-//===- llvm/Analysis/DominatorSet.h - Dominator Set Calculation --*- C++ -*--=//
+//===- llvm/Analysis/Dominators.h - Dominator Info Calculation --*- C++ -*-===//
//
// This file defines the following classes:
-// 1. DominatorSet: Calculates the [reverse] dominator set for a method
+// 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
-// method.
+// function.
//
// These data structures are listed in increasing order of complexity. It
// takes longer to calculate the dominator frontier, for example, than the
//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_DOMINATORS_H
-#define LLVM_DOMINATORS_H
+#ifndef LLVM_ANALYSIS_DOMINATORS_H
+#define LLVM_ANALYSIS_DOMINATORS_H
+#include "llvm/Pass.h"
#include <set>
-#include <map>
-#include <vector>
-class Method;
-class BasicBlock;
-namespace cfg {
+class Instruction;
+
+template <typename GraphType> struct GraphTraits;
//===----------------------------------------------------------------------===//
//
// DominatorBase - Base class that other, more interesting dominator analyses
// inherit from.
//
-class DominatorBase {
+class DominatorBase : public FunctionPass {
protected:
- const BasicBlock *Root;
- inline DominatorBase(const BasicBlock *root = 0) : Root(root) {}
+ std::vector<BasicBlock*> Roots;
+ const bool IsPostDominators;
+
+ inline DominatorBase(bool isPostDom) : Roots(), IsPostDominators(isPostDom) {}
public:
- inline const BasicBlock *getRoot() const { return Root; }
- bool isPostDominator() const; // Returns true if analysis based of postdoms
+ // 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; }
+
+ // Returns true if analysis based of postdoms
+ bool isPostDominator() const { return IsPostDominators; }
};
//===----------------------------------------------------------------------===//
//
-// DominatorSet - Maintain a set<const BasicBlock*> for every basic block in a
-// method, that represents the blocks that dominate the block.
+// DominatorSet - Maintain a set<BasicBlock*> for every basic block in a
+// function, that represents the blocks that dominate the block. If the block
+// is unreachable in this function, the set will be empty. This cannot happen
+// for reachable code, because every block dominates at least itself.
//
-class DominatorSet : public DominatorBase {
+class DominatorSetBase : public DominatorBase {
public:
- typedef std::set<const BasicBlock*> DomSetType; // Dom set for a bb
+ typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
// Map of dom sets
- typedef std::map<const BasicBlock*, DomSetType> DomSetMapType;
-private:
+ typedef std::map<BasicBlock*, DomSetType> DomSetMapType;
+protected:
DomSetMapType Doms;
-
- void calcForwardDominatorSet(const Method *M);
public:
- // DominatorSet ctor - Build either the dominator set or the post-dominator
- // set for a method... Building the postdominator set may require the analysis
- // routine to modify the method so that there is only a single return in the
- // method.
- //
- DominatorSet(const Method *M);
- DominatorSet( Method *M, bool PostDomSet);
+ 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 const_iterator find(const BasicBlock* B) const { return Doms.find(B); }
+ 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); }
- // getDominators - Return the set of basic blocks that dominate the specified
- // block.
- //
- inline const DomSetType &getDominators(const BasicBlock *BB) const {
+
+ /// 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 method!");
+ assert(I != end() && "BB not in function!");
return I->second;
}
- // dominates - Return true if A dominates B.
- //
- inline bool dominates(const BasicBlock *A, const BasicBlock *B) const {
+ /// isReachable - Return true if the specified basicblock is reachable. If
+ /// the block is reachable, we have dominator set information for it.
+ bool isReachable(BasicBlock *BB) const {
+ return !getDominators(BB).empty();
+ }
+
+ /// dominates - Return true if A dominates B.
+ ///
+ inline bool dominates(BasicBlock *A, BasicBlock *B) const {
return getDominators(B).count(A) != 0;
}
+
+ /// properlyDominates - Return true if A dominates B and A != B.
+ ///
+ bool properlyDominates(BasicBlock *A, BasicBlock *B) const {
+ return dominates(A, B) && A != B;
+ }
+
+ /// print - Convert to human readable form
+ virtual void print(std::ostream &OS) const;
+
+ /// 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) const;
+
+ //===--------------------------------------------------------------------===//
+ // API to update (Post)DominatorSet information based on modifications to
+ // the CFG...
+
+ /// 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));
+ }
+
+ // 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);
+ }
+};
+
+
+//===-------------------------------------
+// DominatorSet Class - Concrete subclass of DominatorSetBase that is used to
+// compute a normal dominator set.
+//
+struct DominatorSet : public DominatorSetBase {
+ DominatorSet() : DominatorSetBase(false) {}
+
+ virtual bool runOnFunction(Function &F);
+
+ /// 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();
+
+ BasicBlock *getRoot() const {
+ assert(Roots.size() == 1 && "Should always have entry node!");
+ return Roots[0];
+ }
+
+ // getAnalysisUsage - This simply provides a dominator set
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ }
+private:
+ void calculateDominatorsFromBlock(BasicBlock *BB);
};
//===----------------------------------------------------------------------===//
//
// ImmediateDominators - Calculate the immediate dominator for each node in a
-// method.
+// function.
//
-class ImmediateDominators : public DominatorBase {
- std::map<const BasicBlock*, const BasicBlock*> IDoms;
- void calcIDoms(const DominatorSet &DS);
+class ImmediateDominatorsBase : public DominatorBase {
+protected:
+ std::map<BasicBlock*, BasicBlock*> IDoms;
+ void calcIDoms(const DominatorSetBase &DS);
public:
+ ImmediateDominatorsBase(bool isPostDom) : DominatorBase(isPostDom) {}
- // ImmediateDominators ctor - Calculate the idom mapping, for a method, or
- // from a dominator set calculated for something else...
- //
- inline ImmediateDominators(const DominatorSet &DS)
- : DominatorBase(DS.getRoot()) {
- calcIDoms(DS); // Can be used to make rev-idoms
- }
+ virtual void releaseMemory() { IDoms.clear(); }
// Accessor interface:
- typedef std::map<const BasicBlock*, const BasicBlock*> IDomMapType;
+ 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(const BasicBlock* B) const { return IDoms.find(B);}
+ 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 const BasicBlock *operator[](const BasicBlock *BB) const {
- std::map<const BasicBlock*, const BasicBlock*>::const_iterator I =
- IDoms.find(BB);
+ 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;
}
+
+ //===--------------------------------------------------------------------===//
+ // API to update Immediate(Post)Dominators 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) {
+ assert(get(BB) == 0 && "BasicBlock already in idom info!");
+ IDoms[BB] = 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 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;
+ }
+
+ // print - Convert to human readable form
+ virtual void print(std::ostream &OS) const;
+};
+
+//===-------------------------------------
+// ImmediateDominators Class - Concrete subclass of ImmediateDominatorsBase that
+// is used to compute a normal immediate dominator set.
+//
+struct ImmediateDominators : public ImmediateDominatorsBase {
+ ImmediateDominators() : ImmediateDominatorsBase(false) {}
+
+ BasicBlock *getRoot() const {
+ assert(Roots.size() == 1 && "Should always have entry node!");
+ return Roots[0];
+ }
+
+ virtual bool runOnFunction(Function &F) {
+ IDoms.clear(); // Reset from the last time we were run...
+ DominatorSet &DS = getAnalysis<DominatorSet>();
+ Roots = DS.getRoots();
+ calcIDoms(DS);
+ return false;
+ }
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ AU.addRequired<DominatorSet>();
+ }
};
//===----------------------------------------------------------------------===//
//
-// DominatorTree - Calculate the immediate dominator tree for a method.
+// DominatorTree - Calculate the immediate dominator tree for a function.
//
-class DominatorTree : public DominatorBase {
+class DominatorTreeBase : public DominatorBase {
+protected:
class Node2;
public:
typedef Node2 Node;
-private:
- std::map<const BasicBlock*, Node*> Nodes;
- void calculate(const DominatorSet &DS);
- typedef std::map<const BasicBlock*, Node*> NodeMapType;
+protected:
+ std::map<BasicBlock*, Node*> Nodes;
+ void reset();
+ typedef std::map<BasicBlock*, Node*> NodeMapType;
+
+ Node *RootNode;
public:
- class Node2 : public std::vector<Node*> {
+ class Node2 {
friend class DominatorTree;
- const BasicBlock *TheNode;
- Node2 * const IDom;
+ friend class PostDominatorTree;
+ friend class DominatorTreeBase;
+ BasicBlock *TheNode;
+ Node2 *IDom;
+ std::vector<Node*> Children;
public:
- inline const BasicBlock *getNode() const { return TheNode; }
+ 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 *this; }
+ 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!
}
private:
- inline Node2(const BasicBlock *node, Node *iDom)
+ inline Node2(BasicBlock *node, Node *iDom)
: TheNode(node), IDom(iDom) {}
- inline Node2 *addChild(Node *C) { push_back(C); return C; }
+ inline Node2 *addChild(Node *C) { Children.push_back(C); return C; }
+
+ void setIDom(Node2 *NewIDom);
};
public:
- // DominatorTree ctors - Compute a dominator tree, given various amounts of
- // previous knowledge...
- inline DominatorTree(const DominatorSet &DS) : DominatorBase(DS.getRoot()) {
- calculate(DS);
- }
+ DominatorTreeBase(bool isPostDom) : DominatorBase(isPostDom) {}
+ ~DominatorTreeBase() { reset(); }
- DominatorTree(const ImmediateDominators &IDoms);
- ~DominatorTree();
+ virtual void releaseMemory() { reset(); }
- inline const Node *operator[](const BasicBlock *BB) const {
+ /// 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);
+ }
+
+ // 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.
+ //
+ Node *getRootNode() { return RootNode; }
+ const Node *getRootNode() const { return RootNode; }
+
+ //===--------------------------------------------------------------------===//
+ // 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) {
+ assert(getNode(BB) == 0 && "Block already in dominator tree!");
+ assert(IDomNode && "Not immediate dominator specified for block!");
+ return Nodes[BB] = IDomNode->addChild(new Node(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);
+ }
+
+ /// print - Convert to human readable form
+ virtual void print(std::ostream &OS) const;
};
+//===-------------------------------------
+// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
+// compute a normal dominator tree.
+//
+struct DominatorTree : public DominatorTreeBase {
+ DominatorTree() : DominatorTreeBase(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...
+ DominatorSet &DS = getAnalysis<DominatorSet>();
+ Roots = DS.getRoots();
+ calculate(DS);
+ return false;
+ }
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ AU.addRequired<DominatorSet>();
+ }
+private:
+ void calculate(const DominatorSet &DS);
+};
+
+//===-------------------------------------
+// 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;
+
+ static NodeType *getEntryNode(NodeType *N) {
+ return N;
+ }
+ static inline ChildIteratorType child_begin(NodeType* N) {
+ return N->begin();
+ }
+ static inline ChildIteratorType child_end(NodeType* N) {
+ return N->end();
+ }
+};
+
+template <> struct GraphTraits<DominatorTree*>
+ : public GraphTraits<DominatorTree::Node*> {
+ static NodeType *getEntryNode(DominatorTree *DT) {
+ return DT->getRootNode();
+ }
+};
+
//===----------------------------------------------------------------------===//
//
-// DominanceFrontier - Calculate the dominance frontiers for a method.
+// DominanceFrontier - Calculate the dominance frontiers for a function.
//
-class DominanceFrontier : public DominatorBase {
+class DominanceFrontierBase : public DominatorBase {
public:
- typedef std::set<const BasicBlock*> DomSetType; // Dom set for a bb
- typedef std::map<const BasicBlock*, DomSetType> DomSetMapType; // Dom set map
-private:
+ typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
+ typedef std::map<BasicBlock*, DomSetType> DomSetMapType; // Dom set map
+protected:
DomSetMapType Frontiers;
- const DomSetType &calcDomFrontier(const DominatorTree &DT,
- const DominatorTree::Node *Node);
- const DomSetType &calcPostDomFrontier(const DominatorTree &DT,
- const DominatorTree::Node *Node);
public:
- DominanceFrontier(const DominatorSet &DS) : DominatorBase(DS.getRoot()) {
- const DominatorTree DT(DS);
- if (isPostDominator())
- calcPostDomFrontier(DT, DT[Root]);
- else
- calcDomFrontier(DT, DT[Root]);
- }
- DominanceFrontier(const ImmediateDominators &ID)
- : DominatorBase(ID.getRoot()) {
- const DominatorTree DT(ID);
- if (isPostDominator())
- calcPostDomFrontier(DT, DT[Root]);
- else
- calcDomFrontier(DT, DT[Root]);
- }
- DominanceFrontier(const DominatorTree &DT) : DominatorBase(DT.getRoot()) {
- if (isPostDominator())
- calcPostDomFrontier(DT, DT[Root]);
- else
- calcDomFrontier(DT, DT[Root]);
- }
+ DominanceFrontierBase(bool isPostDom) : DominatorBase(isPostDom) {}
+
+ virtual void releaseMemory() { Frontiers.clear(); }
// Accessor interface:
+ typedef DomSetMapType::iterator iterator;
typedef DomSetMapType::const_iterator const_iterator;
- inline const_iterator begin() const { return Frontiers.begin(); }
- inline const_iterator end() const { return Frontiers.end(); }
- inline const_iterator find(const BasicBlock* B) const { return Frontiers.find(B);}
+ iterator begin() { return Frontiers.begin(); }
+ const_iterator begin() const { return Frontiers.begin(); }
+ iterator end() { return Frontiers.end(); }
+ const_iterator end() const { return Frontiers.end(); }
+ 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) {
+ assert(find(BB) == end() && "Block already in DominanceFrontier!");
+ Frontiers.insert(std::make_pair(BB, frontier));
+ }
+
+ void addToFrontier(iterator I, BasicBlock *Node) {
+ assert(I != end() && "BB is not in DominanceFrontier!");
+ I->second.insert(Node);
+ }
+
+ void removeFromFrontier(iterator I, BasicBlock *Node) {
+ assert(I != end() && "BB is not in DominanceFrontier!");
+ assert(I->second.count(Node) && "Node is not in DominanceFrontier of BB");
+ I->second.erase(Node);
+ }
+
+ // print - Convert to human readable form
+ virtual void print(std::ostream &OS) const;
};
-} // End namespace cfg
+
+//===-------------------------------------
+// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
+// compute a normal dominator tree.
+//
+struct DominanceFrontier : public DominanceFrontierBase {
+ DominanceFrontier() : DominanceFrontierBase(false) {}
+
+ 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>();
+ Roots = DT.getRoots();
+ assert(Roots.size() == 1 && "Only one entry block for forward domfronts!");
+ calculate(DT, DT[Roots[0]]);
+ return false;
+ }
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ AU.addRequired<DominatorTree>();
+ }
+private:
+ const DomSetType &calculate(const DominatorTree &DT,
+ const DominatorTree::Node *Node);
+};
#endif
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