From f90e26cb4bffbef8c0b00b8774887963232c8b0a Mon Sep 17 00:00:00 2001
From: Boris Ranto <branto@redhat.com>
Date: Tue, 3 Aug 2021 20:44:47 +0200
Subject: [PATCH] librados/librados_c: Use symver attribute if available

Fixes: https://tracker.ceph.com/issues/40060
Signed-off-by: Boris Ranto <branto@redhat.com>
---
 cmake/modules/CephChecks.cmake |  7 +++++++
 src/include/config-h.in.cmake  |  3 +++
 src/librados/librados_c.cc     | 10 ++++++++++
 3 files changed, 20 insertions(+)

diff --git a/cmake/modules/CephChecks.cmake b/cmake/modules/CephChecks.cmake
index 634fa02a8ecfb..4317e4f4eec1d 100644
--- a/cmake/modules/CephChecks.cmake
+++ b/cmake/modules/CephChecks.cmake
@@ -148,6 +148,13 @@ endif(NOT CMAKE_CROSSCOMPILING)
 set(version_script_source "v1 { }; v2 { } v1;")
 file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/version_script.txt "${version_script_source}")
 cmake_push_check_state(RESET)
+set(CMAKE_REQUIRED_FLAGS "-Werror=attribute -Wl,--version-script=${CMAKE_CURRENT_BINARY_DIR}/version_script.txt")
+check_c_source_compiles("
+__attribute__((__symver__ (\"func@v1\"))) void func_v1() {};
+__attribute__((__symver__ (\"func@v2\"))) void func_v2() {};
+
+int main() {}"
+  HAVE_ATTR_SYMVER)
 set(CMAKE_REQUIRED_FLAGS -Wl,--version-script=${CMAKE_CURRENT_BINARY_DIR}/version_script.txt)
 check_c_source_compiles("
 void func_v1() {}
diff --git a/src/include/config-h.in.cmake b/src/include/config-h.in.cmake
index 167e8be41f816..01681c494612c 100644
--- a/src/include/config-h.in.cmake
+++ b/src/include/config-h.in.cmake
@@ -271,6 +271,9 @@
 /* Define if the C compiler supports __PRETTY_FUNCTION__ */
 #cmakedefine HAVE_PRETTY_FUNC
 
+/* Define if the C compiler supports __attribute__((__symver__ (".."))) */
+#cmakedefine HAVE_ATTR_SYMVER
+
 /* Define if the C compiler supports __asm__(".symver ..") */
 #cmakedefine HAVE_ASM_SYMVER
 
diff --git a/src/librados/librados_c.cc b/src/librados/librados_c.cc
index 7bb912628240f..dd1723dd5eb33 100644
--- a/src/librados/librados_c.cc
+++ b/src/librados/librados_c.cc
@@ -44,15 +44,25 @@
 #endif
 
 #ifdef HAVE_ASM_SYMVER
+#ifdef HAVE_ATTR_SYMVER
 #define LIBRADOS_C_API_BASE(fn)               \
   extern __typeof (_##fn##_base) _##fn##_base __attribute__((__symver__ (#fn "@")))
 #define LIBRADOS_C_API_BASE_DEFAULT(fn)       \
   extern __typeof (_##fn) _##fn __attribute__((__symver__ (#fn "@@")))
 #define LIBRADOS_C_API_DEFAULT(fn, ver)       \
   extern __typeof (_##fn) _##fn __attribute__((__symver__ (#fn "@@LIBRADOS_" #ver)))
+#else
+#define LIBRADOS_C_API_BASE(fn)               \
+  asm(".symver _" #fn "_base, " #fn "@")
+#define LIBRADOS_C_API_BASE_DEFAULT(fn)       \
+  asm(".symver _" #fn ", " #fn "@@")
+#define LIBRADOS_C_API_DEFAULT(fn, ver)       \
+  asm(".symver _" #fn ", " #fn "@@LIBRADOS_" #ver)
+#endif
 
 #define LIBRADOS_C_API_BASE_F(fn) _ ## fn ## _base
 #define LIBRADOS_C_API_DEFAULT_F(fn) _ ## fn
+
 #else
 #define LIBRADOS_C_API_BASE(fn)
 #define LIBRADOS_C_API_BASE_DEFAULT(fn)
-- 
2.39.5