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
@@ -123,8 +123,11 @@
   void mangleBlock(const DeclContext *DC, const BlockDecl *BD,
                    raw_ostream &Out);
 
-  void mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *MD, raw_ostream &);
-  void mangleObjCMethodName(const ObjCMethodDecl *MD, raw_ostream &);
+  void mangleObjCMethodName(const ObjCMethodDecl *MD, raw_ostream &OS,
+                            bool includePrefixByte = true,
+                            bool includeCategoryNamespace = true);
+  void mangleObjCMethodNameAsSourceName(const ObjCMethodDecl *MD,
+                                        raw_ostream &);
 
   virtual void mangleStaticGuardVariable(const VarDecl *D, raw_ostream &) = 0;
 
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -2516,7 +2516,7 @@
 }
 
 void CXXNameMangler::mangleObjCMethodName(const ObjCMethodDecl *MD) {
-  Context.mangleObjCMethodName(MD, Out);
+  Context.mangleObjCMethodNameAsSourceName(MD, Out);
 }
 
 static bool isTypeSubstitutable(Qualifiers Quals, const Type *Ty,
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
@@ -175,7 +175,7 @@
   const TargetInfo &TI = Context.getTargetInfo();
   if (CC == CCM_Other || (MCXX && TI.getCXXABI() == TargetCXXABI::Microsoft)) {
     if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
-      mangleObjCMethodName(OMD, Out);
+      mangleObjCMethodNameAsSourceName(OMD, Out);
     else
       mangleCXXName(GD, Out);
     return;
@@ -192,7 +192,7 @@
   if (!MCXX)
     Out << D->getIdentifier()->getName();
   else if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
-    mangleObjCMethodName(OMD, Out);
+    mangleObjCMethodNameAsSourceName(OMD, Out);
   else
     mangleCXXName(GD, Out);
 
@@ -275,7 +275,7 @@
   SmallString<64> Buffer;
   llvm::raw_svector_ostream Stream(Buffer);
   if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(DC)) {
-    mangleObjCMethodName(Method, Stream);
+    mangleObjCMethodNameAsSourceName(Method, Stream);
   } else {
     assert((isa<NamedDecl>(DC) || isa<BlockDecl>(DC)) &&
            "expected a NamedDecl or BlockDecl");
@@ -304,29 +304,38 @@
   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::mangleObjCMethodName(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 (const auto *CID = dyn_cast<ObjCCategoryImplDecl>(MD->getDeclContext())) {
     OS << CID->getClassInterface()->getName();
-    OS << '(' << *CID << ')';
-  } else {
+    if (includeCategoryNamespace) {
+      OS << '(' << *CID << ')';
+    }
+  } else if (const auto *CD =
+                 dyn_cast<ObjCContainerDecl>(MD->getDeclContext())) {
     OS << CD->getName();
+  } else {
+    llvm_unreachable("Unexpected ObjC method decl context");
   }
   OS << ' ';
   MD->getSelector().print(OS);
   OS << ']';
 }
 
-void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
-                                         raw_ostream &Out) {
+void MangleContext::mangleObjCMethodNameAsSourceName(const ObjCMethodDecl *MD,
+                                                     raw_ostream &Out) {
   SmallString<64> Name;
   llvm::raw_svector_ostream OS(Name);
 
-  mangleObjCMethodNameWithoutSize(MD, OS);
+  mangleObjCMethodName(MD, OS, /*includePrefixByte=*/false,
+                       /*includeCategoryNamespace=*/true);
   Out << OS.str().size() << OS.str();
 }
 
@@ -352,7 +361,8 @@
       if (writeFuncOrVarName(VD, FrontendBufOS))
         return true;
     } else if (auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
-      MC->mangleObjCMethodNameWithoutSize(MD, OS);
+      MC->mangleObjCMethodName(MD, OS, /*includePrefixByte=*/false,
+                               /*includeCategoryNamespace=*/true);
       return false;
     } else if (auto *ID = dyn_cast<ObjCInterfaceDecl>(D)) {
       writeObjCClassName(ID, FrontendBufOS);
diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -1323,7 +1323,7 @@
 }
 
 void MicrosoftCXXNameMangler::mangleObjCMethodName(const ObjCMethodDecl *MD) {
-  Context.mangleObjCMethodName(MD, Out);
+  Context.mangleObjCMethodNameAsSourceName(MD, Out);
 }
 
 void MicrosoftCXXNameMangler::mangleTemplateInstantiationName(
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);
@@ -1086,7 +1080,7 @@
 
 public:
   CGObjCCommonMac(CodeGen::CodeGenModule &cgm) :
-    CGObjCRuntime(cgm), VMContext(cgm.getLLVMContext()) { }
+    CGObjCRuntime(cgm), VMContext(cgm.getLLVMContext()), Mangler(cgm.getContext().createMangleContext()) { }
 
   bool isNonFragileABI() const {
     return ObjCABI == 2;
@@ -1127,6 +1121,7 @@
 
 private:
   void fillRunSkipBlockVars(CodeGenModule &CGM, const CGBlockInfo &blockInfo);
+  std::unique_ptr<MangleContext> Mangler;
 };
 
 namespace {
@@ -4008,7 +4003,9 @@
     Method = GenerateDirectMethod(OMD, CD);
   } else {
     SmallString<256> Name;
-    GetNameForMethod(OMD, CD, Name);
+    llvm::raw_svector_ostream OS(Name);
+    Mangler->mangleObjCMethodName(OMD, OS, /*includePrefixByte=*/true,
+                             /*includeCategoryNamespace=*/true);
 
     CodeGenTypes &Types = CGM.getTypes();
     llvm::FunctionType *MethodTy =
@@ -4061,7 +4058,9 @@
     I->second = Fn;
   } else {
     SmallString<256> Name;
-    GetNameForMethod(OMD, CD, Name, /*ignoreCategoryNamespace*/ true);
+    llvm::raw_svector_ostream OS(Name);
+    Mangler->mangleObjCMethodName(OMD, OS, /*includePrefixByte=*/true,
+                             /*includeCategoryNamespace=*/false);
 
     Fn = llvm::Function::Create(MethodTy, llvm::GlobalValue::ExternalLinkage,
                                 Name.str(), &CGM.getModule());
@@ -5715,21 +5714,6 @@
   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();