livecode · livecodeian · Apr 15, 2020 · Apr 15, 2020 · Apr 14, 2020 · Apr 14, 2020
diff --git a/Installer/package.txt b/Installer/package.txt
@@ -602,11 +602,17 @@ component Runtime.MacOSX
 
 component Runtime.Emscripten
 	into "[[ToolsFolder]]/Runtime/Emscripten/js" place
-		file emscripten:standalone[[BaseEditionTagLower]]-[[VersionTag]].html
-		file emscripten:standalone[[BaseEditionTagLower]]-[[VersionTag]].html.mem
-		file emscripten:standalone[[BaseEditionTagLower]]-[[VersionTag]].js
-		file emscripten:emscripten-startup-template.livecodescript
-		rfolder emscripten:emscripten-standalone-template
+		file emscripten-js:standalone[[BaseEditionTagLower]]-[[VersionTag]].html
+		file emscripten-js:standalone[[BaseEditionTagLower]]-[[VersionTag]].html.mem
+		file emscripten-js:standalone[[BaseEditionTagLower]]-[[VersionTag]].js
+		file emscripten-js:emscripten-startup-template.livecodescript
+		rfolder emscripten-js:emscripten-standalone-template
+	into "[[ToolsFolder]]/Runtime/Emscripten/wasm" place
+		file emscripten-wasm:standalone[[BaseEditionTagLower]]-[[VersionTag]].html
+		file emscripten-wasm:standalone[[BaseEditionTagLower]]-[[VersionTag]].js
+		file emscripten-wasm:standalone[[BaseEditionTagLower]]-[[VersionTag]].wasm
+		file emscripten-wasm:emscripten-startup-template.livecodescript
+		rfolder emscripten-wasm:emscripten-standalone-template
 
 //////////
 

diff --git a/Makefile b/Makefile
@@ -276,15 +276,21 @@ all-win-x86_64:
 # Emscripten rules
 ################################################################
 
-config-emscripten:
-	$(EMMAKE) ./config.sh --platform emscripten
+config-emscripten-%:
+	$(EMMAKE) ./config.sh --platform emscripten-$*
 
-compile-emscripten:
-	$(EMMAKE) $(MAKE) -C build-emscripten/livecode default
+compile-emscripten-%:
+	$(EMMAKE) $(MAKE) -C build-emscripten-$*/livecode default
 
-check-emscripten:
-	$(EMMAKE) $(MAKE) -C build-emscripten/livecode check
+check-emscripten-%:
+	$(EMMAKE) $(MAKE) -C build-emscripten-$*/livecode check
 
-all-emscripten:
-	$(MAKE) config-emscripten
-	$(MAKE) compile-emscripten
+all-emscripten-%:
+	$(MAKE) config-emscripten-$*
+	$(MAKE) compile-emscripten-$*
+
+#synonyms for *-emscripten-js
+all-emscripten: all-emscripten-js
+config-emscripten: config-emscripten-js
+compile-emscripten: compile-emscripten-js
+check-emscripten: check-emscripten-js
diff --git a/buildbot.py b/buildbot.py
@@ -74,6 +74,11 @@ def get_build_platform():
                 os.environ.get('BUILD_SUBPLATFORM'))
     if platform[0] is None:
         error('You must set $BUILD_PLATFORM')
+
+    # Assume js architecture for emscripten platform if not specified
+    if platform[0] is 'emscripten':
+        platform[0] = 'emscripten-js'
+
     return platform
 
 def get_buildtype():

diff --git a/config.py b/config.py
@@ -42,14 +42,15 @@
     'x86-win32', # TODO[2017-03-23] More specific ABI
     'x86_64-win32',
     'js-emscripten-sdk1.35',
+    'wasm-emscripten-sdk1.39',
 )
 
 KNOWN_PLATFORMS = (
     'linux-x86', 'linux-x86_64', 'linux-armv6hf', 'linux-armv7',
     'android-armv6', 'android-armv7', 'android-arm64', 'android-x86', 'android-x86_64',
     'mac', 'ios', 
     'win-x86', 'win-x86_64', 
-    'emscripten'
+    'emscripten', 'emscripten-js', 'emscripten-wasm',
 )
 
 def usage(exit_status):
@@ -288,10 +289,14 @@ def validate_target_arch(opts):
         validate_platform(opts)
 
         platform = opts['PLATFORM']
-        if platform == 'emscripten':
+        if platform in ['emscripten', 'emscripten-js']:
             opts['TARGET_ARCH'] = 'js'
             opts['UNIFORM_ARCH'] = opts['TARGET_ARCH']
             return
+        if platform == 'emscripten-wasm':
+            opts['TARGET_ARCH'] = 'wasm'
+            opts['UNIFORM_ARCH'] = opts['TARGET_ARCH']
+            return
 
         platform_arch = re.search('-(x86|x86_64|arm(64|v(6(hf)?|7)))$', platform)
         if platform_arch is not None:

diff --git a/config/arch.gypi b/config/arch.gypi
@@ -57,12 +57,6 @@
 						'host_os': 'linux',
 					},
 				],
-				[
-					'OS == "emscripten"',
-					{
-						'target_arch': 'js',
-					},
-				],
 			],
 		},
 

diff --git a/config/emscripten-settings.gypi b/config/emscripten-settings.gypi
@@ -22,8 +22,6 @@
 		'-s ALLOW_MEMORY_GROWTH=1',
 		'-s ASSERTIONS=1',
 		'-s DEMANGLE_SUPPORT=1',
-		'-s EMTERPRETIFY=1',
-		'-s EMTERPRETIFY_ASYNC=1',
 		'-s LINKABLE=1',
 		'-s RESERVED_FUNCTION_POINTERS=1024',
 		'-s TOTAL_MEMORY=67108864',
@@ -46,6 +44,23 @@
 
 	'target_conditions':
 	[
+		[
+			'toolset_arch == "wasm"',
+			{
+				'cflags':
+				[
+					'-s ASYNCIFY=1',
+					'-s', 'ASYNCIFY_IMPORTS=["MCEmscriptenAsyncYield"]',
+				],
+			},
+			{
+				'cflags':
+				[
+					'-s EMTERPRETIFY=1',
+					'-s EMTERPRETIFY_ASYNC=1',
+				]
+			},
+		],
 		[
 			'silence_warnings == 0',
 			{
@@ -101,7 +116,7 @@
 		{
 			'cflags':
 			[
-				'-Os',
+				'-O2',
 				'-g3',
 			],
 

diff --git a/config/emscripten.gypi b/config/emscripten.gypi
@@ -2,7 +2,7 @@
 	'variables':
 	{
 		'mobile': 1,
-		'output_dir': '../emscripten-bin',
+		'output_dir': '../emscripten-<(target_arch)-bin',
 	},
 
 	'target_defaults':

diff --git a/docs/development/build-emscripten.md b/docs/development/build-emscripten.md
@@ -2,7 +2,7 @@
 
 ![LiveCode Community Logo](http://livecode.com/wp-content/uploads/2015/02/livecode-logo.png)
 
-Copyright © 2015 LiveCode Ltd., Edinburgh, UK
+Copyright © 2020 LiveCode Ltd., Edinburgh, UK
 
 **Warning**: Emscripten (HTML5) platform support for LiveCode is experimental and not recommended for production use.
 
@@ -11,57 +11,121 @@ Copyright © 2015 LiveCode Ltd., Edinburgh, UK
 You will need a 64-bit Linux machine or VM with at least 4 GB of RAM
 (8 GB is recommended).
 
+## Emscripten build architectures
+
+There are two emscripten architectures that can be targeted for building the Emscripten engine, asm.js and WebAssembly. asm.js is based on a subset of JavaScript, whereas WebAssembly produces binary byte-code.
+
+## Building for asm.js
+
+The emscripten-js build target produces output in asm.js format that is converted to bytecode in order to be run through an interpreter. The emterpreted code can then be halted and resumed. This method of producing interruptable code is now deprecated but the tools are still available from the Emscripten SDK.
+
 ### Emscripten SDK
 
-Unsurprisingly, the Emscripten SDK must be installed in order to build
-an Emscripten engine.
+1. Download the Emscripten SDK. The recommended method for obtaining the Emscripten SDK is to use git tools to clone the emsdk repository from github. Other methods are described in <https://emscripten.org/docs/getting_started/downloads.html>. Put it in `/opt/emsdk_js`, for example.
 
-1. Download the portable Emscripten SDK from <https://kripken.github.io/emscripten-site>.  Put it in `/opt/emsdk_portable`, for example.
+       `git clone https://github.com/emscripten-core/emsdk /opt/emsdk_js`
 
-2. Check which SDKs are available by running:
+2. Check that the required tools are available by running:
 
-       /opt/emsdk_portable/emsdk list
+       `/opt/emsdk_js/emsdk list --old`
 
 3. Install and activate SDK 1.35.23 by running:
 
-       /opt/emsdk_portable/emsdk install sdk-1.35.23-32bit
-       /opt/emsdk_portable/emsdk activate sdk-1.35.23-32bit
+       `/opt/emsdk_js/emsdk install node-12.9.1-64bit`
+       `/opt/emsdk_js/emsdk activate --embedded node-12.9.1-64bit`
+       `/opt/emsdk_js/emsdk install emscripten-tag-1.35.23-64bit`
+       `/opt/emsdk_js/emsdk activate --embedded emscripten-tag-1.35.23-64bit`
+       `/opt/emsdk_js/emsdk install fastcomp-clang-tag-e1.35.23-64bit`
+       `/opt/emsdk_js/emsdk activate --embedded fastcomp-clang-tag-e1.35.23-64bit`
 
    This will take a really long time and use an insane amount of RAM.
 
-## Build environment
+### Build environment
+
+Before building for Emscripten, source the Emscripten SDK script that sets up the environment correctly.  You need to source it with the `.` or `source` command rather than just running it.
+
+    `source /opt/emsdk_js/emsdk_env.sh`
+
+### Configuring LiveCode
+
+To configure LiveCode, run:
+
+    `make config-emscripten-js`
+
+This will generate make control files in the `build-emscripten-js` directory.  You can also run `config.sh` directly.
+
+### Compiling LiveCode
+
+To compile LiveCode, run:
+
+    `make compile-emscripten-js`
+
+This will generate outputs in the `emscripten-bin-js` directory.
+
+## Building for WebAssembly
+
+The emscripten-wasm build target produces output in WebAssembly format that is then processed to allow the call stack to be saved and restored, making it possible for the engine execution to be halted and resumed. This is now the preferred method of generating interruptable code and can be built with the most recent version of the Emscripten SDK tools (version 1.39.12 as of April 2020).
+
+### Emscripten SDK
+
+1. Download the Emscripten SDK as described above. Put it in `/opt/emsdk_wasm`, for example.
+
+       `git clone https://github.com/emscripten-core/emsdk /opt/emsdk_wasm`
+
+2. Check that the required tools are available by running:
+
+       `/opt/emsdk_wasm/emsdk list`
+
+3. Install and activate SDK 1.39.12 by running:
+
+       `/opt/emsdk_wasm/emsdk install 1.39.12`
+       `/opt/emsdk_wasm/emsdk activate --embedded 1.39.12`
+
+### Build environment
 
 Before building for Emscripten, source the Emscripten SDK script that sets up the environment correctly.  You need to source it with the `.` or `source` command rather than just running it.
 
-    source /opt/emsdk_portable/emsdk_env.sh
+    `source /opt/emsdk_wasm/emsdk_env.sh`
 
-## Configuring LiveCode
+### Configuring LiveCode
 
 To configure LiveCode, run:
 
-    make config-emscripten
+    `make config-emscripten-wasm`
 
-This will generate make control files in the `build-emscripten` directory.  You can also run `config.sh` directly.
+This will generate make control files in the `build-emscripten-wasm` directory.  You can also run `config.sh` directly.
 
-## Compiling LiveCode
+### Compiling LiveCode
 
 To compile LiveCode, run:
 
-    make compile-emscripten
+    `make compile-emscripten-wasm`
 
-This will generate outputs in the `emscripten-bin` directory.
+This will generate outputs in the `emscripten-bin-wasm` directory.
 
 ## Running LiveCode
 
 **Note**: See also the "HTML5 Deployment" guide, available in the in-IDE dictionary.
 
+A desktop IDE built and launched from the repository checkout folder can be used to run HTML5 standalones with the emscripten engines compiled using the steps above.
+
+1. Enable emscripten output in the standalone settings for your stack. You can choose which architectures to include in the standalone output folder.
+
+2. Select a browser from the "Development -> Test Target" menu
+
+3. Click the "Test" button on the IDE toolbar.
+
+Your stack will be compiled to a HTML5 standalone and launched in the selected browser. If "WebAssembly" output is enabled in the standalone settings of the stack then the WebAssembly engine will be used when compiling the test app, otherwise the asm.js engine will be used.
+
+## Manual testing of HTML5 standalones. 
+
 Use the desktop build of the LiveCode IDE to run the standalone builder and create an "HTML5" standalone.
 
 Once you've created a standalone, you can open the HTML file in a web browser to try out the engine.
 
 Some web browsers (including Google Chrome) have JavaScript security policies that won't allow you to run the engine from a local filesystem.  For these browsers, you will need to run a local web server.  You can use the following steps to launch a local-only webserver listening on port 8080:
 
-    cd /path/to/my/standalone
-    python -m SimpleHTTPServer 8080
+    `cd /path/to/my/standalone`
+    `python -m SimpleHTTPServer 8080`
 
 You can then load http://localhost:8080/ in a web browser to view your standalone HTML5 engine.
diff --git a/docs/notes/feature-emscripten-webassembly.md b/docs/notes/feature-emscripten-webassembly.md
@@ -0,0 +1,14 @@
+# New WebAssembly option for HTML5 deployment of LiveCode apps (experimental)
+
+The LiveCode engine can now be deployed to HTML5 as WebAssembly.
+WebAssembly is supported in most major web browsers and allows HTML5
+apps to run at near-native speeds.
+
+To used WebAssembly when deploying a stack as an HTML5 application,
+enable the "Build for WebAssembly" checkbox on the "HTML5" page of the
+standalone settings window, and then generate the standalone in the
+normal way.
+
+For more information on HTML5 deployment, including options for
+embedding LiveCode standalones in web pages, please see the "HTML5
+Deployment" guide in the IDE dictionary.
-Original file line number
+Diff line change
@@ Expand Up / @@ -57,12 +57,6 @@ @@
     						'host_os': 'linux',
     					},
     				],
-    				[
-    					'OS == "emscripten"',
-    					{
-    						'target_arch': 'js',
-    					},
-    				],
     			],
     		},
@@ Expand Down @@