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 #include "dwarf2/stringify.h"
  30 #include "complaints.h"
  31
  32 /* See attribute.h.  */
  33
  34 CORE_ADDR
  35 attribute::as_address () const
  36 {
  37   CORE_ADDR addr;
  38
  39   if (form != DW_FORM_addr && form != DW_FORM_addrx
  40       && form != DW_FORM_GNU_addr_index)
  41     {
  42       /* Aside from a few clearly defined exceptions, attributes that
  43          contain an address must always be in DW_FORM_addr form.
  44          Unfortunately, some compilers happen to be violating this
  45          requirement by encoding addresses using other forms, such
  46          as DW_FORM_data4 for example.  For those broken compilers,
  47          we try to do our best, without any guarantee of success,
  48          to interpret the address correctly.  It would also be nice
  49          to generate a complaint, but that would require us to maintain
  50          a list of legitimate cases where a non-address form is allowed,
  51          as well as update callers to pass in at least the CU's DWARF
  52          version.  This is more overhead than what we're willing to
  53          expand for a pretty rare case.  */
  54       addr = u.unsnd;
  55     }
  56   else
  57     addr = u.addr;
  58
  59   return addr;
  60 }
  61
  62 /* See attribute.h.  */
  63
  64 bool
  65 attribute::form_is_string () const
  66 {
  67   return (form == DW_FORM_strp || form == DW_FORM_line_strp
  68           || form == DW_FORM_string
  69           || form == DW_FORM_strx
  70           || form == DW_FORM_strx1
  71           || form == DW_FORM_strx2
  72           || form == DW_FORM_strx3
  73           || form == DW_FORM_strx4
  74           || form == DW_FORM_GNU_str_index
  75           || form == DW_FORM_GNU_strp_alt);
  76 }
  77
  78 /* See attribute.h.  */
  79
  80 const char *
  81 attribute::as_string () const
  82 {
  83   if (form_is_string ())
  84     return u.str;
  85   return nullptr;
  86 }
  87
  88 /* See attribute.h.  */
  89
  90 bool
  91 attribute::form_is_block () const
  92 {
  93   return (form == DW_FORM_block1
  94           || form == DW_FORM_block2
  95           || form == DW_FORM_block4
  96           || form == DW_FORM_block
  97           || form == DW_FORM_exprloc
  98           || form == DW_FORM_data16);
  99 }
 100
 101 /* See attribute.h.  */
 102
 103 bool
 104 attribute::form_is_section_offset () const
 105 {
 106   return (form == DW_FORM_data4
 107           || form == DW_FORM_data8
 108           || form == DW_FORM_sec_offset
 109           || form == DW_FORM_loclistx);
 110 }
 111
 112 /* See attribute.h.  */
 113
 114 bool
 115 attribute::form_is_constant () const
 116 {
 117   switch (form)
 118     {
 119     case DW_FORM_sdata:
 120     case DW_FORM_udata:
 121     case DW_FORM_data1:
 122     case DW_FORM_data2:
 123     case DW_FORM_data4:
 124     case DW_FORM_data8:
 125     case DW_FORM_implicit_const:
 126       return true;
 127     default:
 128       return false;
 129     }
 130 }
 131
 132 /* See attribute.h.  */
 133
 134 void
 135 attribute::get_ref_die_offset_complaint () const
 136 {
 137   complaint (_("unsupported die ref attribute form: '%s'"),
 138              dwarf_form_name (form));
 139 }
 140
 141 /* See attribute.h.  */
 142
 143 LONGEST
 144 attribute::constant_value (int default_value) const
 145 {
 146   if (form == DW_FORM_sdata || form == DW_FORM_implicit_const)
 147     return u.snd;
 148   else if (form == DW_FORM_udata
 149            || form == DW_FORM_data1
 150            || form == DW_FORM_data2
 151            || form == DW_FORM_data4
 152            || form == DW_FORM_data8)
 153     return u.unsnd;
 154   else
 155     {
 156       /* For DW_FORM_data16 see attribute::form_is_constant.  */
 157       complaint (_("Attribute value is not a constant (%s)"),
 158                  dwarf_form_name (form));
 159       return default_value;
 160     }
 161 }
 162
 163 /* See attribute.h.  */
 164
 165 bool
 166 attribute::form_is_unsigned () const
 167 {
 168   return (form == DW_FORM_ref_addr
 169           || form == DW_FORM_GNU_ref_alt
 170           || form == DW_FORM_data2
 171           || form == DW_FORM_data4
 172           || form == DW_FORM_data8
 173           || form == DW_FORM_sec_offset
 174           || form == DW_FORM_data1
 175           || form == DW_FORM_flag
 176           || form == DW_FORM_flag_present
 177           || form == DW_FORM_udata
 178           || form == DW_FORM_rnglistx
 179           || form == DW_FORM_ref1
 180           || form == DW_FORM_ref2
 181           || form == DW_FORM_ref4
 182           || form == DW_FORM_ref8
 183           || form == DW_FORM_ref_udata);
 184 }
 185
 186 /* See attribute.h.  */
 187
 188 bool
 189 attribute::form_requires_reprocessing () const
 190 {
 191   return (form == DW_FORM_strx1
 192           || form == DW_FORM_strx2
 193           || form == DW_FORM_strx3
 194           || form == DW_FORM_strx4
 195           || form == DW_FORM_GNU_str_index
 196           || form == DW_FORM_addrx
 197           || form == DW_FORM_GNU_addr_index);
 198 }