X86: refactor export directive generation

Create a helper function to generate the export directive.  This was previously
duplicated inline to handle export directives for variables and functions.  This
also enables the use of range-based iterators for the generation of the
directive rather than the traditional loops.  NFC.

llvm-svn: 207925
diff --git a/llvm/lib/Target/X86/X86AsmPrinter.h b/llvm/lib/Target/X86/X86AsmPrinter.h
index 3308cc2..e4eef5d 100644
--- a/llvm/lib/Target/X86/X86AsmPrinter.h
+++ b/llvm/lib/Target/X86/X86AsmPrinter.h
@@ -16,13 +16,15 @@
 #include "llvm/Target/TargetMachine.h"
 
 namespace llvm {
-
 class MCStreamer;
+class MCSymbol;
 
 class LLVM_LIBRARY_VISIBILITY X86AsmPrinter : public AsmPrinter {
   const X86Subtarget *Subtarget;
   StackMaps SM;
 
+  void GenerateExportDirective(const MCSymbol *Sym, bool IsData);
+
  public:
   explicit X86AsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
     : AsmPrinter(TM, Streamer), SM(*this) {