[RFA Darwin]: handle simultaneous signal posting and single-stepping

[Tristan Gingold <gingold at adacore dot com>]

Hi,

in some cases (when a signal was received when the execution was  
stopped on a breakpoint), gdb resumes the
inferior with both step=1 and signal != 0.  This case wasn't handled  
correctly by darwin-nat (as the native
API isn't able to do that).

This patch fixes the issue by first single-stepping and keeping in  
mind that a signal has to be posted.

This patch fixes about 10 regressions (that resulted in timeout).

Tristan.

2009-07-07  Tristan Gingold  <gingold@adacore.com>

	* darwin-nat.c (darwin_resume_thread): Handle simultaneous single-step
	and signal.
	* darwin-nat.h (struct private_thread_info): Add signal_to_send field.
	Improve comment.


Index: darwin-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/darwin-nat.c,v
retrieving revision 1.13
diff -u -p -r1.13 darwin-nat.c
--- darwin-nat.c	22 Jun 2009 08:24:29 -0000	1.13
+++ darwin-nat.c	7 Jul 2009 08:50:45 -0000
@@ -640,6 +640,19 @@ darwin_resume_thread (struct inferior *i
     (3, _("darwin_resume_thread: state=%d, thread=0x%x, step=%d  
nsignal=%d\n"),
      thread->msg_state, thread->gdb_port, step, nsignal);

+  if (step && nsignal)
+    {
+      /* We can't handle this in one step.  The expected behaviour is  
single
+         step first and then post the signal.  */
+      thread->signal_to_send = nsignal;
+      nsignal = 0;
+    }
+  else if (thread->signal_to_send && !step)
+    {
+      nsignal = thread->signal_to_send;
+      thread->signal_to_send = 0;
+    }
+
   switch (thread->msg_state)
     {
     case DARWIN_MESSAGE:
Index: darwin-nat.h
===================================================================
RCS file: /cvs/src/src/gdb/darwin-nat.h,v
retrieving revision 1.3
diff -u -p -r1.3 darwin-nat.h
--- darwin-nat.h	19 Jun 2009 14:30:30 -0000	1.3
+++ darwin-nat.h	7 Jul 2009 08:50:45 -0000
@@ -80,9 +80,13 @@ struct private_thread_info
   /* True if this thread is single-stepped.  */
   unsigned char single_step;

-  /* True if a signal was manually sent to the thread.  */
+  /* True if a signal was manually sent to the thread.  In this case,  
we don't
+     report that a signal was posted.  */
   unsigned char signaled;

+  /* Signal to be sent.  Used to handle simultaneous step and  
signal.  */
+  unsigned char signal_to_send;
+
   /* The last exception received.  */
   struct darwin_exception_msg event;
 };