ScheduleDAGSDNodes.h revision 7abe37e4aee38cc79d91dd069a37d7e91d5bef53 
1//===---- ScheduleDAGSDNodes.h - SDNode Scheduling --------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the ScheduleDAGSDNodes class, which implements
11// scheduling for an SDNode-based dependency graph.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef SCHEDULEDAGSDNODES_H
16#define SCHEDULEDAGSDNODES_H
17
18#include "llvm/CodeGen/ScheduleDAG.h"
19#include "llvm/CodeGen/SelectionDAG.h"
20
21namespace llvm {
22  /// ScheduleDAGSDNodes - A ScheduleDAG for scheduling SDNode-based DAGs.
23  ///
24  /// Edges between SUnits are initially based on edges in the SelectionDAG,
25  /// and additional edges can be added by the schedulers as heuristics.
26  /// SDNodes such as Constants, Registers, and a few others that are not
27  /// interesting to schedulers are not allocated SUnits.
28  ///
29  /// SDNodes with MVT::Flag operands are grouped along with the flagged
30  /// nodes into a single SUnit so that they are scheduled together.
31  ///
32  /// SDNode-based scheduling graphs do not use SDep::Anti or SDep::Output
33  /// edges.  Physical register dependence information is not carried in
34  /// the DAG and must be handled explicitly by schedulers.
35  ///
36  class ScheduleDAGSDNodes : public ScheduleDAG {
37  public:
38    SelectionDAG *DAG;                    // DAG of the current basic block
39
40    explicit ScheduleDAGSDNodes(MachineFunction &mf);
41
42    virtual ~ScheduleDAGSDNodes() {}
43
44    /// Run - perform scheduling.
45    ///
46    void Run(SelectionDAG *dag, MachineBasicBlock *bb,
47             MachineBasicBlock::iterator insertPos);
48
49    /// isPassiveNode - Return true if the node is a non-scheduled leaf.
50    ///
51    static bool isPassiveNode(SDNode *Node) {
52      if (isa<ConstantSDNode>(Node))       return true;
53      if (isa<ConstantFPSDNode>(Node))     return true;
54      if (isa<RegisterSDNode>(Node))       return true;
55      if (isa<GlobalAddressSDNode>(Node))  return true;
56      if (isa<BasicBlockSDNode>(Node))     return true;
57      if (isa<FrameIndexSDNode>(Node))     return true;
58      if (isa<ConstantPoolSDNode>(Node))   return true;
59      if (isa<JumpTableSDNode>(Node))      return true;
60      if (isa<ExternalSymbolSDNode>(Node)) return true;
61      if (isa<BlockAddressSDNode>(Node))   return true;
62      if (Node->getOpcode() == ISD::EntryToken ||
63          isa<MDNodeSDNode>(Node)) return true;
64      return false;
65    }
66
67    /// NewSUnit - Creates a new SUnit and return a ptr to it.
68    ///
69    SUnit *NewSUnit(SDNode *N) {
70#ifndef NDEBUG
71      const SUnit *Addr = 0;
72      if (!SUnits.empty())
73        Addr = &SUnits[0];
74#endif
75      SUnits.push_back(SUnit(N, (unsigned)SUnits.size()));
76      assert((Addr == 0 || Addr == &SUnits[0]) &&
77             "SUnits std::vector reallocated on the fly!");
78      SUnits.back().OrigNode = &SUnits.back();
79      return &SUnits.back();
80    }
81
82    /// Clone - Creates a clone of the specified SUnit. It does not copy the
83    /// predecessors / successors info nor the temporary scheduling states.
84    ///
85    SUnit *Clone(SUnit *N);
86
87    /// BuildSchedGraph - Build the SUnit graph from the selection dag that we
88    /// are input.  This SUnit graph is similar to the SelectionDAG, but
89    /// excludes nodes that aren't interesting to scheduling, and represents
90    /// flagged together nodes with a single SUnit.
91    virtual void BuildSchedGraph(AliasAnalysis *AA);
92
93    /// ComputeLatency - Compute node latency.
94    ///
95    virtual void ComputeLatency(SUnit *SU);
96
97    virtual MachineBasicBlock *
98    EmitSchedule(DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM);
99
100    /// Schedule - Order nodes according to selected style, filling
101    /// in the Sequence member.
102    ///
103    virtual void Schedule() = 0;
104
105    virtual void dumpNode(const SUnit *SU) const;
106
107    virtual std::string getGraphNodeLabel(const SUnit *SU) const;
108
109    virtual void getCustomGraphFeatures(GraphWriter<ScheduleDAG*> &GW) const;
110
111  private:
112    /// ClusterNeighboringLoads - Cluster loads from "near" addresses into
113    /// combined SUnits.
114    void ClusterNeighboringLoads();
115
116    /// BuildSchedUnits, AddSchedEdges - Helper functions for BuildSchedGraph.
117    void BuildSchedUnits();
118    void AddSchedEdges();
119  };
120}
121
122#endif
123