Index: include/llvm/Transforms/Utils/ModuleUtils.h
===================================================================
--- include/llvm/Transforms/Utils/ModuleUtils.h
+++ include/llvm/Transforms/Utils/ModuleUtils.h
@@ -20,6 +20,7 @@
 class Function;
 class GlobalValue;
 class GlobalVariable;
+class Constant;
 template <class PtrType> class SmallPtrSetImpl;
 
 /// Append F to the list of global ctors of module M with the given Priority.
@@ -36,6 +37,12 @@
 GlobalVariable *collectUsedGlobalVariables(Module &M,
                                            SmallPtrSetImpl<GlobalValue *> &Set,
                                            bool CompilerUsed);
+
+// Validate the result of Module::getOrInsertFunction called for an interface
+// function of given sanitizer. If the instrumented module defines a function
+// with the same name, their prototypes must match, otherwise
+// getOrInsertFunction returns a bitcast.
+Function *checkInterfaceFunction(Constant *FuncOrBitcast);
 } // End llvm namespace
 
 #endif //  LLVM_TRANSFORMS_UTILS_MODULEUTILS_H
Index: lib/Transforms/Instrumentation/AddressSanitizer.cpp
===================================================================
--- lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -968,18 +968,6 @@
                                    UseCalls, Exp);
 }
 
-// Validate the result of Module::getOrInsertFunction called for an interface
-// function of AddressSanitizer. If the instrumented module defines a function
-// with the same name, their prototypes must match, otherwise
-// getOrInsertFunction returns a bitcast.
-static Function *checkInterfaceFunction(Constant *FuncOrBitcast) {
-  if (isa<Function>(FuncOrBitcast)) return cast<Function>(FuncOrBitcast);
-  FuncOrBitcast->dump();
-  report_fatal_error(
-      "trying to redefine an AddressSanitizer "
-      "interface function");
-}
-
 Instruction *AddressSanitizer::generateCrashCode(Instruction *InsertBefore,
                                                  Value *Addr, bool IsWrite,
                                                  size_t AccessSizeIndex,
Index: lib/Transforms/Instrumentation/SanitizerCoverage.cpp
===================================================================
--- lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -140,16 +140,6 @@
 
 }  // namespace
 
-static Function *checkInterfaceFunction(Constant *FuncOrBitcast) {
-  if (Function *F = dyn_cast<Function>(FuncOrBitcast))
-     return F;
-  std::string Err;
-  raw_string_ostream Stream(Err);
-  Stream << "SanitizerCoverage interface function redefined: "
-         << *FuncOrBitcast;
-  report_fatal_error(Err);
-}
-
 bool SanitizerCoverageModule::runOnModule(Module &M) {
   if (!CoverageLevel) return false;
   C = &(M.getContext());
Index: lib/Transforms/Instrumentation/ThreadSanitizer.cpp
===================================================================
--- lib/Transforms/Instrumentation/ThreadSanitizer.cpp
+++ lib/Transforms/Instrumentation/ThreadSanitizer.cpp
@@ -129,13 +129,6 @@
   return new ThreadSanitizer();
 }
 
-static Function *checkInterfaceFunction(Constant *FuncOrBitcast) {
-  if (Function *F = dyn_cast<Function>(FuncOrBitcast))
-     return F;
-  FuncOrBitcast->dump();
-  report_fatal_error("ThreadSanitizer interface function redefined");
-}
-
 void ThreadSanitizer::initializeCallbacks(Module &M) {
   IRBuilder<> IRB(M.getContext());
   // Initialize the callbacks.
Index: lib/Transforms/Utils/ModuleUtils.cpp
===================================================================
--- lib/Transforms/Utils/ModuleUtils.cpp
+++ lib/Transforms/Utils/ModuleUtils.cpp
@@ -17,6 +17,7 @@
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
@@ -93,3 +94,13 @@
   }
   return GV;
 }
+
+Function *llvm::checkInterfaceFunction(Constant *FuncOrBitcast) {
+  if (isa<Function>(FuncOrBitcast))
+    return cast<Function>(FuncOrBitcast);
+  FuncOrBitcast->dump();
+  std::string Err;
+  raw_string_ostream Stream(Err);
+  Stream << "Sanitizer interface function redefined: " << *FuncOrBitcast;
+  report_fatal_error(Err);
+}