[modules] Simplify treatment of empty imports.

src/ast/modules.h

 // Copyright 2012 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.
 
 #ifndef V8_AST_MODULES_H_
 #define V8_AST_MODULES_H_
 
 #include "src/parsing/scanner.h"  // Only for Scanner::Location.
 #include "src/pending-compilation-error-handler.h"
 #include "src/zone/zone-containers.h"
 
 namespace v8 {
 namespace internal {
 
 
 class AstRawString;
 class ModuleInfoEntry;
 
 class ModuleDescriptor : public ZoneObject {
  public:
   explicit ModuleDescriptor(Zone* zone)
       : module_requests_(zone),
         special_exports_(1, zone),
-        special_imports_(1, zone),
+        namespace_imports_(1, zone),
         regular_exports_(zone),
         regular_imports_(zone) {}
 
   // The following Add* methods are high-level convenience functions for use by
   // the parser.
 
   // import x from "foo.js";
   // import {x} from "foo.js";
   // import {x as y} from "foo.js";
   void AddImport(
     const AstRawString* import_name, const AstRawString* local_name,
     const AstRawString* module_request, const Scanner::Location loc,
     Zone* zone);
 
   // import * as x from "foo.js";
   void AddStarImport(
     const AstRawString* local_name, const AstRawString* module_request,
     const Scanner::Location loc, Zone* zone);
 
   // import "foo.js";
   // import {} from "foo.js";
   // export {} from "foo.js";  (sic!)
-  void AddEmptyImport(
-      const AstRawString* module_request, const Scanner::Location loc,
-      Zone* zone);
+  void AddEmptyImport(const AstRawString* module_request);
 
   // export {x};
   // export {x as y};
   // export VariableStatement
   // export Declaration
   // export default ...
   void AddExport(
     const AstRawString* local_name, const AstRawString* export_name,
     const Scanner::Location loc, Zone* zone);
 
@@ skipping 39 matching lines @@
     Handle<ModuleInfoEntry> Serialize(Isolate* isolate) const;
     static Entry* Deserialize(Isolate* isolate, AstValueFactory* avfactory,
                               Handle<ModuleInfoEntry> entry);
   };
 
   // Module requests.
   const ZoneMap<const AstRawString*, int>& module_requests() const {
     return module_requests_;
   }
 
-  // Empty imports and namespace imports.
-  const ZoneList<const Entry*>& special_imports() const {
-    return special_imports_;
+  // Namespace imports.
+  const ZoneList<const Entry*>& namespace_imports() const {
+    return namespace_imports_;
   }
 
   // All the remaining imports, indexed by local name.
   const ZoneMap<const AstRawString*, const Entry*>& regular_imports() const {
     return regular_imports_;
   }
 
   // Star exports and explicitly indirect exports.
   const ZoneList<const Entry*>& special_exports() const {
     return special_exports_;
@@ skipping 22 matching lines @@
   void AddRegularImport(const Entry* entry) {
     DCHECK_NOT_NULL(entry->import_name);
     DCHECK_NOT_NULL(entry->local_name);
     DCHECK_NULL(entry->export_name);
     DCHECK_LE(0, entry->module_request);
     regular_imports_.insert(std::make_pair(entry->local_name, entry));
     // We don't care if there's already an entry for this local name, as in that
     // case we will report an error when declaring the variable.
   }
 
-  void AddSpecialImport(const Entry* entry, Zone* zone) {
+  void AddNamespaceImport(const Entry* entry, Zone* zone) {
+    DCHECK_NULL(entry->import_name);
     DCHECK_NULL(entry->export_name);
+    DCHECK_NOT_NULL(entry->local_name);
     DCHECK_LE(0, entry->module_request);
-    special_imports_.Add(entry, zone);
+    namespace_imports_.Add(entry, zone);
   }
 
   Handle<FixedArray> SerializeRegularExports(Isolate* isolate,
                                              Zone* zone) const;
   void DeserializeRegularExports(Isolate* isolate, AstValueFactory* avfactory,
                                  Handle<FixedArray> data);
 
  private:
   // TODO(neis): Use STL datastructure instead of ZoneList?
   ZoneMap<const AstRawString*, int> module_requests_;
   ZoneList<const Entry*> special_exports_;
-  ZoneList<const Entry*> special_imports_;
+  ZoneList<const Entry*> namespace_imports_;
   ZoneMultimap<const AstRawString*, Entry*> regular_exports_;
   ZoneMap<const AstRawString*, const Entry*> regular_imports_;
 
   // If there are multiple export entries with the same export name, return the
   // last of them (in source order).  Otherwise return nullptr.
   const Entry* FindDuplicateExport(Zone* zone) const;
 
   // Find any implicitly indirect exports and make them explicit.
   //
   // An explicitly indirect export is an export entry arising from an export
@@ skipping 18 matching lines @@
                   .insert(std::make_pair(specifier, module_requests_.size()))
                   .first;
     return it->second;
   }
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_MODULES_H_