py: Update and rework build system for including external C modules.

How to use this feature is documented in docs/develop/cmodules.rst.

4 files changed, 23 insertions, 16 deletions

diff --git a/py/mkenv.mk b/py/mkenv.mk
index 5f4b11b6b..87e92ec6f 100644
--- a/py/mkenv.mk
+++ b/py/mkenv.mk
@@ -61,7 +61,6 @@ endif
 MAKE_FROZEN = $(PYTHON) $(TOP)/tools/make-frozen.py
 MPY_CROSS = $(TOP)/mpy-cross/mpy-cross
 MPY_TOOL = $(PYTHON) $(TOP)/tools/mpy-tool.py
-GEN_CMODULES = $(PYTHON) $(TOP)/tools/gen-cmodules.py
 
 all:
 .PHONY: all
diff --git a/py/mkrules.mk b/py/mkrules.mk
index 65d86834e..caa9527c7 100644
--- a/py/mkrules.mk
+++ b/py/mkrules.mk
@@ -20,12 +20,12 @@ endif
 # can be located. By following this scheme, it allows a single build rule
 # to be used to compile all .c files.
 
-vpath %.S . $(TOP)
+vpath %.S . $(TOP) $(USER_C_MODULES)
 $(BUILD)/%.o: %.S
 	$(ECHO) "CC $<"
 	$(Q)$(CC) $(CFLAGS) -c -o $@ $<
 
-vpath %.s . $(TOP)
+vpath %.s . $(TOP) $(USER_C_MODULES)
 $(BUILD)/%.o: %.s
 	$(ECHO) "AS $<"
 	$(Q)$(AS) -o $@ $<
@@ -42,14 +42,14 @@ $(Q)$(CC) $(CFLAGS) -c -MD -o $@ $<
   $(RM) -f $(@:.o=.d)
 endef
 
-vpath %.c . $(TOP)
+vpath %.c . $(TOP) $(USER_C_MODULES)
 $(BUILD)/%.o: %.c
 	$(call compile_c)
 
 QSTR_GEN_EXTRA_CFLAGS += -DNO_QSTR
 QSTR_GEN_EXTRA_CFLAGS += -I$(BUILD)/tmp
 
-vpath %.c . $(TOP)
+vpath %.c . $(TOP) $(USER_C_MODULES)
 
 $(BUILD)/%.pp: %.c
 	$(ECHO) "PreProcess $<"
@@ -105,7 +105,7 @@ endif
 ifneq ($(FROZEN_MPY_DIR),)
 # to build the MicroPython cross compiler
 $(TOP)/mpy-cross/mpy-cross: $(TOP)/py/*.[ch] $(TOP)/mpy-cross/*.[ch] $(TOP)/ports/windows/fmode.c
-	$(Q)$(MAKE) -C $(TOP)/mpy-cross USER_C_MODULES=
+	$(Q)$(MAKE) -C $(TOP)/mpy-cross
 
 # make a list of all the .py files that need compiling and freezing
 FROZEN_MPY_PY_FILES := $(shell find -L $(FROZEN_MPY_DIR) -type f -name '*.py' | $(SED) -e 's=^$(FROZEN_MPY_DIR)/==')
@@ -123,13 +123,6 @@ $(BUILD)/frozen_mpy.c: $(FROZEN_MPY_MPY_FILES) $(BUILD)/genhdr/qstrdefs.generate
 	$(Q)$(MPY_TOOL) -f -q $(BUILD)/genhdr/qstrdefs.preprocessed.h $(FROZEN_MPY_MPY_FILES) > $@
 endif
 
-# to build a list of modules for py/objmodule.c.
-ifneq ($(USER_C_MODULES),)
-$(BUILD)/genhdr/cmodules.h: | $(HEADER_BUILD)/mpversion.h
-	@$(ECHO) "GEN $@"
-	$(Q)$(GEN_CMODULES) $(USER_C_MODULES) > $@
-endif
-
 ifneq ($(PROG),)
 # Build a standalone executable (unix does this)
 
diff --git a/py/objmodule.c b/py/objmodule.c
index 04d210260..9191c73ec 100644
--- a/py/objmodule.c
+++ b/py/objmodule.c
@@ -31,6 +31,8 @@
 #include "py/runtime.h"
 #include "py/builtin.h"
 
+#include "genhdr/moduledefs.h"
+
 STATIC void module_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_module_t *self = MP_OBJ_TO_PTR(self_in);
diff --git a/py/py.mk b/py/py.mk
index ad7d12204..0fbc9f14b 100644
--- a/py/py.mk
+++ b/py/py.mk
@@ -131,9 +131,20 @@ endif
 
 # External modules written in C.
 ifneq ($(USER_C_MODULES),)
-CFLAGS_MOD += -DMICROPY_CMODULES_INCLUDE_H='"genhdr/cmodules.h"'
-include $(USER_C_MODULES)/*/micropython.mk
-SRC_QSTR += $(BUILD)/genhdr/cmodules.h
+# pre-define USERMOD variables as expanded so that variables are immediate 
+# expanded as they're added to them
+SRC_USERMOD := 
+CFLAGS_USERMOD :=
+LDFLAGS_USERMOD :=
+$(foreach module, $(wildcard $(USER_C_MODULES)/*/micropython.mk), \
+    $(eval USERMOD_DIR = $(patsubst %/,%,$(dir $(module))))\
+    $(info Including User C Module from $(USERMOD_DIR))\
+	$(eval include $(module))\
+)
+
+SRC_MOD += $(patsubst $(USER_C_MODULES)/%.c,%.c,$(SRC_USERMOD))
+CFLAGS_MOD += $(CFLAGS_USERMOD)
+LDFLAGS_MOD += $(LDFLAGS_USERMOD)
 endif
 
 # py object files
@@ -335,6 +346,8 @@ $(HEADER_BUILD)/moduledefs.h: $(SRC_QSTR) $(QSTR_GLOBAL_DEPENDENCIES) | $(HEADER
 	@$(ECHO) "GEN $@"
 	$(Q)$(PYTHON) $(PY_SRC)/makemoduledefs.py --vpath="., $(TOP), $(USER_C_MODULES)" $(SRC_QSTR) > $@
 
+SRC_QSTR += $(HEADER_BUILD)/moduledefs.h
+
 # Force nlr code to always be compiled with space-saving optimisation so
 # that the function preludes are of a minimal and predictable form.
 $(PY_BUILD)/nlr%.o: CFLAGS += -Os