diff --git a/llvm/include/llvm/Linker/Linker.h b/llvm/include/llvm/Linker/Linker.h
index 679e60582e80..610b1ddf9893 100644
--- a/llvm/include/llvm/Linker/Linker.h
+++ b/llvm/include/llvm/Linker/Linker.h
@@ -82,7 +82,7 @@ public:
   /// function is imported from the source module.
   /// Returns true on error.
   bool linkInModule(Module *Src, unsigned Flags = Flags::None,
-                    FunctionInfoIndex *Index = nullptr,
+                    const FunctionInfoIndex *Index = nullptr,
                     Function *FuncToImport = nullptr);
 
   /// \brief Set the composite to the passed-in module.
diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp
index 7649d13929f4..f97bbe5a8e50 100644
--- a/llvm/lib/Linker/LinkModules.cpp
+++ b/llvm/lib/Linker/LinkModules.cpp
@@ -428,7 +428,7 @@ class ModuleLinker {
 
   /// Function index passed into ModuleLinker for using in function
   /// importing/exporting handling.
-  FunctionInfoIndex *ImportIndex;
+  const FunctionInfoIndex *ImportIndex;
 
   /// Function to import from source module, all other functions are
   /// imported as declarations instead of definitions.
@@ -448,7 +448,7 @@ class ModuleLinker {
 public:
   ModuleLinker(Module *dstM, Linker::IdentifiedStructTypeSet &Set, Module *srcM,
                DiagnosticHandlerFunction DiagnosticHandler, unsigned Flags,
-               FunctionInfoIndex *Index = nullptr,
+               const FunctionInfoIndex *Index = nullptr,
                Function *FuncToImport = nullptr)
       : DstM(dstM), SrcM(srcM), TypeMap(Set),
         ValMaterializer(TypeMap, DstM, LazilyLinkGlobalValues, this),
@@ -2088,7 +2088,8 @@ void Linker::deleteModule() {
   Composite = nullptr;
 }
 
-bool Linker::linkInModule(Module *Src, unsigned Flags, FunctionInfoIndex *Index,
+bool Linker::linkInModule(Module *Src, unsigned Flags,
+                          const FunctionInfoIndex *Index,
                           Function *FuncToImport) {
   ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src,
                          DiagnosticHandler, Flags, Index, FuncToImport);