libxgboost4j is now part of the CMake build (#2373)

* [jvm-packages] Added libxgboost4j to CMake build

* [jvm-packages] Wired CMake build into create_jni.sh

* User newer CMake version on Travis

* Lowered CMake version constraints

* Fixed various quirks in the new CMake build

.travis.yml

@@ -45,7 +45,10 @@ addons:
   apt:
     sources:
       - ubuntu-toolchain-r-test
+      - george-edison55-precise-backports
     packages:
+      - cmake
+      - cmake-data
       - doxygen
       - wget
       - libcurl4-openssl-dev

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required (VERSION 3.5)
+cmake_minimum_required (VERSION 3.2)
 project (xgboost)
 find_package(OpenMP)
 
@@ -91,6 +91,8 @@ else()
     set(CMAKE_SHARED_LIBRARY_PREFIX "")
 endif()
 
+set(LINK_LIBRARIES dmlccore rabit)
+
 option(PLUGIN_UPDATER_GPU "Build GPU accelerated tree construction plugin")
 
 if(PLUGIN_UPDATER_GPU)
@@ -109,16 +111,29 @@ if(PLUGIN_UPDATER_GPU)
     cuda_add_library(updater_gpu STATIC
         ${CUDA_SOURCES}
     )
+
+    set(LINK_LIBRARIES ${LINK_LIBRARIES} updater_gpu)
 endif()
 
-add_executable(xgboost ${SOURCES})
-add_library(libxgboost SHARED ${SOURCES})
-target_link_libraries(xgboost dmlccore rabit)
-target_link_libraries(libxgboost dmlccore rabit)
+add_library(objxgboost OBJECT ${SOURCES})
+set_target_properties(${objxgboost} PROPERTIES POSITION_INDEPENDENT_CODE 1)
 
+add_library(libxgboost SHARED $<TARGET_OBJECTS:objxgboost>)
+add_executable(xgboost $<TARGET_OBJECTS:objxgboost>)
+target_link_libraries(xgboost ${LINK_LIBRARIES})
+target_link_libraries(libxgboost ${LINK_LIBRARIES})
 
-if(PLUGIN_UPDATER_GPU)
-    target_link_libraries(xgboost updater_gpu)
-    target_link_libraries(libxgboost updater_gpu)
+option(JVM_BINDINGS "Build JVM bindings" OFF)
+
+if(JVM_BINDINGS)
+    find_package(JNI QUIET REQUIRED)
+
+    include_directories(${JNI_INCLUDE_DIRS} jvm-packages/xgboost4j/src/native)
+
+    add_library(libxgboost4j SHARED
+        $<TARGET_OBJECTS:objxgboost>
+        jvm-packages/xgboost4j/src/native/xgboost4j.cpp)
+    target_link_libraries(libxgboost4j
+        ${LINK_LIBRARIES}
+        ${JNI_LIBRARIES})
 endif()
-

jvm-packages/create_jni.sh

@@ -9,18 +9,21 @@ pushd `dirname $0` > /dev/null
 
 #settings according to os
 dl="so"
-dis_omp=0
+USE_OMP=ON
 
 if [ $(uname) == "Darwin" ]; then
   export JAVA_HOME=$(/usr/libexec/java_home)
   dl="dylib"
   #change this to 0 if your compiler support openmp
-  dis_omp=1
+  USE_OMP=OFF
 fi
 
 cd ..
-make jvm no_omp=${dis_omp}
-cd jvm-packages
+mkdir -p build
+cd build
+cmake .. -DJVM_BINDINGS:BOOL=ON -DUSE_OPENMP:BOOL=${USE_OMP}
+make
+cd ../jvm-packages
 echo "move native lib"
 
 libPath="xgboost4j/src/main/resources/lib"
@@ -29,7 +32,7 @@ if [ ! -d "$libPath" ]; then
 fi
 
 rm -f xgboost4j/src/main/resources/lib/libxgboost4j.${dl}
-mv lib/libxgboost4j.so xgboost4j/src/main/resources/lib/libxgboost4j.${dl}
+cp ../lib/libxgboost4j.${dl} xgboost4j/src/main/resources/lib/libxgboost4j.${dl}
 # copy python to native resources
 cp ../dmlc-core/tracker/dmlc_tracker/tracker.py xgboost4j/src/main/resources/tracker.py
 # copy test data files

jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/NativeLibLoader.java

@@ -31,7 +31,7 @@ class NativeLibLoader {
   private static final Log logger = LogFactory.getLog(NativeLibLoader.class);
 
   private static boolean initialized = false;
-  private static final String nativePath = "../lib/";
+  private static final String nativePath = "../../lib/";
   private static final String nativeResourcePath = "/lib/";
   private static final String[] libNames = new String[]{"xgboost4j"};
 

jvm-packages/xgboost4j/src/native/xgboost4j.cpp

@@ -25,7 +25,7 @@
 // set handle
 void setHandle(JNIEnv *jenv, jlongArray jhandle, void* handle) {
 #ifdef __APPLE__
-  long out = (long) handle;
+  jlong out = (long) handle;
 #else
   int64_t out = (int64_t) handle;
 #endif
@@ -76,7 +76,8 @@ XGB_EXTERN_C int XGBoost4jCallbackDataIterNext(
         batch, jenv->GetFieldID(batchClass, "featureValue", "[F"));
       XGBoostBatchCSR cbatch;
       cbatch.size = jenv->GetArrayLength(joffset) - 1;
-      cbatch.offset = jenv->GetLongArrayElements(joffset, 0);
+      cbatch.offset = reinterpret_cast<long *>(
+          jenv->GetLongArrayElements(joffset, 0));
       if (jlabel != nullptr) {
         cbatch.label = jenv->GetFloatArrayElements(jlabel, 0);
         CHECK_EQ(jenv->GetArrayLength(jlabel), static_cast<long>(cbatch.size))
@@ -103,7 +104,8 @@ XGB_EXTERN_C int XGBoost4jCallbackDataIterNext(
       CHECK_EQ((*set_function)(set_function_handle, cbatch), 0)
           << XGBGetLastError();
       // release the elements.
-      jenv->ReleaseLongArrayElements(joffset, cbatch.offset, 0);
+      jenv->ReleaseLongArrayElements(
+          joffset, reinterpret_cast<jlong *>(cbatch.offset), 0);
       jenv->DeleteLocalRef(joffset);
       if (jlabel != nullptr) {
         jenv->ReleaseFloatArrayElements(jlabel, cbatch.label, 0);