Reduce JIT GC allocations (#2515)

* Turn `MemoryOperand` into a struct

* Remove `IntrinsicOperation`

* Remove `PhiNode`

* Remove `Node`

* Turn `Operand` into a struct

* Turn `Operation` into a struct

* Clean up pool management methods

* Add `Arena` allocator

* Move `OperationHelper` to `Operation.Factory`

* Move `OperandHelper` to `Operand.Factory`

* Optimize `Operation` a bit

* Fix `Arena` initialization

* Rename `NativeList<T>` to `ArenaList<T>`

* Reduce `Operand` size from 88 to 56 bytes

* Reduce `Operation` size from 56 to 40 bytes

* Add optimistic interning of Register & Constant operands

* Optimize `RegisterUsage` pass a bit

* Optimize `RemoveUnusedNodes` pass a bit

Iterating in reverse-order allows killing dependency chains in a single
pass.

* Fix PPTC symbols

* Optimize `BasicBlock` a bit

Reduce allocations from `_successor` & `DominanceFrontiers`

* Fix `Operation` resize

* Make `Arena` expandable

Change the arena allocator to be expandable by allocating in pages, with
some of them being pooled. Currently 32 pages are pooled. An LRU removal
mechanism should probably be added to it.

Apparently MHR can allocate bitmaps large enough to exceed the 16MB
limit for the type.

* Move `Arena` & `ArenaList` to `Common`

* Remove `ThreadStaticPool` & co

* Add `PhiOperation`

* Reduce `Operand` size from 56 from 48 bytes

* Add linear-probing to `Operand` intern table

* Optimize `HybridAllocator` a bit

* Add `Allocators` class

* Tune `ArenaAllocator` sizes

* Add page removal mechanism to `ArenaAllocator`

Remove pages which have not been used for more than 5s after each reset.

I am on fence if this would be better using a Gen2 callback object like
the one in System.Buffers.ArrayPool<T>, to trim the pool. Because right
now if a large translation happens, the pages will be freed only after a
reset. This reset may not happen for a while because no new translation
is hit, but the arena base sizes are rather small.

* Fix `OOM` when allocating larger than page size in `ArenaAllocator`

Tweak resizing mechanism for Operand.Uses and Assignemnts.

* Optimize `Optimizer` a bit

* Optimize `Operand.Add<T>/Remove<T>` a bit

* Clean up `PreAllocator`

* Fix phi insertion order

Reduce codegen diffs.

* Fix code alignment

* Use new heuristics for degree of parallelism

* Suppress warnings

* Address gdkchan's feedback

Renamed `GetValue()` to `GetValueUnsafe()` to make it more clear that
`Operand.Value` should usually not be modified directly.

* Add fast path to `ArenaAllocator`

* Assembly for `ArenaAllocator.Allocate(ulong)`:

  .L0:
    mov rax, [rcx+0x18]
    lea r8, [rax+rdx]
    cmp r8, [rcx+0x10]
    ja short .L2
  .L1:
    mov rdx, [rcx+8]
    add rax, [rdx+8]
    mov [rcx+0x18], r8
    ret
  .L2:
    jmp ArenaAllocator.AllocateSlow(UInt64)

  A few variable/field had to be changed to ulong so that RyuJIT avoids
  emitting zero-extends.

* Implement a new heuristic to free pooled pages.

  If an arena is used often, it is more likely that its pages will be
  needed, so the pages are kept for longer (e.g: during PPTC rebuild or
  burst sof compilations). If is not used often, then it is more likely
  that its pages will not be needed (e.g: after PPTC rebuild or bursts
  of compilations).

* Address riperiperi's feedback

* Use `EqualityComparer<T>` in `IntrusiveList<T>`

Avoids a potential GC hole in `Equals(T, T)`.

1 files changed, 0 insertions, 309 deletions

diff --git a/ARMeilleure/IntermediateRepresentation/Node.cs b/ARMeilleure/IntermediateRepresentation/Node.cs
deleted file mode 100644
index 3f41d814..00000000
--- a/ARMeilleure/IntermediateRepresentation/Node.cs
+++ /dev/null
@@ -1,309 +0,0 @@
-using System;
-using System.Collections.Generic;
-
-namespace ARMeilleure.IntermediateRepresentation
-{
-    class Node : IIntrusiveListNode<Node>
-    {
-        public Node ListPrevious { get; set; }
-        public Node ListNext { get; set; }
-
-        public Operand Destination
-        {
-            get => _destinations.Count != 0 ? GetDestination(0) : null;
-            set => SetDestination(value);
-        }
-
-        private readonly List<Operand> _destinations;
-        private readonly List<Operand> _sources;
-        private bool _clearedDest;
-
-        public int DestinationsCount => _destinations.Count;
-        public int SourcesCount      => _sources.Count;
-
-        private void Resize(List<Operand> list, int size)
-        {
-            if (list.Count > size)
-            {
-                list.RemoveRange(size, list.Count - size);
-            } 
-            else
-            {
-                while (list.Count < size)
-                {
-                    list.Add(null);
-                }
-            }
-        }
-
-        public Node()
-        {
-            _destinations = new List<Operand>();
-            _sources = new List<Operand>();
-        }
-
-        public Node(Operand destination, int sourcesCount) : this()
-        {
-            Destination = destination;
-
-            Resize(_sources, sourcesCount);
-        }
-
-        private void Reset(int sourcesCount)
-        {
-            _clearedDest = true;
-            _sources.Clear();
-            ListPrevious = null;
-            ListNext = null;
-
-            Resize(_sources, sourcesCount);
-        }
-
-        public Node With(Operand destination, int sourcesCount)
-        {
-            Reset(sourcesCount);
-            Destination = destination;
-
-            return this;
-        }
-
-        public Node With(Operand[] destinations, int sourcesCount)
-        {
-            Reset(sourcesCount);
-            SetDestinations(destinations ?? throw new ArgumentNullException(nameof(destinations)));
-
-            return this;
-        }
-
-        public Operand GetDestination(int index)
-        {
-            return _destinations[index];
-        }
-
-        public Operand GetSource(int index)
-        {
-            return _sources[index];
-        }
-
-        public void SetDestination(int index, Operand destination)
-        {
-            if (!_clearedDest) 
-            {
-                RemoveAssignment(_destinations[index]);
-            }
-
-            AddAssignment(destination);
-
-            _clearedDest = false;
-
-            _destinations[index] = destination;
-        }
-
-        public void SetSource(int index, Operand source)
-        {
-            RemoveUse(_sources[index]);
-
-            AddUse(source);
-
-            _sources[index] = source;
-        }
-
-        private void RemoveOldDestinations()
-        {
-            if (!_clearedDest)
-            {
-                for (int index = 0; index < _destinations.Count; index++)
-                {
-                    RemoveAssignment(_destinations[index]);
-                }
-            }
-
-            _clearedDest = false;
-        }
-
-        public void SetDestination(Operand destination)
-        {
-            RemoveOldDestinations();
-
-            if (destination == null)
-            {
-                _destinations.Clear();
-                _clearedDest = true;
-            }
-            else
-            {
-                Resize(_destinations, 1);
-
-                _destinations[0] = destination;
-
-                AddAssignment(destination);
-            }
-        }
-
-        public void SetDestinations(Operand[] destinations)
-        {
-            RemoveOldDestinations();
-
-            Resize(_destinations, destinations.Length);
-
-            for (int index = 0; index < destinations.Length; index++)
-            {
-                Operand newOp = destinations[index];
-
-                _destinations[index] = newOp;
-
-                AddAssignment(newOp);
-            }
-        }
-
-        private void RemoveOldSources()
-        {
-            for (int index = 0; index < _sources.Count; index++)
-            {
-                RemoveUse(_sources[index]);
-            }
-        }
-
-        public void SetSource(Operand source)
-        {
-            RemoveOldSources();
-
-            if (source == null)
-            {
-                _sources.Clear();
-            }
-            else
-            {
-                Resize(_sources, 1);
-
-                _sources[0] = source;
-
-                AddUse(source);
-            }
-        }
-
-        public void SetSources(Operand[] sources)
-        {
-            RemoveOldSources();
-
-            Resize(_sources, sources.Length);
-
-            for (int index = 0; index < sources.Length; index++)
-            {
-                Operand newOp = sources[index];
-
-                _sources[index] = newOp;
-
-                AddUse(newOp);
-            }
-        }
-
-        private void AddAssignment(Operand op)
-        {
-            if (op == null)
-            {
-                return;
-            }
-
-            if (op.Kind == OperandKind.LocalVariable)
-            {
-                op.Assignments.Add(this);
-            }
-            else if (op.Kind == OperandKind.Memory)
-            {
-                MemoryOperand memOp = (MemoryOperand)op;
-
-                if (memOp.BaseAddress != null)
-                {
-                    memOp.BaseAddress.Assignments.Add(this);
-                }
-                
-                if (memOp.Index != null)
-                {
-                    memOp.Index.Assignments.Add(this);
-                }
-            }
-        }
-
-        private void RemoveAssignment(Operand op)
-        {
-            if (op == null)
-            {
-                return;
-            }
-
-            if (op.Kind == OperandKind.LocalVariable)
-            {
-                op.Assignments.Remove(this);
-            }
-            else if (op.Kind == OperandKind.Memory)
-            {
-                MemoryOperand memOp = (MemoryOperand)op;
-
-                if (memOp.BaseAddress != null)
-                {
-                    memOp.BaseAddress.Assignments.Remove(this);
-                }
-
-                if (memOp.Index != null)
-                {
-                    memOp.Index.Assignments.Remove(this);
-                }
-            }
-        }
-
-        private void AddUse(Operand op)
-        {
-            if (op == null)
-            {
-                return;
-            }
-
-            if (op.Kind == OperandKind.LocalVariable)
-            {
-                op.Uses.Add(this);
-            }
-            else if (op.Kind == OperandKind.Memory)
-            {
-                MemoryOperand memOp = (MemoryOperand)op;
-
-                if (memOp.BaseAddress != null)
-                {
-                    memOp.BaseAddress.Uses.Add(this);
-                }
-
-                if (memOp.Index != null)
-                {
-                    memOp.Index.Uses.Add(this);
-                }
-            }
-        }
-
-        private void RemoveUse(Operand op)
-        {
-            if (op == null)
-            {
-                return;
-            }
-
-            if (op.Kind == OperandKind.LocalVariable)
-            {
-                op.Uses.Remove(this);
-            }
-            else if (op.Kind == OperandKind.Memory)
-            {
-                MemoryOperand memOp = (MemoryOperand)op;
-
-                if (memOp.BaseAddress != null)
-                {
-                    memOp.BaseAddress.Uses.Remove(this);
-                }
-
-                if (memOp.Index != null)
-                {
-                    memOp.Index.Uses.Remove(this);
-                }
-            }
-        }
-    }
-}
\ No newline at end of file