From 61634dd415fb71b3ae85871a0873d00195b0900c Mon Sep 17 00:00:00 2001
From: gdkchan <gab.dark.100@gmail.com>
Date: Wed, 16 Dec 2020 17:07:42 -0300
Subject: Clear JIT cache on exit (#1518)

* Initial cache memory allocator implementation

* Get rid of CallFlag

* Perform cache cleanup on exit

* Basic cache invalidation

* Thats not how conditionals works in C# it seems

* Set PTC version to PR number

* Address PR feedback

* Update InstEmitFlowHelper.cs

* Flag clear on address is no longer needed

* Do not include exit block in function size calculation

* Dispose jump table

* For future use

* InternalVersion = 1519 (force retest).

Co-authored-by: LDj3SNuD <35856442+LDj3SNuD@users.noreply.github.com>
---
 .../Translation/Cache/CacheMemoryAllocator.cs      | 96 ++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 ARMeilleure/Translation/Cache/CacheMemoryAllocator.cs

(limited to 'ARMeilleure/Translation/Cache/CacheMemoryAllocator.cs')

diff --git a/ARMeilleure/Translation/Cache/CacheMemoryAllocator.cs b/ARMeilleure/Translation/Cache/CacheMemoryAllocator.cs
new file mode 100644
index 00000000..3111e886
--- /dev/null
+++ b/ARMeilleure/Translation/Cache/CacheMemoryAllocator.cs
@@ -0,0 +1,96 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+
+namespace ARMeilleure.Translation.Cache
+{
+    class CacheMemoryAllocator
+    {
+        private struct MemoryBlock : IComparable<MemoryBlock>
+        {
+            public int Offset { get; }
+            public int Size { get; }
+
+            public MemoryBlock(int offset, int size)
+            {
+                Offset = offset;
+                Size = size;
+            }
+
+            public int CompareTo([AllowNull] MemoryBlock other)
+            {
+                return Offset.CompareTo(other.Offset);
+            }
+        }
+
+        private readonly List<MemoryBlock> _blocks = new List<MemoryBlock>();
+
+        public CacheMemoryAllocator(int capacity)
+        {
+            _blocks.Add(new MemoryBlock(0, capacity));
+        }
+
+        public int Allocate(int size)
+        {
+            for (int i = 0; i < _blocks.Count; i++)
+            {
+                MemoryBlock block = _blocks[i];
+
+                if (block.Size > size)
+                {
+                    _blocks[i] = new MemoryBlock(block.Offset + size, block.Size - size);
+                    return block.Offset;
+                }
+                else if (block.Size == size)
+                {
+                    _blocks.RemoveAt(i);
+                    return block.Offset;
+                }
+            }
+
+            // We don't have enough free memory to perform the allocation.
+            return -1;
+        }
+
+        public void Free(int offset, int size)
+        {
+            Insert(new MemoryBlock(offset, size));
+        }
+
+        private void Insert(MemoryBlock block)
+        {
+            int index = _blocks.BinarySearch(block);
+
+            if (index < 0)
+            {
+                index = ~index;
+            }
+
+            if (index < _blocks.Count)
+            {
+                MemoryBlock next = _blocks[index];
+
+                int endOffs = block.Offset + block.Size;
+
+                if (next.Offset == endOffs)
+                {
+                    block = new MemoryBlock(block.Offset, block.Size + next.Size);
+                    _blocks.RemoveAt(index);
+                }
+            }
+
+            if (index > 0)
+            {
+                MemoryBlock prev = _blocks[index - 1];
+
+                if (prev.Offset + prev.Size == block.Offset)
+                {
+                    block = new MemoryBlock(block.Offset - prev.Size, block.Size + prev.Size);
+                    _blocks.RemoveAt(--index);
+                }
+            }
+
+            _blocks.Insert(index, block);
+        }
+    }
+}
-- 
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