//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the following classes:
-// 1. DominatorTree: Represent the ImmediateDominator as an explicit tree
-// structure.
-// 2. ETForest: Efficient data structure for dominance comparisons and
-// nearest-common-ancestor queries.
-// 3. 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.
+// DominatorTree mapping.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_DOMINATORS_H
#define LLVM_ANALYSIS_DOMINATORS_H
-#include "llvm/Analysis/ET-Forest.h"
#include "llvm/Pass.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/ADT/DenseMap.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 <algorithm>
+#include <map>
#include <set>
namespace llvm {
-class Instruction;
-
-template <typename GraphType> struct GraphTraits;
-
//===----------------------------------------------------------------------===//
/// DominatorBase - Base class that other, more interesting dominator analyses
/// inherit from.
///
-class DominatorBase : public FunctionPass {
+template <class NodeT>
+class DominatorBase {
protected:
- std::vector<BasicBlock*> Roots;
+ std::vector<NodeT*> Roots;
const bool IsPostDominators;
- inline DominatorBase(intptr_t ID, bool isPostDom) :
- FunctionPass(ID), Roots(), IsPostDominators(isPostDom) {}
+ inline explicit DominatorBase(bool isPostDom) :
+ Roots(), IsPostDominators(isPostDom) {}
public:
/// 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; }
+ inline const std::vector<NodeT*> &getRoots() const { return Roots; }
/// isPostDominator - Returns true if analysis based of postdoms
///
bool isPostDominator() const { return IsPostDominators; }
};
+
+//===----------------------------------------------------------------------===//
+// 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:
+ 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) { }
+
+ DomTreeNodeBase<NodeT> *addChild(DomTreeNodeBase<NodeT> *C) {
+ Children.push_back(C);
+ return C;
+ }
+
+ size_t getNumChildren() const {
+ return Children.size();
+ }
+
+ void clearAllChildren() {
+ Children.clear();
+ }
+
+ bool compare(DomTreeNodeBase<NodeT> *Other) {
+ if (getNumChildren() != Other->getNumChildren())
+ return true;
+
+ SmallPtrSet<NodeT *, 4> OtherChildren;
+ for(iterator I = Other->begin(), E = Other->end(); I != E; ++I) {
+ NodeT *Nd = (*I)->getBlock();
+ OtherChildren.insert(Nd);
+ }
+
+ for(iterator I = begin(), E = end(); I != E; ++I) {
+ NodeT *N = (*I)->getBlock();
+ if (OtherChildren.count(N) == 0)
+ return true;
+ }
+ return false;
+ }
+
+ 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);
+ }
+ }
+
+ /// 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>);
+
+template<class NodeT>
+static std::ostream &operator<<(std::ostream &o,
+ const DomTreeNodeBase<NodeT> *Node) {
+ if (Node->getBlock())
+ WriteAsOperand(o, Node->getBlock(), false);
+ else
+ o << " <<exit node>>";
+
+ o << " {" << Node->getDFSNumIn() << "," << Node->getDFSNumOut() << "}";
+
+ return o << "\n";
+}
+
+template<class NodeT>
+static void PrintDomTree(const DomTreeNodeBase<NodeT> *N, std::ostream &o,
+ unsigned Lev) {
+ o << std::string(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;
+
//===----------------------------------------------------------------------===//
/// DominatorTree - Calculate the immediate dominator tree for a function.
///
-class DominatorTreeBase : public DominatorBase {
-public:
- class Node;
-protected:
- std::map<BasicBlock*, Node*> Nodes;
- void reset();
- typedef std::map<BasicBlock*, Node*> NodeMapType;
- Node *RootNode;
+template<class FuncT, class N>
+void Calculate(DominatorTreeBase<typename GraphTraits<N>::NodeType>& DT,
+ FuncT& F);
+template<class NodeT>
+class DominatorTreeBase : public DominatorBase<NodeT> {
+protected:
+ 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;
- BasicBlock *Label, *Parent, *Child, *Ancestor;
+ NodeT *Label, *Child;
+ unsigned Parent, Ancestor;
- std::vector<BasicBlock*> Bucket;
+ std::vector<NodeT*> Bucket;
- InfoRec() : Semi(0), Size(0), Label(0), Parent(0), Child(0), Ancestor(0){}
+ InfoRec() : DFSNum(0), Semi(0), Size(0), Label(0), Child(0), Parent(0),
+ Ancestor(0) {}
};
- std::map<BasicBlock*, BasicBlock*> IDoms;
+ DenseMap<NodeT*, NodeT*> IDoms;
// Vertex - Map the DFS number to the BasicBlock*
- std::vector<BasicBlock*> Vertex;
+ std::vector<NodeT*> Vertex;
// Info - Collection of information used during the computation of idoms.
- std::map<BasicBlock*, InfoRec> Info;
+ 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;
+ for (typename GraphTraits<Inverse<N> >::ChildIteratorType PI =
+ GraphTraits<Inverse<N> >::child_begin(NewBB),
+ PE = GraphTraits<Inverse<N> >::child_end(NewBB); PI != PE; ++PI)
+ PredBlocks.push_back(*PI);
+
+ assert(!PredBlocks.empty() && "No predblocks??");
+
+ bool NewBBDominatesNewBBSucc = true;
+ for (typename GraphTraits<Inverse<N> >::ChildIteratorType PI =
+ GraphTraits<Inverse<N> >::child_begin(NewBBSucc),
+ E = GraphTraits<Inverse<N> >::child_end(NewBBSucc); PI != E; ++PI)
+ if (*PI != NewBB && !DT.dominates(NewBBSucc, *PI) &&
+ DT.isReachableFromEntry(*PI)) {
+ NewBBDominatesNewBBSucc = false;
+ break;
+ }
-public:
- class Node {
- friend class DominatorTree;
- friend struct PostDominatorTree;
- friend class DominatorTreeBase;
- BasicBlock *TheBB;
- Node *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 *getBlock() const { return TheBB; }
- inline Node *getIDom() const { return IDom; }
- inline const std::vector<Node*> &getChildren() const { return Children; }
-
- /// properlyDominates - Returns true iff this dominates N and this != N.
- /// Note that this is not a constant time operation!
- ///
- bool properlyDominates(const Node *N) const {
- const Node *IDom;
- if (this == 0 || N == 0) return false;
- while ((IDom = N->getIDom()) != 0 && IDom != this)
- N = IDom; // Walk up the tree
- return IDom != 0;
- }
+ // 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;
- /// dominates - Returns true iff this dominates N. Note that this is not a
- /// constant time operation!
- ///
- inline bool dominates(const Node *N) const {
- if (N == this) return true; // A node trivially dominates itself.
- return properlyDominates(N);
+ for (i = i + 1; i < PredBlocks.size(); ++i) {
+ if (DT.isReachableFromEntry(PredBlocks[i]))
+ NewBBIDom = DT.findNearestCommonDominator(NewBBIDom, PredBlocks[i]);
}
-
- private:
- inline Node(BasicBlock *BB, Node *iDom) : TheBB(BB), IDom(iDom) {}
- inline Node *addChild(Node *C) { Children.push_back(C); return C; }
- void setIDom(Node *NewIDom);
- };
+ // 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:
- DominatorTreeBase(intptr_t ID, bool isPostDom)
- : DominatorBase(ID, isPostDom) {}
- ~DominatorTreeBase() { reset(); }
+ 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;
+
+ SmallPtrSet<const NodeT *,4> MyBBs;
+ 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;
+ }
+
+ return false;
+ }
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 Node *getNode(BasicBlock *BB) const {
- NodeMapType::const_iterator i = Nodes.find(BB);
- return (i != Nodes.end()) ? i->second : 0;
- }
-
- inline Node *operator[](BasicBlock *BB) const {
- return getNode(BB);
+ inline DomTreeNodeBase<NodeT> *getNode(NodeT *BB) const {
+ typename DomTreeNodeMapType::const_iterator I = DomTreeNodes.find(BB);
+ return I != DomTreeNodes.end() ? I->second : 0;
}
/// getRootNode - This returns the entry node for the CFG of the function. If
/// post-dominance information must be capable of dealing with this
/// possibility.
///
- Node *getRootNode() { return RootNode; }
- const Node *getRootNode() const { return RootNode; }
+ DomTreeNodeBase<NodeT> *getRootNode() { return RootNode; }
+ const DomTreeNodeBase<NodeT> *getRootNode() const { return RootNode; }
+
+ /// properlyDominates - Returns true iff this dominates N and this != N.
+ /// Note that this is not a constant time operation!
+ ///
+ bool properlyDominates(const DomTreeNodeBase<NodeT> *A,
+ DomTreeNodeBase<NodeT> *B) const {
+ if (A == 0 || B == 0) return false;
+ return dominatedBySlowTreeWalk(A, B);
+ }
+
+ inline bool properlyDominates(NodeT *A, NodeT *B) {
+ return properlyDominates(getNode(A), getNode(B));
+ }
+
+ 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;
+ }
+
+
+ /// isReachableFromEntry - Return true if A is dominated by the entry
+ /// block of the function containing it.
+ bool isReachableFromEntry(NodeT* A) {
+ assert (!this->isPostDominator()
+ && "This is not implemented for post dominators");
+ return dominates(&A->getParent()->front(), A);
+ }
+
+ /// dominates - Returns true iff A dominates B. Note that this is not a
+ /// constant time operation!
+ ///
+ inline bool dominates(const DomTreeNodeBase<NodeT> *A,
+ DomTreeNodeBase<NodeT> *B) {
+ if (B == A)
+ return true; // A node trivially dominates itself.
+
+ if (A == 0 || B == 0)
+ return false;
+
+ 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(NodeT *A, NodeT *B) {
+ if (A == B)
+ return true;
+
+ return dominates(getNode(A), getNode(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 (!this->isPostDominator()
+ && "This is not implemented for post dominators");
+ 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.
+ NodeT &Entry = A->getParent()->front();
+ if (A == &Entry || B == &Entry)
+ return &Entry;
+
+ // If B dominates A then B is nearest common dominator.
+ if (dominates(B, A))
+ return B;
+
+ // If A dominates B then A is nearest common dominator.
+ if (dominates(A, B))
+ return A;
+
+ DomTreeNodeBase<NodeT> *NodeA = getNode(A);
+ DomTreeNodeBase<NodeT> *NodeB = getNode(B);
+
+ // 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();
+ }
+
+ // 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;
+ }
//===--------------------------------------------------------------------===//
// 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 *N, Node *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
+ /// domiante 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(BasicBlock *BB) {
+ void removeNode(NodeT *BB) {
assert(getNode(BB) && "Removing node that isn't in dominator tree.");
- Nodes.erase(BB);
+ 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 Module* = 0) const;
+ virtual void print(std::ostream &o, const Module* ) 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";
+
+ PrintDomTree<NodeT>(getRootNode(), o, 1);
+ }
+
void print(std::ostream *OS, const Module* M = 0) const {
if (OS) print(*OS, M);
}
-};
-
-//===-------------------------------------
-/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
-/// compute a normal dominator tree.
-///
-class DominatorTree : public DominatorTreeBase {
-public:
- static const char ID; // Pass ID, replacement for typeid
- DominatorTree() : DominatorTreeBase((intptr_t)&ID, false) {}
- BasicBlock *getRoot() const {
- assert(Roots.size() == 1 && "Should always have entry node!");
- return Roots[0];
+ virtual void dump() {
+ print(llvm::cerr);
}
- virtual bool runOnFunction(Function &F);
+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);
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesAll();
- }
-private:
- void calculate(Function& F);
- Node *getNodeForBlock(BasicBlock *BB);
- unsigned DFSPass(BasicBlock *V, InfoRec &VInfo, unsigned N);
- void Compress(BasicBlock *V, InfoRec &VInfo);
- BasicBlock *Eval(BasicBlock *v);
- void Link(BasicBlock *V, BasicBlock *W, InfoRec &WInfo);
- inline BasicBlock *getIDom(BasicBlock *BB) const {
- std::map<BasicBlock*, BasicBlock*>::const_iterator I = IDoms.find(BB);
- return I != IDoms.end() ? I->second : 0;
+ 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;
+
+ for (unsigned i = 0, e = (unsigned)this->Roots.size(); i != e; ++i) {
+ DomTreeNodeBase<NodeT> *ThisRoot = getNode(this->Roots[i]);
+ 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++;
+ }
+ }
}
-};
-
-//===-------------------------------------
-/// DominatorTree GraphTraits specialization so the DominatorTree can be
-/// iterable by generic graph iterators.
-///
-template <> struct GraphTraits<DominatorTree::Node*> {
- typedef DominatorTree::Node NodeType;
- typedef NodeType::iterator ChildIteratorType;
+
+ SlowQueries = 0;
+ DFSInfoValid = true;
+ }
- static NodeType *getEntryNode(NodeType *N) {
- return N;
+ DomTreeNodeBase<NodeT> *getNodeForBlock(NodeT *BB) {
+ if (DomTreeNodeBase<NodeT> *BBNode = this->DomTreeNodes[BB])
+ return BBNode;
+
+ // 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);
}
- static inline ChildIteratorType child_begin(NodeType* N) {
- return N->begin();
+
+ inline NodeT *getIDom(NodeT *BB) const {
+ typename DenseMap<NodeT*, NodeT*>::const_iterator I = IDoms.find(BB);
+ return I != IDoms.end() ? I->second : 0;
}
- static inline ChildIteratorType child_end(NodeType* N) {
- return N->end();
+
+ 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) {
+ if (!this->IsPostDominators) {
+ reset();
+
+ // Initialize roots
+ this->Roots.push_back(&F.front());
+ this->IDoms[&F.front()] = 0;
+ this->DomTreeNodes[&F.front()] = 0;
+ this->Vertex.push_back(0);
+
+ Calculate<FT, NodeT*>(*this, F);
+
+ updateDFSNumbers();
+ } else {
+ reset(); // Reset from the last time we were run...
+
+ // 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;
+ }
-template <> struct GraphTraits<DominatorTree*>
- : public GraphTraits<DominatorTree::Node*> {
- static NodeType *getEntryNode(DominatorTree *DT) {
- return DT->getRootNode();
+ this->Vertex.push_back(0);
+
+ Calculate<FT, Inverse<NodeT*> >(*this, F);
+ }
}
};
+EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<BasicBlock>);
//===-------------------------------------
-/// ET-Forest Class - Class used to construct forwards and backwards
-/// ET-Forests
+/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
+/// compute a normal dominator tree.
///
-class ETForestBase : public DominatorBase {
+class DominatorTree : public FunctionPass {
public:
- ETForestBase(intptr_t ID, bool isPostDom)
- : DominatorBase(ID, isPostDom), Nodes(),
- DFSInfoValid(false), SlowQueries(0) {}
+ static char ID; // Pass ID, replacement for typeid
+ DominatorTreeBase<BasicBlock>* DT;
- virtual void releaseMemory() { reset(); }
-
- typedef std::map<BasicBlock*, ETNode*> ETMapType;
+ DominatorTree() : FunctionPass(&ID) {
+ DT = new DominatorTreeBase<BasicBlock>(false);
+ }
+
+ ~DominatorTree() {
+ DT->releaseMemory();
+ 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();
+ }
- void updateDFSNumbers();
+ /// 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();
- /// dominates - Return true if A dominates B.
- ///
- inline bool dominates(BasicBlock *A, BasicBlock *B) {
- if (A == B)
+ if (!R || !OtherR || R->getBlock() != OtherR->getBlock())
return true;
- ETNode *NodeA = getNode(A);
- ETNode *NodeB = getNode(B);
-
- if (DFSInfoValid)
- return NodeB->DominatedBy(NodeA);
- else {
- // 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 NodeB->DominatedBy(NodeA);
- }
- return NodeB->DominatedBySlow(NodeA);
- }
+ if (DT->compare(Other.getBase()))
+ return true;
+
+ return false;
}
+ virtual bool runOnFunction(Function &F);
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ }
+
+ inline bool dominates(DomTreeNode* A, DomTreeNode* B) const {
+ return DT->dominates(A, B);
+ }
+
+ inline bool dominates(BasicBlock* A, 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(Instruction *A, Instruction *B);
-
- /// properlyDominates - Return true if A dominates B and A != B.
- ///
- bool properlyDominates(BasicBlock *A, BasicBlock *B) {
- return dominates(A, B) && A != B;
+ bool dominates(Instruction *A, Instruction *B) const {
+ BasicBlock *BBA = A->getParent(), *BBB = B->getParent();
+ if (BBA != BBB) return DT->dominates(BBA, BBB);
+
+ // It is not possible to determine dominance between two PHI nodes
+ // based on their ordering.
+ if (isa<PHINode>(A) && isa<PHINode>(B))
+ return false;
+
+ // Loop through the basic block until we find A or B.
+ BasicBlock::iterator I = BBA->begin();
+ for (; &*I != A && &*I != B; ++I) /*empty*/;
+
+ //if(!DT.IsPostDominators) {
+ // A dominates B if it is found first in the basic block.
+ return &*I == A;
+ //} else {
+ // // A post-dominates B if B is found first in the basic block.
+ // return &*I == B;
+ //}
}
-
- /// isReachableFromEntry - Return true if A is dominated by the entry
- /// block of the function containing it.
- const bool isReachableFromEntry(BasicBlock* A);
- /// Return the nearest common dominator of A and B.
- BasicBlock *nearestCommonDominator(BasicBlock *A, BasicBlock *B) const {
- ETNode *NodeA = getNode(A);
- ETNode *NodeB = getNode(B);
-
- ETNode *Common = NodeA->NCA(NodeB);
- if (!Common)
- return NULL;
- return Common->getData<BasicBlock>();
+ inline bool properlyDominates(const DomTreeNode* A, DomTreeNode* B) const {
+ return DT->properlyDominates(A, B);
}
- /// Return the immediate dominator of A.
- BasicBlock *getIDom(BasicBlock *A) const {
- ETNode *NodeA = getNode(A);
- if (!NodeA) return 0;
- const ETNode *idom = NodeA->getFather();
- return idom ? idom->getData<BasicBlock>() : 0;
+ inline bool properlyDominates(BasicBlock* A, BasicBlock* B) const {
+ return DT->properlyDominates(A, B);
}
- void getChildren(BasicBlock *A, std::vector<BasicBlock*>& children) const {
- ETNode *NodeA = getNode(A);
- if (!NodeA) return;
- const ETNode* son = NodeA->getSon();
-
- if (!son) return;
- children.push_back(son->getData<BasicBlock>());
-
- const ETNode* brother = son->getBrother();
- while (brother != son) {
- children.push_back(brother->getData<BasicBlock>());
- brother = brother->getBrother();
- }
+ /// 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);
}
-
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesAll();
- AU.addRequired<DominatorTree>();
- }
- //===--------------------------------------------------------------------===//
- // API to update Forest information based on modifications
- // to the CFG...
-
- /// addNewBlock - Add a new block to the CFG, with the specified immediate
- /// dominator.
- ///
- void addNewBlock(BasicBlock *BB, BasicBlock *IDom);
-
- /// setImmediateDominator - Update the immediate dominator information to
- /// change the current immediate dominator for the specified block
- /// to another block. This method requires that BB for NewIDom
- /// already have an ETNode, otherwise just use addNewBlock.
- ///
- void setImmediateDominator(BasicBlock *BB, BasicBlock *NewIDom);
- /// print - Convert to human readable form
- ///
- virtual void print(std::ostream &OS, const Module* = 0) const;
- void print(std::ostream *OS, const Module* M = 0) const {
- if (OS) print(*OS, M);
+
+ inline DomTreeNode *operator[](BasicBlock *BB) const {
+ return DT->getNode(BB);
}
-protected:
+
/// getNode - return the (Post)DominatorTree node for the specified basic
/// block. This is the same as using operator[] on this class.
///
- inline ETNode *getNode(BasicBlock *BB) const {
- ETMapType::const_iterator i = Nodes.find(BB);
- return (i != Nodes.end()) ? i->second : 0;
+ inline DomTreeNode *getNode(BasicBlock *BB) const {
+ return DT->getNode(BB);
}
-
- inline ETNode *operator[](BasicBlock *BB) const {
- return 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
+ /// domiante 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(BasicBlock* A) {
+ return DT->isReachableFromEntry(A);
+ }
+
+
+ virtual void releaseMemory() {
+ DT->releaseMemory();
+ }
+
+ virtual void print(std::ostream &OS, const Module* M= 0) const {
+ DT->print(OS, M);
}
-
- void reset();
- ETMapType Nodes;
- bool DFSInfoValid;
- unsigned int SlowQueries;
-
};
-//==-------------------------------------
-/// ETForest Class - Concrete subclass of ETForestBase that is used to
-/// compute a forwards ET-Forest.
-
-class ETForest : public ETForestBase {
-public:
- static const char ID; // Pass identifcation, replacement for typeid
-
- ETForest() : ETForestBase((intptr_t)&ID, false) {}
-
- BasicBlock *getRoot() const {
- assert(Roots.size() == 1 && "Should always have entry node!");
- return Roots[0];
+//===-------------------------------------
+/// 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;
}
-
- virtual bool runOnFunction(Function &F) {
- reset(); // Reset from the last time we were run...
- DominatorTree &DT = getAnalysis<DominatorTree>();
- Roots = DT.getRoots();
- calculate(DT);
- return false;
+ static inline ChildIteratorType child_begin(NodeType* N) {
+ return N->begin();
}
+ static inline ChildIteratorType child_end(NodeType* N) {
+ return N->end();
+ }
+};
- void calculate(const DominatorTree &DT);
- ETNode *getNodeForBlock(BasicBlock *BB);
+template <> struct GraphTraits<DominatorTree*>
+ : public GraphTraits<DomTreeNode *> {
+ static NodeType *getEntryNode(DominatorTree *DT) {
+ return DT->getRootNode();
+ }
};
+
//===----------------------------------------------------------------------===//
/// DominanceFrontierBase - Common base class for computing forward and inverse
/// dominance frontiers for a function.
///
-class DominanceFrontierBase : public DominatorBase {
+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(intptr_t ID, bool isPostDom)
- : DominatorBase(ID, isPostDom) {}
+ DominanceFrontierBase(void *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(); }
Frontiers.insert(std::make_pair(BB, frontier));
}
+ /// 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) {
assert(I != end() && "BB is not in DominanceFrontier!");
I->second.insert(Node);
I->second.erase(Node);
}
+ /// 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(std::ostream &OS, const Module* = 0) const;
void print(std::ostream *OS, const Module* M = 0) const {
if (OS) print(*OS, M);
}
+ virtual void dump();
};
///
class DominanceFrontier : public DominanceFrontierBase {
public:
- static const char ID; // Pass ID, replacement for typeid
+ static char ID; // Pass ID, replacement for typeid
DominanceFrontier() :
- DominanceFrontierBase((intptr_t)& ID, false) {}
+ DominanceFrontierBase(&ID, false) {}
BasicBlock *getRoot() const {
assert(Roots.size() == 1 && "Should always have entry node!");
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);
};