Line data    Source code

       1             : /* Return DWARF attribute associated with a location expression op.
       2             :    Copyright (C) 2013, 2014 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 <dwarf.h>
      34             : #include <libdwP.h>
      35             : 
      36             : static Dwarf_CU *
      37             : attr_form_cu (Dwarf_Attribute *attr)
      38             : {
      39             :   /* If the attribute has block/expr form the data comes from the
      40             :      .debug_info from the same cu as the attr.  Otherwise it comes from
      41             :      the .debug_loc data section.  */
      42             :   switch (attr->form)
      43             :     {
      44             :     case DW_FORM_block1:
      45             :     case DW_FORM_block2:
      46             :     case DW_FORM_block4:
      47             :     case DW_FORM_block:
      48             :     case DW_FORM_exprloc:
      49             :       return attr->cu;
      50             :     default:
      51           6 :       return attr->cu->dbg->fake_loc_cu;
      52             :     }
      53             : }
      54             : 
      55             : int
      56          10 : dwarf_getlocation_attr (Dwarf_Attribute *attr, const Dwarf_Op *op, Dwarf_Attribute *result)
      57             : {
      58          10 :   if (attr == NULL)
      59             :     return -1;
      60             : 
      61          10 :   switch (op->atom)
      62             :     {
      63             :       case DW_OP_implicit_value:
      64           2 :         result->code = DW_AT_const_value;
      65           2 :         result->form = DW_FORM_block;
      66           2 :         result->valp = (unsigned char *) (uintptr_t) op->number2;
      67           4 :         result->cu = attr_form_cu (attr);
      68           2 :         break;
      69             : 
      70             :       case DW_OP_GNU_entry_value:
      71           6 :         result->code = DW_AT_location;
      72           6 :         result->form = DW_FORM_exprloc;
      73           6 :         result->valp = (unsigned char *) (uintptr_t) op->number2;
      74          12 :         result->cu = attr_form_cu (attr);
      75           6 :         break;
      76             : 
      77             :       case DW_OP_GNU_const_type:
      78           1 :         result->code = DW_AT_const_value;
      79           1 :         result->form = DW_FORM_block1;
      80           1 :         result->valp = (unsigned char *) (uintptr_t) op->number2;
      81           2 :         result->cu = attr_form_cu (attr);
      82           1 :         break;
      83             : 
      84             :       case DW_OP_call2:
      85             :       case DW_OP_call4:
      86             :       case DW_OP_call_ref:
      87             :         {
      88             :           Dwarf_Die die;
      89           0 :           if (INTUSE(dwarf_getlocation_die) (attr, op, &die) != 0)
      90           0 :             return -1;
      91           0 :           if (INTUSE(dwarf_attr) (&die, DW_AT_location, result) == NULL)
      92             :             {
      93           0 :               __libdw_empty_loc_attr (result);
      94           0 :               return 0;
      95             :             }
      96             :         }
      97           0 :         break;
      98             : 
      99             :       case DW_OP_GNU_implicit_pointer:
     100             :         {
     101             :           Dwarf_Die die;
     102           1 :           if (INTUSE(dwarf_getlocation_die) (attr, op, &die) != 0)
     103           0 :             return -1;
     104           1 :           if (INTUSE(dwarf_attr) (&die, DW_AT_location, result) == NULL
     105           0 :               && INTUSE(dwarf_attr) (&die, DW_AT_const_value, result) == NULL)
     106             :             {
     107           0 :               __libdw_empty_loc_attr (result);
     108           0 :               return 0;
     109             :             }
     110             :         }
     111           1 :         break;
     112             : 
     113             :       default:
     114           0 :         __libdw_seterrno (DWARF_E_INVALID_ACCESS);
     115           0 :         return -1;
     116             :     }
     117             : 
     118             :   return 0;
     119             : }