From b96849918d802f750657b3dc3d17324e070993a2 Mon Sep 17 00:00:00 2001
From: Tsukasa OMOTO <tomoto@if-el.se>
Date: Sat, 26 Jan 2019 13:40:59 +0900
Subject: [PATCH] Fix build on macOS Mojave (#1923)

* Fix build on macOS Mojave

Fixed #1898

- https://iscinumpy.gitlab.io/post/omp-on-high-sierra/
- https://cliutils.gitlab.io/modern-cmake/chapters/packages/OpenMP.html
- https://github.com/Homebrew/homebrew-core/pull/20589

* update setup.py

* update docs

* fix setup.py

* update docs

* update docs

* update setup.py

* update docs
---
 CMakeLists.txt              |  4 ++--
 docs/Installation-Guide.rst | 25 +++++++++++++++++++++++++
 python-package/setup.py     | 14 ++++++++++++++
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 057302ba9..6941cbb7e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -211,8 +211,8 @@ endif(USE_MPI)
 
 if(USE_OPENMP)
     if(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
-        TARGET_LINK_LIBRARIES(lightgbm ${OpenMP_libomp_LIBRARY})
-        TARGET_LINK_LIBRARIES(_lightgbm ${OpenMP_libomp_LIBRARY})
+        TARGET_LINK_LIBRARIES(lightgbm OpenMP::OpenMP_CXX)
+        TARGET_LINK_LIBRARIES(_lightgbm OpenMP::OpenMP_CXX)
     endif()
 endif(USE_OPENMP)
 
diff --git a/docs/Installation-Guide.rst b/docs/Installation-Guide.rst
index 0ec0493b4..5fc3801d7 100644
--- a/docs/Installation-Guide.rst
+++ b/docs/Installation-Guide.rst
@@ -146,7 +146,19 @@ Only **Apple Clang** version 8.1 or higher is supported.
 
      git clone --recursive https://github.com/Microsoft/LightGBM ; cd LightGBM
      mkdir build ; cd build
+
+     # For Mojave (10.14)
+     cmake \
+       -DOpenMP_C_FLAGS="-Xpreprocessor -fopenmp -I$(brew --prefix libomp)/include" \
+       -DOpenMP_C_LIB_NAMES="omp" \
+       -DOpenMP_CXX_FLAGS="-Xpreprocessor -fopenmp -I$(brew --prefix libomp)/include" \
+       -DOpenMP_CXX_LIB_NAMES="omp" \
+       -DOpenMP_omp_LIBRARY=$(brew --prefix libomp)/lib/libomp.dylib \
+       ..
+
+     # For High Sierra or earlier (<= 10.13)
      cmake ..
+
      make -j4
 
 gcc
@@ -436,7 +448,20 @@ Only **Apple Clang** version 8.1 or higher is supported.
 
      git clone --recursive https://github.com/Microsoft/LightGBM ; cd LightGBM
      mkdir build ; cd build
+
+     # For Mojave (10.14)
+     cmake \
+       -DUSE_MPI=ON \
+       -DOpenMP_C_FLAGS="-Xpreprocessor -fopenmp -I$(brew --prefix libomp)/include" \
+       -DOpenMP_C_LIB_NAMES="omp" \
+       -DOpenMP_CXX_FLAGS="-Xpreprocessor -fopenmp -I$(brew --prefix libomp)/include" \
+       -DOpenMP_CXX_LIB_NAMES="omp" \
+       -DOpenMP_omp_LIBRARY=$(brew --prefix libomp)/lib/libomp.dylib \
+       ..
+
+     # For High Sierra or earlier (<= 10.13)
      cmake -DUSE_MPI=ON ..
+
      make -j4
 
 gcc
diff --git a/python-package/setup.py b/python-package/setup.py
index 671d9e871..fa186bfc1 100644
--- a/python-package/setup.py
+++ b/python-package/setup.py
@@ -118,8 +118,22 @@ def compile_cpp(use_mingw=False, use_gpu=False, use_mpi=False, nomp=False,
         cmake_cmd.append("-DUSE_MPI=ON")
     if nomp:
         cmake_cmd.append("-DUSE_OPENMP=OFF")
+    if system() == 'Darwin' and not nomp:
+        cc = os.environ.get('CC')
+        cxx = os.environ.get('CXX')
+        if not (cc and cc.startswith('gcc') and cxx and cxx.startswith('g++')):
+            # Apple Clang
+            # https://github.com/Homebrew/homebrew-core/pull/20589
+            cmake_cmd.extend([
+                '-DOpenMP_C_FLAGS=-Xpreprocessor -fopenmp -I/usr/local/opt/libomp/include',
+                '-DOpenMP_C_LIB_NAMES=omp',
+                '-DOpenMP_CXX_FLAGS=-Xpreprocessor -fopenmp -I/usr/local/opt/libomp/include',
+                '-DOpenMP_CXX_LIB_NAMES=omp',
+                '-DOpenMP_omp_LIBRARY=/usr/local/opt/libomp/lib/libomp.dylib'
+            ])
     if use_hdfs:
         cmake_cmd.append("-DUSE_HDFS=ON")
+
     if system() in ('Windows', 'Microsoft'):
         if use_mingw:
             if use_mpi: