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 // FIXME: Replace this brittle forward declaration with the include of the new
35 // PassManager.h when doing so doesn't break the PassManagerBuilder.
36 template <typename IRUnitT> class AnalysisManager;
37 class PreservedAnalyses;
39 extern template class DomTreeNodeBase<BasicBlock>;
40 extern template class DominatorTreeBase<BasicBlock>;
42 extern template void Calculate<Function, BasicBlock *>(
43 DominatorTreeBase<GraphTraits<BasicBlock *>::NodeType> &DT, Function &F);
44 extern template void Calculate<Function, Inverse<BasicBlock *>>(
45 DominatorTreeBase<GraphTraits<Inverse<BasicBlock *>>::NodeType> &DT,
48 typedef DomTreeNodeBase<BasicBlock> DomTreeNode;
50 class BasicBlockEdge {
51 const BasicBlock *Start;
52 const BasicBlock *End;
54 BasicBlockEdge(const BasicBlock *Start_, const BasicBlock *End_) :
55 Start(Start_), End(End_) { }
56 const BasicBlock *getStart() const {
59 const BasicBlock *getEnd() const {
62 bool isSingleEdge() const;
65 /// \brief Concrete subclass of DominatorTreeBase that is used to compute a
66 /// normal dominator tree.
67 class DominatorTree : public DominatorTreeBase<BasicBlock> {
69 typedef DominatorTreeBase<BasicBlock> Base;
71 DominatorTree() : DominatorTreeBase<BasicBlock>(false) {}
72 explicit DominatorTree(Function &F) : DominatorTreeBase<BasicBlock>(false) {
76 DominatorTree(DominatorTree &&Arg)
77 : Base(std::move(static_cast<Base &>(Arg))) {}
78 DominatorTree &operator=(DominatorTree &&RHS) {
79 Base::operator=(std::move(static_cast<Base &>(RHS)));
83 /// \brief Returns *false* if the other dominator tree matches this dominator
85 inline bool compare(const DominatorTree &Other) const {
86 const DomTreeNode *R = getRootNode();
87 const DomTreeNode *OtherR = Other.getRootNode();
89 if (!R || !OtherR || R->getBlock() != OtherR->getBlock())
92 if (Base::compare(Other))
98 // Ensure base-class overloads are visible.
99 using Base::dominates;
101 /// \brief Return true if Def dominates a use in User.
103 /// This performs the special checks necessary if Def and User are in the same
104 /// basic block. Note that Def doesn't dominate a use in Def itself!
105 bool dominates(const Instruction *Def, const Use &U) const;
106 bool dominates(const Instruction *Def, const Instruction *User) const;
107 bool dominates(const Instruction *Def, const BasicBlock *BB) const;
108 bool dominates(const BasicBlockEdge &BBE, const Use &U) const;
109 bool dominates(const BasicBlockEdge &BBE, const BasicBlock *BB) const;
111 // Ensure base class overloads are visible.
112 using Base::isReachableFromEntry;
114 /// \brief Provide an overload for a Use.
115 bool isReachableFromEntry(const Use &U) const;
117 /// \brief Verify the correctness of the domtree by re-computing it.
119 /// This should only be used for debugging as it aborts the program if the
120 /// verification fails.
121 void verifyDomTree() const;
124 //===-------------------------------------
125 // DominatorTree GraphTraits specializations so the DominatorTree can be
126 // iterable by generic graph iterators.
128 template <class Node, class ChildIterator> struct DomTreeGraphTraitsBase {
129 typedef Node NodeType;
130 typedef ChildIterator ChildIteratorType;
131 typedef df_iterator<Node *, SmallPtrSet<NodeType *, 8>> nodes_iterator;
133 static NodeType *getEntryNode(NodeType *N) { return N; }
134 static inline ChildIteratorType child_begin(NodeType *N) {
137 static inline ChildIteratorType child_end(NodeType *N) { return N->end(); }
139 static nodes_iterator nodes_begin(NodeType *N) {
140 return df_begin(getEntryNode(N));
143 static nodes_iterator nodes_end(NodeType *N) {
144 return df_end(getEntryNode(N));
149 struct GraphTraits<DomTreeNode *>
150 : public DomTreeGraphTraitsBase<DomTreeNode, DomTreeNode::iterator> {};
153 struct GraphTraits<const DomTreeNode *>
154 : public DomTreeGraphTraitsBase<const DomTreeNode,
155 DomTreeNode::const_iterator> {};
157 template <> struct GraphTraits<DominatorTree*>
158 : public GraphTraits<DomTreeNode*> {
159 static NodeType *getEntryNode(DominatorTree *DT) {
160 return DT->getRootNode();
163 static nodes_iterator nodes_begin(DominatorTree *N) {
164 return df_begin(getEntryNode(N));
167 static nodes_iterator nodes_end(DominatorTree *N) {
168 return df_end(getEntryNode(N));
172 /// \brief Analysis pass which computes a \c DominatorTree.
173 class DominatorTreeAnalysis {
175 /// \brief Provide the result typedef for this analysis pass.
176 typedef DominatorTree Result;
178 /// \brief Opaque, unique identifier for this analysis pass.
179 static void *ID() { return (void *)&PassID; }
181 /// \brief Run the analysis pass over a function and produce a dominator tree.
182 DominatorTree run(Function &F);
184 /// \brief Provide access to a name for this pass for debugging purposes.
185 static StringRef name() { return "DominatorTreeAnalysis"; }
191 /// \brief Printer pass for the \c DominatorTree.
192 class DominatorTreePrinterPass {
196 explicit DominatorTreePrinterPass(raw_ostream &OS);
197 PreservedAnalyses run(Function &F, AnalysisManager<Function> *AM);
199 static StringRef name() { return "DominatorTreePrinterPass"; }
202 /// \brief Verifier pass for the \c DominatorTree.
203 struct DominatorTreeVerifierPass {
204 PreservedAnalyses run(Function &F, AnalysisManager<Function> *AM);
206 static StringRef name() { return "DominatorTreeVerifierPass"; }
209 /// \brief Legacy analysis pass which computes a \c DominatorTree.
210 class DominatorTreeWrapperPass : public FunctionPass {
216 DominatorTreeWrapperPass() : FunctionPass(ID) {
217 initializeDominatorTreeWrapperPassPass(*PassRegistry::getPassRegistry());
220 DominatorTree &getDomTree() { return DT; }
221 const DominatorTree &getDomTree() const { return DT; }
223 bool runOnFunction(Function &F) override;
225 void verifyAnalysis() const override;
227 void getAnalysisUsage(AnalysisUsage &AU) const override {
228 AU.setPreservesAll();
231 void releaseMemory() override { DT.releaseMemory(); }
233 void print(raw_ostream &OS, const Module *M = nullptr) const override;
236 } // End llvm namespace