commit 866571c4d785a46aee41415bf47e6dc9e6e3a6cd
author Gabor Abonyi <gabor.abonyi@arm.com> Thu Oct 07 13:56:19 2021 +0200
committer Ken Liu <ken.liu@arm.com> Wed Oct 27 09:56:02 2021 +0200
tree 001f67abac465072e682c8dafec0af7547ce2635
parent 0f61c303a500f8329d5fbaac0bc256365b2b6641

Build: Add support for using target arch only

Add the ability to specify only target architecture without setting
target CPU. This commit adds support for GCC and ARMCLANG only.

For Armclang, set architecture is now checked against available arch
targets instead of processors. Modifiers (nodsp, nofp, nomve) is now
propagated to CMAKE_C_FLAGS in -march.

Use TFM_SYSTEM_ARCHITECTURE in CMakeListst.txt instead of previous
CMAKE_SYSTEM_ARCHITECTURE, which is not a CMAKE variable, to reduce
possible confusion with CMAKE_SYSTEM_ARCH which is a CMAKE variable
for Armclang.

Change-Id: If86e7ee82172374fb729f3e51ddfc411b7dd651e
Signed-off-by: Gabor Abonyi <gabor.abonyi@arm.com>

toolchain_GNUARM.cmake

diff --git a/toolchain_GNUARM.cmake b/toolchain_GNUARM.cmake
index 067101d..359f846 100644
--- a/toolchain_GNUARM.cmake
+++ b/toolchain_GNUARM.cmake
@@ -68,12 +68,31 @@
 endmacro()
 
 macro(tfm_toolchain_set_processor_arch)
-    set(CMAKE_SYSTEM_PROCESSOR ${TFM_SYSTEM_PROCESSOR})
-    set(CMAKE_SYSTEM_ARCHITECTURE ${TFM_SYSTEM_ARCHITECTURE})
+    if (DEFINED TFM_SYSTEM_PROCESSOR)
+        set(CMAKE_SYSTEM_PROCESSOR ${TFM_SYSTEM_PROCESSOR})
+
+        if (DEFINED TFM_SYSTEM_DSP)
+            if (NOT TFM_SYSTEM_DSP)
+                string(APPEND CMAKE_SYSTEM_PROCESSOR "+nodsp")
+            endif()
+        endif()
+    endif()
+
+    # CMAKE_SYSTEM_ARCH variable is not a built-in CMAKE variable. It is used to
+    # set the compile and link flags when TFM_SYSTEM_PROCESSOR is not specified.
+    # The variable name is choosen to align with the ARMCLANG toolchain file.
+    set(CMAKE_SYSTEM_ARCH         ${TFM_SYSTEM_ARCHITECTURE})
 
     if (DEFINED TFM_SYSTEM_DSP)
-        if(NOT TFM_SYSTEM_DSP)
-            string(APPEND CMAKE_SYSTEM_PROCESSOR "+nodsp")
+        # +nodsp modifier is only supported from GCC version 8.
+        # CMAKE_C_COMPILER_VERSION is not guaranteed to be defined.
+        EXECUTE_PROCESS( COMMAND ${CMAKE_C_COMPILER} -dumpversion OUTPUT_VARIABLE GCC_VERSION )
+        if(GCC_VERSION VERSION_GREATER_EQUAL "8.0.0")
+            # armv8.1-m.main arch does not have +nodsp option
+            if ((NOT TFM_SYSTEM_ARCHITECTURE STREQUAL "armv8.1-m.main") AND
+                NOT TFM_SYSTEM_DSP)
+                string(APPEND CMAKE_SYSTEM_ARCH "+nodsp")
+            endif()
         endif()
     endif()
 endmacro()
@@ -86,10 +105,17 @@
     unset(CMAKE_C_FLAGS_INIT)
     unset(CMAKE_ASM_FLAGS_INIT)
 
-    set(CMAKE_C_FLAGS_INIT "-mcpu=${CMAKE_SYSTEM_PROCESSOR}")
-    set(CMAKE_ASM_FLAGS_INIT "-mcpu=${CMAKE_SYSTEM_PROCESSOR}")
-    set(CMAKE_C_LINK_FLAGS "-mcpu=${CMAKE_SYSTEM_PROCESSOR}")
-    set(CMAKE_ASM_LINK_FLAGS "-mcpu=${CMAKE_SYSTEM_PROCESSOR}")
+    if (DEFINED TFM_SYSTEM_PROCESSOR)
+        set(CMAKE_C_FLAGS_INIT "-mcpu=${CMAKE_SYSTEM_PROCESSOR}")
+        set(CMAKE_ASM_FLAGS_INIT "-mcpu=${CMAKE_SYSTEM_PROCESSOR}")
+        set(CMAKE_C_LINK_FLAGS "-mcpu=${CMAKE_SYSTEM_PROCESSOR}")
+        set(CMAKE_ASM_LINK_FLAGS "-mcpu=${CMAKE_SYSTEM_PROCESSOR}")
+    else()
+        set(CMAKE_C_FLAGS_INIT "-march=${CMAKE_SYSTEM_ARCH}")
+        set(CMAKE_ASM_FLAGS_INIT "-march=${CMAKE_SYSTEM_ARCH}")
+        set(CMAKE_C_LINK_FLAGS "-march=${CMAKE_SYSTEM_ARCH}")
+        set(CMAKE_ASM_LINK_FLAGS "-march=${CMAKE_SYSTEM_ARCH}")
+    endif()
 
     set(CMAKE_C_FLAGS ${CMAKE_C_FLAGS_INIT})
     set(CMAKE_ASM_FLAGS ${CMAKE_ASM_FLAGS_INIT})