54   // Determine which part of the tag is occupied by the level.
  55   ErgoLevelShift = 8,
  56   ErgoLevelMask = ~((1 << ErgoLevelShift) - 1),
  57 
  58   // ErgoLow is 0 so that we don't have to explicitly or a heuristic
  59   // id with ErgoLow to keep its use simpler.
  60   ErgoLow = 0,
  61   ErgoHigh = 1 << ErgoLevelShift
  62 } ErgoLevel;
  63 
  64 // The available heuristics.
  65 typedef enum {
  66   // Determines which part of the tag is occupied by the heuristic id.
  67   ErgoHeuristicMask = ~ErgoLevelMask,
  68 
  69   ErgoHeapSizing = 0,
  70   ErgoCSetConstruction,
  71   ErgoConcCycles,
  72   ErgoMixedGCs,
  73   ErgoTiming,

  74 
  75   ErgoHeuristicNum
  76 } ErgoHeuristic;
  77 
  78 class G1ErgoVerbose : AllStatic {
  79 private:
  80   // Determines the minimum verboseness level at which records will be
  81   // printed.
  82   static ErgoLevel _level;
  83   // Determines which heuristics are currently enabled.
  84   static bool _enabled[ErgoHeuristicNum];
  85 
  86   static ErgoLevel extract_level(int tag) {
  87     return (ErgoLevel) (tag & ErgoLevelMask);
  88   }
  89 
  90   static ErgoHeuristic extract_heuristic(int tag) {
  91     return (ErgoHeuristic) (tag & ErgoHeuristicMask);
  92   }
  93 

  54   // Determine which part of the tag is occupied by the level.
  55   ErgoLevelShift = 8,
  56   ErgoLevelMask = ~((1 << ErgoLevelShift) - 1),
  57 
  58   // ErgoLow is 0 so that we don't have to explicitly or a heuristic
  59   // id with ErgoLow to keep its use simpler.
  60   ErgoLow = 0,
  61   ErgoHigh = 1 << ErgoLevelShift
  62 } ErgoLevel;
  63 
  64 // The available heuristics.
  65 typedef enum {
  66   // Determines which part of the tag is occupied by the heuristic id.
  67   ErgoHeuristicMask = ~ErgoLevelMask,
  68 
  69   ErgoHeapSizing = 0,
  70   ErgoCSetConstruction,
  71   ErgoConcCycles,
  72   ErgoMixedGCs,
  73   ErgoTiming,
  74   ErgoIHOP,
  75 
  76   ErgoHeuristicNum
  77 } ErgoHeuristic;
  78 
  79 class G1ErgoVerbose : AllStatic {
  80 private:
  81   // Determines the minimum verboseness level at which records will be
  82   // printed.
  83   static ErgoLevel _level;
  84   // Determines which heuristics are currently enabled.
  85   static bool _enabled[ErgoHeuristicNum];
  86 
  87   static ErgoLevel extract_level(int tag) {
  88     return (ErgoLevel) (tag & ErgoLevelMask);
  89   }
  90 
  91   static ErgoHeuristic extract_heuristic(int tag) {
  92     return (ErgoHeuristic) (tag & ErgoHeuristicMask);
  93   }
  94