py,extmod: Add core cmake rule files.

These allow a port to use cmake natively instead of make.

Signed-off-by: Damien George <damien@micropython.org>
diff --git a/py/mkrules.cmake b/py/mkrules.cmake
new file mode 100644
index 0000000..bdff385
--- /dev/null
+++ b/py/mkrules.cmake
@@ -0,0 +1,128 @@
+# CMake fragment for MicroPython rules
+
+set(MICROPY_PY_QSTRDEFS "${MICROPY_PY_DIR}/qstrdefs.h")
+set(MICROPY_GENHDR_DIR "${CMAKE_BINARY_DIR}/genhdr")
+set(MICROPY_MPVERSION "${MICROPY_GENHDR_DIR}/mpversion.h")
+set(MICROPY_MODULEDEFS "${MICROPY_GENHDR_DIR}/moduledefs.h")
+set(MICROPY_QSTR_DEFS_LAST "${MICROPY_GENHDR_DIR}/qstr.i.last")
+set(MICROPY_QSTR_DEFS_SPLIT "${MICROPY_GENHDR_DIR}/qstr.split")
+set(MICROPY_QSTR_DEFS_COLLECTED "${MICROPY_GENHDR_DIR}/qstrdefs.collected.h")
+set(MICROPY_QSTR_DEFS_PREPROCESSED "${MICROPY_GENHDR_DIR}/qstrdefs.preprocessed.h")
+set(MICROPY_QSTR_DEFS_GENERATED "${MICROPY_GENHDR_DIR}/qstrdefs.generated.h")
+
+# Provide defaults for preprocessor flags if not already defined
+if(NOT MICROPY_CPP_FLAGS)
+    get_target_property(MICROPY_CPP_INC ${MICROPY_TARGET} INCLUDE_DIRECTORIES)
+    get_target_property(MICROPY_CPP_DEF ${MICROPY_TARGET} COMPILE_DEFINITIONS)
+endif()
+
+# Compute MICROPY_CPP_FLAGS for preprocessor
+list(APPEND MICROPY_CPP_INC ${MICROPY_CPP_INC_EXTRA})
+list(APPEND MICROPY_CPP_DEF ${MICROPY_CPP_DEF_EXTRA})
+set(_prefix "-I")
+foreach(_arg ${MICROPY_CPP_INC})
+    list(APPEND MICROPY_CPP_FLAGS ${_prefix}${_arg})
+endforeach()
+set(_prefix "-D")
+foreach(_arg ${MICROPY_CPP_DEF})
+    list(APPEND MICROPY_CPP_FLAGS ${_prefix}${_arg})
+endforeach()
+list(APPEND MICROPY_CPP_FLAGS ${MICROPY_CPP_FLAGS_EXTRA})
+
+find_package(Python3 REQUIRED COMPONENTS Interpreter)
+
+target_sources(${MICROPY_TARGET} PRIVATE
+    ${MICROPY_MPVERSION}
+    ${MICROPY_QSTR_DEFS_GENERATED}
+)
+
+# Command to force the build of another command
+
+add_custom_command(
+    OUTPUT MICROPY_FORCE_BUILD
+    COMMENT ""
+    COMMAND echo -n
+)
+
+# Generate mpversion.h
+
+add_custom_command(
+    OUTPUT ${MICROPY_MPVERSION}
+    COMMAND ${CMAKE_COMMAND} -E make_directory ${MICROPY_GENHDR_DIR}
+    COMMAND ${Python3_EXECUTABLE} ${MICROPY_DIR}/py/makeversionhdr.py ${MICROPY_MPVERSION}
+    DEPENDS MICROPY_FORCE_BUILD
+)
+
+# Generate moduledefs.h
+
+add_custom_command(
+    OUTPUT ${MICROPY_MODULEDEFS}
+    COMMAND ${Python3_EXECUTABLE} ${MICROPY_PY_DIR}/makemoduledefs.py --vpath="/" ${MICROPY_SOURCE_QSTR} > ${MICROPY_MODULEDEFS}
+    DEPENDS ${MICROPY_MPVERSION}
+        ${MICROPY_SOURCE_QSTR}
+)
+
+# Generate qstrs
+
+# If any of the dependencies in this rule change then the C-preprocessor step must be run.
+# It only needs to be passed the list of MICROPY_SOURCE_QSTR files that have changed since
+# it was last run, but it looks like it's not possible to specify that with cmake.
+add_custom_command(
+    OUTPUT ${MICROPY_QSTR_DEFS_LAST}
+    COMMAND ${Python3_EXECUTABLE} ${MICROPY_PY_DIR}/makeqstrdefs.py pp ${CMAKE_C_COMPILER} -E output ${MICROPY_GENHDR_DIR}/qstr.i.last cflags ${MICROPY_CPP_FLAGS} -DNO_QSTR sources ${MICROPY_SOURCE_QSTR}
+    DEPENDS ${MICROPY_MODULEDEFS}
+        ${MICROPY_SOURCE_QSTR}
+    VERBATIM
+)
+
+add_custom_command(
+    OUTPUT ${MICROPY_QSTR_DEFS_SPLIT}
+    COMMAND ${Python3_EXECUTABLE} ${MICROPY_PY_DIR}/makeqstrdefs.py split qstr ${MICROPY_GENHDR_DIR}/qstr.i.last ${MICROPY_GENHDR_DIR}/qstr _
+    COMMAND touch ${MICROPY_QSTR_DEFS_SPLIT}
+    DEPENDS ${MICROPY_QSTR_DEFS_LAST}
+    VERBATIM
+)
+
+add_custom_command(
+    OUTPUT ${MICROPY_QSTR_DEFS_COLLECTED}
+    COMMAND ${Python3_EXECUTABLE} ${MICROPY_PY_DIR}/makeqstrdefs.py cat qstr _ ${MICROPY_GENHDR_DIR}/qstr ${MICROPY_QSTR_DEFS_COLLECTED}
+    DEPENDS ${MICROPY_QSTR_DEFS_SPLIT}
+    VERBATIM
+)
+
+add_custom_command(
+    OUTPUT ${MICROPY_QSTR_DEFS_PREPROCESSED}
+    COMMAND cat ${MICROPY_PY_QSTRDEFS} ${MICROPY_QSTR_DEFS_COLLECTED} | sed "s/^Q(.*)/\"&\"/" | ${CMAKE_C_COMPILER} -E ${MICROPY_CPP_FLAGS} - | sed "s/^\\\"\\(Q(.*)\\)\\\"/\\1/" > ${MICROPY_QSTR_DEFS_PREPROCESSED}
+    DEPENDS ${MICROPY_QSTR_DEFS_COLLECTED}
+    VERBATIM
+)
+
+add_custom_command(
+    OUTPUT ${MICROPY_QSTR_DEFS_GENERATED}
+    COMMAND ${Python3_EXECUTABLE} ${MICROPY_PY_DIR}/makeqstrdata.py ${MICROPY_QSTR_DEFS_PREPROCESSED} > ${MICROPY_QSTR_DEFS_GENERATED}
+    DEPENDS ${MICROPY_QSTR_DEFS_PREPROCESSED}
+    VERBATIM
+)
+
+# Build frozen code if enabled
+
+if(MICROPY_FROZEN_MANIFEST)
+    set(MICROPY_FROZEN_CONTENT "${CMAKE_BINARY_DIR}/frozen_content.c")
+
+    target_sources(${MICROPY_TARGET} PRIVATE
+        ${MICROPY_FROZEN_CONTENT}
+    )
+
+    target_compile_definitions(${MICROPY_TARGET} PUBLIC
+        MICROPY_QSTR_EXTRA_POOL=mp_qstr_frozen_const_pool
+        MICROPY_MODULE_FROZEN_MPY=\(1\)
+    )
+
+    add_custom_command(
+        OUTPUT ${MICROPY_FROZEN_CONTENT}
+        COMMAND ${Python3_EXECUTABLE} ${MICROPY_DIR}/tools/makemanifest.py -o ${MICROPY_FROZEN_CONTENT} -v "MPY_DIR=${MICROPY_DIR}" -v "PORT_DIR=${MICROPY_PORT_DIR}" -b "${CMAKE_BINARY_DIR}" -f${MICROPY_CROSS_FLAGS} ${MICROPY_FROZEN_MANIFEST}
+        DEPENDS MICROPY_FORCE_BUILD
+            ${MICROPY_QSTR_DEFS_GENERATED}
+        VERBATIM
+    )
+endif()