[tarantool-patches] [PATCH] Fix libgomp linking for static build

[Kirill Yukhin]

Since addition of -fopenmp to compiler also means
addition of -lgomp to the link stage, pass -fno-openmp
to the linking stage in case of static build. In that
case OMP functions are statically linked into libmisc.

Also, emit error if trying to perform static build using
clang.
---
Branch: https://github.com/tarantool/tarantool/commits/kyukhin/gh-xxxx-fix-gomp-in-static-build
Issue: n/a

 cmake/compiler.cmake | 5 ++++-
 src/CMakeLists.txt   | 7 +++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/cmake/compiler.cmake b/cmake/compiler.cmake
index b3a0702..5b323c7 100644
--- a/cmake/compiler.cmake
+++ b/cmake/compiler.cmake
@@ -33,6 +33,10 @@ if (CMAKE_COMPILER_IS_GNUCC)
                Your GCC version is ${CMAKE_CXX_COMPILER_VERSION}, please update
                        ")
        endif()
+else()
+     if (BUILD_STATIC)
+               message(FATAL_ERROR "Static build is supported for GCC only")
+     endif()
 endif()
 
 #
@@ -284,7 +288,6 @@ if (HAVE_OPENMP)
     add_compile_flags("C;CXX" "-fopenmp")
 endif()
 
-
 if (CMAKE_COMPILER_IS_CLANG OR CMAKE_COMPILER_IS_GNUCC)
     set(HAVE_BUILTIN_CTZ 1)
     set(HAVE_BUILTIN_CTZLL 1)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ebda098..aa39d8b 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -277,6 +277,13 @@ if(BUILD_STATIC)
         endif()
     endforeach(libstatic)
     string(REPLACE ";" " " EXPORT_LIST "${EXPORT_LIST}")
+
+    if (HAVE_OPENMP)
+        # Link libgomp explicitly to make it static. Avoid linking
+        # against DSO version of libgomp, which implied by -fopenmp
+        set (common_libraries ${common_libraries} "libgomp.a")
+        set(CMAKE_EXE_LINKER_FLAGS  "${CMAKE_EXE_LINKER_FLAGS} -fno-openmp")
+    endif ()
 endif()
 
 # Exports syntax is toolchain-dependent, preprocessing is necessary
-- 
2.16.2