llvm-6502/include/llvm/Analysis/Dominators.h
2002-10-31 02:39:48 +00:00

434 lines
14 KiB
C++

//===- llvm/Analysis/Dominators.h - Dominator Info Calculation ---*- C++ -*--=//
//
// 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
// 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.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_DOMINATORS_H
#define LLVM_ANALYSIS_DOMINATORS_H
#include "llvm/Pass.h"
#include <set>
class Instruction;
template <typename GraphType> struct GraphTraits;
//===----------------------------------------------------------------------===//
//
// DominatorBase - Base class that other, more interesting dominator analyses
// inherit from.
//
class DominatorBase : public FunctionPass {
protected:
BasicBlock *Root;
const bool IsPostDominators;
inline DominatorBase(bool isPostDom) : Root(0), IsPostDominators(isPostDom) {}
public:
inline BasicBlock *getRoot() const { return Root; }
// 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;
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); }
/// 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;
}
/// 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 neccesary 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();
// 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
// function.
//
class ImmediateDominatorsBase : public DominatorBase {
protected:
std::map<BasicBlock*, BasicBlock*> IDoms;
void calcIDoms(const DominatorSetBase &DS);
public:
ImmediateDominatorsBase(bool isPostDom) : DominatorBase(isPostDom) {}
virtual void releaseMemory() { IDoms.clear(); }
// 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;
}
//===--------------------------------------------------------------------===//
// 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) {}
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;
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<DominatorSet>();
}
};
//===----------------------------------------------------------------------===//
//
// 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;
}
private:
inline Node2(BasicBlock *node, Node *iDom)
: TheNode(node), IDom(iDom) {}
inline Node2 *addChild(Node *C) { Children.push_back(C); return C; }
void setIDom(Node2 *NewIDom);
};
public:
DominatorTreeBase(bool isPostDom) : DominatorBase(isPostDom) {}
~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 Node *operator[](BasicBlock *BB) const {
return getNode(BB);
}
//===--------------------------------------------------------------------===// // 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) {}
virtual bool runOnFunction(Function &F) {
reset(); // Reset from the last time we were run...
DominatorSet &DS = getAnalysis<DominatorSet>();
Root = DS.getRoot();
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*> {
typedef DominatorTree::Node NodeType;
typedef NodeType::iterator ChildIteratorType;
static NodeType *getEntryNode(DominatorTree *DT) {
return DT->getNode(DT->getRoot());
}
static inline ChildIteratorType child_begin(NodeType* N) {
return N->begin();
}
static inline ChildIteratorType child_end(NodeType* N) {
return N->end();
}
};
//===----------------------------------------------------------------------===//
//
// DominanceFrontier - Calculate the dominance frontiers for a function.
//
class DominanceFrontierBase : public DominatorBase {
public:
typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
typedef std::map<BasicBlock*, DomSetType> DomSetMapType; // Dom set map
protected:
DomSetMapType Frontiers;
public:
DominanceFrontierBase(bool isPostDom) : DominatorBase(isPostDom) {}
virtual void releaseMemory() { Frontiers.clear(); }
// Accessor interface:
typedef DomSetMapType::const_iterator const_iterator;
const_iterator begin() const { return Frontiers.begin(); }
const_iterator end() const { return Frontiers.end(); }
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(BasicBlock *BB, BasicBlock *Node) {
DomSetMapType::iterator I = Frontiers.find(BB);
assert(I != end() && "BB is not in DominanceFrontier!");
I->second.insert(Node);
}
void removeFromFrontier(BasicBlock *BB, BasicBlock *Node) {
DomSetMapType::iterator I = Frontiers.find(BB);
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;
};
//===-------------------------------------
// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
// compute a normal dominator tree.
//
struct DominanceFrontier : public DominanceFrontierBase {
DominanceFrontier() : DominanceFrontierBase(false) {}
virtual bool runOnFunction(Function &) {
Frontiers.clear();
DominatorTree &DT = getAnalysis<DominatorTree>();
Root = DT.getRoot();
calculate(DT, DT[Root]);
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