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Optimize LSRA (#2563)

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* 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.
This commit is contained in:
FICTURE7 2021-10-09 01:15:44 +04:00 committed by GitHub
parent c54a14d0b8
commit 69093cf2d6
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GPG key ID: 4AEE18F83AFDEB23
9 changed files with 675 additions and 496 deletions
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4
ARMeilleure/Allocators.cs
View file

@ -10,11 +10,15 @@ namespace ARMeilleure
[ThreadStatic] private static ArenaAllocator _operands;
[ThreadStatic] private static ArenaAllocator _operations;
[ThreadStatic] private static ArenaAllocator _references;
[ThreadStatic] private static ArenaAllocator _liveRanges;
[ThreadStatic] private static ArenaAllocator _liveIntervals;
public static ArenaAllocator Default => GetAllocator(ref _default, 256 * 1024, 4);
public static ArenaAllocator Operands => GetAllocator(ref _operands, 64 * 1024, 8);
public static ArenaAllocator Operations => GetAllocator(ref _operations, 64 * 1024, 8);
public static ArenaAllocator References => GetAllocator(ref _references, 64 * 1024, 8);
public static ArenaAllocator LiveRanges => GetAllocator(ref _liveRanges, 64 * 1024, 8);
public static ArenaAllocator LiveIntervals => GetAllocator(ref _liveIntervals, 64 * 1024, 8);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static ArenaAllocator GetAllocator(ref ArenaAllocator alloc, uint pageSize, uint pageCount)

43
ARMeilleure/CodeGen/RegisterAllocators/CopyResolver.cs
View file

@ -1,6 +1,7 @@
using ARMeilleure.IntermediateRepresentation;
using System;
using System.Collections.Generic;
using static ARMeilleure.IntermediateRepresentation.Operand.Factory;
using static ARMeilleure.IntermediateRepresentation.Operation.Factory;
@ -25,7 +26,7 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
}
}
private List<Copy> _copies;
private readonly List<Copy> _copies;
public int Count => _copies.Count;
@ -146,21 +147,12 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
}
}
private Queue<Operation> _fillQueue = new Queue<Operation>();
private Queue<Operation> _spillQueue = new Queue<Operation>();
private ParallelCopy _parallelCopy;
private Queue<Operation> _fillQueue = null;
private Queue<Operation> _spillQueue = null;
private ParallelCopy _parallelCopy = null;
public bool HasCopy { get; private set; }
public CopyResolver()
{
_fillQueue = new Queue<Operation>();
_spillQueue = new Queue<Operation>();
_parallelCopy = new ParallelCopy();
}
public void AddSplit(LiveInterval left, LiveInterval right)
{
if (left.Local != right.Local)
@ -194,8 +186,12 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
private void AddSplitFill(LiveInterval left, LiveInterval right, OperandType type)
{
Operand register = GetRegister(right.Register, type);
if (_fillQueue == null)
{
_fillQueue = new Queue<Operation>();
}
Operand register = GetRegister(right.Register, type);
Operand offset = Const(left.SpillOffset);
_fillQueue.Enqueue(Operation(Instruction.Fill, register, offset));
@ -205,8 +201,12 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
private void AddSplitSpill(LiveInterval left, LiveInterval right, OperandType type)
{
Operand offset = Const(right.SpillOffset);
if (_spillQueue == null)
{
_spillQueue = new Queue<Operation>();
}
Operand offset = Const(right.SpillOffset);
Operand register = GetRegister(left.Register, type);
_spillQueue.Enqueue(Operation(Instruction.Spill, default, offset, register));
@ -216,6 +216,11 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
private void AddSplitCopy(LiveInterval left, LiveInterval right, OperandType type)
{
if (_parallelCopy == null)
{
_parallelCopy = new ParallelCopy();
}
_parallelCopy.AddCopy(right.Register, left.Register, type);
HasCopy = true;
@ -225,17 +230,23 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
{
List<Operation> sequence = new List<Operation>();
if (_spillQueue != null)
{
while (_spillQueue.TryDequeue(out Operation spillOp))
{
sequence.Add(spillOp);
}
}
_parallelCopy.Sequence(sequence);
_parallelCopy?.Sequence(sequence);
if (_fillQueue != null)
{
while (_fillQueue.TryDequeue(out Operation fillOp))
{
sequence.Add(fillOp);
}
}
return sequence.ToArray();
}

372
ARMeilleure/CodeGen/RegisterAllocators/LinearScanAllocator.cs
View file

@ -20,17 +20,13 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
private const int RegistersCount = 16;
private HashSet<int> _blockEdges;
private LiveRange[] _blockRanges;
private BitMap[] _blockLiveIn;
private List<LiveInterval> _intervals;
private LiveInterval[] _parentIntervals;
private List<(IntrusiveList<Operation>, Operation)> _operationNodes;
private int _operationsCount;
private class AllocationContext
@ -45,6 +41,11 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
public int IntUsedRegisters { get; set; }
public int VecUsedRegisters { get; set; }
private readonly int[] _intFreePositions;
private readonly int[] _vecFreePositions;
private readonly int _intFreePositionsCount;
private readonly int _vecFreePositionsCount;
public AllocationContext(StackAllocator stackAlloc, RegisterMasks masks, int intervalsCount)
{
StackAlloc = stackAlloc;
@ -52,6 +53,43 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
Active = new BitMap(Allocators.Default, intervalsCount);
Inactive = new BitMap(Allocators.Default, intervalsCount);
PopulateFreePositions(RegisterType.Integer, out _intFreePositions, out _intFreePositionsCount);
PopulateFreePositions(RegisterType.Vector, out _vecFreePositions, out _vecFreePositionsCount);
void PopulateFreePositions(RegisterType type, out int[] positions, out int count)
{
positions = new int[RegistersCount];
count = BitOperations.PopCount((uint)masks.GetAvailableRegisters(type));
int mask = masks.GetAvailableRegisters(type);
for (int i = 0; i < positions.Length; i++)
{
if ((mask & (1 << i)) != 0)
{
positions[i] = int.MaxValue;
}
}
}
}
public void GetFreePositions(RegisterType type, in Span<int> positions, out int count)
{
if (type == RegisterType.Integer)
{
_intFreePositions.CopyTo(positions);
count = _intFreePositionsCount;
}
else
{
Debug.Assert(type == RegisterType.Vector);
_vecFreePositions.CopyTo(positions);
count = _vecFreePositionsCount;
}
}
public void MoveActiveToInactive(int bit)
@ -132,6 +170,8 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
{
LiveInterval interval = _intervals[iIndex];
interval.Forward(current.GetStart());
if (interval.GetEnd() < current.GetStart())
{
context.Active.Clear(iIndex);
@ -147,6 +187,8 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
{
LiveInterval interval = _intervals[iIndex];
interval.Forward(current.GetStart());
if (interval.GetEnd() < current.GetStart())
{
context.Inactive.Clear(iIndex);
@ -167,45 +209,48 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
{
RegisterType regType = current.Local.Type.ToRegisterType();
int availableRegisters = context.Masks.GetAvailableRegisters(regType);
Span<int> freePositions = stackalloc int[RegistersCount];
int[] freePositions = new int[RegistersCount];
for (int index = 0; index < RegistersCount; index++)
{
if ((availableRegisters & (1 << index)) != 0)
{
freePositions[index] = int.MaxValue;
}
}
context.GetFreePositions(regType, freePositions, out int freePositionsCount);
foreach (int iIndex in context.Active)
{
LiveInterval interval = _intervals[iIndex];
Register reg = interval.Register;
if (interval.Register.Type == regType)
if (reg.Type == regType)
{
freePositions[interval.Register.Index] = 0;
freePositions[reg.Index] = 0;
freePositionsCount--;
}
}
// If all registers are already active, return early. No point in inspecting the inactive set to look for
// holes.
if (freePositionsCount == 0)
{
return false;
}
foreach (int iIndex in context.Inactive)
{
LiveInterval interval = _intervals[iIndex];
Register reg = interval.Register;
if (interval.Register.Type == regType)
ref int freePosition = ref freePositions[reg.Index];
if (reg.Type == regType && freePosition != 0)
{
int overlapPosition = interval.GetOverlapPosition(current);
if (overlapPosition != LiveInterval.NotFound && freePositions[interval.Register.Index] > overlapPosition)
if (overlapPosition != LiveInterval.NotFound && freePosition > overlapPosition)
{
freePositions[interval.Register.Index] = overlapPosition;
freePosition = overlapPosition;
}
}
}
int selectedReg = GetHighestValueIndex(freePositions);
int selectedNextUse = freePositions[selectedReg];
// Intervals starts and ends at odd positions, unless they span an entire
@ -227,8 +272,6 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
}
else if (selectedNextUse < current.GetEnd())
{
Debug.Assert(selectedNextUse > current.GetStart(), "Trying to split interval at the start.");
LiveInterval splitChild = current.Split(selectedNextUse);
if (splitChild.UsesCount != 0)
@ -263,44 +306,35 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
{
RegisterType regType = current.Local.Type.ToRegisterType();
int availableRegisters = context.Masks.GetAvailableRegisters(regType);
Span<int> usePositions = stackalloc int[RegistersCount];
Span<int> blockedPositions = stackalloc int[RegistersCount];
int[] usePositions = new int[RegistersCount];
int[] blockedPositions = new int[RegistersCount];
for (int index = 0; index < RegistersCount; index++)
{
if ((availableRegisters & (1 << index)) != 0)
{
usePositions[index] = int.MaxValue;
blockedPositions[index] = int.MaxValue;
}
}
void SetUsePosition(int index, int position)
{
usePositions[index] = Math.Min(usePositions[index], position);
}
void SetBlockedPosition(int index, int position)
{
blockedPositions[index] = Math.Min(blockedPositions[index], position);
SetUsePosition(index, position);
}
context.GetFreePositions(regType, usePositions, out _);
context.GetFreePositions(regType, blockedPositions, out _);
foreach (int iIndex in context.Active)
{
LiveInterval interval = _intervals[iIndex];
Register reg = interval.Register;
if (!interval.IsFixed && interval.Register.Type == regType)
if (reg.Type == regType)
{
ref int usePosition = ref usePositions[reg.Index];
ref int blockedPosition = ref blockedPositions[reg.Index];
if (interval.IsFixed)
{
usePosition = 0;
blockedPosition = 0;
}
else
{
int nextUse = interval.NextUseAfter(current.GetStart());
if (nextUse != -1)
if (nextUse != LiveInterval.NotFound && usePosition > nextUse)
{
SetUsePosition(interval.Register.Index, nextUse);
usePosition = nextUse;
}
}
}
}
@ -308,45 +342,36 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
foreach (int iIndex in context.Inactive)
{
LiveInterval interval = _intervals[iIndex];
Register reg = interval.Register;
if (!interval.IsFixed && interval.Register.Type == regType && interval.Overlaps(current))
if (reg.Type == regType)
{
int nextUse = interval.NextUseAfter(current.GetStart());
ref int usePosition = ref usePositions[reg.Index];
ref int blockedPosition = ref blockedPositions[reg.Index];
if (nextUse != -1)
{
SetUsePosition(interval.Register.Index, nextUse);
}
}
}
foreach (int iIndex in context.Active)
{
LiveInterval interval = _intervals[iIndex];
if (interval.IsFixed && interval.Register.Type == regType)
{
SetBlockedPosition(interval.Register.Index, 0);
}
}
foreach (int iIndex in context.Inactive)
{
LiveInterval interval = _intervals[iIndex];
if (interval.IsFixed && interval.Register.Type == regType)
if (interval.IsFixed)
{
int overlapPosition = interval.GetOverlapPosition(current);
if (overlapPosition != LiveInterval.NotFound)
{
SetBlockedPosition(interval.Register.Index, overlapPosition);
blockedPosition = Math.Min(blockedPosition, overlapPosition);
usePosition = Math.Min(usePosition, overlapPosition);
}
}
else if (interval.Overlaps(current))
{
int nextUse = interval.NextUseAfter(current.GetStart());
if (nextUse != LiveInterval.NotFound && usePosition > nextUse)
{
usePosition = nextUse;
}
}
}
}
int selectedReg = GetHighestValueIndex(usePositions);
int currentFirstUse = current.FirstUse();
Debug.Assert(currentFirstUse >= 0, "Current interval has no uses.");
@ -405,24 +430,24 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
}
}
private static int GetHighestValueIndex(int[] array)
private static int GetHighestValueIndex(Span<int> span)
{
int higuest = array[0];
int highest = span[0];
if (higuest == int.MaxValue)
if (highest == int.MaxValue)
{
return 0;
}
int selected = 0;
for (int index = 1; index < array.Length; index++)
for (int index = 1; index < span.Length; index++)
{
int current = array[index];
int current = span[index];
if (higuest < current)
if (highest < current)
{
higuest = current;
highest = current;
selected = index;
if (current == int.MaxValue)
@ -543,21 +568,21 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
CopyResolver GetCopyResolver(int position)
{
CopyResolver copyResolver = new CopyResolver();
if (copyResolvers.TryAdd(position, copyResolver))
if (!copyResolvers.TryGetValue(position, out CopyResolver copyResolver))
{
return copyResolver;
copyResolver = new CopyResolver();
copyResolvers.Add(position, copyResolver);
}
return copyResolvers[position];
return copyResolver;
}
foreach (LiveInterval interval in _intervals.Where(x => x.IsSplit))
{
LiveInterval previous = interval;
foreach (LiveInterval splitChild in interval.SplitChilds())
foreach (LiveInterval splitChild in interval.SplitChildren())
{
int splitPosition = splitChild.GetStart();
@ -607,6 +632,12 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
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))
@ -629,7 +660,7 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
succIndex = successor.GetSuccessor(0).Index;
}
CopyResolver copyResolver = new CopyResolver();
CopyResolver copyResolver = null;
foreach (int iIndex in _blockLiveIn[succIndex])
{
@ -646,13 +677,18 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
LiveInterval left = interval.GetSplitChild(lEnd);
LiveInterval right = interval.GetSplitChild(rStart);
if (left != null && right != null && left != right)
if (left != default && right != default && left != right)
{
if (copyResolver == null)
{
copyResolver = new CopyResolver();
}
copyResolver.AddSplit(left, right);
}
}
if (!copyResolver.HasCopy)
if (copyResolver == null || !copyResolver.HasCopy)
{
continue;
}
@ -699,10 +735,8 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
{
Operand register = GetRegister(current);
IList<int> usePositions = current.UsePositions();
for (int i = usePositions.Count - 1; i >= 0; i--)
foreach (int usePosition in current.UsePositions())
{
int usePosition = -usePositions[i];
(_, Operation operation) = GetOperationNode(usePosition);
for (int index = 0; index < operation.SourcesCount; index++)
@ -759,7 +793,6 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
private void NumberLocals(ControlFlowGraph cfg)
{
_operationNodes = new List<(IntrusiveList<Operation>, Operation)>();
_intervals = new List<LiveInterval>();
for (int index = 0; index < RegistersCount; index++)
@ -768,7 +801,18 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
_intervals.Add(new LiveInterval(new Register(index, RegisterType.Vector)));
}
HashSet<Operand> visited = new HashSet<Operand>();
// 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;
@ -784,11 +828,13 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
{
Operand dest = node.GetDestination(i);
if (dest.Kind == OperandKind.LocalVariable && visited.Add(dest))
if (dest.Kind == OperandKind.LocalVariable && !IsVisited(dest))
{
dest.NumberLocal(_intervals.Count);
_intervals.Add(new LiveInterval(dest));
SetVisited(dest);
}
}
}
@ -824,7 +870,19 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
for (Operation node = block.Operations.First; node != default; node = node.ListNext)
{
Sources(node, (source) =>
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);
@ -832,11 +890,25 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
{
liveGen.Set(id);
}
});
for (int i = 0; i < node.DestinationsCount; i++)
}
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)
{
Operand dest = node.GetDestination(i);
liveKill.Set(GetOperandId(dest));
}
}
@ -920,33 +992,64 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
continue;
}
foreach (Operation node in BottomOperations(block))
for (Operation node = block.Operations.Last; node != default; node = node.ListPrevious)
{
operationPos -= InstructionGap;
for (int i = 0; i < node.DestinationsCount; i++)
{
Operand dest = node.GetDestination(i);
LiveInterval interval = _intervals[GetOperandId(dest)];
interval.SetStart(operationPos + 1);
interval.AddUsePosition(operationPos + 1);
VisitDestination(node.GetDestination(i));
}
Sources(node, (source) =>
for (int i = 0; i < node.SourcesCount; i++)
{
LiveInterval interval = _intervals[GetOperandId(source)];
interval.AddRange(blockStart, operationPos + 1);
interval.AddUsePosition(operationPos);
});
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();
}
}
@ -987,45 +1090,6 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
return (register.Index << 1) | (register.Type == RegisterType.Vector ? 1 : 0);
}
private static IEnumerable<Operation> BottomOperations(BasicBlock block)
{
Operation node = block.Operations.Last;
while (node != default)
{
yield return node;
node = node.ListPrevious;
}
}
private static void Sources(Operation node, Action<Operand> action)
{
for (int index = 0; index < node.SourcesCount; index++)
{
Operand source = node.GetSource(index);
if (IsLocalOrRegister(source.Kind))
{
action(source);
}
else if (source.Kind == OperandKind.Memory)
{
MemoryOperand memOp = source.GetMemory();
if (memOp.BaseAddress != default)
{
action(memOp.BaseAddress);
}
if (memOp.Index != default)
{
action(memOp.Index);
}
}
}
}
private static bool IsLocalOrRegister(OperandKind kind)
{
return kind == OperandKind.LocalVariable ||

444
ARMeilleure/CodeGen/RegisterAllocators/LiveInterval.cs
View file

@ -1,341 +1,291 @@
using ARMeilleure.Common;
using ARMeilleure.IntermediateRepresentation;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
namespace ARMeilleure.CodeGen.RegisterAllocators
{
class LiveInterval : IComparable<LiveInterval>
unsafe readonly struct LiveInterval : IComparable<LiveInterval>
{
public const int NotFound = -1;
private LiveInterval _parent;
private SortedIntegerList _usePositions;
public int UsesCount => _usePositions.Count;
private List<LiveRange> _ranges;
private SortedList<int, LiveInterval> _childs;
public bool IsSplit => _childs.Count != 0;
public Operand Local { get; }
public Register Register { get; set; }
public int SpillOffset { get; private set; }
public bool IsSpilled => SpillOffset != -1;
public bool IsFixed { get; }
public bool IsEmpty => _ranges.Count == 0;
public LiveInterval(Operand local = default, LiveInterval parent = null)
private struct Data
{
Local = local;
_parent = parent ?? this;
public int End;
public int SpillOffset;
_usePositions = new SortedIntegerList();
public LiveRange FirstRange;
public LiveRange PrevRange;
public LiveRange CurrRange;
_ranges = new List<LiveRange>();
public LiveInterval Parent;
_childs = new SortedList<int, LiveInterval>();
public UseList Uses;
public LiveIntervalList Children;
public Operand Local;
public Register Register;
public bool IsFixed;
}
private readonly Data* _data;
private ref int End => ref _data->End;
private ref LiveRange FirstRange => ref _data->FirstRange;
private ref LiveRange CurrRange => ref _data->CurrRange;
private ref LiveRange PrevRange => ref _data->PrevRange;
private ref LiveInterval Parent => ref _data->Parent;
private ref UseList Uses => ref _data->Uses;
private ref LiveIntervalList Children => ref _data->Children;
public Operand Local => _data->Local;
public ref Register Register => ref _data->Register;
public ref int SpillOffset => ref _data->SpillOffset;
public bool IsFixed => _data->IsFixed;
public bool IsEmpty => FirstRange == default;
public bool IsSplit => Children.Count != 0;
public bool IsSpilled => SpillOffset != -1;
public int UsesCount => Uses.Count;
public LiveInterval(Operand local = default, LiveInterval parent = default)
{
_data = Allocators.LiveIntervals.Allocate<Data>();
*_data = default;
_data->IsFixed = false;
_data->Local = local;
Parent = parent == default ? this : parent;
Uses = new UseList();
Children = new LiveIntervalList();
FirstRange = default;
CurrRange = default;
PrevRange = default;
SpillOffset = -1;
}
public LiveInterval(Register register) : this()
public LiveInterval(Register register) : this(local: default, parent: default)
{
IsFixed = true;
_data->IsFixed = true;
Register = register;
}
public void SetStart(int position)
public void Reset()
{
if (_ranges.Count != 0)
{
Debug.Assert(position != _ranges[0].End);
PrevRange = default;
CurrRange = FirstRange;
}
_ranges[0] = new LiveRange(position, _ranges[0].End);
}
else
public void Forward(int position)
{
_ranges.Add(new LiveRange(position, position + 1));
LiveRange prev = PrevRange;
LiveRange curr = CurrRange;
while (curr != default && curr.Start < position && !curr.Overlaps(position))
{
prev = curr;
curr = curr.Next;
}
PrevRange = prev;
CurrRange = curr;
}
public int GetStart()
{
if (_ranges.Count == 0)
{
throw new InvalidOperationException("Empty interval.");
Debug.Assert(!IsEmpty, "Empty LiveInterval cannot have a start position.");
return FirstRange.Start;
}
return _ranges[0].Start;
}
public void SetEnd(int position)
public void SetStart(int position)
{
if (_ranges.Count != 0)
if (FirstRange != default)
{
int lastIdx = _ranges.Count - 1;
Debug.Assert(position != FirstRange.End);
Debug.Assert(position != _ranges[lastIdx].Start);
_ranges[lastIdx] = new LiveRange(_ranges[lastIdx].Start, position);
FirstRange.Start = position;
}
else
{
_ranges.Add(new LiveRange(position, position + 1));
FirstRange = new LiveRange(position, position + 1);
End = position + 1;
}
}
public int GetEnd()
{
if (_ranges.Count == 0)
{
throw new InvalidOperationException("Empty interval.");
}
Debug.Assert(!IsEmpty, "Empty LiveInterval cannot have an end position.");
return _ranges[_ranges.Count - 1].End;
return End;
}
public void AddRange(int start, int end)
{
if (start >= end)
Debug.Assert(start < end, $"Invalid range start position {start}, {end}");
if (FirstRange != default)
{
throw new ArgumentException("Invalid range start position " + start + ", " + end);
// If the new range ends exactly where the first range start, then coalesce together.
if (end == FirstRange.Start)
{
FirstRange.Start = start;
return;
}
int index = _ranges.BinarySearch(new LiveRange(start, end));
if (index >= 0)
// If the new range is already contained, then coalesce together.
else if (FirstRange.Overlaps(start, end))
{
// New range insersects with an existing range, we need to remove
// all the intersecting ranges before adding the new one.
// We also extend the new range as needed, based on the values of
// the existing ranges being removed.
int lIndex = index;
int rIndex = index;
FirstRange.Start = Math.Min(FirstRange.Start, start);
FirstRange.End = Math.Max(FirstRange.End, end);
End = Math.Max(End, end);
while (lIndex > 0 && _ranges[lIndex - 1].End >= start)
{
lIndex--;
}
while (rIndex + 1 < _ranges.Count && _ranges[rIndex + 1].Start <= end)
{
rIndex++;
}
if (start > _ranges[lIndex].Start)
{
start = _ranges[lIndex].Start;
}
if (end < _ranges[rIndex].End)
{
end = _ranges[rIndex].End;
}
_ranges.RemoveRange(lIndex, (rIndex - lIndex) + 1);
InsertRange(lIndex, start, end);
}
else
{
InsertRange(~index, start, end);
Debug.Assert(FirstRange.Next == default || !FirstRange.Overlaps(FirstRange.Next));
return;
}
}
private void InsertRange(int index, int start, int end)
{
// Here we insert a new range on the ranges list.
// If possible, we extend an existing range rather than inserting a new one.
// We can extend an existing range if any of the following conditions are true:
// - The new range starts right after the end of the previous range on the list.
// - The new range ends right before the start of the next range on the list.
// If both cases are true, we can extend either one. We prefer to extend the
// previous range, and then remove the next one, but theres no specific reason
// for that, extending either one will do.
int? extIndex = null;
FirstRange = new LiveRange(start, end, FirstRange);
End = Math.Max(End, end);
if (index > 0 && _ranges[index - 1].End == start)
{
start = _ranges[index - 1].Start;
extIndex = index - 1;
}
if (index < _ranges.Count && _ranges[index].Start == end)
{
end = _ranges[index].End;
if (extIndex.HasValue)
{
_ranges.RemoveAt(index);
}
else
{
extIndex = index;
}
}
if (extIndex.HasValue)
{
_ranges[extIndex.Value] = new LiveRange(start, end);
}
else
{
_ranges.Insert(index, new LiveRange(start, end));
}
Debug.Assert(FirstRange.Next == default || !FirstRange.Overlaps(FirstRange.Next));
}
public void AddUsePosition(int position)
{
// Inserts are in descending order, but ascending is faster for SortedIntegerList<>.
// We flip the ordering, then iterate backwards when using the final list.
_usePositions.Add(-position);
Uses.Add(position);
}
public bool Overlaps(int position)
{
return _ranges.BinarySearch(new LiveRange(position, position + 1)) >= 0;
}
LiveRange curr = CurrRange;
public bool Overlaps(LiveInterval other)
while (curr != default && curr.Start <= position)
{
foreach (LiveRange range in other._ranges)
{
if (_ranges.BinarySearch(range) >= 0)
if (curr.Overlaps(position))
{
return true;
}
curr = curr.Next;
}
return false;
}
public bool Overlaps(LiveInterval other)
{
return GetOverlapPosition(other) != NotFound;
}
public int GetOverlapPosition(LiveInterval other)
{
foreach (LiveRange range in other._ranges)
{
int overlapIndex = _ranges.BinarySearch(range);
LiveRange a = CurrRange;
LiveRange b = other.CurrRange;
if (overlapIndex >= 0)
while (a != default)
{
// It's possible that we have multiple overlaps within a single interval,
// in this case, we pick the one with the lowest start position, since
// we return the first overlap position.
while (overlapIndex > 0 && _ranges[overlapIndex - 1].End > range.Start)
while (b != default && b.Start < a.Start)
{
overlapIndex--;
if (a.Overlaps(b))
{
return a.Start;
}
LiveRange overlappingRange = _ranges[overlapIndex];
return overlappingRange.Start;
b = b.Next;
}
if (b == default)
{
break;
}
else if (a.Overlaps(b))
{
return a.Start;
}
a = a.Next;
}
return NotFound;
}
public IEnumerable<LiveInterval> SplitChilds()
public ReadOnlySpan<LiveInterval> SplitChildren()
{
return _childs.Values;
return Parent.Children.Span;
}
public IList<int> UsePositions()
public ReadOnlySpan<int> UsePositions()
{
return _usePositions.GetList();
return Uses.Span;
}
public int FirstUse()
{
if (_usePositions.Count == 0)
{
return NotFound;
}
return -_usePositions.Last();
return Uses.FirstUse;
}
public int NextUseAfter(int position)
{
int index = _usePositions.FindLessEqualIndex(-position);
return (index >= 0) ? -_usePositions[index] : NotFound;
}
public void RemoveAfter(int position)
{
int index = _usePositions.FindLessEqualIndex(-position);
_usePositions.RemoveRange(0, index + 1);
return Uses.NextUse(position);
}
public LiveInterval Split(int position)
{
LiveInterval right = new LiveInterval(Local, _parent);
LiveInterval result = new(Local, Parent);
result.End = End;
int splitIndex = 0;
LiveRange prev = PrevRange;
LiveRange curr = CurrRange;
for (; splitIndex < _ranges.Count; splitIndex++)
while (curr != default && curr.Start < position && !curr.Overlaps(position))
{
LiveRange range = _ranges[splitIndex];
if (position > range.Start && position < range.End)
{
right._ranges.Add(new LiveRange(position, range.End));
range = new LiveRange(range.Start, position);
_ranges[splitIndex++] = range;
break;
prev = curr;
curr = curr.Next;
}
if (range.Start >= position)
if (curr.Start >= position)
{
break;
}
}
prev.Next = default;
if (splitIndex < _ranges.Count)
result.FirstRange = curr;
End = prev.End;
}
else
{
int count = _ranges.Count - splitIndex;
result.FirstRange = new LiveRange(position, curr.End, curr.Next);
right._ranges.AddRange(_ranges.GetRange(splitIndex, count));
curr.End = position;
curr.Next = default;
_ranges.RemoveRange(splitIndex, count);
End = curr.End;
}
int addAfter = _usePositions.FindLessEqualIndex(-position);
for (int index = addAfter; index >= 0; index--)
{
int usePosition = _usePositions[index];
right._usePositions.Add(usePosition);
}
result.Uses = Uses.Split(position);
RemoveAfter(position);
AddSplitChild(result);
Debug.Assert(_ranges.Count != 0, "Left interval is empty after split.");
Debug.Assert(!IsEmpty, "Left interval is empty after split.");
Debug.Assert(!result.IsEmpty, "Right interval is empty after split.");
Debug.Assert(right._ranges.Count != 0, "Right interval is empty after split.");
// Make sure the iterator in the new split is pointing to the start.
result.Reset();
AddSplitChild(right);
return right;
return result;
}
private void AddSplitChild(LiveInterval child)
{
Debug.Assert(!child.IsEmpty, "Trying to insert a empty interval.");
Debug.Assert(!child.IsEmpty, "Trying to insert an empty interval.");
_parent._childs.Add(child.GetStart(), child);
Parent.Children.Add(child);
}
public LiveInterval GetSplitChild(int position)
@ -345,20 +295,24 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
return this;
}
foreach (LiveInterval splitChild in _childs.Values)
foreach (LiveInterval splitChild in SplitChildren())
{
if (splitChild.Overlaps(position))
{
return splitChild;
}
else if (splitChild.GetStart() > position)
{
break;
}
}
return null;
return default;
}
public bool TrySpillWithSiblingOffset()
{
foreach (LiveInterval splitChild in _parent._childs.Values)
foreach (LiveInterval splitChild in SplitChildren())
{
if (splitChild.IsSpilled)
{
@ -376,19 +330,65 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
SpillOffset = offset;
}
public int CompareTo(LiveInterval other)
public int CompareTo(LiveInterval interval)
{
if (_ranges.Count == 0 || other._ranges.Count == 0)
if (FirstRange == default || interval.FirstRange == default)
{
return _ranges.Count.CompareTo(other._ranges.Count);
return 0;
}
return _ranges[0].Start.CompareTo(other._ranges[0].Start);
return GetStart().CompareTo(interval.GetStart());
}
public bool Equals(LiveInterval interval)
{
return interval._data == _data;
}
public override bool Equals(object obj)
{
return obj is LiveInterval interval && Equals(interval);
}
public static bool operator ==(LiveInterval a, LiveInterval b)
{
return a.Equals(b);
}
public static bool operator !=(LiveInterval a, LiveInterval b)
{
return !a.Equals(b);
}
public override int GetHashCode()
{
return HashCode.Combine((IntPtr)_data);
}
public override string ToString()
{
return string.Join("; ", _ranges);
LiveInterval self = this;
IEnumerable<string> GetRanges()
{
LiveRange curr = self.CurrRange;
while (curr != default)
{
if (curr == self.CurrRange)
{
yield return "*" + curr;
}
else
{
yield return curr.ToString();
}
curr = curr.Next;
}
}
return string.Join(", ", GetRanges());
}
}
}

40
ARMeilleure/CodeGen/RegisterAllocators/LiveIntervalList.cs Normal file
View file

@ -0,0 +1,40 @@
using System;
namespace ARMeilleure.CodeGen.RegisterAllocators
{
unsafe struct LiveIntervalList
{
private LiveInterval* _items;
private int _count;
private int _capacity;
public int Count => _count;
public Span<LiveInterval> Span => new(_items, _count);
public void Add(LiveInterval interval)
{
if (_count + 1 > _capacity)
{
var oldSpan = Span;
_capacity = Math.Max(4, _capacity * 2);
_items = Allocators.References.Allocate<LiveInterval>((uint)_capacity);
var newSpan = Span;
oldSpan.CopyTo(newSpan);
}
int position = interval.GetStart();
int i = _count - 1;
while (i >= 0 && _items[i].GetStart() > position)
{
_items[i + 1] = _items[i--];
}
_items[i + 1] = interval;
_count++;
}
}
}

63
ARMeilleure/CodeGen/RegisterAllocators/LiveRange.cs
View file

@ -2,30 +2,73 @@ using System;
namespace ARMeilleure.CodeGen.RegisterAllocators
{
struct LiveRange : IComparable<LiveRange>
unsafe readonly struct LiveRange : IEquatable<LiveRange>
{
public int Start { get; }
public int End { get; }
private struct Data
{
public int Start;
public int End;
public LiveRange Next;
}
public LiveRange(int start, int end)
private readonly Data* _data;
public ref int Start => ref _data->Start;
public ref int End => ref _data->End;
public ref LiveRange Next => ref _data->Next;
public LiveRange(int start, int end, LiveRange next = default)
{
_data = Allocators.LiveRanges.Allocate<Data>();
Start = start;
End = end;
Next = next;
}
public int CompareTo(LiveRange other)
public bool Overlaps(int start, int end)
{
if (Start < other.End && other.Start < End)
{
return 0;
return Start < end && start < End;
}
return Start.CompareTo(other.Start);
public bool Overlaps(LiveRange range)
{
return Start < range.End && range.Start < End;
}
public bool Overlaps(int position)
{
return position >= Start && position < End;
}
public bool Equals(LiveRange range)
{
return range._data == _data;
}
public override bool Equals(object obj)
{
return obj is LiveRange range && Equals(range);
}
public static bool operator ==(LiveRange a, LiveRange b)
{
return a.Equals(b);
}
public static bool operator !=(LiveRange a, LiveRange b)
{
return !a.Equals(b);
}
public override int GetHashCode()
{
return HashCode.Combine((IntPtr)_data);
}
public override string ToString()
{
return $"[{Start}, {End}[";
return $"[{Start}, {End})";
}
}
}

84
ARMeilleure/CodeGen/RegisterAllocators/UseList.cs Normal file
View file

@ -0,0 +1,84 @@
using System;
namespace ARMeilleure.CodeGen.RegisterAllocators
{
unsafe struct UseList
{
private int* _items;
private int _capacity;
private int _count;
public int Count => _count;
public int FirstUse => _count > 0 ? _items[_count - 1] : LiveInterval.NotFound;
public Span<int> Span => new(_items, _count);
public void Add(int position)
{
if (_count + 1 > _capacity)
{
var oldSpan = Span;
_capacity = Math.Max(4, _capacity * 2);
_items = Allocators.Default.Allocate<int>((uint)_capacity);
var newSpan = Span;
oldSpan.CopyTo(newSpan);
}
// Use positions are usually inserted in descending order, so inserting in descending order is faster,
// since the number of half exchanges is reduced.
int i = _count - 1;
while (i >= 0 && _items[i] < position)
{
_items[i + 1] = _items[i--];
}
_items[i + 1] = position;
_count++;
}
public int NextUse(int position)
{
int index = NextUseIndex(position);
return index != LiveInterval.NotFound ? _items[index] : LiveInterval.NotFound;
}
public int NextUseIndex(int position)
{
int i = _count - 1;
if (i == -1 || position > _items[0])
{
return LiveInterval.NotFound;
}
while (i >= 0 && _items[i] < position)
{
i--;
}
return i;
}
public UseList Split(int position)
{
int index = NextUseIndex(position);
// Since the list is in descending order, the new split list takes the front of the list and the current
// list takes the back of the list.
UseList result = new();
result._count = index + 1;
result._capacity = result._count;
result._items = _items;
_count = _count - result._count;
_capacity = _count;
_items = _items + result._count;
return result;
}
}
}

14
ARMeilleure/Common/BitMap.cs
View file

@ -2,6 +2,7 @@ using System;
using System.Collections;
using System.Collections.Generic;
using System.Numerics;
using System.Runtime.CompilerServices;
namespace ARMeilleure.Common
{
@ -170,12 +171,12 @@ namespace ARMeilleure.Common
public struct Enumerator : IEnumerator<int>
{
private int _index;
private long _index;
private long _mask;
private int _bit;
private readonly BitMap _map;
public int Current => _index * IntSize + _bit;
public int Current => (int)_index * IntSize + _bit;
object IEnumerator.Current => Current;
public Enumerator(BitMap map)
@ -186,6 +187,7 @@ namespace ARMeilleure.Common
_map = map;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool MoveNext()
{
if (_mask != 0)
@ -193,14 +195,18 @@ namespace ARMeilleure.Common
_mask &= ~(1L << _bit);
}
// Manually hoist these loads, because RyuJIT does not.
long count = (uint)_map._count;
long* masks = _map._masks;
while (_mask == 0)
{
if (++_index >= _map._count)
if (++_index >= count)
{
return false;
}
_mask = _map._masks[_index];
_mask = masks[_index];
}
_bit = BitOperations.TrailingZeroCount(_mask);

73
ARMeilleure/Common/SortedIntegerList.cs
View file

@ -1,73 +0,0 @@
using System;
using System.Collections.Generic;
namespace ARMeilleure.Common
{
public class SortedIntegerList
{
private List<int> _items;
public int Count => _items.Count;
public int this[int index]
{
get
{
return _items[index];
}
set
{
_items[index] = value;
}
}
public SortedIntegerList()
{
_items = new List<int>();
}
public bool Add(int value)
{
if (_items.Count == 0 || value > Last())
{
_items.Add(value);
return true;
}
else
{
int index = _items.BinarySearch(value);
if (index >= 0)
{
return false;
}
_items.Insert(-1 - index, value);
return true;
}
}
public int FindLessEqualIndex(int value)
{
int index = _items.BinarySearch(value);
return (index < 0) ? (-2 - index) : index;
}
public void RemoveRange(int index, int count)
{
if (count > 0)
{
_items.RemoveRange(index, count);
}
}
public int Last()
{
return _items[Count - 1];
}
public List<int> GetList()
{
return _items;
}
}
}