Swift Calling Convention: add swiftcc.

Differential Revision: http://reviews.llvm.org/D17863

llvm-svn: 265480
diff --git a/llvm/lib/IR/AsmWriter.cpp b/llvm/lib/IR/AsmWriter.cpp
index da92ec2..a6d0018 100644
--- a/llvm/lib/IR/AsmWriter.cpp
+++ b/llvm/lib/IR/AsmWriter.cpp
@@ -315,6 +315,7 @@
   case CallingConv::X86_64_Win64:  Out << "x86_64_win64cc"; break;
   case CallingConv::SPIR_FUNC:     Out << "spir_func"; break;
   case CallingConv::SPIR_KERNEL:   Out << "spir_kernel"; break;
+  case CallingConv::Swift:         Out << "swiftcc"; break;
   case CallingConv::X86_INTR:      Out << "x86_intrcc"; break;
   case CallingConv::HHVM:          Out << "hhvmcc"; break;
   case CallingConv::HHVM_C:        Out << "hhvm_ccc"; break;