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!");
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!");
248 }
249
250 if (entry != BB) {
251 for (PredIterTy SI = InvBlockTraits::child_begin(BB),
252 SE = InvBlockTraits::child_end(BB);
253 SI != SE; ++SI) {
254 if (!contains(*SI))
255 llvm_unreachable("Broken region found!");
256 }
257 }
258 }
259
260 template <class Tr>
verifyWalk(BlockT * BB,std::set<BlockT * > * visited)261 void RegionBase<Tr>::verifyWalk(BlockT *BB, std::set<BlockT *> *visited) const {
262 BlockT *exit = getExit();
263
264 visited->insert(BB);
265
266 verifyBBInRegion(BB);
267
268 for (SuccIterTy SI = BlockTraits::child_begin(BB),
269 SE = BlockTraits::child_end(BB);
270 SI != SE; ++SI) {
271 if (*SI != exit && visited->find(*SI) == visited->end())
272 verifyWalk(*SI, visited);
273 }
274 }
275
276 template <class Tr>
verifyRegion()277 void RegionBase<Tr>::verifyRegion() const {
278 // Only do verification when user wants to, otherwise this expensive check
279 // will be invoked by PMDataManager::verifyPreservedAnalysis when
280 // a regionpass (marked PreservedAll) finish.
281 if (!RegionInfoBase<Tr>::VerifyRegionInfo)
282 return;
283
284 std::set<BlockT *> visited;
285 verifyWalk(getEntry(), &visited);
286 }
287
288 template <class Tr>
verifyRegionNest()289 void RegionBase<Tr>::verifyRegionNest() const {
290 for (typename RegionT::const_iterator RI = begin(), RE = end(); RI != RE;
291 ++RI)
292 (*RI)->verifyRegionNest();
293
294 verifyRegion();
295 }
296
297 template <class Tr>
element_begin()298 typename RegionBase<Tr>::element_iterator RegionBase<Tr>::element_begin() {
299 return GraphTraits<RegionT *>::nodes_begin(static_cast<RegionT *>(this));
300 }
301
302 template <class Tr>
element_end()303 typename RegionBase<Tr>::element_iterator RegionBase<Tr>::element_end() {
304 return GraphTraits<RegionT *>::nodes_end(static_cast<RegionT *>(this));
305 }
306
307 template <class Tr>
308 typename RegionBase<Tr>::const_element_iterator
element_begin()309 RegionBase<Tr>::element_begin() const {
310 return GraphTraits<const RegionT *>::nodes_begin(
311 static_cast<const RegionT *>(this));
312 }
313
314 template <class Tr>
315 typename RegionBase<Tr>::const_element_iterator
element_end()316 RegionBase<Tr>::element_end() const {
317 return GraphTraits<const RegionT *>::nodes_end(
318 static_cast<const RegionT *>(this));
319 }
320
321 template <class Tr>
getSubRegionNode(BlockT * BB)322 typename Tr::RegionT *RegionBase<Tr>::getSubRegionNode(BlockT *BB) const {
323 typedef typename Tr::RegionT RegionT;
324 RegionT *R = RI->getRegionFor(BB);
325
326 if (!R || R == this)
327 return nullptr;
328
329 // If we pass the BB out of this region, that means our code is broken.
330 assert(contains(R) && "BB not in current region!");
331
332 while (contains(R->getParent()) && R->getParent() != this)
333 R = R->getParent();
334
335 if (R->getEntry() != BB)
336 return nullptr;
337
338 return R;
339 }
340
341 template <class Tr>
getBBNode(BlockT * BB)342 typename Tr::RegionNodeT *RegionBase<Tr>::getBBNode(BlockT *BB) const {
343 assert(contains(BB) && "Can get BB node out of this region!");
344
345 typename BBNodeMapT::const_iterator at = BBNodeMap.find(BB);
346
347 if (at != BBNodeMap.end())
348 return at->second;
349
350 auto Deconst = const_cast<RegionBase<Tr> *>(this);
351 RegionNodeT *NewNode = new RegionNodeT(static_cast<RegionT *>(Deconst), BB);
352 BBNodeMap.insert(std::make_pair(BB, NewNode));
353 return NewNode;
354 }
355
356 template <class Tr>
getNode(BlockT * BB)357 typename Tr::RegionNodeT *RegionBase<Tr>::getNode(BlockT *BB) const {
358 assert(contains(BB) && "Can get BB node out of this region!");
359 if (RegionT *Child = getSubRegionNode(BB))
360 return Child->getNode();
361
362 return getBBNode(BB);
363 }
364
365 template <class Tr>
transferChildrenTo(RegionT * To)366 void RegionBase<Tr>::transferChildrenTo(RegionT *To) {
367 for (iterator I = begin(), E = end(); I != E; ++I) {
368 (*I)->parent = To;
369 To->children.push_back(std::move(*I));
370 }
371 children.clear();
372 }
373
374 template <class Tr>
addSubRegion(RegionT * SubRegion,bool moveChildren)375 void RegionBase<Tr>::addSubRegion(RegionT *SubRegion, bool moveChildren) {
376 assert(!SubRegion->parent && "SubRegion already has a parent!");
377 assert(std::find_if(begin(), end(), [&](const std::unique_ptr<RegionT> &R) {
378 return R.get() == SubRegion;
379 }) == children.end() &&
380 "Subregion already exists!");
381
382 SubRegion->parent = static_cast<RegionT *>(this);
383 children.push_back(std::unique_ptr<RegionT>(SubRegion));
384
385 if (!moveChildren)
386 return;
387
388 assert(SubRegion->children.empty() &&
389 "SubRegions that contain children are not supported");
390
391 for (element_iterator I = element_begin(), E = element_end(); I != E; ++I) {
392 if (!(*I)->isSubRegion()) {
393 BlockT *BB = (*I)->template getNodeAs<BlockT>();
394
395 if (SubRegion->contains(BB))
396 RI->setRegionFor(BB, SubRegion);
397 }
398 }
399
400 std::vector<std::unique_ptr<RegionT>> Keep;
401 for (iterator I = begin(), E = end(); I != E; ++I) {
402 if (SubRegion->contains(I->get()) && I->get() != SubRegion) {
403 (*I)->parent = SubRegion;
404 SubRegion->children.push_back(std::move(*I));
405 } else
406 Keep.push_back(std::move(*I));
407 }
408
409 children.clear();
410 children.insert(
411 children.begin(),
412 std::move_iterator<typename RegionSet::iterator>(Keep.begin()),
413 std::move_iterator<typename RegionSet::iterator>(Keep.end()));
414 }
415
416 template <class Tr>
removeSubRegion(RegionT * Child)417 typename Tr::RegionT *RegionBase<Tr>::removeSubRegion(RegionT *Child) {
418 assert(Child->parent == this && "Child is not a child of this region!");
419 Child->parent = nullptr;
420 typename RegionSet::iterator I = std::find_if(
421 children.begin(), children.end(),
422 [&](const std::unique_ptr<RegionT> &R) { return R.get() == Child; });
423 assert(I != children.end() && "Region does not exit. Unable to remove.");
424 children.erase(children.begin() + (I - begin()));
425 return Child;
426 }
427
428 template <class Tr>
getDepth()429 unsigned RegionBase<Tr>::getDepth() const {
430 unsigned Depth = 0;
431
432 for (RegionT *R = getParent(); R != nullptr; R = R->getParent())
433 ++Depth;
434
435 return Depth;
436 }
437
438 template <class Tr>
getExpandedRegion()439 typename Tr::RegionT *RegionBase<Tr>::getExpandedRegion() const {
440 unsigned NumSuccessors = Tr::getNumSuccessors(exit);
441
442 if (NumSuccessors == 0)
443 return nullptr;
444
445 for (PredIterTy PI = InvBlockTraits::child_begin(getExit()),
446 PE = InvBlockTraits::child_end(getExit());
447 PI != PE; ++PI) {
448 if (!DT->dominates(getEntry(), *PI))
449 return nullptr;
450 }
451
452 RegionT *R = RI->getRegionFor(exit);
453
454 if (R->getEntry() != exit) {
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 if (!DT->dominates(getEntry(), R->getExit())) {
464 for (PredIterTy PI = InvBlockTraits::child_begin(getExit()),
465 PE = InvBlockTraits::child_end(getExit());
466 PI != PE; ++PI) {
467 if (!DT->dominates(R->getExit(), *PI))
468 return nullptr;
469 }
470 }
471
472 return new RegionT(getEntry(), R->getExit(), RI, DT);
473 }
474
475 template <class Tr>
print(raw_ostream & OS,bool print_tree,unsigned level,PrintStyle Style)476 void RegionBase<Tr>::print(raw_ostream &OS, bool print_tree, unsigned level,
477 PrintStyle Style) const {
478 if (print_tree)
479 OS.indent(level * 2) << '[' << level << "] " << getNameStr();
480 else
481 OS.indent(level * 2) << getNameStr();
482
483 OS << '\n';
484
485 if (Style != PrintNone) {
486 OS.indent(level * 2) << "{\n";
487 OS.indent(level * 2 + 2);
488
489 if (Style == PrintBB) {
490 for (const auto *BB : blocks())
491 OS << BB->getName() << ", "; // TODO: remove the last ","
492 } else if (Style == PrintRN) {
493 for (const_element_iterator I = element_begin(), E = element_end();
494 I != E; ++I) {
495 OS << **I << ", "; // TODO: remove the last ",
496 }
497 }
498
499 OS << '\n';
500 }
501
502 if (print_tree) {
503 for (const_iterator RI = begin(), RE = end(); RI != RE; ++RI)
504 (*RI)->print(OS, print_tree, level + 1, Style);
505 }
506
507 if (Style != PrintNone)
508 OS.indent(level * 2) << "} \n";
509 }
510
511 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
512 template <class Tr>
dump()513 void RegionBase<Tr>::dump() const {
514 print(dbgs(), true, getDepth(), RegionInfoBase<Tr>::printStyle);
515 }
516 #endif
517
518 template <class Tr>
clearNodeCache()519 void RegionBase<Tr>::clearNodeCache() {
520 // Free the cached nodes.
521 for (typename BBNodeMapT::iterator I = BBNodeMap.begin(),
522 IE = BBNodeMap.end();
523 I != IE; ++I)
524 delete I->second;
525
526 BBNodeMap.clear();
527 for (typename RegionT::iterator RI = begin(), RE = end(); RI != RE; ++RI)
528 (*RI)->clearNodeCache();
529 }
530
531 //===----------------------------------------------------------------------===//
532 // RegionInfoBase implementation
533 //
534
535 template <class Tr>
RegionInfoBase()536 RegionInfoBase<Tr>::RegionInfoBase()
537 : TopLevelRegion(nullptr) {}
538
539 template <class Tr>
~RegionInfoBase()540 RegionInfoBase<Tr>::~RegionInfoBase() {
541 releaseMemory();
542 }
543
544 template <class Tr>
isCommonDomFrontier(BlockT * BB,BlockT * entry,BlockT * exit)545 bool RegionInfoBase<Tr>::isCommonDomFrontier(BlockT *BB, BlockT *entry,
546 BlockT *exit) const {
547 for (PredIterTy PI = InvBlockTraits::child_begin(BB),
548 PE = InvBlockTraits::child_end(BB);
549 PI != PE; ++PI) {
550 BlockT *P = *PI;
551 if (DT->dominates(entry, P) && !DT->dominates(exit, P))
552 return false;
553 }
554
555 return true;
556 }
557
558 template <class Tr>
isRegion(BlockT * entry,BlockT * exit)559 bool RegionInfoBase<Tr>::isRegion(BlockT *entry, BlockT *exit) const {
560 assert(entry && exit && "entry and exit must not be null!");
561 typedef typename DomFrontierT::DomSetType DST;
562
563 DST *entrySuccs = &DF->find(entry)->second;
564
565 // Exit is the header of a loop that contains the entry. In this case,
566 // the dominance frontier must only contain the exit.
567 if (!DT->dominates(entry, exit)) {
568 for (typename DST::iterator SI = entrySuccs->begin(),
569 SE = entrySuccs->end();
570 SI != SE; ++SI) {
571 if (*SI != exit && *SI != entry)
572 return false;
573 }
574
575 return true;
576 }
577
578 DST *exitSuccs = &DF->find(exit)->second;
579
580 // Do not allow edges leaving the region.
581 for (typename DST::iterator SI = entrySuccs->begin(), SE = entrySuccs->end();
582 SI != SE; ++SI) {
583 if (*SI == exit || *SI == entry)
584 continue;
585 if (exitSuccs->find(*SI) == exitSuccs->end())
586 return false;
587 if (!isCommonDomFrontier(*SI, entry, exit))
588 return false;
589 }
590
591 // Do not allow edges pointing into the region.
592 for (typename DST::iterator SI = exitSuccs->begin(), SE = exitSuccs->end();
593 SI != SE; ++SI) {
594 if (DT->properlyDominates(entry, *SI) && *SI != exit)
595 return false;
596 }
597
598 return true;
599 }
600
601 template <class Tr>
insertShortCut(BlockT * entry,BlockT * exit,BBtoBBMap * ShortCut)602 void RegionInfoBase<Tr>::insertShortCut(BlockT *entry, BlockT *exit,
603 BBtoBBMap *ShortCut) const {
604 assert(entry && exit && "entry and exit must not be null!");
605
606 typename BBtoBBMap::iterator e = ShortCut->find(exit);
607
608 if (e == ShortCut->end())
609 // No further region at exit available.
610 (*ShortCut)[entry] = exit;
611 else {
612 // We found a region e that starts at exit. Therefore (entry, e->second)
613 // is also a region, that is larger than (entry, exit). Insert the
614 // larger one.
615 BlockT *BB = e->second;
616 (*ShortCut)[entry] = BB;
617 }
618 }
619
620 template <class Tr>
621 typename Tr::DomTreeNodeT *
getNextPostDom(DomTreeNodeT * N,BBtoBBMap * ShortCut)622 RegionInfoBase<Tr>::getNextPostDom(DomTreeNodeT *N, BBtoBBMap *ShortCut) const {
623 typename BBtoBBMap::iterator e = ShortCut->find(N->getBlock());
624
625 if (e == ShortCut->end())
626 return N->getIDom();
627
628 return PDT->getNode(e->second)->getIDom();
629 }
630
631 template <class Tr>
isTrivialRegion(BlockT * entry,BlockT * exit)632 bool RegionInfoBase<Tr>::isTrivialRegion(BlockT *entry, BlockT *exit) const {
633 assert(entry && exit && "entry and exit must not be null!");
634
635 unsigned num_successors =
636 BlockTraits::child_end(entry) - BlockTraits::child_begin(entry);
637
638 if (num_successors <= 1 && exit == *(BlockTraits::child_begin(entry)))
639 return true;
640
641 return false;
642 }
643
644 template <class Tr>
createRegion(BlockT * entry,BlockT * exit)645 typename Tr::RegionT *RegionInfoBase<Tr>::createRegion(BlockT *entry,
646 BlockT *exit) {
647 assert(entry && exit && "entry and exit must not be null!");
648
649 if (isTrivialRegion(entry, exit))
650 return nullptr;
651
652 RegionT *region =
653 new RegionT(entry, exit, static_cast<RegionInfoT *>(this), DT);
654 BBtoRegion.insert(std::make_pair(entry, region));
655
656 #ifdef XDEBUG
657 region->verifyRegion();
658 #else
659 DEBUG(region->verifyRegion());
660 #endif
661
662 updateStatistics(region);
663 return region;
664 }
665
666 template <class Tr>
findRegionsWithEntry(BlockT * entry,BBtoBBMap * ShortCut)667 void RegionInfoBase<Tr>::findRegionsWithEntry(BlockT *entry,
668 BBtoBBMap *ShortCut) {
669 assert(entry);
670
671 DomTreeNodeT *N = PDT->getNode(entry);
672 if (!N)
673 return;
674
675 RegionT *lastRegion = nullptr;
676 BlockT *lastExit = entry;
677
678 // As only a BasicBlock that postdominates entry can finish a region, walk the
679 // post dominance tree upwards.
680 while ((N = getNextPostDom(N, ShortCut))) {
681 BlockT *exit = N->getBlock();
682
683 if (!exit)
684 break;
685
686 if (isRegion(entry, exit)) {
687 RegionT *newRegion = createRegion(entry, exit);
688
689 if (lastRegion)
690 newRegion->addSubRegion(lastRegion);
691
692 lastRegion = newRegion;
693 lastExit = exit;
694 }
695
696 // This can never be a region, so stop the search.
697 if (!DT->dominates(entry, exit))
698 break;
699 }
700
701 // Tried to create regions from entry to lastExit. Next time take a
702 // shortcut from entry to lastExit.
703 if (lastExit != entry)
704 insertShortCut(entry, lastExit, ShortCut);
705 }
706
707 template <class Tr>
scanForRegions(FuncT & F,BBtoBBMap * ShortCut)708 void RegionInfoBase<Tr>::scanForRegions(FuncT &F, BBtoBBMap *ShortCut) {
709 typedef typename std::add_pointer<FuncT>::type FuncPtrT;
710 BlockT *entry = GraphTraits<FuncPtrT>::getEntryNode(&F);
711 DomTreeNodeT *N = DT->getNode(entry);
712
713 // Iterate over the dominance tree in post order to start with the small
714 // regions from the bottom of the dominance tree. If the small regions are
715 // detected first, detection of bigger regions is faster, as we can jump
716 // over the small regions.
717 for (auto DomNode : post_order(N))
718 findRegionsWithEntry(DomNode->getBlock(), ShortCut);
719 }
720
721 template <class Tr>
getTopMostParent(RegionT * region)722 typename Tr::RegionT *RegionInfoBase<Tr>::getTopMostParent(RegionT *region) {
723 while (region->getParent())
724 region = region->getParent();
725
726 return region;
727 }
728
729 template <class Tr>
buildRegionsTree(DomTreeNodeT * N,RegionT * region)730 void RegionInfoBase<Tr>::buildRegionsTree(DomTreeNodeT *N, RegionT *region) {
731 BlockT *BB = N->getBlock();
732
733 // Passed region exit
734 while (BB == region->getExit())
735 region = region->getParent();
736
737 typename BBtoRegionMap::iterator it = BBtoRegion.find(BB);
738
739 // This basic block is a start block of a region. It is already in the
740 // BBtoRegion relation. Only the child basic blocks have to be updated.
741 if (it != BBtoRegion.end()) {
742 RegionT *newRegion = it->second;
743 region->addSubRegion(getTopMostParent(newRegion));
744 region = newRegion;
745 } else {
746 BBtoRegion[BB] = region;
747 }
748
749 for (typename DomTreeNodeT::iterator CI = N->begin(), CE = N->end(); CI != CE;
750 ++CI) {
751 buildRegionsTree(*CI, region);
752 }
753 }
754
755 #ifdef XDEBUG
756 template <class Tr>
757 bool RegionInfoBase<Tr>::VerifyRegionInfo = true;
758 #else
759 template <class Tr>
760 bool RegionInfoBase<Tr>::VerifyRegionInfo = false;
761 #endif
762
763 template <class Tr>
764 typename Tr::RegionT::PrintStyle RegionInfoBase<Tr>::printStyle =
765 RegionBase<Tr>::PrintNone;
766
767 template <class Tr>
print(raw_ostream & OS)768 void RegionInfoBase<Tr>::print(raw_ostream &OS) const {
769 OS << "Region tree:\n";
770 TopLevelRegion->print(OS, true, 0, printStyle);
771 OS << "End region tree\n";
772 }
773
774 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
775 template <class Tr>
dump()776 void RegionInfoBase<Tr>::dump() const { print(dbgs()); }
777 #endif
778
779 template <class Tr>
releaseMemory()780 void RegionInfoBase<Tr>::releaseMemory() {
781 BBtoRegion.clear();
782 if (TopLevelRegion)
783 delete TopLevelRegion;
784 TopLevelRegion = nullptr;
785 }
786
787 template <class Tr>
verifyAnalysis()788 void RegionInfoBase<Tr>::verifyAnalysis() const {
789 TopLevelRegion->verifyRegionNest();
790 }
791
792 // Region pass manager support.
793 template <class Tr>
getRegionFor(BlockT * BB)794 typename Tr::RegionT *RegionInfoBase<Tr>::getRegionFor(BlockT *BB) const {
795 typename BBtoRegionMap::const_iterator I = BBtoRegion.find(BB);
796 return I != BBtoRegion.end() ? I->second : nullptr;
797 }
798
799 template <class Tr>
setRegionFor(BlockT * BB,RegionT * R)800 void RegionInfoBase<Tr>::setRegionFor(BlockT *BB, RegionT *R) {
801 BBtoRegion[BB] = R;
802 }
803
804 template <class Tr>
805 typename Tr::RegionT *RegionInfoBase<Tr>::operator[](BlockT *BB) const {
806 return getRegionFor(BB);
807 }
808
809 template <class Tr>
810 typename RegionInfoBase<Tr>::BlockT *
getMaxRegionExit(BlockT * BB)811 RegionInfoBase<Tr>::getMaxRegionExit(BlockT *BB) const {
812 BlockT *Exit = nullptr;
813
814 while (true) {
815 // Get largest region that starts at BB.
816 RegionT *R = getRegionFor(BB);
817 while (R && R->getParent() && R->getParent()->getEntry() == BB)
818 R = R->getParent();
819
820 // Get the single exit of BB.
821 if (R && R->getEntry() == BB)
822 Exit = R->getExit();
823 else if (++BlockTraits::child_begin(BB) == BlockTraits::child_end(BB))
824 Exit = *BlockTraits::child_begin(BB);
825 else // No single exit exists.
826 return Exit;
827
828 // Get largest region that starts at Exit.
829 RegionT *ExitR = getRegionFor(Exit);
830 while (ExitR && ExitR->getParent() &&
831 ExitR->getParent()->getEntry() == Exit)
832 ExitR = ExitR->getParent();
833
834 for (PredIterTy PI = InvBlockTraits::child_begin(Exit),
835 PE = InvBlockTraits::child_end(Exit);
836 PI != PE; ++PI) {
837 if (!R->contains(*PI) && !ExitR->contains(*PI))
838 break;
839 }
840
841 // This stops infinite cycles.
842 if (DT->dominates(Exit, BB))
843 break;
844
845 BB = Exit;
846 }
847
848 return Exit;
849 }
850
851 template <class Tr>
getCommonRegion(RegionT * A,RegionT * B)852 typename Tr::RegionT *RegionInfoBase<Tr>::getCommonRegion(RegionT *A,
853 RegionT *B) const {
854 assert(A && B && "One of the Regions is NULL");
855
856 if (A->contains(B))
857 return A;
858
859 while (!B->contains(A))
860 B = B->getParent();
861
862 return B;
863 }
864
865 template <class Tr>
866 typename Tr::RegionT *
getCommonRegion(SmallVectorImpl<RegionT * > & Regions)867 RegionInfoBase<Tr>::getCommonRegion(SmallVectorImpl<RegionT *> &Regions) const {
868 RegionT *ret = Regions.back();
869 Regions.pop_back();
870
871 for (RegionT *R : Regions)
872 ret = getCommonRegion(ret, R);
873
874 return ret;
875 }
876
877 template <class Tr>
878 typename Tr::RegionT *
getCommonRegion(SmallVectorImpl<BlockT * > & BBs)879 RegionInfoBase<Tr>::getCommonRegion(SmallVectorImpl<BlockT *> &BBs) const {
880 RegionT *ret = getRegionFor(BBs.back());
881 BBs.pop_back();
882
883 for (BlockT *BB : BBs)
884 ret = getCommonRegion(ret, getRegionFor(BB));
885
886 return ret;
887 }
888
889 template <class Tr>
splitBlock(BlockT * NewBB,BlockT * OldBB)890 void RegionInfoBase<Tr>::splitBlock(BlockT *NewBB, BlockT *OldBB) {
891 RegionT *R = getRegionFor(OldBB);
892
893 setRegionFor(NewBB, R);
894
895 while (R->getEntry() == OldBB && !R->isTopLevelRegion()) {
896 R->replaceEntry(NewBB);
897 R = R->getParent();
898 }
899
900 setRegionFor(OldBB, R);
901 }
902
903 template <class Tr>
calculate(FuncT & F)904 void RegionInfoBase<Tr>::calculate(FuncT &F) {
905 typedef typename std::add_pointer<FuncT>::type FuncPtrT;
906
907 // ShortCut a function where for every BB the exit of the largest region
908 // starting with BB is stored. These regions can be threated as single BBS.
909 // This improves performance on linear CFGs.
910 BBtoBBMap ShortCut;
911
912 scanForRegions(F, &ShortCut);
913 BlockT *BB = GraphTraits<FuncPtrT>::getEntryNode(&F);
914 buildRegionsTree(DT->getNode(BB), TopLevelRegion);
915 }
916
917 #undef DEBUG_TYPE
918
919 } // end namespace llvm
920
921 #endif
922