Replace MethodDescCallSite with UnmanagedCallersOnly in clrex.cpp by AaronRobinsonMSFT · Pull Request #126061 · dotnet/runtime

AaronRobinsonMSFT · 2026-03-24T23:03:01Z

Note

This PR description was generated with the assistance of GitHub Copilot.

Convert exception construction in clrex.cpp from MethodDescCallSite/CallDescrWorker to the UnmanagedCallersOnlyCaller pattern for EEArgumentException, EETypeLoadException, and EEFileLoadException.

Changes

Exception.CoreCLR.cs - Add [UnmanagedCallersOnly] CreateArgumentException factory method
FileLoadException.CoreCLR.cs - Add [UnmanagedCallersOnly] Create factory method
TypeLoadException.CoreCLR.cs - Add [UnmanagedCallersOnly] Create factory method
clrex.cpp - Replace MethodDescCallSite usage with UnmanagedCallersOnlyCaller in three CreateThrowable methods
corelib.h - Register new managed methods (METHOD__EXCEPTION__CREATE_ARGUMENT_EXCEPTION, METHOD__TYPE_LOAD_EXCEPTION__CREATE, METHOD__FILE_LOAD_EXCEPTION__CREATE)
metasig.h - Remove unused metasig entries (IM(Str_Int_RetVoid), IM(Str_Str_Str_Int_RetVoid))

Contributes to #123864

Convert EEArgumentException, EETypeLoadException, and EEFileLoadException CreateThrowable methods to use UnmanagedCallersOnlyCaller instead of MethodDescCallSite/CallDescrWorker for invoking managed exception constructors. Add corresponding [UnmanagedCallersOnly] factory methods in managed code and remove unused metasig entries. Contributes to dotnet#123864 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

This PR migrates several VM-to-managed exception construction paths in src/coreclr/vm/clrex.cpp from MethodDescCallSite / CallDescrWorker to the UnmanagedCallersOnlyCaller reverse P/Invoke pattern, adding the corresponding [UnmanagedCallersOnly] managed factory entrypoints and binder registrations in CoreLib.

Changes:

Add [UnmanagedCallersOnly] managed factory methods for ArgumentException, TypeLoadException, and FileLoadException construction.
Update clrex.cpp to invoke these factories via UnmanagedCallersOnlyCaller instead of MethodDescCallSite.
Register new CoreLib binder method IDs and remove now-unused metasig entries.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/coreclr/vm/metasig.h	Removes metasig entries no longer needed after dropping `MethodDescCallSite` ctor invocations.
src/coreclr/vm/corelib.h	Adds binder registrations for the new managed `[UnmanagedCallersOnly]` factory methods.
src/coreclr/vm/clrex.cpp	Switches three `CreateThrowable()` implementations to `UnmanagedCallersOnlyCaller`.
src/coreclr/System.Private.CoreLib/src/System/TypeLoadException.CoreCLR.cs	Adds `[UnmanagedCallersOnly] TypeLoadException.Create` factory.
src/coreclr/System.Private.CoreLib/src/System/IO/FileLoadException.CoreCLR.cs	Adds `[UnmanagedCallersOnly] FileLoadException.Create` factory.
src/coreclr/System.Private.CoreLib/src/System/Exception.CoreCLR.cs	Adds `[UnmanagedCallersOnly] Exception.CreateArgumentException` helper for ctor invocation.

src/coreclr/vm/clrex.cpp

src/coreclr/vm/corelib.h

src/coreclr/vm/clrex.cpp

src/coreclr/System.Private.CoreLib/src/System/TypeLoadException.CoreCLR.cs

src/coreclr/vm/clrex.cpp

src/coreclr/System.Private.CoreLib/src/System/Exception.CoreCLR.cs

Refactor EEFileLoadException::GetFileLoadKind to use a switch statement. Add ArgumentExceptionKind and FileLoadExceptionKind enums for managed mapping. Update CreateThrowable methods to use UnmanagedCallersOnlyCaller. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

jkotas · 2026-03-25T04:31:53Z

src/coreclr/System.Private.CoreLib/src/System/IO/FileLoadException.CoreCLR.cs

+                    FileLoadExceptionKind.FileLoad => new FileLoadException(fileName, hresult),
+                    _ => throw new InvalidOperationException()


Suggested change

FileLoadExceptionKind.FileLoad => new FileLoadException(fileName, hresult),

_ => throw new InvalidOperationException()

_ /* FileLoadExceptionKind.FileLoad */ => new FileLoadException(fileName, hresult),

jkotas · 2026-03-25T04:33:02Z

src/coreclr/System.Private.CoreLib/src/System/IO/FileLoadException.CoreCLR.cs

+            try
+            {
+                string? fileName = pFileName is not null ? new string(pFileName) : null;
+                *pThrowable = kind switch


Suggested change

*pThrowable = kind switch

Debug.Assert(Enum.IsDefined(kind));

*pThrowable = kind switch

jkotas · 2026-03-25T04:33:21Z

src/coreclr/System.Private.CoreLib/src/System/Exception.CoreCLR.cs

+
+                // Note that ArgumentException takes arguments to its constructor in a different order,
+                // for usability reasons.  However it is inconsistent with our other exceptions.
+                *pThrowable = kind switch


Suggested change

*pThrowable = kind switch

Debug.Assert(Enum.IsDefined(kind));

*pThrowable = kind switch

jkotas · 2026-03-25T04:34:02Z

src/coreclr/System.Private.CoreLib/src/System/Exception.CoreCLR.cs

+                    ArgumentExceptionKind.Argument => new ArgumentException(message, paramName),
+                    ArgumentExceptionKind.ArgumentNull => new ArgumentNullException(paramName, message),
+                    ArgumentExceptionKind.ArgumentOutOfRange => new ArgumentOutOfRangeException(paramName, message),
+                    _ => throw new InvalidOperationException()


Suggested change

ArgumentExceptionKind.Argument => new ArgumentException(message, paramName),

ArgumentExceptionKind.ArgumentNull => new ArgumentNullException(paramName, message),

ArgumentExceptionKind.ArgumentOutOfRange => new ArgumentOutOfRangeException(paramName, message),

_ => throw new InvalidOperationException()

ArgumentExceptionKind.ArgumentNull => new ArgumentNullException(paramName, message),

ArgumentExceptionKind.ArgumentOutOfRange => new ArgumentOutOfRangeException(paramName, message),

_ /* ArgumentExceptionKind.Argument */ => new ArgumentException(message, paramName)

jkotas · 2026-03-25T04:36:54Z

src/coreclr/System.Private.CoreLib/src/System/Exception.CoreCLR.cs

+                // Note that ArgumentException takes arguments to its constructor in a different order,
+                // for usability reasons.  However it is inconsistent with our other exceptions.


Suggested change

// Note that ArgumentException takes arguments to its constructor in a different order,

// for usability reasons. However it is inconsistent with our other exceptions.

I do not think we need this comment here

Copilot AI review requested due to automatic review settings March 24, 2026 23:03

github-actions bot added the area-ExceptionHandling-coreclr label Mar 24, 2026

dotnet-policy-service bot assigned AaronRobinsonMSFT Mar 24, 2026

github-project-automation bot added this to AppModel Mar 24, 2026

Copilot started reviewing on behalf of AaronRobinsonMSFT March 24, 2026 23:03 View session

AaronRobinsonMSFT mentioned this pull request Mar 24, 2026

Replace MethodDescCallSite instances with UnmanagedCallersOnlyAttribute pattern #123864

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AaronRobinsonMSFT requested review from jkoritzinsky and jkotas March 24, 2026 23:07

AaronRobinsonMSFT added this to the 11.0.0 milestone Mar 24, 2026

Copilot AI reviewed Mar 24, 2026

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jkotas approved these changes Mar 25, 2026

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Replace MethodDescCallSite with UnmanagedCallersOnly in clrex.cpp#126061

Replace MethodDescCallSite with UnmanagedCallersOnly in clrex.cpp#126061
AaronRobinsonMSFT wants to merge 2 commits intodotnet:mainfrom
AaronRobinsonMSFT:dev/arobins/clrex-uco-conversion

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		FileLoadExceptionKind.FileLoad => new FileLoadException(fileName, hresult),
		_ => throw new InvalidOperationException()

	FileLoadExceptionKind.FileLoad => new FileLoadException(fileName, hresult),
	_ => throw new InvalidOperationException()
	_ /* FileLoadExceptionKind.FileLoad */ => new FileLoadException(fileName, hresult),

	*pThrowable = kind switch
	Debug.Assert(Enum.IsDefined(kind));
	*pThrowable = kind switch

		// Note that ArgumentException takes arguments to its constructor in a different order,
		// for usability reasons. However it is inconsistent with our other exceptions.

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