//===----- ResourcePriorityQueue.h - A DFA-oriented priority queue -------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the ResourcePriorityQueue class, which is a
// SchedulingPriorityQueue that schedules using DFA state to
// reduce the length of the critical path through the basic block
// on VLIW platforms.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_RESOURCEPRIORITYQUEUE_H
#define LLVM_CODEGEN_RESOURCEPRIORITYQUEUE_H
#include "llvm/CodeGen/ScheduleDAG.h"
namespace llvm {
class DFAPacketizer;
class InstrItineraryData;
class ResourcePriorityQueue;
class SelectionDAGISel;
class TargetInstrInfo;
class TargetRegisterInfo;
/// Sorting functions for the Available queue.
struct resource_sort {
ResourcePriorityQueue *PQ;
explicit resource_sort(ResourcePriorityQueue *pq) : PQ(pq) {}
bool operator()(const SUnit* LHS, const SUnit* RHS) const;
};
class ResourcePriorityQueue : public SchedulingPriorityQueue {
/// SUnits - The SUnits for the current graph.
std::vector<SUnit> *SUnits;
/// NumNodesSolelyBlocking - This vector contains, for every node in the
/// Queue, the number of nodes that the node is the sole unscheduled
/// predecessor for. This is used as a tie-breaker heuristic for better
/// mobility.
std::vector<unsigned> NumNodesSolelyBlocking;
/// Queue - The queue.
std::vector<SUnit*> Queue;
/// RegPressure - Tracking current reg pressure per register class.
///
std::vector<unsigned> RegPressure;
/// RegLimit - Tracking the number of allocatable registers per register
/// class.
std::vector<unsigned> RegLimit;
resource_sort Picker;
const TargetRegisterInfo *TRI;
const TargetLowering *TLI;
const TargetInstrInfo *TII;
const InstrItineraryData* InstrItins;
/// ResourcesModel - Represents VLIW state.
/// Not limited to VLIW targets per say, but assumes
/// definition of DFA by a target.
std::unique_ptr<DFAPacketizer> ResourcesModel;
/// Resource model - packet/bundle model. Purely
/// internal at the time.
std::vector<SUnit*> Packet;
/// Heuristics for estimating register pressure.
unsigned ParallelLiveRanges;
int HorizontalVerticalBalance;
public:
ResourcePriorityQueue(SelectionDAGISel *IS);
bool isBottomUp() const override { return false; }
void initNodes(std::vector<SUnit> &sunits) override;
void addNode(const SUnit *SU) override {
NumNodesSolelyBlocking.resize(SUnits->size(), 0);
}
void updateNode(const SUnit *SU) override {}
void releaseState() override {
SUnits = nullptr;
}
unsigned getLatency(unsigned NodeNum) const {
assert(NodeNum < (*SUnits).size());
return (*SUnits)[NodeNum].getHeight();
}
unsigned getNumSolelyBlockNodes(unsigned NodeNum) const {
assert(NodeNum < NumNodesSolelyBlocking.size());
return NumNodesSolelyBlocking[NodeNum];
}
/// Single cost function reflecting benefit of scheduling SU
/// in the current cycle.
int SUSchedulingCost (SUnit *SU);
/// InitNumRegDefsLeft - Determine the # of regs defined by this node.
///
void initNumRegDefsLeft(SUnit *SU);
int regPressureDelta(SUnit *SU, bool RawPressure = false);
int rawRegPressureDelta (SUnit *SU, unsigned RCId);
bool empty() const override { return Queue.empty(); }
void push(SUnit *U) override;
SUnit *pop() override;
void remove(SUnit *SU) override;
/// scheduledNode - Main resource tracking point.
void scheduledNode(SUnit *SU) override;
bool isResourceAvailable(SUnit *SU);
void reserveResources(SUnit *SU);
private:
void adjustPriorityOfUnscheduledPreds(SUnit *SU);
SUnit *getSingleUnscheduledPred(SUnit *SU);
unsigned numberRCValPredInSU (SUnit *SU, unsigned RCId);
unsigned numberRCValSuccInSU (SUnit *SU, unsigned RCId);
};
}
#endif