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//===- llvm/Analysis/DominanceFrontier.h - Dominator Frontiers --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the DominanceFrontier class, which calculate and holds the
// dominance frontier for a function.
//
// This should be considered deprecated, don't add any more uses of this data
// structure.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_DOMINANCEFRONTIER_H
#define LLVM_ANALYSIS_DOMINANCEFRONTIER_H
#include "llvm/IR/Dominators.h"
#include <map>
#include <set>
namespace llvm {
//===----------------------------------------------------------------------===//
/// DominanceFrontierBase - Common base class for computing forward and inverse
/// dominance frontiers for a function.
///
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(char &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; }
void releaseMemory() override { Frontiers.clear(); }
// Accessor interface:
typedef DomSetMapType::iterator iterator;
typedef DomSetMapType::const_iterator const_iterator;
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); }
iterator addBasicBlock(BasicBlock *BB, const DomSetType &frontier) {
assert(find(BB) == end() && "Block already in DominanceFrontier!");
return Frontiers.insert(std::make_pair(BB, frontier)).first;
}
/// 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);
}
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);
}
/// 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
///
void print(raw_ostream &OS, const Module* = 0) const override;
/// dump - Dump the dominance frontier to dbgs().
void dump() const;
};
//===-------------------------------------
/// DominanceFrontier Class - Concrete subclass of DominanceFrontierBase that is
/// used to compute a forward dominator frontiers.
///
class DominanceFrontier : public DominanceFrontierBase {
virtual void anchor();
public:
static char ID; // Pass ID, replacement for typeid
DominanceFrontier() :
DominanceFrontierBase(ID, false) {
initializeDominanceFrontierPass(*PassRegistry::getPassRegistry());
}
BasicBlock *getRoot() const {
assert(Roots.size() == 1 && "Should always have entry node!");
return Roots[0];
}
bool runOnFunction(Function &) override {
Frontiers.clear();
DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
Roots = DT.getRoots();
assert(Roots.size() == 1 && "Only one entry block for forward domfronts!");
calculate(DT, DT[Roots[0]]);
return false;
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
AU.addRequired<DominatorTreeWrapperPass>();
}
const DomSetType &calculate(const DominatorTree &DT,
const DomTreeNode *Node);
};
} // End llvm namespace
#endif
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