X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FPostDominators.cpp;h=6d929091e3d2ab4824cd0f0e3993595339386ae9;hb=4d0731f50589c740744edcbc8af5250988c3e0ef;hp=381b03c71418187606c930c705a7afe78eef1790;hpb=dedf2bd5a34dac25e4245f58bb902ced6b64edd9;p=oota-llvm.git diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp index 381b03c7141..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. // //===----------------------------------------------------------------------===// // @@ -12,242 +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 "llvm/IR/CFG.h" +#include "llvm/IR/Instructions.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/GenericDomTreeConstruction.h" using namespace llvm; +#define DEBUG_TYPE "postdomtree" + //===----------------------------------------------------------------------===// -// PostDominatorSet Implementation +// PostDominatorTree Implementation //===----------------------------------------------------------------------===// -static RegisterAnalysis -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) { - Doms.clear(); // Reset from the last time we were run... - - // 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) { - Doms[I]; // Initialize to empty - - 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. - 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); - - bool Changed; - do { - Changed = false; - - std::set Visited; - DomSetType WorkingSet; +char PostDominatorTree::ID = 0; +INITIALIZE_PASS(PostDominatorTree, "postdomtree", + "Post-Dominator Tree Construction", true, true) - for (unsigned i = 0, e = Roots.size(); i != e; ++i) - for (idf_ext_iterator It = idf_ext_begin(Roots[i], Visited), - E = idf_ext_end(Roots[i], Visited); It != E; ++It) { - BasicBlock *BB = *It; - succ_iterator SI = succ_begin(BB), SE = succ_end(BB); - if (SI != SE) { // Is there SOME successor? - // Loop until we get to a successor that has had it's dom set filled - // in at least once. We are guaranteed to have this because we are - // traversing the graph in DFO and have handled start nodes specially. - // - while (Doms[*SI].size() == 0) ++SI; - WorkingSet = Doms[*SI]; - - for (++SI; SI != SE; ++SI) { // Intersect all of the successor sets - DomSetType &SuccSet = Doms[*SI]; - if (SuccSet.size()) - set_intersect(WorkingSet, SuccSet); - } - } else { - // If this node has no successors, it must be one of the root nodes. - // We will already take care of the notion that the node - // post-dominates itself. The only thing we have to add is that if - // there are multiple root nodes, we want to insert a special "null" - // exit node which dominates the roots as well. - if (Roots.size() > 1) - WorkingSet.insert(0); - } - - WorkingSet.insert(BB); // A block always dominates itself - DomSetType &BBSet = Doms[BB]; - if (BBSet != WorkingSet) { - BBSet.swap(WorkingSet); // Constant time operation! - Changed = true; // The sets changed. - } - WorkingSet.clear(); // Clear out the set for next iteration - } - } while (Changed); +bool PostDominatorTree::runOnFunction(Function &F) { + DT->recalculate(F); return false; } -//===----------------------------------------------------------------------===// -// ImmediatePostDominators Implementation -//===----------------------------------------------------------------------===// - -static RegisterAnalysis -D("postidom", "Immediate Post-Dominators Construction", true); - - -// calcIDoms - Calculate the immediate dominator mapping, given a set of -// dominators for every basic block. -void ImmediatePostDominators::calcIDoms(const DominatorSetBase &DS) { - // Loop over all of the nodes that have dominators... figuring out the IDOM - // for each node... - // - for (DominatorSet::const_iterator DI = DS.begin(), DEnd = DS.end(); - DI != DEnd; ++DI) { - BasicBlock *BB = DI->first; - const DominatorSet::DomSetType &Dominators = DI->second; - unsigned DomSetSize = Dominators.size(); - if (DomSetSize == 1) continue; // Root node... IDom = null - - // Loop over all dominators of this node. This corresponds to looping over - // nodes in the dominator chain, looking for a node whose dominator set is - // equal to the current nodes, except that the current node does not exist - // in it. This means that it is one level higher in the dom chain than the - // current node, and it is our idom! - // - DominatorSet::DomSetType::const_iterator I = Dominators.begin(); - DominatorSet::DomSetType::const_iterator End = Dominators.end(); - for (; I != End; ++I) { // Iterate over dominators... - // All of our dominators should form a chain, where the number of elements - // in the dominator set indicates what level the node is at in the chain. - // We want the node immediately above us, so it will have an identical - // dominator set, except that BB will not dominate it... therefore it's - // dominator set size will be one less than BB's... - // - if (DS.getDominators(*I).size() == DomSetSize - 1) { - IDoms[BB] = *I; - break; - } - } - } +PostDominatorTree::~PostDominatorTree() { + delete DT; } -//===----------------------------------------------------------------------===// -// PostDominatorTree Implementation -//===----------------------------------------------------------------------===// - -static RegisterAnalysis -F("postdomtree", "Post-Dominator Tree Construction", true); - -void PostDominatorTree::calculate(const PostDominatorSet &DS) { - if (Roots.empty()) return; - BasicBlock *Root = Roots.size() == 1 ? Roots[0] : 0; - - Nodes[Root] = RootNode = new Node(Root, 0); // Add a node for the root... - - // 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) { - BasicBlock *BB = *I; - const DominatorSet::DomSetType &Dominators = DS.getDominators(BB); - unsigned DomSetSize = Dominators.size(); - if (DomSetSize == 1) continue; // Root node... IDom = null - - // If we have already computed the immediate dominator for this node, - // don't revisit. This can happen due to nodes reachable from multiple - // roots, but which the idf_iterator doesn't know about. - if (Nodes.find(BB) != Nodes.end()) continue; - - // Loop over all dominators of this node. This corresponds to looping - // over nodes in the dominator chain, looking for a node whose dominator - // set is equal to the current nodes, except that the current node does - // not exist in it. This means that it is one level higher in the dom - // chain than the current node, and it is our idom! We know that we have - // already added a DominatorTree node for our idom, because the idom must - // be a predecessor in the depth first order that we are iterating through - // the function. - // - for (DominatorSet::DomSetType::const_iterator I = Dominators.begin(), - E = Dominators.end(); I != E; ++I) { // Iterate over dominators. - // All of our dominators should form a chain, where the number - // of elements in the dominator set indicates what level the - // node is at in the chain. We want the node immediately - // above us, so it will have an identical dominator set, - // except that BB will not dominate it... therefore it's - // dominator set size will be one less than BB's... - // - if (DS.getDominators(*I).size() == DomSetSize - 1) { - // We know that the immediate dominator should already have a node, - // because we are traversing the CFG in depth first order! - // - Node *IDomNode = Nodes[*I]; - assert(IDomNode && "No node for IDOM?"); - - // Add a new tree node for this BasicBlock, and link it as a child of - // IDomNode - Nodes[BB] = IDomNode->addChild(new Node(BB, IDomNode)); - break; - } - } - } +void PostDominatorTree::print(raw_ostream &OS, const Module *) const { + DT->print(OS); } -//===----------------------------------------------------------------------===// -// PostDominanceFrontier Implementation -//===----------------------------------------------------------------------===// - -static RegisterAnalysis -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->dominates(DT[*CDFI])) - S.insert(*CDFI); - } - } - - return S; -} -// stub - a dummy function to make linking work ok. -void PostDominanceFrontier::stub() { +FunctionPass* llvm::createPostDomTree() { + return new PostDominatorTree(); }