diff --git a/ChangeLog.md b/ChangeLog.md
index 39938f12e5a7a..c38e5207ea6f1 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -23,6 +23,9 @@ See docs/process.md for more on how version tagging works.
 - The file system was updated to independently track atime, mtime and ctime
   instead of using the same time for all three. (#22998)
 - The minimum supported chrome version was bumped from 32 to 33. (#23077)
+- Emscripten-generated code will now use async/await internally when loading
+  the Wasm module.  This will be lowered away by babel when targeting older
+  browsers. (#23068)
 
 3.1.73 - 11/28/24
 -----------------
diff --git a/src/preamble.js b/src/preamble.js
index af274a7ac888f..d097c857f89be 100644
--- a/src/preamble.js
+++ b/src/preamble.js
@@ -647,7 +647,7 @@ function getBinarySync(file) {
 #endif
 }
 
-function getBinaryPromise(binaryFile) {
+async function getWasmBinary(binaryFile) {
 #if !SINGLE_FILE
   // If we don't have the binary yet, load it asynchronously using readAsync.
   if (!wasmBinary
@@ -656,16 +656,17 @@ function getBinaryPromise(binaryFile) {
 #endif
       ) {
     // Fetch the binary using readAsync
-    return readAsync(binaryFile).then(
-      (response) => new Uint8Array(/** @type{!ArrayBuffer} */(response)),
-      // Fall back to getBinarySync if readAsync fails
-      () => getBinarySync(binaryFile)
-    );
+    try {
+      var response = await readAsync(binaryFile);
+      return new Uint8Array(response);
+    } catch {
+      // Fall back to getBinarySync below;
+    }
   }
 #endif
 
   // Otherwise, getBinarySync should be able to get it synchronously
-  return Promise.resolve(getBinarySync(binaryFile));
+  return getBinarySync(binaryFile);
 }
 
 #if LOAD_SOURCE_MAP
@@ -773,56 +774,47 @@ function resetPrototype(constructor, attrs) {
 #endif
 
 #if WASM_ASYNC_COMPILATION
-function instantiateArrayBuffer(binaryFile, imports) {
+async function instantiateArrayBuffer(binaryFile, imports) {
+  try {
+    var binary = await getWasmBinary(binaryFile);
+    var instance = await WebAssembly.instantiate(binary, imports);
 #if USE_OFFSET_CONVERTER
-  var savedBinary;
+    // wasmOffsetConverter needs to be assigned before calling resolve.
+    // See comments below in instantiateAsync.
+    wasmOffsetConverter = new WasmOffsetConverter(binary, instance.module);
 #endif
-  return new Promise((resolve, reject) => {
-    getBinaryPromise(binaryFile).then((binary) => {
-#if USE_OFFSET_CONVERTER
-      savedBinary = binary;
-#endif
-      return WebAssembly.instantiate(binary, imports);
-#if USE_OFFSET_CONVERTER
-    }).then((instance) => {
-      // wasmOffsetConverter needs to be assigned before calling resolve.
-      // See comments below in instantiateAsync.
-      wasmOffsetConverter = new WasmOffsetConverter(savedBinary, instance.module);
-      return instance;
-#endif
-    }).then(resolve, (reason) => {
-      err(`failed to asynchronously prepare wasm: ${reason}`);
-
+    return instance;
+  } catch (reason) {
+    err(`failed to asynchronously prepare wasm: ${reason}`);
 #if WASM == 2
 #if ENVIRONMENT_MAY_BE_NODE || ENVIRONMENT_MAY_BE_SHELL
-      if (typeof location != 'undefined') {
-#endif
-        // WebAssembly compilation failed, try running the JS fallback instead.
-        var search = location.search;
-        if (search.indexOf('_rwasm=0') < 0) {
-          location.href += (search ? search + '&' : '?') + '_rwasm=0';
-          // Return here to avoid calling abort() below.  The application
-          // still has a chance to start successfully do we don't want to
-          // trigger onAbort or onExit handlers.
-          return;
-        }
-#if ENVIRONMENT_MAY_BE_NODE || ENVIRONMENT_MAY_BE_SHELL
+    if (typeof location != 'undefined') {
+#endif
+      // WebAssembly compilation failed, try running the JS fallback instead.
+      var search = location.search;
+      if (search.indexOf('_rwasm=0') < 0) {
+        // Reload the page with the `_rwasm=0` argument
+        location.href += (search ? search + '&' : '?') + '_rwasm=0';
+        // Return a promise that never resolves.  We don't want to
+        // call abort below, or return an error to our caller.
+        return new Promise(() => {});
       }
+#if ENVIRONMENT_MAY_BE_NODE || ENVIRONMENT_MAY_BE_SHELL
+    }
 #endif
 #endif // WASM == 2
 
 #if ASSERTIONS
-      // Warn on some common problems.
-      if (isFileURI(wasmBinaryFile)) {
-        err(`warning: Loading from a file URI (${wasmBinaryFile}) is not supported in most browsers. See https://emscripten.org/docs/getting_started/FAQ.html#how-do-i-run-a-local-webserver-for-testing-why-does-my-program-stall-in-downloading-or-preparing`);
-      }
+    // Warn on some common problems.
+    if (isFileURI(wasmBinaryFile)) {
+      err(`warning: Loading from a file URI (${wasmBinaryFile}) is not supported in most browsers. See https://emscripten.org/docs/getting_started/FAQ.html#how-do-i-run-a-local-webserver-for-testing-why-does-my-program-stall-in-downloading-or-preparing`);
+    }
 #endif
-      abort(reason);
-    });
-  });
+    abort(reason);
+  }
 }
 
-function instantiateAsync(binary, binaryFile, imports) {
+async function instantiateAsync(binary, binaryFile, imports) {
 #if !SINGLE_FILE
   if (!binary &&
       typeof WebAssembly.instantiateStreaming == 'function' &&
@@ -841,56 +833,41 @@ function instantiateAsync(binary, binaryFile, imports) {
       !ENVIRONMENT_IS_NODE &&
 #endif
       typeof fetch == 'function') {
-    return new Promise((resolve) => {
-      fetch(binaryFile, {{{ makeModuleReceiveExpr('fetchSettings', "{ credentials: 'same-origin' }") }}}).then((response) => {
-        // Suppress closure warning here since the upstream definition for
-        // instantiateStreaming only allows Promise<Repsponse> rather than
-        // an actual Response.
-        // TODO(https://github.com/google/closure-compiler/pull/3913): Remove if/when upstream closure is fixed.
-        /** @suppress {checkTypes} */
-        var result = WebAssembly.instantiateStreaming(response, imports);
-
+    try {
+      var response = fetch(binaryFile, {{{ makeModuleReceiveExpr('fetchSettings', "{ credentials: 'same-origin' }") }}});
 #if USE_OFFSET_CONVERTER
-        // We need the wasm binary for the offset converter. Clone the response
-        // in order to get its arrayBuffer (cloning should be more efficient
-        // than doing another entire request).
-        // (We must clone the response now in order to use it later, as if we
-        // try to clone it asynchronously lower down then we will get a
-        // "response was already consumed" error.)
-        var clonedResponsePromise = response.clone().arrayBuffer();
-#endif
-
-        result.then(
+      // We need the wasm binary for the offset converter. Clone the response
+      // in order to get its arrayBuffer (cloning should be more efficient
+      // than doing another entire request).
+      // (We must clone the response now in order to use it later, as if we
+      // try to clone it asynchronously lower down then we will get a
+      // "response was already consumed" error.)
+      var clonedResponse = (await response).clone();
+#endif
+      var instantiationResult = await WebAssembly.instantiateStreaming(response, imports);
 #if USE_OFFSET_CONVERTER
-          (instantiationResult) => {
-            // When using the offset converter, we must interpose here. First,
-            // the instantiation result must arrive (if it fails, the error
-            // handling later down will handle it). Once it arrives, we can
-            // initialize the offset converter. And only then is it valid to
-            // call receiveInstantiationResult, as that function will use the
-            // offset converter (in the case of pthreads, it will create the
-            // pthreads and send them the offsets along with the wasm instance).
-
-            clonedResponsePromise.then((arrayBufferResult) => {
-                wasmOffsetConverter = new WasmOffsetConverter(new Uint8Array(arrayBufferResult), instantiationResult.module);
-                resolve(instantiationResult);
-              },
-              (reason) => err(`failed to initialize offset-converter: ${reason}`)
-            );
-          },
-#else
-          resolve,
-#endif
-          (reason) => {
-            // We expect the most common failure cause to be a bad MIME type for the binary,
-            // in which case falling back to ArrayBuffer instantiation should work.
-            err(`wasm streaming compile failed: ${reason}`);
-            err('falling back to ArrayBuffer instantiation');
-            return resolve(instantiateArrayBuffer(binaryFile, imports));
-          }
-        );
-      });
-    });
+      // When using the offset converter, we must interpose here. First,
+      // the instantiation result must arrive (if it fails, the error
+      // handling later down will handle it). Once it arrives, we can
+      // initialize the offset converter. And only then is it valid to
+      // call receiveInstantiationResult, as that function will use the
+      // offset converter (in the case of pthreads, it will create the
+      // pthreads and send them the offsets along with the wasm instance).
+      var arrayBufferResult = await clonedResponse.arrayBuffer();
+      try {
+        wasmOffsetConverter = new WasmOffsetConverter(new Uint8Array(arrayBufferResult), instantiationResult.module);
+      } catch (reason) {
+        err(`failed to initialize offset-converter: ${reason}`);
+      }
+#endif
+      return instantiationResult;
+    } catch (reason) {
+      // We expect the most common failure cause to be a bad MIME type for the binary,
+      // in which case falling back to ArrayBuffer instantiation should work.
+      err(`wasm streaming compile failed: ${reason}`);
+      err('falling back to ArrayBuffer instantiation');
+      // fall back of instantiateArrayBuffer below
+    };
   }
 #endif
   return instantiateArrayBuffer(binaryFile, imports);
@@ -936,7 +913,7 @@ function getWasmImports() {
 
 // Create the wasm instance.
 // Receives the wasm imports, returns the exports.
-function createWasm() {
+{{{ asyncIf(WASM_ASYNC_COMPILATION) }}} function createWasm() {
   // 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
@@ -1104,17 +1081,23 @@ function createWasm() {
 #if RUNTIME_DEBUG
   dbg('asynchronously preparing wasm');
 #endif
-  instantiateAsync(wasmBinary, wasmBinaryFile, info).then(receiveInstantiationResult)
 #if MODULARIZE
-  // If instantiation fails, reject the module ready promise.
-  .catch(readyPromiseReject)
+  try {
 #endif
-  ;
+    var result = await instantiateAsync(wasmBinary, wasmBinaryFile, info);
+    receiveInstantiationResult(result);
 #if LOAD_SOURCE_MAP
-  getSourceMapPromise().then(receiveSourceMapJSON);
+    receiveSourceMapJSON(await getSourceMapPromise());
 #endif
-  return {}; // no exports yet; we'll fill them in later
-#else
+    return result;
+#if MODULARIZE
+  } catch (e) {
+    // If instantiation fails, reject the module ready promise.
+    readyPromiseReject(e);
+    return;
+  }
+#endif
+#else // WASM_ASYNC_COMPILATION
   var result = instantiateSync(wasmBinaryFile, info);
 #if PTHREADS || MAIN_MODULE
   return receiveInstance(result[0], result[1]);
@@ -1124,7 +1107,7 @@ function createWasm() {
   // When the regression is fixed, we can remove this if/else.
   return receiveInstance(result[0]);
 #endif
-#endif
+#endif // WASM_ASYNC_COMPILATION
 }
 
 #if !WASM_BIGINT
diff --git a/test/other/codesize/test_codesize_cxx_ctors1.gzsize b/test/other/codesize/test_codesize_cxx_ctors1.gzsize
index 41c0b94155b12..25b558280e945 100644
--- a/test/other/codesize/test_codesize_cxx_ctors1.gzsize
+++ b/test/other/codesize/test_codesize_cxx_ctors1.gzsize
@@ -1 +1 @@
-8592
+8576
diff --git a/test/other/codesize/test_codesize_cxx_ctors1.jssize b/test/other/codesize/test_codesize_cxx_ctors1.jssize
index f411f89f35087..f0d741b18ae22 100644
--- a/test/other/codesize/test_codesize_cxx_ctors1.jssize
+++ b/test/other/codesize/test_codesize_cxx_ctors1.jssize
@@ -1 +1 @@
-21002
+20969
diff --git a/test/other/codesize/test_codesize_cxx_ctors2.gzsize b/test/other/codesize/test_codesize_cxx_ctors2.gzsize
index b6b3cc1b768f1..3ea5f236f6c35 100644
--- a/test/other/codesize/test_codesize_cxx_ctors2.gzsize
+++ b/test/other/codesize/test_codesize_cxx_ctors2.gzsize
@@ -1 +1 @@
-8578
+8560
diff --git a/test/other/codesize/test_codesize_cxx_ctors2.jssize b/test/other/codesize/test_codesize_cxx_ctors2.jssize
index f0d741b18ae22..4ef99cdd0785e 100644
--- a/test/other/codesize/test_codesize_cxx_ctors2.jssize
+++ b/test/other/codesize/test_codesize_cxx_ctors2.jssize
@@ -1 +1 @@
-20969
+20937
diff --git a/test/other/codesize/test_codesize_cxx_except.gzsize b/test/other/codesize/test_codesize_cxx_except.gzsize
index 699dbbf52f13f..0fa8352cf2331 100644
--- a/test/other/codesize/test_codesize_cxx_except.gzsize
+++ b/test/other/codesize/test_codesize_cxx_except.gzsize
@@ -1 +1 @@
-9626
+9614
diff --git a/test/other/codesize/test_codesize_cxx_except.jssize b/test/other/codesize/test_codesize_cxx_except.jssize
index 6a720ff726ff1..4a76440f1a1cc 100644
--- a/test/other/codesize/test_codesize_cxx_except.jssize
+++ b/test/other/codesize/test_codesize_cxx_except.jssize
@@ -1 +1 @@
-24845
+24814
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm.gzsize b/test/other/codesize/test_codesize_cxx_except_wasm.gzsize
index d9d8063900671..e6ab5d0c9b589 100644
--- a/test/other/codesize/test_codesize_cxx_except_wasm.gzsize
+++ b/test/other/codesize/test_codesize_cxx_except_wasm.gzsize
@@ -1 +1 @@
-8562
+8543
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm.jssize b/test/other/codesize/test_codesize_cxx_except_wasm.jssize
index b8733f59e9281..8b47153f81043 100644
--- a/test/other/codesize/test_codesize_cxx_except_wasm.jssize
+++ b/test/other/codesize/test_codesize_cxx_except_wasm.jssize
@@ -1 +1 @@
-20895
+20863
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm_exnref.gzsize b/test/other/codesize/test_codesize_cxx_except_wasm_exnref.gzsize
index d9d8063900671..e6ab5d0c9b589 100644
--- a/test/other/codesize/test_codesize_cxx_except_wasm_exnref.gzsize
+++ b/test/other/codesize/test_codesize_cxx_except_wasm_exnref.gzsize
@@ -1 +1 @@
-8562
+8543
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm_exnref.jssize b/test/other/codesize/test_codesize_cxx_except_wasm_exnref.jssize
index b8733f59e9281..8b47153f81043 100644
--- a/test/other/codesize/test_codesize_cxx_except_wasm_exnref.jssize
+++ b/test/other/codesize/test_codesize_cxx_except_wasm_exnref.jssize
@@ -1 +1 @@
-20895
+20863
diff --git a/test/other/codesize/test_codesize_cxx_lto.gzsize b/test/other/codesize/test_codesize_cxx_lto.gzsize
index 67e22b94ef20a..732a842aa12a6 100644
--- a/test/other/codesize/test_codesize_cxx_lto.gzsize
+++ b/test/other/codesize/test_codesize_cxx_lto.gzsize
@@ -1 +1 @@
-8490
+8475
diff --git a/test/other/codesize/test_codesize_cxx_lto.jssize b/test/other/codesize/test_codesize_cxx_lto.jssize
index 9ebbda6b548c9..c8b5e7421405b 100644
--- a/test/other/codesize/test_codesize_cxx_lto.jssize
+++ b/test/other/codesize/test_codesize_cxx_lto.jssize
@@ -1 +1 @@
-20580
+20548
diff --git a/test/other/codesize/test_codesize_cxx_mangle.gzsize b/test/other/codesize/test_codesize_cxx_mangle.gzsize
index 4dda8754d31a0..58e0f00ae02c8 100644
--- a/test/other/codesize/test_codesize_cxx_mangle.gzsize
+++ b/test/other/codesize/test_codesize_cxx_mangle.gzsize
@@ -1 +1 @@
-9629
+9613
diff --git a/test/other/codesize/test_codesize_cxx_mangle.jssize b/test/other/codesize/test_codesize_cxx_mangle.jssize
index 6a720ff726ff1..4a76440f1a1cc 100644
--- a/test/other/codesize/test_codesize_cxx_mangle.jssize
+++ b/test/other/codesize/test_codesize_cxx_mangle.jssize
@@ -1 +1 @@
-24845
+24814
diff --git a/test/other/codesize/test_codesize_cxx_noexcept.gzsize b/test/other/codesize/test_codesize_cxx_noexcept.gzsize
index 41c0b94155b12..25b558280e945 100644
--- a/test/other/codesize/test_codesize_cxx_noexcept.gzsize
+++ b/test/other/codesize/test_codesize_cxx_noexcept.gzsize
@@ -1 +1 @@
-8592
+8576
diff --git a/test/other/codesize/test_codesize_cxx_noexcept.jssize b/test/other/codesize/test_codesize_cxx_noexcept.jssize
index f411f89f35087..f0d741b18ae22 100644
--- a/test/other/codesize/test_codesize_cxx_noexcept.jssize
+++ b/test/other/codesize/test_codesize_cxx_noexcept.jssize
@@ -1 +1 @@
-21002
+20969
diff --git a/test/other/codesize/test_codesize_cxx_wasmfs.gzsize b/test/other/codesize/test_codesize_cxx_wasmfs.gzsize
index d8d3e7a082033..24a12a49287ba 100644
--- a/test/other/codesize/test_codesize_cxx_wasmfs.gzsize
+++ b/test/other/codesize/test_codesize_cxx_wasmfs.gzsize
@@ -1 +1 @@
-3865
+3836
diff --git a/test/other/codesize/test_codesize_cxx_wasmfs.jssize b/test/other/codesize/test_codesize_cxx_wasmfs.jssize
index d870f6684df37..c4ec7c412ff1e 100644
--- a/test/other/codesize/test_codesize_cxx_wasmfs.jssize
+++ b/test/other/codesize/test_codesize_cxx_wasmfs.jssize
@@ -1 +1 @@
-8639
+8606
diff --git a/test/other/codesize/test_codesize_files_js_fs.gzsize b/test/other/codesize/test_codesize_files_js_fs.gzsize
index edc514e920e03..956717deae581 100644
--- a/test/other/codesize/test_codesize_files_js_fs.gzsize
+++ b/test/other/codesize/test_codesize_files_js_fs.gzsize
@@ -1 +1 @@
-7730
+7710
diff --git a/test/other/codesize/test_codesize_files_js_fs.jssize b/test/other/codesize/test_codesize_files_js_fs.jssize
index b88e32899034b..2314d683d7cb3 100644
--- a/test/other/codesize/test_codesize_files_js_fs.jssize
+++ b/test/other/codesize/test_codesize_files_js_fs.jssize
@@ -1 +1 @@
-18909
+18876
diff --git a/test/other/codesize/test_codesize_files_wasmfs.gzsize b/test/other/codesize/test_codesize_files_wasmfs.gzsize
index a4fe1614722ba..43a5478d767d8 100644
--- a/test/other/codesize/test_codesize_files_wasmfs.gzsize
+++ b/test/other/codesize/test_codesize_files_wasmfs.gzsize
@@ -1 +1 @@
-2941
+2915
diff --git a/test/other/codesize/test_codesize_files_wasmfs.jssize b/test/other/codesize/test_codesize_files_wasmfs.jssize
index 83aaf27e746bc..5aecb7d32517a 100644
--- a/test/other/codesize/test_codesize_files_wasmfs.jssize
+++ b/test/other/codesize/test_codesize_files_wasmfs.jssize
@@ -1 +1 @@
-6244
+6214
diff --git a/test/other/codesize/test_codesize_hello_O0.gzsize b/test/other/codesize/test_codesize_hello_O0.gzsize
index f436d64e54792..af0a7b0a886ac 100644
--- a/test/other/codesize/test_codesize_hello_O0.gzsize
+++ b/test/other/codesize/test_codesize_hello_O0.gzsize
@@ -1 +1 @@
-8043
+8034
diff --git a/test/other/codesize/test_codesize_hello_O0.jssize b/test/other/codesize/test_codesize_hello_O0.jssize
index 1f1ac91c270cf..0b07ab883de47 100644
--- a/test/other/codesize/test_codesize_hello_O0.jssize
+++ b/test/other/codesize/test_codesize_hello_O0.jssize
@@ -1 +1 @@
-21457
+21479
diff --git a/test/other/codesize/test_codesize_hello_O1.gzsize b/test/other/codesize/test_codesize_hello_O1.gzsize
index 621b7ce5342a6..ece5108dd4bce 100644
--- a/test/other/codesize/test_codesize_hello_O1.gzsize
+++ b/test/other/codesize/test_codesize_hello_O1.gzsize
@@ -1 +1 @@
-2788
+2785
diff --git a/test/other/codesize/test_codesize_hello_O1.jssize b/test/other/codesize/test_codesize_hello_O1.jssize
index 027dd3849dd58..13068939d1a42 100644
--- a/test/other/codesize/test_codesize_hello_O1.jssize
+++ b/test/other/codesize/test_codesize_hello_O1.jssize
@@ -1 +1 @@
-7021
+7004
diff --git a/test/other/codesize/test_codesize_hello_O2.gzsize b/test/other/codesize/test_codesize_hello_O2.gzsize
index 8aa001e241409..51d5790fa9f86 100644
--- a/test/other/codesize/test_codesize_hello_O2.gzsize
+++ b/test/other/codesize/test_codesize_hello_O2.gzsize
@@ -1 +1 @@
-2462
+2434
diff --git a/test/other/codesize/test_codesize_hello_O2.jssize b/test/other/codesize/test_codesize_hello_O2.jssize
index 5a3b1c0e3cc2a..032c246660549 100644
--- a/test/other/codesize/test_codesize_hello_O2.jssize
+++ b/test/other/codesize/test_codesize_hello_O2.jssize
@@ -1 +1 @@
-4984
+4955
diff --git a/test/other/codesize/test_codesize_hello_O3.gzsize b/test/other/codesize/test_codesize_hello_O3.gzsize
index 37a2cebe6b9c9..c4fdb9ba8959b 100644
--- a/test/other/codesize/test_codesize_hello_O3.gzsize
+++ b/test/other/codesize/test_codesize_hello_O3.gzsize
@@ -1 +1 @@
-2380
+2346
diff --git a/test/other/codesize/test_codesize_hello_O3.jssize b/test/other/codesize/test_codesize_hello_O3.jssize
index ddeb3cf88bf70..534d8e6bdcc90 100644
--- a/test/other/codesize/test_codesize_hello_O3.jssize
+++ b/test/other/codesize/test_codesize_hello_O3.jssize
@@ -1 +1 @@
-4830
+4802
diff --git a/test/other/codesize/test_codesize_hello_Os.gzsize b/test/other/codesize/test_codesize_hello_Os.gzsize
index 37a2cebe6b9c9..c4fdb9ba8959b 100644
--- a/test/other/codesize/test_codesize_hello_Os.gzsize
+++ b/test/other/codesize/test_codesize_hello_Os.gzsize
@@ -1 +1 @@
-2380
+2346
diff --git a/test/other/codesize/test_codesize_hello_Os.jssize b/test/other/codesize/test_codesize_hello_Os.jssize
index ddeb3cf88bf70..534d8e6bdcc90 100644
--- a/test/other/codesize/test_codesize_hello_Os.jssize
+++ b/test/other/codesize/test_codesize_hello_Os.jssize
@@ -1 +1 @@
-4830
+4802
diff --git a/test/other/codesize/test_codesize_hello_Oz.gzsize b/test/other/codesize/test_codesize_hello_Oz.gzsize
index 7d945b944dabc..ffcd151c41f04 100644
--- a/test/other/codesize/test_codesize_hello_Oz.gzsize
+++ b/test/other/codesize/test_codesize_hello_Oz.gzsize
@@ -1 +1 @@
-2359
+2328
diff --git a/test/other/codesize/test_codesize_hello_Oz.jssize b/test/other/codesize/test_codesize_hello_Oz.jssize
index f2bb280333202..9f4f637fcdccb 100644
--- a/test/other/codesize/test_codesize_hello_Oz.jssize
+++ b/test/other/codesize/test_codesize_hello_Oz.jssize
@@ -1 +1 @@
-4797
+4769
diff --git a/test/other/codesize/test_codesize_hello_dylink.gzsize b/test/other/codesize/test_codesize_hello_dylink.gzsize
index d18a1e2dd1c2e..e88f7f6787c9d 100644
--- a/test/other/codesize/test_codesize_hello_dylink.gzsize
+++ b/test/other/codesize/test_codesize_hello_dylink.gzsize
@@ -1 +1 @@
-6246
+6227
diff --git a/test/other/codesize/test_codesize_hello_dylink.jssize b/test/other/codesize/test_codesize_hello_dylink.jssize
index 99087d0d64926..a9336124ba7fb 100644
--- a/test/other/codesize/test_codesize_hello_dylink.jssize
+++ b/test/other/codesize/test_codesize_hello_dylink.jssize
@@ -1 +1 @@
-13767
+13729
diff --git a/test/other/codesize/test_codesize_hello_export_nothing.gzsize b/test/other/codesize/test_codesize_hello_export_nothing.gzsize
index 8d937ef32a302..a894381fc572f 100644
--- a/test/other/codesize/test_codesize_hello_export_nothing.gzsize
+++ b/test/other/codesize/test_codesize_hello_export_nothing.gzsize
@@ -1 +1 @@
-1736
+1721
diff --git a/test/other/codesize/test_codesize_hello_export_nothing.jssize b/test/other/codesize/test_codesize_hello_export_nothing.jssize
index bb7949a47215f..1e144d1f73aa3 100644
--- a/test/other/codesize/test_codesize_hello_export_nothing.jssize
+++ b/test/other/codesize/test_codesize_hello_export_nothing.jssize
@@ -1 +1 @@
-3687
+3662
diff --git a/test/other/codesize/test_codesize_hello_wasmfs.gzsize b/test/other/codesize/test_codesize_hello_wasmfs.gzsize
index 37a2cebe6b9c9..c4fdb9ba8959b 100644
--- a/test/other/codesize/test_codesize_hello_wasmfs.gzsize
+++ b/test/other/codesize/test_codesize_hello_wasmfs.gzsize
@@ -1 +1 @@
-2380
+2346
diff --git a/test/other/codesize/test_codesize_hello_wasmfs.jssize b/test/other/codesize/test_codesize_hello_wasmfs.jssize
index ddeb3cf88bf70..534d8e6bdcc90 100644
--- a/test/other/codesize/test_codesize_hello_wasmfs.jssize
+++ b/test/other/codesize/test_codesize_hello_wasmfs.jssize
@@ -1 +1 @@
-4830
+4802
diff --git a/test/other/codesize/test_codesize_libcxxabi_message_O3.gzsize b/test/other/codesize/test_codesize_libcxxabi_message_O3.gzsize
index a60b19c7d3e35..e37d15a094a6b 100644
--- a/test/other/codesize/test_codesize_libcxxabi_message_O3.gzsize
+++ b/test/other/codesize/test_codesize_libcxxabi_message_O3.gzsize
@@ -1 +1 @@
-1942
+1920
diff --git a/test/other/codesize/test_codesize_libcxxabi_message_O3.jssize b/test/other/codesize/test_codesize_libcxxabi_message_O3.jssize
index 8fd7a8244755f..19e6874d5c5ec 100644
--- a/test/other/codesize/test_codesize_libcxxabi_message_O3.jssize
+++ b/test/other/codesize/test_codesize_libcxxabi_message_O3.jssize
@@ -1 +1 @@
-4064
+4040
diff --git a/test/other/codesize/test_codesize_libcxxabi_message_O3_standalone.gzsize b/test/other/codesize/test_codesize_libcxxabi_message_O3_standalone.gzsize
index 144764295069b..b22803ae9b835 100644
--- a/test/other/codesize/test_codesize_libcxxabi_message_O3_standalone.gzsize
+++ b/test/other/codesize/test_codesize_libcxxabi_message_O3_standalone.gzsize
@@ -1 +1 @@
-1976
+1957
diff --git a/test/other/codesize/test_codesize_libcxxabi_message_O3_standalone.jssize b/test/other/codesize/test_codesize_libcxxabi_message_O3_standalone.jssize
index aff4d86fafce6..64c1a80470aad 100644
--- a/test/other/codesize/test_codesize_libcxxabi_message_O3_standalone.jssize
+++ b/test/other/codesize/test_codesize_libcxxabi_message_O3_standalone.jssize
@@ -1 +1 @@
-4111
+4087
diff --git a/test/other/codesize/test_codesize_mem_O3.gzsize b/test/other/codesize/test_codesize_mem_O3.gzsize
index 8c88d58d59dbc..37a2cebe6b9c9 100644
--- a/test/other/codesize/test_codesize_mem_O3.gzsize
+++ b/test/other/codesize/test_codesize_mem_O3.gzsize
@@ -1 +1 @@
-2399
+2380
diff --git a/test/other/codesize/test_codesize_mem_O3.jssize b/test/other/codesize/test_codesize_mem_O3.jssize
index ce43cdbca097f..f32a182f1e944 100644
--- a/test/other/codesize/test_codesize_mem_O3.jssize
+++ b/test/other/codesize/test_codesize_mem_O3.jssize
@@ -1 +1 @@
-4973
+4943
diff --git a/test/other/codesize/test_codesize_mem_O3_grow.gzsize b/test/other/codesize/test_codesize_mem_O3_grow.gzsize
index fe534adb03b4b..13c8e99a99bbb 100644
--- a/test/other/codesize/test_codesize_mem_O3_grow.gzsize
+++ b/test/other/codesize/test_codesize_mem_O3_grow.gzsize
@@ -1 +1 @@
-2543
+2529
diff --git a/test/other/codesize/test_codesize_mem_O3_grow.jssize b/test/other/codesize/test_codesize_mem_O3_grow.jssize
index 651ba07e2d020..c016a774c8a64 100644
--- a/test/other/codesize/test_codesize_mem_O3_grow.jssize
+++ b/test/other/codesize/test_codesize_mem_O3_grow.jssize
@@ -1 +1 @@
-5254
+5228
diff --git a/test/other/codesize/test_codesize_mem_O3_grow_standalone.gzsize b/test/other/codesize/test_codesize_mem_O3_grow_standalone.gzsize
index 137c70ae46487..e60a9452f5c52 100644
--- a/test/other/codesize/test_codesize_mem_O3_grow_standalone.gzsize
+++ b/test/other/codesize/test_codesize_mem_O3_grow_standalone.gzsize
@@ -1 +1 @@
-2239
+2225
diff --git a/test/other/codesize/test_codesize_mem_O3_grow_standalone.jssize b/test/other/codesize/test_codesize_mem_O3_grow_standalone.jssize
index a42fbf5bc5e93..b02620cff6eb4 100644
--- a/test/other/codesize/test_codesize_mem_O3_grow_standalone.jssize
+++ b/test/other/codesize/test_codesize_mem_O3_grow_standalone.jssize
@@ -1 +1 @@
-4663
+4636
diff --git a/test/other/codesize/test_codesize_mem_O3_standalone.gzsize b/test/other/codesize/test_codesize_mem_O3_standalone.gzsize
index b17e4bdb15f56..0ed0ea4a170d1 100644
--- a/test/other/codesize/test_codesize_mem_O3_standalone.gzsize
+++ b/test/other/codesize/test_codesize_mem_O3_standalone.gzsize
@@ -1 +1 @@
-2208
+2190
diff --git a/test/other/codesize/test_codesize_mem_O3_standalone.jssize b/test/other/codesize/test_codesize_mem_O3_standalone.jssize
index b2b760360bf47..835fe1beea0f2 100644
--- a/test/other/codesize/test_codesize_mem_O3_standalone.jssize
+++ b/test/other/codesize/test_codesize_mem_O3_standalone.jssize
@@ -1 +1 @@
-4593
+4566
diff --git a/test/other/codesize/test_codesize_mem_O3_standalone_lib.gzsize b/test/other/codesize/test_codesize_mem_O3_standalone_lib.gzsize
index adf4269e68338..6e371fb2389ae 100644
--- a/test/other/codesize/test_codesize_mem_O3_standalone_lib.gzsize
+++ b/test/other/codesize/test_codesize_mem_O3_standalone_lib.gzsize
@@ -1 +1 @@
-1960
+1944
diff --git a/test/other/codesize/test_codesize_mem_O3_standalone_lib.jssize b/test/other/codesize/test_codesize_mem_O3_standalone_lib.jssize
index 5535a4d07c950..64c1a80470aad 100644
--- a/test/other/codesize/test_codesize_mem_O3_standalone_lib.jssize
+++ b/test/other/codesize/test_codesize_mem_O3_standalone_lib.jssize
@@ -1 +1 @@
-4115
+4087
diff --git a/test/other/codesize/test_codesize_mem_O3_standalone_narg.gzsize b/test/other/codesize/test_codesize_mem_O3_standalone_narg.gzsize
index 144764295069b..b22803ae9b835 100644
--- a/test/other/codesize/test_codesize_mem_O3_standalone_narg.gzsize
+++ b/test/other/codesize/test_codesize_mem_O3_standalone_narg.gzsize
@@ -1 +1 @@
-1976
+1957
diff --git a/test/other/codesize/test_codesize_mem_O3_standalone_narg.jssize b/test/other/codesize/test_codesize_mem_O3_standalone_narg.jssize
index aff4d86fafce6..64c1a80470aad 100644
--- a/test/other/codesize/test_codesize_mem_O3_standalone_narg.jssize
+++ b/test/other/codesize/test_codesize_mem_O3_standalone_narg.jssize
@@ -1 +1 @@
-4111
+4087
diff --git a/test/other/codesize/test_codesize_mem_O3_standalone_narg_flto.gzsize b/test/other/codesize/test_codesize_mem_O3_standalone_narg_flto.gzsize
index 144764295069b..b22803ae9b835 100644
--- a/test/other/codesize/test_codesize_mem_O3_standalone_narg_flto.gzsize
+++ b/test/other/codesize/test_codesize_mem_O3_standalone_narg_flto.gzsize
@@ -1 +1 @@
-1976
+1957
diff --git a/test/other/codesize/test_codesize_mem_O3_standalone_narg_flto.jssize b/test/other/codesize/test_codesize_mem_O3_standalone_narg_flto.jssize
index aff4d86fafce6..64c1a80470aad 100644
--- a/test/other/codesize/test_codesize_mem_O3_standalone_narg_flto.jssize
+++ b/test/other/codesize/test_codesize_mem_O3_standalone_narg_flto.jssize
@@ -1 +1 @@
-4111
+4087
diff --git a/test/other/codesize/test_codesize_minimal_64.gzsize b/test/other/codesize/test_codesize_minimal_64.gzsize
index 131de0bdc4713..3591ec6784c2f 100644
--- a/test/other/codesize/test_codesize_minimal_64.gzsize
+++ b/test/other/codesize/test_codesize_minimal_64.gzsize
@@ -1 +1 @@
-1499
+1492
diff --git a/test/other/codesize/test_codesize_minimal_64.jssize b/test/other/codesize/test_codesize_minimal_64.jssize
index 518ea7fd5d661..b2858f3749035 100644
--- a/test/other/codesize/test_codesize_minimal_64.jssize
+++ b/test/other/codesize/test_codesize_minimal_64.jssize
@@ -1 +1 @@
-3143
+3142
diff --git a/test/other/codesize/test_codesize_minimal_O0.gzsize b/test/other/codesize/test_codesize_minimal_O0.gzsize
index 26d97f396bfab..bde5b49b5d9d5 100644
--- a/test/other/codesize/test_codesize_minimal_O0.gzsize
+++ b/test/other/codesize/test_codesize_minimal_O0.gzsize
@@ -1 +1 @@
-6571
+6567
diff --git a/test/other/codesize/test_codesize_minimal_O0.jssize b/test/other/codesize/test_codesize_minimal_O0.jssize
index 4705c7d0c2aad..17bded2757b92 100644
--- a/test/other/codesize/test_codesize_minimal_O0.jssize
+++ b/test/other/codesize/test_codesize_minimal_O0.jssize
@@ -1 +1 @@
-17606
+17513
diff --git a/test/other/codesize/test_codesize_minimal_O1.gzsize b/test/other/codesize/test_codesize_minimal_O1.gzsize
index 6fcfa77a477e8..1c631e1e4ce7e 100644
--- a/test/other/codesize/test_codesize_minimal_O1.gzsize
+++ b/test/other/codesize/test_codesize_minimal_O1.gzsize
@@ -1 +1 @@
-1574
+1568
diff --git a/test/other/codesize/test_codesize_minimal_O1.jssize b/test/other/codesize/test_codesize_minimal_O1.jssize
index e4ab713200d2c..c73c83400cc5d 100644
--- a/test/other/codesize/test_codesize_minimal_O1.jssize
+++ b/test/other/codesize/test_codesize_minimal_O1.jssize
@@ -1 +1 @@
-3739
+3669
diff --git a/test/other/codesize/test_codesize_minimal_O2.gzsize b/test/other/codesize/test_codesize_minimal_O2.gzsize
index b322e68302d81..4e6ee1e5ffb6e 100644
--- a/test/other/codesize/test_codesize_minimal_O2.gzsize
+++ b/test/other/codesize/test_codesize_minimal_O2.gzsize
@@ -1 +1 @@
-1427
+1421
diff --git a/test/other/codesize/test_codesize_minimal_O2.jssize b/test/other/codesize/test_codesize_minimal_O2.jssize
index f36482a747146..b36a2e0278445 100644
--- a/test/other/codesize/test_codesize_minimal_O2.jssize
+++ b/test/other/codesize/test_codesize_minimal_O2.jssize
@@ -1 +1 @@
-2848
+2847
diff --git a/test/other/codesize/test_codesize_minimal_O3.gzsize b/test/other/codesize/test_codesize_minimal_O3.gzsize
index f252370658e8f..1aca63ba8cd53 100644
--- a/test/other/codesize/test_codesize_minimal_O3.gzsize
+++ b/test/other/codesize/test_codesize_minimal_O3.gzsize
@@ -1 +1 @@
-1393
+1386
diff --git a/test/other/codesize/test_codesize_minimal_O3.jssize b/test/other/codesize/test_codesize_minimal_O3.jssize
index 3327d2792ed58..9ddd587ee7d83 100644
--- a/test/other/codesize/test_codesize_minimal_O3.jssize
+++ b/test/other/codesize/test_codesize_minimal_O3.jssize
@@ -1 +1 @@
-2798
+2797
diff --git a/test/other/codesize/test_codesize_minimal_Os.gzsize b/test/other/codesize/test_codesize_minimal_Os.gzsize
index f252370658e8f..1aca63ba8cd53 100644
--- a/test/other/codesize/test_codesize_minimal_Os.gzsize
+++ b/test/other/codesize/test_codesize_minimal_Os.gzsize
@@ -1 +1 @@
-1393
+1386
diff --git a/test/other/codesize/test_codesize_minimal_Os.jssize b/test/other/codesize/test_codesize_minimal_Os.jssize
index 3327d2792ed58..9ddd587ee7d83 100644
--- a/test/other/codesize/test_codesize_minimal_Os.jssize
+++ b/test/other/codesize/test_codesize_minimal_Os.jssize
@@ -1 +1 @@
-2798
+2797
diff --git a/test/other/codesize/test_codesize_minimal_Oz-ctors.gzsize b/test/other/codesize/test_codesize_minimal_Oz-ctors.gzsize
index a9b14017bfece..30ed602b91565 100644
--- a/test/other/codesize/test_codesize_minimal_Oz-ctors.gzsize
+++ b/test/other/codesize/test_codesize_minimal_Oz-ctors.gzsize
@@ -1 +1 @@
-1383
+1378
diff --git a/test/other/codesize/test_codesize_minimal_Oz-ctors.jssize b/test/other/codesize/test_codesize_minimal_Oz-ctors.jssize
index 7ab19b5b480cf..baa5fd743de19 100644
--- a/test/other/codesize/test_codesize_minimal_Oz-ctors.jssize
+++ b/test/other/codesize/test_codesize_minimal_Oz-ctors.jssize
@@ -1 +1 @@
-2783
+2782
diff --git a/test/other/codesize/test_codesize_minimal_Oz.gzsize b/test/other/codesize/test_codesize_minimal_Oz.gzsize
index f252370658e8f..1aca63ba8cd53 100644
--- a/test/other/codesize/test_codesize_minimal_Oz.gzsize
+++ b/test/other/codesize/test_codesize_minimal_Oz.gzsize
@@ -1 +1 @@
-1393
+1386
diff --git a/test/other/codesize/test_codesize_minimal_Oz.jssize b/test/other/codesize/test_codesize_minimal_Oz.jssize
index 3327d2792ed58..9ddd587ee7d83 100644
--- a/test/other/codesize/test_codesize_minimal_Oz.jssize
+++ b/test/other/codesize/test_codesize_minimal_Oz.jssize
@@ -1 +1 @@
-2798
+2797
diff --git a/test/other/codesize/test_codesize_minimal_pthreads.gzsize b/test/other/codesize/test_codesize_minimal_pthreads.gzsize
index a4ca075180c97..7223c3c378623 100644
--- a/test/other/codesize/test_codesize_minimal_pthreads.gzsize
+++ b/test/other/codesize/test_codesize_minimal_pthreads.gzsize
@@ -1 +1 @@
-4188
+4177
diff --git a/test/other/codesize/test_codesize_minimal_pthreads.jssize b/test/other/codesize/test_codesize_minimal_pthreads.jssize
index 179d18debb431..b26b806a10c6c 100644
--- a/test/other/codesize/test_codesize_minimal_pthreads.jssize
+++ b/test/other/codesize/test_codesize_minimal_pthreads.jssize
@@ -1 +1 @@
-8667
+8656
diff --git a/test/other/codesize/test_codesize_minimal_wasmfs.gzsize b/test/other/codesize/test_codesize_minimal_wasmfs.gzsize
index f252370658e8f..1aca63ba8cd53 100644
--- a/test/other/codesize/test_codesize_minimal_wasmfs.gzsize
+++ b/test/other/codesize/test_codesize_minimal_wasmfs.gzsize
@@ -1 +1 @@
-1393
+1386
diff --git a/test/other/codesize/test_codesize_minimal_wasmfs.jssize b/test/other/codesize/test_codesize_minimal_wasmfs.jssize
index 3327d2792ed58..9ddd587ee7d83 100644
--- a/test/other/codesize/test_codesize_minimal_wasmfs.jssize
+++ b/test/other/codesize/test_codesize_minimal_wasmfs.jssize
@@ -1 +1 @@
-2798
+2797
diff --git a/test/other/test_unoptimized_code_size.js.size b/test/other/test_unoptimized_code_size.js.size
index 48f4d8dcae999..ba18cec99cb25 100644
--- a/test/other/test_unoptimized_code_size.js.size
+++ b/test/other/test_unoptimized_code_size.js.size
@@ -1 +1 @@
-54928
+54390
diff --git a/test/other/test_unoptimized_code_size_no_asserts.js.size b/test/other/test_unoptimized_code_size_no_asserts.js.size
index cec4a3ebfe845..921d6b46a36b7 100644
--- a/test/other/test_unoptimized_code_size_no_asserts.js.size
+++ b/test/other/test_unoptimized_code_size_no_asserts.js.size
@@ -1 +1 @@
-30416
+29886
diff --git a/test/other/test_unoptimized_code_size_strict.js.size b/test/other/test_unoptimized_code_size_strict.js.size
index 5c3cf64221739..f49c2da41fbc0 100644
--- a/test/other/test_unoptimized_code_size_strict.js.size
+++ b/test/other/test_unoptimized_code_size_strict.js.size
@@ -1 +1 @@
-53724
+53186
diff --git a/test/test_browser.py b/test/test_browser.py
index 91521d09db869..0e8d7edee8a93 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -5519,7 +5519,7 @@ def test(args, expect_fail):
       if expect_fail:
         js = read_file('a.out.js')
         create_file('a.out.js', 'let origFetch = fetch; fetch = undefined;\n' + js)
-        return self.run_browser('a.out.html', '/report_result?exception:fetch is not a function')
+        return self.run_browser('a.out.html', '/report_result?abort:both async and sync fetching of the wasm failed')
       else:
         return self.run_browser('a.out.html', '/report_result?exit:42')
 
diff --git a/test/test_other.py b/test/test_other.py
index dd46dd1df2569..f3e6b7ee59b9a 100644
--- a/test/test_other.py
+++ b/test/test_other.py
@@ -2955,20 +2955,25 @@ def test_m_mm(self):
       self.assertNotContained('error', proc.stderr)
 
   @uses_canonical_tmp
-  def test_emcc_debug_files(self):
-    for opts in (0, 1, 2, 3):
-      for debug in (None, '1', '2'):
-        print(opts, debug)
-        if os.path.exists(self.canonical_temp_dir):
-          shutil.rmtree(self.canonical_temp_dir)
-
-        with env_modify({'EMCC_DEBUG': debug}):
-          self.run_process([EMCC, test_file('hello_world.c'), '-O' + str(opts)], stderr=PIPE)
-          if debug is None:
-            self.assertFalse(os.path.exists(self.canonical_temp_dir))
-          else:
-            print(sorted(os.listdir(self.canonical_temp_dir)))
-            self.assertExists(os.path.join(self.canonical_temp_dir, 'emcc-03-original.js'))
+  @parameterized({
+    'O0': ('-O0',),
+    'O1': ('-O1',),
+    'O2': ('-O2',),
+    'O3': ('-O3',),
+  })
+  def test_emcc_debug_files(self, opt):
+    for debug in (None, '1', '2'):
+      print('debug =', debug)
+      if os.path.exists(self.canonical_temp_dir):
+        shutil.rmtree(self.canonical_temp_dir)
+
+      with env_modify({'EMCC_DEBUG': debug}):
+        self.run_process([EMCC, test_file('hello_world.c'), opt], stderr=PIPE)
+        if debug is None:
+          self.assertFalse(os.path.exists(self.canonical_temp_dir))
+        else:
+          print(sorted(os.listdir(self.canonical_temp_dir)))
+          self.assertExists(os.path.join(self.canonical_temp_dir, 'emcc-03-original.js'))
 
   def test_debuginfo_line_tables_only(self):
     def test(do_compile):
diff --git a/tools/emscripten.py b/tools/emscripten.py
index 65584d17e0144..c2d36561d7776 100644
--- a/tools/emscripten.py
+++ b/tools/emscripten.py
@@ -989,7 +989,10 @@ def create_module(receiving, metadata, global_exports, library_symbols):
     module.append('var wasmImports = %s;\n' % sending)
 
   if not settings.MINIMAL_RUNTIME:
-    module.append("var wasmExports = createWasm();\n")
+    if settings.WASM_ASYNC_COMPILATION:
+      module.append("var wasmExports;\ncreateWasm();\n")
+    else:
+      module.append("var wasmExports = createWasm();\n")
 
   module.append(receiving)
   if settings.SUPPORT_LONGJMP == 'emscripten' or not settings.DISABLE_EXCEPTION_CATCHING: