MachineDominators.h revision 45cfe545ec8177262dabc70580ce05feaa1c3880 
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
26inline void WriteAsOperand(raw_ostream &, const MachineBasicBlock*, bool t) {  }
27
28template<>
29inline void DominatorTreeBase<MachineBasicBlock>::addRoot(MachineBasicBlock* MBB) {
30  this->Roots.push_back(MBB);
31}
32
33EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<MachineBasicBlock>);
34EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<MachineBasicBlock>);
35
36typedef DomTreeNodeBase<MachineBasicBlock> MachineDomTreeNode;
37
38//===-------------------------------------
39/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
40/// compute a normal dominator tree.
41///
42class MachineDominatorTree : public MachineFunctionPass {
43public:
44  static char ID; // Pass ID, replacement for typeid
45  DominatorTreeBase<MachineBasicBlock>* DT;
46
47  MachineDominatorTree();
48
49  ~MachineDominatorTree();
50
51  DominatorTreeBase<MachineBasicBlock>& getBase() { return *DT; }
52
53  virtual void getAnalysisUsage(AnalysisUsage &AU) const;
54
55  /// getRoots -  Return the root blocks of the current CFG.  This may include
56  /// multiple blocks if we are computing post dominators.  For forward
57  /// dominators, this will always be a single block (the entry node).
58  ///
59  inline const std::vector<MachineBasicBlock*> &getRoots() const {
60    return DT->getRoots();
61  }
62
63  inline MachineBasicBlock *getRoot() const {
64    return DT->getRoot();
65  }
66
67  inline MachineDomTreeNode *getRootNode() const {
68    return DT->getRootNode();
69  }
70
71  virtual bool runOnMachineFunction(MachineFunction &F);
72
73  inline bool dominates(MachineDomTreeNode* A, MachineDomTreeNode* B) const {
74    return DT->dominates(A, B);
75  }
76
77  inline bool dominates(MachineBasicBlock* A, MachineBasicBlock* B) const {
78    return DT->dominates(A, B);
79  }
80
81  // dominates - Return true if A dominates B. This performs the
82  // special checks necessary if A and B are in the same basic block.
83  bool dominates(MachineInstr *A, MachineInstr *B) const {
84    MachineBasicBlock *BBA = A->getParent(), *BBB = B->getParent();
85    if (BBA != BBB) return DT->dominates(BBA, BBB);
86
87    // Loop through the basic block until we find A or B.
88    MachineBasicBlock::iterator I = BBA->begin();
89    for (; &*I != A && &*I != B; ++I) /*empty*/;
90
91    //if(!DT.IsPostDominators) {
92      // A dominates B if it is found first in the basic block.
93      return &*I == A;
94    //} else {
95    //  // A post-dominates B if B is found first in the basic block.
96    //  return &*I == B;
97    //}
98  }
99
100  inline bool properlyDominates(const MachineDomTreeNode* A,
101                                MachineDomTreeNode* B) const {
102    return DT->properlyDominates(A, B);
103  }
104
105  inline bool properlyDominates(MachineBasicBlock* A,
106                                MachineBasicBlock* B) const {
107    return DT->properlyDominates(A, B);
108  }
109
110  /// findNearestCommonDominator - Find nearest common dominator basic block
111  /// for basic block A and B. If there is no such block then return NULL.
112  inline MachineBasicBlock *findNearestCommonDominator(MachineBasicBlock *A,
113                                                       MachineBasicBlock *B) {
114    return DT->findNearestCommonDominator(A, B);
115  }
116
117  inline MachineDomTreeNode *operator[](MachineBasicBlock *BB) const {
118    return DT->getNode(BB);
119  }
120
121  /// getNode - return the (Post)DominatorTree node for the specified basic
122  /// block.  This is the same as using operator[] on this class.
123  ///
124  inline MachineDomTreeNode *getNode(MachineBasicBlock *BB) const {
125    return DT->getNode(BB);
126  }
127
128  /// addNewBlock - Add a new node to the dominator tree information.  This
129  /// creates a new node as a child of DomBB dominator node,linking it into
130  /// the children list of the immediate dominator.
131  inline MachineDomTreeNode *addNewBlock(MachineBasicBlock *BB,
132                                         MachineBasicBlock *DomBB) {
133    return DT->addNewBlock(BB, DomBB);
134  }
135
136  /// changeImmediateDominator - This method is used to update the dominator
137  /// tree information when a node's immediate dominator changes.
138  ///
139  inline void changeImmediateDominator(MachineBasicBlock *N,
140                                       MachineBasicBlock* NewIDom) {
141    DT->changeImmediateDominator(N, NewIDom);
142  }
143
144  inline void changeImmediateDominator(MachineDomTreeNode *N,
145                                       MachineDomTreeNode* NewIDom) {
146    DT->changeImmediateDominator(N, NewIDom);
147  }
148
149  /// eraseNode - Removes a node from  the dominator tree. Block must not
150  /// domiante any other blocks. Removes node from its immediate dominator's
151  /// children list. Deletes dominator node associated with basic block BB.
152  inline void eraseNode(MachineBasicBlock *BB) {
153    DT->eraseNode(BB);
154  }
155
156  /// splitBlock - BB is split and now it has one successor. Update dominator
157  /// tree to reflect this change.
158  inline void splitBlock(MachineBasicBlock* NewBB) {
159    DT->splitBlock(NewBB);
160  }
161
162
163  virtual void releaseMemory();
164
165  virtual void print(raw_ostream &OS, const Module*) const;
166};
167
168//===-------------------------------------
169/// DominatorTree GraphTraits specialization so the DominatorTree can be
170/// iterable by generic graph iterators.
171///
172
173template<class T> struct GraphTraits;
174
175template <> struct GraphTraits<MachineDomTreeNode *> {
176  typedef MachineDomTreeNode NodeType;
177  typedef NodeType::iterator  ChildIteratorType;
178
179  static NodeType *getEntryNode(NodeType *N) {
180    return N;
181  }
182  static inline ChildIteratorType child_begin(NodeType* N) {
183    return N->begin();
184  }
185  static inline ChildIteratorType child_end(NodeType* N) {
186    return N->end();
187  }
188};
189
190template <> struct GraphTraits<MachineDominatorTree*>
191  : public GraphTraits<MachineDomTreeNode *> {
192  static NodeType *getEntryNode(MachineDominatorTree *DT) {
193    return DT->getRootNode();
194  }
195};
196
197}
198
199#endif
200