build: Add spdlog build dependency

spdlog is included and built from source, using the third_party/spdlog
submodule.

When Gloo is built as a static library, spdlog is used in its
header-only library form. When Gloo is built as a shared library, spdlog
is built statically and included.

A key goal is to make spdlog a dependency internal to Gloo only. Gloo
users should not have to install spdlog themselves.

This commit does not add any usages of spdlog in Gloo, just the build
infrastructure to use it.

Author: jackbondpreston-arm

CMakeLists.txt

@@ -98,6 +98,9 @@ endif()
 set(GLOO_INSTALL ON CACHE BOOL "")
 mark_as_advanced(GLOO_INSTALL)
 
+# Compile definitions for Gloo
+set(GLOO_COMPILE_DEFS)
+
 # Build shared or static libraries (override from parent project)
 if(BUILD_SHARED_LIBS)
   set(GLOO_STATIC_OR_SHARED SHARED CACHE STRING "")

cmake/Dependencies.cmake

@@ -2,6 +2,9 @@ set(gloo_DEPENDENCY_LIBS "")
 set(gloo_cuda_DEPENDENCY_LIBS "")
 set(gloo_hip_DEPENDENCY_LIBS "")
 
+# Dependency libraries for all Gloo targets (e.g. tests, benchmarks, etc.)
+set(gloo_ALL_TARGETS_DEPENDENCY_LIBS "")
+
 # Configure path to modules (for find_package)
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${PROJECT_SOURCE_DIR}/cmake/Modules/")
 
@@ -104,7 +107,7 @@ if(USE_MPI)
     message(STATUS "MPI libraries: " ${MPI_CXX_LIBRARIES})
     include_directories(SYSTEM ${MPI_CXX_INCLUDE_PATH})
     list(APPEND gloo_DEPENDENCY_LIBS ${MPI_CXX_LIBRARIES})
-    add_definitions(-DGLOO_USE_MPI=1)
+    list(APPEND GLOO_COMPILE_DEFS "GLOO_USE_MPI=1")
   else()
     message(WARNING "Not compiling with MPI support. Suppress this warning with -DUSE_MPI=OFF.")
     set(USE_MPI OFF)
@@ -199,3 +202,19 @@ if(BUILD_TEST)
     target_link_libraries(gtest INTERFACE ${GTEST_LIBRARIES})
   endif()
 endif()
+
+set(SPDLOG_BUILD_SHARED OFF CACHE BOOL "" FORCE)
+set(SPDLOG_BUILD_PIC ON CACHE BOOL "" FORCE)
+set(SPDLOG_FMT_EXTERNAL OFF CACHE BOOL "" FORCE)
+
+set(_save_BUILD_SHARED_LIBS ${BUILD_SHARED_LIBS})
+set(BUILD_SHARED_LIBS OFF)
+add_subdirectory(third_party/spdlog EXCLUDE_FROM_ALL)
+set(BUILD_SHARED_LIBS ${_save_BUILD_SHARED_LIBS})
+
+if(GLOO_STATIC_OR_SHARED STREQUAL "STATIC")
+  list(APPEND gloo_ALL_TARGETS_DEPENDENCY_LIBS $<BUILD_INTERFACE:spdlog::spdlog_header_only>)
+else()
+  list(APPEND gloo_ALL_TARGETS_DEPENDENCY_LIBS spdlog::spdlog)
+  list(APPEND GLOO_COMPILE_DEFS SPDLOG_COMPILED_LIB)
+endif()

gloo/CMakeLists.txt

@@ -147,10 +147,12 @@ if(USE_CUDA)
     cuda_add_library(gloo_cuda ${GLOO_CUDA_SRCS} ${GLOO_STATIC_OR_SHARED})
   endif()
   target_link_libraries(gloo_cuda gloo ${gloo_cuda_DEPENDENCY_LIBS})
+  set_property(TARGET gloo_cuda APPEND PROPERTY LINK_LIBRARIES ${gloo_ALL_TARGETS_DEPENDENCY_LIBS})
 endif()
 if(USE_ROCM)
   gloo_hip_add_library(gloo_hip ${GLOO_HIP_SRCS})
   target_link_libraries(gloo_hip gloo)
+  set_property(TARGET gloo_hip APPEND PROPERTY LINK_LIBRARIES ${gloo_ALL_TARGETS_DEPENDENCY_LIBS})
 endif()
 if(USE_LIBUV)
   target_link_libraries(gloo PRIVATE uv_a)
@@ -165,7 +167,8 @@ elseif(USE_TCP_OPENSSL_LOAD)
   target_link_libraries(gloo PRIVATE dl)
 endif()
 
-target_link_libraries(gloo PRIVATE ${gloo_DEPENDENCY_LIBS})
+target_link_libraries(gloo PRIVATE ${gloo_DEPENDENCY_LIBS} ${gloo_ALL_TARGETS_DEPENDENCY_LIBS})
+target_compile_definitions(gloo PRIVATE ${GLOO_COMPILE_DEFS})
 
 # Add Interface include directories that are relocatable.
 target_include_directories(gloo INTERFACE $<INSTALL_INTERFACE:include>)

gloo/benchmark/CMakeLists.txt

@@ -5,7 +5,7 @@ set(GLOO_BENCHMARK_SRCS
   )
 
 add_executable(benchmark ${GLOO_BENCHMARK_SRCS})
-target_link_libraries(benchmark gloo)
+target_link_libraries(benchmark gloo ${gloo_ALL_TARGETS_DEPENDENCY_LIBS})
 
 if(GLOO_INSTALL)
   install(TARGETS benchmark DESTINATION ${CMAKE_INSTALL_PREFIX}/bin)

gloo/examples/CMakeLists.txt

@@ -1,8 +1,8 @@
 if(MSVC)
     add_executable(example_reduce example_reduce.cc)
-    target_link_libraries(example_reduce gloo)
+    target_link_libraries(example_reduce gloo ${gloo_ALL_TARGETS_DEPENDENCY_LIBS})
     add_executable(example_allreduce example_allreduce.cc)
-    target_link_libraries(example_allreduce gloo)
+    target_link_libraries(example_allreduce gloo ${gloo_ALL_TARGETS_DEPENDENCY_LIBS})
 
     if(USE_LIBUV)
         add_custom_command(TARGET example_reduce POST_BUILD
@@ -12,7 +12,7 @@ if(MSVC)
     endif()
 else()
     add_executable(example1 example1.cc)
-    target_link_libraries(example1 gloo)
+    target_link_libraries(example1 gloo ${gloo_ALL_TARGETS_DEPENDENCY_LIBS})
     add_executable(looks_like_mpi looks_like_mpi.cc)
-    target_link_libraries(looks_like_mpi gloo)
+    target_link_libraries(looks_like_mpi gloo ${gloo_ALL_TARGETS_DEPENDENCY_LIBS})
 endif()

gloo/test/CMakeLists.txt

@@ -17,7 +17,7 @@ set(GLOO_TEST_SRCS
   "${CMAKE_CURRENT_SOURCE_DIR}/remote_key_test.cc"
   "${CMAKE_CURRENT_SOURCE_DIR}/send_recv_test.cc"
   )
-set(GLOO_TEST_LIBRARIES)
+set(GLOO_TEST_LIBRARIES ${gloo_ALL_TARGETS_DEPENDENCY_LIBS})
 
 if(${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
   list(APPEND GLOO_TEST_SRCS
@@ -64,7 +64,7 @@ if(USE_CUDA)
     else()
       cuda_add_executable(gloo_test_cuda ${GLOO_TEST_CUDA_SRCS})
     endif()
-    target_link_libraries(gloo_test_cuda gloo_cuda gtest OpenSSL::SSL OpenSSL::Crypto ${GLOO_CUDA_LIBRARIES})
+    target_link_libraries(gloo_test_cuda gloo_cuda gtest ${GLOO_TEST_LIBRARIES} ${GLOO_CUDA_LIBRARIES})
   endif()
 endif()
 
@@ -79,5 +79,5 @@ if(USE_ROCM)
     )
 
   gloo_hip_add_executable(gloo_test_hip ${GLOO_TEST_HIP_SRCS})
-  target_link_libraries(gloo_test_hip gloo_hip gtest OpenSSL::SSL OpenSSL::Crypto)
+  target_link_libraries(gloo_test_hip gloo_hip gtest ${GLOO_TEST_LIBRARIES})
 endif()