1193323Sed//===---- ScheduleDAG.cpp - Implement the ScheduleDAG class ---------------===// 2193323Sed// 3193323Sed// The LLVM Compiler Infrastructure 4193323Sed// 5193323Sed// This file is distributed under the University of Illinois Open Source 6193323Sed// License. See LICENSE.TXT for details. 7193323Sed// 8193323Sed//===----------------------------------------------------------------------===// 9193323Sed// 10193323Sed// This implements the ScheduleDAG class, which is a base class used by 11193323Sed// scheduling implementation classes. 12193323Sed// 13193323Sed//===----------------------------------------------------------------------===// 14193323Sed 15193323Sed#define DEBUG_TYPE "pre-RA-sched" 16193323Sed#include "llvm/CodeGen/ScheduleDAG.h" 17193323Sed#include "llvm/CodeGen/ScheduleHazardRecognizer.h" 18218893Sdim#include "llvm/CodeGen/SelectionDAGNodes.h" 19224145Sdim#include "llvm/Support/CommandLine.h" 20193323Sed#include "llvm/Support/Debug.h" 21198090Srdivacky#include "llvm/Support/raw_ostream.h" 22249423Sdim#include "llvm/Target/TargetInstrInfo.h" 23249423Sdim#include "llvm/Target/TargetMachine.h" 24249423Sdim#include "llvm/Target/TargetRegisterInfo.h" 25193323Sed#include <climits> 26193323Sedusing namespace llvm; 27193323Sed 28224145Sdim#ifndef NDEBUG 29226633Sdimstatic cl::opt<bool> StressSchedOpt( 30224145Sdim "stress-sched", cl::Hidden, cl::init(false), 31224145Sdim cl::desc("Stress test instruction scheduling")); 32224145Sdim#endif 33224145Sdim 34234353Sdimvoid SchedulingPriorityQueue::anchor() { } 35234353Sdim 36193323SedScheduleDAG::ScheduleDAG(MachineFunction &mf) 37193323Sed : TM(mf.getTarget()), 38193323Sed TII(TM.getInstrInfo()), 39193323Sed TRI(TM.getRegisterInfo()), 40193323Sed MF(mf), MRI(mf.getRegInfo()), 41193323Sed EntrySU(), ExitSU() { 42224145Sdim#ifndef NDEBUG 43224145Sdim StressSched = StressSchedOpt; 44224145Sdim#endif 45193323Sed} 46193323Sed 47193323SedScheduleDAG::~ScheduleDAG() {} 48193323Sed 49234353Sdim/// Clear the DAG state (e.g. between scheduling regions). 50234353Sdimvoid ScheduleDAG::clearDAG() { 51234353Sdim SUnits.clear(); 52234353Sdim EntrySU = SUnit(); 53234353Sdim ExitSU = SUnit(); 54234353Sdim} 55234353Sdim 56218893Sdim/// getInstrDesc helper to handle SDNodes. 57224145Sdimconst MCInstrDesc *ScheduleDAG::getNodeDesc(const SDNode *Node) const { 58218893Sdim if (!Node || !Node->isMachineOpcode()) return NULL; 59218893Sdim return &TII->get(Node->getMachineOpcode()); 60218893Sdim} 61218893Sdim 62193323Sed/// addPred - This adds the specified edge as a pred of the current node if 63193323Sed/// not already. It also adds the current node as a successor of the 64193323Sed/// specified node. 65249423Sdimbool SUnit::addPred(const SDep &D, bool Required) { 66193323Sed // If this node already has this depenence, don't add a redundant one. 67263508Sdim for (SmallVectorImpl<SDep>::iterator I = Preds.begin(), E = Preds.end(); 68263508Sdim I != E; ++I) { 69249423Sdim // Zero-latency weak edges may be added purely for heuristic ordering. Don't 70249423Sdim // add them if another kind of edge already exists. 71249423Sdim if (!Required && I->getSUnit() == D.getSUnit()) 72249423Sdim return false; 73239462Sdim if (I->overlaps(D)) { 74239462Sdim // Extend the latency if needed. Equivalent to removePred(I) + addPred(D). 75239462Sdim if (I->getLatency() < D.getLatency()) { 76239462Sdim SUnit *PredSU = I->getSUnit(); 77239462Sdim // Find the corresponding successor in N. 78239462Sdim SDep ForwardD = *I; 79239462Sdim ForwardD.setSUnit(this); 80263508Sdim for (SmallVectorImpl<SDep>::iterator II = PredSU->Succs.begin(), 81239462Sdim EE = PredSU->Succs.end(); II != EE; ++II) { 82239462Sdim if (*II == ForwardD) { 83239462Sdim II->setLatency(D.getLatency()); 84239462Sdim break; 85239462Sdim } 86239462Sdim } 87239462Sdim I->setLatency(D.getLatency()); 88239462Sdim } 89218893Sdim return false; 90239462Sdim } 91239462Sdim } 92193323Sed // Now add a corresponding succ to N. 93193323Sed SDep P = D; 94193323Sed P.setSUnit(this); 95193323Sed SUnit *N = D.getSUnit(); 96193323Sed // Update the bookkeeping. 97193323Sed if (D.getKind() == SDep::Data) { 98198090Srdivacky assert(NumPreds < UINT_MAX && "NumPreds will overflow!"); 99198090Srdivacky assert(N->NumSuccs < UINT_MAX && "NumSuccs will overflow!"); 100193323Sed ++NumPreds; 101193323Sed ++N->NumSuccs; 102193323Sed } 103198090Srdivacky if (!N->isScheduled) { 104249423Sdim if (D.isWeak()) { 105249423Sdim ++WeakPredsLeft; 106249423Sdim } 107249423Sdim else { 108249423Sdim assert(NumPredsLeft < UINT_MAX && "NumPredsLeft will overflow!"); 109249423Sdim ++NumPredsLeft; 110249423Sdim } 111198090Srdivacky } 112198090Srdivacky if (!isScheduled) { 113249423Sdim if (D.isWeak()) { 114249423Sdim ++N->WeakSuccsLeft; 115249423Sdim } 116249423Sdim else { 117249423Sdim assert(N->NumSuccsLeft < UINT_MAX && "NumSuccsLeft will overflow!"); 118249423Sdim ++N->NumSuccsLeft; 119249423Sdim } 120198090Srdivacky } 121193323Sed Preds.push_back(D); 122193323Sed N->Succs.push_back(P); 123193323Sed if (P.getLatency() != 0) { 124193323Sed this->setDepthDirty(); 125193323Sed N->setHeightDirty(); 126193323Sed } 127218893Sdim return true; 128193323Sed} 129193323Sed 130193323Sed/// removePred - This removes the specified edge as a pred of the current 131193323Sed/// node if it exists. It also removes the current node as a successor of 132193323Sed/// the specified node. 133193323Sedvoid SUnit::removePred(const SDep &D) { 134193323Sed // Find the matching predecessor. 135263508Sdim for (SmallVectorImpl<SDep>::iterator I = Preds.begin(), E = Preds.end(); 136263508Sdim I != E; ++I) 137193323Sed if (*I == D) { 138193323Sed // Find the corresponding successor in N. 139193323Sed SDep P = D; 140193323Sed P.setSUnit(this); 141193323Sed SUnit *N = D.getSUnit(); 142249423Sdim SmallVectorImpl<SDep>::iterator Succ = std::find(N->Succs.begin(), 143249423Sdim N->Succs.end(), P); 144249423Sdim assert(Succ != N->Succs.end() && "Mismatching preds / succs lists!"); 145249423Sdim N->Succs.erase(Succ); 146193323Sed Preds.erase(I); 147193323Sed // Update the bookkeeping. 148193323Sed if (P.getKind() == SDep::Data) { 149198090Srdivacky assert(NumPreds > 0 && "NumPreds will underflow!"); 150198090Srdivacky assert(N->NumSuccs > 0 && "NumSuccs will underflow!"); 151193323Sed --NumPreds; 152193323Sed --N->NumSuccs; 153193323Sed } 154198090Srdivacky if (!N->isScheduled) { 155249423Sdim if (D.isWeak()) 156249423Sdim --WeakPredsLeft; 157249423Sdim else { 158249423Sdim assert(NumPredsLeft > 0 && "NumPredsLeft will underflow!"); 159249423Sdim --NumPredsLeft; 160249423Sdim } 161198090Srdivacky } 162198090Srdivacky if (!isScheduled) { 163249423Sdim if (D.isWeak()) 164249423Sdim --N->WeakSuccsLeft; 165249423Sdim else { 166249423Sdim assert(N->NumSuccsLeft > 0 && "NumSuccsLeft will underflow!"); 167249423Sdim --N->NumSuccsLeft; 168249423Sdim } 169198090Srdivacky } 170193323Sed if (P.getLatency() != 0) { 171193323Sed this->setDepthDirty(); 172193323Sed N->setHeightDirty(); 173193323Sed } 174193323Sed return; 175193323Sed } 176193323Sed} 177193323Sed 178193323Sedvoid SUnit::setDepthDirty() { 179193323Sed if (!isDepthCurrent) return; 180193323Sed SmallVector<SUnit*, 8> WorkList; 181193323Sed WorkList.push_back(this); 182193323Sed do { 183193323Sed SUnit *SU = WorkList.pop_back_val(); 184193323Sed SU->isDepthCurrent = false; 185193323Sed for (SUnit::const_succ_iterator I = SU->Succs.begin(), 186193323Sed E = SU->Succs.end(); I != E; ++I) { 187193323Sed SUnit *SuccSU = I->getSUnit(); 188193323Sed if (SuccSU->isDepthCurrent) 189193323Sed WorkList.push_back(SuccSU); 190193323Sed } 191193323Sed } while (!WorkList.empty()); 192193323Sed} 193193323Sed 194193323Sedvoid SUnit::setHeightDirty() { 195193323Sed if (!isHeightCurrent) return; 196193323Sed SmallVector<SUnit*, 8> WorkList; 197193323Sed WorkList.push_back(this); 198193323Sed do { 199193323Sed SUnit *SU = WorkList.pop_back_val(); 200193323Sed SU->isHeightCurrent = false; 201193323Sed for (SUnit::const_pred_iterator I = SU->Preds.begin(), 202193323Sed E = SU->Preds.end(); I != E; ++I) { 203193323Sed SUnit *PredSU = I->getSUnit(); 204193323Sed if (PredSU->isHeightCurrent) 205193323Sed WorkList.push_back(PredSU); 206193323Sed } 207193323Sed } while (!WorkList.empty()); 208193323Sed} 209193323Sed 210193323Sed/// setDepthToAtLeast - Update this node's successors to reflect the 211193323Sed/// fact that this node's depth just increased. 212193323Sed/// 213199989Srdivackyvoid SUnit::setDepthToAtLeast(unsigned NewDepth) { 214199989Srdivacky if (NewDepth <= getDepth()) 215193323Sed return; 216193323Sed setDepthDirty(); 217193323Sed Depth = NewDepth; 218193323Sed isDepthCurrent = true; 219193323Sed} 220193323Sed 221193323Sed/// setHeightToAtLeast - Update this node's predecessors to reflect the 222193323Sed/// fact that this node's height just increased. 223193323Sed/// 224199989Srdivackyvoid SUnit::setHeightToAtLeast(unsigned NewHeight) { 225199989Srdivacky if (NewHeight <= getHeight()) 226193323Sed return; 227193323Sed setHeightDirty(); 228193323Sed Height = NewHeight; 229193323Sed isHeightCurrent = true; 230193323Sed} 231193323Sed 232193323Sed/// ComputeDepth - Calculate the maximal path from the node to the exit. 233193323Sed/// 234199989Srdivackyvoid SUnit::ComputeDepth() { 235193323Sed SmallVector<SUnit*, 8> WorkList; 236193323Sed WorkList.push_back(this); 237193323Sed do { 238193323Sed SUnit *Cur = WorkList.back(); 239193323Sed 240193323Sed bool Done = true; 241193323Sed unsigned MaxPredDepth = 0; 242193323Sed for (SUnit::const_pred_iterator I = Cur->Preds.begin(), 243193323Sed E = Cur->Preds.end(); I != E; ++I) { 244193323Sed SUnit *PredSU = I->getSUnit(); 245193323Sed if (PredSU->isDepthCurrent) 246193323Sed MaxPredDepth = std::max(MaxPredDepth, 247193323Sed PredSU->Depth + I->getLatency()); 248193323Sed else { 249193323Sed Done = false; 250193323Sed WorkList.push_back(PredSU); 251193323Sed } 252193323Sed } 253193323Sed 254193323Sed if (Done) { 255193323Sed WorkList.pop_back(); 256193323Sed if (MaxPredDepth != Cur->Depth) { 257193323Sed Cur->setDepthDirty(); 258193323Sed Cur->Depth = MaxPredDepth; 259193323Sed } 260193323Sed Cur->isDepthCurrent = true; 261193323Sed } 262193323Sed } while (!WorkList.empty()); 263193323Sed} 264193323Sed 265193323Sed/// ComputeHeight - Calculate the maximal path from the node to the entry. 266193323Sed/// 267199989Srdivackyvoid SUnit::ComputeHeight() { 268193323Sed SmallVector<SUnit*, 8> WorkList; 269193323Sed WorkList.push_back(this); 270193323Sed do { 271193323Sed SUnit *Cur = WorkList.back(); 272193323Sed 273193323Sed bool Done = true; 274193323Sed unsigned MaxSuccHeight = 0; 275193323Sed for (SUnit::const_succ_iterator I = Cur->Succs.begin(), 276193323Sed E = Cur->Succs.end(); I != E; ++I) { 277193323Sed SUnit *SuccSU = I->getSUnit(); 278193323Sed if (SuccSU->isHeightCurrent) 279193323Sed MaxSuccHeight = std::max(MaxSuccHeight, 280193323Sed SuccSU->Height + I->getLatency()); 281193323Sed else { 282193323Sed Done = false; 283193323Sed WorkList.push_back(SuccSU); 284193323Sed } 285193323Sed } 286193323Sed 287193323Sed if (Done) { 288193323Sed WorkList.pop_back(); 289193323Sed if (MaxSuccHeight != Cur->Height) { 290193323Sed Cur->setHeightDirty(); 291193323Sed Cur->Height = MaxSuccHeight; 292193323Sed } 293193323Sed Cur->isHeightCurrent = true; 294193323Sed } 295193323Sed } while (!WorkList.empty()); 296193323Sed} 297193323Sed 298249423Sdimvoid SUnit::biasCriticalPath() { 299249423Sdim if (NumPreds < 2) 300249423Sdim return; 301249423Sdim 302249423Sdim SUnit::pred_iterator BestI = Preds.begin(); 303249423Sdim unsigned MaxDepth = BestI->getSUnit()->getDepth(); 304249423Sdim for (SUnit::pred_iterator 305249423Sdim I = llvm::next(BestI), E = Preds.end(); I != E; ++I) { 306249423Sdim if (I->getKind() == SDep::Data && I->getSUnit()->getDepth() > MaxDepth) 307249423Sdim BestI = I; 308249423Sdim } 309249423Sdim if (BestI != Preds.begin()) 310249423Sdim std::swap(*Preds.begin(), *BestI); 311249423Sdim} 312249423Sdim 313243830Sdim#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 314193323Sed/// SUnit - Scheduling unit. It's an wrapper around either a single SDNode or 315193323Sed/// a group of nodes flagged together. 316193323Sedvoid SUnit::dump(const ScheduleDAG *G) const { 317202375Srdivacky dbgs() << "SU(" << NodeNum << "): "; 318193323Sed G->dumpNode(this); 319193323Sed} 320193323Sed 321193323Sedvoid SUnit::dumpAll(const ScheduleDAG *G) const { 322193323Sed dump(G); 323193323Sed 324202375Srdivacky dbgs() << " # preds left : " << NumPredsLeft << "\n"; 325202375Srdivacky dbgs() << " # succs left : " << NumSuccsLeft << "\n"; 326249423Sdim if (WeakPredsLeft) 327249423Sdim dbgs() << " # weak preds left : " << WeakPredsLeft << "\n"; 328249423Sdim if (WeakSuccsLeft) 329249423Sdim dbgs() << " # weak succs left : " << WeakSuccsLeft << "\n"; 330218893Sdim dbgs() << " # rdefs left : " << NumRegDefsLeft << "\n"; 331202375Srdivacky dbgs() << " Latency : " << Latency << "\n"; 332249423Sdim dbgs() << " Depth : " << getDepth() << "\n"; 333249423Sdim dbgs() << " Height : " << getHeight() << "\n"; 334193323Sed 335193323Sed if (Preds.size() != 0) { 336202375Srdivacky dbgs() << " Predecessors:\n"; 337193323Sed for (SUnit::const_succ_iterator I = Preds.begin(), E = Preds.end(); 338193323Sed I != E; ++I) { 339202375Srdivacky dbgs() << " "; 340193323Sed switch (I->getKind()) { 341202375Srdivacky case SDep::Data: dbgs() << "val "; break; 342202375Srdivacky case SDep::Anti: dbgs() << "anti"; break; 343202375Srdivacky case SDep::Output: dbgs() << "out "; break; 344202375Srdivacky case SDep::Order: dbgs() << "ch "; break; 345193323Sed } 346234353Sdim dbgs() << "SU(" << I->getSUnit()->NodeNum << ")"; 347193323Sed if (I->isArtificial()) 348202375Srdivacky dbgs() << " *"; 349202375Srdivacky dbgs() << ": Latency=" << I->getLatency(); 350224145Sdim if (I->isAssignedRegDep()) 351234353Sdim dbgs() << " Reg=" << PrintReg(I->getReg(), G->TRI); 352202375Srdivacky dbgs() << "\n"; 353193323Sed } 354193323Sed } 355193323Sed if (Succs.size() != 0) { 356202375Srdivacky dbgs() << " Successors:\n"; 357193323Sed for (SUnit::const_succ_iterator I = Succs.begin(), E = Succs.end(); 358193323Sed I != E; ++I) { 359202375Srdivacky dbgs() << " "; 360193323Sed switch (I->getKind()) { 361202375Srdivacky case SDep::Data: dbgs() << "val "; break; 362202375Srdivacky case SDep::Anti: dbgs() << "anti"; break; 363202375Srdivacky case SDep::Output: dbgs() << "out "; break; 364202375Srdivacky case SDep::Order: dbgs() << "ch "; break; 365193323Sed } 366234353Sdim dbgs() << "SU(" << I->getSUnit()->NodeNum << ")"; 367193323Sed if (I->isArtificial()) 368202375Srdivacky dbgs() << " *"; 369202375Srdivacky dbgs() << ": Latency=" << I->getLatency(); 370249423Sdim if (I->isAssignedRegDep()) 371249423Sdim dbgs() << " Reg=" << PrintReg(I->getReg(), G->TRI); 372202375Srdivacky dbgs() << "\n"; 373193323Sed } 374193323Sed } 375202375Srdivacky dbgs() << "\n"; 376193323Sed} 377243830Sdim#endif 378193323Sed 379193323Sed#ifndef NDEBUG 380234353Sdim/// VerifyScheduledDAG - Verify that all SUnits were scheduled and that 381234353Sdim/// their state is consistent. Return the number of scheduled nodes. 382193323Sed/// 383234353Sdimunsigned ScheduleDAG::VerifyScheduledDAG(bool isBottomUp) { 384193323Sed bool AnyNotSched = false; 385193323Sed unsigned DeadNodes = 0; 386193323Sed for (unsigned i = 0, e = SUnits.size(); i != e; ++i) { 387193323Sed if (!SUnits[i].isScheduled) { 388193323Sed if (SUnits[i].NumPreds == 0 && SUnits[i].NumSuccs == 0) { 389193323Sed ++DeadNodes; 390193323Sed continue; 391193323Sed } 392193323Sed if (!AnyNotSched) 393202375Srdivacky dbgs() << "*** Scheduling failed! ***\n"; 394193323Sed SUnits[i].dump(this); 395202375Srdivacky dbgs() << "has not been scheduled!\n"; 396193323Sed AnyNotSched = true; 397193323Sed } 398193323Sed if (SUnits[i].isScheduled && 399198892Srdivacky (isBottomUp ? SUnits[i].getHeight() : SUnits[i].getDepth()) > 400193323Sed unsigned(INT_MAX)) { 401193323Sed if (!AnyNotSched) 402202375Srdivacky dbgs() << "*** Scheduling failed! ***\n"; 403193323Sed SUnits[i].dump(this); 404202375Srdivacky dbgs() << "has an unexpected " 405193323Sed << (isBottomUp ? "Height" : "Depth") << " value!\n"; 406193323Sed AnyNotSched = true; 407193323Sed } 408193323Sed if (isBottomUp) { 409193323Sed if (SUnits[i].NumSuccsLeft != 0) { 410193323Sed if (!AnyNotSched) 411202375Srdivacky dbgs() << "*** Scheduling failed! ***\n"; 412193323Sed SUnits[i].dump(this); 413202375Srdivacky dbgs() << "has successors left!\n"; 414193323Sed AnyNotSched = true; 415193323Sed } 416193323Sed } else { 417193323Sed if (SUnits[i].NumPredsLeft != 0) { 418193323Sed if (!AnyNotSched) 419202375Srdivacky dbgs() << "*** Scheduling failed! ***\n"; 420193323Sed SUnits[i].dump(this); 421202375Srdivacky dbgs() << "has predecessors left!\n"; 422193323Sed AnyNotSched = true; 423193323Sed } 424193323Sed } 425193323Sed } 426193323Sed assert(!AnyNotSched); 427234353Sdim return SUnits.size() - DeadNodes; 428193323Sed} 429193323Sed#endif 430193323Sed 431210299Sed/// InitDAGTopologicalSorting - create the initial topological 432193323Sed/// ordering from the DAG to be scheduled. 433193323Sed/// 434210299Sed/// The idea of the algorithm is taken from 435193323Sed/// "Online algorithms for managing the topological order of 436193323Sed/// a directed acyclic graph" by David J. Pearce and Paul H.J. Kelly 437210299Sed/// This is the MNR algorithm, which was first introduced by 438210299Sed/// A. Marchetti-Spaccamela, U. Nanni and H. Rohnert in 439193323Sed/// "Maintaining a topological order under edge insertions". 440193323Sed/// 441210299Sed/// Short description of the algorithm: 442193323Sed/// 443193323Sed/// Topological ordering, ord, of a DAG maps each node to a topological 444193323Sed/// index so that for all edges X->Y it is the case that ord(X) < ord(Y). 445193323Sed/// 446210299Sed/// This means that if there is a path from the node X to the node Z, 447193323Sed/// then ord(X) < ord(Z). 448193323Sed/// 449193323Sed/// This property can be used to check for reachability of nodes: 450210299Sed/// if Z is reachable from X, then an insertion of the edge Z->X would 451193323Sed/// create a cycle. 452193323Sed/// 453193323Sed/// The algorithm first computes a topological ordering for the DAG by 454193323Sed/// initializing the Index2Node and Node2Index arrays and then tries to keep 455193323Sed/// the ordering up-to-date after edge insertions by reordering the DAG. 456193323Sed/// 457193323Sed/// On insertion of the edge X->Y, the algorithm first marks by calling DFS 458193323Sed/// the nodes reachable from Y, and then shifts them using Shift to lie 459193323Sed/// immediately after X in Index2Node. 460193323Sedvoid ScheduleDAGTopologicalSort::InitDAGTopologicalSorting() { 461193323Sed unsigned DAGSize = SUnits.size(); 462193323Sed std::vector<SUnit*> WorkList; 463193323Sed WorkList.reserve(DAGSize); 464193323Sed 465193323Sed Index2Node.resize(DAGSize); 466193323Sed Node2Index.resize(DAGSize); 467193323Sed 468193323Sed // Initialize the data structures. 469249423Sdim if (ExitSU) 470249423Sdim WorkList.push_back(ExitSU); 471193323Sed for (unsigned i = 0, e = DAGSize; i != e; ++i) { 472193323Sed SUnit *SU = &SUnits[i]; 473193323Sed int NodeNum = SU->NodeNum; 474193323Sed unsigned Degree = SU->Succs.size(); 475193323Sed // Temporarily use the Node2Index array as scratch space for degree counts. 476193323Sed Node2Index[NodeNum] = Degree; 477193323Sed 478193323Sed // Is it a node without dependencies? 479193323Sed if (Degree == 0) { 480193323Sed assert(SU->Succs.empty() && "SUnit should have no successors"); 481193323Sed // Collect leaf nodes. 482193323Sed WorkList.push_back(SU); 483193323Sed } 484210299Sed } 485193323Sed 486193323Sed int Id = DAGSize; 487193323Sed while (!WorkList.empty()) { 488193323Sed SUnit *SU = WorkList.back(); 489193323Sed WorkList.pop_back(); 490249423Sdim if (SU->NodeNum < DAGSize) 491249423Sdim Allocate(SU->NodeNum, --Id); 492193323Sed for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end(); 493193323Sed I != E; ++I) { 494193323Sed SUnit *SU = I->getSUnit(); 495249423Sdim if (SU->NodeNum < DAGSize && !--Node2Index[SU->NodeNum]) 496193323Sed // If all dependencies of the node are processed already, 497193323Sed // then the node can be computed now. 498193323Sed WorkList.push_back(SU); 499193323Sed } 500193323Sed } 501193323Sed 502193323Sed Visited.resize(DAGSize); 503193323Sed 504193323Sed#ifndef NDEBUG 505193323Sed // Check correctness of the ordering 506193323Sed for (unsigned i = 0, e = DAGSize; i != e; ++i) { 507193323Sed SUnit *SU = &SUnits[i]; 508193323Sed for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end(); 509193323Sed I != E; ++I) { 510210299Sed assert(Node2Index[SU->NodeNum] > Node2Index[I->getSUnit()->NodeNum] && 511193323Sed "Wrong topological sorting"); 512193323Sed } 513193323Sed } 514193323Sed#endif 515193323Sed} 516193323Sed 517221345Sdim/// AddPred - Updates the topological ordering to accommodate an edge 518193323Sed/// to be added from SUnit X to SUnit Y. 519193323Sedvoid ScheduleDAGTopologicalSort::AddPred(SUnit *Y, SUnit *X) { 520193323Sed int UpperBound, LowerBound; 521193323Sed LowerBound = Node2Index[Y->NodeNum]; 522193323Sed UpperBound = Node2Index[X->NodeNum]; 523193323Sed bool HasLoop = false; 524193323Sed // Is Ord(X) < Ord(Y) ? 525193323Sed if (LowerBound < UpperBound) { 526193323Sed // Update the topological order. 527193323Sed Visited.reset(); 528193323Sed DFS(Y, UpperBound, HasLoop); 529193323Sed assert(!HasLoop && "Inserted edge creates a loop!"); 530193323Sed // Recompute topological indexes. 531193323Sed Shift(Visited, LowerBound, UpperBound); 532193323Sed } 533193323Sed} 534193323Sed 535221345Sdim/// RemovePred - Updates the topological ordering to accommodate an 536193323Sed/// an edge to be removed from the specified node N from the predecessors 537193323Sed/// of the current node M. 538193323Sedvoid ScheduleDAGTopologicalSort::RemovePred(SUnit *M, SUnit *N) { 539193323Sed // InitDAGTopologicalSorting(); 540193323Sed} 541193323Sed 542193323Sed/// DFS - Make a DFS traversal to mark all nodes reachable from SU and mark 543193323Sed/// all nodes affected by the edge insertion. These nodes will later get new 544193323Sed/// topological indexes by means of the Shift method. 545193323Sedvoid ScheduleDAGTopologicalSort::DFS(const SUnit *SU, int UpperBound, 546218893Sdim bool &HasLoop) { 547193323Sed std::vector<const SUnit*> WorkList; 548210299Sed WorkList.reserve(SUnits.size()); 549193323Sed 550193323Sed WorkList.push_back(SU); 551193323Sed do { 552193323Sed SU = WorkList.back(); 553193323Sed WorkList.pop_back(); 554193323Sed Visited.set(SU->NodeNum); 555193323Sed for (int I = SU->Succs.size()-1; I >= 0; --I) { 556249423Sdim unsigned s = SU->Succs[I].getSUnit()->NodeNum; 557249423Sdim // Edges to non-SUnits are allowed but ignored (e.g. ExitSU). 558249423Sdim if (s >= Node2Index.size()) 559249423Sdim continue; 560193323Sed if (Node2Index[s] == UpperBound) { 561210299Sed HasLoop = true; 562193323Sed return; 563193323Sed } 564193323Sed // Visit successors if not already and in affected region. 565193323Sed if (!Visited.test(s) && Node2Index[s] < UpperBound) { 566193323Sed WorkList.push_back(SU->Succs[I].getSUnit()); 567210299Sed } 568210299Sed } 569193323Sed } while (!WorkList.empty()); 570193323Sed} 571193323Sed 572210299Sed/// Shift - Renumber the nodes so that the topological ordering is 573193323Sed/// preserved. 574210299Sedvoid ScheduleDAGTopologicalSort::Shift(BitVector& Visited, int LowerBound, 575193323Sed int UpperBound) { 576193323Sed std::vector<int> L; 577193323Sed int shift = 0; 578193323Sed int i; 579193323Sed 580193323Sed for (i = LowerBound; i <= UpperBound; ++i) { 581193323Sed // w is node at topological index i. 582193323Sed int w = Index2Node[i]; 583193323Sed if (Visited.test(w)) { 584193323Sed // Unmark. 585193323Sed Visited.reset(w); 586193323Sed L.push_back(w); 587193323Sed shift = shift + 1; 588193323Sed } else { 589193323Sed Allocate(w, i - shift); 590193323Sed } 591193323Sed } 592193323Sed 593193323Sed for (unsigned j = 0; j < L.size(); ++j) { 594193323Sed Allocate(L[j], i - shift); 595193323Sed i = i + 1; 596193323Sed } 597193323Sed} 598193323Sed 599193323Sed 600249423Sdim/// WillCreateCycle - Returns true if adding an edge to TargetSU from SU will 601249423Sdim/// create a cycle. If so, it is not safe to call AddPred(TargetSU, SU). 602249423Sdimbool ScheduleDAGTopologicalSort::WillCreateCycle(SUnit *TargetSU, SUnit *SU) { 603249423Sdim // Is SU reachable from TargetSU via successor edges? 604249423Sdim if (IsReachable(SU, TargetSU)) 605193323Sed return true; 606249423Sdim for (SUnit::pred_iterator 607249423Sdim I = TargetSU->Preds.begin(), E = TargetSU->Preds.end(); I != E; ++I) 608193323Sed if (I->isAssignedRegDep() && 609249423Sdim IsReachable(SU, I->getSUnit())) 610193323Sed return true; 611193323Sed return false; 612193323Sed} 613193323Sed 614193323Sed/// IsReachable - Checks if SU is reachable from TargetSU. 615193323Sedbool ScheduleDAGTopologicalSort::IsReachable(const SUnit *SU, 616193323Sed const SUnit *TargetSU) { 617193323Sed // If insertion of the edge SU->TargetSU would create a cycle 618193323Sed // then there is a path from TargetSU to SU. 619193323Sed int UpperBound, LowerBound; 620193323Sed LowerBound = Node2Index[TargetSU->NodeNum]; 621193323Sed UpperBound = Node2Index[SU->NodeNum]; 622193323Sed bool HasLoop = false; 623193323Sed // Is Ord(TargetSU) < Ord(SU) ? 624193323Sed if (LowerBound < UpperBound) { 625193323Sed Visited.reset(); 626210299Sed // There may be a path from TargetSU to SU. Check for it. 627193323Sed DFS(TargetSU, UpperBound, HasLoop); 628193323Sed } 629193323Sed return HasLoop; 630193323Sed} 631193323Sed 632193323Sed/// Allocate - assign the topological index to the node n. 633193323Sedvoid ScheduleDAGTopologicalSort::Allocate(int n, int index) { 634193323Sed Node2Index[n] = index; 635193323Sed Index2Node[index] = n; 636193323Sed} 637193323Sed 638210299SedScheduleDAGTopologicalSort:: 639249423SdimScheduleDAGTopologicalSort(std::vector<SUnit> &sunits, SUnit *exitsu) 640249423Sdim : SUnits(sunits), ExitSU(exitsu) {} 641193323Sed 642193323SedScheduleHazardRecognizer::~ScheduleHazardRecognizer() {} 643