PostDominators.h revision 45cfe545ec8177262dabc70580ce05feaa1c3880 
1//=- llvm/Analysis/PostDominators.h - Post Dominator Calculation-*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file exposes interfaces to post dominance information.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_ANALYSIS_POST_DOMINATORS_H
15#define LLVM_ANALYSIS_POST_DOMINATORS_H
16
17#include "llvm/Analysis/Dominators.h"
18
19namespace llvm {
20
21/// PostDominatorTree Class - Concrete subclass of DominatorTree that is used to
22/// compute the a post-dominator tree.
23///
24struct PostDominatorTree : public FunctionPass {
25  static char ID; // Pass identification, replacement for typeid
26  DominatorTreeBase<BasicBlock>* DT;
27
28  PostDominatorTree() : FunctionPass(&ID) {
29    DT = new DominatorTreeBase<BasicBlock>(true);
30  }
31
32  ~PostDominatorTree();
33
34  virtual bool runOnFunction(Function &F);
35
36  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
37    AU.setPreservesAll();
38  }
39
40  inline const std::vector<BasicBlock*> &getRoots() const {
41    return DT->getRoots();
42  }
43
44  inline DomTreeNode *getRootNode() const {
45    return DT->getRootNode();
46  }
47
48  inline DomTreeNode *operator[](BasicBlock *BB) const {
49    return DT->getNode(BB);
50  }
51
52  inline bool properlyDominates(const DomTreeNode* A, DomTreeNode* B) const {
53    return DT->properlyDominates(A, B);
54  }
55
56  inline bool properlyDominates(BasicBlock* A, BasicBlock* B) const {
57    return DT->properlyDominates(A, B);
58  }
59
60  virtual void print(raw_ostream &OS, const Module*) const;
61};
62
63FunctionPass* createPostDomTree();
64
65/// PostDominanceFrontier Class - Concrete subclass of DominanceFrontier that is
66/// used to compute the a post-dominance frontier.
67///
68struct PostDominanceFrontier : public DominanceFrontierBase {
69  static char ID;
70  PostDominanceFrontier()
71    : DominanceFrontierBase(&ID, true) {}
72
73  virtual bool runOnFunction(Function &) {
74    Frontiers.clear();
75    PostDominatorTree &DT = getAnalysis<PostDominatorTree>();
76    Roots = DT.getRoots();
77    if (const DomTreeNode *Root = DT.getRootNode())
78      calculate(DT, Root);
79    return false;
80  }
81
82  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
83    AU.setPreservesAll();
84    AU.addRequired<PostDominatorTree>();
85  }
86
87private:
88  const DomSetType &calculate(const PostDominatorTree &DT,
89                              const DomTreeNode *Node);
90};
91
92FunctionPass* createPostDomFrontier();
93
94} // End llvm namespace
95
96#endif
97