//
// This file defines the following classes:
// 1. DominatorTree: Represent dominators 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
+// 2. DominanceFrontier: Calculate and hold the dominance frontier for a
// function.
//
// These data structures are listed in increasing order of complexity. It
#ifndef LLVM_ANALYSIS_DOMINATORS_H
#define LLVM_ANALYSIS_DOMINATORS_H
-#include "llvm/Analysis/ET-Forest.h"
#include "llvm/Pass.h"
#include <set>
bool isPostDominator() const { return IsPostDominators; }
};
+
+//===----------------------------------------------------------------------===//
+// DomTreeNode - Dominator Tree Node
+class DominatorTreeBase;
+class PostDominatorTree;
+class DomTreeNode {
+ BasicBlock *TheBB;
+ DomTreeNode *IDom;
+ std::vector<DomTreeNode*> Children;
+ int DFSNumIn, DFSNumOut;
+
+ friend class DominatorTreeBase;
+ friend class PostDominatorTree;
+public:
+ typedef std::vector<DomTreeNode*>::iterator iterator;
+ typedef std::vector<DomTreeNode*>::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 DomTreeNode *getIDom() const { return IDom; }
+ inline const std::vector<DomTreeNode*> &getChildren() const { return Children; }
+
+ inline DomTreeNode(BasicBlock *BB, DomTreeNode *iDom)
+ : TheBB(BB), IDom(iDom), DFSNumIn(-1), DFSNumOut(-1) { }
+ inline DomTreeNode *addChild(DomTreeNode *C) { Children.push_back(C); return C; }
+ void setIDom(DomTreeNode *NewIDom);
+
+private:
+ // Return true if this node is dominated by other. Use this only if DFS info is valid.
+ bool DominatedBy(const DomTreeNode *other) const {
+ return this->DFSNumIn >= other->DFSNumIn &&
+ this->DFSNumOut <= other->DFSNumOut;
+ }
+
+ /// assignDFSNumber - Assign In and Out numbers while walking dominator tree
+ /// in dfs order.
+ void assignDFSNumber(int num);
+};
+
//===----------------------------------------------------------------------===//
/// 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;
+ typedef std::map<BasicBlock*, DomTreeNode*> DomTreeNodeMapType;
+ DomTreeNodeMapType DomTreeNodes;
+ DomTreeNode *RootNode;
+ bool DFSInfoValid;
+ unsigned int SlowQueries;
+ // Information record used during immediate dominators computation.
struct InfoRec {
unsigned Semi;
unsigned Size;
// Info - Collection of information used during the computation of idoms.
std::map<BasicBlock*, InfoRec> Info;
-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;
- }
-
- /// 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);
- }
-
- 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);
- };
+ void updateDFSNumbers();
-public:
+ public:
DominatorTreeBase(intptr_t ID, bool isPostDom)
- : DominatorBase(ID, isPostDom) {}
+ : DominatorBase(ID, isPostDom), DFSInfoValid(false), SlowQueries(0) {}
~DominatorTreeBase() { reset(); }
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 DomTreeNode *getNode(BasicBlock *BB) const {
+ DomTreeNodeMapType::const_iterator i = DomTreeNodes.find(BB);
+ return (i != DomTreeNodes.end()) ? i->second : 0;
}
- inline Node *operator[](BasicBlock *BB) const {
+ inline DomTreeNode *operator[](BasicBlock *BB) const {
return getNode(BB);
}
+ /// getIDomBlock - return basic block BB's immediate dominator basic block.
+ ///
+ BasicBlock *getIDomBlock(BasicBlock *BB) {
+ DomTreeNode *N = getNode(BB);
+ assert (N && "Missing dominator tree node");
+ DomTreeNode *I = N->getIDom();
+ assert (N && "Missing immediate dominator");
+ return I->getBlock();
+ }
+
/// 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
/// post-dominance information must be capable of dealing with this
/// possibility.
///
- Node *getRootNode() { return RootNode; }
- const Node *getRootNode() const { return RootNode; }
+ DomTreeNode *getRootNode() { return RootNode; }
+ const DomTreeNode *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 DomTreeNode *A, DomTreeNode *B) const {
+ if (A == 0 || B == 0) return false;
+ return dominatedBySlowTreeWalk(A, B);
+ }
+
+ inline bool properlyDominates(BasicBlock *A, BasicBlock *B) {
+ return properlyDominates(getNode(A), getNode(B));
+ }
+
+ bool dominatedBySlowTreeWalk(const DomTreeNode *A,
+ const DomTreeNode *B) const {
+ const DomTreeNode *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.
+ const bool isReachableFromEntry(BasicBlock* A);
+
+ /// dominates - Returns true iff A dominates B. Note that this is not a
+ /// constant time operation!
+ ///
+ inline bool dominates(const DomTreeNode *A, DomTreeNode *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(BasicBlock *A, BasicBlock *B) {
+ if (A == B)
+ return true;
+
+ return dominates(getNode(A), getNode(B));
+ }
+
+ /// findNearestCommonDominator - Find nearest common dominator basic block
+ /// for basic block A and B. If there is no such block then return NULL.
+ BasicBlock *findNearestCommonDominator(BasicBlock *A, BasicBlock *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);
//===--------------------------------------------------------------------===//
// 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.
+ DomTreeNode *addNewBlock(BasicBlock *BB, BasicBlock *DomBB) {
assert(getNode(BB) == 0 && "Block already in dominator tree!");
+ DomTreeNode *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 DomTreeNode(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(DomTreeNode *N, DomTreeNode *NewIDom) {
assert(N && NewIDom && "Cannot change null node pointers!");
+ DFSInfoValid = false;
N->setIDom(NewIDom);
}
+ void changeImmediateDominator(BasicBlock *BB, BasicBlock *NewBB) {
+ changeImmediateDominator(getNode(BB), getNode(NewBB));
+ }
+
/// 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) {
assert(getNode(BB) && "Removing node that isn't in dominator tree.");
- Nodes.erase(BB);
+ DomTreeNodes.erase(BB);
}
/// print - Convert to human readable form
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
+
+ /// splitBlock
+ /// BB is split and now it has one successor. Update dominator tree to
+ /// reflect this change.
+ void splitBlock(BasicBlock *BB);
private:
void calculate(Function& F);
- Node *getNodeForBlock(BasicBlock *BB);
+ DomTreeNode *getNodeForBlock(BasicBlock *BB);
unsigned DFSPass(BasicBlock *V, InfoRec &VInfo, unsigned N);
void Compress(BasicBlock *V);
BasicBlock *Eval(BasicBlock *v);
/// DominatorTree GraphTraits specialization so the DominatorTree can be
/// iterable by generic graph iterators.
///
-template <> struct GraphTraits<DominatorTree::Node*> {
- typedef DominatorTree::Node NodeType;
+template <> struct GraphTraits<DomTreeNode*> {
+ typedef DomTreeNode NodeType;
typedef NodeType::iterator ChildIteratorType;
static NodeType *getEntryNode(NodeType *N) {
};
template <> struct GraphTraits<DominatorTree*>
- : public GraphTraits<DominatorTree::Node*> {
+ : public GraphTraits<DomTreeNode*> {
static NodeType *getEntryNode(DominatorTree *DT) {
return DT->getRootNode();
}
};
-//===-------------------------------------
-/// ET-Forest Class - Class used to construct forwards and backwards
-/// ET-Forests
-///
-class ETForestBase : public DominatorBase {
-public:
- ETForestBase(intptr_t ID, bool isPostDom)
- : DominatorBase(ID, isPostDom), Nodes(),
- DFSInfoValid(false), SlowQueries(0) {}
-
- virtual void releaseMemory() { reset(); }
-
- typedef std::map<BasicBlock*, ETNode*> ETMapType;
-
- void updateDFSNumbers();
-
- /// dominates - Return true if A dominates B.
- ///
- inline bool dominates(BasicBlock *A, BasicBlock *B) {
- if (A == B)
- 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);
- }
- }
-
- // 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;
- }
-
- /// 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>();
- }
-
- /// 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;
- }
-
- 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();
- }
- }
-
- 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);
- }
- virtual void dump();
-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 ETNode *operator[](BasicBlock *BB) const {
- return getNode(BB);
- }
-
- 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 char ID; // Pass identification, replacement for typeid
-
- ETForest() : ETForestBase((intptr_t)&ID, false) {}
-
- BasicBlock *getRoot() const {
- assert(Roots.size() == 1 && "Should always have entry node!");
- return Roots[0];
- }
-
- 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;
- }
-
- void calculate(const DominatorTree &DT);
- ETNode *getNodeForBlock(BasicBlock *BB);
-};
-
//===----------------------------------------------------------------------===//
/// DominanceFrontierBase - Common base class for computing forward and inverse
/// dominance frontiers for a function.
AU.setPreservesAll();
AU.addRequired<DominatorTree>();
}
+
+ /// splitBlock
+ /// BB is split and now it has one successor. Update dominace frontier to
+ /// reflect this change.
+ void splitBlock(BasicBlock *BB);
+
private:
const DomSetType &calculate(const DominatorTree &DT,
- const DominatorTree::Node *Node);
+ const DomTreeNode *Node);
};
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