target_ops *ops,
-		 ptid_t ptid, struct target_waitstatus *ourstatus)
+		 ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 {
   pid_t pid = ptid_get_pid (ptid);
   lwpid_t lwpid = ptid_get_lwp (ptid);
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 99873b180a..489f9d160e 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -1842,9 +1842,9 @@ wait_for_inferior (int treat_exec_as_sigtrap)
       struct cleanup *old_chain;
 
       if (deprecated_target_wait_hook)
-	ecs->ptid = deprecated_target_wait_hook (waiton_ptid, &ecs->ws);
+	ecs->ptid = deprecated_target_wait_hook (waiton_ptid, &ecs->ws, 0);
       else
-	ecs->ptid = target_wait (waiton_ptid, &ecs->ws);
+	ecs->ptid = target_wait (waiton_ptid, &ecs->ws, 0);
 
       if (debug_infrun)
 	print_target_wait_results (waiton_ptid, ecs->ptid, &ecs->ws);
@@ -1920,9 +1920,9 @@ fetch_inferior_event (void *client_data)
 
   if (deprecated_target_wait_hook)
     ecs->ptid =
-      deprecated_target_wait_hook (waiton_ptid, &ecs->ws);
+      deprecated_target_wait_hook (waiton_ptid, &ecs->ws, TARGET_WNOHANG);
   else
-    ecs->ptid = target_wait (waiton_ptid, &ecs->ws);
+    ecs->ptid = target_wait (waiton_ptid, &ecs->ws, TARGET_WNOHANG);
 
   if (debug_infrun)
     print_target_wait_results (waiton_ptid, ecs->ptid, &ecs->ws);
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index d579920000..8f12587950 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -1341,7 +1341,6 @@ linux_nat_create_inferior (struct target_ops *ops,
 			   char *exec_file, char *allargs, char **env,
 			   int from_tty)
 {
-  int saved_async = 0;
 #ifdef HAVE_PERSONALITY
   int personality_orig = 0, personality_set = 0;
 #endif /* HAVE_PERSONALITY */
@@ -1349,11 +1348,6 @@ linux_nat_create_inferior (struct target_ops *ops,
   /* The fork_child mechanism is synchronous and calls target_wait, so
      we have to mask the async mode.  */
 
-  if (target_can_async_p ())
-    /* Mask async mode.  Creating a child requires a loop calling
-       wait_for_inferior currently.  */
-    saved_async = linux_nat_async_mask (0);
-
 #ifdef HAVE_PERSONALITY
   if (disable_randomization)
     {
@@ -1383,9 +1377,6 @@ linux_nat_create_inferior (struct target_ops *ops,
 		 safe_strerror (errno));
     }
 #endif /* HAVE_PERSONALITY */
-
-  if (saved_async)
-    linux_nat_async_mask (saved_async);
 }
 
 static void
@@ -2687,7 +2678,8 @@ linux_nat_filter_event (int lwpid, int status, int options)
 
 static ptid_t
 linux_nat_wait_1 (struct target_ops *ops,
-		  ptid_t ptid, struct target_waitstatus *ourstatus)
+		  ptid_t ptid, struct target_waitstatus *ourstatus,
+		  int target_options)
 {
   static sigset_t prev_mask;
   struct lwp_info *lp = NULL;
@@ -2822,8 +2814,9 @@ retry:
       set_sigint_trap ();
     }
 
-  if (target_can_async_p ())
-    options |= WNOHANG; /* In async mode, don't block.  */
+  /* Translate generic target_wait options into waitpid options.  */
+  if (target_options & TARGET_WNOHANG)
+    options |= WNOHANG;
 
   while (lp == NULL)
     {
@@ -2928,7 +2921,7 @@ retry:
 	     In sync mode, suspend waiting for a SIGCHLD signal.  */
 	  if (options & __WCLONE)
 	    {
-	      if (target_can_async_p ())
+	      if (target_options & TARGET_WNOHANG)
 		{
 		  /* No interesting event.  */
 		  ourstatus->kind = TARGET_WAITKIND_IGNORE;
@@ -3072,7 +3065,8 @@ retry:
 
 static ptid_t
 linux_nat_wait (struct target_ops *ops,
-		ptid_t ptid, struct target_waitstatus *ourstatus)
+		ptid_t ptid, struct target_waitstatus *ourstatus,
+		int target_options)
 {
   ptid_t event_ptid;
 
@@ -3083,7 +3077,7 @@ linux_nat_wait (struct target_ops *ops,
   if (target_can_async_p ())
     async_file_flush ();
 
-  event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus);
+  event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
 
   /* If we requested any event, and something came out, assume there
      may be more.  If we requested a specific lwp or process, also
diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c
index 3efcae8232..3d49484a2b 100644
--- a/gdb/linux-thread-db.c
+++ b/gdb/linux-thread-db.c
@@ -1178,12 +1178,13 @@ check_event (ptid_t ptid)
 
 static ptid_t
 thread_db_wait (struct target_ops *ops,
-		ptid_t ptid, struct target_waitstatus *ourstatus)
+		ptid_t ptid, struct target_waitstatus *ourstatus,
+		int options)
 {
   struct thread_db_info *info;
   struct target_ops *beneath = find_target_beneath (ops);
 
-  ptid = beneath->to_wait (beneath, ptid, ourstatus);
+  ptid = beneath->to_wait (beneath, ptid, ourstatus, options);
 
   if (ourstatus->kind == TARGET_WAITKIND_IGNORE)
     return ptid;
diff --git a/gdb/monitor.c b/gdb/monitor.c
index 1b41a165ef..f77f46f320 100644
--- a/gdb/monitor.c
+++ b/gdb/monitor.c
@@ -1065,7 +1065,7 @@ monitor_wait_filter (char *buf,
 
 static ptid_t
 monitor_wait (struct target_ops *ops,
-	      ptid_t ptid, struct target_waitstatus *status)
+	      ptid_t ptid, struct target_waitstatus *status, int options)
 {
   int old_timeout = timeout;
   char buf[TARGET_BUF_SIZE];
diff --git a/gdb/nto-procfs.c b/gdb/nto-procfs.c
index b46c64d8db..3ff99aab75 100644
--- a/gdb/nto-procfs.c
+++ b/gdb/nto-procfs.c
@@ -623,7 +623,7 @@ nto_interrupt (int signo)
 
 static ptid_t
 procfs_wait (struct target_ops *ops,
-	     ptid_t ptid, struct target_waitstatus *ourstatus)
+	     ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 {
   sigset_t set;
   siginfo_t info;
diff --git a/gdb/record.c b/gdb/record.c
index df59550b86..dfd7487106 100644
--- a/gdb/record.c
+++ b/gdb/record.c
@@ -98,7 +98,8 @@ static void (*record_beneath_to_resume) (struct target_ops *, ptid_t, int,
                                          enum target_signal);
 static struct target_ops *record_beneath_to_wait_ops;
 static ptid_t (*record_beneath_to_wait) (struct target_ops *, ptid_t,
-					 struct target_waitstatus *);
+					 struct target_waitstatus *,
+					 int);
 static struct target_ops *record_beneath_to_store_registers_ops;
 static void (*record_beneath_to_store_registers) (struct target_ops *,
                                                   struct regcache *,
@@ -566,7 +567,8 @@ record_wait_cleanups (void *ignore)
 
 static ptid_t
 record_wait (struct target_ops *ops,
-              ptid_t ptid, struct target_waitstatus *status)
+	     ptid_t ptid, struct target_waitstatus *status,
+	     int options)
 {
   struct cleanup *set_cleanups = record_gdb_operation_disable_set ();
 
@@ -590,7 +592,7 @@ record_wait (struct target_ops *ops,
 	{
 	  /* This is a single step.  */
 	  return record_beneath_to_wait (record_beneath_to_wait_ops,
-                                                      ptid, status);
+					 ptid, status, 0);
 	}
       else
 	{
@@ -601,7 +603,7 @@ record_wait (struct target_ops *ops,
 	  while (1)
 	    {
 	      ret = record_beneath_to_wait (record_beneath_to_wait_ops,
-					    ptid, status);
+					    ptid, status, 0);
 
 	      if (status->kind == TARGET_WAITKIND_STOPPED
 		  && status->value.sig == TARGET_SIGNAL_TRAP)
diff --git a/gdb/remote-mips.c b/gdb/remote-mips.c
index 23e845fd70..926e1d2ab9 100644
--- a/gdb/remote-mips.c
+++ b/gdb/remote-mips.c
@@ -1695,7 +1695,7 @@ mips_signal_from_protocol (int sig)
 
 static ptid_t
 mips_wait (struct target_ops *ops,
-	   ptid_t ptid, struct target_waitstatus *status)
+	   ptid_t ptid, struct target_waitstatus *status, int options)
 {
   int rstatus;
   int err;
diff --git a/gdb/remote-sim.c b/gdb/remote-sim.c
index 4eae65aeca..9b8d0fd7d6 100644
--- a/gdb/remote-sim.c
+++ b/gdb/remote-sim.c
@@ -676,7 +676,7 @@ gdbsim_cntrl_c (int signo)
 
 static ptid_t
 gdbsim_wait (struct target_ops *ops,
-	     ptid_t ptid, struct target_waitstatus *status)
+	     ptid_t ptid, struct target_waitstatus *status, int options)
 {
   static RETSIGTYPE (*prev_sigint) ();
   int sigrc = 0;
diff --git a/gdb/remote.c b/gdb/remote.c
index 60d3204866..199120d553 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -4646,7 +4646,7 @@ process_stop_reply (struct stop_reply *stop_reply,
 /* The non-stop mode version of target_wait.  */
 
 static ptid_t
-remote_wait_ns (ptid_t ptid, struct target_waitstatus *status)
+remote_wait_ns (ptid_t ptid, struct target_waitstatus *status, int options)
 {
   struct remote_state *rs = get_remote_state ();
   struct remote_arch_state *rsa = get_remote_arch_state ();
@@ -4688,16 +4688,15 @@ remote_wait_ns (ptid_t ptid, struct target_waitstatus *status)
       if (stop_reply != NULL)
 	return process_stop_reply (stop_reply, status);
 
-      /* Still no event.  If we're in asynchronous mode, then just
+      /* Still no event.  If we're just polling for an event, then
 	 return to the event loop.  */
-      if (remote_is_async_p ())
+      if (options & TARGET_WNOHANG)
 	{
 	  status->kind = TARGET_WAITKIND_IGNORE;
 	  return minus_one_ptid;
 	}
 
-      /* Otherwise, asynchronous mode is masked, so do a blocking
-	 wait.  */
+      /* Otherwise do a blocking wait.  */
       ret = getpkt_or_notif_sane (&rs->buf, &rs->buf_size,
 				  1 /* forever */);
     }
@@ -4707,7 +4706,7 @@ remote_wait_ns (ptid_t ptid, struct target_waitstatus *status)
    STATUS just as `wait' would.  */
 
 static ptid_t
-remote_wait_as (ptid_t ptid, struct target_waitstatus *status)
+remote_wait_as (ptid_t ptid, struct target_waitstatus *status, int options)
 {
   struct remote_state *rs = get_remote_state ();
   struct remote_arch_state *rsa = get_remote_arch_state ();
@@ -4717,6 +4716,8 @@ remote_wait_as (ptid_t ptid, struct target_waitstatus *status)
   char *buf, *p;
   struct stop_reply *stop_reply;
 
+ again:
+
   status->kind = TARGET_WAITKIND_IGNORE;
   status->value.integer = 0;
 
@@ -4819,8 +4820,14 @@ remote_wait_as (ptid_t ptid, struct target_waitstatus *status)
     }
 
   if (status->kind == TARGET_WAITKIND_IGNORE)
-    /* Nothing interesting happened.  */
-    return minus_one_ptid;
+    {
+      /* Nothing interesting happened.  If we're doing a non-blocking
+	 poll, we're done.  Otherwise, go back to waiting.  */
+      if (options & TARGET_WNOHANG)
+	return minus_one_ptid;
+      else
+	goto again;
+    }
   else if (status->kind != TARGET_WAITKIND_EXITED
 	   && status->kind != TARGET_WAITKIND_SIGNALLED)
     {
@@ -4841,24 +4848,14 @@ remote_wait_as (ptid_t ptid, struct target_waitstatus *status)
 
 static ptid_t
 remote_wait (struct target_ops *ops,
-	     ptid_t ptid, struct target_waitstatus *status)
+	     ptid_t ptid, struct target_waitstatus *status, int options)
 {
   ptid_t event_ptid;
 
   if (non_stop)
-    event_ptid = remote_wait_ns (ptid, status);
+    event_ptid = remote_wait_ns (ptid, status, options);
   else
-    {
-      /* In synchronous mode, keep waiting until the target stops.  In
-	 asynchronous mode, always return to the event loop.  */
-
-      do
-	{
-	  event_ptid = remote_wait_as (ptid, status);
-	}
-      while (status->kind == TARGET_WAITKIND_IGNORE
-	     && !target_can_async_p ());
-    }
+    event_ptid = remote_wait_as (ptid, status, options);
 
   if (target_can_async_p ())
     {
diff --git a/gdb/rs6000-nat.c b/gdb/rs6000-nat.c
index 8aeef25b5c..92bbabd872 100644
--- a/gdb/rs6000-nat.c
+++ b/gdb/rs6000-nat.c
@@ -521,7 +521,7 @@ rs6000_xfer_partial (struct target_ops *ops, enum target_object object,
 
 static ptid_t
 rs6000_wait (struct target_ops *ops,
-	     ptid_t ptid, struct target_waitstatus *ourstatus)
+	     ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 {
   pid_t pid;
   int status, save_errno;
diff --git a/gdb/sol-thread.c b/gdb/sol-thread.c
index cf085f0c24..028e036eb6 100644
--- a/gdb/sol-thread.c
+++ b/gdb/sol-thread.c
@@ -381,7 +381,7 @@ sol_thread_resume (struct target_ops *ops,
 
 static ptid_t
 sol_thread_wait (struct target_ops *ops,
-		 ptid_t ptid, struct target_waitstatus *ourstatus)
+		 ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 {
   ptid_t rtnval;
   ptid_t save_ptid;
@@ -407,7 +407,7 @@ sol_thread_wait (struct target_ops *ops,
 		 GET_THREAD (save_ptid));
     }
 
-  rtnval = beneath->to_wait (beneath, ptid, ourstatus);
+  rtnval = beneath->to_wait (beneath, ptid, ourstatus, options);
 
   if (ourstatus->kind != TARGET_WAITKIND_EXITED)
     {
diff --git a/gdb/spu-linux-nat.c b/gdb/spu-linux-nat.c
index 3b1e337850..b8897e188f 100644
--- a/gdb/spu-linux-nat.c
+++ b/gdb/spu-linux-nat.c
@@ -422,7 +422,7 @@ spu_child_post_attach (int pid)
    minus_one_ptid in case of error; store status into *OURSTATUS.  */
 static ptid_t
 spu_child_wait (struct target_ops *ops,
-		ptid_t ptid, struct target_waitstatus *ourstatus)
+		ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 {
   int save_errno;
   int status;
diff --git a/gdb/target.c b/gdb/target.c
index 506fce710d..8cbde1b91e 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -1836,7 +1836,7 @@ target_disconnect (char *args, int from_tty)
 }
 
 ptid_t
-target_wait (ptid_t ptid, struct target_waitstatus *status)
+target_wait (ptid_t ptid, struct target_waitstatus *status, int options)
 {
   struct target_ops *t;
 
@@ -1844,7 +1844,7 @@ target_wait (ptid_t ptid, struct target_waitstatus *status)
     {
       if (t->to_wait != NULL)
 	{
-	  ptid_t retval = (*t->to_wait) (t, ptid, status);
+	  ptid_t retval = (*t->to_wait) (t, ptid, status, options);
 
 	  if (targetdebug)
 	    {
diff --git a/gdb/target.h b/gdb/target.h
index b94149ab99..5ec06a08e6 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -153,6 +153,13 @@ struct target_waitstatus
     value;
   };
 
+/* Options that can be passed to target_wait.  */
+
+/* Return immediately if there's no event already queued.  If this
+   options is not requested, target_wait blocks waiting for an
+   event.  */
+#define TARGET_WNOHANG 1
+
 /* Return a pretty printed form of target_waitstatus.
    Space for the result is malloc'd, caller must free.  */
 extern char *target_waitstatus_to_string (const struct target_waitstatus *);
@@ -327,7 +334,7 @@ struct target_ops
     void (*to_disconnect) (struct target_ops *, char *, int);
     void (*to_resume) (struct target_ops *, ptid_t, int, enum target_signal);
     ptid_t (*to_wait) (struct target_ops *,
-		      ptid_t, struct target_waitstatus *);
+		       ptid_t, struct target_waitstatus *, int);
     void (*to_fetch_registers) (struct target_ops *, struct regcache *, int);
     void (*to_store_registers) (struct target_ops *, struct regcache *, int);
     void (*to_prepare_to_store) (struct regcache *);
@@ -621,9 +628,11 @@ extern void target_resume (ptid_t ptid, int step, enum target_signal signal);
    _NOT_ OK to throw_exception() out of target_wait() without popping
    the debugging target from the stack; GDB isn't prepared to get back
    to the prompt with a debugging target but without the frame cache,
-   stop_pc, etc., set up.  */
+   stop_pc, etc., set up.  OPTIONS is a bitwise OR of TARGET_W*
+   options.  */
 
-extern ptid_t target_wait (ptid_t ptid, struct target_waitstatus *status);
+extern ptid_t target_wait (ptid_t ptid, struct target_waitstatus *status,
+			   int options);
 
 /* Fetch at least register REGNO, or all regs if regno == -1.  No result.  */
 
diff --git a/gdb/top.c b/gdb/top.c
index 5654535453..ba635eaa64 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -266,7 +266,8 @@ void (*deprecated_memory_changed_hook) (CORE_ADDR addr, int len);
    while waiting for target events.  */
 
 ptid_t (*deprecated_target_wait_hook) (ptid_t ptid,
-				       struct target_waitstatus * status);
+				       struct target_waitstatus *status,
+				       int options);
 
 /* Used by UI as a wrapper around command execution.  May do various things
    like enabling/disabling buttons, etc...  */
diff --git a/gdb/tui/tui-hooks.c b/gdb/tui/tui-hooks.c
index aa4ecca2bd..7dee03e47e 100644
--- a/gdb/tui/tui-hooks.c
+++ b/gdb/tui/tui-hooks.c
@@ -160,7 +160,7 @@ tui_event_modify_breakpoint (int number)
    Leave curses mode and setup program mode.  */
 static ptid_t
 tui_target_wait_hook (ptid_t pid, 
-		      struct target_waitstatus *status)
+		      struct target_waitstatus *status, int options)
 {
   ptid_t res;
 
@@ -174,7 +174,7 @@ tui_target_wait_hook (ptid_t pid,
     }
 #endif
   tui_target_has_run = 1;
-  res = target_wait (pid, status);
+  res = target_wait (pid, status, options);
 
   if (tui_active)
     {
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index 5b9b6f9700..32a412664e 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -1494,7 +1494,7 @@ out:
 /* Wait for interesting events to occur in the target process.  */
 static ptid_t
 windows_wait (struct target_ops *ops,
-	      ptid_t ptid, struct target_waitstatus *ourstatus)
+	      ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 {
   int pid = -1;
 
-- 
2.34.1