Squashed 'third_party/elfutils/' content from commit 555e15e

Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/libdw/dwarf_formref.c b/libdw/dwarf_formref.c
new file mode 100644
index 0000000..2240a25
--- /dev/null
+++ b/libdw/dwarf_formref.c
@@ -0,0 +1,110 @@
+/* Return reference offset represented by attribute.
+   Copyright (C) 2003-2010, 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 "libdwP.h"
+
+int
+internal_function
+__libdw_formref (Dwarf_Attribute *attr, Dwarf_Off *return_offset)
+{
+  const unsigned char *datap = attr->valp;
+  const unsigned char *endp = attr->cu->endp;
+
+  if (attr->valp == NULL)
+    {
+      __libdw_seterrno (DWARF_E_INVALID_REFERENCE);
+      return -1;
+    }
+
+  switch (attr->form)
+    {
+    case DW_FORM_ref1:
+      if (datap + 1 > endp)
+	{
+	invalid:
+	  __libdw_seterrno (DWARF_E_INVALID_DWARF);
+	  return -1;
+	}
+      *return_offset = *attr->valp;
+      break;
+
+    case DW_FORM_ref2:
+      if (datap + 2 > endp)
+	goto invalid;
+      *return_offset = read_2ubyte_unaligned (attr->cu->dbg, attr->valp);
+      break;
+
+    case DW_FORM_ref4:
+      if (datap + 4 > endp)
+	goto invalid;
+      *return_offset = read_4ubyte_unaligned (attr->cu->dbg, attr->valp);
+      break;
+
+    case DW_FORM_ref8:
+      if (datap + 8 > endp)
+	goto invalid;
+      *return_offset = read_8ubyte_unaligned (attr->cu->dbg, attr->valp);
+      break;
+
+    case DW_FORM_ref_udata:
+      if (datap + 1 > endp)
+	goto invalid;
+      get_uleb128 (*return_offset, datap, endp);
+      break;
+
+    case DW_FORM_ref_addr:
+    case DW_FORM_ref_sig8:
+    case DW_FORM_GNU_ref_alt:
+      /* These aren't handled by dwarf_formref, only by dwarf_formref_die.  */
+      __libdw_seterrno (DWARF_E_INVALID_REFERENCE);
+      return -1;
+
+    default:
+      __libdw_seterrno (DWARF_E_NO_REFERENCE);
+      return -1;
+    }
+
+  return 0;
+}
+
+/* This is the old public entry point.
+   It is now deprecated in favor of dwarf_formref_die.  */
+int
+dwarf_formref (Dwarf_Attribute *attr, Dwarf_Off *return_offset)
+{
+  if (attr == NULL)
+    return -1;
+
+  return __libdw_formref (attr, return_offset);
+}