From 0bda8e719b607cfb1d03dabff0575e656b8df6fe Mon Sep 17 00:00:00 2001
From: Mark Abraham <mark.j.abraham@gmail.com>
Date: Mon, 27 Jun 2016 19:18:12 +0200
Subject: [PATCH] Work around glibc 2.23 with CUDA

Note: Cherry-pick of e2cd2e2e from the 2016 branch.

Fixes #2022

Change-Id: Id9881efb3f26af341b9c89b4bd1f983a2149c9e4
---
 cmake/TestGlibcVersion.cpp      | 11 +++++++++++
 cmake/gmxManageNvccConfig.cmake | 19 +++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 cmake/TestGlibcVersion.cpp

diff --git a/cmake/TestGlibcVersion.cpp b/cmake/TestGlibcVersion.cpp
new file mode 100644
index 0000000000..ae63eb4cf1
--- /dev/null
+++ b/cmake/TestGlibcVersion.cpp
@@ -0,0 +1,11 @@
+#include <features.h>
+
+int main()
+{
+    // This compiles if the C++ compiler is using glibc with version 2.23+
+#if (__GLIBC__ > 2) || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 23)
+    return 0;
+#else
+#error A glibc version prior to 2.23 was found
+#endif
+}
diff --git a/cmake/gmxManageNvccConfig.cmake b/cmake/gmxManageNvccConfig.cmake
index 028a83ff1c..3fb17418da 100644
--- a/cmake/gmxManageNvccConfig.cmake
+++ b/cmake/gmxManageNvccConfig.cmake
@@ -99,6 +99,23 @@ if (NOT DEFINED CUDA_HOST_COMPILER AND NOT MSVC)
     endif()
 endif()
 
+# glibc 2.23 changed string.h in a way that breaks CUDA compilation in
+# many projects, but which has a trivial workaround. It would be nicer
+# to compile with nvcc and see that the workaround is necessary and
+# effective, but it is unclear how to do that. Also, grepping in the
+# glibc source shows that _FORCE_INLINES is only used in this string.h
+# feature and performance of memcpy variants is unimportant for CUDA
+# code in GROMACS. So this workaround is good enough to keep problems
+# away from users installing GROMACS. See Redmine 1942.
+function(work_around_glibc_2_23)
+    try_compile(IS_GLIBC_2_23_OR_HIGHER ${CMAKE_BINARY_DIR} ${CMAKE_SOURCE_DIR}/cmake/TestGlibcVersion.cpp)
+    if(IS_GLIBC_2_23_OR_HIGHER)
+        message(STATUS "Adding work-around for issue compiling CUDA code with glibc 2.23 string.h")
+        list(APPEND CUDA_HOST_COMPILER_OPTIONS "-D_FORCE_INLINES")
+        set(CUDA_HOST_COMPILER_OPTIONS ${CUDA_HOST_COMPILER_OPTIONS} PARENT_SCOPE)
+    endif()
+endfunction()
+
 # set up host compiler and its options
 if(CUDA_HOST_COMPILER_CHANGED)
     # FindCUDA in CMake 2.8.10 sets the host compiler internally
@@ -134,6 +151,8 @@ if(CUDA_HOST_COMPILER_CHANGED)
         list(APPEND CUDA_HOST_COMPILER_OPTIONS "-D__STRICT_ANSI__")
     endif()
 
+    work_around_glibc_2_23()
+
     set(CUDA_HOST_COMPILER_OPTIONS "${CUDA_HOST_COMPILER_OPTIONS}"
         CACHE STRING "Options for nvcc host compiler (do not edit!).")
 
-- 
2.11.4.GIT