bool LoopControllersDepGraph::runOnFunction(Function& F){
//Step 1: Get the complete dependence graph
functionDepGraph& DepGraph = getAnalysis<functionDepGraph> ();
depGraph = DepGraph.depGraph;
//Step 2: Get the list of values that control the loop exit
LoopInfoEx& li = getAnalysis<LoopInfoEx>();
std::set<Value*> loopExitPredicates;
for (LoopInfoEx::iterator lit = li.begin(), lend = li.end(); lit != lend; lit++) {
Loop* l = *lit;
SmallVector<BasicBlock*, 4> loopExitingBlocks;
l->getExitingBlocks(loopExitingBlocks);
for(SmallVectorImpl<BasicBlock*>::iterator BB = loopExitingBlocks.begin(); BB != loopExitingBlocks.end(); BB++){
if (BranchInst* BI = dyn_cast<BranchInst>((*BB)->getTerminator())) {
loopExitPredicates.insert(BI->getCondition());
} else if (SwitchInst* SI = dyn_cast<SwitchInst>((*BB)->getTerminator())) {
loopExitPredicates.insert(SI->getCondition());
} else if (IndirectBrInst* IBI = dyn_cast<IndirectBrInst>((*BB)->getTerminator())) {
loopExitPredicates.insert(IBI->getAddress());
} else if (InvokeInst* II = dyn_cast<InvokeInst>((*BB)->getTerminator())) {
loopExitPredicates.insert(II);
}
}
}
//Step 3: Make a list of graph nodes that represent the dependencies of the loop controllers
std::set<GraphNode*> visitedNodes;
for(std::set<Value*>::iterator v = loopExitPredicates.begin(); v != loopExitPredicates.end(); v++){
if (GraphNode* valueNode = depGraph->findNode(*v))
depGraph->dfsVisitBack(valueNode, visitedNodes);
else
errs() << "Function : " << F.getName() << " - Value not found in the graph : " << **v
<< "\n";
}
//Step 4: Remove from the graph all the nodes that are not in the list of dependencies
std::set<GraphNode*> nodesToRemove;
for(DepGraph::iterator node = depGraph->begin(); node != depGraph->end(); node++ ){
if (!visitedNodes.count(*node)) nodesToRemove.insert(*node);
}
for(std::set<GraphNode*>::iterator node = nodesToRemove.begin(); node != nodesToRemove.end(); node++ ){
depGraph->removeNode(*node);
}
//Step 5: ta-da! The graph is ready to use :)
fullGraph = depGraph;
return false;
}
