lib/CodeGen/ExactHazardRecognizer.h

   1 //=- llvm/CodeGen/ExactHazardRecognizer.h - Scheduling Support -*- C++ -*-=//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the ExactHazardRecognizer class, which
  11 // implements hazard-avoidance heuristics for scheduling, based on the
  12 // scheduling itineraries specified for the target.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #ifndef LLVM_CODEGEN_EXACTHAZARDRECOGNIZER_H
  17 #define LLVM_CODEGEN_EXACTHAZARDRECOGNIZER_H
  18
  19 #include "llvm/CodeGen/ScheduleHazardRecognizer.h"
  20 #include "llvm/CodeGen/ScheduleDAG.h"
  21 #include "llvm/Target/TargetInstrItineraries.h"
  22
  23 namespace llvm {
  24   class ExactHazardRecognizer : public ScheduleHazardRecognizer {
  25     // Itinerary data for the target.
  26     const InstrItineraryData &ItinData;
  27
  28     // Scoreboard to track function unit usage. Scoreboard[0] is a
  29     // mask of the FUs in use in the cycle currently being
  30     // schedule. Scoreboard[1] is a mask for the next cycle. The
  31     // Scoreboard is used as a circular buffer with the current cycle
  32     // indicated by ScoreboardHead.
  33     unsigned *Scoreboard;
  34
  35     // The maximum number of cycles monitored by the Scoreboard. This
  36     // value is determined based on the target itineraries to ensure
  37     // that all hazards can be tracked.
  38     unsigned ScoreboardDepth;
  39
  40     // Indices into the Scoreboard that represent the current cycle.
  41     unsigned ScoreboardHead;
  42
  43     // Return the scoreboard index to use for 'offset' cycles in the
  44     // future. 'offset' of 0 returns ScoreboardHead.
  45     unsigned getFutureIndex(unsigned offset);
  46
  47     // Print the scoreboard.
  48     void dumpScoreboard();
  49
  50   public:
  51     ExactHazardRecognizer(const InstrItineraryData &ItinData);
  52     ~ExactHazardRecognizer();
  53
  54     virtual HazardType getHazardType(SUnit *SU);
  55     virtual void Reset();
  56     virtual void EmitInstruction(SUnit *SU);
  57     virtual void AdvanceCycle();
  58   };
  59 }
  60
  61 #endif