1//===- llvm/Analysis/DominanceFrontier.h - Dominator Frontiers --*- 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 is the generic implementation of the DominanceFrontier class, which 11// calculate and holds the dominance frontier for a function for. 12// 13// This should be considered deprecated, don't add any more uses of this data 14// structure. 15// 16//===----------------------------------------------------------------------===// 17 18#ifndef LLVM_ANALYSIS_DOMINANCEFRONTIERIMPL_H 19#define LLVM_ANALYSIS_DOMINANCEFRONTIERIMPL_H 20 21#include "llvm/ADT/SmallPtrSet.h" 22#include "llvm/Analysis/DominanceFrontier.h" 23#include "llvm/Support/Debug.h" 24#include "llvm/Support/GenericDomTree.h" 25 26namespace llvm { 27 28template <class BlockT> 29class DFCalculateWorkObject { 30public: 31 typedef DomTreeNodeBase<BlockT> DomTreeNodeT; 32 33 DFCalculateWorkObject(BlockT *B, BlockT *P, const DomTreeNodeT *N, 34 const DomTreeNodeT *PN) 35 : currentBB(B), parentBB(P), Node(N), parentNode(PN) {} 36 BlockT *currentBB; 37 BlockT *parentBB; 38 const DomTreeNodeT *Node; 39 const DomTreeNodeT *parentNode; 40}; 41 42template <class BlockT> 43void DominanceFrontierBase<BlockT>::removeBlock(BlockT *BB) { 44 assert(find(BB) != end() && "Block is not in DominanceFrontier!"); 45 for (iterator I = begin(), E = end(); I != E; ++I) 46 I->second.erase(BB); 47 Frontiers.erase(BB); 48} 49 50template <class BlockT> 51void DominanceFrontierBase<BlockT>::addToFrontier(iterator I, 52 BlockT *Node) { 53 assert(I != end() && "BB is not in DominanceFrontier!"); 54 assert(I->second.count(Node) && "Node is not in DominanceFrontier of BB"); 55 I->second.erase(Node); 56} 57 58template <class BlockT> 59void DominanceFrontierBase<BlockT>::removeFromFrontier(iterator I, 60 BlockT *Node) { 61 assert(I != end() && "BB is not in DominanceFrontier!"); 62 assert(I->second.count(Node) && "Node is not in DominanceFrontier of BB"); 63 I->second.erase(Node); 64} 65 66template <class BlockT> 67bool DominanceFrontierBase<BlockT>::compareDomSet(DomSetType &DS1, 68 const DomSetType &DS2) const { 69 std::set<BlockT *> tmpSet; 70 for (BlockT *BB : DS2) 71 tmpSet.insert(BB); 72 73 for (typename DomSetType::const_iterator I = DS1.begin(), E = DS1.end(); 74 I != E;) { 75 BlockT *Node = *I++; 76 77 if (tmpSet.erase(Node) == 0) 78 // Node is in DS1 but tnot in DS2. 79 return true; 80 } 81 82 if (!tmpSet.empty()) { 83 // There are nodes that are in DS2 but not in DS1. 84 return true; 85 } 86 87 // DS1 and DS2 matches. 88 return false; 89} 90 91template <class BlockT> 92bool DominanceFrontierBase<BlockT>::compare( 93 DominanceFrontierBase<BlockT> &Other) const { 94 DomSetMapType tmpFrontiers; 95 for (typename DomSetMapType::const_iterator I = Other.begin(), 96 E = Other.end(); 97 I != E; ++I) 98 tmpFrontiers.insert(std::make_pair(I->first, I->second)); 99 100 for (typename DomSetMapType::iterator I = tmpFrontiers.begin(), 101 E = tmpFrontiers.end(); 102 I != E;) { 103 BlockT *Node = I->first; 104 const_iterator DFI = find(Node); 105 if (DFI == end()) 106 return true; 107 108 if (compareDomSet(I->second, DFI->second)) 109 return true; 110 111 ++I; 112 tmpFrontiers.erase(Node); 113 } 114 115 if (!tmpFrontiers.empty()) 116 return true; 117 118 return false; 119} 120 121template <class BlockT> 122void DominanceFrontierBase<BlockT>::print(raw_ostream &OS) const { 123 for (const_iterator I = begin(), E = end(); I != E; ++I) { 124 OS << " DomFrontier for BB "; 125 if (I->first) 126 I->first->printAsOperand(OS, false); 127 else 128 OS << " <<exit node>>"; 129 OS << " is:\t"; 130 131 const std::set<BlockT *> &BBs = I->second; 132 133 for (const BlockT *BB : BBs) { 134 OS << ' '; 135 if (BB) 136 BB->printAsOperand(OS, false); 137 else 138 OS << "<<exit node>>"; 139 } 140 OS << '\n'; 141 } 142} 143 144#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 145template <class BlockT> 146void DominanceFrontierBase<BlockT>::dump() const { 147 print(dbgs()); 148} 149#endif 150 151template <class BlockT> 152const typename ForwardDominanceFrontierBase<BlockT>::DomSetType & 153ForwardDominanceFrontierBase<BlockT>::calculate(const DomTreeT &DT, 154 const DomTreeNodeT *Node) { 155 BlockT *BB = Node->getBlock(); 156 DomSetType *Result = nullptr; 157 158 std::vector<DFCalculateWorkObject<BlockT>> workList; 159 SmallPtrSet<BlockT *, 32> visited; 160 161 workList.push_back(DFCalculateWorkObject<BlockT>(BB, nullptr, Node, nullptr)); 162 do { 163 DFCalculateWorkObject<BlockT> *currentW = &workList.back(); 164 assert(currentW && "Missing work object."); 165 166 BlockT *currentBB = currentW->currentBB; 167 BlockT *parentBB = currentW->parentBB; 168 const DomTreeNodeT *currentNode = currentW->Node; 169 const DomTreeNodeT *parentNode = currentW->parentNode; 170 assert(currentBB && "Invalid work object. Missing current Basic Block"); 171 assert(currentNode && "Invalid work object. Missing current Node"); 172 DomSetType &S = this->Frontiers[currentBB]; 173 174 // Visit each block only once. 175 if (visited.insert(currentBB).second) { 176 // Loop over CFG successors to calculate DFlocal[currentNode] 177 for (const auto Succ : children<BlockT *>(currentBB)) { 178 // Does Node immediately dominate this successor? 179 if (DT[Succ]->getIDom() != currentNode) 180 S.insert(Succ); 181 } 182 } 183 184 // At this point, S is DFlocal. Now we union in DFup's of our children... 185 // Loop through and visit the nodes that Node immediately dominates (Node's 186 // children in the IDomTree) 187 bool visitChild = false; 188 for (typename DomTreeNodeT::const_iterator NI = currentNode->begin(), 189 NE = currentNode->end(); 190 NI != NE; ++NI) { 191 DomTreeNodeT *IDominee = *NI; 192 BlockT *childBB = IDominee->getBlock(); 193 if (visited.count(childBB) == 0) { 194 workList.push_back(DFCalculateWorkObject<BlockT>( 195 childBB, currentBB, IDominee, currentNode)); 196 visitChild = true; 197 } 198 } 199 200 // If all children are visited or there is any child then pop this block 201 // from the workList. 202 if (!visitChild) { 203 if (!parentBB) { 204 Result = &S; 205 break; 206 } 207 208 typename DomSetType::const_iterator CDFI = S.begin(), CDFE = S.end(); 209 DomSetType &parentSet = this->Frontiers[parentBB]; 210 for (; CDFI != CDFE; ++CDFI) { 211 if (!DT.properlyDominates(parentNode, DT[*CDFI])) 212 parentSet.insert(*CDFI); 213 } 214 workList.pop_back(); 215 } 216 217 } while (!workList.empty()); 218 219 return *Result; 220} 221 222} // End llvm namespace 223 224#endif 225