public static Dictionary <BasicBlock <IRInstrList>, BlockLiveness> ComputeLiveness(
IList <BasicBlock <IRInstrList> > blocks)
{
var liveness = new Dictionary <BasicBlock <IRInstrList>, BlockLiveness>();
var entryBlocks = blocks.Where(block => block.Sources.Count == 0).ToList();
var order = new List <BasicBlock <IRInstrList> >();
var visited = new HashSet <BasicBlock <IRInstrList> >();
foreach (var entry in entryBlocks)
{
PostorderTraversal(entry, visited, block => order.Add(block));
}
var worked = false;
do
{
foreach (var currentBlock in order)
{
var blockLiveness = BlockLiveness.Empty();
foreach (var successor in currentBlock.Targets)
{
BlockLiveness successorLiveness;
if (!liveness.TryGetValue(successor, out successorLiveness))
{
continue;
}
blockLiveness.OutLive.UnionWith(successorLiveness.InLive);
}
var live = new HashSet <IRVariable>(blockLiveness.OutLive);
for (var i = currentBlock.Content.Count - 1; i >= 0; i--)
{
var instr = currentBlock.Content[i];
ComputeInstrLiveness(instr, live);
}
blockLiveness.InLive.UnionWith(live);
BlockLiveness prevLiveness;
if (!worked && liveness.TryGetValue(currentBlock, out prevLiveness))
{
worked = !prevLiveness.InLive.SetEquals(blockLiveness.InLive) ||
!prevLiveness.OutLive.SetEquals(blockLiveness.OutLive);
}
liveness[currentBlock] = blockLiveness;
}
} while(worked);
return(liveness);
}
public static Dictionary <IRInstruction, HashSet <IRVariable> > ComputeLiveness(
BasicBlock <IRInstrList> block, BlockLiveness liveness)
{
var ret = new Dictionary <IRInstruction, HashSet <IRVariable> >();
var live = new HashSet <IRVariable>(liveness.OutLive);
for (var i = block.Content.Count - 1; i >= 0; i--)
{
var instr = block.Content[i];
ComputeInstrLiveness(instr, live);
ret[instr] = new HashSet <IRVariable>(live);
}
Debug.Assert(live.SetEquals(liveness.InLive));
return(ret);
}