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RegionInfo.h
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1 //===- RegionInfo.h - SESE region 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 //
10 // Calculate a program structure tree built out of single entry single exit
11 // regions.
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
15 // Koehler - 2009".
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.
24 //
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.
34 //
35 //===----------------------------------------------------------------------===//
36 
37 #ifndef LLVM_ANALYSIS_REGIONINFO_H
38 #define LLVM_ANALYSIS_REGIONINFO_H
39 
40 #include "llvm/ADT/DenseMap.h"
42 #include "llvm/ADT/GraphTraits.h"
45 #include "llvm/IR/BasicBlock.h"
46 #include "llvm/IR/Dominators.h"
47 #include "llvm/IR/PassManager.h"
48 #include "llvm/Pass.h"
50 #include <algorithm>
51 #include <cassert>
52 #include <map>
53 #include <memory>
54 #include <set>
55 #include <string>
56 #include <type_traits>
57 #include <vector>
58 
59 namespace llvm {
60 
61 class DominanceFrontier;
62 class DominatorTree;
63 class Loop;
64 class LoopInfo;
65 struct PostDominatorTree;
66 class Region;
67 template <class RegionTr> class RegionBase;
68 class RegionInfo;
69 template <class RegionTr> class RegionInfoBase;
70 class RegionNode;
71 
72 // Class to be specialized for different users of RegionInfo
73 // (i.e. BasicBlocks or MachineBasicBlocks). This is only to avoid needing to
74 // pass around an unreasonable number of template parameters.
75 template <class FuncT_>
76 struct RegionTraits {
77  // FuncT
78  // BlockT
79  // RegionT
80  // RegionNodeT
81  // RegionInfoT
82  using BrokenT = typename FuncT_::UnknownRegionTypeError;
83 };
84 
85 template <>
87  using FuncT = Function;
88  using BlockT = BasicBlock;
89  using RegionT = Region;
96  using InstT = Instruction;
97  using LoopT = Loop;
99 
100  static unsigned getNumSuccessors(BasicBlock *BB) {
101  return BB->getTerminator()->getNumSuccessors();
102  }
103 };
104 
105 /// @brief Marker class to iterate over the elements of a Region in flat mode.
106 ///
107 /// The class is used to either iterate in Flat mode or by not using it to not
108 /// iterate in Flat mode. During a Flat mode iteration all Regions are entered
109 /// and the iteration returns every BasicBlock. If the Flat mode is not
110 /// selected for SubRegions just one RegionNode containing the subregion is
111 /// returned.
112 template <class GraphType>
113 class FlatIt {};
114 
115 /// @brief A RegionNode represents a subregion or a BasicBlock that is part of a
116 /// Region.
117 template <class Tr>
119  friend class RegionBase<Tr>;
120 
121 public:
122  using BlockT = typename Tr::BlockT;
123  using RegionT = typename Tr::RegionT;
124 
125 private:
126  /// This is the entry basic block that starts this region node. If this is a
127  /// BasicBlock RegionNode, then entry is just the basic block, that this
128  /// RegionNode represents. Otherwise it is the entry of this (Sub)RegionNode.
129  ///
130  /// In the BBtoRegionNode map of the parent of this node, BB will always map
131  /// to this node no matter which kind of node this one is.
132  ///
133  /// The node can hold either a Region or a BasicBlock.
134  /// Use one bit to save, if this RegionNode is a subregion or BasicBlock
135  /// RegionNode.
137 
138  /// @brief The parent Region of this RegionNode.
139  /// @see getParent()
140  RegionT *parent;
141 
142 protected:
143  /// @brief Create a RegionNode.
144  ///
145  /// @param Parent The parent of this RegionNode.
146  /// @param Entry The entry BasicBlock of the RegionNode. If this
147  /// RegionNode represents a BasicBlock, this is the
148  /// BasicBlock itself. If it represents a subregion, this
149  /// is the entry BasicBlock of the subregion.
150  /// @param isSubRegion If this RegionNode represents a SubRegion.
151  inline RegionNodeBase(RegionT *Parent, BlockT *Entry,
152  bool isSubRegion = false)
153  : entry(Entry, isSubRegion), parent(Parent) {}
154 
155 public:
156  RegionNodeBase(const RegionNodeBase &) = delete;
157  RegionNodeBase &operator=(const RegionNodeBase &) = delete;
158 
159  /// @brief Get the parent Region of this RegionNode.
160  ///
161  /// The parent Region is the Region this RegionNode belongs to. If for
162  /// example a BasicBlock is element of two Regions, there exist two
163  /// RegionNodes for this BasicBlock. Each with the getParent() function
164  /// pointing to the Region this RegionNode belongs to.
165  ///
166  /// @return Get the parent Region of this RegionNode.
167  inline RegionT *getParent() const { return parent; }
168 
169  /// @brief Get the entry BasicBlock of this RegionNode.
170  ///
171  /// If this RegionNode represents a BasicBlock this is just the BasicBlock
172  /// itself, otherwise we return the entry BasicBlock of the Subregion
173  ///
174  /// @return The entry BasicBlock of this RegionNode.
175  inline BlockT *getEntry() const { return entry.getPointer(); }
176 
177  /// @brief Get the content of this RegionNode.
178  ///
179  /// This can be either a BasicBlock or a subregion. Before calling getNodeAs()
180  /// check the type of the content with the isSubRegion() function call.
181  ///
182  /// @return The content of this RegionNode.
183  template <class T> inline T *getNodeAs() const;
184 
185  /// @brief Is this RegionNode a subregion?
186  ///
187  /// @return True if it contains a subregion. False if it contains a
188  /// BasicBlock.
189  inline bool isSubRegion() const { return entry.getInt(); }
190 };
191 
192 //===----------------------------------------------------------------------===//
193 /// @brief A single entry single exit Region.
194 ///
195 /// A Region is a connected subgraph of a control flow graph that has exactly
196 /// two connections to the remaining graph. It can be used to analyze or
197 /// optimize parts of the control flow graph.
198 ///
199 /// A <em> simple Region </em> is connected to the remaining graph by just two
200 /// edges. One edge entering the Region and another one leaving the Region.
201 ///
202 /// An <em> extended Region </em> (or just Region) is a subgraph that can be
203 /// transform into a simple Region. The transformation is done by adding
204 /// BasicBlocks that merge several entry or exit edges so that after the merge
205 /// just one entry and one exit edge exists.
206 ///
207 /// The \e Entry of a Region is the first BasicBlock that is passed after
208 /// entering the Region. It is an element of the Region. The entry BasicBlock
209 /// dominates all BasicBlocks in the Region.
210 ///
211 /// The \e Exit of a Region is the first BasicBlock that is passed after
212 /// leaving the Region. It is not an element of the Region. The exit BasicBlock,
213 /// postdominates all BasicBlocks in the Region.
214 ///
215 /// A <em> canonical Region </em> cannot be constructed by combining smaller
216 /// Regions.
217 ///
218 /// Region A is the \e parent of Region B, if B is completely contained in A.
219 ///
220 /// Two canonical Regions either do not intersect at all or one is
221 /// the parent of the other.
222 ///
223 /// The <em> Program Structure Tree</em> is a graph (V, E) where V is the set of
224 /// Regions in the control flow graph and E is the \e parent relation of these
225 /// Regions.
226 ///
227 /// Example:
228 ///
229 /// \verbatim
230 /// A simple control flow graph, that contains two regions.
231 ///
232 /// 1
233 /// / |
234 /// 2 |
235 /// / \ 3
236 /// 4 5 |
237 /// | | |
238 /// 6 7 8
239 /// \ | /
240 /// \ |/ Region A: 1 -> 9 {1,2,3,4,5,6,7,8}
241 /// 9 Region B: 2 -> 9 {2,4,5,6,7}
242 /// \endverbatim
243 ///
244 /// You can obtain more examples by either calling
245 ///
246 /// <tt> "opt -regions -analyze anyprogram.ll" </tt>
247 /// or
248 /// <tt> "opt -view-regions-only anyprogram.ll" </tt>
249 ///
250 /// on any LLVM file you are interested in.
251 ///
252 /// The first call returns a textual representation of the program structure
253 /// tree, the second one creates a graphical representation using graphviz.
254 template <class Tr>
255 class RegionBase : public RegionNodeBase<Tr> {
256  friend class RegionInfoBase<Tr>;
257 
258  using FuncT = typename Tr::FuncT;
259  using BlockT = typename Tr::BlockT;
260  using RegionInfoT = typename Tr::RegionInfoT;
261  using RegionT = typename Tr::RegionT;
262  using RegionNodeT = typename Tr::RegionNodeT;
263  using DomTreeT = typename Tr::DomTreeT;
264  using LoopT = typename Tr::LoopT;
265  using LoopInfoT = typename Tr::LoopInfoT;
266  using InstT = typename Tr::InstT;
267 
270  using SuccIterTy = typename BlockTraits::ChildIteratorType;
271  using PredIterTy = typename InvBlockTraits::ChildIteratorType;
272 
273  // Information necessary to manage this Region.
274  RegionInfoT *RI;
275  DomTreeT *DT;
276 
277  // The exit BasicBlock of this region.
278  // (The entry BasicBlock is part of RegionNode)
279  BlockT *exit;
280 
281  using RegionSet = std::vector<std::unique_ptr<RegionT>>;
282 
283  // The subregions of this region.
284  RegionSet children;
285 
286  using BBNodeMapT = std::map<BlockT *, std::unique_ptr<RegionNodeT>>;
287 
288  // Save the BasicBlock RegionNodes that are element of this Region.
289  mutable BBNodeMapT BBNodeMap;
290 
291  /// Check if a BB is in this Region. This check also works
292  /// if the region is incorrectly built. (EXPENSIVE!)
293  void verifyBBInRegion(BlockT *BB) const;
294 
295  /// Walk over all the BBs of the region starting from BB and
296  /// verify that all reachable basic blocks are elements of the region.
297  /// (EXPENSIVE!)
298  void verifyWalk(BlockT *BB, std::set<BlockT *> *visitedBB) const;
299 
300  /// Verify if the region and its children are valid regions (EXPENSIVE!)
301  void verifyRegionNest() const;
302 
303 public:
304  /// @brief Create a new region.
305  ///
306  /// @param Entry The entry basic block of the region.
307  /// @param Exit The exit basic block of the region.
308  /// @param RI The region info object that is managing this region.
309  /// @param DT The dominator tree of the current function.
310  /// @param Parent The surrounding region or NULL if this is a top level
311  /// region.
312  RegionBase(BlockT *Entry, BlockT *Exit, RegionInfoT *RI, DomTreeT *DT,
313  RegionT *Parent = nullptr);
314 
315  RegionBase(const RegionBase &) = delete;
316  RegionBase &operator=(const RegionBase &) = delete;
317 
318  /// Delete the Region and all its subregions.
319  ~RegionBase();
320 
321  /// @brief Get the entry BasicBlock of the Region.
322  /// @return The entry BasicBlock of the region.
323  BlockT *getEntry() const {
325  }
326 
327  /// @brief Replace the entry basic block of the region with the new basic
328  /// block.
329  ///
330  /// @param BB The new entry basic block of the region.
331  void replaceEntry(BlockT *BB);
332 
333  /// @brief Replace the exit basic block of the region with the new basic
334  /// block.
335  ///
336  /// @param BB The new exit basic block of the region.
337  void replaceExit(BlockT *BB);
338 
339  /// @brief Recursively replace the entry basic block of the region.
340  ///
341  /// This function replaces the entry basic block with a new basic block. It
342  /// also updates all child regions that have the same entry basic block as
343  /// this region.
344  ///
345  /// @param NewEntry The new entry basic block.
346  void replaceEntryRecursive(BlockT *NewEntry);
347 
348  /// @brief Recursively replace the exit basic block of the region.
349  ///
350  /// This function replaces the exit basic block with a new basic block. It
351  /// also updates all child regions that have the same exit basic block as
352  /// this region.
353  ///
354  /// @param NewExit The new exit basic block.
355  void replaceExitRecursive(BlockT *NewExit);
356 
357  /// @brief Get the exit BasicBlock of the Region.
358  /// @return The exit BasicBlock of the Region, NULL if this is the TopLevel
359  /// Region.
360  BlockT *getExit() const { return exit; }
361 
362  /// @brief Get the parent of the Region.
363  /// @return The parent of the Region or NULL if this is a top level
364  /// Region.
365  RegionT *getParent() const {
367  }
368 
369  /// @brief Get the RegionNode representing the current Region.
370  /// @return The RegionNode representing the current Region.
371  RegionNodeT *getNode() const {
372  return const_cast<RegionNodeT *>(
373  reinterpret_cast<const RegionNodeT *>(this));
374  }
375 
376  /// @brief Get the nesting level of this Region.
377  ///
378  /// An toplevel Region has depth 0.
379  ///
380  /// @return The depth of the region.
381  unsigned getDepth() const;
382 
383  /// @brief Check if a Region is the TopLevel region.
384  ///
385  /// The toplevel region represents the whole function.
386  bool isTopLevelRegion() const { return exit == nullptr; }
387 
388  /// @brief Return a new (non-canonical) region, that is obtained by joining
389  /// this region with its predecessors.
390  ///
391  /// @return A region also starting at getEntry(), but reaching to the next
392  /// basic block that forms with getEntry() a (non-canonical) region.
393  /// NULL if such a basic block does not exist.
394  RegionT *getExpandedRegion() const;
395 
396  /// @brief Return the first block of this region's single entry edge,
397  /// if existing.
398  ///
399  /// @return The BasicBlock starting this region's single entry edge,
400  /// else NULL.
401  BlockT *getEnteringBlock() const;
402 
403  /// @brief Return the first block of this region's single exit edge,
404  /// if existing.
405  ///
406  /// @return The BasicBlock starting this region's single exit edge,
407  /// else NULL.
408  BlockT *getExitingBlock() const;
409 
410  /// @brief Is this a simple region?
411  ///
412  /// A region is simple if it has exactly one exit and one entry edge.
413  ///
414  /// @return True if the Region is simple.
415  bool isSimple() const;
416 
417  /// @brief Returns the name of the Region.
418  /// @return The Name of the Region.
419  std::string getNameStr() const;
420 
421  /// @brief Return the RegionInfo object, that belongs to this Region.
422  RegionInfoT *getRegionInfo() const { return RI; }
423 
424  /// PrintStyle - Print region in difference ways.
425  enum PrintStyle { PrintNone, PrintBB, PrintRN };
426 
427  /// @brief Print the region.
428  ///
429  /// @param OS The output stream the Region is printed to.
430  /// @param printTree Print also the tree of subregions.
431  /// @param level The indentation level used for printing.
432  void print(raw_ostream &OS, bool printTree = true, unsigned level = 0,
433  PrintStyle Style = PrintNone) const;
434 
435 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
436  /// @brief Print the region to stderr.
437  void dump() const;
438 #endif
439 
440  /// @brief Check if the region contains a BasicBlock.
441  ///
442  /// @param BB The BasicBlock that might be contained in this Region.
443  /// @return True if the block is contained in the region otherwise false.
444  bool contains(const BlockT *BB) const;
445 
446  /// @brief Check if the region contains another region.
447  ///
448  /// @param SubRegion The region that might be contained in this Region.
449  /// @return True if SubRegion is contained in the region otherwise false.
450  bool contains(const RegionT *SubRegion) const {
451  // Toplevel Region.
452  if (!getExit())
453  return true;
454 
455  return contains(SubRegion->getEntry()) &&
456  (contains(SubRegion->getExit()) ||
457  SubRegion->getExit() == getExit());
458  }
459 
460  /// @brief Check if the region contains an Instruction.
461  ///
462  /// @param Inst The Instruction that might be contained in this region.
463  /// @return True if the Instruction is contained in the region otherwise
464  /// false.
465  bool contains(const InstT *Inst) const { return contains(Inst->getParent()); }
466 
467  /// @brief Check if the region contains a loop.
468  ///
469  /// @param L The loop that might be contained in this region.
470  /// @return True if the loop is contained in the region otherwise false.
471  /// In case a NULL pointer is passed to this function the result
472  /// is false, except for the region that describes the whole function.
473  /// In that case true is returned.
474  bool contains(const LoopT *L) const;
475 
476  /// @brief Get the outermost loop in the region that contains a loop.
477  ///
478  /// Find for a Loop L the outermost loop OuterL that is a parent loop of L
479  /// and is itself contained in the region.
480  ///
481  /// @param L The loop the lookup is started.
482  /// @return The outermost loop in the region, NULL if such a loop does not
483  /// exist or if the region describes the whole function.
484  LoopT *outermostLoopInRegion(LoopT *L) const;
485 
486  /// @brief Get the outermost loop in the region that contains a basic block.
487  ///
488  /// Find for a basic block BB the outermost loop L that contains BB and is
489  /// itself contained in the region.
490  ///
491  /// @param LI A pointer to a LoopInfo analysis.
492  /// @param BB The basic block surrounded by the loop.
493  /// @return The outermost loop in the region, NULL if such a loop does not
494  /// exist or if the region describes the whole function.
495  LoopT *outermostLoopInRegion(LoopInfoT *LI, BlockT *BB) const;
496 
497  /// @brief Get the subregion that starts at a BasicBlock
498  ///
499  /// @param BB The BasicBlock the subregion should start.
500  /// @return The Subregion if available, otherwise NULL.
501  RegionT *getSubRegionNode(BlockT *BB) const;
502 
503  /// @brief Get the RegionNode for a BasicBlock
504  ///
505  /// @param BB The BasicBlock at which the RegionNode should start.
506  /// @return If available, the RegionNode that represents the subregion
507  /// starting at BB. If no subregion starts at BB, the RegionNode
508  /// representing BB.
509  RegionNodeT *getNode(BlockT *BB) const;
510 
511  /// @brief Get the BasicBlock RegionNode for a BasicBlock
512  ///
513  /// @param BB The BasicBlock for which the RegionNode is requested.
514  /// @return The RegionNode representing the BB.
515  RegionNodeT *getBBNode(BlockT *BB) const;
516 
517  /// @brief Add a new subregion to this Region.
518  ///
519  /// @param SubRegion The new subregion that will be added.
520  /// @param moveChildren Move the children of this region, that are also
521  /// contained in SubRegion into SubRegion.
522  void addSubRegion(RegionT *SubRegion, bool moveChildren = false);
523 
524  /// @brief Remove a subregion from this Region.
525  ///
526  /// The subregion is not deleted, as it will probably be inserted into another
527  /// region.
528  /// @param SubRegion The SubRegion that will be removed.
529  RegionT *removeSubRegion(RegionT *SubRegion);
530 
531  /// @brief Move all direct child nodes of this Region to another Region.
532  ///
533  /// @param To The Region the child nodes will be transferred to.
534  void transferChildrenTo(RegionT *To);
535 
536  /// @brief Verify if the region is a correct region.
537  ///
538  /// Check if this is a correctly build Region. This is an expensive check, as
539  /// the complete CFG of the Region will be walked.
540  void verifyRegion() const;
541 
542  /// @brief Clear the cache for BB RegionNodes.
543  ///
544  /// After calling this function the BasicBlock RegionNodes will be stored at
545  /// different memory locations. RegionNodes obtained before this function is
546  /// called are therefore not comparable to RegionNodes abtained afterwords.
547  void clearNodeCache();
548 
549  /// @name Subregion Iterators
550  ///
551  /// These iterators iterator over all subregions of this Region.
552  //@{
553  using iterator = typename RegionSet::iterator;
554  using const_iterator = typename RegionSet::const_iterator;
555 
556  iterator begin() { return children.begin(); }
557  iterator end() { return children.end(); }
558 
559  const_iterator begin() const { return children.begin(); }
560  const_iterator end() const { return children.end(); }
561  //@}
562 
563  /// @name BasicBlock Iterators
564  ///
565  /// These iterators iterate over all BasicBlocks that are contained in this
566  /// Region. The iterator also iterates over BasicBlocks that are elements of
567  /// a subregion of this Region. It is therefore called a flat iterator.
568  //@{
569  template <bool IsConst>
571  : public df_iterator<
572  typename std::conditional<IsConst, const BlockT, BlockT>::type *> {
573  using super =
574  df_iterator<
575  typename std::conditional<IsConst, const BlockT, BlockT>::type *>;
576 
577  public:
579  using value_type = typename super::value_type;
580 
581  // Construct the begin iterator.
583  : super(df_begin(Entry)) {
584  // Mark the exit of the region as visited, so that the children of the
585  // exit and the exit itself, i.e. the block outside the region will never
586  // be visited.
587  super::Visited.insert(Exit);
588  }
589 
590  // Construct the end iterator.
592 
593  /*implicit*/ block_iterator_wrapper(super I) : super(I) {}
594 
595  // FIXME: Even a const_iterator returns a non-const BasicBlock pointer.
596  // This was introduced for backwards compatibility, but should
597  // be removed as soon as all users are fixed.
598  BlockT *operator*() const {
599  return const_cast<BlockT *>(super::operator*());
600  }
601  };
602 
603  using block_iterator = block_iterator_wrapper<false>;
604  using const_block_iterator = block_iterator_wrapper<true>;
605 
606  block_iterator block_begin() { return block_iterator(getEntry(), getExit()); }
607 
609 
611  return const_block_iterator(getEntry(), getExit());
612  }
614 
617 
618  /// @brief Returns a range view of the basic blocks in the region.
619  inline block_range blocks() {
620  return block_range(block_begin(), block_end());
621  }
622 
623  /// @brief Returns a range view of the basic blocks in the region.
624  ///
625  /// This is the 'const' version of the range view.
626  inline const_block_range blocks() const {
627  return const_block_range(block_begin(), block_end());
628  }
629  //@}
630 
631  /// @name Element Iterators
632  ///
633  /// These iterators iterate over all BasicBlock and subregion RegionNodes that
634  /// are direct children of this Region. It does not iterate over any
635  /// RegionNodes that are also element of a subregion of this Region.
636  //@{
637  using element_iterator =
640 
641  using const_element_iterator =
642  df_iterator<const RegionNodeT *,
645 
646  element_iterator element_begin();
647  element_iterator element_end();
649  return make_range(element_begin(), element_end());
650  }
651 
652  const_element_iterator element_begin() const;
653  const_element_iterator element_end() const;
655  return make_range(element_begin(), element_end());
656  }
657  //@}
658 };
659 
660 /// Print a RegionNode.
661 template <class Tr>
662 inline raw_ostream &operator<<(raw_ostream &OS, const RegionNodeBase<Tr> &Node);
663 
664 //===----------------------------------------------------------------------===//
665 /// @brief Analysis that detects all canonical Regions.
666 ///
667 /// The RegionInfo pass detects all canonical regions in a function. The Regions
668 /// are connected using the parent relation. This builds a Program Structure
669 /// Tree.
670 template <class Tr>
671 class RegionInfoBase {
672  friend class RegionInfo;
673  friend class MachineRegionInfo;
674 
675  using BlockT = typename Tr::BlockT;
676  using FuncT = typename Tr::FuncT;
677  using RegionT = typename Tr::RegionT;
678  using RegionInfoT = typename Tr::RegionInfoT;
679  using DomTreeT = typename Tr::DomTreeT;
680  using DomTreeNodeT = typename Tr::DomTreeNodeT;
681  using PostDomTreeT = typename Tr::PostDomTreeT;
682  using DomFrontierT = typename Tr::DomFrontierT;
685  using SuccIterTy = typename BlockTraits::ChildIteratorType;
686  using PredIterTy = typename InvBlockTraits::ChildIteratorType;
687 
690 
691  RegionInfoBase();
692 
694  : DT(std::move(Arg.DT)), PDT(std::move(Arg.PDT)), DF(std::move(Arg.DF)),
695  TopLevelRegion(std::move(Arg.TopLevelRegion)),
696  BBtoRegion(std::move(Arg.BBtoRegion)) {
697  Arg.wipe();
698  }
699 
700  RegionInfoBase &operator=(RegionInfoBase &&RHS) {
701  DT = std::move(RHS.DT);
702  PDT = std::move(RHS.PDT);
703  DF = std::move(RHS.DF);
704  TopLevelRegion = std::move(RHS.TopLevelRegion);
705  BBtoRegion = std::move(RHS.BBtoRegion);
706  RHS.wipe();
707  return *this;
708  }
709 
710  virtual ~RegionInfoBase();
711 
712  DomTreeT *DT;
713  PostDomTreeT *PDT;
714  DomFrontierT *DF;
715 
716  /// The top level region.
717  RegionT *TopLevelRegion = nullptr;
718 
719  /// Map every BB to the smallest region, that contains BB.
720  BBtoRegionMap BBtoRegion;
721 
722 protected:
723  /// \brief Update refences to a RegionInfoT held by the RegionT managed here
724  ///
725  /// This is a post-move helper. Regions hold references to the owning
726  /// RegionInfo object. After a move these need to be fixed.
727  template<typename TheRegionT>
728  void updateRegionTree(RegionInfoT &RI, TheRegionT *R) {
729  if (!R)
730  return;
731  R->RI = &RI;
732  for (auto &SubR : *R)
733  updateRegionTree(RI, SubR.get());
734  }
735 
736 private:
737  /// \brief Wipe this region tree's state without releasing any resources.
738  ///
739  /// This is essentially a post-move helper only. It leaves the object in an
740  /// assignable and destroyable state, but otherwise invalid.
741  void wipe() {
742  DT = nullptr;
743  PDT = nullptr;
744  DF = nullptr;
745  TopLevelRegion = nullptr;
746  BBtoRegion.clear();
747  }
748 
749  // Check whether the entries of BBtoRegion for the BBs of region
750  // SR are correct. Triggers an assertion if not. Calls itself recursively for
751  // subregions.
752  void verifyBBMap(const RegionT *SR) const;
753 
754  // Returns true if BB is in the dominance frontier of
755  // entry, because it was inherited from exit. In the other case there is an
756  // edge going from entry to BB without passing exit.
757  bool isCommonDomFrontier(BlockT *BB, BlockT *entry, BlockT *exit) const;
758 
759  // Check if entry and exit surround a valid region, based on
760  // dominance tree and dominance frontier.
761  bool isRegion(BlockT *entry, BlockT *exit) const;
762 
763  // Saves a shortcut pointing from entry to exit.
764  // This function may extend this shortcut if possible.
765  void insertShortCut(BlockT *entry, BlockT *exit, BBtoBBMap *ShortCut) const;
766 
767  // Returns the next BB that postdominates N, while skipping
768  // all post dominators that cannot finish a canonical region.
769  DomTreeNodeT *getNextPostDom(DomTreeNodeT *N, BBtoBBMap *ShortCut) const;
770 
771  // A region is trivial, if it contains only one BB.
772  bool isTrivialRegion(BlockT *entry, BlockT *exit) const;
773 
774  // Creates a single entry single exit region.
775  RegionT *createRegion(BlockT *entry, BlockT *exit);
776 
777  // Detect all regions starting with bb 'entry'.
778  void findRegionsWithEntry(BlockT *entry, BBtoBBMap *ShortCut);
779 
780  // Detects regions in F.
781  void scanForRegions(FuncT &F, BBtoBBMap *ShortCut);
782 
783  // Get the top most parent with the same entry block.
784  RegionT *getTopMostParent(RegionT *region);
785 
786  // Build the region hierarchy after all region detected.
787  void buildRegionsTree(DomTreeNodeT *N, RegionT *region);
788 
789  // Update statistic about created regions.
790  virtual void updateStatistics(RegionT *R) = 0;
791 
792  // Detect all regions in function and build the region tree.
793  void calculate(FuncT &F);
794 
795 public:
796  RegionInfoBase(const RegionInfoBase &) = delete;
797  RegionInfoBase &operator=(const RegionInfoBase &) = delete;
798 
799  static bool VerifyRegionInfo;
800  static typename RegionT::PrintStyle printStyle;
801 
802  void print(raw_ostream &OS) const;
803 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
804  void dump() const;
805 #endif
806 
807  void releaseMemory();
808 
809  /// @brief Get the smallest region that contains a BasicBlock.
810  ///
811  /// @param BB The basic block.
812  /// @return The smallest region, that contains BB or NULL, if there is no
813  /// region containing BB.
814  RegionT *getRegionFor(BlockT *BB) const;
815 
816  /// @brief Set the smallest region that surrounds a basic block.
817  ///
818  /// @param BB The basic block surrounded by a region.
819  /// @param R The smallest region that surrounds BB.
820  void setRegionFor(BlockT *BB, RegionT *R);
821 
822  /// @brief A shortcut for getRegionFor().
823  ///
824  /// @param BB The basic block.
825  /// @return The smallest region, that contains BB or NULL, if there is no
826  /// region containing BB.
827  RegionT *operator[](BlockT *BB) const;
828 
829  /// @brief Return the exit of the maximal refined region, that starts at a
830  /// BasicBlock.
831  ///
832  /// @param BB The BasicBlock the refined region starts.
833  BlockT *getMaxRegionExit(BlockT *BB) const;
834 
835  /// @brief Find the smallest region that contains two regions.
836  ///
837  /// @param A The first region.
838  /// @param B The second region.
839  /// @return The smallest region containing A and B.
840  RegionT *getCommonRegion(RegionT *A, RegionT *B) const;
841 
842  /// @brief Find the smallest region that contains two basic blocks.
843  ///
844  /// @param A The first basic block.
845  /// @param B The second basic block.
846  /// @return The smallest region that contains A and B.
847  RegionT *getCommonRegion(BlockT *A, BlockT *B) const {
848  return getCommonRegion(getRegionFor(A), getRegionFor(B));
849  }
850 
851  /// @brief Find the smallest region that contains a set of regions.
852  ///
853  /// @param Regions A vector of regions.
854  /// @return The smallest region that contains all regions in Regions.
855  RegionT *getCommonRegion(SmallVectorImpl<RegionT *> &Regions) const;
856 
857  /// @brief Find the smallest region that contains a set of basic blocks.
858  ///
859  /// @param BBs A vector of basic blocks.
860  /// @return The smallest region that contains all basic blocks in BBS.
861  RegionT *getCommonRegion(SmallVectorImpl<BlockT *> &BBs) const;
862 
863  RegionT *getTopLevelRegion() const { return TopLevelRegion; }
864 
865  /// @brief Clear the Node Cache for all Regions.
866  ///
867  /// @see Region::clearNodeCache()
868  void clearNodeCache() {
869  if (TopLevelRegion)
870  TopLevelRegion->clearNodeCache();
871  }
872 
873  void verifyAnalysis() const;
874 };
875 
876 class Region;
877 
878 class RegionNode : public RegionNodeBase<RegionTraits<Function>> {
879 public:
880  inline RegionNode(Region *Parent, BasicBlock *Entry, bool isSubRegion = false)
881  : RegionNodeBase<RegionTraits<Function>>(Parent, Entry, isSubRegion) {}
882 
883  bool operator==(const Region &RN) const {
884  return this == reinterpret_cast<const RegionNode *>(&RN);
885  }
886 };
887 
888 class Region : public RegionBase<RegionTraits<Function>> {
889 public:
890  Region(BasicBlock *Entry, BasicBlock *Exit, RegionInfo *RI, DominatorTree *DT,
891  Region *Parent = nullptr);
892  ~Region();
893 
894  bool operator==(const RegionNode &RN) const {
895  return &RN == reinterpret_cast<const RegionNode *>(this);
896  }
897 };
898 
899 class RegionInfo : public RegionInfoBase<RegionTraits<Function>> {
900 public:
902 
903  explicit RegionInfo();
904 
905  RegionInfo(RegionInfo &&Arg) : Base(std::move(static_cast<Base &>(Arg))) {
906  updateRegionTree(*this, TopLevelRegion);
907  }
908 
910  Base::operator=(std::move(static_cast<Base &>(RHS)));
911  updateRegionTree(*this, TopLevelRegion);
912  return *this;
913  }
914 
915  ~RegionInfo() override;
916 
917  /// Handle invalidation explicitly.
918  bool invalidate(Function &F, const PreservedAnalyses &PA,
920 
921  // updateStatistics - Update statistic about created regions.
922  void updateStatistics(Region *R) final;
923 
924  void recalculate(Function &F, DominatorTree *DT, PostDominatorTree *PDT,
925  DominanceFrontier *DF);
926 
927 #ifndef NDEBUG
928  /// @brief Opens a viewer to show the GraphViz visualization of the regions.
929  ///
930  /// Useful during debugging as an alternative to dump().
931  void view();
932 
933  /// @brief Opens a viewer to show the GraphViz visualization of this region
934  /// without instructions in the BasicBlocks.
935  ///
936  /// Useful during debugging as an alternative to dump().
937  void viewOnly();
938 #endif
939 };
940 
941 class RegionInfoPass : public FunctionPass {
942  RegionInfo RI;
943 
944 public:
945  static char ID;
946 
947  explicit RegionInfoPass();
948  ~RegionInfoPass() override;
949 
950  RegionInfo &getRegionInfo() { return RI; }
951 
952  const RegionInfo &getRegionInfo() const { return RI; }
953 
954  /// @name FunctionPass interface
955  //@{
956  bool runOnFunction(Function &F) override;
957  void releaseMemory() override;
958  void verifyAnalysis() const override;
959  void getAnalysisUsage(AnalysisUsage &AU) const override;
960  void print(raw_ostream &OS, const Module *) const override;
961  void dump() const;
962  //@}
963 };
964 
965 /// \brief Analysis pass that exposes the \c RegionInfo for a function.
966 class RegionInfoAnalysis : public AnalysisInfoMixin<RegionInfoAnalysis> {
968 
969  static AnalysisKey Key;
970 
971 public:
973 
975 };
976 
977 /// \brief Printer pass for the \c RegionInfo.
978 class RegionInfoPrinterPass : public PassInfoMixin<RegionInfoPrinterPass> {
979  raw_ostream &OS;
980 
981 public:
982  explicit RegionInfoPrinterPass(raw_ostream &OS);
983 
985 };
986 
987 /// \brief Verifier pass for the \c RegionInfo.
988 struct RegionInfoVerifierPass : PassInfoMixin<RegionInfoVerifierPass> {
990 };
991 
992 template <>
993 template <>
994 inline BasicBlock *
995 RegionNodeBase<RegionTraits<Function>>::getNodeAs<BasicBlock>() const {
996  assert(!isSubRegion() && "This is not a BasicBlock RegionNode!");
997  return getEntry();
998 }
999 
1000 template <>
1001 template <>
1002 inline Region *
1003 RegionNodeBase<RegionTraits<Function>>::getNodeAs<Region>() const {
1004  assert(isSubRegion() && "This is not a subregion RegionNode!");
1005  auto Unconst = const_cast<RegionNodeBase<RegionTraits<Function>> *>(this);
1006  return reinterpret_cast<Region *>(Unconst);
1007 }
1008 
1009 template <class Tr>
1011  const RegionNodeBase<Tr> &Node) {
1012  using BlockT = typename Tr::BlockT;
1013  using RegionT = typename Tr::RegionT;
1014 
1015  if (Node.isSubRegion())
1016  return OS << Node.template getNodeAs<RegionT>()->getNameStr();
1017  else
1018  return OS << Node.template getNodeAs<BlockT>()->getName();
1019 }
1020 
1021 extern template class RegionBase<RegionTraits<Function>>;
1022 extern template class RegionNodeBase<RegionTraits<Function>>;
1023 extern template class RegionInfoBase<RegionTraits<Function>>;
1024 
1025 } // end namespace llvm
1026 
1027 #endif // LLVM_ANALYSIS_REGIONINFO_H
iterator_range< typename GraphTraits< GraphType >::ChildIteratorType > children(const typename GraphTraits< GraphType >::NodeRef &G)
Definition: GraphTraits.h:102
bool contains(const InstT *Inst) const
Check if the region contains an Instruction.
Definition: RegionInfo.h:465
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
PointerTy getPointer() const
Various leaf nodes.
Definition: ISDOpcodes.h:60
block_iterator block_begin()
Definition: RegionInfo.h:606
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:63
static RegionT::PrintStyle printStyle
Definition: RegionInfo.h:800
This provides a very simple, boring adaptor for a begin and end iterator into a range type...
block_iterator_wrapper< true > const_block_iterator
Definition: RegionInfo.h:604
RegionNodeBase(RegionT *Parent, BlockT *Entry, bool isSubRegion=false)
Create a RegionNode.
Definition: RegionInfo.h:151
RegionInfo & operator=(RegionInfo &&RHS)
Definition: RegionInfo.h:909
RegionT * getCommonRegion(BlockT *A, BlockT *B) const
Find the smallest region that contains two basic blocks.
Definition: RegionInfo.h:847
typename super::value_type value_type
Definition: RegionInfo.h:579
BlockT * getExit() const
Get the exit BasicBlock of the Region.
Definition: RegionInfo.h:360
bool isSubRegion() const
Is this RegionNode a subregion?
Definition: RegionInfo.h:189
Analysis that detects all canonical Regions.
Definition: RegionInfo.h:69
const_block_iterator block_end() const
Definition: RegionInfo.h:613
return AArch64::GPR64RegClass contains(Reg)
bool contains(const RegionT *SubRegion) const
Check if the region contains another region.
Definition: RegionInfo.h:450
Definition: BitVector.h:920
RegionNodeT * getNode() const
Get the RegionNode representing the current Region.
Definition: RegionInfo.h:371
A RegionNode represents a subregion or a BasicBlock that is part of a Region.
Definition: RegionInfo.h:118
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:42
iterator end()
Definition: RegionInfo.h:557
static StringRef getName(Value *V)
RegionInfo & getRegionInfo()
Definition: RegionInfo.h:950
APInt operator*(APInt a, uint64_t RHS)
Definition: APInt.h:2070
PrintStyle
PrintStyle - Print region in difference ways.
Definition: RegionInfo.h:425
static bool isSimple(Instruction *I)
RegionT * getTopLevelRegion() const
Definition: RegionInfo.h:863
RegionT * getParent() const
Get the parent Region of this RegionNode.
Definition: RegionInfo.h:167
block_range blocks()
Returns a range view of the basic blocks in the region.
Definition: RegionInfo.h:619
bool operator==(const RegionNode &RN) const
Definition: RegionInfo.h:894
#define F(x, y, z)
Definition: MD5.cpp:55
BlockT * getEntry() const
Get the entry BasicBlock of this RegionNode.
Definition: RegionInfo.h:175
IntType getInt() const
A CRTP mix-in to automatically provide informational APIs needed for passes.
Definition: PassManager.h:365
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree...
Definition: Dominators.h:134
Verifier pass for the RegionInfo.
Definition: RegionInfo.h:988
void dump(const SparseBitVector< ElementSize > &LHS, raw_ostream &out)
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:153
LLVM Basic Block Representation.
Definition: BasicBlock.h:59
df_iterator< T > df_end(const T &G)
block_iterator_wrapper(value_type Entry, value_type Exit)
Definition: RegionInfo.h:582
#define A
Definition: LargeTest.cpp:12
A CRTP mix-in that provides informational APIs needed for analysis passes.
Definition: PassManager.h:382
typename RegionTraits< Function > ::BlockT BlockT
Definition: RegionInfo.h:122
Represent the analysis usage information of a pass.
void updateRegionTree(RegionInfoT &RI, TheRegionT *R)
Update refences to a RegionInfoT held by the RegionT managed here.
Definition: RegionInfo.h:728
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:298
bool operator==(const Region &RN) const
Definition: RegionInfo.h:883
typename RegionSet::iterator iterator
Definition: RegionInfo.h:553
bool isTopLevelRegion() const
Check if a Region is the TopLevel region.
Definition: RegionInfo.h:386
typename RegionSet::const_iterator const_iterator
Definition: RegionInfo.h:554
iterator begin()
Definition: RegionInfo.h:556
iterator_range< T > make_range(T x, T y)
Convenience function for iterating over sub-ranges.
RegionInfo(RegionInfo &&Arg)
Definition: RegionInfo.h:905
const_block_iterator block_begin() const
Definition: RegionInfo.h:610
#define B
Definition: LargeTest.cpp:24
BlockT * getEntry() const
Get the entry BasicBlock of the Region.
Definition: RegionInfo.h:323
block_iterator block_end()
Definition: RegionInfo.h:608
const size_t N
RegionInfoT * getRegionInfo() const
Return the RegionInfo object, that belongs to this Region.
Definition: RegionInfo.h:422
A single entry single exit Region.
Definition: RegionInfo.h:67
Analysis pass that exposes the RegionInfo for a function.
Definition: RegionInfo.h:966
iterator_range< const_element_iterator > elements() const
Definition: RegionInfo.h:654
df_iterator< T > df_begin(const T &G)
A range adaptor for a pair of iterators.
const_block_range blocks() const
Returns a range view of the basic blocks in the region.
Definition: RegionInfo.h:626
PostDominatorTree Class - Concrete subclass of DominatorTree that is used to compute the post-dominat...
const_iterator end() const
Definition: RegionInfo.h:560
Represents a single loop in the control flow graph.
Definition: LoopInfo.h:360
#define I(x, y, z)
Definition: MD5.cpp:58
const_iterator begin() const
Definition: RegionInfo.h:559
const RegionInfo & getRegionInfo() const
Definition: RegionInfo.h:952
RegionNode(Region *Parent, BasicBlock *Entry, bool isSubRegion=false)
Definition: RegionInfo.h:880
typename FuncT_::UnknownRegionTypeError BrokenT
Definition: RegionInfo.h:82
block_iterator_wrapper< false > block_iterator
Definition: RegionInfo.h:603
Marker class to iterate over the elements of a Region in flat mode.
Definition: RegionInfo.h:113
raw_ostream & operator<<(raw_ostream &OS, const APInt &I)
Definition: APInt.h:2018
API to communicate dependencies between analyses during invalidation.
Definition: PassManager.h:559
RegionT * getParent() const
Get the parent of the Region.
Definition: RegionInfo.h:365
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
unsigned getNumSuccessors() const
Return the number of successors that this terminator has.
DomTreeNodeBase< BasicBlock > DomTreeNode
Definition: Dominators.h:64
void clearNodeCache()
Clear the Node Cache for all Regions.
Definition: RegionInfo.h:868
static bool VerifyRegionInfo
Definition: RegionInfo.h:799
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:44
A container for analyses that lazily runs them and caches their results.
const TerminatorInst * getTerminator() const LLVM_READONLY
Returns the terminator instruction if the block is well formed or null if the block is not well forme...
Definition: BasicBlock.cpp:120
This header defines various interfaces for pass management in LLVM.
iterator_range< element_iterator > elements()
Definition: RegionInfo.h:648
Printer pass for the RegionInfo.
Definition: RegionInfo.h:978
A special type used by analysis passes to provide an address that identifies that particular analysis...
Definition: PassManager.h:70
static unsigned getNumSuccessors(BasicBlock *BB)
Definition: RegionInfo.h:100