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/*-
* BSD LICENSE
*
* Copyright(c) 2015 Neil Horman <nhorman@tuxdriver.com>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _RTE_COMPAT_H_
#define _RTE_COMPAT_H_
#include <rte_common.h>
#ifdef RTE_BUILD_SHARED_LIB
/*
* Provides backwards compatibility when updating exported functions.
* When a symol is exported from a library to provide an API, it also provides a
* calling convention (ABI) that is embodied in its name, return type,
* arguments, etc. On occasion that function may need to change to accommodate
* new functionality, behavior, etc. When that occurs, it is desirable to
* allow for backwards compatibility for a time with older binaries that are
* dynamically linked to the dpdk. To support that, the __vsym and
* VERSION_SYMBOL macros are created. They, in conjunction with the
* <library>_version.map file for a given library allow for multiple versions of
* a symbol to exist in a shared library so that older binaries need not be
* immediately recompiled.
*
* Refer to the guidelines document in the docs subdirectory for details on the
* use of these macros
*/
/*
* Macro Parameters:
* b - function base name
* e - function version extension, to be concatenated with base name
* n - function symbol version string to be applied
* f - function prototype
* p - full function symbol name
*/
/*
* VERSION_SYMBOL
* Creates a symbol version table entry binding symbol <b>@DPDK_<n> to the internal
* function name <b>_<e>
*/
#define VERSION_SYMBOL(b, e, n) __asm__(".symver " RTE_STR(b) RTE_STR(e) ", " RTE_STR(b) "@DPDK_" RTE_STR(n))
/*
* BIND_DEFAULT_SYMBOL
* Creates a symbol version entry instructing the linker to bind references to
* symbol <b> to the internal symbol <b>_<e>
*/
#define BIND_DEFAULT_SYMBOL(b, e, n) __asm__(".symver " RTE_STR(b) RTE_STR(e) ", " RTE_STR(b) "@@DPDK_" RTE_STR(n))
#define __vsym __attribute__((used))
/*
* MAP_STATIC_SYMBOL
* If a function has been bifurcated into multiple versions, none of which
* are defined as the exported symbol name in the map file, this macro can be
* used to alias a specific version of the symbol to its exported name. For
* example, if you have 2 versions of a function foo_v1 and foo_v2, where the
* former is mapped to foo@DPDK_1 and the latter is mapped to foo@DPDK_2 when
* building a shared library, this macro can be used to map either foo_v1 or
* foo_v2 to the symbol foo when building a static library, e.g.:
* MAP_STATIC_SYMBOL(void foo(), foo_v2);
*/
#define MAP_STATIC_SYMBOL(f, p)
#else
/*
* No symbol versioning in use
*/
#define VERSION_SYMBOL(b, e, n)
#define __vsym
#define BIND_DEFAULT_SYMBOL(b, e, n)
#define MAP_STATIC_SYMBOL(f, p) f __attribute__((alias(RTE_STR(p))))
/*
* RTE_BUILD_SHARED_LIB=n
*/
#endif
#endif /* _RTE_COMPAT_H_ */
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