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llvm-mirror/include/llvm/CodeGen/ScheduleDAG.h
2006-11-04 09:42:53 +00:00

307 lines
13 KiB
C++

//===------- llvm/CodeGen/ScheduleDAG.h - Common Base Class------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Evan Cheng and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the ScheduleDAG class, which is used as the common
// base class for SelectionDAG-based instruction scheduler.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_SCHEDULEDAG_H
#define LLVM_CODEGEN_SCHEDULEDAG_H
#include "llvm/CodeGen/SelectionDAG.h"
#include <set>
namespace llvm {
struct InstrStage;
class MachineConstantPool;
class MachineDebugInfo;
class MachineInstr;
class MRegisterInfo;
class SelectionDAG;
class SelectionDAGISel;
class SSARegMap;
class TargetInstrInfo;
class TargetInstrDescriptor;
class TargetMachine;
/// 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 *Node) {
return NoHazard;
}
/// EmitInstruction - This callback is invoked when an instruction is
/// emitted, to advance the hazard state.
virtual void EmitInstruction(SDNode *Node) {
}
/// 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() {
}
};
/// SUnit - Scheduling unit. It's an wrapper around either a single SDNode or
/// a group of nodes flagged together.
struct SUnit {
SDNode *Node; // Representative node.
SmallVector<SDNode*,4> FlaggedNodes;// All nodes flagged to Node.
// Preds/Succs - The SUnits before/after us in the graph. The boolean value
// is true if the edge is a token chain edge, false if it is a value edge.
SmallVector<std::pair<SUnit*,bool>, 4> Preds; // All sunit predecessors.
SmallVector<std::pair<SUnit*,bool>, 4> Succs; // All sunit successors.
typedef SmallVector<std::pair<SUnit*,bool>, 4>::iterator pred_iterator;
typedef SmallVector<std::pair<SUnit*,bool>, 4>::iterator succ_iterator;
typedef SmallVector<std::pair<SUnit*,bool>, 4>::const_iterator
const_pred_iterator;
typedef SmallVector<std::pair<SUnit*,bool>, 4>::const_iterator
const_succ_iterator;
short NumPreds; // # of preds.
short NumSuccs; // # of sucss.
short NumPredsLeft; // # of preds not scheduled.
short NumSuccsLeft; // # of succs not scheduled.
short NumChainPredsLeft; // # of chain preds not scheduled.
short NumChainSuccsLeft; // # of chain succs not scheduled.
bool isTwoAddress : 1; // Is a two-address instruction.
bool isCommutable : 1; // Is a commutable instruction.
bool isPending : 1; // True once pending.
bool isAvailable : 1; // True once available.
bool isScheduled : 1; // True once scheduled.
unsigned short Latency; // Node latency.
unsigned CycleBound; // Upper/lower cycle to be scheduled at.
unsigned Cycle; // Once scheduled, the cycle of the op.
unsigned Depth; // Node depth;
unsigned Height; // Node height;
unsigned NodeNum; // Entry # of node in the node vector.
SUnit(SDNode *node, unsigned nodenum)
: Node(node), NumPreds(0), NumSuccs(0), NumPredsLeft(0), NumSuccsLeft(0),
NumChainPredsLeft(0), NumChainSuccsLeft(0),
isTwoAddress(false), isCommutable(false),
isPending(false), isAvailable(false), isScheduled(false),
Latency(0), CycleBound(0), Cycle(0), Depth(0), Height(0),
NodeNum(nodenum) {}
/// addPred - This adds the specified node as a pred of the current node if
/// not already. This returns true if this is a new pred.
bool addPred(SUnit *N, bool isChain) {
for (unsigned i = 0, e = Preds.size(); i != e; ++i)
if (Preds[i].first == N && Preds[i].second == isChain)
return false;
Preds.push_back(std::make_pair(N, isChain));
return true;
}
/// addSucc - This adds the specified node as a succ of the current node if
/// not already. This returns true if this is a new succ.
bool addSucc(SUnit *N, bool isChain) {
for (unsigned i = 0, e = Succs.size(); i != e; ++i)
if (Succs[i].first == N && Succs[i].second == isChain)
return false;
Succs.push_back(std::make_pair(N, isChain));
return true;
}
void dump(const SelectionDAG *G) const;
void dumpAll(const SelectionDAG *G) const;
};
//===--------------------------------------------------------------------===//
/// SchedulingPriorityQueue - This interface is used to plug different
/// priorities computation algorithms into the list scheduler. It implements
/// the interface of a standard priority queue, where nodes are inserted in
/// arbitrary order and returned in priority order. The computation of the
/// priority and the representation of the queue are totally up to the
/// implementation to decide.
///
class SchedulingPriorityQueue {
public:
virtual ~SchedulingPriorityQueue() {}
virtual void initNodes(std::map<SDNode*, SUnit*> &SUMap,
std::vector<SUnit> &SUnits) = 0;
virtual void releaseState() = 0;
virtual bool empty() const = 0;
virtual void push(SUnit *U) = 0;
virtual void push_all(const std::vector<SUnit *> &Nodes) = 0;
virtual SUnit *pop() = 0;
/// ScheduledNode - As each node is scheduled, this method is invoked. This
/// allows the priority function to adjust the priority of node that have
/// already been emitted.
virtual void ScheduledNode(SUnit *Node) {}
};
class ScheduleDAG {
public:
SelectionDAG &DAG; // DAG of the current basic block
MachineBasicBlock *BB; // Current basic block
const TargetMachine &TM; // Target processor
const TargetInstrInfo *TII; // Target instruction information
const MRegisterInfo *MRI; // Target processor register info
SSARegMap *RegMap; // Virtual/real register map
MachineConstantPool *ConstPool; // Target constant pool
std::vector<SUnit*> Sequence; // The schedule. Null SUnit*'s
// represent noop instructions.
std::map<SDNode*, SUnit*> SUnitMap; // SDNode to SUnit mapping (n -> 1).
std::vector<SUnit> SUnits; // The scheduling units.
std::set<SDNode*> CommuteSet; // Nodes the should be commuted.
ScheduleDAG(SelectionDAG &dag, MachineBasicBlock *bb,
const TargetMachine &tm)
: DAG(dag), BB(bb), TM(tm) {}
virtual ~ScheduleDAG() {}
/// Run - perform scheduling.
///
MachineBasicBlock *Run();
/// isPassiveNode - Return true if the node is a non-scheduled leaf.
///
static bool isPassiveNode(SDNode *Node) {
if (isa<ConstantSDNode>(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;
return false;
}
/// NewSUnit - Creates a new SUnit and return a ptr to it.
///
SUnit *NewSUnit(SDNode *N) {
SUnits.push_back(SUnit(N, SUnits.size()));
return &SUnits.back();
}
/// BuildSchedUnits - Build SUnits from the selection dag that we are input.
/// This SUnit graph is similar to the SelectionDAG, but represents flagged
/// together nodes with a single SUnit.
void BuildSchedUnits();
/// CalculateDepths, CalculateHeights - Calculate node depth / height.
///
void CalculateDepths();
void CalculateHeights();
/// 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 an optional chain operand, then flag operands. Compute the
/// number of actual operands that will go into the machine instr.
static unsigned CountOperands(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, std::map<SDNode*, unsigned> &VRBaseMap);
/// EmitNoop - Emit a noop instruction.
///
void EmitNoop();
void EmitSchedule();
void dumpSchedule() const;
/// Schedule - Order nodes according to selected style.
///
virtual void Schedule() {}
private:
void AddOperand(MachineInstr *MI, SDOperand Op, unsigned IIOpNum,
const TargetInstrDescriptor *II,
std::map<SDNode*, unsigned> &VRBaseMap);
};
/// createBFS_DAGScheduler - This creates a simple breadth first instruction
/// scheduler.
ScheduleDAG *createBFS_DAGScheduler(SelectionDAGISel *IS,
SelectionDAG *DAG,
MachineBasicBlock *BB);
/// createSimpleDAGScheduler - This creates a simple two pass instruction
/// scheduler using instruction itinerary.
ScheduleDAG* createSimpleDAGScheduler(SelectionDAGISel *IS,
SelectionDAG *DAG,
MachineBasicBlock *BB);
/// createNoItinsDAGScheduler - This creates a simple two pass instruction
/// scheduler without using instruction itinerary.
ScheduleDAG* createNoItinsDAGScheduler(SelectionDAGISel *IS,
SelectionDAG *DAG,
MachineBasicBlock *BB);
/// createBURRListDAGScheduler - This creates a bottom up register usage
/// reduction list scheduler.
ScheduleDAG* createBURRListDAGScheduler(SelectionDAGISel *IS,
SelectionDAG *DAG,
MachineBasicBlock *BB);
/// createTDRRListDAGScheduler - This creates a top down register usage
/// reduction list scheduler.
ScheduleDAG* createTDRRListDAGScheduler(SelectionDAGISel *IS,
SelectionDAG *DAG,
MachineBasicBlock *BB);
/// createTDListDAGScheduler - This creates a top-down list scheduler with
/// a hazard recognizer.
ScheduleDAG* createTDListDAGScheduler(SelectionDAGISel *IS,
SelectionDAG *DAG,
MachineBasicBlock *BB);
/// createDefaultScheduler - This creates an instruction scheduler appropriate
/// for the target.
ScheduleDAG* createDefaultScheduler(SelectionDAGISel *IS,
SelectionDAG *DAG,
MachineBasicBlock *BB);
}
#endif