Clean up demangle_parse_info

This changes demangle_parse_info to use inline initializers and to
remove some manual memory management.

Approved-By: John Baldwin <jhb@FreeBSD.org>

gdb/cp-name-parser.y

diff --git a/gdb/cp-name-parser.y b/gdb/cp-name-parser.y
index 7820053..e4534ce 100644
--- a/gdb/cp-name-parser.y
+++ b/gdb/cp-name-parser.y
@@ -1955,15 +1955,6 @@
   return gdb::unique_xmalloc_ptr<char> (res);
 }
 
-/* Constructor for demangle_parse_info.  */
-
-demangle_parse_info::demangle_parse_info ()
-: info (NULL),
-  tree (NULL)
-{
-  obstack_init (&obstack);
-}
-
 /* Destructor for demangle_parse_info.  */
 
 demangle_parse_info::~demangle_parse_info ()
@@ -1976,9 +1967,6 @@
       free (info);
       info = next;
     }
-
-  /* Free any memory allocated during typedef replacement.  */
-  obstack_free (&obstack, NULL);
 }
 
 /* Merge the two parse trees given by DEST and SRC.  The parse tree

gdb/cp-support.h

diff --git a/gdb/cp-support.h b/gdb/cp-support.h
index 4015126..d0bedcd 100644
--- a/gdb/cp-support.h
+++ b/gdb/cp-support.h
@@ -58,18 +58,18 @@ struct using_direct;
 
 struct demangle_parse_info
 {
-  demangle_parse_info ();
+  demangle_parse_info () = default;
 
   ~demangle_parse_info ();
 
   /* The memory used during the parse.  */
-  struct demangle_info *info;
+  struct demangle_info *info = nullptr;
 
   /* The result of the parse.  */
-  struct demangle_component *tree;
+  struct demangle_component *tree = nullptr;
 
   /* Any temporary memory used during typedef replacement.  */
-  struct obstack obstack;
+  auto_obstack obstack;
 };