[reverse RFA] no singlestep-over-BP in reverse

[Michael Snyder <msnyder@vmware.com>]

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When we're stopped at a breakpoint and we want to
continue in reverse, we're not actually going to
execute the instruction at the breakpoint -- we're
going to de-execute the previous instruction.

Therefore there's no need to singlestep before
inserting breakpoints.  In fact it would be a bad
idea to do so, because if there is a breakpoint at
the previous instruction, we WANT to hit it.

Note that this patch is to be applied to the reverse branch.

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2008-09-15  Michael Snyder  <msnyder@vmware.com>

	* infrun.c (proceed): No need to singlestep over a breakpoint
	when resuming in reverse.

Index: infrun.c
===================================================================
RCS file: /cvs/src/src/gdb/infrun.c,v
retrieving revision 1.300.2.5
diff -u -p -r1.300.2.5 infrun.c
--- infrun.c	5 Sep 2008 03:37:10 -0000	1.300.2.5
+++ infrun.c	15 Sep 2008 18:28:29 -0000
@@ -1226,11 +1226,17 @@ proceed (CORE_ADDR addr, enum target_sig
 
   if (addr == (CORE_ADDR) -1)
     {
-      if (pc == stop_pc && breakpoint_here_p (pc))
+      if (pc == stop_pc && breakpoint_here_p (pc) 
+	  && target_get_execution_direction () == EXEC_FORWARD)
 	/* There is a breakpoint at the address we will resume at,
 	   step one instruction before inserting breakpoints so that
 	   we do not stop right away (and report a second hit at this
-	   breakpoint).  */
+	   breakpoint).
+
+	   Note, we don't do this in reverse, because we won't
+	   actually be executing the breakpoint insn anyway.
+	   We'll be (un-)executing the previous instruction.  */
+
 	oneproc = 1;
       else if (gdbarch_single_step_through_delay_p (gdbarch)
 	       && gdbarch_single_step_through_delay (gdbarch,