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_getfuncs.c b/libdw/dwarf_getfuncs.c
new file mode 100644
index 0000000..b95f06f
--- /dev/null
+++ b/libdw/dwarf_getfuncs.c
@@ -0,0 +1,118 @@
+/* Get function information.
+   Copyright (C) 2005, 2013, 2015 Red Hat, Inc.
+   This file is part of elfutils.
+   Written by Ulrich Drepper <drepper@redhat.com>, 2005.
+
+   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"
+
+
+struct visitor_info
+{
+  /* The user callback of dwarf_getfuncs.  */
+  int (*callback) (Dwarf_Die *, void *);
+
+  /* The user arg value to dwarf_getfuncs.  */
+  void *arg;
+
+  /* Addr of the DIE offset where to (re)start the search.  Zero for all.  */
+  void *start_addr;
+
+  /* Last subprogram DIE addr seen.  */
+  void *last_addr;
+
+  /* The CU only contains C functions.  Allows pruning of most subtrees.  */
+  bool c_cu;
+};
+
+static int
+tree_visitor (unsigned int depth __attribute__ ((unused)),
+	      struct Dwarf_Die_Chain *chain, void *arg)
+{
+  struct visitor_info *const v = arg;
+  Dwarf_Die *die = &chain->die;
+  void *start_addr = v->start_addr;
+  void *die_addr = die->addr;
+
+  /* Pure C CUs can only contain defining subprogram DIEs as direct
+     children of the CU DIE or as nested function inside a normal C
+     code constructs.  */
+  int tag = INTUSE(dwarf_tag) (die);
+  if (v->c_cu
+      && tag != DW_TAG_subprogram
+      && tag != DW_TAG_lexical_block
+      && tag != DW_TAG_inlined_subroutine)
+    {
+      chain->prune = true;
+      return DWARF_CB_OK;
+    }
+
+  /* Skip all DIEs till we found the (re)start addr.  */
+  if (start_addr != NULL)
+    {
+      if (die_addr == start_addr)
+	v->start_addr = NULL;
+      return DWARF_CB_OK;
+    }
+
+  /* If this isn't a (defining) subprogram entity, skip DIE.  */
+  if (tag != DW_TAG_subprogram
+      || INTUSE(dwarf_hasattr) (die, DW_AT_declaration))
+    return DWARF_CB_OK;
+
+  v->last_addr = die_addr;
+  return (*v->callback) (die, v->arg);
+}
+
+ptrdiff_t
+dwarf_getfuncs (Dwarf_Die *cudie, int (*callback) (Dwarf_Die *, void *),
+		void *arg, ptrdiff_t offset)
+{
+  if (unlikely (cudie == NULL
+		|| INTUSE(dwarf_tag) (cudie) != DW_TAG_compile_unit))
+    return -1;
+
+  int lang = INTUSE(dwarf_srclang) (cudie);
+  bool c_cu = (lang == DW_LANG_C89
+	       || lang == DW_LANG_C
+	       || lang == DW_LANG_C99
+	       || lang == DW_LANG_C11);
+
+  struct visitor_info v = { callback, arg, (void *) offset, NULL, c_cu };
+  struct Dwarf_Die_Chain chain = { .die = CUDIE (cudie->cu),
+				   .parent = NULL };
+  int res = __libdw_visit_scopes (0, &chain, NULL, &tree_visitor, NULL, &v);
+
+  if (res == DWARF_CB_ABORT)
+    return (ptrdiff_t) v.last_addr;
+  else
+    return res;
+}