Add flag to enable Dwarf exception handling on ARM

lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp

 //===-- ARMMCTargetDesc.cpp - ARM Target Descriptions ---------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file provides ARM specific target descriptions.
 //
 //===----------------------------------------------------------------------===//
 
-#include "ARMMCTargetDesc.h"
 #include "ARMBaseInfo.h"
 #include "ARMMCAsmInfo.h"
 #include "ARMMCTargetDesc.h"
 #include "InstPrinter/ARMInstPrinter.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/MC/MCCodeGenInfo.h"
 #include "llvm/MC/MCELFStreamer.h"
 #include "llvm/MC/MCInstrAnalysis.h"
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCRegisterInfo.h"
@@ skipping 205 matching lines @@
     case llvm::Triple::MSVC:
       MAI = new ARMCOFFMCAsmInfoMicrosoft();
       break;
     default:
       llvm_unreachable("invalid environment");
     }
     break;
   default:
     if (TheTriple.isOSBinFormatMachO())
       MAI = new ARMMCAsmInfoDarwin(TT);
-  // @LOCALMOD-BEGIN
-    else {
-      ARMELFMCAsmInfo *AEMAI = new ARMELFMCAsmInfo(TT);
-      if (TheTriple.isOSNaCl())
-        // NativeClient uses Dwarf exception handling
-        AEMAI->setExceptionsType(ExceptionHandling::DwarfCFI);
-      MAI = AEMAI;
-    }
-  // @LOCALMOD-END
+    else
+      MAI = new ARMELFMCAsmInfo(TT);
     break;
   }
 
   unsigned Reg = MRI.getDwarfRegNum(ARM::SP, true);
   MAI->addInitialFrameState(MCCFIInstruction::createDefCfa(nullptr, Reg, 0));
 
   return MAI;
 }
 
 static MCCodeGenInfo *createARMMCCodeGenInfo(StringRef TT, Reloc::Model RM,
@@ skipping 187 matching lines @@
   // Register the MC relocation info.
   TargetRegistry::RegisterMCRelocationInfo(TheARMLETarget,
                                            createARMMCRelocationInfo);
   TargetRegistry::RegisterMCRelocationInfo(TheARMBETarget,
                                            createARMMCRelocationInfo);
   TargetRegistry::RegisterMCRelocationInfo(TheThumbLETarget,
                                            createARMMCRelocationInfo);
   TargetRegistry::RegisterMCRelocationInfo(TheThumbBETarget,
                                            createARMMCRelocationInfo);
 }