1 //===- Dominators.h - Dominator Info Calculation ----------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the DominatorTree class, which provides fast and efficient
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_IR_DOMINATORS_H
16 #define LLVM_IR_DOMINATORS_H
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/DepthFirstIterator.h"
20 #include "llvm/ADT/GraphTraits.h"
21 #include "llvm/ADT/SmallPtrSet.h"
22 #include "llvm/ADT/SmallVector.h"
23 #include "llvm/IR/BasicBlock.h"
24 #include "llvm/IR/CFG.h"
25 #include "llvm/IR/Function.h"
26 #include "llvm/Pass.h"
27 #include "llvm/Support/Compiler.h"
28 #include "llvm/Support/GenericDomTree.h"
29 #include "llvm/Support/raw_ostream.h"
34 EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<BasicBlock>);
35 EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<BasicBlock>);
38 EXTERN_TEMPLATE_INSTANTIATION(void Calculate<Function LLVM_COMMA BasicBlock *>(
39 DominatorTreeBase<GraphTraits<BasicBlock *>::NodeType> &DT LLVM_COMMA
41 EXTERN_TEMPLATE_INSTANTIATION(
42 void Calculate<Function LLVM_COMMA Inverse<BasicBlock *> >(
43 DominatorTreeBase<GraphTraits<Inverse<BasicBlock *> >::NodeType> &DT
44 LLVM_COMMA Function &F));
47 typedef DomTreeNodeBase<BasicBlock> DomTreeNode;
49 class BasicBlockEdge {
50 const BasicBlock *Start;
51 const BasicBlock *End;
53 BasicBlockEdge(const BasicBlock *Start_, const BasicBlock *End_) :
54 Start(Start_), End(End_) { }
55 const BasicBlock *getStart() const {
58 const BasicBlock *getEnd() const {
61 bool isSingleEdge() const;
64 /// \brief Concrete subclass of DominatorTreeBase that is used to compute a
65 /// normal dominator tree.
66 class DominatorTree : public DominatorTreeBase<BasicBlock> {
68 typedef DominatorTreeBase<BasicBlock> Base;
70 DominatorTree() : DominatorTreeBase<BasicBlock>(false) {}
72 /// \brief Returns *false* if the other dominator tree matches this dominator
74 inline bool compare(const DominatorTree &Other) const {
75 const DomTreeNode *R = getRootNode();
76 const DomTreeNode *OtherR = Other.getRootNode();
78 if (!R || !OtherR || R->getBlock() != OtherR->getBlock())
81 if (Base::compare(Other))
87 // Ensure base-class overloads are visible.
88 using Base::dominates;
90 /// \brief Return true if Def dominates a use in User.
92 /// This performs the special checks necessary if Def and User are in the same
93 /// basic block. Note that Def doesn't dominate a use in Def itself!
94 bool dominates(const Instruction *Def, const Use &U) const;
95 bool dominates(const Instruction *Def, const Instruction *User) const;
96 bool dominates(const Instruction *Def, const BasicBlock *BB) const;
97 bool dominates(const BasicBlockEdge &BBE, const Use &U) const;
98 bool dominates(const BasicBlockEdge &BBE, const BasicBlock *BB) const;
100 // Ensure base class overloads are visible.
101 using Base::isReachableFromEntry;
103 /// \brief Provide an overload for a Use.
104 bool isReachableFromEntry(const Use &U) const;
106 /// \brief Verify the correctness of the domtree by re-computing it.
108 /// This should only be used for debugging as it aborts the program if the
109 /// verification fails.
110 void verifyDomTree() const;
113 //===-------------------------------------
114 // DominatorTree GraphTraits specializations so the DominatorTree can be
115 // iterable by generic graph iterators.
117 template <> struct GraphTraits<DomTreeNode*> {
118 typedef DomTreeNode NodeType;
119 typedef NodeType::iterator ChildIteratorType;
121 static NodeType *getEntryNode(NodeType *N) {
124 static inline ChildIteratorType child_begin(NodeType *N) {
127 static inline ChildIteratorType child_end(NodeType *N) {
131 typedef df_iterator<DomTreeNode*> nodes_iterator;
133 static nodes_iterator nodes_begin(DomTreeNode *N) {
134 return df_begin(getEntryNode(N));
137 static nodes_iterator nodes_end(DomTreeNode *N) {
138 return df_end(getEntryNode(N));
142 template <> struct GraphTraits<DominatorTree*>
143 : public GraphTraits<DomTreeNode*> {
144 static NodeType *getEntryNode(DominatorTree *DT) {
145 return DT->getRootNode();
148 static nodes_iterator nodes_begin(DominatorTree *N) {
149 return df_begin(getEntryNode(N));
152 static nodes_iterator nodes_end(DominatorTree *N) {
153 return df_end(getEntryNode(N));
157 /// \brief Analysis pass which computes a \c DominatorTree.
158 class DominatorTreeWrapperPass : public FunctionPass {
164 DominatorTreeWrapperPass() : FunctionPass(ID) {
165 initializeDominatorTreeWrapperPassPass(*PassRegistry::getPassRegistry());
168 DominatorTree &getDomTree() { return DT; }
169 const DominatorTree &getDomTree() const { return DT; }
171 bool runOnFunction(Function &F) override;
173 void verifyAnalysis() const override;
175 void getAnalysisUsage(AnalysisUsage &AU) const override {
176 AU.setPreservesAll();
179 void releaseMemory() override { DT.releaseMemory(); }
181 void print(raw_ostream &OS, const Module *M = nullptr) const override;
184 } // End llvm namespace