-//===- llvm/Analysis/Dominators.h - Dominator Info Calculation ---*- C++ -*--=//
+//===- llvm/Analysis/Dominators.h - Dominator Info Calculation --*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
//
// This file defines the following classes:
-// 1. DominatorSet: Calculates the [reverse] dominator set for a function
-// 2. ImmediateDominators: Calculates and holds a mapping between BasicBlocks
-// and their immediate dominator.
-// 3. DominatorTree: Represent the ImmediateDominator as an explicit tree
-// structure.
-// 4. DominanceFrontier: Calculate and hold the dominance frontier for a
+// 1. DominatorTree: Represent dominators as an explicit tree structure.
+// 2. DominanceFrontier: Calculate and hold the dominance frontier for a
// function.
//
// These data structures are listed in increasing order of complexity. It
-// takes longer to calculate the dominator frontier, for example, than the
-// ImmediateDominator mapping.
-//
+// takes longer to calculate the dominator frontier, for example, than the
+// DominatorTree mapping.
+//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_DOMINATORS_H
#define LLVM_ANALYSIS_DOMINATORS_H
#include "llvm/Pass.h"
+#include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/GraphTraits.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Assembly/Writer.h"
+#include "llvm/Support/CFG.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <map>
#include <set>
-class Instruction;
-template <typename GraphType> struct GraphTraits;
+namespace llvm {
//===----------------------------------------------------------------------===//
-//
-// DominatorBase - Base class that other, more interesting dominator analyses
-// inherit from.
-//
-class DominatorBase : public FunctionPass {
+/// DominatorBase - Base class that other, more interesting dominator analyses
+/// inherit from.
+///
+template <class NodeT>
+class DominatorBase {
protected:
- BasicBlock *Root;
+ std::vector<NodeT*> Roots;
const bool IsPostDominators;
-
- inline DominatorBase(bool isPostDom) : Root(0), IsPostDominators(isPostDom) {}
+ inline explicit DominatorBase(bool isPostDom) :
+ Roots(), IsPostDominators(isPostDom) {}
public:
- inline BasicBlock *getRoot() const { return Root; }
- // Returns true if analysis based of postdoms
+ /// getRoots - Return the root blocks of the current CFG. This may include
+ /// multiple blocks if we are computing post dominators. For forward
+ /// dominators, this will always be a single block (the entry node).
+ ///
+ inline const std::vector<NodeT*> &getRoots() const { return Roots; }
+
+ /// isPostDominator - Returns true if analysis based of postdoms
+ ///
bool isPostDominator() const { return IsPostDominators; }
};
+
//===----------------------------------------------------------------------===//
-//
-// DominatorSet - Maintain a set<BasicBlock*> for every basic block in a
-// function, that represents the blocks that dominate the block.
-//
-class DominatorSetBase : public DominatorBase {
-public:
- typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
- // Map of dom sets
- typedef std::map<BasicBlock*, DomSetType> DomSetMapType;
-protected:
- DomSetMapType Doms;
+// DomTreeNode - Dominator Tree Node
+template<class NodeT> class DominatorTreeBase;
+struct PostDominatorTree;
+class MachineBasicBlock;
+
+template <class NodeT>
+class DomTreeNodeBase {
+ NodeT *TheBB;
+ DomTreeNodeBase<NodeT> *IDom;
+ std::vector<DomTreeNodeBase<NodeT> *> Children;
+ int DFSNumIn, DFSNumOut;
+
+ template<class N> friend class DominatorTreeBase;
+ friend struct PostDominatorTree;
public:
- DominatorSetBase(bool isPostDom) : DominatorBase(isPostDom) {}
-
- virtual void releaseMemory() { Doms.clear(); }
-
- // Accessor interface:
- typedef DomSetMapType::const_iterator const_iterator;
- typedef DomSetMapType::iterator iterator;
- inline const_iterator begin() const { return Doms.begin(); }
- inline iterator begin() { return Doms.begin(); }
- inline const_iterator end() const { return Doms.end(); }
- inline iterator end() { return Doms.end(); }
- inline const_iterator find(BasicBlock* B) const { return Doms.find(B); }
- inline iterator find(BasicBlock* B) { return Doms.find(B); }
+ typedef typename std::vector<DomTreeNodeBase<NodeT> *>::iterator iterator;
+ typedef typename std::vector<DomTreeNodeBase<NodeT> *>::const_iterator
+ const_iterator;
+
+ iterator begin() { return Children.begin(); }
+ iterator end() { return Children.end(); }
+ const_iterator begin() const { return Children.begin(); }
+ const_iterator end() const { return Children.end(); }
+
+ NodeT *getBlock() const { return TheBB; }
+ DomTreeNodeBase<NodeT> *getIDom() const { return IDom; }
+ const std::vector<DomTreeNodeBase<NodeT>*> &getChildren() const {
+ return Children;
+ }
+ DomTreeNodeBase(NodeT *BB, DomTreeNodeBase<NodeT> *iDom)
+ : TheBB(BB), IDom(iDom), DFSNumIn(-1), DFSNumOut(-1) { }
- /// getDominators - Return the set of basic blocks that dominate the specified
- /// block.
- ///
- inline const DomSetType &getDominators(BasicBlock *BB) const {
- const_iterator I = find(BB);
- assert(I != end() && "BB not in function!");
- return I->second;
+ DomTreeNodeBase<NodeT> *addChild(DomTreeNodeBase<NodeT> *C) {
+ Children.push_back(C);
+ return C;
}
- /// dominates - Return true if A dominates B.
- ///
- inline bool dominates(BasicBlock *A, BasicBlock *B) const {
- return getDominators(B).count(A) != 0;
+ size_t getNumChildren() const {
+ return Children.size();
}
- /// properlyDominates - Return true if A dominates B and A != B.
- ///
- bool properlyDominates(BasicBlock *A, BasicBlock *B) const {
- return dominates(A, B) && A != B;
+ void clearAllChildren() {
+ Children.clear();
}
- /// print - Convert to human readable form
- virtual void print(std::ostream &OS) const;
+ bool compare(DomTreeNodeBase<NodeT> *Other) {
+ if (getNumChildren() != Other->getNumChildren())
+ return true;
- /// dominates - Return true if A dominates B. This performs the special
- /// checks neccesary if A and B are in the same basic block.
- ///
- bool dominates(Instruction *A, Instruction *B) const;
+ SmallPtrSet<NodeT *, 4> OtherChildren;
+ for (iterator I = Other->begin(), E = Other->end(); I != E; ++I) {
+ NodeT *Nd = (*I)->getBlock();
+ OtherChildren.insert(Nd);
+ }
- //===--------------------------------------------------------------------===//
- // API to update (Post)DominatorSet information based on modifications to
- // the CFG...
+ for (iterator I = begin(), E = end(); I != E; ++I) {
+ NodeT *N = (*I)->getBlock();
+ if (OtherChildren.count(N) == 0)
+ return true;
+ }
+ return false;
+ }
- /// addBasicBlock - Call to update the dominator set with information about a
- /// new block that was inserted into the function.
- void addBasicBlock(BasicBlock *BB, const DomSetType &Dominators) {
- assert(find(BB) == end() && "Block already in DominatorSet!");
- Doms.insert(std::make_pair(BB, Dominators));
+ void setIDom(DomTreeNodeBase<NodeT> *NewIDom) {
+ assert(IDom && "No immediate dominator?");
+ if (IDom != NewIDom) {
+ typename std::vector<DomTreeNodeBase<NodeT>*>::iterator I =
+ std::find(IDom->Children.begin(), IDom->Children.end(), this);
+ assert(I != IDom->Children.end() &&
+ "Not in immediate dominator children set!");
+ // I am no longer your child...
+ IDom->Children.erase(I);
+
+ // Switch to new dominator
+ IDom = NewIDom;
+ IDom->Children.push_back(this);
+ }
}
- // addDominator - If a new block is inserted into the CFG, then method may be
- // called to notify the blocks it dominates that it is in their set.
- //
- void addDominator(BasicBlock *BB, BasicBlock *NewDominator) {
- iterator I = find(BB);
- assert(I != end() && "BB is not in DominatorSet!");
- I->second.insert(NewDominator);
+ /// getDFSNumIn/getDFSNumOut - These are an internal implementation detail, do
+ /// not call them.
+ unsigned getDFSNumIn() const { return DFSNumIn; }
+ unsigned getDFSNumOut() const { return DFSNumOut; }
+private:
+ // Return true if this node is dominated by other. Use this only if DFS info
+ // is valid.
+ bool DominatedBy(const DomTreeNodeBase<NodeT> *other) const {
+ return this->DFSNumIn >= other->DFSNumIn &&
+ this->DFSNumOut <= other->DFSNumOut;
}
};
+EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<BasicBlock>);
+EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<MachineBasicBlock>);
-//===-------------------------------------
-// DominatorSet Class - Concrete subclass of DominatorSetBase that is used to
-// compute a normal dominator set.
-//
-struct DominatorSet : public DominatorSetBase {
- DominatorSet() : DominatorSetBase(false) {}
+template<class NodeT>
+static raw_ostream &operator<<(raw_ostream &o,
+ const DomTreeNodeBase<NodeT> *Node) {
+ if (Node->getBlock())
+ WriteAsOperand(o, Node->getBlock(), false);
+ else
+ o << " <<exit node>>";
- virtual bool runOnFunction(Function &F);
+ o << " {" << Node->getDFSNumIn() << "," << Node->getDFSNumOut() << "}";
- /// recalculate - This method may be called by external passes that modify the
- /// CFG and then need dominator information recalculated. This method is
- /// obviously really slow, so it should be avoided if at all possible.
- void recalculate();
+ return o << "\n";
+}
- // getAnalysisUsage - This simply provides a dominator set
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesAll();
- }
-private:
- void calculateDominatorsFromBlock(BasicBlock *BB);
-};
+template<class NodeT>
+static void PrintDomTree(const DomTreeNodeBase<NodeT> *N, raw_ostream &o,
+ unsigned Lev) {
+ o.indent(2*Lev) << "[" << Lev << "] " << N;
+ for (typename DomTreeNodeBase<NodeT>::const_iterator I = N->begin(),
+ E = N->end(); I != E; ++I)
+ PrintDomTree<NodeT>(*I, o, Lev+1);
+}
+typedef DomTreeNodeBase<BasicBlock> DomTreeNode;
//===----------------------------------------------------------------------===//
-//
-// ImmediateDominators - Calculate the immediate dominator for each node in a
-// function.
-//
-class ImmediateDominatorsBase : public DominatorBase {
+/// DominatorTree - Calculate the immediate dominator tree for a function.
+///
+
+template<class FuncT, class N>
+void Calculate(DominatorTreeBase<typename GraphTraits<N>::NodeType>& DT,
+ FuncT& F);
+
+template<class NodeT>
+class DominatorTreeBase : public DominatorBase<NodeT> {
protected:
- std::map<BasicBlock*, BasicBlock*> IDoms;
- void calcIDoms(const DominatorSetBase &DS);
+ typedef DenseMap<NodeT*, DomTreeNodeBase<NodeT>*> DomTreeNodeMapType;
+ DomTreeNodeMapType DomTreeNodes;
+ DomTreeNodeBase<NodeT> *RootNode;
+
+ bool DFSInfoValid;
+ unsigned int SlowQueries;
+ // Information record used during immediate dominators computation.
+ struct InfoRec {
+ unsigned DFSNum;
+ unsigned Semi;
+ unsigned Size;
+ NodeT *Label, *Child;
+ unsigned Parent, Ancestor;
+
+ std::vector<NodeT*> Bucket;
+
+ InfoRec() : DFSNum(0), Semi(0), Size(0), Label(0), Child(0), Parent(0),
+ Ancestor(0) {}
+ };
+
+ DenseMap<NodeT*, NodeT*> IDoms;
+
+ // Vertex - Map the DFS number to the BasicBlock*
+ std::vector<NodeT*> Vertex;
+
+ // Info - Collection of information used during the computation of idoms.
+ DenseMap<NodeT*, InfoRec> Info;
+
+ void reset() {
+ for (typename DomTreeNodeMapType::iterator I = this->DomTreeNodes.begin(),
+ E = DomTreeNodes.end(); I != E; ++I)
+ delete I->second;
+ DomTreeNodes.clear();
+ IDoms.clear();
+ this->Roots.clear();
+ Vertex.clear();
+ RootNode = 0;
+ }
+
+ // NewBB is split and now it has one successor. Update dominator tree to
+ // reflect this change.
+ template<class N, class GraphT>
+ void Split(DominatorTreeBase<typename GraphT::NodeType>& DT,
+ typename GraphT::NodeType* NewBB) {
+ assert(std::distance(GraphT::child_begin(NewBB),
+ GraphT::child_end(NewBB)) == 1 &&
+ "NewBB should have a single successor!");
+ typename GraphT::NodeType* NewBBSucc = *GraphT::child_begin(NewBB);
+
+ std::vector<typename GraphT::NodeType*> PredBlocks;
+ typedef GraphTraits<Inverse<N> > InvTraits;
+ for (typename InvTraits::ChildIteratorType PI =
+ InvTraits::child_begin(NewBB),
+ PE = InvTraits::child_end(NewBB); PI != PE; ++PI)
+ PredBlocks.push_back(*PI);
+
+ assert(!PredBlocks.empty() && "No predblocks?");
+
+ bool NewBBDominatesNewBBSucc = true;
+ for (typename InvTraits::ChildIteratorType PI =
+ InvTraits::child_begin(NewBBSucc),
+ E = InvTraits::child_end(NewBBSucc); PI != E; ++PI) {
+ typename InvTraits::NodeType *ND = *PI;
+ if (ND != NewBB && !DT.dominates(NewBBSucc, ND) &&
+ DT.isReachableFromEntry(ND)) {
+ NewBBDominatesNewBBSucc = false;
+ break;
+ }
+ }
+
+ // Find NewBB's immediate dominator and create new dominator tree node for
+ // NewBB.
+ NodeT *NewBBIDom = 0;
+ unsigned i = 0;
+ for (i = 0; i < PredBlocks.size(); ++i)
+ if (DT.isReachableFromEntry(PredBlocks[i])) {
+ NewBBIDom = PredBlocks[i];
+ break;
+ }
+
+ // It's possible that none of the predecessors of NewBB are reachable;
+ // in that case, NewBB itself is unreachable, so nothing needs to be
+ // changed.
+ if (!NewBBIDom)
+ return;
+
+ for (i = i + 1; i < PredBlocks.size(); ++i) {
+ if (DT.isReachableFromEntry(PredBlocks[i]))
+ NewBBIDom = DT.findNearestCommonDominator(NewBBIDom, PredBlocks[i]);
+ }
+
+ // Create the new dominator tree node... and set the idom of NewBB.
+ DomTreeNodeBase<NodeT> *NewBBNode = DT.addNewBlock(NewBB, NewBBIDom);
+
+ // If NewBB strictly dominates other blocks, then it is now the immediate
+ // dominator of NewBBSucc. Update the dominator tree as appropriate.
+ if (NewBBDominatesNewBBSucc) {
+ DomTreeNodeBase<NodeT> *NewBBSuccNode = DT.getNode(NewBBSucc);
+ DT.changeImmediateDominator(NewBBSuccNode, NewBBNode);
+ }
+ }
+
public:
- ImmediateDominatorsBase(bool isPostDom) : DominatorBase(isPostDom) {}
+ explicit DominatorTreeBase(bool isPostDom)
+ : DominatorBase<NodeT>(isPostDom), DFSInfoValid(false), SlowQueries(0) {}
+ virtual ~DominatorTreeBase() { reset(); }
+
+ // FIXME: Should remove this
+ virtual bool runOnFunction(Function &F) { return false; }
+
+ /// compare - Return false if the other dominator tree base matches this
+ /// dominator tree base. Otherwise return true.
+ bool compare(DominatorTreeBase &Other) const {
+
+ const DomTreeNodeMapType &OtherDomTreeNodes = Other.DomTreeNodes;
+ if (DomTreeNodes.size() != OtherDomTreeNodes.size())
+ return true;
+
+ for (typename DomTreeNodeMapType::const_iterator
+ I = this->DomTreeNodes.begin(),
+ E = this->DomTreeNodes.end(); I != E; ++I) {
+ NodeT *BB = I->first;
+ typename DomTreeNodeMapType::const_iterator OI = OtherDomTreeNodes.find(BB);
+ if (OI == OtherDomTreeNodes.end())
+ return true;
+
+ DomTreeNodeBase<NodeT>* MyNd = I->second;
+ DomTreeNodeBase<NodeT>* OtherNd = OI->second;
+
+ if (MyNd->compare(OtherNd))
+ return true;
+ }
- virtual void releaseMemory() { IDoms.clear(); }
+ return false;
+ }
- // Accessor interface:
- typedef std::map<BasicBlock*, BasicBlock*> IDomMapType;
- typedef IDomMapType::const_iterator const_iterator;
- inline const_iterator begin() const { return IDoms.begin(); }
- inline const_iterator end() const { return IDoms.end(); }
- inline const_iterator find(BasicBlock* B) const { return IDoms.find(B);}
-
- // operator[] - Return the idom for the specified basic block. The start
- // node returns null, because it does not have an immediate dominator.
- //
- inline BasicBlock *operator[](BasicBlock *BB) const {
- return get(BB);
- }
-
- // get() - Synonym for operator[].
- inline BasicBlock *get(BasicBlock *BB) const {
- std::map<BasicBlock*, BasicBlock*>::const_iterator I = IDoms.find(BB);
- return I != IDoms.end() ? I->second : 0;
+ virtual void releaseMemory() { reset(); }
+
+ /// getNode - return the (Post)DominatorTree node for the specified basic
+ /// block. This is the same as using operator[] on this class.
+ ///
+ inline DomTreeNodeBase<NodeT> *getNode(NodeT *BB) const {
+ typename DomTreeNodeMapType::const_iterator I = DomTreeNodes.find(BB);
+ return I != DomTreeNodes.end() ? I->second : 0;
}
- //===--------------------------------------------------------------------===//
- // API to update Immediate(Post)Dominators information based on modifications
- // to the CFG...
+ /// getRootNode - This returns the entry node for the CFG of the function. If
+ /// this tree represents the post-dominance relations for a function, however,
+ /// this root may be a node with the block == NULL. This is the case when
+ /// there are multiple exit nodes from a particular function. Consumers of
+ /// post-dominance information must be capable of dealing with this
+ /// possibility.
+ ///
+ DomTreeNodeBase<NodeT> *getRootNode() { return RootNode; }
+ const DomTreeNodeBase<NodeT> *getRootNode() const { return RootNode; }
- /// addNewBlock - Add a new block to the CFG, with the specified immediate
- /// dominator.
+ /// properlyDominates - Returns true iff this dominates N and this != N.
+ /// Note that this is not a constant time operation!
///
- void addNewBlock(BasicBlock *BB, BasicBlock *IDom) {
- assert(get(BB) == 0 && "BasicBlock already in idom info!");
- IDoms[BB] = IDom;
+ bool properlyDominates(const DomTreeNodeBase<NodeT> *A,
+ const DomTreeNodeBase<NodeT> *B) const {
+ if (A == 0 || B == 0) return false;
+ return dominatedBySlowTreeWalk(A, B);
}
- /// setImmediateDominator - Update the immediate dominator information to
- /// change the current immediate dominator for the specified block to another
- /// block. This method requires that BB already have an IDom, otherwise just
- /// use addNewBlock.
- void setImmediateDominator(BasicBlock *BB, BasicBlock *NewIDom) {
- assert(IDoms.find(BB) != IDoms.end() && "BB doesn't have idom yet!");
- IDoms[BB] = NewIDom;
+ inline bool properlyDominates(const NodeT *A, const NodeT *B) {
+ if (A == B)
+ return false;
+
+ // Cast away the const qualifiers here. This is ok since
+ // this function doesn't actually return the values returned
+ // from getNode.
+ return properlyDominates(getNode(const_cast<NodeT *>(A)),
+ getNode(const_cast<NodeT *>(B)));
}
- // print - Convert to human readable form
- virtual void print(std::ostream &OS) const;
-};
+ bool dominatedBySlowTreeWalk(const DomTreeNodeBase<NodeT> *A,
+ const DomTreeNodeBase<NodeT> *B) const {
+ const DomTreeNodeBase<NodeT> *IDom;
+ if (A == 0 || B == 0) return false;
+ while ((IDom = B->getIDom()) != 0 && IDom != A && IDom != B)
+ B = IDom; // Walk up the tree
+ return IDom != 0;
+ }
-//===-------------------------------------
-// ImmediateDominators Class - Concrete subclass of ImmediateDominatorsBase that
-// is used to compute a normal immediate dominator set.
-//
-struct ImmediateDominators : public ImmediateDominatorsBase {
- ImmediateDominators() : ImmediateDominatorsBase(false) {}
-
- virtual bool runOnFunction(Function &F) {
- IDoms.clear(); // Reset from the last time we were run...
- DominatorSet &DS = getAnalysis<DominatorSet>();
- Root = DS.getRoot();
- calcIDoms(DS);
- return false;
+
+ /// isReachableFromEntry - Return true if A is dominated by the entry
+ /// block of the function containing it.
+ bool isReachableFromEntry(const NodeT* A) {
+ assert(!this->isPostDominator() &&
+ "This is not implemented for post dominators");
+ return dominates(&A->getParent()->front(), A);
}
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesAll();
- AU.addRequired<DominatorSet>();
+ /// dominates - Returns true iff A dominates B. Note that this is not a
+ /// constant time operation!
+ ///
+ inline bool dominates(const DomTreeNodeBase<NodeT> *A,
+ const DomTreeNodeBase<NodeT> *B) {
+ if (B == A)
+ return true; // A node trivially dominates itself.
+
+ if (A == 0 || B == 0)
+ return false;
+
+ // Compare the result of the tree walk and the dfs numbers, if expensive
+ // checks are enabled.
+#ifdef XDEBUG
+ assert((!DFSInfoValid ||
+ (dominatedBySlowTreeWalk(A, B) == B->DominatedBy(A))) &&
+ "Tree walk disagrees with dfs numbers!");
+#endif
+
+ if (DFSInfoValid)
+ return B->DominatedBy(A);
+
+ // If we end up with too many slow queries, just update the
+ // DFS numbers on the theory that we are going to keep querying.
+ SlowQueries++;
+ if (SlowQueries > 32) {
+ updateDFSNumbers();
+ return B->DominatedBy(A);
+ }
+
+ return dominatedBySlowTreeWalk(A, B);
}
-};
+ inline bool dominates(const NodeT *A, const NodeT *B) {
+ if (A == B)
+ return true;
-//===----------------------------------------------------------------------===//
-//
-// DominatorTree - Calculate the immediate dominator tree for a function.
-//
-class DominatorTreeBase : public DominatorBase {
-protected:
- class Node2;
-public:
- typedef Node2 Node;
-protected:
- std::map<BasicBlock*, Node*> Nodes;
- void reset();
- typedef std::map<BasicBlock*, Node*> NodeMapType;
-public:
- class Node2 {
- friend class DominatorTree;
- friend class PostDominatorTree;
- friend class DominatorTreeBase;
- BasicBlock *TheNode;
- Node2 *IDom;
- std::vector<Node*> Children;
- public:
- typedef std::vector<Node*>::iterator iterator;
- typedef std::vector<Node*>::const_iterator const_iterator;
-
- iterator begin() { return Children.begin(); }
- iterator end() { return Children.end(); }
- const_iterator begin() const { return Children.begin(); }
- const_iterator end() const { return Children.end(); }
-
- inline BasicBlock *getNode() const { return TheNode; }
- inline Node2 *getIDom() const { return IDom; }
- inline const std::vector<Node*> &getChildren() const { return Children; }
-
- // dominates - Returns true iff this dominates N. Note that this is not a
- // constant time operation!
- inline bool dominates(const Node2 *N) const {
- const Node2 *IDom;
- while ((IDom = N->getIDom()) != 0 && IDom != this)
- N = IDom; // Walk up the tree
- return IDom != 0;
+ // Cast away the const qualifiers here. This is ok since
+ // this function doesn't actually return the values returned
+ // from getNode.
+ return dominates(getNode(const_cast<NodeT *>(A)),
+ getNode(const_cast<NodeT *>(B)));
+ }
+
+ NodeT *getRoot() const {
+ assert(this->Roots.size() == 1 && "Should always have entry node!");
+ return this->Roots[0];
+ }
+
+ /// findNearestCommonDominator - Find nearest common dominator basic block
+ /// for basic block A and B. If there is no such block then return NULL.
+ NodeT *findNearestCommonDominator(NodeT *A, NodeT *B) {
+ assert(A->getParent() == B->getParent() &&
+ "Two blocks are not in same function");
+
+ // If either A or B is a entry block then it is nearest common dominator
+ // (for forward-dominators).
+ if (!this->isPostDominator()) {
+ NodeT &Entry = A->getParent()->front();
+ if (A == &Entry || B == &Entry)
+ return &Entry;
}
- private:
- inline Node2(BasicBlock *node, Node *iDom)
- : TheNode(node), IDom(iDom) {}
- inline Node2 *addChild(Node *C) { Children.push_back(C); return C; }
+ // If B dominates A then B is nearest common dominator.
+ if (dominates(B, A))
+ return B;
- void setIDom(Node2 *NewIDom);
- };
+ // If A dominates B then A is nearest common dominator.
+ if (dominates(A, B))
+ return A;
-public:
- DominatorTreeBase(bool isPostDom) : DominatorBase(isPostDom) {}
- ~DominatorTreeBase() { reset(); }
+ DomTreeNodeBase<NodeT> *NodeA = getNode(A);
+ DomTreeNodeBase<NodeT> *NodeB = getNode(B);
- virtual void releaseMemory() { reset(); }
+ // Collect NodeA dominators set.
+ SmallPtrSet<DomTreeNodeBase<NodeT>*, 16> NodeADoms;
+ NodeADoms.insert(NodeA);
+ DomTreeNodeBase<NodeT> *IDomA = NodeA->getIDom();
+ while (IDomA) {
+ NodeADoms.insert(IDomA);
+ IDomA = IDomA->getIDom();
+ }
- /// getNode - return the (Post)DominatorTree node for the specified basic
- /// block. This is the same as using operator[] on this class.
- ///
- inline Node *getNode(BasicBlock *BB) const {
- NodeMapType::const_iterator i = Nodes.find(BB);
- return (i != Nodes.end()) ? i->second : 0;
+ // Walk NodeB immediate dominators chain and find common dominator node.
+ DomTreeNodeBase<NodeT> *IDomB = NodeB->getIDom();
+ while (IDomB) {
+ if (NodeADoms.count(IDomB) != 0)
+ return IDomB->getBlock();
+
+ IDomB = IDomB->getIDom();
+ }
+
+ return NULL;
}
- inline Node *operator[](BasicBlock *BB) const {
- return getNode(BB);
+ const NodeT *findNearestCommonDominator(const NodeT *A, const NodeT *B) {
+ // Cast away the const qualifiers here. This is ok since
+ // const is re-introduced on the return type.
+ return findNearestCommonDominator(const_cast<NodeT *>(A),
+ const_cast<NodeT *>(B));
}
- //===--------------------------------------------------------------------===// // API to update (Post)DominatorTree information based on modifications to
+ //===--------------------------------------------------------------------===//
+ // API to update (Post)DominatorTree information based on modifications to
// the CFG...
- /// createNewNode - Add a new node to the dominator tree information. This
- /// creates a new node as a child of IDomNode, linking it into the children
- /// list of the immediate dominator.
- ///
- Node *createNewNode(BasicBlock *BB, Node *IDomNode) {
+ /// addNewBlock - Add a new node to the dominator tree information. This
+ /// creates a new node as a child of DomBB dominator node,linking it into
+ /// the children list of the immediate dominator.
+ DomTreeNodeBase<NodeT> *addNewBlock(NodeT *BB, NodeT *DomBB) {
assert(getNode(BB) == 0 && "Block already in dominator tree!");
+ DomTreeNodeBase<NodeT> *IDomNode = getNode(DomBB);
assert(IDomNode && "Not immediate dominator specified for block!");
- return Nodes[BB] = IDomNode->addChild(new Node(BB, IDomNode));
+ DFSInfoValid = false;
+ return DomTreeNodes[BB] =
+ IDomNode->addChild(new DomTreeNodeBase<NodeT>(BB, IDomNode));
}
/// changeImmediateDominator - This method is used to update the dominator
/// tree information when a node's immediate dominator changes.
///
- void changeImmediateDominator(Node *Node, Node *NewIDom) {
- assert(Node && NewIDom && "Cannot change null node pointers!");
- Node->setIDom(NewIDom);
+ void changeImmediateDominator(DomTreeNodeBase<NodeT> *N,
+ DomTreeNodeBase<NodeT> *NewIDom) {
+ assert(N && NewIDom && "Cannot change null node pointers!");
+ DFSInfoValid = false;
+ N->setIDom(NewIDom);
+ }
+
+ void changeImmediateDominator(NodeT *BB, NodeT *NewBB) {
+ changeImmediateDominator(getNode(BB), getNode(NewBB));
+ }
+
+ /// eraseNode - Removes a node from the dominator tree. Block must not
+ /// dominate any other blocks. Removes node from its immediate dominator's
+ /// children list. Deletes dominator node associated with basic block BB.
+ void eraseNode(NodeT *BB) {
+ DomTreeNodeBase<NodeT> *Node = getNode(BB);
+ assert(Node && "Removing node that isn't in dominator tree.");
+ assert(Node->getChildren().empty() && "Node is not a leaf node.");
+
+ // Remove node from immediate dominator's children list.
+ DomTreeNodeBase<NodeT> *IDom = Node->getIDom();
+ if (IDom) {
+ typename std::vector<DomTreeNodeBase<NodeT>*>::iterator I =
+ std::find(IDom->Children.begin(), IDom->Children.end(), Node);
+ assert(I != IDom->Children.end() &&
+ "Not in immediate dominator children set!");
+ // I am no longer your child...
+ IDom->Children.erase(I);
+ }
+
+ DomTreeNodes.erase(BB);
+ delete Node;
+ }
+
+ /// removeNode - Removes a node from the dominator tree. Block must not
+ /// dominate any other blocks. Invalidates any node pointing to removed
+ /// block.
+ void removeNode(NodeT *BB) {
+ assert(getNode(BB) && "Removing node that isn't in dominator tree.");
+ DomTreeNodes.erase(BB);
+ }
+
+ /// splitBlock - BB is split and now it has one successor. Update dominator
+ /// tree to reflect this change.
+ void splitBlock(NodeT* NewBB) {
+ if (this->IsPostDominators)
+ this->Split<Inverse<NodeT*>, GraphTraits<Inverse<NodeT*> > >(*this, NewBB);
+ else
+ this->Split<NodeT*, GraphTraits<NodeT*> >(*this, NewBB);
}
/// print - Convert to human readable form
- virtual void print(std::ostream &OS) const;
+ ///
+ void print(raw_ostream &o) const {
+ o << "=============================--------------------------------\n";
+ if (this->isPostDominator())
+ o << "Inorder PostDominator Tree: ";
+ else
+ o << "Inorder Dominator Tree: ";
+ if (this->DFSInfoValid)
+ o << "DFSNumbers invalid: " << SlowQueries << " slow queries.";
+ o << "\n";
+
+ // The postdom tree can have a null root if there are no returns.
+ if (getRootNode())
+ PrintDomTree<NodeT>(getRootNode(), o, 1);
+ }
+
+protected:
+ template<class GraphT>
+ friend void Compress(DominatorTreeBase<typename GraphT::NodeType>& DT,
+ typename GraphT::NodeType* VIn);
+
+ template<class GraphT>
+ friend typename GraphT::NodeType* Eval(
+ DominatorTreeBase<typename GraphT::NodeType>& DT,
+ typename GraphT::NodeType* V);
+
+ template<class GraphT>
+ friend void Link(DominatorTreeBase<typename GraphT::NodeType>& DT,
+ unsigned DFSNumV, typename GraphT::NodeType* W,
+ typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &WInfo);
+
+ template<class GraphT>
+ friend unsigned DFSPass(DominatorTreeBase<typename GraphT::NodeType>& DT,
+ typename GraphT::NodeType* V,
+ unsigned N);
+
+ template<class FuncT, class N>
+ friend void Calculate(DominatorTreeBase<typename GraphTraits<N>::NodeType>& DT,
+ FuncT& F);
+
+ /// updateDFSNumbers - Assign In and Out numbers to the nodes while walking
+ /// dominator tree in dfs order.
+ void updateDFSNumbers() {
+ unsigned DFSNum = 0;
+
+ SmallVector<std::pair<DomTreeNodeBase<NodeT>*,
+ typename DomTreeNodeBase<NodeT>::iterator>, 32> WorkStack;
+
+ DomTreeNodeBase<NodeT> *ThisRoot = getRootNode();
+
+ if (!ThisRoot)
+ return;
+
+ // Even in the case of multiple exits that form the post dominator root
+ // nodes, do not iterate over all exits, but start from the virtual root
+ // node. Otherwise bbs, that are not post dominated by any exit but by the
+ // virtual root node, will never be assigned a DFS number.
+ WorkStack.push_back(std::make_pair(ThisRoot, ThisRoot->begin()));
+ ThisRoot->DFSNumIn = DFSNum++;
+
+ while (!WorkStack.empty()) {
+ DomTreeNodeBase<NodeT> *Node = WorkStack.back().first;
+ typename DomTreeNodeBase<NodeT>::iterator ChildIt =
+ WorkStack.back().second;
+
+ // If we visited all of the children of this node, "recurse" back up the
+ // stack setting the DFOutNum.
+ if (ChildIt == Node->end()) {
+ Node->DFSNumOut = DFSNum++;
+ WorkStack.pop_back();
+ } else {
+ // Otherwise, recursively visit this child.
+ DomTreeNodeBase<NodeT> *Child = *ChildIt;
+ ++WorkStack.back().second;
+
+ WorkStack.push_back(std::make_pair(Child, Child->begin()));
+ Child->DFSNumIn = DFSNum++;
+ }
+ }
+
+ SlowQueries = 0;
+ DFSInfoValid = true;
+ }
+
+ DomTreeNodeBase<NodeT> *getNodeForBlock(NodeT *BB) {
+ typename DomTreeNodeMapType::iterator I = this->DomTreeNodes.find(BB);
+ if (I != this->DomTreeNodes.end() && I->second)
+ return I->second;
+
+ // Haven't calculated this node yet? Get or calculate the node for the
+ // immediate dominator.
+ NodeT *IDom = getIDom(BB);
+
+ assert(IDom || this->DomTreeNodes[NULL]);
+ DomTreeNodeBase<NodeT> *IDomNode = getNodeForBlock(IDom);
+
+ // Add a new tree node for this BasicBlock, and link it as a child of
+ // IDomNode
+ DomTreeNodeBase<NodeT> *C = new DomTreeNodeBase<NodeT>(BB, IDomNode);
+ return this->DomTreeNodes[BB] = IDomNode->addChild(C);
+ }
+
+ inline NodeT *getIDom(NodeT *BB) const {
+ typename DenseMap<NodeT*, NodeT*>::const_iterator I = IDoms.find(BB);
+ return I != IDoms.end() ? I->second : 0;
+ }
+
+ inline void addRoot(NodeT* BB) {
+ this->Roots.push_back(BB);
+ }
+
+public:
+ /// recalculate - compute a dominator tree for the given function
+ template<class FT>
+ void recalculate(FT& F) {
+ reset();
+ this->Vertex.push_back(0);
+
+ if (!this->IsPostDominators) {
+ // Initialize root
+ this->Roots.push_back(&F.front());
+ this->IDoms[&F.front()] = 0;
+ this->DomTreeNodes[&F.front()] = 0;
+
+ Calculate<FT, NodeT*>(*this, F);
+ } else {
+ // Initialize the roots list
+ for (typename FT::iterator I = F.begin(), E = F.end(); I != E; ++I) {
+ if (std::distance(GraphTraits<FT*>::child_begin(I),
+ GraphTraits<FT*>::child_end(I)) == 0)
+ addRoot(I);
+
+ // Prepopulate maps so that we don't get iterator invalidation issues later.
+ this->IDoms[I] = 0;
+ this->DomTreeNodes[I] = 0;
+ }
+
+ Calculate<FT, Inverse<NodeT*> >(*this, F);
+ }
+ }
};
+EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<BasicBlock>);
//===-------------------------------------
-// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
-// compute a normal dominator tree.
-//
-struct DominatorTree : public DominatorTreeBase {
- DominatorTree() : DominatorTreeBase(false) {}
-
- virtual bool runOnFunction(Function &F) {
- reset(); // Reset from the last time we were run...
- DominatorSet &DS = getAnalysis<DominatorSet>();
- Root = DS.getRoot();
- calculate(DS);
+/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
+/// compute a normal dominator tree.
+///
+class DominatorTree : public FunctionPass {
+public:
+ static char ID; // Pass ID, replacement for typeid
+ DominatorTreeBase<BasicBlock>* DT;
+
+ DominatorTree() : FunctionPass(ID) {
+ initializeDominatorTreePass(*PassRegistry::getPassRegistry());
+ DT = new DominatorTreeBase<BasicBlock>(false);
+ }
+
+ ~DominatorTree() {
+ delete DT;
+ }
+
+ DominatorTreeBase<BasicBlock>& getBase() { return *DT; }
+
+ /// getRoots - Return the root blocks of the current CFG. This may include
+ /// multiple blocks if we are computing post dominators. For forward
+ /// dominators, this will always be a single block (the entry node).
+ ///
+ inline const std::vector<BasicBlock*> &getRoots() const {
+ return DT->getRoots();
+ }
+
+ inline BasicBlock *getRoot() const {
+ return DT->getRoot();
+ }
+
+ inline DomTreeNode *getRootNode() const {
+ return DT->getRootNode();
+ }
+
+ /// compare - Return false if the other dominator tree matches this
+ /// dominator tree. Otherwise return true.
+ inline bool compare(DominatorTree &Other) const {
+ DomTreeNode *R = getRootNode();
+ DomTreeNode *OtherR = Other.getRootNode();
+
+ if (!R || !OtherR || R->getBlock() != OtherR->getBlock())
+ return true;
+
+ if (DT->compare(Other.getBase()))
+ return true;
+
return false;
}
+ virtual bool runOnFunction(Function &F);
+
+ virtual void verifyAnalysis() const;
+
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
- AU.addRequired<DominatorSet>();
}
-private:
- void calculate(const DominatorSet &DS);
+
+ inline bool dominates(DomTreeNode* A, DomTreeNode* B) const {
+ return DT->dominates(A, B);
+ }
+
+ inline bool dominates(const BasicBlock* A, const BasicBlock* B) const {
+ return DT->dominates(A, B);
+ }
+
+ // dominates - Return true if A dominates B. This performs the
+ // special checks necessary if A and B are in the same basic block.
+ bool dominates(const Instruction *A, const Instruction *B) const;
+
+ bool properlyDominates(const DomTreeNode *A, const DomTreeNode *B) const {
+ return DT->properlyDominates(A, B);
+ }
+
+ bool properlyDominates(const BasicBlock *A, const BasicBlock *B) const {
+ return DT->properlyDominates(A, B);
+ }
+
+ /// findNearestCommonDominator - Find nearest common dominator basic block
+ /// for basic block A and B. If there is no such block then return NULL.
+ inline BasicBlock *findNearestCommonDominator(BasicBlock *A, BasicBlock *B) {
+ return DT->findNearestCommonDominator(A, B);
+ }
+
+ inline const BasicBlock *findNearestCommonDominator(const BasicBlock *A,
+ const BasicBlock *B) {
+ return DT->findNearestCommonDominator(A, B);
+ }
+
+ inline DomTreeNode *operator[](BasicBlock *BB) const {
+ return DT->getNode(BB);
+ }
+
+ /// getNode - return the (Post)DominatorTree node for the specified basic
+ /// block. This is the same as using operator[] on this class.
+ ///
+ inline DomTreeNode *getNode(BasicBlock *BB) const {
+ return DT->getNode(BB);
+ }
+
+ /// addNewBlock - Add a new node to the dominator tree information. This
+ /// creates a new node as a child of DomBB dominator node,linking it into
+ /// the children list of the immediate dominator.
+ inline DomTreeNode *addNewBlock(BasicBlock *BB, BasicBlock *DomBB) {
+ return DT->addNewBlock(BB, DomBB);
+ }
+
+ /// changeImmediateDominator - This method is used to update the dominator
+ /// tree information when a node's immediate dominator changes.
+ ///
+ inline void changeImmediateDominator(BasicBlock *N, BasicBlock* NewIDom) {
+ DT->changeImmediateDominator(N, NewIDom);
+ }
+
+ inline void changeImmediateDominator(DomTreeNode *N, DomTreeNode* NewIDom) {
+ DT->changeImmediateDominator(N, NewIDom);
+ }
+
+ /// eraseNode - Removes a node from the dominator tree. Block must not
+ /// dominate any other blocks. Removes node from its immediate dominator's
+ /// children list. Deletes dominator node associated with basic block BB.
+ inline void eraseNode(BasicBlock *BB) {
+ DT->eraseNode(BB);
+ }
+
+ /// splitBlock - BB is split and now it has one successor. Update dominator
+ /// tree to reflect this change.
+ inline void splitBlock(BasicBlock* NewBB) {
+ DT->splitBlock(NewBB);
+ }
+
+ bool isReachableFromEntry(const BasicBlock* A) {
+ return DT->isReachableFromEntry(A);
+ }
+
+
+ virtual void releaseMemory() {
+ DT->releaseMemory();
+ }
+
+ virtual void print(raw_ostream &OS, const Module* M= 0) const;
};
//===-------------------------------------
-// DominatorTree GraphTraits specialization so the DominatorTree can be
-// iterable by generic graph iterators.
-
-template <> struct GraphTraits<DominatorTree::Node*> {
- typedef DominatorTree::Node NodeType;
+/// DominatorTree GraphTraits specialization so the DominatorTree can be
+/// iterable by generic graph iterators.
+///
+template <> struct GraphTraits<DomTreeNode*> {
+ typedef DomTreeNode NodeType;
typedef NodeType::iterator ChildIteratorType;
static NodeType *getEntryNode(NodeType *N) {
return N;
}
- static inline ChildIteratorType child_begin(NodeType* N) {
+ static inline ChildIteratorType child_begin(NodeType *N) {
return N->begin();
}
- static inline ChildIteratorType child_end(NodeType* N) {
+ static inline ChildIteratorType child_end(NodeType *N) {
return N->end();
}
+
+ typedef df_iterator<DomTreeNode*> nodes_iterator;
+
+ static nodes_iterator nodes_begin(DomTreeNode *N) {
+ return df_begin(getEntryNode(N));
+ }
+
+ static nodes_iterator nodes_end(DomTreeNode *N) {
+ return df_end(getEntryNode(N));
+ }
};
template <> struct GraphTraits<DominatorTree*>
- : public GraphTraits<DominatorTree::Node*> {
+ : public GraphTraits<DomTreeNode*> {
static NodeType *getEntryNode(DominatorTree *DT) {
- return DT->getNode(DT->getRoot());
+ return DT->getRootNode();
+ }
+
+ static nodes_iterator nodes_begin(DominatorTree *N) {
+ return df_begin(getEntryNode(N));
+ }
+
+ static nodes_iterator nodes_end(DominatorTree *N) {
+ return df_end(getEntryNode(N));
}
};
+
//===----------------------------------------------------------------------===//
-//
-// DominanceFrontier - Calculate the dominance frontiers for a function.
-//
-class DominanceFrontierBase : public DominatorBase {
+/// DominanceFrontierBase - Common base class for computing forward and inverse
+/// dominance frontiers for a function.
+///
+class DominanceFrontierBase : public FunctionPass {
public:
typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
typedef std::map<BasicBlock*, DomSetType> DomSetMapType; // Dom set map
protected:
DomSetMapType Frontiers;
+ std::vector<BasicBlock*> Roots;
+ const bool IsPostDominators;
+
public:
- DominanceFrontierBase(bool isPostDom) : DominatorBase(isPostDom) {}
+ DominanceFrontierBase(char &ID, bool isPostDom)
+ : FunctionPass(ID), IsPostDominators(isPostDom) {}
+
+ /// getRoots - Return the root blocks of the current CFG. This may include
+ /// multiple blocks if we are computing post dominators. For forward
+ /// dominators, this will always be a single block (the entry node).
+ ///
+ inline const std::vector<BasicBlock*> &getRoots() const { return Roots; }
+
+ /// isPostDominator - Returns true if analysis based of postdoms
+ ///
+ bool isPostDominator() const { return IsPostDominators; }
virtual void releaseMemory() { Frontiers.clear(); }
iterator find(BasicBlock *B) { return Frontiers.find(B); }
const_iterator find(BasicBlock *B) const { return Frontiers.find(B); }
- void addBasicBlock(BasicBlock *BB, const DomSetType &frontier) {
+ iterator addBasicBlock(BasicBlock *BB, const DomSetType &frontier) {
assert(find(BB) == end() && "Block already in DominanceFrontier!");
- Frontiers.insert(std::make_pair(BB, frontier));
+ return Frontiers.insert(std::make_pair(BB, frontier)).first;
+ }
+
+ /// removeBlock - Remove basic block BB's frontier.
+ void removeBlock(BasicBlock *BB) {
+ assert(find(BB) != end() && "Block is not in DominanceFrontier!");
+ for (iterator I = begin(), E = end(); I != E; ++I)
+ I->second.erase(BB);
+ Frontiers.erase(BB);
}
void addToFrontier(iterator I, BasicBlock *Node) {
I->second.erase(Node);
}
- // print - Convert to human readable form
- virtual void print(std::ostream &OS) const;
+ /// compareDomSet - Return false if two domsets match. Otherwise
+ /// return true;
+ bool compareDomSet(DomSetType &DS1, const DomSetType &DS2) const {
+ std::set<BasicBlock *> tmpSet;
+ for (DomSetType::const_iterator I = DS2.begin(),
+ E = DS2.end(); I != E; ++I)
+ tmpSet.insert(*I);
+
+ for (DomSetType::const_iterator I = DS1.begin(),
+ E = DS1.end(); I != E; ) {
+ BasicBlock *Node = *I++;
+
+ if (tmpSet.erase(Node) == 0)
+ // Node is in DS1 but not in DS2.
+ return true;
+ }
+
+ if (!tmpSet.empty())
+ // There are nodes that are in DS2 but not in DS1.
+ return true;
+
+ // DS1 and DS2 matches.
+ return false;
+ }
+
+ /// compare - Return true if the other dominance frontier base matches
+ /// this dominance frontier base. Otherwise return false.
+ bool compare(DominanceFrontierBase &Other) const {
+ DomSetMapType tmpFrontiers;
+ for (DomSetMapType::const_iterator I = Other.begin(),
+ E = Other.end(); I != E; ++I)
+ tmpFrontiers.insert(std::make_pair(I->first, I->second));
+
+ for (DomSetMapType::iterator I = tmpFrontiers.begin(),
+ E = tmpFrontiers.end(); I != E; ) {
+ BasicBlock *Node = I->first;
+ const_iterator DFI = find(Node);
+ if (DFI == end())
+ return true;
+
+ if (compareDomSet(I->second, DFI->second))
+ return true;
+
+ ++I;
+ tmpFrontiers.erase(Node);
+ }
+
+ if (!tmpFrontiers.empty())
+ return true;
+
+ return false;
+ }
+
+ /// print - Convert to human readable form
+ ///
+ virtual void print(raw_ostream &OS, const Module* = 0) const;
+
+ /// dump - Dump the dominance frontier to dbgs().
+ void dump() const;
};
//===-------------------------------------
-// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
-// compute a normal dominator tree.
-//
-struct DominanceFrontier : public DominanceFrontierBase {
- DominanceFrontier() : DominanceFrontierBase(false) {}
+/// DominanceFrontier Class - Concrete subclass of DominanceFrontierBase that is
+/// used to compute a forward dominator frontiers.
+///
+class DominanceFrontier : public DominanceFrontierBase {
+public:
+ static char ID; // Pass ID, replacement for typeid
+ DominanceFrontier() :
+ DominanceFrontierBase(ID, false) {
+ initializeDominanceFrontierPass(*PassRegistry::getPassRegistry());
+ }
+
+ BasicBlock *getRoot() const {
+ assert(Roots.size() == 1 && "Should always have entry node!");
+ return Roots[0];
+ }
virtual bool runOnFunction(Function &) {
Frontiers.clear();
DominatorTree &DT = getAnalysis<DominatorTree>();
- Root = DT.getRoot();
- calculate(DT, DT[Root]);
+ Roots = DT.getRoots();
+ assert(Roots.size() == 1 && "Only one entry block for forward domfronts!");
+ calculate(DT, DT[Roots[0]]);
return false;
}
+ virtual void verifyAnalysis() const;
+
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<DominatorTree>();
}
-private:
+
+ /// splitBlock - BB is split and now it has one successor. Update dominance
+ /// frontier to reflect this change.
+ void splitBlock(BasicBlock *BB);
+
+ /// BasicBlock BB's new dominator is NewBB. Update BB's dominance frontier
+ /// to reflect this change.
+ void changeImmediateDominator(BasicBlock *BB, BasicBlock *NewBB,
+ DominatorTree *DT) {
+ // NewBB is now dominating BB. Which means BB's dominance
+ // frontier is now part of NewBB's dominance frontier. However, BB
+ // itself is not member of NewBB's dominance frontier.
+ DominanceFrontier::iterator NewDFI = find(NewBB);
+ DominanceFrontier::iterator DFI = find(BB);
+ // If BB was an entry block then its frontier is empty.
+ if (DFI == end())
+ return;
+ DominanceFrontier::DomSetType BBSet = DFI->second;
+ for (DominanceFrontier::DomSetType::iterator BBSetI = BBSet.begin(),
+ BBSetE = BBSet.end(); BBSetI != BBSetE; ++BBSetI) {
+ BasicBlock *DFMember = *BBSetI;
+ // Insert only if NewBB dominates DFMember.
+ if (!DT->dominates(NewBB, DFMember))
+ NewDFI->second.insert(DFMember);
+ }
+ NewDFI->second.erase(BB);
+ }
+
const DomSetType &calculate(const DominatorTree &DT,
- const DominatorTree::Node *Node);
+ const DomTreeNode *Node);
};
+
+} // End llvm namespace
+
#endif
projects / oota-llvm.git / blobdiff