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 12 matching lines @@
 
 #ifndef SUBZERO_SRC_ICEASSEMBLER_H
 #define SUBZERO_SRC_ICEASSEMBLER_H
 
 #include "IceDefs.h"
 #include "IceFixups.h"
 #include "IceUtils.h"
 
 namespace Ice {
 
-/// A Label can be in one of three states:
+/// A LabelBase can be in one of three states:
 ///  - Unused.
 ///  - Linked, unplaced and tracking the position of branches to the label.
 ///  - Bound, placed and tracking its position.
-class Label {
-  Label(const Label &) = delete;
-  Label &operator=(const Label &) = delete;
+class LabelBase {

[ascull, 2015/07/31 20:54:54]

Given that ARM and MIPS won't extend this is and that it is not abstract it
would make more sense for this to stay being called Label and for the name to
change in the specialization.

[jvoung (off chromium), 2015/08/03 17:19:21]

Hmm good point about "Base"... ARM and MIPS don't distinguish between Near/Far
so it didn't need the extension.

I wasn't too excited about changing X86 to something other than "Label" if ARM
and MIPS were assemblers/assembler tests were going to simply use "Label" in
their namespace. Then the assemblers would have more similarity, modulo the
namespace. Otherwise, if folks feel strongly and do want to call the X86 version
something else, I'd prefer to come up with a name before I go off and change a
bunch of files =)

For now, I've reverted LabelBase to Label, kept the x86 version as
Ice::X86Internal::Label, and kept the split of getCfgNodeLabel() vs
getOrCreateCfgNodeLabel(), since sometimes getOrCreateCfgNodeLabel()'s return
type is expected to be Ice::X86Internal::Label instead of Ice::Label, while
getCfgNodeLabel() return type is expected to be Ice::Label.

+  LabelBase(const LabelBase &) = delete;
+  LabelBase &operator=(const LabelBase &) = delete;
 
 public:
-  Label() = default;
-  ~Label() = default;
+  LabelBase() = default;
+  ~LabelBase() = default;
 
   virtual void finalCheck() const {
     // Assert if label is being destroyed with unresolved branches pending.
     assert(!isLinked());
   }
 
   /// Returns the position for bound labels (branches that come after this are
   /// considered backward branches). Cannot be used for unused or linked labels.
   intptr_t getPosition() const {
     assert(isBound());
@@ skipping 188 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 LabelBase *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_