Inline ww.js file into the main output file

Similar to what we did for pthreads in emscripten-core#21701.

This is win for both code size and complexity.

Author: sbc100

src/lib/libwasm_worker.js

@@ -4,15 +4,6 @@
  * SPDX-License-Identifier: MIT
  */
 
-#if WASM_WORKERS == 2
-// Helpers for _wasmWorkerBlobUrl used in WASM_WORKERS == 2 mode
-{{{
-  const captureModuleArg = () => MODULARIZE ? '' : 'self.Module=d;';
-  const instantiateModule = () => MODULARIZE ? `${EXPORT_NAME}(d);` : '';
-  const instantiateWasm = () => MINIMAL_RUNTIME ? '' : 'd[`instantiateWasm`]=(i,r)=>{var n=new WebAssembly.Instance(d[`wasm`],i);return r(n,d[`wasm`]);};';
-}}}
-#endif
-
 #if WASM_WORKERS
 
 #if !SHARED_MEMORY
@@ -34,14 +25,19 @@
 {{{
   const workerSupportsFutexWait = () => AUDIO_WORKLET ? "typeof AudioWorkletGlobalScope === 'undefined'" : '1';
   const wasmWorkerJs = `
-#if WASM_WORKERS == 2
-    _wasmWorkerBlobUrl
-#elif MINIMAL_RUNTIME
+#if MINIMAL_RUNTIME
     Module['$wb']
 #else
-    locateFile('${WASM_WORKER_FILE}')
+    locateFile('${TARGET_JS_NAME}')
 #endif
 `;
+  const wasmWorkerOptions = `{
+#if ENVIRONMENT_MAY_BE_NODE
+        // This is the way that we signal to the node worker that it is hosting
+        // a wasm worker.
+        'workerData': 'em-ww',
+#endif
+}`;
 }}}
 
 #endif // ~WASM_WORKERS
@@ -83,7 +79,7 @@ addToLibrary({
 #endif
   ],
   $_wasmWorkerInitializeRuntime: () => {
-    let m = Module;
+    let m = wasmWorkerArgs;
 #if ASSERTIONS
     assert(m['sb'] % 16 == 0);
     assert(m['sz'] % 16 == 0);
@@ -142,20 +138,9 @@ addToLibrary({
 #endif
   },
 
-#if WASM_WORKERS == 2
-  // In WASM_WORKERS == 2 build mode, we create the Wasm Worker global scope
-  // script from a string bundled in the main application JS file. This
-  // simplifies the number of deployed JS files with the app, but has a downside
-  // that the generated build output will no longer be csp-eval compliant.
-  // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src#unsafe_eval_expressions
-  $_wasmWorkerBlobUrl: "URL.createObjectURL(new Blob(['onmessage=function(d){onmessage=null;d=d.data;{{{ captureModuleArg() }}}{{{ instantiateWasm() }}}importScripts(d.js);{{{ instantiateModule() }}}d.wasm=d.mem=d.js=0;}'],{type:'application/javascript'}))",
-#endif
   _emscripten_create_wasm_worker__deps: [
     '$_wasmWorkers', '$_wasmWorkersID',
     '$_wasmWorkerAppendToQueue', '$_wasmWorkerRunPostMessage',
-#if WASM_WORKERS == 2
-    '$_wasmWorkerBlobUrl',
-#endif
 #if ASSERTIONS
     'emscripten_has_threading_support',
 #endif
@@ -167,7 +152,7 @@ if (ENVIRONMENT_IS_WASM_WORKER
   && !ENVIRONMENT_IS_AUDIO_WORKLET
 #endif
   ) {
-  _wasmWorkers[0] = this;
+  _wasmWorkers[0] = globalThis;
   addEventListener("message", _wasmWorkerAppendToQueue);
 }`,
   _emscripten_create_wasm_worker: (stackLowestAddress, stackSize) => {
@@ -184,10 +169,10 @@ if (ENVIRONMENT_IS_WASM_WORKER
       var p = trustedTypes.createPolicy(
           'emscripten#workerPolicy1', { createScriptURL: (ignored) => {{{ wasmWorkerJs }}}}
       );
-      worker = _wasmWorkers[_wasmWorkersID] = new Worker(p.createScriptURL('ignored'));
+      worker = _wasmWorkers[_wasmWorkersID] = new Worker(p.createScriptURL('ignored'), {{{ wasmWorkerOptions }}});
     } else
 #endif
-    worker = _wasmWorkers[_wasmWorkersID] = new Worker({{{ wasmWorkerJs }}});
+    worker = _wasmWorkers[_wasmWorkersID] = new Worker({{{ wasmWorkerJs }}}, {{{ wasmWorkerOptions }}});
     // Craft the Module object for the Wasm Worker scope:
     worker.postMessage({
       // Signal with a non-zero value that this Worker will be a Wasm Worker,

src/postamble_minimal.js

@@ -95,7 +95,7 @@ var wasmExports;
 var wasmModule;
 #endif
 
-#if PTHREADS
+#if PTHREADS || WASM_WORKERS
 function loadModule() {
   assignWasmImports();
 #endif
@@ -255,12 +255,10 @@ WebAssembly.instantiate(Module['wasm'], imports).then((output) => {
 #endif // ASSERTIONS || WASM == 2
 );
 
-#if PTHREADS
+#if PTHREADS || WASM_WORKERS
 }
 
-if (!ENVIRONMENT_IS_PTHREAD) {
-  // When running in a pthread we delay module loading untill we have
-  // received the module via postMessage
-  loadModule();
-}
+// When running in a background thread we delay module loading until we have
+// received the module via postMessage
+{{{ runIfMainThread('loadModule();') }}}
 #endif

src/preamble.js

@@ -248,9 +248,7 @@ function exitRuntime() {
 #if STACK_OVERFLOW_CHECK
   checkStackCookie();
 #endif
-#if PTHREADS
-  if (ENVIRONMENT_IS_PTHREAD) return; // PThreads reuse the runtime from the main thread.
-#endif
+  {{{ runIfWorkerThread('return;') }}} // PThreads reuse the runtime from the main thread.
 #if !STANDALONE_WASM
   ___funcs_on_exit(); // Native atexit() functions
 #endif
@@ -266,9 +264,7 @@ function postRun() {
 #if STACK_OVERFLOW_CHECK
   checkStackCookie();
 #endif
-#if PTHREADS
-  if (ENVIRONMENT_IS_PTHREAD) return; // PThreads reuse the runtime from the main thread.
-#endif
+  {{{ runIfWorkerThread('return;') }}} // PThreads reuse the runtime from the main thread.
 
 #if expectToReceiveOnModule('postRun')
   if (Module['postRun']) {
@@ -823,7 +819,7 @@ async function instantiateAsync(binary, binaryFile, imports) {
 
 #if !WASM_ESM_INTEGRATION
 function getWasmImports() {
-#if PTHREADS
+#if PTHREADS || WASM_WORKERS
   assignWasmImports();
 #endif
 #if ASYNCIFY && (ASSERTIONS || ASYNCIFY == 2)
@@ -1008,8 +1004,8 @@ function getWasmImports() {
   }
 #endif
 
-#if PTHREADS
-  if (ENVIRONMENT_IS_PTHREAD) {
+#if PTHREADS || WASM_WORKERS
+  if ({{{ ENVIRONMENT_IS_WORKER_THREAD() }}}) {
     return new Promise((resolve) => {
       wasmModuleReceived = (module) => {
         // Instantiate from the module posted from the main thread.

src/runtime_debug.js

@@ -193,7 +193,7 @@ var runtimeDebug = true; // Switch to false at runtime to disable logging at the
 // Used by XXXXX_DEBUG settings to output debug messages.
 function dbg(...args) {
   if (!runtimeDebug && typeof runtimeDebug != 'undefined') return;
-#if ENVIRONMENT_MAY_BE_NODE && PTHREADS
+#if ENVIRONMENT_MAY_BE_NODE && (PTHREADS || WASM_WORKERS)
   // Avoid using the console for debugging in multi-threaded node applications
   // See https://github.com/emscripten-core/emscripten/issues/14804
   if (ENVIRONMENT_IS_NODE) {

src/runtime_init_memory.js

@@ -12,9 +12,7 @@
 // check for full engine support (use string 'subarray' to avoid closure compiler confusion)
 
 function initMemory() {
-#if PTHREADS
-  if (ENVIRONMENT_IS_PTHREAD) return;
-#endif // PTHREADS
+  {{{ runIfWorkerThread('return') }}}
 
 #if expectToReceiveOnModule('wasmMemory')
   if (Module['wasmMemory']) {

src/runtime_pthread.js

@@ -21,10 +21,6 @@ var sharedModules = {};
 #endif
 
 if (ENVIRONMENT_IS_PTHREAD) {
-#if !MINIMAL_RUNTIME
-  var wasmModuleReceived;
-#endif
-
 #if ENVIRONMENT_MAY_BE_NODE
   // Node.js support
   if (ENVIRONMENT_IS_NODE) {

src/runtime_shared.js

@@ -21,10 +21,18 @@
 #include "runtime_asan.js"
 #endif
 
+#if !MINIMAL_RUNTIME && (PTHREADS || WASM_WORKERS)
+var wasmModuleReceived;
+#endif
+
 #if PTHREADS
 #include "runtime_pthread.js"
 #endif
 
+#if WASM_WORKERS
+#include "wasm_worker.js"
+#endif
+
 #if LOAD_SOURCE_MAP
 var wasmSourceMap;
 #include "source_map_support.js"

src/settings.js

@@ -1637,13 +1637,9 @@ var USE_SQLITE3 = false;
 // [compile+link] - affects user code at compile and system libraries at link.
 var SHARED_MEMORY = false;
 
-// If 1, enables support for Wasm Workers. Wasm Workers enable applications
+// Enables support for Wasm Workers.  Wasm Workers enable applications
 // to create threads using a lightweight web-specific API that builds on top
-// of Wasm SharedArrayBuffer + Atomics API. When enabled, a new build output
-// file a.ww.js will be generated to bootstrap the Wasm Worker JS contexts.
-// If 2, enables support for Wasm Workers, but without using a separate a.ww.js
-// file on the side. This can simplify deployment of builds, but will have a
-// downside that the generated build will no longer be csp-eval compliant.
+// of Wasm SharedArrayBuffer + Atomics API.
 // [compile+link] - affects user code at compile and system libraries at link.
 var WASM_WORKERS = 0;
 

src/settings_internal.js

@@ -134,9 +134,6 @@ var USER_EXPORTS = [];
 // name of the file containing wasm binary, if relevant
 var WASM_BINARY_FILE = '';
 
-// name of the file containing the Wasm Worker *.ww.js, if relevant
-var WASM_WORKER_FILE = '';
-
 // name of the file containing the Audio Worklet *.aw.js, if relevant
 var AUDIO_WORKLET_FILE = '';
 

src/shell.js

@@ -102,6 +102,12 @@ if (ENVIRONMENT_IS_PTHREAD) {
 #endif
 #endif
 
+#if WASM_WORKERS
+// The way we signal to a worker that it is hosting a pthread is to construct
+// it with a specific name.
+var ENVIRONMENT_IS_WASM_WORKER = ENVIRONMENT_IS_WORKER && self.name?.startsWith('em-ww');
+#endif
+
 #if ENVIRONMENT_MAY_BE_NODE
 if (ENVIRONMENT_IS_NODE) {
 #if EXPORT_ES6
@@ -121,14 +127,13 @@ if (ENVIRONMENT_IS_NODE) {
   // is hosting a pthread.
   ENVIRONMENT_IS_PTHREAD = ENVIRONMENT_IS_WORKER && worker_threads['workerData'] == 'em-pthread'
 #endif // PTHREADS
+#if WASM_WORKERS
+  ENVIRONMENT_IS_WASM_WORKER = ENVIRONMENT_IS_WORKER && worker_threads['workerData'] == 'em-ww'
+#endif
 #endif // PTHREADS || WASM_WORKERS
 }
 #endif // ENVIRONMENT_MAY_BE_NODE
 
-#if WASM_WORKERS
-var ENVIRONMENT_IS_WASM_WORKER = !!Module['$ww'];
-#endif
-
 // --pre-jses are emitted after the Module integration code, so that they can
 // refer to Module (if they choose; they can also define Module)
 {{{ preJS() }}}

src/wasm_worker.js

@@ -1,12 +1,7 @@
-// N.B. The contents of this file are duplicated in src/library_wasm_worker.js
-// in variable "_wasmWorkerBlobUrl" (where the contents are pre-minified) If
-// doing any changes to this file, be sure to update the contents there too.
-
-'use strict';
+if (ENVIRONMENT_IS_WASM_WORKER) {
 
 #if ENVIRONMENT_MAY_BE_NODE
 // Node.js support
-var ENVIRONMENT_IS_NODE = typeof process == 'object' && typeof process.versions == 'object' && typeof process.versions.node == 'string' && process.type != 'renderer';
 if (ENVIRONMENT_IS_NODE) {
   // Create as web-worker-like an environment as we can.
 
@@ -28,52 +23,40 @@ if (ENVIRONMENT_IS_NODE) {
     return f;
   }
 
-  var fs = require('fs');
-  var vm = require('vm');
-
-  Object.assign(global, {
+  Object.assign(globalThis, {
     self: global,
-    require,
-#if !EXPORT_ES6
-    // `vm.runInThisContext` global scope lacks `__filename` and `__dirname`
-    __filename,
-    __dirname,
-#endif
-    Worker: nodeWorkerThreads.Worker,
-    importScripts: (f) => vm.runInThisContext(fs.readFileSync(f, 'utf8'), {filename: f}),
     postMessage: (msg) => parentPort.postMessage(msg),
-    performance: global.performance || { now: Date.now },
     addEventListener: (name, handler) => parentPort.on(name, wrapMsgHandler(handler)),
     removeEventListener: (name, handler) => parentPort.off(name, wrapMsgHandler(handler)),
   });
 }
 #endif // ENVIRONMENT_MAY_BE_NODE
 
+var wasmWorkerArgs;
+
 {{{ implicitSelf() }}}onmessage = function(d) {
   // The first message sent to the Worker is always the bootstrap message.
   // Drop this message listener, it served its purpose of bootstrapping
   // the Wasm Module load, and is no longer needed. Let user code register
   // any desired message handlers from now on.
   {{{ implicitSelf() }}}onmessage = null;
-  d = d.data;
-#if !MODULARIZE
-  self.{{{ EXPORT_NAME }}} = d;
-#endif
-#if !MINIMAL_RUNTIME
-  d['instantiateWasm'] = (info, receiveInstance) => { var instance = new WebAssembly.Instance(d['wasm'], info); return receiveInstance(instance, d['wasm']); }
+#if RUNTIME_DEBUG
+  dbg('wasm worker initial onmessage');
 #endif
-#if TRUSTED_TYPES
-  // Use Trusted Types compatible wrappers.
-  if (typeof trustedTypes != 'undefined' && trustedTypes.createPolicy) {
-    var p = trustedTypes.createPolicy('emscripten#scriptPolicy1', { createScriptURL: (ignored) => d.js });
-    importScripts(p.createScriptURL('ignored'));
-  } else
-#endif
-  importScripts(d.js);
+  d = d.data;
 #if MODULARIZE
   {{{ EXPORT_NAME }}}(d);
+#else
+  wasmWorkerArgs = d;
+  wasmMemory = d['wasmMemory'];
+  updateMemoryViews();
+#endif
+#if !MINIMAL_RUNTIME
+  wasmModuleReceived(d['wasm']);
 #endif
   // Drop now unneeded references to from the Module object in this Worker,
   // these are not needed anymore.
-  d.wasm = d.mem = d.js = 0;
+  d.wasm = d.mem = 0;
+}
+
 }