Add top-level CMake backends target

ghstack-source-id: 0f4ee19
ghstack-comment-id: 3099241838
Pull-Request: #12689

Author: GregoryComer

CMakeLists.txt

@@ -351,6 +351,9 @@ add_library(executorch_core ${_executorch_core__srcs})
 # Legacy name alias.
 add_library(executorch_no_prim_ops ALIAS executorch_core)
 
+# A list of all configured backends.
+set(_executorch_backends "")
+
 target_link_libraries(executorch_core PRIVATE program_schema)
 if(ANDROID)
   target_link_libraries(executorch_core PUBLIC log)
@@ -494,6 +497,7 @@ install(FILES tools/cmake/Utils.cmake tools/cmake/executorch-config.cmake
 
 if(EXECUTORCH_BUILD_ARM_BAREMETAL)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/arm)
+  list(APPEND _executorch_backends executorch_delegate_ethos_u)
 endif()
 
 if(EXECUTORCH_BUILD_CADENCE)
@@ -502,30 +506,37 @@ endif()
 
 if(EXECUTORCH_BUILD_NXP_NEUTRON)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/nxp)
+  list(APPEND _executorch_backends executorch_delegate_neutron)
 endif()
 
 if(EXECUTORCH_BUILD_COREML)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/apple/coreml)
+  list(APPEND _executorch_backends coremldelegate)
 endif()
 
 if(EXECUTORCH_BUILD_MPS)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/apple/mps)
+  list(APPEND _executorch_backends mpsdelegate)
 endif()
 
 if(EXECUTORCH_BUILD_NEURON)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/mediatek)
+  list(APPEND _executorch_backends neuron_backend)
 endif()
 
 if(EXECUTORCH_BUILD_OPENVINO)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/openvino)
+  list(APPEND _executorch_backends openvino_backend)
 endif()
 
 if(EXECUTORCH_BUILD_QNN)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/qualcomm)
+  list(APPEND _executorch_backends qnn_executorch_backend)
 endif()
 
 if(EXECUTORCH_BUILD_XNNPACK)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/xnnpack)
+  list(APPEND _executorch_backends xnnpack_backend)
 endif()
 
 if(EXECUTORCH_BUILD_CORTEX_M)
@@ -689,6 +700,23 @@ if(EXECUTORCH_BUILD_KERNELS_QUANTIZED)
   target_link_options_shared_lib(quantized_ops_lib)
 endif()
 
+if(EXECUTORCH_BUILD_VULKAN)
+  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/vulkan)
+  list(APPEND _executorch_backends vulkan_backend)
+endif()
+
+# Top-level interface targets.
+add_library(executorch_backends INTERFACE)
+
+# A target containing all configured backends.
+target_link_libraries(executorch_backends INTERFACE ${_executorch_backends})
+
+install(
+  TARGETS executorch_backends
+  INCLUDES
+  DESTINATION ${_common_include_directories}
+)
+
 if(EXECUTORCH_BUILD_EXECUTOR_RUNNER)
   # Baseline libraries that executor_runner will link against.
   set(_executor_runner_libs executorch gflags)
@@ -741,10 +769,6 @@ if(EXECUTORCH_BUILD_EXECUTOR_RUNNER)
   endif()
 endif()
 
-if(EXECUTORCH_BUILD_VULKAN)
-  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/vulkan)
-endif()
-
 if(EXECUTORCH_BUILD_ANDROID_JNI)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/extension/android)
 endif()