llvm-6502/lib/Target/Hexagon/HexagonMachineScheduler.h
Andrew Trick 4c60b8a78d mi-sched: Precompute a PressureDiff for each instruction, adjust for liveness later.
Created SUPressureDiffs array to hold the per node PDiff computed during DAG building.

Added a getUpwardPressureDelta API that will soon replace the old
one. Compute PressureDelta here from the precomputed PressureDiffs.

Updating for liveness will come next.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189640 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-30 03:49:48 +00:00

244 lines
6.8 KiB
C++

//===-- 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/ADT/OwningPtr.h"
#include "llvm/ADT/PriorityQueue.h"
#include "llvm/Analysis/AliasAnalysis.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/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetInstrInfo.h"
using namespace llvm;
namespace llvm {
//===----------------------------------------------------------------------===//
// ConvergingVLIWScheduler - Implementation of the standard
// MachineSchedStrategy.
//===----------------------------------------------------------------------===//
class VLIWResourceModel {
/// ResourcesModel - Represents VLIW state.
/// Not limited to VLIW targets per say, but assumes
/// definition of DFA by a target.
DFAPacketizer *ResourcesModel;
const TargetSchedModel *SchedModel;
/// Local packet/bundle model. Purely
/// internal to the MI schedulre at the time.
std::vector<SUnit*> Packet;
/// Total packets created.
unsigned TotalPackets;
public:
VLIWResourceModel(const TargetMachine &TM, const TargetSchedModel *SM) :
SchedModel(SM), TotalPackets(0) {
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(SchedModel->getIssueWidth());
Packet.clear();
ResourcesModel->clearResources();
}
~VLIWResourceModel() {
delete ResourcesModel;
}
void resetPacketState() {
Packet.clear();
}
void resetDFA() {
ResourcesModel->clearResources();
}
void reset() {
Packet.clear();
ResourcesModel->clearResources();
}
bool isResourceAvailable(SUnit *SU);
bool reserveResources(SUnit *SU);
unsigned getTotalPackets() const { return TotalPackets; }
};
/// Extend the standard ScheduleDAGMI to provide more context and override the
/// top-level schedule() driver.
class VLIWMachineScheduler : public ScheduleDAGMI {
public:
VLIWMachineScheduler(MachineSchedContext *C, MachineSchedStrategy *S):
ScheduleDAGMI(C, S) {}
/// Schedule - This is called back from ScheduleDAGInstrs::Run() when it's
/// time to do some work.
virtual void schedule();
/// Perform platform specific DAG postprocessing.
void postprocessDAG();
};
/// 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;
const TargetSchedModel *SchedModel;
ReadyQueue Available;
ReadyQueue Pending;
bool CheckPending;
ScheduleHazardRecognizer *HazardRec;
VLIWResourceModel *ResourceModel;
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), SchedModel(0), Available(ID, Name+".A"),
Pending(ID << ConvergingVLIWScheduler::LogMaxQID, Name+".P"),
CheckPending(false), HazardRec(0), ResourceModel(0),
CurrCycle(0), IssueCount(0),
MinReadyCycle(UINT_MAX), MaxMinLatency(0) {}
~SchedBoundary() {
delete ResourceModel;
delete HazardRec;
}
void init(VLIWMachineScheduler *dag, const TargetSchedModel *smodel) {
DAG = dag;
SchedModel = smodel;
}
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 TargetSchedModel *SchedModel;
// 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), SchedModel(0), Top(TopQID, "TopQ"), Bot(BotQID, "BotQ") {}
virtual void initialize(ScheduleDAGMI *dag);
virtual SUnit *pickNode(bool &IsTopNode);
virtual void schedNode(SUnit *SU, bool IsTopNode);
virtual void releaseTopNode(SUnit *SU);
virtual void releaseBottomNode(SUnit *SU);
unsigned ReportPackets() {
return Top.ResourceModel->getTotalPackets() +
Bot.ResourceModel->getTotalPackets();
}
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,
PressureChange P = PressureChange());
#endif
};
} // namespace
#endif