// Copyright 2019 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "src/objects/source-text-module.h" #include "src/api/api-inl.h" #include "src/ast/modules.h" #include "src/builtins/accessors.h" #include "src/objects/js-generator-inl.h" #include "src/objects/module-inl.h" #include "src/objects/objects-inl.h" #include "src/objects/shared-function-info.h" #include "src/utils/ostreams.h" namespace v8 { namespace internal { struct StringHandleHash { V8_INLINE size_t operator()(Handle<String> string) const { return string->Hash(); } }; struct StringHandleEqual { V8_INLINE bool operator()(Handle<String> lhs, Handle<String> rhs) const { return lhs->Equals(*rhs); } }; class UnorderedStringSet : public std::unordered_set<Handle<String>, StringHandleHash, StringHandleEqual, ZoneAllocator<Handle<String>>> { public: explicit UnorderedStringSet(Zone* zone) : std::unordered_set<Handle<String>, StringHandleHash, StringHandleEqual, ZoneAllocator<Handle<String>>>( 2 /* bucket count */, StringHandleHash(), StringHandleEqual(), ZoneAllocator<Handle<String>>(zone)) {} }; class UnorderedStringMap : public std::unordered_map< Handle<String>, Handle<Object>, StringHandleHash, StringHandleEqual, ZoneAllocator<std::pair<const Handle<String>, Handle<Object>>>> { public: explicit UnorderedStringMap(Zone* zone) : std::unordered_map< Handle<String>, Handle<Object>, StringHandleHash, StringHandleEqual, ZoneAllocator<std::pair<const Handle<String>, Handle<Object>>>>( 2 /* bucket count */, StringHandleHash(), StringHandleEqual(), ZoneAllocator<std::pair<const Handle<String>, Handle<Object>>>( zone)) {} }; class Module::ResolveSet : public std::unordered_map< Handle<Module>, UnorderedStringSet*, ModuleHandleHash, ModuleHandleEqual, ZoneAllocator<std::pair<const Handle<Module>, UnorderedStringSet*>>> { public: explicit ResolveSet(Zone* zone) : std::unordered_map<Handle<Module>, UnorderedStringSet*, ModuleHandleHash, ModuleHandleEqual, ZoneAllocator<std::pair<const Handle<Module>, UnorderedStringSet*>>>( 2 /* bucket count */, ModuleHandleHash(), ModuleHandleEqual(), ZoneAllocator<std::pair<const Handle<Module>, UnorderedStringSet*>>( zone)), zone_(zone) {} Zone* zone() const { return zone_; } private: Zone* zone_; }; SharedFunctionInfo SourceTextModule::GetSharedFunctionInfo() const { DisallowHeapAllocation no_alloc; DCHECK_NE(status(), Module::kEvaluating); DCHECK_NE(status(), Module::kEvaluated); switch (status()) { case kUninstantiated: case kPreInstantiating: DCHECK(code().IsSharedFunctionInfo()); return SharedFunctionInfo::cast(code()); case kInstantiating: DCHECK(code().IsJSFunction()); return JSFunction::cast(code()).shared(); case kInstantiated: DCHECK(code().IsJSGeneratorObject()); return JSGeneratorObject::cast(code()).function().shared(); case kEvaluating: case kEvaluated: case kErrored: UNREACHABLE(); } UNREACHABLE(); } int SourceTextModule::ExportIndex(int cell_index) { DCHECK_EQ(SourceTextModuleDescriptor::GetCellIndexKind(cell_index), SourceTextModuleDescriptor::kExport); return cell_index - 1; } int SourceTextModule::ImportIndex(int cell_index) { DCHECK_EQ(SourceTextModuleDescriptor::GetCellIndexKind(cell_index), SourceTextModuleDescriptor::kImport); return -cell_index - 1; } void SourceTextModule::CreateIndirectExport( Isolate* isolate, Handle<SourceTextModule> module, Handle<String> name, Handle<SourceTextModuleInfoEntry> entry) { Handle<ObjectHashTable> exports(module->exports(), isolate); DCHECK(exports->Lookup(name).IsTheHole(isolate)); exports = ObjectHashTable::Put(exports, name, entry); module->set_exports(*exports); } void SourceTextModule::CreateExport(Isolate* isolate, Handle<SourceTextModule> module, int cell_index, Handle<FixedArray> names) { DCHECK_LT(0, names->length()); Handle<Cell> cell = isolate->factory()->NewCell(isolate->factory()->undefined_value()); module->regular_exports().set(ExportIndex(cell_index), *cell); Handle<ObjectHashTable> exports(module->exports(), isolate); for (int i = 0, n = names->length(); i < n; ++i) { Handle<String> name(String::cast(names->get(i)), isolate); DCHECK(exports->Lookup(name).IsTheHole(isolate)); exports = ObjectHashTable::Put(exports, name, cell); } module->set_exports(*exports); } Cell SourceTextModule::GetCell(int cell_index) { DisallowHeapAllocation no_gc; Object cell; switch (SourceTextModuleDescriptor::GetCellIndexKind(cell_index)) { case SourceTextModuleDescriptor::kImport: cell = regular_imports().get(ImportIndex(cell_index)); break; case SourceTextModuleDescriptor::kExport: cell = regular_exports().get(ExportIndex(cell_index)); break; case SourceTextModuleDescriptor::kInvalid: UNREACHABLE(); break; } return Cell::cast(cell); } Handle<Object> SourceTextModule::LoadVariable(Isolate* isolate, Handle<SourceTextModule> module, int cell_index) { return handle(module->GetCell(cell_index).value(), isolate); } void SourceTextModule::StoreVariable(Handle<SourceTextModule> module, int cell_index, Handle<Object> value) { DisallowHeapAllocation no_gc; DCHECK_EQ(SourceTextModuleDescriptor::GetCellIndexKind(cell_index), SourceTextModuleDescriptor::kExport); module->GetCell(cell_index).set_value(*value); } 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) { Handle<Object> object(module->exports().Lookup(export_name), isolate); if (object->IsCell()) { // Already resolved (e.g. because it's a local export). return Handle<Cell>::cast(object); } // Check for cycle before recursing. { // Attempt insertion with a null string set. auto result = resolve_set->insert({module, nullptr}); UnorderedStringSet*& name_set = result.first->second; if (result.second) { // |module| wasn't in the map previously, so allocate a new name set. Zone* zone = resolve_set->zone(); name_set = new (zone->New(sizeof(UnorderedStringSet))) UnorderedStringSet(zone); } else if (name_set->count(export_name)) { // Cycle detected. if (must_resolve) { return isolate->Throw<Cell>( isolate->factory()->NewSyntaxError( MessageTemplate::kCyclicModuleDependency, export_name, module_specifier), &loc); } return MaybeHandle<Cell>(); } name_set->insert(export_name); } if (object->IsSourceTextModuleInfoEntry()) { // Not yet resolved indirect export. Handle<SourceTextModuleInfoEntry> entry = Handle<SourceTextModuleInfoEntry>::cast(object); Handle<String> import_name(String::cast(entry->import_name()), isolate); Handle<Script> script(module->script(), isolate); MessageLocation new_loc(script, entry->beg_pos(), entry->end_pos()); Handle<Cell> cell; if (!ResolveImport(isolate, module, import_name, entry->module_request(), new_loc, true, resolve_set) .ToHandle(&cell)) { DCHECK(isolate->has_pending_exception()); return MaybeHandle<Cell>(); } // The export table may have changed but the entry in question should be // unchanged. Handle<ObjectHashTable> exports(module->exports(), isolate); DCHECK(exports->Lookup(export_name).IsSourceTextModuleInfoEntry()); exports = ObjectHashTable::Put(exports, export_name, cell); module->set_exports(*exports); return cell; } DCHECK(object->IsTheHole(isolate)); return SourceTextModule::ResolveExportUsingStarExports( isolate, module, module_specifier, export_name, loc, must_resolve, resolve_set); } MaybeHandle<Cell> SourceTextModule::ResolveImport( Isolate* isolate, Handle<SourceTextModule> module, Handle<String> name, int module_request, MessageLocation loc, bool must_resolve, Module::ResolveSet* resolve_set) { Handle<Module> requested_module( Module::cast(module->requested_modules().get(module_request)), isolate); Handle<String> specifier( String::cast(module->info().module_requests().get(module_request)), isolate); MaybeHandle<Cell> result = Module::ResolveExport(isolate, requested_module, specifier, name, loc, must_resolve, resolve_set); DCHECK_IMPLIES(isolate->has_pending_exception(), result.is_null()); return result; } MaybeHandle<Cell> SourceTextModule::ResolveExportUsingStarExports( Isolate* isolate, Handle<SourceTextModule> module, Handle<String> module_specifier, Handle<String> export_name, MessageLocation loc, bool must_resolve, Module::ResolveSet* resolve_set) { if (!export_name->Equals(ReadOnlyRoots(isolate).default_string())) { // Go through all star exports looking for the given name. If multiple star // exports provide the name, make sure they all map it to the same cell. Handle<Cell> unique_cell; Handle<FixedArray> special_exports(module->info().special_exports(), isolate); for (int i = 0, n = special_exports->length(); i < n; ++i) { i::Handle<i::SourceTextModuleInfoEntry> entry( i::SourceTextModuleInfoEntry::cast(special_exports->get(i)), isolate); if (!entry->export_name().IsUndefined(isolate)) { continue; // Indirect export. } Handle<Script> script(module->script(), isolate); MessageLocation new_loc(script, entry->beg_pos(), entry->end_pos()); Handle<Cell> cell; if (ResolveImport(isolate, module, export_name, entry->module_request(), new_loc, false, resolve_set) .ToHandle(&cell)) { if (unique_cell.is_null()) unique_cell = cell; if (*unique_cell != *cell) { return isolate->Throw<Cell>(isolate->factory()->NewSyntaxError( MessageTemplate::kAmbiguousExport, module_specifier, export_name), &loc); } } else if (isolate->has_pending_exception()) { return MaybeHandle<Cell>(); } } if (!unique_cell.is_null()) { // Found a unique star export for this name. Handle<ObjectHashTable> exports(module->exports(), isolate); DCHECK(exports->Lookup(export_name).IsTheHole(isolate)); exports = ObjectHashTable::Put(exports, export_name, unique_cell); module->set_exports(*exports); return unique_cell; } } // Unresolvable. if (must_resolve) { return isolate->Throw<Cell>( isolate->factory()->NewSyntaxError(MessageTemplate::kUnresolvableExport, module_specifier, export_name), &loc); } return MaybeHandle<Cell>(); } bool SourceTextModule::PrepareInstantiate( Isolate* isolate, Handle<SourceTextModule> module, v8::Local<v8::Context> context, v8::Module::ResolveCallback callback) { // Obtain requested modules. Handle<SourceTextModuleInfo> module_info(module->info(), isolate); Handle<FixedArray> module_requests(module_info->module_requests(), isolate); Handle<FixedArray> requested_modules(module->requested_modules(), isolate); for (int i = 0, length = module_requests->length(); i < length; ++i) { Handle<String> specifier(String::cast(module_requests->get(i)), isolate); v8::Local<v8::Module> api_requested_module; if (!callback(context, v8::Utils::ToLocal(specifier), v8::Utils::ToLocal(Handle<Module>::cast(module))) .ToLocal(&api_requested_module)) { isolate->PromoteScheduledException(); return false; } Handle<Module> requested_module = Utils::OpenHandle(*api_requested_module); requested_modules->set(i, *requested_module); } // Recurse. for (int i = 0, length = requested_modules->length(); i < length; ++i) { Handle<Module> requested_module(Module::cast(requested_modules->get(i)), isolate); if (!Module::PrepareInstantiate(isolate, requested_module, context, callback)) { return false; } } // Set up local exports. // TODO(neis): Create regular_exports array here instead of in factory method? for (int i = 0, n = module_info->RegularExportCount(); i < n; ++i) { int cell_index = module_info->RegularExportCellIndex(i); Handle<FixedArray> export_names(module_info->RegularExportExportNames(i), isolate); CreateExport(isolate, module, cell_index, export_names); } // Partially set up indirect exports. // For each indirect export, we create the appropriate slot in the export // table and store its SourceTextModuleInfoEntry there. When we later find // the correct Cell in the module that actually provides the value, we replace // the SourceTextModuleInfoEntry by that Cell (see ResolveExport). Handle<FixedArray> special_exports(module_info->special_exports(), isolate); for (int i = 0, n = special_exports->length(); i < n; ++i) { Handle<SourceTextModuleInfoEntry> entry( SourceTextModuleInfoEntry::cast(special_exports->get(i)), isolate); Handle<Object> export_name(entry->export_name(), isolate); if (export_name->IsUndefined(isolate)) continue; // Star export. CreateIndirectExport(isolate, module, Handle<String>::cast(export_name), entry); } DCHECK_EQ(module->status(), kPreInstantiating); return true; } bool SourceTextModule::RunInitializationCode(Isolate* isolate, Handle<SourceTextModule> module) { DCHECK_EQ(module->status(), kInstantiating); Handle<JSFunction> function(JSFunction::cast(module->code()), isolate); DCHECK_EQ(MODULE_SCOPE, function->shared().scope_info().scope_type()); Handle<Object> receiver = isolate->factory()->undefined_value(); Handle<Object> argv[] = {module}; MaybeHandle<Object> maybe_generator = Execution::Call(isolate, function, receiver, arraysize(argv), argv); Handle<Object> generator; if (!maybe_generator.ToHandle(&generator)) { DCHECK(isolate->has_pending_exception()); return false; } DCHECK_EQ(*function, Handle<JSGeneratorObject>::cast(generator)->function()); module->set_code(*generator); return true; } bool SourceTextModule::MaybeTransitionComponent( Isolate* isolate, Handle<SourceTextModule> module, ZoneForwardList<Handle<SourceTextModule>>* stack, Status new_status) { DCHECK(new_status == kInstantiated || new_status == kEvaluated); SLOW_DCHECK( // {module} is on the {stack}. std::count_if(stack->begin(), stack->end(), [&](Handle<Module> m) { return *m == *module; }) == 1); DCHECK_LE(module->dfs_ancestor_index(), module->dfs_index()); if (module->dfs_ancestor_index() == module->dfs_index()) { // This is the root of its strongly connected component. Handle<SourceTextModule> ancestor; do { ancestor = stack->front(); stack->pop_front(); DCHECK_EQ(ancestor->status(), new_status == kInstantiated ? kInstantiating : kEvaluating); if (new_status == kInstantiated) { if (!SourceTextModule::RunInitializationCode(isolate, ancestor)) return false; } ancestor->SetStatus(new_status); } while (*ancestor != *module); } return true; } bool SourceTextModule::FinishInstantiate( Isolate* isolate, Handle<SourceTextModule> module, ZoneForwardList<Handle<SourceTextModule>>* stack, unsigned* dfs_index, Zone* zone) { // Instantiate SharedFunctionInfo and mark module as instantiating for // the recursion. Handle<SharedFunctionInfo> shared(SharedFunctionInfo::cast(module->code()), isolate); Handle<JSFunction> function = isolate->factory()->NewFunctionFromSharedFunctionInfo( shared, isolate->native_context()); module->set_code(*function); module->SetStatus(kInstantiating); module->set_dfs_index(*dfs_index); module->set_dfs_ancestor_index(*dfs_index); stack->push_front(module); (*dfs_index)++; // Recurse. Handle<FixedArray> requested_modules(module->requested_modules(), isolate); for (int i = 0, length = requested_modules->length(); i < length; ++i) { Handle<Module> requested_module(Module::cast(requested_modules->get(i)), isolate); if (!Module::FinishInstantiate(isolate, requested_module, stack, dfs_index, zone)) { return false; } DCHECK_NE(requested_module->status(), kEvaluating); DCHECK_GE(requested_module->status(), kInstantiating); SLOW_DCHECK( // {requested_module} is instantiating iff it's on the {stack}. (requested_module->status() == kInstantiating) == std::count_if(stack->begin(), stack->end(), [&](Handle<Module> m) { return *m == *requested_module; })); if (requested_module->status() == kInstantiating) { // SyntheticModules go straight to kInstantiated so this must be a // SourceTextModule module->set_dfs_ancestor_index( std::min(module->dfs_ancestor_index(), Handle<SourceTextModule>::cast(requested_module) ->dfs_ancestor_index())); } } Handle<Script> script(module->script(), isolate); Handle<SourceTextModuleInfo> module_info(module->info(), isolate); // Resolve imports. Handle<FixedArray> regular_imports(module_info->regular_imports(), isolate); for (int i = 0, n = regular_imports->length(); i < n; ++i) { Handle<SourceTextModuleInfoEntry> entry( SourceTextModuleInfoEntry::cast(regular_imports->get(i)), isolate); Handle<String> name(String::cast(entry->import_name()), isolate); MessageLocation loc(script, entry->beg_pos(), entry->end_pos()); ResolveSet resolve_set(zone); Handle<Cell> cell; if (!ResolveImport(isolate, module, name, entry->module_request(), loc, true, &resolve_set) .ToHandle(&cell)) { return false; } module->regular_imports().set(ImportIndex(entry->cell_index()), *cell); } // Resolve indirect exports. Handle<FixedArray> special_exports(module_info->special_exports(), isolate); for (int i = 0, n = special_exports->length(); i < n; ++i) { Handle<SourceTextModuleInfoEntry> entry( SourceTextModuleInfoEntry::cast(special_exports->get(i)), isolate); Handle<Object> name(entry->export_name(), isolate); if (name->IsUndefined(isolate)) continue; // Star export. MessageLocation loc(script, entry->beg_pos(), entry->end_pos()); ResolveSet resolve_set(zone); if (ResolveExport(isolate, module, Handle<String>(), Handle<String>::cast(name), loc, true, &resolve_set) .is_null()) { return false; } } return MaybeTransitionComponent(isolate, module, stack, kInstantiated); } void SourceTextModule::FetchStarExports(Isolate* isolate, Handle<SourceTextModule> module, Zone* zone, UnorderedModuleSet* visited) { DCHECK_GE(module->status(), Module::kInstantiating); if (module->module_namespace().IsJSModuleNamespace()) return; // Shortcut. bool cycle = !visited->insert(module).second; if (cycle) return; Handle<ObjectHashTable> exports(module->exports(), isolate); UnorderedStringMap more_exports(zone); // TODO(neis): Only allocate more_exports if there are star exports. // Maybe split special_exports into indirect_exports and star_exports. ReadOnlyRoots roots(isolate); Handle<FixedArray> special_exports(module->info().special_exports(), isolate); for (int i = 0, n = special_exports->length(); i < n; ++i) { Handle<SourceTextModuleInfoEntry> entry( SourceTextModuleInfoEntry::cast(special_exports->get(i)), isolate); if (!entry->export_name().IsUndefined(roots)) { continue; // Indirect export. } Handle<Module> requested_module( Module::cast(module->requested_modules().get(entry->module_request())), isolate); // Recurse. if (requested_module->IsSourceTextModule()) FetchStarExports(isolate, Handle<SourceTextModule>::cast(requested_module), zone, visited); // Collect all of [requested_module]'s exports that must be added to // [module]'s exports (i.e. to [exports]). We record these in // [more_exports]. Ambiguities (conflicting exports) are marked by mapping // the name to undefined instead of a Cell. Handle<ObjectHashTable> requested_exports(requested_module->exports(), isolate); for (int i = 0, n = requested_exports->Capacity(); i < n; ++i) { Object key; if (!requested_exports->ToKey(roots, i, &key)) continue; Handle<String> name(String::cast(key), isolate); if (name->Equals(roots.default_string())) continue; if (!exports->Lookup(name).IsTheHole(roots)) continue; Handle<Cell> cell(Cell::cast(requested_exports->ValueAt(i)), isolate); auto insert_result = more_exports.insert(std::make_pair(name, cell)); if (!insert_result.second) { auto it = insert_result.first; if (*it->second == *cell || it->second->IsUndefined(roots)) { // We already recorded this mapping before, or the name is already // known to be ambiguous. In either case, there's nothing to do. } else { DCHECK(it->second->IsCell()); // Different star exports provide different cells for this name, hence // mark the name as ambiguous. it->second = roots.undefined_value_handle(); } } } } // Copy [more_exports] into [exports]. for (const auto& elem : more_exports) { if (elem.second->IsUndefined(isolate)) continue; // Ambiguous export. DCHECK(!elem.first->Equals(ReadOnlyRoots(isolate).default_string())); DCHECK(elem.second->IsCell()); exports = ObjectHashTable::Put(exports, elem.first, elem.second); } module->set_exports(*exports); } Handle<JSModuleNamespace> SourceTextModule::GetModuleNamespace( Isolate* isolate, Handle<SourceTextModule> module, int module_request) { Handle<Module> requested_module( Module::cast(module->requested_modules().get(module_request)), isolate); return Module::GetModuleNamespace(isolate, requested_module); } MaybeHandle<Object> SourceTextModule::Evaluate( Isolate* isolate, Handle<SourceTextModule> module, ZoneForwardList<Handle<SourceTextModule>>* stack, unsigned* dfs_index) { Handle<JSGeneratorObject> generator(JSGeneratorObject::cast(module->code()), isolate); module->set_code( generator->function().shared().scope_info().ModuleDescriptorInfo()); module->SetStatus(kEvaluating); module->set_dfs_index(*dfs_index); module->set_dfs_ancestor_index(*dfs_index); stack->push_front(module); (*dfs_index)++; // Recursion. Handle<FixedArray> requested_modules(module->requested_modules(), isolate); for (int i = 0, length = requested_modules->length(); i < length; ++i) { Handle<Module> requested_module(Module::cast(requested_modules->get(i)), isolate); RETURN_ON_EXCEPTION( isolate, Module::Evaluate(isolate, requested_module, stack, dfs_index), Object); DCHECK_GE(requested_module->status(), kEvaluating); DCHECK_NE(requested_module->status(), kErrored); SLOW_DCHECK( // {requested_module} is evaluating iff it's on the {stack}. (requested_module->status() == kEvaluating) == std::count_if(stack->begin(), stack->end(), [&](Handle<Module> m) { return *m == *requested_module; })); if (requested_module->status() == kEvaluating) { // SyntheticModules go straight to kEvaluated so this must be a // SourceTextModule module->set_dfs_ancestor_index( std::min(module->dfs_ancestor_index(), Handle<SourceTextModule>::cast(requested_module) ->dfs_ancestor_index())); } } // Evaluation of module body. Handle<JSFunction> resume( isolate->native_context()->generator_next_internal(), isolate); Handle<Object> result; ASSIGN_RETURN_ON_EXCEPTION( isolate, result, Execution::Call(isolate, resume, generator, 0, nullptr), Object); DCHECK(JSIteratorResult::cast(*result).done().BooleanValue(isolate)); CHECK(MaybeTransitionComponent(isolate, module, stack, kEvaluated)); return handle(JSIteratorResult::cast(*result).value(), isolate); } void SourceTextModule::Reset(Isolate* isolate, Handle<SourceTextModule> module) { Factory* factory = isolate->factory(); DCHECK(module->import_meta().IsTheHole(isolate)); Handle<FixedArray> regular_exports = factory->NewFixedArray(module->regular_exports().length()); Handle<FixedArray> regular_imports = factory->NewFixedArray(module->regular_imports().length()); Handle<FixedArray> requested_modules = factory->NewFixedArray(module->requested_modules().length()); if (module->status() == kInstantiating) { module->set_code(JSFunction::cast(module->code()).shared()); } module->set_regular_exports(*regular_exports); module->set_regular_imports(*regular_imports); module->set_requested_modules(*requested_modules); module->set_dfs_index(-1); module->set_dfs_ancestor_index(-1); } } // namespace internal } // namespace v8