gdb/dwarf2/attribute.c

   1 /* DWARF attributes
   2
   3    Copyright (C) 1994-2020 Free Software Foundation, Inc.
   4
   5    Adapted by Gary Funck (gary@intrepid.com), Intrepid Technology,
   6    Inc.  with support from Florida State University (under contract
   7    with the Ada Joint Program Office), and Silicon Graphics, Inc.
   8    Initial contribution by Brent Benson, Harris Computer Systems, Inc.,
   9    based on Fred Fish's (Cygnus Support) implementation of DWARF 1
  10    support.
  11
  12    This file is part of GDB.
  13
  14    This program is free software; you can redistribute it and/or modify
  15    it under the terms of the GNU General Public License as published by
  16    the Free Software Foundation; either version 3 of the License, or
  17    (at your option) any later version.
  18
  19    This program is distributed in the hope that it will be useful,
  20    but WITHOUT ANY WARRANTY; without even the implied warranty of
  21    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22    GNU General Public License for more details.
  23
  24    You should have received a copy of the GNU General Public License
  25    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  26
  27 #include "defs.h"
  28 #include "dwarf2/attribute.h"
  29
  30 /* See attribute.h.  */
  31
  32 CORE_ADDR
  33 attribute::value_as_address () const
  34 {
  35   CORE_ADDR addr;
  36
  37   if (form != DW_FORM_addr && form != DW_FORM_addrx
  38       && form != DW_FORM_GNU_addr_index)
  39     {
  40       /* Aside from a few clearly defined exceptions, attributes that
  41          contain an address must always be in DW_FORM_addr form.
  42          Unfortunately, some compilers happen to be violating this
  43          requirement by encoding addresses using other forms, such
  44          as DW_FORM_data4 for example.  For those broken compilers,
  45          we try to do our best, without any guarantee of success,
  46          to interpret the address correctly.  It would also be nice
  47          to generate a complaint, but that would require us to maintain
  48          a list of legitimate cases where a non-address form is allowed,
  49          as well as update callers to pass in at least the CU's DWARF
  50          version.  This is more overhead than what we're willing to
  51          expand for a pretty rare case.  */
  52       addr = DW_UNSND (this);
  53     }
  54   else
  55     addr = DW_ADDR (this);
  56
  57   return addr;
  58 }
  59
  60 /* See attribute.h.  */
  61
  62 bool
  63 attribute::form_is_block () const
  64 {
  65   return (form == DW_FORM_block1
  66           || form == DW_FORM_block2
  67           || form == DW_FORM_block4
  68           || form == DW_FORM_block
  69           || form == DW_FORM_exprloc);
  70 }
  71
  72 /* See attribute.h.  */
  73
  74 bool
  75 attribute::form_is_section_offset () const
  76 {
  77   return (form == DW_FORM_data4
  78           || form == DW_FORM_data8
  79           || form == DW_FORM_sec_offset);
  80 }
  81
  82 /* See attribute.h.  */
  83
  84 bool
  85 attribute::form_is_constant () const
  86 {
  87   switch (form)
  88     {
  89     case DW_FORM_sdata:
  90     case DW_FORM_udata:
  91     case DW_FORM_data1:
  92     case DW_FORM_data2:
  93     case DW_FORM_data4:
  94     case DW_FORM_data8:
  95     case DW_FORM_implicit_const:
  96       return true;
  97     default:
  98       return false;
  99     }
 100 }
 101
 102 /* DW_ADDR is always stored already as sect_offset; despite for the forms
 103    besides DW_FORM_ref_addr it is stored as cu_offset in the DWARF file.  */
 104
 105 bool
 106 attribute::form_is_ref () const
 107 {
 108   switch (form)
 109     {
 110     case DW_FORM_ref_addr:
 111     case DW_FORM_ref1:
 112     case DW_FORM_ref2:
 113     case DW_FORM_ref4:
 114     case DW_FORM_ref8:
 115     case DW_FORM_ref_udata:
 116     case DW_FORM_GNU_ref_alt:
 117       return true;
 118     default:
 119       return false;
 120     }
 121 }