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361742ed | 1 | /* Macros for managing ABI-compatibility definitions using ELF symbol versions. |
0269750c | 2 | Copyright (C) 2000, 2002, 2006, 2012 Free Software Foundation, Inc. |
361742ed RM |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
361742ed RM |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 13 | Lesser General Public License for more details. |
361742ed | 14 | |
41bdb6e2 | 15 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
361742ed RM |
18 | |
19 | #ifndef _SHLIB_COMPAT_H | |
20 | #define _SHLIB_COMPAT_H 1 | |
21 | ||
0269750c | 22 | #if defined DO_VERSIONING |
9aae89ce RM |
23 | /* Since there is just one set of .d files generated, we need to |
24 | include this unconditionally to have the dependency noticed properly. */ | |
25 | #include <abi-versions.h> /* header generated by abi-versions.awk */ | |
9ee80c52 | 26 | #endif |
361742ed | 27 | |
0269750c | 28 | #if defined SHARED && defined DO_VERSIONING |
361742ed RM |
29 | |
30 | /* The file abi-versions.h (generated by scripts/abi-versions.awk) defines | |
cb832354 RM |
31 | symbols like `ABI_libm_GLIBC_2_0' for each version set in the source |
32 | code for each library. For a version set that is subsumed by a later | |
33 | version set, the definition gives the subsuming set, i.e. if GLIBC_2_0 | |
34 | is subsumed by GLIBC_2_1, then ABI_libm_GLIBC_2_0 == ABI_libm_GLIBC_2_1. | |
35 | Each version set that is to be distinctly defined in the output has an | |
36 | unique positive integer value, increasing with newer versions. Thus, | |
37 | evaluating two ABI_* symbols reduces to integer values that differ only | |
38 | when the two version sets named are in fact two different ABIs we are | |
39 | supporting. If these do not differ, then there is no need to compile in | |
40 | extra code to support this version set where it has been superseded by a | |
41 | newer version. The compatibility code should be conditionalized with | |
42 | e.g. `#if SHLIB_COMPAT (libm, GLIBC_2_0, GLIBC_2_2)' for code introduced | |
43 | in the GLIBC_2.0 version and obsoleted in the GLIBC_2.2 version. */ | |
44 | ||
ce460d04 | 45 | # define SHLIB_COMPAT(lib, introduced, obsoleted) \ |
11bf311e UD |
46 | _SHLIB_COMPAT (lib, introduced, obsoleted) |
47 | # define _SHLIB_COMPAT(lib, introduced, obsoleted) \ | |
ce460d04 RM |
48 | ((IS_IN_##lib - 0) \ |
49 | && (!(ABI_##lib##_##obsoleted - 0) \ | |
50 | || ((ABI_##lib##_##introduced - 0) < (ABI_##lib##_##obsoleted - 0)))) | |
51 | ||
52 | # ifndef NOT_IN_libc | |
53 | # define IS_IN_libc 1 | |
54 | # endif | |
361742ed RM |
55 | |
56 | /* That header also defines symbols like `VERSION_libm_GLIBC_2_1' to | |
57 | the version set name to use for e.g. symbols first introduced into | |
58 | libm in the GLIBC_2.1 version. Definitions of symbols with explicit | |
59 | versions should look like: | |
60 | versioned_symbol (libm, new_foo, foo, GLIBC_2_1); | |
61 | This will define the symbol `foo' with the appropriate default version, | |
62 | i.e. either GLIBC_2.1 or the "earliest version" specified in | |
63 | shlib-versions if that is newer. */ | |
64 | ||
cb162e13 | 65 | # define versioned_symbol(lib, local, symbol, version) \ |
11bf311e UD |
66 | versioned_symbol_1 (lib, local, symbol, version) |
67 | # define versioned_symbol_1(lib, local, symbol, version) \ | |
68 | versioned_symbol_2 (local, symbol, VERSION_##lib##_##version) | |
69 | # define versioned_symbol_2(local, symbol, name) \ | |
cb162e13 | 70 | default_symbol_version (local, symbol, name) |
361742ed | 71 | |
2ae13e20 | 72 | # define compat_symbol(lib, local, symbol, version) \ |
11bf311e UD |
73 | compat_symbol_1 (lib, local, symbol, version) |
74 | # define compat_symbol_1(lib, local, symbol, version) \ | |
75 | compat_symbol_2 (local, symbol, VERSION_##lib##_##version) | |
76 | # define compat_symbol_2(local, symbol, name) \ | |
2ae13e20 RM |
77 | symbol_version (local, symbol, name) |
78 | ||
361742ed RM |
79 | #else |
80 | ||
81 | /* Not compiling ELF shared libraries at all, so never any old versions. */ | |
cb832354 | 82 | # define SHLIB_COMPAT(lib, introduced, obsoleted) 0 |
361742ed RM |
83 | |
84 | /* No versions to worry about, just make this the global definition. */ | |
cb162e13 | 85 | # define versioned_symbol(lib, local, symbol, version) \ |
361742ed RM |
86 | weak_alias (local, symbol) |
87 | ||
2ae13e20 RM |
88 | /* This should not appear outside `#if SHLIB_COMPAT (...)'. */ |
89 | # define compat_symbol(lib, local, symbol, version) ... | |
90 | ||
361742ed RM |
91 | #endif |
92 | ||
93 | ||
94 | #endif /* shlib-compat.h */ |