//=- llvm/Analysis/PostDominators.h - Post Dominator Calculation --*- C++ -*-=//

//

//                     The LLVM Compiler Infrastructure

//

// This file is distributed under the University of Illinois Open Source

// License. See LICENSE.TXT for details.

//

//===----------------------------------------------------------------------===//

//

// This file exposes interfaces to post dominance information.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_ANALYSIS_POSTDOMINATORS_H

#define LLVM_ANALYSIS_POSTDOMINATORS_H

#include "llvm/ADT/DepthFirstIterator.h"

#include "llvm/IR/Dominators.h"

#include "llvm/IR/PassManager.h"

#include "llvm/Pass.h"

namespace llvm {

class Function;

class raw_ostream;

/// PostDominatorTree Class - Concrete subclass of DominatorTree that is used to

/// compute the post-dominator tree.

class PostDominatorTree : public PostDomTreeBase<BasicBlock> {

public:

  using Base = PostDomTreeBase<BasicBlock>;

  PostDominatorTree() = default;

  explicit PostDominatorTree(Function &F) { recalculate(F); }

  /// Handle invalidation explicitly.

  bool invalidate(Function &F, const PreservedAnalyses &PA,

                  FunctionAnalysisManager::Invalidator &);

};

/// Analysis pass which computes a \c PostDominatorTree.

class PostDominatorTreeAnalysis

    : public AnalysisInfoMixin<PostDominatorTreeAnalysis> {

  friend AnalysisInfoMixin<PostDominatorTreeAnalysis>;

  static AnalysisKey Key;

public:

  /// Provide the result type for this analysis pass.

  using Result = PostDominatorTree;

  /// Run the analysis pass over a function and produce a post dominator

  ///        tree.

  PostDominatorTree run(Function &F, FunctionAnalysisManager &);

};

/// Printer pass for the \c PostDominatorTree.

class PostDominatorTreePrinterPass

    : public PassInfoMixin<PostDominatorTreePrinterPass> {

  raw_ostream &OS;

public:

  explicit PostDominatorTreePrinterPass(raw_ostream &OS);

  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);

};

struct PostDominatorTreeWrapperPass : public FunctionPass {

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

  PostDominatorTree DT;

  PostDominatorTreeWrapperPass() : FunctionPass(ID) {

    initializePostDominatorTreeWrapperPassPass(*PassRegistry::getPassRegistry());

  }

  PostDominatorTree &getPostDomTree() { return DT; }

  const PostDominatorTree &getPostDomTree() const { return DT; }

  bool runOnFunction(Function &F) override;

  void verifyAnalysis() const override;

  void getAnalysisUsage(AnalysisUsage &AU) const override {

    AU.setPreservesAll();

  }

  void releaseMemory() override {

    DT.releaseMemory();

  }

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

};

FunctionPass* createPostDomTree();

template <> struct GraphTraits<PostDominatorTree*>

  : public GraphTraits<DomTreeNode*> {

  static NodeRef getEntryNode(PostDominatorTree *DT) {

    return DT->getRootNode();

  }

  static nodes_iterator nodes_begin(PostDominatorTree *N) {

    if (getEntryNode(N))

      return df_begin(getEntryNode(N));

    else

      return df_end(getEntryNode(N));

  }

  static nodes_iterator nodes_end(PostDominatorTree *N) {

    return df_end(getEntryNode(N));

  }

};

} // end namespace llvm

#endif // LLVM_ANALYSIS_POSTDOMINATORS_H