building a tensorflow based android app with tensorflow as a repository

Question

This is like a follow up question from Build an android app using Tensorflow. I\'d like to separate the android example project from tensorflow git repo and be able to build

Answer 1

Ah, okay, I see what you're doing. Thanks for elaborating.

The problem here is a bit subtle: copts = tf_copts() calls a function in @org_tensorflow that looks like this:

def tf_copts():
  return (["-DEIGEN_AVOID_STL_ARRAY",
           "-Iexternal/gemmlowp",
           "-Wno-sign-compare",
           "-fno-exceptions"] +
          if_cuda(["-DGOOGLE_CUDA=1"]) +
          if_android_arm(["-mfpu=neon"]) +
          if_x86(["-msse4.1"]) +
          select({
              "//tensorflow:android": [
                  "-std=c++11",
                  "-DTF_LEAN_BINARY",
                  "-O2",
              ],
              "//tensorflow:darwin": [],
              "//tensorflow:windows": [
                "/DLANG_CXX11",
                "/D__VERSION__=\\\"MSVC\\\"",
                "/DPLATFORM_WINDOWS",
                "/DEIGEN_HAS_C99_MATH",
                "/DTENSORFLOW_USE_EIGEN_THREADPOOL",
              ],
              "//tensorflow:ios": ["-std=c++11"],
              "//conditions:default": ["-pthread"]}))

Basically a switch statement to use different flags on different platforms. However, because load()s are evaluated before select()s, your BUILD file suddenly "contains" references to //tensorflow.

To fix, the easiest options are to either hard-code the copts you need or redefine tf_copts in your local repository.

How to track down incorrect references in general

I was actually pretty baffled by the error you were getting, so here's a brain dump of how one usually goes about debugging this kind of thing.

The usual way to track down this kind of cross reference is 1) to examine your BUILD file (maybe the deps are just wrong) or 2) print out how Bazel actually "sees" the BUILD file. For example, if you wanted to print the evaluated build rule in this case, you could do:

$ bazel query --output=build //:libtensorflow_demo.so
# /home/kchodorow/gitroot/so41153199/BUILD:18:1
cc_binary(
  name = "libtensorflow_demo.so",
  tags = ["manual", "notap"],
  deps = ["//:demo_proto_lib_cc", "@org_tensorflow//tensorflow/contrib/android:android_tensorflow_inference_jni", "@org_tensorflow//tensorflow/core:android_tensorflow_lib", "@org_tensorflow//tensorflow/contrib/android:jni/version_script.lds"],
  srcs = ["//:jni/box_coder_jni.cc", "//:jni/imageutils_jni.cc", "//:jni/object_tracking/config.h", "//:jni/object_tracking/flow_cache.h", "//:jni/object_tracking/frame_pair.cc", "//:jni/object_tracking/frame_pair.h", "//:jni/object_tracking/geom.h", "//:jni/object_tracking/gl_utils.h", "//:jni/object_tracking/image-inl.h", "//:jni/object_tracking/image.h", "//:jni/object_tracking/image_data.h", "//:jni/object_tracking/image_neon.cc", "//:jni/object_tracking/image_utils.h", "//:jni/object_tracking/integral_image.h", "//:jni/object_tracking/jni_utils.h", "//:jni/object_tracking/keypoint.h", "//:jni/object_tracking/keypoint_detector.cc", "//:jni/object_tracking/keypoint_detector.h", "//:jni/object_tracking/log_streaming.h", "//:jni/object_tracking/object_detector.cc", "//:jni/object_tracking/object_detector.h", "//:jni/object_tracking/object_model.h", "//:jni/object_tracking/object_tracker.cc", "//:jni/object_tracking/object_tracker.h", "//:jni/object_tracking/object_tracker_jni.cc", "//:jni/object_tracking/optical_flow.cc", "//:jni/object_tracking/optical_flow.h", "//:jni/object_tracking/sprite.h", "//:jni/object_tracking/time_log.cc", "//:jni/object_tracking/time_log.h", "//:jni/object_tracking/tracked_object.cc", "//:jni/object_tracking/tracked_object.h", "//:jni/object_tracking/utils.h", "//:jni/object_tracking/utils_neon.cc", "//:jni/rgb2yuv.cc", "//:jni/rgb2yuv.h", "//:jni/yuv2rgb.cc", "//:jni/yuv2rgb.h"],
  linkopts = ["-landroid", "-ljnigraphics", "-llog", "-lm", "-z defs", "-s", "-Wl,--version-script", "@org_tensorflow//tensorflow/contrib/android:jni/version_script.lds"],
  linkstatic = True,
  linkshared = True,
)

However, this doesn't actually help you in this case, because it doesn't show the copts!

So, after running the query, I ended up "binary searching" the BUILD rule: I commented out everything but the srcs, tried building, then gradually uncommented parts until I got the error.