correct compliation of cuml c library (#3908)

Resolves two issues found when trying to build `cuml` locally. 

The first was that the `CUML_C_TARGET` had `FAISS` in the public link requirements, which doesn't look needed. This caused CMake configuration errors when trying to generate the `cuml-config.cmake` file. Solution was to move `FAISS` to be a private dependency ( brought in via `CUML_CPP_TARGET` )

The second was that the `CUML_C_TARGET`  tests need to make sure the `C` library is enabled. CUML doesn't enable this language by default as the `CUML_C_TARGET` builds using the `C++` compiler and exposes a `C` API via `extern C` blocks. 
I didn't go with a blanket enable `C` language as each language enabled, as that would increase the default requirements to build CUML when testing is disabled.

Authors:
  - Robert Maynard (https://github.com/robertmaynard)

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

URL: #3908

cpp/CMakeLists.txt

@@ -375,6 +375,7 @@ if(BUILD_CUML_C_LIBRARY)
   target_link_libraries(${CUML_C_TARGET}
     PUBLIC
       ${CUML_CPP_TARGET}
+    PRIVATE
       FAISS::FAISS
   )
 
@@ -448,6 +449,13 @@ rapids_export(BUILD cuml
     FINAL_CODE_BLOCK code_string
     )
 
+##############################################################################
+# - build benchmark executable -----------------------------------------------
+
+if(BUILD_CUML_BENCH OR BUILD_CUML_PRIMS_BENCH)
+  add_subdirectory(bench)
+endif(BUILD_CUML_BENCH)
+
 ##############################################################################
 # - doxygen targets ----------------------------------------------------------
 

cpp/bench/CMakeLists.txt

@@ -81,6 +81,7 @@ if(BUILD_CUML_PRIMS_BENCH)
 
   target_link_libraries(${PRIMS_BENCH_TARGET}
     PUBLIC
+      cuml
       CUDA::cublas
       benchmark::benchmark
       raft::raft
@@ -89,5 +90,6 @@ if(BUILD_CUML_PRIMS_BENCH)
   target_include_directories(${PRIMS_BENCH_TARGET}
     PRIVATE
       $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../src_prims>
+      $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
   )
 endif(BUILD_CUML_PRIMS_BENCH)

cpp/bench/prims/add.cu

@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
+#include <common/ml_benchmark.hpp>
 #include <raft/linalg/add.cuh>
 #include <raft/mr/device/allocator.hpp>
-#include "../common/ml_benchmark.hpp"
 
 namespace MLCommon {
 namespace Bench {

cpp/bench/prims/distance_common.cuh

@@ -15,9 +15,9 @@
  */
 
 #include <raft/cudart_utils.h>
+#include <common/ml_benchmark.hpp>
 #include <raft/distance/distance.cuh>
 #include <raft/mr/device/allocator.hpp>
-#include "../common/ml_benchmark.hpp"
 
 namespace MLCommon {
 namespace Bench {

cpp/bench/prims/fused_l2_nn.cu

@@ -15,12 +15,12 @@
  */
 
 #include <raft/cudart_utils.h>
+#include <common/ml_benchmark.hpp>
 #include <limits>
 #include <raft/distance/fused_l2_nn.cuh>
 #include <raft/linalg/norm.cuh>
 #include <raft/mr/device/allocator.hpp>
 #include <raft/random/rng.cuh>
-#include "../common/ml_benchmark.hpp"
 
 namespace MLCommon {
 namespace Bench {

cpp/bench/prims/gram_matrix.cu

@@ -15,6 +15,7 @@
  */
 
 #include <cuml/matrix/kernelparams.h>
+#include <common/ml_benchmark.hpp>
 #include <matrix/grammatrix.cuh>
 #include <matrix/kernelfactory.cuh>
 #include <memory>
@@ -23,7 +24,6 @@
 #include <sstream>
 #include <string>
 #include <vector>
-#include "../common/ml_benchmark.hpp"
 
 namespace MLCommon {
 namespace Bench {

cpp/bench/prims/make_blobs.cu

@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
+#include <common/ml_benchmark.hpp>
 #include <raft/mr/device/allocator.hpp>
 #include <random/make_blobs.cuh>
-#include "../common/ml_benchmark.hpp"
 
 namespace MLCommon {
 namespace Bench {

cpp/bench/prims/map_then_reduce.cu

@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
+#include <common/ml_benchmark.hpp>
 #include <raft/linalg/map_then_reduce.cuh>
 #include <raft/mr/device/allocator.hpp>
-#include "../common/ml_benchmark.hpp"
 
 namespace MLCommon {
 namespace Bench {

cpp/bench/prims/matrix_vector_op.cu

@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
+#include <common/ml_benchmark.hpp>
 #include <raft/linalg/matrix_vector_op.cuh>
 #include <raft/mr/device/allocator.hpp>
-#include "../common/ml_benchmark.hpp"
 
 namespace MLCommon {
 namespace Bench {

cpp/bench/prims/permute.cu

@@ -15,10 +15,10 @@
  */
 
 #include <raft/cudart_utils.h>
+#include <common/ml_benchmark.hpp>
 #include <raft/mr/device/allocator.hpp>
 #include <raft/random/rng.cuh>
 #include <random/permute.cuh>
-#include "../common/ml_benchmark.hpp"
 
 namespace MLCommon {
 namespace Bench {

cpp/bench/prims/reduce.cu

@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
+#include <common/ml_benchmark.hpp>
 #include <raft/linalg/reduce.cuh>
 #include <raft/mr/device/allocator.hpp>
-#include "../common/ml_benchmark.hpp"
 
 namespace MLCommon {
 namespace Bench {

cpp/bench/prims/rng.cu

@@ -15,9 +15,9 @@
  */
 
 #include <raft/cudart_utils.h>
+#include <common/ml_benchmark.hpp>
 #include <raft/mr/device/allocator.hpp>
 #include <raft/random/rng.cuh>
-#include "../common/ml_benchmark.hpp"
 
 namespace MLCommon {
 namespace Bench {

cpp/cmake/thirdparty/get_faiss.cmake

@@ -39,7 +39,7 @@ function(find_and_configure_faiss)
     )
 
     if(FAISS_ADDED)
-      set(FAISS_GPU_HEADERS ${FAISS_SOURCE_DIR} PARENT_SCOPE)
+      target_include_directories(faiss INTERFACE $<BUILD_INTERFACE:${FAISS_SOURCE_DIR}>)
       add_library(FAISS::FAISS ALIAS faiss)
     endif()
 

cpp/test/CMakeLists.txt

@@ -228,6 +228,9 @@ endif()
 # - build C-API test library -------------------------------------------------
 
 if(BUILD_CUML_C_LIBRARY)
+
+  enable_language(C)
+
   add_library(${CUML_C_TEST_TARGET} SHARED
     c_api/dbscan_api_test.c
     c_api/glm_api_test.c
@@ -236,8 +239,6 @@ if(BUILD_CUML_C_LIBRARY)
     c_api/svm_api_test.c
   )
 
-  set_target_properties(${CUML_C_TEST_TARGET} PROPERTIES LINKER_LANGUAGE C)
-
-  target_link_libraries(${CUML_C_TEST_TARGET} PUBLIC cuml_c)
+  target_link_libraries(${CUML_C_TEST_TARGET} PUBLIC ${CUML_C_TARGET})
 
 endif(BUILD_CUML_C_LIBRARY)