1 //===- RegionInfo.h - SESE region analysis ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Calculate a program structure tree built out of single entry single exit
12 // The basic ideas are taken from "The Program Structure Tree - Richard Johnson,
13 // David Pearson, Keshav Pingali - 1994", however enriched with ideas from "The
14 // Refined Process Structure Tree - Jussi Vanhatalo, Hagen Voelyer, Jana
16 // The algorithm to calculate these data structures however is completely
17 // different, as it takes advantage of existing information already available
18 // in (Post)dominace tree and dominance frontier passes. This leads to a simpler
19 // and in practice hopefully better performing algorithm. The runtime of the
20 // algorithms described in the papers above are both linear in graph size,
21 // O(V+E), whereas this algorithm is not, as the dominance frontier information
22 // itself is not, but in practice runtime seems to be in the order of magnitude
23 // of dominance tree calculation.
25 // WARNING: LLVM is generally very concerned about compile time such that
26 // the use of additional analysis passes in the default
27 // optimization sequence is avoided as much as possible.
28 // Specifically, if you do not need the RegionInfo, but dominance
29 // information could be sufficient please base your work only on
30 // the dominator tree. Most passes maintain it, such that using
31 // it has often near zero cost. In contrast RegionInfo is by
32 // default not available, is not maintained by existing
33 // transformations and there is no intention to do so.
35 //===----------------------------------------------------------------------===//
37 #ifndef LLVM_ANALYSIS_REGIONINFO_H
38 #define LLVM_ANALYSIS_REGIONINFO_H
40 #include "llvm/ADT/DepthFirstIterator.h"
41 #include "llvm/ADT/PointerIntPair.h"
42 #include "llvm/IR/CFG.h"
43 #include "llvm/IR/Dominators.h"
50 // RegionTraits - Class to be specialized for different users of RegionInfo
51 // (i.e. BasicBlocks or MachineBasicBlocks). This is only to avoid needing to
52 // pass around an unreasonable number of template parameters.
53 template <class FuncT_>
60 typedef typename FuncT_::UnknownRegionTypeError BrokenT;
64 class DominanceFrontier;
67 struct PostDominatorTree;
70 template <class RegionTr>
74 template <class RegionTr>
78 struct RegionTraits<Function> {
79 typedef Function FuncT;
80 typedef BasicBlock BlockT;
81 typedef Region RegionT;
82 typedef RegionNode RegionNodeT;
83 typedef RegionInfo RegionInfoT;
84 typedef DominatorTree DomTreeT;
85 typedef DomTreeNode DomTreeNodeT;
86 typedef DominanceFrontier DomFrontierT;
87 typedef PostDominatorTree PostDomTreeT;
88 typedef Instruction InstT;
90 typedef LoopInfo LoopInfoT;
92 static unsigned getNumSuccessors(BasicBlock *BB) {
93 return BB->getTerminator()->getNumSuccessors();
97 /// @brief Marker class to iterate over the elements of a Region in flat mode.
99 /// The class is used to either iterate in Flat mode or by not using it to not
100 /// iterate in Flat mode. During a Flat mode iteration all Regions are entered
101 /// and the iteration returns every BasicBlock. If the Flat mode is not
102 /// selected for SubRegions just one RegionNode containing the subregion is
104 template <class GraphType>
107 /// @brief A RegionNode represents a subregion or a BasicBlock that is part of a
110 class RegionNodeBase {
111 friend class RegionBase<Tr>;
114 typedef typename Tr::BlockT BlockT;
115 typedef typename Tr::RegionT RegionT;
118 RegionNodeBase(const RegionNodeBase &) = delete;
119 const RegionNodeBase &operator=(const RegionNodeBase &) = delete;
121 /// This is the entry basic block that starts this region node. If this is a
122 /// BasicBlock RegionNode, then entry is just the basic block, that this
123 /// RegionNode represents. Otherwise it is the entry of this (Sub)RegionNode.
125 /// In the BBtoRegionNode map of the parent of this node, BB will always map
126 /// to this node no matter which kind of node this one is.
128 /// The node can hold either a Region or a BasicBlock.
129 /// Use one bit to save, if this RegionNode is a subregion or BasicBlock
131 PointerIntPair<BlockT *, 1, bool> entry;
133 /// @brief The parent Region of this RegionNode.
138 /// @brief Create a RegionNode.
140 /// @param Parent The parent of this RegionNode.
141 /// @param Entry The entry BasicBlock of the RegionNode. If this
142 /// RegionNode represents a BasicBlock, this is the
143 /// BasicBlock itself. If it represents a subregion, this
144 /// is the entry BasicBlock of the subregion.
145 /// @param isSubRegion If this RegionNode represents a SubRegion.
146 inline RegionNodeBase(RegionT *Parent, BlockT *Entry,
147 bool isSubRegion = false)
148 : entry(Entry, isSubRegion), parent(Parent) {}
151 /// @brief Get the parent Region of this RegionNode.
153 /// The parent Region is the Region this RegionNode belongs to. If for
154 /// example a BasicBlock is element of two Regions, there exist two
155 /// RegionNodes for this BasicBlock. Each with the getParent() function
156 /// pointing to the Region this RegionNode belongs to.
158 /// @return Get the parent Region of this RegionNode.
159 inline RegionT *getParent() const { return parent; }
161 /// @brief Get the entry BasicBlock of this RegionNode.
163 /// If this RegionNode represents a BasicBlock this is just the BasicBlock
164 /// itself, otherwise we return the entry BasicBlock of the Subregion
166 /// @return The entry BasicBlock of this RegionNode.
167 inline BlockT *getEntry() const { return entry.getPointer(); }
169 /// @brief Get the content of this RegionNode.
171 /// This can be either a BasicBlock or a subregion. Before calling getNodeAs()
172 /// check the type of the content with the isSubRegion() function call.
174 /// @return The content of this RegionNode.
175 template <class T> inline T *getNodeAs() const;
177 /// @brief Is this RegionNode a subregion?
179 /// @return True if it contains a subregion. False if it contains a
181 inline bool isSubRegion() const { return entry.getInt(); }
184 //===----------------------------------------------------------------------===//
185 /// @brief A single entry single exit Region.
187 /// A Region is a connected subgraph of a control flow graph that has exactly
188 /// two connections to the remaining graph. It can be used to analyze or
189 /// optimize parts of the control flow graph.
191 /// A <em> simple Region </em> is connected to the remaining graph by just two
192 /// edges. One edge entering the Region and another one leaving the Region.
194 /// An <em> extended Region </em> (or just Region) is a subgraph that can be
195 /// transform into a simple Region. The transformation is done by adding
196 /// BasicBlocks that merge several entry or exit edges so that after the merge
197 /// just one entry and one exit edge exists.
199 /// The \e Entry of a Region is the first BasicBlock that is passed after
200 /// entering the Region. It is an element of the Region. The entry BasicBlock
201 /// dominates all BasicBlocks in the Region.
203 /// The \e Exit of a Region is the first BasicBlock that is passed after
204 /// leaving the Region. It is not an element of the Region. The exit BasicBlock,
205 /// postdominates all BasicBlocks in the Region.
207 /// A <em> canonical Region </em> cannot be constructed by combining smaller
210 /// Region A is the \e parent of Region B, if B is completely contained in A.
212 /// Two canonical Regions either do not intersect at all or one is
213 /// the parent of the other.
215 /// The <em> Program Structure Tree</em> is a graph (V, E) where V is the set of
216 /// Regions in the control flow graph and E is the \e parent relation of these
222 /// A simple control flow graph, that contains two regions.
232 /// \ |/ Region A: 1 -> 9 {1,2,3,4,5,6,7,8}
233 /// 9 Region B: 2 -> 9 {2,4,5,6,7}
236 /// You can obtain more examples by either calling
238 /// <tt> "opt -regions -analyze anyprogram.ll" </tt>
240 /// <tt> "opt -view-regions-only anyprogram.ll" </tt>
242 /// on any LLVM file you are interested in.
244 /// The first call returns a textual representation of the program structure
245 /// tree, the second one creates a graphical representation using graphviz.
247 class RegionBase : public RegionNodeBase<Tr> {
248 typedef typename Tr::FuncT FuncT;
249 typedef typename Tr::BlockT BlockT;
250 typedef typename Tr::RegionInfoT RegionInfoT;
251 typedef typename Tr::RegionT RegionT;
252 typedef typename Tr::RegionNodeT RegionNodeT;
253 typedef typename Tr::DomTreeT DomTreeT;
254 typedef typename Tr::LoopT LoopT;
255 typedef typename Tr::LoopInfoT LoopInfoT;
256 typedef typename Tr::InstT InstT;
258 typedef GraphTraits<BlockT *> BlockTraits;
259 typedef GraphTraits<Inverse<BlockT *>> InvBlockTraits;
260 typedef typename BlockTraits::ChildIteratorType SuccIterTy;
261 typedef typename InvBlockTraits::ChildIteratorType PredIterTy;
263 friend class RegionInfoBase<Tr>;
264 RegionBase(const RegionBase &) = delete;
265 const RegionBase &operator=(const RegionBase &) = delete;
267 // Information necessary to manage this Region.
271 // The exit BasicBlock of this region.
272 // (The entry BasicBlock is part of RegionNode)
275 typedef std::vector<std::unique_ptr<RegionT>> RegionSet;
277 // The subregions of this region.
280 typedef std::map<BlockT *, RegionNodeT *> BBNodeMapT;
282 // Save the BasicBlock RegionNodes that are element of this Region.
283 mutable BBNodeMapT BBNodeMap;
285 /// verifyBBInRegion - Check if a BB is in this Region. This check also works
286 /// if the region is incorrectly built. (EXPENSIVE!)
287 void verifyBBInRegion(BlockT *BB) const;
289 /// verifyWalk - Walk over all the BBs of the region starting from BB and
290 /// verify that all reachable basic blocks are elements of the region.
292 void verifyWalk(BlockT *BB, std::set<BlockT *> *visitedBB) const;
294 /// verifyRegionNest - Verify if the region and its children are valid
295 /// regions (EXPENSIVE!)
296 void verifyRegionNest() const;
299 /// @brief Create a new region.
301 /// @param Entry The entry basic block of the region.
302 /// @param Exit The exit basic block of the region.
303 /// @param RI The region info object that is managing this region.
304 /// @param DT The dominator tree of the current function.
305 /// @param Parent The surrounding region or NULL if this is a top level
307 RegionBase(BlockT *Entry, BlockT *Exit, RegionInfoT *RI, DomTreeT *DT,
308 RegionT *Parent = nullptr);
310 /// Delete the Region and all its subregions.
313 /// @brief Get the entry BasicBlock of the Region.
314 /// @return The entry BasicBlock of the region.
315 BlockT *getEntry() const {
316 return RegionNodeBase<Tr>::getEntry();
319 /// @brief Replace the entry basic block of the region with the new basic
322 /// @param BB The new entry basic block of the region.
323 void replaceEntry(BlockT *BB);
325 /// @brief Replace the exit basic block of the region with the new basic
328 /// @param BB The new exit basic block of the region.
329 void replaceExit(BlockT *BB);
331 /// @brief Recursively replace the entry basic block of the region.
333 /// This function replaces the entry basic block with a new basic block. It
334 /// also updates all child regions that have the same entry basic block as
337 /// @param NewEntry The new entry basic block.
338 void replaceEntryRecursive(BlockT *NewEntry);
340 /// @brief Recursively replace the exit basic block of the region.
342 /// This function replaces the exit basic block with a new basic block. It
343 /// also updates all child regions that have the same exit basic block as
346 /// @param NewExit The new exit basic block.
347 void replaceExitRecursive(BlockT *NewExit);
349 /// @brief Get the exit BasicBlock of the Region.
350 /// @return The exit BasicBlock of the Region, NULL if this is the TopLevel
352 BlockT *getExit() const { return exit; }
354 /// @brief Get the parent of the Region.
355 /// @return The parent of the Region or NULL if this is a top level
357 RegionT *getParent() const {
358 return RegionNodeBase<Tr>::getParent();
361 /// @brief Get the RegionNode representing the current Region.
362 /// @return The RegionNode representing the current Region.
363 RegionNodeT *getNode() const {
364 return const_cast<RegionNodeT *>(
365 reinterpret_cast<const RegionNodeT *>(this));
368 /// @brief Get the nesting level of this Region.
370 /// An toplevel Region has depth 0.
372 /// @return The depth of the region.
373 unsigned getDepth() const;
375 /// @brief Check if a Region is the TopLevel region.
377 /// The toplevel region represents the whole function.
378 bool isTopLevelRegion() const { return exit == nullptr; }
380 /// @brief Return a new (non-canonical) region, that is obtained by joining
381 /// this region with its predecessors.
383 /// @return A region also starting at getEntry(), but reaching to the next
384 /// basic block that forms with getEntry() a (non-canonical) region.
385 /// NULL if such a basic block does not exist.
386 RegionT *getExpandedRegion() const;
388 /// @brief Return the first block of this region's single entry edge,
391 /// @return The BasicBlock starting this region's single entry edge,
393 BlockT *getEnteringBlock() const;
395 /// @brief Return the first block of this region's single exit edge,
398 /// @return The BasicBlock starting this region's single exit edge,
400 BlockT *getExitingBlock() const;
402 /// @brief Is this a simple region?
404 /// A region is simple if it has exactly one exit and one entry edge.
406 /// @return True if the Region is simple.
407 bool isSimple() const;
409 /// @brief Returns the name of the Region.
410 /// @return The Name of the Region.
411 std::string getNameStr() const;
413 /// @brief Return the RegionInfo object, that belongs to this Region.
414 RegionInfoT *getRegionInfo() const { return RI; }
416 /// PrintStyle - Print region in difference ways.
417 enum PrintStyle { PrintNone, PrintBB, PrintRN };
419 /// @brief Print the region.
421 /// @param OS The output stream the Region is printed to.
422 /// @param printTree Print also the tree of subregions.
423 /// @param level The indentation level used for printing.
424 void print(raw_ostream &OS, bool printTree = true, unsigned level = 0,
425 PrintStyle Style = PrintNone) const;
427 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
428 /// @brief Print the region to stderr.
432 /// @brief Check if the region contains a BasicBlock.
434 /// @param BB The BasicBlock that might be contained in this Region.
435 /// @return True if the block is contained in the region otherwise false.
436 bool contains(const BlockT *BB) const;
438 /// @brief Check if the region contains another region.
440 /// @param SubRegion The region that might be contained in this Region.
441 /// @return True if SubRegion is contained in the region otherwise false.
442 bool contains(const RegionT *SubRegion) const {
447 return contains(SubRegion->getEntry()) &&
448 (contains(SubRegion->getExit()) ||
449 SubRegion->getExit() == getExit());
452 /// @brief Check if the region contains an Instruction.
454 /// @param Inst The Instruction that might be contained in this region.
455 /// @return True if the Instruction is contained in the region otherwise
457 bool contains(const InstT *Inst) const { return contains(Inst->getParent()); }
459 /// @brief Check if the region contains a loop.
461 /// @param L The loop that might be contained in this region.
462 /// @return True if the loop is contained in the region otherwise false.
463 /// In case a NULL pointer is passed to this function the result
464 /// is false, except for the region that describes the whole function.
465 /// In that case true is returned.
466 bool contains(const LoopT *L) const;
468 /// @brief Get the outermost loop in the region that contains a loop.
470 /// Find for a Loop L the outermost loop OuterL that is a parent loop of L
471 /// and is itself contained in the region.
473 /// @param L The loop the lookup is started.
474 /// @return The outermost loop in the region, NULL if such a loop does not
475 /// exist or if the region describes the whole function.
476 LoopT *outermostLoopInRegion(LoopT *L) const;
478 /// @brief Get the outermost loop in the region that contains a basic block.
480 /// Find for a basic block BB the outermost loop L that contains BB and is
481 /// itself contained in the region.
483 /// @param LI A pointer to a LoopInfo analysis.
484 /// @param BB The basic block surrounded by the loop.
485 /// @return The outermost loop in the region, NULL if such a loop does not
486 /// exist or if the region describes the whole function.
487 LoopT *outermostLoopInRegion(LoopInfoT *LI, BlockT *BB) const;
489 /// @brief Get the subregion that starts at a BasicBlock
491 /// @param BB The BasicBlock the subregion should start.
492 /// @return The Subregion if available, otherwise NULL.
493 RegionT *getSubRegionNode(BlockT *BB) const;
495 /// @brief Get the RegionNode for a BasicBlock
497 /// @param BB The BasicBlock at which the RegionNode should start.
498 /// @return If available, the RegionNode that represents the subregion
499 /// starting at BB. If no subregion starts at BB, the RegionNode
501 RegionNodeT *getNode(BlockT *BB) const;
503 /// @brief Get the BasicBlock RegionNode for a BasicBlock
505 /// @param BB The BasicBlock for which the RegionNode is requested.
506 /// @return The RegionNode representing the BB.
507 RegionNodeT *getBBNode(BlockT *BB) const;
509 /// @brief Add a new subregion to this Region.
511 /// @param SubRegion The new subregion that will be added.
512 /// @param moveChildren Move the children of this region, that are also
513 /// contained in SubRegion into SubRegion.
514 void addSubRegion(RegionT *SubRegion, bool moveChildren = false);
516 /// @brief Remove a subregion from this Region.
518 /// The subregion is not deleted, as it will probably be inserted into another
520 /// @param SubRegion The SubRegion that will be removed.
521 RegionT *removeSubRegion(RegionT *SubRegion);
523 /// @brief Move all direct child nodes of this Region to another Region.
525 /// @param To The Region the child nodes will be transferred to.
526 void transferChildrenTo(RegionT *To);
528 /// @brief Verify if the region is a correct region.
530 /// Check if this is a correctly build Region. This is an expensive check, as
531 /// the complete CFG of the Region will be walked.
532 void verifyRegion() const;
534 /// @brief Clear the cache for BB RegionNodes.
536 /// After calling this function the BasicBlock RegionNodes will be stored at
537 /// different memory locations. RegionNodes obtained before this function is
538 /// called are therefore not comparable to RegionNodes abtained afterwords.
539 void clearNodeCache();
541 /// @name Subregion Iterators
543 /// These iterators iterator over all subregions of this Region.
545 typedef typename RegionSet::iterator iterator;
546 typedef typename RegionSet::const_iterator const_iterator;
548 iterator begin() { return children.begin(); }
549 iterator end() { return children.end(); }
551 const_iterator begin() const { return children.begin(); }
552 const_iterator end() const { return children.end(); }
555 /// @name BasicBlock Iterators
557 /// These iterators iterate over all BasicBlocks that are contained in this
558 /// Region. The iterator also iterates over BasicBlocks that are elements of
559 /// a subregion of this Region. It is therefore called a flat iterator.
561 template <bool IsConst>
562 class block_iterator_wrapper
563 : public df_iterator<
564 typename std::conditional<IsConst, const BlockT, BlockT>::type *> {
566 typename std::conditional<IsConst, const BlockT, BlockT>::type *> super;
569 typedef block_iterator_wrapper<IsConst> Self;
570 typedef typename super::pointer pointer;
572 // Construct the begin iterator.
573 block_iterator_wrapper(pointer Entry, pointer Exit)
574 : super(df_begin(Entry)) {
575 // Mark the exit of the region as visited, so that the children of the
576 // exit and the exit itself, i.e. the block outside the region will never
578 super::Visited.insert(Exit);
581 // Construct the end iterator.
582 block_iterator_wrapper() : super(df_end<pointer>((BlockT *)nullptr)) {}
584 /*implicit*/ block_iterator_wrapper(super I) : super(I) {}
586 // FIXME: Even a const_iterator returns a non-const BasicBlock pointer.
587 // This was introduced for backwards compatibility, but should
588 // be removed as soon as all users are fixed.
589 BlockT *operator*() const {
590 return const_cast<BlockT *>(super::operator*());
594 typedef block_iterator_wrapper<false> block_iterator;
595 typedef block_iterator_wrapper<true> const_block_iterator;
597 block_iterator block_begin() { return block_iterator(getEntry(), getExit()); }
599 block_iterator block_end() { return block_iterator(); }
601 const_block_iterator block_begin() const {
602 return const_block_iterator(getEntry(), getExit());
604 const_block_iterator block_end() const { return const_block_iterator(); }
606 typedef iterator_range<block_iterator> block_range;
607 typedef iterator_range<const_block_iterator> const_block_range;
609 /// @brief Returns a range view of the basic blocks in the region.
610 inline block_range blocks() {
611 return block_range(block_begin(), block_end());
614 /// @brief Returns a range view of the basic blocks in the region.
616 /// This is the 'const' version of the range view.
617 inline const_block_range blocks() const {
618 return const_block_range(block_begin(), block_end());
622 /// @name Element Iterators
624 /// These iterators iterate over all BasicBlock and subregion RegionNodes that
625 /// are direct children of this Region. It does not iterate over any
626 /// RegionNodes that are also element of a subregion of this Region.
628 typedef df_iterator<RegionNodeT *, SmallPtrSet<RegionNodeT *, 8>, false,
629 GraphTraits<RegionNodeT *>> element_iterator;
631 typedef df_iterator<const RegionNodeT *, SmallPtrSet<const RegionNodeT *, 8>,
633 GraphTraits<const RegionNodeT *>> const_element_iterator;
635 element_iterator element_begin();
636 element_iterator element_end();
638 const_element_iterator element_begin() const;
639 const_element_iterator element_end() const;
643 /// Print a RegionNode.
645 inline raw_ostream &operator<<(raw_ostream &OS, const RegionNodeBase<Tr> &Node);
647 //===----------------------------------------------------------------------===//
648 /// @brief Analysis that detects all canonical Regions.
650 /// The RegionInfo pass detects all canonical regions in a function. The Regions
651 /// are connected using the parent relation. This builds a Program Structure
654 class RegionInfoBase {
655 typedef typename Tr::BlockT BlockT;
656 typedef typename Tr::FuncT FuncT;
657 typedef typename Tr::RegionT RegionT;
658 typedef typename Tr::RegionInfoT RegionInfoT;
659 typedef typename Tr::DomTreeT DomTreeT;
660 typedef typename Tr::DomTreeNodeT DomTreeNodeT;
661 typedef typename Tr::PostDomTreeT PostDomTreeT;
662 typedef typename Tr::DomFrontierT DomFrontierT;
663 typedef GraphTraits<BlockT *> BlockTraits;
664 typedef GraphTraits<Inverse<BlockT *>> InvBlockTraits;
665 typedef typename BlockTraits::ChildIteratorType SuccIterTy;
666 typedef typename InvBlockTraits::ChildIteratorType PredIterTy;
668 friend class RegionInfo;
669 friend class MachineRegionInfo;
670 typedef DenseMap<BlockT *, BlockT *> BBtoBBMap;
671 typedef DenseMap<BlockT *, RegionT *> BBtoRegionMap;
672 typedef SmallPtrSet<RegionT *, 4> RegionSet;
675 virtual ~RegionInfoBase();
677 RegionInfoBase(const RegionInfoBase &) = delete;
678 const RegionInfoBase &operator=(const RegionInfoBase &) = delete;
684 /// The top level region.
685 RegionT *TopLevelRegion;
688 /// Map every BB to the smallest region, that contains BB.
689 BBtoRegionMap BBtoRegion;
691 // isCommonDomFrontier - Returns true if BB is in the dominance frontier of
692 // entry, because it was inherited from exit. In the other case there is an
693 // edge going from entry to BB without passing exit.
694 bool isCommonDomFrontier(BlockT *BB, BlockT *entry, BlockT *exit) const;
696 // isRegion - Check if entry and exit surround a valid region, based on
697 // dominance tree and dominance frontier.
698 bool isRegion(BlockT *entry, BlockT *exit) const;
700 // insertShortCut - Saves a shortcut pointing from entry to exit.
701 // This function may extend this shortcut if possible.
702 void insertShortCut(BlockT *entry, BlockT *exit, BBtoBBMap *ShortCut) const;
704 // getNextPostDom - Returns the next BB that postdominates N, while skipping
705 // all post dominators that cannot finish a canonical region.
706 DomTreeNodeT *getNextPostDom(DomTreeNodeT *N, BBtoBBMap *ShortCut) const;
708 // isTrivialRegion - A region is trivial, if it contains only one BB.
709 bool isTrivialRegion(BlockT *entry, BlockT *exit) const;
711 // createRegion - Creates a single entry single exit region.
712 RegionT *createRegion(BlockT *entry, BlockT *exit);
714 // findRegionsWithEntry - Detect all regions starting with bb 'entry'.
715 void findRegionsWithEntry(BlockT *entry, BBtoBBMap *ShortCut);
717 // scanForRegions - Detects regions in F.
718 void scanForRegions(FuncT &F, BBtoBBMap *ShortCut);
720 // getTopMostParent - Get the top most parent with the same entry block.
721 RegionT *getTopMostParent(RegionT *region);
723 // buildRegionsTree - build the region hierarchy after all region detected.
724 void buildRegionsTree(DomTreeNodeT *N, RegionT *region);
726 // updateStatistics - Update statistic about created regions.
727 virtual void updateStatistics(RegionT *R) = 0;
729 // calculate - detect all regions in function and build the region tree.
730 void calculate(FuncT &F);
733 static bool VerifyRegionInfo;
734 static typename RegionT::PrintStyle printStyle;
736 void print(raw_ostream &OS) const;
737 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
741 void releaseMemory();
743 /// @brief Get the smallest region that contains a BasicBlock.
745 /// @param BB The basic block.
746 /// @return The smallest region, that contains BB or NULL, if there is no
747 /// region containing BB.
748 RegionT *getRegionFor(BlockT *BB) const;
750 /// @brief Set the smallest region that surrounds a basic block.
752 /// @param BB The basic block surrounded by a region.
753 /// @param R The smallest region that surrounds BB.
754 void setRegionFor(BlockT *BB, RegionT *R);
756 /// @brief A shortcut for getRegionFor().
758 /// @param BB The basic block.
759 /// @return The smallest region, that contains BB or NULL, if there is no
760 /// region containing BB.
761 RegionT *operator[](BlockT *BB) const;
763 /// @brief Return the exit of the maximal refined region, that starts at a
766 /// @param BB The BasicBlock the refined region starts.
767 BlockT *getMaxRegionExit(BlockT *BB) const;
769 /// @brief Find the smallest region that contains two regions.
771 /// @param A The first region.
772 /// @param B The second region.
773 /// @return The smallest region containing A and B.
774 RegionT *getCommonRegion(RegionT *A, RegionT *B) const;
776 /// @brief Find the smallest region that contains two basic blocks.
778 /// @param A The first basic block.
779 /// @param B The second basic block.
780 /// @return The smallest region that contains A and B.
781 RegionT *getCommonRegion(BlockT *A, BlockT *B) const {
782 return getCommonRegion(getRegionFor(A), getRegionFor(B));
785 /// @brief Find the smallest region that contains a set of regions.
787 /// @param Regions A vector of regions.
788 /// @return The smallest region that contains all regions in Regions.
789 RegionT *getCommonRegion(SmallVectorImpl<RegionT *> &Regions) const;
791 /// @brief Find the smallest region that contains a set of basic blocks.
793 /// @param BBs A vector of basic blocks.
794 /// @return The smallest region that contains all basic blocks in BBS.
795 RegionT *getCommonRegion(SmallVectorImpl<BlockT *> &BBs) const;
797 RegionT *getTopLevelRegion() const { return TopLevelRegion; }
799 /// @brief Update RegionInfo after a basic block was split.
801 /// @param NewBB The basic block that was created before OldBB.
802 /// @param OldBB The old basic block.
803 void splitBlock(BlockT *NewBB, BlockT *OldBB);
805 /// @brief Clear the Node Cache for all Regions.
807 /// @see Region::clearNodeCache()
808 void clearNodeCache() {
810 TopLevelRegion->clearNodeCache();
813 void verifyAnalysis() const;
818 class RegionNode : public RegionNodeBase<RegionTraits<Function>> {
820 inline RegionNode(Region *Parent, BasicBlock *Entry, bool isSubRegion = false)
821 : RegionNodeBase<RegionTraits<Function>>(Parent, Entry, isSubRegion) {}
825 bool operator==(const Region &RN) const {
826 return this == reinterpret_cast<const RegionNode *>(&RN);
830 class Region : public RegionBase<RegionTraits<Function>> {
832 Region(BasicBlock *Entry, BasicBlock *Exit, RegionInfo *RI, DominatorTree *DT,
833 Region *Parent = nullptr);
836 bool operator==(const RegionNode &RN) const {
837 return &RN == reinterpret_cast<const RegionNode *>(this);
841 class RegionInfo : public RegionInfoBase<RegionTraits<Function>> {
843 explicit RegionInfo();
845 virtual ~RegionInfo();
847 // updateStatistics - Update statistic about created regions.
848 void updateStatistics(Region *R) final;
850 void recalculate(Function &F, DominatorTree *DT, PostDominatorTree *PDT,
851 DominanceFrontier *DF);
854 class RegionInfoPass : public FunctionPass {
859 explicit RegionInfoPass();
863 RegionInfo &getRegionInfo() { return RI; }
865 const RegionInfo &getRegionInfo() const { return RI; }
867 /// @name FunctionPass interface
869 bool runOnFunction(Function &F) override;
870 void releaseMemory() override;
871 void verifyAnalysis() const override;
872 void getAnalysisUsage(AnalysisUsage &AU) const override;
873 void print(raw_ostream &OS, const Module *) const override;
881 RegionNodeBase<RegionTraits<Function>>::getNodeAs<BasicBlock>() const {
882 assert(!isSubRegion() && "This is not a BasicBlock RegionNode!");
889 RegionNodeBase<RegionTraits<Function>>::getNodeAs<Region>() const {
890 assert(isSubRegion() && "This is not a subregion RegionNode!");
891 auto Unconst = const_cast<RegionNodeBase<RegionTraits<Function>> *>(this);
892 return reinterpret_cast<Region *>(Unconst);
896 inline raw_ostream &operator<<(raw_ostream &OS,
897 const RegionNodeBase<Tr> &Node) {
898 typedef typename Tr::BlockT BlockT;
899 typedef typename Tr::RegionT RegionT;
901 if (Node.isSubRegion())
902 return OS << Node.template getNodeAs<RegionT>()->getNameStr();
904 return OS << Node.template getNodeAs<BlockT>()->getName();
907 EXTERN_TEMPLATE_INSTANTIATION(class RegionBase<RegionTraits<Function>>);
908 EXTERN_TEMPLATE_INSTANTIATION(class RegionNodeBase<RegionTraits<Function>>);
909 EXTERN_TEMPLATE_INSTANTIATION(class RegionInfoBase<RegionTraits<Function>>);
911 } // End llvm namespace