DominanceFrontier.h

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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.
///
template <class BlockT>
class DominanceFrontierBase {
public:
  typedef std::set<BlockT *> DomSetType;                // Dom set for a bb
  typedef std::map<BlockT *, DomSetType> DomSetMapType; // Dom set map

protected:
  typedef GraphTraits<BlockT *> BlockTraits;

  DomSetMapType Frontiers;
  std::vector<BlockT *> Roots;
  const bool IsPostDominators;

public:
  DominanceFrontierBase(bool isPostDom) : 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<BlockT *> &getRoots() const {
    return Roots;
  }

  BlockT *getRoot() const {
    assert(Roots.size() == 1 && "Should always have entry node!");
    return Roots[0];
  }

  /// isPostDominator - Returns true if analysis based of postdoms
  ///
  bool isPostDominator() const {
    return IsPostDominators;
  }

  void releaseMemory() {
    Frontiers.clear();
  }

  // Accessor interface:
  typedef typename DomSetMapType::iterator iterator;
  typedef typename 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(BlockT *B) { return Frontiers.find(B); }
  const_iterator find(BlockT *B) const { return Frontiers.find(B); }

  iterator addBasicBlock(BlockT *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(BlockT *BB);

  void addToFrontier(iterator I, BlockT *Node);

  void removeFromFrontier(iterator I, BlockT *Node);

  /// compareDomSet - Return false if two domsets match. Otherwise
  /// return true;
  bool compareDomSet(DomSetType &DS1, const DomSetType &DS2) const;

  /// compare - Return true if the other dominance frontier base matches
  /// this dominance frontier base. Otherwise return false.
  bool compare(DominanceFrontierBase<BlockT> &Other) const;

  /// print - Convert to human readable form
  ///
  void print(raw_ostream &OS) const;

  /// 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.
///
template <class BlockT>
class ForwardDominanceFrontierBase : public DominanceFrontierBase<BlockT> {
private:
  typedef GraphTraits<BlockT *> BlockTraits;

public:
  typedef DominatorTreeBase<BlockT> DomTreeT;
  typedef DomTreeNodeBase<BlockT> DomTreeNodeT;
  typedef typename DominanceFrontierBase<BlockT>::DomSetType DomSetType;

  ForwardDominanceFrontierBase() : DominanceFrontierBase<BlockT>(false) {}

  void analyze(DomTreeT &DT) {
    this->Roots = DT.getRoots();
    assert(this->Roots.size() == 1 &&
           "Only one entry block for forward domfronts!");
    calculate(DT, DT[this->Roots[0]]);
  }

  const DomSetType &calculate(const DomTreeT &DT, const DomTreeNodeT *Node);
};

class DominanceFrontier : public FunctionPass {
  ForwardDominanceFrontierBase<BasicBlock> Base;

public:
  typedef DominatorTreeBase<BasicBlock> DomTreeT;
  typedef DomTreeNodeBase<BasicBlock> DomTreeNodeT;
  typedef DominanceFrontierBase<BasicBlock>::DomSetType DomSetType;
  typedef DominanceFrontierBase<BasicBlock>::iterator iterator;
  typedef DominanceFrontierBase<BasicBlock>::const_iterator const_iterator;

  static char ID; // Pass ID, replacement for typeid

  DominanceFrontier();

  ForwardDominanceFrontierBase<BasicBlock> &getBase() { return Base; }

  inline const std::vector<BasicBlock *> &getRoots() const {
    return Base.getRoots();
  }

  BasicBlock *getRoot() const { return Base.getRoot(); }

  bool isPostDominator() const { return Base.isPostDominator(); }

  iterator begin() { return Base.begin(); }

  const_iterator begin() const { return Base.begin(); }

  iterator end() { return Base.end(); }

  const_iterator end() const { return Base.end(); }

  iterator find(BasicBlock *B) { return Base.find(B); }

  const_iterator find(BasicBlock *B) const { return Base.find(B); }

  iterator addBasicBlock(BasicBlock *BB, const DomSetType &frontier) {
    return Base.addBasicBlock(BB, frontier);
  }

  void removeBlock(BasicBlock *BB) { return Base.removeBlock(BB); }

  void addToFrontier(iterator I, BasicBlock *Node) {
    return Base.addToFrontier(I, Node);
  }

  void removeFromFrontier(iterator I, BasicBlock *Node) {
    return Base.removeFromFrontier(I, Node);
  }

  bool compareDomSet(DomSetType &DS1, const DomSetType &DS2) const {
    return Base.compareDomSet(DS1, DS2);
  }

  bool compare(DominanceFrontierBase<BasicBlock> &Other) const {
    return Base.compare(Other);
  }

  void releaseMemory() override;

  bool runOnFunction(Function &) override;

  void getAnalysisUsage(AnalysisUsage &AU) const override;

  void print(raw_ostream &OS, const Module * = nullptr) const override;

  void dump() const;
};

EXTERN_TEMPLATE_INSTANTIATION(class DominanceFrontierBase<BasicBlock>);
EXTERN_TEMPLATE_INSTANTIATION(class ForwardDominanceFrontierBase<BasicBlock>);

} // End llvm namespace

#endif