From 28379e145f5c8f06ff1f15cc6651136b64e169d4 Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Fri, 10 Apr 2020 12:16:24 -0400
Subject: [PATCH] set using C++11 w/o extensions globally. move KOKKOS only
 checks to KOKKOS.cmake

---
 cmake/CMakeLists.txt                | 11 ++---------
 cmake/Modules/Packages/KOKKOS.cmake | 16 ++++++++++++----
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index a7c3c07841..16e09af077 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -64,9 +64,10 @@ if(${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang")
   set(CMAKE_TUNE_DEFAULT "-ffast-math -march=native")
 endif()
 
-# we require C++11
+# we require C++11 without extensions
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
 
 # GNU compiler specific features for testing
 if (${CMAKE_CXX_COMPILER_ID} STREQUAL "GNU")
@@ -123,10 +124,6 @@ else()
   endif()
   add_executable(lammps ${ALL_SOURCES})
   set_target_properties(lammps PROPERTIES OUTPUT_NAME ${LAMMPS_BINARY})
-  if(Kokkos_ENABLE_CUDA)
-    # The Kokkos nvcc wrapper does not like -std=gnu++11 and wants -std=c++11
-    set_target_properties(lammps PROPERTIES CXX_EXTENSIONS OFF)
-  endif()
   install(TARGETS lammps DESTINATION ${CMAKE_INSTALL_BINDIR})
 endif()
 
@@ -261,10 +258,6 @@ if(BUILD_OMP)
     message(FATAL_ERROR "Cannot find the 'omp.h' header file required for full OpenMP support")
   endif()
   target_link_libraries(lammps PRIVATE OpenMP::OpenMP_CXX)
-else()
-  if(Kokkos_ENABLE_OPENMP)
-    message(FATAL_ERROR "Must enable BUILD_OMP with Kokkos_ENABLE_OPENMP")
-  endif()
 endif()
 
 if(PKG_MSCG OR PKG_USER-ATC OR PKG_USER-AWPMD OR PKG_USER-QUIP OR PKG_LATTE)
diff --git a/cmake/Modules/Packages/KOKKOS.cmake b/cmake/Modules/Packages/KOKKOS.cmake
index f224a565e4..9d9ef9f6cb 100644
--- a/cmake/Modules/Packages/KOKKOS.cmake
+++ b/cmake/Modules/Packages/KOKKOS.cmake
@@ -1,3 +1,15 @@
+########################################################################
+# consistency checks and Kokkos options/settings required by LAMMPS
+if(Kokkos_ENABLE_CUDA)
+  set(Kokkos_ENABLE_CUDA_LAMBDA ON)
+endif()
+# Adding OpenMP compiler flags without the checks done for
+# BUILD_OMP can result in compile failures. Enforce consistency.
+if(Kokkos_ENABLE_OPENMP AND NOT BUILD_OMP)
+  message(FATAL_ERROR "Must enable BUILD_OMP with Kokkos_ENABLE_OPENMP")
+endif()
+########################################################################
+
 option(EXTERNAL_KOKKOS "Build against external kokkos library" OFF)
 option(DOWNLOAD_KOKKOS "Download the KOKKOS library instead of using the bundled one" OFF)
 if(DOWNLOAD_KOKKOS)
@@ -31,10 +43,6 @@ elseif(EXTERNAL_KOKKOS)
 else()
   set(LAMMPS_LIB_KOKKOS_SRC_DIR ${LAMMPS_LIB_SOURCE_DIR}/kokkos)
   set(LAMMPS_LIB_KOKKOS_BIN_DIR ${LAMMPS_LIB_BINARY_DIR}/kokkos)
-  # enforce using nvcc_wrapper as compiler wrapper
-  if(Kokkos_ENABLE_CUDA)
-    set(CMAKE_CXX_COMPILER ${LAMMPS_LIB_KOKKOS_SRC_DIR}/bin/nvcc_wrapper CACHE FILEPATH "Path to nvcc wrapper for Kokkos with CUDA" FORCE)
-  endif()
   add_subdirectory(${LAMMPS_LIB_KOKKOS_SRC_DIR} ${LAMMPS_LIB_KOKKOS_BIN_DIR})
 
   set(Kokkos_INCLUDE_DIRS ${LAMMPS_LIB_KOKKOS_SRC_DIR}/core/src