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Replace IsWow64Process2 P/Invoke with managed RuntimeInformation APIs #15608

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Replace IsWow64Process2 P/Invoke with managed RuntimeInformation APIs #15608

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38c367e
Replace IsWow64Process2 P/Invoke with RuntimeInformation APIs
nohwnd Mar 27, 2026
b89776b
Update V2.CLI file count for RuntimeInformation DLL
nohwnd Mar 30, 2026
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2 changes: 1 addition & 1 deletion eng/verify-nupkgs.ps1
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ function Verify-Nuget-Packages {
"Microsoft.CodeCoverage" = 76
"Microsoft.NET.Test.Sdk" = 26
"Microsoft.TestPlatform" = 545
"Microsoft.VisualStudio.TestTools.TestPlatform.V2.CLI" = 388
"Microsoft.VisualStudio.TestTools.TestPlatform.V2.CLI" = 389
"Microsoft.TestPlatform.Build" = 21
"Microsoft.TestPlatform.CLI" = 483
"Microsoft.TestPlatform.Extensions.TrxLogger" = 35
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1 change: 1 addition & 0 deletions ...soft.TestPlatform.PlatformAbstractions/Microsoft.TestPlatform.PlatformAbstractions.csproj
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Expand Up @@ -13,6 +13,7 @@
<Reference Include="System.Configuration" />
<Reference Include="System" />
<Reference Include="Microsoft.CSharp" />
<PackageReference Include="System.Runtime.InteropServices.RuntimeInformation" Version="4.3.0" />
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@nohwnd nohwnd Apr 10, 2026

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Move to it's own item group.

</ItemGroup>

<ItemGroup>
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5 changes: 0 additions & 5 deletions src/Microsoft.TestPlatform.PlatformAbstractions/common/NativeMethods.cs
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Expand Up @@ -9,11 +9,6 @@ namespace Microsoft.VisualStudio.TestPlatform.PlatformAbstractions;
internal class NativeMethods
{
public const ushort IMAGE_FILE_MACHINE_ARM64 = 0xAA64;
public const ushort IMAGE_FILE_MACHINE_UNKNOWN = 0;

[DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool IsWow64Process2([In] IntPtr process, [Out] out ushort processMachine, [Out] out ushort nativeMachine);

// A pointer to a value that is set to TRUE if the process is running under WOW64.
// If the process is running under 32-bit Windows, the value is set to FALSE.
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40 changes: 8 additions & 32 deletions src/Microsoft.TestPlatform.PlatformAbstractions/net462/System/PlatformEnvironment.cs
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Expand Up @@ -4,8 +4,7 @@
#if NETFRAMEWORK || NETSTANDARD2_0

using System;
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.InteropServices;

using Microsoft.VisualStudio.TestPlatform.PlatformAbstractions.Interfaces;

Expand All @@ -21,38 +20,15 @@ public PlatformArchitecture Architecture
{
get
{
return _architecture ??= Environment.Is64BitOperatingSystem
? IsArm64()
? PlatformArchitecture.ARM64
: PlatformArchitecture.X64
: PlatformArchitecture.X86;
}
}

private static bool IsArm64()
{
try
{
var currentProcess = Process.GetCurrentProcess();
if (!NativeMethods.IsWow64Process2(currentProcess.Handle, out ushort _, out ushort nativeMachine))
return _architecture ??= RuntimeInformation.OSArchitecture switch
{
throw new Win32Exception();
}

// If nativeMachine is IMAGE_FILE_MACHINE_ARM64 it means that we're running on ARM64 architecture device.
return nativeMachine == NativeMethods.IMAGE_FILE_MACHINE_ARM64;
}
catch
{
// At the moment we cannot log messages inside the Microsoft.TestPlatform.PlatformAbstractions.
// We did an attempt in https://github.com/microsoft/vstest/pull/3422 - 17.2.0-preview-20220301-01 - but we reverted after
// because we broke a scenario where for .NET Framework application inside the test host
// we loaded runner version of Microsoft.TestPlatform.PlatformAbstractions but newer version Microsoft.TestPlatform.ObjectModel(the one close
// to the test container) and the old PlatformAbstractions doesn't contain the methods expected by the new ObjectModel throwing
// a MissedMethodException.
System.Runtime.InteropServices.Architecture.X86 => PlatformArchitecture.X86,
System.Runtime.InteropServices.Architecture.X64 => PlatformArchitecture.X64,
System.Runtime.InteropServices.Architecture.Arm => PlatformArchitecture.ARM,
System.Runtime.InteropServices.Architecture.Arm64 => PlatformArchitecture.ARM64,
_ => throw new NotSupportedException(),
};
}

return false;
}

/// <inheritdoc />
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102 changes: 31 additions & 71 deletions src/Microsoft.TestPlatform.PlatformAbstractions/net462/System/ProcessHelper.cs
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Expand Up @@ -2,21 +2,17 @@
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System;
using System.ComponentModel;
using System.Diagnostics;
using System.IO;
# if NETCOREAPP || NETSTANDARD2_0_OR_GREATER
using System.Runtime.InteropServices;
#endif

using Microsoft.VisualStudio.TestPlatform.PlatformAbstractions.Interfaces;

namespace Microsoft.VisualStudio.TestPlatform.PlatformAbstractions;

public partial class ProcessHelper : IProcessHelper
{
#if NETFRAMEWORK || NETSTANDARD2_0_OR_GREATER
private PlatformArchitecture? _currentProcessArchitecture;

/// <inheritdoc/>
public string GetCurrentProcessLocation()
=> Path.GetDirectoryName(GetCurrentProcessFileName());
Expand All @@ -30,22 +26,14 @@ public nint GetProcessHandle(int processId) =>
/// <inheritdoc/>
public PlatformArchitecture GetCurrentProcessArchitecture()
{
// If we already cached the current process architecture, no need to figure it out again.
if (_currentProcessArchitecture is not null)
{
return _currentProcessArchitecture.Value;
}

// When this is current process, we can just check if IntPointer size to get if we are 64-bit or 32-bit.
// When it is 32-bit we can just return, if it is 64-bit we need to clarify if x64 or arm64.
if (IntPtr.Size == 4)
return RuntimeInformation.ProcessArchitecture switch
{
_currentProcessArchitecture = PlatformArchitecture.X86;
return _currentProcessArchitecture.Value;
}

_currentProcessArchitecture ??= GetProcessArchitecture(_currentProcess.Id);
return _currentProcessArchitecture.Value;
Architecture.X86 => PlatformArchitecture.X86,
Architecture.X64 => PlatformArchitecture.X64,
Architecture.Arm => PlatformArchitecture.ARM,
Architecture.Arm64 => PlatformArchitecture.ARM64,
_ => throw new NotSupportedException(),
};
}
#endif

Expand All @@ -60,76 +48,48 @@ public PlatformArchitecture GetProcessArchitecture(int processId)
}
#endif

// If the current process is 64-bit, or this is any remote process, we need to query it via native api.
var process = processId == _currentProcess.Id ? _currentProcess : Process.GetProcessById(processId);
// For the current process, use RuntimeInformation directly.
if (processId == _currentProcess.Id)
{
return GetCurrentProcessArchitecture();
}

// For remote processes, we need Windows APIs.
var process = Process.GetProcessById(processId);
try
{
if (!NativeMethods.IsWow64Process2(process.Handle, out ushort processMachine, out ushort nativeMachine))
if (!Environment.Is64BitOperatingSystem)
{
throw new Win32Exception();
return PlatformArchitecture.X86;
}

if (processMachine != NativeMethods.IMAGE_FILE_MACHINE_UNKNOWN)
var isWow64Succeeded = NativeMethods.IsWow64Process(process.Handle, out var isWow64);
if (isWow64Succeeded && isWow64)
{
// The process is running using WOW64, which suggests it is 32-bit (or any of the other machines, that we cannot
// handle, so we just assume x86).
// The process is running using WOW64, which means it is 32-bit.
return PlatformArchitecture.X86;
}

// If processMachine is IMAGE_FILE_MACHINE_UNKNOWN mean that we're not running using WOW64 emulation.
// If nativeMachine is IMAGE_FILE_MACHINE_ARM64 mean that we're running on ARM64 architecture device.
if (processMachine == NativeMethods.IMAGE_FILE_MACHINE_UNKNOWN && nativeMachine == NativeMethods.IMAGE_FILE_MACHINE_ARM64)
// Not WOW64 — this is a native 64-bit process.
// On ARM64 OS, distinguish ARM64 native from x64 emulated via the PE header.
if (RuntimeInformation.OSArchitecture == Architecture.Arm64)
{
// To distinguish between ARM64 and x64 emulated on ARM64 we check the PE header of the current running executable.
if (IsArm64Executable(process.MainModule!.FileName))
{
return PlatformArchitecture.ARM64;
}
else
{
return PlatformArchitecture.X64;
}
}
else
{
return PlatformArchitecture.X64;
return IsArm64Executable(process.MainModule!.FileName)
? PlatformArchitecture.ARM64
: PlatformArchitecture.X64;
}

return PlatformArchitecture.X64;
}
catch
{
// At the moment we cannot log messages inside the Microsoft.TestPlatform.PlatformAbstractions.
// We did an attempt in https://github.com/microsoft/vstest/pull/3422 - 17.2.0-preview-20220301-01 - but we reverted after
// because we broke a scenario where for .NET Framework application inside the test host
// we loaded runner version of Microsoft.TestPlatform.PlatformAbstractions but newer version Microsoft.TestPlatform.ObjectModel(the one close
// to the test container) and the old PlatformAbstractions doesn't contain the methods expected by the new ObjectModel throwing
// a MissedMethodException.

if (!Environment.Is64BitOperatingSystem)
{
// When we know this is not 64-bit operating system, then all processes are running as 32-bit, both
// the current process and other processes.
return PlatformArchitecture.X86;
}

try
{
var isWow64Process = NativeMethods.IsWow64Process(process.Handle, out var isWow64);
if (!isWow64Process)
{
// Do nothing we cannot log errors here.
}

// The process is running using WOW64, which suggests it is 32-bit (or any of the other machines, that we cannot
// handle, so we just assume x86). If it is not wow, we assume x64, because we failed the call to more advanced api
// that can tell us if this is arm64, so we are probably on older version of OS which is x64.
// We could call PlatformArchitecture.Architecture, but that uses the same api that we just failed to invoke.
return isWow64 ? PlatformArchitecture.X86 : PlatformArchitecture.X64;
}
catch
{
// We are on 64-bit system, let's assume x64 when we fail to determine the value.
return PlatformArchitecture.X64;
}
// We are on 64-bit system, let's assume x64 when we fail to determine the value.
return PlatformArchitecture.X64;
}
}

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