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"
26 class InstrItineraryData;
30 class ScoreboardHazardRecognizer : public ScheduleHazardRecognizer {
31 // Scoreboard to track function unit usage. Scoreboard[0] is a
32 // mask of the FUs in use in the cycle currently being
33 // schedule. Scoreboard[1] is a mask for the next cycle. The
34 // Scoreboard is used as a circular buffer with the current cycle
37 // Scoreboard always counts cycles in forward execution order. If used by a
38 // bottom-up scheduler, then the scoreboard cycles are the inverse of the
39 // scheduler's cycles.
41 unsigned *Data = nullptr;
43 // The maximum number of cycles monitored by the Scoreboard. This
44 // value is determined based on the target itineraries to ensure
45 // that all hazards can be tracked.
48 // Indices into the Scoreboard that represent the current cycle.
52 Scoreboard() = default;
58 size_t getDepth() const { return Depth; }
60 unsigned& operator[](size_t idx) const {
61 // Depth is expected to be a power-of-2.
62 assert(Depth && !(Depth & (Depth - 1)) &&
63 "Scoreboard was not initialized properly!");
65 return Data[(Head + idx) & (Depth-1)];
68 void reset(size_t d = 1) {
71 Data = new unsigned[Depth];
74 memset(Data, 0, Depth * sizeof(Data[0]));
79 Head = (Head + 1) & (Depth-1);
83 Head = (Head - 1) & (Depth-1);
86 // Print the scoreboard.
90 // Support for tracing ScoreboardHazardRecognizer as a component within
92 const char *DebugType;
94 // Itinerary data for the target.
95 const InstrItineraryData *ItinData;
97 const ScheduleDAG *DAG;
99 /// IssueWidth - Max issue per cycle. 0=Unknown.
100 unsigned IssueWidth = 0;
102 /// IssueCount - Count instructions issued in this cycle.
103 unsigned IssueCount = 0;
105 Scoreboard ReservedScoreboard;
106 Scoreboard RequiredScoreboard;
109 ScoreboardHazardRecognizer(const InstrItineraryData *ItinData,
110 const ScheduleDAG *DAG,
111 const char *ParentDebugType = "");
113 /// atIssueLimit - Return true if no more instructions may be issued in this
115 bool atIssueLimit() const override;
117 // Stalls provides an cycle offset at which SU will be scheduled. It will be
118 // negative for bottom-up scheduling.
119 HazardType getHazardType(SUnit *SU, int Stalls) override;
120 void Reset() override;
121 void EmitInstruction(SUnit *SU) override;
122 void AdvanceCycle() override;
123 void RecedeCycle() override;
126 } // end namespace llvm
128 #endif // LLVM_CODEGEN_SCOREBOARDHAZARDRECOGNIZER_H