Cherry-pick upstream r237929

lib/AST/ItaniumMangle.cpp

 //===--- ItaniumMangle.cpp - Itanium C++ Name Mangling ----------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // Implements C++ name mangling according to the Itanium C++ ABI,
@@ skipping 2866 matching lines @@
   case Expr::MemberExprClass: {
     const MemberExpr *ME = cast<MemberExpr>(E);
     mangleMemberExpr(ME->getBase(), ME->isArrow(),
                      ME->getQualifier(), nullptr,
                      ME->getMemberDecl()->getDeclName(), Arity);
     break;
   }
 
   case Expr::UnresolvedMemberExprClass: {
     const UnresolvedMemberExpr *ME = cast<UnresolvedMemberExpr>(E);
-    mangleMemberExpr(ME->getBase(), ME->isArrow(),
-                     ME->getQualifier(), nullptr, ME->getMemberName(),
-                     Arity);
+    mangleMemberExpr(ME->isImplicitAccess() ? nullptr : ME->getBase(),
+                     ME->isArrow(), ME->getQualifier(), nullptr,
+                     ME->getMemberName(), Arity);
     if (ME->hasExplicitTemplateArgs())
       mangleTemplateArgs(ME->getExplicitTemplateArgs());
     break;
   }
 
   case Expr::CXXDependentScopeMemberExprClass: {
     const CXXDependentScopeMemberExpr *ME
       = cast<CXXDependentScopeMemberExpr>(E);
-    mangleMemberExpr(ME->getBase(), ME->isArrow(),
-                     ME->getQualifier(), ME->getFirstQualifierFoundInScope(),
+    mangleMemberExpr(ME->isImplicitAccess() ? nullptr : ME->getBase(),
+                     ME->isArrow(), ME->getQualifier(),
+                     ME->getFirstQualifierFoundInScope(),
                      ME->getMember(), Arity);
     if (ME->hasExplicitTemplateArgs())
       mangleTemplateArgs(ME->getExplicitTemplateArgs());
     break;
   }
 
   case Expr::UnresolvedLookupExprClass: {
     const UnresolvedLookupExpr *ULE = cast<UnresolvedLookupExpr>(E);
     mangleUnresolvedName(ULE->getQualifier(), ULE->getName(), Arity);
 
@@ skipping 1165 matching lines @@
 
 void ItaniumMangleContextImpl::mangleStringLiteral(const StringLiteral *, raw_ostream &) {
   llvm_unreachable("Can't mangle string literals");
 }
 
 ItaniumMangleContext *
 ItaniumMangleContext::create(ASTContext &Context, DiagnosticsEngine &Diags) {
   return new ItaniumMangleContextImpl(Context, Diags);
 }