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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/Config/llvm-config.h"
46 #include "llvm/IR/BasicBlock.h"
47 #include "llvm/IR/Dominators.h"
48 #include "llvm/IR/PassManager.h"
49 #include "llvm/Pass.h"
51 #include <algorithm>
52 #include <cassert>
53 #include <map>
54 #include <memory>
55 #include <set>
56 #include <string>
57 #include <type_traits>
58 #include <vector>
59 
60 namespace llvm {
61 
62 class DominanceFrontier;
63 class DominatorTree;
64 class Loop;
65 class LoopInfo;
66 class PostDominatorTree;
67 class Region;
68 template <class RegionTr> class RegionBase;
69 class RegionInfo;
70 template <class RegionTr> class RegionInfoBase;
71 class RegionNode;
72 
73 // Class to be specialized for different users of RegionInfo
74 // (i.e. BasicBlocks or MachineBasicBlocks). This is only to avoid needing to
75 // pass around an unreasonable number of template parameters.
76 template <class FuncT_>
77 struct RegionTraits {
78  // FuncT
79  // BlockT
80  // RegionT
81  // RegionNodeT
82  // RegionInfoT
83  using BrokenT = typename FuncT_::UnknownRegionTypeError;
84 };
85 
86 template <>
88  using FuncT = Function;
89  using BlockT = BasicBlock;
90  using RegionT = Region;
97  using InstT = Instruction;
98  using LoopT = Loop;
100 
101  static unsigned getNumSuccessors(BasicBlock *BB) {
102  return BB->getTerminator()->getNumSuccessors();
103  }
104 };
105 
106 /// Marker class to iterate over the elements of a Region in flat mode.
107 ///
108 /// The class is used to either iterate in Flat mode or by not using it to not
109 /// iterate in Flat mode. During a Flat mode iteration all Regions are entered
110 /// and the iteration returns every BasicBlock. If the Flat mode is not
111 /// selected for SubRegions just one RegionNode containing the subregion is
112 /// returned.
113 template <class GraphType>
114 class FlatIt {};
115 
116 /// A RegionNode represents a subregion or a BasicBlock that is part of a
117 /// Region.
118 template <class Tr>
120  friend class RegionBase<Tr>;
121 
122 public:
123  using BlockT = typename Tr::BlockT;
124  using RegionT = typename Tr::RegionT;
125 
126 private:
127  /// This is the entry basic block that starts this region node. If this is a
128  /// BasicBlock RegionNode, then entry is just the basic block, that this
129  /// RegionNode represents. Otherwise it is the entry of this (Sub)RegionNode.
130  ///
131  /// In the BBtoRegionNode map of the parent of this node, BB will always map
132  /// to this node no matter which kind of node this one is.
133  ///
134  /// The node can hold either a Region or a BasicBlock.
135  /// Use one bit to save, if this RegionNode is a subregion or BasicBlock
136  /// RegionNode.
138 
139  /// The parent Region of this RegionNode.
140  /// @see getParent()
141  RegionT *parent;
142 
143 protected:
144  /// Create a RegionNode.
145  ///
146  /// @param Parent The parent of this RegionNode.
147  /// @param Entry The entry BasicBlock of the RegionNode. If this
148  /// RegionNode represents a BasicBlock, this is the
149  /// BasicBlock itself. If it represents a subregion, this
150  /// is the entry BasicBlock of the subregion.
151  /// @param isSubRegion If this RegionNode represents a SubRegion.
152  inline RegionNodeBase(RegionT *Parent, BlockT *Entry,
153  bool isSubRegion = false)
154  : entry(Entry, isSubRegion), parent(Parent) {}
155 
156 public:
157  RegionNodeBase(const RegionNodeBase &) = delete;
158  RegionNodeBase &operator=(const RegionNodeBase &) = delete;
159 
160  /// Get the parent Region of this RegionNode.
161  ///
162  /// The parent Region is the Region this RegionNode belongs to. If for
163  /// example a BasicBlock is element of two Regions, there exist two
164  /// RegionNodes for this BasicBlock. Each with the getParent() function
165  /// pointing to the Region this RegionNode belongs to.
166  ///
167  /// @return Get the parent Region of this RegionNode.
168  inline RegionT *getParent() const { return parent; }
169 
170  /// Get the entry BasicBlock of this RegionNode.
171  ///
172  /// If this RegionNode represents a BasicBlock this is just the BasicBlock
173  /// itself, otherwise we return the entry BasicBlock of the Subregion
174  ///
175  /// @return The entry BasicBlock of this RegionNode.
176  inline BlockT *getEntry() const { return entry.getPointer(); }
177 
178  /// Get the content of this RegionNode.
179  ///
180  /// This can be either a BasicBlock or a subregion. Before calling getNodeAs()
181  /// check the type of the content with the isSubRegion() function call.
182  ///
183  /// @return The content of this RegionNode.
184  template <class T> inline T *getNodeAs() const;
185 
186  /// Is this RegionNode a subregion?
187  ///
188  /// @return True if it contains a subregion. False if it contains a
189  /// BasicBlock.
190  inline bool isSubRegion() const { return entry.getInt(); }
191 };
192 
193 //===----------------------------------------------------------------------===//
194 /// A single entry single exit Region.
195 ///
196 /// A Region is a connected subgraph of a control flow graph that has exactly
197 /// two connections to the remaining graph. It can be used to analyze or
198 /// optimize parts of the control flow graph.
199 ///
200 /// A <em> simple Region </em> is connected to the remaining graph by just two
201 /// edges. One edge entering the Region and another one leaving the Region.
202 ///
203 /// An <em> extended Region </em> (or just Region) is a subgraph that can be
204 /// transform into a simple Region. The transformation is done by adding
205 /// BasicBlocks that merge several entry or exit edges so that after the merge
206 /// just one entry and one exit edge exists.
207 ///
208 /// The \e Entry of a Region is the first BasicBlock that is passed after
209 /// entering the Region. It is an element of the Region. The entry BasicBlock
210 /// dominates all BasicBlocks in the Region.
211 ///
212 /// The \e Exit of a Region is the first BasicBlock that is passed after
213 /// leaving the Region. It is not an element of the Region. The exit BasicBlock,
214 /// postdominates all BasicBlocks in the Region.
215 ///
216 /// A <em> canonical Region </em> cannot be constructed by combining smaller
217 /// Regions.
218 ///
219 /// Region A is the \e parent of Region B, if B is completely contained in A.
220 ///
221 /// Two canonical Regions either do not intersect at all or one is
222 /// the parent of the other.
223 ///
224 /// The <em> Program Structure Tree</em> is a graph (V, E) where V is the set of
225 /// Regions in the control flow graph and E is the \e parent relation of these
226 /// Regions.
227 ///
228 /// Example:
229 ///
230 /// \verbatim
231 /// A simple control flow graph, that contains two regions.
232 ///
233 /// 1
234 /// / |
235 /// 2 |
236 /// / \ 3
237 /// 4 5 |
238 /// | | |
239 /// 6 7 8
240 /// \ | /
241 /// \ |/ Region A: 1 -> 9 {1,2,3,4,5,6,7,8}
242 /// 9 Region B: 2 -> 9 {2,4,5,6,7}
243 /// \endverbatim
244 ///
245 /// You can obtain more examples by either calling
246 ///
247 /// <tt> "opt -regions -analyze anyprogram.ll" </tt>
248 /// or
249 /// <tt> "opt -view-regions-only anyprogram.ll" </tt>
250 ///
251 /// on any LLVM file you are interested in.
252 ///
253 /// The first call returns a textual representation of the program structure
254 /// tree, the second one creates a graphical representation using graphviz.
255 template <class Tr>
256 class RegionBase : public RegionNodeBase<Tr> {
257  friend class RegionInfoBase<Tr>;
258 
259  using FuncT = typename Tr::FuncT;
260  using BlockT = typename Tr::BlockT;
261  using RegionInfoT = typename Tr::RegionInfoT;
262  using RegionT = typename Tr::RegionT;
263  using RegionNodeT = typename Tr::RegionNodeT;
264  using DomTreeT = typename Tr::DomTreeT;
265  using LoopT = typename Tr::LoopT;
266  using LoopInfoT = typename Tr::LoopInfoT;
267  using InstT = typename Tr::InstT;
268 
271  using SuccIterTy = typename BlockTraits::ChildIteratorType;
272  using PredIterTy = typename InvBlockTraits::ChildIteratorType;
273 
274  // Information necessary to manage this Region.
275  RegionInfoT *RI;
276  DomTreeT *DT;
277 
278  // The exit BasicBlock of this region.
279  // (The entry BasicBlock is part of RegionNode)
280  BlockT *exit;
281 
282  using RegionSet = std::vector<std::unique_ptr<RegionT>>;
283 
284  // The subregions of this region.
285  RegionSet children;
286 
287  using BBNodeMapT = std::map<BlockT *, std::unique_ptr<RegionNodeT>>;
288 
289  // Save the BasicBlock RegionNodes that are element of this Region.
290  mutable BBNodeMapT BBNodeMap;
291 
292  /// Check if a BB is in this Region. This check also works
293  /// if the region is incorrectly built. (EXPENSIVE!)
294  void verifyBBInRegion(BlockT *BB) const;
295 
296  /// Walk over all the BBs of the region starting from BB and
297  /// verify that all reachable basic blocks are elements of the region.
298  /// (EXPENSIVE!)
299  void verifyWalk(BlockT *BB, std::set<BlockT *> *visitedBB) const;
300 
301  /// Verify if the region and its children are valid regions (EXPENSIVE!)
302  void verifyRegionNest() const;
303 
304 public:
305  /// Create a new region.
306  ///
307  /// @param Entry The entry basic block of the region.
308  /// @param Exit The exit basic block of the region.
309  /// @param RI The region info object that is managing this region.
310  /// @param DT The dominator tree of the current function.
311  /// @param Parent The surrounding region or NULL if this is a top level
312  /// region.
313  RegionBase(BlockT *Entry, BlockT *Exit, RegionInfoT *RI, DomTreeT *DT,
314  RegionT *Parent = nullptr);
315 
316  RegionBase(const RegionBase &) = delete;
317  RegionBase &operator=(const RegionBase &) = delete;
318 
319  /// Delete the Region and all its subregions.
320  ~RegionBase();
321 
322  /// Get the entry BasicBlock of the Region.
323  /// @return The entry BasicBlock of the region.
324  BlockT *getEntry() const {
326  }
327 
328  /// Replace the entry basic block of the region with the new basic
329  /// block.
330  ///
331  /// @param BB The new entry basic block of the region.
332  void replaceEntry(BlockT *BB);
333 
334  /// Replace the exit basic block of the region with the new basic
335  /// block.
336  ///
337  /// @param BB The new exit basic block of the region.
338  void replaceExit(BlockT *BB);
339 
340  /// Recursively replace the entry basic block of the region.
341  ///
342  /// This function replaces the entry basic block with a new basic block. It
343  /// also updates all child regions that have the same entry basic block as
344  /// this region.
345  ///
346  /// @param NewEntry The new entry basic block.
347  void replaceEntryRecursive(BlockT *NewEntry);
348 
349  /// Recursively replace the exit basic block of the region.
350  ///
351  /// This function replaces the exit basic block with a new basic block. It
352  /// also updates all child regions that have the same exit basic block as
353  /// this region.
354  ///
355  /// @param NewExit The new exit basic block.
356  void replaceExitRecursive(BlockT *NewExit);
357 
358  /// Get the exit BasicBlock of the Region.
359  /// @return The exit BasicBlock of the Region, NULL if this is the TopLevel
360  /// Region.
361  BlockT *getExit() const { return exit; }
362 
363  /// Get the parent of the Region.
364  /// @return The parent of the Region or NULL if this is a top level
365  /// Region.
366  RegionT *getParent() const {
368  }
369 
370  /// Get the RegionNode representing the current Region.
371  /// @return The RegionNode representing the current Region.
372  RegionNodeT *getNode() const {
373  return const_cast<RegionNodeT *>(
374  reinterpret_cast<const RegionNodeT *>(this));
375  }
376 
377  /// Get the nesting level of this Region.
378  ///
379  /// An toplevel Region has depth 0.
380  ///
381  /// @return The depth of the region.
382  unsigned getDepth() const;
383 
384  /// Check if a Region is the TopLevel region.
385  ///
386  /// The toplevel region represents the whole function.
387  bool isTopLevelRegion() const { return exit == nullptr; }
388 
389  /// Return a new (non-canonical) region, that is obtained by joining
390  /// this region with its predecessors.
391  ///
392  /// @return A region also starting at getEntry(), but reaching to the next
393  /// basic block that forms with getEntry() a (non-canonical) region.
394  /// NULL if such a basic block does not exist.
395  RegionT *getExpandedRegion() const;
396 
397  /// Return the first block of this region's single entry edge,
398  /// if existing.
399  ///
400  /// @return The BasicBlock starting this region's single entry edge,
401  /// else NULL.
402  BlockT *getEnteringBlock() const;
403 
404  /// Return the first block of this region's single exit edge,
405  /// if existing.
406  ///
407  /// @return The BasicBlock starting this region's single exit edge,
408  /// else NULL.
409  BlockT *getExitingBlock() const;
410 
411  /// Collect all blocks of this region's single exit edge, if existing.
412  ///
413  /// @return True if this region contains all the predecessors of the exit.
414  bool getExitingBlocks(SmallVectorImpl<BlockT *> &Exitings) const;
415 
416  /// Is this a simple region?
417  ///
418  /// A region is simple if it has exactly one exit and one entry edge.
419  ///
420  /// @return True if the Region is simple.
421  bool isSimple() const;
422 
423  /// Returns the name of the Region.
424  /// @return The Name of the Region.
425  std::string getNameStr() const;
426 
427  /// Return the RegionInfo object, that belongs to this Region.
428  RegionInfoT *getRegionInfo() const { return RI; }
429 
430  /// PrintStyle - Print region in difference ways.
431  enum PrintStyle { PrintNone, PrintBB, PrintRN };
432 
433  /// Print the region.
434  ///
435  /// @param OS The output stream the Region is printed to.
436  /// @param printTree Print also the tree of subregions.
437  /// @param level The indentation level used for printing.
438  void print(raw_ostream &OS, bool printTree = true, unsigned level = 0,
439  PrintStyle Style = PrintNone) const;
440 
441 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
442  /// Print the region to stderr.
443  void dump() const;
444 #endif
445 
446  /// Check if the region contains a BasicBlock.
447  ///
448  /// @param BB The BasicBlock that might be contained in this Region.
449  /// @return True if the block is contained in the region otherwise false.
450  bool contains(const BlockT *BB) const;
451 
452  /// Check if the region contains another region.
453  ///
454  /// @param SubRegion The region that might be contained in this Region.
455  /// @return True if SubRegion is contained in the region otherwise false.
456  bool contains(const RegionT *SubRegion) const {
457  // Toplevel Region.
458  if (!getExit())
459  return true;
460 
461  return contains(SubRegion->getEntry()) &&
462  (contains(SubRegion->getExit()) ||
463  SubRegion->getExit() == getExit());
464  }
465 
466  /// Check if the region contains an Instruction.
467  ///
468  /// @param Inst The Instruction that might be contained in this region.
469  /// @return True if the Instruction is contained in the region otherwise
470  /// false.
471  bool contains(const InstT *Inst) const { return contains(Inst->getParent()); }
472 
473  /// Check if the region contains a loop.
474  ///
475  /// @param L The loop that might be contained in this region.
476  /// @return True if the loop is contained in the region otherwise false.
477  /// In case a NULL pointer is passed to this function the result
478  /// is false, except for the region that describes the whole function.
479  /// In that case true is returned.
480  bool contains(const LoopT *L) const;
481 
482  /// Get the outermost loop in the region that contains a loop.
483  ///
484  /// Find for a Loop L the outermost loop OuterL that is a parent loop of L
485  /// and is itself contained in the region.
486  ///
487  /// @param L The loop the lookup is started.
488  /// @return The outermost loop in the region, NULL if such a loop does not
489  /// exist or if the region describes the whole function.
490  LoopT *outermostLoopInRegion(LoopT *L) const;
491 
492  /// Get the outermost loop in the region that contains a basic block.
493  ///
494  /// Find for a basic block BB the outermost loop L that contains BB and is
495  /// itself contained in the region.
496  ///
497  /// @param LI A pointer to a LoopInfo analysis.
498  /// @param BB The basic block surrounded by the loop.
499  /// @return The outermost loop in the region, NULL if such a loop does not
500  /// exist or if the region describes the whole function.
501  LoopT *outermostLoopInRegion(LoopInfoT *LI, BlockT *BB) const;
502 
503  /// Get the subregion that starts at a BasicBlock
504  ///
505  /// @param BB The BasicBlock the subregion should start.
506  /// @return The Subregion if available, otherwise NULL.
507  RegionT *getSubRegionNode(BlockT *BB) const;
508 
509  /// Get the RegionNode for a BasicBlock
510  ///
511  /// @param BB The BasicBlock at which the RegionNode should start.
512  /// @return If available, the RegionNode that represents the subregion
513  /// starting at BB. If no subregion starts at BB, the RegionNode
514  /// representing BB.
515  RegionNodeT *getNode(BlockT *BB) const;
516 
517  /// Get the BasicBlock RegionNode for a BasicBlock
518  ///
519  /// @param BB The BasicBlock for which the RegionNode is requested.
520  /// @return The RegionNode representing the BB.
521  RegionNodeT *getBBNode(BlockT *BB) const;
522 
523  /// Add a new subregion to this Region.
524  ///
525  /// @param SubRegion The new subregion that will be added.
526  /// @param moveChildren Move the children of this region, that are also
527  /// contained in SubRegion into SubRegion.
528  void addSubRegion(RegionT *SubRegion, bool moveChildren = false);
529 
530  /// Remove a subregion from this Region.
531  ///
532  /// The subregion is not deleted, as it will probably be inserted into another
533  /// region.
534  /// @param SubRegion The SubRegion that will be removed.
535  RegionT *removeSubRegion(RegionT *SubRegion);
536 
537  /// Move all direct child nodes of this Region to another Region.
538  ///
539  /// @param To The Region the child nodes will be transferred to.
540  void transferChildrenTo(RegionT *To);
541 
542  /// Verify if the region is a correct region.
543  ///
544  /// Check if this is a correctly build Region. This is an expensive check, as
545  /// the complete CFG of the Region will be walked.
546  void verifyRegion() const;
547 
548  /// Clear the cache for BB RegionNodes.
549  ///
550  /// After calling this function the BasicBlock RegionNodes will be stored at
551  /// different memory locations. RegionNodes obtained before this function is
552  /// called are therefore not comparable to RegionNodes abtained afterwords.
553  void clearNodeCache();
554 
555  /// @name Subregion Iterators
556  ///
557  /// These iterators iterator over all subregions of this Region.
558  //@{
559  using iterator = typename RegionSet::iterator;
560  using const_iterator = typename RegionSet::const_iterator;
561 
562  iterator begin() { return children.begin(); }
563  iterator end() { return children.end(); }
564 
565  const_iterator begin() const { return children.begin(); }
566  const_iterator end() const { return children.end(); }
567  //@}
568 
569  /// @name BasicBlock Iterators
570  ///
571  /// These iterators iterate over all BasicBlocks that are contained in this
572  /// Region. The iterator also iterates over BasicBlocks that are elements of
573  /// a subregion of this Region. It is therefore called a flat iterator.
574  //@{
575  template <bool IsConst>
577  : public df_iterator<
578  typename std::conditional<IsConst, const BlockT, BlockT>::type *> {
579  using super =
580  df_iterator<
581  typename std::conditional<IsConst, const BlockT, BlockT>::type *>;
582 
583  public:
585  using value_type = typename super::value_type;
586 
587  // Construct the begin iterator.
589  : super(df_begin(Entry)) {
590  // Mark the exit of the region as visited, so that the children of the
591  // exit and the exit itself, i.e. the block outside the region will never
592  // be visited.
593  super::Visited.insert(Exit);
594  }
595 
596  // Construct the end iterator.
598 
599  /*implicit*/ block_iterator_wrapper(super I) : super(I) {}
600 
601  // FIXME: Even a const_iterator returns a non-const BasicBlock pointer.
602  // This was introduced for backwards compatibility, but should
603  // be removed as soon as all users are fixed.
604  BlockT *operator*() const {
605  return const_cast<BlockT *>(super::operator*());
606  }
607  };
608 
609  using block_iterator = block_iterator_wrapper<false>;
610  using const_block_iterator = block_iterator_wrapper<true>;
611 
612  block_iterator block_begin() { return block_iterator(getEntry(), getExit()); }
613 
615 
617  return const_block_iterator(getEntry(), getExit());
618  }
620 
623 
624  /// Returns a range view of the basic blocks in the region.
625  inline block_range blocks() {
626  return block_range(block_begin(), block_end());
627  }
628 
629  /// Returns a range view of the basic blocks in the region.
630  ///
631  /// This is the 'const' version of the range view.
632  inline const_block_range blocks() const {
633  return const_block_range(block_begin(), block_end());
634  }
635  //@}
636 
637  /// @name Element Iterators
638  ///
639  /// These iterators iterate over all BasicBlock and subregion RegionNodes that
640  /// are direct children of this Region. It does not iterate over any
641  /// RegionNodes that are also element of a subregion of this Region.
642  //@{
643  using element_iterator =
646 
647  using const_element_iterator =
648  df_iterator<const RegionNodeT *,
651 
652  element_iterator element_begin();
653  element_iterator element_end();
655  return make_range(element_begin(), element_end());
656  }
657 
658  const_element_iterator element_begin() const;
659  const_element_iterator element_end() const;
661  return make_range(element_begin(), element_end());
662  }
663  //@}
664 };
665 
666 /// Print a RegionNode.
667 template <class Tr>
668 inline raw_ostream &operator<<(raw_ostream &OS, const RegionNodeBase<Tr> &Node);
669 
670 //===----------------------------------------------------------------------===//
671 /// Analysis that detects all canonical Regions.
672 ///
673 /// The RegionInfo pass detects all canonical regions in a function. The Regions
674 /// are connected using the parent relation. This builds a Program Structure
675 /// Tree.
676 template <class Tr>
677 class RegionInfoBase {
678  friend class RegionInfo;
679  friend class MachineRegionInfo;
680 
681  using BlockT = typename Tr::BlockT;
682  using FuncT = typename Tr::FuncT;
683  using RegionT = typename Tr::RegionT;
684  using RegionInfoT = typename Tr::RegionInfoT;
685  using DomTreeT = typename Tr::DomTreeT;
686  using DomTreeNodeT = typename Tr::DomTreeNodeT;
687  using PostDomTreeT = typename Tr::PostDomTreeT;
688  using DomFrontierT = typename Tr::DomFrontierT;
691  using SuccIterTy = typename BlockTraits::ChildIteratorType;
692  using PredIterTy = typename InvBlockTraits::ChildIteratorType;
693 
696 
697  RegionInfoBase();
698 
700  : DT(std::move(Arg.DT)), PDT(std::move(Arg.PDT)), DF(std::move(Arg.DF)),
701  TopLevelRegion(std::move(Arg.TopLevelRegion)),
702  BBtoRegion(std::move(Arg.BBtoRegion)) {
703  Arg.wipe();
704  }
705 
706  RegionInfoBase &operator=(RegionInfoBase &&RHS) {
707  DT = std::move(RHS.DT);
708  PDT = std::move(RHS.PDT);
709  DF = std::move(RHS.DF);
710  TopLevelRegion = std::move(RHS.TopLevelRegion);
711  BBtoRegion = std::move(RHS.BBtoRegion);
712  RHS.wipe();
713  return *this;
714  }
715 
716  virtual ~RegionInfoBase();
717 
718  DomTreeT *DT;
719  PostDomTreeT *PDT;
720  DomFrontierT *DF;
721 
722  /// The top level region.
723  RegionT *TopLevelRegion = nullptr;
724 
725  /// Map every BB to the smallest region, that contains BB.
726  BBtoRegionMap BBtoRegion;
727 
728 protected:
729  /// Update refences to a RegionInfoT held by the RegionT managed here
730  ///
731  /// This is a post-move helper. Regions hold references to the owning
732  /// RegionInfo object. After a move these need to be fixed.
733  template<typename TheRegionT>
734  void updateRegionTree(RegionInfoT &RI, TheRegionT *R) {
735  if (!R)
736  return;
737  R->RI = &RI;
738  for (auto &SubR : *R)
739  updateRegionTree(RI, SubR.get());
740  }
741 
742 private:
743  /// Wipe this region tree's state without releasing any resources.
744  ///
745  /// This is essentially a post-move helper only. It leaves the object in an
746  /// assignable and destroyable state, but otherwise invalid.
747  void wipe() {
748  DT = nullptr;
749  PDT = nullptr;
750  DF = nullptr;
751  TopLevelRegion = nullptr;
752  BBtoRegion.clear();
753  }
754 
755  // Check whether the entries of BBtoRegion for the BBs of region
756  // SR are correct. Triggers an assertion if not. Calls itself recursively for
757  // subregions.
758  void verifyBBMap(const RegionT *SR) const;
759 
760  // Returns true if BB is in the dominance frontier of
761  // entry, because it was inherited from exit. In the other case there is an
762  // edge going from entry to BB without passing exit.
763  bool isCommonDomFrontier(BlockT *BB, BlockT *entry, BlockT *exit) const;
764 
765  // Check if entry and exit surround a valid region, based on
766  // dominance tree and dominance frontier.
767  bool isRegion(BlockT *entry, BlockT *exit) const;
768 
769  // Saves a shortcut pointing from entry to exit.
770  // This function may extend this shortcut if possible.
771  void insertShortCut(BlockT *entry, BlockT *exit, BBtoBBMap *ShortCut) const;
772 
773  // Returns the next BB that postdominates N, while skipping
774  // all post dominators that cannot finish a canonical region.
775  DomTreeNodeT *getNextPostDom(DomTreeNodeT *N, BBtoBBMap *ShortCut) const;
776 
777  // A region is trivial, if it contains only one BB.
778  bool isTrivialRegion(BlockT *entry, BlockT *exit) const;
779 
780  // Creates a single entry single exit region.
781  RegionT *createRegion(BlockT *entry, BlockT *exit);
782 
783  // Detect all regions starting with bb 'entry'.
784  void findRegionsWithEntry(BlockT *entry, BBtoBBMap *ShortCut);
785 
786  // Detects regions in F.
787  void scanForRegions(FuncT &F, BBtoBBMap *ShortCut);
788 
789  // Get the top most parent with the same entry block.
790  RegionT *getTopMostParent(RegionT *region);
791 
792  // Build the region hierarchy after all region detected.
793  void buildRegionsTree(DomTreeNodeT *N, RegionT *region);
794 
795  // Update statistic about created regions.
796  virtual void updateStatistics(RegionT *R) = 0;
797 
798  // Detect all regions in function and build the region tree.
799  void calculate(FuncT &F);
800 
801 public:
802  RegionInfoBase(const RegionInfoBase &) = delete;
803  RegionInfoBase &operator=(const RegionInfoBase &) = delete;
804 
805  static bool VerifyRegionInfo;
806  static typename RegionT::PrintStyle printStyle;
807 
808  void print(raw_ostream &OS) const;
809 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
810  void dump() const;
811 #endif
812 
813  void releaseMemory();
814 
815  /// Get the smallest region that contains a BasicBlock.
816  ///
817  /// @param BB The basic block.
818  /// @return The smallest region, that contains BB or NULL, if there is no
819  /// region containing BB.
820  RegionT *getRegionFor(BlockT *BB) const;
821 
822  /// Set the smallest region that surrounds a basic block.
823  ///
824  /// @param BB The basic block surrounded by a region.
825  /// @param R The smallest region that surrounds BB.
826  void setRegionFor(BlockT *BB, RegionT *R);
827 
828  /// A shortcut for getRegionFor().
829  ///
830  /// @param BB The basic block.
831  /// @return The smallest region, that contains BB or NULL, if there is no
832  /// region containing BB.
833  RegionT *operator[](BlockT *BB) const;
834 
835  /// Return the exit of the maximal refined region, that starts at a
836  /// BasicBlock.
837  ///
838  /// @param BB The BasicBlock the refined region starts.
839  BlockT *getMaxRegionExit(BlockT *BB) const;
840 
841  /// Find the smallest region that contains two regions.
842  ///
843  /// @param A The first region.
844  /// @param B The second region.
845  /// @return The smallest region containing A and B.
846  RegionT *getCommonRegion(RegionT *A, RegionT *B) const;
847 
848  /// Find the smallest region that contains two basic blocks.
849  ///
850  /// @param A The first basic block.
851  /// @param B The second basic block.
852  /// @return The smallest region that contains A and B.
853  RegionT *getCommonRegion(BlockT *A, BlockT *B) const {
854  return getCommonRegion(getRegionFor(A), getRegionFor(B));
855  }
856 
857  /// Find the smallest region that contains a set of regions.
858  ///
859  /// @param Regions A vector of regions.
860  /// @return The smallest region that contains all regions in Regions.
861  RegionT *getCommonRegion(SmallVectorImpl<RegionT *> &Regions) const;
862 
863  /// Find the smallest region that contains a set of basic blocks.
864  ///
865  /// @param BBs A vector of basic blocks.
866  /// @return The smallest region that contains all basic blocks in BBS.
867  RegionT *getCommonRegion(SmallVectorImpl<BlockT *> &BBs) const;
868 
869  RegionT *getTopLevelRegion() const { return TopLevelRegion; }
870 
871  /// Clear the Node Cache for all Regions.
872  ///
873  /// @see Region::clearNodeCache()
874  void clearNodeCache() {
875  if (TopLevelRegion)
876  TopLevelRegion->clearNodeCache();
877  }
878 
879  void verifyAnalysis() const;
880 };
881 
882 class Region;
883 
884 class RegionNode : public RegionNodeBase<RegionTraits<Function>> {
885 public:
886  inline RegionNode(Region *Parent, BasicBlock *Entry, bool isSubRegion = false)
887  : RegionNodeBase<RegionTraits<Function>>(Parent, Entry, isSubRegion) {}
888 
889  bool operator==(const Region &RN) const {
890  return this == reinterpret_cast<const RegionNode *>(&RN);
891  }
892 };
893 
894 class Region : public RegionBase<RegionTraits<Function>> {
895 public:
896  Region(BasicBlock *Entry, BasicBlock *Exit, RegionInfo *RI, DominatorTree *DT,
897  Region *Parent = nullptr);
898  ~Region();
899 
900  bool operator==(const RegionNode &RN) const {
901  return &RN == reinterpret_cast<const RegionNode *>(this);
902  }
903 };
904 
905 class RegionInfo : public RegionInfoBase<RegionTraits<Function>> {
906 public:
908 
909  explicit RegionInfo();
910 
911  RegionInfo(RegionInfo &&Arg) : Base(std::move(static_cast<Base &>(Arg))) {
912  updateRegionTree(*this, TopLevelRegion);
913  }
914 
916  Base::operator=(std::move(static_cast<Base &>(RHS)));
917  updateRegionTree(*this, TopLevelRegion);
918  return *this;
919  }
920 
921  ~RegionInfo() override;
922 
923  /// Handle invalidation explicitly.
924  bool invalidate(Function &F, const PreservedAnalyses &PA,
926 
927  // updateStatistics - Update statistic about created regions.
928  void updateStatistics(Region *R) final;
929 
930  void recalculate(Function &F, DominatorTree *DT, PostDominatorTree *PDT,
931  DominanceFrontier *DF);
932 
933 #ifndef NDEBUG
934  /// Opens a viewer to show the GraphViz visualization of the regions.
935  ///
936  /// Useful during debugging as an alternative to dump().
937  void view();
938 
939  /// Opens a viewer to show the GraphViz visualization of this region
940  /// without instructions in the BasicBlocks.
941  ///
942  /// Useful during debugging as an alternative to dump().
943  void viewOnly();
944 #endif
945 };
946 
947 class RegionInfoPass : public FunctionPass {
948  RegionInfo RI;
949 
950 public:
951  static char ID;
952 
953  explicit RegionInfoPass();
954  ~RegionInfoPass() override;
955 
956  RegionInfo &getRegionInfo() { return RI; }
957 
958  const RegionInfo &getRegionInfo() const { return RI; }
959 
960  /// @name FunctionPass interface
961  //@{
962  bool runOnFunction(Function &F) override;
963  void releaseMemory() override;
964  void verifyAnalysis() const override;
965  void getAnalysisUsage(AnalysisUsage &AU) const override;
966  void print(raw_ostream &OS, const Module *) const override;
967  void dump() const;
968  //@}
969 };
970 
971 /// Analysis pass that exposes the \c RegionInfo for a function.
972 class RegionInfoAnalysis : public AnalysisInfoMixin<RegionInfoAnalysis> {
974 
975  static AnalysisKey Key;
976 
977 public:
979 
981 };
982 
983 /// Printer pass for the \c RegionInfo.
984 class RegionInfoPrinterPass : public PassInfoMixin<RegionInfoPrinterPass> {
985  raw_ostream &OS;
986 
987 public:
988  explicit RegionInfoPrinterPass(raw_ostream &OS);
989 
991 };
992 
993 /// Verifier pass for the \c RegionInfo.
994 struct RegionInfoVerifierPass : PassInfoMixin<RegionInfoVerifierPass> {
996 };
997 
998 template <>
999 template <>
1000 inline BasicBlock *
1001 RegionNodeBase<RegionTraits<Function>>::getNodeAs<BasicBlock>() const {
1002  assert(!isSubRegion() && "This is not a BasicBlock RegionNode!");
1003  return getEntry();
1004 }
1005 
1006 template <>
1007 template <>
1008 inline Region *
1009 RegionNodeBase<RegionTraits<Function>>::getNodeAs<Region>() const {
1010  assert(isSubRegion() && "This is not a subregion RegionNode!");
1011  auto Unconst = const_cast<RegionNodeBase<RegionTraits<Function>> *>(this);
1012  return reinterpret_cast<Region *>(Unconst);
1013 }
1014 
1015 template <class Tr>
1017  const RegionNodeBase<Tr> &Node) {
1018  using BlockT = typename Tr::BlockT;
1019  using RegionT = typename Tr::RegionT;
1020 
1021  if (Node.isSubRegion())
1022  return OS << Node.template getNodeAs<RegionT>()->getNameStr();
1023  else
1024  return OS << Node.template getNodeAs<BlockT>()->getName();
1025 }
1026 
1027 extern template class RegionBase<RegionTraits<Function>>;
1028 extern template class RegionNodeBase<RegionTraits<Function>>;
1029 extern template class RegionInfoBase<RegionTraits<Function>>;
1030 
1031 } // end namespace llvm
1032 
1033 #endif // LLVM_ANALYSIS_REGIONINFO_H
iterator_range< typename GraphTraits< GraphType >::ChildIteratorType > children(const typename GraphTraits< GraphType >::NodeRef &G)
Definition: GraphTraits.h:115
bool contains(const InstT *Inst) const
Check if the region contains an Instruction.
Definition: RegionInfo.h:471
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:612
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:806
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:610
RegionNodeBase(RegionT *Parent, BlockT *Entry, bool isSubRegion=false)
Create a RegionNode.
Definition: RegionInfo.h:152
RegionInfo & operator=(RegionInfo &&RHS)
Definition: RegionInfo.h:915
F(f)
RegionT * getCommonRegion(BlockT *A, BlockT *B) const
Find the smallest region that contains two basic blocks.
Definition: RegionInfo.h:853
typename super::value_type value_type
Definition: RegionInfo.h:585
BlockT * getExit() const
Get the exit BasicBlock of the Region.
Definition: RegionInfo.h:361
bool isSubRegion() const
Is this RegionNode a subregion?
Definition: RegionInfo.h:190
Analysis that detects all canonical Regions.
Definition: RegionInfo.h:70
const_block_iterator block_end() const
Definition: RegionInfo.h:619
return AArch64::GPR64RegClass contains(Reg)
static void verifyRegion(const VPRegionBlock *Region)
Verify the CFG invariants of VPRegionBlock Region and its nested VPBlockBases.
bool contains(const RegionT *SubRegion) const
Check if the region contains another region.
Definition: RegionInfo.h:456
Definition: BitVector.h:921
RegionNodeT * getNode() const
Get the RegionNode representing the current Region.
Definition: RegionInfo.h:372
A RegionNode represents a subregion or a BasicBlock that is part of a Region.
Definition: RegionInfo.h:119
iterator end()
Definition: RegionInfo.h:563
static StringRef getName(Value *V)
RegionInfo & getRegionInfo()
Definition: RegionInfo.h:956
APInt operator*(APInt a, uint64_t RHS)
Definition: APInt.h:2084
PrintStyle
PrintStyle - Print region in difference ways.
Definition: RegionInfo.h:431
static bool isSimple(Instruction *I)
RegionT * getTopLevelRegion() const
Definition: RegionInfo.h:869
Key
PAL metadata keys.
RegionT * getParent() const
Get the parent Region of this RegionNode.
Definition: RegionInfo.h:168
block_range blocks()
Returns a range view of the basic blocks in the region.
Definition: RegionInfo.h:625
bool operator==(const RegionNode &RN) const
Definition: RegionInfo.h:900
BlockT * getEntry() const
Get the entry BasicBlock of this RegionNode.
Definition: RegionInfo.h:176
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:142
static bool runOnFunction(Function &F, bool PostInlining)
Verifier pass for the RegionInfo.
Definition: RegionInfo.h:994
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
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:588
A CRTP mix-in that provides informational APIs needed for analysis passes.
Definition: PassManager.h:382
typename RegionTraits< Function > ::BlockT BlockT
Definition: RegionInfo.h:123
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:734
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:285
static void print(raw_ostream &Out, object::Archive::Kind Kind, T Val)
bool operator==(const Region &RN) const
Definition: RegionInfo.h:889
typename RegionSet::iterator iterator
Definition: RegionInfo.h:559
bool isTopLevelRegion() const
Check if a Region is the TopLevel region.
Definition: RegionInfo.h:387
typename RegionSet::const_iterator const_iterator
Definition: RegionInfo.h:560
iterator begin()
Definition: RegionInfo.h:562
iterator_range< T > make_range(T x, T y)
Convenience function for iterating over sub-ranges.
RegionInfo(RegionInfo &&Arg)
Definition: RegionInfo.h:911
const_block_iterator block_begin() const
Definition: RegionInfo.h:616
BlockT * getEntry() const
Get the entry BasicBlock of the Region.
Definition: RegionInfo.h:324
block_iterator block_end()
Definition: RegionInfo.h:614
RegionInfoT * getRegionInfo() const
Return the RegionInfo object, that belongs to this Region.
Definition: RegionInfo.h:428
A single entry single exit Region.
Definition: RegionInfo.h:68
Analysis pass that exposes the RegionInfo for a function.
Definition: RegionInfo.h:972
iterator_range< const_element_iterator > elements() const
Definition: RegionInfo.h:660
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:632
PostDominatorTree Class - Concrete subclass of DominatorTree that is used to compute the post-dominat...
amdgpu Simplify well known AMD library false Value Value * Arg
const_iterator end() const
Definition: RegionInfo.h:566
Represents a single loop in the control flow graph.
Definition: LoopInfo.h:459
#define I(x, y, z)
Definition: MD5.cpp:58
#define N
const_iterator begin() const
Definition: RegionInfo.h:565
static GCRegistry::Add< ErlangGC > A("erlang", "erlang-compatible garbage collector")
const RegionInfo & getRegionInfo() const
Definition: RegionInfo.h:958
RegionNode(Region *Parent, BasicBlock *Entry, bool isSubRegion=false)
Definition: RegionInfo.h:886
typename FuncT_::UnknownRegionTypeError BrokenT
Definition: RegionInfo.h:83
block_iterator_wrapper< false > block_iterator
Definition: RegionInfo.h:609
Marker class to iterate over the elements of a Region in flat mode.
Definition: RegionInfo.h:114
raw_ostream & operator<<(raw_ostream &OS, const APInt &I)
Definition: APInt.h:2032
API to communicate dependencies between analyses during invalidation.
Definition: PassManager.h:559
RegionT * getParent() const
Get the parent of the Region.
Definition: RegionInfo.h:366
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:72
void clearNodeCache()
Clear the Node Cache for all Regions.
Definition: RegionInfo.h:874
static bool VerifyRegionInfo
Definition: RegionInfo.h:805
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:46
print Instructions which execute on loop entry
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:138
This header defines various interfaces for pass management in LLVM.
iterator_range< element_iterator > elements()
Definition: RegionInfo.h:654
Printer pass for the RegionInfo.
Definition: RegionInfo.h:984
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:101