Doxygenize the documentation comments

src/IceRegAlloc.h

 //===- subzero/src/IceRegAlloc.h - Linear-scan reg. allocation --*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
-//
-// This file declares the LinearScan data structure used during
-// linear-scan register allocation, which holds the various work
-// queues for the linear-scan algorithm.
-//
+///
+/// \file
+/// This file declares the LinearScan data structure used during
+/// linear-scan register allocation, which holds the various work
+/// queues for the linear-scan algorithm.
+///
 //===----------------------------------------------------------------------===//
 
 #ifndef SUBZERO_SRC_ICEREGALLOC_H
 #define SUBZERO_SRC_ICEREGALLOC_H
 
 #include "IceDefs.h"
 #include "IceTypes.h"
 
 namespace Ice {
 
 class LinearScan {
   LinearScan() = delete;
   LinearScan(const LinearScan &) = delete;
   LinearScan &operator=(const LinearScan &) = delete;
 
 public:
   explicit LinearScan(Cfg *Func) : Func(Func) {}
   void init(RegAllocKind Kind);
   void scan(const llvm::SmallBitVector &RegMask, bool Randomized);
   void dump(Cfg *Func) const;
 
 private:
   typedef std::vector<Variable *> OrderedRanges;
   typedef std::vector<Variable *> UnorderedRanges;
 
   void initForGlobal();
   void initForInfOnly();
-  // Move an item from the From set to the To set.  From[Index] is
-  // pushed onto the end of To[], then the item is efficiently removed
-  // from From[] by effectively swapping it with the last item in
-  // From[] and then popping it from the back.  As such, the caller is
-  // best off iterating over From[] in reverse order to avoid the need
-  // for special handling of the iterator.
+  /// Move an item from the From set to the To set.  From[Index] is
+  /// pushed onto the end of To[], then the item is efficiently removed
+  /// from From[] by effectively swapping it with the last item in
+  /// From[] and then popping it from the back.  As such, the caller is
+  /// best off iterating over From[] in reverse order to avoid the need
+  /// for special handling of the iterator.
   void moveItem(UnorderedRanges &From, SizeT Index, UnorderedRanges &To) {
     To.push_back(From[Index]);
     From[Index] = From.back();
     From.pop_back();
   }
 
   Cfg *const Func;
   OrderedRanges Unhandled;
-  // UnhandledPrecolored is a subset of Unhandled, specially collected
-  // for faster processing.
+  /// UnhandledPrecolored is a subset of Unhandled, specially collected
+  /// for faster processing.
   OrderedRanges UnhandledPrecolored;
   UnorderedRanges Active, Inactive, Handled;
   std::vector<InstNumberT> Kills;
   bool FindPreference = false;
   bool FindOverlap = false;
   // TODO(stichnot): We're not really using FindOverlap yet, but we
   // may want a flavor of register allocation where FindPreference is
   // useful but we didn't want to initialize VMetadata with VMK_All
   // and therefore we can't safely allow overlap.
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEREGALLOC_H