diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
index f66e3ae47e6a..9b9e4bf54222 100644
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -139,6 +139,25 @@ function(add_flag_or_print_warning flag name)
   endif()
 endfunction()
 
+if (LLVM_ENABLE_MODULES)
+  set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
+  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -fmodules -Xclang -fmodules-local-submodule-visibility")
+  # Check that we can build code with modules enabled, and that repeatedly
+  # including <cassert> still manages to respect NDEBUG properly.
+  CHECK_CXX_SOURCE_COMPILES("#undef NDEBUG
+                             #include <cassert>
+                             #define NDEBUG
+                             #include <cassert>
+                             int main() { assert(this code is not compiled); }"
+                             CXX_SUPPORTS_MODULES)
+  set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
+  if (CXX_SUPPORTS_MODULES)
+    append_if(CXX_SUPPORTS_MODULES "-fmodules -Xclang -fmodules-local-submodule-visibility" CMAKE_CXX_FLAGS)
+  else()
+    message(FATAL_ERROR "LLVM_ENABLE_MODULES is not supported by this compiler")
+  endif()
+endif(LLVM_ENABLE_MODULES)
+
 if( LLVM_ENABLE_PIC )
   if( XCODE )
     # Xcode has -mdynamic-no-pic on by default, which overrides -fPIC. I don't
@@ -471,25 +490,6 @@ elseif( LLVM_COMPILER_IS_GCC_COMPATIBLE )
       message(FATAL_ERROR "LLVM requires C++11 support but the '-std=c++11' flag isn't supported.")
     endif()
   endif()
-  if (LLVM_ENABLE_MODULES)
-    set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
-    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -fmodules")
-    # Check that we can build code with modules enabled, and that repeatedly
-    # including <cassert> still manages to respect NDEBUG properly.
-    CHECK_CXX_SOURCE_COMPILES("#undef NDEBUG
-                               #include <cassert>
-                               #define NDEBUG
-                               #include <cassert>
-                               int main() { assert(this code is not compiled); }"
-                               CXX_SUPPORTS_MODULES)
-    set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
-    if (CXX_SUPPORTS_MODULES)
-      append_if(CXX_SUPPORTS_MODULES "-fmodules" CMAKE_C_FLAGS)
-      append_if(CXX_SUPPORTS_MODULES "-fmodules -fcxx-modules" CMAKE_CXX_FLAGS)
-    else()
-      message(FATAL_ERROR "LLVM_ENABLE_MODULES is not supported by this compiler")
-    endif()
-  endif(LLVM_ENABLE_MODULES)
 endif( MSVC )
 
 macro(append_common_sanitizer_flags)
diff --git a/llvm/lib/AsmParser/module.modulemap b/llvm/lib/AsmParser/module.modulemap
deleted file mode 100644
index cc300060b3f5..000000000000
--- a/llvm/lib/AsmParser/module.modulemap
+++ /dev/null
@@ -1 +0,0 @@
-module AsmParser { requires cplusplus umbrella "." module * { export * } }
diff --git a/llvm/lib/Bitcode/module.modulemap b/llvm/lib/Bitcode/module.modulemap
deleted file mode 100644
index 7df1a0a3c721..000000000000
--- a/llvm/lib/Bitcode/module.modulemap
+++ /dev/null
@@ -1 +0,0 @@
-module Bitcode { requires cplusplus umbrella "." module * { export * } }
diff --git a/llvm/lib/CodeGen/module.modulemap b/llvm/lib/CodeGen/module.modulemap
deleted file mode 100644
index d4f68bcc6eed..000000000000
--- a/llvm/lib/CodeGen/module.modulemap
+++ /dev/null
@@ -1 +0,0 @@
-module CodeGen { requires cplusplus umbrella "." module * { export * } }
diff --git a/llvm/lib/DebugInfo/DWARF/module.modulemap b/llvm/lib/DebugInfo/DWARF/module.modulemap
deleted file mode 100644
index c2f624fd4b6c..000000000000
--- a/llvm/lib/DebugInfo/DWARF/module.modulemap
+++ /dev/null
@@ -1 +0,0 @@
-module DebugInfoDWARF { requires cplusplus umbrella "." module * { export * } }
diff --git a/llvm/lib/IR/module.modulemap b/llvm/lib/IR/module.modulemap
deleted file mode 100644
index 9698e9178349..000000000000
--- a/llvm/lib/IR/module.modulemap
+++ /dev/null
@@ -1 +0,0 @@
-module IR { requires cplusplus umbrella "." module * { export * } }
diff --git a/llvm/lib/TableGen/module.modulemap b/llvm/lib/TableGen/module.modulemap
deleted file mode 100644
index 8dac0a22c142..000000000000
--- a/llvm/lib/TableGen/module.modulemap
+++ /dev/null
@@ -1 +0,0 @@
-module TableGen { requires cplusplus umbrella "." module * { export * } }
diff --git a/llvm/utils/TableGen/module.modulemap b/llvm/utils/TableGen/module.modulemap
deleted file mode 100644
index 8871bbfd4a2f..000000000000
--- a/llvm/utils/TableGen/module.modulemap
+++ /dev/null
@@ -1,4 +0,0 @@
-module TableGen {
-  umbrella "."
-  module * { export * }
-}