Clarify which type "Label" refers to (generic vs X86)

src/IceAssembler.h

 //===- subzero/src/IceAssembler.h - Integrated assembler --------*- C++ -*-===//
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // Modified by the Subzero authors.
 //
 //===----------------------------------------------------------------------===//
 //
 //                        The Subzero Code Generator
@@ skipping 231 matching lines @@
 
   /// Add nop padding of a particular width to the current bundle.
   virtual void padWithNop(intptr_t Padding) = 0;
 
   virtual SizeT getBundleAlignLog2Bytes() const = 0;
 
   virtual const char *getAlignDirective() const = 0;
   virtual llvm::ArrayRef<uint8_t> getNonExecBundlePadding() const = 0;
 
   /// Get the label for a CfgNode.
-  virtual Label *getOrCreateCfgNodeLabel(SizeT NodeNumber) = 0;
+  virtual Label *getCfgNodeLabel(SizeT NodeNumber) = 0;
   /// Mark the current text location as the start of a CFG node
   /// (represented by NodeNumber).
   virtual void bindCfgNodeLabel(SizeT NodeNumber) = 0;
 
   virtual bool fixupIsPCRel(FixupKind Kind) const = 0;
 
   // Return a view of all the bytes of code for the current function.
   llvm::StringRef getBufferView() const;
 
   const FixupRefList &fixups() const { return Buffer.fixups(); }
@@ skipping 37 matching lines @@
 protected:
   // Buffer's constructor uses the Allocator, so it needs to appear after it.
   // TODO(jpp): dependencies on construction order are a nice way of shooting
   // yourself in the foot. Fix this.
   AssemblerBuffer Buffer;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEASSEMBLER_H_