diff --git a/libdw/libdw_form.c b/libdw/libdw_form.c
new file mode 100644
index 0000000..72e2390
--- /dev/null
+++ b/libdw/libdw_form.c
@@ -0,0 +1,132 @@
+/* Helper functions for form handling.
+   Copyright (C) 2003-2009, 2014 Red Hat, Inc.
+   This file is part of elfutils.
+   Written by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   elfutils 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 copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <dwarf.h>
+#include <string.h>
+
+#include "libdwP.h"
+
+
+size_t
+internal_function
+__libdw_form_val_compute_len (struct Dwarf_CU *cu, unsigned int form,
+			      const unsigned char *valp)
+{
+  const unsigned char *startp = valp;
+  const unsigned char *endp = cu->endp;
+  Dwarf_Word u128;
+  size_t result;
+
+  /* NB: This doesn't cover constant form lengths, which are
+     already handled by the inlined __libdw_form_val_len.  */
+  switch (form)
+    {
+    case DW_FORM_addr:
+      result = cu->address_size;
+      break;
+
+    case DW_FORM_ref_addr:
+      result = cu->version == 2 ? cu->address_size : cu->offset_size;
+      break;
+
+    case DW_FORM_strp:
+    case DW_FORM_sec_offset:
+    case DW_FORM_GNU_ref_alt:
+    case DW_FORM_GNU_strp_alt:
+      result = cu->offset_size;
+      break;
+
+    case DW_FORM_block1:
+      if (unlikely ((size_t) (endp - startp) < 1))
+	goto invalid;
+      result = *valp + 1;
+      break;
+
+    case DW_FORM_block2:
+      if (unlikely ((size_t) (endp - startp) < 2))
+	goto invalid;
+      result = read_2ubyte_unaligned (cu->dbg, valp) + 2;
+      break;
+
+    case DW_FORM_block4:
+      if (unlikely ((size_t) (endp - startp) < 4))
+	goto invalid;
+      result = read_4ubyte_unaligned (cu->dbg, valp) + 4;
+      break;
+
+    case DW_FORM_block:
+    case DW_FORM_exprloc:
+      get_uleb128 (u128, valp, endp);
+      result = u128 + (valp - startp);
+      break;
+
+    case DW_FORM_string:
+      {
+	const unsigned char *endstrp = memchr (valp, '\0',
+					       (size_t) (endp - startp));
+	if (unlikely (endstrp == NULL))
+	  goto invalid;
+	result = (size_t) (endstrp - startp) + 1;
+	break;
+      }
+
+    case DW_FORM_sdata:
+    case DW_FORM_udata:
+    case DW_FORM_ref_udata:
+      get_uleb128 (u128, valp, endp);
+      result = valp - startp;
+      break;
+
+    case DW_FORM_indirect:
+      get_uleb128 (u128, valp, endp);
+      // XXX Is this really correct?
+      result = __libdw_form_val_len (cu, u128, valp);
+      if (result != (size_t) -1)
+	result += valp - startp;
+      else
+        return (size_t) -1;
+      break;
+
+    default:
+      goto invalid;
+    }
+
+  if (unlikely (result > (size_t) (endp - startp)))
+    {
+    invalid:
+      __libdw_seterrno (DWARF_E_INVALID_DWARF);
+      result = (size_t) -1;
+    }
+
+  return result;
+}