Debug Info: Introduce a DwarfDebug::UseDWARF2Bitfields flag
instead of having DwarfUnit query the debugger tuning options.

Follow-up commmit to r269827.
Thanks to Paul Robinson for pointing this out!

llvm-svn: 269840
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 039a5b9..44a0dc0 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -248,6 +248,9 @@
   /// Whether to use the GNU TLS opcode (instead of the standard opcode).
   bool UseGNUTLSOpcode;
 
+  /// Whether to use DWARF 2 bitfields (instead of the DWARF 4 format).
+  bool UseDWARF2Bitfields;
+
   /// Whether to emit all linkage names, or just abstract subprograms.
   bool UseAllLinkageNames;
 
@@ -482,6 +485,10 @@
   /// standard DW_OP_form_tls_address opcode
   bool useGNUTLSOpcode() const { return UseGNUTLSOpcode; }
 
+  /// Returns whether to use the DWARF2 format for bitfields instyead of the
+  /// DWARF4 format.
+  bool useDWARF2Bitfields() const { return UseDWARF2Bitfields; }
+
   /// \defgroup DebuggerTuning Predicates to tune DWARF for a given debugger.
   ///
   /// Returns whether we are "tuning" for a given debugger.