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_siblingof.c b/libdw/dwarf_siblingof.c
new file mode 100644
index 0000000..df39c1c
--- /dev/null
+++ b/libdw/dwarf_siblingof.c
@@ -0,0 +1,143 @@
+/* Return sibling of given DIE.
+ Copyright (C) 2003-2010, 2014, 2015 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 "libdwP.h"
+#include <dwarf.h>
+#include <string.h>
+
+
+int
+dwarf_siblingof (Dwarf_Die *die, Dwarf_Die *result)
+{
+ /* Ignore previous errors. */
+ if (die == NULL)
+ return -1;
+
+ /* result is declared NN */
+
+ if (result != die)
+ result->addr = NULL;
+
+ unsigned int level = 0;
+
+ /* Copy of the current DIE. */
+ Dwarf_Die this_die = *die;
+ /* Temporary attributes we create. */
+ Dwarf_Attribute sibattr;
+ /* Copy of the CU in the request. */
+ sibattr.cu = this_die.cu;
+ /* That's the address we start looking. */
+ unsigned char *addr = this_die.addr;
+ /* End of the buffer. */
+ unsigned char *endp = sibattr.cu->endp;
+
+ /* Search for the beginning of the next die on this level. We
+ must not return the dies for children of the given die. */
+ do
+ {
+ /* Find the end of the DIE or the sibling attribute. */
+ addr = __libdw_find_attr (&this_die, DW_AT_sibling, &sibattr.code,
+ &sibattr.form);
+ if (addr != NULL && sibattr.code == DW_AT_sibling)
+ {
+ Dwarf_Off offset;
+ sibattr.valp = addr;
+ if (unlikely (__libdw_formref (&sibattr, &offset) != 0))
+ /* Something went wrong. */
+ return -1;
+
+ /* The sibling attribute should point after this DIE in the CU.
+ But not after the end of the CU. */
+ size_t size = sibattr.cu->endp - sibattr.cu->startp;
+ size_t die_off = this_die.addr - this_die.cu->startp;
+ if (unlikely (offset >= size || offset <= die_off))
+ {
+ __libdw_seterrno (DWARF_E_INVALID_DWARF);
+ return -1;
+ }
+
+ /* Compute the next address. */
+ addr = sibattr.cu->startp + offset;
+ }
+ else if (unlikely (addr == NULL)
+ || unlikely (this_die.abbrev == DWARF_END_ABBREV))
+ return -1;
+ else if (this_die.abbrev->has_children)
+ /* This abbreviation has children. */
+ ++level;
+
+
+ while (1)
+ {
+ /* Make sure we are still in range. Some producers might skip
+ the trailing NUL bytes. */
+ if (addr >= endp)
+ return 1;
+
+ if (*addr != '\0')
+ break;
+
+ if (level-- == 0)
+ {
+ if (result != die)
+ result->addr = addr;
+ /* No more sibling at all. */
+ return 1;
+ }
+
+ ++addr;
+ }
+
+ /* Initialize the 'current DIE'. */
+ this_die.addr = addr;
+ this_die.abbrev = NULL;
+ }
+ while (level > 0);
+
+ /* Maybe we reached the end of the CU. */
+ if (addr >= endp)
+ return 1;
+
+ /* Clear the entire DIE structure. This signals we have not yet
+ determined any of the information. */
+ memset (result, '\0', sizeof (Dwarf_Die));
+
+ /* We have the address. */
+ result->addr = addr;
+
+ /* Same CU as the parent. */
+ result->cu = sibattr.cu;
+
+ return 0;
+}
+INTDEF(dwarf_siblingof)