RegionInfo.cpp revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338
1//===- RegionInfo.cpp - SESE region detection analysis --------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// Detects single entry single exit regions in the control flow graph. 10//===----------------------------------------------------------------------===// 11 12#define DEBUG_TYPE "region" 13#include "llvm/Analysis/RegionInfo.h" 14#include "llvm/ADT/PostOrderIterator.h" 15#include "llvm/ADT/Statistic.h" 16#include "llvm/Analysis/LoopInfo.h" 17#include "llvm/Analysis/RegionIterator.h" 18#include "llvm/Support/CommandLine.h" 19#include "llvm/Support/Debug.h" 20#include "llvm/Support/ErrorHandling.h" 21#include <algorithm> 22#include <set> 23 24using namespace llvm; 25 26// Always verify if expensive checking is enabled. 27#ifdef XDEBUG 28static bool VerifyRegionInfo = true; 29#else 30static bool VerifyRegionInfo = false; 31#endif 32 33static cl::opt<bool,true> 34VerifyRegionInfoX("verify-region-info", cl::location(VerifyRegionInfo), 35 cl::desc("Verify region info (time consuming)")); 36 37STATISTIC(numRegions, "The # of regions"); 38STATISTIC(numSimpleRegions, "The # of simple regions"); 39 40static cl::opt<enum Region::PrintStyle> printStyle("print-region-style", 41 cl::Hidden, 42 cl::desc("style of printing regions"), 43 cl::values( 44 clEnumValN(Region::PrintNone, "none", "print no details"), 45 clEnumValN(Region::PrintBB, "bb", 46 "print regions in detail with block_iterator"), 47 clEnumValN(Region::PrintRN, "rn", 48 "print regions in detail with element_iterator"), 49 clEnumValEnd)); 50//===----------------------------------------------------------------------===// 51/// Region Implementation 52Region::Region(BasicBlock *Entry, BasicBlock *Exit, RegionInfo* RInfo, 53 DominatorTree *dt, Region *Parent) 54 : RegionNode(Parent, Entry, 1), RI(RInfo), DT(dt), exit(Exit) {} 55 56Region::~Region() { 57 // Free the cached nodes. 58 for (BBNodeMapT::iterator it = BBNodeMap.begin(), 59 ie = BBNodeMap.end(); it != ie; ++it) 60 delete it->second; 61 62 // Only clean the cache for this Region. Caches of child Regions will be 63 // cleaned when the child Regions are deleted. 64 BBNodeMap.clear(); 65 66 for (iterator I = begin(), E = end(); I != E; ++I) 67 delete *I; 68} 69 70void Region::replaceEntry(BasicBlock *BB) { 71 entry.setPointer(BB); 72} 73 74void Region::replaceExit(BasicBlock *BB) { 75 assert(exit && "No exit to replace!"); 76 exit = BB; 77} 78 79void Region::replaceEntryRecursive(BasicBlock *NewEntry) { 80 std::vector<Region *> RegionQueue; 81 BasicBlock *OldEntry = getEntry(); 82 83 RegionQueue.push_back(this); 84 while (!RegionQueue.empty()) { 85 Region *R = RegionQueue.back(); 86 RegionQueue.pop_back(); 87 88 R->replaceEntry(NewEntry); 89 for (Region::const_iterator RI = R->begin(), RE = R->end(); RI != RE; ++RI) 90 if ((*RI)->getEntry() == OldEntry) 91 RegionQueue.push_back(*RI); 92 } 93} 94 95void Region::replaceExitRecursive(BasicBlock *NewExit) { 96 std::vector<Region *> RegionQueue; 97 BasicBlock *OldExit = getExit(); 98 99 RegionQueue.push_back(this); 100 while (!RegionQueue.empty()) { 101 Region *R = RegionQueue.back(); 102 RegionQueue.pop_back(); 103 104 R->replaceExit(NewExit); 105 for (Region::const_iterator RI = R->begin(), RE = R->end(); RI != RE; ++RI) 106 if ((*RI)->getExit() == OldExit) 107 RegionQueue.push_back(*RI); 108 } 109} 110 111bool Region::contains(const BasicBlock *B) const { 112 BasicBlock *BB = const_cast<BasicBlock*>(B); 113 114 if (!DT->getNode(BB)) 115 return false; 116 117 BasicBlock *entry = getEntry(), *exit = getExit(); 118 119 // Toplevel region. 120 if (!exit) 121 return true; 122 123 return (DT->dominates(entry, BB) 124 && !(DT->dominates(exit, BB) && DT->dominates(entry, exit))); 125} 126 127bool Region::contains(const Loop *L) const { 128 // BBs that are not part of any loop are element of the Loop 129 // described by the NULL pointer. This loop is not part of any region, 130 // except if the region describes the whole function. 131 if (L == 0) 132 return getExit() == 0; 133 134 if (!contains(L->getHeader())) 135 return false; 136 137 SmallVector<BasicBlock *, 8> ExitingBlocks; 138 L->getExitingBlocks(ExitingBlocks); 139 140 for (SmallVectorImpl<BasicBlock*>::iterator BI = ExitingBlocks.begin(), 141 BE = ExitingBlocks.end(); BI != BE; ++BI) 142 if (!contains(*BI)) 143 return false; 144 145 return true; 146} 147 148Loop *Region::outermostLoopInRegion(Loop *L) const { 149 if (!contains(L)) 150 return 0; 151 152 while (L && contains(L->getParentLoop())) { 153 L = L->getParentLoop(); 154 } 155 156 return L; 157} 158 159Loop *Region::outermostLoopInRegion(LoopInfo *LI, BasicBlock* BB) const { 160 assert(LI && BB && "LI and BB cannot be null!"); 161 Loop *L = LI->getLoopFor(BB); 162 return outermostLoopInRegion(L); 163} 164 165BasicBlock *Region::getEnteringBlock() const { 166 BasicBlock *entry = getEntry(); 167 BasicBlock *Pred; 168 BasicBlock *enteringBlock = 0; 169 170 for (pred_iterator PI = pred_begin(entry), PE = pred_end(entry); PI != PE; 171 ++PI) { 172 Pred = *PI; 173 if (DT->getNode(Pred) && !contains(Pred)) { 174 if (enteringBlock) 175 return 0; 176 177 enteringBlock = Pred; 178 } 179 } 180 181 return enteringBlock; 182} 183 184BasicBlock *Region::getExitingBlock() const { 185 BasicBlock *exit = getExit(); 186 BasicBlock *Pred; 187 BasicBlock *exitingBlock = 0; 188 189 if (!exit) 190 return 0; 191 192 for (pred_iterator PI = pred_begin(exit), PE = pred_end(exit); PI != PE; 193 ++PI) { 194 Pred = *PI; 195 if (contains(Pred)) { 196 if (exitingBlock) 197 return 0; 198 199 exitingBlock = Pred; 200 } 201 } 202 203 return exitingBlock; 204} 205 206bool Region::isSimple() const { 207 return !isTopLevelRegion() && getEnteringBlock() && getExitingBlock(); 208} 209 210std::string Region::getNameStr() const { 211 std::string exitName; 212 std::string entryName; 213 214 if (getEntry()->getName().empty()) { 215 raw_string_ostream OS(entryName); 216 217 getEntry()->printAsOperand(OS, false); 218 } else 219 entryName = getEntry()->getName(); 220 221 if (getExit()) { 222 if (getExit()->getName().empty()) { 223 raw_string_ostream OS(exitName); 224 225 getExit()->printAsOperand(OS, false); 226 } else 227 exitName = getExit()->getName(); 228 } else 229 exitName = "<Function Return>"; 230 231 return entryName + " => " + exitName; 232} 233 234void Region::verifyBBInRegion(BasicBlock *BB) const { 235 if (!contains(BB)) 236 llvm_unreachable("Broken region found!"); 237 238 BasicBlock *entry = getEntry(), *exit = getExit(); 239 240 for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI) 241 if (!contains(*SI) && exit != *SI) 242 llvm_unreachable("Broken region found!"); 243 244 if (entry != BB) 245 for (pred_iterator SI = pred_begin(BB), SE = pred_end(BB); SI != SE; ++SI) 246 if (!contains(*SI)) 247 llvm_unreachable("Broken region found!"); 248} 249 250void Region::verifyWalk(BasicBlock *BB, std::set<BasicBlock*> *visited) const { 251 BasicBlock *exit = getExit(); 252 253 visited->insert(BB); 254 255 verifyBBInRegion(BB); 256 257 for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI) 258 if (*SI != exit && visited->find(*SI) == visited->end()) 259 verifyWalk(*SI, visited); 260} 261 262void Region::verifyRegion() const { 263 // Only do verification when user wants to, otherwise this expensive 264 // check will be invoked by PassManager. 265 if (!VerifyRegionInfo) return; 266 267 std::set<BasicBlock*> visited; 268 verifyWalk(getEntry(), &visited); 269} 270 271void Region::verifyRegionNest() const { 272 for (Region::const_iterator RI = begin(), RE = end(); RI != RE; ++RI) 273 (*RI)->verifyRegionNest(); 274 275 verifyRegion(); 276} 277 278Region::element_iterator Region::element_begin() { 279 return GraphTraits<Region*>::nodes_begin(this); 280} 281 282Region::element_iterator Region::element_end() { 283 return GraphTraits<Region*>::nodes_end(this); 284} 285 286Region::const_element_iterator Region::element_begin() const { 287 return GraphTraits<const Region*>::nodes_begin(this); 288} 289 290Region::const_element_iterator Region::element_end() const { 291 return GraphTraits<const Region*>::nodes_end(this); 292} 293 294Region* Region::getSubRegionNode(BasicBlock *BB) const { 295 Region *R = RI->getRegionFor(BB); 296 297 if (!R || R == this) 298 return 0; 299 300 // If we pass the BB out of this region, that means our code is broken. 301 assert(contains(R) && "BB not in current region!"); 302 303 while (contains(R->getParent()) && R->getParent() != this) 304 R = R->getParent(); 305 306 if (R->getEntry() != BB) 307 return 0; 308 309 return R; 310} 311 312RegionNode* Region::getBBNode(BasicBlock *BB) const { 313 assert(contains(BB) && "Can get BB node out of this region!"); 314 315 BBNodeMapT::const_iterator at = BBNodeMap.find(BB); 316 317 if (at != BBNodeMap.end()) 318 return at->second; 319 320 RegionNode *NewNode = new RegionNode(const_cast<Region*>(this), BB); 321 BBNodeMap.insert(std::make_pair(BB, NewNode)); 322 return NewNode; 323} 324 325RegionNode* Region::getNode(BasicBlock *BB) const { 326 assert(contains(BB) && "Can get BB node out of this region!"); 327 if (Region* Child = getSubRegionNode(BB)) 328 return Child->getNode(); 329 330 return getBBNode(BB); 331} 332 333void Region::transferChildrenTo(Region *To) { 334 for (iterator I = begin(), E = end(); I != E; ++I) { 335 (*I)->parent = To; 336 To->children.push_back(*I); 337 } 338 children.clear(); 339} 340 341void Region::addSubRegion(Region *SubRegion, bool moveChildren) { 342 assert(SubRegion->parent == 0 && "SubRegion already has a parent!"); 343 assert(std::find(begin(), end(), SubRegion) == children.end() 344 && "Subregion already exists!"); 345 346 SubRegion->parent = this; 347 children.push_back(SubRegion); 348 349 if (!moveChildren) 350 return; 351 352 assert(SubRegion->children.size() == 0 353 && "SubRegions that contain children are not supported"); 354 355 for (element_iterator I = element_begin(), E = element_end(); I != E; ++I) 356 if (!(*I)->isSubRegion()) { 357 BasicBlock *BB = (*I)->getNodeAs<BasicBlock>(); 358 359 if (SubRegion->contains(BB)) 360 RI->setRegionFor(BB, SubRegion); 361 } 362 363 std::vector<Region*> Keep; 364 for (iterator I = begin(), E = end(); I != E; ++I) 365 if (SubRegion->contains(*I) && *I != SubRegion) { 366 SubRegion->children.push_back(*I); 367 (*I)->parent = SubRegion; 368 } else 369 Keep.push_back(*I); 370 371 children.clear(); 372 children.insert(children.begin(), Keep.begin(), Keep.end()); 373} 374 375 376Region *Region::removeSubRegion(Region *Child) { 377 assert(Child->parent == this && "Child is not a child of this region!"); 378 Child->parent = 0; 379 RegionSet::iterator I = std::find(children.begin(), children.end(), Child); 380 assert(I != children.end() && "Region does not exit. Unable to remove."); 381 children.erase(children.begin()+(I-begin())); 382 return Child; 383} 384 385unsigned Region::getDepth() const { 386 unsigned Depth = 0; 387 388 for (Region *R = parent; R != 0; R = R->parent) 389 ++Depth; 390 391 return Depth; 392} 393 394Region *Region::getExpandedRegion() const { 395 unsigned NumSuccessors = exit->getTerminator()->getNumSuccessors(); 396 397 if (NumSuccessors == 0) 398 return NULL; 399 400 for (pred_iterator PI = pred_begin(getExit()), PE = pred_end(getExit()); 401 PI != PE; ++PI) 402 if (!DT->dominates(getEntry(), *PI)) 403 return NULL; 404 405 Region *R = RI->getRegionFor(exit); 406 407 if (R->getEntry() != exit) { 408 if (exit->getTerminator()->getNumSuccessors() == 1) 409 return new Region(getEntry(), *succ_begin(exit), RI, DT); 410 else 411 return NULL; 412 } 413 414 while (R->getParent() && R->getParent()->getEntry() == exit) 415 R = R->getParent(); 416 417 if (!DT->dominates(getEntry(), R->getExit())) 418 for (pred_iterator PI = pred_begin(getExit()), PE = pred_end(getExit()); 419 PI != PE; ++PI) 420 if (!DT->dominates(R->getExit(), *PI)) 421 return NULL; 422 423 return new Region(getEntry(), R->getExit(), RI, DT); 424} 425 426void Region::print(raw_ostream &OS, bool print_tree, unsigned level, 427 enum PrintStyle Style) const { 428 if (print_tree) 429 OS.indent(level*2) << "[" << level << "] " << getNameStr(); 430 else 431 OS.indent(level*2) << getNameStr(); 432 433 OS << "\n"; 434 435 436 if (Style != PrintNone) { 437 OS.indent(level*2) << "{\n"; 438 OS.indent(level*2 + 2); 439 440 if (Style == PrintBB) { 441 for (const auto &BB : blocks()) 442 OS << BB->getName() << ", "; // TODO: remove the last "," 443 } else if (Style == PrintRN) { 444 for (const_element_iterator I = element_begin(), E = element_end(); I!=E; ++I) 445 OS << **I << ", "; // TODO: remove the last ", 446 } 447 448 OS << "\n"; 449 } 450 451 if (print_tree) 452 for (const_iterator RI = begin(), RE = end(); RI != RE; ++RI) 453 (*RI)->print(OS, print_tree, level+1, Style); 454 455 if (Style != PrintNone) 456 OS.indent(level*2) << "} \n"; 457} 458 459#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 460void Region::dump() const { 461 print(dbgs(), true, getDepth(), printStyle.getValue()); 462} 463#endif 464 465void Region::clearNodeCache() { 466 // Free the cached nodes. 467 for (BBNodeMapT::iterator I = BBNodeMap.begin(), 468 IE = BBNodeMap.end(); I != IE; ++I) 469 delete I->second; 470 471 BBNodeMap.clear(); 472 for (Region::iterator RI = begin(), RE = end(); RI != RE; ++RI) 473 (*RI)->clearNodeCache(); 474} 475 476//===----------------------------------------------------------------------===// 477// RegionInfo implementation 478// 479 480bool RegionInfo::isCommonDomFrontier(BasicBlock *BB, BasicBlock *entry, 481 BasicBlock *exit) const { 482 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) { 483 BasicBlock *P = *PI; 484 if (DT->dominates(entry, P) && !DT->dominates(exit, P)) 485 return false; 486 } 487 return true; 488} 489 490bool RegionInfo::isRegion(BasicBlock *entry, BasicBlock *exit) const { 491 assert(entry && exit && "entry and exit must not be null!"); 492 typedef DominanceFrontier::DomSetType DST; 493 494 DST *entrySuccs = &DF->find(entry)->second; 495 496 // Exit is the header of a loop that contains the entry. In this case, 497 // the dominance frontier must only contain the exit. 498 if (!DT->dominates(entry, exit)) { 499 for (DST::iterator SI = entrySuccs->begin(), SE = entrySuccs->end(); 500 SI != SE; ++SI) 501 if (*SI != exit && *SI != entry) 502 return false; 503 504 return true; 505 } 506 507 DST *exitSuccs = &DF->find(exit)->second; 508 509 // Do not allow edges leaving the region. 510 for (DST::iterator SI = entrySuccs->begin(), SE = entrySuccs->end(); 511 SI != SE; ++SI) { 512 if (*SI == exit || *SI == entry) 513 continue; 514 if (exitSuccs->find(*SI) == exitSuccs->end()) 515 return false; 516 if (!isCommonDomFrontier(*SI, entry, exit)) 517 return false; 518 } 519 520 // Do not allow edges pointing into the region. 521 for (DST::iterator SI = exitSuccs->begin(), SE = exitSuccs->end(); 522 SI != SE; ++SI) 523 if (DT->properlyDominates(entry, *SI) && *SI != exit) 524 return false; 525 526 527 return true; 528} 529 530void RegionInfo::insertShortCut(BasicBlock *entry, BasicBlock *exit, 531 BBtoBBMap *ShortCut) const { 532 assert(entry && exit && "entry and exit must not be null!"); 533 534 BBtoBBMap::iterator e = ShortCut->find(exit); 535 536 if (e == ShortCut->end()) 537 // No further region at exit available. 538 (*ShortCut)[entry] = exit; 539 else { 540 // We found a region e that starts at exit. Therefore (entry, e->second) 541 // is also a region, that is larger than (entry, exit). Insert the 542 // larger one. 543 BasicBlock *BB = e->second; 544 (*ShortCut)[entry] = BB; 545 } 546} 547 548DomTreeNode* RegionInfo::getNextPostDom(DomTreeNode* N, 549 BBtoBBMap *ShortCut) const { 550 BBtoBBMap::iterator e = ShortCut->find(N->getBlock()); 551 552 if (e == ShortCut->end()) 553 return N->getIDom(); 554 555 return PDT->getNode(e->second)->getIDom(); 556} 557 558bool RegionInfo::isTrivialRegion(BasicBlock *entry, BasicBlock *exit) const { 559 assert(entry && exit && "entry and exit must not be null!"); 560 561 unsigned num_successors = succ_end(entry) - succ_begin(entry); 562 563 if (num_successors <= 1 && exit == *(succ_begin(entry))) 564 return true; 565 566 return false; 567} 568 569void RegionInfo::updateStatistics(Region *R) { 570 ++numRegions; 571 572 // TODO: Slow. Should only be enabled if -stats is used. 573 if (R->isSimple()) ++numSimpleRegions; 574} 575 576Region *RegionInfo::createRegion(BasicBlock *entry, BasicBlock *exit) { 577 assert(entry && exit && "entry and exit must not be null!"); 578 579 if (isTrivialRegion(entry, exit)) 580 return 0; 581 582 Region *region = new Region(entry, exit, this, DT); 583 BBtoRegion.insert(std::make_pair(entry, region)); 584 585 #ifdef XDEBUG 586 region->verifyRegion(); 587 #else 588 DEBUG(region->verifyRegion()); 589 #endif 590 591 updateStatistics(region); 592 return region; 593} 594 595void RegionInfo::findRegionsWithEntry(BasicBlock *entry, BBtoBBMap *ShortCut) { 596 assert(entry); 597 598 DomTreeNode *N = PDT->getNode(entry); 599 600 if (!N) 601 return; 602 603 Region *lastRegion= 0; 604 BasicBlock *lastExit = entry; 605 606 // As only a BasicBlock that postdominates entry can finish a region, walk the 607 // post dominance tree upwards. 608 while ((N = getNextPostDom(N, ShortCut))) { 609 BasicBlock *exit = N->getBlock(); 610 611 if (!exit) 612 break; 613 614 if (isRegion(entry, exit)) { 615 Region *newRegion = createRegion(entry, exit); 616 617 if (lastRegion) 618 newRegion->addSubRegion(lastRegion); 619 620 lastRegion = newRegion; 621 lastExit = exit; 622 } 623 624 // This can never be a region, so stop the search. 625 if (!DT->dominates(entry, exit)) 626 break; 627 } 628 629 // Tried to create regions from entry to lastExit. Next time take a 630 // shortcut from entry to lastExit. 631 if (lastExit != entry) 632 insertShortCut(entry, lastExit, ShortCut); 633} 634 635void RegionInfo::scanForRegions(Function &F, BBtoBBMap *ShortCut) { 636 BasicBlock *entry = &(F.getEntryBlock()); 637 DomTreeNode *N = DT->getNode(entry); 638 639 // Iterate over the dominance tree in post order to start with the small 640 // regions from the bottom of the dominance tree. If the small regions are 641 // detected first, detection of bigger regions is faster, as we can jump 642 // over the small regions. 643 for (po_iterator<DomTreeNode*> FI = po_begin(N), FE = po_end(N); FI != FE; 644 ++FI) { 645 findRegionsWithEntry(FI->getBlock(), ShortCut); 646 } 647} 648 649Region *RegionInfo::getTopMostParent(Region *region) { 650 while (region->parent) 651 region = region->getParent(); 652 653 return region; 654} 655 656void RegionInfo::buildRegionsTree(DomTreeNode *N, Region *region) { 657 BasicBlock *BB = N->getBlock(); 658 659 // Passed region exit 660 while (BB == region->getExit()) 661 region = region->getParent(); 662 663 BBtoRegionMap::iterator it = BBtoRegion.find(BB); 664 665 // This basic block is a start block of a region. It is already in the 666 // BBtoRegion relation. Only the child basic blocks have to be updated. 667 if (it != BBtoRegion.end()) { 668 Region *newRegion = it->second; 669 region->addSubRegion(getTopMostParent(newRegion)); 670 region = newRegion; 671 } else { 672 BBtoRegion[BB] = region; 673 } 674 675 for (DomTreeNode::iterator CI = N->begin(), CE = N->end(); CI != CE; ++CI) 676 buildRegionsTree(*CI, region); 677} 678 679void RegionInfo::releaseMemory() { 680 BBtoRegion.clear(); 681 if (TopLevelRegion) 682 delete TopLevelRegion; 683 TopLevelRegion = 0; 684} 685 686RegionInfo::RegionInfo() : FunctionPass(ID) { 687 initializeRegionInfoPass(*PassRegistry::getPassRegistry()); 688 TopLevelRegion = 0; 689} 690 691RegionInfo::~RegionInfo() { 692 releaseMemory(); 693} 694 695void RegionInfo::Calculate(Function &F) { 696 // ShortCut a function where for every BB the exit of the largest region 697 // starting with BB is stored. These regions can be threated as single BBS. 698 // This improves performance on linear CFGs. 699 BBtoBBMap ShortCut; 700 701 scanForRegions(F, &ShortCut); 702 BasicBlock *BB = &F.getEntryBlock(); 703 buildRegionsTree(DT->getNode(BB), TopLevelRegion); 704} 705 706bool RegionInfo::runOnFunction(Function &F) { 707 releaseMemory(); 708 709 DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree(); 710 PDT = &getAnalysis<PostDominatorTree>(); 711 DF = &getAnalysis<DominanceFrontier>(); 712 713 TopLevelRegion = new Region(&F.getEntryBlock(), 0, this, DT, 0); 714 updateStatistics(TopLevelRegion); 715 716 Calculate(F); 717 718 return false; 719} 720 721void RegionInfo::getAnalysisUsage(AnalysisUsage &AU) const { 722 AU.setPreservesAll(); 723 AU.addRequiredTransitive<DominatorTreeWrapperPass>(); 724 AU.addRequired<PostDominatorTree>(); 725 AU.addRequired<DominanceFrontier>(); 726} 727 728void RegionInfo::print(raw_ostream &OS, const Module *) const { 729 OS << "Region tree:\n"; 730 TopLevelRegion->print(OS, true, 0, printStyle.getValue()); 731 OS << "End region tree\n"; 732} 733 734void RegionInfo::verifyAnalysis() const { 735 // Only do verification when user wants to, otherwise this expensive check 736 // will be invoked by PMDataManager::verifyPreservedAnalysis when 737 // a regionpass (marked PreservedAll) finish. 738 if (!VerifyRegionInfo) return; 739 740 TopLevelRegion->verifyRegionNest(); 741} 742 743// Region pass manager support. 744Region *RegionInfo::getRegionFor(BasicBlock *BB) const { 745 BBtoRegionMap::const_iterator I= 746 BBtoRegion.find(BB); 747 return I != BBtoRegion.end() ? I->second : 0; 748} 749 750void RegionInfo::setRegionFor(BasicBlock *BB, Region *R) { 751 BBtoRegion[BB] = R; 752} 753 754Region *RegionInfo::operator[](BasicBlock *BB) const { 755 return getRegionFor(BB); 756} 757 758BasicBlock *RegionInfo::getMaxRegionExit(BasicBlock *BB) const { 759 BasicBlock *Exit = NULL; 760 761 while (true) { 762 // Get largest region that starts at BB. 763 Region *R = getRegionFor(BB); 764 while (R && R->getParent() && R->getParent()->getEntry() == BB) 765 R = R->getParent(); 766 767 // Get the single exit of BB. 768 if (R && R->getEntry() == BB) 769 Exit = R->getExit(); 770 else if (++succ_begin(BB) == succ_end(BB)) 771 Exit = *succ_begin(BB); 772 else // No single exit exists. 773 return Exit; 774 775 // Get largest region that starts at Exit. 776 Region *ExitR = getRegionFor(Exit); 777 while (ExitR && ExitR->getParent() 778 && ExitR->getParent()->getEntry() == Exit) 779 ExitR = ExitR->getParent(); 780 781 for (pred_iterator PI = pred_begin(Exit), PE = pred_end(Exit); PI != PE; 782 ++PI) 783 if (!R->contains(*PI) && !ExitR->contains(*PI)) 784 break; 785 786 // This stops infinite cycles. 787 if (DT->dominates(Exit, BB)) 788 break; 789 790 BB = Exit; 791 } 792 793 return Exit; 794} 795 796Region* 797RegionInfo::getCommonRegion(Region *A, Region *B) const { 798 assert (A && B && "One of the Regions is NULL"); 799 800 if (A->contains(B)) return A; 801 802 while (!B->contains(A)) 803 B = B->getParent(); 804 805 return B; 806} 807 808Region* 809RegionInfo::getCommonRegion(SmallVectorImpl<Region*> &Regions) const { 810 Region* ret = Regions.back(); 811 Regions.pop_back(); 812 813 for (SmallVectorImpl<Region*>::const_iterator I = Regions.begin(), 814 E = Regions.end(); I != E; ++I) 815 ret = getCommonRegion(ret, *I); 816 817 return ret; 818} 819 820Region* 821RegionInfo::getCommonRegion(SmallVectorImpl<BasicBlock*> &BBs) const { 822 Region* ret = getRegionFor(BBs.back()); 823 BBs.pop_back(); 824 825 for (SmallVectorImpl<BasicBlock*>::const_iterator I = BBs.begin(), 826 E = BBs.end(); I != E; ++I) 827 ret = getCommonRegion(ret, getRegionFor(*I)); 828 829 return ret; 830} 831 832void RegionInfo::splitBlock(BasicBlock* NewBB, BasicBlock *OldBB) 833{ 834 Region *R = getRegionFor(OldBB); 835 836 setRegionFor(NewBB, R); 837 838 while (R->getEntry() == OldBB && !R->isTopLevelRegion()) { 839 R->replaceEntry(NewBB); 840 R = R->getParent(); 841 } 842 843 setRegionFor(OldBB, R); 844} 845 846char RegionInfo::ID = 0; 847INITIALIZE_PASS_BEGIN(RegionInfo, "regions", 848 "Detect single entry single exit regions", true, true) 849INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) 850INITIALIZE_PASS_DEPENDENCY(PostDominatorTree) 851INITIALIZE_PASS_DEPENDENCY(DominanceFrontier) 852INITIALIZE_PASS_END(RegionInfo, "regions", 853 "Detect single entry single exit regions", true, true) 854 855// Create methods available outside of this file, to use them 856// "include/llvm/LinkAllPasses.h". Otherwise the pass would be deleted by 857// the link time optimization. 858 859namespace llvm { 860 FunctionPass *createRegionInfoPass() { 861 return new RegionInfo(); 862 } 863} 864 865