Android: Makefile build functionality added to build.gradle to fully …

…support Android Studio builds on Windows. Resolves tensorflow#6385

Change: 149358567

tensorflow/examples/android/build.gradle

@@ -1,14 +1,50 @@
 // This file provides basic support for building the TensorFlow demo
 // in Android Studio with Gradle.
 //
-// Note that Bazel is still used to compile the native libs, and must be
-// installed at the location noted below. This build configuration merely
+// Note that Bazel is still used by default to compile the native libs,
+// and should be installed at the location noted below. This build file
 // automates the process of calling out to it and copying the compiled
 // libraries back into the appropriate directory.
+//
+// Alternatively, experimental support for Makefile builds is provided by
+// setting buildWithMake below to true. This will allow building the demo
+// on Windows machines, but note that full equivalence with the Bazel
+// build is not yet guaranteed. See comments below for caveats and tips
+// for speeding up the build, such as as enabling ccache.
+
+// Set to true to build with make.
+// NOTE: Running a make build will cause subsequent Bazel builds to *fail*
+// unless the contrib/makefile/downloads/ and gen/ dirs are deleted afterwards.
+def buildWithMake = false
 
-def bazel_location = '/usr/local/bin/bazel'
+// Controls output directory in APK and CPU type for Bazel builds.
+// NOTE: Does not affect the Makefile build target API (yet), which currently
+// assumes armeabi-v7a. If building with make, changing this will require
+// editing the Makefile as well.
 def cpuType = 'armeabi-v7a'
-def nativeDir = 'libs/' + cpuType
+
+// Output directory in the local directory for packaging into the APK.
+def nativeOutDir = 'libs/' + cpuType
+
+// Default to building with Bazel and override with make if requested.
+def nativeBuildRule = 'buildNativeBazel'
+def demoLibPath = '../../../bazel-bin/tensorflow/examples/android/libtensorflow_demo.so'
+def inferenceLibPath = '../../../bazel-bin/tensorflow/contrib/android/libtensorflow_inference.so'
+if (buildWithMake) {
+ nativeBuildRule = 'buildNativeMake'
+ demoLibPath = '../../../tensorflow/contrib/makefile/gen/lib/libtensorflow_demo.so'
+ inferenceLibPath = '../../../tensorflow/contrib/makefile/gen/lib/libtensorflow_inference.so'
+}
+
+// Defines the NDK location for Makefile builds. Does *not* affect Bazel builds.
+// Override with your absolute NDK location if this fails to get the location
+// automatically.
+def makeNdkRoot = System.getenv('NDK_ROOT')
+
+// If building with Bazel, this is the location of the bazel binary.
+// NOTE: Bazel does not yet support building for Android on Windows,
+// so in this case the Makefile build must be used as described above.
+def bazelLocation = '/usr/local/bin/bazel'
 
 project.buildDir = 'gradleBuild'
 getProject().setBuildDir('gradleBuild')
@@ -65,21 +101,36 @@ android {
  }
 }
 
-task buildNative(type:Exec) {
+task buildNativeBazel(type: Exec) {
+ workingDir '../../..'
+ commandLine bazelLocation, 'build', '-c', 'opt', \
+ 'tensorflow/examples/android:tensorflow_native_libs', \
+ '--crosstool_top=https://external:android/crosstool', \
+ '--cpu=' + cpuType, \
+ '--host_crosstool_top=@bazel_tools//tools/cpp:toolchain'
+}
+
+task buildNativeMake(type: Exec) {
+ environment "NDK_ROOT", makeNdkRoot
+ // Tip: install ccache and uncomment the following to speed up
+ // builds significantly.
+ // environment "CC_PREFIX", 'ccache'
  workingDir '../../..'
- commandLine bazel_location, 'build', '-c', 'opt', \
- 'tensorflow/examples/android:tensorflow_native_libs', \
- '--crosstool_top=https://external:android/crosstool', \
- '--cpu=' + cpuType, \
- '--host_crosstool_top=@bazel_tools//tools/cpp:toolchain'
+ commandLine 'tensorflow/contrib/makefile/build_all_android.sh', \
+ '-s', \
+ 'tensorflow/contrib/makefile/sub_makefiles/android/Makefile.in', \
+ '-t', \
+ 'libtensorflow_inference.so libtensorflow_demo.so' \
+ //, '-T' // Uncomment to skip protobuf and speed up subsequent builds.
 }
 
 task copyNativeLibs(type: Copy) {
- from('../../../bazel-bin/tensorflow/contrib/android/') { include '*.so' }
- from('../../../bazel-bin/tensorflow/examples/android/') { include '*.so' }
- into nativeDir
+ from demoLibPath
+ from inferenceLibPath
+ into nativeOutDir
  duplicatesStrategy = 'include'
- dependsOn 'buildNative'
+ dependsOn nativeBuildRule
+ fileMode 0644
 }
 
 assemble.dependsOn copyNativeLibs