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3054dd54 TT |
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" | |
82ca8957 | 28 | #include "dwarf2/read.h" |
3054dd54 TT |
29 | #include "dwarf2/abbrev.h" |
30 | #include "dwarf2/leb.h" | |
31 | #include "bfd.h" | |
32 | ||
1d33d811 TT |
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; | |
af0b2a3e TT |
39 | /* Warning: if you change this next line, you must also update the |
40 | other code in this class using the _with_hash functions. */ | |
1d33d811 TT |
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 | ||
3054dd54 TT |
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 | ||
1d33d811 TT |
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 | ||
3054dd54 TT |
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 | ||
86de1d91 | 75 | abbrev = XOBNEW (&m_abbrev_obstack, struct abbrev_info); |
3054dd54 TT |
76 | memset (abbrev, 0, sizeof (struct abbrev_info)); |
77 | ||
78 | return abbrev; | |
79 | } | |
80 | ||
81 | /* Add an abbreviation to the table. */ | |
82 | ||
83 | void | |
af0b2a3e | 84 | abbrev_table::add_abbrev (struct abbrev_info *abbrev) |
3054dd54 | 85 | { |
af0b2a3e TT |
86 | void **slot = htab_find_slot_with_hash (m_abbrevs.get (), abbrev, |
87 | abbrev->number, INSERT); | |
1d33d811 | 88 | *slot = abbrev; |
3054dd54 TT |
89 | } |
90 | ||
3054dd54 TT |
91 | /* Read in an abbrev table. */ |
92 | ||
93 | abbrev_table_up | |
86de1d91 TT |
94 | abbrev_table::read (struct objfile *objfile, |
95 | struct dwarf2_section_info *section, | |
96 | sect_offset sect_off) | |
3054dd54 TT |
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; | |
3054dd54 TT |
155 | } |
156 | ||
b3b32279 | 157 | cur_abbrev->num_attrs = cur_attrs.size (); |
3054dd54 | 158 | cur_abbrev->attrs = |
86de1d91 | 159 | XOBNEWVEC (&abbrev_table->m_abbrev_obstack, struct attr_abbrev, |
3054dd54 | 160 | cur_abbrev->num_attrs); |
af62665e TT |
161 | if (!cur_attrs.empty ()) |
162 | memcpy (cur_abbrev->attrs, cur_attrs.data (), | |
163 | cur_abbrev->num_attrs * sizeof (struct attr_abbrev)); | |
3054dd54 | 164 | |
af0b2a3e | 165 | abbrev_table->add_abbrev (cur_abbrev); |
3054dd54 TT |
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 | } |