From c14c1a95b060ca9112bd293ea199f6422aeb1837 Mon Sep 17 00:00:00 2001
From: Sam Clegg <sbc@chromium.org>
Date: Fri, 11 Oct 2024 10:20:48 -0700
Subject: [PATCH 1/2] Error on wasm worker creation when SAB is not available

This should have been part of #22710
---
 src/library_wasm_worker.js                 | 7 ++++++-
 test/code_size/hello_wasm_worker_wasm.js   | 1 +
 test/code_size/hello_wasm_worker_wasm.json | 8 ++++----
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/library_wasm_worker.js b/src/library_wasm_worker.js
index ec50bdb1f8df0..c73cfd05e934e 100644
--- a/src/library_wasm_worker.js
+++ b/src/library_wasm_worker.js
@@ -137,7 +137,6 @@ addToLibrary({
   // 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', '$_wasmWorkerRunPostMessage',
@@ -156,6 +155,12 @@ if (ENVIRONMENT_IS_WASM_WORKER
   addEventListener("message", _wasmWorkerAppendToQueue);
 }`,
   _emscripten_create_wasm_worker: (stackLowestAddress, stackSize) => {
+    if (typeof SharedArrayBuffer == 'undefined') {
+#if ASSERTIONS
+      dbg('create_wasm_worker: environment does not support SharedArrayBuffer, wasm workers are not available');
+#endif
+      return 0;
+    }
     let worker = _wasmWorkers[_wasmWorkersID] = new Worker(
 #if WASM_WORKERS == 2
       // WASM_WORKERS=2 mode embeds .ww.js file contents into the main .js file
diff --git a/test/code_size/hello_wasm_worker_wasm.js b/test/code_size/hello_wasm_worker_wasm.js
index 4e7446cc3dfa6..4cfde0b3130ef 100644
--- a/test/code_size/hello_wasm_worker_wasm.js
+++ b/test/code_size/hello_wasm_worker_wasm.js
@@ -15,6 +15,7 @@ c && (m[0] = this, addEventListener("message", l));
 WebAssembly.instantiate(b.wasm, {
     a: {
         b: (a, d) => {
+            if ("undefined" == typeof SharedArrayBuffer) return 0;
             let r = m[n] = new Worker(b.$wb);
             r.postMessage({
                 $ww: n,
diff --git a/test/code_size/hello_wasm_worker_wasm.json b/test/code_size/hello_wasm_worker_wasm.json
index 8e9c264d88594..bde3b5b202084 100644
--- a/test/code_size/hello_wasm_worker_wasm.json
+++ b/test/code_size/hello_wasm_worker_wasm.json
@@ -1,12 +1,12 @@
 {
   "a.html": 618,
   "a.html.gz": 384,
-  "a.js": 665,
-  "a.js.gz": 455,
+  "a.js": 715,
+  "a.js.gz": 484,
   "a.ww.js": 115,
   "a.ww.js.gz": 127,
   "a.wasm": 1850,
   "a.wasm.gz": 1050,
-  "total": 3248,
-  "total_gz": 2016
+  "total": 3298,
+  "total_gz": 2045
 }

From e097cb694b9b2d01e3746a1ae2497cec5430e1b8 Mon Sep 17 00:00:00 2001
From: Sam Clegg <sbc@chromium.org>
Date: Fri, 11 Oct 2024 13:06:01 -0700
Subject: [PATCH 2/2] feedback

---
 src/library_wasm_worker.js                 | 9 ++++++---
 test/code_size/hello_wasm_worker_wasm.js   | 1 -
 test/code_size/hello_wasm_worker_wasm.json | 8 ++++----
 3 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/library_wasm_worker.js b/src/library_wasm_worker.js
index c73cfd05e934e..1bda126e3a211 100644
--- a/src/library_wasm_worker.js
+++ b/src/library_wasm_worker.js
@@ -142,6 +142,9 @@ addToLibrary({
     '$_wasmWorkerAppendToQueue', '$_wasmWorkerRunPostMessage',
 #if WASM_WORKERS == 2
     '$_wasmWorkerBlobUrl',
+#endif
+#if ASSERTIONS
+    'emscripten_has_threading_support',
 #endif
   ],
   _emscripten_create_wasm_worker__postset: `
@@ -155,12 +158,12 @@ if (ENVIRONMENT_IS_WASM_WORKER
   addEventListener("message", _wasmWorkerAppendToQueue);
 }`,
   _emscripten_create_wasm_worker: (stackLowestAddress, stackSize) => {
-    if (typeof SharedArrayBuffer == 'undefined') {
 #if ASSERTIONS
-      dbg('create_wasm_worker: environment does not support SharedArrayBuffer, wasm workers are not available');
-#endif
+    if (!_emscripten_has_threading_support()) {
+      err('create_wasm_worker: environment does not support SharedArrayBuffer, wasm workers are not available');
       return 0;
     }
+#endif
     let worker = _wasmWorkers[_wasmWorkersID] = new Worker(
 #if WASM_WORKERS == 2
       // WASM_WORKERS=2 mode embeds .ww.js file contents into the main .js file
diff --git a/test/code_size/hello_wasm_worker_wasm.js b/test/code_size/hello_wasm_worker_wasm.js
index 4cfde0b3130ef..4e7446cc3dfa6 100644
--- a/test/code_size/hello_wasm_worker_wasm.js
+++ b/test/code_size/hello_wasm_worker_wasm.js
@@ -15,7 +15,6 @@ c && (m[0] = this, addEventListener("message", l));
 WebAssembly.instantiate(b.wasm, {
     a: {
         b: (a, d) => {
-            if ("undefined" == typeof SharedArrayBuffer) return 0;
             let r = m[n] = new Worker(b.$wb);
             r.postMessage({
                 $ww: n,
diff --git a/test/code_size/hello_wasm_worker_wasm.json b/test/code_size/hello_wasm_worker_wasm.json
index bde3b5b202084..8e9c264d88594 100644
--- a/test/code_size/hello_wasm_worker_wasm.json
+++ b/test/code_size/hello_wasm_worker_wasm.json
@@ -1,12 +1,12 @@
 {
   "a.html": 618,
   "a.html.gz": 384,
-  "a.js": 715,
-  "a.js.gz": 484,
+  "a.js": 665,
+  "a.js.gz": 455,
   "a.ww.js": 115,
   "a.ww.js.gz": 127,
   "a.wasm": 1850,
   "a.wasm.gz": 1050,
-  "total": 3298,
-  "total_gz": 2045
+  "total": 3248,
+  "total_gz": 2016
 }