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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 
24 namespace llvm {
25 
26 template<>
addRoot(MachineBasicBlock * MBB)27 inline void DominatorTreeBase<MachineBasicBlock>::addRoot(MachineBasicBlock* MBB) {
28   this->Roots.push_back(MBB);
29 }
30 
31 EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<MachineBasicBlock>);
32 EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<MachineBasicBlock>);
33 
34 typedef DomTreeNodeBase<MachineBasicBlock> MachineDomTreeNode;
35 
36 //===-------------------------------------
37 /// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
38 /// compute a normal dominator tree.
39 ///
40 class MachineDominatorTree : public MachineFunctionPass {
41 public:
42   static char ID; // Pass ID, replacement for typeid
43   DominatorTreeBase<MachineBasicBlock>* DT;
44 
45   MachineDominatorTree();
46 
47   ~MachineDominatorTree();
48 
getBase()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   ///
getRoots()57   inline const std::vector<MachineBasicBlock*> &getRoots() const {
58     return DT->getRoots();
59   }
60 
getRoot()61   inline MachineBasicBlock *getRoot() const {
62     return DT->getRoot();
63   }
64 
getRootNode()65   inline MachineDomTreeNode *getRootNode() const {
66     return DT->getRootNode();
67   }
68 
69   virtual bool runOnMachineFunction(MachineFunction &F);
70 
dominates(MachineDomTreeNode * A,MachineDomTreeNode * B)71   inline bool dominates(MachineDomTreeNode* A, MachineDomTreeNode* B) const {
72     return DT->dominates(A, B);
73   }
74 
dominates(MachineBasicBlock * A,MachineBasicBlock * B)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.
dominates(MachineInstr * A,MachineInstr * B)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 
properlyDominates(const MachineDomTreeNode * A,MachineDomTreeNode * B)98   inline bool properlyDominates(const MachineDomTreeNode* A,
99                                 MachineDomTreeNode* B) const {
100     return DT->properlyDominates(A, B);
101   }
102 
properlyDominates(MachineBasicBlock * A,MachineBasicBlock * B)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.
findNearestCommonDominator(MachineBasicBlock * A,MachineBasicBlock * B)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   ///
getNode(MachineBasicBlock * BB)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.
addNewBlock(MachineBasicBlock * BB,MachineBasicBlock * DomBB)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   ///
changeImmediateDominator(MachineBasicBlock * N,MachineBasicBlock * NewIDom)137   inline void changeImmediateDominator(MachineBasicBlock *N,
138                                        MachineBasicBlock* NewIDom) {
139     DT->changeImmediateDominator(N, NewIDom);
140   }
141 
changeImmediateDominator(MachineDomTreeNode * N,MachineDomTreeNode * NewIDom)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.
eraseNode(MachineBasicBlock * 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.
splitBlock(MachineBasicBlock * NewBB)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.
isReachableFromEntry(MachineBasicBlock * A)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 
176 template<class T> struct GraphTraits;
177 
178 template <> 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 
193 template <> 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