Fix and enable windows+arm disassembly (#3262)

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: timcassell

src/BenchmarkDotNet/BenchmarkDotNet.targets

@@ -25,6 +25,16 @@
                                     Condition="'%(RuntimeTargetsCopyLocalItems.NuGetPackageId)' == 'Gee.External.Capstone' AND '%(RuntimeTargetsCopyLocalItems.RuntimeIdentifier)' != '$(BenchmarkDotNetTargetPlatform)'" />
     </ItemGroup>
 
+    <!--
+      The SDK copies `runtimes/{RuntimeIdentifier}` assets only for .NETCoreApp.
+      Copy the native capstone for .NET Framework too, where the Arm64 disassembler loads it from that folder itself.
+    -->
+    <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
+      <RuntimeTargetsCopyLocalItems Condition="'%(RuntimeTargetsCopyLocalItems.NuGetPackageId)' == 'Gee.External.Capstone'">
+        <CopyLocal>true</CopyLocal>
+      </RuntimeTargetsCopyLocalItems>
+    </ItemGroup>
+
     <!-- Remove unnecessary satellite assemblies. -->
     <ItemGroup>
       <ResourceCopyLocalItems

src/BenchmarkDotNet/Disassemblers/Arm64Disassembler.cs

@@ -11,7 +11,7 @@ internal class Arm64Disassembler : ClrMdDisassembler
         protected override IEnumerable<Asm> Decode(byte[] code, ulong startAddress, State state, int depth, IClrMethod currentMethod, DisassemblySyntax syntax)
         {
             const Arm64DisassembleMode disassembleMode = Arm64DisassembleMode.Arm;
-            using (CapstoneArm64Disassembler disassembler = CapstoneDisassembler.CreateArm64Disassembler(disassembleMode))
+            using (CapstoneArm64Disassembler disassembler = CapstoneFactory.CreateArm64Disassembler(disassembleMode))
             {
                 // Enables disassemble details, which are disabled by default, to provide more detailed information on
                 // disassembled binary code.

src/BenchmarkDotNet/Disassemblers/CapstoneFactory.cs

@@ -0,0 +1,58 @@
+using Gee.External.Capstone;
+using Gee.External.Capstone.Arm64;
+#if !NET
+using BenchmarkDotNet.Environments;
+using BenchmarkDotNet.Extensions;
+using BenchmarkDotNet.Helpers;
+using System.Runtime.InteropServices;
+using RuntimeInformation = BenchmarkDotNet.Portability.RuntimeInformation;
+#endif
+
+namespace BenchmarkDotNet.Disassemblers;
+
+internal static class CapstoneFactory
+{
+    internal static CapstoneArm64Disassembler CreateArm64Disassembler(Arm64DisassembleMode disassembleMode)
+    {
+#if !NET
+        _ = FrameworkNativeLibrary.Handle.Value;
+#endif
+        return CapstoneDisassembler.CreateArm64Disassembler(disassembleMode);
+    }
+
+#if !NET
+    /// <summary>
+    /// .NET Framework does not probe <c>runtimes/{rid}/native</c>, where BenchmarkDotNet.targets copies the native capstone.
+    /// Once it is loaded by its full path, the P/Invokes that name the module bind to the loaded library.
+    /// When the file is not there, the default search applies - a build for a specific RuntimeIdentifier puts it next to the application.
+    /// </summary>
+    private static class FrameworkNativeLibrary
+    {
+        internal static readonly Lazy<IntPtr> Handle = new(Load);
+
+        private static IntPtr Load()
+        {
+            if (!RuntimeInformation.IsFullFramework)
+                return IntPtr.Zero;
+
+            string? rid = RuntimeInformation.GetCurrentPlatform() switch
+            {
+                Platform.X86 => "win-x86",
+                Platform.X64 => "win-x64",
+                Platform.Arm64 => "win-arm64",
+                _ => null
+            };
+            var assembly = typeof(CapstoneDisassembler).Assembly;
+            string location = ShadowCopyHelper.TryGetOriginalLocation(assembly, out var originalLocation) ? originalLocation : assembly.Location;
+            if (rid is null || location.IsBlank())
+                return IntPtr.Zero;
+
+            string path = Path.Combine(Path.GetDirectoryName(location)!, "runtimes", rid, "native", "capstone.dll");
+            return File.Exists(path) ? LoadLibraryW(path) : IntPtr.Zero;
+        }
+
+        [DllImport("kernel32", ExactSpelling = true, CharSet = CharSet.Unicode)]
+        private static extern IntPtr LoadLibraryW(string lpLibFileName);
+    }
+#endif
+}

src/BenchmarkDotNet/Disassemblers/DataContracts.cs

@@ -142,7 +142,7 @@ public override Arm64AsmData Read(ref Utf8JsonReader reader, Type typeToConvert,
             if (reader.TokenType != JsonTokenType.EndObject)
                 throw new JsonException("Invalid JSON");
 
-            using var disassembler = CapstoneDisassembler.CreateArm64Disassembler(Arm64DisassembleMode.Arm);
+            using var disassembler = CapstoneFactory.CreateArm64Disassembler(Arm64DisassembleMode.Arm);
             disassembler.EnableInstructionDetails = true;
             disassembler.DisassembleSyntax = syntax;
             var instruction = disassembler.Disassemble(instructionBytes, instructionAddress).SingleOrDefault();

src/BenchmarkDotNet/Disassemblers/DisassemblyDiagnoser.cs

@@ -121,12 +121,6 @@ public async IAsyncEnumerable<ValidationError> ValidateAsync(ValidationParameter
                 yield break;
             }
 
-            if (currentPlatform == Platform.Arm64 && OsDetector.IsWindows())
-            {
-                yield return new ValidationError(true, $"{nameof(DisassemblyDiagnoser)} does not support Arm on Windows");
-                yield break;
-            }
-
             if (Config.RunInHost && OsDetector.IsMacOS())
             {
                 yield return new ValidationError(true, "Disassembling in the host process is not supported on MacOS");

tests/BenchmarkDotNet.IntegrationTests/DisassemblyDiagnoserTests.cs

@@ -1,4 +1,4 @@
-using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Attributes;
 using BenchmarkDotNet.Columns;
 using BenchmarkDotNet.Configs;
 using BenchmarkDotNet.Detectors;
@@ -10,7 +10,6 @@
 using BenchmarkDotNet.Jobs;
 using BenchmarkDotNet.Portability;
 using BenchmarkDotNet.Tests.Loggers;
-using BenchmarkDotNet.Tests.XUnit;
 using BenchmarkDotNet.Toolchains;
 using BenchmarkDotNet.Toolchains.Framework;
 using BenchmarkDotNet.Toolchains.InProcess.Emit;
@@ -32,6 +31,12 @@ public static IEnumerable<object[]> GetAllJits()
 
             if (RuntimeInformation.IsFullFramework)
             {
+                if (RuntimeInformation.GetCurrentPlatform() is Platform.Arm64)
+                {
+                    // RyuJit for desktop .NET arm64. Supported only on net481, but we have to match the tfm in our test project.
+                    yield return [Jit.RyuJit, Platform.Arm64, CsProjFrameworkToolchain.Net472];
+                }
+                // Framework on arm emulates x86, so these platform targets should work on both.
                 yield return [Jit.LegacyJit, Platform.X86, CsProjFrameworkToolchain.Net472]; // 32bit LegacyJit for desktop .NET
                 yield return [Jit.LegacyJit, Platform.X64, CsProjFrameworkToolchain.Net472]; // 64bit LegacyJit for desktop .NET
                 yield return [Jit.RyuJit, Platform.X64, CsProjFrameworkToolchain.Net472]; // RyuJit for desktop .NET
@@ -87,7 +92,7 @@ public void Recursive()
             [MethodImpl(MethodImplOptions.NoInlining)] public void Benchmark(bool justAnOverload) { } // we need to test overloads (#562)
         }
 
-        [TheoryEnvSpecific("Not supported on Windows+Arm", EnvRequirement.NonWindowsArm)]
+        [Theory]
         [MemberData(nameof(GetAllJits), DisableDiscoveryEnumeration = true)]
         [Trait(Constants.Category, Constants.BackwardCompatibilityCategory)]
         public void CanDisassembleAllMethodCalls(Jit jit, Platform platform, IToolchain toolchain)
@@ -107,7 +112,7 @@ public void CanDisassembleAllMethodCalls(Jit jit, Platform platform, IToolchain
             AssertDisassemblyResult(result, $"{nameof(WithCalls.Recursive)}()");
         }
 
-        [TheoryEnvSpecific("Not supported on Windows+Arm", EnvRequirement.NonWindowsArm)]
+        [Theory]
         [MemberData(nameof(GetAllJits), DisableDiscoveryEnumeration = true)]
         [Trait(Constants.Category, Constants.BackwardCompatibilityCategory)]
         public void CanDisassembleAllMethodCallsUsingFilters(Jit jit, Platform platform, IToolchain toolchain)
@@ -133,7 +138,7 @@ public void CanDisassembleAllMethodCallsUsingFilters(Jit jit, Platform platform,
             public T Create() => new T();
         }
 
-        [TheoryEnvSpecific("Not supported on Windows+Arm", EnvRequirement.NonWindowsArm)]
+        [Theory]
         [MemberData(nameof(GetAllJits), DisableDiscoveryEnumeration = true)]
         [Trait(Constants.Category, Constants.BackwardCompatibilityCategory)]
         public void CanDisassembleGenericTypes(Jit jit, Platform platform, IToolchain toolchain)
@@ -154,7 +159,7 @@ public class WithInlineable
             [Benchmark] public void JustReturn() { }
         }
 
-        [TheoryEnvSpecific("Not supported on Windows+Arm", EnvRequirement.NonWindowsArm)]
+        [Theory]
         [MemberData(nameof(GetAllJits), DisableDiscoveryEnumeration = true)]
         [Trait(Constants.Category, Constants.BackwardCompatibilityCategory)]
         public void CanDisassembleInlinableBenchmarks(Jit jit, Platform platform, IToolchain toolchain)
@@ -188,7 +193,7 @@ public class WithGeneratedMemberNames
             [MethodImpl(MethodImplOptions.NoInlining)] public virtual void ForDisassemblyDiagnoser() { }
         }
 
-        [TheoryEnvSpecific("Not supported on Windows+Arm", EnvRequirement.NonWindowsArm)]
+        [Theory]
         [MemberData(nameof(GetAllJits), DisableDiscoveryEnumeration = true)]
         [Trait(Constants.Category, Constants.BackwardCompatibilityCategory)]
         public void CanDisassembleWhenBenchmarkDeclaresGeneratedMemberNames(Jit jit, Platform platform, IToolchain toolchain)

tests/BenchmarkDotNet.Tests/Serialization/DisassemblerModelSerializationTests.cs

@@ -1,7 +1,6 @@
 using AwesomeAssertions;
 using BenchmarkDotNet.Disassemblers;
 using BenchmarkDotNet.Serialization;
-using BenchmarkDotNet.Tests.XUnit;
 using Gee.External.Capstone;
 using Gee.External.Capstone.Arm64;
 using Iced.Intel;
@@ -105,15 +104,15 @@ public void IntelAsmSerializationTest()
         Assert.Equivalent(model, result, strict: true);
     }
 
-    [FactEnvSpecific("ARM64 disassembler is not supported on .NET Framework or Windows+Arm environment", EnvRequirement.NonFullFramework, EnvRequirement.NonWindowsArm)]
+    [Fact]
     public void Arm64AsmSerializationTest()
     {
         // Arrange
         byte[] instructionBytes = [0xE1, 0x0B, 0x40, 0xB9]; // ldr w1, [sp, #8]
         var disassembleSyntax = DisassembleSyntax.Intel;
 
         // Create instruction instance by using disassembler.
-        using var disassembler = CapstoneDisassembler.CreateArm64Disassembler(Arm64DisassembleMode.Arm);
+        using var disassembler = CapstoneFactory.CreateArm64Disassembler(Arm64DisassembleMode.Arm);
         disassembler.EnableInstructionDetails = true;
         disassembler.DisassembleSyntax = disassembleSyntax;