lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.h

   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
  21 namespace 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::Glue 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     const InstrItineraryData *InstrItins;
  40
  41     explicit ScheduleDAGSDNodes(MachineFunction &mf);
  42
  43     virtual ~ScheduleDAGSDNodes() {}
  44
  45     /// Run - perform scheduling.
  46     ///
  47     void Run(SelectionDAG *dag, MachineBasicBlock *bb,
  48              MachineBasicBlock::iterator insertPos);
  49
  50     /// isPassiveNode - Return true if the node is a non-scheduled leaf.
  51     ///
  52     static bool isPassiveNode(SDNode *Node) {
  53       if (isa<ConstantSDNode>(Node))       return true;
  54       if (isa<ConstantFPSDNode>(Node))     return true;
  55       if (isa<RegisterSDNode>(Node))       return true;
  56       if (isa<GlobalAddressSDNode>(Node))  return true;
  57       if (isa<BasicBlockSDNode>(Node))     return true;
  58       if (isa<FrameIndexSDNode>(Node))     return true;
  59       if (isa<ConstantPoolSDNode>(Node))   return true;
  60       if (isa<JumpTableSDNode>(Node))      return true;
  61       if (isa<ExternalSymbolSDNode>(Node)) return true;
  62       if (isa<BlockAddressSDNode>(Node))   return true;
  63       if (Node->getOpcode() == ISD::EntryToken ||
  64           isa<MDNodeSDNode>(Node)) return true;
  65       return false;
  66     }
  67
  68     /// NewSUnit - Creates a new SUnit and return a ptr to it.
  69     ///
  70     SUnit *NewSUnit(SDNode *N);
  71
  72     /// Clone - Creates a clone of the specified SUnit. It does not copy the
  73     /// predecessors / successors info nor the temporary scheduling states.
  74     ///
  75     SUnit *Clone(SUnit *N);
  76
  77     /// BuildSchedGraph - Build the SUnit graph from the selection dag that we
  78     /// are input.  This SUnit graph is similar to the SelectionDAG, but
  79     /// excludes nodes that aren't interesting to scheduling, and represents
  80     /// flagged together nodes with a single SUnit.
  81     virtual void BuildSchedGraph(AliasAnalysis *AA);
  82
  83     /// InitVRegCycleFlag - Set isVRegCycle if this node's single use is
  84     /// CopyToReg and its only active data operands are CopyFromReg within a
  85     /// single block loop.
  86     ///
  87     void InitVRegCycleFlag(SUnit *SU);
  88
  89     /// InitNumRegDefsLeft - Determine the # of regs defined by this node.
  90     ///
  91     void InitNumRegDefsLeft(SUnit *SU);
  92
  93     /// ComputeLatency - Compute node latency.
  94     ///
  95     virtual void ComputeLatency(SUnit *SU);
  96
  97     /// ComputeOperandLatency - Override dependence edge latency using
  98     /// operand use/def information
  99     ///
 100     virtual void ComputeOperandLatency(SUnit *Def, SUnit *Use,
 101                                        SDep& dep) const { }
 102
 103     virtual void ComputeOperandLatency(SDNode *Def, SDNode *Use,
 104                                        unsigned OpIdx, SDep& dep) const;
 105
 106     virtual MachineBasicBlock *EmitSchedule();
 107
 108     /// Schedule - Order nodes according to selected style, filling
 109     /// in the Sequence member.
 110     ///
 111     virtual void Schedule() = 0;
 112
 113     virtual void dumpNode(const SUnit *SU) const;
 114
 115     virtual std::string getGraphNodeLabel(const SUnit *SU) const;
 116
 117     virtual void getCustomGraphFeatures(GraphWriter<ScheduleDAG*> &GW) const;
 118
 119     /// RegDefIter - In place iteration over the values defined by an
 120     /// SUnit. This does not need copies of the iterator or any other STLisms.
 121     /// The iterator creates itself, rather than being provided by the SchedDAG.
 122     class RegDefIter {
 123       const ScheduleDAGSDNodes *SchedDAG;
 124       const SDNode *Node;
 125       unsigned DefIdx;
 126       unsigned NodeNumDefs;
 127       EVT ValueType;
 128     public:
 129       RegDefIter(const SUnit *SU, const ScheduleDAGSDNodes *SD);
 130
 131       bool IsValid() const { return Node != NULL; }
 132
 133       EVT GetValue() const {
 134         assert(IsValid() && "bad iterator");
 135         return ValueType;
 136       }
 137
 138       const SDNode *GetNode() const {
 139         return Node;
 140       }
 141
 142       unsigned GetIdx() const {
 143         return DefIdx-1;
 144       }
 145
 146       void Advance();
 147     private:
 148       void InitNodeNumDefs();
 149     };
 150
 151   private:
 152     /// ClusterNeighboringLoads - Cluster loads from "near" addresses into
 153     /// combined SUnits.
 154     void ClusterNeighboringLoads(SDNode *Node);
 155     /// ClusterNodes - Cluster certain nodes which should be scheduled together.
 156     ///
 157     void ClusterNodes();
 158
 159     /// BuildSchedUnits, AddSchedEdges - Helper functions for BuildSchedGraph.
 160     void BuildSchedUnits();
 161     void AddSchedEdges();
 162   };
 163 }
 164
 165 #endif