Subzero: Emit ARM build-attributes in the file scope (as header).

src/IceTargetLowering.cpp

 //===- subzero/src/IceTargetLowering.cpp - Basic lowering implementation --===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the skeleton of the TargetLowering class,
@@ skipping 426 matching lines @@
   if (Target == Target_##X)                                                    \
     return std::unique_ptr<TargetDataLowering>(TargetData##X::create(Ctx));
 #include "llvm/Config/SZTargets.def"
 
   llvm_unreachable("Unsupported target data lowering");
   return nullptr;
 }
 
 TargetDataLowering::~TargetDataLowering() {}
 
+std::unique_ptr<TargetHeaderLowering>
+TargetHeaderLowering::createLowering(GlobalContext *Ctx) {
+  TargetArch Target = Ctx->getFlags().getTargetArch();
+#define SUBZERO_TARGET(X)                                                      \
+  if (Target == Target_##X)                                                    \
+    return std::unique_ptr<TargetHeaderLowering>(TargetHeader##X::create(Ctx));
+#include "llvm/Config/SZTargets.def"
+
+  llvm_unreachable("Unsupported target header lowering");
+  return nullptr;
+}
+
+TargetHeaderLowering::~TargetHeaderLowering() {}
+
 } // end of namespace Ice