[RFC v5 1/8] fix latent bugs in ui-out.c

[Tom Tromey <tromey@redhat.com>]

The destructor code in ui-out.c has a latent bug, which is hidden by
the fact that nothing uses this right now.  This patch fixes the
problem.  The bug is that we don't always clear a pointer in the
ui-out object, leading to a bad free.

2013-10-30  Tom Tromey  <tromey@redhat.com>

	* ui-out.c (clear_table, ui_out_new): Clear uiout->table.id.
---
 gdb/ChangeLog | 4 ++++
 gdb/ui-out.c  | 5 +++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/gdb/ui-out.c b/gdb/ui-out.c
index 2edb140..63cbc6e 100644
--- a/gdb/ui-out.c
+++ b/gdb/ui-out.c
@@ -807,8 +807,8 @@ uo_table_header (struct ui_out *uiout, int width, enum ui_align align,
 static void
 clear_table (struct ui_out *uiout)
 {
-  if (uiout->table.id)
-    xfree (uiout->table.id);
+  xfree (uiout->table.id);
+  uiout->table.id = NULL;
   clear_header_list (uiout);
 }
 
@@ -1114,6 +1114,7 @@ ui_out_new (const struct ui_out_impl *impl, void *data,
   current->field_count = 0;
   VEC_safe_push (ui_out_level_p, uiout->levels, current);
 
+  uiout->table.id = NULL;
   uiout->table.header_first = NULL;
   uiout->table.header_last = NULL;
   uiout->table.header_next = NULL;
-- 
1.8.1.4