Add flag to enable Dwarf exception handling on ARM

lib/Target/ARM/ARMSubtarget.h

 //===-- ARMSubtarget.h - Define Subtarget for the ARM ----------*- C++ -*--===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the ARM specific subclass of TargetSubtargetInfo.
@@ skipping 22 matching lines @@
 #include <string>
 
 #define GET_SUBTARGETINFO_HEADER
 #include "ARMGenSubtargetInfo.inc"
 
 namespace llvm {
 class GlobalValue;
 class StringRef;
 class TargetOptions;
 
+extern cl::opt<bool>  EnableARMDwarfEH; // @LOCALMOD
+
 class ARMSubtarget : public ARMGenSubtargetInfo {
 protected:
   enum ARMProcFamilyEnum {
     Others, CortexA5, CortexA7, CortexA8, CortexA9, CortexA12, CortexA15,
     CortexR5, Swift, CortexA53, CortexA57, Krait
   };
   enum ARMProcClassEnum {
     None, AClass, RClass, MClass
   };
 
@@ skipping 323 matching lines @@
   }
 
   // ARM Targets that support EHABI exception handling standard
   // Darwin uses SjLj. Other targets might need more checks.
   bool isTargetEHABICompatible() const {
     return (TargetTriple.getEnvironment() == Triple::EABI ||
             TargetTriple.getEnvironment() == Triple::GNUEABI ||
             TargetTriple.getEnvironment() == Triple::EABIHF ||
             TargetTriple.getEnvironment() == Triple::GNUEABIHF ||
             TargetTriple.getEnvironment() == Triple::Android) &&
-           !isTargetDarwin() && !isTargetWindows();
+        !isTargetDarwin() && !isTargetWindows() && !EnableARMDwarfEH;//@LOCALMOD

[JF, 2014/11/19 19:32:05]

!isTargetNaCl() ?

[Derek Schuff, 2014/11/19 19:56:48]

isTargetNaCl doesn't work for Non-SFI mode, which uses the Linux OS.

but !isTargetNaCl shoud probably be included for SFI NaCl though.

   }
 
   bool isTargetHardFloat() const {
     // FIXME: this is invalid for WindowsCE
     return TargetTriple.getEnvironment() == Triple::GNUEABIHF ||
            TargetTriple.getEnvironment() == Triple::EABIHF ||
            isTargetWindows();
   }
   bool isTargetAndroid() const {
     return TargetTriple.getEnvironment() == Triple::Android;
@@ skipping 56 matching lines @@
 
   /// GVIsIndirectSymbol - true if the GV will be accessed via an indirect
   /// symbol.
   bool GVIsIndirectSymbol(const GlobalValue *GV, Reloc::Model RelocM) const;
 
   bool useInlineJumpTables() const {return UseInlineJumpTables;} // @LOCALMOD
 };
 } // End llvm namespace
 
 #endif  // ARMSUBTARGET_H