1 //===- llvm/Analysis/Dominators.h - Dominator Info Calculation --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the DominatorTree class, which provides fast and efficient
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_ANALYSIS_DOMINATORS_H
16 #define LLVM_ANALYSIS_DOMINATORS_H
18 #include "llvm/Pass.h"
19 #include "llvm/Function.h"
20 #include "llvm/ADT/DenseMap.h"
21 #include "llvm/ADT/DepthFirstIterator.h"
22 #include "llvm/ADT/GraphTraits.h"
23 #include "llvm/ADT/SmallPtrSet.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/Support/CFG.h"
26 #include "llvm/Support/Compiler.h"
27 #include "llvm/Support/raw_ostream.h"
32 //===----------------------------------------------------------------------===//
33 /// DominatorBase - Base class that other, more interesting dominator analyses
36 template <class NodeT>
39 std::vector<NodeT*> Roots;
40 const bool IsPostDominators;
41 inline explicit DominatorBase(bool isPostDom) :
42 Roots(), IsPostDominators(isPostDom) {}
45 /// getRoots - Return the root blocks of the current CFG. This may include
46 /// multiple blocks if we are computing post dominators. For forward
47 /// dominators, this will always be a single block (the entry node).
49 inline const std::vector<NodeT*> &getRoots() const { return Roots; }
51 /// isPostDominator - Returns true if analysis based of postdoms
53 bool isPostDominator() const { return IsPostDominators; }
57 //===----------------------------------------------------------------------===//
58 // DomTreeNode - Dominator Tree Node
59 template<class NodeT> class DominatorTreeBase;
60 struct PostDominatorTree;
61 class MachineBasicBlock;
63 template <class NodeT>
64 class DomTreeNodeBase {
66 DomTreeNodeBase<NodeT> *IDom;
67 std::vector<DomTreeNodeBase<NodeT> *> Children;
68 int DFSNumIn, DFSNumOut;
70 template<class N> friend class DominatorTreeBase;
71 friend struct PostDominatorTree;
73 typedef typename std::vector<DomTreeNodeBase<NodeT> *>::iterator iterator;
74 typedef typename std::vector<DomTreeNodeBase<NodeT> *>::const_iterator
77 iterator begin() { return Children.begin(); }
78 iterator end() { return Children.end(); }
79 const_iterator begin() const { return Children.begin(); }
80 const_iterator end() const { return Children.end(); }
82 NodeT *getBlock() const { return TheBB; }
83 DomTreeNodeBase<NodeT> *getIDom() const { return IDom; }
84 const std::vector<DomTreeNodeBase<NodeT>*> &getChildren() const {
88 DomTreeNodeBase(NodeT *BB, DomTreeNodeBase<NodeT> *iDom)
89 : TheBB(BB), IDom(iDom), DFSNumIn(-1), DFSNumOut(-1) { }
91 DomTreeNodeBase<NodeT> *addChild(DomTreeNodeBase<NodeT> *C) {
92 Children.push_back(C);
96 size_t getNumChildren() const {
97 return Children.size();
100 void clearAllChildren() {
104 bool compare(DomTreeNodeBase<NodeT> *Other) {
105 if (getNumChildren() != Other->getNumChildren())
108 SmallPtrSet<NodeT *, 4> OtherChildren;
109 for (iterator I = Other->begin(), E = Other->end(); I != E; ++I) {
110 NodeT *Nd = (*I)->getBlock();
111 OtherChildren.insert(Nd);
114 for (iterator I = begin(), E = end(); I != E; ++I) {
115 NodeT *N = (*I)->getBlock();
116 if (OtherChildren.count(N) == 0)
122 void setIDom(DomTreeNodeBase<NodeT> *NewIDom) {
123 assert(IDom && "No immediate dominator?");
124 if (IDom != NewIDom) {
125 typename std::vector<DomTreeNodeBase<NodeT>*>::iterator I =
126 std::find(IDom->Children.begin(), IDom->Children.end(), this);
127 assert(I != IDom->Children.end() &&
128 "Not in immediate dominator children set!");
129 // I am no longer your child...
130 IDom->Children.erase(I);
132 // Switch to new dominator
134 IDom->Children.push_back(this);
138 /// getDFSNumIn/getDFSNumOut - These are an internal implementation detail, do
140 unsigned getDFSNumIn() const { return DFSNumIn; }
141 unsigned getDFSNumOut() const { return DFSNumOut; }
143 // Return true if this node is dominated by other. Use this only if DFS info
145 bool DominatedBy(const DomTreeNodeBase<NodeT> *other) const {
146 return this->DFSNumIn >= other->DFSNumIn &&
147 this->DFSNumOut <= other->DFSNumOut;
151 EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<BasicBlock>);
152 EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<MachineBasicBlock>);
154 template<class NodeT>
155 static raw_ostream &operator<<(raw_ostream &o,
156 const DomTreeNodeBase<NodeT> *Node) {
157 if (Node->getBlock())
158 WriteAsOperand(o, Node->getBlock(), false);
160 o << " <<exit node>>";
162 o << " {" << Node->getDFSNumIn() << "," << Node->getDFSNumOut() << "}";
167 template<class NodeT>
168 static void PrintDomTree(const DomTreeNodeBase<NodeT> *N, raw_ostream &o,
170 o.indent(2*Lev) << "[" << Lev << "] " << N;
171 for (typename DomTreeNodeBase<NodeT>::const_iterator I = N->begin(),
172 E = N->end(); I != E; ++I)
173 PrintDomTree<NodeT>(*I, o, Lev+1);
176 typedef DomTreeNodeBase<BasicBlock> DomTreeNode;
178 //===----------------------------------------------------------------------===//
179 /// DominatorTree - Calculate the immediate dominator tree for a function.
182 template<class FuncT, class N>
183 void Calculate(DominatorTreeBase<typename GraphTraits<N>::NodeType>& DT,
186 template<class NodeT>
187 class DominatorTreeBase : public DominatorBase<NodeT> {
189 typedef DenseMap<NodeT*, DomTreeNodeBase<NodeT>*> DomTreeNodeMapType;
190 DomTreeNodeMapType DomTreeNodes;
191 DomTreeNodeBase<NodeT> *RootNode;
194 unsigned int SlowQueries;
195 // Information record used during immediate dominators computation.
202 InfoRec() : DFSNum(0), Parent(0), Semi(0), Label(0) {}
205 DenseMap<NodeT*, NodeT*> IDoms;
207 // Vertex - Map the DFS number to the BasicBlock*
208 std::vector<NodeT*> Vertex;
210 // Info - Collection of information used during the computation of idoms.
211 DenseMap<NodeT*, InfoRec> Info;
214 for (typename DomTreeNodeMapType::iterator I = this->DomTreeNodes.begin(),
215 E = DomTreeNodes.end(); I != E; ++I)
217 DomTreeNodes.clear();
224 // NewBB is split and now it has one successor. Update dominator tree to
225 // reflect this change.
226 template<class N, class GraphT>
227 void Split(DominatorTreeBase<typename GraphT::NodeType>& DT,
228 typename GraphT::NodeType* NewBB) {
229 assert(std::distance(GraphT::child_begin(NewBB),
230 GraphT::child_end(NewBB)) == 1 &&
231 "NewBB should have a single successor!");
232 typename GraphT::NodeType* NewBBSucc = *GraphT::child_begin(NewBB);
234 std::vector<typename GraphT::NodeType*> PredBlocks;
235 typedef GraphTraits<Inverse<N> > InvTraits;
236 for (typename InvTraits::ChildIteratorType PI =
237 InvTraits::child_begin(NewBB),
238 PE = InvTraits::child_end(NewBB); PI != PE; ++PI)
239 PredBlocks.push_back(*PI);
241 assert(!PredBlocks.empty() && "No predblocks?");
243 bool NewBBDominatesNewBBSucc = true;
244 for (typename InvTraits::ChildIteratorType PI =
245 InvTraits::child_begin(NewBBSucc),
246 E = InvTraits::child_end(NewBBSucc); PI != E; ++PI) {
247 typename InvTraits::NodeType *ND = *PI;
248 if (ND != NewBB && !DT.dominates(NewBBSucc, ND) &&
249 DT.isReachableFromEntry(ND)) {
250 NewBBDominatesNewBBSucc = false;
255 // Find NewBB's immediate dominator and create new dominator tree node for
257 NodeT *NewBBIDom = 0;
259 for (i = 0; i < PredBlocks.size(); ++i)
260 if (DT.isReachableFromEntry(PredBlocks[i])) {
261 NewBBIDom = PredBlocks[i];
265 // It's possible that none of the predecessors of NewBB are reachable;
266 // in that case, NewBB itself is unreachable, so nothing needs to be
271 for (i = i + 1; i < PredBlocks.size(); ++i) {
272 if (DT.isReachableFromEntry(PredBlocks[i]))
273 NewBBIDom = DT.findNearestCommonDominator(NewBBIDom, PredBlocks[i]);
276 // Create the new dominator tree node... and set the idom of NewBB.
277 DomTreeNodeBase<NodeT> *NewBBNode = DT.addNewBlock(NewBB, NewBBIDom);
279 // If NewBB strictly dominates other blocks, then it is now the immediate
280 // dominator of NewBBSucc. Update the dominator tree as appropriate.
281 if (NewBBDominatesNewBBSucc) {
282 DomTreeNodeBase<NodeT> *NewBBSuccNode = DT.getNode(NewBBSucc);
283 DT.changeImmediateDominator(NewBBSuccNode, NewBBNode);
288 explicit DominatorTreeBase(bool isPostDom)
289 : DominatorBase<NodeT>(isPostDom), DFSInfoValid(false), SlowQueries(0) {}
290 virtual ~DominatorTreeBase() { reset(); }
292 /// compare - Return false if the other dominator tree base matches this
293 /// dominator tree base. Otherwise return true.
294 bool compare(DominatorTreeBase &Other) const {
296 const DomTreeNodeMapType &OtherDomTreeNodes = Other.DomTreeNodes;
297 if (DomTreeNodes.size() != OtherDomTreeNodes.size())
300 for (typename DomTreeNodeMapType::const_iterator
301 I = this->DomTreeNodes.begin(),
302 E = this->DomTreeNodes.end(); I != E; ++I) {
303 NodeT *BB = I->first;
304 typename DomTreeNodeMapType::const_iterator OI = OtherDomTreeNodes.find(BB);
305 if (OI == OtherDomTreeNodes.end())
308 DomTreeNodeBase<NodeT>* MyNd = I->second;
309 DomTreeNodeBase<NodeT>* OtherNd = OI->second;
311 if (MyNd->compare(OtherNd))
318 virtual void releaseMemory() { reset(); }
320 /// getNode - return the (Post)DominatorTree node for the specified basic
321 /// block. This is the same as using operator[] on this class.
323 inline DomTreeNodeBase<NodeT> *getNode(NodeT *BB) const {
324 typename DomTreeNodeMapType::const_iterator I = DomTreeNodes.find(BB);
325 return I != DomTreeNodes.end() ? I->second : 0;
328 /// getRootNode - This returns the entry node for the CFG of the function. If
329 /// this tree represents the post-dominance relations for a function, however,
330 /// this root may be a node with the block == NULL. This is the case when
331 /// there are multiple exit nodes from a particular function. Consumers of
332 /// post-dominance information must be capable of dealing with this
335 DomTreeNodeBase<NodeT> *getRootNode() { return RootNode; }
336 const DomTreeNodeBase<NodeT> *getRootNode() const { return RootNode; }
338 /// properlyDominates - Returns true iff this dominates N and this != N.
339 /// Note that this is not a constant time operation!
341 bool properlyDominates(const DomTreeNodeBase<NodeT> *A,
342 const DomTreeNodeBase<NodeT> *B) const {
343 if (A == 0 || B == 0) return false;
344 return dominatedBySlowTreeWalk(A, B);
347 inline bool properlyDominates(const NodeT *A, const NodeT *B) {
351 // Cast away the const qualifiers here. This is ok since
352 // this function doesn't actually return the values returned
354 return properlyDominates(getNode(const_cast<NodeT *>(A)),
355 getNode(const_cast<NodeT *>(B)));
358 bool dominatedBySlowTreeWalk(const DomTreeNodeBase<NodeT> *A,
359 const DomTreeNodeBase<NodeT> *B) const {
360 const DomTreeNodeBase<NodeT> *IDom;
361 if (A == 0 || B == 0) return false;
362 while ((IDom = B->getIDom()) != 0 && IDom != A && IDom != B)
363 B = IDom; // Walk up the tree
368 /// isReachableFromEntry - Return true if A is dominated by the entry
369 /// block of the function containing it.
370 bool isReachableFromEntry(const NodeT* A) {
371 assert(!this->isPostDominator() &&
372 "This is not implemented for post dominators");
373 return dominates(&A->getParent()->front(), A);
376 /// dominates - Returns true iff A dominates B. Note that this is not a
377 /// constant time operation!
379 inline bool dominates(const DomTreeNodeBase<NodeT> *A,
380 const DomTreeNodeBase<NodeT> *B) {
382 return true; // A node trivially dominates itself.
384 if (A == 0 || B == 0)
387 // Compare the result of the tree walk and the dfs numbers, if expensive
388 // checks are enabled.
390 assert((!DFSInfoValid ||
391 (dominatedBySlowTreeWalk(A, B) == B->DominatedBy(A))) &&
392 "Tree walk disagrees with dfs numbers!");
396 return B->DominatedBy(A);
398 // If we end up with too many slow queries, just update the
399 // DFS numbers on the theory that we are going to keep querying.
401 if (SlowQueries > 32) {
403 return B->DominatedBy(A);
406 return dominatedBySlowTreeWalk(A, B);
409 inline bool dominates(const NodeT *A, const NodeT *B) {
413 // Cast away the const qualifiers here. This is ok since
414 // this function doesn't actually return the values returned
416 return dominates(getNode(const_cast<NodeT *>(A)),
417 getNode(const_cast<NodeT *>(B)));
420 NodeT *getRoot() const {
421 assert(this->Roots.size() == 1 && "Should always have entry node!");
422 return this->Roots[0];
425 /// findNearestCommonDominator - Find nearest common dominator basic block
426 /// for basic block A and B. If there is no such block then return NULL.
427 NodeT *findNearestCommonDominator(NodeT *A, NodeT *B) {
428 assert(A->getParent() == B->getParent() &&
429 "Two blocks are not in same function");
431 // If either A or B is a entry block then it is nearest common dominator
432 // (for forward-dominators).
433 if (!this->isPostDominator()) {
434 NodeT &Entry = A->getParent()->front();
435 if (A == &Entry || B == &Entry)
439 // If B dominates A then B is nearest common dominator.
443 // If A dominates B then A is nearest common dominator.
447 DomTreeNodeBase<NodeT> *NodeA = getNode(A);
448 DomTreeNodeBase<NodeT> *NodeB = getNode(B);
450 // Collect NodeA dominators set.
451 SmallPtrSet<DomTreeNodeBase<NodeT>*, 16> NodeADoms;
452 NodeADoms.insert(NodeA);
453 DomTreeNodeBase<NodeT> *IDomA = NodeA->getIDom();
455 NodeADoms.insert(IDomA);
456 IDomA = IDomA->getIDom();
459 // Walk NodeB immediate dominators chain and find common dominator node.
460 DomTreeNodeBase<NodeT> *IDomB = NodeB->getIDom();
462 if (NodeADoms.count(IDomB) != 0)
463 return IDomB->getBlock();
465 IDomB = IDomB->getIDom();
471 const NodeT *findNearestCommonDominator(const NodeT *A, const NodeT *B) {
472 // Cast away the const qualifiers here. This is ok since
473 // const is re-introduced on the return type.
474 return findNearestCommonDominator(const_cast<NodeT *>(A),
475 const_cast<NodeT *>(B));
478 //===--------------------------------------------------------------------===//
479 // API to update (Post)DominatorTree information based on modifications to
482 /// addNewBlock - Add a new node to the dominator tree information. This
483 /// creates a new node as a child of DomBB dominator node,linking it into
484 /// the children list of the immediate dominator.
485 DomTreeNodeBase<NodeT> *addNewBlock(NodeT *BB, NodeT *DomBB) {
486 assert(getNode(BB) == 0 && "Block already in dominator tree!");
487 DomTreeNodeBase<NodeT> *IDomNode = getNode(DomBB);
488 assert(IDomNode && "Not immediate dominator specified for block!");
489 DFSInfoValid = false;
490 return DomTreeNodes[BB] =
491 IDomNode->addChild(new DomTreeNodeBase<NodeT>(BB, IDomNode));
494 /// changeImmediateDominator - This method is used to update the dominator
495 /// tree information when a node's immediate dominator changes.
497 void changeImmediateDominator(DomTreeNodeBase<NodeT> *N,
498 DomTreeNodeBase<NodeT> *NewIDom) {
499 assert(N && NewIDom && "Cannot change null node pointers!");
500 DFSInfoValid = false;
504 void changeImmediateDominator(NodeT *BB, NodeT *NewBB) {
505 changeImmediateDominator(getNode(BB), getNode(NewBB));
508 /// eraseNode - Removes a node from the dominator tree. Block must not
509 /// dominate any other blocks. Removes node from its immediate dominator's
510 /// children list. Deletes dominator node associated with basic block BB.
511 void eraseNode(NodeT *BB) {
512 DomTreeNodeBase<NodeT> *Node = getNode(BB);
513 assert(Node && "Removing node that isn't in dominator tree.");
514 assert(Node->getChildren().empty() && "Node is not a leaf node.");
516 // Remove node from immediate dominator's children list.
517 DomTreeNodeBase<NodeT> *IDom = Node->getIDom();
519 typename std::vector<DomTreeNodeBase<NodeT>*>::iterator I =
520 std::find(IDom->Children.begin(), IDom->Children.end(), Node);
521 assert(I != IDom->Children.end() &&
522 "Not in immediate dominator children set!");
523 // I am no longer your child...
524 IDom->Children.erase(I);
527 DomTreeNodes.erase(BB);
531 /// removeNode - Removes a node from the dominator tree. Block must not
532 /// dominate any other blocks. Invalidates any node pointing to removed
534 void removeNode(NodeT *BB) {
535 assert(getNode(BB) && "Removing node that isn't in dominator tree.");
536 DomTreeNodes.erase(BB);
539 /// splitBlock - BB is split and now it has one successor. Update dominator
540 /// tree to reflect this change.
541 void splitBlock(NodeT* NewBB) {
542 if (this->IsPostDominators)
543 this->Split<Inverse<NodeT*>, GraphTraits<Inverse<NodeT*> > >(*this, NewBB);
545 this->Split<NodeT*, GraphTraits<NodeT*> >(*this, NewBB);
548 /// print - Convert to human readable form
550 void print(raw_ostream &o) const {
551 o << "=============================--------------------------------\n";
552 if (this->isPostDominator())
553 o << "Inorder PostDominator Tree: ";
555 o << "Inorder Dominator Tree: ";
556 if (!this->DFSInfoValid)
557 o << "DFSNumbers invalid: " << SlowQueries << " slow queries.";
560 // The postdom tree can have a null root if there are no returns.
562 PrintDomTree<NodeT>(getRootNode(), o, 1);
566 template<class GraphT>
567 friend typename GraphT::NodeType* Eval(
568 DominatorTreeBase<typename GraphT::NodeType>& DT,
569 typename GraphT::NodeType* V,
570 unsigned LastLinked);
572 template<class GraphT>
573 friend unsigned DFSPass(DominatorTreeBase<typename GraphT::NodeType>& DT,
574 typename GraphT::NodeType* V,
577 template<class FuncT, class N>
578 friend void Calculate(DominatorTreeBase<typename GraphTraits<N>::NodeType>& DT,
581 /// updateDFSNumbers - Assign In and Out numbers to the nodes while walking
582 /// dominator tree in dfs order.
583 void updateDFSNumbers() {
586 SmallVector<std::pair<DomTreeNodeBase<NodeT>*,
587 typename DomTreeNodeBase<NodeT>::iterator>, 32> WorkStack;
589 DomTreeNodeBase<NodeT> *ThisRoot = getRootNode();
594 // Even in the case of multiple exits that form the post dominator root
595 // nodes, do not iterate over all exits, but start from the virtual root
596 // node. Otherwise bbs, that are not post dominated by any exit but by the
597 // virtual root node, will never be assigned a DFS number.
598 WorkStack.push_back(std::make_pair(ThisRoot, ThisRoot->begin()));
599 ThisRoot->DFSNumIn = DFSNum++;
601 while (!WorkStack.empty()) {
602 DomTreeNodeBase<NodeT> *Node = WorkStack.back().first;
603 typename DomTreeNodeBase<NodeT>::iterator ChildIt =
604 WorkStack.back().second;
606 // If we visited all of the children of this node, "recurse" back up the
607 // stack setting the DFOutNum.
608 if (ChildIt == Node->end()) {
609 Node->DFSNumOut = DFSNum++;
610 WorkStack.pop_back();
612 // Otherwise, recursively visit this child.
613 DomTreeNodeBase<NodeT> *Child = *ChildIt;
614 ++WorkStack.back().second;
616 WorkStack.push_back(std::make_pair(Child, Child->begin()));
617 Child->DFSNumIn = DFSNum++;
625 DomTreeNodeBase<NodeT> *getNodeForBlock(NodeT *BB) {
626 typename DomTreeNodeMapType::iterator I = this->DomTreeNodes.find(BB);
627 if (I != this->DomTreeNodes.end() && I->second)
630 // Haven't calculated this node yet? Get or calculate the node for the
631 // immediate dominator.
632 NodeT *IDom = getIDom(BB);
634 assert(IDom || this->DomTreeNodes[NULL]);
635 DomTreeNodeBase<NodeT> *IDomNode = getNodeForBlock(IDom);
637 // Add a new tree node for this BasicBlock, and link it as a child of
639 DomTreeNodeBase<NodeT> *C = new DomTreeNodeBase<NodeT>(BB, IDomNode);
640 return this->DomTreeNodes[BB] = IDomNode->addChild(C);
643 inline NodeT *getIDom(NodeT *BB) const {
644 typename DenseMap<NodeT*, NodeT*>::const_iterator I = IDoms.find(BB);
645 return I != IDoms.end() ? I->second : 0;
648 inline void addRoot(NodeT* BB) {
649 this->Roots.push_back(BB);
653 /// recalculate - compute a dominator tree for the given function
655 void recalculate(FT& F) {
657 this->Vertex.push_back(0);
659 if (!this->IsPostDominators) {
661 this->Roots.push_back(&F.front());
662 this->IDoms[&F.front()] = 0;
663 this->DomTreeNodes[&F.front()] = 0;
665 Calculate<FT, NodeT*>(*this, F);
667 // Initialize the roots list
668 for (typename FT::iterator I = F.begin(), E = F.end(); I != E; ++I) {
669 if (std::distance(GraphTraits<FT*>::child_begin(I),
670 GraphTraits<FT*>::child_end(I)) == 0)
673 // Prepopulate maps so that we don't get iterator invalidation issues later.
675 this->DomTreeNodes[I] = 0;
678 Calculate<FT, Inverse<NodeT*> >(*this, F);
683 EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<BasicBlock>);
685 //===-------------------------------------
686 /// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
687 /// compute a normal dominator tree.
689 class DominatorTree : public FunctionPass {
691 static char ID; // Pass ID, replacement for typeid
692 DominatorTreeBase<BasicBlock>* DT;
694 DominatorTree() : FunctionPass(ID) {
695 initializeDominatorTreePass(*PassRegistry::getPassRegistry());
696 DT = new DominatorTreeBase<BasicBlock>(false);
703 DominatorTreeBase<BasicBlock>& getBase() { return *DT; }
705 /// getRoots - Return the root blocks of the current CFG. This may include
706 /// multiple blocks if we are computing post dominators. For forward
707 /// dominators, this will always be a single block (the entry node).
709 inline const std::vector<BasicBlock*> &getRoots() const {
710 return DT->getRoots();
713 inline BasicBlock *getRoot() const {
714 return DT->getRoot();
717 inline DomTreeNode *getRootNode() const {
718 return DT->getRootNode();
721 /// compare - Return false if the other dominator tree matches this
722 /// dominator tree. Otherwise return true.
723 inline bool compare(DominatorTree &Other) const {
724 DomTreeNode *R = getRootNode();
725 DomTreeNode *OtherR = Other.getRootNode();
727 if (!R || !OtherR || R->getBlock() != OtherR->getBlock())
730 if (DT->compare(Other.getBase()))
736 virtual bool runOnFunction(Function &F);
738 virtual void verifyAnalysis() const;
740 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
741 AU.setPreservesAll();
744 inline bool dominates(const DomTreeNode* A, const DomTreeNode* B) const {
745 return DT->dominates(A, B);
748 inline bool dominates(const BasicBlock* A, const BasicBlock* B) const {
749 return DT->dominates(A, B);
752 // dominates - Return true if A dominates B. This performs the
753 // special checks necessary if A and B are in the same basic block.
754 bool dominates(const Instruction *A, const Instruction *B) const;
756 bool properlyDominates(const DomTreeNode *A, const DomTreeNode *B) const {
757 return DT->properlyDominates(A, B);
760 bool properlyDominates(const BasicBlock *A, const BasicBlock *B) const {
761 return DT->properlyDominates(A, B);
764 /// findNearestCommonDominator - Find nearest common dominator basic block
765 /// for basic block A and B. If there is no such block then return NULL.
766 inline BasicBlock *findNearestCommonDominator(BasicBlock *A, BasicBlock *B) {
767 return DT->findNearestCommonDominator(A, B);
770 inline const BasicBlock *findNearestCommonDominator(const BasicBlock *A,
771 const BasicBlock *B) {
772 return DT->findNearestCommonDominator(A, B);
775 inline DomTreeNode *operator[](BasicBlock *BB) const {
776 return DT->getNode(BB);
779 /// getNode - return the (Post)DominatorTree node for the specified basic
780 /// block. This is the same as using operator[] on this class.
782 inline DomTreeNode *getNode(BasicBlock *BB) const {
783 return DT->getNode(BB);
786 /// addNewBlock - Add a new node to the dominator tree information. This
787 /// creates a new node as a child of DomBB dominator node,linking it into
788 /// the children list of the immediate dominator.
789 inline DomTreeNode *addNewBlock(BasicBlock *BB, BasicBlock *DomBB) {
790 return DT->addNewBlock(BB, DomBB);
793 /// changeImmediateDominator - This method is used to update the dominator
794 /// tree information when a node's immediate dominator changes.
796 inline void changeImmediateDominator(BasicBlock *N, BasicBlock* NewIDom) {
797 DT->changeImmediateDominator(N, NewIDom);
800 inline void changeImmediateDominator(DomTreeNode *N, DomTreeNode* NewIDom) {
801 DT->changeImmediateDominator(N, NewIDom);
804 /// eraseNode - Removes a node from the dominator tree. Block must not
805 /// dominate any other blocks. Removes node from its immediate dominator's
806 /// children list. Deletes dominator node associated with basic block BB.
807 inline void eraseNode(BasicBlock *BB) {
811 /// splitBlock - BB is split and now it has one successor. Update dominator
812 /// tree to reflect this change.
813 inline void splitBlock(BasicBlock* NewBB) {
814 DT->splitBlock(NewBB);
817 bool isReachableFromEntry(const BasicBlock* A) {
818 return DT->isReachableFromEntry(A);
822 virtual void releaseMemory() {
826 virtual void print(raw_ostream &OS, const Module* M= 0) const;
829 //===-------------------------------------
830 /// DominatorTree GraphTraits specialization so the DominatorTree can be
831 /// iterable by generic graph iterators.
833 template <> struct GraphTraits<DomTreeNode*> {
834 typedef DomTreeNode NodeType;
835 typedef NodeType::iterator ChildIteratorType;
837 static NodeType *getEntryNode(NodeType *N) {
840 static inline ChildIteratorType child_begin(NodeType *N) {
843 static inline ChildIteratorType child_end(NodeType *N) {
847 typedef df_iterator<DomTreeNode*> nodes_iterator;
849 static nodes_iterator nodes_begin(DomTreeNode *N) {
850 return df_begin(getEntryNode(N));
853 static nodes_iterator nodes_end(DomTreeNode *N) {
854 return df_end(getEntryNode(N));
858 template <> struct GraphTraits<DominatorTree*>
859 : public GraphTraits<DomTreeNode*> {
860 static NodeType *getEntryNode(DominatorTree *DT) {
861 return DT->getRootNode();
864 static nodes_iterator nodes_begin(DominatorTree *N) {
865 return df_begin(getEntryNode(N));
868 static nodes_iterator nodes_end(DominatorTree *N) {
869 return df_end(getEntryNode(N));
874 } // End llvm namespace