deps: V8: cherry-pick ca5b0ec

Original commit message:

    [heap] Ensure SyntheticModule is initialized before next allocation

    Ensure that all fields of `SyntheticModule` are set before creating
    the exports hash table for it, because the latter may trigger
    garbage collection, leading to crashes.

    This has been causing failures in the Node.js CI over the last weeks,
    after making the creating of synthetic modules part of Node’s
    startup sequence.

    (I am generally not very familiar with this part of the V8
    code and there might be a better way, or possibly a way to add a
    reliable regression test, that I am not aware of.)

    Refs: nodejs#30498
    Refs: nodejs#30648
    Change-Id: I32da4b7bd888c6ec1421f34f5bd52e7bad154c1e
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1939752
    Commit-Queue: Ulan Degenbaev <[email protected]>
    Reviewed-by: Ulan Degenbaev <[email protected]>
    Cr-Commit-Position: refs/heads/master@{#65247}

Refs: v8/v8@ca5b0ec
Fixes: nodejs#30498
Fixes: nodejs#30648

Author: addaleax

common.gypi

@@ -39,7 +39,7 @@
 
     # 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.20',
+    'v8_embedder_string': '-node.21',
 
     ##### V8 defaults for Node.js #####
 

deps/v8/src/heap/factory.cc

@@ -3070,20 +3070,22 @@ Handle<SyntheticModule> Factory::NewSyntheticModule(
     Handle<String> module_name, Handle<FixedArray> export_names,
     v8::Module::SyntheticModuleEvaluationSteps evaluation_steps) {
   ReadOnlyRoots roots(isolate());
-  Handle<SyntheticModule> module(
-      SyntheticModule::cast(New(synthetic_module_map(), AllocationType::kOld)),
-      isolate());
+
   Handle<ObjectHashTable> exports =
       ObjectHashTable::New(isolate(), static_cast<int>(export_names->length()));
   Handle<Foreign> evaluation_steps_foreign =
       NewForeign(reinterpret_cast<i::Address>(evaluation_steps));
-  module->set_exports(*exports);
+
+  Handle<SyntheticModule> module(
+      SyntheticModule::cast(New(synthetic_module_map(), AllocationType::kOld)),
+      isolate());
   module->set_hash(isolate()->GenerateIdentityHash(Smi::kMaxValue));
   module->set_module_namespace(roots.undefined_value());
   module->set_status(Module::kUninstantiated);
   module->set_exception(roots.the_hole_value());
   module->set_name(*module_name);
   module->set_export_names(*export_names);
+  module->set_exports(*exports);
   module->set_evaluation_steps(*evaluation_steps_foreign);
   return module;
 }

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

@@ -23918,6 +23918,31 @@ TEST(CreateSyntheticModule) {
   CHECK_EQ(i_module->status(), i::Module::kInstantiated);
 }
 
+TEST(CreateSyntheticModuleGC) {
+  // Try to make sure that CreateSyntheticModule() deals well with a GC
+  // happening during its execution.
+  i::FLAG_gc_interval = 10;
+  i::FLAG_inline_new = false;
+
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::Isolate::Scope iscope(isolate);
+  v8::HandleScope scope(isolate);
+  v8::Local<v8::Context> context = v8::Context::New(isolate);
+  v8::Context::Scope cscope(context);
+
+  std::vector<v8::Local<v8::String>> export_names{v8_str("default")};
+  v8::Local<v8::String> module_name =
+      v8_str("CreateSyntheticModule-TestSyntheticModuleGC");
+
+  for (int i = 0; i < 200; i++) {
+    Local<Module> module = v8::Module::CreateSyntheticModule(
+        isolate, module_name, export_names,
+        UnexpectedSyntheticModuleEvaluationStepsCallback);
+    USE(module);
+  }
+}
+
 TEST(SyntheticModuleSetExports) {
   LocalContext env;
   v8::Isolate* isolate = env->GetIsolate();