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Refactor the priority mechanism one step further: now that it is a separate

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class, sever its implementation from the interface.  Now we can provide new
implementations of the same interface (priority computation) without touching
the scheduler itself.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26630 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-03-09 06:35:14 +00:00
parent daac729f4d
commit e32178dd32
1 changed files with 185 additions and 136 deletions
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321
lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp
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@ -118,137 +118,25 @@ void SUnit::dump(const SelectionDAG *G, bool All) const {
}
}
namespace {
class SchedulingPriorityQueue;
//===----------------------------------------------------------------------===//
// 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() {}
/// Sorting functions for the Available queue.
struct ls_rr_sort : public std::binary_function<SUnit*, SUnit*, bool> {
SchedulingPriorityQueue *SPQ;
ls_rr_sort(SchedulingPriorityQueue *spq) : SPQ(spq) {}
ls_rr_sort(const ls_rr_sort &RHS) : SPQ(RHS.SPQ) {}
bool operator()(const SUnit* left, const SUnit* right) const;
};
} // end anonymous namespace
namespace {
class SchedulingPriorityQueue {
// SUnits - The SUnits for the current graph.
std::vector<SUnit> &SUnits;
// SethiUllmanNumbers - The SethiUllman number for each node.
std::vector<int> SethiUllmanNumbers;
std::priority_queue<SUnit*, std::vector<SUnit*>, ls_rr_sort> Queue;
public:
SchedulingPriorityQueue(std::vector<SUnit> &sunits)
: SUnits(sunits), Queue(ls_rr_sort(this)) {
// Calculate node priorities.
CalculatePriorities();
}
unsigned getSethiUllmanNumber(unsigned NodeNum) const {
assert(NodeNum < SethiUllmanNumbers.size());
return SethiUllmanNumbers[NodeNum];
}
bool empty() const { return Queue.empty(); }
void push(SUnit *U) {
Queue.push(U);
}
SUnit *pop() {
SUnit *V = Queue.top();
Queue.pop();
return V;
}
private:
void CalculatePriorities();
int CalcNodePriority(SUnit *SU);
};
}
bool ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const {
unsigned LeftNum = left->NodeNum;
unsigned RightNum = right->NodeNum;
virtual void initNodes(const std::vector<SUnit> &SUnits) = 0;
virtual void releaseState() = 0;
int LBonus = (int)left ->isDefNUseOperand;
int RBonus = (int)right->isDefNUseOperand;
// Special tie breaker: if two nodes share a operand, the one that
// use it as a def&use operand is preferred.
if (left->isTwoAddress && !right->isTwoAddress) {
SDNode *DUNode = left->Node->getOperand(0).Val;
if (DUNode->isOperand(right->Node))
LBonus++;
}
if (!left->isTwoAddress && right->isTwoAddress) {
SDNode *DUNode = right->Node->getOperand(0).Val;
if (DUNode->isOperand(left->Node))
RBonus++;
}
// Priority1 is just the number of live range genned.
int LPriority1 = left ->NumPredsLeft - LBonus;
int RPriority1 = right->NumPredsLeft - RBonus;
int LPriority2 = SPQ->getSethiUllmanNumber(LeftNum) + LBonus;
int RPriority2 = SPQ->getSethiUllmanNumber(RightNum) + RBonus;
if (LPriority1 > RPriority1)
return true;
else if (LPriority1 == RPriority1)
if (LPriority2 < RPriority2)
return true;
else if (LPriority2 == RPriority2)
if (left->CycleBound > right->CycleBound)
return true;
return false;
}
/// CalcNodePriority - Priority is the Sethi Ullman number.
/// Smaller number is the higher priority.
int SchedulingPriorityQueue::CalcNodePriority(SUnit *SU) {
int &SethiUllmanNumber = SethiUllmanNumbers[SU->NodeNum];
if (SethiUllmanNumber != INT_MIN)
return SethiUllmanNumber;
if (SU->Preds.size() == 0) {
SethiUllmanNumber = 1;
} else {
int Extra = 0;
for (std::set<SUnit*>::iterator I = SU->Preds.begin(),
E = SU->Preds.end(); I != E; ++I) {
SUnit *PredSU = *I;
int PredSethiUllman = CalcNodePriority(PredSU);
if (PredSethiUllman > SethiUllmanNumber) {
SethiUllmanNumber = PredSethiUllman;
Extra = 0;
} else if (PredSethiUllman == SethiUllmanNumber)
Extra++;
}
if (SU->Node->getOpcode() != ISD::TokenFactor)
SethiUllmanNumber += Extra;
else
SethiUllmanNumber = (Extra == 1) ? 0 : Extra-1;
}
return SethiUllmanNumber;
}
/// CalculatePriorities - Calculate priorities of all scheduling units.
void SchedulingPriorityQueue::CalculatePriorities() {
SethiUllmanNumbers.assign(SUnits.size(), INT_MIN);
for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
// FIXME: assumes uniform latency for now.
SUnits[i].Latency = 1;
(void)CalcNodePriority(&SUnits[i]);
}
}
virtual bool empty() const = 0;
virtual void push(SUnit *U) = 0;
virtual SUnit *pop() = 0;
};
@ -270,19 +158,25 @@ private:
/// it is top-down.
bool isBottomUp;
/// PriorityQueue - The priority queue to use.
SchedulingPriorityQueue *PriorityQueue;
/// HazardRec - The hazard recognizer to use.
HazardRecognizer *HazardRec;
public:
ScheduleDAGList(SelectionDAG &dag, MachineBasicBlock *bb,
const TargetMachine &tm, bool isbottomup,
SchedulingPriorityQueue *priorityqueue,
HazardRecognizer *HR)
: ScheduleDAG(listSchedulingBURR, dag, bb, tm),
CurrCycle(0), isBottomUp(isbottomup), HazardRec(HR) {
CurrCycle(0), isBottomUp(isbottomup),
PriorityQueue(priorityqueue), HazardRec(HR) {
}
~ScheduleDAGList() {
delete HazardRec;
delete PriorityQueue;
}
void Schedule();
@ -603,6 +497,9 @@ void ScheduleDAGList::BuildSchedUnits() {
SU = NewSUnit(N);
}
SUnitMap[N] = SU;
// FIXME: assumes uniform latency for now.
SU->Latency = 1;
}
// Pass 2: add the preds, succs, etc.
@ -701,14 +598,16 @@ void ScheduleDAGList::Schedule() {
// Build scheduling units.
BuildSchedUnits();
SchedulingPriorityQueue PQ(SUnits);
PriorityQueue->initNodes(SUnits);
// Execute the actual scheduling loop Top-Down or Bottom-Up as appropriate.
if (isBottomUp)
ListScheduleBottomUp(PQ);
ListScheduleBottomUp(*PriorityQueue);
else
ListScheduleTopDown(PQ);
ListScheduleTopDown(*PriorityQueue);
PriorityQueue->releaseState();
DEBUG(std::cerr << "*** Final schedule ***\n");
DEBUG(dump());
DEBUG(std::cerr << "\n");
@ -717,9 +616,157 @@ void ScheduleDAGList::Schedule() {
EmitSchedule();
}
//===----------------------------------------------------------------------===//
// RegReductionPriorityQueue Implementation
//===----------------------------------------------------------------------===//
//
// This is a SchedulingPriorityQueue that schedules using Sethi Ullman numbers
// to reduce register pressure.
//
namespace {
class RegReductionPriorityQueue;
/// Sorting functions for the Available queue.
struct ls_rr_sort : public std::binary_function<SUnit*, SUnit*, bool> {
RegReductionPriorityQueue *SPQ;
ls_rr_sort(RegReductionPriorityQueue *spq) : SPQ(spq) {}
ls_rr_sort(const ls_rr_sort &RHS) : SPQ(RHS.SPQ) {}
bool operator()(const SUnit* left, const SUnit* right) const;
};
} // end anonymous namespace
namespace {
class RegReductionPriorityQueue : public SchedulingPriorityQueue {
// SUnits - The SUnits for the current graph.
const std::vector<SUnit> *SUnits;
// SethiUllmanNumbers - The SethiUllman number for each node.
std::vector<int> SethiUllmanNumbers;
std::priority_queue<SUnit*, std::vector<SUnit*>, ls_rr_sort> Queue;
public:
RegReductionPriorityQueue() : Queue(ls_rr_sort(this)) {
}
void initNodes(const std::vector<SUnit> &sunits) {
SUnits = &sunits;
// Calculate node priorities.
CalculatePriorities();
}
void releaseState() {
SUnits = 0;
SethiUllmanNumbers.clear();
}
unsigned getSethiUllmanNumber(unsigned NodeNum) const {
assert(NodeNum < SethiUllmanNumbers.size());
return SethiUllmanNumbers[NodeNum];
}
bool empty() const { return Queue.empty(); }
void push(SUnit *U) {
Queue.push(U);
}
SUnit *pop() {
SUnit *V = Queue.top();
Queue.pop();
return V;
}
private:
void CalculatePriorities();
int CalcNodePriority(const SUnit *SU);
};
}
bool ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const {
unsigned LeftNum = left->NodeNum;
unsigned RightNum = right->NodeNum;
int LBonus = (int)left ->isDefNUseOperand;
int RBonus = (int)right->isDefNUseOperand;
// Special tie breaker: if two nodes share a operand, the one that
// use it as a def&use operand is preferred.
if (left->isTwoAddress && !right->isTwoAddress) {
SDNode *DUNode = left->Node->getOperand(0).Val;
if (DUNode->isOperand(right->Node))
LBonus++;
}
if (!left->isTwoAddress && right->isTwoAddress) {
SDNode *DUNode = right->Node->getOperand(0).Val;
if (DUNode->isOperand(left->Node))
RBonus++;
}
// Priority1 is just the number of live range genned.
int LPriority1 = left ->NumPredsLeft - LBonus;
int RPriority1 = right->NumPredsLeft - RBonus;
int LPriority2 = SPQ->getSethiUllmanNumber(LeftNum) + LBonus;
int RPriority2 = SPQ->getSethiUllmanNumber(RightNum) + RBonus;
if (LPriority1 > RPriority1)
return true;
else if (LPriority1 == RPriority1)
if (LPriority2 < RPriority2)
return true;
else if (LPriority2 == RPriority2)
if (left->CycleBound > right->CycleBound)
return true;
return false;
}
/// CalcNodePriority - Priority is the Sethi Ullman number.
/// Smaller number is the higher priority.
int RegReductionPriorityQueue::CalcNodePriority(const SUnit *SU) {
int &SethiUllmanNumber = SethiUllmanNumbers[SU->NodeNum];
if (SethiUllmanNumber != INT_MIN)
return SethiUllmanNumber;
if (SU->Preds.size() == 0) {
SethiUllmanNumber = 1;
} else {
int Extra = 0;
for (std::set<SUnit*>::iterator I = SU->Preds.begin(),
E = SU->Preds.end(); I != E; ++I) {
SUnit *PredSU = *I;
int PredSethiUllman = CalcNodePriority(PredSU);
if (PredSethiUllman > SethiUllmanNumber) {
SethiUllmanNumber = PredSethiUllman;
Extra = 0;
} else if (PredSethiUllman == SethiUllmanNumber)
Extra++;
}
if (SU->Node->getOpcode() != ISD::TokenFactor)
SethiUllmanNumber += Extra;
else
SethiUllmanNumber = (Extra == 1) ? 0 : Extra-1;
}
return SethiUllmanNumber;
}
/// CalculatePriorities - Calculate priorities of all scheduling units.
void RegReductionPriorityQueue::CalculatePriorities() {
SethiUllmanNumbers.assign(SUnits->size(), INT_MIN);
for (unsigned i = 0, e = SUnits->size(); i != e; ++i)
CalcNodePriority(&(*SUnits)[i]);
}
//===----------------------------------------------------------------------===//
// Public Constructor Functions
//===----------------------------------------------------------------------===//
llvm::ScheduleDAG* llvm::createBURRListDAGScheduler(SelectionDAG &DAG,
MachineBasicBlock *BB) {
return new ScheduleDAGList(DAG, BB, DAG.getTarget(), true,
new RegReductionPriorityQueue(),
new HazardRecognizer());
}
@ -728,5 +775,7 @@ llvm::ScheduleDAG* llvm::createBURRListDAGScheduler(SelectionDAG &DAG,
ScheduleDAG* llvm::createTDListDAGScheduler(SelectionDAG &DAG,
MachineBasicBlock *BB,
HazardRecognizer *HR) {
return new ScheduleDAGList(DAG, BB, DAG.getTarget(), false, HR);
return new ScheduleDAGList(DAG, BB, DAG.getTarget(), false,
new RegReductionPriorityQueue(),
HR);
}