Build: Add LLVM toolchain support for an521 only.

Support for other platforms will follow.

Signed-off-by: Anton Komlev <anton.komlev@arm.com>
Change-Id: Id036ecd78bf8e8909af30f78b2bfe5262b78c6b9
diff --git a/platform/ns/toolchain_ns_LLVM.cmake b/platform/ns/toolchain_ns_LLVM.cmake
new file mode 100644
index 0000000..9d066bd
--- /dev/null
+++ b/platform/ns/toolchain_ns_LLVM.cmake
@@ -0,0 +1,212 @@
+#-------------------------------------------------------------------------------
+# SPDX-License-Identifier: BSD-3-Clause
+# SPDX-FileCopyrightText: Copyright The TrustedFirmware-M Contributors
+#-------------------------------------------------------------------------------
+
+set(CMAKE_SYSTEM_NAME Generic)
+
+# Specify the cross compiler
+set(CMAKE_C_COMPILER clang)
+set(CMAKE_ASM_COMPILER clang)
+set(CMAKE_C_COMPILER_FORCED TRUE)
+set(CMAKE_ASM_COMPILER_FORCED TRUE)
+
+if(NOT DEFINED CROSS_COMPILE)
+    set(CROSS_COMPILE    arm-none-eabi CACHE STRING "Cross-compiler prefix")
+endif()
+set(CMAKE_C_COMPILER_TARGET ${CROSS_COMPILE})
+set(CMAKE_ASM_COMPILER_TARGET ${CROSS_COMPILE})
+
+set(CMAKE_USER_MAKE_RULES_OVERRIDE ${CMAKE_CURRENT_LIST_DIR}/set_extensions.cmake)
+
+# CMAKE_C_COMPILER_VERSION is not guaranteed to be defined.
+EXECUTE_PROCESS( COMMAND ${CMAKE_C_COMPILER} -dumpversion OUTPUT_VARIABLE LLVM_VERSION )
+if (LLVM_VERSION VERSION_LESS 18.1.3)
+    message(FATAL_ERROR "Please use newer LLVM compiler version starting from 18.1.3")
+endif()
+
+# ===================== Set toolchain CPU and Arch =============================
+# -mcpu gives better optimisation than -march so -mcpu shall be in preference
+
+if (TFM_SYSTEM_PROCESSOR)
+    if(TFM_SYSTEM_DSP)
+        string(APPEND TFM_SYSTEM_PROCESSOR "+dsp")
+    else()
+        string(APPEND TFM_SYSTEM_PROCESSOR "+nodsp")
+    endif()
+    if(CONFIG_TFM_ENABLE_FP)
+        string(APPEND TFM_SYSTEM_PROCESSOR "+fp")
+    else()
+        string(APPEND TFM_SYSTEM_PROCESSOR "+nofp")
+    endif()
+
+    set(CMAKE_C_FLAGS        "-mcpu=${TFM_SYSTEM_PROCESSOR}")
+    set(CMAKE_ASM_FLAGS      "-mcpu=${TFM_SYSTEM_PROCESSOR}")
+else()
+    if(CONFIG_TFM_ENABLE_FP)
+        string(APPEND TFM_SYSTEM_ARCHITECTURE "+fp")
+    endif()
+    if(TFM_SYSTEM_DSP)
+        string(APPEND TFM_SYSTEM_ARCHITECTURE "+dsp")
+    endif()
+    set(CMAKE_C_FLAGS        "-march=${TFM_SYSTEM_ARCHITECTURE}")
+    set(CMAKE_ASM_FLAGS      "-march=${TFM_SYSTEM_ARCHITECTURE}")
+    set(CMAKE_ASM_CPU_FLAG  ${TFM_SYSTEM_ARCHITECTURE})
+endif()
+
+if (CONFIG_TFM_FLOAT_ABI STREQUAL "hard")
+    set(COMPILER_CP_FLAG -mfloat-abi=hard)
+    set(LINKER_CP_OPTION -mfloat-abi=hard)
+    if (CONFIG_TFM_ENABLE_FP OR CONFIG_TFM_ENABLE_MVE_FP)
+        set(COMPILER_CP_FLAG -mfloat-abi=hard -mfpu=${CONFIG_TFM_FP_ARCH})
+        set(LINKER_CP_OPTION -mfloat-abi=hard -mfpu=${CONFIG_TFM_FP_ARCH})
+    endif()
+else()
+    set(COMPILER_CP_FLAG -mfloat-abi=soft)
+    set(LINKER_CP_OPTION -mfloat-abi=soft)
+endif()
+
+set(BL1_COMPILER_CP_FLAG -mfloat-abi=soft)
+set(BL1_LINKER_CP_OPTION -mfloat-abi=soft)
+
+set(BL2_COMPILER_CP_FLAG -mfloat-abi=soft)
+set(BL2_LINKER_CP_OPTION -mfloat-abi=soft)
+
+add_compile_options(
+     -Wno-ignored-optimization-argument
+     -Wno-unused-command-line-argument
+     -Wall
+     -Wno-error=cpp
+     -c
+     -fdata-sections
+     -ffunction-sections
+     -fno-builtin
+     -fshort-enums
+     -fshort-wchar
+     -funsigned-char
+     -std=c99
+)
+
+# Pointer Authentication Code and Branch Target Identification (PACBTI) Options
+# Not currently supported for LLVM.
+if(NOT ${CONFIG_TFM_BRANCH_PROTECTION_FEAT} STREQUAL BRANCH_PROTECTION_DISABLED)
+    message(FATAL_ERROR "BRANCH_PROTECTION NOT supported for LLVM")
+endif()
+
+add_link_options(
+    LINKER:-check-sections
+    LINKER:-fatal-warnings
+    LINKER:--gc-sections
+    LINKER:--print-memory-usage
+    LINKER:-lcrt0 -ldummyhost
+    LINKER:--Map=bin/tfm_ns.map
+)
+
+#add_compile_definitions($<$<STREQUAL:${TFM_SYSTEM_ARCHITECTURE},armv8.1-m.main>:__ARM_ARCH_8_1M_MAIN__=1>)
+
+# Specify the scatter file used to link `target`.
+# Behaviour for handling scatter files is so wildly divergent between compilers
+# that this macro is required.
+#
+# Vendor platform can set a scatter file as property INTERFACE_LINK_DEPENDS of platform_ns.
+# `target` can fetch the scatter file from platform_ns.
+#
+# Alternatively, NS build can call target_add_scatter_file() with the install directory of
+# scatter files.
+#     target_add_scatter_file(target, install_dir)
+#
+# target_add_scatter_file() fetch a scatter file from the install directory.
+macro(target_add_scatter_file target)
+
+    # Try if scatter_file is passed from platform_ns
+    get_target_property(scatter_file
+                        platform_ns
+                        INTERFACE_LINK_DEPENDS
+    )
+
+    # If scatter_file is not passed from platform_ns
+    # Try if any scatter file is exported in install directory
+    # The intall directory is passed as an optinal argument
+    if(${scatter_file} STREQUAL "scatter_file-NOTFOUND")
+        set(install_dir ${ARGN})
+        list(LENGTH install_dir nr_install_dir)
+
+        # If nr_install_dir == 1, search for sct file under install dir
+        if(${nr_install_dir} EQUAL 1)
+            file(GLOB scatter_file "${install_dir}/*.ldc")
+        endif()
+    endif()
+
+    if(NOT EXISTS ${scatter_file})
+        message(FATAL_ERROR "Unable to find NS scatter file ${scatter_file}")
+    endif()
+
+    add_library(${target}_scatter OBJECT)
+    target_sources(${target}_scatter
+        PRIVATE
+            ${scatter_file}
+    )
+
+    # Cmake cannot use generator expressions in the
+    # set_source_file_properties command, so instead we just parse the regex
+    # for the filename and set the property on all files, regardless of if
+    # the generator expression would evaluate to true or not.
+    string(REGEX REPLACE ".*>:(.*)>$" "\\1" SCATTER_FILE_PATH "${scatter_file}")
+    set_source_files_properties(${SCATTER_FILE_PATH}
+        PROPERTIES
+        LANGUAGE C
+        KEEP_EXTENSION True # Avoid *.o extension for the preprocessed file
+    )
+
+    target_link_libraries(${target}_scatter PRIVATE platform_region_defs)
+
+    target_compile_options(${target}_scatter PRIVATE -E -xc)
+
+    target_link_options(${target} PRIVATE -T $<TARGET_OBJECTS:${target}_scatter>)
+
+    add_dependencies(${target} ${target}_scatter)
+    set_target_properties(${target} PROPERTIES LINK_DEPENDS $<TARGET_OBJECTS:${target}_scatter>)
+
+endmacro()
+
+# Macro for converting the output *.axf file to finary files: bin, elf, hex
+macro(add_convert_to_bin_target target)
+    get_target_property(bin_dir ${target} RUNTIME_OUTPUT_DIRECTORY)
+
+    add_custom_target(${target}_bin
+        SOURCES ${bin_dir}/${target}.bin
+    )
+    add_custom_command(OUTPUT ${bin_dir}/${target}.bin
+        DEPENDS ${target}
+        COMMAND ${CMAKE_OBJCOPY}
+            -O binary $<TARGET_FILE:${target}>
+            ${bin_dir}/${target}.bin
+    )
+
+    add_custom_target(${target}_elf
+        SOURCES ${bin_dir}/${target}.elf
+    )
+    add_custom_command(OUTPUT ${bin_dir}/${target}.elf
+        DEPENDS ${target}
+        COMMAND ${CMAKE_OBJCOPY}
+            -O elf32-littlearm $<TARGET_FILE:${target}>
+            ${bin_dir}/${target}.elf
+    )
+
+    add_custom_target(${target}_hex
+        SOURCES ${bin_dir}/${target}.hex
+    )
+    add_custom_command(OUTPUT ${bin_dir}/${target}.hex
+        DEPENDS ${target}
+        COMMAND ${CMAKE_OBJCOPY}
+            -O ihex $<TARGET_FILE:${target}>
+            ${bin_dir}/${target}.hex
+    )
+
+    add_custom_target(${target}_binaries
+        ALL
+        DEPENDS ${target}_bin
+        DEPENDS ${target}_elf
+        DEPENDS ${target}_hex
+    )
+endmacro()