Set __EXCEPTIONS by checking on darwin's triple.
Patch by Rafael Espindola.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@83209 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index ac7df86..5fa55f2 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -472,7 +472,8 @@
   }
 }
 
-static bool needsExceptions(const ArgList &Args,  types::ID InputType) {
+static bool needsExceptions(const ArgList &Args,  types::ID InputType,
+                            const llvm::Triple &Triple) {
   if (Arg *A = Args.getLastArg(options::OPT_fexceptions,
                                options::OPT_fno_exceptions)) {
     if (A->getOption().matches(options::OPT_fexceptions))
@@ -486,12 +487,16 @@
   case types::TY_ObjCXX: case types::TY_ObjCXXHeader:
   case types::TY_PP_ObjCXX: case types::TY_PP_ObjCXXHeader:
     return true;
+
   case types::TY_ObjC: case types::TY_ObjCHeader:
   case types::TY_PP_ObjC: case types::TY_PP_ObjCHeader:
     if (Args.hasArg(options::OPT_fobjc_nonfragile_abi))
       return true;
-    else
+    if (Triple.getOS() != llvm::Triple::Darwin)
       return false;
+    return (Triple.getDarwinMajorNumber() >= 9 &&
+            Triple.getArch() == llvm::Triple::x86_64);
+
   default:
     return false;
   }
@@ -833,7 +838,7 @@
       CmdArgs.push_back("-fblocks=0");
   }
 
-  if (needsExceptions(Args, InputType))
+  if (needsExceptions(Args, InputType, getToolChain().getTriple()))
     CmdArgs.push_back("-fexceptions");
   else
     CmdArgs.push_back("-fexceptions=0");