RDFLiveness.h   [plain text]

//===--- RDFLiveness.h ----------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Recalculate the liveness information given a data flow graph.
// This includes block live-ins and kill flags.

#ifndef RDF_LIVENESS_H
#define RDF_LIVENESS_H

#include "RDFGraph.h"
#include "llvm/ADT/DenseMap.h"
#include <map>

using namespace llvm;

namespace llvm {
  class MachineBasicBlock;
  class MachineFunction;
  class MachineRegisterInfo;
  class TargetRegisterInfo;
  class MachineDominatorTree;
  class MachineDominanceFrontier;
}

namespace rdf {
  struct Liveness {
  public:
    typedef std::map<MachineBasicBlock*,RegisterSet> LiveMapType;
    typedef std::map<RegisterRef,NodeSet> RefMap;

    Liveness(MachineRegisterInfo &mri, const DataFlowGraph &g)
      : DFG(g), TRI(g.getTRI()), MDT(g.getDT()), MDF(g.getDF()),
        RAI(g.getRAI()), MRI(mri), Empty(), Trace(false) {}

    NodeList getAllReachingDefs(RegisterRef RefRR, NodeAddr<RefNode*> RefA,
        bool FullChain = false, const RegisterSet &DefRRs = RegisterSet());
    NodeList getAllReachingDefs(NodeAddr<RefNode*> RefA);

    LiveMapType &getLiveMap() { return LiveMap; }
    const LiveMapType &getLiveMap() const { return LiveMap; }
    const RefMap &getRealUses(NodeId P) const {
      auto F = RealUseMap.find(P);
      return F == RealUseMap.end() ? Empty : F->second;
    }

    void computePhiInfo();
    void computeLiveIns();
    void resetLiveIns();
    void resetKills();
    void resetKills(MachineBasicBlock *B);

    void trace(bool T) { Trace = T; }

  private:
    const DataFlowGraph &DFG;
    const TargetRegisterInfo &TRI;
    const MachineDominatorTree &MDT;
    const MachineDominanceFrontier &MDF;
    const RegisterAliasInfo &RAI;
    MachineRegisterInfo &MRI;
    LiveMapType LiveMap;
    const RefMap Empty;
    bool Trace;

    // Cache of mapping from node ids (for RefNodes) to the containing
    // basic blocks. Not computing it each time for each node reduces
    // the liveness calculation time by a large fraction.
    typedef DenseMap<NodeId,MachineBasicBlock*> NodeBlockMap;
    NodeBlockMap NBMap;

    // Phi information:
    //
    // map: NodeId -> (map: RegisterRef -> NodeSet)
    //      phi id -> (map: register -> set of reached non-phi uses)
    std::map<NodeId, RefMap> RealUseMap;

    // Inverse iterated dominance frontier.
    std::map<MachineBasicBlock*,std::set<MachineBasicBlock*>> IIDF;

    // Live on entry.
    std::map<MachineBasicBlock*,RefMap> PhiLON;

    // Phi uses are considered to be located at the end of the block that
    // they are associated with. The reaching def of a phi use dominates the
    // block that the use corresponds to, but not the block that contains
    // the phi itself. To include these uses in the liveness propagation (up
    // the dominator tree), create a map: block -> set of uses live on exit.
    std::map<MachineBasicBlock*,RefMap> PhiLOX;

    bool isRestricted(NodeAddr<InstrNode*> IA, NodeAddr<RefNode*> RA,
        RegisterRef RR) const;
    RegisterRef getRestrictedRegRef(NodeAddr<RefNode*> RA) const;
    unsigned getPhysReg(RegisterRef RR) const;
    MachineBasicBlock *getBlockWithRef(NodeId RN) const;
    void traverse(MachineBasicBlock *B, RefMap &LiveIn);
    void emptify(RefMap &M);
  };
}

#endif // RDF_LIVENESS_H