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69093cf2d6
* Optimize `TryAllocateRegWithtoutSpill` a bit * Add a fast path for when all registers are live. * Do not query `GetOverlapPosition` if the register is already in use (i.e: free position is 0). * Do not allocate child split list if not parent * Turn `LiveRange` into a reference struct `LiveRange` is now a reference wrapping struct like `Operand` and `Operation`. It has also been changed into a singly linked-list. In micro-benchmarks traversing the linked-list was faster than binary search on `List<T>`. Even for quite large input sizes (e.g: 1,000,000), surprisingly. Could be because the code gen for traversing the linked-list is much much cleaner and there is no virtual dispatch happening when checking if intervals overlaps. * Turn `LiveInterval` into an iterator The LSRA allocates in forward order and never inspect previous `LiveInterval` once they are expired. Something similar can be done for the `LiveRange`s within the `LiveInterval`s themselves. The `LiveInterval` is turned into a iterator which expires `LiveRange` within it. The iterator is moved forward along with interval walking code, i.e: AllocateInterval(context, interval, cIndex). * Remove `LinearScanAllocator.Sources` Local methods are less susceptible to do allocations than lambdas. * Optimize `GetOverlapPosition(interval)` a bit Time complexity should be in O(n+m) instead of O(nm) now. * Optimize `NumberLocals` a bit Use the same idea as in `HybridAllocator` to store the visited state in the MSB of the Operand's value instead of using a `HashSet<T>`. * Optimize `InsertSplitCopies` a bit Avoid allocating a redundant `CopyResolver`. * Optimize `InsertSplitCopiesAtEdges` a bit Avoid redundant allocations of `CopyResolver`. * Use stack allocation for `freePositions` Avoid redundant computations. * Add `UseList` Replace `SortedIntegerList` with an even more specialized data structure. It allocates memory on the arena allocators and does not require copying use positions when splitting it. * Turn `LiveInterval` into a reference struct `LiveInterval` is now a reference wrapping struct like `Operand` and `Operation`. The rationale behind turning this in a reference wrapping struct is because a `LiveInterval` is associated with each local variable, and these intervals may themselves be split further. I've seen translations having up to 8000 local variables. To make the `LiveInterval` unmanaged, a new data structure called `LiveIntervalList` was added to store child splits. This differs from `SortedList<,>` because it can contain intervals with the same start position. Really wished we got some more of C++ template in C#. :^( * Optimize `GetChildSplit` a bit No need to inspect the remaining ranges if we've reached a range which starts after position, since the split list is ordered. * Optimize `CopyResolver` a bit Lazily allocate the fill, spill and parallel copy structures since most of the time only one of them is needed. * Optimize `BitMap.Enumerator` a bit Marking `MoveNext` as `AggressiveInlining` allows RyuJIT to promote the `Enumerator` struct into registers completely, reducing load/store code a lot since it does not have to store the struct on the stack for ABI purposes. * Use stack allocation for `use/blockedPositions` * Optimize `AllocateWithSpill` a bit * Address feedback * Make `LiveInterval.AddRange(,)` more conservative Produces no diff against master, but just for good measure.
1099 lines
No EOL
38 KiB
C#
1099 lines
No EOL
38 KiB
C#
using ARMeilleure.Common;
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using ARMeilleure.IntermediateRepresentation;
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using ARMeilleure.Translation;
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using System;
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using System.Collections.Generic;
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using System.Diagnostics;
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using System.Linq;
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using System.Numerics;
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namespace ARMeilleure.CodeGen.RegisterAllocators
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{
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// Based on:
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// "Linear Scan Register Allocation for the Java(tm) HotSpot Client Compiler".
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// http://www.christianwimmer.at/Publications/Wimmer04a/Wimmer04a.pdf
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class LinearScanAllocator : IRegisterAllocator
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{
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private const int InstructionGap = 2;
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private const int InstructionGapMask = InstructionGap - 1;
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private const int RegistersCount = 16;
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private HashSet<int> _blockEdges;
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private LiveRange[] _blockRanges;
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private BitMap[] _blockLiveIn;
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private List<LiveInterval> _intervals;
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private LiveInterval[] _parentIntervals;
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private List<(IntrusiveList<Operation>, Operation)> _operationNodes;
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private int _operationsCount;
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private class AllocationContext
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{
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public RegisterMasks Masks { get; }
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public StackAllocator StackAlloc { get; }
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public BitMap Active { get; }
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public BitMap Inactive { get; }
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public int IntUsedRegisters { get; set; }
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public int VecUsedRegisters { get; set; }
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private readonly int[] _intFreePositions;
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private readonly int[] _vecFreePositions;
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private readonly int _intFreePositionsCount;
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private readonly int _vecFreePositionsCount;
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public AllocationContext(StackAllocator stackAlloc, RegisterMasks masks, int intervalsCount)
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{
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StackAlloc = stackAlloc;
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Masks = masks;
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Active = new BitMap(Allocators.Default, intervalsCount);
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Inactive = new BitMap(Allocators.Default, intervalsCount);
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PopulateFreePositions(RegisterType.Integer, out _intFreePositions, out _intFreePositionsCount);
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PopulateFreePositions(RegisterType.Vector, out _vecFreePositions, out _vecFreePositionsCount);
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void PopulateFreePositions(RegisterType type, out int[] positions, out int count)
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{
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positions = new int[RegistersCount];
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count = BitOperations.PopCount((uint)masks.GetAvailableRegisters(type));
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int mask = masks.GetAvailableRegisters(type);
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for (int i = 0; i < positions.Length; i++)
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{
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if ((mask & (1 << i)) != 0)
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{
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positions[i] = int.MaxValue;
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}
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}
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}
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}
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public void GetFreePositions(RegisterType type, in Span<int> positions, out int count)
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{
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if (type == RegisterType.Integer)
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{
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_intFreePositions.CopyTo(positions);
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count = _intFreePositionsCount;
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}
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else
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{
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Debug.Assert(type == RegisterType.Vector);
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_vecFreePositions.CopyTo(positions);
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count = _vecFreePositionsCount;
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}
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}
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public void MoveActiveToInactive(int bit)
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{
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Move(Active, Inactive, bit);
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}
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public void MoveInactiveToActive(int bit)
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{
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Move(Inactive, Active, bit);
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}
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private static void Move(BitMap source, BitMap dest, int bit)
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{
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source.Clear(bit);
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dest.Set(bit);
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}
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}
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public AllocationResult RunPass(
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ControlFlowGraph cfg,
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StackAllocator stackAlloc,
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RegisterMasks regMasks)
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{
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NumberLocals(cfg);
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var context = new AllocationContext(stackAlloc, regMasks, _intervals.Count);
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BuildIntervals(cfg, context);
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for (int index = 0; index < _intervals.Count; index++)
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{
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LiveInterval current = _intervals[index];
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if (current.IsEmpty)
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{
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continue;
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}
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if (current.IsFixed)
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{
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context.Active.Set(index);
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if (current.Register.Type == RegisterType.Integer)
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{
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context.IntUsedRegisters |= 1 << current.Register.Index;
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}
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else /* if (interval.Register.Type == RegisterType.Vector) */
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{
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context.VecUsedRegisters |= 1 << current.Register.Index;
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}
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continue;
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}
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AllocateInterval(context, current, index);
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}
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for (int index = RegistersCount * 2; index < _intervals.Count; index++)
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{
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if (!_intervals[index].IsSpilled)
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{
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ReplaceLocalWithRegister(_intervals[index]);
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}
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}
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InsertSplitCopies();
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InsertSplitCopiesAtEdges(cfg);
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return new AllocationResult(context.IntUsedRegisters, context.VecUsedRegisters, context.StackAlloc.TotalSize);
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}
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private void AllocateInterval(AllocationContext context, LiveInterval current, int cIndex)
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{
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// Check active intervals that already ended.
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foreach (int iIndex in context.Active)
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{
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LiveInterval interval = _intervals[iIndex];
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interval.Forward(current.GetStart());
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if (interval.GetEnd() < current.GetStart())
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{
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context.Active.Clear(iIndex);
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}
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else if (!interval.Overlaps(current.GetStart()))
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{
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context.MoveActiveToInactive(iIndex);
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}
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}
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// Check inactive intervals that already ended or were reactivated.
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foreach (int iIndex in context.Inactive)
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{
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LiveInterval interval = _intervals[iIndex];
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interval.Forward(current.GetStart());
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if (interval.GetEnd() < current.GetStart())
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{
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context.Inactive.Clear(iIndex);
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}
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else if (interval.Overlaps(current.GetStart()))
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{
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context.MoveInactiveToActive(iIndex);
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}
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}
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if (!TryAllocateRegWithoutSpill(context, current, cIndex))
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{
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AllocateRegWithSpill(context, current, cIndex);
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}
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}
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private bool TryAllocateRegWithoutSpill(AllocationContext context, LiveInterval current, int cIndex)
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{
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RegisterType regType = current.Local.Type.ToRegisterType();
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Span<int> freePositions = stackalloc int[RegistersCount];
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context.GetFreePositions(regType, freePositions, out int freePositionsCount);
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foreach (int iIndex in context.Active)
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{
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LiveInterval interval = _intervals[iIndex];
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Register reg = interval.Register;
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if (reg.Type == regType)
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{
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freePositions[reg.Index] = 0;
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freePositionsCount--;
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}
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}
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// If all registers are already active, return early. No point in inspecting the inactive set to look for
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// holes.
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if (freePositionsCount == 0)
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{
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return false;
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}
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foreach (int iIndex in context.Inactive)
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{
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LiveInterval interval = _intervals[iIndex];
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Register reg = interval.Register;
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ref int freePosition = ref freePositions[reg.Index];
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if (reg.Type == regType && freePosition != 0)
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{
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int overlapPosition = interval.GetOverlapPosition(current);
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if (overlapPosition != LiveInterval.NotFound && freePosition > overlapPosition)
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{
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freePosition = overlapPosition;
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}
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}
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}
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int selectedReg = GetHighestValueIndex(freePositions);
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int selectedNextUse = freePositions[selectedReg];
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// Intervals starts and ends at odd positions, unless they span an entire
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// block, in this case they will have ranges at a even position.
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// When a interval is loaded from the stack to a register, we can only
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// do the split at a odd position, because otherwise the split interval
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// that is inserted on the list to be processed may clobber a register
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// used by the instruction at the same position as the split.
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// The problem only happens when a interval ends exactly at this instruction,
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// because otherwise they would interfere, and the register wouldn't be selected.
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// When the interval is aligned and the above happens, there's no problem as
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// the instruction that is actually with the last use is the one
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// before that position.
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selectedNextUse &= ~InstructionGapMask;
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if (selectedNextUse <= current.GetStart())
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{
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return false;
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}
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else if (selectedNextUse < current.GetEnd())
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{
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LiveInterval splitChild = current.Split(selectedNextUse);
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if (splitChild.UsesCount != 0)
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{
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Debug.Assert(splitChild.GetStart() > current.GetStart(), "Split interval has an invalid start position.");
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InsertInterval(splitChild);
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}
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else
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{
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Spill(context, splitChild);
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}
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}
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current.Register = new Register(selectedReg, regType);
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if (regType == RegisterType.Integer)
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{
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context.IntUsedRegisters |= 1 << selectedReg;
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}
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else /* if (regType == RegisterType.Vector) */
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{
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context.VecUsedRegisters |= 1 << selectedReg;
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}
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context.Active.Set(cIndex);
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return true;
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}
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private void AllocateRegWithSpill(AllocationContext context, LiveInterval current, int cIndex)
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{
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RegisterType regType = current.Local.Type.ToRegisterType();
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Span<int> usePositions = stackalloc int[RegistersCount];
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Span<int> blockedPositions = stackalloc int[RegistersCount];
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context.GetFreePositions(regType, usePositions, out _);
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context.GetFreePositions(regType, blockedPositions, out _);
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foreach (int iIndex in context.Active)
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{
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LiveInterval interval = _intervals[iIndex];
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Register reg = interval.Register;
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if (reg.Type == regType)
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{
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ref int usePosition = ref usePositions[reg.Index];
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ref int blockedPosition = ref blockedPositions[reg.Index];
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if (interval.IsFixed)
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{
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usePosition = 0;
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blockedPosition = 0;
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}
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else
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{
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int nextUse = interval.NextUseAfter(current.GetStart());
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if (nextUse != LiveInterval.NotFound && usePosition > nextUse)
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{
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usePosition = nextUse;
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}
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}
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}
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}
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foreach (int iIndex in context.Inactive)
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{
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LiveInterval interval = _intervals[iIndex];
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Register reg = interval.Register;
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if (reg.Type == regType)
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{
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ref int usePosition = ref usePositions[reg.Index];
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ref int blockedPosition = ref blockedPositions[reg.Index];
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if (interval.IsFixed)
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{
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int overlapPosition = interval.GetOverlapPosition(current);
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if (overlapPosition != LiveInterval.NotFound)
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{
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blockedPosition = Math.Min(blockedPosition, overlapPosition);
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usePosition = Math.Min(usePosition, overlapPosition);
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}
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}
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else if (interval.Overlaps(current))
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{
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int nextUse = interval.NextUseAfter(current.GetStart());
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if (nextUse != LiveInterval.NotFound && usePosition > nextUse)
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{
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usePosition = nextUse;
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}
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}
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}
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}
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int selectedReg = GetHighestValueIndex(usePositions);
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int currentFirstUse = current.FirstUse();
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Debug.Assert(currentFirstUse >= 0, "Current interval has no uses.");
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if (usePositions[selectedReg] < currentFirstUse)
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{
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// All intervals on inactive and active are being used before current,
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// so spill the current interval.
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Debug.Assert(currentFirstUse > current.GetStart(), "Trying to spill a interval currently being used.");
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LiveInterval splitChild = current.Split(currentFirstUse);
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Debug.Assert(splitChild.GetStart() > current.GetStart(), "Split interval has an invalid start position.");
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InsertInterval(splitChild);
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Spill(context, current);
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}
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else if (blockedPositions[selectedReg] > current.GetEnd())
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{
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// Spill made the register available for the entire current lifetime,
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// so we only need to split the intervals using the selected register.
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current.Register = new Register(selectedReg, regType);
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SplitAndSpillOverlappingIntervals(context, current);
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context.Active.Set(cIndex);
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}
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else
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{
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// There are conflicts even after spill due to the use of fixed registers
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// that can't be spilled, so we need to also split current at the point of
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// the first fixed register use.
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current.Register = new Register(selectedReg, regType);
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int splitPosition = blockedPositions[selectedReg] & ~InstructionGapMask;
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Debug.Assert(splitPosition > current.GetStart(), "Trying to split a interval at a invalid position.");
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LiveInterval splitChild = current.Split(splitPosition);
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if (splitChild.UsesCount != 0)
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{
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Debug.Assert(splitChild.GetStart() > current.GetStart(), "Split interval has an invalid start position.");
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InsertInterval(splitChild);
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}
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else
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{
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Spill(context, splitChild);
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}
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SplitAndSpillOverlappingIntervals(context, current);
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context.Active.Set(cIndex);
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}
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}
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private static int GetHighestValueIndex(Span<int> span)
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{
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int highest = span[0];
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if (highest == int.MaxValue)
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{
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return 0;
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}
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int selected = 0;
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for (int index = 1; index < span.Length; index++)
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{
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int current = span[index];
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if (highest < current)
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{
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highest = current;
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selected = index;
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if (current == int.MaxValue)
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{
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break;
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}
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}
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}
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return selected;
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}
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private void SplitAndSpillOverlappingIntervals(AllocationContext context, LiveInterval current)
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{
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foreach (int iIndex in context.Active)
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{
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LiveInterval interval = _intervals[iIndex];
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if (!interval.IsFixed && interval.Register == current.Register)
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{
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SplitAndSpillOverlappingInterval(context, current, interval);
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context.Active.Clear(iIndex);
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}
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}
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foreach (int iIndex in context.Inactive)
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{
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LiveInterval interval = _intervals[iIndex];
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if (!interval.IsFixed && interval.Register == current.Register && interval.Overlaps(current))
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{
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SplitAndSpillOverlappingInterval(context, current, interval);
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context.Inactive.Clear(iIndex);
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}
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}
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}
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private void SplitAndSpillOverlappingInterval(
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AllocationContext context,
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LiveInterval current,
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LiveInterval interval)
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{
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// If there's a next use after the start of the current interval,
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// we need to split the spilled interval twice, and re-insert it
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// on the "pending" list to ensure that it will get a new register
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// on that use position.
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int nextUse = interval.NextUseAfter(current.GetStart());
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LiveInterval splitChild;
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if (interval.GetStart() < current.GetStart())
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{
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splitChild = interval.Split(current.GetStart());
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}
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else
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{
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splitChild = interval;
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}
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if (nextUse != -1)
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{
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Debug.Assert(nextUse > current.GetStart(), "Trying to spill a interval currently being used.");
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if (nextUse > splitChild.GetStart())
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{
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LiveInterval right = splitChild.Split(nextUse);
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Spill(context, splitChild);
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splitChild = right;
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}
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InsertInterval(splitChild);
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}
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else
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{
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Spill(context, splitChild);
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}
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}
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private void InsertInterval(LiveInterval interval)
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{
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Debug.Assert(interval.UsesCount != 0, "Trying to insert a interval without uses.");
|
|
Debug.Assert(!interval.IsEmpty, "Trying to insert a empty interval.");
|
|
Debug.Assert(!interval.IsSpilled, "Trying to insert a spilled interval.");
|
|
|
|
int startIndex = RegistersCount * 2;
|
|
|
|
int insertIndex = _intervals.BinarySearch(startIndex, _intervals.Count - startIndex, interval, null);
|
|
|
|
if (insertIndex < 0)
|
|
{
|
|
insertIndex = ~insertIndex;
|
|
}
|
|
|
|
_intervals.Insert(insertIndex, interval);
|
|
}
|
|
|
|
private void Spill(AllocationContext context, LiveInterval interval)
|
|
{
|
|
Debug.Assert(!interval.IsFixed, "Trying to spill a fixed interval.");
|
|
Debug.Assert(interval.UsesCount == 0, "Trying to spill a interval with uses.");
|
|
|
|
// We first check if any of the siblings were spilled, if so we can reuse
|
|
// the stack offset. Otherwise, we allocate a new space on the stack.
|
|
// This prevents stack-to-stack copies being necessary for a split interval.
|
|
if (!interval.TrySpillWithSiblingOffset())
|
|
{
|
|
interval.Spill(context.StackAlloc.Allocate(interval.Local.Type));
|
|
}
|
|
}
|
|
|
|
private void InsertSplitCopies()
|
|
{
|
|
Dictionary<int, CopyResolver> copyResolvers = new Dictionary<int, CopyResolver>();
|
|
|
|
CopyResolver GetCopyResolver(int position)
|
|
{
|
|
if (!copyResolvers.TryGetValue(position, out CopyResolver copyResolver))
|
|
{
|
|
copyResolver = new CopyResolver();
|
|
|
|
copyResolvers.Add(position, copyResolver);
|
|
}
|
|
|
|
return copyResolver;
|
|
}
|
|
|
|
foreach (LiveInterval interval in _intervals.Where(x => x.IsSplit))
|
|
{
|
|
LiveInterval previous = interval;
|
|
|
|
foreach (LiveInterval splitChild in interval.SplitChildren())
|
|
{
|
|
int splitPosition = splitChild.GetStart();
|
|
|
|
if (!_blockEdges.Contains(splitPosition) && previous.GetEnd() == splitPosition)
|
|
{
|
|
GetCopyResolver(splitPosition).AddSplit(previous, splitChild);
|
|
}
|
|
|
|
previous = splitChild;
|
|
}
|
|
}
|
|
|
|
foreach (KeyValuePair<int, CopyResolver> kv in copyResolvers)
|
|
{
|
|
CopyResolver copyResolver = kv.Value;
|
|
|
|
if (!copyResolver.HasCopy)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
int splitPosition = kv.Key;
|
|
|
|
(IntrusiveList<Operation> nodes, Operation node) = GetOperationNode(splitPosition);
|
|
|
|
Operation[] sequence = copyResolver.Sequence();
|
|
|
|
nodes.AddBefore(node, sequence[0]);
|
|
|
|
node = sequence[0];
|
|
|
|
for (int index = 1; index < sequence.Length; index++)
|
|
{
|
|
nodes.AddAfter(node, sequence[index]);
|
|
|
|
node = sequence[index];
|
|
}
|
|
}
|
|
}
|
|
|
|
private void InsertSplitCopiesAtEdges(ControlFlowGraph cfg)
|
|
{
|
|
int blocksCount = cfg.Blocks.Count;
|
|
|
|
bool IsSplitEdgeBlock(BasicBlock block)
|
|
{
|
|
return block.Index >= blocksCount;
|
|
}
|
|
|
|
// Reset iterators to beginning because GetSplitChild depends on the state of the iterator.
|
|
foreach (LiveInterval interval in _intervals)
|
|
{
|
|
interval.Reset();
|
|
}
|
|
|
|
for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
|
|
{
|
|
if (IsSplitEdgeBlock(block))
|
|
{
|
|
continue;
|
|
}
|
|
|
|
bool hasSingleOrNoSuccessor = block.SuccessorsCount <= 1;
|
|
|
|
for (int i = 0; i < block.SuccessorsCount; i++)
|
|
{
|
|
BasicBlock successor = block.GetSuccessor(i);
|
|
|
|
int succIndex = successor.Index;
|
|
|
|
// If the current node is a split node, then the actual successor node
|
|
// (the successor before the split) should be right after it.
|
|
if (IsSplitEdgeBlock(successor))
|
|
{
|
|
succIndex = successor.GetSuccessor(0).Index;
|
|
}
|
|
|
|
CopyResolver copyResolver = null;
|
|
|
|
foreach (int iIndex in _blockLiveIn[succIndex])
|
|
{
|
|
LiveInterval interval = _parentIntervals[iIndex];
|
|
|
|
if (!interval.IsSplit)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
int lEnd = _blockRanges[block.Index].End - 1;
|
|
int rStart = _blockRanges[succIndex].Start;
|
|
|
|
LiveInterval left = interval.GetSplitChild(lEnd);
|
|
LiveInterval right = interval.GetSplitChild(rStart);
|
|
|
|
if (left != default && right != default && left != right)
|
|
{
|
|
if (copyResolver == null)
|
|
{
|
|
copyResolver = new CopyResolver();
|
|
}
|
|
|
|
copyResolver.AddSplit(left, right);
|
|
}
|
|
}
|
|
|
|
if (copyResolver == null || !copyResolver.HasCopy)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
Operation[] sequence = copyResolver.Sequence();
|
|
|
|
if (hasSingleOrNoSuccessor)
|
|
{
|
|
foreach (Operation operation in sequence)
|
|
{
|
|
block.Append(operation);
|
|
}
|
|
}
|
|
else if (successor.Predecessors.Count == 1)
|
|
{
|
|
successor.Operations.AddFirst(sequence[0]);
|
|
|
|
Operation prependNode = sequence[0];
|
|
|
|
for (int index = 1; index < sequence.Length; index++)
|
|
{
|
|
Operation operation = sequence[index];
|
|
|
|
successor.Operations.AddAfter(prependNode, operation);
|
|
|
|
prependNode = operation;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// Split the critical edge.
|
|
BasicBlock splitBlock = cfg.SplitEdge(block, successor);
|
|
|
|
foreach (Operation operation in sequence)
|
|
{
|
|
splitBlock.Append(operation);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
private void ReplaceLocalWithRegister(LiveInterval current)
|
|
{
|
|
Operand register = GetRegister(current);
|
|
|
|
foreach (int usePosition in current.UsePositions())
|
|
{
|
|
(_, Operation operation) = GetOperationNode(usePosition);
|
|
|
|
for (int index = 0; index < operation.SourcesCount; index++)
|
|
{
|
|
Operand source = operation.GetSource(index);
|
|
|
|
if (source == current.Local)
|
|
{
|
|
operation.SetSource(index, register);
|
|
}
|
|
else if (source.Kind == OperandKind.Memory)
|
|
{
|
|
MemoryOperand memOp = source.GetMemory();
|
|
|
|
if (memOp.BaseAddress == current.Local)
|
|
{
|
|
memOp.BaseAddress = register;
|
|
}
|
|
|
|
if (memOp.Index == current.Local)
|
|
{
|
|
memOp.Index = register;
|
|
}
|
|
}
|
|
}
|
|
|
|
for (int index = 0; index < operation.DestinationsCount; index++)
|
|
{
|
|
Operand dest = operation.GetDestination(index);
|
|
|
|
if (dest == current.Local)
|
|
{
|
|
operation.SetDestination(index, register);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
private static Operand GetRegister(LiveInterval interval)
|
|
{
|
|
Debug.Assert(!interval.IsSpilled, "Spilled intervals are not allowed.");
|
|
|
|
return Operand.Factory.Register(
|
|
interval.Register.Index,
|
|
interval.Register.Type,
|
|
interval.Local.Type);
|
|
}
|
|
|
|
private (IntrusiveList<Operation>, Operation) GetOperationNode(int position)
|
|
{
|
|
return _operationNodes[position / InstructionGap];
|
|
}
|
|
|
|
private void NumberLocals(ControlFlowGraph cfg)
|
|
{
|
|
_operationNodes = new List<(IntrusiveList<Operation>, Operation)>();
|
|
_intervals = new List<LiveInterval>();
|
|
|
|
for (int index = 0; index < RegistersCount; index++)
|
|
{
|
|
_intervals.Add(new LiveInterval(new Register(index, RegisterType.Integer)));
|
|
_intervals.Add(new LiveInterval(new Register(index, RegisterType.Vector)));
|
|
}
|
|
|
|
// The "visited" state is stored in the MSB of the local's value.
|
|
const ulong VisitedMask = 1ul << 63;
|
|
|
|
bool IsVisited(Operand local)
|
|
{
|
|
return (local.GetValueUnsafe() & VisitedMask) != 0;
|
|
}
|
|
|
|
void SetVisited(Operand local)
|
|
{
|
|
local.GetValueUnsafe() |= VisitedMask;
|
|
}
|
|
|
|
_operationsCount = 0;
|
|
|
|
for (int index = cfg.PostOrderBlocks.Length - 1; index >= 0; index--)
|
|
{
|
|
BasicBlock block = cfg.PostOrderBlocks[index];
|
|
|
|
for (Operation node = block.Operations.First; node != default; node = node.ListNext)
|
|
{
|
|
_operationNodes.Add((block.Operations, node));
|
|
|
|
for (int i = 0; i < node.DestinationsCount; i++)
|
|
{
|
|
Operand dest = node.GetDestination(i);
|
|
|
|
if (dest.Kind == OperandKind.LocalVariable && !IsVisited(dest))
|
|
{
|
|
dest.NumberLocal(_intervals.Count);
|
|
|
|
_intervals.Add(new LiveInterval(dest));
|
|
|
|
SetVisited(dest);
|
|
}
|
|
}
|
|
}
|
|
|
|
_operationsCount += block.Operations.Count * InstructionGap;
|
|
|
|
if (block.Operations.Count == 0)
|
|
{
|
|
// Pretend we have a dummy instruction on the empty block.
|
|
_operationNodes.Add((default, default));
|
|
|
|
_operationsCount += InstructionGap;
|
|
}
|
|
}
|
|
|
|
_parentIntervals = _intervals.ToArray();
|
|
}
|
|
|
|
private void BuildIntervals(ControlFlowGraph cfg, AllocationContext context)
|
|
{
|
|
_blockRanges = new LiveRange[cfg.Blocks.Count];
|
|
|
|
int mapSize = _intervals.Count;
|
|
|
|
BitMap[] blkLiveGen = new BitMap[cfg.Blocks.Count];
|
|
BitMap[] blkLiveKill = new BitMap[cfg.Blocks.Count];
|
|
|
|
// Compute local live sets.
|
|
for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
|
|
{
|
|
BitMap liveGen = new BitMap(Allocators.Default, mapSize);
|
|
BitMap liveKill = new BitMap(Allocators.Default, mapSize);
|
|
|
|
for (Operation node = block.Operations.First; node != default; node = node.ListNext)
|
|
{
|
|
for (int i = 0; i < node.SourcesCount; i++)
|
|
{
|
|
VisitSource(node.GetSource(i));
|
|
}
|
|
|
|
for (int i = 0; i < node.DestinationsCount; i++)
|
|
{
|
|
VisitDestination(node.GetDestination(i));
|
|
}
|
|
|
|
void VisitSource(Operand source)
|
|
{
|
|
if (IsLocalOrRegister(source.Kind))
|
|
{
|
|
int id = GetOperandId(source);
|
|
|
|
if (!liveKill.IsSet(id))
|
|
{
|
|
liveGen.Set(id);
|
|
}
|
|
}
|
|
else if (source.Kind == OperandKind.Memory)
|
|
{
|
|
MemoryOperand memOp = source.GetMemory();
|
|
|
|
if (memOp.BaseAddress != default)
|
|
{
|
|
VisitSource(memOp.BaseAddress);
|
|
}
|
|
|
|
if (memOp.Index != default)
|
|
{
|
|
VisitSource(memOp.Index);
|
|
}
|
|
}
|
|
}
|
|
|
|
void VisitDestination(Operand dest)
|
|
{
|
|
liveKill.Set(GetOperandId(dest));
|
|
}
|
|
}
|
|
|
|
blkLiveGen [block.Index] = liveGen;
|
|
blkLiveKill[block.Index] = liveKill;
|
|
}
|
|
|
|
// Compute global live sets.
|
|
BitMap[] blkLiveIn = new BitMap[cfg.Blocks.Count];
|
|
BitMap[] blkLiveOut = new BitMap[cfg.Blocks.Count];
|
|
|
|
for (int index = 0; index < cfg.Blocks.Count; index++)
|
|
{
|
|
blkLiveIn [index] = new BitMap(Allocators.Default, mapSize);
|
|
blkLiveOut[index] = new BitMap(Allocators.Default, mapSize);
|
|
}
|
|
|
|
bool modified;
|
|
|
|
do
|
|
{
|
|
modified = false;
|
|
|
|
for (int index = 0; index < cfg.PostOrderBlocks.Length; index++)
|
|
{
|
|
BasicBlock block = cfg.PostOrderBlocks[index];
|
|
|
|
BitMap liveOut = blkLiveOut[block.Index];
|
|
|
|
for (int i = 0; i < block.SuccessorsCount; i++)
|
|
{
|
|
BasicBlock succ = block.GetSuccessor(i);
|
|
|
|
modified |= liveOut.Set(blkLiveIn[succ.Index]);
|
|
}
|
|
|
|
BitMap liveIn = blkLiveIn[block.Index];
|
|
|
|
liveIn.Set (liveOut);
|
|
liveIn.Clear(blkLiveKill[block.Index]);
|
|
liveIn.Set (blkLiveGen [block.Index]);
|
|
}
|
|
}
|
|
while (modified);
|
|
|
|
_blockLiveIn = blkLiveIn;
|
|
|
|
_blockEdges = new HashSet<int>();
|
|
|
|
// Compute lifetime intervals.
|
|
int operationPos = _operationsCount;
|
|
|
|
for (int index = 0; index < cfg.PostOrderBlocks.Length; index++)
|
|
{
|
|
BasicBlock block = cfg.PostOrderBlocks[index];
|
|
|
|
// We handle empty blocks by pretending they have a dummy instruction,
|
|
// because otherwise the block would have the same start and end position,
|
|
// and this is not valid.
|
|
int instCount = Math.Max(block.Operations.Count, 1);
|
|
|
|
int blockStart = operationPos - instCount * InstructionGap;
|
|
int blockEnd = operationPos;
|
|
|
|
_blockRanges[block.Index] = new LiveRange(blockStart, blockEnd);
|
|
|
|
_blockEdges.Add(blockStart);
|
|
|
|
BitMap liveOut = blkLiveOut[block.Index];
|
|
|
|
foreach (int id in liveOut)
|
|
{
|
|
_intervals[id].AddRange(blockStart, blockEnd);
|
|
}
|
|
|
|
if (block.Operations.Count == 0)
|
|
{
|
|
operationPos -= InstructionGap;
|
|
|
|
continue;
|
|
}
|
|
|
|
for (Operation node = block.Operations.Last; node != default; node = node.ListPrevious)
|
|
{
|
|
operationPos -= InstructionGap;
|
|
|
|
for (int i = 0; i < node.DestinationsCount; i++)
|
|
{
|
|
VisitDestination(node.GetDestination(i));
|
|
}
|
|
|
|
for (int i = 0; i < node.SourcesCount; i++)
|
|
{
|
|
VisitSource(node.GetSource(i));
|
|
}
|
|
|
|
if (node.Instruction == Instruction.Call)
|
|
{
|
|
AddIntervalCallerSavedReg(context.Masks.IntCallerSavedRegisters, operationPos, RegisterType.Integer);
|
|
AddIntervalCallerSavedReg(context.Masks.VecCallerSavedRegisters, operationPos, RegisterType.Vector);
|
|
}
|
|
|
|
void VisitSource(Operand source)
|
|
{
|
|
if (IsLocalOrRegister(source.Kind))
|
|
{
|
|
LiveInterval interval = _intervals[GetOperandId(source)];
|
|
|
|
interval.AddRange(blockStart, operationPos + 1);
|
|
interval.AddUsePosition(operationPos);
|
|
}
|
|
else if (source.Kind == OperandKind.Memory)
|
|
{
|
|
MemoryOperand memOp = source.GetMemory();
|
|
|
|
if (memOp.BaseAddress != default)
|
|
{
|
|
VisitSource(memOp.BaseAddress);
|
|
}
|
|
|
|
if (memOp.Index != default)
|
|
{
|
|
VisitSource(memOp.Index);
|
|
}
|
|
}
|
|
}
|
|
|
|
void VisitDestination(Operand dest)
|
|
{
|
|
LiveInterval interval = _intervals[GetOperandId(dest)];
|
|
|
|
interval.SetStart(operationPos + 1);
|
|
interval.AddUsePosition(operationPos + 1);
|
|
}
|
|
}
|
|
}
|
|
|
|
foreach (LiveInterval interval in _parentIntervals)
|
|
{
|
|
interval.Reset();
|
|
}
|
|
}
|
|
|
|
private void AddIntervalCallerSavedReg(int mask, int operationPos, RegisterType regType)
|
|
{
|
|
while (mask != 0)
|
|
{
|
|
int regIndex = BitOperations.TrailingZeroCount(mask);
|
|
|
|
Register callerSavedReg = new Register(regIndex, regType);
|
|
|
|
LiveInterval interval = _intervals[GetRegisterId(callerSavedReg)];
|
|
|
|
interval.AddRange(operationPos + 1, operationPos + InstructionGap);
|
|
|
|
mask &= ~(1 << regIndex);
|
|
}
|
|
}
|
|
|
|
private static int GetOperandId(Operand operand)
|
|
{
|
|
if (operand.Kind == OperandKind.LocalVariable)
|
|
{
|
|
return operand.GetLocalNumber();
|
|
}
|
|
else if (operand.Kind == OperandKind.Register)
|
|
{
|
|
return GetRegisterId(operand.GetRegister());
|
|
}
|
|
else
|
|
{
|
|
throw new ArgumentException($"Invalid operand kind \"{operand.Kind}\".");
|
|
}
|
|
}
|
|
|
|
private static int GetRegisterId(Register register)
|
|
{
|
|
return (register.Index << 1) | (register.Type == RegisterType.Vector ? 1 : 0);
|
|
}
|
|
|
|
private static bool IsLocalOrRegister(OperandKind kind)
|
|
{
|
|
return kind == OperandKind.LocalVariable ||
|
|
kind == OperandKind.Register;
|
|
}
|
|
}
|
|
} |