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"
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.
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.
47 // Indices into the Scoreboard that represent the current cycle.
50 Scoreboard():Data(nullptr), Depth(0), Head(0) { }
55 size_t getDepth() const { return Depth; }
56 unsigned& operator[](size_t idx) const {
57 // Depth is expected to be a power-of-2.
58 assert(Depth && !(Depth & (Depth - 1)) &&
59 "Scoreboard was not initialized properly!");
61 return Data[(Head + idx) & (Depth-1)];
64 void reset(size_t d = 1) {
67 Data = new unsigned[Depth];
70 memset(Data, 0, Depth * sizeof(Data[0]));
75 Head = (Head + 1) & (Depth-1);
79 Head = (Head - 1) & (Depth-1);
82 // Print the scoreboard.
87 // Support for tracing ScoreboardHazardRecognizer as a component within
88 // another module. Follows the current thread-unsafe model of tracing.
89 static const char *DebugType;
92 // Itinerary data for the target.
93 const InstrItineraryData *ItinData;
95 const ScheduleDAG *DAG;
97 /// IssueWidth - Max issue per cycle. 0=Unknown.
100 /// IssueCount - Count instructions issued in this cycle.
103 Scoreboard ReservedScoreboard;
104 Scoreboard RequiredScoreboard;
107 ScoreboardHazardRecognizer(const InstrItineraryData *ItinData,
108 const ScheduleDAG *DAG,
109 const char *ParentDebugType = "");
111 /// atIssueLimit - Return true if no more instructions may be issued in this
113 bool atIssueLimit() const override;
115 // Stalls provides an cycle offset at which SU will be scheduled. It will be
116 // negative for bottom-up scheduling.
117 HazardType getHazardType(SUnit *SU, int Stalls) override;
118 void Reset() override;
119 void EmitInstruction(SUnit *SU) override;
120 void AdvanceCycle() override;
121 void RecedeCycle() override;
126 #endif //!LLVM_CODEGEN_SCOREBOARDHAZARDRECOGNIZER_H