Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -922,6 +922,7 @@
     PATTERN "*.td"
     PATTERN "*.inc"
     PATTERN "LICENSE.TXT"
+    PATTERN "module.modulemap"
     PATTERN ".svn" EXCLUDE
     )
 
@@ -938,6 +939,10 @@
     PATTERN "config.h" EXCLUDE
     PATTERN ".svn" EXCLUDE
     )
+  install(FILES include/llvm/module.install.modulemap
+    DESTINATION include
+    COMPONENT llvm-headers
+    RENAME "module.extern.modulemap")
 
   # Installing the headers needs to depend on generating any public
   # tablegen'd headers.
Index: include/llvm/module.extern.modulemap
===================================================================
--- /dev/null
+++ include/llvm/module.extern.modulemap
@@ -0,0 +1,4 @@
+module LLVM_Extern_Config_Def {}
+module LLVM_Extern_IR_Attributes_Gen {}
+module LLVM_Extern_IR_Intrinsics_Gen {}
+module LLVM_Extern_Utils_DataTypes {}
Index: include/llvm/module.install.modulemap
===================================================================
--- /dev/null
+++ include/llvm/module.install.modulemap
@@ -0,0 +1,21 @@
+
+module LLVM_Extern_Config_Def {
+ textual header "Config/AsmParsers.def"
+ textual header "Config/AsmPrinters.def"
+ textual header "Config/Disassemblers.def"
+ textual header "Config/Targets.def"
+ export *
+}
+
+module LLVM_Extern_IR_Attributes_Gen {
+  textual header "IR/Attributes.gen"
+}
+
+module LLVM_Extern_IR_Intrinsics_Gen {
+  textual header "IR/Intrinsics.gen"
+}
+
+module LLVM_Extern_Utils_DataTypes {
+  header "Support/DataTypes.h"
+  export *
+}
Index: include/llvm/module.modulemap
===================================================================
--- include/llvm/module.modulemap
+++ include/llvm/module.modulemap
@@ -38,7 +38,12 @@
 }
 
 module LLVM_Bitcode { requires cplusplus umbrella "Bitcode" module * { export * } }
-module LLVM_Config { requires cplusplus umbrella "Config" module * { export * } }
+module LLVM_Config {
+  requires cplusplus
+  umbrella "Config"
+  extern module LLVM_Extern_Config_Def "module.extern.modulemap"
+  module * { export * }
+}
 
 module LLVM_DebugInfo {
   requires cplusplus
@@ -145,6 +150,7 @@
 
   // Attributes.h
   module IR_Argument { header "IR/Argument.h" export * }
+  extern module LLVM_Extern_IR_Attributes_Gen "module.extern.modulemap"
   module IR_Attributes { header "IR/Attributes.h" export * }
   module IR_CallSite { header "IR/CallSite.h" export * }
   module IR_ConstantFolder { header "IR/ConstantFolder.h" export * }
@@ -166,6 +172,7 @@
   module IR_Verifier { header "IR/Verifier.h" export * }
   module IR_InstIterator { header "IR/InstIterator.h" export * }
   module IR_InstVisitor { header "IR/InstVisitor.h" export * }
+  extern module LLVM_Extern_IR_Intricsics_Gen "module.extern.modulemap"
   module IR_Intrinsics { header "IR/Intrinsics.h" export * }
   module IR_IntrinsicInst { header "IR/IntrinsicInst.h" export * }
   module IR_PatternMatch { header "IR/PatternMatch.h" export * }
@@ -232,6 +239,8 @@
   module * { export * }
 }
 
+extern module LLVM_Extern_Utils_DataTypes "module.extern.modulemap"
+
 // A module covering ADT/ and Support/. These are intertwined and
 // codependent, and notionally form a single module.
 module LLVM_Utils {