lib: replace global SharedArrayBuffer constructor with bound method

Renegade334 · aduh95 · commit 33baaf42c833 · 2025-11-13T22:44:17.000+01:00
PR-URL: #60497 Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com> Reviewed-By: Shelley Vohr <shelley.vohr@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
diff --git a/lib/internal/main/worker_thread.js b/lib/internal/main/worker_thread.js
@@ -11,9 +11,6 @@ const {
   ObjectDefineProperty,
   PromisePrototypeThen,
   RegExpPrototypeExec,
-  globalThis: {
-    SharedArrayBuffer,
-  },
 } = primordials;
 
 const {
@@ -119,23 +116,21 @@ port.on('message', (message) => {
     require('internal/worker').assignEnvironmentData(environmentData);
     setupMainThreadPort(mainThreadPort);
 
-    if (SharedArrayBuffer !== undefined) {
-      // The counter is only passed to the workers created by the main thread,
-      // not to workers created by other workers.
-      let cachedCwd = '';
-      let lastCounter = -1;
-      const originalCwd = process.cwd;
-
-      process.cwd = function() {
-        const currentCounter = AtomicsLoad(cwdCounter, 0);
-        if (currentCounter === lastCounter)
-          return cachedCwd;
-        lastCounter = currentCounter;
-        cachedCwd = originalCwd();
+    // The counter is only passed to the workers created by the main thread,
+    // not to workers created by other workers.
+    let cachedCwd = '';
+    let lastCounter = -1;
+    const originalCwd = process.cwd;
+
+    process.cwd = function() {
+      const currentCounter = AtomicsLoad(cwdCounter, 0);
+      if (currentCounter === lastCounter)
         return cachedCwd;
-      };
-      workerIo.sharedCwdCounter = cwdCounter;
-    }
+      lastCounter = currentCounter;
+      cachedCwd = originalCwd();
+      return cachedCwd;
+    };
+    workerIo.sharedCwdCounter = cwdCounter;
 
     const isLoaderHookWorker = (filename === 'internal/modules/esm/worker' && doEval === 'internal');
     if (!isLoaderHookWorker) {
diff --git a/lib/internal/modules/esm/hooks.js b/lib/internal/modules/esm/hooks.js
@@ -15,13 +15,8 @@ const {
   SafeSet,
   StringPrototypeSlice,
   StringPrototypeToUpperCase,
-  globalThis,
 } = primordials;
 
-const {
-  SharedArrayBuffer,
-} = globalThis;
-
 const {
   ERR_ASYNC_LOADER_REQUEST_NEVER_SETTLED,
   ERR_INTERNAL_ASSERTION,
@@ -44,6 +39,7 @@ const {
   validateString,
 } = require('internal/validators');
 const {
+  constructSharedArrayBuffer,
   kEmptyObject,
 } = require('internal/util');
 
@@ -535,7 +531,7 @@ class AsyncLoaderHookWorker {
     const { InternalWorker } = require('internal/worker');
     MessageChannel ??= require('internal/worker/io').MessageChannel;
 
-    const lock = new SharedArrayBuffer(SHARED_MEMORY_BYTE_LENGTH);
+    const lock = constructSharedArrayBuffer(SHARED_MEMORY_BYTE_LENGTH);
     this.#lock = new Int32Array(lock);
 
     this.#worker = new InternalWorker('internal/modules/esm/worker', {
diff --git a/lib/internal/streams/fast-utf8-stream.js b/lib/internal/streams/fast-utf8-stream.js
@@ -9,13 +9,14 @@ const {
   AtomicsWait,
   Int32Array,
   MathMax,
+  Number,
   SymbolDispose,
-  globalThis: {
-    Number,
-    SharedArrayBuffer,
-  },
 } = primordials;
 
+const {
+  constructSharedArrayBuffer,
+} = require('internal/util');
+
 const {
   Buffer,
 } = require('buffer');
@@ -49,7 +50,7 @@ const {
 const BUSY_WRITE_TIMEOUT = 100;
 const kEmptyBuffer = Buffer.allocUnsafe(0);
 
-const kNil = new Int32Array(new SharedArrayBuffer(4));
+const kNil = new Int32Array(constructSharedArrayBuffer(4));
 
 function sleep(ms) {
   // Also filters out NaN, non-number types, including empty strings, but allows bigints
diff --git a/lib/internal/worker.js b/lib/internal/worker.js
@@ -23,7 +23,6 @@ const {
   SymbolFor,
   TypedArrayPrototypeFill,
   Uint32Array,
-  globalThis: { SharedArrayBuffer },
 } = primordials;
 
 const EventEmitter = require('events');
@@ -61,7 +60,10 @@ const {
 const { createMainThreadPort, destroyMainThreadPort } = require('internal/worker/messaging');
 const { deserializeError } = require('internal/error_serdes');
 const { fileURLToPath, isURL, pathToFileURL } = require('internal/url');
-const { kEmptyObject } = require('internal/util');
+const {
+  constructSharedArrayBuffer,
+  kEmptyObject,
+} = require('internal/util');
 const { validateArray, validateString, validateObject, validateNumber } = require('internal/validators');
 const {
   throwIfBuildingSnapshot,
@@ -105,9 +107,8 @@ let cwdCounter;
 
 const environmentData = new SafeMap();
 
-// SharedArrayBuffers can be disabled with --enable-sharedarraybuffer-per-context.
-if (isMainThread && SharedArrayBuffer !== undefined) {
-  cwdCounter = new Uint32Array(new SharedArrayBuffer(4));
+if (isMainThread) {
+  cwdCounter = new Uint32Array(constructSharedArrayBuffer(4));
   const originalChdir = process.chdir;
   process.chdir = function(path) {
     AtomicsAdd(cwdCounter, 0, 1);
diff --git a/lib/internal/worker/messaging.js b/lib/internal/worker/messaging.js
@@ -6,18 +6,17 @@ const {
   AtomicsWaitAsync,
   Int32Array,
   SafeMap,
-  globalThis,
 } = primordials;
 
-const {
-  SharedArrayBuffer,
-} = globalThis;
-
 const {
   isMainThread,
   threadId: currentThreadId,
 } = internalBinding('worker');
 
+const {
+  constructSharedArrayBuffer,
+} = require('internal/util');
+
 const {
   codes: {
     ERR_WORKER_MESSAGING_ERRORED,
@@ -203,7 +202,7 @@ async function postMessageToThread(threadId, value, transferList, timeout) {
     throw new ERR_WORKER_MESSAGING_SAME_THREAD();
   }
 
-  const memory = new SharedArrayBuffer(WORKER_MESSAGING_SHARED_DATA);
+  const memory = constructSharedArrayBuffer(WORKER_MESSAGING_SHARED_DATA);
   const status = new Int32Array(memory);
   const promise = AtomicsWaitAsync(status, WORKER_MESSAGING_STATUS_INDEX, 0, timeout).value;
 
