X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FPostDominators.cpp;h=d2892de8ed2429622a930271e3b959f9d1856389;hb=2f0d1ea864ff0fe59c5a2b35390a82fad2865b61;hp=b0b2374317dbd2716890fc2a8d570329ab2ba1aa;hpb=c8719e935397ee86cd8555771f0a40cc0496e8f2;p=oota-llvm.git diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp index b0b2374317d..d2892de8ed2 100644 --- a/lib/Analysis/PostDominators.cpp +++ b/lib/Analysis/PostDominators.cpp @@ -16,52 +16,63 @@ #include "llvm/Support/CFG.h" #include "llvm/ADT/DepthFirstIterator.h" #include "llvm/ADT/SetOperations.h" -#include using namespace llvm; //===----------------------------------------------------------------------===// -// ImmediatePostDominators Implementation +// PostDominatorTree Implementation //===----------------------------------------------------------------------===// -static RegisterPass -D("postidom", "Immediate Post-Dominators Construction", true); - -unsigned ImmediatePostDominators::DFSPass(BasicBlock *V, InfoRec &VInfo, - unsigned N) { +char PostDominatorTree::ID = 0; +char PostDominanceFrontier::ID = 0; +static RegisterPass +F("postdomtree", "Post-Dominator Tree Construction", true); - std::vector > workStack; - workStack.push_back(std::make_pair(V, &VInfo)); +unsigned PostDominatorTree::DFSPass(BasicBlock *V, unsigned N) { + std::vector workStack; + SmallPtrSet Visited; + workStack.push_back(V); do { - BasicBlock *currentBB = workStack.back().first; - InfoRec *currentVInfo = workStack.back().second; - workStack.pop_back(); - - currentVInfo->Semi = ++N; - currentVInfo->Label = currentBB; - - Vertex.push_back(currentBB); // Vertex[n] = current; - // Info[currentBB].Ancestor = 0; - // Ancestor[n] = 0 - // Child[currentBB] = 0; - currentVInfo->Size = 1; // Size[currentBB] = 1 + BasicBlock *currentBB = workStack.back(); + InfoRec &CurVInfo = Info[currentBB]; + + // Visit each block only once. + if (Visited.insert(currentBB)) { + CurVInfo.Semi = ++N; + CurVInfo.Label = currentBB; + + Vertex.push_back(currentBB); // Vertex[n] = current; + // Info[currentBB].Ancestor = 0; + // Ancestor[n] = 0 + // Child[currentBB] = 0; + CurVInfo.Size = 1; // Size[currentBB] = 1 + } - // For PostDominators, we want to walk predecessors rather than successors - // as we do in forward Dominators. + // Visit children + bool visitChild = false; for (pred_iterator PI = pred_begin(currentBB), PE = pred_end(currentBB); - PI != PE; ++PI) { + PI != PE && !visitChild; ++PI) { InfoRec &SuccVInfo = Info[*PI]; if (SuccVInfo.Semi == 0) { - SuccVInfo.Parent = currentBB; - - workStack.push_back(std::make_pair(*PI, &SuccVInfo)); + SuccVInfo.Parent = currentBB; + if (!Visited.count(*PI)) { + workStack.push_back(*PI); + visitChild = true; + } } } + + // If all children are visited or if this block has no child then pop this + // block out of workStack. + if (!visitChild) + workStack.pop_back(); + } while (!workStack.empty()); + return N; } -void ImmediatePostDominators::Compress(BasicBlock *V, InfoRec &VInfo) { +void PostDominatorTree::Compress(BasicBlock *V, InfoRec &VInfo) { BasicBlock *VAncestor = VInfo.Ancestor; InfoRec &VAInfo = Info[VAncestor]; if (VAInfo.Ancestor == 0) @@ -77,7 +88,7 @@ void ImmediatePostDominators::Compress(BasicBlock *V, InfoRec &VInfo) { VInfo.Ancestor = VAInfo.Ancestor; } -BasicBlock *ImmediatePostDominators::Eval(BasicBlock *V) { +BasicBlock *PostDominatorTree::Eval(BasicBlock *V) { InfoRec &VInfo = Info[V]; // Higher-complexity but faster implementation @@ -87,22 +98,28 @@ BasicBlock *ImmediatePostDominators::Eval(BasicBlock *V) { return VInfo.Label; } -void ImmediatePostDominators::Link(BasicBlock *V, BasicBlock *W, +void PostDominatorTree::Link(BasicBlock *V, BasicBlock *W, InfoRec &WInfo) { // Higher-complexity but faster implementation WInfo.Ancestor = V; } -bool ImmediatePostDominators::runOnFunction(Function &F) { - IDoms.clear(); // Reset from the last time we were run... - Roots.clear(); - +void PostDominatorTree::calculate(Function &F) { // Step #0: Scan the function looking for the root nodes of the post-dominance // relationships. These blocks, which have no successors, end with return and // unwind instructions. - for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) - if (succ_begin(I) == succ_end(I)) - Roots.push_back(I); + for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) { + TerminatorInst *Insn = I->getTerminator(); + if (Insn->getNumSuccessors() == 0) { + // Unreachable block is not a root node. + if (!isa(Insn)) + Roots.push_back(I); + } + + // Prepopulate maps so that we don't get iterator invalidation issues later. + IDoms[I] = 0; + DomTreeNodes[I] = 0; + } Vertex.push_back(0); @@ -110,7 +127,7 @@ bool ImmediatePostDominators::runOnFunction(Function &F) { // in later stages of the algorithm. unsigned N = 0; for (unsigned i = 0, e = Roots.size(); i != e; ++i) - N = DFSPass(Roots[i], Info[Roots[i]], N); + N = DFSPass(Roots[i], N); for (unsigned i = N; i >= 2; --i) { BasicBlock *W = Vertex[i]; @@ -147,190 +164,63 @@ bool ImmediatePostDominators::runOnFunction(Function &F) { WIDom = IDoms[WIDom]; } - // Free temporary memory used to construct idom's - Info.clear(); - std::vector().swap(Vertex); - - return false; -} - -//===----------------------------------------------------------------------===// -// PostDominatorSet Implementation -//===----------------------------------------------------------------------===// - -static RegisterPass -B("postdomset", "Post-Dominator Set Construction", true); - -// Postdominator set construction. This converts the specified function to only -// have a single exit node (return stmt), then calculates the post dominance -// sets for the function. -// -bool PostDominatorSet::runOnFunction(Function &F) { - // Scan the function looking for the root nodes of the post-dominance - // relationships. These blocks end with return and unwind instructions. - // While we are iterating over the function, we also initialize all of the - // domsets to empty. - Roots.clear(); - for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) - if (succ_begin(I) == succ_end(I)) - Roots.push_back(I); - - // If there are no exit nodes for the function, postdomsets are all empty. - // This can happen if the function just contains an infinite loop, for - // example. - ImmediatePostDominators &IPD = getAnalysis(); - Doms.clear(); // Reset from the last time we were run... - if (Roots.empty()) return false; - - // If we have more than one root, we insert an artificial "null" exit, which - // has "virtual edges" to each of the real exit nodes. - //if (Roots.size() > 1) - // Doms[0].insert(0); - - // Root nodes only dominate themselves. - for (unsigned i = 0, e = Roots.size(); i != e; ++i) - Doms[Roots[i]].insert(Roots[i]); - - // Loop over all of the blocks in the function, calculating dominator sets for - // each function. - for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) - if (BasicBlock *IPDom = IPD[I]) { // Get idom if block is reachable - DomSetType &DS = Doms[I]; - assert(DS.empty() && "PostDomset already filled in for this block?"); - DS.insert(I); // Blocks always dominate themselves - - // Insert all dominators into the set... - while (IPDom) { - // If we have already computed the dominator sets for our immediate post - // dominator, just use it instead of walking all the way up to the root. - DomSetType &IPDS = Doms[IPDom]; - if (!IPDS.empty()) { - DS.insert(IPDS.begin(), IPDS.end()); - break; - } else { - DS.insert(IPDom); - IPDom = IPD[IPDom]; - } - } - } else { - // Ensure that every basic block has at least an empty set of nodes. This - // is important for the case when there is unreachable blocks. - Doms[I]; - } - - return false; -} - -//===----------------------------------------------------------------------===// -// PostDominatorTree Implementation -//===----------------------------------------------------------------------===// - -static RegisterPass -F("postdomtree", "Post-Dominator Tree Construction", true); - -DominatorTreeBase::Node *PostDominatorTree::getNodeForBlock(BasicBlock *BB) { - Node *&BBNode = Nodes[BB]; - if (BBNode) return BBNode; - - // Haven't calculated this node yet? Get or calculate the node for the - // immediate postdominator. - BasicBlock *IPDom = getAnalysis()[BB]; - Node *IPDomNode = getNodeForBlock(IPDom); - - // Add a new tree node for this BasicBlock, and link it as a child of - // IDomNode - return BBNode = IPDomNode->addChild(new Node(BB, IPDomNode)); -} - -void PostDominatorTree::calculate(const ImmediatePostDominators &IPD) { if (Roots.empty()) return; // Add a node for the root. This node might be the actual root, if there is // one exit block, or it may be the virtual exit (denoted by (BasicBlock *)0) // which postdominates all real exits if there are multiple exit blocks. BasicBlock *Root = Roots.size() == 1 ? Roots[0] : 0; - Nodes[Root] = RootNode = new Node(Root, 0); + DomTreeNodes[Root] = RootNode = new DomTreeNode(Root, 0); - Function *F = Roots[0]->getParent(); // Loop over all of the reachable blocks in the function... - for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) - if (BasicBlock *ImmPostDom = IPD.get(I)) { // Reachable block. - Node *&BBNode = Nodes[I]; + for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) + if (BasicBlock *ImmPostDom = getIDom(I)) { // Reachable block. + DomTreeNode *&BBNode = DomTreeNodes[I]; if (!BBNode) { // Haven't calculated this node yet? // Get or calculate the node for the immediate dominator - Node *IPDomNode = getNodeForBlock(ImmPostDom); + DomTreeNode *IPDomNode = getNodeForBlock(ImmPostDom); // Add a new tree node for this BasicBlock, and link it as a child of // IDomNode - BBNode = IPDomNode->addChild(new Node(I, IPDomNode)); + DomTreeNode *C = new DomTreeNode(I, IPDomNode); + DomTreeNodes[I] = C; + BBNode = IPDomNode->addChild(C); } } -} - -//===----------------------------------------------------------------------===// -// PostETForest Implementation -//===----------------------------------------------------------------------===// - -static RegisterPass -G("postetforest", "Post-ET-Forest Construction", true); - -ETNode *PostETForest::getNodeForBlock(BasicBlock *BB) { - ETNode *&BBNode = Nodes[BB]; - if (BBNode) return BBNode; - - // Haven't calculated this node yet? Get or calculate the node for the - // immediate dominator. - BasicBlock *IDom = getAnalysis()[BB]; - - // If we are unreachable, we may not have an immediate dominator. - if (!IDom) - return BBNode = new ETNode(BB); - else { - ETNode *IDomNode = getNodeForBlock(IDom); - - // Add a new tree node for this BasicBlock, and link it as a child of - // IDomNode - BBNode = new ETNode(BB); - BBNode->setFather(IDomNode); - return BBNode; - } -} -void PostETForest::calculate(const ImmediatePostDominators &ID) { - for (unsigned i = 0, e = Roots.size(); i != e; ++i) - Nodes[Roots[i]] = new ETNode(Roots[i]); // Add a node for the root - - // Iterate over all nodes in inverse depth first order. - for (unsigned i = 0, e = Roots.size(); i != e; ++i) - for (idf_iterator I = idf_begin(Roots[i]), - E = idf_end(Roots[i]); I != E; ++I) { - BasicBlock *BB = *I; - ETNode *&BBNode = Nodes[BB]; - if (!BBNode) { - ETNode *IDomNode = NULL; - - if (ID.get(BB)) - IDomNode = getNodeForBlock(ID.get(BB)); - - // Add a new ETNode for this BasicBlock, and set it's parent - // to it's immediate dominator. - BBNode = new ETNode(BB); - if (IDomNode) - BBNode->setFather(IDomNode); - } - } + // Free temporary memory used to construct idom's + IDoms.clear(); + Info.clear(); + std::vector().swap(Vertex); int dfsnum = 0; // Iterate over all nodes in depth first order... for (unsigned i = 0, e = Roots.size(); i != e; ++i) for (idf_iterator I = idf_begin(Roots[i]), E = idf_end(Roots[i]); I != E; ++I) { - if (!getNodeForBlock(*I)->hasFather()) - getNodeForBlock(*I)->assignDFSNumber(dfsnum); + if (!getNodeForBlock(*I)->getIDom()) + getNodeForBlock(*I)->assignDFSNumber(dfsnum); } DFSInfoValid = true; } + +DomTreeNode *PostDominatorTree::getNodeForBlock(BasicBlock *BB) { + DomTreeNode *&BBNode = DomTreeNodes[BB]; + if (BBNode) return BBNode; + + // Haven't calculated this node yet? Get or calculate the node for the + // immediate postdominator. + BasicBlock *IPDom = getIDom(BB); + DomTreeNode *IPDomNode = getNodeForBlock(IPDom); + + // Add a new tree node for this BasicBlock, and link it as a child of + // IDomNode + DomTreeNode *C = new DomTreeNode(BB, IPDomNode); + DomTreeNodes[BB] = C; + return BBNode = IPDomNode->addChild(C); +} + //===----------------------------------------------------------------------===// // PostDominanceFrontier Implementation //===----------------------------------------------------------------------===// @@ -340,7 +230,7 @@ H("postdomfrontier", "Post-Dominance Frontier Construction", true); const DominanceFrontier::DomSetType & PostDominanceFrontier::calculate(const PostDominatorTree &DT, - const DominatorTree::Node *Node) { + const DomTreeNode *Node) { // Loop over CFG successors to calculate DFlocal[Node] BasicBlock *BB = Node->getBlock(); DomSetType &S = Frontiers[BB]; // The new set to fill in... @@ -348,23 +238,25 @@ PostDominanceFrontier::calculate(const PostDominatorTree &DT, if (BB) for (pred_iterator SI = pred_begin(BB), SE = pred_end(BB); - SI != SE; ++SI) + SI != SE; ++SI) { // Does Node immediately dominate this predecessor? - if (DT[*SI]->getIDom() != Node) + DomTreeNode *SINode = DT[*SI]; + if (SINode && SINode->getIDom() != Node) S.insert(*SI); + } // At this point, S is DFlocal. Now we union in DFup's of our children... // Loop through and visit the nodes that Node immediately dominates (Node's // children in the IDomTree) // - for (PostDominatorTree::Node::const_iterator + for (DomTreeNode::const_iterator NI = Node->begin(), NE = Node->end(); NI != NE; ++NI) { - DominatorTree::Node *IDominee = *NI; + DomTreeNode *IDominee = *NI; const DomSetType &ChildDF = calculate(DT, IDominee); DomSetType::const_iterator CDFI = ChildDF.begin(), CDFE = ChildDF.end(); for (; CDFI != CDFE; ++CDFI) { - if (!Node->properlyDominates(DT[*CDFI])) + if (!DT.properlyDominates(Node, DT[*CDFI])) S.insert(*CDFI); } }