X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FAnalysis%2FPostDominators.cpp;h=6d929091e3d2ab4824cd0f0e3993595339386ae9;hp=69e9cbe26b8a405b262da5ec5f0cbec5b035f4a7;hb=609d95290a4d913139ba0b46f5b5b982dc4b1d96;hpb=3e089ae0b8aa6d9daf0b8ca8f6059422c45936f0 diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp index 69e9cbe26b8..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. // //===----------------------------------------------------------------------===// // @@ -12,250 +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" + //===----------------------------------------------------------------------===// // PostDominatorTree Implementation //===----------------------------------------------------------------------===// char PostDominatorTree::ID = 0; -char PostDominanceFrontier::ID = 0; -static RegisterPass -F("postdomtree", "Post-Dominator Tree Construction", true); - -unsigned PostDominatorTree::DFSPass(BasicBlock *V, unsigned N) { - std::vector workStack; - SmallPtrSet Visited; - workStack.push_back(V); - - do { - 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 - } - - // Visit children - bool visitChild = false; - for (pred_iterator PI = pred_begin(currentBB), PE = pred_end(currentBB); - PI != PE && !visitChild; ++PI) { - InfoRec &SuccVInfo = Info[*PI]; - if (SuccVInfo.Semi == 0) { - 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()); +INITIALIZE_PASS(PostDominatorTree, "postdomtree", + "Post-Dominator Tree Construction", true, true) - return N; +bool PostDominatorTree::runOnFunction(Function &F) { + DT->recalculate(F); + return false; } -void PostDominatorTree::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; +PostDominatorTree::~PostDominatorTree() { + delete DT; } -BasicBlock *PostDominatorTree::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 PostDominatorTree::Link(BasicBlock *V, BasicBlock *W, - InfoRec &WInfo) { - // Higher-complexity but faster implementation - WInfo.Ancestor = V; +void PostDominatorTree::print(raw_ostream &OS, const Module *) const { + DT->print(OS); } -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) { - 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); - - // 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], 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]; - } - - 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; - DomTreeNodes[Root] = RootNode = new DomTreeNode(Root, 0); - - // 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 = 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 - DomTreeNode *IPDomNode = getNodeForBlock(ImmPostDom); - - // Add a new tree node for this BasicBlock, and link it as a child of - // IDomNode - DomTreeNode *C = new DomTreeNode(I, IPDomNode); - DomTreeNodes[I] = C; - BBNode = IPDomNode->addChild(C); - } - } - - // Free temporary memory used to construct idom's - IDoms.clear(); - Info.clear(); - std::vector().swap(Vertex); - - // Start out with the DFS numbers being invalid. Let them be computed if - // demanded. - DFSInfoValid = false; -} - - -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); - return DomTreeNodes[BB] = IPDomNode->addChild(C); -} - -//===----------------------------------------------------------------------===// -// PostDominanceFrontier Implementation -//===----------------------------------------------------------------------===// - -static RegisterPass -H("postdomfrontier", "Post-Dominance Frontier Construction", true); - -const DominanceFrontier::DomSetType & -PostDominanceFrontier::calculate(const PostDominatorTree &DT, - 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... - 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? - 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 (DomTreeNode::const_iterator - NI = Node->begin(), NE = Node->end(); NI != NE; ++NI) { - DomTreeNode *IDominee = *NI; - const DomSetType &ChildDF = calculate(DT, IDominee); - - DomSetType::const_iterator CDFI = ChildDF.begin(), CDFE = ChildDF.end(); - for (; CDFI != CDFE; ++CDFI) { - if (!DT.properlyDominates(Node, 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)