Macros to better support the Linux shared library symbol version mechanism.
These versions of the macros have a way to build with symbol versions
disabled for static linking, and also a way to disable all of the
compat symbols (eg to support uclibc).
The new cmake flag -DNO_COMPAT_SYMS=1 will cause the shared libraries
to be built only with default (@@) symbols.
Signed-off-by: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>
---
CMakeLists.txt | 9 ++++
buildlib/config.h.in | 4 ++
buildlib/rdma_functions.cmake | 3 ++
util/CMakeLists.txt | 1 +
util/symver.h | 100 ++++++++++++++++++++++++++++++++++++++++++
5 files changed, 117 insertions(+)
create mode 100644 util/symver.h
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2324cf49aff5a8..81ec949d6e9f4a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,6 +24,10 @@
# Use the historical search path for providers, in the standard system library.
# -DKERNEL_DIR='.../linux' (default '')
# If set use the kernel UAPI headers from this kernel source tree.
+# -DNO_COMPAT_SYMS=1 (default disabled)
+# Do not generate backwards compatibility symbols in the shared
+# libraries. This may is necessary if using a dynmic linker that does
+# not support symbol versions, such as uclibc.
cmake_minimum_required(VERSION 2.8.11 FATAL_ERROR)
project(rdma-core C)
@@ -267,6 +271,11 @@ RDMA_AddOptLDFlag(CMAKE_SHARED_LINKER_FLAGS SUPPORTS_NO_UNDEFINED "-Wl,--no-unde
# Verify that GNU --version-script and asm(".symver") works
find_package(LDSymVer REQUIRED)
+if (NO_COMPAT_SYMS)
+ set(HAVE_LIMITED_SYMBOL_VERSIONS 1)
+else()
+ set(HAVE_FULL_SYMBOL_VERSIONS 1)
+endif()
#-------------------------
# Find libraries
diff --git a/buildlib/config.h.in b/buildlib/config.h.in
index b879bc9034d328..81982d89db3d5a 100644
--- a/buildlib/config.h.in
+++ b/buildlib/config.h.in
@@ -33,6 +33,10 @@
#cmakedefine HAVE_WORKING_IF_H 1
+// Operating mode for symbol versions
+#cmakedefine HAVE_FULL_SYMBOL_VERSIONS 1
+#cmakedefine HAVE_LIMITED_SYMBOL_VERSIONS 1
+
@SIZEOF_LONG_CODE@
#if @NL_KIND@ == 3
diff --git a/buildlib/rdma_functions.cmake b/buildlib/rdma_functions.cmake
index ba1bf9c5c5f0c5..d69afd3deb7531 100644
--- a/buildlib/rdma_functions.cmake
+++ b/buildlib/rdma_functions.cmake
@@ -87,6 +87,7 @@ function(rdma_library DEST VERSION_SCRIPT SOVERSION VERSION)
set_target_properties(${DEST}-static PROPERTIES
OUTPUT_NAME ${DEST}
ARCHIVE_OUTPUT_DIRECTORY "${BUILD_LIB}")
+ target_compile_definitions(${DEST}-static PRIVATE _STATIC_LIBRARY_BUILD_=1)
install(TARGETS ${DEST}-static DESTINATION "${CMAKE_INSTALL_LIBDIR}")
list(APPEND RDMA_STATIC_LIBS ${DEST} ${DEST}-static)
@@ -122,6 +123,7 @@ function(rdma_shared_provider DEST VERSION_SCRIPT SOVERSION VERSION)
add_library(${DEST}-static STATIC ${ARGN})
set_target_properties(${DEST}-static PROPERTIES OUTPUT_NAME ${DEST})
set_target_properties(${DEST}-static PROPERTIES ARCHIVE_OUTPUT_DIRECTORY "${BUILD_LIB}")
+ target_compile_definitions(${DEST}-static PRIVATE _STATIC_LIBRARY_BUILD_=1)
install(TARGETS ${DEST}-static DESTINATION "${CMAKE_INSTALL_LIBDIR}")
list(APPEND RDMA_STATIC_LIBS ${DEST} ${DEST}-static)
@@ -172,6 +174,7 @@ function(rdma_provider DEST)
if (ENABLE_STATIC)
add_library(${DEST} STATIC ${ARGN})
set_target_properties(${DEST} PROPERTIES ARCHIVE_OUTPUT_DIRECTORY "${BUILD_LIB}")
+ target_compile_definitions(${DEST} PRIVATE _STATIC_LIBRARY_BUILD_=1)
install(TARGETS ${DEST} DESTINATION "${CMAKE_INSTALL_LIBDIR}")
list(APPEND RDMA_STATIC_LIBS "${DEST}-rdmav${IBVERBS_PABI_VERSION}" ${DEST})
diff --git a/util/CMakeLists.txt b/util/CMakeLists.txt
index 581bf6822ec39f..2ba6a7c79e222c 100644
--- a/util/CMakeLists.txt
+++ b/util/CMakeLists.txt
@@ -1,5 +1,6 @@
publish_internal_headers(util
compiler.h
+ symver.h
util.h
)
diff --git a/util/symver.h b/util/symver.h
new file mode 100644
index 00000000000000..e739b5a11cc2ac
--- /dev/null
+++ b/util/symver.h
@@ -0,0 +1,100 @@
+/* GPLv2 or OpenIB.org BSD (MIT) See COPYING file
+
+ These definitions help using the ELF symbol version feature, and must be
+ used in conjunction with the library's map file.
+ */
+
+#ifndef __UTIL_SYMVER_H
+#define __UTIL_SYMVER_H
+
+#include <config.h>
+#include <ccan/str.h>
+
+/*
+ These macros should only be used if the library is defining compatibility
+ symbols, eg:
+
+ 213: 000000000000a650 315 FUNC GLOBAL DEFAULT 13 ibv_get_device_list@IBVERBS_1.0
+ 214: 000000000000b020 304 FUNC GLOBAL DEFAULT 13 ibv_get_device_list@@IBVERBS_1.1
+
+ Symbols which have only a single implementation should use a normal extern
+ function and be placed in the correct stanza in the linker map file.
+
+ Follow this pattern to use this feature:
+ public.h:
+ struct ibv_device **ibv_get_device_list(int *num_devices);
+ foo.c:
+ // Implement the latest version
+ LATEST_SYMVER_FUNC(ibv_get_device_list, 1_1, "IBVERBS_1.1",
+ struct ibv_device **,
+ int *num_devices)
+ {
+ ...
+ }
+
+ // Implement the compat version
+ COMPAT_SYMVER_FUNC(ibv_get_device_list, 1_0, "IBVERBS_1.0",
+ struct ibv_device_1_0 **,
+ int *num_devices)
+ {
+ ...
+ }
+
+ As well as matching information in the map file.
+
+ These macros deal with the various uglyness in gcc surrounding symbol
+ versions
+
+ - The internal name __public_1_x is synthesized by the macro
+ - A prototype for the internal name is created by the macro
+ - If statically linking the latest symbol expands into a normal function
+ definition
+ - If statically linking the compat symbols expand into unused static
+ functions are are discarded by the compiler.
+ - The prototype of the latest symbol is checked against the public
+ prototype (only when compiling statically)
+
+ The extra prototypes are included only to avoid -Wmissing-prototypes
+ warnings. See also Documentation/versioning.md
+*/
+
+#define _MAKE_SYMVER(_local_sym, _public_sym, _ver_str) \
+ asm(".symver " #_local_sym "," #_public_sym "@" _ver_str)
+#define _MAKE_SYMVER_FUNC(_public_sym, _uniq, _ver_str, _ret, ...) \
+ _ret __##_public_sym##_##_uniq(__VA_ARGS__); \
+ _MAKE_SYMVER(__##_public_sym##_##_uniq, _public_sym, _ver_str); \
+ _ret __##_public_sym##_##_uniq(__VA_ARGS__)
+
+#if defined(HAVE_FULL_SYMBOL_VERSIONS) && !defined(_STATIC_LIBRARY_BUILD_)
+
+ // Produce all symbol versions for dynamic linking
+
+# define COMPAT_SYMVER_FUNC(_public_sym, _uniq, _ver_str, _ret, ...) \
+ _MAKE_SYMVER_FUNC(_public_sym, _uniq, _ver_str, _ret, __VA_ARGS__)
+# define LATEST_SYMVER_FUNC(_public_sym, _uniq, _ver_str, _ret, ...) \
+ _MAKE_SYMVER_FUNC(_public_sym, _uniq, "@" _ver_str, _ret, __VA_ARGS__)
+
+#elif defined(HAVE_LIMITED_SYMBOL_VERSIONS) && !defined(_STATIC_LIBRARY_BUILD_)
+
+ /* Produce only implemenations for the latest symbol and tag it with the
+ * correct symbol versions. This supports dynamic linkers that do not
+ * understand symbol versions
+ */
+# define COMPAT_SYMVER_FUNC(_public_sym, _uniq, _ver_str, _ret, ...) \
+ static inline _ret __##_public_sym##_##_uniq(__VA_ARGS__)
+# define LATEST_SYMVER_FUNC(_public_sym, _uniq, _ver_str, _ret, ...) \
+ _MAKE_SYMVER_FUNC(_public_sym, _uniq, "@" _ver_str, _ret, __VA_ARGS__)
+
+#else
+
+ // Static linking, or linker does not support symbol versions
+# define COMPAT_SYMVER_FUNC(_public_sym, _uniq, _ver_str, _ret, ...) \
+ static inline _ret __##_public_sym##_##_uniq(__VA_ARGS__)
+# define LATEST_SYMVER_FUNC(_public_sym, _uniq, _ver_str, _ret, ...) \
+ static _ret __##_public_sym##_##_uniq(__VA_ARGS__) \
+ __attribute__((alias(stringify(_public_sym)))); \
+ extern _ret _public_sym(__VA_ARGS__)
+
+#endif
+
+#endif
--
2.7.4
--
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