Fixed critical issue in CPUAccelerator runtime related to Shared Memory allocations and Warp operations.

Src/ILGPU.Algorithms.Tests/WarpExtensionTests.Find.cs

@@ -0,0 +1,153 @@
+// ---------------------------------------------------------------------------------------
+//                                   ILGPU Algorithms
+//                           Copyright (c) 2022 ILGPU Project
+//                                    www.ilgpu.net
+//
+// File: WarpExtensionTests.Find.cs
+//
+// This file is part of ILGPU and is distributed under the University of Illinois Open
+// Source License. See LICENSE.txt for details.
+// ---------------------------------------------------------------------------------------
+
+using ILGPU.Algorithms.ScanReduceOperations;
+using ILGPU.AtomicOperations;
+using ILGPU.Runtime;
+using ILGPU.Tests;
+using ILGPU.Util;
+using System;
+using System.Runtime.CompilerServices;
+using Xunit;
+
+#pragma warning disable xUnit1026
+#pragma warning disable CA1815
+
+namespace ILGPU.Algorithms.Tests
+{
+    partial class WarpExtensionTests
+    {
+        internal readonly struct LaneEntry :
+            IScanReduceOperation<LaneEntry>,
+            IAtomicOperation<LaneEntry>,
+            ICompareExchangeOperation<LaneEntry>
+        {
+            public LaneEntry(int distance, int laneIndex)
+            {
+                Distance = distance;
+                LaneIndex = laneIndex;
+            }
+
+            public string CLCommand => string.Empty;
+            public LaneEntry Identity => new LaneEntry(int.MaxValue, int.MaxValue);
+
+            public int Distance { get; }
+            public int LaneIndex { get; }
+
+            public LaneEntry Apply(LaneEntry first, LaneEntry second) =>
+                Utilities.Select(first.Distance < second.Distance, first, second);
+
+            public LaneEntry Operation(LaneEntry current, LaneEntry value) =>
+                Apply(current, value);
+
+            public void AtomicApply(ref LaneEntry target, LaneEntry value) =>
+                Atomic.MakeAtomic(ref target, value, this, this);
+
+            public LaneEntry CompareExchange(
+                ref LaneEntry target,
+                LaneEntry compare,
+                LaneEntry value)
+            {
+                ref long targetL = ref Unsafe.As<LaneEntry, long>(ref target);
+                long compareL = Unsafe.As<LaneEntry, long>(ref compare);
+                long valueL = Unsafe.As<LaneEntry, long>(ref value);
+                long result = Atomic.CompareExchange(ref targetL, compareL, valueL);
+                return Unsafe.As<long, LaneEntry>(ref result);
+            }
+
+            public bool IsSame(LaneEntry left, LaneEntry right) =>
+                left.Distance == right.Distance & left.LaneIndex == right.LaneIndex;
+
+            public override string ToString() => $"{LaneIndex}: {Distance}d";
+        }
+
+        public static void FindKernel(
+            ArrayView<int> values,
+            ArrayView<int> origins,
+            ArrayView<int> results)
+        {
+            const int MaxGroupSize = 1024;
+
+            int localDistance = int.MaxValue;
+            ref var bestSharedDistance = ref SharedMemory.Allocate<int>();
+            var sharedDistanceValues = SharedMemory.Allocate<int>(MaxGroupSize);
+            for (int i = Group.IdxX; i < MaxGroupSize; i += Group.DimX)
+                sharedDistanceValues[Group.IdxX] = localDistance;
+            Group.Barrier();
+
+            int source = values[Grid.IdxX];
+            if (source < 0)
+                return;
+            for (int i = Group.IdxX; i < origins.IntLength; i += Group.DimX)
+            {
+                int origin = origins[i];
+                int result = Math.Abs(origin - source);
+
+                localDistance = Utilities.Select(
+                    result < localDistance,
+                    result,
+                    localDistance);
+            }
+
+            // Commit changes to shared memory
+            sharedDistanceValues[Group.IdxX] = localDistance;
+            Group.Barrier();
+
+            // Determine the best value in the first warp
+            if (Warp.WarpIdx == 0)
+            {
+                LaneEntry entry = default(LaneEntry).Identity;
+                for (int i = Warp.LaneIdx; i < Group.DimX; i += Warp.WarpSize)
+                {
+                    var bestFit = WarpExtensions.Reduce<LaneEntry, LaneEntry>(
+                        new(sharedDistanceValues[i], i));
+                    entry = entry.Apply(entry, bestFit);
+                }
+                Warp.Barrier();
+
+                // First lane contains the actual result
+                if (Warp.IsFirstLane)
+                    bestSharedDistance = sharedDistanceValues[entry.LaneIndex];
+            }
+            Group.Barrier();
+
+            // First thread should have all results
+            if (Group.IsFirstThread)
+                results[Grid.IdxX] = bestSharedDistance;
+        }
+
+        [Fact]
+        [KernelMethod(nameof(FindKernel))]
+        public void FindDistances()
+        {
+            var values = new int[] { 1, 2, 3 };
+            var origins = new int[] { 7, 5, 1, 4, 5, 1, 2, 4, 6, 7, 8 };
+            var results = new int[] { 0, 0, 1 };
+
+            using var valuesBuffer = Accelerator.Allocate1D<int>(values);
+            using var originsBuffer = Accelerator.Allocate1D<int>(origins);
+            using var resultsBuffer = Accelerator.Allocate1D<int>(values.Length);
+
+            Execute(
+                new KernelConfig(
+                    values.Length,
+                    Accelerator.MaxNumThreadsPerGroup),
+                valuesBuffer.View.AsContiguous(),
+                originsBuffer.View.AsContiguous(),
+                resultsBuffer.View.AsContiguous());
+
+            Verify(resultsBuffer.View, results);
+        }
+    }
+}
+
+#pragma warning restore xUnit1026
+#pragma warning restore CA1815

Src/ILGPU.Algorithms.Tests/WarpExtensionTests.tt

@@ -1,6 +1,6 @@
 // ---------------------------------------------------------------------------------------
 //                                   ILGPU Algorithms
-//                           Copyright (c) 2021 ILGPU Project
+//                        Copyright (c) 2021-2022 ILGPU Project
 //                                    www.ilgpu.net
 //
 // File: WarpExtensionTests.tt/WarpExtensionTests.cs
@@ -22,7 +22,7 @@ using System.Linq;
 using Xunit;
 using Xunit.Abstractions;
 
-#pragma warning disable xUnit1026 
+#pragma warning disable xUnit1026
 
 namespace ILGPU.Algorithms.Tests
 {
@@ -120,7 +120,7 @@ namespace ILGPU.Algorithms.Tests
 
             var sequence = sequencer.ComputeSequence(start, stepSize, size);
             input.CopyFromCPU(stream, sequence);
-            
+
             Execute<KernelConfig, T, TFunction>((1, size), input.View, output.View);
 
             T expected = CalcValue(sequence, func);
@@ -151,9 +151,9 @@ namespace ILGPU.Algorithms.Tests
 
             var sequence = sequencer.ComputeSequence(start, stepSize, size);
             input.CopyFromCPU(stream, sequence);
-            
+
             Execute<KernelConfig, T, TFunction>((1, size), input.View, output.View);
-            
+
             var expected = Enumerable.Repeat(CalcValue(sequence, func), size).ToArray();
             Verify(output.View, expected);
         }
@@ -179,7 +179,7 @@ namespace ILGPU.Algorithms.Tests
 
             var sequence = sequencer.ComputeSequence(start, stepSize, size);
             input.CopyFromCPU(stream, sequence);
-            
+
             Execute<KernelConfig, T, TFunction>((1, size), input.View, output.View);
 
             T[] expected = CalcValues(sequence, func, ScanKind.Exclusive);
@@ -208,7 +208,7 @@ namespace ILGPU.Algorithms.Tests
 
             var sequence = sequencer.ComputeSequence(start, stepSize, size);
             input.CopyFromCPU(stream, sequence);
-            
+
             Execute<KernelConfig, T, TFunction>((1, size), input.View, output.View);
 
             T[] expected = CalcValues(sequence, func, ScanKind.Exclusive);
@@ -238,13 +238,13 @@ namespace ILGPU.Algorithms.Tests
 
             var sequence = sequencer.ComputeSequence(start, stepSize, size);
             input.CopyFromCPU(stream, sequence);
-            
+
             Execute<KernelConfig, T, TFunction>((1, size), input.View, output.View);
-            
+
             T[] expected = CalcValues(sequence, func, ScanKind.Inclusive);
             Verify(output.View, expected);
         }
-        
+
         #region Helper Methods
 
         private static T CalcValue<T, TFunction>(T[] values, TFunction func)
@@ -272,7 +272,7 @@ namespace ILGPU.Algorithms.Tests
 
             if (kind == ScanKind.Exclusive)
             {
-                T[] zero = { default }; 
+                T[] zero = { default };
                 result = zero.Concat(result.Take(result.Length - 1)).ToArray();
             }
             return result;

Src/ILGPU/Backends/IL/ILBackend.cs

@@ -193,7 +193,10 @@ protected sealed override CompiledKernel Compile(
                 kernelMethod,
                 taskType,
                 taskConstructor,
-                taskArgumentMapping);
+                taskArgumentMapping,
+                backendContext.SharedAllocations.Length +
+                    backendContext.DynamicSharedAllocations.Length,
+                backendContext.SharedMemorySpecification.StaticSize);
         }
 
         /// <summary>

Src/ILGPU/Backends/IL/ILCompiledKernel.cs

@@ -1,6 +1,6 @@
 // ---------------------------------------------------------------------------------------
 //                                        ILGPU
-//                        Copyright (c) 2018-2021 ILGPU Project
+//                        Copyright (c) 2018-2022 ILGPU Project
 //                                    www.ilgpu.net
 //
 // File: ILCompiledKernel.cs
@@ -35,13 +35,21 @@ public sealed class ILCompiledKernel : CompiledKernel
         /// <param name="taskArgumentMapping">
         /// Mapping of argument indices to fields.
         /// </param>
+        /// <param name="numSharedMemoryAllocations">
+        /// The number of shared-memory allocations.
+        /// </param>
+        /// <param name="allocatedSharedMemorySize">
+        /// The amount of statically allocated bytes of shared memory.
+        /// </param>
         internal ILCompiledKernel(
             Context context,
             EntryPoint entryPoint,
             MethodInfo kernelMethod,
             Type taskType,
             ConstructorInfo taskConstructor,
-            ImmutableArray<FieldInfo> taskArgumentMapping)
+            ImmutableArray<FieldInfo> taskArgumentMapping,
+            int numSharedMemoryAllocations,
+            int allocatedSharedMemorySize)
             : base(context, entryPoint, null)
         {
             KernelMethod = kernelMethod;
@@ -50,6 +58,8 @@ internal ILCompiledKernel(
             TaskType = taskType;
             TaskConstructor = taskConstructor;
             TaskArgumentMapping = taskArgumentMapping;
+            NumSharedMemoryAllocations = numSharedMemoryAllocations;
+            AllocatedSharedMemorySize = allocatedSharedMemorySize;
         }
 
         #endregion
@@ -81,6 +91,16 @@ internal ILCompiledKernel(
         /// </summary>
         internal ImmutableArray<FieldInfo> TaskArgumentMapping { get; }
 
+        /// <summary>
+        /// Returns the number of shared-memory allocations.
+        /// </summary>
+        public int NumSharedMemoryAllocations { get; }
+
+        /// <summary>
+        /// Returns the size of statically allocated shared memory in bytes.
+        /// </summary>
+        public int AllocatedSharedMemorySize { get; }
+
         #endregion
     }
 }

Src/ILGPU/Runtime/CPU/CPURuntimeContext.cs

@@ -1,6 +1,6 @@
 // ---------------------------------------------------------------------------------------
 //                                        ILGPU
-//                           Copyright (c) 2021 ILGPU Project
+//                        Copyright (c) 2021-2022 ILGPU Project
 //                                    www.ilgpu.net
 //
 // File: CPURuntimeContext.cs
@@ -171,19 +171,19 @@ protected CPURuntimeContext(CPUMultiprocessor multiprocessor)
         /// <param name="operation">The operation to perform.</param>
         /// <returns>The determined result value for all threads.</returns>
         /// <remarks>
-        /// It internally acquires a lock using <see cref="AquireLock"/> and determines
+        /// It internally acquires a lock using <see cref="AcquireLock"/> and determines
         /// a "main thread" that can execute the given operation in sync with all
         /// other threads. Afterwards, all threads continue and query the result of
         /// the synchronized operation and the main thread releases its lock.
         /// </remarks>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        protected T PerformLocked<TParent, TOperation, T>(
+        protected T PerformLockStep<TParent, TOperation, T>(
             TParent parent,
             TOperation operation)
             where TParent : IParent
             where TOperation : ILockedOperation<T>
         {
-            bool isMainThread = AquireLock();
+            bool isMainThread = AcquireLock();
             if (isMainThread)
                 operation.ApplySyncInMainThread();
             parent.Barrier();
@@ -198,7 +198,7 @@ protected T PerformLocked<TParent, TOperation, T>(
         /// </summary>
         /// <returns>True, if the current thread is the main thread.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        protected bool AquireLock() =>
+        protected bool AcquireLock() =>
             Interlocked.CompareExchange(ref memoryLock, 1, 0) == 0;
 
         /// <summary>
@@ -240,7 +240,7 @@ protected T Broadcast<TParent, T>(
             where T : unmanaged
         {
             // Allocate a compatible view to perform the actual broadcast operation
-            var view = PerformLocked<
+            var view = PerformLockStep<
                 TParent,
                 GetBroadcastMemory<T>,
                 ArrayView<T>>(