[modules] Split exports into regular and special, store regular ones in a multimap.

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-containers.h"
 
 namespace v8 {
 namespace internal {
 
 
 class AstRawString;
 
 
 class ModuleDescriptor : public ZoneObject {
  public:
   explicit ModuleDescriptor(Zone* zone)
-      : exports_(1, zone), special_imports_(1, zone), regular_imports_(zone) {}
+      : special_exports_(1, zone),
+        special_imports_(1, zone),
+        regular_exports_(zone),
+        regular_imports_(zone) {}
 
   // 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";
@@ skipping 42 matching lines @@
     const AstRawString* module_request;
 
     explicit ModuleEntry(Scanner::Location loc)
         : location(loc),
           export_name(nullptr),
           local_name(nullptr),
           import_name(nullptr),
           module_request(nullptr) {}
   };
 
-  const ZoneList<ModuleEntry*>& exports() const { return exports_; }
-
   // Empty imports and namespace imports.
   const ZoneList<const ModuleEntry*>& special_imports() const {
     return special_imports_;
   }
 
   // All the remaining imports, indexed by local name.
   const ZoneMap<const AstRawString*, const ModuleEntry*>& regular_imports()
       const {
     return regular_imports_;
   }
 
+  // Star exports and explicitly indirect exports.
+  const ZoneList<const ModuleEntry*>& special_exports() const {
+    return special_exports_;
+  }
+
+  // All the remaining exports, indexed by local name.
+  const ZoneMultimap<const AstRawString*, ModuleEntry*>& regular_exports()
+      const {
+    return regular_exports_;
+  }
+
  private:
-  ZoneList<ModuleEntry*> exports_;
+  // TODO(neis): Use STL datastructure instead of ZoneList?
+  ZoneList<const ModuleEntry*> special_exports_;
   ZoneList<const ModuleEntry*> special_imports_;
+  ZoneMultimap<const AstRawString*, ModuleEntry*> regular_exports_;
   ZoneMap<const AstRawString*, const ModuleEntry*> regular_imports_;
 
+  // If there are multiple export entries with the same export name, return one
+  // of them.  Otherwise return nullptr.
+  const ModuleEntry* 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
   // statement of the following form:
   //   export {a as c} from "X";
   // An implicitly indirect export corresponds to
   //   export {b as c};
   // in the presence of an import statement of the form
   //   import {a as b} from "X";
   // This function finds such implicitly indirect export entries and rewrites
   // them by filling in the import name and module request, as well as nulling
   // out the local name.  Effectively, it turns
   //   import {a as b} from "X"; export {b as c};
   // into:
   //   import {a as b} from "X"; export {a as c} from "X";
   // (The import entry is never deleted.)
-  void MakeIndirectExportsExplicit();
+  void MakeIndirectExportsExplicit(Zone* zone);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_MODULES_H_