1 //===- llvm/Analysis/DominanceFrontier.h - Dominator Frontiers --*- 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 is the generic implementation of the DominanceFrontier class, which
11 // calculate and holds the dominance frontier for a function for.
13 // This should be considered deprecated, don't add any more uses of this data
16 //===----------------------------------------------------------------------===//
18 #ifndef LLVM_ANALYSIS_DOMINANCEFRONTIERIMPL_H
19 #define LLVM_ANALYSIS_DOMINANCEFRONTIERIMPL_H
21 #include "llvm/ADT/GraphTraits.h"
22 #include "llvm/ADT/SmallPtrSet.h"
23 #include "llvm/Analysis/DominanceFrontier.h"
24 #include "llvm/Support/Debug.h"
25 #include "llvm/Support/GenericDomTree.h"
26 #include "llvm/Support/raw_ostream.h"
34 template <class BlockT>
35 class DFCalculateWorkObject {
37 using DomTreeNodeT = DomTreeNodeBase<BlockT>;
39 DFCalculateWorkObject(BlockT *B, BlockT *P, const DomTreeNodeT *N,
40 const DomTreeNodeT *PN)
41 : currentBB(B), parentBB(P), Node(N), parentNode(PN) {}
45 const DomTreeNodeT *Node;
46 const DomTreeNodeT *parentNode;
49 template <class BlockT, bool IsPostDom>
50 void DominanceFrontierBase<BlockT, IsPostDom>::removeBlock(BlockT *BB) {
51 assert(find(BB) != end() && "Block is not in DominanceFrontier!");
52 for (iterator I = begin(), E = end(); I != E; ++I)
57 template <class BlockT, bool IsPostDom>
58 void DominanceFrontierBase<BlockT, IsPostDom>::addToFrontier(iterator I,
60 assert(I != end() && "BB is not in DominanceFrontier!");
61 assert(I->second.count(Node) && "Node is not in DominanceFrontier of BB");
62 I->second.erase(Node);
65 template <class BlockT, bool IsPostDom>
66 void DominanceFrontierBase<BlockT, IsPostDom>::removeFromFrontier(
67 iterator I, BlockT *Node) {
68 assert(I != end() && "BB is not in DominanceFrontier!");
69 assert(I->second.count(Node) && "Node is not in DominanceFrontier of BB");
70 I->second.erase(Node);
73 template <class BlockT, bool IsPostDom>
74 bool DominanceFrontierBase<BlockT, IsPostDom>::compareDomSet(
75 DomSetType &DS1, const DomSetType &DS2) const {
76 std::set<BlockT *> tmpSet;
77 for (BlockT *BB : DS2)
80 for (typename DomSetType::const_iterator I = DS1.begin(), E = DS1.end();
84 if (tmpSet.erase(Node) == 0)
85 // Node is in DS1 but tnot in DS2.
89 if (!tmpSet.empty()) {
90 // There are nodes that are in DS2 but not in DS1.
94 // DS1 and DS2 matches.
98 template <class BlockT, bool IsPostDom>
99 bool DominanceFrontierBase<BlockT, IsPostDom>::compare(
100 DominanceFrontierBase<BlockT, IsPostDom> &Other) const {
101 DomSetMapType tmpFrontiers;
102 for (typename DomSetMapType::const_iterator I = Other.begin(),
105 tmpFrontiers.insert(std::make_pair(I->first, I->second));
107 for (typename DomSetMapType::iterator I = tmpFrontiers.begin(),
108 E = tmpFrontiers.end();
110 BlockT *Node = I->first;
111 const_iterator DFI = find(Node);
115 if (compareDomSet(I->second, DFI->second))
119 tmpFrontiers.erase(Node);
122 if (!tmpFrontiers.empty())
128 template <class BlockT, bool IsPostDom>
129 void DominanceFrontierBase<BlockT, IsPostDom>::print(raw_ostream &OS) const {
130 for (const_iterator I = begin(), E = end(); I != E; ++I) {
131 OS << " DomFrontier for BB ";
133 I->first->printAsOperand(OS, false);
135 OS << " <<exit node>>";
138 const std::set<BlockT *> &BBs = I->second;
140 for (const BlockT *BB : BBs) {
143 BB->printAsOperand(OS, false);
145 OS << "<<exit node>>";
151 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
152 template <class BlockT, bool IsPostDom>
153 void DominanceFrontierBase<BlockT, IsPostDom>::dump() const {
158 template <class BlockT>
159 const typename ForwardDominanceFrontierBase<BlockT>::DomSetType &
160 ForwardDominanceFrontierBase<BlockT>::calculate(const DomTreeT &DT,
161 const DomTreeNodeT *Node) {
162 BlockT *BB = Node->getBlock();
163 DomSetType *Result = nullptr;
165 std::vector<DFCalculateWorkObject<BlockT>> workList;
166 SmallPtrSet<BlockT *, 32> visited;
168 workList.push_back(DFCalculateWorkObject<BlockT>(BB, nullptr, Node, nullptr));
170 DFCalculateWorkObject<BlockT> *currentW = &workList.back();
171 assert(currentW && "Missing work object.");
173 BlockT *currentBB = currentW->currentBB;
174 BlockT *parentBB = currentW->parentBB;
175 const DomTreeNodeT *currentNode = currentW->Node;
176 const DomTreeNodeT *parentNode = currentW->parentNode;
177 assert(currentBB && "Invalid work object. Missing current Basic Block");
178 assert(currentNode && "Invalid work object. Missing current Node");
179 DomSetType &S = this->Frontiers[currentBB];
181 // Visit each block only once.
182 if (visited.insert(currentBB).second) {
183 // Loop over CFG successors to calculate DFlocal[currentNode]
184 for (const auto Succ : children<BlockT *>(currentBB)) {
185 // Does Node immediately dominate this successor?
186 if (DT[Succ]->getIDom() != currentNode)
191 // At this point, S is DFlocal. Now we union in DFup's of our children...
192 // Loop through and visit the nodes that Node immediately dominates (Node's
193 // children in the IDomTree)
194 bool visitChild = false;
195 for (typename DomTreeNodeT::const_iterator NI = currentNode->begin(),
196 NE = currentNode->end();
198 DomTreeNodeT *IDominee = *NI;
199 BlockT *childBB = IDominee->getBlock();
200 if (visited.count(childBB) == 0) {
201 workList.push_back(DFCalculateWorkObject<BlockT>(
202 childBB, currentBB, IDominee, currentNode));
207 // If all children are visited or there is any child then pop this block
208 // from the workList.
215 typename DomSetType::const_iterator CDFI = S.begin(), CDFE = S.end();
216 DomSetType &parentSet = this->Frontiers[parentBB];
217 for (; CDFI != CDFE; ++CDFI) {
218 if (!DT.properlyDominates(parentNode, DT[*CDFI]))
219 parentSet.insert(*CDFI);
224 } while (!workList.empty());
229 } // end namespace llvm
231 #endif // LLVM_ANALYSIS_DOMINANCEFRONTIERIMPL_H