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 #ifndef GDB_DWARF2_ATTRIBUTE_H 28 #define GDB_DWARF2_ATTRIBUTE_H 29 30 #include "dwarf2.h" 31 #include "gdbtypes.h" 32 33 /* Blocks are a bunch of untyped bytes. */ 34 struct dwarf_block 35 { 36 size_t size; 37 38 /* Valid only if SIZE is not zero. */ 39 const gdb_byte *data; 40 }; 41 42 /* Attributes have a name and a value. */ 43 struct attribute 44 { 45 /* Read the given attribute value as an address, taking the 46 attribute's form into account. */ 47 CORE_ADDR value_as_address () const; 48 49 /* If the attribute has a string form, return the string value; 50 otherwise return NULL. */ 51 const char *value_as_string () const; 52 53 /* Return non-zero if ATTR's value is a section offset --- classes 54 lineptr, loclistptr, macptr or rangelistptr --- or zero, otherwise. 55 You may use DW_UNSND (attr) to retrieve such offsets. 56 57 Section 7.5.4, "Attribute Encodings", explains that no attribute 58 may have a value that belongs to more than one of these classes; it 59 would be ambiguous if we did, because we use the same forms for all 60 of them. */ 61 62 bool form_is_section_offset () const; 63 64 /* Return non-zero if ATTR's value falls in the 'constant' class, or 65 zero otherwise. When this function returns true, you can apply 66 the constant_value method to it. 67 68 However, note that for some attributes you must check 69 attr_form_is_section_offset before using this test. DW_FORM_data4 70 and DW_FORM_data8 are members of both the constant class, and of 71 the classes that contain offsets into other debug sections 72 (lineptr, loclistptr, macptr or rangelistptr). The DWARF spec says 73 that, if an attribute's can be either a constant or one of the 74 section offset classes, DW_FORM_data4 and DW_FORM_data8 should be 75 taken as section offsets, not constants. 76 77 DW_FORM_data16 is not considered as constant_value cannot handle 78 that. */ 79 80 bool form_is_constant () const; 81 82 /* DW_ADDR is always stored already as sect_offset; despite for the forms 83 besides DW_FORM_ref_addr it is stored as cu_offset in the DWARF file. */ 84 85 bool form_is_ref () const 86 { 87 return (form == DW_FORM_ref_addr 88 || form == DW_FORM_ref1 89 || form == DW_FORM_ref2 90 || form == DW_FORM_ref4 91 || form == DW_FORM_ref8 92 || form == DW_FORM_ref_udata 93 || form == DW_FORM_GNU_ref_alt); 94 } 95 96 /* Check if the attribute's form is a DW_FORM_block* 97 if so return true else false. */ 98 99 bool form_is_block () const; 100 101 /* Return DIE offset of this attribute. Return 0 with complaint if 102 the attribute is not of the required kind. */ 103 104 sect_offset get_ref_die_offset () const 105 { 106 if (form_is_ref ()) 107 return (sect_offset) u.unsnd; 108 get_ref_die_offset_complaint (); 109 return {}; 110 } 111 112 /* Return the constant value held by this attribute. Return 113 DEFAULT_VALUE if the value held by the attribute is not 114 constant. */ 115 116 LONGEST constant_value (int default_value) const; 117 118 119 ENUM_BITFIELD(dwarf_attribute) name : 16; 120 ENUM_BITFIELD(dwarf_form) form : 15; 121 122 /* Has DW_STRING already been updated by dwarf2_canonicalize_name? This 123 field should be in u.str (existing only for DW_STRING) but it is kept 124 here for better struct attribute alignment. */ 125 unsigned int string_is_canonical : 1; 126 127 union 128 { 129 const char *str; 130 struct dwarf_block *blk; 131 ULONGEST unsnd; 132 LONGEST snd; 133 CORE_ADDR addr; 134 ULONGEST signature; 135 } 136 u; 137 138 private: 139 140 /* Used by get_ref_die_offset to issue a complaint. */ 141 142 void get_ref_die_offset_complaint () const; 143 }; 144 145 /* Get at parts of an attribute structure. */ 146 147 #define DW_STRING(attr) ((attr)->u.str) 148 #define DW_STRING_IS_CANONICAL(attr) ((attr)->string_is_canonical) 149 #define DW_UNSND(attr) ((attr)->u.unsnd) 150 #define DW_BLOCK(attr) ((attr)->u.blk) 151 #define DW_SND(attr) ((attr)->u.snd) 152 #define DW_ADDR(attr) ((attr)->u.addr) 153 #define DW_SIGNATURE(attr) ((attr)->u.signature) 154 155 #endif /* GDB_DWARF2_ATTRIBUTE_H */ 156