1 files changed, 9 insertions, 5 deletions
diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index 6a261a11548..2b6b78aceec 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -1881,16 +1881,20 @@ void ModuleMapParser::parseHeaderDecl(MMToken::TokenKind LeadingToken,
       Module::Header H = {RelativePathName.str(), File};
       Map.excludeHeader(ActiveModule, H);
     } else {
-      // If there is a builtin counterpart to this file, add it now as a textual
-      // header, so it can be #include_next'd by the wrapper header, and can
-      // receive macros from the wrapper header.
+      // If there is a builtin counterpart to this file, add it now so it can
+      // wrap the system header.
       if (BuiltinFile) {
         // FIXME: Taking the name from the FileEntry is unstable and can give
         // different results depending on how we've previously named that file
         // in this build.
         Module::Header H = { BuiltinFile->getName(), BuiltinFile };
-        Map.addHeader(ActiveModule, H, ModuleMap::ModuleHeaderRole(
-                                           Role | ModuleMap::TextualHeader));
+        Map.addHeader(ActiveModule, H, Role);
+
+        // If we have both a builtin and system version of the file, the
+        // builtin version may want to inject macros into the system header, so
+        // force the system header to be treated as a textual header in this
+        // case.
+        Role = ModuleMap::ModuleHeaderRole(Role | ModuleMap::TextualHeader);
       }
 
       // Record this header.