llvm-6502/include/llvm/Analysis/Dominators.h
Chris Lattner 7e70829632 MEGAPATCH checkin.
For details, See: docs/2002-06-25-MegaPatchInfo.txt


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2779 91177308-0d34-0410-b5e6-96231b3b80d8
2002-06-25 16:13:24 +00:00

330 lines
11 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_DOMINATORS_H
#define LLVM_DOMINATORS_H
#include "llvm/Pass.h"
#include <set>
class Instruction;
//===----------------------------------------------------------------------===//
//
// 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 DominatorSet : public DominatorBase {
public:
typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
// Map of dom sets
typedef std::map<BasicBlock*, DomSetType> DomSetMapType;
private:
DomSetMapType Doms;
void calcForwardDominatorSet(Function &F);
void calcPostDominatorSet(Function &F);
public:
// DominatorSet ctor - Build either the dominator set or the post-dominator
// set for a function...
//
static AnalysisID ID; // Build dominator set
static AnalysisID PostDomID; // Build postdominator set
DominatorSet(AnalysisID id) : DominatorBase(id == PostDomID) {}
virtual const char *getPassName() const {
if (isPostDominator()) return "Post-Dominator Set Construction";
else return "Dominator Set Construction";
}
virtual bool runOnFunction(Function &F);
// 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;
}
// 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;
// getAnalysisUsage - This obviously provides a dominator set, but it also
// uses the UnifyFunctionExitNode pass if building post-dominators
//
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
};
//===----------------------------------------------------------------------===//
//
// ImmediateDominators - Calculate the immediate dominator for each node in a
// function.
//
class ImmediateDominators : public DominatorBase {
std::map<BasicBlock*, BasicBlock*> IDoms;
void calcIDoms(const DominatorSet &DS);
public:
// ImmediateDominators ctor - Calculate the idom or post-idom mapping,
// for a function...
//
static AnalysisID ID; // Build immediate dominators
static AnalysisID PostDomID; // Build immediate postdominators
ImmediateDominators(AnalysisID id) : DominatorBase(id == PostDomID) {}
virtual const char *getPassName() const {
if (isPostDominator()) return "Immediate Post-Dominators Construction";
else return "Immediate Dominators Construction";
}
virtual bool runOnFunction(Function &F) {
IDoms.clear(); // Reset from the last time we were run...
DominatorSet *DS;
if (isPostDominator())
DS = &getAnalysis<DominatorSet>(DominatorSet::PostDomID);
else
DS = &getAnalysis<DominatorSet>();
Root = DS->getRoot();
calcIDoms(*DS); // Can be used to make rev-idoms
return false;
}
// Accessor interface:
typedef std::map<BasicBlock*, BasicBlock*> IDomMapType;
typedef IDomMapType::const_iterator const_iterator;
inline const_iterator begin() const { return IDoms.begin(); }
inline const_iterator end() const { return IDoms.end(); }
inline const_iterator find(BasicBlock* B) const { return IDoms.find(B);}
// operator[] - Return the idom for the specified basic block. The start
// node returns null, because it does not have an immediate dominator.
//
inline BasicBlock *operator[](BasicBlock *BB) const {
std::map<BasicBlock*, BasicBlock*>::const_iterator I = IDoms.find(BB);
return I != IDoms.end() ? I->second : 0;
}
// getAnalysisUsage - This obviously provides a dominator tree, but it
// can only do so with the input of dominator sets
//
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
if (isPostDominator()) {
AU.addRequired(DominatorSet::PostDomID);
AU.addProvided(PostDomID);
} else {
AU.addRequired(DominatorSet::ID);
AU.addProvided(ID);
}
}
};
//===----------------------------------------------------------------------===//
//
// DominatorTree - Calculate the immediate dominator tree for a function.
//
class DominatorTree : public DominatorBase {
class Node2;
public:
typedef Node2 Node;
private:
std::map<BasicBlock*, Node*> Nodes;
void calculate(const DominatorSet &DS);
void reset();
typedef std::map<BasicBlock*, Node*> NodeMapType;
public:
class Node2 : public std::vector<Node*> {
friend class DominatorTree;
BasicBlock *TheNode;
Node2 *IDom;
public:
inline BasicBlock *getNode() const { return TheNode; }
inline Node2 *getIDom() const { return IDom; }
inline const std::vector<Node*> &getChildren() const { return *this; }
// 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) { push_back(C); return C; }
};
public:
// DominatorTree ctor - Compute a dominator tree, given various amounts of
// previous knowledge...
static AnalysisID ID; // Build dominator tree
static AnalysisID PostDomID; // Build postdominator tree
DominatorTree(AnalysisID id) : DominatorBase(id == PostDomID) {}
~DominatorTree() { reset(); }
virtual const char *getPassName() const {
if (isPostDominator()) return "Post-Dominator Tree Construction";
else return "Dominator Tree Construction";
}
virtual bool runOnFunction(Function &F) {
reset();
DominatorSet *DS;
if (isPostDominator())
DS = &getAnalysis<DominatorSet>(DominatorSet::PostDomID);
else
DS = &getAnalysis<DominatorSet>();
Root = DS->getRoot();
calculate(*DS); // Can be used to make rev-idoms
return false;
}
inline Node *operator[](BasicBlock *BB) const {
NodeMapType::const_iterator i = Nodes.find(BB);
return (i != Nodes.end()) ? i->second : 0;
}
// getAnalysisUsage - This obviously provides a dominator tree, but it
// uses dominator sets
//
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
if (isPostDominator()) {
AU.addRequired(DominatorSet::PostDomID);
AU.addProvided(PostDomID);
} else {
AU.addRequired(DominatorSet::ID);
AU.addProvided(ID);
}
}
};
//===----------------------------------------------------------------------===//
//
// DominanceFrontier - Calculate the dominance frontiers for a function.
//
class DominanceFrontier : public DominatorBase {
public:
typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
typedef std::map<BasicBlock*, DomSetType> DomSetMapType; // Dom set map
private:
DomSetMapType Frontiers;
const DomSetType &calcDomFrontier(const DominatorTree &DT,
const DominatorTree::Node *Node);
const DomSetType &calcPostDomFrontier(const DominatorTree &DT,
const DominatorTree::Node *Node);
public:
// DominatorFrontier ctor - Compute dominator frontiers for a function
//
static AnalysisID ID; // Build dominator frontier
static AnalysisID PostDomID; // Build postdominator frontier
DominanceFrontier(AnalysisID id) : DominatorBase(id == PostDomID) {}
virtual const char *getPassName() const {
if (isPostDominator()) return "Post-Dominance Frontier Construction";
else return "Dominance Frontier Construction";
}
virtual bool runOnFunction(Function &) {
Frontiers.clear();
DominatorTree *DT;
if (isPostDominator())
DT = &getAnalysis<DominatorTree>(DominatorTree::PostDomID);
else
DT = &getAnalysis<DominatorTree>();
Root = DT->getRoot();
if (isPostDominator())
calcPostDomFrontier(*DT, (*DT)[Root]);
else
calcDomFrontier(*DT, (*DT)[Root]);
return false;
}
// Accessor interface:
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(BasicBlock* B) const { return Frontiers.find(B); }
// getAnalysisUsage - This obviously provides the dominance frontier, but it
// uses dominator sets
//
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
if (isPostDominator()) {
AU.addRequired(DominatorTree::PostDomID);
AU.addProvided(PostDomID);
} else {
AU.addRequired(DominatorTree::ID);
AU.addProvided(ID);
}
}
};
#endif