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/PointerIntPair.h" 41 #include "llvm/ADT/iterator_range.h" 42 #include "llvm/Analysis/DominanceFrontier.h" 43 #include "llvm/Analysis/PostDominators.h" 44 #include "llvm/Support/Allocator.h" 45 #include <map> 46 #include <memory> 47 48 namespace llvm { 49 50 class Region; 51 class RegionInfo; 52 class raw_ostream; 53 class Loop; 54 class LoopInfo; 55 56 /// @brief Marker class to iterate over the elements of a Region in flat mode. 57 /// 58 /// The class is used to either iterate in Flat mode or by not using it to not 59 /// iterate in Flat mode. During a Flat mode iteration all Regions are entered 60 /// and the iteration returns every BasicBlock. If the Flat mode is not 61 /// selected for SubRegions just one RegionNode containing the subregion is 62 /// returned. 63 template <class GraphType> 64 class FlatIt {}; 65 66 /// @brief A RegionNode represents a subregion or a BasicBlock that is part of a 67 /// Region. 68 class RegionNode { 69 RegionNode(const RegionNode &) LLVM_DELETED_FUNCTION; 70 const RegionNode &operator=(const RegionNode &) LLVM_DELETED_FUNCTION; 71 72 protected: 73 /// This is the entry basic block that starts this region node. If this is a 74 /// BasicBlock RegionNode, then entry is just the basic block, that this 75 /// RegionNode represents. Otherwise it is the entry of this (Sub)RegionNode. 76 /// 77 /// In the BBtoRegionNode map of the parent of this node, BB will always map 78 /// to this node no matter which kind of node this one is. 79 /// 80 /// The node can hold either a Region or a BasicBlock. 81 /// Use one bit to save, if this RegionNode is a subregion or BasicBlock 82 /// RegionNode. 83 PointerIntPair<BasicBlock*, 1, bool> entry; 84 85 /// @brief The parent Region of this RegionNode. 86 /// @see getParent() 87 Region* parent; 88 89 public: 90 /// @brief Create a RegionNode. 91 /// 92 /// @param Parent The parent of this RegionNode. 93 /// @param Entry The entry BasicBlock of the RegionNode. If this 94 /// RegionNode represents a BasicBlock, this is the 95 /// BasicBlock itself. If it represents a subregion, this 96 /// is the entry BasicBlock of the subregion. 97 /// @param isSubRegion If this RegionNode represents a SubRegion. 98 inline RegionNode(Region* Parent, BasicBlock* Entry, bool isSubRegion = 0) 99 : entry(Entry, isSubRegion), parent(Parent) {} 100 101 /// @brief Get the parent Region of this RegionNode. 102 /// 103 /// The parent Region is the Region this RegionNode belongs to. If for 104 /// example a BasicBlock is element of two Regions, there exist two 105 /// RegionNodes for this BasicBlock. Each with the getParent() function 106 /// pointing to the Region this RegionNode belongs to. 107 /// 108 /// @return Get the parent Region of this RegionNode. 109 inline Region* getParent() const { return parent; } 110 111 /// @brief Get the entry BasicBlock of this RegionNode. 112 /// 113 /// If this RegionNode represents a BasicBlock this is just the BasicBlock 114 /// itself, otherwise we return the entry BasicBlock of the Subregion 115 /// 116 /// @return The entry BasicBlock of this RegionNode. 117 inline BasicBlock* getEntry() const { return entry.getPointer(); } 118 119 /// @brief Get the content of this RegionNode. 120 /// 121 /// This can be either a BasicBlock or a subregion. Before calling getNodeAs() 122 /// check the type of the content with the isSubRegion() function call. 123 /// 124 /// @return The content of this RegionNode. 125 template<class T> 126 inline T* getNodeAs() const; 127 128 /// @brief Is this RegionNode a subregion? 129 /// 130 /// @return True if it contains a subregion. False if it contains a 131 /// BasicBlock. 132 inline bool isSubRegion() const { 133 return entry.getInt(); 134 } 135 }; 136 137 /// Print a RegionNode. 138 inline raw_ostream &operator<<(raw_ostream &OS, const RegionNode &Node); 139 140 template<> 141 inline BasicBlock* RegionNode::getNodeAs<BasicBlock>() const { 142 assert(!isSubRegion() && "This is not a BasicBlock RegionNode!"); 143 return getEntry(); 144 } 145 146 template<> 147 inline Region* RegionNode::getNodeAs<Region>() const { 148 assert(isSubRegion() && "This is not a subregion RegionNode!"); 149 return reinterpret_cast<Region*>(const_cast<RegionNode*>(this)); 150 } 151 152 //===----------------------------------------------------------------------===// 153 /// @brief A single entry single exit Region. 154 /// 155 /// A Region is a connected subgraph of a control flow graph that has exactly 156 /// two connections to the remaining graph. It can be used to analyze or 157 /// optimize parts of the control flow graph. 158 /// 159 /// A <em> simple Region </em> is connected to the remaining graph by just two 160 /// edges. One edge entering the Region and another one leaving the Region. 161 /// 162 /// An <em> extended Region </em> (or just Region) is a subgraph that can be 163 /// transform into a simple Region. The transformation is done by adding 164 /// BasicBlocks that merge several entry or exit edges so that after the merge 165 /// just one entry and one exit edge exists. 166 /// 167 /// The \e Entry of a Region is the first BasicBlock that is passed after 168 /// entering the Region. It is an element of the Region. The entry BasicBlock 169 /// dominates all BasicBlocks in the Region. 170 /// 171 /// The \e Exit of a Region is the first BasicBlock that is passed after 172 /// leaving the Region. It is not an element of the Region. The exit BasicBlock, 173 /// postdominates all BasicBlocks in the Region. 174 /// 175 /// A <em> canonical Region </em> cannot be constructed by combining smaller 176 /// Regions. 177 /// 178 /// Region A is the \e parent of Region B, if B is completely contained in A. 179 /// 180 /// Two canonical Regions either do not intersect at all or one is 181 /// the parent of the other. 182 /// 183 /// The <em> Program Structure Tree</em> is a graph (V, E) where V is the set of 184 /// Regions in the control flow graph and E is the \e parent relation of these 185 /// Regions. 186 /// 187 /// Example: 188 /// 189 /// \verbatim 190 /// A simple control flow graph, that contains two regions. 191 /// 192 /// 1 193 /// / | 194 /// 2 | 195 /// / \ 3 196 /// 4 5 | 197 /// | | | 198 /// 6 7 8 199 /// \ | / 200 /// \ |/ Region A: 1 -> 9 {1,2,3,4,5,6,7,8} 201 /// 9 Region B: 2 -> 9 {2,4,5,6,7} 202 /// \endverbatim 203 /// 204 /// You can obtain more examples by either calling 205 /// 206 /// <tt> "opt -regions -analyze anyprogram.ll" </tt> 207 /// or 208 /// <tt> "opt -view-regions-only anyprogram.ll" </tt> 209 /// 210 /// on any LLVM file you are interested in. 211 /// 212 /// The first call returns a textual representation of the program structure 213 /// tree, the second one creates a graphical representation using graphviz. 214 class Region : public RegionNode { 215 friend class RegionInfo; 216 Region(const Region &) LLVM_DELETED_FUNCTION; 217 const Region &operator=(const Region &) LLVM_DELETED_FUNCTION; 218 219 // Information necessary to manage this Region. 220 RegionInfo* RI; 221 DominatorTree *DT; 222 223 // The exit BasicBlock of this region. 224 // (The entry BasicBlock is part of RegionNode) 225 BasicBlock *exit; 226 227 typedef std::vector<std::unique_ptr<Region>> RegionSet; 228 229 // The subregions of this region. 230 RegionSet children; 231 232 typedef std::map<BasicBlock*, RegionNode*> BBNodeMapT; 233 234 // Save the BasicBlock RegionNodes that are element of this Region. 235 mutable BBNodeMapT BBNodeMap; 236 237 /// verifyBBInRegion - Check if a BB is in this Region. This check also works 238 /// if the region is incorrectly built. (EXPENSIVE!) 239 void verifyBBInRegion(BasicBlock* BB) const; 240 241 /// verifyWalk - Walk over all the BBs of the region starting from BB and 242 /// verify that all reachable basic blocks are elements of the region. 243 /// (EXPENSIVE!) 244 void verifyWalk(BasicBlock* BB, std::set<BasicBlock*>* visitedBB) const; 245 246 /// verifyRegionNest - Verify if the region and its children are valid 247 /// regions (EXPENSIVE!) 248 void verifyRegionNest() const; 249 250 public: 251 /// @brief Create a new region. 252 /// 253 /// @param Entry The entry basic block of the region. 254 /// @param Exit The exit basic block of the region. 255 /// @param RI The region info object that is managing this region. 256 /// @param DT The dominator tree of the current function. 257 /// @param Parent The surrounding region or NULL if this is a top level 258 /// region. 259 Region(BasicBlock *Entry, BasicBlock *Exit, RegionInfo* RI, 260 DominatorTree *DT, Region *Parent = nullptr); 261 262 /// Delete the Region and all its subregions. 263 ~Region(); 264 265 /// @brief Get the entry BasicBlock of the Region. 266 /// @return The entry BasicBlock of the region. 267 BasicBlock *getEntry() const { return RegionNode::getEntry(); } 268 269 /// @brief Replace the entry basic block of the region with the new basic 270 /// block. 271 /// 272 /// @param BB The new entry basic block of the region. 273 void replaceEntry(BasicBlock *BB); 274 275 /// @brief Replace the exit basic block of the region with the new basic 276 /// block. 277 /// 278 /// @param BB The new exit basic block of the region. 279 void replaceExit(BasicBlock *BB); 280 281 /// @brief Recursively replace the entry basic block of the region. 282 /// 283 /// This function replaces the entry basic block with a new basic block. It 284 /// also updates all child regions that have the same entry basic block as 285 /// this region. 286 /// 287 /// @param NewEntry The new entry basic block. 288 void replaceEntryRecursive(BasicBlock *NewEntry); 289 290 /// @brief Recursively replace the exit basic block of the region. 291 /// 292 /// This function replaces the exit basic block with a new basic block. It 293 /// also updates all child regions that have the same exit basic block as 294 /// this region. 295 /// 296 /// @param NewExit The new exit basic block. 297 void replaceExitRecursive(BasicBlock *NewExit); 298 299 /// @brief Get the exit BasicBlock of the Region. 300 /// @return The exit BasicBlock of the Region, NULL if this is the TopLevel 301 /// Region. 302 BasicBlock *getExit() const { return exit; } 303 304 /// @brief Get the parent of the Region. 305 /// @return The parent of the Region or NULL if this is a top level 306 /// Region. 307 Region *getParent() const { return RegionNode::getParent(); } 308 309 /// @brief Get the RegionNode representing the current Region. 310 /// @return The RegionNode representing the current Region. 311 RegionNode* getNode() const { 312 return const_cast<RegionNode*>(reinterpret_cast<const RegionNode*>(this)); 313 } 314 315 /// @brief Get the nesting level of this Region. 316 /// 317 /// An toplevel Region has depth 0. 318 /// 319 /// @return The depth of the region. 320 unsigned getDepth() const; 321 322 /// @brief Check if a Region is the TopLevel region. 323 /// 324 /// The toplevel region represents the whole function. 325 bool isTopLevelRegion() const { return exit == nullptr; } 326 327 /// @brief Return a new (non-canonical) region, that is obtained by joining 328 /// this region with its predecessors. 329 /// 330 /// @return A region also starting at getEntry(), but reaching to the next 331 /// basic block that forms with getEntry() a (non-canonical) region. 332 /// NULL if such a basic block does not exist. 333 Region *getExpandedRegion() const; 334 335 /// @brief Return the first block of this region's single entry edge, 336 /// if existing. 337 /// 338 /// @return The BasicBlock starting this region's single entry edge, 339 /// else NULL. 340 BasicBlock *getEnteringBlock() const; 341 342 /// @brief Return the first block of this region's single exit edge, 343 /// if existing. 344 /// 345 /// @return The BasicBlock starting this region's single exit edge, 346 /// else NULL. 347 BasicBlock *getExitingBlock() const; 348 349 /// @brief Is this a simple region? 350 /// 351 /// A region is simple if it has exactly one exit and one entry edge. 352 /// 353 /// @return True if the Region is simple. 354 bool isSimple() const; 355 356 /// @brief Returns the name of the Region. 357 /// @return The Name of the Region. 358 std::string getNameStr() const; 359 360 /// @brief Return the RegionInfo object, that belongs to this Region. 361 RegionInfo *getRegionInfo() const { 362 return RI; 363 } 364 365 /// PrintStyle - Print region in difference ways. 366 enum PrintStyle { PrintNone, PrintBB, PrintRN }; 367 368 /// @brief Print the region. 369 /// 370 /// @param OS The output stream the Region is printed to. 371 /// @param printTree Print also the tree of subregions. 372 /// @param level The indentation level used for printing. 373 void print(raw_ostream& OS, bool printTree = true, unsigned level = 0, 374 enum PrintStyle Style = PrintNone) const; 375 376 /// @brief Print the region to stderr. 377 void dump() const; 378 379 /// @brief Check if the region contains a BasicBlock. 380 /// 381 /// @param BB The BasicBlock that might be contained in this Region. 382 /// @return True if the block is contained in the region otherwise false. 383 bool contains(const BasicBlock *BB) const; 384 385 /// @brief Check if the region contains another region. 386 /// 387 /// @param SubRegion The region that might be contained in this Region. 388 /// @return True if SubRegion is contained in the region otherwise false. 389 bool contains(const Region *SubRegion) const { 390 // Toplevel Region. 391 if (!getExit()) 392 return true; 393 394 return contains(SubRegion->getEntry()) 395 && (contains(SubRegion->getExit()) || SubRegion->getExit() == getExit()); 396 } 397 398 /// @brief Check if the region contains an Instruction. 399 /// 400 /// @param Inst The Instruction that might be contained in this region. 401 /// @return True if the Instruction is contained in the region otherwise false. 402 bool contains(const Instruction *Inst) const { 403 return contains(Inst->getParent()); 404 } 405 406 /// @brief Check if the region contains a loop. 407 /// 408 /// @param L The loop that might be contained in this region. 409 /// @return True if the loop is contained in the region otherwise false. 410 /// In case a NULL pointer is passed to this function the result 411 /// is false, except for the region that describes the whole function. 412 /// In that case true is returned. 413 bool contains(const Loop *L) const; 414 415 /// @brief Get the outermost loop in the region that contains a loop. 416 /// 417 /// Find for a Loop L the outermost loop OuterL that is a parent loop of L 418 /// and is itself contained in the region. 419 /// 420 /// @param L The loop the lookup is started. 421 /// @return The outermost loop in the region, NULL if such a loop does not 422 /// exist or if the region describes the whole function. 423 Loop *outermostLoopInRegion(Loop *L) const; 424 425 /// @brief Get the outermost loop in the region that contains a basic block. 426 /// 427 /// Find for a basic block BB the outermost loop L that contains BB and is 428 /// itself contained in the region. 429 /// 430 /// @param LI A pointer to a LoopInfo analysis. 431 /// @param BB The basic block surrounded by the loop. 432 /// @return The outermost loop in the region, NULL if such a loop does not 433 /// exist or if the region describes the whole function. 434 Loop *outermostLoopInRegion(LoopInfo *LI, BasicBlock* BB) const; 435 436 /// @brief Get the subregion that starts at a BasicBlock 437 /// 438 /// @param BB The BasicBlock the subregion should start. 439 /// @return The Subregion if available, otherwise NULL. 440 Region* getSubRegionNode(BasicBlock *BB) const; 441 442 /// @brief Get the RegionNode for a BasicBlock 443 /// 444 /// @param BB The BasicBlock at which the RegionNode should start. 445 /// @return If available, the RegionNode that represents the subregion 446 /// starting at BB. If no subregion starts at BB, the RegionNode 447 /// representing BB. 448 RegionNode* getNode(BasicBlock *BB) const; 449 450 /// @brief Get the BasicBlock RegionNode for a BasicBlock 451 /// 452 /// @param BB The BasicBlock for which the RegionNode is requested. 453 /// @return The RegionNode representing the BB. 454 RegionNode* getBBNode(BasicBlock *BB) const; 455 456 /// @brief Add a new subregion to this Region. 457 /// 458 /// @param SubRegion The new subregion that will be added. 459 /// @param moveChildren Move the children of this region, that are also 460 /// contained in SubRegion into SubRegion. 461 void addSubRegion(Region *SubRegion, bool moveChildren = false); 462 463 /// @brief Remove a subregion from this Region. 464 /// 465 /// The subregion is not deleted, as it will probably be inserted into another 466 /// region. 467 /// @param SubRegion The SubRegion that will be removed. 468 Region *removeSubRegion(Region *SubRegion); 469 470 /// @brief Move all direct child nodes of this Region to another Region. 471 /// 472 /// @param To The Region the child nodes will be transferred to. 473 void transferChildrenTo(Region *To); 474 475 /// @brief Verify if the region is a correct region. 476 /// 477 /// Check if this is a correctly build Region. This is an expensive check, as 478 /// the complete CFG of the Region will be walked. 479 void verifyRegion() const; 480 481 /// @brief Clear the cache for BB RegionNodes. 482 /// 483 /// After calling this function the BasicBlock RegionNodes will be stored at 484 /// different memory locations. RegionNodes obtained before this function is 485 /// called are therefore not comparable to RegionNodes abtained afterwords. 486 void clearNodeCache(); 487 488 /// @name Subregion Iterators 489 /// 490 /// These iterators iterator over all subregions of this Region. 491 //@{ 492 typedef RegionSet::iterator iterator; 493 typedef RegionSet::const_iterator const_iterator; 494 495 iterator begin() { return children.begin(); } 496 iterator end() { return children.end(); } 497 498 const_iterator begin() const { return children.begin(); } 499 const_iterator end() const { return children.end(); } 500 //@} 501 502 /// @name BasicBlock Iterators 503 /// 504 /// These iterators iterate over all BasicBlocks that are contained in this 505 /// Region. The iterator also iterates over BasicBlocks that are elements of 506 /// a subregion of this Region. It is therefore called a flat iterator. 507 //@{ 508 template <bool IsConst> 509 class block_iterator_wrapper 510 : public df_iterator<typename std::conditional<IsConst, const BasicBlock, 511 BasicBlock>::type *> { 512 typedef df_iterator<typename std::conditional<IsConst, const BasicBlock, 513 BasicBlock>::type *> super; 514 515 public: 516 typedef block_iterator_wrapper<IsConst> Self; 517 typedef typename super::pointer pointer; 518 519 // Construct the begin iterator. 520 block_iterator_wrapper(pointer Entry, pointer Exit) : super(df_begin(Entry)) 521 { 522 // Mark the exit of the region as visited, so that the children of the 523 // exit and the exit itself, i.e. the block outside the region will never 524 // be visited. 525 super::Visited.insert(Exit); 526 } 527 528 // Construct the end iterator. 529 block_iterator_wrapper() : super(df_end<pointer>((BasicBlock *)nullptr)) {} 530 531 /*implicit*/ block_iterator_wrapper(super I) : super(I) {} 532 533 // FIXME: Even a const_iterator returns a non-const BasicBlock pointer. 534 // This was introduced for backwards compatibility, but should 535 // be removed as soon as all users are fixed. 536 BasicBlock *operator*() const { 537 return const_cast<BasicBlock*>(super::operator*()); 538 } 539 }; 540 541 typedef block_iterator_wrapper<false> block_iterator; 542 typedef block_iterator_wrapper<true> const_block_iterator; 543 544 block_iterator block_begin() { 545 return block_iterator(getEntry(), getExit()); 546 } 547 548 block_iterator block_end() { 549 return block_iterator(); 550 } 551 552 const_block_iterator block_begin() const { 553 return const_block_iterator(getEntry(), getExit()); 554 } 555 const_block_iterator block_end() const { 556 return const_block_iterator(); 557 } 558 559 typedef iterator_range<block_iterator> block_range; 560 typedef iterator_range<const_block_iterator> const_block_range; 561 562 /// @brief Returns a range view of the basic blocks in the region. 563 inline block_range blocks() { 564 return block_range(block_begin(), block_end()); 565 } 566 567 /// @brief Returns a range view of the basic blocks in the region. 568 /// 569 /// This is the 'const' version of the range view. 570 inline const_block_range blocks() const { 571 return const_block_range(block_begin(), block_end()); 572 } 573 //@} 574 575 /// @name Element Iterators 576 /// 577 /// These iterators iterate over all BasicBlock and subregion RegionNodes that 578 /// are direct children of this Region. It does not iterate over any 579 /// RegionNodes that are also element of a subregion of this Region. 580 //@{ 581 typedef df_iterator<RegionNode*, SmallPtrSet<RegionNode*, 8>, false, 582 GraphTraits<RegionNode*> > element_iterator; 583 584 typedef df_iterator<const RegionNode*, SmallPtrSet<const RegionNode*, 8>, 585 false, GraphTraits<const RegionNode*> > 586 const_element_iterator; 587 588 element_iterator element_begin(); 589 element_iterator element_end(); 590 591 const_element_iterator element_begin() const; 592 const_element_iterator element_end() const; 593 //@} 594 }; 595 596 //===----------------------------------------------------------------------===// 597 /// @brief Analysis that detects all canonical Regions. 598 /// 599 /// The RegionInfo pass detects all canonical regions in a function. The Regions 600 /// are connected using the parent relation. This builds a Program Structure 601 /// Tree. 602 class RegionInfo : public FunctionPass { 603 typedef DenseMap<BasicBlock*,BasicBlock*> BBtoBBMap; 604 typedef DenseMap<BasicBlock*, Region*> BBtoRegionMap; 605 typedef SmallPtrSet<Region*, 4> RegionSet; 606 607 RegionInfo(const RegionInfo &) LLVM_DELETED_FUNCTION; 608 const RegionInfo &operator=(const RegionInfo &) LLVM_DELETED_FUNCTION; 609 610 DominatorTree *DT; 611 PostDominatorTree *PDT; 612 DominanceFrontier *DF; 613 614 /// The top level region. 615 Region *TopLevelRegion; 616 617 /// Map every BB to the smallest region, that contains BB. 618 BBtoRegionMap BBtoRegion; 619 620 // isCommonDomFrontier - Returns true if BB is in the dominance frontier of 621 // entry, because it was inherited from exit. In the other case there is an 622 // edge going from entry to BB without passing exit. 623 bool isCommonDomFrontier(BasicBlock* BB, BasicBlock* entry, 624 BasicBlock* exit) const; 625 626 // isRegion - Check if entry and exit surround a valid region, based on 627 // dominance tree and dominance frontier. 628 bool isRegion(BasicBlock* entry, BasicBlock* exit) const; 629 630 // insertShortCut - Saves a shortcut pointing from entry to exit. 631 // This function may extend this shortcut if possible. 632 void insertShortCut(BasicBlock* entry, BasicBlock* exit, 633 BBtoBBMap* ShortCut) const; 634 635 // getNextPostDom - Returns the next BB that postdominates N, while skipping 636 // all post dominators that cannot finish a canonical region. 637 DomTreeNode *getNextPostDom(DomTreeNode* N, BBtoBBMap *ShortCut) const; 638 639 // isTrivialRegion - A region is trivial, if it contains only one BB. 640 bool isTrivialRegion(BasicBlock *entry, BasicBlock *exit) const; 641 642 // createRegion - Creates a single entry single exit region. 643 Region *createRegion(BasicBlock *entry, BasicBlock *exit); 644 645 // findRegionsWithEntry - Detect all regions starting with bb 'entry'. 646 void findRegionsWithEntry(BasicBlock *entry, BBtoBBMap *ShortCut); 647 648 // scanForRegions - Detects regions in F. 649 void scanForRegions(Function &F, BBtoBBMap *ShortCut); 650 651 // getTopMostParent - Get the top most parent with the same entry block. 652 Region *getTopMostParent(Region *region); 653 654 // buildRegionsTree - build the region hierarchy after all region detected. 655 void buildRegionsTree(DomTreeNode *N, Region *region); 656 657 // Calculate - detecte all regions in function and build the region tree. 658 void Calculate(Function& F); 659 660 void releaseMemory() override; 661 662 // updateStatistics - Update statistic about created regions. 663 void updateStatistics(Region *R); 664 665 // isSimple - Check if a region is a simple region with exactly one entry 666 // edge and exactly one exit edge. 667 bool isSimple(Region* R) const; 668 669 public: 670 static char ID; 671 explicit RegionInfo(); 672 673 ~RegionInfo(); 674 675 /// @name FunctionPass interface 676 //@{ 677 bool runOnFunction(Function &F) override; 678 void getAnalysisUsage(AnalysisUsage &AU) const override; 679 void print(raw_ostream &OS, const Module *) const override; 680 void verifyAnalysis() const override; 681 //@} 682 683 /// @brief Get the smallest region that contains a BasicBlock. 684 /// 685 /// @param BB The basic block. 686 /// @return The smallest region, that contains BB or NULL, if there is no 687 /// region containing BB. 688 Region *getRegionFor(BasicBlock *BB) const; 689 690 /// @brief Set the smallest region that surrounds a basic block. 691 /// 692 /// @param BB The basic block surrounded by a region. 693 /// @param R The smallest region that surrounds BB. 694 void setRegionFor(BasicBlock *BB, Region *R); 695 696 /// @brief A shortcut for getRegionFor(). 697 /// 698 /// @param BB The basic block. 699 /// @return The smallest region, that contains BB or NULL, if there is no 700 /// region containing BB. 701 Region *operator[](BasicBlock *BB) const; 702 703 /// @brief Return the exit of the maximal refined region, that starts at a 704 /// BasicBlock. 705 /// 706 /// @param BB The BasicBlock the refined region starts. 707 BasicBlock *getMaxRegionExit(BasicBlock *BB) const; 708 709 /// @brief Find the smallest region that contains two regions. 710 /// 711 /// @param A The first region. 712 /// @param B The second region. 713 /// @return The smallest region containing A and B. 714 Region *getCommonRegion(Region* A, Region *B) const; 715 716 /// @brief Find the smallest region that contains two basic blocks. 717 /// 718 /// @param A The first basic block. 719 /// @param B The second basic block. 720 /// @return The smallest region that contains A and B. 721 Region* getCommonRegion(BasicBlock* A, BasicBlock *B) const { 722 return getCommonRegion(getRegionFor(A), getRegionFor(B)); 723 } 724 725 /// @brief Find the smallest region that contains a set of regions. 726 /// 727 /// @param Regions A vector of regions. 728 /// @return The smallest region that contains all regions in Regions. 729 Region* getCommonRegion(SmallVectorImpl<Region*> &Regions) const; 730 731 /// @brief Find the smallest region that contains a set of basic blocks. 732 /// 733 /// @param BBs A vector of basic blocks. 734 /// @return The smallest region that contains all basic blocks in BBS. 735 Region* getCommonRegion(SmallVectorImpl<BasicBlock*> &BBs) const; 736 737 Region *getTopLevelRegion() const { 738 return TopLevelRegion; 739 } 740 741 /// @brief Update RegionInfo after a basic block was split. 742 /// 743 /// @param NewBB The basic block that was created before OldBB. 744 /// @param OldBB The old basic block. 745 void splitBlock(BasicBlock* NewBB, BasicBlock *OldBB); 746 747 /// @brief Clear the Node Cache for all Regions. 748 /// 749 /// @see Region::clearNodeCache() 750 void clearNodeCache() { 751 if (TopLevelRegion) 752 TopLevelRegion->clearNodeCache(); 753 } 754 }; 755 756 inline raw_ostream &operator<<(raw_ostream &OS, const RegionNode &Node) { 757 if (Node.isSubRegion()) 758 return OS << Node.getNodeAs<Region>()->getNameStr(); 759 else 760 return OS << Node.getNodeAs<BasicBlock>()->getName(); 761 } 762 } // End llvm namespace 763 #endif 764 765