X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FAnalysis%2FPostDominators.cpp;h=6d929091e3d2ab4824cd0f0e3993595339386ae9;hp=8b66ff6cad12f38cb872aadc465e432c97e9c61e;hb=b4401e33d533275568edc5e479b43c0a8e64c6f9;hpb=a69fd903585a665c031d5aa3fdfb8dc919b44bef diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp index 8b66ff6cad1..6d929091e3d 100644 --- a/lib/Analysis/PostDominators.cpp +++ b/lib/Analysis/PostDominators.cpp @@ -1,189 +1,50 @@ //===- PostDominators.cpp - Post-Dominator Calculation --------------------===// // +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// // This file implements the post-dominator construction algorithms. // //===----------------------------------------------------------------------===// #include "llvm/Analysis/PostDominators.h" -#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h" -#include "llvm/Support/CFG.h" -#include "Support/DepthFirstIterator.h" -#include "Support/SetOperations.h" -using std::set; +#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... - // Since we require that the unify all exit nodes pass has been run, we know - // that there can be at most one return instruction in the function left. - // Get it. - // - Root = getAnalysis().getExitNode(); +char PostDominatorTree::ID = 0; +INITIALIZE_PASS(PostDominatorTree, "postdomtree", + "Post-Dominator Tree Construction", true, true) - if (Root == 0) { // No exit node for the function? Postdomsets are all empty - for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) - Doms[FI] = DomSetType(); - return false; - } - - bool Changed; - do { - Changed = false; - - set Visited; - DomSetType WorkingSet; - idf_iterator It = idf_begin(Root), End = idf_end(Root); - for ( ; It != End; ++It) { - BasicBlock *BB = *It; - succ_iterator PI = succ_begin(BB), PEnd = succ_end(BB); - if (PI != PEnd) { // Is there SOME predecessor? - // 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[*PI].size() == 0) ++PI; - WorkingSet = Doms[*PI]; - - for (++PI; PI != PEnd; ++PI) { // Intersect all of the successor sets - DomSetType &PredSet = Doms[*PI]; - if (PredSet.size()) - set_intersect(WorkingSet, PredSet); - } - } - - 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; } -// getAnalysisUsage - This obviously provides a post-dominator set, but it also -// requires the UnifyFunctionExitNodes pass. -// -void PostDominatorSet::getAnalysisUsage(AnalysisUsage &AU) const { - AU.setPreservesAll(); - AU.addRequired(); +PostDominatorTree::~PostDominatorTree() { + delete DT; } -//===----------------------------------------------------------------------===// -// ImmediatePostDominators Implementation -//===----------------------------------------------------------------------===// - -static RegisterAnalysis -D("postidom", "Immediate Post-Dominators Construction", true); - -//===----------------------------------------------------------------------===// -// PostDominatorTree Implementation -//===----------------------------------------------------------------------===// - -static RegisterAnalysis -F("postdomtree", "Post-Dominator Tree Construction", true); - -void PostDominatorTree::calculate(const PostDominatorSet &DS) { - Nodes[Root] = new Node(Root, 0); // Add a node for the root... - - if (Root) { - // Iterate over all nodes in depth first order... - for (idf_iterator I = idf_begin(Root), E = idf_end(Root); - 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 - - // 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. - // - 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) { - // 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->getNode(); - DomSetType &S = Frontiers[BB]; // The new set to fill in... - if (!Root) return S; - - for (pred_iterator SI = pred_begin(BB), SE = pred_end(BB); - SI != SE; ++SI) { - // Does Node immediately dominate this predeccessor? - 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; +FunctionPass* llvm::createPostDomTree() { + return new PostDominatorTree(); } -// stub - a dummy function to make linking work ok. -void PostDominanceFrontier::stub() { -}