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::value_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 = DW_UNSND (this); 55 } 56 else 57 addr = DW_ADDR (this); 58 59 return addr; 60 } 61 62 /* See attribute.h. */ 63 64 const char * 65 attribute::value_as_string () const 66 { 67 if (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 return DW_STRING (this); 77 return nullptr; 78 } 79 80 /* See attribute.h. */ 81 82 bool 83 attribute::form_is_block () const 84 { 85 return (form == DW_FORM_block1 86 || form == DW_FORM_block2 87 || form == DW_FORM_block4 88 || form == DW_FORM_block 89 || form == DW_FORM_exprloc); 90 } 91 92 /* See attribute.h. */ 93 94 bool 95 attribute::form_is_section_offset () const 96 { 97 return (form == DW_FORM_data4 98 || form == DW_FORM_data8 99 || form == DW_FORM_sec_offset 100 || form == DW_FORM_loclistx); 101 } 102 103 /* See attribute.h. */ 104 105 bool 106 attribute::form_is_constant () const 107 { 108 switch (form) 109 { 110 case DW_FORM_sdata: 111 case DW_FORM_udata: 112 case DW_FORM_data1: 113 case DW_FORM_data2: 114 case DW_FORM_data4: 115 case DW_FORM_data8: 116 case DW_FORM_implicit_const: 117 return true; 118 default: 119 return false; 120 } 121 } 122 123 /* See attribute.h. */ 124 125 void 126 attribute::get_ref_die_offset_complaint () const 127 { 128 complaint (_("unsupported die ref attribute form: '%s'"), 129 dwarf_form_name (form)); 130 } 131 132 /* See attribute.h. */ 133 134 LONGEST 135 attribute::constant_value (int default_value) const 136 { 137 if (form == DW_FORM_sdata || form == DW_FORM_implicit_const) 138 return DW_SND (this); 139 else if (form == DW_FORM_udata 140 || form == DW_FORM_data1 141 || form == DW_FORM_data2 142 || form == DW_FORM_data4 143 || form == DW_FORM_data8) 144 return DW_UNSND (this); 145 else 146 { 147 /* For DW_FORM_data16 see attribute::form_is_constant. */ 148 complaint (_("Attribute value is not a constant (%s)"), 149 dwarf_form_name (form)); 150 return default_value; 151 } 152 } 153