[ob] Fix two memory corruption bugs

[Daniel Jacobowitz <drow at false dot org>]

I encountered a crash in watchpoint.exp on our local branch.  That
branch has an ARM patch we'll be posting soon to support VFP.  That
in turn causes arm_return_value to use the supplied type argument -
which was corrupt.  That's because the code in
bpstat_check_breakpoint_conditions has freed values during proceed,
so the function value supplied to call_function_by_hand was
invalidated.  There's another place in breakpoint.c which uses
value_mark to avoid this problem, so duplicate it here.

I tracked it down under valgrind, which located the objfiles.c bug;
ARM's clear_objfile_data hook uses objfile->obfd which had already
been freed.

I've tested this on x86_64 and ARM, both Linux, and checked it in.

-- 
Daniel Jacobowitz
CodeSourcery

2009-03-11  Daniel Jacobowitz  <dan@codesourcery.com>

	* breakpoint.c (bpstat_check_breakpoint_conditions): Use
	value_mark and value_free_to_mark.
	* objfiles.c (free_objfile): Call objfile_free_data before
	freeing the BFD.

Index: breakpoint.c
===================================================================
RCS file: /cvs/src/src/gdb/breakpoint.c,v
retrieving revision 1.382
diff -u -p -r1.382 breakpoint.c
--- breakpoint.c	6 Mar 2009 18:51:05 -0000	1.382
+++ breakpoint.c	11 Mar 2009 20:17:37 -0000
@@ -2882,6 +2882,13 @@ bpstat_check_breakpoint_conditions (bpst
       
       if (bl->cond && bl->owner->disposition != disp_del_at_next_stop)
 	{
+	  /* We use value_mark and value_free_to_mark because it could
+	     be a long time before we return to the command level and
+	     call free_all_values.  We can't call free_all_values
+	     because we might be in the middle of evaluating a
+	     function call.  */
+	  struct value *mark = value_mark ();
+
 	  /* Need to select the frame, with all that implies
 	     so that the conditions will have the right context.  */
 	  select_frame (get_current_frame ());
@@ -2890,7 +2897,7 @@ bpstat_check_breakpoint_conditions (bpst
 			    "Error in testing breakpoint condition:\n",
 			    RETURN_MASK_ALL);
 	  /* FIXME-someday, should give breakpoint # */
-	  free_all_values ();
+	  value_free_to_mark (mark);
 	}
       if (bl->cond && value_is_zero)
 	{
Index: objfiles.c
===================================================================
RCS file: /cvs/src/src/gdb/objfiles.c,v
retrieving revision 1.81
diff -u -p -r1.81 objfiles.c
--- objfiles.c	15 Jan 2009 16:35:22 -0000	1.81
+++ objfiles.c	11 Mar 2009 20:17:37 -0000
@@ -422,6 +422,9 @@ free_objfile (struct objfile *objfile)
       (*objfile->sf->sym_finish) (objfile);
     }
 
+  /* Discard any data modules have associated with the objfile.  */
+  objfile_free_data (objfile);
+
   /* We always close the bfd, unless the OBJF_KEEPBFD flag is set.  */
 
   if (objfile->obfd != NULL && !(objfile->flags & OBJF_KEEPBFD))
@@ -476,7 +479,6 @@ free_objfile (struct objfile *objfile)
 
   /* The last thing we do is free the objfile struct itself. */
 
-  objfile_free_data (objfile);
   if (objfile->name != NULL)
     {
       xfree (objfile->name);