Use export_as for autolinking frameworks

framework module SomeKitCore {
  ...
  export_as SomeKit
}

Given the module above, while generting autolink information during
codegen, clang should to emit '-framework SomeKitCore' only if SomeKit
was not imported in the relevant TU, otherwise it should use '-framework
SomeKit' instead.

rdar://problem/38269782

llvm-svn: 330152
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 9e83250..179f25e 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -5171,6 +5171,7 @@
       break;
 
     case SUBMODULE_LINK_LIBRARY:
+      ModMap.resolveLinkAsDependencies(CurrentModule);
       CurrentModule->LinkLibraries.push_back(
                                          Module::LinkLibrary(Blob, Record[0]));
       break;
@@ -5203,6 +5204,7 @@
 
     case SUBMODULE_EXPORT_AS:
       CurrentModule->ExportAsModule = Blob.str();
+      ModMap.addLinkAsDependency(CurrentModule);
       break;
     }
   }