esp8266: Enable frozen bytecode, with scripts in modules/ subdir.

To start with, the critical scripts _boot.py and flashbdev.py are frozen
to improve performance and reduce RAM consumption.

Saves about 1000 bytes of heap RAM for a bare boot with filesystem.

esp8266/Makefile

@@ -8,9 +8,12 @@ MICROPY_PY_USSL = 1
 # include py core make definitions
 include ../py/py.mk
 
+MPY_CROSS = ../mpy-cross/mpy-cross
+MPY_TOOL = ../tools/mpy-tool.py
 MAKE_FROZEN = ../tools/make-frozen.py
 
 SCRIPTDIR = scripts
+FROZEN_MPY_DIR = modules
 PORT ?= /dev/ttyACM0
 BAUD ?= 115200
 CROSS_COMPILE = xtensa-lx106-elf-
@@ -131,6 +134,9 @@ DRIVERS_SRC_C = $(addprefix drivers/,\
 SRC_S = \
 	gchelper.s \
 
+FROZEN_MPY_PY_FILES := $(shell find $(FROZEN_MPY_DIR)/ -type f -name '*.py')
+FROZEN_MPY_MPY_FILES := $(addprefix $(BUILD)/,$(FROZEN_MPY_PY_FILES:.py=.mpy))
+
 OBJ =
 OBJ += $(PY_O)
 OBJ += $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
@@ -139,6 +145,7 @@ OBJ += $(addprefix $(BUILD)/, $(STM_SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(EXTMOD_SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(LIB_SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(DRIVERS_SRC_C:.c=.o))
+OBJ += $(BUILD)/$(BUILD)/frozen_mpy.o
 #OBJ += $(BUILD)/pins_$(BOARD).o
 
 # List of sources for qstr extraction
@@ -163,6 +170,17 @@ $(BUILD)/frozen.c: $(wildcard $(SCRIPTDIR)/*) $(CONFVARS_FILE)
 	$(ECHO) "Generating $@"
 	$(Q)$(MAKE_FROZEN) $(SCRIPTDIR) > $@
 
+# to build .mpy files from .py files
+$(BUILD)/$(FROZEN_MPY_DIR)/%.mpy: $(FROZEN_MPY_DIR)/%.py
+	@$(ECHO) "MPY $<"
+	$(Q)$(MKDIR) -p $(dir $@)
+	$(Q)$(MPY_CROSS) -o $@ -s $(^:$(FROZEN_MPY_DIR)/%=%) $^
+
+# to build frozen_mpy.c from all .mpy files
+$(BUILD)/frozen_mpy.c: $(FROZEN_MPY_MPY_FILES) $(BUILD)/genhdr/qstrdefs.generated.h
+	@$(ECHO) "Creating $@"
+	$(Q)$(PYTHON) $(MPY_TOOL) -f -q $(BUILD)/genhdr/qstrdefs.preprocessed.h $(FROZEN_MPY_MPY_FILES) > $@
+
 .PHONY: deploy
 
 deploy: $(BUILD)/firmware-combined.bin

esp8266/mpconfigport.h

@@ -74,7 +74,9 @@
 #define MICROPY_ERROR_REPORTING     (MICROPY_ERROR_REPORTING_NORMAL)
 #define MICROPY_STREAMS_NON_BLOCK   (1)
 #define MICROPY_MODULE_FROZEN_STR   (1)
+#define MICROPY_MODULE_FROZEN_MPY   (1)
 #define MICROPY_MODULE_FROZEN_LEXER mp_lexer_new_from_str32
+#define MICROPY_QSTR_EXTRA_POOL     mp_qstr_frozen_const_pool
 
 #define MICROPY_FATFS_ENABLE_LFN       (1)
 #define MICROPY_FATFS_RPATH            (2)