[libcxxabi] Make new preprocessor guards for SJLJ and ARM_EHABI

[jroelofs]

Summary

This is in preparation to commit ARM EHABI support. Not functional change intended.

[jroelofs]

(forgot to cc cfe-commits)

[jroelofs]

It just occurred to me that these should be called LIBUNWIND_* because they're part of the unwinder, and not actually libcxxabi.

[jroelofs]

Renamed the guards: s/LIBCXXABI/LIBUNWIND/

include/unwind.h

 #define LIBUNWIND_UNAVAIL
 #endif
 
+#if defined(__USING_SJLJ_EXCEPTIONS__)
+#  define LIBUNWIND_SJLJ 1
+#else
+#  define LIBUNWIND_SJLJ 0
+#endif
+
+#if __arm__ && !LIBUNWIND_SJLJ
+#  define LIBUNWIND_ARM_EHABI 1
+#else
+#  define LIBUNWIND_ARM_EHABI 0
+#endif
+
 typedef enum {
   _URC_NO_REASON = 0,
   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,

 //
 // The following are the base functions documented by the C++ ABI
 //
-#if __arm__
+#if LIBUNWIND_SJLJ
 extern _Unwind_Reason_Code
     _Unwind_SjLj_RaiseException(struct _Unwind_Exception *exception_object);
 extern void _Unwind_SjLj_Resume(struct _Unwind_Exception *exception_object);

 extern uintptr_t _Unwind_GetRegionStart(struct _Unwind_Context *context);
 extern uintptr_t
     _Unwind_GetLanguageSpecificData(struct _Unwind_Context *context);
-#if __arm__
+#if LIBUNWIND_SJLJ
 extern _Unwind_Reason_Code
     _Unwind_SjLj_ForcedUnwind(struct _Unwind_Exception *exception_object,
                               _Unwind_Stop_Fn stop, void *stop_parameter);

                          _Unwind_Stop_Fn stop, void *stop_parameter);
 #endif
 
-#if __arm__
+#if LIBUNWIND_SJLJ
 typedef struct _Unwind_FunctionContext *_Unwind_FunctionContext_t;
 extern void _Unwind_SjLj_Register(_Unwind_FunctionContext_t fc);
 extern void _Unwind_SjLj_Unregister(_Unwind_FunctionContext_t fc);

 //
 //  called by __cxa_rethrow().
 //
-#if __arm__
+#if LIBUNWIND_SJLJ
 extern _Unwind_Reason_Code
     _Unwind_SjLj_Resume_or_Rethrow(struct _Unwind_Exception *exception_object);
 #else

src/cxa_exception.cpp

     globals->uncaughtExceptions += 1;   // Not atomically, since globals are thread-local
 
     exception_header->unwindHeader.exception_cleanup = exception_cleanup_func;
-#if __arm__
+#if LIBUNWIND_SJLJ
     _Unwind_SjLj_RaiseException(&exception_header->unwindHeader);
 #else
     _Unwind_RaiseException(&exception_header->unwindHeader);

         //   nothing
         globals->caughtExceptions = 0;
     }
-#if __arm__
+#if LIBUNWIND_SJLJ
     _Unwind_SjLj_RaiseException(&exception_header->unwindHeader);
 #else
     _Unwind_RaiseException(&exception_header->unwindHeader);

         setDependentExceptionClass(&dep_exception_header->unwindHeader);
         __cxa_get_globals()->uncaughtExceptions += 1;
         dep_exception_header->unwindHeader.exception_cleanup = dependent_exception_cleanup;
-#if __arm__
+#if LIBUNWIND_SJLJ
         _Unwind_SjLj_RaiseException(&dep_exception_header->unwindHeader);
 #else
         _Unwind_RaiseException(&dep_exception_header->unwindHeader);