Porting Hexagon MI Scheduler to the new API.

Change current Hexagon MI scheduler to use new converging scheduler. Integrates DFA resource model into it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163137 91177308-0d34-0410-b5e6-96231b3b80d8
2025-08-05 13:26:55 +00:00 · 2012-09-04 14:49:56 +00:00
parent 67514e9066
commit 3e59040810
11 changed files with 1381 additions and 5 deletions
--- a/lib/Target/Hexagon/HexagonMachineScheduler.h
+++ b/lib/Target/Hexagon/HexagonMachineScheduler.h
@@ -0,0 +1,423 @@
+//===-- HexagonMachineScheduler.h - Custom Hexagon MI scheduler.      ----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Custom Hexagon MI scheduler.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef HEXAGONASMPRINTER_H
+#define HEXAGONASMPRINTER_H
+
+#include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/MachineScheduler.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/RegisterClassInfo.h"
+#include "llvm/CodeGen/RegisterPressure.h"
+#include "llvm/CodeGen/ResourcePriorityQueue.h"
+#include "llvm/CodeGen/ScheduleDAGInstrs.h"
+#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/PriorityQueue.h"
+
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// MachineSchedStrategy - Interface to a machine scheduling algorithm.
+//===----------------------------------------------------------------------===//
+
+namespace llvm {
+class VLIWMachineScheduler;
+
+/// MachineSchedStrategy - Interface used by VLIWMachineScheduler to drive the selected
+/// scheduling algorithm.
+///
+/// If this works well and targets wish to reuse VLIWMachineScheduler, we may expose it
+/// in ScheduleDAGInstrs.h
+class MachineSchedStrategy {
+public:
+  virtual ~MachineSchedStrategy() {}
+
+  /// Initialize the strategy after building the DAG for a new region.
+  virtual void initialize(VLIWMachineScheduler *DAG) = 0;
+
+  /// Pick the next node to schedule, or return NULL. Set IsTopNode to true to
+  /// schedule the node at the top of the unscheduled region. Otherwise it will
+  /// be scheduled at the bottom.
+  virtual SUnit *pickNode(bool &IsTopNode) = 0;
+
+  /// Notify MachineSchedStrategy that VLIWMachineScheduler has scheduled a node.
+  virtual void schedNode(SUnit *SU, bool IsTopNode) = 0;
+
+  /// When all predecessor dependencies have been resolved, free this node for
+  /// top-down scheduling.
+  virtual void releaseTopNode(SUnit *SU) = 0;
+  /// When all successor dependencies have been resolved, free this node for
+  /// bottom-up scheduling.
+  virtual void releaseBottomNode(SUnit *SU) = 0;
+};
+
+//===----------------------------------------------------------------------===//
+// ConvergingVLIWScheduler - Implementation of the standard MachineSchedStrategy.
+//===----------------------------------------------------------------------===//
+
+/// ReadyQueue encapsulates vector of "ready" SUnits with basic convenience
+/// methods for pushing and removing nodes. ReadyQueue's are uniquely identified
+/// by an ID. SUnit::NodeQueueId is a mask of the ReadyQueues the SUnit is in.
+class ReadyQueue {
+  unsigned ID;
+  std::string Name;
+  std::vector<SUnit*> Queue;
+
+public:
+  ReadyQueue(unsigned id, const Twine &name): ID(id), Name(name.str()) {}
+
+  unsigned getID() const { return ID; }
+
+  StringRef getName() const { return Name; }
+
+  // SU is in this queue if it's NodeQueueID is a superset of this ID.
+  bool isInQueue(SUnit *SU) const { return (SU->NodeQueueId & ID); }
+
+  bool empty() const { return Queue.empty(); }
+
+  unsigned size() const { return Queue.size(); }
+
+  typedef std::vector<SUnit*>::iterator iterator;
+
+  iterator begin() { return Queue.begin(); }
+
+  iterator end() { return Queue.end(); }
+
+  iterator find(SUnit *SU) {
+    return std::find(Queue.begin(), Queue.end(), SU);
+  }
+
+  void push(SUnit *SU) {
+    Queue.push_back(SU);
+    SU->NodeQueueId |= ID;
+  }
+
+  void remove(iterator I) {
+    (*I)->NodeQueueId &= ~ID;
+    *I = Queue.back();
+    Queue.pop_back();
+  }
+
+  void dump() {
+    dbgs() << Name << ": ";
+    for (unsigned i = 0, e = Queue.size(); i < e; ++i)
+      dbgs() << Queue[i]->NodeNum << " ";
+    dbgs() << "\n";
+  }
+};
+
+/// ConvergingVLIWScheduler shrinks the unscheduled zone using heuristics to balance
+/// the schedule.
+class ConvergingVLIWScheduler : public MachineSchedStrategy {
+
+  /// Store the state used by ConvergingVLIWScheduler heuristics, required for the
+  /// lifetime of one invocation of pickNode().
+  struct SchedCandidate {
+    // The best SUnit candidate.
+    SUnit *SU;
+
+    // Register pressure values for the best candidate.
+    RegPressureDelta RPDelta;
+
+    // Best scheduling cost.
+    int SCost;
+
+    SchedCandidate(): SU(NULL), SCost(0) {}
+  };
+  /// Represent the type of SchedCandidate found within a single queue.
+  enum CandResult {
+    NoCand, NodeOrder, SingleExcess, SingleCritical, SingleMax, MultiPressure,
+    BestCost};
+
+  /// Each Scheduling boundary is associated with ready queues. It tracks the
+  /// current cycle in whichever direction at has moved, and maintains the state
+  /// of "hazards" and other interlocks at the current cycle.
+  struct SchedBoundary {
+    VLIWMachineScheduler *DAG;
+
+    ReadyQueue Available;
+    ReadyQueue Pending;
+    bool CheckPending;
+
+    ScheduleHazardRecognizer *HazardRec;
+
+    unsigned CurrCycle;
+    unsigned IssueCount;
+
+    /// MinReadyCycle - Cycle of the soonest available instruction.
+    unsigned MinReadyCycle;
+
+    // Remember the greatest min operand latency.
+    unsigned MaxMinLatency;
+
+    /// Pending queues extend the ready queues with the same ID and the
+    /// PendingFlag set.
+    SchedBoundary(unsigned ID, const Twine &Name):
+      DAG(0), Available(ID, Name+".A"),
+      Pending(ID << ConvergingVLIWScheduler::LogMaxQID, Name+".P"),
+      CheckPending(false), HazardRec(0), CurrCycle(0), IssueCount(0),
+      MinReadyCycle(UINT_MAX), MaxMinLatency(0) {}
+
+    ~SchedBoundary() { delete HazardRec; }
+
+    bool isTop() const {
+      return Available.getID() == ConvergingVLIWScheduler::TopQID;
+    }
+
+    bool checkHazard(SUnit *SU);
+
+    void releaseNode(SUnit *SU, unsigned ReadyCycle);
+
+    void bumpCycle();
+
+    void bumpNode(SUnit *SU);
+
+    void releasePending();
+
+    void removeReady(SUnit *SU);
+
+    SUnit *pickOnlyChoice();
+  };
+
+  VLIWMachineScheduler *DAG;
+  const TargetRegisterInfo *TRI;
+
+  // State of the top and bottom scheduled instruction boundaries.
+  SchedBoundary Top;
+  SchedBoundary Bot;
+
+public:
+  /// SUnit::NodeQueueId: 0 (none), 1 (top), 2 (bot), 3 (both)
+  enum {
+    TopQID = 1,
+    BotQID = 2,
+    LogMaxQID = 2
+  };
+
+  ConvergingVLIWScheduler():
+    DAG(0), TRI(0), Top(TopQID, "TopQ"), Bot(BotQID, "BotQ") {}
+
+  virtual void initialize(VLIWMachineScheduler *dag);
+
+  virtual SUnit *pickNode(bool &IsTopNode);
+
+  virtual void schedNode(SUnit *SU, bool IsTopNode);
+
+  virtual void releaseTopNode(SUnit *SU);
+
+  virtual void releaseBottomNode(SUnit *SU);
+
+protected:
+  SUnit *pickNodeBidrectional(bool &IsTopNode);
+
+  int SchedulingCost(ReadyQueue &Q,
+                     SUnit *SU, SchedCandidate &Candidate,
+                     RegPressureDelta &Delta, bool verbose);
+
+  CandResult pickNodeFromQueue(ReadyQueue &Q,
+                               const RegPressureTracker &RPTracker,
+                               SchedCandidate &Candidate);
+#ifndef NDEBUG
+  void traceCandidate(const char *Label, const ReadyQueue &Q, SUnit *SU,
+                      PressureElement P = PressureElement());
+#endif
+};
+
+class VLIWResourceModel {
+  /// ResourcesModel - Represents VLIW state.
+  /// Not limited to VLIW targets per say, but assumes
+  /// definition of DFA by a target.
+  DFAPacketizer *ResourcesModel;
+
+  const InstrItineraryData *InstrItins;
+
+  /// Local packet/bundle model. Purely
+  /// internal to the MI schedulre at the time.
+  std::vector<SUnit*> Packet;
+
+  /// Total packets created.
+  unsigned TotalPackets;
+
+public:
+  VLIWResourceModel(MachineSchedContext *C, const InstrItineraryData *IID) :
+    InstrItins(IID), TotalPackets(0) {
+    const TargetMachine &TM = C->MF->getTarget();
+    ResourcesModel = TM.getInstrInfo()->CreateTargetScheduleState(&TM,NULL);
+
+    // This hard requirement could be relaxed, but for now do not let it proceed.
+    assert(ResourcesModel && "Unimplemented CreateTargetScheduleState.");
+
+    Packet.resize(InstrItins->SchedModel->IssueWidth);
+    Packet.clear();
+    ResourcesModel->clearResources();
+  }
+
+  ~VLIWResourceModel() {
+    delete ResourcesModel;
+  }
+
+  void resetPacketState() {
+    Packet.clear();
+  }
+
+  void resetDFA() {
+    ResourcesModel->clearResources();
+  }
+
+  bool isResourceAvailable(SUnit *SU);
+  void reserveResources(SUnit *SU);
+  unsigned getTotalPackets() const { return TotalPackets; }
+};
+
+class VLIWMachineScheduler : public ScheduleDAGInstrs {
+  /// AA - AliasAnalysis for making memory reference queries.
+  AliasAnalysis *AA;
+
+  RegisterClassInfo *RegClassInfo;
+  MachineSchedStrategy *SchedImpl;
+
+  /// state separatly for top/bottom sectioins.
+  VLIWResourceModel *TopResourceModel;
+  VLIWResourceModel *BotResourceModel;
+
+  MachineBasicBlock::iterator LiveRegionEnd;
+
+  /// Register pressure in this region computed by buildSchedGraph.
+  IntervalPressure RegPressure;
+  RegPressureTracker RPTracker;
+
+  /// List of pressure sets that exceed the target's pressure limit before
+  /// scheduling, listed in increasing set ID order. Each pressure set is paired
+  /// with its max pressure in the currently scheduled regions.
+  std::vector<PressureElement> RegionCriticalPSets;
+
+  /// The top of the unscheduled zone.
+  MachineBasicBlock::iterator CurrentTop;
+  IntervalPressure TopPressure;
+  RegPressureTracker TopRPTracker;
+
+  /// The bottom of the unscheduled zone.
+  MachineBasicBlock::iterator CurrentBottom;
+  IntervalPressure BotPressure;
+  RegPressureTracker BotRPTracker;
+
+#ifndef NDEBUG
+  /// The number of instructions scheduled so far. Used to cut off the
+  /// scheduler at the point determined by misched-cutoff.
+  unsigned NumInstrsScheduled;
+#endif
+
+  /// Total packets in the region.
+  unsigned TotalPackets;
+
+  const MachineLoopInfo *MLI;
+public:
+  VLIWMachineScheduler(MachineSchedContext *C, MachineSchedStrategy *S):
+    ScheduleDAGInstrs(*C->MF, *C->MLI, *C->MDT, /*IsPostRA=*/false, C->LIS),
+    AA(C->AA), RegClassInfo(C->RegClassInfo), SchedImpl(S),
+    RPTracker(RegPressure), CurrentTop(), TopRPTracker(TopPressure),
+    CurrentBottom(), BotRPTracker(BotPressure), MLI(C->MLI) {
+
+    TopResourceModel = new VLIWResourceModel(C, InstrItins);
+    BotResourceModel = new VLIWResourceModel(C, InstrItins);
+
+#ifndef NDEBUG
+    NumInstrsScheduled = 0;
+#endif
+    TotalPackets = 0;
+  }
+
+  virtual ~VLIWMachineScheduler() {
+    delete SchedImpl;
+    delete TopResourceModel;
+    delete BotResourceModel;
+  }
+
+  MachineBasicBlock::iterator top() const { return CurrentTop; }
+  MachineBasicBlock::iterator bottom() const { return CurrentBottom; }
+
+  /// Implement the ScheduleDAGInstrs interface for handling the next scheduling
+  /// region. This covers all instructions in a block, while schedule() may only
+  /// cover a subset.
+  void enterRegion(MachineBasicBlock *bb,
+                   MachineBasicBlock::iterator begin,
+                   MachineBasicBlock::iterator end,
+                   unsigned endcount);
+
+  /// Schedule - This is called back from ScheduleDAGInstrs::Run() when it's
+  /// time to do some work.
+  void schedule();
+
+  unsigned CurCycle;
+
+  /// Get current register pressure for the top scheduled instructions.
+  const IntervalPressure &getTopPressure() const { return TopPressure; }
+  const RegPressureTracker &getTopRPTracker() const { return TopRPTracker; }
+
+  /// Get current register pressure for the bottom scheduled instructions.
+  const IntervalPressure &getBotPressure() const { return BotPressure; }
+  const RegPressureTracker &getBotRPTracker() const { return BotRPTracker; }
+
+  /// Get register pressure for the entire scheduling region before scheduling.
+  const IntervalPressure &getRegPressure() const { return RegPressure; }
+
+  const std::vector<PressureElement> &getRegionCriticalPSets() const {
+    return RegionCriticalPSets;
+  }
+
+  VLIWResourceModel *getTopResourceModel() { return TopResourceModel; };
+  VLIWResourceModel *getBotResourceModel() { return BotResourceModel; };
+
+  /// getIssueWidth - Return the max instructions per scheduling group.
+  unsigned getIssueWidth() const {
+    return (InstrItins && InstrItins->SchedModel)
+      ? InstrItins->SchedModel->IssueWidth : 1;
+  }
+
+  /// getNumMicroOps - Return the number of issue slots required for this MI.
+  unsigned getNumMicroOps(MachineInstr *MI) const {
+    if (!InstrItins) return 1;
+    int UOps = InstrItins->getNumMicroOps(MI->getDesc().getSchedClass());
+    return (UOps >= 0) ? UOps : TII->getNumMicroOps(InstrItins, MI);
+  }
+
+private:
+  void scheduleNodeTopDown(SUnit *SU);
+  void listScheduleTopDown();
+
+  void initRegPressure();
+  void updateScheduledPressure(std::vector<unsigned> NewMaxPressure);
+
+  void moveInstruction(MachineInstr *MI, MachineBasicBlock::iterator InsertPos);
+  bool checkSchedLimit();
+
+  void releaseRoots();
+
+  void releaseSucc(SUnit *SU, SDep *SuccEdge);
+  void releaseSuccessors(SUnit *SU);
+  void releasePred(SUnit *SU, SDep *PredEdge);
+  void releasePredecessors(SUnit *SU);
+
+  void placeDebugValues();
+};
+} // namespace
+
+
+#endif