[modules] Maintain array of cells for imports and local exports.

src/objects.cc

 // Copyright 2015 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.h"
 
 #include <cmath>
 #include <iomanip>
 #include <memory>
 #include <sstream>
@@ skipping 19798 matching lines @@
             zone_allocator<
                 std::pair<const Handle<Module>, UnorderedStringSet*>>(zone)),
         zone_(zone) {}
 
   Zone* zone() const { return zone_; }
 
  private:
   Zone* zone_;
 };
 
+namespace {
+
+int ExportIndex(int cell_index) {
+  DCHECK_EQ(ModuleDescriptor::cell_index_kind(cell_index),
+            ModuleDescriptor::kExport);
+  return cell_index - 1;
+}
+
+int ImportIndex(int cell_index) {
+  DCHECK_EQ(ModuleDescriptor::cell_index_kind(cell_index),
+            ModuleDescriptor::kImport);
+  return -cell_index - 1;
+}
+
+}  // anonymous namespace
+
 void Module::CreateIndirectExport(Handle<Module> module, Handle<String> name,
                                   Handle<ModuleInfoEntry> entry) {
   Isolate* isolate = module->GetIsolate();
   Handle<ObjectHashTable> exports(module->exports(), isolate);
   DCHECK(exports->Lookup(name)->IsTheHole(isolate));
   exports = ObjectHashTable::Put(exports, name, entry);
   module->set_exports(*exports);
 }
 
-void Module::CreateExport(Handle<Module> module, Handle<FixedArray> names) {
+void Module::CreateExport(Handle<Module> module, int index,

[adamk, 2016/11/03 18:30:45]

Curious why you sometimes say "index" and sometimes "cell_index". Is there a
distinction?

[neis, 2016/11/04 10:14:39]

Not here at least. Changed these to cell_index.

+                          Handle<FixedArray> names) {
   DCHECK_LT(0, names->length());
   Isolate* isolate = module->GetIsolate();
+
   Handle<Cell> cell =
       isolate->factory()->NewCell(isolate->factory()->undefined_value());
+  module->regular_exports()->set(ExportIndex(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);
 }
 
-void Module::StoreExport(Handle<Module> module, Handle<String> name,
-                         Handle<Object> value) {
-  Handle<Cell> cell(Cell::cast(module->exports()->Lookup(name)));
-  cell->set_value(*value);
-}
-
-Handle<Object> Module::LoadExport(Handle<Module> module, Handle<String> name) {
+Handle<Object> Module::LoadVariable(Handle<Module> module, int index) {
   Isolate* isolate = module->GetIsolate();
-  Handle<Object> object(module->exports()->Lookup(name), isolate);
+  Handle<Object> object;
+  switch (ModuleDescriptor::cell_index_kind(index)) {
+    case ModuleDescriptor::kImport:
+      object =
+          handle(module->regular_imports()->get(ImportIndex(index)), isolate);
+      break;
+    case ModuleDescriptor::kExport:
+      object =
+          handle(module->regular_exports()->get(ExportIndex(index)), isolate);
+      break;
+    case ModuleDescriptor::kInvalid:
+      UNREACHABLE();
+      break;
+  }
   return handle(Handle<Cell>::cast(object)->value(), isolate);
 }
 
-Handle<Object> Module::LoadImport(Handle<Module> module, Handle<String> name,
-                                  int module_request) {
+void Module::StoreVariable(Handle<Module> module, int index,
+                           Handle<Object> value) {
   Isolate* isolate = module->GetIsolate();
-  Handle<Module> requested_module(
-      Module::cast(module->requested_modules()->get(module_request)), isolate);
-  return Module::LoadExport(requested_module, name);
+  DCHECK_EQ(ModuleDescriptor::cell_index_kind(index),
+            ModuleDescriptor::kExport);
+  Handle<Object> object(module->regular_exports()->get(ExportIndex(index)),
+                        isolate);
+  Handle<Cell>::cast(object)->set_value(*value);
 }
 
 MaybeHandle<Cell> Module::ResolveImport(Handle<Module> module,
                                         Handle<String> name, int module_request,
                                         MessageLocation loc, bool must_resolve,
                                         Module::ResolveSet* resolve_set) {
   Isolate* isolate = module->GetIsolate();
   Handle<Module> requested_module(
       Module::cast(module->requested_modules()->get(module_request)), isolate);
   return Module::ResolveExport(requested_module, name, loc, must_resolve,
@@ skipping 134 matching lines @@
       isolate->factory()->NewFunctionFromSharedFunctionInfo(
           shared,
           handle(Utils::OpenHandle(*context)->native_context(), isolate));
   module->set_code(*function);
   DCHECK(module->instantiated());
 
   Handle<ModuleInfo> module_info(shared->scope_info()->ModuleDescriptorInfo(),
                                  isolate);
 
   // 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(module, export_names);
+    CreateExport(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 ModuleInfoEntry there.  When we later find the correct
   // Cell in the module that actually provides the value, we replace the
   // ModuleInfoEntry 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<ModuleInfoEntry> entry(
@@ skipping 31 matching lines @@
   Handle<FixedArray> regular_imports(module_info->regular_imports(), isolate);
   for (int i = 0, n = regular_imports->length(); i < n; ++i) {
     Handle<ModuleInfoEntry> entry(
         ModuleInfoEntry::cast(regular_imports->get(i)), isolate);
     Handle<String> name(String::cast(entry->import_name()), isolate);
     Handle<Script> script(
         Script::cast(JSFunction::cast(module->code())->shared()->script()),
         isolate);
     MessageLocation loc(script, entry->beg_pos(), entry->end_pos());
     ResolveSet resolve_set(&zone);
-    if (ResolveImport(module, name, entry->module_request(), loc, true,
-                      &resolve_set)
-            .is_null()) {
+    Handle<Cell> cell;
+    if (!ResolveImport(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.
   for (int i = 0, n = special_exports->length(); i < n; ++i) {
     Handle<ModuleInfoEntry> entry(
         ModuleInfoEntry::cast(special_exports->get(i)), isolate);
     Handle<Object> name(entry->export_name(), isolate);
     if (name->IsUndefined(isolate)) continue;  // Star export.
     Handle<Script> script(
         Script::cast(JSFunction::cast(module->code())->shared()->script()),
@@ skipping 169 matching lines @@
         ns, Accessors::ModuleNamespaceEntryInfo(isolate, name, attr))
         .Check();
   }
   JSObject::PreventExtensions(ns, THROW_ON_ERROR).ToChecked();
 
   return ns;
 }
 
 }  // namespace internal
 }  // namespace v8