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Diffstat (limited to 'REORG.TODO/include/shlib-compat.h')
| -rw-r--r-- | REORG.TODO/include/shlib-compat.h | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/REORG.TODO/include/shlib-compat.h b/REORG.TODO/include/shlib-compat.h new file mode 100644 index 0000000000..41eb362f1d --- /dev/null +++ b/REORG.TODO/include/shlib-compat.h @@ -0,0 +1,100 @@ +/* Macros for managing ABI-compatibility definitions using ELF symbol versions. + Copyright (C) 2000-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#ifndef _SHLIB_COMPAT_H +#define _SHLIB_COMPAT_H 1 + +# include <abi-versions.h> + +#ifdef SHARED + +/* The file abi-versions.h (generated by scripts/abi-versions.awk) defines + symbols like `ABI_libm_GLIBC_2_0' for each version set in the source + code for each library. For a version set that is subsumed by a later + version set, the definition gives the subsuming set, i.e. if GLIBC_2_0 + is subsumed by GLIBC_2_1, then ABI_libm_GLIBC_2_0 == ABI_libm_GLIBC_2_1. + Each version set that is to be distinctly defined in the output has an + unique positive integer value, increasing with newer versions. Thus, + evaluating two ABI_* symbols reduces to integer values that differ only + when the two version sets named are in fact two different ABIs we are + supporting. If these do not differ, then there is no need to compile in + extra code to support this version set where it has been superseded by a + newer version. The compatibility code should be conditionalized with + e.g. `#if SHLIB_COMPAT (libm, GLIBC_2_0, GLIBC_2_2)' for code introduced + in the GLIBC_2.0 version and obsoleted in the GLIBC_2.2 version. */ + +# define SHLIB_COMPAT(lib, introduced, obsoleted) \ + _SHLIB_COMPAT (lib, introduced, obsoleted) +# define _SHLIB_COMPAT(lib, introduced, obsoleted) \ + (IS_IN (lib) \ + && (!(ABI_##lib##_##obsoleted - 0) \ + || ((ABI_##lib##_##introduced - 0) < (ABI_##lib##_##obsoleted - 0)))) + +/* That header also defines symbols like `VERSION_libm_GLIBC_2_1' to + the version set name to use for e.g. symbols first introduced into + libm in the GLIBC_2.1 version. Definitions of symbols with explicit + versions should look like: + versioned_symbol (libm, new_foo, foo, GLIBC_2_1); + This will define the symbol `foo' with the appropriate default version, + i.e. either GLIBC_2.1 or the "earliest version" specified in + shlib-versions if that is newer. */ + +# define versioned_symbol(lib, local, symbol, version) \ + versioned_symbol_1 (lib, local, symbol, version) +# define versioned_symbol_1(lib, local, symbol, version) \ + versioned_symbol_2 (local, symbol, VERSION_##lib##_##version) +# define versioned_symbol_2(local, symbol, name) \ + default_symbol_version (local, symbol, name) + +# define compat_symbol(lib, local, symbol, version) \ + compat_symbol_reference (lib, local, symbol, version) + +#else + +/* Not compiling ELF shared libraries at all, so never any old versions. */ +# define SHLIB_COMPAT(lib, introduced, obsoleted) 0 + +/* No versions to worry about, just make this the global definition. */ +# define versioned_symbol(lib, local, symbol, version) \ + weak_alias (local, symbol) + +/* This should not appear outside `#if SHLIB_COMPAT (...)'. */ +# define compat_symbol(lib, local, symbol, version) ... + +#endif + +/* Use compat_symbol_reference for a reference to a specific version + of a symbol. Use compat_symbol to define such a symbol. */ +#define compat_symbol_reference(lib, local, symbol, version) \ + compat_symbol_reference_1 (lib, local, symbol, version) +#define compat_symbol_reference_1(lib, local, symbol, version) \ + compat_symbol_reference_2 (local, symbol, VERSION_##lib##_##version) +#define compat_symbol_reference_2(local, symbol, name) \ + symbol_version_reference (local, symbol, name) + +# ifdef LINK_OBSOLETE_RPC +/* Export the symbol for both static and dynamic linking. */ +# define libc_sunrpc_symbol(name, aliasname, version) \ + strong_alias (name, aliasname) +# else +/* Export the symbol only for shared-library compatibility. */ +# define libc_sunrpc_symbol(name, aliasname, version) \ + compat_symbol (libc, name, aliasname, version); +# endif + +#endif /* shlib-compat.h */ |