llext: define add_llext_target() for llext compilation

This patch defines a generic function that encapsulates all the architecture-specific machinery needed to compile llexts from source files. Current tests are updated to use this function. Output and source files must be specified using the OUTPUT and SOURCES arguments. Only one source file is currently supported. Arch-specific flags will be added automatically. The C_FLAGS argument can be used to pass additional compiler flags to the compilation of the source file. Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
zephyrproject-rtos · Jan 12, 2024 · ee9a514 · ee9a514
1 parent 24acecb
commit ee9a514
Show file tree

Hide file tree

Showing 3 changed files with 87 additions and 28 deletions.
diff --git a/subsys/llext/CMakeLists.txt b/subsys/llext/CMakeLists.txt
@@ -1,5 +1,84 @@
 if(CONFIG_LLEXT)
+
+  # Include all llext kernel sources as a library target
   zephyr_library()
   zephyr_library_sources(llext.c llext_export.c buf_loader.c)
   zephyr_library_sources_ifdef(CONFIG_LLEXT_SHELL shell.c)
+
+  # Add a custom target that compiles a single source file to a .llext file.
+  #
+  # Output and source files must be specified using the OUTPUT and SOURCES
+  # arguments. Only one source file is currently supported.
+  #
+  # Arch-specific flags will be added automatically. The C_FLAGS argument
+  # can be used to pass additional compiler flags to the compilation of
+  # the source file.
+  #
+  # Example usage:
+  #   add_llext_target(hello_world
+  #     OUTPUT  ${PROJECT_BINARY_DIR}/hello_world.llext
+  #     SOURCES ${PROJECT_SOURCE_DIR}/src/llext/hello_world.c
+  #     C_FLAGS -Werror
+  #   )
+  # will compile the source file src/llext/hello_world.c to a file
+  # ${PROJECT_BINARY_DIR}/hello_world.llext, adding -Werror to the compilation.
+  #
+  function(add_llext_target target_name)
+    set(single_args OUTPUT)
+    set(multi_args SOURCES;C_FLAGS)
+    cmake_parse_arguments(PARSE_ARGV 1 LLEXT "${options}" "${single_args}" "${multi_args}")
+
+    # Output file must be provided
+    if(NOT LLEXT_OUTPUT)
+      message(FATAL_ERROR "add_llext_target: OUTPUT argument must be provided")
+    endif()
+
+    # Source list length must currently be 1
+    list(LENGTH LLEXT_SOURCES source_count)
+    if(NOT source_count EQUAL 1)
+      message(FATAL_ERROR "add_llext_target: only one source file is supported")
+    endif()
+
+    set(output_file ${LLEXT_OUTPUT})
+    set(source_file ${LLEXT_SOURCES})
+    get_filename_component(output_name ${output_file} NAME)
+
+    # Add user-visible target and dependency
+    add_custom_target(${target_name} ALL
+      COMMENT "Compiling ${output_name}"
+      DEPENDS ${output_file}
+    )
+
+    # Compile the source file to an .llext file
+    if(CONFIG_ARM)
+      list(PREPEND LLEXT_C_FLAGS "-mlong-calls" "-mthumb")
+      add_custom_command(OUTPUT ${output_file}
+        COMMAND ${CMAKE_C_COMPILER} ${LLEXT_C_FLAGS} -c
+                -I ${ZEPHYR_BASE}/include
+                -imacros ${AUTOCONF_H}
+                -o ${output_file}
+                ${source_file}
+        DEPENDS ${source_file}
+      )
+    elseif(CONFIG_XTENSA)
+      list(PREPEND LLEXT_C_FLAGS "-shared" "-fPIC" "-nostdlib" "-nodefaultlibs")
+      get_filename_component(output_dir ${output_file} DIRECTORY)
+      get_filename_component(output_name_we ${output_file} NAME_WE)
+      set(pre_output_file ${output_dir}/${output_name_we}.pre.llext)
+      add_custom_command(OUTPUT ${output_file}
+        COMMAND ${CMAKE_C_COMPILER} ${LLEXT_C_FLAGS}
+                -I ${ZEPHYR_BASE}/include
+                -imacros ${AUTOCONF_H}
+                -o ${pre_output_file}
+                ${source_file}
+        COMMAND ${CROSS_COMPILE}strip -R .xt.*
+                -o ${output_file}
+                ${pre_output_file}
+        DEPENDS ${source_file}
+      )
+    else()
+      message(FATAL_ERROR "add_llext_target: unsupported architecture")
+    endif()
+  endfunction()
+
 endif()
diff --git a/tests/subsys/llext/CMakeLists.txt b/tests/subsys/llext/CMakeLists.txt
@@ -23,4 +23,4 @@ generate_inc_file_for_target(
   ${gen_dir}/hello_world.inc
   )
 
-add_dependencies(app hello_world)
+add_dependencies(app hello_world_llext)
diff --git a/tests/subsys/llext/hello_world/CMakeLists.txt b/tests/subsys/llext/hello_world/CMakeLists.txt
@@ -12,34 +12,14 @@ elseif(CONFIG_MODULES AND NOT CONFIG_LLEXT_TEST_HELLO STREQUAL "m")
   message(FATAL_ERROR "CONFIG_LLEXT_TEST_HELLO must be set to 'm' when CONFIG_MODULES is enabled")
 else()
 
-# TODO check which architecture is being used
-if(CONFIG_ARM)
-    set(CMAKE_C_FLAGS "-mlong-calls" "-mthumb")
+  set(llext_src_file ${PROJECT_SOURCE_DIR}/hello_world.c)
+  set(llext_bin_file ${PROJECT_BINARY_DIR}/hello_world.llext)
 
-    add_custom_command(OUTPUT ${PROJECT_BINARY_DIR}/hello_world.llext
-	COMMAND ${CMAKE_C_COMPILER} ${CMAKE_C_FLAGS} -c
-		-I ${PROJECT_SOURCE_DIR}/../../../../include
-		-imacros${PROJECT_BINARY_DIR}/../zephyr/include/generated/autoconf.h
-		-o ${PROJECT_BINARY_DIR}/hello_world.llext
-		${PROJECT_SOURCE_DIR}/hello_world.c
-    )
-elseif(CONFIG_XTENSA)
-    set(CMAKE_C_FLAGS "-shared" "-fPIC" "-nostdlib" "-nodefaultlibs")
+  add_llext_target(hello_world_llext
+    OUTPUT  ${llext_bin_file}
+    SOURCES ${llext_src_file}
+  )
 
-    add_custom_command(OUTPUT ${PROJECT_BINARY_DIR}/hello_world.llext
-	COMMAND ${CMAKE_C_COMPILER} ${CMAKE_C_FLAGS}
-		-I ${PROJECT_SOURCE_DIR}/../../../../include
-		-imacros${PROJECT_BINARY_DIR}/../zephyr/include/generated/autoconf.h
-		-o ${PROJECT_BINARY_DIR}/hello_world.pre.llext
-		${PROJECT_SOURCE_DIR}/hello_world.c
-	COMMAND ${CROSS_COMPILE}strip -R .xt.*
-		-o ${PROJECT_BINARY_DIR}/hello_world.llext
-		${PROJECT_BINARY_DIR}/hello_world.pre.llext
-    )
-endif()
-
-set(HELLO_WORLD_LLEXT ${PROJECT_BINARY_DIR}/hello_world.llext PARENT_SCOPE)
-
-add_custom_target(hello_world DEPENDS ${PROJECT_BINARY_DIR}/hello_world.llext)
+  set(HELLO_WORLD_LLEXT ${llext_bin_file} PARENT_SCOPE)
 
 endif()