[modules] Implement SyntheticModule::ResolveExport and SyntheticModule::Evaluate.

ResolveExport and Evaluate are the final unimplemented SyntheticModule methods; with this
change the implementation is complete.

Test-api unit tests are also provided.

Bug: v8:9292
Change-Id: Ieb7643cc5b6495dd201a51f04199d2406a703e52
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1681187
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Dan Clark <daniec@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#62582}

include/v8.h

@@ -1330,9 +1330,12 @@ class V8_EXPORT Module {
   /*
    * Callback defined in the embedder.  This is responsible for setting
    * the module's exported values with calls to SetSyntheticModuleExport().
+   * The callback must return a Value to indicate success (where no
+   * exception was thrown) and return an empy MaybeLocal to indicate falure
+   * (where an exception was thrown).
    */
-  typedef bool (*SyntheticModuleEvaluationSteps)(Local<Context> context,
-                                                 Local<Module> module);
+  typedef MaybeLocal<Value> (*SyntheticModuleEvaluationSteps)(
+      Local<Context> context, Local<Module> module);
 
   /**
    * Creates a new SyntheticModule with the specified export names, where

src/objects/module.cc

@@ -138,6 +138,9 @@ MaybeHandle<Cell> Module::ResolveExport(Isolate* isolate, Handle<Module> module,
                                         Handle<String> export_name,
                                         MessageLocation loc, bool must_resolve,
                                         Module::ResolveSet* resolve_set) {
+  DCHECK_GE(module->status(), kPreInstantiating);
+  DCHECK_NE(module->status(), kEvaluating);
+
   if (module->IsSourceTextModule()) {
     return SourceTextModule::ResolveExport(
         isolate, Handle<SourceTextModule>::cast(module), module_specifier,
@@ -145,7 +148,7 @@ MaybeHandle<Cell> Module::ResolveExport(Isolate* isolate, Handle<Module> module,
   } else {
     return SyntheticModule::ResolveExport(
         isolate, Handle<SyntheticModule>::cast(module), module_specifier,
-        export_name, loc, must_resolve, resolve_set);
+        export_name, loc, must_resolve);
   }
 }
 

src/objects/source-text-module.cc

@@ -173,8 +173,6 @@ MaybeHandle<Cell> SourceTextModule::ResolveExport(
     Isolate* isolate, Handle<SourceTextModule> module,
     Handle<String> module_specifier, Handle<String> export_name,
     MessageLocation loc, bool must_resolve, Module::ResolveSet* resolve_set) {
-  DCHECK_GE(module->status(), kPreInstantiating);
-  DCHECK_NE(module->status(), kEvaluating);
   Handle<Object> object(module->exports().Lookup(export_name), isolate);
   if (object->IsCell()) {
     // Already resolved (e.g. because it's a local export).

src/objects/synthetic-module.cc

@@ -34,8 +34,20 @@ void SyntheticModule::SetExport(Isolate* isolate,
 MaybeHandle<Cell> SyntheticModule::ResolveExport(
     Isolate* isolate, Handle<SyntheticModule> module,
     Handle<String> module_specifier, Handle<String> export_name,
-    MessageLocation loc, bool must_resolve, ResolveSet* resolve_set) {
-  UNREACHABLE();  // TODO(SyntheticModules) implement
+    MessageLocation loc, bool must_resolve) {
+  Handle<Object> object(module->exports().Lookup(export_name), isolate);
+  if (object->IsCell()) {
+    return Handle<Cell>::cast(object);
+  }
+
+  if (must_resolve) {
+    return isolate->Throw<Cell>(
+        isolate->factory()->NewSyntaxError(MessageTemplate::kUnresolvableExport,
+                                           module_specifier, export_name),
+        &loc);
+  }
+
+  return MaybeHandle<Cell>();
 }
 
 // Implements Synthetic Module Record's Instantiate concrete method :
@@ -73,7 +85,23 @@ bool SyntheticModule::FinishInstantiate(Isolate* isolate,
 // https://heycam.github.io/webidl/#smr-evaluate
 MaybeHandle<Object> SyntheticModule::Evaluate(Isolate* isolate,
                                               Handle<SyntheticModule> module) {
-  UNREACHABLE();  // TODO(SyntheticModules) implement
+  module->SetStatus(kEvaluating);
+
+  v8::Module::SyntheticModuleEvaluationSteps evaluation_steps =
+      FUNCTION_CAST<v8::Module::SyntheticModuleEvaluationSteps>(
+          module->evaluation_steps().foreign_address());
+  v8::Local<v8::Value> result;
+  if (!evaluation_steps(
+           Utils::ToLocal(Handle<Context>::cast(isolate->native_context())),
+           Utils::ToLocal(Handle<Module>::cast(module)))
+           .ToLocal(&result)) {
+    isolate->PromoteScheduledException();
+    module->RecordError(isolate);
+    return MaybeHandle<Object>();
+  }
+
+  module->SetStatus(kEvaluated);
+  return Utils::OpenHandle(*result);
 }
 
 }  // namespace internal

src/objects/synthetic-module.h

@@ -47,7 +47,7 @@ class SyntheticModule : public Module {
   static V8_WARN_UNUSED_RESULT MaybeHandle<Cell> ResolveExport(
       Isolate* isolate, Handle<SyntheticModule> module,
       Handle<String> module_specifier, Handle<String> export_name,
-      MessageLocation loc, bool must_resolve, ResolveSet* resolve_set);
+      MessageLocation loc, bool must_resolve);
 
   static V8_WARN_UNUSED_RESULT bool PrepareInstantiate(
       Isolate* isolate, Handle<SyntheticModule> module,

test/cctest/test-api.cc

@@ -23566,11 +23566,33 @@ v8::MaybeLocal<Module> UnexpectedModuleResolveCallback(Local<Context> context,
   CHECK_WITH_MSG(false, "Unexpected call to resolve callback");
 }
 
-bool UnexpectedSyntheticModuleEvaluationStepsCallback(Local<Context> context,
-                                                      Local<Module> module) {
+v8::MaybeLocal<Value> UnexpectedSyntheticModuleEvaluationStepsCallback(
+    Local<Context> context, Local<Module> module) {
   CHECK_WITH_MSG(false, "Unexpected call to synthetic module re callback");
 }
 
+static int synthetic_module_callback_count;
+
+v8::MaybeLocal<Value> SyntheticModuleEvaluationStepsCallback(
+    Local<Context> context, Local<Module> module) {
+  synthetic_module_callback_count++;
+  return v8::Undefined(reinterpret_cast<v8::Isolate*>(context->GetIsolate()));
+}
+
+v8::MaybeLocal<Value> SyntheticModuleEvaluationStepsCallbackFail(
+    Local<Context> context, Local<Module> module) {
+  synthetic_module_callback_count++;
+  context->GetIsolate()->ThrowException(
+      v8_str("SyntheticModuleEvaluationStepsCallbackFail exception"));
+  return v8::MaybeLocal<Value>();
+}
+
+v8::MaybeLocal<Value> SyntheticModuleEvaluationStepsCallbackSetExport(
+    Local<Context> context, Local<Module> module) {
+  module->SetSyntheticModuleExport(v8_str("test_export"), v8_num(42));
+  return v8::Undefined(reinterpret_cast<v8::Isolate*>(context->GetIsolate()));
+}
+
 namespace {
 
 Local<Module> CompileAndInstantiateModule(v8::Isolate* isolate,
@@ -23628,6 +23650,28 @@ Local<Module> CompileAndInstantiateModuleFromCache(
 
 }  // namespace
 
+v8::MaybeLocal<Module> SyntheticModuleResolveCallback(Local<Context> context,
+                                                      Local<String> specifier,
+                                                      Local<Module> referrer) {
+  std::vector<v8::Local<v8::String>> export_names{v8_str("test_export")};
+  Local<Module> module = CreateAndInstantiateSyntheticModule(
+      context->GetIsolate(),
+      v8_str("SyntheticModuleResolveCallback-TestSyntheticModule"), context,
+      export_names, SyntheticModuleEvaluationStepsCallbackSetExport);
+  return v8::MaybeLocal<Module>(module);
+}
+
+v8::MaybeLocal<Module> SyntheticModuleThatThrowsDuringEvaluateResolveCallback(
+    Local<Context> context, Local<String> specifier, Local<Module> referrer) {
+  std::vector<v8::Local<v8::String>> export_names{v8_str("test_export")};
+  Local<Module> module = CreateAndInstantiateSyntheticModule(
+      context->GetIsolate(),
+      v8_str("SyntheticModuleThatThrowsDuringEvaluateResolveCallback-"
+             "TestSyntheticModule"),
+      context, export_names, SyntheticModuleEvaluationStepsCallbackFail);
+  return v8::MaybeLocal<Module>(module);
+}
+
 TEST(ModuleCodeCache) {
   v8::Isolate::CreateParams create_params;
   create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
@@ -23763,6 +23807,144 @@ TEST(SyntheticModuleSetExports) {
             ->Equals(*v8::Utils::OpenHandle(*bar_string)));
 }
 
+TEST(SyntheticModuleEvaluationStepsNoThrow) {
+  synthetic_module_callback_count = 0;
+  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")};
+
+  Local<Module> module = CreateAndInstantiateSyntheticModule(
+      isolate,
+      v8_str("SyntheticModuleEvaluationStepsNoThrow-TestSyntheticModule"),
+      context, export_names, SyntheticModuleEvaluationStepsCallback);
+  CHECK_EQ(synthetic_module_callback_count, 0);
+  Local<Value> completion_value = module->Evaluate(context).ToLocalChecked();
+  CHECK(completion_value->IsUndefined());
+  CHECK_EQ(synthetic_module_callback_count, 1);
+  CHECK_EQ(module->GetStatus(), Module::kEvaluated);
+}
+
+TEST(SyntheticModuleEvaluationStepsThrow) {
+  synthetic_module_callback_count = 0;
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::Isolate::Scope iscope(isolate);
+  v8::HandleScope scope(isolate);
+  v8::Local<v8::Context> context = CcTest::isolate()->GetCurrentContext();
+  v8::Context::Scope cscope(context);
+
+  std::vector<v8::Local<v8::String>> export_names{v8_str("default")};
+
+  Local<Module> module = CreateAndInstantiateSyntheticModule(
+      isolate,
+      v8_str("SyntheticModuleEvaluationStepsThrow-TestSyntheticModule"),
+      context, export_names, SyntheticModuleEvaluationStepsCallbackFail);
+  TryCatch try_catch(isolate);
+  CHECK_EQ(synthetic_module_callback_count, 0);
+  v8::MaybeLocal<Value> completion_value = module->Evaluate(context);
+  CHECK(completion_value.IsEmpty());
+  CHECK_EQ(synthetic_module_callback_count, 1);
+  CHECK_EQ(module->GetStatus(), Module::kErrored);
+  CHECK(try_catch.HasCaught());
+}
+
+TEST(SyntheticModuleEvaluationStepsSetExport) {
+  synthetic_module_callback_count = 0;
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  auto i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  v8::Isolate::Scope iscope(isolate);
+  v8::HandleScope scope(isolate);
+  v8::Local<v8::Context> context = v8::Context::New(isolate);
+  v8::Context::Scope cscope(context);
+
+  Local<String> test_export_string = v8_str("test_export");
+  std::vector<v8::Local<v8::String>> export_names{test_export_string};
+
+  Local<Module> module = CreateAndInstantiateSyntheticModule(
+      isolate,
+      v8_str("SyntheticModuleEvaluationStepsSetExport-TestSyntheticModule"),
+      context, export_names, SyntheticModuleEvaluationStepsCallbackSetExport);
+
+  i::Handle<i::SyntheticModule> i_module =
+      i::Handle<i::SyntheticModule>::cast(v8::Utils::OpenHandle(*module));
+  i::Handle<i::ObjectHashTable> exports(i_module->exports(), i_isolate);
+
+  i::Handle<i::Cell> test_export_cell =
+      i::Handle<i::Cell>::cast(i::Handle<i::Object>(
+          exports->Lookup(v8::Utils::OpenHandle(*test_export_string)),
+          i_isolate));
+  CHECK(test_export_cell->value().IsUndefined());
+
+  Local<Value> completion_value = module->Evaluate(context).ToLocalChecked();
+  CHECK(completion_value->IsUndefined());
+  CHECK_EQ(42, test_export_cell->value().Number());
+  CHECK_EQ(module->GetStatus(), Module::kEvaluated);
+}
+
+TEST(ImportFromSyntheticModule) {
+  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);
+
+  Local<String> url = v8_str("www.test.com");
+  Local<String> source_text = v8_str(
+      "import {test_export} from './synthetic.module';"
+      "(function() { return test_export; })();");
+  v8::ScriptOrigin origin(url, Local<v8::Integer>(), Local<v8::Integer>(),
+                          Local<v8::Boolean>(), Local<v8::Integer>(),
+                          Local<v8::Value>(), Local<v8::Boolean>(),
+                          Local<v8::Boolean>(), True(isolate));
+  v8::ScriptCompiler::Source source(source_text, origin);
+  Local<Module> module =
+      v8::ScriptCompiler::CompileModule(isolate, &source).ToLocalChecked();
+  module->InstantiateModule(context, SyntheticModuleResolveCallback)
+      .ToChecked();
+
+  Local<Value> completion_value = module->Evaluate(context).ToLocalChecked();
+  CHECK_EQ(42, completion_value->Int32Value(context).FromJust());
+}
+
+TEST(ImportFromSyntheticModuleThrow) {
+  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);
+
+  Local<String> url = v8_str("www.test.com");
+  Local<String> source_text = v8_str(
+      "import {test_export} from './synthetic.module';"
+      "(function() { return test_export; })();");
+  v8::ScriptOrigin origin(url, Local<v8::Integer>(), Local<v8::Integer>(),
+                          Local<v8::Boolean>(), Local<v8::Integer>(),
+                          Local<v8::Value>(), Local<v8::Boolean>(),
+                          Local<v8::Boolean>(), True(isolate));
+  v8::ScriptCompiler::Source source(source_text, origin);
+  Local<Module> module =
+      v8::ScriptCompiler::CompileModule(isolate, &source).ToLocalChecked();
+  module
+      ->InstantiateModule(
+          context, SyntheticModuleThatThrowsDuringEvaluateResolveCallback)
+      .ToChecked();
+
+  CHECK_EQ(module->GetStatus(), Module::kInstantiated);
+  TryCatch try_catch(isolate);
+  v8::MaybeLocal<Value> completion_value = module->Evaluate(context);
+  CHECK(completion_value.IsEmpty());
+  CHECK_EQ(module->GetStatus(), Module::kErrored);
+  CHECK(try_catch.HasCaught());
+}
+
 // Tests that the code cache does not confuse the same source code compiled as a
 // script and as a module.
 TEST(CodeCacheModuleScriptMismatch) {