Index: include/clang/AST/DeclCXX.h
===================================================================
--- include/clang/AST/DeclCXX.h
+++ include/clang/AST/DeclCXX.h
@@ -2315,6 +2315,9 @@
   CXXCtorInitializer(ASTContext &Context, TypeSourceInfo *TInfo,
                      SourceLocation L, Expr *Init, SourceLocation R);
 
+  /// \return Unique reproducible object identifier.
+  int64_t getID(const ASTContext &Context) const;
+
   /// Determine whether this initializer is initializing a base class.
   bool isBaseInitializer() const {
     return Initializee.is<TypeSourceInfo*>() && !IsDelegating;
Index: lib/AST/DeclCXX.cpp
===================================================================
--- lib/AST/DeclCXX.cpp
+++ lib/AST/DeclCXX.cpp
@@ -2246,6 +2246,14 @@
     : Initializee(TInfo), Init(Init), LParenLoc(L), RParenLoc(R),
       IsDelegating(true), IsVirtual(false), IsWritten(false), SourceOrder(0) {}
 
+int64_t CXXCtorInitializer::getID(const ASTContext &Context) const {
+  Optional<int64_t> Out = Context.getAllocator().identifyObject(this);
+  assert(Out && "Wrong allocator used");
+  assert(*Out % alignof(CXXCtorInitializer) == 0 &&
+         "Wrong alignment information");
+  return *Out / alignof(CXXCtorInitializer);
+}
+
 TypeLoc CXXCtorInitializer::getBaseClassLoc() const {
   if (isBaseInitializer())
     return Initializee.get<TypeSourceInfo*>()->getTypeLoc();