[dpdk-dev] [PATCH v2 1/2] eal: split compat header file

[Bruce Richardson]

The compat.h header file provided macros for two purposes:
1. it provided the macros for marking functions as rte_experimental
2. it provided the macros for doing function versioning

Although these were in the same file, #1 is something that is for use by
public header files, which #2 is for internal use only. Therefore, we can
split these into two headers, keeping #1 in rte_compat.h and #2 in a new
file rte_function_versioning.h. For "make" builds, since internal objects
pick up the headers from the "include/" folder, we need to add the new
header to the installation list, but for "meson" builds it does not need to
be installed as it's not for public use.

The rework also serves to allow the use of the function versioning macros
to files that actually need them, so the use of experimental functions does
not need including of the versioning code.

Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
---

V2: added in missing rte_compat.h file
---
 doc/api/doxy-api-index.md                     |  3 +-
 doc/guides/contributing/versioning.rst        |  4 +-
 lib/librte_distributor/rte_distributor.c      |  2 +-
 lib/librte_distributor/rte_distributor_v20.c  |  2 +-
 lib/librte_eal/common/Makefile                |  1 +
 lib/librte_eal/common/include/rte_compat.h    | 70 ----------------
 .../common/include/rte_function_versioning.h  | 79 +++++++++++++++++++
 lib/librte_lpm/rte_lpm.c                      |  1 +
 lib/librte_lpm/rte_lpm.h                      |  1 -
 lib/librte_lpm/rte_lpm6.c                     |  1 +
 lib/librte_timer/rte_timer.c                  |  2 +-
 11 files changed, 89 insertions(+), 77 deletions(-)
 create mode 100644 lib/librte_eal/common/include/rte_function_versioning.h

diff --git a/doc/api/doxy-api-index.md b/doc/api/doxy-api-index.md
index 6c2d888ee..9acf36ba1 100644
--- a/doc/api/doxy-api-index.md
+++ b/doc/api/doxy-api-index.md
@@ -171,5 +171,6 @@ The public API headers are grouped by topics:
 - **misc**:
   [EAL config]         (@ref rte_eal.h),
   [common]             (@ref rte_common.h),
-  [ABI compat]         (@ref rte_compat.h),
+  [experimental APIs]  (@ref rte_compat.h),
+  [ABI versioning]     (@ref rte_function_versioning.h),
   [version]            (@ref rte_version.h)
diff --git a/doc/guides/contributing/versioning.rst b/doc/guides/contributing/versioning.rst
index 3ab2c4346..64984c54e 100644
--- a/doc/guides/contributing/versioning.rst
+++ b/doc/guides/contributing/versioning.rst
@@ -206,7 +206,7 @@ functionality or behavior. When that occurs, it is desirable to allow for
 backward compatibility for a time with older binaries that are dynamically
 linked to the DPDK.
 
-To support backward compatibility the ``rte_compat.h``
+To support backward compatibility the ``rte_function_versioning.h``
 header file provides macros to use when updating exported functions. These
 macros are used in conjunction with the ``rte_<library>_version.map`` file for
 a given library to allow multiple versions of a symbol to exist in a shared
@@ -362,7 +362,7 @@ the function, we add this line of code
 
    VERSION_SYMBOL(rte_acl_create, _v20, 2.0);
 
-Remembering to also add the rte_compat.h header to the requisite c file where
+Remembering to also add the rte_function_versioning.h header to the requisite c file where
 these changes are being made.  The above macro instructs the linker to create a
 new symbol ``rte_acl_create at DPDK_2.0``, which matches the symbol created in older
 builds, but now points to the above newly named function.  We have now mapped
diff --git a/lib/librte_distributor/rte_distributor.c b/lib/librte_distributor/rte_distributor.c
index 21eb1fb0a..6d1e971a9 100644
--- a/lib/librte_distributor/rte_distributor.c
+++ b/lib/librte_distributor/rte_distributor.c
@@ -8,7 +8,7 @@
 #include <rte_mbuf.h>
 #include <rte_memory.h>
 #include <rte_cycles.h>
-#include <rte_compat.h>
+#include <rte_function_versioning.h>
 #include <rte_memzone.h>
 #include <rte_errno.h>
 #include <rte_string_fns.h>
diff --git a/lib/librte_distributor/rte_distributor_v20.c b/lib/librte_distributor/rte_distributor_v20.c
index cdc0969a8..64c611fa9 100644
--- a/lib/librte_distributor/rte_distributor_v20.c
+++ b/lib/librte_distributor/rte_distributor_v20.c
@@ -9,7 +9,7 @@
 #include <rte_memory.h>
 #include <rte_memzone.h>
 #include <rte_errno.h>
-#include <rte_compat.h>
+#include <rte_function_versioning.h>
 #include <rte_string_fns.h>
 #include <rte_eal_memconfig.h>
 #include <rte_pause.h>
diff --git a/lib/librte_eal/common/Makefile b/lib/librte_eal/common/Makefile
index a00d4fcad..d70f84fd7 100644
--- a/lib/librte_eal/common/Makefile
+++ b/lib/librte_eal/common/Makefile
@@ -4,6 +4,7 @@
 include $(RTE_SDK)/mk/rte.vars.mk
 
 INC := rte_branch_prediction.h rte_common.h rte_compat.h
+INC += rte_function_versioning.h
 INC += rte_debug.h rte_eal.h rte_eal_interrupts.h
 INC += rte_errno.h rte_launch.h rte_lcore.h
 INC += rte_log.h rte_memory.h rte_memzone.h
diff --git a/lib/librte_eal/common/include/rte_compat.h b/lib/librte_eal/common/include/rte_compat.h
index 92ff28faf..3eb33784b 100644
--- a/lib/librte_eal/common/include/rte_compat.h
+++ b/lib/librte_eal/common/include/rte_compat.h
@@ -5,76 +5,6 @@
 
 #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 at DPDK_1 and the latter is mapped to foo at 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
 
 #ifndef ALLOW_EXPERIMENTAL_API
 
diff --git a/lib/librte_eal/common/include/rte_function_versioning.h b/lib/librte_eal/common/include/rte_function_versioning.h
new file mode 100644
index 000000000..ce963d4b1
--- /dev/null
+++ b/lib/librte_eal/common/include/rte_function_versioning.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2015 Neil Horman <nhorman at tuxdriver.com>.
+ * All rights reserved.
+ */
+
+#ifndef _RTE_FUNCTION_VERSIONING_H_
+#define _RTE_FUNCTION_VERSIONING_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 at DPDK_1 and the latter is mapped to foo at 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_FUNCTION_VERSIONING_H_ */
diff --git a/lib/librte_lpm/rte_lpm.c b/lib/librte_lpm/rte_lpm.c
index 3a929a1b1..c96395e26 100644
--- a/lib/librte_lpm/rte_lpm.c
+++ b/lib/librte_lpm/rte_lpm.c
@@ -22,6 +22,7 @@
 #include <rte_rwlock.h>
 #include <rte_spinlock.h>
 #include <rte_tailq.h>
+#include <rte_function_versioning.h>
 
 #include "rte_lpm.h"
 
diff --git a/lib/librte_lpm/rte_lpm.h b/lib/librte_lpm/rte_lpm.h
index 906ec4483..26303e628 100644
--- a/lib/librte_lpm/rte_lpm.h
+++ b/lib/librte_lpm/rte_lpm.h
@@ -20,7 +20,6 @@
 #include <rte_memory.h>
 #include <rte_common.h>
 #include <rte_vect.h>
-#include <rte_compat.h>
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/lib/librte_lpm/rte_lpm6.c b/lib/librte_lpm/rte_lpm6.c
index 9b8aeb972..e20f82460 100644
--- a/lib/librte_lpm/rte_lpm6.c
+++ b/lib/librte_lpm/rte_lpm6.c
@@ -25,6 +25,7 @@
 #include <assert.h>
 #include <rte_jhash.h>
 #include <rte_tailq.h>
+#include <rte_function_versioning.h>
 
 #include "rte_lpm6.h"
 
diff --git a/lib/librte_timer/rte_timer.c b/lib/librte_timer/rte_timer.c
index bdcf05d06..3834c9473 100644
--- a/lib/librte_timer/rte_timer.c
+++ b/lib/librte_timer/rte_timer.c
@@ -25,8 +25,8 @@
 #include <rte_pause.h>
 #include <rte_memzone.h>
 #include <rte_malloc.h>
-#include <rte_compat.h>
 #include <rte_errno.h>
+#include <rte_function_versioning.h>
 
 #include "rte_timer.h"
 
-- 
2.21.0