X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FPostDominators.cpp;h=6d929091e3d2ab4824cd0f0e3993595339386ae9;hb=099e59a6c1ef06c78b32173f2083f4fddcb329f4;hp=bfa152035e0f57d50ce6b875bfb4e84d530ddc79;hpb=f93f68347f06f6e12dd214c21436bfde55e66bf7;p=oota-llvm.git diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp index bfa152035e0..6d929091e3d 100644 --- a/lib/Analysis/PostDominators.cpp +++ b/lib/Analysis/PostDominators.cpp @@ -2,8 +2,8 @@ // // The LLVM Compiler Infrastructure // -// This file was developed by the LLVM research group and is distributed under -// the University of Illinois Open Source License. See LICENSE.TXT for details. +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // @@ -12,365 +12,39 @@ //===----------------------------------------------------------------------===// #include "llvm/Analysis/PostDominators.h" -#include "llvm/Instructions.h" -#include "llvm/Support/CFG.h" #include "llvm/ADT/DepthFirstIterator.h" #include "llvm/ADT/SetOperations.h" -#include +#include "llvm/IR/CFG.h" +#include "llvm/IR/Instructions.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/GenericDomTreeConstruction.h" using namespace llvm; -//===----------------------------------------------------------------------===// -// ImmediatePostDominators Implementation -//===----------------------------------------------------------------------===// - -static RegisterPass -D("postidom", "Immediate Post-Dominators Construction", true); - -unsigned ImmediatePostDominators::DFSPass(BasicBlock *V, InfoRec &VInfo, - unsigned N) { - - std::vector > workStack; - workStack.push_back(std::make_pair(V, &VInfo)); - - 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 - - // For PostDominators, we want to walk predecessors rather than successors - // as we do in forward Dominators. - for (pred_iterator PI = pred_begin(currentBB), PE = pred_end(currentBB); - PI != PE; ++PI) { - InfoRec &SuccVInfo = Info[*PI]; - if (SuccVInfo.Semi == 0) { - SuccVInfo.Parent = currentBB; - - workStack.push_back(std::make_pair(*PI, &SuccVInfo)); - } - } - } while (!workStack.empty()); - return N; -} - -void ImmediatePostDominators::Compress(BasicBlock *V, InfoRec &VInfo) { - BasicBlock *VAncestor = VInfo.Ancestor; - InfoRec &VAInfo = Info[VAncestor]; - if (VAInfo.Ancestor == 0) - return; - - Compress(VAncestor, VAInfo); - - BasicBlock *VAncestorLabel = VAInfo.Label; - BasicBlock *VLabel = VInfo.Label; - if (Info[VAncestorLabel].Semi < Info[VLabel].Semi) - VInfo.Label = VAncestorLabel; - - VInfo.Ancestor = VAInfo.Ancestor; -} - -BasicBlock *ImmediatePostDominators::Eval(BasicBlock *V) { - InfoRec &VInfo = Info[V]; - - // Higher-complexity but faster implementation - if (VInfo.Ancestor == 0) - return V; - Compress(V, VInfo); - return VInfo.Label; -} - -void ImmediatePostDominators::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(); - - // 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); - - Vertex.push_back(0); - - // Step #1: Number blocks in depth-first order and initialize variables used - // 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); - - for (unsigned i = N; i >= 2; --i) { - BasicBlock *W = Vertex[i]; - InfoRec &WInfo = Info[W]; - - // Step #2: Calculate the semidominators of all vertices - for (succ_iterator SI = succ_begin(W), SE = succ_end(W); SI != SE; ++SI) - if (Info.count(*SI)) { // Only if this predecessor is reachable! - unsigned SemiU = Info[Eval(*SI)].Semi; - if (SemiU < WInfo.Semi) - WInfo.Semi = SemiU; - } - - Info[Vertex[WInfo.Semi]].Bucket.push_back(W); - - BasicBlock *WParent = WInfo.Parent; - Link(WParent, W, WInfo); - - // Step #3: Implicitly define the immediate dominator of vertices - std::vector &WParentBucket = Info[WParent].Bucket; - while (!WParentBucket.empty()) { - BasicBlock *V = WParentBucket.back(); - WParentBucket.pop_back(); - BasicBlock *U = Eval(V); - IDoms[V] = Info[U].Semi < Info[V].Semi ? U : WParent; - } - } - - // Step #4: Explicitly define the immediate dominator of each vertex - for (unsigned i = 2; i <= N; ++i) { - BasicBlock *W = Vertex[i]; - BasicBlock *&WIDom = IDoms[W]; - if (WIDom != Vertex[Info[W].Semi]) - 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; -} +#define DEBUG_TYPE "postdomtree" //===----------------------------------------------------------------------===// // PostDominatorTree Implementation //===----------------------------------------------------------------------===// -static RegisterPass -F("postdomtree", "Post-Dominator Tree Construction", true); +char PostDominatorTree::ID = 0; +INITIALIZE_PASS(PostDominatorTree, "postdomtree", + "Post-Dominator Tree Construction", true, 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); - - 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]; - if (!BBNode) { // Haven't calculated this node yet? - // Get or calculate the node for the immediate dominator - Node *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)); - } - } +bool PostDominatorTree::runOnFunction(Function &F) { + DT->recalculate(F); + return false; } -//===----------------------------------------------------------------------===// -// 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; - } +PostDominatorTree::~PostDominatorTree() { + delete DT; } -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); - } - } - - 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); - } - DFSInfoValid = true; +void PostDominatorTree::print(raw_ostream &OS, const Module *) const { + DT->print(OS); } -//===----------------------------------------------------------------------===// -// PostDominanceFrontier Implementation -//===----------------------------------------------------------------------===// - -static RegisterPass -H("postdomfrontier", "Post-Dominance Frontier Construction", true); - -const DominanceFrontier::DomSetType & -PostDominanceFrontier::calculate(const PostDominatorTree &DT, - const DominatorTree::Node *Node) { - // Loop over CFG successors to calculate DFlocal[Node] - BasicBlock *BB = Node->getBlock(); - DomSetType &S = Frontiers[BB]; // The new set to fill in... - if (getRoots().empty()) return S; - - if (BB) - for (pred_iterator SI = pred_begin(BB), SE = pred_end(BB); - SI != SE; ++SI) - // Does Node immediately dominate this predecessor? - if (DT[*SI]->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 - NI = Node->begin(), NE = Node->end(); NI != NE; ++NI) { - DominatorTree::Node *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])) - S.insert(*CDFI); - } - } - return S; +FunctionPass* llvm::createPostDomTree() { + return new PostDominatorTree(); } -// Ensure that this .cpp file gets linked when PostDominators.h is used. -DEFINING_FILE_FOR(PostDominanceFrontier)