private SlotIndex GetLowerOptimalSplitLocation(LiveInterval liveInterval, SlotIndex at)
{
if (Trace.Active)
{
Trace.Log("--Low Splitting: " + liveInterval.ToString() + " move: " + at.ToString());
}
//a = liveInterval.Start.IsOnHalfStep ? liveInterval.Start : liveInterval.Start.HalfStepForward;
var a = liveInterval.Start;
var blockStart = GetBlockStart(at);
var b = blockStart > liveInterval.Start ? blockStart : null;
if (Trace.Active)
{
Trace.Log(" Block Start : " + (b != null ? b.ToString() : "null"));
}
var c = liveInterval.LiveRange.GetPreviousUsePosition(at);
if (c != null && c.HalfStepForward <= at)
{
c = c.HalfStepForward;
}
if (Trace.Active)
{
Trace.Log(" Previous Use : " + (c != null ? c.ToString() : "null"));
}
var d = liveInterval.LiveRange.GetPreviousDefPosition(at);
if (d != null && d.HalfStepForward <= at)
{
d = d.HalfStepForward;
}
if (Trace.Active)
{
Trace.Log(" Previous Def : " + (d != null ? d.ToString() : "null"));
}
var max = GetMaximum(a, b, c, d);
if (Trace.Active)
{
Trace.Log(" Low Optimal : " + max.ToString());
}
return(max);
}
private SlotIndex GetUpperOptimalSplitLocation(LiveInterval liveInterval, SlotIndex at)
{
if (Trace.Active)
{
Trace.Log("-High Splitting: " + liveInterval.ToString() + " move: " + at.ToString());
}
var a = liveInterval.End;
var blockEnd = GetBlockEnd(at);
var b = blockEnd > liveInterval.End ? blockEnd : null;
if (Trace.Active)
{
Trace.Log(" Block End : " + (b != null ? b.ToString() : "null"));
}
var c = liveInterval.LiveRange.GetNextUsePosition(at);
if (c != null && c.HalfStepBack > at)
{
c = c.HalfStepBack;
}
if (Trace.Active)
{
Trace.Log(" Next Use : " + (c != null ? c.ToString() : "null"));
}
var d = liveInterval.LiveRange.GetNextDefPosition(at);
if (Trace.Active)
{
Trace.Log(" Next Def : " + (d != null ? d.ToString() : "null"));
}
var min = GetMinimum(a, b, c, d);
if (Trace.Active)
{
Trace.Log(" High Optimal : " + min.ToString());
}
return(min);
}
private SlotIndex GetLowOptimalSplitLocation(LiveInterval liveInterval, SlotIndex from, bool check)
{
Debug.Assert(liveInterval.Start != from);
if (trace.Active) trace.Log("--Low Splitting: " + liveInterval.ToString() + " move: " + from.ToString());
if (check)
{
if (liveInterval.UsePositions.Contains(from) || liveInterval.DefPositions.Contains(from))
{
if (trace.Active) trace.Log(" No optimal. Split move: " + from.ToString());
return from;
}
}
SlotIndex blockStart = GetBlockStart(from);
if (trace.Active) trace.Log(" Block Start : " + blockStart.ToString());
SlotIndex lowerBound = blockStart > liveInterval.Start ? blockStart : liveInterval.Start.Next;
if (trace.Active) trace.Log(" Lower Bound : " + lowerBound.ToString());
SlotIndex previousUse = liveInterval.GetPreviousDefOrUsePosition(from);
if (trace.Active) trace.Log(" Previous Use: " + (previousUse != null ? previousUse.ToString() : "null"));
if (previousUse != null && previousUse >= lowerBound)
{
if (trace.Active) trace.Log(" Low Optimal : " + previousUse.Next.ToString());
return previousUse.Next;
}
if (trace.Active) trace.Log(" Low Optimal : " + lowerBound.ToString());
return lowerBound;
}
private SlotIndex GetHighOptimalSplitLocation(LiveInterval liveInterval, SlotIndex after, bool check)
{
Debug.Assert(liveInterval.End != after);
if (trace.Active) trace.Log("--High Splitting: " + liveInterval.ToString() + " move: " + after.ToString());
SlotIndex blockEnd = GetBlockEnd(after);
if (trace.Active) trace.Log(" Block End : " + blockEnd.ToString());
SlotIndex higherBound = blockEnd < liveInterval.End ? blockEnd : liveInterval.End.Previous;
if (trace.Active) trace.Log(" Higher Bound: " + higherBound.ToString());
SlotIndex nextUse = liveInterval.GetNextDefOrUsePosition(after);
if (trace.Active) trace.Log(" Next Use : " + (nextUse != null ? nextUse.ToString() : "null"));
if (nextUse != null && nextUse <= higherBound)
{
if (trace.Active) trace.Log(" High Optimal: " + nextUse.Previous.ToString());
return nextUse;
}
if (trace.Active) trace.Log(" High Optimal: " + higherBound.ToString());
return higherBound;
}
private void ProcessLiveInterval(LiveInterval liveInterval)
{
if (trace.Active)
{
trace.Log("Processing Interval: " + liveInterval.ToString() + " / Length: " + liveInterval.Length.ToString() + " / Spill Cost: " + liveInterval.SpillCost.ToString() + " / Stage: " + liveInterval.Stage.ToString());
trace.Log(" Defs (" + liveInterval.DefPositions.Count.ToString() + "): " + SlotsToString(liveInterval.DefPositions));
trace.Log(" Uses (" + liveInterval.UsePositions.Count.ToString() + "): " + SlotsToString(liveInterval.UsePositions));
}
if (liveInterval.ForceSpilled)
{
if (trace.Active) trace.Log(" Forced spilled interval");
liveInterval.VirtualRegister.IsSpilled = true;
spilledIntervals.Add(liveInterval);
return;
}
// For now, empty intervals will stay spilled
if (liveInterval.IsEmpty)
{
if (trace.Active) trace.Log(" Spilled");
liveInterval.VirtualRegister.IsSpilled = true;
spilledIntervals.Add(liveInterval);
return;
}
var moveHints = GetMoveHints(liveInterval);
// Try to place using move hints first
if (PlaceLiveIntervalOnTrack(liveInterval, moveHints))
{
UpdateMoveHints(liveInterval, moveHints);
return;
}
// TODO - try move hints first, allow evictions
// Find any available track and place interval there
if (PlaceLiveIntervalOnAnyAvailableTrack(liveInterval))
{
UpdateMoveHints(liveInterval, moveHints);
return;
}
if (trace.Active) trace.Log(" No free register available");
// No place for live interval; find live interval(s) to evict based on spill costs
if (PlaceLiveIntervalOnTrackAllowEvictions(liveInterval))
{
UpdateMoveHints(liveInterval, moveHints);
return;
}
if (trace.Active) trace.Log(" No live intervals to evicts");
// No live intervals to evict!
// prepare to split live interval
if (liveInterval.Stage == LiveInterval.AllocationStage.Initial)
{
if (trace.Active) trace.Log(" Re-queued for split level 1 stage");
liveInterval.Stage = LiveInterval.AllocationStage.SplitLevel1;
AddPriorityQueue(liveInterval);
return;
}
// split live interval - level 1
if (liveInterval.Stage == LiveInterval.AllocationStage.SplitLevel1)
{
if (trace.Active) trace.Log(" Attempting to split interval - level 1");
if (TrySplitInterval(liveInterval, 1))
{
return;
}
// Move to split level 2 stage
if (trace.Active) trace.Log(" Re-queued for split interval - level 2");
liveInterval.Stage = LiveInterval.AllocationStage.SplitLevel2;
AddPriorityQueue(liveInterval);
return;
}
// split live interval - level 2
if (liveInterval.Stage == LiveInterval.AllocationStage.SplitLevel2)
{
if (trace.Active) trace.Log(" Attempting to split interval - level 2");
if (TrySplitInterval(liveInterval, 2))
{
return;
}
// Move to spill stage
if (trace.Active) trace.Log(" Re-queued for spillable stage");
liveInterval.Stage = LiveInterval.AllocationStage.Spillable;
AddPriorityQueue(liveInterval);
return;
}
// spill interval to stack slot
if (liveInterval.Stage == LiveInterval.AllocationStage.Spillable)
{
if (trace.Active) trace.Log(" Spilled interval");
//liveInterval.Stage = LiveInterval.AllocationStage.Spilled
liveInterval.VirtualRegister.IsSpilled = true;
spilledIntervals.Add(liveInterval);
return;
}
// TODO
return;
}
private SlotIndex GetUpperOptimalSplitLocation(LiveInterval liveInterval, SlotIndex at)
{
if (Trace.Active) Trace.Log("--High Splitting: " + liveInterval.ToString() + " move: " + at.ToString());
var a = liveInterval.End;
var blockEnd = GetBlockEnd(at);
var b = blockEnd > liveInterval.End ? blockEnd : null;
if (Trace.Active) Trace.Log(" Block End : " + (b != null ? b.ToString() : "null"));
var c = liveInterval.LiveRange.GetNextUsePosition(at);
if (c != null && c.HalfStepBack > at)
c = c.HalfStepBack;
if (Trace.Active) Trace.Log(" Next Use : " + (c != null ? c.ToString() : "null"));
var d = liveInterval.LiveRange.GetNextDefPosition(at);
if (Trace.Active) Trace.Log(" Next Def : " + (d != null ? d.ToString() : "null"));
var min = GetMinimum(a, b, c, d);
if (Trace.Active) Trace.Log(" High Optimal : " + min.ToString());
return min;
}
private SlotIndex GetLowerOptimalSplitLocation(LiveInterval liveInterval, SlotIndex at)
{
if (Trace.Active) Trace.Log("--Low Splitting: " + liveInterval.ToString() + " move: " + at.ToString());
//a = liveInterval.Start.IsOnHalfStep ? liveInterval.Start : liveInterval.Start.HalfStepForward;
var a = liveInterval.Start;
var blockStart = GetBlockStart(at);
var b = blockStart > liveInterval.Start ? blockStart : null;
if (Trace.Active) Trace.Log(" Block Start : " + (b != null ? b.ToString() : "null"));
var c = liveInterval.LiveRange.GetPreviousUsePosition(at);
if (c != null && c.HalfStepForward <= at)
c = c.HalfStepForward;
if (Trace.Active) Trace.Log(" Previous Use : " + (c != null ? c.ToString() : "null"));
var d = liveInterval.LiveRange.GetPreviousDefPosition(at);
if (d != null && d.HalfStepForward <= at)
d = d.HalfStepForward;
if (Trace.Active) Trace.Log(" Previous Def : " + (d != null ? d.ToString() : "null"));
var max = GetMaximum(a, b, c, d);
if (Trace.Active) Trace.Log(" Low Optimal : " + max.ToString());
return max;
}