[jankratochvil-misc] Fix a completer regression if you link gdbwith -lmcheck

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Fix a regression if you link gdb with -lmcheck:
-PASS: gdb.base/completion.exp: complete 'p values[0].a'
-PASS: gdb.base/completion.exp: complete 'p values[0] . a'
-PASS: gdb.base/completion.exp: complete 'p &values[0] -> a'
-PASS: gdb.base/completion.exp: cd to ${srcdir}
+FAIL: gdb.base/completion.exp: (timeout) complete 'p values[0].a' 2
+FAIL: gdb.base/completion.exp: (timeout) complete 'p values[0] . a' 2
+FAIL: gdb.base/completion.exp: (timeout) complete 'p &values[0] -> a' 2
+FAIL: gdb.base/completion.exp: cd to ${srcdir}

2008-11-22  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Fix access of an already freed memory.
	* parse.c (parse_field_expression): Call xstrdup on `*name'.
	* completer.c (expression_completer): Free fieldname.
---
 gdb/completer.c |    2 ++
 gdb/parse.c     |    6 +++++-
 2 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/gdb/completer.c b/gdb/completer.c
index e7ee817..d109140 100644
--- a/gdb/completer.c
+++ b/gdb/completer.c
@@ -414,9 +414,11 @@ expression_completer (char *text, char *word)
 
 	  add_struct_fields (type, &out, result, fieldname, flen);
 	  result[out] = NULL;
+	  xfree (fieldname);
 	  return result;
 	}
     }
+  xfree (fieldname);
 
   /* Commands which complete on locations want to see the entire
      argument.  */
diff --git a/gdb/parse.c b/gdb/parse.c
index 6200e81..3575306 100644
--- a/gdb/parse.c
+++ b/gdb/parse.c
@@ -1090,7 +1090,8 @@ parse_expression (char *string)
 /* Parse STRING as an expression.  If parsing ends in the middle of a
    field reference, return the type of the left-hand-side of the
    reference; furthermore, if the parsing ends in the field name,
-   return the field name in *NAME.  In all other cases, return NULL.  */
+   return the field name in *NAME.  In all other cases, return NULL.
+   Returned non-NULL *NAME must be freed by the caller.  */
 
 struct type *
 parse_field_expression (char *string, char **name)
@@ -1120,6 +1121,9 @@ parse_field_expression (char *string, char **name)
       xfree (exp);
       return NULL;
     }
+  /* (*NAME) is a part of the EXP memory block freed below.  */
+  *name = xstrdup (*name);
+
   val = evaluate_subexpression_type (exp, subexp);
   xfree (exp);
 
-- 
1.6.0.3