PostDominators.h revision 2833fac27324b956cfb31be987652d2304d10761 
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 dominates(DomTreeNode* A, DomTreeNode* B) const {
53    return DT->dominates(A, B);
54  }
55
56  inline bool dominates(const BasicBlock* A, const BasicBlock* B) const {
57    return DT->dominates(A, B);
58  }
59
60  inline bool properlyDominates(const DomTreeNode* A, DomTreeNode* B) const {
61    return DT->properlyDominates(A, B);
62  }
63
64  inline bool properlyDominates(BasicBlock* A, BasicBlock* B) const {
65    return DT->properlyDominates(A, B);
66  }
67
68  virtual void releaseMemory() {
69    DT->releaseMemory();
70  }
71
72  virtual void print(raw_ostream &OS, const Module*) const;
73};
74
75FunctionPass* createPostDomTree();
76
77template <> struct GraphTraits<PostDominatorTree*>
78  : public GraphTraits<DomTreeNode*> {
79  static NodeType *getEntryNode(PostDominatorTree *DT) {
80    return DT->getRootNode();
81  }
82
83  static nodes_iterator nodes_begin(PostDominatorTree *N) {
84    if (getEntryNode(N))
85      return df_begin(getEntryNode(N));
86    else
87      return df_end(getEntryNode(N));
88  }
89
90  static nodes_iterator nodes_end(PostDominatorTree *N) {
91    return df_end(getEntryNode(N));
92  }
93};
94
95/// PostDominanceFrontier Class - Concrete subclass of DominanceFrontier that is
96/// used to compute the a post-dominance frontier.
97///
98struct PostDominanceFrontier : public DominanceFrontierBase {
99  static char ID;
100  PostDominanceFrontier()
101    : DominanceFrontierBase(&ID, true) {}
102
103  virtual bool runOnFunction(Function &) {
104    Frontiers.clear();
105    PostDominatorTree &DT = getAnalysis<PostDominatorTree>();
106    Roots = DT.getRoots();
107    if (const DomTreeNode *Root = DT.getRootNode())
108      calculate(DT, Root);
109    return false;
110  }
111
112  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
113    AU.setPreservesAll();
114    AU.addRequired<PostDominatorTree>();
115  }
116
117private:
118  const DomSetType &calculate(const PostDominatorTree &DT,
119                              const DomTreeNode *Node);
120};
121
122FunctionPass* createPostDomFrontier();
123
124} // End llvm namespace
125
126#endif
127