MachineDominators.h revision e2d50046fd29cb3eb2483e080cb7c39b460fbb19 
1//=- llvm/CodeGen/MachineDominators.h - Machine Dom 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 defines classes mirroring those in llvm/Analysis/Dominators.h,
11// but for target-specific code rather than target-independent IR.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CODEGEN_MACHINEDOMINATORS_H
16#define LLVM_CODEGEN_MACHINEDOMINATORS_H
17
18#include "llvm/CodeGen/MachineBasicBlock.h"
19#include "llvm/CodeGen/MachineFunction.h"
20#include "llvm/CodeGen/MachineFunctionPass.h"
21#include "llvm/Analysis/Dominators.h"
22#include "llvm/Analysis/DominatorInternals.h"
23
24namespace llvm {
25
26template<>
27inline void DominatorTreeBase<MachineBasicBlock>::addRoot(MachineBasicBlock* MBB) {
28  this->Roots.push_back(MBB);
29}
30
31EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<MachineBasicBlock>);
32EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<MachineBasicBlock>);
33
34typedef DomTreeNodeBase<MachineBasicBlock> MachineDomTreeNode;
35
36//===-------------------------------------
37/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
38/// compute a normal dominator tree.
39///
40class MachineDominatorTree : public MachineFunctionPass {
41public:
42  static char ID; // Pass ID, replacement for typeid
43  DominatorTreeBase<MachineBasicBlock>* DT;
44
45  MachineDominatorTree();
46
47  ~MachineDominatorTree();
48
49  DominatorTreeBase<MachineBasicBlock>& getBase() { return *DT; }
50
51  virtual void getAnalysisUsage(AnalysisUsage &AU) const;
52
53  /// getRoots -  Return the root blocks of the current CFG.  This may include
54  /// multiple blocks if we are computing post dominators.  For forward
55  /// dominators, this will always be a single block (the entry node).
56  ///
57  inline const std::vector<MachineBasicBlock*> &getRoots() const {
58    return DT->getRoots();
59  }
60
61  inline MachineBasicBlock *getRoot() const {
62    return DT->getRoot();
63  }
64
65  inline MachineDomTreeNode *getRootNode() const {
66    return DT->getRootNode();
67  }
68
69  virtual bool runOnMachineFunction(MachineFunction &F);
70
71  inline bool dominates(MachineDomTreeNode* A, MachineDomTreeNode* B) const {
72    return DT->dominates(A, B);
73  }
74
75  inline bool dominates(MachineBasicBlock* A, MachineBasicBlock* B) const {
76    return DT->dominates(A, B);
77  }
78
79  // dominates - Return true if A dominates B. This performs the
80  // special checks necessary if A and B are in the same basic block.
81  bool dominates(MachineInstr *A, MachineInstr *B) const {
82    MachineBasicBlock *BBA = A->getParent(), *BBB = B->getParent();
83    if (BBA != BBB) return DT->dominates(BBA, BBB);
84
85    // Loop through the basic block until we find A or B.
86    MachineBasicBlock::iterator I = BBA->begin();
87    for (; &*I != A && &*I != B; ++I) /*empty*/;
88
89    //if(!DT.IsPostDominators) {
90      // A dominates B if it is found first in the basic block.
91      return &*I == A;
92    //} else {
93    //  // A post-dominates B if B is found first in the basic block.
94    //  return &*I == B;
95    //}
96  }
97
98  inline bool properlyDominates(const MachineDomTreeNode* A,
99                                MachineDomTreeNode* B) const {
100    return DT->properlyDominates(A, B);
101  }
102
103  inline bool properlyDominates(MachineBasicBlock* A,
104                                MachineBasicBlock* B) const {
105    return DT->properlyDominates(A, B);
106  }
107
108  /// findNearestCommonDominator - Find nearest common dominator basic block
109  /// for basic block A and B. If there is no such block then return NULL.
110  inline MachineBasicBlock *findNearestCommonDominator(MachineBasicBlock *A,
111                                                       MachineBasicBlock *B) {
112    return DT->findNearestCommonDominator(A, B);
113  }
114
115  inline MachineDomTreeNode *operator[](MachineBasicBlock *BB) const {
116    return DT->getNode(BB);
117  }
118
119  /// getNode - return the (Post)DominatorTree node for the specified basic
120  /// block.  This is the same as using operator[] on this class.
121  ///
122  inline MachineDomTreeNode *getNode(MachineBasicBlock *BB) const {
123    return DT->getNode(BB);
124  }
125
126  /// addNewBlock - Add a new node to the dominator tree information.  This
127  /// creates a new node as a child of DomBB dominator node,linking it into
128  /// the children list of the immediate dominator.
129  inline MachineDomTreeNode *addNewBlock(MachineBasicBlock *BB,
130                                         MachineBasicBlock *DomBB) {
131    return DT->addNewBlock(BB, DomBB);
132  }
133
134  /// changeImmediateDominator - This method is used to update the dominator
135  /// tree information when a node's immediate dominator changes.
136  ///
137  inline void changeImmediateDominator(MachineBasicBlock *N,
138                                       MachineBasicBlock* NewIDom) {
139    DT->changeImmediateDominator(N, NewIDom);
140  }
141
142  inline void changeImmediateDominator(MachineDomTreeNode *N,
143                                       MachineDomTreeNode* NewIDom) {
144    DT->changeImmediateDominator(N, NewIDom);
145  }
146
147  /// eraseNode - Removes a node from  the dominator tree. Block must not
148  /// dominate any other blocks. Removes node from its immediate dominator's
149  /// children list. Deletes dominator node associated with basic block BB.
150  inline void eraseNode(MachineBasicBlock *BB) {
151    DT->eraseNode(BB);
152  }
153
154  /// splitBlock - BB is split and now it has one successor. Update dominator
155  /// tree to reflect this change.
156  inline void splitBlock(MachineBasicBlock* NewBB) {
157    DT->splitBlock(NewBB);
158  }
159
160  /// isReachableFromEntry - Return true if A is dominated by the entry
161  /// block of the function containing it.
162  bool isReachableFromEntry(MachineBasicBlock *A) {
163    return DT->isReachableFromEntry(A);
164  }
165
166  virtual void releaseMemory();
167
168  virtual void print(raw_ostream &OS, const Module*) const;
169};
170
171//===-------------------------------------
172/// DominatorTree GraphTraits specialization so the DominatorTree can be
173/// iterable by generic graph iterators.
174///
175
176template<class T> struct GraphTraits;
177
178template <> struct GraphTraits<MachineDomTreeNode *> {
179  typedef MachineDomTreeNode NodeType;
180  typedef NodeType::iterator  ChildIteratorType;
181
182  static NodeType *getEntryNode(NodeType *N) {
183    return N;
184  }
185  static inline ChildIteratorType child_begin(NodeType* N) {
186    return N->begin();
187  }
188  static inline ChildIteratorType child_end(NodeType* N) {
189    return N->end();
190  }
191};
192
193template <> struct GraphTraits<MachineDominatorTree*>
194  : public GraphTraits<MachineDomTreeNode *> {
195  static NodeType *getEntryNode(MachineDominatorTree *DT) {
196    return DT->getRootNode();
197  }
198};
199
200}
201
202#endif
203