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//===- 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.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "postdomtree"
#include "llvm/Analysis/PostDominators.h"
#include "llvm/Instructions.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SetOperations.h"
#include "llvm/Analysis/DominatorInternals.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
// PostDominatorTree Implementation
//===----------------------------------------------------------------------===//
char PostDominatorTree::ID = 0;
char PostDominanceFrontier::ID = 0;
static RegisterPass<PostDominatorTree>
F("postdomtree", "Post-Dominator Tree Construction", true, true);
bool PostDominatorTree::runOnFunction(Function &F) {
DT->recalculate(F);
DEBUG(DT->print(errs()));
return false;
}
PostDominatorTree::~PostDominatorTree() {
delete DT;
}
void PostDominatorTree::print(raw_ostream &OS, const Module *) const {
DT->print(OS);
}
FunctionPass* llvm::createPostDomTree() {
return new PostDominatorTree();
}
//===----------------------------------------------------------------------===//
// PostDominanceFrontier Implementation
//===----------------------------------------------------------------------===//
static RegisterPass<PostDominanceFrontier>
H("postdomfrontier", "Post-Dominance Frontier Construction", true, 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::createPostDomFrontier() {
return new PostDominanceFrontier();
}
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