[CPU] Preserve blocked leaf import waiters (#350)

src/SharpEmu.Core/Cpu/Native/DirectExecutionBackend.Imports.cs

@@ -1345,8 +1345,7 @@ public sealed partial class DirectExecutionBackend
 				out var blockContinuation,
 				out var hasBlockContinuation,
 				out var blockWakeKey,
-				out var blockResumeHandler,
+				out var blockWaiter,
-				out var blockWakeHandler,
 				out var blockDeadlineTimestamp);
 		if (consumedThreadBlock &&
 			TryYieldGuestThreadToHostStub(argPackPtr, dispatchIndex, returnRip, importStubEntry.Nid, blockReason))
@@ -1357,8 +1356,7 @@ public sealed partial class DirectExecutionBackend
 					GuestThreadExecution.CurrentGuestThreadHandle,
 					blockContinuation,
 					blockWakeKey,
-					blockResumeHandler,
+					blockWaiter,
-					blockWakeHandler,
 					blockDeadlineTimestamp);
 			}
 

src/SharpEmu.Core/Cpu/Native/DirectExecutionBackend.cs

@@ -443,10 +443,6 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 		// Stays set through the wake transition; Resume() consumes it when the thread pumps.
 		public IGuestThreadBlockWaiter? BlockWaiter { get; set; }
 
-		public Func<int>? BlockResumeHandler { get; set; }
-
-		public Func<bool>? BlockWakeHandler { get; set; }
-
 		public long BlockDeadlineTimestamp { get; set; }
 
 		public long ImportCount;
@@ -3215,43 +3211,6 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 			thread.HasBlockedContinuation = true;
 			thread.BlockWakeKey = wakeKey;
 			thread.BlockWaiter = waiter;
-			thread.BlockResumeHandler = null;
-			thread.BlockWakeHandler = null;
-			thread.BlockDeadlineTimestamp = blockDeadlineTimestamp;
-			TraceFocusedContinuation(
-				"register",
-				guestThreadHandle,
-				continuation,
-				wakeKey);
-		}
-	}
-
-	private void RegisterBlockedGuestThreadContinuation(
-		ulong guestThreadHandle,
-		GuestCpuContinuation continuation,
-		string wakeKey,
-		Func<int>? resumeHandler,
-		Func<bool>? wakeHandler,
-		long blockDeadlineTimestamp)
-	{
-		if (guestThreadHandle == 0 || continuation.Rip < 65536 || continuation.Rsp == 0)
-		{
-			return;
-		}
-
-		using (LockGate("RegisterBlockedContinuation"))
-		{
-			if (!_guestThreads.TryGetValue(guestThreadHandle, out var thread))
-			{
-				return;
-			}
-
-			thread.BlockedContinuation = continuation;
-			thread.HasBlockedContinuation = true;
-			thread.BlockWakeKey = wakeKey;
-			thread.BlockWaiter = null;
-			thread.BlockResumeHandler = resumeHandler;
-			thread.BlockWakeHandler = wakeHandler;
 			thread.BlockDeadlineTimestamp = blockDeadlineTimestamp;
 			TraceFocusedContinuation(
 				"register",
@@ -3567,11 +3526,10 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 
 				owner.State = GuestThreadRunState.Blocked;
 				owner.BlockReason = callbackReason ?? reason;
-				if (owner.BlockWakeHandler is not null && owner.BlockWakeHandler())
+				if (owner.BlockWaiter is not null && owner.BlockWaiter.TryWake())
 				{
 					owner.State = GuestThreadRunState.Ready;
 					owner.BlockReason = null;
-					owner.BlockWakeHandler = null;
 					owner.BlockDeadlineTimestamp = 0;
 				}
 			}
@@ -3583,7 +3541,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 			}
 
 			GuestCpuContinuation continuation = default;
-			Func<int>? resumeHandler = null;
+			IGuestThreadBlockWaiter? blockWaiter = null;
 			while (!ActiveForcedGuestExit)
 			{
 				WakeExpiredBlockedGuestThreads();
@@ -3604,9 +3562,8 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 						owner.BlockedContinuation = default;
 						owner.HasBlockedContinuation = false;
 						owner.BlockWakeKey = null;
-						resumeHandler = owner.BlockResumeHandler;
+						blockWaiter = owner.BlockWaiter;
-						owner.BlockResumeHandler = null;
+						owner.BlockWaiter = null;
-						owner.BlockWakeHandler = null;
 						owner.BlockDeadlineTimestamp = 0;
 						owner.BlockReason = null;
 						owner.State = GuestThreadRunState.Running;
@@ -3629,9 +3586,9 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 				return false;
 			}
 
-			if (resumeHandler is not null)
+			if (blockWaiter is not null)
 			{
-				continuation = continuation with { Rax = unchecked((ulong)(long)resumeHandler()) };
+				continuation = continuation with { Rax = unchecked((ulong)(long)blockWaiter.Resume()) };
 			}
 			if (_logGuestThreads)
 			{
@@ -3844,8 +3801,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 		bool savedHasBlockedContinuation;
 		GuestCpuContinuation savedBlockedContinuation;
 		string? savedBlockWakeKey;
-		Func<int>? savedBlockResumeHandler;
+		IGuestThreadBlockWaiter? savedBlockWaiter;
-		Func<bool>? savedBlockWakeHandler;
 		long savedBlockDeadlineTimestamp;
 		ulong exceptionStackBase;
 		lock (_guestThreadGate)
@@ -3981,8 +3937,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 			savedHasBlockedContinuation = target.HasBlockedContinuation;
 			savedBlockedContinuation = target.BlockedContinuation;
 			savedBlockWakeKey = target.BlockWakeKey;
-			savedBlockResumeHandler = target.BlockResumeHandler;
+			savedBlockWaiter = target.BlockWaiter;
-			savedBlockWakeHandler = target.BlockWakeHandler;
 			savedBlockDeadlineTimestamp = target.BlockDeadlineTimestamp;
 
 			target.State = GuestThreadRunState.Running;
@@ -3992,8 +3947,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 			target.HasBlockedContinuation = false;
 			target.BlockedContinuation = default;
 			target.BlockWakeKey = null;
-			target.BlockResumeHandler = null;
+			target.BlockWaiter = null;
-			target.BlockWakeHandler = null;
 			target.BlockDeadlineTimestamp = 0;
 		}
 
@@ -4041,8 +3995,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 			target.HasBlockedContinuation = savedHasBlockedContinuation;
 			target.BlockedContinuation = savedBlockedContinuation;
 			target.BlockWakeKey = savedBlockWakeKey;
-			target.BlockResumeHandler = savedBlockResumeHandler;
+			target.BlockWaiter = savedBlockWaiter;
-			target.BlockWakeHandler = savedBlockWakeHandler;
 			target.BlockDeadlineTimestamp = savedBlockDeadlineTimestamp;
 
 			// A condition/event wake can arrive while the parked thread is
@@ -4052,12 +4005,11 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 			// pthread wait remains parked forever after a GC suspension races it.
 			if (target.State == GuestThreadRunState.Blocked &&
 				target.HasBlockedContinuation &&
-				target.BlockWakeHandler is not null &&
+				target.BlockWaiter is not null &&
-				target.BlockWakeHandler())
+				target.BlockWaiter.TryWake())
 			{
 				target.State = GuestThreadRunState.Ready;
 				target.BlockReason = null;
-				target.BlockWakeHandler = null;
 				target.BlockDeadlineTimestamp = 0;
 				_readyGuestThreads.Enqueue(target);
 				Interlocked.Increment(ref _readyGuestThreadCount);

src/SharpEmu.HLE/GuestThreadExecution.cs

@@ -398,27 +398,6 @@ public static class GuestThreadExecution
         return true;
     }
 
-    public static bool TryConsumeCurrentThreadBlock(
-        out string reason,
-        out GuestCpuContinuation continuation,
-        out bool hasContinuation,
-        out string wakeKey,
-        out Func<int>? resumeHandler,
-        out Func<bool>? wakeHandler,
-        out long blockDeadlineTimestamp)
-    {
-        var consumed = TryConsumeCurrentThreadBlock(
-            out reason,
-            out continuation,
-            out hasContinuation,
-            out wakeKey,
-            out var waiter,
-            out blockDeadlineTimestamp);
-        resumeHandler = waiter is null ? null : waiter.Resume;
-        wakeHandler = waiter is null ? null : waiter.TryWake;
-        return consumed;
-    }
-
     public static long ComputeDeadlineTimestamp(TimeSpan timeout)
     {
         if (timeout <= TimeSpan.Zero)

tests/SharpEmu.Libs.Tests/Cpu/GuestThreadBlockWaiterRepresentationTests.cs

@@ -0,0 +1,112 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Reflection;
+using SharpEmu.Core.Cpu.Native;
+using SharpEmu.HLE;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Cpu;
+
+public sealed class GuestThreadBlockWaiterRepresentationTests
+{
+    [Fact]
+    public void SchedulerStoresOnlyTheWaiterObjectRepresentation()
+    {
+        var stateType = typeof(DirectExecutionBackend).GetNestedType(
+            "GuestThreadState",
+            BindingFlags.NonPublic);
+        Assert.NotNull(stateType);
+
+        var waiterProperty = stateType.GetProperty(
+            "BlockWaiter",
+            BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
+        Assert.NotNull(waiterProperty);
+        Assert.Equal(typeof(IGuestThreadBlockWaiter), waiterProperty.PropertyType);
+        Assert.Null(stateType.GetProperty(
+            "BlockResumeHandler",
+            BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic));
+        Assert.Null(stateType.GetProperty(
+            "BlockWakeHandler",
+            BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic));
+
+        var registerMethods = typeof(DirectExecutionBackend)
+            .GetMethods(BindingFlags.Instance | BindingFlags.NonPublic)
+            .Where(method => method.Name == "RegisterBlockedGuestThreadContinuation")
+            .ToArray();
+        var registerMethod = Assert.Single(registerMethods);
+        Assert.Contains(
+            registerMethod.GetParameters(),
+            parameter => parameter.ParameterType == typeof(IGuestThreadBlockWaiter));
+        Assert.DoesNotContain(
+            registerMethod.GetParameters(),
+            parameter => IsFuncParameter(parameter.ParameterType));
+
+        var consumeMethods = typeof(GuestThreadExecution)
+            .GetMethods(BindingFlags.Static | BindingFlags.Public)
+            .Where(method => method.Name == nameof(GuestThreadExecution.TryConsumeCurrentThreadBlock));
+        Assert.DoesNotContain(
+            consumeMethods.SelectMany(method => method.GetParameters()),
+            parameter => IsFuncParameter(parameter.ParameterType));
+    }
+
+    [Fact]
+    public void DelegateCompatibilityBridgeIsConsumedAsOneWaiterObject()
+    {
+        var previousThread = GuestThreadExecution.EnterGuestThread(0x1234);
+        try
+        {
+            var canWake = false;
+            var wakeCalls = 0;
+            var resumeCalls = 0;
+            Assert.True(GuestThreadExecution.RequestCurrentThreadBlock(
+                context: null,
+                reason: "test_wait",
+                wakeKey: "test_waiter:1",
+                resumeHandler: () =>
+                {
+                    resumeCalls++;
+                    return 42;
+                },
+                wakeHandler: () =>
+                {
+                    wakeCalls++;
+                    return canWake;
+                }));
+
+            Assert.True(GuestThreadExecution.TryConsumeCurrentThreadBlock(
+                out var reason,
+                out _,
+                out var hasContinuation,
+                out var wakeKey,
+                out IGuestThreadBlockWaiter? waiter,
+                out var deadline));
+            Assert.Equal("test_wait", reason);
+            Assert.Equal("test_waiter:1", wakeKey);
+            Assert.False(hasContinuation);
+            Assert.Equal(0, deadline);
+            Assert.NotNull(waiter);
+
+            Assert.False(waiter.TryWake());
+            canWake = true;
+            Assert.True(waiter.TryWake());
+            Assert.Equal(42, waiter.Resume());
+            Assert.Equal(2, wakeCalls);
+            Assert.Equal(1, resumeCalls);
+        }
+        finally
+        {
+            GuestThreadExecution.RestoreGuestThread(previousThread);
+        }
+    }
+
+    private static bool IsFuncParameter(Type parameterType)
+    {
+        var type = parameterType.IsByRef
+            ? parameterType.GetElementType()
+            : parameterType;
+        return type is not null &&
+            type.IsGenericType &&
+            type.GetGenericTypeDefinition() == typeof(Func<>);
+    }
+}