CMake: refactor GigaDevice targets

Refactor all GigaDevice targets to be CMake buildsystem targets. This removes
the need for checking MBED_TARGET_LABELS repeatedly and allows us to be
more flexible in the way we include MBED_TARGET source in the build.

A side effect of this is it will allow us to support custom targets
without breaking the build for 'standard' targets, as we use CMake's
standard mechanism for adding build rules to the build system, rather
than implementing our own layer of logic to exclude files not needed for
the target being built. Using this approach, if an MBED_TARGET is not
linked to using `target_link_libraries` its source files will not be
added to the build. This means custom target source can be added to the
user's application CMakeLists.txt without polluting the build system
when trying to compile for a standard MBED_TARGET.

targets/TARGET_GigaDevice/CMakeLists.txt

@@ -1,13 +1,12 @@
 # Copyright (c) 2020 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
-if("GD32F30X" IN_LIST MBED_TARGET_LABELS)
-    add_subdirectory(TARGET_GD32F30X)
-elseif("GD32F4XX" IN_LIST MBED_TARGET_LABELS)
-    add_subdirectory(TARGET_GD32F4XX)
-endif()
+add_subdirectory(TARGET_GD32F30X)
+add_subdirectory(TARGET_GD32F4XX)
 
-target_include_directories(mbed-core
+add_library(mbed-gigadevice INTERFACE)
+
+target_include_directories(mbed-gigadevice
     INTERFACE
         .
 )

targets/TARGET_GigaDevice/TARGET_GD32F30X/CMakeLists.txt

@@ -1,38 +1,38 @@
 # Copyright (c) 2020 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
-if("GD32F307VG" IN_LIST MBED_TARGET_LABELS)
-    target_include_directories(mbed-core
-        INTERFACE
-            TARGET_GD32F307VG
-            TARGET_GD32F307VG/device
-    )
+add_library(mbed-gd32-f307vg INTERFACE)
 
-    target_sources(mbed-core
-        INTERFACE
-            TARGET_GD32F307VG/PeripheralPins.c
+target_include_directories(mbed-gd32-f307vg
+    INTERFACE
+        TARGET_GD32F307VG
+        TARGET_GD32F307VG/device
+)
 
-            TARGET_GD32F307VG/device/system_gd32f30x.c
-    )
+target_sources(mbed-gd32-f307vg
+    INTERFACE
+        TARGET_GD32F307VG/PeripheralPins.c
 
-    if(${MBED_TOOLCHAIN} STREQUAL "ARM")
-        set(LINKER_FILE TARGET_GD32F307VG/device/TOOLCHAIN_ARM_STD/gd32f307vg.sct)
-        set(STARTUP_FILE TARGET_GD32F307VG/device/TOOLCHAIN_ARM_STD/startup_gd32f30x_cl.S)
-    elseif(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
-        set(LINKER_FILE TARGET_GD32F307VG/device/TOOLCHAIN_GCC_ARM/GD32F307xG.ld)
-        set(STARTUP_FILE TARGET_GD32F307VG/device/TOOLCHAIN_GCC_ARM/startup_gd32f30x_cl.S)
-    endif()
+        TARGET_GD32F307VG/device/system_gd32f30x.c
+)
+
+if(${MBED_TOOLCHAIN} STREQUAL "ARM")
+    set(LINKER_FILE TARGET_GD32F307VG/device/TOOLCHAIN_ARM_STD/gd32f307vg.sct)
+    set(STARTUP_FILE TARGET_GD32F307VG/device/TOOLCHAIN_ARM_STD/startup_gd32f30x_cl.S)
+elseif(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
+    set(LINKER_FILE TARGET_GD32F307VG/device/TOOLCHAIN_GCC_ARM/GD32F307xG.ld)
+    set(STARTUP_FILE TARGET_GD32F307VG/device/TOOLCHAIN_GCC_ARM/startup_gd32f30x_cl.S)
 endif()
 
-set_property(GLOBAL PROPERTY MBED_TARGET_LINKER_FILE ${CMAKE_CURRENT_SOURCE_DIR}/${LINKER_FILE})
+add_library(mbed-gd32f30x INTERFACE)
 
-target_include_directories(mbed-core
+target_include_directories(mbed-gd32f30x
     INTERFACE
         .
         GD32F30x_standard_peripheral/Include
 )
 
-target_sources(mbed-core
+target_sources(mbed-gd32f30x
     INTERFACE
         analogin_api.c
         analogout_api.c
@@ -77,3 +77,8 @@ target_sources(mbed-core
 
         ${STARTUP_FILE}
 )
+
+mbed_set_linker_script(mbed-gd32f30x ${CMAKE_CURRENT_SOURCE_DIR}/${LINKER_FILE})
+
+target_link_libraries(mbed-gd32f30x INTERFACE mbed-gigadevice)
+target_link_libraries(mbed-gd32-f307vg INTERFACE mbed-gd32f30x)

targets/TARGET_GigaDevice/TARGET_GD32F4XX/CMakeLists.txt

@@ -1,17 +1,17 @@
 # Copyright (c) 2020 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
-if("GD32F450ZI" IN_LIST MBED_TARGET_LABELS)
-    target_include_directories(mbed-core
-        INTERFACE
-            TARGET_GD32F450ZI
-    )
+add_library(mbed-gd32-f450zi INTERFACE)
 
-    target_sources(mbed-core
-        INTERFACE
-            TARGET_GD32F450ZI/PeripheralPins.c
-    )
-endif()
+target_include_directories(mbed-gd32-f450zi
+    INTERFACE
+        TARGET_GD32F450ZI
+)
+
+target_sources(mbed-gd32-f450zi
+    INTERFACE
+        TARGET_GD32F450ZI/PeripheralPins.c
+)
 
 if(${MBED_TOOLCHAIN} STREQUAL "ARM")
     set(LINKER_FILE device/TOOLCHAIN_ARM_STD/gd32f450zi.sct)
@@ -21,16 +21,16 @@ elseif(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
     set(STARTUP_FILE device/TOOLCHAIN_GCC_ARM/startup_gd32f450.S)
 endif()
 
-set_property(GLOBAL PROPERTY MBED_TARGET_LINKER_FILE ${CMAKE_CURRENT_SOURCE_DIR}/${LINKER_FILE})
+add_library(mbed-gd32f4xx INTERFACE)
 
-target_include_directories(mbed-core
+target_include_directories(mbed-gd32f4xx
     INTERFACE
         .
         device
         GD32F4xx_standard_peripheral/Include
 )
 
-target_sources(mbed-core
+target_sources(mbed-gd32f4xx
     INTERFACE
         analogin_api.c
         analogout_api.c
@@ -84,3 +84,8 @@ target_sources(mbed-core
 
         ${STARTUP_FILE}
 )
+
+mbed_set_linker_script(mbed-gd32-f450zi ${CMAKE_CURRENT_SOURCE_DIR}/${LINKER_FILE})
+
+target_link_libraries(mbed-gd32f4xx INTERFACE mbed-gigadevice)
+target_link_libraries(mbed-gd32-f450zi INTERFACE mbed-gd32f4xx)