Index: lib/AST/MicrosoftMangle.cpp
===================================================================
--- lib/AST/MicrosoftMangle.cpp
+++ lib/AST/MicrosoftMangle.cpp
@@ -3001,6 +3001,11 @@
   msvc_hashing_ostream MHO(Out);
   MicrosoftCXXNameMangler Mangler(*this, MHO);
   Mangler.getStream() << "??_R0";
+  // Obj-C classes are mangled as C++ structs with the same name, but we want to
+  // be able to distinguish a C++ struct X from an Obj-C class X for the
+  // purposes of exception handling, so we add a discriminator.
+  if (T->isObjCObjectPointerType())
+    Mangler.getStream() << "objc.";
   Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
   Mangler.getStream() << "@8";
 }
@@ -3009,6 +3014,9 @@
                                                    raw_ostream &Out) {
   MicrosoftCXXNameMangler Mangler(*this, Out);
   Mangler.getStream() << '.';
+  // See the comment in MicrosoftMangleContextImpl::mangleCXXRTTI.
+  if (T->isObjCObjectPointerType())
+    Mangler.getStream() << "objc.";
   Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
 }
 
Index: test/CodeGenObjCXX/msabi-objc-exceptions-gnustep.mm
===================================================================
--- /dev/null
+++ test/CodeGenObjCXX/msabi-objc-exceptions-gnustep.mm
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -triple i686-windows-msvc -fobjc-runtime=gnustep-2.0 -fexceptions -fobjc-exceptions -emit-llvm -o - %s | FileCheck -check-prefix=X86 %s
+// RUN: %clang_cc1 -triple x86_64-windows-msvc -fobjc-runtime=gnustep-2.0 -fexceptions -fobjc-exceptions -emit-llvm -o - %s | FileCheck -check-prefix=X64 %s
+
+// Ensure we have the .objc discriminator in the RTTI and the RTTI name.
+// X86-DAG: @"??_R0objc.PAUobjc_object@@@8" = linkonce_odr global %{{[^ ]+}} { i8** @"??_7type_info@@6B@", i8* null, [23 x i8] c".objc.PAUobjc_object@@\00" }, comdat
+// X64-DAG: @"??_R0objc.PEAUobjc_object@@@8" = linkonce_odr global %{{[^ ]+}} { i8** @"??_7type_info@@6B@", i8* null, [24 x i8] c".objc.PEAUobjc_object@@\00" }, comdat
+
+@class I;
+// X86-DAG: @"??_R0objc.PAUI@@@8" = linkonce_odr global %{{[^ ]+}} { i8** @"??_7type_info@@6B@", i8* null, [13 x i8] c".objc.PAUI@@\00" }, comdat
+// X64-DAG: @"??_R0objc.PEAUI@@@8" = linkonce_odr global %{{[^ ]+}} { i8** @"??_7type_info@@6B@", i8* null, [14 x i8] c".objc.PEAUI@@\00" }, comdat
+
+void f();
+void g() {
+  @try {
+    f();
+  } @catch (I *) {
+  } @catch (id) {
+  }
+}