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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; | |
39 | return info->number; | |
40 | } | |
41 | ||
42 | /* Comparison function for abbrevs. */ | |
43 | ||
44 | static int | |
45 | eq_abbrev (const void *lhs, const void *rhs) | |
46 | { | |
47 | const struct abbrev_info *l_info = (const struct abbrev_info *) lhs; | |
48 | const struct abbrev_info *r_info = (const struct abbrev_info *) rhs; | |
49 | return l_info->number == r_info->number; | |
50 | } | |
51 | ||
3054dd54 TT |
52 | /* Abbreviation tables. |
53 | ||
54 | In DWARF version 2, the description of the debugging information is | |
55 | stored in a separate .debug_abbrev section. Before we read any | |
56 | dies from a section we read in all abbreviations and install them | |
57 | in a hash table. */ | |
58 | ||
1d33d811 TT |
59 | abbrev_table::abbrev_table (sect_offset off) |
60 | : sect_off (off), | |
61 | m_abbrevs (htab_create_alloc (20, hash_abbrev, eq_abbrev, | |
62 | nullptr, xcalloc, xfree)) | |
63 | { | |
64 | } | |
65 | ||
3054dd54 TT |
66 | /* Allocate space for a struct abbrev_info object in ABBREV_TABLE. */ |
67 | ||
68 | struct abbrev_info * | |
69 | abbrev_table::alloc_abbrev () | |
70 | { | |
71 | struct abbrev_info *abbrev; | |
72 | ||
86de1d91 | 73 | abbrev = XOBNEW (&m_abbrev_obstack, struct abbrev_info); |
3054dd54 TT |
74 | memset (abbrev, 0, sizeof (struct abbrev_info)); |
75 | ||
76 | return abbrev; | |
77 | } | |
78 | ||
79 | /* Add an abbreviation to the table. */ | |
80 | ||
81 | void | |
82 | abbrev_table::add_abbrev (unsigned int abbrev_number, | |
83 | struct abbrev_info *abbrev) | |
84 | { | |
1d33d811 TT |
85 | void **slot = htab_find_slot (m_abbrevs.get (), abbrev, INSERT); |
86 | *slot = abbrev; | |
3054dd54 TT |
87 | } |
88 | ||
89 | /* Look up an abbrev in the table. | |
90 | Returns NULL if the abbrev is not found. */ | |
91 | ||
92 | struct abbrev_info * | |
93 | abbrev_table::lookup_abbrev (unsigned int abbrev_number) | |
94 | { | |
1d33d811 TT |
95 | struct abbrev_info search; |
96 | search.number = abbrev_number; | |
3054dd54 | 97 | |
1d33d811 | 98 | return (struct abbrev_info *) htab_find (m_abbrevs.get (), &search); |
3054dd54 TT |
99 | } |
100 | ||
101 | /* Read in an abbrev table. */ | |
102 | ||
103 | abbrev_table_up | |
86de1d91 TT |
104 | abbrev_table::read (struct objfile *objfile, |
105 | struct dwarf2_section_info *section, | |
106 | sect_offset sect_off) | |
3054dd54 TT |
107 | { |
108 | bfd *abfd = section->get_bfd_owner (); | |
109 | const gdb_byte *abbrev_ptr; | |
110 | struct abbrev_info *cur_abbrev; | |
111 | unsigned int abbrev_number, bytes_read, abbrev_name; | |
112 | unsigned int abbrev_form; | |
113 | std::vector<struct attr_abbrev> cur_attrs; | |
114 | ||
115 | abbrev_table_up abbrev_table (new struct abbrev_table (sect_off)); | |
116 | ||
117 | section->read (objfile); | |
118 | abbrev_ptr = section->buffer + to_underlying (sect_off); | |
119 | abbrev_number = read_unsigned_leb128 (abfd, abbrev_ptr, &bytes_read); | |
120 | abbrev_ptr += bytes_read; | |
121 | ||
122 | /* Loop until we reach an abbrev number of 0. */ | |
123 | while (abbrev_number) | |
124 | { | |
125 | cur_attrs.clear (); | |
126 | cur_abbrev = abbrev_table->alloc_abbrev (); | |
127 | ||
128 | /* read in abbrev header */ | |
129 | cur_abbrev->number = abbrev_number; | |
130 | cur_abbrev->tag | |
131 | = (enum dwarf_tag) read_unsigned_leb128 (abfd, abbrev_ptr, &bytes_read); | |
132 | abbrev_ptr += bytes_read; | |
133 | cur_abbrev->has_children = read_1_byte (abfd, abbrev_ptr); | |
134 | abbrev_ptr += 1; | |
135 | ||
136 | /* now read in declarations */ | |
137 | for (;;) | |
138 | { | |
139 | LONGEST implicit_const; | |
140 | ||
141 | abbrev_name = read_unsigned_leb128 (abfd, abbrev_ptr, &bytes_read); | |
142 | abbrev_ptr += bytes_read; | |
143 | abbrev_form = read_unsigned_leb128 (abfd, abbrev_ptr, &bytes_read); | |
144 | abbrev_ptr += bytes_read; | |
145 | if (abbrev_form == DW_FORM_implicit_const) | |
146 | { | |
147 | implicit_const = read_signed_leb128 (abfd, abbrev_ptr, | |
148 | &bytes_read); | |
149 | abbrev_ptr += bytes_read; | |
150 | } | |
151 | else | |
152 | { | |
153 | /* Initialize it due to a false compiler warning. */ | |
154 | implicit_const = -1; | |
155 | } | |
156 | ||
157 | if (abbrev_name == 0) | |
158 | break; | |
159 | ||
160 | cur_attrs.emplace_back (); | |
161 | struct attr_abbrev &cur_attr = cur_attrs.back (); | |
162 | cur_attr.name = (enum dwarf_attribute) abbrev_name; | |
163 | cur_attr.form = (enum dwarf_form) abbrev_form; | |
164 | cur_attr.implicit_const = implicit_const; | |
3054dd54 TT |
165 | } |
166 | ||
b3b32279 | 167 | cur_abbrev->num_attrs = cur_attrs.size (); |
3054dd54 | 168 | cur_abbrev->attrs = |
86de1d91 | 169 | XOBNEWVEC (&abbrev_table->m_abbrev_obstack, struct attr_abbrev, |
3054dd54 | 170 | cur_abbrev->num_attrs); |
af62665e TT |
171 | if (!cur_attrs.empty ()) |
172 | memcpy (cur_abbrev->attrs, cur_attrs.data (), | |
173 | cur_abbrev->num_attrs * sizeof (struct attr_abbrev)); | |
3054dd54 TT |
174 | |
175 | abbrev_table->add_abbrev (abbrev_number, cur_abbrev); | |
176 | ||
177 | /* Get next abbreviation. | |
178 | Under Irix6 the abbreviations for a compilation unit are not | |
179 | always properly terminated with an abbrev number of 0. | |
180 | Exit loop if we encounter an abbreviation which we have | |
181 | already read (which means we are about to read the abbreviations | |
182 | for the next compile unit) or if the end of the abbreviation | |
183 | table is reached. */ | |
184 | if ((unsigned int) (abbrev_ptr - section->buffer) >= section->size) | |
185 | break; | |
186 | abbrev_number = read_unsigned_leb128 (abfd, abbrev_ptr, &bytes_read); | |
187 | abbrev_ptr += bytes_read; | |
188 | if (abbrev_table->lookup_abbrev (abbrev_number) != NULL) | |
189 | break; | |
190 | } | |
191 | ||
192 | return abbrev_table; | |
193 | } |