Only need single stack for stacks (#7375)

NethermindEth · Sep 2, 2024 · 76d5fd6 · 76d5fd6
1 parent 29f2a20
commit 76d5fd6
Showing 1 changed file with 18 additions and 33 deletions.
diff --git a/src/Nethermind/Nethermind.Evm/EvmState.cs b/src/Nethermind/Nethermind.Evm/EvmState.cs
@@ -23,18 +23,21 @@ public class EvmState : IDisposable // TODO: rename to CallState
         private class StackPool
         {
             private readonly int _maxCallStackDepth;
+            private readonly struct StackItem(byte[] dataStack, int[] returnStack)
+            {
+                public readonly byte[] DataStack = dataStack;
+                public readonly int[] ReturnStack = returnStack;
+            }
 
             // TODO: we have wrong call depth calculation somewhere
             public StackPool(int maxCallStackDepth = VirtualMachine.MaxCallDepth * 2)
             {
                 _maxCallStackDepth = maxCallStackDepth;
             }
 
-            private readonly Stack<byte[]> _dataStackPool = new(32);
-            private readonly Stack<int[]> _returnStackPool = new(32);
+            private readonly Stack<StackItem> _stackPool = new(32);
 
-            private int _dataStackPoolDepth;
-            private int _returnStackPoolDepth;
+            private int _stackPoolDepth;
 
             /// <summary>
             /// The word 'return' acts here once as a verb 'to return stack to the pool' and once as a part of the
@@ -44,45 +47,27 @@ public StackPool(int maxCallStackDepth = VirtualMachine.MaxCallDepth * 2)
             /// <param name="returnStack"></param>
             public void ReturnStacks(byte[] dataStack, int[] returnStack)
             {
-                _dataStackPool.Push(dataStack);
-                _returnStackPool.Push(returnStack);
+                _stackPool.Push(new(dataStack, returnStack));
             }
 
-            private byte[] RentDataStack()
-            {
-                if (_dataStackPool.TryPop(out byte[] result))
-                {
-                    return result;
-                }
-
-                _dataStackPoolDepth++;
-                if (_dataStackPoolDepth > _maxCallStackDepth)
-                {
-                    EvmStack.ThrowEvmStackOverflowException();
-                }
-
-                return new byte[(EvmStack.MaxStackSize + EvmStack.RegisterLength) * 32];
-            }
-
-            private int[] RentReturnStack()
+            public (byte[], int[]) RentStacks()
             {
-                if (_returnStackPool.TryPop(out int[] result))
+                if (_stackPool.TryPop(out StackItem result))
                 {
-                    return result;
+                    return (result.DataStack, result.ReturnStack);
                 }
 
-                _returnStackPoolDepth++;
-                if (_returnStackPoolDepth > _maxCallStackDepth)
+                _stackPoolDepth++;
+                if (_stackPoolDepth > _maxCallStackDepth)
                 {
                     EvmStack.ThrowEvmStackOverflowException();
                 }
 
-                return new int[EvmStack.ReturnStackSize];
-            }
-
-            public (byte[], int[]) RentStacks()
-            {
-                return (RentDataStack(), RentReturnStack());
+                return
+                (
+                    new byte[(EvmStack.MaxStackSize + EvmStack.RegisterLength) * 32],
+                    new int[EvmStack.ReturnStackSize]
+                );
             }
         }
         private static readonly ThreadLocal<StackPool> _stackPool = new(() => new StackPool());