Avoid using Module.instantiateWasm for pthreads. (emscripten-core#22912)

This leave the Module.instantiateWasm API for users to overide as they
please.

Fixes: emscripten-core#22905

Author: sbc100

src/preamble.js

@@ -930,7 +930,6 @@ function getWasmImports() {
 // Create the wasm instance.
 // Receives the wasm imports, returns the exports.
 function createWasm() {
-  var info = getWasmImports();
   // Load the wasm module and create an instance of using native support in the JS engine.
   // handle a generated wasm instance, receiving its exports and
   // performing other necessary setup
@@ -1054,6 +1053,8 @@ function createWasm() {
   }
 #endif // WASM_ASYNC_COMPILATION
 
+  var info = getWasmImports();
+
 #if expectToReceiveOnModule('instantiateWasm')
   // User shell pages can write their own Module.instantiateWasm = function(imports, successCallback) callback
   // to manually instantiate the Wasm module themselves. This allows pages to
@@ -1076,6 +1077,20 @@ function createWasm() {
   }
 #endif
 
+#if PTHREADS
+  if (ENVIRONMENT_IS_PTHREAD) {
+    return new Promise((resolve) => {
+      wasmModuleReceived = (module) => {
+        // Instantiate from the module posted from the main thread.
+        // We can just use sync instantiation in the worker.
+        var instance = new WebAssembly.Instance(module, getWasmImports());
+        receiveInstance(instance, module);
+        resolve();
+      };
+    });
+  }
+#endif
+
   wasmBinaryFile ??= findWasmBinary();
 
 #if WASM_ASYNC_COMPILATION

src/runtime_pthread.js

@@ -16,7 +16,7 @@ var workerID = 0;
 
 if (ENVIRONMENT_IS_PTHREAD) {
 #if !MINIMAL_RUNTIME
-  var wasmPromiseResolve;
+  var wasmModuleReceived;
 #endif
 
 #if ENVIRONMENT_MAY_BE_NODE
@@ -62,27 +62,6 @@ if (ENVIRONMENT_IS_PTHREAD) {
   }
   self.alert = threadAlert;
 
-#if !MINIMAL_RUNTIME
-  Module['instantiateWasm'] = (info, receiveInstance) => {
-    return new Promise((resolve) => {
-      wasmPromiseResolve = (module) => {
-        // Instantiate from the module posted from the main thread.
-        // We can just use sync instantiation in the worker.
-        var instance = new WebAssembly.Instance(module, getWasmImports());
-#if RELOCATABLE || MAIN_MODULE
-        receiveInstance(instance, module);
-#else
-        // TODO: Due to Closure regression https://github.com/google/closure-compiler/issues/3193,
-        // the above line no longer optimizes out down to the following line.
-        // When the regression is fixed, we can remove this if/else.
-        receiveInstance(instance);
-#endif
-        resolve();
-      };
-    });
-  }
-#endif
-
   // Turn unhandled rejected promises into errors so that the main thread will be
   // notified about them.
   self.onunhandledrejection = (e) => { throw e.reason || e; };
@@ -164,7 +143,7 @@ if (ENVIRONMENT_IS_PTHREAD) {
         Module['wasm'] = msgData.wasmModule;
         loadModule();
 #else
-        wasmPromiseResolve(msgData.wasmModule);
+        wasmModuleReceived(msgData.wasmModule);
 #endif // MINIMAL_RUNTIME
       } else if (cmd === 'run') {
 #if ASSERTIONS

test/other/codesize/test_codesize_minimal_pthreads.gzsize

@@ -1 +1 @@
-4244
+4195

test/other/codesize/test_codesize_minimal_pthreads.jssize

@@ -1 +1 @@
-8800
+8657

tools/link.py

@@ -495,10 +495,6 @@ def setup_pthreads():
 
   default_setting('DEFAULT_PTHREAD_STACK_SIZE', settings.STACK_SIZE)
 
-  if not settings.MINIMAL_RUNTIME and 'instantiateWasm' not in settings.INCOMING_MODULE_JS_API:
-    # pthreads runtime depends on overriding instantiateWasm
-    settings.INCOMING_MODULE_JS_API.append('instantiateWasm')
-
   # Functions needs by runtime_pthread.js
   settings.REQUIRED_EXPORTS += [
     '_emscripten_thread_free_data',