SjLj based exception handling unwinding support. This patch is nasty, brutish
and short. Well, it's kinda short. Definitely nasty and brutish.

The front-end generates the register/unregister calls into the SjLj runtime,
call-site indices and landing pad dispatch. The back end fills in the LSDA
with the call-site information provided by the front end. Catch blocks are
not yet implemented.

Built on Darwin and verified no llvm-core "make check" regressions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78625 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index 8249501..c60f9c7 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -229,10 +229,17 @@
 
   // Turn exception handling constructs into something the code generators can
   // handle.
-  if (!getTargetAsmInfo()->doesSupportExceptionHandling())
-    PM.add(createLowerInvokePass(getTargetLowering()));
-  else
+  switch (getTargetAsmInfo()->getExceptionHandlingType())
+  {
+  // SjLj piggy-backs on dwarf for this bit
+  case ExceptionHandling::SjLj:
+  case ExceptionHandling::Dwarf:
     PM.add(createDwarfEHPass(getTargetLowering(), OptLevel==CodeGenOpt::None));
+    break;
+  case ExceptionHandling::None:
+    PM.add(createLowerInvokePass(getTargetLowering()));
+    break;
+  }
 
   PM.add(createGCLoweringPass());