[PATCH/SPARC-branch] Make call dummies on non-executable stack work

[Mark Kettenis <kettenis at chello dot nl>]

The attached patch makes call dummies on a non-executable stack
working.  I checked this in on my SPARC branch.  What do people think
about checking this in on mainline?  I don't thinkthis will get much
exposure on the branch.

Mark

Index: ChangeLog
from  Mark Kettenis  <kettenis@gnu.org>

	* infrun.c (handle_inferior_event): Allow for breakpoint
	instructions to generate a SIGSEGV in addition to SIGTRAP, SIGILL
	and SIGEMT.  Update comments.

Index: infrun.c
===================================================================
RCS file: /cvs/src/src/gdb/infrun.c,v
retrieving revision 1.113
diff -u -p -r1.113 infrun.c
--- infrun.c 14 Sep 2003 16:32:13 -0000 1.113
+++ infrun.c 15 Oct 2003 19:54:43 -0000
@@ -1845,16 +1845,21 @@ handle_inferior_event (struct execution_
      will be made according to the signal handling tables.  */
 
   /* First, distinguish signals caused by the debugger from signals
-     that have to do with the program's own actions.
-     Note that breakpoint insns may cause SIGTRAP or SIGILL
-     or SIGEMT, depending on the operating system version.
-     Here we detect when a SIGILL or SIGEMT is really a breakpoint
-     and change it to SIGTRAP.  */
+     that have to do with the program's own actions.  Note that
+     breakpoint insns may cause SIGTRAP or SIGILL or SIGEMT, depending
+     on the operating system version.  Here we detect when a SIGILL or
+     SIGEMT is really a breakpoint and change it to SIGTRAP.  We do
+     something similar for SIGSEGV, since a SIGSEGV will be generated
+     when we're trying to execute a breakpoint instruction on a
+     non-executable stack.  This happens for call dummy breakpoints
+     for architectures like SPARC that place call dummies on the
+     stack.  */
 
   if (stop_signal == TARGET_SIGNAL_TRAP
       || (breakpoints_inserted &&
 	  (stop_signal == TARGET_SIGNAL_ILL
-	   || stop_signal == TARGET_SIGNAL_EMT))
+	   || stop_signal == TARGET_SIGNAL_EMT
+	   || stop_signal == TARGET_SIGNAL_SEGV))
       || stop_soon == STOP_QUIETLY
       || stop_soon == STOP_QUIETLY_NO_SIGSTOP)
     {
@@ -1937,10 +1942,14 @@ handle_inferior_event (struct execution_
 
          If someone ever tries to get get call dummys on a
          non-executable stack to work (where the target would stop
-         with something like a SIGSEG), then those tests might need to
-         be re-instated.  Given, however, that the tests were only
+         with something like a SIGSEGV), then those tests might need
+         to be re-instated.  Given, however, that the tests were only
          enabled when momentary breakpoints were not being used, I
-         suspect that it won't be the case.  */
+         suspect that it won't be the case.
+
+	 NOTE: kettenis/2003-10-15: Indeed such checks don't seem to
+	 be necessary for call dummies on a non-executable stack on
+	 SPARC.  */
 
       if (stop_signal == TARGET_SIGNAL_TRAP)
 	ecs->random_signal