CMake: Add support for printf lib selection

CMakeLists.txt

@@ -48,9 +48,18 @@ elseif(NOT ${MBED_C_LIB} IN_LIST MBED_TARGET_SUPPORTED_C_LIBS)
     )
 endif()
 
+# Validate selected printf library
+set(MBED_PRINTF_LIB_TYPES std minimal-printf)
+if(NOT ${MBED_PRINTF_LIB} IN_LIST MBED_PRINTF_LIB_TYPES)
+    message(FATAL_ERROR
+        "Invalid printf library type '${MBED_PRINTF_LIB}'. Possible values:\n ${MBED_PRINTF_LIB_TYPES}"
+    )
+endif()
+
 mbed_set_cpu_core_options(mbed-os ${MBED_TOOLCHAIN})
 mbed_set_toolchain_options(mbed-os)
 mbed_set_c_lib(mbed-os ${MBED_C_LIB})
+mbed_set_printf_lib(mbed-os ${MBED_PRINTF_LIB})
 mbed_set_language_standard(mbed-os)
 mbed_set_profile_options(mbed-os ${MBED_TOOLCHAIN})
 

docs/design-documents/tools/cmake.md

@@ -98,6 +98,7 @@ This will output `mbed_config.cmake` in a directory named `.mbedbuild` at the ro
 * `MBED_CPU_CORE`
 * `MBED_C_LIB`
 * `MBED_TARGET_SUPPORTED_C_LIBS`
+* `MBED_PRINTF_LIB`
 
 The tools also generate an `MBED_TARGET_LABELS` variable, containing the labels, components and feature definitions from `targets.json`, used to select the required Mbed OS components to be built.
 

tools/cmake/toolchains/ARM.cmake

@@ -79,3 +79,13 @@ function(mbed_set_c_lib target lib_type)
         )
     endif()
 endfunction()
+
+# Configure the toolchain to select the selected printf library
+function(mbed_set_printf_lib target lib_type)
+    if (${lib_type} STREQUAL "minimal-printf")
+        target_compile_definitions(${target}
+            PUBLIC
+                MBED_MINIMAL_PRINTF
+        )
+    endif()
+endfunction()

tools/cmake/toolchains/GCC_ARM.cmake

@@ -91,3 +91,28 @@ function(mbed_set_c_lib target lib_type)
         )
     endif()
 endfunction()
+
+# Configure the toolchain to select the selected printf library
+function(mbed_set_printf_lib target lib_type)
+    if (${lib_type} STREQUAL "minimal-printf")
+        target_compile_definitions(${target}
+            PUBLIC
+                MBED_MINIMAL_PRINTF
+        )
+
+        list(APPEND link_options
+            "-Wl,--wrap,printf"
+            "-Wl,--wrap,sprintf"
+            "-Wl,--wrap,snprintf"
+            "-Wl,--wrap,vprintf"
+            "-Wl,--wrap,vsprintf"
+            "-Wl,--wrap,vsnprintf"
+            "-Wl,--wrap,fprintf"
+            "-Wl,--wrap,vfprintf"
+        )
+        target_link_options(${target}
+            PUBLIC
+                ${link_options}
+        )
+    endif()
+endfunction()