| 1 | /* DWARF 2 abbreviations |
| 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/read.h" |
| 29 | #include "dwarf2/abbrev.h" |
| 30 | #include "dwarf2/leb.h" |
| 31 | #include "bfd.h" |
| 32 | |
| 33 | /* Hash function for an abbrev. */ |
| 34 | |
| 35 | static hashval_t |
| 36 | hash_abbrev (const void *item) |
| 37 | { |
| 38 | const struct abbrev_info *info = (const struct abbrev_info *) item; |
| 39 | /* Warning: if you change this next line, you must also update the |
| 40 | other code in this class using the _with_hash functions. */ |
| 41 | return info->number; |
| 42 | } |
| 43 | |
| 44 | /* Comparison function for abbrevs. */ |
| 45 | |
| 46 | static int |
| 47 | eq_abbrev (const void *lhs, const void *rhs) |
| 48 | { |
| 49 | const struct abbrev_info *l_info = (const struct abbrev_info *) lhs; |
| 50 | const struct abbrev_info *r_info = (const struct abbrev_info *) rhs; |
| 51 | return l_info->number == r_info->number; |
| 52 | } |
| 53 | |
| 54 | /* Abbreviation tables. |
| 55 | |
| 56 | In DWARF version 2, the description of the debugging information is |
| 57 | stored in a separate .debug_abbrev section. Before we read any |
| 58 | dies from a section we read in all abbreviations and install them |
| 59 | in a hash table. */ |
| 60 | |
| 61 | abbrev_table::abbrev_table (sect_offset off) |
| 62 | : sect_off (off), |
| 63 | m_abbrevs (htab_create_alloc (20, hash_abbrev, eq_abbrev, |
| 64 | nullptr, xcalloc, xfree)) |
| 65 | { |
| 66 | } |
| 67 | |
| 68 | /* Allocate space for a struct abbrev_info object in ABBREV_TABLE. */ |
| 69 | |
| 70 | struct abbrev_info * |
| 71 | abbrev_table::alloc_abbrev () |
| 72 | { |
| 73 | struct abbrev_info *abbrev; |
| 74 | |
| 75 | abbrev = XOBNEW (&m_abbrev_obstack, struct abbrev_info); |
| 76 | memset (abbrev, 0, sizeof (struct abbrev_info)); |
| 77 | |
| 78 | return abbrev; |
| 79 | } |
| 80 | |
| 81 | /* Add an abbreviation to the table. */ |
| 82 | |
| 83 | void |
| 84 | abbrev_table::add_abbrev (struct abbrev_info *abbrev) |
| 85 | { |
| 86 | void **slot = htab_find_slot_with_hash (m_abbrevs.get (), abbrev, |
| 87 | abbrev->number, INSERT); |
| 88 | *slot = abbrev; |
| 89 | } |
| 90 | |
| 91 | /* Read in an abbrev table. */ |
| 92 | |
| 93 | abbrev_table_up |
| 94 | abbrev_table::read (struct objfile *objfile, |
| 95 | struct dwarf2_section_info *section, |
| 96 | sect_offset sect_off) |
| 97 | { |
| 98 | bfd *abfd = section->get_bfd_owner (); |
| 99 | const gdb_byte *abbrev_ptr; |
| 100 | struct abbrev_info *cur_abbrev; |
| 101 | unsigned int abbrev_number, bytes_read, abbrev_name; |
| 102 | unsigned int abbrev_form; |
| 103 | std::vector<struct attr_abbrev> cur_attrs; |
| 104 | |
| 105 | abbrev_table_up abbrev_table (new struct abbrev_table (sect_off)); |
| 106 | |
| 107 | section->read (objfile); |
| 108 | abbrev_ptr = section->buffer + to_underlying (sect_off); |
| 109 | abbrev_number = read_unsigned_leb128 (abfd, abbrev_ptr, &bytes_read); |
| 110 | abbrev_ptr += bytes_read; |
| 111 | |
| 112 | /* Loop until we reach an abbrev number of 0. */ |
| 113 | while (abbrev_number) |
| 114 | { |
| 115 | cur_attrs.clear (); |
| 116 | cur_abbrev = abbrev_table->alloc_abbrev (); |
| 117 | |
| 118 | /* read in abbrev header */ |
| 119 | cur_abbrev->number = abbrev_number; |
| 120 | cur_abbrev->tag |
| 121 | = (enum dwarf_tag) read_unsigned_leb128 (abfd, abbrev_ptr, &bytes_read); |
| 122 | abbrev_ptr += bytes_read; |
| 123 | cur_abbrev->has_children = read_1_byte (abfd, abbrev_ptr); |
| 124 | abbrev_ptr += 1; |
| 125 | |
| 126 | /* now read in declarations */ |
| 127 | for (;;) |
| 128 | { |
| 129 | LONGEST implicit_const; |
| 130 | |
| 131 | abbrev_name = read_unsigned_leb128 (abfd, abbrev_ptr, &bytes_read); |
| 132 | abbrev_ptr += bytes_read; |
| 133 | abbrev_form = read_unsigned_leb128 (abfd, abbrev_ptr, &bytes_read); |
| 134 | abbrev_ptr += bytes_read; |
| 135 | if (abbrev_form == DW_FORM_implicit_const) |
| 136 | { |
| 137 | implicit_const = read_signed_leb128 (abfd, abbrev_ptr, |
| 138 | &bytes_read); |
| 139 | abbrev_ptr += bytes_read; |
| 140 | } |
| 141 | else |
| 142 | { |
| 143 | /* Initialize it due to a false compiler warning. */ |
| 144 | implicit_const = -1; |
| 145 | } |
| 146 | |
| 147 | if (abbrev_name == 0) |
| 148 | break; |
| 149 | |
| 150 | cur_attrs.emplace_back (); |
| 151 | struct attr_abbrev &cur_attr = cur_attrs.back (); |
| 152 | cur_attr.name = (enum dwarf_attribute) abbrev_name; |
| 153 | cur_attr.form = (enum dwarf_form) abbrev_form; |
| 154 | cur_attr.implicit_const = implicit_const; |
| 155 | } |
| 156 | |
| 157 | cur_abbrev->num_attrs = cur_attrs.size (); |
| 158 | cur_abbrev->attrs = |
| 159 | XOBNEWVEC (&abbrev_table->m_abbrev_obstack, struct attr_abbrev, |
| 160 | cur_abbrev->num_attrs); |
| 161 | if (!cur_attrs.empty ()) |
| 162 | memcpy (cur_abbrev->attrs, cur_attrs.data (), |
| 163 | cur_abbrev->num_attrs * sizeof (struct attr_abbrev)); |
| 164 | |
| 165 | abbrev_table->add_abbrev (cur_abbrev); |
| 166 | |
| 167 | /* Get next abbreviation. |
| 168 | Under Irix6 the abbreviations for a compilation unit are not |
| 169 | always properly terminated with an abbrev number of 0. |
| 170 | Exit loop if we encounter an abbreviation which we have |
| 171 | already read (which means we are about to read the abbreviations |
| 172 | for the next compile unit) or if the end of the abbreviation |
| 173 | table is reached. */ |
| 174 | if ((unsigned int) (abbrev_ptr - section->buffer) >= section->size) |
| 175 | break; |
| 176 | abbrev_number = read_unsigned_leb128 (abfd, abbrev_ptr, &bytes_read); |
| 177 | abbrev_ptr += bytes_read; |
| 178 | if (abbrev_table->lookup_abbrev (abbrev_number) != NULL) |
| 179 | break; |
| 180 | } |
| 181 | |
| 182 | return abbrev_table; |
| 183 | } |