move the lookup to the getRealName()

Author: elsh

Diff for: include/swift/AST/Module.h

@@ -171,9 +171,6 @@ class ModuleDecl
   /// The ABI name of the module, if it differs from the module name.
   mutable Identifier ModuleABIName;
 
-  /// The actual module name for an alias used for this module (if any).
-  mutable Identifier ModuleRealName;
-
 public:
   /// Produces the components of a given module's full name in reverse order.
   ///
@@ -393,12 +390,6 @@ class ModuleDecl
   ///  module if one exists.
   ModuleDecl *getUnderlyingModuleIfOverlay() const;
 
-  /// If a module alias is used, set the corresponding real name on disk,
-  /// which will be used for contents including metadata and mangling.
-  void setRealName(Identifier name) {
-    ModuleRealName = name;
-  }
-
 public:
 
   /// Returns true if this module is an underscored cross import overlay

Diff for: lib/AST/Module.cpp

@@ -476,7 +476,6 @@ ModuleDecl::ModuleDecl(Identifier name, ASTContext &ctx,
   setImplicit();
   setInterfaceType(ModuleType::get(this));
   setAccess(AccessLevel::Public);
-  setRealName(ctx.lookupModuleAlias(name));
 
   Bits.ModuleDecl.StaticLibrary = 0;
   Bits.ModuleDecl.TestingEnabled = 0;
@@ -1565,9 +1564,8 @@ ImportedModule::removeDuplicates(SmallVectorImpl<ImportedModule> &imports) {
 }
 
 Identifier ModuleDecl::getRealName() const {
-    if (!ModuleRealName.empty())
-      return ModuleRealName;
-    return getName();
+  // This will return the real name for an alias (if used) or getName()
+  return getASTContext().lookupModuleAlias(getName());
 }
 
 Identifier ModuleDecl::getABIName() const {