#endif
};
+/// Base class for GenericScheduler. This class maintains information about
+/// scheduling candidates based on TargetSchedModel making it easy to implement
+/// heuristics for either preRA or postRA scheduling.
+class GenericSchedulerBase : public MachineSchedStrategy {
+public:
+ /// Represent the type of SchedCandidate found within a single queue.
+ /// pickNodeBidirectional depends on these listed by decreasing priority.
+ enum CandReason {
+ NoCand, PhysRegCopy, RegExcess, RegCritical, Stall, Cluster, Weak, RegMax,
+ ResourceReduce, ResourceDemand, BotHeightReduce, BotPathReduce,
+ TopDepthReduce, TopPathReduce, NextDefUse, NodeOrder};
+
+#ifndef NDEBUG
+ static const char *getReasonStr(GenericSchedulerBase::CandReason Reason);
+#endif
+
+ /// Policy for scheduling the next instruction in the candidate's zone.
+ struct CandPolicy {
+ bool ReduceLatency;
+ unsigned ReduceResIdx;
+ unsigned DemandResIdx;
+
+ CandPolicy(): ReduceLatency(false), ReduceResIdx(0), DemandResIdx(0) {}
+ };
+
+ /// Status of an instruction's critical resource consumption.
+ struct SchedResourceDelta {
+ // Count critical resources in the scheduled region required by SU.
+ unsigned CritResources;
+
+ // Count critical resources from another region consumed by SU.
+ unsigned DemandedResources;
+
+ SchedResourceDelta(): CritResources(0), DemandedResources(0) {}
+
+ bool operator==(const SchedResourceDelta &RHS) const {
+ return CritResources == RHS.CritResources
+ && DemandedResources == RHS.DemandedResources;
+ }
+ bool operator!=(const SchedResourceDelta &RHS) const {
+ return !operator==(RHS);
+ }
+ };
+
+ /// Store the state used by GenericScheduler heuristics, required for the
+ /// lifetime of one invocation of pickNode().
+ struct SchedCandidate {
+ CandPolicy Policy;
+
+ // The best SUnit candidate.
+ SUnit *SU;
+
+ // The reason for this candidate.
+ CandReason Reason;
+
+ // Set of reasons that apply to multiple candidates.
+ uint32_t RepeatReasonSet;
+
+ // Register pressure values for the best candidate.
+ RegPressureDelta RPDelta;
+
+ // Critical resource consumption of the best candidate.
+ SchedResourceDelta ResDelta;
+
+ SchedCandidate(const CandPolicy &policy)
+ : Policy(policy), SU(nullptr), Reason(NoCand), RepeatReasonSet(0) {}
+
+ bool isValid() const { return SU; }
+
+ // Copy the status of another candidate without changing policy.
+ void setBest(SchedCandidate &Best) {
+ assert(Best.Reason != NoCand && "uninitialized Sched candidate");
+ SU = Best.SU;
+ Reason = Best.Reason;
+ RPDelta = Best.RPDelta;
+ ResDelta = Best.ResDelta;
+ }
+
+ bool isRepeat(CandReason R) { return RepeatReasonSet & (1 << R); }
+ void setRepeat(CandReason R) { RepeatReasonSet |= (1 << R); }
+
+ void initResourceDelta(const ScheduleDAGMI *DAG,
+ const TargetSchedModel *SchedModel);
+ };
+
+protected:
+ const MachineSchedContext *Context;
+ const TargetSchedModel *SchedModel;
+ const TargetRegisterInfo *TRI;
+
+ SchedRemainder Rem;
+protected:
+ GenericSchedulerBase(const MachineSchedContext *C):
+ Context(C), SchedModel(nullptr), TRI(nullptr) {}
+
+ void setPolicy(CandPolicy &Policy, bool IsPostRA, SchedBoundary &CurrZone,
+ SchedBoundary *OtherZone);
+
+#ifndef NDEBUG
+ void traceCandidate(const SchedCandidate &Cand);
+#endif
+};
+
+/// GenericScheduler shrinks the unscheduled zone using heuristics to balance
+/// the schedule.
+class GenericScheduler : public GenericSchedulerBase {
+ ScheduleDAGMILive *DAG;
+
+ // State of the top and bottom scheduled instruction boundaries.
+ SchedBoundary Top;
+ SchedBoundary Bot;
+
+ MachineSchedPolicy RegionPolicy;
+public:
+ GenericScheduler(const MachineSchedContext *C):
+ GenericSchedulerBase(C), DAG(nullptr), Top(SchedBoundary::TopQID, "TopQ"),
+ Bot(SchedBoundary::BotQID, "BotQ") {}
+
+ void initPolicy(MachineBasicBlock::iterator Begin,
+ MachineBasicBlock::iterator End,
+ unsigned NumRegionInstrs) override;
+
+ bool shouldTrackPressure() const override {
+ return RegionPolicy.ShouldTrackPressure;
+ }
+
+ void initialize(ScheduleDAGMI *dag) override;
+
+ SUnit *pickNode(bool &IsTopNode) override;
+
+ void schedNode(SUnit *SU, bool IsTopNode) override;
+
+ void releaseTopNode(SUnit *SU) override {
+ Top.releaseTopNode(SU);
+ }
+
+ void releaseBottomNode(SUnit *SU) override {
+ Bot.releaseBottomNode(SU);
+ }
+
+ void registerRoots() override;
+
+protected:
+ void checkAcyclicLatency();
+
+ void tryCandidate(SchedCandidate &Cand,
+ SchedCandidate &TryCand,
+ SchedBoundary &Zone,
+ const RegPressureTracker &RPTracker,
+ RegPressureTracker &TempTracker);
+
+ SUnit *pickNodeBidirectional(bool &IsTopNode);
+
+ void pickNodeFromQueue(SchedBoundary &Zone,
+ const RegPressureTracker &RPTracker,
+ SchedCandidate &Candidate);
+
+ void reschedulePhysRegCopies(SUnit *SU, bool isTop);
+};
+
+/// PostGenericScheduler - Interface to the scheduling algorithm used by
+/// ScheduleDAGMI.
+///
+/// Callbacks from ScheduleDAGMI:
+/// initPolicy -> initialize(DAG) -> registerRoots -> pickNode ...
+class PostGenericScheduler : public GenericSchedulerBase {
+ ScheduleDAGMI *DAG;
+ SchedBoundary Top;
+ SmallVector<SUnit*, 8> BotRoots;
+public:
+ PostGenericScheduler(const MachineSchedContext *C):
+ GenericSchedulerBase(C), Top(SchedBoundary::TopQID, "TopQ") {}
+
+ virtual ~PostGenericScheduler() {}
+
+ void initPolicy(MachineBasicBlock::iterator Begin,
+ MachineBasicBlock::iterator End,
+ unsigned NumRegionInstrs) override {
+ /* no configurable policy */
+ };
+
+ /// PostRA scheduling does not track pressure.
+ bool shouldTrackPressure() const override { return false; }
+
+ void initialize(ScheduleDAGMI *Dag) override;
+
+ void registerRoots() override;
+
+ SUnit *pickNode(bool &IsTopNode) override;
+
+ void scheduleTree(unsigned SubtreeID) override {
+ llvm_unreachable("PostRA scheduler does not support subtree analysis.");
+ }
+
+ void schedNode(SUnit *SU, bool IsTopNode) override;
+
+ void releaseTopNode(SUnit *SU) override {
+ Top.releaseTopNode(SU);
+ }
+
+ // Only called for roots.
+ void releaseBottomNode(SUnit *SU) override {
+ BotRoots.push_back(SU);
+ }
+
+protected:
+ void tryCandidate(SchedCandidate &Cand, SchedCandidate &TryCand);
+
+ void pickNodeFromQueue(SchedCandidate &Cand);
+};
+
} // namespace llvm
#endif
projects / oota-llvm.git / blobdiff