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8677f2ff9a
define below all header includes in the lib/CodeGen/... tree. While the current modules implementation doesn't check for this kind of ODR violation yet, it is likely to grow support for it in the future. It also removes one layer of macro pollution across all the included headers. Other sub-trees will follow. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206837 91177308-0d34-0410-b5e6-96231b3b80d8
644 lines
20 KiB
C++
644 lines
20 KiB
C++
//===---- ScheduleDAG.cpp - Implement the ScheduleDAG class ---------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This implements the ScheduleDAG class, which is a base class used by
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// scheduling implementation classes.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/ScheduleDAG.h"
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#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
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#include "llvm/CodeGen/SelectionDAGNodes.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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#include <climits>
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using namespace llvm;
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#define DEBUG_TYPE "pre-RA-sched"
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#ifndef NDEBUG
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static cl::opt<bool> StressSchedOpt(
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"stress-sched", cl::Hidden, cl::init(false),
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cl::desc("Stress test instruction scheduling"));
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#endif
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void SchedulingPriorityQueue::anchor() { }
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ScheduleDAG::ScheduleDAG(MachineFunction &mf)
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: TM(mf.getTarget()),
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TII(TM.getInstrInfo()),
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TRI(TM.getRegisterInfo()),
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MF(mf), MRI(mf.getRegInfo()),
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EntrySU(), ExitSU() {
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#ifndef NDEBUG
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StressSched = StressSchedOpt;
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#endif
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}
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ScheduleDAG::~ScheduleDAG() {}
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/// Clear the DAG state (e.g. between scheduling regions).
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void ScheduleDAG::clearDAG() {
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SUnits.clear();
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EntrySU = SUnit();
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ExitSU = SUnit();
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}
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/// getInstrDesc helper to handle SDNodes.
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const MCInstrDesc *ScheduleDAG::getNodeDesc(const SDNode *Node) const {
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if (!Node || !Node->isMachineOpcode()) return nullptr;
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return &TII->get(Node->getMachineOpcode());
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}
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/// addPred - This adds the specified edge as a pred of the current node if
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/// not already. It also adds the current node as a successor of the
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/// specified node.
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bool SUnit::addPred(const SDep &D, bool Required) {
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// If this node already has this dependence, don't add a redundant one.
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for (SmallVectorImpl<SDep>::iterator I = Preds.begin(), E = Preds.end();
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I != E; ++I) {
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// Zero-latency weak edges may be added purely for heuristic ordering. Don't
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// add them if another kind of edge already exists.
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if (!Required && I->getSUnit() == D.getSUnit())
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return false;
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if (I->overlaps(D)) {
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// Extend the latency if needed. Equivalent to removePred(I) + addPred(D).
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if (I->getLatency() < D.getLatency()) {
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SUnit *PredSU = I->getSUnit();
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// Find the corresponding successor in N.
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SDep ForwardD = *I;
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ForwardD.setSUnit(this);
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for (SmallVectorImpl<SDep>::iterator II = PredSU->Succs.begin(),
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EE = PredSU->Succs.end(); II != EE; ++II) {
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if (*II == ForwardD) {
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II->setLatency(D.getLatency());
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break;
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}
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}
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I->setLatency(D.getLatency());
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}
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return false;
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}
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}
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// Now add a corresponding succ to N.
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SDep P = D;
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P.setSUnit(this);
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SUnit *N = D.getSUnit();
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// Update the bookkeeping.
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if (D.getKind() == SDep::Data) {
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assert(NumPreds < UINT_MAX && "NumPreds will overflow!");
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assert(N->NumSuccs < UINT_MAX && "NumSuccs will overflow!");
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++NumPreds;
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++N->NumSuccs;
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}
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if (!N->isScheduled) {
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if (D.isWeak()) {
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++WeakPredsLeft;
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}
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else {
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assert(NumPredsLeft < UINT_MAX && "NumPredsLeft will overflow!");
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++NumPredsLeft;
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}
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}
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if (!isScheduled) {
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if (D.isWeak()) {
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++N->WeakSuccsLeft;
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}
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else {
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assert(N->NumSuccsLeft < UINT_MAX && "NumSuccsLeft will overflow!");
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++N->NumSuccsLeft;
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}
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}
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Preds.push_back(D);
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N->Succs.push_back(P);
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if (P.getLatency() != 0) {
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this->setDepthDirty();
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N->setHeightDirty();
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}
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return true;
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}
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/// removePred - This removes the specified edge as a pred of the current
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/// node if it exists. It also removes the current node as a successor of
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/// the specified node.
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void SUnit::removePred(const SDep &D) {
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// Find the matching predecessor.
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for (SmallVectorImpl<SDep>::iterator I = Preds.begin(), E = Preds.end();
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I != E; ++I)
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if (*I == D) {
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// Find the corresponding successor in N.
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SDep P = D;
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P.setSUnit(this);
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SUnit *N = D.getSUnit();
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SmallVectorImpl<SDep>::iterator Succ = std::find(N->Succs.begin(),
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N->Succs.end(), P);
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assert(Succ != N->Succs.end() && "Mismatching preds / succs lists!");
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N->Succs.erase(Succ);
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Preds.erase(I);
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// Update the bookkeeping.
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if (P.getKind() == SDep::Data) {
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assert(NumPreds > 0 && "NumPreds will underflow!");
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assert(N->NumSuccs > 0 && "NumSuccs will underflow!");
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--NumPreds;
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--N->NumSuccs;
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}
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if (!N->isScheduled) {
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if (D.isWeak())
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--WeakPredsLeft;
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else {
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assert(NumPredsLeft > 0 && "NumPredsLeft will underflow!");
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--NumPredsLeft;
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}
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}
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if (!isScheduled) {
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if (D.isWeak())
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--N->WeakSuccsLeft;
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else {
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assert(N->NumSuccsLeft > 0 && "NumSuccsLeft will underflow!");
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--N->NumSuccsLeft;
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}
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}
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if (P.getLatency() != 0) {
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this->setDepthDirty();
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N->setHeightDirty();
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}
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return;
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}
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}
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void SUnit::setDepthDirty() {
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if (!isDepthCurrent) return;
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SmallVector<SUnit*, 8> WorkList;
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WorkList.push_back(this);
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do {
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SUnit *SU = WorkList.pop_back_val();
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SU->isDepthCurrent = false;
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for (SUnit::const_succ_iterator I = SU->Succs.begin(),
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E = SU->Succs.end(); I != E; ++I) {
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SUnit *SuccSU = I->getSUnit();
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if (SuccSU->isDepthCurrent)
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WorkList.push_back(SuccSU);
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}
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} while (!WorkList.empty());
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}
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void SUnit::setHeightDirty() {
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if (!isHeightCurrent) return;
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SmallVector<SUnit*, 8> WorkList;
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WorkList.push_back(this);
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do {
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SUnit *SU = WorkList.pop_back_val();
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SU->isHeightCurrent = false;
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for (SUnit::const_pred_iterator I = SU->Preds.begin(),
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E = SU->Preds.end(); I != E; ++I) {
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SUnit *PredSU = I->getSUnit();
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if (PredSU->isHeightCurrent)
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WorkList.push_back(PredSU);
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}
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} while (!WorkList.empty());
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}
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/// setDepthToAtLeast - Update this node's successors to reflect the
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/// fact that this node's depth just increased.
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///
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void SUnit::setDepthToAtLeast(unsigned NewDepth) {
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if (NewDepth <= getDepth())
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return;
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setDepthDirty();
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Depth = NewDepth;
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isDepthCurrent = true;
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}
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/// setHeightToAtLeast - Update this node's predecessors to reflect the
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/// fact that this node's height just increased.
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///
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void SUnit::setHeightToAtLeast(unsigned NewHeight) {
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if (NewHeight <= getHeight())
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return;
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setHeightDirty();
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Height = NewHeight;
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isHeightCurrent = true;
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}
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/// ComputeDepth - Calculate the maximal path from the node to the exit.
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///
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void SUnit::ComputeDepth() {
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SmallVector<SUnit*, 8> WorkList;
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WorkList.push_back(this);
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do {
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SUnit *Cur = WorkList.back();
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bool Done = true;
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unsigned MaxPredDepth = 0;
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for (SUnit::const_pred_iterator I = Cur->Preds.begin(),
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E = Cur->Preds.end(); I != E; ++I) {
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SUnit *PredSU = I->getSUnit();
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if (PredSU->isDepthCurrent)
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MaxPredDepth = std::max(MaxPredDepth,
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PredSU->Depth + I->getLatency());
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else {
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Done = false;
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WorkList.push_back(PredSU);
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}
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}
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if (Done) {
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WorkList.pop_back();
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if (MaxPredDepth != Cur->Depth) {
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Cur->setDepthDirty();
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Cur->Depth = MaxPredDepth;
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}
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Cur->isDepthCurrent = true;
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}
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} while (!WorkList.empty());
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}
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/// ComputeHeight - Calculate the maximal path from the node to the entry.
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///
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void SUnit::ComputeHeight() {
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SmallVector<SUnit*, 8> WorkList;
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WorkList.push_back(this);
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do {
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SUnit *Cur = WorkList.back();
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bool Done = true;
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unsigned MaxSuccHeight = 0;
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for (SUnit::const_succ_iterator I = Cur->Succs.begin(),
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E = Cur->Succs.end(); I != E; ++I) {
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SUnit *SuccSU = I->getSUnit();
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if (SuccSU->isHeightCurrent)
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MaxSuccHeight = std::max(MaxSuccHeight,
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SuccSU->Height + I->getLatency());
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else {
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Done = false;
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WorkList.push_back(SuccSU);
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}
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}
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if (Done) {
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WorkList.pop_back();
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if (MaxSuccHeight != Cur->Height) {
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Cur->setHeightDirty();
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Cur->Height = MaxSuccHeight;
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}
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Cur->isHeightCurrent = true;
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}
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} while (!WorkList.empty());
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}
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void SUnit::biasCriticalPath() {
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if (NumPreds < 2)
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return;
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SUnit::pred_iterator BestI = Preds.begin();
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unsigned MaxDepth = BestI->getSUnit()->getDepth();
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for (SUnit::pred_iterator I = std::next(BestI), E = Preds.end(); I != E;
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++I) {
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if (I->getKind() == SDep::Data && I->getSUnit()->getDepth() > MaxDepth)
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BestI = I;
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}
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if (BestI != Preds.begin())
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std::swap(*Preds.begin(), *BestI);
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}
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#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
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/// SUnit - Scheduling unit. It's an wrapper around either a single SDNode or
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/// a group of nodes flagged together.
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void SUnit::dump(const ScheduleDAG *G) const {
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dbgs() << "SU(" << NodeNum << "): ";
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G->dumpNode(this);
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}
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void SUnit::dumpAll(const ScheduleDAG *G) const {
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dump(G);
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dbgs() << " # preds left : " << NumPredsLeft << "\n";
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dbgs() << " # succs left : " << NumSuccsLeft << "\n";
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if (WeakPredsLeft)
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dbgs() << " # weak preds left : " << WeakPredsLeft << "\n";
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if (WeakSuccsLeft)
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dbgs() << " # weak succs left : " << WeakSuccsLeft << "\n";
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dbgs() << " # rdefs left : " << NumRegDefsLeft << "\n";
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dbgs() << " Latency : " << Latency << "\n";
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dbgs() << " Depth : " << getDepth() << "\n";
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dbgs() << " Height : " << getHeight() << "\n";
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if (Preds.size() != 0) {
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dbgs() << " Predecessors:\n";
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for (SUnit::const_succ_iterator I = Preds.begin(), E = Preds.end();
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I != E; ++I) {
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dbgs() << " ";
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switch (I->getKind()) {
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case SDep::Data: dbgs() << "val "; break;
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case SDep::Anti: dbgs() << "anti"; break;
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case SDep::Output: dbgs() << "out "; break;
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case SDep::Order: dbgs() << "ch "; break;
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}
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dbgs() << "SU(" << I->getSUnit()->NodeNum << ")";
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if (I->isArtificial())
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dbgs() << " *";
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dbgs() << ": Latency=" << I->getLatency();
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if (I->isAssignedRegDep())
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dbgs() << " Reg=" << PrintReg(I->getReg(), G->TRI);
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dbgs() << "\n";
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}
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}
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if (Succs.size() != 0) {
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dbgs() << " Successors:\n";
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for (SUnit::const_succ_iterator I = Succs.begin(), E = Succs.end();
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I != E; ++I) {
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dbgs() << " ";
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switch (I->getKind()) {
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case SDep::Data: dbgs() << "val "; break;
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case SDep::Anti: dbgs() << "anti"; break;
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case SDep::Output: dbgs() << "out "; break;
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case SDep::Order: dbgs() << "ch "; break;
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}
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dbgs() << "SU(" << I->getSUnit()->NodeNum << ")";
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if (I->isArtificial())
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dbgs() << " *";
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dbgs() << ": Latency=" << I->getLatency();
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if (I->isAssignedRegDep())
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dbgs() << " Reg=" << PrintReg(I->getReg(), G->TRI);
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dbgs() << "\n";
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}
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}
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dbgs() << "\n";
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}
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#endif
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#ifndef NDEBUG
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/// VerifyScheduledDAG - Verify that all SUnits were scheduled and that
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/// their state is consistent. Return the number of scheduled nodes.
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///
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unsigned ScheduleDAG::VerifyScheduledDAG(bool isBottomUp) {
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bool AnyNotSched = false;
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unsigned DeadNodes = 0;
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for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
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if (!SUnits[i].isScheduled) {
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if (SUnits[i].NumPreds == 0 && SUnits[i].NumSuccs == 0) {
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++DeadNodes;
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continue;
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}
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if (!AnyNotSched)
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dbgs() << "*** Scheduling failed! ***\n";
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SUnits[i].dump(this);
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dbgs() << "has not been scheduled!\n";
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AnyNotSched = true;
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}
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if (SUnits[i].isScheduled &&
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(isBottomUp ? SUnits[i].getHeight() : SUnits[i].getDepth()) >
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unsigned(INT_MAX)) {
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if (!AnyNotSched)
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dbgs() << "*** Scheduling failed! ***\n";
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SUnits[i].dump(this);
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dbgs() << "has an unexpected "
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<< (isBottomUp ? "Height" : "Depth") << " value!\n";
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AnyNotSched = true;
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}
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if (isBottomUp) {
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if (SUnits[i].NumSuccsLeft != 0) {
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if (!AnyNotSched)
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dbgs() << "*** Scheduling failed! ***\n";
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SUnits[i].dump(this);
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dbgs() << "has successors left!\n";
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AnyNotSched = true;
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}
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} else {
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if (SUnits[i].NumPredsLeft != 0) {
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if (!AnyNotSched)
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dbgs() << "*** Scheduling failed! ***\n";
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SUnits[i].dump(this);
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dbgs() << "has predecessors left!\n";
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AnyNotSched = true;
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}
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}
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}
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assert(!AnyNotSched);
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return SUnits.size() - DeadNodes;
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}
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#endif
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/// InitDAGTopologicalSorting - create the initial topological
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/// ordering from the DAG to be scheduled.
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///
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/// The idea of the algorithm is taken from
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/// "Online algorithms for managing the topological order of
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/// a directed acyclic graph" by David J. Pearce and Paul H.J. Kelly
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/// This is the MNR algorithm, which was first introduced by
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/// A. Marchetti-Spaccamela, U. Nanni and H. Rohnert in
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/// "Maintaining a topological order under edge insertions".
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///
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/// Short description of the algorithm:
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///
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/// Topological ordering, ord, of a DAG maps each node to a topological
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/// index so that for all edges X->Y it is the case that ord(X) < ord(Y).
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///
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/// This means that if there is a path from the node X to the node Z,
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/// then ord(X) < ord(Z).
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///
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/// This property can be used to check for reachability of nodes:
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/// if Z is reachable from X, then an insertion of the edge Z->X would
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/// create a cycle.
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///
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/// The algorithm first computes a topological ordering for the DAG by
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/// initializing the Index2Node and Node2Index arrays and then tries to keep
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/// the ordering up-to-date after edge insertions by reordering the DAG.
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///
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/// On insertion of the edge X->Y, the algorithm first marks by calling DFS
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/// the nodes reachable from Y, and then shifts them using Shift to lie
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/// immediately after X in Index2Node.
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void ScheduleDAGTopologicalSort::InitDAGTopologicalSorting() {
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unsigned DAGSize = SUnits.size();
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std::vector<SUnit*> WorkList;
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WorkList.reserve(DAGSize);
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Index2Node.resize(DAGSize);
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Node2Index.resize(DAGSize);
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// Initialize the data structures.
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if (ExitSU)
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WorkList.push_back(ExitSU);
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for (unsigned i = 0, e = DAGSize; i != e; ++i) {
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SUnit *SU = &SUnits[i];
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int NodeNum = SU->NodeNum;
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unsigned Degree = SU->Succs.size();
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// Temporarily use the Node2Index array as scratch space for degree counts.
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Node2Index[NodeNum] = Degree;
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// Is it a node without dependencies?
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if (Degree == 0) {
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assert(SU->Succs.empty() && "SUnit should have no successors");
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// Collect leaf nodes.
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WorkList.push_back(SU);
|
|
}
|
|
}
|
|
|
|
int Id = DAGSize;
|
|
while (!WorkList.empty()) {
|
|
SUnit *SU = WorkList.back();
|
|
WorkList.pop_back();
|
|
if (SU->NodeNum < DAGSize)
|
|
Allocate(SU->NodeNum, --Id);
|
|
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
SUnit *SU = I->getSUnit();
|
|
if (SU->NodeNum < DAGSize && !--Node2Index[SU->NodeNum])
|
|
// If all dependencies of the node are processed already,
|
|
// then the node can be computed now.
|
|
WorkList.push_back(SU);
|
|
}
|
|
}
|
|
|
|
Visited.resize(DAGSize);
|
|
|
|
#ifndef NDEBUG
|
|
// Check correctness of the ordering
|
|
for (unsigned i = 0, e = DAGSize; i != e; ++i) {
|
|
SUnit *SU = &SUnits[i];
|
|
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
assert(Node2Index[SU->NodeNum] > Node2Index[I->getSUnit()->NodeNum] &&
|
|
"Wrong topological sorting");
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/// AddPred - Updates the topological ordering to accommodate an edge
|
|
/// to be added from SUnit X to SUnit Y.
|
|
void ScheduleDAGTopologicalSort::AddPred(SUnit *Y, SUnit *X) {
|
|
int UpperBound, LowerBound;
|
|
LowerBound = Node2Index[Y->NodeNum];
|
|
UpperBound = Node2Index[X->NodeNum];
|
|
bool HasLoop = false;
|
|
// Is Ord(X) < Ord(Y) ?
|
|
if (LowerBound < UpperBound) {
|
|
// Update the topological order.
|
|
Visited.reset();
|
|
DFS(Y, UpperBound, HasLoop);
|
|
assert(!HasLoop && "Inserted edge creates a loop!");
|
|
// Recompute topological indexes.
|
|
Shift(Visited, LowerBound, UpperBound);
|
|
}
|
|
}
|
|
|
|
/// RemovePred - Updates the topological ordering to accommodate an
|
|
/// an edge to be removed from the specified node N from the predecessors
|
|
/// of the current node M.
|
|
void ScheduleDAGTopologicalSort::RemovePred(SUnit *M, SUnit *N) {
|
|
// InitDAGTopologicalSorting();
|
|
}
|
|
|
|
/// DFS - Make a DFS traversal to mark all nodes reachable from SU and mark
|
|
/// all nodes affected by the edge insertion. These nodes will later get new
|
|
/// topological indexes by means of the Shift method.
|
|
void ScheduleDAGTopologicalSort::DFS(const SUnit *SU, int UpperBound,
|
|
bool &HasLoop) {
|
|
std::vector<const SUnit*> WorkList;
|
|
WorkList.reserve(SUnits.size());
|
|
|
|
WorkList.push_back(SU);
|
|
do {
|
|
SU = WorkList.back();
|
|
WorkList.pop_back();
|
|
Visited.set(SU->NodeNum);
|
|
for (int I = SU->Succs.size()-1; I >= 0; --I) {
|
|
unsigned s = SU->Succs[I].getSUnit()->NodeNum;
|
|
// Edges to non-SUnits are allowed but ignored (e.g. ExitSU).
|
|
if (s >= Node2Index.size())
|
|
continue;
|
|
if (Node2Index[s] == UpperBound) {
|
|
HasLoop = true;
|
|
return;
|
|
}
|
|
// Visit successors if not already and in affected region.
|
|
if (!Visited.test(s) && Node2Index[s] < UpperBound) {
|
|
WorkList.push_back(SU->Succs[I].getSUnit());
|
|
}
|
|
}
|
|
} while (!WorkList.empty());
|
|
}
|
|
|
|
/// Shift - Renumber the nodes so that the topological ordering is
|
|
/// preserved.
|
|
void ScheduleDAGTopologicalSort::Shift(BitVector& Visited, int LowerBound,
|
|
int UpperBound) {
|
|
std::vector<int> L;
|
|
int shift = 0;
|
|
int i;
|
|
|
|
for (i = LowerBound; i <= UpperBound; ++i) {
|
|
// w is node at topological index i.
|
|
int w = Index2Node[i];
|
|
if (Visited.test(w)) {
|
|
// Unmark.
|
|
Visited.reset(w);
|
|
L.push_back(w);
|
|
shift = shift + 1;
|
|
} else {
|
|
Allocate(w, i - shift);
|
|
}
|
|
}
|
|
|
|
for (unsigned j = 0; j < L.size(); ++j) {
|
|
Allocate(L[j], i - shift);
|
|
i = i + 1;
|
|
}
|
|
}
|
|
|
|
|
|
/// WillCreateCycle - Returns true if adding an edge to TargetSU from SU will
|
|
/// create a cycle. If so, it is not safe to call AddPred(TargetSU, SU).
|
|
bool ScheduleDAGTopologicalSort::WillCreateCycle(SUnit *TargetSU, SUnit *SU) {
|
|
// Is SU reachable from TargetSU via successor edges?
|
|
if (IsReachable(SU, TargetSU))
|
|
return true;
|
|
for (SUnit::pred_iterator
|
|
I = TargetSU->Preds.begin(), E = TargetSU->Preds.end(); I != E; ++I)
|
|
if (I->isAssignedRegDep() &&
|
|
IsReachable(SU, I->getSUnit()))
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/// IsReachable - Checks if SU is reachable from TargetSU.
|
|
bool ScheduleDAGTopologicalSort::IsReachable(const SUnit *SU,
|
|
const SUnit *TargetSU) {
|
|
// If insertion of the edge SU->TargetSU would create a cycle
|
|
// then there is a path from TargetSU to SU.
|
|
int UpperBound, LowerBound;
|
|
LowerBound = Node2Index[TargetSU->NodeNum];
|
|
UpperBound = Node2Index[SU->NodeNum];
|
|
bool HasLoop = false;
|
|
// Is Ord(TargetSU) < Ord(SU) ?
|
|
if (LowerBound < UpperBound) {
|
|
Visited.reset();
|
|
// There may be a path from TargetSU to SU. Check for it.
|
|
DFS(TargetSU, UpperBound, HasLoop);
|
|
}
|
|
return HasLoop;
|
|
}
|
|
|
|
/// Allocate - assign the topological index to the node n.
|
|
void ScheduleDAGTopologicalSort::Allocate(int n, int index) {
|
|
Node2Index[n] = index;
|
|
Index2Node[index] = n;
|
|
}
|
|
|
|
ScheduleDAGTopologicalSort::
|
|
ScheduleDAGTopologicalSort(std::vector<SUnit> &sunits, SUnit *exitsu)
|
|
: SUnits(sunits), ExitSU(exitsu) {}
|
|
|
|
ScheduleHazardRecognizer::~ScheduleHazardRecognizer() {}
|