Index: llvm/trunk/include/llvm/Bitcode/BitcodeReader.h
===================================================================
--- llvm/trunk/include/llvm/Bitcode/BitcodeReader.h
+++ llvm/trunk/include/llvm/Bitcode/BitcodeReader.h
@@ -152,10 +152,11 @@
 
   /// Parse the module summary index out of an IR file and return the module
   /// summary index object if found, or an empty summary if not. If Path refers
-  /// to an empty file and the -ignore-empty-index-file cl::opt flag is passed
+  /// to an empty file and IgnoreEmptyThinLTOIndexFile is true, then
   /// this function will return nullptr.
   Expected<std::unique_ptr<ModuleSummaryIndex>>
-  getModuleSummaryIndexForFile(StringRef Path);
+  getModuleSummaryIndexForFile(StringRef Path,
+                               bool IgnoreEmptyThinLTOIndexFile = false);
 
   /// isBitcodeWrapper - Return true if the given bytes are the magic bytes
   /// for an LLVM IR bitcode wrapper.
Index: llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
===================================================================
--- llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
+++ llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -93,13 +93,6 @@
     cl::desc(
         "Print the global id for each value when reading the module summary"));
 
-// FIXME: This flag should either be removed or moved to clang as a driver flag.
-static llvm::cl::opt<bool> IgnoreEmptyThinLTOIndexFile(
-    "ignore-empty-index-file", llvm::cl::ZeroOrMore,
-    llvm::cl::desc(
-        "Ignore an empty index file and perform non-ThinLTO compilation"),
-    llvm::cl::init(false));
-
 namespace {
 
 enum {
@@ -5663,7 +5656,8 @@
 }
 
 Expected<std::unique_ptr<ModuleSummaryIndex>>
-llvm::getModuleSummaryIndexForFile(StringRef Path) {
+llvm::getModuleSummaryIndexForFile(StringRef Path,
+                                   bool IgnoreEmptyThinLTOIndexFile) {
   ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
       MemoryBuffer::getFileOrSTDIN(Path);
   if (!FileOrErr)