[PATCH][PR symtab/17855] Fix.

[Doug Evans <xdje42@gmail.com>]

Hi.

This patch fixes symtab/17855.
Basically the issue is that breakpoint_re_set is currently being called
before observer_notify_new_objfile (NULL), and thus the ada symbol
cache (and the general symbol cache of a separate patch) aren't being
flushed first, so that when breakpoints are reset symbol lookup is being
done on a stale cache.

Regression tested on amd64-linux.

2015-01-19  Doug Evans  <xdje42@gmail.com>

	PR symtab/17855
	* symfile.c (clear_symtab_users): Notify observers of change before
	calling breakpoint_re_set.

diff --git a/gdb/symfile.c b/gdb/symfile.c
index d55e361..ad481de 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -3023,6 +3023,12 @@ clear_symtab_users (int add_flags)
   /* Someday, we should do better than this, by only blowing away
      the things that really need to be blown.  */
 
+  /* Notify anyone listening that the previous loaded symtab(s) are invalid.
+     It is important to do this before calling breakpoint_re_set as the latter
+     will try to look up symbols, and for example the symbol cache needs to
+     be flushed first.  */
+  observer_notify_new_objfile (NULL);
+
   /* Clear the "current" symtab first, because it is no longer valid.
      breakpoint_re_set may try to access the current symtab.  */
   clear_current_source_symtab_and_line ();
@@ -3032,7 +3038,6 @@ clear_symtab_users (int add_flags)
     breakpoint_re_set ();
   clear_last_displayed_sal ();
   clear_pc_function_cache ();
-  observer_notify_new_objfile (NULL);
 
   /* Clear globals which might have pointed into a removed objfile.
      FIXME: It's not clear which of these are supposed to persist