Dominators.h revision 1b226abcd97598b40b8b801593b168dcd201cdde
1168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat//===- llvm/Analysis/Dominators.h - Dominator Info Calculation --*- C++ -*-===// 2168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// 3168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// The LLVM Compiler Infrastructure 4168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// 5168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// This file is distributed under the University of Illinois Open Source 6168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// License. See LICENSE.TXT for details. 7168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// 8168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat//===----------------------------------------------------------------------===// 9168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// 10168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// This file defines the following classes: 11168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// 1. DominatorTree: Represent dominators as an explicit tree structure. 12168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// 2. DominanceFrontier: Calculate and hold the dominance frontier for a 13168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// function. 14168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// 15168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// These data structures are listed in increasing order of complexity. It 16168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// takes longer to calculate the dominator frontier, for example, than the 17168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// DominatorTree mapping. 18168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat// 19168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat//===----------------------------------------------------------------------===// 20168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat 21168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#ifndef LLVM_ANALYSIS_DOMINATORS_H 22168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#define LLVM_ANALYSIS_DOMINATORS_H 23168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat 24168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#include "llvm/Pass.h" 25168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#include "llvm/Function.h" 26168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#include "llvm/Instructions.h" 27168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#include "llvm/ADT/DenseMap.h" 28168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#include "llvm/ADT/DepthFirstIterator.h" 29168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#include "llvm/ADT/GraphTraits.h" 30fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat#include "llvm/ADT/SmallPtrSet.h" 31168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#include "llvm/ADT/SmallVector.h" 32fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat#include "llvm/Assembly/Writer.h" 33fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat#include "llvm/Support/CFG.h" 34168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#include "llvm/Support/Compiler.h" 35168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#include "llvm/Support/raw_ostream.h" 36fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat#include <algorithm> 37fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat#include <map> 38168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat#include <set> 39168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat 40fa644ffe944c01a9b00f8d7676d58394fabee285San Mehatnamespace llvm { 41fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 42168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat//===----------------------------------------------------------------------===// 43168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat/// DominatorBase - Base class that other, more interesting dominator analyses 44fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat/// inherit from. 45fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat/// 46168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehattemplate <class NodeT> 47168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehatclass DominatorBase { 48fa644ffe944c01a9b00f8d7676d58394fabee285San Mehatprotected: 49168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat std::vector<NodeT*> Roots; 50168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat const bool IsPostDominators; 51168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat inline explicit DominatorBase(bool isPostDom) : 52168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat Roots(), IsPostDominators(isPostDom) {} 53168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehatpublic: 54168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat 55168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat /// getRoots - Return the root blocks of the current CFG. This may include 56168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat /// multiple blocks if we are computing post dominators. For forward 57168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat /// dominators, this will always be a single block (the entry node). 58168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat /// 59168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat inline const std::vector<NodeT*> &getRoots() const { return Roots; } 60168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat 61fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat /// isPostDominator - Returns true if analysis based of postdoms 62fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat /// 63fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat bool isPostDominator() const { return IsPostDominators; } 64df6c1b91e3813886070f35929583c30cfaead918San Mehat}; 65fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 66168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat 67fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat//===----------------------------------------------------------------------===// 68fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat// DomTreeNode - Dominator Tree Node 69fa644ffe944c01a9b00f8d7676d58394fabee285San Mehattemplate<class NodeT> class DominatorTreeBase; 70fa644ffe944c01a9b00f8d7676d58394fabee285San Mehatstruct PostDominatorTree; 71fa644ffe944c01a9b00f8d7676d58394fabee285San Mehatclass MachineBasicBlock; 72fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 73fa644ffe944c01a9b00f8d7676d58394fabee285San Mehattemplate <class NodeT> 74fa644ffe944c01a9b00f8d7676d58394fabee285San Mehatclass DomTreeNodeBase { 75fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat NodeT *TheBB; 76fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat DomTreeNodeBase<NodeT> *IDom; 77fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat std::vector<DomTreeNodeBase<NodeT> *> Children; 78fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat int DFSNumIn, DFSNumOut; 79fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 80fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat template<class N> friend class DominatorTreeBase; 81fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat friend struct PostDominatorTree; 82fa644ffe944c01a9b00f8d7676d58394fabee285San Mehatpublic: 83fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat typedef typename std::vector<DomTreeNodeBase<NodeT> *>::iterator iterator; 84fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat typedef typename std::vector<DomTreeNodeBase<NodeT> *>::const_iterator 85fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat const_iterator; 86fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 87fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat iterator begin() { return Children.begin(); } 88fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat iterator end() { return Children.end(); } 89dbdb0db516fa4935ff7b5c05914932099237d808San Mehat const_iterator begin() const { return Children.begin(); } 90dbdb0db516fa4935ff7b5c05914932099237d808San Mehat const_iterator end() const { return Children.end(); } 91fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 92fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat NodeT *getBlock() const { return TheBB; } 93fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat DomTreeNodeBase<NodeT> *getIDom() const { return IDom; } 94fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat const std::vector<DomTreeNodeBase<NodeT>*> &getChildren() const { 95fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat return Children; 96fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat } 97fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 98fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat DomTreeNodeBase(NodeT *BB, DomTreeNodeBase<NodeT> *iDom) 99fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat : TheBB(BB), IDom(iDom), DFSNumIn(-1), DFSNumOut(-1) { } 100fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 101fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat DomTreeNodeBase<NodeT> *addChild(DomTreeNodeBase<NodeT> *C) { 102fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat Children.push_back(C); 103fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat return C; 104168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat } 105fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 106168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat size_t getNumChildren() const { 107168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat return Children.size(); 108fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat } 109fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 110168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat void clearAllChildren() { 111168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat Children.clear(); 112fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat } 113168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat 114fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat bool compare(DomTreeNodeBase<NodeT> *Other) { 115168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat if (getNumChildren() != Other->getNumChildren()) 116168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat return true; 117fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 118fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat SmallPtrSet<NodeT *, 4> OtherChildren; 119fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat for(iterator I = Other->begin(), E = Other->end(); I != E; ++I) { 120fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat NodeT *Nd = (*I)->getBlock(); 121fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat OtherChildren.insert(Nd); 122fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat } 123fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 124fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat for(iterator I = begin(), E = end(); I != E; ++I) { 125fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat NodeT *N = (*I)->getBlock(); 126fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat if (OtherChildren.count(N) == 0) 127fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat return true; 128fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat } 129df6c1b91e3813886070f35929583c30cfaead918San Mehat return false; 130168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat } 131fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 132168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat void setIDom(DomTreeNodeBase<NodeT> *NewIDom) { 133df6c1b91e3813886070f35929583c30cfaead918San Mehat assert(IDom && "No immediate dominator?"); 134fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat if (IDom != NewIDom) { 135fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat typename std::vector<DomTreeNodeBase<NodeT>*>::iterator I = 136dbdb0db516fa4935ff7b5c05914932099237d808San Mehat std::find(IDom->Children.begin(), IDom->Children.end(), this); 137fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat assert(I != IDom->Children.end() && 138fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat "Not in immediate dominator children set!"); 139fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat // I am no longer your child... 140fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat IDom->Children.erase(I); 141fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 142fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat // Switch to new dominator 143fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat IDom = NewIDom; 144fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat IDom->Children.push_back(this); 145fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat } 146fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat } 147168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat 148fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat /// getDFSNumIn/getDFSNumOut - These are an internal implementation detail, do 149fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat /// not call them. 150fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat unsigned getDFSNumIn() const { return DFSNumIn; } 151fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat unsigned getDFSNumOut() const { return DFSNumOut; } 152fa644ffe944c01a9b00f8d7676d58394fabee285San Mehatprivate: 153fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat // Return true if this node is dominated by other. Use this only if DFS info 154fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat // is valid. 155fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat bool DominatedBy(const DomTreeNodeBase<NodeT> *other) const { 156fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat return this->DFSNumIn >= other->DFSNumIn && 157fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat this->DFSNumOut <= other->DFSNumOut; 158fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat } 159fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat}; 160fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 161fa644ffe944c01a9b00f8d7676d58394fabee285San MehatEXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<BasicBlock>); 162fa644ffe944c01a9b00f8d7676d58394fabee285San MehatEXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<MachineBasicBlock>); 163fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 164fa644ffe944c01a9b00f8d7676d58394fabee285San Mehattemplate<class NodeT> 165fa644ffe944c01a9b00f8d7676d58394fabee285San Mehatstatic raw_ostream &operator<<(raw_ostream &o, 166fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat const DomTreeNodeBase<NodeT> *Node) { 167fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat if (Node->getBlock()) 168fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat WriteAsOperand(o, Node->getBlock(), false); 169fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat else 170168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat o << " <<exit node>>"; 171fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 172fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat o << " {" << Node->getDFSNumIn() << "," << Node->getDFSNumOut() << "}"; 173168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat 174168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat return o << "\n"; 175168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehat} 176d768066ef54270a0d3ccfccd50ae8238db5a2cddSan Mehat 177fa644ffe944c01a9b00f8d7676d58394fabee285San Mehattemplate<class NodeT> 178fa644ffe944c01a9b00f8d7676d58394fabee285San Mehatstatic void PrintDomTree(const DomTreeNodeBase<NodeT> *N, raw_ostream &o, 179fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat unsigned Lev) { 180fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat o.indent(2*Lev) << "[" << Lev << "] " << N; 181d768066ef54270a0d3ccfccd50ae8238db5a2cddSan Mehat for (typename DomTreeNodeBase<NodeT>::const_iterator I = N->begin(), 182fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat E = N->end(); I != E; ++I) 183fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat PrintDomTree<NodeT>(*I, o, Lev+1); 184fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat} 185fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 186fa644ffe944c01a9b00f8d7676d58394fabee285San Mehattypedef DomTreeNodeBase<BasicBlock> DomTreeNode; 187fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 188d768066ef54270a0d3ccfccd50ae8238db5a2cddSan Mehat//===----------------------------------------------------------------------===// 189fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat/// DominatorTree - Calculate the immediate dominator tree for a function. 190fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat/// 191fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 192fa644ffe944c01a9b00f8d7676d58394fabee285San Mehattemplate<class FuncT, class N> 193d768066ef54270a0d3ccfccd50ae8238db5a2cddSan Mehatvoid Calculate(DominatorTreeBase<typename GraphTraits<N>::NodeType>& DT, 194fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat FuncT& F); 195fa644ffe944c01a9b00f8d7676d58394fabee285San Mehat 196fa644ffe944c01a9b00f8d7676d58394fabee285San Mehattemplate<class NodeT> 197fa644ffe944c01a9b00f8d7676d58394fabee285San Mehatclass DominatorTreeBase : public DominatorBase<NodeT> { 198168415b822cae1f8b54ef09c41c11a9b97b87f40San Mehatprotected: 199 typedef DenseMap<NodeT*, DomTreeNodeBase<NodeT>*> DomTreeNodeMapType; 200 DomTreeNodeMapType DomTreeNodes; 201 DomTreeNodeBase<NodeT> *RootNode; 202 203 bool DFSInfoValid; 204 unsigned int SlowQueries; 205 // Information record used during immediate dominators computation. 206 struct InfoRec { 207 unsigned DFSNum; 208 unsigned Semi; 209 unsigned Size; 210 NodeT *Label, *Child; 211 unsigned Parent, Ancestor; 212 213 std::vector<NodeT*> Bucket; 214 215 InfoRec() : DFSNum(0), Semi(0), Size(0), Label(0), Child(0), Parent(0), 216 Ancestor(0) {} 217 }; 218 219 DenseMap<NodeT*, NodeT*> IDoms; 220 221 // Vertex - Map the DFS number to the BasicBlock* 222 std::vector<NodeT*> Vertex; 223 224 // Info - Collection of information used during the computation of idoms. 225 DenseMap<NodeT*, InfoRec> Info; 226 227 void reset() { 228 for (typename DomTreeNodeMapType::iterator I = this->DomTreeNodes.begin(), 229 E = DomTreeNodes.end(); I != E; ++I) 230 delete I->second; 231 DomTreeNodes.clear(); 232 IDoms.clear(); 233 this->Roots.clear(); 234 Vertex.clear(); 235 RootNode = 0; 236 } 237 238 // NewBB is split and now it has one successor. Update dominator tree to 239 // reflect this change. 240 template<class N, class GraphT> 241 void Split(DominatorTreeBase<typename GraphT::NodeType>& DT, 242 typename GraphT::NodeType* NewBB) { 243 assert(std::distance(GraphT::child_begin(NewBB), GraphT::child_end(NewBB)) == 1 244 && "NewBB should have a single successor!"); 245 typename GraphT::NodeType* NewBBSucc = *GraphT::child_begin(NewBB); 246 247 std::vector<typename GraphT::NodeType*> PredBlocks; 248 for (typename GraphTraits<Inverse<N> >::ChildIteratorType PI = 249 GraphTraits<Inverse<N> >::child_begin(NewBB), 250 PE = GraphTraits<Inverse<N> >::child_end(NewBB); PI != PE; ++PI) 251 PredBlocks.push_back(*PI); 252 253 assert(!PredBlocks.empty() && "No predblocks??"); 254 255 bool NewBBDominatesNewBBSucc = true; 256 for (typename GraphTraits<Inverse<N> >::ChildIteratorType PI = 257 GraphTraits<Inverse<N> >::child_begin(NewBBSucc), 258 E = GraphTraits<Inverse<N> >::child_end(NewBBSucc); PI != E; ++PI) 259 if (*PI != NewBB && !DT.dominates(NewBBSucc, *PI) && 260 DT.isReachableFromEntry(*PI)) { 261 NewBBDominatesNewBBSucc = false; 262 break; 263 } 264 265 // Find NewBB's immediate dominator and create new dominator tree node for 266 // NewBB. 267 NodeT *NewBBIDom = 0; 268 unsigned i = 0; 269 for (i = 0; i < PredBlocks.size(); ++i) 270 if (DT.isReachableFromEntry(PredBlocks[i])) { 271 NewBBIDom = PredBlocks[i]; 272 break; 273 } 274 275 // It's possible that none of the predecessors of NewBB are reachable; 276 // in that case, NewBB itself is unreachable, so nothing needs to be 277 // changed. 278 if (!NewBBIDom) 279 return; 280 281 for (i = i + 1; i < PredBlocks.size(); ++i) { 282 if (DT.isReachableFromEntry(PredBlocks[i])) 283 NewBBIDom = DT.findNearestCommonDominator(NewBBIDom, PredBlocks[i]); 284 } 285 286 // Create the new dominator tree node... and set the idom of NewBB. 287 DomTreeNodeBase<NodeT> *NewBBNode = DT.addNewBlock(NewBB, NewBBIDom); 288 289 // If NewBB strictly dominates other blocks, then it is now the immediate 290 // dominator of NewBBSucc. Update the dominator tree as appropriate. 291 if (NewBBDominatesNewBBSucc) { 292 DomTreeNodeBase<NodeT> *NewBBSuccNode = DT.getNode(NewBBSucc); 293 DT.changeImmediateDominator(NewBBSuccNode, NewBBNode); 294 } 295 } 296 297public: 298 explicit DominatorTreeBase(bool isPostDom) 299 : DominatorBase<NodeT>(isPostDom), DFSInfoValid(false), SlowQueries(0) {} 300 virtual ~DominatorTreeBase() { reset(); } 301 302 // FIXME: Should remove this 303 virtual bool runOnFunction(Function &F) { return false; } 304 305 /// compare - Return false if the other dominator tree base matches this 306 /// dominator tree base. Otherwise return true. 307 bool compare(DominatorTreeBase &Other) const { 308 309 const DomTreeNodeMapType &OtherDomTreeNodes = Other.DomTreeNodes; 310 if (DomTreeNodes.size() != OtherDomTreeNodes.size()) 311 return true; 312 313 for (typename DomTreeNodeMapType::const_iterator 314 I = this->DomTreeNodes.begin(), 315 E = this->DomTreeNodes.end(); I != E; ++I) { 316 NodeT *BB = I->first; 317 typename DomTreeNodeMapType::const_iterator OI = OtherDomTreeNodes.find(BB); 318 if (OI == OtherDomTreeNodes.end()) 319 return true; 320 321 DomTreeNodeBase<NodeT>* MyNd = I->second; 322 DomTreeNodeBase<NodeT>* OtherNd = OI->second; 323 324 if (MyNd->compare(OtherNd)) 325 return true; 326 } 327 328 return false; 329 } 330 331 virtual void releaseMemory() { reset(); } 332 333 /// getNode - return the (Post)DominatorTree node for the specified basic 334 /// block. This is the same as using operator[] on this class. 335 /// 336 inline DomTreeNodeBase<NodeT> *getNode(NodeT *BB) const { 337 typename DomTreeNodeMapType::const_iterator I = DomTreeNodes.find(BB); 338 return I != DomTreeNodes.end() ? I->second : 0; 339 } 340 341 /// getRootNode - This returns the entry node for the CFG of the function. If 342 /// this tree represents the post-dominance relations for a function, however, 343 /// this root may be a node with the block == NULL. This is the case when 344 /// there are multiple exit nodes from a particular function. Consumers of 345 /// post-dominance information must be capable of dealing with this 346 /// possibility. 347 /// 348 DomTreeNodeBase<NodeT> *getRootNode() { return RootNode; } 349 const DomTreeNodeBase<NodeT> *getRootNode() const { return RootNode; } 350 351 /// properlyDominates - Returns true iff this dominates N and this != N. 352 /// Note that this is not a constant time operation! 353 /// 354 bool properlyDominates(const DomTreeNodeBase<NodeT> *A, 355 const DomTreeNodeBase<NodeT> *B) const { 356 if (A == 0 || B == 0) return false; 357 return dominatedBySlowTreeWalk(A, B); 358 } 359 360 inline bool properlyDominates(NodeT *A, NodeT *B) { 361 return properlyDominates(getNode(A), getNode(B)); 362 } 363 364 bool dominatedBySlowTreeWalk(const DomTreeNodeBase<NodeT> *A, 365 const DomTreeNodeBase<NodeT> *B) const { 366 const DomTreeNodeBase<NodeT> *IDom; 367 if (A == 0 || B == 0) return false; 368 while ((IDom = B->getIDom()) != 0 && IDom != A && IDom != B) 369 B = IDom; // Walk up the tree 370 return IDom != 0; 371 } 372 373 374 /// isReachableFromEntry - Return true if A is dominated by the entry 375 /// block of the function containing it. 376 bool isReachableFromEntry(NodeT* A) { 377 assert (!this->isPostDominator() 378 && "This is not implemented for post dominators"); 379 return dominates(&A->getParent()->front(), A); 380 } 381 382 /// dominates - Returns true iff A dominates B. Note that this is not a 383 /// constant time operation! 384 /// 385 inline bool dominates(const DomTreeNodeBase<NodeT> *A, 386 const DomTreeNodeBase<NodeT> *B) { 387 if (B == A) 388 return true; // A node trivially dominates itself. 389 390 if (A == 0 || B == 0) 391 return false; 392 393 if (DFSInfoValid) 394 return B->DominatedBy(A); 395 396 // If we end up with too many slow queries, just update the 397 // DFS numbers on the theory that we are going to keep querying. 398 SlowQueries++; 399 if (SlowQueries > 32) { 400 updateDFSNumbers(); 401 return B->DominatedBy(A); 402 } 403 404 return dominatedBySlowTreeWalk(A, B); 405 } 406 407 inline bool dominates(const NodeT *A, const NodeT *B) { 408 if (A == B) 409 return true; 410 411 // Cast away the const qualifiers here. This is ok since 412 // this function doesn't actually return the values returned 413 // from getNode. 414 return dominates(getNode(const_cast<NodeT *>(A)), 415 getNode(const_cast<NodeT *>(B))); 416 } 417 418 NodeT *getRoot() const { 419 assert(this->Roots.size() == 1 && "Should always have entry node!"); 420 return this->Roots[0]; 421 } 422 423 /// findNearestCommonDominator - Find nearest common dominator basic block 424 /// for basic block A and B. If there is no such block then return NULL. 425 NodeT *findNearestCommonDominator(NodeT *A, NodeT *B) { 426 427 assert (!this->isPostDominator() 428 && "This is not implemented for post dominators"); 429 assert (A->getParent() == B->getParent() 430 && "Two blocks are not in same function"); 431 432 // If either A or B is a entry block then it is nearest common dominator. 433 NodeT &Entry = A->getParent()->front(); 434 if (A == &Entry || B == &Entry) 435 return &Entry; 436 437 // If B dominates A then B is nearest common dominator. 438 if (dominates(B, A)) 439 return B; 440 441 // If A dominates B then A is nearest common dominator. 442 if (dominates(A, B)) 443 return A; 444 445 DomTreeNodeBase<NodeT> *NodeA = getNode(A); 446 DomTreeNodeBase<NodeT> *NodeB = getNode(B); 447 448 // Collect NodeA dominators set. 449 SmallPtrSet<DomTreeNodeBase<NodeT>*, 16> NodeADoms; 450 NodeADoms.insert(NodeA); 451 DomTreeNodeBase<NodeT> *IDomA = NodeA->getIDom(); 452 while (IDomA) { 453 NodeADoms.insert(IDomA); 454 IDomA = IDomA->getIDom(); 455 } 456 457 // Walk NodeB immediate dominators chain and find common dominator node. 458 DomTreeNodeBase<NodeT> *IDomB = NodeB->getIDom(); 459 while(IDomB) { 460 if (NodeADoms.count(IDomB) != 0) 461 return IDomB->getBlock(); 462 463 IDomB = IDomB->getIDom(); 464 } 465 466 return NULL; 467 } 468 469 //===--------------------------------------------------------------------===// 470 // API to update (Post)DominatorTree information based on modifications to 471 // the CFG... 472 473 /// addNewBlock - Add a new node to the dominator tree information. This 474 /// creates a new node as a child of DomBB dominator node,linking it into 475 /// the children list of the immediate dominator. 476 DomTreeNodeBase<NodeT> *addNewBlock(NodeT *BB, NodeT *DomBB) { 477 assert(getNode(BB) == 0 && "Block already in dominator tree!"); 478 DomTreeNodeBase<NodeT> *IDomNode = getNode(DomBB); 479 assert(IDomNode && "Not immediate dominator specified for block!"); 480 DFSInfoValid = false; 481 return DomTreeNodes[BB] = 482 IDomNode->addChild(new DomTreeNodeBase<NodeT>(BB, IDomNode)); 483 } 484 485 /// changeImmediateDominator - This method is used to update the dominator 486 /// tree information when a node's immediate dominator changes. 487 /// 488 void changeImmediateDominator(DomTreeNodeBase<NodeT> *N, 489 DomTreeNodeBase<NodeT> *NewIDom) { 490 assert(N && NewIDom && "Cannot change null node pointers!"); 491 DFSInfoValid = false; 492 N->setIDom(NewIDom); 493 } 494 495 void changeImmediateDominator(NodeT *BB, NodeT *NewBB) { 496 changeImmediateDominator(getNode(BB), getNode(NewBB)); 497 } 498 499 /// eraseNode - Removes a node from the dominator tree. Block must not 500 /// domiante any other blocks. Removes node from its immediate dominator's 501 /// children list. Deletes dominator node associated with basic block BB. 502 void eraseNode(NodeT *BB) { 503 DomTreeNodeBase<NodeT> *Node = getNode(BB); 504 assert (Node && "Removing node that isn't in dominator tree."); 505 assert (Node->getChildren().empty() && "Node is not a leaf node."); 506 507 // Remove node from immediate dominator's children list. 508 DomTreeNodeBase<NodeT> *IDom = Node->getIDom(); 509 if (IDom) { 510 typename std::vector<DomTreeNodeBase<NodeT>*>::iterator I = 511 std::find(IDom->Children.begin(), IDom->Children.end(), Node); 512 assert(I != IDom->Children.end() && 513 "Not in immediate dominator children set!"); 514 // I am no longer your child... 515 IDom->Children.erase(I); 516 } 517 518 DomTreeNodes.erase(BB); 519 delete Node; 520 } 521 522 /// removeNode - Removes a node from the dominator tree. Block must not 523 /// dominate any other blocks. Invalidates any node pointing to removed 524 /// block. 525 void removeNode(NodeT *BB) { 526 assert(getNode(BB) && "Removing node that isn't in dominator tree."); 527 DomTreeNodes.erase(BB); 528 } 529 530 /// splitBlock - BB is split and now it has one successor. Update dominator 531 /// tree to reflect this change. 532 void splitBlock(NodeT* NewBB) { 533 if (this->IsPostDominators) 534 this->Split<Inverse<NodeT*>, GraphTraits<Inverse<NodeT*> > >(*this, NewBB); 535 else 536 this->Split<NodeT*, GraphTraits<NodeT*> >(*this, NewBB); 537 } 538 539 /// print - Convert to human readable form 540 /// 541 void print(raw_ostream &o) const { 542 o << "=============================--------------------------------\n"; 543 if (this->isPostDominator()) 544 o << "Inorder PostDominator Tree: "; 545 else 546 o << "Inorder Dominator Tree: "; 547 if (this->DFSInfoValid) 548 o << "DFSNumbers invalid: " << SlowQueries << " slow queries."; 549 o << "\n"; 550 551 // The postdom tree can have a null root if there are no returns. 552 if (getRootNode()) 553 PrintDomTree<NodeT>(getRootNode(), o, 1); 554 } 555 556protected: 557 template<class GraphT> 558 friend void Compress(DominatorTreeBase<typename GraphT::NodeType>& DT, 559 typename GraphT::NodeType* VIn); 560 561 template<class GraphT> 562 friend typename GraphT::NodeType* Eval( 563 DominatorTreeBase<typename GraphT::NodeType>& DT, 564 typename GraphT::NodeType* V); 565 566 template<class GraphT> 567 friend void Link(DominatorTreeBase<typename GraphT::NodeType>& DT, 568 unsigned DFSNumV, typename GraphT::NodeType* W, 569 typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &WInfo); 570 571 template<class GraphT> 572 friend unsigned DFSPass(DominatorTreeBase<typename GraphT::NodeType>& DT, 573 typename GraphT::NodeType* V, 574 unsigned N); 575 576 template<class FuncT, class N> 577 friend void Calculate(DominatorTreeBase<typename GraphTraits<N>::NodeType>& DT, 578 FuncT& F); 579 580 /// updateDFSNumbers - Assign In and Out numbers to the nodes while walking 581 /// dominator tree in dfs order. 582 void updateDFSNumbers() { 583 unsigned DFSNum = 0; 584 585 SmallVector<std::pair<DomTreeNodeBase<NodeT>*, 586 typename DomTreeNodeBase<NodeT>::iterator>, 32> WorkStack; 587 588 for (unsigned i = 0, e = (unsigned)this->Roots.size(); i != e; ++i) { 589 DomTreeNodeBase<NodeT> *ThisRoot = getNode(this->Roots[i]); 590 WorkStack.push_back(std::make_pair(ThisRoot, ThisRoot->begin())); 591 ThisRoot->DFSNumIn = DFSNum++; 592 593 while (!WorkStack.empty()) { 594 DomTreeNodeBase<NodeT> *Node = WorkStack.back().first; 595 typename DomTreeNodeBase<NodeT>::iterator ChildIt = 596 WorkStack.back().second; 597 598 // If we visited all of the children of this node, "recurse" back up the 599 // stack setting the DFOutNum. 600 if (ChildIt == Node->end()) { 601 Node->DFSNumOut = DFSNum++; 602 WorkStack.pop_back(); 603 } else { 604 // Otherwise, recursively visit this child. 605 DomTreeNodeBase<NodeT> *Child = *ChildIt; 606 ++WorkStack.back().second; 607 608 WorkStack.push_back(std::make_pair(Child, Child->begin())); 609 Child->DFSNumIn = DFSNum++; 610 } 611 } 612 } 613 614 SlowQueries = 0; 615 DFSInfoValid = true; 616 } 617 618 DomTreeNodeBase<NodeT> *getNodeForBlock(NodeT *BB) { 619 typename DomTreeNodeMapType::iterator I = this->DomTreeNodes.find(BB); 620 if (I != this->DomTreeNodes.end() && I->second) 621 return I->second; 622 623 // Haven't calculated this node yet? Get or calculate the node for the 624 // immediate dominator. 625 NodeT *IDom = getIDom(BB); 626 627 assert(IDom || this->DomTreeNodes[NULL]); 628 DomTreeNodeBase<NodeT> *IDomNode = getNodeForBlock(IDom); 629 630 // Add a new tree node for this BasicBlock, and link it as a child of 631 // IDomNode 632 DomTreeNodeBase<NodeT> *C = new DomTreeNodeBase<NodeT>(BB, IDomNode); 633 return this->DomTreeNodes[BB] = IDomNode->addChild(C); 634 } 635 636 inline NodeT *getIDom(NodeT *BB) const { 637 typename DenseMap<NodeT*, NodeT*>::const_iterator I = IDoms.find(BB); 638 return I != IDoms.end() ? I->second : 0; 639 } 640 641 inline void addRoot(NodeT* BB) { 642 this->Roots.push_back(BB); 643 } 644 645public: 646 /// recalculate - compute a dominator tree for the given function 647 template<class FT> 648 void recalculate(FT& F) { 649 if (!this->IsPostDominators) { 650 reset(); 651 652 // Initialize roots 653 this->Roots.push_back(&F.front()); 654 this->IDoms[&F.front()] = 0; 655 this->DomTreeNodes[&F.front()] = 0; 656 this->Vertex.push_back(0); 657 658 Calculate<FT, NodeT*>(*this, F); 659 660 updateDFSNumbers(); 661 } else { 662 reset(); // Reset from the last time we were run... 663 664 // Initialize the roots list 665 for (typename FT::iterator I = F.begin(), E = F.end(); I != E; ++I) { 666 if (std::distance(GraphTraits<FT*>::child_begin(I), 667 GraphTraits<FT*>::child_end(I)) == 0) 668 addRoot(I); 669 670 // Prepopulate maps so that we don't get iterator invalidation issues later. 671 this->IDoms[I] = 0; 672 this->DomTreeNodes[I] = 0; 673 } 674 675 this->Vertex.push_back(0); 676 677 Calculate<FT, Inverse<NodeT*> >(*this, F); 678 } 679 } 680}; 681 682EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<BasicBlock>); 683 684//===------------------------------------- 685/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to 686/// compute a normal dominator tree. 687/// 688class DominatorTree : public FunctionPass { 689public: 690 static char ID; // Pass ID, replacement for typeid 691 DominatorTreeBase<BasicBlock>* DT; 692 693 DominatorTree() : FunctionPass(&ID) { 694 DT = new DominatorTreeBase<BasicBlock>(false); 695 } 696 697 ~DominatorTree() { 698 DT->releaseMemory(); 699 delete DT; 700 } 701 702 DominatorTreeBase<BasicBlock>& getBase() { return *DT; } 703 704 /// getRoots - Return the root blocks of the current CFG. This may include 705 /// multiple blocks if we are computing post dominators. For forward 706 /// dominators, this will always be a single block (the entry node). 707 /// 708 inline const std::vector<BasicBlock*> &getRoots() const { 709 return DT->getRoots(); 710 } 711 712 inline BasicBlock *getRoot() const { 713 return DT->getRoot(); 714 } 715 716 inline DomTreeNode *getRootNode() const { 717 return DT->getRootNode(); 718 } 719 720 /// compare - Return false if the other dominator tree matches this 721 /// dominator tree. Otherwise return true. 722 inline bool compare(DominatorTree &Other) const { 723 DomTreeNode *R = getRootNode(); 724 DomTreeNode *OtherR = Other.getRootNode(); 725 726 if (!R || !OtherR || R->getBlock() != OtherR->getBlock()) 727 return true; 728 729 if (DT->compare(Other.getBase())) 730 return true; 731 732 return false; 733 } 734 735 virtual bool runOnFunction(Function &F); 736 737 virtual void verifyAnalysis() const; 738 739 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 740 AU.setPreservesAll(); 741 } 742 743 inline bool dominates(DomTreeNode* A, DomTreeNode* B) const { 744 return DT->dominates(A, B); 745 } 746 747 inline bool dominates(const BasicBlock* A, const BasicBlock* B) const { 748 return DT->dominates(A, B); 749 } 750 751 // dominates - Return true if A dominates B. This performs the 752 // special checks necessary if A and B are in the same basic block. 753 bool dominates(const Instruction *A, const Instruction *B) const; 754 755 bool properlyDominates(const DomTreeNode *A, const DomTreeNode *B) const { 756 return DT->properlyDominates(A, B); 757 } 758 759 bool properlyDominates(BasicBlock *A, BasicBlock *B) const { 760 return DT->properlyDominates(A, B); 761 } 762 763 /// findNearestCommonDominator - Find nearest common dominator basic block 764 /// for basic block A and B. If there is no such block then return NULL. 765 inline BasicBlock *findNearestCommonDominator(BasicBlock *A, BasicBlock *B) { 766 return DT->findNearestCommonDominator(A, B); 767 } 768 769 inline DomTreeNode *operator[](BasicBlock *BB) const { 770 return DT->getNode(BB); 771 } 772 773 /// getNode - return the (Post)DominatorTree node for the specified basic 774 /// block. This is the same as using operator[] on this class. 775 /// 776 inline DomTreeNode *getNode(BasicBlock *BB) const { 777 return DT->getNode(BB); 778 } 779 780 /// addNewBlock - Add a new node to the dominator tree information. This 781 /// creates a new node as a child of DomBB dominator node,linking it into 782 /// the children list of the immediate dominator. 783 inline DomTreeNode *addNewBlock(BasicBlock *BB, BasicBlock *DomBB) { 784 return DT->addNewBlock(BB, DomBB); 785 } 786 787 /// changeImmediateDominator - This method is used to update the dominator 788 /// tree information when a node's immediate dominator changes. 789 /// 790 inline void changeImmediateDominator(BasicBlock *N, BasicBlock* NewIDom) { 791 DT->changeImmediateDominator(N, NewIDom); 792 } 793 794 inline void changeImmediateDominator(DomTreeNode *N, DomTreeNode* NewIDom) { 795 DT->changeImmediateDominator(N, NewIDom); 796 } 797 798 /// eraseNode - Removes a node from the dominator tree. Block must not 799 /// domiante any other blocks. Removes node from its immediate dominator's 800 /// children list. Deletes dominator node associated with basic block BB. 801 inline void eraseNode(BasicBlock *BB) { 802 DT->eraseNode(BB); 803 } 804 805 /// splitBlock - BB is split and now it has one successor. Update dominator 806 /// tree to reflect this change. 807 inline void splitBlock(BasicBlock* NewBB) { 808 DT->splitBlock(NewBB); 809 } 810 811 bool isReachableFromEntry(BasicBlock* A) { 812 return DT->isReachableFromEntry(A); 813 } 814 815 816 virtual void releaseMemory() { 817 DT->releaseMemory(); 818 } 819 820 virtual void print(raw_ostream &OS, const Module* M= 0) const; 821}; 822 823//===------------------------------------- 824/// DominatorTree GraphTraits specialization so the DominatorTree can be 825/// iterable by generic graph iterators. 826/// 827template <> struct GraphTraits<DomTreeNode*> { 828 typedef DomTreeNode NodeType; 829 typedef NodeType::iterator ChildIteratorType; 830 831 static NodeType *getEntryNode(NodeType *N) { 832 return N; 833 } 834 static inline ChildIteratorType child_begin(NodeType *N) { 835 return N->begin(); 836 } 837 static inline ChildIteratorType child_end(NodeType *N) { 838 return N->end(); 839 } 840 841 typedef df_iterator<DomTreeNode*> nodes_iterator; 842 843 static nodes_iterator nodes_begin(DomTreeNode *N) { 844 return df_begin(getEntryNode(N)); 845 } 846 847 static nodes_iterator nodes_end(DomTreeNode *N) { 848 return df_end(getEntryNode(N)); 849 } 850}; 851 852template <> struct GraphTraits<DominatorTree*> 853 : public GraphTraits<DomTreeNode*> { 854 static NodeType *getEntryNode(DominatorTree *DT) { 855 return DT->getRootNode(); 856 } 857 858 static nodes_iterator nodes_begin(DominatorTree *N) { 859 return df_begin(getEntryNode(N)); 860 } 861 862 static nodes_iterator nodes_end(DominatorTree *N) { 863 return df_end(getEntryNode(N)); 864 } 865}; 866 867 868//===----------------------------------------------------------------------===// 869/// DominanceFrontierBase - Common base class for computing forward and inverse 870/// dominance frontiers for a function. 871/// 872class DominanceFrontierBase : public FunctionPass { 873public: 874 typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb 875 typedef std::map<BasicBlock*, DomSetType> DomSetMapType; // Dom set map 876protected: 877 DomSetMapType Frontiers; 878 std::vector<BasicBlock*> Roots; 879 const bool IsPostDominators; 880 881public: 882 DominanceFrontierBase(void *ID, bool isPostDom) 883 : FunctionPass(ID), IsPostDominators(isPostDom) {} 884 885 /// getRoots - Return the root blocks of the current CFG. This may include 886 /// multiple blocks if we are computing post dominators. For forward 887 /// dominators, this will always be a single block (the entry node). 888 /// 889 inline const std::vector<BasicBlock*> &getRoots() const { return Roots; } 890 891 /// isPostDominator - Returns true if analysis based of postdoms 892 /// 893 bool isPostDominator() const { return IsPostDominators; } 894 895 virtual void releaseMemory() { Frontiers.clear(); } 896 897 // Accessor interface: 898 typedef DomSetMapType::iterator iterator; 899 typedef DomSetMapType::const_iterator const_iterator; 900 iterator begin() { return Frontiers.begin(); } 901 const_iterator begin() const { return Frontiers.begin(); } 902 iterator end() { return Frontiers.end(); } 903 const_iterator end() const { return Frontiers.end(); } 904 iterator find(BasicBlock *B) { return Frontiers.find(B); } 905 const_iterator find(BasicBlock *B) const { return Frontiers.find(B); } 906 907 iterator addBasicBlock(BasicBlock *BB, const DomSetType &frontier) { 908 assert(find(BB) == end() && "Block already in DominanceFrontier!"); 909 return Frontiers.insert(std::make_pair(BB, frontier)).first; 910 } 911 912 /// removeBlock - Remove basic block BB's frontier. 913 void removeBlock(BasicBlock *BB) { 914 assert(find(BB) != end() && "Block is not in DominanceFrontier!"); 915 for (iterator I = begin(), E = end(); I != E; ++I) 916 I->second.erase(BB); 917 Frontiers.erase(BB); 918 } 919 920 void addToFrontier(iterator I, BasicBlock *Node) { 921 assert(I != end() && "BB is not in DominanceFrontier!"); 922 I->second.insert(Node); 923 } 924 925 void removeFromFrontier(iterator I, BasicBlock *Node) { 926 assert(I != end() && "BB is not in DominanceFrontier!"); 927 assert(I->second.count(Node) && "Node is not in DominanceFrontier of BB"); 928 I->second.erase(Node); 929 } 930 931 /// compareDomSet - Return false if two domsets match. Otherwise 932 /// return true; 933 bool compareDomSet(DomSetType &DS1, const DomSetType &DS2) const { 934 std::set<BasicBlock *> tmpSet; 935 for (DomSetType::const_iterator I = DS2.begin(), 936 E = DS2.end(); I != E; ++I) 937 tmpSet.insert(*I); 938 939 for (DomSetType::const_iterator I = DS1.begin(), 940 E = DS1.end(); I != E; ) { 941 BasicBlock *Node = *I++; 942 943 if (tmpSet.erase(Node) == 0) 944 // Node is in DS1 but not in DS2. 945 return true; 946 } 947 948 if(!tmpSet.empty()) 949 // There are nodes that are in DS2 but not in DS1. 950 return true; 951 952 // DS1 and DS2 matches. 953 return false; 954 } 955 956 /// compare - Return true if the other dominance frontier base matches 957 /// this dominance frontier base. Otherwise return false. 958 bool compare(DominanceFrontierBase &Other) const { 959 DomSetMapType tmpFrontiers; 960 for (DomSetMapType::const_iterator I = Other.begin(), 961 E = Other.end(); I != E; ++I) 962 tmpFrontiers.insert(std::make_pair(I->first, I->second)); 963 964 for (DomSetMapType::iterator I = tmpFrontiers.begin(), 965 E = tmpFrontiers.end(); I != E; ) { 966 BasicBlock *Node = I->first; 967 const_iterator DFI = find(Node); 968 if (DFI == end()) 969 return true; 970 971 if (compareDomSet(I->second, DFI->second)) 972 return true; 973 974 ++I; 975 tmpFrontiers.erase(Node); 976 } 977 978 if (!tmpFrontiers.empty()) 979 return true; 980 981 return false; 982 } 983 984 /// print - Convert to human readable form 985 /// 986 virtual void print(raw_ostream &OS, const Module* = 0) const; 987}; 988 989 990//===------------------------------------- 991/// DominanceFrontier Class - Concrete subclass of DominanceFrontierBase that is 992/// used to compute a forward dominator frontiers. 993/// 994class DominanceFrontier : public DominanceFrontierBase { 995public: 996 static char ID; // Pass ID, replacement for typeid 997 DominanceFrontier() : 998 DominanceFrontierBase(&ID, false) {} 999 1000 BasicBlock *getRoot() const { 1001 assert(Roots.size() == 1 && "Should always have entry node!"); 1002 return Roots[0]; 1003 } 1004 1005 virtual bool runOnFunction(Function &) { 1006 Frontiers.clear(); 1007 DominatorTree &DT = getAnalysis<DominatorTree>(); 1008 Roots = DT.getRoots(); 1009 assert(Roots.size() == 1 && "Only one entry block for forward domfronts!"); 1010 calculate(DT, DT[Roots[0]]); 1011 return false; 1012 } 1013 1014 virtual void verifyAnalysis() const; 1015 1016 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 1017 AU.setPreservesAll(); 1018 AU.addRequired<DominatorTree>(); 1019 } 1020 1021 /// splitBlock - BB is split and now it has one successor. Update dominance 1022 /// frontier to reflect this change. 1023 void splitBlock(BasicBlock *BB); 1024 1025 /// BasicBlock BB's new dominator is NewBB. Update BB's dominance frontier 1026 /// to reflect this change. 1027 void changeImmediateDominator(BasicBlock *BB, BasicBlock *NewBB, 1028 DominatorTree *DT) { 1029 // NewBB is now dominating BB. Which means BB's dominance 1030 // frontier is now part of NewBB's dominance frontier. However, BB 1031 // itself is not member of NewBB's dominance frontier. 1032 DominanceFrontier::iterator NewDFI = find(NewBB); 1033 DominanceFrontier::iterator DFI = find(BB); 1034 // If BB was an entry block then its frontier is empty. 1035 if (DFI == end()) 1036 return; 1037 DominanceFrontier::DomSetType BBSet = DFI->second; 1038 for (DominanceFrontier::DomSetType::iterator BBSetI = BBSet.begin(), 1039 BBSetE = BBSet.end(); BBSetI != BBSetE; ++BBSetI) { 1040 BasicBlock *DFMember = *BBSetI; 1041 // Insert only if NewBB dominates DFMember. 1042 if (!DT->dominates(NewBB, DFMember)) 1043 NewDFI->second.insert(DFMember); 1044 } 1045 NewDFI->second.erase(BB); 1046 } 1047 1048 const DomSetType &calculate(const DominatorTree &DT, 1049 const DomTreeNode *Node); 1050}; 1051 1052 1053} // End llvm namespace 1054 1055#endif 1056