Allow minification of pthread postMessage objects. NFC (emscripten-core#22555)

In the part using unquoted key here meant that closure would minify
these key and this was a problem because the separate worker.js files
would not then be able to interpret them.

However since emscripten-core#21701 landed there is no longer separate worker.js file
so closure can minify these keys and it will effect both sending and
receiving code.

Author: sbc100

src/library_pthread.js

@@ -229,16 +229,16 @@ var LibraryPThread = {
     loadWasmModuleToWorker: (worker) => new Promise((onFinishedLoading) => {
       worker.onmessage = (e) => {
         var d = e['data'];
-        var cmd = d['cmd'];
+        var cmd = d.cmd;
 
         // If this message is intended to a recipient that is not the main
         // thread, forward it to the target thread.
-        if (d['targetThread'] && d['targetThread'] != _pthread_self()) {
-          var targetWorker = PThread.pthreads[d['targetThread']];
+        if (d.targetThread && d.targetThread != _pthread_self()) {
+          var targetWorker = PThread.pthreads[d.targetThread];
           if (targetWorker) {
-            targetWorker.postMessage(d, d['transferList']);
+            targetWorker.postMessage(d, d.transferList);
           } else {
-            err(`Internal error! Worker sent a message "${cmd}" to target pthread ${d['targetThread']}, but that thread no longer exists!`);
+            err(`Internal error! Worker sent a message "${cmd}" to target pthread ${d.targetThread}, but that thread no longer exists!`);
           }
           return;
         }
@@ -248,10 +248,10 @@ var LibraryPThread = {
         } else if (cmd === 'spawnThread') {
           spawnThread(d);
         } else if (cmd === 'cleanupThread') {
-          cleanupThread(d['thread']);
+          cleanupThread(d.thread);
 #if MAIN_MODULE
         } else if (cmd === 'markAsFinished') {
-          markAsFinished(d['thread']);
+          markAsFinished(d.thread);
 #endif
         } else if (cmd === 'loaded') {
           worker.loaded = true;
@@ -266,13 +266,13 @@ var LibraryPThread = {
 #endif
           onFinishedLoading(worker);
         } else if (cmd === 'alert') {
-          alert(`Thread ${d['threadId']}: ${d['text']}`);
+          alert(`Thread ${d.threadId}: ${d.text}`);
         } else if (d.target === 'setimmediate') {
           // Worker wants to postMessage() to itself to implement setImmediate()
           // emulation.
           worker.postMessage(d);
         } else if (cmd === 'callHandler') {
-          Module[d['handler']](...d['args']);
+          Module[d.handler](...d.args);
         } else if (cmd) {
           // The received message looks like something that should be handled by this message
           // handler, (since there is a e.data.cmd field present), but is not one of the
@@ -333,28 +333,28 @@ var LibraryPThread = {
 
       // Ask the new worker to load up the Emscripten-compiled page. This is a heavy operation.
       worker.postMessage({
-        'cmd': 'load',
-        'handlers': handlers,
+        cmd: 'load',
+        handlers: handlers,
 #if WASM2JS
         // the polyfill WebAssembly.Memory instance has function properties,
         // which will fail in postMessage, so just send a custom object with the
         // property we need, the buffer
-        'wasmMemory': { 'buffer': wasmMemory.buffer },
+        wasmMemory: { 'buffer': wasmMemory.buffer },
 #else // WASM2JS
-        'wasmMemory': wasmMemory,
+        wasmMemory,
 #endif // WASM2JS
-        'wasmModule': wasmModule,
+        wasmModule,
 #if LOAD_SOURCE_MAP
-        'wasmSourceMap': wasmSourceMap,
+        wasmSourceMap,
 #endif
 #if USE_OFFSET_CONVERTER
-        'wasmOffsetConverter': wasmOffsetConverter,
+        wasmOffsetConverter,
 #endif
 #if MAIN_MODULE
-        'dynamicLibraries': dynamicLibraries,
+        dynamicLibraries,
         // Share all modules that have been loaded so far.  New workers
         // won't start running threads until these are all loaded.
-        'sharedModules': sharedModules,
+        sharedModules,
 #endif
 #if ASSERTIONS
         'workerID': worker.workerID,
@@ -503,7 +503,7 @@ var LibraryPThread = {
     // the onmessage handlers if the message was coming from valid worker.
     worker.onmessage = (e) => {
 #if ASSERTIONS
-      var cmd = e['data']['cmd'];
+      var cmd = e['data'].cmd;
       err(`received "${cmd}" command from terminated worker: ${worker.workerID}`);
 #endif
     };
@@ -519,7 +519,7 @@ var LibraryPThread = {
     dbg(`_emscripten_thread_cleanup: ${ptrToString(thread)}`)
 #endif
     if (!ENVIRONMENT_IS_PTHREAD) cleanupThread(thread);
-    else postMessage({ 'cmd': 'cleanupThread', 'thread': thread });
+    else postMessage({ cmd: 'cleanupThread', thread });
   },
 
   _emscripten_thread_set_strongref: (thread) => {
@@ -618,10 +618,10 @@ var LibraryPThread = {
 
     worker.pthread_ptr = threadParams.pthread_ptr;
     var msg = {
-        'cmd': 'run',
-        'start_routine': threadParams.startRoutine,
-        'arg': threadParams.arg,
-        'pthread_ptr': threadParams.pthread_ptr,
+        cmd: 'run',
+        start_routine: threadParams.startRoutine,
+        arg: threadParams.arg,
+        pthread_ptr: threadParams.pthread_ptr,
     };
 #if OFFSCREENCANVAS_SUPPORT
     // Note that we do not need to quote these names because they are only used
@@ -1110,7 +1110,7 @@ var LibraryPThread = {
     // running, but remain around waiting to be joined.  In this state they
     // cannot run any more proxied work.
     if (!ENVIRONMENT_IS_PTHREAD) markAsFinished(thread);
-    else postMessage({ 'cmd': 'markAsFinished', 'thread': thread });
+    else postMessage({ cmd: 'markAsFinished', thread });
   },
 
   $markAsFinished: (pthread_ptr) => {
@@ -1242,20 +1242,20 @@ var LibraryPThread = {
   // new thread that has not had a chance to initialize itself and execute
   // Atomics.waitAsync to prepare for the notification.
   _emscripten_notify_mailbox_postmessage__deps: ['$checkMailbox'],
-  _emscripten_notify_mailbox_postmessage: (targetThreadId, currThreadId) => {
-    if (targetThreadId == currThreadId) {
+  _emscripten_notify_mailbox_postmessage: (targetThread, currThreadId) => {
+    if (targetThread == currThreadId) {
       setTimeout(checkMailbox);
     } else if (ENVIRONMENT_IS_PTHREAD) {
-      postMessage({'targetThread' : targetThreadId, 'cmd' : 'checkMailbox'});
+      postMessage({targetThread, cmd: 'checkMailbox'});
     } else {
-      var worker = PThread.pthreads[targetThreadId];
+      var worker = PThread.pthreads[targetThread];
       if (!worker) {
 #if ASSERTIONS
-        err(`Cannot send message to thread with ID ${targetThreadId}, unknown thread ID!`);
+        err(`Cannot send message to thread with ID ${targetThread}, unknown thread ID!`);
 #endif
         return;
       }
-      worker.postMessage({'cmd' : 'checkMailbox'});
+      worker.postMessage({cmd: 'checkMailbox'});
     }
   }
 };

src/runtime_pthread.js

@@ -103,10 +103,10 @@ if (ENVIRONMENT_IS_PTHREAD) {
     try {
       var msgData = e['data'];
       //dbg('msgData: ' + Object.keys(msgData));
-      var cmd = msgData['cmd'];
+      var cmd = msgData.cmd;
       if (cmd === 'load') { // Preload command that is called once per worker to parse and load the Emscripten code.
 #if ASSERTIONS
-        workerID = msgData['workerID'];
+        workerID = msgData.workerID;
 #endif
 #if PTHREADS_DEBUG
         dbg('worker: loading module')
@@ -119,7 +119,7 @@ if (ENVIRONMENT_IS_PTHREAD) {
         // And add a callback for when the runtime is initialized.
         self.startWorker = (instance) => {
           // Notify the main thread that this thread has loaded.
-          postMessage({ 'cmd': 'loaded' });
+          postMessage({ cmd: 'loaded' });
           // Process any messages that were queued before the thread was ready.
           for (let msg of messageQueue) {
             handleMessage(msg);
@@ -129,16 +129,16 @@ if (ENVIRONMENT_IS_PTHREAD) {
         };
 
 #if MAIN_MODULE
-        dynamicLibraries = msgData['dynamicLibraries'];
-        sharedModules = msgData['sharedModules'];
+        dynamicLibraries = msgData.dynamicLibraries;
+        sharedModules = msgData.sharedModules;
 #if RUNTIME_DEBUG
-        dbg(`worker: received ${Object.keys(msgData['sharedModules']).length} shared modules: ${Object.keys(msgData.sharedModules)}`);
+        dbg(`worker: received ${Object.keys(msgData.sharedModules).length} shared modules: ${Object.keys(msgData.sharedModules)}`);
 #endif
 #endif
 
         // Use `const` here to ensure that the variable is scoped only to
         // that iteration, allowing safe reference from a closure.
-        for (const handler of msgData['handlers']) {
+        for (const handler of msgData.handlers) {
           // The the main module has a handler for a certain even, but no
           // handler exists on the pthread worker, then proxy that handler
           // back to the main thread.
@@ -161,41 +161,41 @@ if (ENVIRONMENT_IS_PTHREAD) {
 #endif
         }
 
-        wasmMemory = msgData['wasmMemory'];
+        wasmMemory = msgData.wasmMemory;
         updateMemoryViews();
 
 #if LOAD_SOURCE_MAP
-        wasmSourceMap = resetPrototype(WasmSourceMap, msgData['wasmSourceMap']);
+        wasmSourceMap = resetPrototype(WasmSourceMap, msgData.wasmSourceMap);
 #endif
 #if USE_OFFSET_CONVERTER
-        wasmOffsetConverter = resetPrototype(WasmOffsetConverter, msgData['wasmOffsetConverter']);
+        wasmOffsetConverter = resetPrototype(WasmOffsetConverter, msgData.wasmOffsetConverter);
 #endif
 
 #if MINIMAL_RUNTIME
         // Pass the shared Wasm module in the Module object for MINIMAL_RUNTIME.
-        Module['wasm'] = msgData['wasmModule'];
+        Module['wasm'] = msgData.wasmModule;
         loadModule();
 #else
-        wasmPromiseResolve(msgData['wasmModule']);
+        wasmPromiseResolve(msgData.wasmModule);
 #endif // MINIMAL_RUNTIME
       } else if (cmd === 'run') {
 #if ASSERTIONS
-        assert(msgData['pthread_ptr']);
+        assert(msgData.pthread_ptr);
 #endif
         // Call inside JS module to set up the stack frame for this pthread in JS module scope.
         // This needs to be the first thing that we do, as we cannot call to any C/C++ functions
         // until the thread stack is initialized.
-        establishStackSpace(msgData['pthread_ptr']);
+        establishStackSpace(msgData.pthread_ptr);
 
         // Pass the thread address to wasm to store it for fast access.
-        __emscripten_thread_init(msgData['pthread_ptr'], /*is_main=*/0, /*is_runtime=*/0, /*can_block=*/1, 0, 0);
+        __emscripten_thread_init(msgData.pthread_ptr, /*is_main=*/0, /*is_runtime=*/0, /*can_block=*/1, 0, 0);
 
         PThread.receiveObjectTransfer(msgData);
         PThread.threadInitTLS();
 
         // Await mailbox notifications with `Atomics.waitAsync` so we can start
         // using the fast `Atomics.notify` notification path.
-        __emscripten_thread_mailbox_await(msgData['pthread_ptr']);
+        __emscripten_thread_mailbox_await(msgData.pthread_ptr);
 
         if (!initializedJS) {
 #if EMBIND
@@ -210,7 +210,7 @@ if (ENVIRONMENT_IS_PTHREAD) {
         }
 
         try {
-          invokeEntryPoint(msgData['start_routine'], msgData['arg']);
+          invokeEntryPoint(msgData.start_routine, msgData.arg);
         } catch(ex) {
           if (ex != 'unwind') {
             // The pthread "crashed".  Do not call `_emscripten_thread_exit` (which

test/other/codesize/test_codesize_minimal_pthreads.gzsize

@@ -1 +1 @@
-5012
+4959

test/other/codesize/test_codesize_minimal_pthreads.jssize

@@ -1 +1 @@
-10825
+10602