[modules] Make handling of module info's regular exports more robust.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 289eace5a26ae20ba33430679d1ea94db2f893ac..2c3860d906ca7f297cdb87b3f346349b8d878582 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -8106,6 +8106,12 @@ class ModuleInfo : public FixedArray {
   inline FixedArray* namespace_imports() const;
   inline FixedArray* regular_imports() const;
 
+  // Accessors for [regular_exports].
+  int RegularExportCount() const;
+  String* RegularExportLocalName(int i) const;
+  int RegularExportCellIndex(int i) const;
+  FixedArray* RegularExportExportNames(int i) const;
+
   static Handle<ModuleInfoEntry> LookupRegularImport(Handle<ModuleInfo> info,
                                                      Handle<String> local_name);
 
@@ -8115,6 +8121,7 @@ class ModuleInfo : public FixedArray {
 
  private:
   friend class Factory;
+  friend class ModuleDescriptor;
   enum {
     kModuleRequestsIndex,
     kSpecialExportsIndex,
@@ -8123,6 +8130,12 @@ class ModuleInfo : public FixedArray {
     kRegularImportsIndex,
     kLength
   };
+  enum {
+    kRegularExportLocalNameOffset,
+    kRegularExportCellIndexOffset,
+    kRegularExportExportNamesOffset,
+    kRegularExportLength
+  };
   DISALLOW_IMPLICIT_CONSTRUCTORS(ModuleInfo);
 };
 // When importing a module namespace (import * as foo from "bar"), a