cmake: Add gcc support

This commit adds the option to cmake to build TF-M with GCC.

Change-Id: I7a5e3c915efa61620f1f0d34ed42cba5c174c562
Signed-off-by: Mate Toth-Pal <mate.toth-pal@arm.com>
diff --git a/cmake/Common/CompilerGNUARM63.cmake b/cmake/Common/CompilerGNUARM63.cmake
new file mode 100644
index 0000000..81c25bc
--- /dev/null
+++ b/cmake/Common/CompilerGNUARM63.cmake
@@ -0,0 +1,63 @@
+#-------------------------------------------------------------------------------
+# Copyright (c) 2017-2018, Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+#-------------------------------------------------------------------------------
+
+#This file contains settings to specify how GCC shall be used
+
+#Include some dependencies
+Include(Common/CompilerGNUARMCommon)
+Include(Common/Utils)
+
+check_gnuarm_input_vars("6.3")
+
+if(NOT DEFINED ARM_CPU_ARHITECTURE)
+	set(_NO_ARM_CPU_ARHITECTURE true)
+elseif (${ARM_CPU_ARHITECTURE} STREQUAL "ARM8-M-BASE")
+	string_append_unique_item(STRING CMAKE_C_FLAGS_CPU KEY "-march=" VAL "-march=armv8-m.base")
+	string_append_unique_item(STRING CMAKE_CXX_FLAGS_CPU KEY "-march=" VAL "-march=armv8-m.base")
+	string_append_unique_item(STRING CMAKE_ASM_FLAGS_CPU KEY "-march=" VAL "-march=armv8-m.base")
+	string_append_unique_item(STRING CMAKE_LINK_FLAGS_CPU KEY "-march=" VAL "-march=armv8-m.base")
+elseif(${ARM_CPU_ARHITECTURE} STREQUAL "ARM8-M-MAIN")
+	string_append_unique_item(STRING CMAKE_C_FLAGS_CPU KEY "-march=" VAL "-march=armv8-m.main")
+	string_append_unique_item(STRING CMAKE_CXX_FLAGS_CPU KEY "-march=" VAL "-march=armv8-m.main")
+	string_append_unique_item(STRING CMAKE_ASM_FLAGS_CPU KEY "-march=" VAL "-march=armv8-m.main")
+	string_append_unique_item(STRING CMAKE_LINK_FLAGS_CPU KEY "-march=" VAL "-march=armv8-m.main")
+elseif(${ARM_CPU_ARHITECTURE} STREQUAL "V7-M")
+	string_append_unique_item(STRING CMAKE_C_FLAGS_CPU KEY "-march=" VAL "-march=armv7-m")
+	string_append_unique_item(STRING CMAKE_CXX_FLAGS_CPU KEY "-march=" VAL "-march=armv7-m")
+	string_append_unique_item(STRING CMAKE_ASM_FLAGS_CPU KEY "-march=" VAL "-march=armv7-m")
+	string_append_unique_item(STRING CMAKE_LINK_FLAGS_CPU KEY "-march=" VAL "-march=armv7-m")
+else()
+	message(FATAL_ERROR "Unknown or unsupported ARM cpu architecture setting.")
+endif()
+
+#Prefer arhitecture definition over cpu type.
+if(NOT DEFINED ARM_CPU_ARHITECTURE)
+	if(NOT DEFINED ARM_CPU_TYPE)
+		string_append_unique_item(_NO_ARM_CPU_TYPE true)
+	elseif(${ARM_CPU_TYPE} STREQUAL "Cortex-M3")
+		string_append_unique_item (CMAKE_C_FLAGS_CPU "-mcpu=cortex-m3")
+		string_append_unique_item (CMAKE_CXX_FLAGS_CPU "-mcpu=cortex-m3")
+		string_append_unique_item (CMAKE_ASM_FLAGS_CPU "--cpu=Cortex-M3")
+		string_append_unique_item (CMAKE_LINK_FLAGS_CPU "--cpu=Cortex-M3")
+	elseif(${ARM_CPU_TYPE} STREQUAL "Cortex-M33")
+		string_append_unique_item (CMAKE_C_FLAGS_CPU "-mcpu=cortex-m33")
+		string_append_unique_item (CMAKE_CXX_FLAGS_CPU "-mcpu=cortex-m33")
+		string_append_unique_item (CMAKE_ASM_FLAGS_CPU "--cpu=Cortex-M33")
+		string_append_unique_item (CMAKE_LINK_FLAGS_CPU "--cpu=Cortex-M33")
+	elseif(${ARM_CPU_TYPE} STREQUAL "Cortex-M23")
+		string_append_unique_item (CMAKE_C_FLAGS_CPU "-mcpu=cortex-m23")
+		string_append_unique_item (CMAKE_CXX_FLAGS_CPU "-mcpu=cortex-m23")
+		string_append_unique_item (CMAKE_ASM_FLAGS_CPU "--cpu=Cortex-M23")
+		string_append_unique_item (CMAKE_LINK_FLAGS_CPU "--cpu=Cortex-M23")
+	else()
+		message(FATAL_ERROR "Unknown ARM cpu setting.")
+	endif()
+endif()
+
+if (_NO_ARM_CPU_TYPE AND _NO_ARM_CPU_ARHITECTURE)
+	message(FATAL_ERROR "Cannot set CPU specific compiler flags: neither the ARM CPU type nor the architecture is set.")
+endif()