1 //=- llvm/CodeGen/ScoreboardHazardRecognizer.h - Schedule Support -*- C++ -*-=//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the ScoreboardHazardRecognizer class, which
11 // encapsulates hazard-avoidance heuristics for scheduling, based on the
12 // scheduling itineraries specified for the target.
14 //===----------------------------------------------------------------------===//
16 #ifndef LLVM_CODEGEN_SCOREBOARDHAZARDRECOGNIZER_H
17 #define LLVM_CODEGEN_SCOREBOARDHAZARDRECOGNIZER_H
19 #include "llvm/CodeGen/ScheduleHazardRecognizer.h"
20 #include "llvm/Support/DataTypes.h"
28 class InstrItineraryData;
29 class TargetInstrDesc;
33 class ScoreboardHazardRecognizer : public ScheduleHazardRecognizer {
34 // Scoreboard to track function unit usage. Scoreboard[0] is a
35 // mask of the FUs in use in the cycle currently being
36 // schedule. Scoreboard[1] is a mask for the next cycle. The
37 // Scoreboard is used as a circular buffer with the current cycle
40 // Scoreboard always counts cycles in forward execution order. If used by a
41 // bottom-up scheduler, then the scoreboard cycles are the inverse of the
42 // scheduler's cycles.
46 // The maximum number of cycles monitored by the Scoreboard. This
47 // value is determined based on the target itineraries to ensure
48 // that all hazards can be tracked.
50 // Indices into the Scoreboard that represent the current cycle.
53 Scoreboard():Data(NULL), Depth(0), Head(0) { }
58 size_t getDepth() const { return Depth; }
59 unsigned& operator[](size_t idx) const {
60 // Depth is expected to be a power-of-2.
61 assert(Depth && !(Depth & (Depth - 1)) &&
62 "Scoreboard was not initialized properly!");
64 return Data[(Head + idx) & (Depth-1)];
67 void reset(size_t d = 1) {
70 Data = new unsigned[Depth];
73 memset(Data, 0, Depth * sizeof(Data[0]));
78 Head = (Head + 1) & (Depth-1);
82 Head = (Head - 1) & (Depth-1);
85 // Print the scoreboard.
90 // Support for tracing ScoreboardHazardRecognizer as a component within
91 // another module. Follows the current thread-unsafe model of tracing.
92 static const char *DebugType;
95 // Itinerary data for the target.
96 const InstrItineraryData *ItinData;
98 const ScheduleDAG *DAG;
100 /// IssueWidth - Max issue per cycle. 0=Unknown.
103 /// IssueCount - Count instructions issued in this cycle.
106 Scoreboard ReservedScoreboard;
107 Scoreboard RequiredScoreboard;
110 ScoreboardHazardRecognizer(const InstrItineraryData *ItinData,
111 const ScheduleDAG *DAG,
112 const char *ParentDebugType = "");
114 /// atIssueLimit - Return true if no more instructions may be issued in this
116 virtual bool atIssueLimit() const;
118 // Stalls provides an cycle offset at which SU will be scheduled. It will be
119 // negative for bottom-up scheduling.
120 virtual HazardType getHazardType(SUnit *SU, int Stalls);
121 virtual void Reset();
122 virtual void EmitInstruction(SUnit *SU);
123 virtual void AdvanceCycle();
124 virtual void RecedeCycle();
129 #endif //!LLVM_CODEGEN_SCOREBOARDHAZARDRECOGNIZER_H