mirror of https://github.com/F-Stack/f-stack.git
100 lines
3.5 KiB
C
100 lines
3.5 KiB
C
/* SPDX-License-Identifier: BSD-3-Clause
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* Copyright(c) 2015 Neil Horman <nhorman@tuxdriver.com>.
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* All rights reserved.
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*/
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#ifndef _RTE_FUNCTION_VERSIONING_H_
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#define _RTE_FUNCTION_VERSIONING_H_
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#include <rte_common.h>
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#ifndef RTE_USE_FUNCTION_VERSIONING
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#error Use of function versioning disabled, is "use_function_versioning=true" in meson.build?
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#endif
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#ifdef RTE_BUILD_SHARED_LIB
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/*
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* Provides backwards compatibility when updating exported functions.
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* When a symol is exported from a library to provide an API, it also provides a
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* calling convention (ABI) that is embodied in its name, return type,
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* arguments, etc. On occasion that function may need to change to accommodate
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* new functionality, behavior, etc. When that occurs, it is desirable to
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* allow for backwards compatibility for a time with older binaries that are
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* dynamically linked to the dpdk. To support that, the __vsym and
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* VERSION_SYMBOL macros are created. They, in conjunction with the
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* version.map file for a given library allow for multiple versions of
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* a symbol to exist in a shared library so that older binaries need not be
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* immediately recompiled.
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*
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* Refer to the guidelines document in the docs subdirectory for details on the
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* use of these macros
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*/
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/*
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* Macro Parameters:
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* b - function base name
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* e - function version extension, to be concatenated with base name
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* n - function symbol version string to be applied
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* f - function prototype
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* p - full function symbol name
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*/
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/*
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* VERSION_SYMBOL
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* Creates a symbol version table entry binding symbol <b>@DPDK_<n> to the internal
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* function name <b><e>
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*/
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#define VERSION_SYMBOL(b, e, n) __asm__(".symver " RTE_STR(b) RTE_STR(e) ", " RTE_STR(b) "@DPDK_" RTE_STR(n))
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/*
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* VERSION_SYMBOL_EXPERIMENTAL
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* Creates a symbol version table entry binding the symbol <b>@EXPERIMENTAL to the internal
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* function name <b><e>. The macro is used when a symbol matures to become part of the stable ABI,
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* to provide an alias to experimental for some time.
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*/
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#define VERSION_SYMBOL_EXPERIMENTAL(b, e) __asm__(".symver " RTE_STR(b) RTE_STR(e) ", " RTE_STR(b) "@EXPERIMENTAL")
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/*
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* BIND_DEFAULT_SYMBOL
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* Creates a symbol version entry instructing the linker to bind references to
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* symbol <b> to the internal symbol <b><e>
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*/
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#define BIND_DEFAULT_SYMBOL(b, e, n) __asm__(".symver " RTE_STR(b) RTE_STR(e) ", " RTE_STR(b) "@@DPDK_" RTE_STR(n))
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/*
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* __vsym
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* Annotation to be used in declaration of the internal symbol <b><e> to signal
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* that it is being used as an implementation of a particular version of symbol
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* <b>.
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*/
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#define __vsym __rte_used
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/*
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* MAP_STATIC_SYMBOL
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* If a function has been bifurcated into multiple versions, none of which
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* are defined as the exported symbol name in the map file, this macro can be
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* used to alias a specific version of the symbol to its exported name. For
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* example, if you have 2 versions of a function foo_v1 and foo_v2, where the
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* former is mapped to foo@DPDK_1 and the latter is mapped to foo@DPDK_2 when
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* building a shared library, this macro can be used to map either foo_v1 or
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* foo_v2 to the symbol foo when building a static library, e.g.:
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* MAP_STATIC_SYMBOL(void foo(), foo_v2);
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*/
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#define MAP_STATIC_SYMBOL(f, p)
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#else
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/*
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* No symbol versioning in use
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*/
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#define VERSION_SYMBOL(b, e, n)
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#define VERSION_SYMBOL_EXPERIMENTAL(b, e)
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#define __vsym
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#define BIND_DEFAULT_SYMBOL(b, e, n)
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#define MAP_STATIC_SYMBOL(f, p) f __attribute__((alias(RTE_STR(p))))
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/*
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* RTE_BUILD_SHARED_LIB=n
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*/
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#endif
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#endif /* _RTE_FUNCTION_VERSIONING_H_ */
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