[v18.x] backport startup performance patches

common.gypi

@@ -36,7 +36,7 @@
 
     # Reset this number to 0 on major V8 upgrades.
     # Increment by one for each non-official patch applied to deps/v8.
-    'v8_embedder_string': '-node.26',
+    'v8_embedder_string': '-node.27',
 
     ##### V8 defaults for Node.js #####
 

deps/v8/src/snapshot/deserializer.cc

@@ -427,6 +427,8 @@ void Deserializer<IsolateT>::PostProcessNewJSReceiver(
         reinterpret_cast<uint8_t*>(backing_store) + data_view.byte_offset());
   } else if (InstanceTypeChecker::IsJSTypedArray(instance_type)) {
     auto typed_array = JSTypedArray::cast(raw_obj);
+    // Note: ByteArray objects must not be deferred s.t. they are
+    // available here for is_on_heap(). See also: CanBeDeferred.
     // Fixup typed array pointers.
     if (typed_array.is_on_heap()) {
       typed_array.AddExternalPointerCompensationForDeserialization(
@@ -517,7 +519,10 @@ void Deserializer<IsolateT>::PostProcessNewObject(Handle<Map> map,
         // to |ObjectDeserializer::CommitPostProcessedObjects()|.
         new_allocation_sites_.push_back(Handle<AllocationSite>::cast(obj));
       } else {
-        DCHECK(CanBeDeferred(*obj));
+        // We dont defer ByteArray because JSTypedArray needs the base_pointer
+        // ByteArray immediately if it's on heap.
+        DCHECK(CanBeDeferred(*obj) ||
+               InstanceTypeChecker::IsByteArray(instance_type));
       }
     }
   }

deps/v8/src/snapshot/serializer-deserializer.cc

@@ -51,10 +51,13 @@ bool SerializerDeserializer::CanBeDeferred(HeapObject o) {
   // 3. JS objects with embedder fields cannot be deferred because the
   // serialize/deserialize callbacks need the back reference immediately to
   // identify the object.
+  // 4. ByteArray cannot be deferred as JSTypedArray needs the base_pointer
+  // ByteArray immediately if it's on heap.
   // TODO(leszeks): Could we defer string serialization if forward references
   // were resolved after object post processing?
   return !o.IsMap() && !o.IsInternalizedString() &&
-         !(o.IsJSObject() && JSObject::cast(o).GetEmbedderFieldCount() > 0);
+         !(o.IsJSObject() && JSObject::cast(o).GetEmbedderFieldCount() > 0) &&
+         !o.IsByteArray();
 }
 
 void SerializerDeserializer::RestoreExternalReferenceRedirector(

deps/v8/test/cctest/test-serialize.cc

@@ -4990,6 +4990,46 @@ UNINITIALIZED_TEST(SnapshotCreatorAnonClassWithKeep) {
   delete[] blob.data;
 }
 
+UNINITIALIZED_TEST(SnapshotCreatorDontDeferByteArrayForTypedArray) {
+  DisableAlwaysOpt();
+  v8::StartupData blob;
+  {
+    v8::SnapshotCreator creator;
+    v8::Isolate* isolate = creator.GetIsolate();
+    {
+      v8::HandleScope handle_scope(isolate);
+
+      v8::Local<v8::Context> context = v8::Context::New(isolate);
+      v8::Context::Scope context_scope(context);
+      CompileRun(
+          "const z = new Uint8Array(1);\n"
+          "class A { \n"
+          "  static x() { \n"
+          "  } \n"
+          "} \n"
+          "class B extends A {} \n"
+          "B.foo = ''; \n"
+          "class C extends B {} \n"
+          "class D extends C {} \n"
+          "class E extends B {} \n"
+          "function F() {} \n"
+          "Object.setPrototypeOf(F, D); \n");
+      creator.SetDefaultContext(context);
+    }
+
+    blob =
+        creator.CreateBlob(v8::SnapshotCreator::FunctionCodeHandling::kClear);
+    CHECK(blob.raw_size > 0 && blob.data != nullptr);
+  }
+  {
+    SnapshotCreator creator(nullptr, &blob);
+    v8::Isolate* isolate = creator.GetIsolate();
+    v8::HandleScope scope(isolate);
+    USE(v8::Context::New(isolate));
+  }
+  delete[] blob.data;
+}
+
 class V8_NODISCARD DisableLazySourcePositionScope {
  public:
   DisableLazySourcePositionScope()

lib/buffer.js

@@ -85,6 +85,7 @@ const {
   lazyDOMException,
   normalizeEncoding,
   kIsEncodingSymbol,
+  defineLazyProperties,
 } = require('internal/util');
 const {
   isAnyArrayBuffer,
@@ -128,15 +129,6 @@ const {
   createUnsafeBuffer,
 } = require('internal/buffer');
 
-const {
-  Blob,
-  resolveObjectURL,
-} = require('internal/blob');
-
-const {
-  File,
-} = require('internal/file');
-
 FastBuffer.prototype.constructor = Buffer;
 Buffer.prototype = FastBuffer.prototype;
 addBufferPrototypeMethods(Buffer.prototype);
@@ -1382,9 +1374,6 @@ function isAscii(input) {
 }
 
 module.exports = {
-  Blob,
-  File,
-  resolveObjectURL,
   Buffer,
   SlowBuffer,
   transcode,
@@ -1413,3 +1402,14 @@ ObjectDefineProperties(module.exports, {
     set(val) { INSPECT_MAX_BYTES = val; },
   },
 });
+
+defineLazyProperties(
+  module.exports,
+  'internal/blob',
+  ['Blob', 'resolveObjectURL'],
+);
+defineLazyProperties(
+  module.exports,
+  'internal/file',
+  ['File'],
+);

lib/fs.js

@@ -87,6 +87,7 @@ const {
     custom: kCustomPromisifiedSymbol,
   },
   SideEffectFreeRegExpPrototypeExec,
+  defineLazyProperties,
 } = require('internal/util');
 const {
   constants: {
@@ -125,11 +126,6 @@ const {
   validatePrimitiveStringAfterArrayBufferView,
   warnOnNonPortableTemplate,
 } = require('internal/fs/utils');
-const {
-  Dir,
-  opendir,
-  opendirSync,
-} = require('internal/fs/dir');
 const {
   CHAR_FORWARD_SLASH,
   CHAR_BACKWARD_SLASH,
@@ -146,9 +142,6 @@ const {
   validateString,
 } = require('internal/validators');
 
-const watchers = require('internal/fs/watchers');
-const ReadFileContext = require('internal/fs/read_file_context');
-
 let truncateWarn = true;
 let fs;
 
@@ -392,6 +385,7 @@ function checkAborted(signal, callback) {
 function readFile(path, options, callback) {
   callback = maybeCallback(callback || options);
   options = getOptions(options, { flag: 'r' });
+  const ReadFileContext = require('internal/fs/read_file_context');
   const context = new ReadFileContext(callback, options.encoding);
   context.isUserFd = isFd(path); // File descriptor ownership
 
@@ -2422,12 +2416,13 @@ function watch(filename, options, listener) {
   if (options.recursive === undefined) options.recursive = false;
   if (options.recursive && !(isOSX || isWindows))
     throw new ERR_FEATURE_UNAVAILABLE_ON_PLATFORM('watch recursively');
+
+  const watchers = require('internal/fs/watchers');
   const watcher = new watchers.FSWatcher();
   watcher[watchers.kFSWatchStart](filename,
                                   options.persistent,
                                   options.recursive,
                                   options.encoding);
-
   if (listener) {
     watcher.addListener('change', listener);
   }
@@ -2486,7 +2481,7 @@ function watchFile(filename, options, listener) {
   validateFunction(listener, 'listener');
 
   stat = statWatchers.get(filename);
-
+  const watchers = require('internal/fs/watchers');
   if (stat === undefined) {
     stat = new watchers.StatWatcher(options.bigint);
     stat[watchers.kFSStatWatcherStart](filename,
@@ -2512,7 +2507,7 @@ function unwatchFile(filename, listener) {
   const stat = statWatchers.get(filename);
 
   if (stat === undefined) return;
-
+  const watchers = require('internal/fs/watchers');
   if (typeof listener === 'function') {
     const beforeListenerCount = stat.listenerCount('change');
     stat.removeListener('change', listener);
@@ -3116,8 +3111,6 @@ module.exports = fs = {
   mkdtempSync,
   open,
   openSync,
-  opendir,
-  opendirSync,
   readdir,
   readdirSync,
   read,
@@ -3157,7 +3150,6 @@ module.exports = fs = {
   writeSync,
   writev,
   writevSync,
-  Dir,
   Dirent,
   Stats,
 
@@ -3203,6 +3195,12 @@ module.exports = fs = {
   _toUnixTimestamp: toUnixTimestamp,
 };
 
+defineLazyProperties(
+  fs,
+  'internal/fs/dir',
+  ['Dir', 'opendir', 'opendirSync'],
+);
+
 ObjectDefineProperties(fs, {
   F_OK: { __proto__: null, enumerable: true, value: F_OK || 0 },
   R_OK: { __proto__: null, enumerable: true, value: R_OK || 0 },

lib/internal/async_hooks.js

@@ -8,8 +8,6 @@ const {
   Symbol,
 } = primordials;
 
-const promiseHooks = require('internal/promise_hooks');
-
 const async_wrap = internalBinding('async_wrap');
 const { setCallbackTrampoline } = async_wrap;
 /* async_hook_fields is a Uint32Array wrapping the uint32_t array of
@@ -382,6 +380,7 @@ function updatePromiseHookMode() {
     initHook = destroyTracking;
   }
   if (stopPromiseHook) stopPromiseHook();
+  const promiseHooks = require('internal/promise_hooks');
   stopPromiseHook = promiseHooks.createHook({
     init: initHook,
     before: promiseBeforeHook,