Remove more calls to xfree from Python

This changes the Python code to remove some more calls to xfree, in
favor of self-managing data structures.

Tested on x86-64 Fedora 28.

gdb/ChangeLog
2018-12-27  Tom Tromey  <tom@tromey.com>

	* python/python.c (python_interactive_command): Use std::string.
	(gdbpy_parameter): Likewise.
	* python/py-utils.c (unicode_to_encoded_string): Update comment.
	* python/py-symtab.c (salpy_str): Use PyString_FromFormat.
	* python/py-record-btrace.c (recpy_bt_insn_data): Use
	byte_vector.
	* python/py-objfile.c (objfpy_get_build_id): Use
	unique_xmalloc_ptr.
	* python/py-inferior.c (infpy_read_memory): Use
	unique_xmalloc_ptr.
	* python/py-cmd.c (gdbpy_parse_command_name): Use std::string.

1 files changed, 4 insertions, 10 deletions

diff --git a/gdb/python/py-cmd.c b/gdb/python/py-cmd.c
index d560b3a..0e39730 100644
--- a/gdb/python/py-cmd.c
+++ b/gdb/python/py-cmd.c
@@ -362,7 +362,6 @@ gdbpy_parse_command_name (const char *name,
   struct cmd_list_element *elt;
   int len = strlen (name);
   int i, lastchar;
-  char *prefix_text;
   const char *prefix_text2;
   char *result;
 
@@ -395,31 +394,26 @@ gdbpy_parse_command_name (const char *name,
       return result;
     }
 
-  prefix_text = (char *) xmalloc (i + 2);
-  memcpy (prefix_text, name, i + 1);
-  prefix_text[i + 1] = '\0';
+  std::string prefix_text (name, i + 1);
 
-  prefix_text2 = prefix_text;
+  prefix_text2 = prefix_text.c_str ();
   elt = lookup_cmd_1 (&prefix_text2, *start_list, NULL, 1);
   if (elt == NULL || elt == CMD_LIST_AMBIGUOUS)
     {
       PyErr_Format (PyExc_RuntimeError, _("Could not find command prefix %s."),
-		    prefix_text);
-      xfree (prefix_text);
+		    prefix_text.c_str ());
       xfree (result);
       return NULL;
     }
 
   if (elt->prefixlist)
     {
-      xfree (prefix_text);
       *base_list = elt->prefixlist;
       return result;
     }
 
   PyErr_Format (PyExc_RuntimeError, _("'%s' is not a prefix command."),
-		prefix_text);
-  xfree (prefix_text);
+		prefix_text.c_str ());
   xfree (result);
   return NULL;
 }