1//===- RegionInfoImpl.h - SESE region detection analysis --------*- C++ -*-===//
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#ifndef LLVM_ANALYSIS_REGIONINFOIMPL_H
13#define LLVM_ANALYSIS_REGIONINFOIMPL_H
14
15#include "llvm/ADT/PostOrderIterator.h"
16#include "llvm/Analysis/DominanceFrontier.h"
17#include "llvm/Analysis/LoopInfo.h"
18#include "llvm/Analysis/PostDominators.h"
19#include "llvm/Analysis/RegionInfo.h"
20#include "llvm/Analysis/RegionIterator.h"
21#include "llvm/Support/Debug.h"
22#include "llvm/Support/ErrorHandling.h"
23#include <algorithm>
24#include <iterator>
25#include <set>
26
27namespace llvm {
28
29#define DEBUG_TYPE "region"
30
31//===----------------------------------------------------------------------===//
32/// RegionBase Implementation
33template <class Tr>
34RegionBase<Tr>::RegionBase(BlockT *Entry, BlockT *Exit,
35                           typename Tr::RegionInfoT *RInfo, DomTreeT *dt,
36                           RegionT *Parent)
37    : RegionNodeBase<Tr>(Parent, Entry, 1), RI(RInfo), DT(dt), exit(Exit) {}
38
39template <class Tr>
40RegionBase<Tr>::~RegionBase() {
41  // Only clean the cache for this Region. Caches of child Regions will be
42  // cleaned when the child Regions are deleted.
43  BBNodeMap.clear();
44}
45
46template <class Tr>
47void RegionBase<Tr>::replaceEntry(BlockT *BB) {
48  this->entry.setPointer(BB);
49}
50
51template <class Tr>
52void RegionBase<Tr>::replaceExit(BlockT *BB) {
53  assert(exit && "No exit to replace!");
54  exit = BB;
55}
56
57template <class Tr>
58void RegionBase<Tr>::replaceEntryRecursive(BlockT *NewEntry) {
59  std::vector<RegionT *> RegionQueue;
60  BlockT *OldEntry = getEntry();
61
62  RegionQueue.push_back(static_cast<RegionT *>(this));
63  while (!RegionQueue.empty()) {
64    RegionT *R = RegionQueue.back();
65    RegionQueue.pop_back();
66
67    R->replaceEntry(NewEntry);
68    for (std::unique_ptr<RegionT> &Child : *R) {
69      if (Child->getEntry() == OldEntry)
70        RegionQueue.push_back(Child.get());
71    }
72  }
73}
74
75template <class Tr>
76void RegionBase<Tr>::replaceExitRecursive(BlockT *NewExit) {
77  std::vector<RegionT *> RegionQueue;
78  BlockT *OldExit = getExit();
79
80  RegionQueue.push_back(static_cast<RegionT *>(this));
81  while (!RegionQueue.empty()) {
82    RegionT *R = RegionQueue.back();
83    RegionQueue.pop_back();
84
85    R->replaceExit(NewExit);
86    for (std::unique_ptr<RegionT> &Child : *R) {
87      if (Child->getExit() == OldExit)
88        RegionQueue.push_back(Child.get());
89    }
90  }
91}
92
93template <class Tr>
94bool RegionBase<Tr>::contains(const BlockT *B) const {
95  BlockT *BB = const_cast<BlockT *>(B);
96
97  if (!DT->getNode(BB))
98    return false;
99
100  BlockT *entry = getEntry(), *exit = getExit();
101
102  // Toplevel region.
103  if (!exit)
104    return true;
105
106  return (DT->dominates(entry, BB) &&
107          !(DT->dominates(exit, BB) && DT->dominates(entry, exit)));
108}
109
110template <class Tr>
111bool RegionBase<Tr>::contains(const LoopT *L) const {
112  // BBs that are not part of any loop are element of the Loop
113  // described by the NULL pointer. This loop is not part of any region,
114  // except if the region describes the whole function.
115  if (!L)
116    return getExit() == nullptr;
117
118  if (!contains(L->getHeader()))
119    return false;
120
121  SmallVector<BlockT *, 8> ExitingBlocks;
122  L->getExitingBlocks(ExitingBlocks);
123
124  for (BlockT *BB : ExitingBlocks) {
125    if (!contains(BB))
126      return false;
127  }
128
129  return true;
130}
131
132template <class Tr>
133typename Tr::LoopT *RegionBase<Tr>::outermostLoopInRegion(LoopT *L) const {
134  if (!contains(L))
135    return nullptr;
136
137  while (L && contains(L->getParentLoop())) {
138    L = L->getParentLoop();
139  }
140
141  return L;
142}
143
144template <class Tr>
145typename Tr::LoopT *RegionBase<Tr>::outermostLoopInRegion(LoopInfoT *LI,
146                                                          BlockT *BB) const {
147  assert(LI && BB && "LI and BB cannot be null!");
148  LoopT *L = LI->getLoopFor(BB);
149  return outermostLoopInRegion(L);
150}
151
152template <class Tr>
153typename RegionBase<Tr>::BlockT *RegionBase<Tr>::getEnteringBlock() const {
154  BlockT *entry = getEntry();
155  BlockT *enteringBlock = nullptr;
156
157  for (BlockT *Pred : make_range(InvBlockTraits::child_begin(entry),
158                                 InvBlockTraits::child_end(entry))) {
159    if (DT->getNode(Pred) && !contains(Pred)) {
160      if (enteringBlock)
161        return nullptr;
162
163      enteringBlock = Pred;
164    }
165  }
166
167  return enteringBlock;
168}
169
170template <class Tr>
171typename RegionBase<Tr>::BlockT *RegionBase<Tr>::getExitingBlock() const {
172  BlockT *exit = getExit();
173  BlockT *exitingBlock = nullptr;
174
175  if (!exit)
176    return nullptr;
177
178  for (BlockT *Pred : make_range(InvBlockTraits::child_begin(exit),
179                                 InvBlockTraits::child_end(exit))) {
180    if (contains(Pred)) {
181      if (exitingBlock)
182        return nullptr;
183
184      exitingBlock = Pred;
185    }
186  }
187
188  return exitingBlock;
189}
190
191template <class Tr>
192bool RegionBase<Tr>::isSimple() const {
193  return !isTopLevelRegion() && getEnteringBlock() && getExitingBlock();
194}
195
196template <class Tr>
197std::string RegionBase<Tr>::getNameStr() const {
198  std::string exitName;
199  std::string entryName;
200
201  if (getEntry()->getName().empty()) {
202    raw_string_ostream OS(entryName);
203
204    getEntry()->printAsOperand(OS, false);
205  } else
206    entryName = getEntry()->getName();
207
208  if (getExit()) {
209    if (getExit()->getName().empty()) {
210      raw_string_ostream OS(exitName);
211
212      getExit()->printAsOperand(OS, false);
213    } else
214      exitName = getExit()->getName();
215  } else
216    exitName = "<Function Return>";
217
218  return entryName + " => " + exitName;
219}
220
221template <class Tr>
222void RegionBase<Tr>::verifyBBInRegion(BlockT *BB) const {
223  if (!contains(BB))
224    llvm_unreachable("Broken region found: enumerated BB not in region!");
225
226  BlockT *entry = getEntry(), *exit = getExit();
227
228  for (BlockT *Succ :
229       make_range(BlockTraits::child_begin(BB), BlockTraits::child_end(BB))) {
230    if (!contains(Succ) && exit != Succ)
231      llvm_unreachable("Broken region found: edges leaving the region must go "
232                       "to the exit node!");
233  }
234
235  if (entry != BB) {
236    for (BlockT *Pred : make_range(InvBlockTraits::child_begin(BB),
237                                   InvBlockTraits::child_end(BB))) {
238      if (!contains(Pred))
239        llvm_unreachable("Broken region found: edges entering the region must "
240                         "go to the entry node!");
241    }
242  }
243}
244
245template <class Tr>
246void RegionBase<Tr>::verifyWalk(BlockT *BB, std::set<BlockT *> *visited) const {
247  BlockT *exit = getExit();
248
249  visited->insert(BB);
250
251  verifyBBInRegion(BB);
252
253  for (BlockT *Succ :
254       make_range(BlockTraits::child_begin(BB), BlockTraits::child_end(BB))) {
255    if (Succ != exit && visited->find(Succ) == visited->end())
256      verifyWalk(Succ, visited);
257  }
258}
259
260template <class Tr>
261void RegionBase<Tr>::verifyRegion() const {
262  // Only do verification when user wants to, otherwise this expensive check
263  // will be invoked by PMDataManager::verifyPreservedAnalysis when
264  // a regionpass (marked PreservedAll) finish.
265  if (!RegionInfoBase<Tr>::VerifyRegionInfo)
266    return;
267
268  std::set<BlockT *> visited;
269  verifyWalk(getEntry(), &visited);
270}
271
272template <class Tr>
273void RegionBase<Tr>::verifyRegionNest() const {
274  for (const std::unique_ptr<RegionT> &R : *this)
275    R->verifyRegionNest();
276
277  verifyRegion();
278}
279
280template <class Tr>
281typename RegionBase<Tr>::element_iterator RegionBase<Tr>::element_begin() {
282  return GraphTraits<RegionT *>::nodes_begin(static_cast<RegionT *>(this));
283}
284
285template <class Tr>
286typename RegionBase<Tr>::element_iterator RegionBase<Tr>::element_end() {
287  return GraphTraits<RegionT *>::nodes_end(static_cast<RegionT *>(this));
288}
289
290template <class Tr>
291typename RegionBase<Tr>::const_element_iterator
292RegionBase<Tr>::element_begin() const {
293  return GraphTraits<const RegionT *>::nodes_begin(
294      static_cast<const RegionT *>(this));
295}
296
297template <class Tr>
298typename RegionBase<Tr>::const_element_iterator
299RegionBase<Tr>::element_end() const {
300  return GraphTraits<const RegionT *>::nodes_end(
301      static_cast<const RegionT *>(this));
302}
303
304template <class Tr>
305typename Tr::RegionT *RegionBase<Tr>::getSubRegionNode(BlockT *BB) const {
306  typedef typename Tr::RegionT RegionT;
307  RegionT *R = RI->getRegionFor(BB);
308
309  if (!R || R == this)
310    return nullptr;
311
312  // If we pass the BB out of this region, that means our code is broken.
313  assert(contains(R) && "BB not in current region!");
314
315  while (contains(R->getParent()) && R->getParent() != this)
316    R = R->getParent();
317
318  if (R->getEntry() != BB)
319    return nullptr;
320
321  return R;
322}
323
324template <class Tr>
325typename Tr::RegionNodeT *RegionBase<Tr>::getBBNode(BlockT *BB) const {
326  assert(contains(BB) && "Can get BB node out of this region!");
327
328  typename BBNodeMapT::const_iterator at = BBNodeMap.find(BB);
329
330  if (at == BBNodeMap.end()) {
331    auto Deconst = const_cast<RegionBase<Tr> *>(this);
332    typename BBNodeMapT::value_type V = {
333        BB, make_unique<RegionNodeT>(static_cast<RegionT *>(Deconst), BB)};
334    at = BBNodeMap.insert(std::move(V)).first;
335  }
336  return at->second.get();
337}
338
339template <class Tr>
340typename Tr::RegionNodeT *RegionBase<Tr>::getNode(BlockT *BB) const {
341  assert(contains(BB) && "Can get BB node out of this region!");
342  if (RegionT *Child = getSubRegionNode(BB))
343    return Child->getNode();
344
345  return getBBNode(BB);
346}
347
348template <class Tr>
349void RegionBase<Tr>::transferChildrenTo(RegionT *To) {
350  for (std::unique_ptr<RegionT> &R : *this) {
351    R->parent = To;
352    To->children.push_back(std::move(R));
353  }
354  children.clear();
355}
356
357template <class Tr>
358void RegionBase<Tr>::addSubRegion(RegionT *SubRegion, bool moveChildren) {
359  assert(!SubRegion->parent && "SubRegion already has a parent!");
360  assert(find_if(*this,
361                 [&](const std::unique_ptr<RegionT> &R) {
362                   return R.get() == SubRegion;
363                 }) == children.end() &&
364         "Subregion already exists!");
365
366  SubRegion->parent = static_cast<RegionT *>(this);
367  children.push_back(std::unique_ptr<RegionT>(SubRegion));
368
369  if (!moveChildren)
370    return;
371
372  assert(SubRegion->children.empty() &&
373         "SubRegions that contain children are not supported");
374
375  for (RegionNodeT *Element : elements()) {
376    if (!Element->isSubRegion()) {
377      BlockT *BB = Element->template getNodeAs<BlockT>();
378
379      if (SubRegion->contains(BB))
380        RI->setRegionFor(BB, SubRegion);
381    }
382  }
383
384  std::vector<std::unique_ptr<RegionT>> Keep;
385  for (std::unique_ptr<RegionT> &R : *this) {
386    if (SubRegion->contains(R.get()) && R.get() != SubRegion) {
387      R->parent = SubRegion;
388      SubRegion->children.push_back(std::move(R));
389    } else
390      Keep.push_back(std::move(R));
391  }
392
393  children.clear();
394  children.insert(
395      children.begin(),
396      std::move_iterator<typename RegionSet::iterator>(Keep.begin()),
397      std::move_iterator<typename RegionSet::iterator>(Keep.end()));
398}
399
400template <class Tr>
401typename Tr::RegionT *RegionBase<Tr>::removeSubRegion(RegionT *Child) {
402  assert(Child->parent == this && "Child is not a child of this region!");
403  Child->parent = nullptr;
404  typename RegionSet::iterator I =
405      find_if(children, [&](const std::unique_ptr<RegionT> &R) {
406        return R.get() == Child;
407      });
408  assert(I != children.end() && "Region does not exit. Unable to remove.");
409  children.erase(children.begin() + (I - begin()));
410  return Child;
411}
412
413template <class Tr>
414unsigned RegionBase<Tr>::getDepth() const {
415  unsigned Depth = 0;
416
417  for (RegionT *R = getParent(); R != nullptr; R = R->getParent())
418    ++Depth;
419
420  return Depth;
421}
422
423template <class Tr>
424typename Tr::RegionT *RegionBase<Tr>::getExpandedRegion() const {
425  unsigned NumSuccessors = Tr::getNumSuccessors(exit);
426
427  if (NumSuccessors == 0)
428    return nullptr;
429
430  RegionT *R = RI->getRegionFor(exit);
431
432  if (R->getEntry() != exit) {
433    for (BlockT *Pred : make_range(InvBlockTraits::child_begin(getExit()),
434                                   InvBlockTraits::child_end(getExit())))
435      if (!contains(Pred))
436        return nullptr;
437    if (Tr::getNumSuccessors(exit) == 1)
438      return new RegionT(getEntry(), *BlockTraits::child_begin(exit), RI, DT);
439    return nullptr;
440  }
441
442  while (R->getParent() && R->getParent()->getEntry() == exit)
443    R = R->getParent();
444
445  for (BlockT *Pred : make_range(InvBlockTraits::child_begin(getExit()),
446                                 InvBlockTraits::child_end(getExit()))) {
447    if (!(contains(Pred) || R->contains(Pred)))
448      return nullptr;
449  }
450
451  return new RegionT(getEntry(), R->getExit(), RI, DT);
452}
453
454template <class Tr>
455void RegionBase<Tr>::print(raw_ostream &OS, bool print_tree, unsigned level,
456                           PrintStyle Style) const {
457  if (print_tree)
458    OS.indent(level * 2) << '[' << level << "] " << getNameStr();
459  else
460    OS.indent(level * 2) << getNameStr();
461
462  OS << '\n';
463
464  if (Style != PrintNone) {
465    OS.indent(level * 2) << "{\n";
466    OS.indent(level * 2 + 2);
467
468    if (Style == PrintBB) {
469      for (const auto *BB : blocks())
470        OS << BB->getName() << ", "; // TODO: remove the last ","
471    } else if (Style == PrintRN) {
472      for (const RegionNodeT *Element : elements()) {
473        OS << *Element << ", "; // TODO: remove the last ",
474      }
475    }
476
477    OS << '\n';
478  }
479
480  if (print_tree) {
481    for (const std::unique_ptr<RegionT> &R : *this)
482      R->print(OS, print_tree, level + 1, Style);
483  }
484
485  if (Style != PrintNone)
486    OS.indent(level * 2) << "} \n";
487}
488
489#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
490template <class Tr>
491void RegionBase<Tr>::dump() const {
492  print(dbgs(), true, getDepth(), RegionInfoBase<Tr>::printStyle);
493}
494#endif
495
496template <class Tr>
497void RegionBase<Tr>::clearNodeCache() {
498  BBNodeMap.clear();
499  for (std::unique_ptr<RegionT> &R : *this)
500    R->clearNodeCache();
501}
502
503//===----------------------------------------------------------------------===//
504// RegionInfoBase implementation
505//
506
507template <class Tr>
508RegionInfoBase<Tr>::RegionInfoBase()
509    : TopLevelRegion(nullptr) {}
510
511template <class Tr>
512RegionInfoBase<Tr>::~RegionInfoBase() {
513  releaseMemory();
514}
515
516template <class Tr>
517void RegionInfoBase<Tr>::verifyBBMap(const RegionT *R) const {
518  assert(R && "Re must be non-null");
519  for (const typename Tr::RegionNodeT *Element : R->elements()) {
520    if (Element->isSubRegion()) {
521      const RegionT *SR = Element->template getNodeAs<RegionT>();
522      verifyBBMap(SR);
523    } else {
524      BlockT *BB = Element->template getNodeAs<BlockT>();
525      if (getRegionFor(BB) != R)
526        llvm_unreachable("BB map does not match region nesting");
527    }
528  }
529}
530
531template <class Tr>
532bool RegionInfoBase<Tr>::isCommonDomFrontier(BlockT *BB, BlockT *entry,
533                                             BlockT *exit) const {
534  for (BlockT *P : make_range(InvBlockTraits::child_begin(BB),
535                              InvBlockTraits::child_end(BB))) {
536    if (DT->dominates(entry, P) && !DT->dominates(exit, P))
537      return false;
538  }
539
540  return true;
541}
542
543template <class Tr>
544bool RegionInfoBase<Tr>::isRegion(BlockT *entry, BlockT *exit) const {
545  assert(entry && exit && "entry and exit must not be null!");
546  typedef typename DomFrontierT::DomSetType DST;
547
548  DST *entrySuccs = &DF->find(entry)->second;
549
550  // Exit is the header of a loop that contains the entry. In this case,
551  // the dominance frontier must only contain the exit.
552  if (!DT->dominates(entry, exit)) {
553    for (typename DST::iterator SI = entrySuccs->begin(),
554                                SE = entrySuccs->end();
555         SI != SE; ++SI) {
556      if (*SI != exit && *SI != entry)
557        return false;
558    }
559
560    return true;
561  }
562
563  DST *exitSuccs = &DF->find(exit)->second;
564
565  // Do not allow edges leaving the region.
566  for (BlockT *Succ : *entrySuccs) {
567    if (Succ == exit || Succ == entry)
568      continue;
569    if (exitSuccs->find(Succ) == exitSuccs->end())
570      return false;
571    if (!isCommonDomFrontier(Succ, entry, exit))
572      return false;
573  }
574
575  // Do not allow edges pointing into the region.
576  for (BlockT *Succ : *exitSuccs) {
577    if (DT->properlyDominates(entry, Succ) && Succ != exit)
578      return false;
579  }
580
581  return true;
582}
583
584template <class Tr>
585void RegionInfoBase<Tr>::insertShortCut(BlockT *entry, BlockT *exit,
586                                        BBtoBBMap *ShortCut) const {
587  assert(entry && exit && "entry and exit must not be null!");
588
589  typename BBtoBBMap::iterator e = ShortCut->find(exit);
590
591  if (e == ShortCut->end())
592    // No further region at exit available.
593    (*ShortCut)[entry] = exit;
594  else {
595    // We found a region e that starts at exit. Therefore (entry, e->second)
596    // is also a region, that is larger than (entry, exit). Insert the
597    // larger one.
598    BlockT *BB = e->second;
599    (*ShortCut)[entry] = BB;
600  }
601}
602
603template <class Tr>
604typename Tr::DomTreeNodeT *
605RegionInfoBase<Tr>::getNextPostDom(DomTreeNodeT *N, BBtoBBMap *ShortCut) const {
606  typename BBtoBBMap::iterator e = ShortCut->find(N->getBlock());
607
608  if (e == ShortCut->end())
609    return N->getIDom();
610
611  return PDT->getNode(e->second)->getIDom();
612}
613
614template <class Tr>
615bool RegionInfoBase<Tr>::isTrivialRegion(BlockT *entry, BlockT *exit) const {
616  assert(entry && exit && "entry and exit must not be null!");
617
618  unsigned num_successors =
619      BlockTraits::child_end(entry) - BlockTraits::child_begin(entry);
620
621  if (num_successors <= 1 && exit == *(BlockTraits::child_begin(entry)))
622    return true;
623
624  return false;
625}
626
627template <class Tr>
628typename Tr::RegionT *RegionInfoBase<Tr>::createRegion(BlockT *entry,
629                                                       BlockT *exit) {
630  assert(entry && exit && "entry and exit must not be null!");
631
632  if (isTrivialRegion(entry, exit))
633    return nullptr;
634
635  RegionT *region =
636      new RegionT(entry, exit, static_cast<RegionInfoT *>(this), DT);
637  BBtoRegion.insert({entry, region});
638
639#ifdef EXPENSIVE_CHECKS
640  region->verifyRegion();
641#else
642  DEBUG(region->verifyRegion());
643#endif
644
645  updateStatistics(region);
646  return region;
647}
648
649template <class Tr>
650void RegionInfoBase<Tr>::findRegionsWithEntry(BlockT *entry,
651                                              BBtoBBMap *ShortCut) {
652  assert(entry);
653
654  DomTreeNodeT *N = PDT->getNode(entry);
655  if (!N)
656    return;
657
658  RegionT *lastRegion = nullptr;
659  BlockT *lastExit = entry;
660
661  // As only a BasicBlock that postdominates entry can finish a region, walk the
662  // post dominance tree upwards.
663  while ((N = getNextPostDom(N, ShortCut))) {
664    BlockT *exit = N->getBlock();
665
666    if (!exit)
667      break;
668
669    if (isRegion(entry, exit)) {
670      RegionT *newRegion = createRegion(entry, exit);
671
672      if (lastRegion)
673        newRegion->addSubRegion(lastRegion);
674
675      lastRegion = newRegion;
676      lastExit = exit;
677    }
678
679    // This can never be a region, so stop the search.
680    if (!DT->dominates(entry, exit))
681      break;
682  }
683
684  // Tried to create regions from entry to lastExit.  Next time take a
685  // shortcut from entry to lastExit.
686  if (lastExit != entry)
687    insertShortCut(entry, lastExit, ShortCut);
688}
689
690template <class Tr>
691void RegionInfoBase<Tr>::scanForRegions(FuncT &F, BBtoBBMap *ShortCut) {
692  typedef typename std::add_pointer<FuncT>::type FuncPtrT;
693  BlockT *entry = GraphTraits<FuncPtrT>::getEntryNode(&F);
694  DomTreeNodeT *N = DT->getNode(entry);
695
696  // Iterate over the dominance tree in post order to start with the small
697  // regions from the bottom of the dominance tree.  If the small regions are
698  // detected first, detection of bigger regions is faster, as we can jump
699  // over the small regions.
700  for (auto DomNode : post_order(N))
701    findRegionsWithEntry(DomNode->getBlock(), ShortCut);
702}
703
704template <class Tr>
705typename Tr::RegionT *RegionInfoBase<Tr>::getTopMostParent(RegionT *region) {
706  while (region->getParent())
707    region = region->getParent();
708
709  return region;
710}
711
712template <class Tr>
713void RegionInfoBase<Tr>::buildRegionsTree(DomTreeNodeT *N, RegionT *region) {
714  BlockT *BB = N->getBlock();
715
716  // Passed region exit
717  while (BB == region->getExit())
718    region = region->getParent();
719
720  typename BBtoRegionMap::iterator it = BBtoRegion.find(BB);
721
722  // This basic block is a start block of a region. It is already in the
723  // BBtoRegion relation. Only the child basic blocks have to be updated.
724  if (it != BBtoRegion.end()) {
725    RegionT *newRegion = it->second;
726    region->addSubRegion(getTopMostParent(newRegion));
727    region = newRegion;
728  } else {
729    BBtoRegion[BB] = region;
730  }
731
732  for (DomTreeNodeBase<BlockT> *C : *N) {
733    buildRegionsTree(C, region);
734  }
735}
736
737#ifdef EXPENSIVE_CHECKS
738template <class Tr>
739bool RegionInfoBase<Tr>::VerifyRegionInfo = true;
740#else
741template <class Tr>
742bool RegionInfoBase<Tr>::VerifyRegionInfo = false;
743#endif
744
745template <class Tr>
746typename Tr::RegionT::PrintStyle RegionInfoBase<Tr>::printStyle =
747    RegionBase<Tr>::PrintNone;
748
749template <class Tr>
750void RegionInfoBase<Tr>::print(raw_ostream &OS) const {
751  OS << "Region tree:\n";
752  TopLevelRegion->print(OS, true, 0, printStyle);
753  OS << "End region tree\n";
754}
755
756#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
757template <class Tr>
758void RegionInfoBase<Tr>::dump() const { print(dbgs()); }
759#endif
760
761template <class Tr>
762void RegionInfoBase<Tr>::releaseMemory() {
763  BBtoRegion.clear();
764  if (TopLevelRegion)
765    delete TopLevelRegion;
766  TopLevelRegion = nullptr;
767}
768
769template <class Tr>
770void RegionInfoBase<Tr>::verifyAnalysis() const {
771  // Do only verify regions if explicitely activated using EXPENSIVE_CHECKS or
772  // -verify-region-info
773  if (!RegionInfoBase<Tr>::VerifyRegionInfo)
774    return;
775
776  TopLevelRegion->verifyRegionNest();
777
778  verifyBBMap(TopLevelRegion);
779}
780
781// Region pass manager support.
782template <class Tr>
783typename Tr::RegionT *RegionInfoBase<Tr>::getRegionFor(BlockT *BB) const {
784  typename BBtoRegionMap::const_iterator I = BBtoRegion.find(BB);
785  return I != BBtoRegion.end() ? I->second : nullptr;
786}
787
788template <class Tr>
789void RegionInfoBase<Tr>::setRegionFor(BlockT *BB, RegionT *R) {
790  BBtoRegion[BB] = R;
791}
792
793template <class Tr>
794typename Tr::RegionT *RegionInfoBase<Tr>::operator[](BlockT *BB) const {
795  return getRegionFor(BB);
796}
797
798template <class Tr>
799typename RegionInfoBase<Tr>::BlockT *
800RegionInfoBase<Tr>::getMaxRegionExit(BlockT *BB) const {
801  BlockT *Exit = nullptr;
802
803  while (true) {
804    // Get largest region that starts at BB.
805    RegionT *R = getRegionFor(BB);
806    while (R && R->getParent() && R->getParent()->getEntry() == BB)
807      R = R->getParent();
808
809    // Get the single exit of BB.
810    if (R && R->getEntry() == BB)
811      Exit = R->getExit();
812    else if (++BlockTraits::child_begin(BB) == BlockTraits::child_end(BB))
813      Exit = *BlockTraits::child_begin(BB);
814    else // No single exit exists.
815      return Exit;
816
817    // Get largest region that starts at Exit.
818    RegionT *ExitR = getRegionFor(Exit);
819    while (ExitR && ExitR->getParent() &&
820           ExitR->getParent()->getEntry() == Exit)
821      ExitR = ExitR->getParent();
822
823    for (BlockT *Pred : make_range(InvBlockTraits::child_begin(Exit),
824                                   InvBlockTraits::child_end(Exit))) {
825      if (!R->contains(Pred) && !ExitR->contains(Pred))
826        break;
827    }
828
829    // This stops infinite cycles.
830    if (DT->dominates(Exit, BB))
831      break;
832
833    BB = Exit;
834  }
835
836  return Exit;
837}
838
839template <class Tr>
840typename Tr::RegionT *RegionInfoBase<Tr>::getCommonRegion(RegionT *A,
841                                                          RegionT *B) const {
842  assert(A && B && "One of the Regions is NULL");
843
844  if (A->contains(B))
845    return A;
846
847  while (!B->contains(A))
848    B = B->getParent();
849
850  return B;
851}
852
853template <class Tr>
854typename Tr::RegionT *
855RegionInfoBase<Tr>::getCommonRegion(SmallVectorImpl<RegionT *> &Regions) const {
856  RegionT *ret = Regions.back();
857  Regions.pop_back();
858
859  for (RegionT *R : Regions)
860    ret = getCommonRegion(ret, R);
861
862  return ret;
863}
864
865template <class Tr>
866typename Tr::RegionT *
867RegionInfoBase<Tr>::getCommonRegion(SmallVectorImpl<BlockT *> &BBs) const {
868  RegionT *ret = getRegionFor(BBs.back());
869  BBs.pop_back();
870
871  for (BlockT *BB : BBs)
872    ret = getCommonRegion(ret, getRegionFor(BB));
873
874  return ret;
875}
876
877template <class Tr>
878void RegionInfoBase<Tr>::calculate(FuncT &F) {
879  typedef typename std::add_pointer<FuncT>::type FuncPtrT;
880
881  // ShortCut a function where for every BB the exit of the largest region
882  // starting with BB is stored. These regions can be threated as single BBS.
883  // This improves performance on linear CFGs.
884  BBtoBBMap ShortCut;
885
886  scanForRegions(F, &ShortCut);
887  BlockT *BB = GraphTraits<FuncPtrT>::getEntryNode(&F);
888  buildRegionsTree(DT->getNode(BB), TopLevelRegion);
889}
890
891#undef DEBUG_TYPE
892
893} // end namespace llvm
894
895#endif
896