TensorFlow core debug; missing debug symbols

Question

I'm trying to learn TensorFlow's internals by stepping from its CIFAR-10 model training's python code into its core C++ code. Using Eclipse+PyDev for step by step debugging of the python code works great, but I can't find how to step into the C++ code of the TensorFlow core. I tried using Eclipse CDT to build the C++ code in a separate project, and attach the debugger to the python process running cifar10_train.py as described here, but the symbols are never loaded and (obviously) deferred breakpoints are never hit.

Background and setup:

I'm running on Ubuntu 14.04 LTS, installed the TensorFlow code from sources as described here and my CDT project uses a Makefile containing

bazel build -c dbg //tensorflow/cc:tutorials_example_trainer.

Answer 1

TensorFlow loads a library called _pywrap_tensorflow.so that includes its C API (as defined in tensorflow/tensorflow/core/client/tensor_c_api.cc ).

In my case the library loaded during runtime was located in
~/tensorflow/local/lib/python2.7/site-packages/tensorflow/python/_pywrap_tensorflow.so
but the library that was built from the local source code was located in ~/.cache/bazel/_bazel_<username>/dbb3c677efbf9967e464a5c6a1e69337/tensorflow/bazel-out/local_linux-dbg/bin/tensorflow/python/_pywrap_tensorflow.so.

Copying the locally built library over the loaded library, and attaching to the python process as defined in the question solved the problem.