MachineDominators.h revision 1bd3271b16d7f9f0b69af00d8ff29ed00a29f9ef 
1//=- llvm/CodeGen/MachineDominators.h - Machine Dom Calculation --*- C++ -*-==//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by Owen Anderson and is distributed under
6// the University of Illinois Open Source 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/MachineFunctionPass.h"
19#include "llvm/CodeGen/MachineBasicBlock.h"
20#include "llvm/CodeGen/MachineFunction.h"
21#include "llvm/CodeGen/MachineInstr.h"
22#include "llvm/Analysis/Dominators.h"
23#include "llvm/Analysis/DominatorInternals.h"
24
25namespace llvm {
26
27inline void WriteAsOperand(std::ostream &, const MachineBasicBlock*, bool t) {  }
28
29template<>
30inline void DominatorTreeBase<MachineBasicBlock>::addRoot(MachineBasicBlock* MBB) {
31  this->Roots.push_back(MBB);
32}
33
34EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<MachineBasicBlock>);
35EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<MachineBasicBlock>);
36
37typedef DomTreeNodeBase<MachineBasicBlock> MachineDomTreeNode;
38
39//===-------------------------------------
40/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
41/// compute a normal dominator tree.
42///
43class MachineDominatorTree : public MachineFunctionPass {
44public:
45  static char ID; // Pass ID, replacement for typeid
46  DominatorTreeBase<MachineBasicBlock>* DT;
47
48  MachineDominatorTree() : MachineFunctionPass(intptr_t(&ID)) {
49    DT = new DominatorTreeBase<MachineBasicBlock>(false);
50  }
51
52  ~MachineDominatorTree() {
53    DT->releaseMemory();
54    delete DT;
55  }
56
57  /// getRoots -  Return the root blocks of the current CFG.  This may include
58  /// multiple blocks if we are computing post dominators.  For forward
59  /// dominators, this will always be a single block (the entry node).
60  ///
61  inline const std::vector<MachineBasicBlock*> &getRoots() const {
62    return DT->getRoots();
63  }
64
65  inline MachineBasicBlock *getRoot() const {
66    return DT->getRoot();
67  }
68
69  inline MachineDomTreeNode *getRootNode() const {
70    return DT->getRootNode();
71  }
72
73  virtual bool runOnMachineFunction(MachineFunction &F) {
74    DT->recalculate(F);
75
76    return false;
77  }
78
79  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
80    AU.setPreservesAll();
81  }
82
83  inline bool dominates(MachineDomTreeNode* A, MachineDomTreeNode* B) const {
84    return DT->dominates(A, B);
85  }
86
87  inline bool dominates(MachineBasicBlock* A, MachineBasicBlock* B) const {
88    return DT->dominates(A, B);
89  }
90
91  // dominates - Return true if A dominates B. This performs the
92  // special checks necessary if A and B are in the same basic block.
93  bool dominates(MachineInstr *A, MachineInstr *B) const {
94    MachineBasicBlock *BBA = A->getParent(), *BBB = B->getParent();
95    if (BBA != BBB) return DT->dominates(BBA, BBB);
96
97    // Loop through the basic block until we find A or B.
98    MachineBasicBlock::iterator I = BBA->begin();
99    for (; &*I != A && &*I != B; ++I) /*empty*/;
100
101    //if(!DT.IsPostDominators) {
102      // A dominates B if it is found first in the basic block.
103      return &*I == A;
104    //} else {
105    //  // A post-dominates B if B is found first in the basic block.
106    //  return &*I == B;
107    //}
108  }
109
110  inline bool properlyDominates(const MachineDomTreeNode* A,
111                                MachineDomTreeNode* B) const {
112    return DT->properlyDominates(A, B);
113  }
114
115  inline bool properlyDominates(MachineBasicBlock* A,
116                                MachineBasicBlock* B) const {
117    return DT->properlyDominates(A, B);
118  }
119
120  /// findNearestCommonDominator - Find nearest common dominator basic block
121  /// for basic block A and B. If there is no such block then return NULL.
122  inline MachineBasicBlock *findNearestCommonDominator(MachineBasicBlock *A,
123                                                       MachineBasicBlock *B) {
124    return DT->findNearestCommonDominator(A, B);
125  }
126
127  inline MachineDomTreeNode *operator[](MachineBasicBlock *BB) const {
128    return DT->getNode(BB);
129  }
130
131  /// getNode - return the (Post)DominatorTree node for the specified basic
132  /// block.  This is the same as using operator[] on this class.
133  ///
134  inline MachineDomTreeNode *getNode(MachineBasicBlock *BB) const {
135    return DT->getNode(BB);
136  }
137
138  /// addNewBlock - Add a new node to the dominator tree information.  This
139  /// creates a new node as a child of DomBB dominator node,linking it into
140  /// the children list of the immediate dominator.
141  inline MachineDomTreeNode *addNewBlock(MachineBasicBlock *BB,
142                                         MachineBasicBlock *DomBB) {
143    return DT->addNewBlock(BB, DomBB);
144  }
145
146  /// changeImmediateDominator - This method is used to update the dominator
147  /// tree information when a node's immediate dominator changes.
148  ///
149  inline void changeImmediateDominator(MachineBasicBlock *N,
150                                       MachineBasicBlock* NewIDom) {
151    DT->changeImmediateDominator(N, NewIDom);
152  }
153
154  inline void changeImmediateDominator(MachineDomTreeNode *N,
155                                       MachineDomTreeNode* NewIDom) {
156    DT->changeImmediateDominator(N, NewIDom);
157  }
158
159  /// eraseNode - Removes a node from  the dominator tree. Block must not
160  /// domiante any other blocks. Removes node from its immediate dominator's
161  /// children list. Deletes dominator node associated with basic block BB.
162  inline void eraseNode(MachineBasicBlock *BB) {
163    DT->eraseNode(BB);
164  }
165
166  /// splitBlock - BB is split and now it has one successor. Update dominator
167  /// tree to reflect this change.
168  inline void splitBlock(MachineBasicBlock* NewBB) {
169    DT->splitBlock(NewBB);
170  }
171
172
173  virtual void releaseMemory() {
174    DT->releaseMemory();
175  }
176
177  virtual void print(std::ostream &OS, const Module* M= 0) const {
178    DT->print(OS, M);
179  }
180};
181
182}
183
184#endif
185