Support hosting WebAssembly demo page locally

To enhance the user experience of using WebAssembly version of rv32emu,
we shall provide a Makefile target (serve-wasm) to serve the WebAssembly
demo page in an easy way.

Since rv32emu leverages TCO (tail call optimization) when being compiled,
so we have to tell if the user's browser supports TCO. Currently, only
Chrome with MAJOR 112 and Firefox with MAJOR 121 supports TCO execution
runtime, thus we focus on this two browsers. Also, use color text to
remind the users if they need to update their Chrome or Firefox.

See also: #75

Author: ChinYikMing

Makefile

@@ -1,4 +1,5 @@
 include mk/common.mk
+include mk/color.mk
 include mk/toolchain.mk
 
 OUT ?= build
@@ -167,7 +168,7 @@ $(OUT)/emulate.o: CFLAGS += -foptimize-sibling-calls -fomit-frame-pointer -fno-s
 # to the first target after .DEFAULT_GOAL is not set.
 .DEFAULT_GOAL :=
 
-WEB_FILES += $(BIN).js \
+WEB_FILES := $(BIN).js \
 	     $(BIN).wasm \
 	     $(BIN).worker.js
 ifeq ("$(CC_IS_EMCC)", "1")
@@ -215,6 +216,69 @@ CFLAGS_emcc += -sINITIAL_MEMORY=2GB \
 
 # used to download all dependencies of elf executable and bundle into single wasm
 deps_emcc += $(DOOM_DATA) $(QUAKE_DATA) $(TIMIDITY_DATA)
+
+# check browser MAJOR version if supports TCO
+CHROME_MAJOR :=
+CHROME_MAJOR_VERSION_CHECK_CMD :=
+CHROME_SUPPORT_TCO_AT_MAJOR := 112
+CHROME_SUPPORT_TCO_INFO := Chrome supports TCO, you can use Chrome to request the wasm
+CHROME_NO_SUPPORT_TCO_WARNING := Chrome not found or Chrome must have at least version $(CHROME_SUPPORT_TCO_AT_MAJOR) in MAJOR to serve wasm
+
+FIREFOX_MAJOR :=
+FIREFOX_MAJOR_VERSION_CHECK_CMD :=
+FIREFOX_SUPPORT_TCO_AT_MAJOR := 121
+FIREFOX_SUPPORT_TCO_INFO := Firefox supports TCO, you can use Firefox to request the wasm
+FIREFOX_NO_SUPPORT_TCO_WARNING := Firefox not found or Firefox must have at least version $(FIREFOX_SUPPORT_TCO_AT_MAJOR) in MAJOR to serve wasm
+
+# FIXME: for Windows
+ifeq ($(UNAME_S),Darwin)
+    CHROME_MAJOR_VERSION_CHECK_CMD := "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome" --version | awk '{print $$3}' | cut -f1 -d.
+    FIREFOX_MAJOR_VERSION_CHECK_CMD := /Applications/Firefox.app/Contents/MacOS/firefox --version | awk '{print $$3}' | cut -f1 -d.
+else ifeq ($(UNAME_S),Linux)
+    CHROME_MAJOR_VERSION_CHECK_CMD := google-chrome --version | awk '{print $$3}' | cut -f1 -d.
+    FIREFOX_MAJOR_VERSION_CHECK_CMD := firefox -v | awk '{print $$3}' | cut -f1 -d.
+endif
+CHROME_MAJOR := $(shell $(CHROME_MAJOR_VERSION_CHECK_CMD))
+FIREFOX_MAJOR := $(shell $(FIREFOX_MAJOR_VERSION_CHECK_CMD))
+
+# Chrome
+ifeq ($(shell echo $(CHROME_MAJOR)\>=$(CHROME_SUPPORT_TCO_AT_MAJOR) | bc), 1)
+    $(info $(shell echo "$(GREEN)$(CHROME_SUPPORT_TCO_INFO)$(NC)"))
+else
+    $(warning $(shell echo "$(YELLOW)$(CHROME_NO_SUPPORT_TCO_WARNING)$(NC)"))
+endif
+
+# Firefox
+ifeq ($(shell echo $(FIREFOX_MAJOR)\>=$(FIREFOX_SUPPORT_TCO_AT_MAJOR) | bc), 1)
+    $(info $(shell echo "$(GREEN)$(FIREFOX_SUPPORT_TCO_INFO)$(NC)"))
+else
+    $(warning $(shell echo "$(YELLOW)$(FIREFOX_NO_SUPPORT_TCO_WARNING)$(NC)"))
+endif
+
+# used to serve wasm locally
+DEMO_DIR := demo
+DEMO_IP := 127.0.0.1
+DEMO_PORT := 8000
+
+# check if demo root directory exists and create it if not
+check-demo-dir-exist:
+	$(Q)if [ ! -d "$(DEMO_DIR)" ]; then \
+		mkdir -p "$(DEMO_DIR)"; \
+	fi
+
+# FIXME: without $(info) generates errors
+define cp-web-file
+    $(Q)cp $(1) $(DEMO_DIR)
+    $(info)
+endef
+
+# WEB_FILES could be cleaned and recompiled, thus do not mix these two files into WEB_FILES
+STATIC_WEB_FILES := assets/html/index.html assets/js/coi-serviceworker.min.js
+
+serve-wasm: $(BIN) check-demo-dir-exist
+	$(foreach T, $(WEB_FILES), $(call cp-web-file, $(T)))
+	$(foreach T, $(STATIC_WEB_FILES), $(call cp-web-file, $(T)))
+	$(Q)python3 -m http.server --bind $(DEMO_IP) $(DEMO_PORT) --directory $(DEMO_DIR)
 endif
 
 $(OUT)/%.o: src/%.c $(deps_emcc)
@@ -304,6 +368,7 @@ distclean: clean
 	-$(RM) $(DOOM_DATA) $(QUAKE_DATA)
 	$(RM) -r $(TIMIDITY_DATA)
 	$(RM) -r $(OUT)/id1
+	$(RM) -r $(DEMO_DIR)
 	$(RM) *.zip
 	$(RM) -r $(OUT)/mini-gdbstub
 	-$(RM) $(OUT)/.config

mk/color.mk

@@ -0,0 +1,3 @@
+YELLOW=\033[0;33m
+GREEN=\033[0;32m
+NC=\033[0m