Fix PR #15489 (Dynamic Library Loading Support)

CMakeLists.txt

@@ -691,6 +691,8 @@ else()
 
 endif()
 
+add_library(sample_lib SHARED ${CMAKE_CURRENT_SOURCE_DIR}/example/lib_api/mylib.cc)
+target_include_directories(sample_lib PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include/mxnet)
 set(MXNET_INSTALL_TARGETS mxnet)
 if(UNIX)
   # Create dummy file since we want an empty shared library before linking
@@ -701,9 +703,13 @@ if(UNIX)
   add_library(mxnet SHARED ${DUMMY_SOURCE})
   target_link_libraries(mxnet PRIVATE ${BEGIN_WHOLE_ARCHIVE} $<TARGET_FILE:mxnet_static> ${END_WHOLE_ARCHIVE})
   target_link_libraries(mxnet PRIVATE mxnet_static)
+  target_link_libraries(mxnet_static PUBLIC ${CMAKE_DL_LIBS})
+  target_compile_options(sample_lib PUBLIC -shared)
   set_target_properties(mxnet_static PROPERTIES OUTPUT_NAME mxnet)
 else()
   add_library(mxnet SHARED ${SOURCE})
+  target_compile_options(sample_lib PUBLIC /LD)
+  set_target_properties(sample_lib PROPERTIES PREFIX "lib")
 endif()
 
 if(USE_CUDA)

Makefile

@@ -107,7 +107,7 @@ else
 	CFLAGS += -O3 -DNDEBUG=1
 endif
 CFLAGS += -I$(TPARTYDIR)/mshadow/ -I$(TPARTYDIR)/dmlc-core/include -fPIC -I$(NNVM_PATH)/include -I$(DLPACK_PATH)/include -I$(TPARTYDIR)/tvm/include -Iinclude $(MSHADOW_CFLAGS)
-LDFLAGS = -pthread $(MSHADOW_LDFLAGS) $(DMLC_LDFLAGS)
+LDFLAGS = -pthread -ldl $(MSHADOW_LDFLAGS) $(DMLC_LDFLAGS)
 
 ifeq ($(ENABLE_TESTCOVERAGE), 1)
         CFLAGS += --coverage
@@ -454,7 +454,7 @@ endif
 .PHONY: clean all extra-packages test lint docs clean_all rcpplint rcppexport roxygen\
 	cython2 cython3 cython cyclean
 
-all: lib/libmxnet.a lib/libmxnet.so $(BIN) extra-packages
+all: lib/libmxnet.a lib/libmxnet.so $(BIN) extra-packages sample_lib
 
 SRC = $(wildcard src/*/*/*/*.cc src/*/*/*.cc src/*/*.cc src/*.cc)
 OBJ = $(patsubst %.cc, build/%.o, $(SRC))
@@ -659,6 +659,9 @@ cpplint:
 pylint:
 	python3 -m pylint --rcfile=$(ROOTDIR)/ci/other/pylintrc --ignore-patterns=".*\.so$$,.*\.dll$$,.*\.dylib$$" python/mxnet tools/caffe_converter/*.py
 
+sample_lib:
+	$(CXX) -shared -fPIC example/lib_api/mylib.cc -o libsample_lib.so -I include/mxnet
+
 doc: docs
 
 docs:

ci/jenkins/Jenkins_steps.groovy

@@ -23,8 +23,8 @@
 utils = load('ci/Jenkinsfile_utils.groovy')
 
 // mxnet libraries
-mx_lib = 'lib/libmxnet.so, lib/libmxnet.a, 3rdparty/dmlc-core/libdmlc.a, 3rdparty/tvm/nnvm/lib/libnnvm.a'
-mx_lib_cython = 'lib/libmxnet.so, lib/libmxnet.a, 3rdparty/dmlc-core/libdmlc.a, 3rdparty/tvm/nnvm/lib/libnnvm.a, python/mxnet/_cy2/*.so, python/mxnet/_cy3/*.so'
+mx_lib = 'lib/libmxnet.so, lib/libmxnet.a, libsample_lib.so, 3rdparty/dmlc-core/libdmlc.a, 3rdparty/tvm/nnvm/lib/libnnvm.a'
+mx_lib_cython = 'lib/libmxnet.so, lib/libmxnet.a, libsample_lib.so, 3rdparty/dmlc-core/libdmlc.a, 3rdparty/tvm/nnvm/lib/libnnvm.a, python/mxnet/_cy2/*.so, python/mxnet/_cy3/*.so'
 
 // Python wheels
 mx_pip = 'build/*.whl'
@@ -33,11 +33,11 @@ mx_pip = 'build/*.whl'
 mx_cmake_lib = 'build/libmxnet.so, build/libmxnet.a, build/3rdparty/dmlc-core/libdmlc.a, build/tests/mxnet_unit_tests, build/3rdparty/openmp/runtime/src/libomp.so'
 mx_cmake_lib_cython = 'build/libmxnet.so, build/libmxnet.a, build/3rdparty/dmlc-core/libdmlc.a, build/tests/mxnet_unit_tests, build/3rdparty/openmp/runtime/src/libomp.so, python/mxnet/_cy2/*.so, python/mxnet/_cy3/*.so'
 // mxnet cmake libraries, in cmake builds we do not produce a libnvvm static library by default.
-mx_cmake_lib_debug = 'build/libmxnet.so, build/libmxnet.a, build/3rdparty/dmlc-core/libdmlc.a, build/tests/mxnet_unit_tests'
+mx_cmake_lib_debug = 'build/libmxnet.so, build/libmxnet.a, build/libsample_lib.so, build/3rdparty/dmlc-core/libdmlc.a, build/tests/mxnet_unit_tests'
 mx_cmake_mkldnn_lib = 'build/libmxnet.so, build/libmxnet.a, build/3rdparty/dmlc-core/libdmlc.a, build/tests/mxnet_unit_tests, build/3rdparty/openmp/runtime/src/libomp.so, build/3rdparty/mkldnn/src/libmkldnn.so.0'
-mx_mkldnn_lib = 'lib/libmxnet.so, lib/libmxnet.a, lib/libiomp5.so, lib/libmkldnn.so.0, lib/libmklml_intel.so, 3rdparty/dmlc-core/libdmlc.a, 3rdparty/tvm/nnvm/lib/libnnvm.a'
+mx_mkldnn_lib = 'lib/libmxnet.so, lib/libmxnet.a, libsample_lib.so, lib/libiomp5.so, lib/libmkldnn.so.0, lib/libmklml_intel.so, 3rdparty/dmlc-core/libdmlc.a, 3rdparty/tvm/nnvm/lib/libnnvm.a'
 mx_tensorrt_lib = 'build/libmxnet.so, lib/libnvonnxparser_runtime.so.0, lib/libnvonnxparser.so.0, lib/libonnx_proto.so, lib/libonnx.so'
-mx_lib_cpp_examples = 'lib/libmxnet.so, lib/libmxnet.a, 3rdparty/dmlc-core/libdmlc.a, 3rdparty/tvm/nnvm/lib/libnnvm.a, 3rdparty/ps-lite/build/libps.a, deps/lib/libprotobuf-lite.a, deps/lib/libzmq.a, build/cpp-package/example/*, python/mxnet/_cy2/*.so, python/mxnet/_cy3/*.so'
+mx_lib_cpp_examples = 'lib/libmxnet.so, lib/libmxnet.a, libsample_lib.so, 3rdparty/dmlc-core/libdmlc.a, 3rdparty/tvm/nnvm/lib/libnnvm.a, 3rdparty/ps-lite/build/libps.a, deps/lib/libprotobuf-lite.a, deps/lib/libzmq.a, build/cpp-package/example/*, python/mxnet/_cy2/*.so, python/mxnet/_cy3/*.so'
 mx_lib_cpp_examples_cpu = 'build/libmxnet.so, build/cpp-package/example/*'
 
 // Python unittest for CPU

example/lib_api/Makefile

@@ -0,0 +1,31 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+all:
+	g++ -shared -fPIC mylib.cc -o mylib.so -I ../../include/mxnet
+
+test:
+	g++ -std=c++11 -O3 -o libtest libtest.cc -ldl -I ../../include/mxnet
+
+windows:
+	cl /LD mylib.cc
+
+win_test:
+	cl libtest.cc
+
+clean:
+	rm -rf mylib.so libtest

example/lib_api/libtest.cc

@@ -0,0 +1,78 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*!
+ * Copyright (c) 2015 by Contributors
+ * \file libtest.cc
+ * \brief This test checks if the library is implemented correctly
+ * and does not involve dynamic loading of library into MXNet
+ * This test is supposed to be run before test.py
+ */
+
+#if defined(_WIN32) || defined(_WIN64) || defined(__WINDOWS__)
+#include <windows.h>
+#else
+#include <dlfcn.h>
+#endif
+
+#include <iostream>
+#include "lib_api.h"
+
+#define MXNET_VERSION 10500
+
+int main(void) {
+  // Get a handle to the library.
+#if defined(_WIN32) || defined(_WIN64) || defined(__WINDOWS__)
+  HINSTANCE handle;
+  handle = LoadLibrary(TEXT("mylib.dll"));
+#else
+  void *handle;
+  handle = dlopen("mylib.so", RTLD_LAZY);
+#endif
+
+  if (!handle) {
+    std::cerr << "Unable to load library" << std::endl;
+    return 1;
+  }
+
+  // get initialize function address from the library
+  initialize_t init_lib;
+#if defined(_WIN32) || defined(_WIN64) || defined(__WINDOWS__)
+  init_lib = (initialize_t) GetProcAddress(handle, MXLIB_INITIALIZE_STR);
+#else
+  init_lib = (initialize_t) dlsym(handle, MXLIB_INITIALIZE_STR);
+#endif
+
+  if (!init_lib) {
+    std::cerr << "Unable to get function 'intialize' from library" << std::endl;
+    return 1;
+  }
+
+  // Call the function.
+  (init_lib)(MXNET_VERSION);
+
+  // Deallocate memory.
+#if defined(_WIN32) || defined(_WIN64) || defined(__WINDOWS__)
+  FreeLibrary(handle);
+#else
+  dlclose(handle);
+#endif
+
+  return 0;
+}

example/lib_api/mylib.cc

@@ -0,0 +1,37 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*!
+ * Copyright (c) 2015 by Contributors
+ * \file mylib.cc
+ * \brief Sample library file
+ */
+
+#include <iostream>
+#include "lib_api.h"
+
+int initialize(int version) {
+  if (version >= 10400) {
+    std::cout << "MXNet version " << version << " supported" << std::endl;
+    return 1;
+  } else {
+    std::cout << "MXNet version " << version << " not supported" << std::endl;
+    return 0;
+  }
+}

example/lib_api/test.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+# coding: utf-8
+# pylint: disable=arguments-differ
+
+# This test checks if dynamic loading of library into MXNet is successful
+
+import mxnet as mx
+import os
+
+if (os.name=='posix'):
+    mx.library.load('mylib.so')
+elif (os.name=='nt'):
+    mx.library.load('mylib.dll')

include/mxnet/c_api.h

@@ -226,6 +226,13 @@ MXNET_DLL const char *MXGetLastError();
 // Part 0: Global State setups
 //-------------------------------------
 
+/*!
+ * \brief Load library dynamically
+ * \param path to the library .so file
+ * \return 0 when success, -1 when failure happens.
+ */
+MXNET_DLL int MXLoadLib(const char *path);
+
 /*!
  * \brief Get list of features supported on the runtime
  * \param libFeature pointer to array of LibFeature

include/mxnet/lib_api.h

@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*!
+ * Copyright (c) 2015 by Contributors
+ * \file lib_api.h
+ * \brief APIs to interact with libraries
+ */
+#ifndef MXNET_LIB_API_H_
+#define MXNET_LIB_API_H_
+
+/*!
+ * \brief Following are the APIs implemented in the external library
+ * Each API has a #define string that is used to lookup the function in the library
+ * Followed by the function declaration
+ */
+#define MXLIB_INITIALIZE_STR "initialize"
+typedef int (*initialize_t)(int);
+
+extern "C" {
+    /*!
+     * \brief Checks if the MXNet version is supported by the library.
+     * If supported, initializes the library.
+     * \param version MXNet version number passed to library and defined as:
+     *                MXNET_VERSION = (MXNET_MAJOR*10000 + MXNET_MINOR*100 + MXNET_PATCH)
+     * \return Non-zero value on error i.e. library incompatible with passed MXNet version
+     */
+#if defined(_WIN32) || defined(_WIN64) || defined(__WINDOWS__)
+    __declspec(dllexport) int __cdecl initialize(int);
+#else
+    int initialize(int);
+#endif
+}
+#endif  // MXNET_LIB_API_H_

python/mxnet/__init__.py

@@ -26,6 +26,7 @@
 from .base import MXNetError
 from .util import is_np_shape, set_np_shape, np_shape, use_np_shape
 from . import base
+from . import library
 from . import contrib
 from . import ndarray
 from . import ndarray as nd

python/mxnet/base.py

@@ -86,7 +86,7 @@ def __repr__(self):
 
 
 class MXNetError(Exception):
-    """Error that will be throwed by all mxnet functions."""
+    """Error that will be thrown by all mxnet functions."""
     pass
 
 

python/mxnet/library.py

@@ -0,0 +1,49 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+# coding: utf-8
+"""Library management API of mxnet."""
+from __future__ import absolute_import
+import ctypes
+import os
+from .base import _LIB, check_call, MXNetError
+
+def load(path):
+    """Loads library dynamically.
+
+    Parameters
+    ---------
+    path : Path to library .so/.dll file
+
+    Returns
+    ---------
+    void
+    """
+    #check if path exists
+    if not os.path.exists(path):
+        raise MXNetError("load path %s does NOT exist" % path)
+    #check if path is an absolute path
+    if not os.path.isabs(path):
+        raise MXNetError("load path %s is not an absolute path" % path)
+    #check if path is to a library file
+    _, file_ext = os.path.splitext(path)
+    if not file_ext in ['.so', '.dll']:
+        raise MXNetError("load path %s is NOT a library file" % path)
+
+    byt_obj = path.encode('utf-8')
+    chararr = ctypes.c_char_p(byt_obj)
+    check_call(_LIB.MXLoadLib(chararr))