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04fa569320
into a separate header file. Next step: merging PostDominatorCalculation.h with DominatorCalculation.h. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42251 91177308-0d34-0410-b5e6-96231b3b80d8
121 lines
4.0 KiB
C++
121 lines
4.0 KiB
C++
//===- PostDominators.cpp - Post-Dominator Calculation --------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the post-dominator construction algorithms.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/PostDominators.h"
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#include "llvm/Instructions.h"
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#include "llvm/Support/CFG.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/SetOperations.h"
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#include "PostDominatorCalculation.h"
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using namespace llvm;
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//===----------------------------------------------------------------------===//
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// PostDominatorTree Implementation
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//===----------------------------------------------------------------------===//
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char PostDominatorTree::ID = 0;
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char PostDominanceFrontier::ID = 0;
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static RegisterPass<PostDominatorTree>
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F("postdomtree", "Post-Dominator Tree Construction", true);
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unsigned PostDominatorTree::DFSPass(BasicBlock *V, unsigned N) {
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std::vector<BasicBlock *> workStack;
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SmallPtrSet<BasicBlock *, 32> Visited;
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workStack.push_back(V);
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do {
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BasicBlock *currentBB = workStack.back();
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InfoRec &CurVInfo = Info[currentBB];
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// Visit each block only once.
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if (Visited.insert(currentBB)) {
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CurVInfo.Semi = ++N;
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CurVInfo.Label = currentBB;
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Vertex.push_back(currentBB); // Vertex[n] = current;
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// Info[currentBB].Ancestor = 0;
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// Ancestor[n] = 0
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// Child[currentBB] = 0;
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CurVInfo.Size = 1; // Size[currentBB] = 1
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}
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// Visit children
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bool visitChild = false;
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for (pred_iterator PI = pred_begin(currentBB), PE = pred_end(currentBB);
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PI != PE && !visitChild; ++PI) {
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InfoRec &SuccVInfo = Info[*PI];
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if (SuccVInfo.Semi == 0) {
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SuccVInfo.Parent = currentBB;
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if (!Visited.count(*PI)) {
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workStack.push_back(*PI);
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visitChild = true;
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}
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}
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}
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// If all children are visited or if this block has no child then pop this
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// block out of workStack.
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if (!visitChild)
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workStack.pop_back();
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} while (!workStack.empty());
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return N;
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}
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//===----------------------------------------------------------------------===//
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// PostDominanceFrontier Implementation
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//===----------------------------------------------------------------------===//
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static RegisterPass<PostDominanceFrontier>
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H("postdomfrontier", "Post-Dominance Frontier Construction", true);
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const DominanceFrontier::DomSetType &
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PostDominanceFrontier::calculate(const PostDominatorTree &DT,
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const DomTreeNode *Node) {
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// Loop over CFG successors to calculate DFlocal[Node]
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BasicBlock *BB = Node->getBlock();
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DomSetType &S = Frontiers[BB]; // The new set to fill in...
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if (getRoots().empty()) return S;
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if (BB)
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for (pred_iterator SI = pred_begin(BB), SE = pred_end(BB);
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SI != SE; ++SI) {
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// Does Node immediately dominate this predecessor?
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DomTreeNode *SINode = DT[*SI];
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if (SINode && SINode->getIDom() != Node)
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S.insert(*SI);
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}
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// At this point, S is DFlocal. Now we union in DFup's of our children...
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// Loop through and visit the nodes that Node immediately dominates (Node's
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// children in the IDomTree)
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//
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for (DomTreeNode::const_iterator
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NI = Node->begin(), NE = Node->end(); NI != NE; ++NI) {
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DomTreeNode *IDominee = *NI;
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const DomSetType &ChildDF = calculate(DT, IDominee);
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DomSetType::const_iterator CDFI = ChildDF.begin(), CDFE = ChildDF.end();
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for (; CDFI != CDFE; ++CDFI) {
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if (!DT.properlyDominates(Node, DT[*CDFI]))
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S.insert(*CDFI);
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}
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}
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return S;
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}
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// Ensure that this .cpp file gets linked when PostDominators.h is used.
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DEFINING_FILE_FOR(PostDominanceFrontier)
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