1 files changed, 15 insertions, 0 deletions
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 691e96cb11..28a14a2970 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -375,6 +375,21 @@ void Clang::AddPreprocessingOptions(const Driver &D,
       CmdArgs.push_back(A->getValue(Args));
     }
   }
+  
+  // If a module path was provided, pass it along. Otherwise, use a temporary
+  // directory.
+  if (Arg *A = Args.getLastArg(options::OPT_fmodule_cache_path)) {
+    CmdArgs.push_back(A->getValue(Args));
+    A->claim();
+    A->render(Args, CmdArgs);
+  } else {
+    llvm::SmallString<128> DefaultModuleCache;
+    llvm::sys::path::system_temp_directory(/*erasedOnReboot=*/false, 
+                                           DefaultModuleCache);
+    llvm::sys::path::append(DefaultModuleCache, "clang-module-cache");
+    CmdArgs.push_back("-fmodule-cache-path");
+    CmdArgs.push_back(Args.MakeArgString(DefaultModuleCache));
+  }
 }
 
 /// getARMTargetCPU - Get the (LLVM) name of the ARM cpu we are targeting.