* DevNotes: Add entry cgf-000025.

* exceptions.cc (_cygtls::signal_debugger): Reorganize to avoid contacting the
debugger if we have already done so via the exception handler.  Eliminate need
for goto.  Remove an ifdef in favor of just allocating a larger buffer.

3 files changed, 30 insertions, 27 deletions

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 1713b98..faf5c36 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,11 @@
+2014-03-29  Christopher Faylor  <me.cygwin2014@cgf.cx>
+
+	* DevNotes: Add entry cgf-000025.
+	* exceptions.cc (_cygtls::signal_debugger): Reorganize to avoid
+	contacting the debugger if we have already done so via the exception
+	handler.  Eliminate need for goto.  Remove an ifdef in favor of just
+	allocating a larger buffer.
+
 2014-03-28  Corinna Vinschen  <corinna@vinschen.de>
 
 	* dcrt0.cc (dll_crt0_0): Install myfault exception handler on x86_64.
diff --git a/winsup/cygwin/DevNotes b/winsup/cygwin/DevNotes
index b8820a9..0f48095 100644
--- a/winsup/cygwin/DevNotes
+++ b/winsup/cygwin/DevNotes
@@ -1,3 +1,11 @@
+2014-03-29  cgf-000025
+
+Reorganized _cygtls::signal_debugger to avoid sending anything to the
+debugger if we've seen an exception.  I think it used to work that way
+and I changed it without noting why.  It sure seems like, if we don't do
+this, gdb will see two signals and, it really does, when there has been
+a Windows-recognized exception.
+
 2014-02-15  cgf-000024
 
 Wow.  It's hard getting the screen handling stuff working correctly when
diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index c288913..120d71b 100644
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -1461,42 +1461,29 @@ _cygtls::call_signal_handler ()
 void
 _cygtls::signal_debugger (siginfo_t& si)
 {
-  HANDLE th = NULL;
-  if (isinitialized () && being_debugged ())
+  HANDLE th;
+  /* If si.si_cyg is set then the signal was already sent to the debugger. */
+  if (isinitialized () && !si.si_cyg && (th = (HANDLE) *this)
+      && being_debugged () && SuspendThread (th) >= 0)
     {
       CONTEXT c;
-      CONTEXT *pc;
-
-      if (si.si_cyg)
-	pc = ((cygwin_exception *) si.si_cyg)->context ();
-      else if (!(th = (HANDLE) *this))
-	return;
-      else
+      c.ContextFlags = CONTEXT_FULL;
+      if (GetThreadContext (th, &c))
 	{
-	  SuspendThread (th);
-	  c.ContextFlags = CONTEXT_FULL;
-	  if (!GetThreadContext (th, &c))
-	    goto out;
 	  if (incyg)
 #ifdef __x86_64__
 	    c.Rip = retaddr ();
 #else
 	    c.Eip = retaddr ();
 #endif
-	  pc = &c;
+	  memcpy (&thread_context, &c, (&thread_context._internal -
+					(unsigned char *) &thread_context));
+	  /* Enough space for 32/64 bit addresses */
+	  char sigmsg[2 * sizeof (_CYGWIN_SIGNAL_STRING " ffffffff ffffffffffffffff")];
+	  __small_sprintf (sigmsg, _CYGWIN_SIGNAL_STRING " %d %y %p", si.si_signo,
+			   thread_id, &thread_context);
+	  OutputDebugString (sigmsg);
 	}
-      memcpy (&thread_context, pc, (&thread_context._internal -
-				    (unsigned char *) &thread_context));
-#ifdef __x86_64__
-      char sigmsg[2 * sizeof (_CYGWIN_SIGNAL_STRING " ffffffff ffffffffffffffff")];
-#else
-      char sigmsg[2 * sizeof (_CYGWIN_SIGNAL_STRING " ffffffff ffffffff")];
-#endif
-      __small_sprintf (sigmsg, _CYGWIN_SIGNAL_STRING " %d %y %p", si.si_signo,
-		       thread_id, &thread_context);
-      OutputDebugString (sigmsg);
+      ResumeThread (th);
     }
-out:
-  if (th)
-    ResumeThread (th);
 }