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/CommandLine.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include <algorithm>
25 #include <iterator>
26 #include <set>
27
28 namespace llvm {
29
30 #define DEBUG_TYPE "region"
31
32 //===----------------------------------------------------------------------===//
33 /// RegionBase Implementation
34 template <class Tr>
RegionBase(BlockT * Entry,BlockT * Exit,typename Tr::RegionInfoT * RInfo,DomTreeT * dt,RegionT * Parent)35 RegionBase<Tr>::RegionBase(BlockT *Entry, BlockT *Exit,
36 typename Tr::RegionInfoT *RInfo, DomTreeT *dt,
37 RegionT *Parent)
38 : RegionNodeBase<Tr>(Parent, Entry, 1), RI(RInfo), DT(dt), exit(Exit) {}
39
40 template <class Tr>
~RegionBase()41 RegionBase<Tr>::~RegionBase() {
42 // Free the cached nodes.
43 for (typename BBNodeMapT::iterator it = BBNodeMap.begin(),
44 ie = BBNodeMap.end();
45 it != ie; ++it)
46 delete it->second;
47
48 // Only clean the cache for this Region. Caches of child Regions will be
49 // cleaned when the child Regions are deleted.
50 BBNodeMap.clear();
51 }
52
53 template <class Tr>
replaceEntry(BlockT * BB)54 void RegionBase<Tr>::replaceEntry(BlockT *BB) {
55 this->entry.setPointer(BB);
56 }
57
58 template <class Tr>
replaceExit(BlockT * BB)59 void RegionBase<Tr>::replaceExit(BlockT *BB) {
60 assert(exit && "No exit to replace!");
61 exit = BB;
62 }
63
64 template <class Tr>
replaceEntryRecursive(BlockT * NewEntry)65 void RegionBase<Tr>::replaceEntryRecursive(BlockT *NewEntry) {
66 std::vector<RegionT *> RegionQueue;
67 BlockT *OldEntry = getEntry();
68
69 RegionQueue.push_back(static_cast<RegionT *>(this));
70 while (!RegionQueue.empty()) {
71 RegionT *R = RegionQueue.back();
72 RegionQueue.pop_back();
73
74 R->replaceEntry(NewEntry);
75 for (typename RegionT::const_iterator RI = R->begin(), RE = R->end();
76 RI != RE; ++RI) {
77 if ((*RI)->getEntry() == OldEntry)
78 RegionQueue.push_back(RI->get());
79 }
80 }
81 }
82
83 template <class Tr>
replaceExitRecursive(BlockT * NewExit)84 void RegionBase<Tr>::replaceExitRecursive(BlockT *NewExit) {
85 std::vector<RegionT *> RegionQueue;
86 BlockT *OldExit = getExit();
87
88 RegionQueue.push_back(static_cast<RegionT *>(this));
89 while (!RegionQueue.empty()) {
90 RegionT *R = RegionQueue.back();
91 RegionQueue.pop_back();
92
93 R->replaceExit(NewExit);
94 for (typename RegionT::const_iterator RI = R->begin(), RE = R->end();
95 RI != RE; ++RI) {
96 if ((*RI)->getExit() == OldExit)
97 RegionQueue.push_back(RI->get());
98 }
99 }
100 }
101
102 template <class Tr>
contains(const BlockT * B)103 bool RegionBase<Tr>::contains(const BlockT *B) const {
104 BlockT *BB = const_cast<BlockT *>(B);
105
106 if (!DT->getNode(BB))
107 return false;
108
109 BlockT *entry = getEntry(), *exit = getExit();
110
111 // Toplevel region.
112 if (!exit)
113 return true;
114
115 return (DT->dominates(entry, BB) &&
116 !(DT->dominates(exit, BB) && DT->dominates(entry, exit)));
117 }
118
119 template <class Tr>
contains(const LoopT * L)120 bool RegionBase<Tr>::contains(const LoopT *L) const {
121 // BBs that are not part of any loop are element of the Loop
122 // described by the NULL pointer. This loop is not part of any region,
123 // except if the region describes the whole function.
124 if (!L)
125 return getExit() == nullptr;
126
127 if (!contains(L->getHeader()))
128 return false;
129
130 SmallVector<BlockT *, 8> ExitingBlocks;
131 L->getExitingBlocks(ExitingBlocks);
132
133 for (BlockT *BB : ExitingBlocks) {
134 if (!contains(BB))
135 return false;
136 }
137
138 return true;
139 }
140
141 template <class Tr>
outermostLoopInRegion(LoopT * L)142 typename Tr::LoopT *RegionBase<Tr>::outermostLoopInRegion(LoopT *L) const {
143 if (!contains(L))
144 return nullptr;
145
146 while (L && contains(L->getParentLoop())) {
147 L = L->getParentLoop();
148 }
149
150 return L;
151 }
152
153 template <class Tr>
outermostLoopInRegion(LoopInfoT * LI,BlockT * BB)154 typename Tr::LoopT *RegionBase<Tr>::outermostLoopInRegion(LoopInfoT *LI,
155 BlockT *BB) const {
156 assert(LI && BB && "LI and BB cannot be null!");
157 LoopT *L = LI->getLoopFor(BB);
158 return outermostLoopInRegion(L);
159 }
160
161 template <class Tr>
getEnteringBlock()162 typename RegionBase<Tr>::BlockT *RegionBase<Tr>::getEnteringBlock() const {
163 BlockT *entry = getEntry();
164 BlockT *Pred;
165 BlockT *enteringBlock = nullptr;
166
167 for (PredIterTy PI = InvBlockTraits::child_begin(entry),
168 PE = InvBlockTraits::child_end(entry);
169 PI != PE; ++PI) {
170 Pred = *PI;
171 if (DT->getNode(Pred) && !contains(Pred)) {
172 if (enteringBlock)
173 return nullptr;
174
175 enteringBlock = Pred;
176 }
177 }
178
179 return enteringBlock;
180 }
181
182 template <class Tr>
getExitingBlock()183 typename RegionBase<Tr>::BlockT *RegionBase<Tr>::getExitingBlock() const {
184 BlockT *exit = getExit();
185 BlockT *Pred;
186 BlockT *exitingBlock = nullptr;
187
188 if (!exit)
189 return nullptr;
190
191 for (PredIterTy PI = InvBlockTraits::child_begin(exit),
192 PE = InvBlockTraits::child_end(exit);
193 PI != PE; ++PI) {
194 Pred = *PI;
195 if (contains(Pred)) {
196 if (exitingBlock)
197 return nullptr;
198
199 exitingBlock = Pred;
200 }
201 }
202
203 return exitingBlock;
204 }
205
206 template <class Tr>
isSimple()207 bool RegionBase<Tr>::isSimple() const {
208 return !isTopLevelRegion() && getEnteringBlock() && getExitingBlock();
209 }
210
211 template <class Tr>
getNameStr()212 std::string RegionBase<Tr>::getNameStr() const {
213 std::string exitName;
214 std::string entryName;
215
216 if (getEntry()->getName().empty()) {
217 raw_string_ostream OS(entryName);
218
219 getEntry()->printAsOperand(OS, false);
220 } else
221 entryName = getEntry()->getName();
222
223 if (getExit()) {
224 if (getExit()->getName().empty()) {
225 raw_string_ostream OS(exitName);
226
227 getExit()->printAsOperand(OS, false);
228 } else
229 exitName = getExit()->getName();
230 } else
231 exitName = "<Function Return>";
232
233 return entryName + " => " + exitName;
234 }
235
236 template <class Tr>
verifyBBInRegion(BlockT * BB)237 void RegionBase<Tr>::verifyBBInRegion(BlockT *BB) const {
238 if (!contains(BB))
239 llvm_unreachable("Broken region found: enumerated BB not in region!");
240
241 BlockT *entry = getEntry(), *exit = getExit();
242
243 for (SuccIterTy SI = BlockTraits::child_begin(BB),
244 SE = BlockTraits::child_end(BB);
245 SI != SE; ++SI) {
246 if (!contains(*SI) && exit != *SI)
247 llvm_unreachable("Broken region found: edges leaving the region must go "
248 "to the exit node!");
249 }
250
251 if (entry != BB) {
252 for (PredIterTy SI = InvBlockTraits::child_begin(BB),
253 SE = InvBlockTraits::child_end(BB);
254 SI != SE; ++SI) {
255 if (!contains(*SI))
256 llvm_unreachable("Broken region found: edges entering the region must "
257 "go to the entry node!");
258 }
259 }
260 }
261
262 template <class Tr>
verifyWalk(BlockT * BB,std::set<BlockT * > * visited)263 void RegionBase<Tr>::verifyWalk(BlockT *BB, std::set<BlockT *> *visited) const {
264 BlockT *exit = getExit();
265
266 visited->insert(BB);
267
268 verifyBBInRegion(BB);
269
270 for (SuccIterTy SI = BlockTraits::child_begin(BB),
271 SE = BlockTraits::child_end(BB);
272 SI != SE; ++SI) {
273 if (*SI != exit && visited->find(*SI) == visited->end())
274 verifyWalk(*SI, visited);
275 }
276 }
277
278 template <class Tr>
verifyRegion()279 void RegionBase<Tr>::verifyRegion() const {
280 // Only do verification when user wants to, otherwise this expensive check
281 // will be invoked by PMDataManager::verifyPreservedAnalysis when
282 // a regionpass (marked PreservedAll) finish.
283 if (!RegionInfoBase<Tr>::VerifyRegionInfo)
284 return;
285
286 std::set<BlockT *> visited;
287 verifyWalk(getEntry(), &visited);
288 }
289
290 template <class Tr>
verifyRegionNest()291 void RegionBase<Tr>::verifyRegionNest() const {
292 for (typename RegionT::const_iterator RI = begin(), RE = end(); RI != RE;
293 ++RI)
294 (*RI)->verifyRegionNest();
295
296 verifyRegion();
297 }
298
299 template <class Tr>
element_begin()300 typename RegionBase<Tr>::element_iterator RegionBase<Tr>::element_begin() {
301 return GraphTraits<RegionT *>::nodes_begin(static_cast<RegionT *>(this));
302 }
303
304 template <class Tr>
element_end()305 typename RegionBase<Tr>::element_iterator RegionBase<Tr>::element_end() {
306 return GraphTraits<RegionT *>::nodes_end(static_cast<RegionT *>(this));
307 }
308
309 template <class Tr>
310 typename RegionBase<Tr>::const_element_iterator
element_begin()311 RegionBase<Tr>::element_begin() const {
312 return GraphTraits<const RegionT *>::nodes_begin(
313 static_cast<const RegionT *>(this));
314 }
315
316 template <class Tr>
317 typename RegionBase<Tr>::const_element_iterator
element_end()318 RegionBase<Tr>::element_end() const {
319 return GraphTraits<const RegionT *>::nodes_end(
320 static_cast<const RegionT *>(this));
321 }
322
323 template <class Tr>
getSubRegionNode(BlockT * BB)324 typename Tr::RegionT *RegionBase<Tr>::getSubRegionNode(BlockT *BB) const {
325 typedef typename Tr::RegionT RegionT;
326 RegionT *R = RI->getRegionFor(BB);
327
328 if (!R || R == this)
329 return nullptr;
330
331 // If we pass the BB out of this region, that means our code is broken.
332 assert(contains(R) && "BB not in current region!");
333
334 while (contains(R->getParent()) && R->getParent() != this)
335 R = R->getParent();
336
337 if (R->getEntry() != BB)
338 return nullptr;
339
340 return R;
341 }
342
343 template <class Tr>
getBBNode(BlockT * BB)344 typename Tr::RegionNodeT *RegionBase<Tr>::getBBNode(BlockT *BB) const {
345 assert(contains(BB) && "Can get BB node out of this region!");
346
347 typename BBNodeMapT::const_iterator at = BBNodeMap.find(BB);
348
349 if (at != BBNodeMap.end())
350 return at->second;
351
352 auto Deconst = const_cast<RegionBase<Tr> *>(this);
353 RegionNodeT *NewNode = new RegionNodeT(static_cast<RegionT *>(Deconst), BB);
354 BBNodeMap.insert(std::make_pair(BB, NewNode));
355 return NewNode;
356 }
357
358 template <class Tr>
getNode(BlockT * BB)359 typename Tr::RegionNodeT *RegionBase<Tr>::getNode(BlockT *BB) const {
360 assert(contains(BB) && "Can get BB node out of this region!");
361 if (RegionT *Child = getSubRegionNode(BB))
362 return Child->getNode();
363
364 return getBBNode(BB);
365 }
366
367 template <class Tr>
transferChildrenTo(RegionT * To)368 void RegionBase<Tr>::transferChildrenTo(RegionT *To) {
369 for (iterator I = begin(), E = end(); I != E; ++I) {
370 (*I)->parent = To;
371 To->children.push_back(std::move(*I));
372 }
373 children.clear();
374 }
375
376 template <class Tr>
addSubRegion(RegionT * SubRegion,bool moveChildren)377 void RegionBase<Tr>::addSubRegion(RegionT *SubRegion, bool moveChildren) {
378 assert(!SubRegion->parent && "SubRegion already has a parent!");
379 assert(std::find_if(begin(), end(), [&](const std::unique_ptr<RegionT> &R) {
380 return R.get() == SubRegion;
381 }) == children.end() &&
382 "Subregion already exists!");
383
384 SubRegion->parent = static_cast<RegionT *>(this);
385 children.push_back(std::unique_ptr<RegionT>(SubRegion));
386
387 if (!moveChildren)
388 return;
389
390 assert(SubRegion->children.empty() &&
391 "SubRegions that contain children are not supported");
392
393 for (element_iterator I = element_begin(), E = element_end(); I != E; ++I) {
394 if (!(*I)->isSubRegion()) {
395 BlockT *BB = (*I)->template getNodeAs<BlockT>();
396
397 if (SubRegion->contains(BB))
398 RI->setRegionFor(BB, SubRegion);
399 }
400 }
401
402 std::vector<std::unique_ptr<RegionT>> Keep;
403 for (iterator I = begin(), E = end(); I != E; ++I) {
404 if (SubRegion->contains(I->get()) && I->get() != SubRegion) {
405 (*I)->parent = SubRegion;
406 SubRegion->children.push_back(std::move(*I));
407 } else
408 Keep.push_back(std::move(*I));
409 }
410
411 children.clear();
412 children.insert(
413 children.begin(),
414 std::move_iterator<typename RegionSet::iterator>(Keep.begin()),
415 std::move_iterator<typename RegionSet::iterator>(Keep.end()));
416 }
417
418 template <class Tr>
removeSubRegion(RegionT * Child)419 typename Tr::RegionT *RegionBase<Tr>::removeSubRegion(RegionT *Child) {
420 assert(Child->parent == this && "Child is not a child of this region!");
421 Child->parent = nullptr;
422 typename RegionSet::iterator I = std::find_if(
423 children.begin(), children.end(),
424 [&](const std::unique_ptr<RegionT> &R) { return R.get() == Child; });
425 assert(I != children.end() && "Region does not exit. Unable to remove.");
426 children.erase(children.begin() + (I - begin()));
427 return Child;
428 }
429
430 template <class Tr>
getDepth()431 unsigned RegionBase<Tr>::getDepth() const {
432 unsigned Depth = 0;
433
434 for (RegionT *R = getParent(); R != nullptr; R = R->getParent())
435 ++Depth;
436
437 return Depth;
438 }
439
440 template <class Tr>
getExpandedRegion()441 typename Tr::RegionT *RegionBase<Tr>::getExpandedRegion() const {
442 unsigned NumSuccessors = Tr::getNumSuccessors(exit);
443
444 if (NumSuccessors == 0)
445 return nullptr;
446
447 RegionT *R = RI->getRegionFor(exit);
448
449 if (R->getEntry() != exit) {
450 for (PredIterTy PI = InvBlockTraits::child_begin(getExit()),
451 PE = InvBlockTraits::child_end(getExit());
452 PI != PE; ++PI)
453 if (!contains(*PI))
454 return nullptr;
455 if (Tr::getNumSuccessors(exit) == 1)
456 return new RegionT(getEntry(), *BlockTraits::child_begin(exit), RI, DT);
457 return nullptr;
458 }
459
460 while (R->getParent() && R->getParent()->getEntry() == exit)
461 R = R->getParent();
462
463 for (PredIterTy PI = InvBlockTraits::child_begin(getExit()),
464 PE = InvBlockTraits::child_end(getExit());
465 PI != PE; ++PI) {
466 if (!(contains(*PI) || R->contains(*PI)))
467 return nullptr;
468 }
469
470 return new RegionT(getEntry(), R->getExit(), RI, DT);
471 }
472
473 template <class Tr>
print(raw_ostream & OS,bool print_tree,unsigned level,PrintStyle Style)474 void RegionBase<Tr>::print(raw_ostream &OS, bool print_tree, unsigned level,
475 PrintStyle Style) const {
476 if (print_tree)
477 OS.indent(level * 2) << '[' << level << "] " << getNameStr();
478 else
479 OS.indent(level * 2) << getNameStr();
480
481 OS << '\n';
482
483 if (Style != PrintNone) {
484 OS.indent(level * 2) << "{\n";
485 OS.indent(level * 2 + 2);
486
487 if (Style == PrintBB) {
488 for (const auto *BB : blocks())
489 OS << BB->getName() << ", "; // TODO: remove the last ","
490 } else if (Style == PrintRN) {
491 for (const_element_iterator I = element_begin(), E = element_end();
492 I != E; ++I) {
493 OS << **I << ", "; // TODO: remove the last ",
494 }
495 }
496
497 OS << '\n';
498 }
499
500 if (print_tree) {
501 for (const_iterator RI = begin(), RE = end(); RI != RE; ++RI)
502 (*RI)->print(OS, print_tree, level + 1, Style);
503 }
504
505 if (Style != PrintNone)
506 OS.indent(level * 2) << "} \n";
507 }
508
509 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
510 template <class Tr>
dump()511 void RegionBase<Tr>::dump() const {
512 print(dbgs(), true, getDepth(), RegionInfoBase<Tr>::printStyle);
513 }
514 #endif
515
516 template <class Tr>
clearNodeCache()517 void RegionBase<Tr>::clearNodeCache() {
518 // Free the cached nodes.
519 for (typename BBNodeMapT::iterator I = BBNodeMap.begin(),
520 IE = BBNodeMap.end();
521 I != IE; ++I)
522 delete I->second;
523
524 BBNodeMap.clear();
525 for (typename RegionT::iterator RI = begin(), RE = end(); RI != RE; ++RI)
526 (*RI)->clearNodeCache();
527 }
528
529 //===----------------------------------------------------------------------===//
530 // RegionInfoBase implementation
531 //
532
533 template <class Tr>
RegionInfoBase()534 RegionInfoBase<Tr>::RegionInfoBase()
535 : TopLevelRegion(nullptr) {}
536
537 template <class Tr>
~RegionInfoBase()538 RegionInfoBase<Tr>::~RegionInfoBase() {
539 releaseMemory();
540 }
541
542 template <class Tr>
verifyBBMap(const RegionT * R)543 void RegionInfoBase<Tr>::verifyBBMap(const RegionT *R) const {
544 assert(R && "Re must be non-null");
545 for (auto I = R->element_begin(), E = R->element_end(); I != E; ++I) {
546 if (I->isSubRegion()) {
547 const RegionT *SR = I->template getNodeAs<RegionT>();
548 verifyBBMap(SR);
549 } else {
550 BlockT *BB = I->template getNodeAs<BlockT>();
551 if (getRegionFor(BB) != R)
552 llvm_unreachable("BB map does not match region nesting");
553 }
554 }
555 }
556
557 template <class Tr>
isCommonDomFrontier(BlockT * BB,BlockT * entry,BlockT * exit)558 bool RegionInfoBase<Tr>::isCommonDomFrontier(BlockT *BB, BlockT *entry,
559 BlockT *exit) const {
560 for (PredIterTy PI = InvBlockTraits::child_begin(BB),
561 PE = InvBlockTraits::child_end(BB);
562 PI != PE; ++PI) {
563 BlockT *P = *PI;
564 if (DT->dominates(entry, P) && !DT->dominates(exit, P))
565 return false;
566 }
567
568 return true;
569 }
570
571 template <class Tr>
isRegion(BlockT * entry,BlockT * exit)572 bool RegionInfoBase<Tr>::isRegion(BlockT *entry, BlockT *exit) const {
573 assert(entry && exit && "entry and exit must not be null!");
574 typedef typename DomFrontierT::DomSetType DST;
575
576 DST *entrySuccs = &DF->find(entry)->second;
577
578 // Exit is the header of a loop that contains the entry. In this case,
579 // the dominance frontier must only contain the exit.
580 if (!DT->dominates(entry, exit)) {
581 for (typename DST::iterator SI = entrySuccs->begin(),
582 SE = entrySuccs->end();
583 SI != SE; ++SI) {
584 if (*SI != exit && *SI != entry)
585 return false;
586 }
587
588 return true;
589 }
590
591 DST *exitSuccs = &DF->find(exit)->second;
592
593 // Do not allow edges leaving the region.
594 for (typename DST::iterator SI = entrySuccs->begin(), SE = entrySuccs->end();
595 SI != SE; ++SI) {
596 if (*SI == exit || *SI == entry)
597 continue;
598 if (exitSuccs->find(*SI) == exitSuccs->end())
599 return false;
600 if (!isCommonDomFrontier(*SI, entry, exit))
601 return false;
602 }
603
604 // Do not allow edges pointing into the region.
605 for (typename DST::iterator SI = exitSuccs->begin(), SE = exitSuccs->end();
606 SI != SE; ++SI) {
607 if (DT->properlyDominates(entry, *SI) && *SI != exit)
608 return false;
609 }
610
611 return true;
612 }
613
614 template <class Tr>
insertShortCut(BlockT * entry,BlockT * exit,BBtoBBMap * ShortCut)615 void RegionInfoBase<Tr>::insertShortCut(BlockT *entry, BlockT *exit,
616 BBtoBBMap *ShortCut) const {
617 assert(entry && exit && "entry and exit must not be null!");
618
619 typename BBtoBBMap::iterator e = ShortCut->find(exit);
620
621 if (e == ShortCut->end())
622 // No further region at exit available.
623 (*ShortCut)[entry] = exit;
624 else {
625 // We found a region e that starts at exit. Therefore (entry, e->second)
626 // is also a region, that is larger than (entry, exit). Insert the
627 // larger one.
628 BlockT *BB = e->second;
629 (*ShortCut)[entry] = BB;
630 }
631 }
632
633 template <class Tr>
634 typename Tr::DomTreeNodeT *
getNextPostDom(DomTreeNodeT * N,BBtoBBMap * ShortCut)635 RegionInfoBase<Tr>::getNextPostDom(DomTreeNodeT *N, BBtoBBMap *ShortCut) const {
636 typename BBtoBBMap::iterator e = ShortCut->find(N->getBlock());
637
638 if (e == ShortCut->end())
639 return N->getIDom();
640
641 return PDT->getNode(e->second)->getIDom();
642 }
643
644 template <class Tr>
isTrivialRegion(BlockT * entry,BlockT * exit)645 bool RegionInfoBase<Tr>::isTrivialRegion(BlockT *entry, BlockT *exit) const {
646 assert(entry && exit && "entry and exit must not be null!");
647
648 unsigned num_successors =
649 BlockTraits::child_end(entry) - BlockTraits::child_begin(entry);
650
651 if (num_successors <= 1 && exit == *(BlockTraits::child_begin(entry)))
652 return true;
653
654 return false;
655 }
656
657 template <class Tr>
createRegion(BlockT * entry,BlockT * exit)658 typename Tr::RegionT *RegionInfoBase<Tr>::createRegion(BlockT *entry,
659 BlockT *exit) {
660 assert(entry && exit && "entry and exit must not be null!");
661
662 if (isTrivialRegion(entry, exit))
663 return nullptr;
664
665 RegionT *region =
666 new RegionT(entry, exit, static_cast<RegionInfoT *>(this), DT);
667 BBtoRegion.insert(std::make_pair(entry, region));
668
669 #ifdef XDEBUG
670 region->verifyRegion();
671 #else
672 DEBUG(region->verifyRegion());
673 #endif
674
675 updateStatistics(region);
676 return region;
677 }
678
679 template <class Tr>
findRegionsWithEntry(BlockT * entry,BBtoBBMap * ShortCut)680 void RegionInfoBase<Tr>::findRegionsWithEntry(BlockT *entry,
681 BBtoBBMap *ShortCut) {
682 assert(entry);
683
684 DomTreeNodeT *N = PDT->getNode(entry);
685 if (!N)
686 return;
687
688 RegionT *lastRegion = nullptr;
689 BlockT *lastExit = entry;
690
691 // As only a BasicBlock that postdominates entry can finish a region, walk the
692 // post dominance tree upwards.
693 while ((N = getNextPostDom(N, ShortCut))) {
694 BlockT *exit = N->getBlock();
695
696 if (!exit)
697 break;
698
699 if (isRegion(entry, exit)) {
700 RegionT *newRegion = createRegion(entry, exit);
701
702 if (lastRegion)
703 newRegion->addSubRegion(lastRegion);
704
705 lastRegion = newRegion;
706 lastExit = exit;
707 }
708
709 // This can never be a region, so stop the search.
710 if (!DT->dominates(entry, exit))
711 break;
712 }
713
714 // Tried to create regions from entry to lastExit. Next time take a
715 // shortcut from entry to lastExit.
716 if (lastExit != entry)
717 insertShortCut(entry, lastExit, ShortCut);
718 }
719
720 template <class Tr>
scanForRegions(FuncT & F,BBtoBBMap * ShortCut)721 void RegionInfoBase<Tr>::scanForRegions(FuncT &F, BBtoBBMap *ShortCut) {
722 typedef typename std::add_pointer<FuncT>::type FuncPtrT;
723 BlockT *entry = GraphTraits<FuncPtrT>::getEntryNode(&F);
724 DomTreeNodeT *N = DT->getNode(entry);
725
726 // Iterate over the dominance tree in post order to start with the small
727 // regions from the bottom of the dominance tree. If the small regions are
728 // detected first, detection of bigger regions is faster, as we can jump
729 // over the small regions.
730 for (auto DomNode : post_order(N))
731 findRegionsWithEntry(DomNode->getBlock(), ShortCut);
732 }
733
734 template <class Tr>
getTopMostParent(RegionT * region)735 typename Tr::RegionT *RegionInfoBase<Tr>::getTopMostParent(RegionT *region) {
736 while (region->getParent())
737 region = region->getParent();
738
739 return region;
740 }
741
742 template <class Tr>
buildRegionsTree(DomTreeNodeT * N,RegionT * region)743 void RegionInfoBase<Tr>::buildRegionsTree(DomTreeNodeT *N, RegionT *region) {
744 BlockT *BB = N->getBlock();
745
746 // Passed region exit
747 while (BB == region->getExit())
748 region = region->getParent();
749
750 typename BBtoRegionMap::iterator it = BBtoRegion.find(BB);
751
752 // This basic block is a start block of a region. It is already in the
753 // BBtoRegion relation. Only the child basic blocks have to be updated.
754 if (it != BBtoRegion.end()) {
755 RegionT *newRegion = it->second;
756 region->addSubRegion(getTopMostParent(newRegion));
757 region = newRegion;
758 } else {
759 BBtoRegion[BB] = region;
760 }
761
762 for (typename DomTreeNodeT::iterator CI = N->begin(), CE = N->end(); CI != CE;
763 ++CI) {
764 buildRegionsTree(*CI, region);
765 }
766 }
767
768 #ifdef XDEBUG
769 template <class Tr>
770 bool RegionInfoBase<Tr>::VerifyRegionInfo = true;
771 #else
772 template <class Tr>
773 bool RegionInfoBase<Tr>::VerifyRegionInfo = false;
774 #endif
775
776 template <class Tr>
777 typename Tr::RegionT::PrintStyle RegionInfoBase<Tr>::printStyle =
778 RegionBase<Tr>::PrintNone;
779
780 template <class Tr>
print(raw_ostream & OS)781 void RegionInfoBase<Tr>::print(raw_ostream &OS) const {
782 OS << "Region tree:\n";
783 TopLevelRegion->print(OS, true, 0, printStyle);
784 OS << "End region tree\n";
785 }
786
787 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
788 template <class Tr>
dump()789 void RegionInfoBase<Tr>::dump() const { print(dbgs()); }
790 #endif
791
792 template <class Tr>
releaseMemory()793 void RegionInfoBase<Tr>::releaseMemory() {
794 BBtoRegion.clear();
795 if (TopLevelRegion)
796 delete TopLevelRegion;
797 TopLevelRegion = nullptr;
798 }
799
800 template <class Tr>
verifyAnalysis()801 void RegionInfoBase<Tr>::verifyAnalysis() const {
802 // Do only verify regions if explicitely activated using XDEBUG or
803 // -verify-region-info
804 if (!RegionInfoBase<Tr>::VerifyRegionInfo)
805 return;
806
807 TopLevelRegion->verifyRegionNest();
808
809 verifyBBMap(TopLevelRegion);
810 }
811
812 // Region pass manager support.
813 template <class Tr>
getRegionFor(BlockT * BB)814 typename Tr::RegionT *RegionInfoBase<Tr>::getRegionFor(BlockT *BB) const {
815 typename BBtoRegionMap::const_iterator I = BBtoRegion.find(BB);
816 return I != BBtoRegion.end() ? I->second : nullptr;
817 }
818
819 template <class Tr>
setRegionFor(BlockT * BB,RegionT * R)820 void RegionInfoBase<Tr>::setRegionFor(BlockT *BB, RegionT *R) {
821 BBtoRegion[BB] = R;
822 }
823
824 template <class Tr>
825 typename Tr::RegionT *RegionInfoBase<Tr>::operator[](BlockT *BB) const {
826 return getRegionFor(BB);
827 }
828
829 template <class Tr>
830 typename RegionInfoBase<Tr>::BlockT *
getMaxRegionExit(BlockT * BB)831 RegionInfoBase<Tr>::getMaxRegionExit(BlockT *BB) const {
832 BlockT *Exit = nullptr;
833
834 while (true) {
835 // Get largest region that starts at BB.
836 RegionT *R = getRegionFor(BB);
837 while (R && R->getParent() && R->getParent()->getEntry() == BB)
838 R = R->getParent();
839
840 // Get the single exit of BB.
841 if (R && R->getEntry() == BB)
842 Exit = R->getExit();
843 else if (++BlockTraits::child_begin(BB) == BlockTraits::child_end(BB))
844 Exit = *BlockTraits::child_begin(BB);
845 else // No single exit exists.
846 return Exit;
847
848 // Get largest region that starts at Exit.
849 RegionT *ExitR = getRegionFor(Exit);
850 while (ExitR && ExitR->getParent() &&
851 ExitR->getParent()->getEntry() == Exit)
852 ExitR = ExitR->getParent();
853
854 for (PredIterTy PI = InvBlockTraits::child_begin(Exit),
855 PE = InvBlockTraits::child_end(Exit);
856 PI != PE; ++PI) {
857 if (!R->contains(*PI) && !ExitR->contains(*PI))
858 break;
859 }
860
861 // This stops infinite cycles.
862 if (DT->dominates(Exit, BB))
863 break;
864
865 BB = Exit;
866 }
867
868 return Exit;
869 }
870
871 template <class Tr>
getCommonRegion(RegionT * A,RegionT * B)872 typename Tr::RegionT *RegionInfoBase<Tr>::getCommonRegion(RegionT *A,
873 RegionT *B) const {
874 assert(A && B && "One of the Regions is NULL");
875
876 if (A->contains(B))
877 return A;
878
879 while (!B->contains(A))
880 B = B->getParent();
881
882 return B;
883 }
884
885 template <class Tr>
886 typename Tr::RegionT *
getCommonRegion(SmallVectorImpl<RegionT * > & Regions)887 RegionInfoBase<Tr>::getCommonRegion(SmallVectorImpl<RegionT *> &Regions) const {
888 RegionT *ret = Regions.back();
889 Regions.pop_back();
890
891 for (RegionT *R : Regions)
892 ret = getCommonRegion(ret, R);
893
894 return ret;
895 }
896
897 template <class Tr>
898 typename Tr::RegionT *
getCommonRegion(SmallVectorImpl<BlockT * > & BBs)899 RegionInfoBase<Tr>::getCommonRegion(SmallVectorImpl<BlockT *> &BBs) const {
900 RegionT *ret = getRegionFor(BBs.back());
901 BBs.pop_back();
902
903 for (BlockT *BB : BBs)
904 ret = getCommonRegion(ret, getRegionFor(BB));
905
906 return ret;
907 }
908
909 template <class Tr>
calculate(FuncT & F)910 void RegionInfoBase<Tr>::calculate(FuncT &F) {
911 typedef typename std::add_pointer<FuncT>::type FuncPtrT;
912
913 // ShortCut a function where for every BB the exit of the largest region
914 // starting with BB is stored. These regions can be threated as single BBS.
915 // This improves performance on linear CFGs.
916 BBtoBBMap ShortCut;
917
918 scanForRegions(F, &ShortCut);
919 BlockT *BB = GraphTraits<FuncPtrT>::getEntryNode(&F);
920 buildRegionsTree(DT->getNode(BB), TopLevelRegion);
921 }
922
923 #undef DEBUG_TYPE
924
925 } // end namespace llvm
926
927 #endif
928