[PATCH] [ARM64] Enable alignment control option in front-end for ARM64.

This patch is to get "-mno-unaligned-access" and "-munaligned-access"
work in front-end for ARM64 target.

llvm-svn: 208075
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 247d0d8..99d15f72 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -3391,10 +3391,18 @@
                                  options::OPT_munaligned_access)) {
       if (A->getOption().matches(options::OPT_mno_unaligned_access)) {
         CmdArgs.push_back("-backend-option");
-        CmdArgs.push_back("-arm-strict-align");
+        if (getToolChain().getTriple().getArch() == llvm::Triple::arm64 ||
+            getToolChain().getTriple().getArch() == llvm::Triple::arm64_be)
+          CmdArgs.push_back("-arm64-strict-align");
+        else
+          CmdArgs.push_back("-arm-strict-align");
       } else {
         CmdArgs.push_back("-backend-option");
-        CmdArgs.push_back("-arm-no-strict-align");
+        if (getToolChain().getTriple().getArch() == llvm::Triple::arm64 ||
+            getToolChain().getTriple().getArch() == llvm::Triple::arm64_be)
+          CmdArgs.push_back("-arm64-no-strict-align");
+        else
+          CmdArgs.push_back("-arm-no-strict-align");
       }
     }
   }