diff --git a/clang/include/clang/AST/Mangle.h b/clang/include/clang/AST/Mangle.h
--- a/clang/include/clang/AST/Mangle.h
+++ b/clang/include/clang/AST/Mangle.h
@@ -123,7 +123,10 @@
   void mangleBlock(const DeclContext *DC, const BlockDecl *BD,
                    raw_ostream &Out);
 
-  void mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *MD, raw_ostream &);
+  void mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *Method,
+                                       raw_ostream &OS,
+                                       bool includePrefixByte = true,
+                                       bool includeCategoryNamespace = true);
   void mangleObjCMethodName(const ObjCMethodDecl *MD, raw_ostream &);
 
   virtual void mangleStaticGuardVariable(const VarDecl *D, raw_ostream &) = 0;
diff --git a/clang/lib/AST/Mangle.cpp b/clang/lib/AST/Mangle.cpp
--- a/clang/lib/AST/Mangle.cpp
+++ b/clang/lib/AST/Mangle.cpp
@@ -304,17 +304,23 @@
   mangleFunctionBlock(*this, Buffer, BD, Out);
 }
 
-void MangleContext::mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *MD,
-                                                    raw_ostream &OS) {
-  const ObjCContainerDecl *CD =
-  dyn_cast<ObjCContainerDecl>(MD->getDeclContext());
-  assert (CD && "Missing container decl in GetNameForMethod");
+void MangleContext::mangleObjCMethodNameWithoutSize(
+    const ObjCMethodDecl *MD, raw_ostream &OS, bool includePrefixByte,
+    bool includeCategoryNamespace) {
+  // \01+[ContainerName(CategoryName) SelectorName]
+  if (includePrefixByte) {
+    OS << '\01';
+  }
   OS << (MD->isInstanceMethod() ? '-' : '+') << '[';
-  if (const ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(CD)) {
+  if (auto *CID = dyn_cast<ObjCCategoryImplDecl>(MD->getDeclContext())) {
     OS << CID->getClassInterface()->getName();
-    OS << '(' << *CID << ')';
-  } else {
+    if (includeCategoryNamespace) {
+      OS << '(' << *CID << ')';
+    }
+  } else if (auto *CD = dyn_cast<ObjCContainerDecl>(MD->getDeclContext())) {
     OS << CD->getName();
+  } else {
+    assert(false && "Unexpected ObjC method decl context");
   }
   OS << ' ';
   MD->getSelector().print(OS);
@@ -326,7 +332,8 @@
   SmallString<64> Name;
   llvm::raw_svector_ostream OS(Name);
 
-  mangleObjCMethodNameWithoutSize(MD, OS);
+  mangleObjCMethodNameWithoutSize(MD, OS, /*includePrefixByte=*/false,
+                                  /*includeCategoryNamespace=*/true);
   Out << OS.str().size() << OS.str();
 }
 
@@ -352,7 +359,8 @@
       if (writeFuncOrVarName(VD, FrontendBufOS))
         return true;
     } else if (auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
-      MC->mangleObjCMethodNameWithoutSize(MD, OS);
+      MC->mangleObjCMethodNameWithoutSize(MD, OS, /*includePrefixByte=*/false,
+                                          /*includeCategoryNamespace=*/true);
       return false;
     } else if (auto *ID = dyn_cast<ObjCInterfaceDecl>(D)) {
       writeObjCClassName(ID, FrontendBufOS);
diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -20,6 +20,7 @@
 #include "clang/AST/Attr.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclObjC.h"
+#include "clang/AST/Mangle.h"
 #include "clang/AST/RecordLayout.h"
 #include "clang/AST/StmtObjC.h"
 #include "clang/Basic/CodeGenOptions.h"
@@ -924,13 +925,6 @@
 
   llvm::StringMap<llvm::GlobalVariable *> NSConstantStringMap;
 
-  /// GetNameForMethod - Return a name for the given method.
-  /// \param[out] NameOut - The return value.
-  void GetNameForMethod(const ObjCMethodDecl *OMD,
-                        const ObjCContainerDecl *CD,
-                        SmallVectorImpl<char> &NameOut,
-                        bool ignoreCategoryNamespace = false);
-
   /// GetMethodVarName - Return a unique constant for the given
   /// selector's name. The return value has type char *.
   llvm::Constant *GetMethodVarName(Selector Sel);
@@ -4008,7 +4002,10 @@
     Method = GenerateDirectMethod(OMD, CD);
   } else {
     SmallString<256> Name;
-    GetNameForMethod(OMD, CD, Name);
+    llvm::raw_svector_ostream OS(Name);
+    const auto &MC = CGM.getContext().createMangleContext();
+    MC->mangleObjCMethodNameWithoutSize(OMD, OS, /*includePrefixByte=*/true,
+                                        /*includeCategoryNamespace=*/true);
 
     CodeGenTypes &Types = CGM.getTypes();
     llvm::FunctionType *MethodTy =
@@ -4061,7 +4058,10 @@
     I->second = Fn;
   } else {
     SmallString<256> Name;
-    GetNameForMethod(OMD, CD, Name, /*ignoreCategoryNamespace*/ true);
+    llvm::raw_svector_ostream OS(Name);
+    const auto &MC = CGM.getContext().createMangleContext();
+    MC->mangleObjCMethodNameWithoutSize(OMD, OS, /*includePrefixByte=*/true,
+                                        /*includeCategoryNamespace=*/false);
 
     Fn = llvm::Function::Create(MethodTy, llvm::GlobalValue::ExternalLinkage,
                                 Name.str(), &CGM.getModule());
@@ -5715,21 +5715,6 @@
   return GetPropertyName(&CGM.getContext().Idents.get(TypeStr));
 }
 
-void CGObjCCommonMac::GetNameForMethod(const ObjCMethodDecl *D,
-                                       const ObjCContainerDecl *CD,
-                                       SmallVectorImpl<char> &Name,
-                                       bool ignoreCategoryNamespace) {
-  llvm::raw_svector_ostream OS(Name);
-  assert (CD && "Missing container decl in GetNameForMethod");
-  OS << '\01' << (D->isInstanceMethod() ? '-' : '+')
-     << '[' << CD->getName();
-  if (!ignoreCategoryNamespace)
-    if (const ObjCCategoryImplDecl *CID =
-        dyn_cast<ObjCCategoryImplDecl>(D->getDeclContext()))
-      OS << '(' << *CID << ')';
-  OS << ' ' << D->getSelector().getAsString() << ']';
-}
-
 void CGObjCMac::FinishModule() {
   EmitModuleInfo();