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_formstring.c b/libdw/dwarf_formstring.c
new file mode 100644
index 0000000..4eae0ed
--- /dev/null
+++ b/libdw/dwarf_formstring.c
@@ -0,0 +1,76 @@
+/* Return string associated with given attribute.
+   Copyright (C) 2003-2010, 2013, 2018 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"
+
+
+const char *
+dwarf_formstring (Dwarf_Attribute *attrp)
+{
+  /* Ignore earlier errors.  */
+  if (attrp == NULL)
+    return NULL;
+
+  /* We found it.  Now determine where the string is stored.  */
+  if (attrp->form == DW_FORM_string)
+    /* A simple inlined string.  */
+    return (const char *) attrp->valp;
+
+  Dwarf *dbg = attrp->cu->dbg;
+  Dwarf *dbg_ret = (attrp->form == DW_FORM_GNU_strp_alt
+		    ? INTUSE(dwarf_getalt) (dbg) : dbg);
+
+  if (unlikely (dbg_ret == NULL))
+    {
+      __libdw_seterrno (DWARF_E_NO_ALT_DEBUGLINK);
+      return NULL;
+    }
+
+
+  if (unlikely (attrp->form != DW_FORM_strp
+		   && attrp->form != DW_FORM_GNU_strp_alt)
+      || dbg_ret->sectiondata[IDX_debug_str] == NULL)
+    {
+      __libdw_seterrno (DWARF_E_NO_STRING);
+      return NULL;
+    }
+
+  uint64_t off;
+  if (__libdw_read_offset (dbg, dbg_ret, cu_sec_idx (attrp->cu), attrp->valp,
+			   attrp->cu->offset_size, &off, IDX_debug_str, 1))
+    return NULL;
+
+  return (const char *) dbg_ret->sectiondata[IDX_debug_str]->d_buf + off;
+}
+INTDEF(dwarf_formstring)