Long live the exception handling!

This patch fills the last necessary bits to enable exceptions
handling in LLVM. Currently only on x86-32/linux.

In fact, this patch adds necessary intrinsics (and their lowering) which
represent really weird target-specific gcc builtins used inside unwinder.

After corresponding llvm-gcc patch will land (easy) exceptions should be
more or less workable. However, exceptions handling support should not be 
thought as 'finished': I expect many small and not so small glitches
everywhere.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@39855 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index dc23151..9803ab8 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -3369,8 +3369,10 @@
   case ISD::GLOBAL_OFFSET_TABLE: return "GLOBAL_OFFSET_TABLE";
   case ISD::RETURNADDR: return "RETURNADDR";
   case ISD::FRAMEADDR: return "FRAMEADDR";
+  case ISD::FRAME_TO_ARGS_OFFSET: return "FRAME_TO_ARGS_OFFSET";
   case ISD::EXCEPTIONADDR: return "EXCEPTIONADDR";
   case ISD::EHSELECTION: return "EHSELECTION";
+  case ISD::EH_RETURN: return "EH_RETURN";
   case ISD::ConstantPool:  return "ConstantPool";
   case ISD::ExternalSymbol: return "ExternalSymbol";
   case ISD::INTRINSIC_WO_CHAIN: {