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//===---- llvm/CodeGen/ScheduleDAGSDNodes.h - SDNode Scheduling -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the ScheduleDAGSDNodes class, which implements
// scheduling for an SDNode-based dependency graph.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_SCHEDULEDAGSDNODES_H
#define LLVM_CODEGEN_SCHEDULEDAGSDNODES_H
#include "llvm/CodeGen/ScheduleDAG.h"
#include "llvm/CodeGen/SelectionDAG.h"
namespace llvm {
/// HazardRecognizer - This determines whether or not an instruction can be
/// issued this cycle, and whether or not a noop needs to be inserted to handle
/// the hazard.
class HazardRecognizer {
public:
virtual ~HazardRecognizer();
enum HazardType {
NoHazard, // This instruction can be emitted at this cycle.
Hazard, // This instruction can't be emitted at this cycle.
NoopHazard // This instruction can't be emitted, and needs noops.
};
/// getHazardType - Return the hazard type of emitting this node. There are
/// three possible results. Either:
/// * NoHazard: it is legal to issue this instruction on this cycle.
/// * Hazard: issuing this instruction would stall the machine. If some
/// other instruction is available, issue it first.
/// * NoopHazard: issuing this instruction would break the program. If
/// some other instruction can be issued, do so, otherwise issue a noop.
virtual HazardType getHazardType(SDNode *) {
return NoHazard;
}
/// EmitInstruction - This callback is invoked when an instruction is
/// emitted, to advance the hazard state.
virtual void EmitInstruction(SDNode *) {}
/// AdvanceCycle - This callback is invoked when no instructions can be
/// issued on this cycle without a hazard. This should increment the
/// internal state of the hazard recognizer so that previously "Hazard"
/// instructions will now not be hazards.
virtual void AdvanceCycle() {}
/// EmitNoop - This callback is invoked when a noop was added to the
/// instruction stream.
virtual void EmitNoop() {}
};
/// ScheduleDAGSDNodes - A ScheduleDAG for scheduling SDNode-based DAGs.
///
/// Edges between SUnits are initially based on edges in the SelectionDAG,
/// and additional edges can be added by the schedulers as heuristics.
/// SDNodes such as Constants, Registers, and a few others that are not
/// interesting to schedulers are not allocated SUnits.
///
/// SDNodes with MVT::Flag operands are grouped along with the flagged
/// nodes into a single SUnit so that they are scheduled together.
///
/// SDNode-based scheduling graphs do not use SDep::Anti or SDep::Output
/// edges. Physical register dependence information is not carried in
/// the DAG and must be handled explicitly by schedulers.
///
class ScheduleDAGSDNodes : public ScheduleDAG {
public:
explicit ScheduleDAGSDNodes(MachineFunction &mf);
virtual ~ScheduleDAGSDNodes() {}
/// isPassiveNode - Return true if the node is a non-scheduled leaf.
///
static bool isPassiveNode(SDNode *Node) {
if (isa<ConstantSDNode>(Node)) return true;
if (isa<ConstantFPSDNode>(Node)) return true;
if (isa<RegisterSDNode>(Node)) return true;
if (isa<GlobalAddressSDNode>(Node)) return true;
if (isa<BasicBlockSDNode>(Node)) return true;
if (isa<FrameIndexSDNode>(Node)) return true;
if (isa<ConstantPoolSDNode>(Node)) return true;
if (isa<JumpTableSDNode>(Node)) return true;
if (isa<ExternalSymbolSDNode>(Node)) return true;
if (isa<MemOperandSDNode>(Node)) return true;
if (Node->getOpcode() == ISD::EntryToken) return true;
return false;
}
/// NewSUnit - Creates a new SUnit and return a ptr to it.
///
SUnit *NewSUnit(SDNode *N) {
#ifndef NDEBUG
const SUnit *Addr = 0;
if (SUnits.size() > 0)
Addr = &SUnits[0];
#endif
SUnits.push_back(SUnit(N, (unsigned)SUnits.size()));
assert((Addr == 0 || Addr == &SUnits[0]) &&
"SUnits std::vector reallocated on the fly!");
SUnits.back().OrigNode = &SUnits.back();
return &SUnits.back();
}
/// Clone - Creates a clone of the specified SUnit. It does not copy the
/// predecessors / successors info nor the temporary scheduling states.
///
SUnit *Clone(SUnit *N);
virtual SelectionDAG *getDAG() { return DAG; }
/// BuildSchedGraph - Build the SUnit graph from the selection dag that we
/// are input. This SUnit graph is similar to the SelectionDAG, but
/// excludes nodes that aren't interesting to scheduling, and represents
/// flagged together nodes with a single SUnit.
virtual void BuildSchedGraph();
/// ComputeLatency - Compute node latency.
///
virtual void ComputeLatency(SUnit *SU);
/// CountResults - The results of target nodes have register or immediate
/// operands first, then an optional chain, and optional flag operands
/// (which do not go into the machine instrs.)
static unsigned CountResults(SDNode *Node);
/// CountOperands - The inputs to target nodes have any actual inputs first,
/// followed by special operands that describe memory references, then an
/// optional chain operand, then flag operands. Compute the number of
/// actual operands that will go into the resulting MachineInstr.
static unsigned CountOperands(SDNode *Node);
/// ComputeMemOperandsEnd - Find the index one past the last
/// MemOperandSDNode operand
static unsigned ComputeMemOperandsEnd(SDNode *Node);
/// EmitNode - Generate machine code for an node and needed dependencies.
/// VRBaseMap contains, for each already emitted node, the first virtual
/// register number for the results of the node.
///
void EmitNode(SDNode *Node, bool IsClone,
DenseMap<SDValue, unsigned> &VRBaseMap);
virtual MachineBasicBlock *EmitSchedule();
/// Schedule - Order nodes according to selected style, filling
/// in the Sequence member.
///
virtual void Schedule() = 0;
virtual void dumpNode(const SUnit *SU) const;
virtual std::string getGraphNodeLabel(const SUnit *SU) const;
virtual void getCustomGraphFeatures(GraphWriter<ScheduleDAG*> &GW) const;
private:
/// EmitSubregNode - Generate machine code for subreg nodes.
///
void EmitSubregNode(SDNode *Node,
DenseMap<SDValue, unsigned> &VRBaseMap);
/// getVR - Return the virtual register corresponding to the specified result
/// of the specified node.
unsigned getVR(SDValue Op, DenseMap<SDValue, unsigned> &VRBaseMap);
/// getDstOfCopyToRegUse - If the only use of the specified result number of
/// node is a CopyToReg, return its destination register. Return 0 otherwise.
unsigned getDstOfOnlyCopyToRegUse(SDNode *Node, unsigned ResNo) const;
void AddOperand(MachineInstr *MI, SDValue Op, unsigned IIOpNum,
const TargetInstrDesc *II,
DenseMap<SDValue, unsigned> &VRBaseMap);
/// EmitCopyFromReg - Generate machine code for an CopyFromReg node or an
/// implicit physical register output.
void EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone,
unsigned SrcReg,
DenseMap<SDValue, unsigned> &VRBaseMap);
void CreateVirtualRegisters(SDNode *Node, MachineInstr *MI,
const TargetInstrDesc &II, bool IsClone,
DenseMap<SDValue, unsigned> &VRBaseMap);
/// BuildSchedUnits, AddSchedEdges - Helper functions for BuildSchedGraph.
void BuildSchedUnits();
void AddSchedEdges();
};
}
#endif
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