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f4382c45 TT |
1 | /* Low-level DWARF 2 reading code |
2 | ||
3666a048 | 3 | Copyright (C) 1994-2021 Free Software Foundation, Inc. |
f4382c45 TT |
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/leb.h" | |
29 | ||
30 | ULONGEST | |
31 | read_unsigned_leb128 (bfd *abfd, const gdb_byte *buf, | |
32 | unsigned int *bytes_read_ptr) | |
33 | { | |
34 | ULONGEST result; | |
35 | unsigned int num_read; | |
36 | int shift; | |
37 | unsigned char byte; | |
38 | ||
39 | result = 0; | |
40 | shift = 0; | |
41 | num_read = 0; | |
42 | while (1) | |
43 | { | |
44 | byte = bfd_get_8 (abfd, buf); | |
45 | buf++; | |
46 | num_read++; | |
47 | result |= ((ULONGEST) (byte & 127) << shift); | |
48 | if ((byte & 128) == 0) | |
49 | { | |
50 | break; | |
51 | } | |
52 | shift += 7; | |
53 | } | |
54 | *bytes_read_ptr = num_read; | |
55 | return result; | |
56 | } | |
57 | ||
58 | LONGEST | |
59 | read_signed_leb128 (bfd *abfd, const gdb_byte *buf, | |
60 | unsigned int *bytes_read_ptr) | |
61 | { | |
62 | ULONGEST result; | |
63 | int shift, num_read; | |
64 | unsigned char byte; | |
65 | ||
66 | result = 0; | |
67 | shift = 0; | |
68 | num_read = 0; | |
69 | while (1) | |
70 | { | |
71 | byte = bfd_get_8 (abfd, buf); | |
72 | buf++; | |
73 | num_read++; | |
74 | result |= ((ULONGEST) (byte & 127) << shift); | |
75 | shift += 7; | |
76 | if ((byte & 128) == 0) | |
77 | { | |
78 | break; | |
79 | } | |
80 | } | |
81 | if ((shift < 8 * sizeof (result)) && (byte & 0x40)) | |
82 | result |= -(((ULONGEST) 1) << shift); | |
83 | *bytes_read_ptr = num_read; | |
84 | return result; | |
85 | } | |
4075cb26 TT |
86 | |
87 | /* See leb.h. */ | |
88 | ||
89 | LONGEST | |
90 | read_initial_length (bfd *abfd, const gdb_byte *buf, unsigned int *bytes_read, | |
91 | bool handle_nonstd) | |
92 | { | |
93 | LONGEST length = bfd_get_32 (abfd, buf); | |
94 | ||
95 | if (length == 0xffffffff) | |
96 | { | |
97 | length = bfd_get_64 (abfd, buf + 4); | |
98 | *bytes_read = 12; | |
99 | } | |
100 | else if (handle_nonstd && length == 0) | |
101 | { | |
102 | /* Handle the (non-standard) 64-bit DWARF2 format used by IRIX. */ | |
103 | length = bfd_get_64 (abfd, buf); | |
104 | *bytes_read = 8; | |
105 | } | |
106 | else | |
107 | { | |
108 | *bytes_read = 4; | |
109 | } | |
110 | ||
111 | return length; | |
112 | } | |
24aa364d TT |
113 | |
114 | /* See leb.h. */ | |
115 | ||
116 | LONGEST | |
117 | read_offset (bfd *abfd, const gdb_byte *buf, unsigned int offset_size) | |
118 | { | |
119 | LONGEST retval = 0; | |
120 | ||
121 | switch (offset_size) | |
122 | { | |
123 | case 4: | |
124 | retval = bfd_get_32 (abfd, buf); | |
125 | break; | |
126 | case 8: | |
127 | retval = bfd_get_64 (abfd, buf); | |
128 | break; | |
129 | default: | |
130 | internal_error (__FILE__, __LINE__, | |
131 | _("read_offset_1: bad switch [in module %s]"), | |
132 | bfd_get_filename (abfd)); | |
133 | } | |
134 | ||
135 | return retval; | |
136 | } |