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/* Look up the DIE in a reference-form attribute.
Copyright (C) 2005-2010, 2018 Red Hat, Inc.
This file is part of elfutils.
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 <string.h>
#include "libdwP.h"
#include <dwarf.h>
Dwarf_Die *
dwarf_formref_die (Dwarf_Attribute *attr, Dwarf_Die *result)
{
if (attr == NULL)
return NULL;
struct Dwarf_CU *cu = attr->cu;
Dwarf_Off offset;
if (attr->form == DW_FORM_ref_addr || attr->form == DW_FORM_GNU_ref_alt
|| attr->form == DW_FORM_ref_sup4 || attr->form == DW_FORM_ref_sup8)
{
/* This has an absolute offset. */
uint8_t ref_size;
if (cu->version == 2 && attr->form == DW_FORM_ref_addr)
ref_size = cu->address_size;
else if (attr->form == DW_FORM_ref_sup4)
ref_size = 4;
else if (attr->form == DW_FORM_ref_sup8)
ref_size = 8;
else
ref_size = cu->offset_size;
Dwarf *dbg_ret = (attr->form == DW_FORM_GNU_ref_alt
? INTUSE(dwarf_getalt) (cu->dbg) : cu->dbg);
if (dbg_ret == NULL)
{
__libdw_seterrno (DWARF_E_NO_ALT_DEBUGLINK);
return NULL;
}
if (__libdw_read_offset (cu->dbg, dbg_ret, IDX_debug_info, attr->valp,
ref_size, &offset, IDX_debug_info, 0))
return NULL;
return INTUSE(dwarf_offdie) (dbg_ret, offset, result);
}
const unsigned char *datap;
size_t size;
if (attr->form == DW_FORM_ref_sig8)
{
/* This doesn't have an offset, but instead a value we
have to match in the type unit headers. */
uint64_t sig = read_8ubyte_unaligned (cu->dbg, attr->valp);
cu = Dwarf_Sig8_Hash_find (&cu->dbg->sig8_hash, sig);
if (cu == NULL)
{
/* Not seen before. We have to scan through the type units.
Since DWARFv5 these can (also) be found in .debug_info,
so scan that first. */
bool scan_debug_types = false;
do
{
mutex_lock (attr->cu->dbg->dwarf_lock);
cu = __libdw_intern_next_unit (attr->cu->dbg, scan_debug_types);
mutex_unlock (attr->cu->dbg->dwarf_lock);
if (cu == NULL)
{
if (scan_debug_types == false)
scan_debug_types = true;
else
{
__libdw_seterrno (INTUSE(dwarf_errno) ()
?: DWARF_E_INVALID_REFERENCE);
return NULL;
}
}
}
while (cu == NULL || cu->unit_id8 != sig);
}
int secid = cu_sec_idx (cu);
datap = cu->dbg->sectiondata[secid]->d_buf;
size = cu->dbg->sectiondata[secid]->d_size;
offset = cu->start + cu->subdie_offset;
}
else
{
/* Other forms produce an offset from the CU. */
if (unlikely (__libdw_formref (attr, &offset) != 0))
return NULL;
datap = cu->startp;
size = cu->endp - cu->startp;
}
if (unlikely (offset >= size))
{
__libdw_seterrno (DWARF_E_INVALID_DWARF);
return NULL;
}
memset (result, '\0', sizeof (Dwarf_Die));
result->addr = (char *) datap + offset;
result->cu = cu;
return result;
}
INTDEF (dwarf_formref_die)
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