bootstrap: store internal loaders in C++ via a binding

lib/internal/bootstrap/loaders.js

@@ -182,6 +182,7 @@ const loaderId = 'internal/bootstrap/loaders';
 const {
   builtinIds,
   compileFunction,
+  setInternalLoaders,
 } = internalBinding('builtins');
 
 const getOwn = (target, property, receiver) => {
@@ -373,5 +374,5 @@ function requireWithFallbackInDeps(request) {
   return requireBuiltin(request);
 }
 
-// Pass the exports back to C++ land for C++ internals to use.
-return loaderExports;
+// Store the internal loaders in C++.
+setInternalLoaders(internalBinding, requireBuiltin);

src/node_builtins.cc

@@ -647,6 +647,16 @@ void BuiltinLoader::HasCachedBuiltins(const FunctionCallbackInfo<Value>& args) {
       args.GetIsolate(), instance->code_cache_->has_code_cache));
 }
 
+void SetInternalLoaders(const FunctionCallbackInfo<Value>& args) {
+  Realm* realm = Realm::GetCurrent(args);
+  CHECK(args[0]->IsFunction());
+  CHECK(args[1]->IsFunction());
+  DCHECK(realm->internal_binding_loader().IsEmpty());
+  DCHECK(realm->builtin_module_require().IsEmpty());
+  realm->set_internal_binding_loader(args[0].As<Function>());
+  realm->set_builtin_module_require(args[1].As<Function>());
+}
+
 void BuiltinLoader::CopySourceAndCodeCacheReferenceFrom(
     const BuiltinLoader* other) {
   code_cache_ = other->code_cache_;
@@ -685,6 +695,7 @@ void BuiltinLoader::CreatePerIsolateProperties(IsolateData* isolate_data,
   SetMethod(isolate, proto, "getCacheUsage", BuiltinLoader::GetCacheUsage);
   SetMethod(isolate, proto, "compileFunction", BuiltinLoader::CompileFunction);
   SetMethod(isolate, proto, "hasCachedBuiltins", HasCachedBuiltins);
+  SetMethod(isolate, proto, "setInternalLoaders", SetInternalLoaders);
 }
 
 void BuiltinLoader::CreatePerContextProperties(Local<Object> target,
@@ -703,6 +714,7 @@ void BuiltinLoader::RegisterExternalReferences(
   registry->Register(GetCacheUsage);
   registry->Register(CompileFunction);
   registry->Register(HasCachedBuiltins);
+  registry->Register(SetInternalLoaders);
 }
 
 }  // namespace builtins

src/node_realm.cc

@@ -174,42 +174,14 @@ MaybeLocal<Value> Realm::ExecuteBootstrapper(const char* id) {
   return scope.EscapeMaybe(result);
 }
 
-MaybeLocal<Value> Realm::BootstrapInternalLoaders() {
-  EscapableHandleScope scope(isolate_);
-
-  // Bootstrap internal loaders
-  Local<Value> loader_exports;
-  if (!ExecuteBootstrapper("internal/bootstrap/loaders")
-           .ToLocal(&loader_exports)) {
-    return MaybeLocal<Value>();
-  }
-  CHECK(loader_exports->IsObject());
-  Local<Object> loader_exports_obj = loader_exports.As<Object>();
-  Local<Value> internal_binding_loader =
-      loader_exports_obj->Get(context(), env_->internal_binding_string())
-          .ToLocalChecked();
-  CHECK(internal_binding_loader->IsFunction());
-  set_internal_binding_loader(internal_binding_loader.As<Function>());
-  Local<Value> require =
-      loader_exports_obj->Get(context(), env_->require_string())
-          .ToLocalChecked();
-  CHECK(require->IsFunction());
-  set_builtin_module_require(require.As<Function>());
-
-  return scope.Escape(loader_exports);
-}
-
 MaybeLocal<Value> Realm::RunBootstrapping() {
   EscapableHandleScope scope(isolate_);
 
   CHECK(!has_run_bootstrapping_code());
 
-  if (BootstrapInternalLoaders().IsEmpty()) {
-    return MaybeLocal<Value>();
-  }
-
   Local<Value> result;
-  if (!BootstrapRealm().ToLocal(&result)) {
+  if (!ExecuteBootstrapper("internal/bootstrap/loaders").ToLocal(&result) ||
+      !BootstrapRealm().ToLocal(&result)) {
     return MaybeLocal<Value>();
   }
 

src/node_realm.h

@@ -129,7 +129,6 @@ class Realm : public MemoryRetainer {
  protected:
   ~Realm();
 
-  v8::MaybeLocal<v8::Value> BootstrapInternalLoaders();
   virtual v8::MaybeLocal<v8::Value> BootstrapRealm() = 0;
 
   Environment* env_;