CodeGen: Mark functions used in vtables as unnamed_addr.

This marks virtual function declarations, as well as runtime library functions
__cxa_pure_virtual, __cxa_deleted_virtual and _purecall, as unnamed_addr. This
will allow us to correctly form relative references to them from vtables in
the relative vtable ABI.

Differential Revision: http://reviews.llvm.org/D18071

llvm-svn: 263464
diff --git a/clang/lib/CodeGen/CGVTables.cpp b/clang/lib/CodeGen/CGVTables.cpp
index 953053b..f139e2c 100644
--- a/clang/lib/CodeGen/CGVTables.cpp
+++ b/clang/lib/CodeGen/CGVTables.cpp
@@ -607,6 +607,8 @@
             llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
           StringRef PureCallName = CGM.getCXXABI().GetPureVirtualCallName();
           PureVirtualFn = CGM.CreateRuntimeFunction(Ty, PureCallName);
+          if (auto *F = dyn_cast<llvm::Function>(PureVirtualFn))
+            F->setUnnamedAddr(true);
           PureVirtualFn = llvm::ConstantExpr::getBitCast(PureVirtualFn,
                                                          CGM.Int8PtrTy);
         }
@@ -618,6 +620,8 @@
           StringRef DeletedCallName =
             CGM.getCXXABI().GetDeletedVirtualCallName();
           DeletedVirtualFn = CGM.CreateRuntimeFunction(Ty, DeletedCallName);
+          if (auto *F = dyn_cast<llvm::Function>(DeletedVirtualFn))
+            F->setUnnamedAddr(true);
           DeletedVirtualFn = llvm::ConstantExpr::getBitCast(DeletedVirtualFn,
                                                          CGM.Int8PtrTy);
         }