Arm backend: Use executorch_target_link_options_shared_lib()

CMakeLists.txt

@@ -1222,17 +1222,16 @@ if(EXECUTORCH_BUILD_EXECUTOR_RUNNER)
   if(NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
     target_link_options_gc_sections(executor_runner)
   endif()
-  target_link_libraries(executor_runner ${_executor_runner_libs})
+  target_link_libraries(executor_runner PRIVATE ${_executor_runner_libs})
   target_compile_options(executor_runner PUBLIC ${_common_compile_options})
   if(EXECUTORCH_BUILD_ARM_ETHOSU_LINUX)
-    target_sources(
-      executor_runner
-      PRIVATE
-        ${CMAKE_SOURCE_DIR}/examples/arm/executor_runner/ethosu_link_helper.cpp
-    )
     target_compile_definitions(
       executor_runner PRIVATE EXECUTORCH_BUILD_ARM_ETHOSU_LINUX=1
     )
+    target_link_libraries(
+      executor_runner
+      PRIVATE $<LINK_LIBRARY:WHOLE_ARCHIVE,executorch_delegate_ethos_u>
+    )
     # Wrap static linking like the delegate_runner to keep images
     # self-contained.
     target_link_options(

backends/arm/runtime/EthosUBackend.cpp

@@ -412,22 +412,11 @@ Backend EthosUBackend_id{"EthosUBackend", &EthosUBackend_backend};
 static executorch::runtime::Error EthosUBackend_registered =
     register_backend(EthosUBackend_id);
 
-/**
- * This function serves as a linker force-include mechanism to ensure the
- * EthosU backend module gets properly linked into the final executable,
- * even when it might otherwise be optimized out by the linker due to
- * linker options that remove unused code or data for example
- * if you link with --gc-sections
- * This function can be called from your runner to force the inclusion of
- * the EthosU backend module. As a bonus it will return the status of the
- * backend registration, so you can also check if the registration was
- * successful.
- */
-
-// Warning: This should not be considered to be an API and might get removed
-// without notice in a future release if a better way to solve this is
-// implemented.
-extern "C" executorch::runtime::Error
+// DEPRECATED in Executorch 1.2
+// Remove it from your code and make sure to add this to your CMAKE rules
+// instead:
+//   executorch_target_link_options_shared_lib(executorch_delegate_ethos_u)
+extern "C" ET_DEPRECATED executorch::runtime::Error
 executorch_delegate_EthosUBackend_registered() {
   return EthosUBackend_registered;
 }

examples/arm/executor_runner/CMakeLists.txt

@@ -77,6 +77,7 @@ set(ET_DIR_PATH
     "${CMAKE_CURRENT_SOURCE_DIR}/../../.."
     CACHE PATH "Path to ExecuTorch dir"
 )
+include(${ET_DIR_PATH}/tools/cmake/Utils.cmake)
 set(ET_BUILD_DIR_PATH
     "${ET_DIR_PATH}/cmake-out-arm"
     CACHE PATH "Path to ExecuTorch build/install dir"
@@ -223,6 +224,12 @@ execute_process(
 )
 target_link_options(arm_executor_runner PRIVATE "-T" "${LINK_FILE_OUT}")
 
+# Apply whole-archive helper where available to keep static initializers.
+executorch_target_link_options_shared_lib(executorch_delegate_ethos_u)
+executorch_target_link_options_shared_lib(quantized_kernels)
+executorch_target_link_options_shared_lib(cortex_m_kernels)
+executorch_target_link_options_shared_lib(portable_kernels)
+
 set(arm_executor_runner_link)
 list(
   APPEND
@@ -232,12 +239,10 @@ list(
   executorch
   quantized_ops_lib
   cortex_m_ops_lib
-  "-Wl,--whole-archive"
   executorch_delegate_ethos_u
   quantized_kernels
   cortex_m_kernels
   portable_kernels
-  "-Wl,--no-whole-archive"
   -Xlinker
   -Map=arm_executor_runner.map
 )

examples/arm/image_classification_example/runtime/CMakeLists.txt

@@ -95,11 +95,11 @@ target_link_libraries(
          cortex_m_ops_lib
 )
 
-# We need to include whole archive for the EthosUBackend
-target_link_libraries(
-  img_class_example PUBLIC "-Wl,--whole-archive" executorch_delegate_ethos_u
-                           "-Wl,--no-whole-archive"
-)
+# Apply whole-archive helper where available to keep static initializers.
+include(${ET_DIR_PATH}/tools/cmake/Utils.cmake)
+executorch_target_link_options_shared_lib(executorch_delegate_ethos_u)
+
+target_link_libraries(img_class_example PUBLIC executorch_delegate_ethos_u)
 
 if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   set(LINK_FILE_EXT ld)

examples/arm/zephyr/CMakeLists.txt

@@ -124,6 +124,7 @@ endif()
 
 # Set EXECUTORCH_ROOT for the Codegen.cmake file
 set(EXECUTORCH_ROOT ${EXECUTORCH_DIR})
+include(${EXECUTORCH_DIR}/tools/cmake/Utils.cmake)
 
 # Ensure the portable kernels target exists even when portable ops are disabled
 # in the global build.
@@ -137,7 +138,6 @@ if(NOT TARGET portable_kernels)
 endif()
 set(EXECUTORCH_OPS_LIB "")
 if(_EXECUTORCH_GEN_ZEPHYR_PORTABLE_OPS)
-  include(${EXECUTORCH_DIR}/tools/cmake/Utils.cmake)
   include(${EXECUTORCH_DIR}/tools/cmake/Codegen.cmake)
   if(NOT DEFINED EXECUTORCH_ENABLE_DTYPE_SELECTIVE_BUILD)
     set(EXECUTORCH_ENABLE_DTYPE_SELECTIVE_BUILD "")
@@ -237,10 +237,20 @@ if(CONFIG_CPU_CORTEX_M)
     target_link_libraries(app PRIVATE cortex_m_ops_lib)
   endif()
   if(TARGET cortex_m_kernels)
+    executorch_target_link_options_shared_lib(cortex_m_kernels)
     target_link_libraries(app PRIVATE cortex_m_kernels)
   endif()
 endif()
+if(TARGET quantized_kernels)
+  executorch_target_link_options_shared_lib(quantized_kernels)
+  target_link_libraries(app PRIVATE quantized_kernels)
+endif()
+if(TARGET portable_kernels)
+  executorch_target_link_options_shared_lib(portable_kernels)
+  target_link_libraries(app PRIVATE portable_kernels)
+endif()
 if(TARGET executorch_delegate_ethos_u)
+  executorch_target_link_options_shared_lib(executorch_delegate_ethos_u)
   target_link_libraries(app PRIVATE executorch_delegate_ethos_u)
 endif()
 if(TARGET ethosu_core_driver)

examples/arm/zephyr/src/arm_executor_runner.cpp

@@ -58,11 +58,6 @@ using executorch::runtime::Span;
 using executorch::runtime::Tag;
 using executorch::runtime::TensorInfo;
 
-#if defined(CONFIG_ETHOS_U)
-extern "C" executorch::runtime::Error
-executorch_delegate_EthosUBackend_registered(void);
-#endif
-
 /**
  * The method_allocation_pool should be large enough to fit the setup, input
  * used and other data used like the planned memory pool (e.g. memory-planned
@@ -214,14 +209,6 @@ int main(int argc, const char* argv[]) {
   (void)argc;
   (void)argv;
 
-#if defined(CONFIG_ETHOS_U)
-  if (executorch_delegate_EthosUBackend_registered() != Error::Ok) {
-    ET_LOG(
-        Error,
-        "Ethos-U backend registration failed; model execution cannot continue");
-    return 1;
-  }
-#endif
   executorch::runtime::runtime_init();
   std::vector<std::pair<char*, size_t>> input_buffers;
   size_t pte_size = sizeof(model_pte);