Line data    Source code

       1             : /* Look up the DIE in a reference-form attribute.
       2             :    Copyright (C) 2005-2010, 2018 Red Hat, Inc.
       3             :    This file is part of elfutils.
       4             : 
       5             :    This file is free software; you can redistribute it and/or modify
       6             :    it under the terms of either
       7             : 
       8             :      * the GNU Lesser General Public License as published by the Free
       9             :        Software Foundation; either version 3 of the License, or (at
      10             :        your option) any later version
      11             : 
      12             :    or
      13             : 
      14             :      * the GNU General Public License as published by the Free
      15             :        Software Foundation; either version 2 of the License, or (at
      16             :        your option) any later version
      17             : 
      18             :    or both in parallel, as here.
      19             : 
      20             :    elfutils is distributed in the hope that it will be useful, but
      21             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      22             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      23             :    General Public License for more details.
      24             : 
      25             :    You should have received copies of the GNU General Public License and
      26             :    the GNU Lesser General Public License along with this program.  If
      27             :    not, see <http://www.gnu.org/licenses/>.  */
      28             : 
      29             : #ifdef HAVE_CONFIG_H
      30             : # include <config.h>
      31             : #endif
      32             : 
      33             : #include <string.h>
      34             : #include "libdwP.h"
      35             : #include <dwarf.h>
      36             : 
      37             : 
      38             : Dwarf_Die *
      39     1364780 : dwarf_formref_die (Dwarf_Attribute *attr, Dwarf_Die *result)
      40             : {
      41     1364780 :   if (attr == NULL)
      42             :     return NULL;
      43             : 
      44     1364780 :   struct Dwarf_CU *cu = attr->cu;
      45             : 
      46             :   Dwarf_Off offset;
      47     1364780 :   if (attr->form == DW_FORM_ref_addr || attr->form == DW_FORM_GNU_ref_alt
      48     1364743 :       || attr->form == DW_FORM_ref_sup4 || attr->form == DW_FORM_ref_sup8)
      49             :     {
      50             :       /* This has an absolute offset.  */
      51             : 
      52             :       uint8_t ref_size;
      53          37 :       if (cu->version == 2 && attr->form == DW_FORM_ref_addr)
      54           0 :         ref_size = cu->address_size;
      55          37 :       else if (attr->form == DW_FORM_ref_sup4)
      56             :         ref_size = 4;
      57          37 :       else if (attr->form == DW_FORM_ref_sup8)
      58             :         ref_size = 8;
      59             :       else
      60          37 :         ref_size = cu->offset_size;
      61             : 
      62          37 :       Dwarf *dbg_ret = (attr->form == DW_FORM_GNU_ref_alt
      63          37 :                         ? INTUSE(dwarf_getalt) (cu->dbg) : cu->dbg);
      64             : 
      65          37 :       if (dbg_ret == NULL)
      66             :         {
      67           0 :           __libdw_seterrno (DWARF_E_NO_ALT_DEBUGLINK);
      68           0 :           return NULL;
      69             :         }
      70             : 
      71          37 :       if (__libdw_read_offset (cu->dbg, dbg_ret, IDX_debug_info, attr->valp,
      72             :                                ref_size, &offset, IDX_debug_info, 0))
      73             :         return NULL;
      74             : 
      75          37 :       return INTUSE(dwarf_offdie) (dbg_ret, offset, result);
      76             :     }
      77             : 
      78             :   const unsigned char *datap;
      79             :   size_t size;
      80     1364743 :   if (attr->form == DW_FORM_ref_sig8)
      81             :     {
      82             :       /* This doesn't have an offset, but instead a value we
      83             :          have to match in the type unit headers.  */
      84             : 
      85           4 :       uint64_t sig = read_8ubyte_unaligned (cu->dbg, attr->valp);
      86           4 :       cu = Dwarf_Sig8_Hash_find (&cu->dbg->sig8_hash, sig, NULL);
      87           4 :       if (cu == NULL)
      88             :         {
      89             :           /* Not seen before.  We have to scan through the type units.
      90             :              Since DWARFv5 these can (also) be found in .debug_info,
      91             :              so scan that first.  */
      92             :           bool scan_debug_types = false;
      93             :           do
      94             :             {
      95           2 :               cu = __libdw_intern_next_unit (attr->cu->dbg, scan_debug_types);
      96           2 :               if (cu == NULL)
      97             :                 {
      98           1 :                   if (scan_debug_types == false)
      99             :                     scan_debug_types = true;
     100             :                   else
     101             :                     {
     102           0 :                       __libdw_seterrno (INTUSE(dwarf_errno) ()
     103             :                                         ?: DWARF_E_INVALID_REFERENCE);
     104           0 :                       return NULL;
     105             :                     }
     106             :                 }
     107             :             }
     108           2 :           while (cu == NULL || cu->unit_id8 != sig);
     109             :         }
     110             : 
     111           4 :       int secid = cu_sec_idx (cu);
     112           4 :       datap = cu->dbg->sectiondata[secid]->d_buf;
     113           4 :       size = cu->dbg->sectiondata[secid]->d_size;
     114           4 :       offset = cu->start + cu->subdie_offset;
     115             :     }
     116             :   else
     117             :     {
     118             :       /* Other forms produce an offset from the CU.  */
     119     1364739 :       if (unlikely (__libdw_formref (attr, &offset) != 0))
     120             :         return NULL;
     121             : 
     122     1364739 :       datap = cu->startp;
     123     1364739 :       size = cu->endp - cu->startp;
     124             :     }
     125             : 
     126     1364743 :   if (unlikely (offset >= size))
     127             :     {
     128           0 :       __libdw_seterrno (DWARF_E_INVALID_DWARF);
     129           0 :       return NULL;
     130             :     }
     131             : 
     132     1364743 :   memset (result, '\0', sizeof (Dwarf_Die));
     133     1364743 :   result->addr = (char *) datap + offset;
     134     1364743 :   result->cu = cu;
     135     1364743 :   return result;
     136             : }
     137             : INTDEF (dwarf_formref_die)