Enable building static libs (rapidsai#4673)

This PR allows building libcuml++ static libs via CMake option `-DBUILD_SHARED_LIBS=ON|OFF`.

~I was seeing a linker error due to not having `-fPIC` enabled, but I wouldn't have expected this to affect static libs. I'll investigate some more and turn it off if possible, but for now `-fPIC` is enabled.~

Authors:
  - Paul Taylor (https://github.com/trxcllnt)

Approvers:
  - Robert Maynard (https://github.com/robertmaynard)
  - Dante Gama Dessavre (https://github.com/dantegd)

URL: rapidsai#4673

cpp/CMakeLists.txt

@@ -48,6 +48,7 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 ##############################################################################
 # - User Options  ------------------------------------------------------------
 
+option(BUILD_SHARED_LIBS "Build cuML shared libraries" ON)
 option(BUILD_CUML_C_LIBRARY "Build libcuml_c shared library. Contains the cuML C API" ON)
 option(BUILD_CUML_CPP_LIBRARY "Build libcuml shared library" ON)
 option(BUILD_CUML_TESTS "Build cuML algorithm tests" ON)
@@ -205,6 +206,11 @@ endif()
 
 if(all_algo OR treeshap_algo)
   include(cmake/thirdparty/get_gputreeshap.cmake)
+  # Workaround until https://github.com/rapidsai/rapids-cmake/issues/176 is resolved
+  if(NOT BUILD_SHARED_LIBS)
+    rapids_export_package(BUILD GPUTreeShap cuml-exports)
+    rapids_export_package(INSTALL GPUTreeShap cuml-exports)
+  endif()
 endif()
 
 if(NOT SINGLEGPU)
@@ -242,7 +248,7 @@ if(BUILD_CUML_CPP_LIBRARY)
 
   # single GPU components
   # common components
-  add_library(${CUML_CPP_TARGET} SHARED
+  add_library(${CUML_CPP_TARGET}
               src/common/logger.cpp)
 
   if(all_algo OR arima_algo)
@@ -480,6 +486,7 @@ if(BUILD_CUML_CPP_LIBRARY)
                CXX_STANDARD_REQUIRED               ON
                CUDA_STANDARD                       17
                CUDA_STANDARD_REQUIRED              ON
+               POSITION_INDEPENDENT_CODE           ON
                INTERFACE_POSITION_INDEPENDENT_CODE ON
   )
 
@@ -537,7 +544,7 @@ endif()
 # - build libcuml C shared library -------------------------------------------
 
 if(BUILD_CUML_C_LIBRARY)
-  add_library(${CUML_C_TARGET} SHARED
+  add_library(${CUML_C_TARGET}
     src/common/cumlHandle.cpp
     src/common/cuml_api.cpp
     src/dbscan/dbscan_api.cpp

cpp/cmake/thirdparty/get_gputreeshap.cmake

@@ -1,5 +1,5 @@
 #=============================================================================
-# Copyright (c) 2021, NVIDIA CORPORATION.
+# Copyright (c) 2021-2022, NVIDIA CORPORATION.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -27,6 +27,43 @@ function(find_and_configure_gputreeshap)
             GIT_TAG         ${PKG_PINNED_TAG}
     )
 
+    if (GPUTreeShap_ADDED)
+        include(GNUInstallDirs)
+        install(TARGETS GPUTreeShap
+                EXPORT  gputreeshap-exports)
+
+        # clear out incorrect INTERFACE_SOURCES
+        set_target_properties(GPUTreeShap PROPERTIES INTERFACE_SOURCES "")
+        get_target_property(all_includes GPUTreeShap INTERFACE_INCLUDE_DIRECTORIES)
+        # clear out incorrect INTERFACE_INCLUDE_DIRECTORIES
+        set_target_properties(GPUTreeShap PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "")
+        # set INTERFACE_INCLUDE_DIRECTORIES appropriately
+        target_include_directories(GPUTreeShap INTERFACE
+            $<BUILD_INTERFACE:${all_includes}>
+            $<INSTALL_INTERFACE:${CMAKE_INCLUDE_DIR}>)
+
+        # generate gputreeshap-targets.cmake for install dir
+        rapids_export(INSTALL GPUTreeShap
+            EXPORT_SET gputreeshap-exports
+            GLOBAL_TARGETS GPUTreeShap
+            NAMESPACE GPUTreeShap::)
+
+        # generate gputreeshap-targets.cmake for binary dir
+        rapids_export(BUILD GPUTreeShap
+            EXPORT_SET gputreeshap-exports
+            GLOBAL_TARGETS GPUTreeShap
+            NAMESPACE GPUTreeShap::)
+
+    endif()
+
+    # do `find_dependency(GPUTreeShap) in build and install`
+    rapids_export_package(BUILD GPUTreeShap cuml-exports)
+    rapids_export_package(INSTALL GPUTreeShap cuml-exports)
+
+    # Tell cmake where it can find the generated gputreeshap-config.cmake we wrote.
+    include("${rapids-cmake-dir}/export/find_package_root.cmake")
+    rapids_export_find_package_root(BUILD GPUTreeShap [=[${CMAKE_CURRENT_LIST_DIR}]=] cuml-exports)
+
     set(GPUTreeShap_ADDED ${GPUTreeShap_ADDED} PARENT_SCOPE)
 
 endfunction()

cpp/include/cuml/manifold/common.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, NVIDIA CORPORATION.
+ * Copyright (c) 2020-2022, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,7 +30,10 @@ typedef int knn_indices_sparse_t;
  */
 template <typename value_idx, typename value_t>
 struct knn_graph {
-  knn_graph(value_idx n_rows_, int n_neighbors_) : n_rows(n_rows_), n_neighbors(n_neighbors_) {}
+  knn_graph(value_idx n_rows_, int n_neighbors_)
+    : n_rows(n_rows_), n_neighbors(n_neighbors_), knn_indices{nullptr}, knn_dists{nullptr}
+  {
+  }
 
   knn_graph(value_idx n_rows_, int n_neighbors_, value_idx* knn_indices_, value_t* knn_dists_)
     : n_rows(n_rows_), n_neighbors(n_neighbors_), knn_indices(knn_indices_), knn_dists(knn_dists_)