//
// 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.
//
//===----------------------------------------------------------------------===//
//
//===----------------------------------------------------------------------===//
#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<PostDominatorTree>
-F("postdomtree", "Post-Dominator Tree Construction", true);
-
-unsigned PostDominatorTree::DFSPass(BasicBlock *V, unsigned N) {
- std::vector<BasicBlock *> workStack;
- SmallPtrSet<BasicBlock *, 32> 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<UnreachableInst>(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<BasicBlock*> &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<BasicBlock*>().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<BasicBlock*> I = idf_begin(Roots[i]),
- E = idf_end(Roots[i]); I != E; ++I) {
- 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
-//===----------------------------------------------------------------------===//
-
-static RegisterPass<PostDominanceFrontier>
-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)
projects / oota-llvm.git / blobdiff