Revert "Refactor DebugLocDWARFExpression so it doesn't require access to the"

This reverts commit 230975 to investigate buildbot breakage.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231004 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/AsmPrinter.h

@@ -434,6 +434,29 @@ public:
   /// Get the value for DW_AT_APPLE_isa. Zero if no isa encoding specified.
   virtual unsigned getISAEncoding(const Function *) { return 0; }
 
+  /// Emit a dwarf register operation for describing
+  /// - a small value occupying only part of a register or
+  /// - a register representing only part of a value.
+  void EmitDwarfOpPiece(ByteStreamer &Streamer, unsigned SizeInBits,
+                        unsigned OffsetInBits = 0) const;
+
+
+  /// \brief Emit a partial DWARF register operation.
+  /// \param MLoc             the register
+  /// \param PieceSize        size and
+  /// \param PieceOffset      offset of the piece in bits, if this is one
+  ///                         piece of an aggregate value.
+  ///
+  /// If size and offset is zero an operation for the entire
+  /// register is emitted: Some targets do not provide a DWARF
+  /// register number for every register.  If this is the case, this
+  /// function will attempt to emit a DWARF register by emitting a
+  /// piece of a super-register or by piecing together multiple
+  /// subregisters that alias the register.
+  void EmitDwarfRegOpPiece(ByteStreamer &BS, const MachineLocation &MLoc,
+                           unsigned PieceSize = 0,
+                           unsigned PieceOffset = 0) const;
+
   /// EmitDwarfRegOp - Emit a dwarf register operation.
   virtual void EmitDwarfRegOp(ByteStreamer &BS,
                               const MachineLocation &MLoc) const;