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)
88 /*empty*/ ;
89
90 //if(!DT.IsPostDominators) {
91 // A dominates B if it is found first in the basic block.
92 return &*I == A;
93 //} else {
94 // // A post-dominates B if B is found first in the basic block.
95 // return &*I == B;
96 //}
97 }
98
properlyDominates(const MachineDomTreeNode * A,MachineDomTreeNode * B)99 inline bool properlyDominates(const MachineDomTreeNode* A,
100 MachineDomTreeNode* B) const {
101 return DT->properlyDominates(A, B);
102 }
103
properlyDominates(MachineBasicBlock * A,MachineBasicBlock * B)104 inline bool properlyDominates(MachineBasicBlock* A,
105 MachineBasicBlock* B) const {
106 return DT->properlyDominates(A, B);
107 }
108
109 /// findNearestCommonDominator - Find nearest common dominator basic block
110 /// for basic block A and B. If there is no such block then return NULL.
findNearestCommonDominator(MachineBasicBlock * A,MachineBasicBlock * B)111 inline MachineBasicBlock *findNearestCommonDominator(MachineBasicBlock *A,
112 MachineBasicBlock *B) {
113 return DT->findNearestCommonDominator(A, B);
114 }
115
116 inline MachineDomTreeNode *operator[](MachineBasicBlock *BB) const {
117 return DT->getNode(BB);
118 }
119
120 /// getNode - return the (Post)DominatorTree node for the specified basic
121 /// block. This is the same as using operator[] on this class.
122 ///
getNode(MachineBasicBlock * BB)123 inline MachineDomTreeNode *getNode(MachineBasicBlock *BB) const {
124 return DT->getNode(BB);
125 }
126
127 /// addNewBlock - Add a new node to the dominator tree information. This
128 /// creates a new node as a child of DomBB dominator node,linking it into
129 /// the children list of the immediate dominator.
addNewBlock(MachineBasicBlock * BB,MachineBasicBlock * DomBB)130 inline MachineDomTreeNode *addNewBlock(MachineBasicBlock *BB,
131 MachineBasicBlock *DomBB) {
132 return DT->addNewBlock(BB, DomBB);
133 }
134
135 /// changeImmediateDominator - This method is used to update the dominator
136 /// tree information when a node's immediate dominator changes.
137 ///
changeImmediateDominator(MachineBasicBlock * N,MachineBasicBlock * NewIDom)138 inline void changeImmediateDominator(MachineBasicBlock *N,
139 MachineBasicBlock* NewIDom) {
140 DT->changeImmediateDominator(N, NewIDom);
141 }
142
changeImmediateDominator(MachineDomTreeNode * N,MachineDomTreeNode * NewIDom)143 inline void changeImmediateDominator(MachineDomTreeNode *N,
144 MachineDomTreeNode* NewIDom) {
145 DT->changeImmediateDominator(N, NewIDom);
146 }
147
148 /// eraseNode - Removes a node from the dominator tree. Block must not
149 /// dominate any other blocks. Removes node from its immediate dominator's
150 /// children list. Deletes dominator node associated with basic block BB.
eraseNode(MachineBasicBlock * BB)151 inline void eraseNode(MachineBasicBlock *BB) {
152 DT->eraseNode(BB);
153 }
154
155 /// splitBlock - BB is split and now it has one successor. Update dominator
156 /// tree to reflect this change.
splitBlock(MachineBasicBlock * NewBB)157 inline void splitBlock(MachineBasicBlock* NewBB) {
158 DT->splitBlock(NewBB);
159 }
160
161 /// isReachableFromEntry - Return true if A is dominated by the entry
162 /// block of the function containing it.
isReachableFromEntry(MachineBasicBlock * A)163 bool isReachableFromEntry(MachineBasicBlock *A) {
164 return DT->isReachableFromEntry(A);
165 }
166
167 virtual void releaseMemory();
168
169 virtual void print(raw_ostream &OS, const Module*) const;
170 };
171
172 //===-------------------------------------
173 /// DominatorTree GraphTraits specialization so the DominatorTree can be
174 /// iterable by generic graph iterators.
175 ///
176
177 template<class T> struct GraphTraits;
178
179 template <> struct GraphTraits<MachineDomTreeNode *> {
180 typedef MachineDomTreeNode NodeType;
181 typedef NodeType::iterator ChildIteratorType;
182
183 static NodeType *getEntryNode(NodeType *N) {
184 return N;
185 }
186 static inline ChildIteratorType child_begin(NodeType* N) {
187 return N->begin();
188 }
189 static inline ChildIteratorType child_end(NodeType* N) {
190 return N->end();
191 }
192 };
193
194 template <> struct GraphTraits<MachineDominatorTree*>
195 : public GraphTraits<MachineDomTreeNode *> {
196 static NodeType *getEntryNode(MachineDominatorTree *DT) {
197 return DT->getRootNode();
198 }
199 };
200
201 }
202
203 #endif
204