Merging r339667:

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r339667 | theraven | 2018-08-14 12:04:36 +0200 (Tue, 14 Aug 2018) | 11 lines

Add a stub mangling for ObjC selectors in the Microsoft ABI.

This mangling is used only for outlined SEH finally blocks, which have
internal linkage.

This fixes the failure of CodeGenObjC/2007-04-03-ObjcEH.m on builds with
expensive checks enabled, on Windows.  This test should probably be
specifying a triple: it currently picks up whatever the host environment
is using.  Unfortunately, I have no idea what it is trying to test,
because it contains no comments and predates Clang having working
Objective-C IR generation.
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llvm-svn: 340437

Author: zmodem

clang/lib/AST/MicrosoftMangle.cpp

@@ -940,8 +940,14 @@ void MicrosoftCXXNameMangler::mangleUnqualifiedName(const NamedDecl *ND,
 
     case DeclarationName::ObjCZeroArgSelector:
     case DeclarationName::ObjCOneArgSelector:
-    case DeclarationName::ObjCMultiArgSelector:
-      llvm_unreachable("Can't mangle Objective-C selector names here!");
+    case DeclarationName::ObjCMultiArgSelector: {
+      // This is reachable only when constructing an outlined SEH finally
+      // block.  Nothing depends on this mangling and it's used only with
+      // functinos with internal linkage.
+      llvm::SmallString<64> Name;
+      mangleSourceName(Name.str());
+      break;
+    }
 
     case DeclarationName::CXXConstructorName:
       if (isStructorDecl(ND)) {