RDFLiveness.h revision 363496 
1//===- RDFLiveness.h --------------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Recalculate the liveness information given a data flow graph.
10// This includes block live-ins and kill flags.
11
12#ifndef LLVM_LIB_TARGET_HEXAGON_RDFLIVENESS_H
13#define LLVM_LIB_TARGET_HEXAGON_RDFLIVENESS_H
14
15#include "RDFGraph.h"
16#include "RDFRegisters.h"
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/MC/LaneBitmask.h"
19#include <map>
20#include <set>
21#include <utility>
22
23namespace llvm {
24
25class MachineBasicBlock;
26class MachineDominanceFrontier;
27class MachineDominatorTree;
28class MachineRegisterInfo;
29class TargetRegisterInfo;
30
31namespace rdf {
32
33  struct Liveness {
34  public:
35    // This is really a std::map, except that it provides a non-trivial
36    // default constructor to the element accessed via [].
37    struct LiveMapType {
38      LiveMapType(const PhysicalRegisterInfo &pri) : Empty(pri) {}
39
40      RegisterAggr &operator[] (MachineBasicBlock *B) {
41        return Map.emplace(B, Empty).first->second;
42      }
43
44    private:
45      RegisterAggr Empty;
46      std::map<MachineBasicBlock*,RegisterAggr> Map;
47    };
48
49    using NodeRef = std::pair<NodeId, LaneBitmask>;
50    using NodeRefSet = std::set<NodeRef>;
51    // RegisterId in RefMap must be normalized.
52    using RefMap = std::map<RegisterId, NodeRefSet>;
53
54    Liveness(MachineRegisterInfo &mri, const DataFlowGraph &g)
55        : DFG(g), TRI(g.getTRI()), PRI(g.getPRI()), MDT(g.getDT()),
56          MDF(g.getDF()), LiveMap(g.getPRI()), Empty(), NoRegs(g.getPRI()) {}
57
58    NodeList getAllReachingDefs(RegisterRef RefRR, NodeAddr<RefNode*> RefA,
59        bool TopShadows, bool FullChain, const RegisterAggr &DefRRs);
60
61    NodeList getAllReachingDefs(NodeAddr<RefNode*> RefA) {
62      return getAllReachingDefs(RefA.Addr->getRegRef(DFG), RefA, false,
63                                false, NoRegs);
64    }
65
66    NodeList getAllReachingDefs(RegisterRef RefRR, NodeAddr<RefNode*> RefA) {
67      return getAllReachingDefs(RefRR, RefA, false, false, NoRegs);
68    }
69
70    NodeSet getAllReachedUses(RegisterRef RefRR, NodeAddr<DefNode*> DefA,
71        const RegisterAggr &DefRRs);
72
73    NodeSet getAllReachedUses(RegisterRef RefRR, NodeAddr<DefNode*> DefA) {
74      return getAllReachedUses(RefRR, DefA, NoRegs);
75    }
76
77    std::pair<NodeSet,bool> getAllReachingDefsRec(RegisterRef RefRR,
78        NodeAddr<RefNode*> RefA, NodeSet &Visited, const NodeSet &Defs);
79
80    NodeAddr<RefNode*> getNearestAliasedRef(RegisterRef RefRR,
81        NodeAddr<InstrNode*> IA);
82
83    LiveMapType &getLiveMap() { return LiveMap; }
84    const LiveMapType &getLiveMap() const { return LiveMap; }
85
86    const RefMap &getRealUses(NodeId P) const {
87      auto F = RealUseMap.find(P);
88      return F == RealUseMap.end() ? Empty : F->second;
89    }
90
91    void computePhiInfo();
92    void computeLiveIns();
93    void resetLiveIns();
94    void resetKills();
95    void resetKills(MachineBasicBlock *B);
96
97    void trace(bool T) { Trace = T; }
98
99  private:
100    const DataFlowGraph &DFG;
101    const TargetRegisterInfo &TRI;
102    const PhysicalRegisterInfo &PRI;
103    const MachineDominatorTree &MDT;
104    const MachineDominanceFrontier &MDF;
105    LiveMapType LiveMap;
106    const RefMap Empty;
107    const RegisterAggr NoRegs;
108    bool Trace = false;
109
110    // Cache of mapping from node ids (for RefNodes) to the containing
111    // basic blocks. Not computing it each time for each node reduces
112    // the liveness calculation time by a large fraction.
113    using NodeBlockMap = DenseMap<NodeId, MachineBasicBlock *>;
114    NodeBlockMap NBMap;
115
116    // Phi information:
117    //
118    // RealUseMap
119    // map: NodeId -> (map: RegisterId -> NodeRefSet)
120    //      phi id -> (map: register -> set of reached non-phi uses)
121    std::map<NodeId, RefMap> RealUseMap;
122
123    // Inverse iterated dominance frontier.
124    std::map<MachineBasicBlock*,std::set<MachineBasicBlock*>> IIDF;
125
126    // Live on entry.
127    std::map<MachineBasicBlock*,RefMap> PhiLON;
128
129    // Phi uses are considered to be located at the end of the block that
130    // they are associated with. The reaching def of a phi use dominates the
131    // block that the use corresponds to, but not the block that contains
132    // the phi itself. To include these uses in the liveness propagation (up
133    // the dominator tree), create a map: block -> set of uses live on exit.
134    std::map<MachineBasicBlock*,RefMap> PhiLOX;
135
136    MachineBasicBlock *getBlockWithRef(NodeId RN) const;
137    void traverse(MachineBasicBlock *B, RefMap &LiveIn);
138    void emptify(RefMap &M);
139
140    std::pair<NodeSet,bool> getAllReachingDefsRecImpl(RegisterRef RefRR,
141        NodeAddr<RefNode*> RefA, NodeSet &Visited, const NodeSet &Defs,
142        unsigned Nest, unsigned MaxNest);
143  };
144
145  raw_ostream &operator<<(raw_ostream &OS, const Print<Liveness::RefMap> &P);
146
147} // end namespace rdf
148
149} // end namespace llvm
150
151#endif // LLVM_LIB_TARGET_HEXAGON_RDFLIVENESS_H
152