[nrf fromtree] cmake/compiler: Add linker_script compiler property

This property specifies the flag used to pass the linker script filename
through the compiler front end tot he linker.

For clang, we use the general purpose linker-pass through -Wl flag with -T:
-Wl,-T as clang doesn't support -T.

For gcc, we use -T directly as this keeps the picolibc specs file from
inserting the picolibc linker script as well.

If the compiler doesn't specify a value, we continue to use -Wl,-T as
before.

Signed-off-by: Keith Packard <keithp@keithp.com>
(cherry picked from commit 424590f)

Author: keith-packard

CMakeLists.txt

@@ -469,8 +469,9 @@ if(CONFIG_USERSPACE)
 endif()
 
 get_property(TOPT GLOBAL PROPERTY TOPT)
-set_ifndef(  TOPT -Wl,-T) # clang doesn't pick -T for some reason and complains,
-                          # while -Wl,-T works for both, gcc and clang
+get_property(COMPILER_TOPT TARGET compiler PROPERTY linker_script)
+set_ifndef(  TOPT "${COMPILER_TOPT}")
+set_ifndef(  TOPT -Wl,-T) # Use this if the compiler driver doesn't set a value
 
 if(CONFIG_HAVE_CUSTOM_LINKER_SCRIPT)
   set(LINKER_SCRIPT ${APPLICATION_SOURCE_DIR}/${CONFIG_CUSTOM_LINKER_SCRIPT})

cmake/compiler/clang/compiler_flags.cmake

@@ -23,6 +23,9 @@ set_compiler_property(PROPERTY diagnostic -fcolor-diagnostics)
 # clang flag to save temporary object files
 set_compiler_property(PROPERTY save_temps -save-temps)
 
+# clang doesn't handle the -T flag
+set_compiler_property(PROPERTY linker_script -Wl,-T)
+
 #######################################################
 # This section covers flags related to warning levels #
 #######################################################

cmake/compiler/compiler_flags_template.cmake

@@ -106,6 +106,9 @@ set_compiler_property(PROPERTY debug)
 # Flags to save temporary object files
 set_compiler_property(PROPERTY save_temps)
 
+# Flag to specify linker script
+set_compiler_property(PROPERTY linker_script)
+
 set_compiler_property(PROPERTY no_common)
 
 # Flags for imacros. The specific header must be appended by user.

cmake/compiler/gcc/compiler_flags.cmake

@@ -182,6 +182,9 @@ set_compiler_property(PROPERTY debug -g)
 # Flags to save temporary object files
 set_compiler_property(PROPERTY save_temps -save-temps=obj)
 
+# Flag to specify linker script
+set_compiler_property(PROPERTY linker_script -T)
+
 # GCC 11 by default emits DWARF version 5 which cannot be parsed by
 # pyelftools. Can be removed once pyelftools supports v5.
 check_set_compiler_property(APPEND PROPERTY debug -gdwarf-4)