PostDominators.h revision 9fc5cdf77c812aaa80419036de27576d45894d0d 
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/DominanceFrontier.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    initializePostDominatorTreePass(*PassRegistry::getPassRegistry());
30    DT = new DominatorTreeBase<BasicBlock>(true);
31  }
32
33  ~PostDominatorTree();
34
35  virtual bool runOnFunction(Function &F);
36
37  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
38    AU.setPreservesAll();
39  }
40
41  inline const std::vector<BasicBlock*> &getRoots() const {
42    return DT->getRoots();
43  }
44
45  inline DomTreeNode *getRootNode() const {
46    return DT->getRootNode();
47  }
48
49  inline DomTreeNode *operator[](BasicBlock *BB) const {
50    return DT->getNode(BB);
51  }
52
53  inline DomTreeNode *getNode(BasicBlock *BB) const {
54    return DT->getNode(BB);
55  }
56
57  inline bool dominates(DomTreeNode* A, DomTreeNode* B) const {
58    return DT->dominates(A, B);
59  }
60
61  inline bool dominates(const BasicBlock* A, const BasicBlock* B) const {
62    return DT->dominates(A, B);
63  }
64
65  inline bool properlyDominates(const DomTreeNode* A, DomTreeNode* B) const {
66    return DT->properlyDominates(A, B);
67  }
68
69  inline bool properlyDominates(BasicBlock* A, BasicBlock* B) const {
70    return DT->properlyDominates(A, B);
71  }
72
73  inline BasicBlock *findNearestCommonDominator(BasicBlock *A, BasicBlock *B) {
74    return DT->findNearestCommonDominator(A, B);
75  }
76
77  virtual void releaseMemory() {
78    DT->releaseMemory();
79  }
80
81  virtual void print(raw_ostream &OS, const Module*) const;
82};
83
84FunctionPass* createPostDomTree();
85
86template <> struct GraphTraits<PostDominatorTree*>
87  : public GraphTraits<DomTreeNode*> {
88  static NodeType *getEntryNode(PostDominatorTree *DT) {
89    return DT->getRootNode();
90  }
91
92  static nodes_iterator nodes_begin(PostDominatorTree *N) {
93    if (getEntryNode(N))
94      return df_begin(getEntryNode(N));
95    else
96      return df_end(getEntryNode(N));
97  }
98
99  static nodes_iterator nodes_end(PostDominatorTree *N) {
100    return df_end(getEntryNode(N));
101  }
102};
103
104/// PostDominanceFrontier Class - Concrete subclass of DominanceFrontier that is
105/// used to compute the a post-dominance frontier.
106///
107struct PostDominanceFrontier : public DominanceFrontierBase {
108  static char ID;
109  PostDominanceFrontier()
110    : DominanceFrontierBase(ID, true) {
111      initializePostDominanceFrontierPass(*PassRegistry::getPassRegistry());
112    }
113
114  virtual bool runOnFunction(Function &) {
115    Frontiers.clear();
116    PostDominatorTree &DT = getAnalysis<PostDominatorTree>();
117    Roots = DT.getRoots();
118    if (const DomTreeNode *Root = DT.getRootNode())
119      calculate(DT, Root);
120    return false;
121  }
122
123  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
124    AU.setPreservesAll();
125    AU.addRequired<PostDominatorTree>();
126  }
127
128private:
129  const DomSetType &calculate(const PostDominatorTree &DT,
130                              const DomTreeNode *Node);
131};
132
133FunctionPass* createPostDomFrontier();
134
135} // End llvm namespace
136
137#endif
138