cmake: modules: add zephyr_library_relocate, to relocate zephyr library

Add zephyr_library_relocate, a helper macro intended to allow entire
Zephyr libraries to be relocated to a new memory region.

This is implemented via a two step process, to ensure that sources added
to a library after relocation is requested still are relocated:
1. zephyr_library_relocate adds a custom target property to the library
   with the relocation region and flags
2. the root level CMakeLists.txt captures this property while parsing all
   Zephyr libraries, and adds all library source files to the code
   relocation target

Signed-off-by: Daniel DeGrasse <[email protected]>

Author: danieldegrasse

CMakeLists.txt

@@ -91,6 +91,8 @@ set(PARSE_SYSCALLS_TARGET      parse_syscalls_target)
 
 define_property(GLOBAL PROPERTY PROPERTY_OUTPUT_FORMAT BRIEF_DOCS " " FULL_DOCS " ")
 set_property(   GLOBAL PROPERTY PROPERTY_OUTPUT_FORMAT elf32-little${ARCH}) # BFD format
+define_property(GLOBAL PROPERTY PROPERTY_CODE_RELOCATION_TARGET
+  BRIEF_DOCS "Code relocation target location" FULL_DOCS " ")
 
 # "zephyr_interface" is a source-less library that encapsulates all the global
 # compiler options needed by all source files. All zephyr libraries,
@@ -815,6 +817,21 @@ foreach(zephyr_lib ${ZEPHYR_LIBS_PROPERTY})
       list(REMOVE_ITEM ZEPHYR_LIBS_PROPERTY ${zephyr_lib})
       continue()
     endif()
+    # In order to allow zephyr_library_relocate to be called prior to adding
+    # library sources, we must parse and generate relocation information
+    # once all libraries have been defined
+    get_property(relocation_target TARGET ${zephyr_lib} PROPERTY
+      PROPERTY_CODE_RELOCATION_TARGET)
+    if(NOT "${relocation_target}" STREQUAL "")
+      get_property(lib_source_dir TARGET ${zephyr_lib} PROPERTY SOURCE_DIR)
+      foreach(file ${source_list})
+        if(NOT IS_ABSOLUTE ${file})
+          set(file ${lib_source_dir}/${file})
+        endif()
+        set_property(TARGET code_data_relocation_target APPEND PROPERTY
+          COMPILE_DEFINITIONS "${relocation_target}:${file}")
+      endforeach()
+    endif()
   endif()
 
   # TODO: Could this become an INTERFACE property of zephyr_interface?

cmake/modules/extensions.cmake

@@ -1281,6 +1281,20 @@ function(zephyr_linker_sources location)
   endforeach()
 endfunction(zephyr_linker_sources)
 
+function(zephyr_library_relocate location)
+  set(options NOCOPY)
+  cmake_parse_arguments(CODE_REL "${options}" "" "" ${ARGN})
+  if(NOT CODE_REL_NOCOPY)
+    set(copy_flag COPY)
+  else()
+    set(copy_flag NOCOPY)
+  endif()
+  # Set current library relocation property. This will be picked up
+  # in the root CMakeLists.txt file to relocate all sources added to
+  # this library
+  set_property(TARGET ${ZEPHYR_CURRENT_LIBRARY}
+    PROPERTY PROPERTY_CODE_RELOCATION_TARGET "${location}:${copy_flag}")
+endfunction()
 
 # Helper function for CONFIG_CODE_DATA_RELOCATION
 # Call this function with 2 arguments file and then memory location.