Index: clang/include/clang/Frontend/CompilerInstance.h
===================================================================
--- clang/include/clang/Frontend/CompilerInstance.h
+++ clang/include/clang/Frontend/CompilerInstance.h
@@ -698,15 +698,13 @@
   /// The files created by this are usually removed on signal, and, depending
   /// on FrontendOptions, may also use a temporary file (that is, the data is
   /// written to a temporary file which will atomically replace the target
-  /// output on success). If a client (like libclang) needs to disable
-  /// RemoveFileOnSignal, temporary files will be forced on.
+  /// output on success).
   ///
   /// \return - Null on error.
-  std::unique_ptr<raw_pwrite_stream>
-  createDefaultOutputFile(bool Binary = true, StringRef BaseInput = "",
-                          StringRef Extension = "",
-                          bool RemoveFileOnSignal = true,
-                          bool CreateMissingDirectories = false);
+  std::unique_ptr<raw_pwrite_stream> createDefaultOutputFile(
+      bool Binary = true, StringRef BaseInput = "", StringRef Extension = "",
+      bool RemoveFileOnSignal = true, bool CreateMissingDirectories = false,
+      bool ForceUseTemporary = false);
 
   /// Create a new output file, optionally deriving the output path name, and
   /// add it to the list of tracked output files.
Index: clang/lib/Frontend/CompilerInstance.cpp
===================================================================
--- clang/lib/Frontend/CompilerInstance.cpp
+++ clang/lib/Frontend/CompilerInstance.cpp
@@ -736,11 +736,9 @@
   }
 }
 
-std::unique_ptr<raw_pwrite_stream>
-CompilerInstance::createDefaultOutputFile(bool Binary, StringRef InFile,
-                                          StringRef Extension,
-                                          bool RemoveFileOnSignal,
-                                          bool CreateMissingDirectories) {
+std::unique_ptr<raw_pwrite_stream> CompilerInstance::createDefaultOutputFile(
+    bool Binary, StringRef InFile, StringRef Extension, bool RemoveFileOnSignal,
+    bool CreateMissingDirectories, bool ForceUseTemporary) {
   StringRef OutputPath = getFrontendOpts().OutputFile;
   Optional<SmallString<128>> PathStorage;
   if (OutputPath.empty()) {
@@ -753,9 +751,8 @@
     }
   }
 
-  // Force a temporary file if RemoveFileOnSignal was disabled.
   return createOutputFile(OutputPath, Binary, RemoveFileOnSignal,
-                          getFrontendOpts().UseTemporary || !RemoveFileOnSignal,
+                          getFrontendOpts().UseTemporary || ForceUseTemporary,
                           CreateMissingDirectories);
 }
 
Index: clang/lib/Frontend/FrontendActions.cpp
===================================================================
--- clang/lib/Frontend/FrontendActions.cpp
+++ clang/lib/Frontend/FrontendActions.cpp
@@ -218,7 +218,8 @@
   // Because this is exposed via libclang we must disable RemoveFileOnSignal.
   return CI.createDefaultOutputFile(/*Binary=*/true, InFile, /*Extension=*/"",
                                     /*RemoveFileOnSignal=*/false,
-                                    /*CreateMissingDirectories=*/true);
+                                    /*CreateMissingDirectories=*/true,
+                                    /*ForceUseTemporary=*/true);
 }
 
 bool GenerateModuleInterfaceAction::BeginSourceFileAction(