Introduce gdb-hashtab module in gdbsupport

gdb has some extensions and helpers for working with the libiberty
hash table.  This patch consolidates these and moves them to
gdbsupport.

1 files changed, 44 insertions, 0 deletions

diff --git a/gdbsupport/gdb-hashtab.cc b/gdbsupport/gdb-hashtab.cc
new file mode 100644
index 0000000..c42e8fe
--- /dev/null
+++ b/gdbsupport/gdb-hashtab.cc
@@ -0,0 +1,44 @@
+/* Hash table wrappers for gdb.
+   Copyright (C) 2021 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "common-defs.h"
+#include "gdb-hashtab.h"
+
+/* Allocation function for the libiberty hash table which uses an
+   obstack.  The obstack is passed as DATA.  */
+
+void *
+hashtab_obstack_allocate (void *data, size_t size, size_t count)
+{
+  size_t total = size * count;
+  void *ptr = obstack_alloc ((struct obstack *) data, total);
+
+  memset (ptr, 0, total);
+  return ptr;
+}
+
+/* Trivial deallocation function for the libiberty splay tree and hash
+   table - don't deallocate anything.  Rely on later deletion of the
+   obstack.  DATA will be the obstack, although it is not needed
+   here.  */
+
+void
+dummy_obstack_deallocate (void *object, void *data)
+{
+  return;
+}