Add opt-in support for GeneratedComInterface/ComImport RCW interop #87583

jkoritzinsky · 2023-06-14T23:37:12Z

Add opt-in support for casting a source-generated COM object wrapper to a [ComImport]-attributed interface. This support is opt-in only and not compatible with trimming or AOT and will never be so as it needs to use System.Reflection.Emit and it is interoperating with runtime-based COM, neither of which are AOT compatible and one of which is not trimming compatible at all.

The trimming test validates that the support for integrating with ComImport is fully trimmed away when the feature flag is not set.

TODO/Help wanted:

We need a property name for the .NET SDK for enabling this feature flag as we also want the analyzers for casting between ComImport and GeneratedComInterface types to not fire when this feature flag is on in the project.
I want to confirm that we have this configured such that the default experience in the .NET SDK is to trim away all of this code.
Do we need a "Native AOT App" test to validate the trimming behavior for NativeAOT as well, or is the existing test good enough?

cc: @dotnet/illink-contrib for the trimming test

Contributes to #87350

…erop

…mentation.

…ssues.

…erop support is trimmed away.

ghost · 2023-06-14T23:37:21Z

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Issue Details

Add opt-in support for casting a source-generated COM object wrapper to a [ComImport]-attributed interface. This support is opt-in only and not compatible with trimming or AOT and will never be so as it needs to use System.Reflection.Emit and it is interoperating with runtime-based COM, neither of which are AOT compatible and one of which is not trimming compatible at all.

The trimming test validates that the support for integrating with ComImport is fully trimmed away when the feature flag is not set.

TODO/Help wanted:

We need a property name for the .NET SDK for enabling this feature flag as we also want the analyzers for casting between ComImport and GeneratedComInterface types to not fire when this feature flag is on in the project.
I want to confirm that we have this configured such that the default experience in the .NET SDK is to trim away all of this code.
Do we need a "Native AOT App" test to validate the trimming behavior for NativeAOT as well, or is the existing test good enough?

cc: @dotnet/illink-contrib for the trimming test

Contributes to #87350

Author:	jkoritzinsky
Assignees:	-
Labels:	`area-System.Runtime.InteropServices`
Milestone:	-

...s/src/System/Runtime/InteropServices/Marshalling/ComImportInteropInterfaceDetailsStrategy.cs

...s/System.Runtime.InteropServices/src/System/Runtime/InteropServices/Marshalling/ComObject.cs

vitek-karas

The trim test looks good.
I'm a bit surprised we suppress trim analysis warnings in trim tests, but that's not in scope for this change.

vitek-karas · 2023-06-16T19:08:20Z

...e.InteropServices/src/System/Runtime/InteropServices/Marshalling/StrategyBasedComWrappers.cs

@@ -19,13 +20,12 @@ public class StrategyBasedComWrappers : ComWrappers

        protected static IIUnknownCacheStrategy CreateDefaultCacheStrategy() => new DefaultCaching();

+        [UnconditionalSuppressMessage("AOT", "IL3050:Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.", Justification = "The member with the attribute is in a IsDynamicCodeSupported block.")]


This is weird - you should not need this - you would need the pragma, but you should not need UnconditionalSuppressMessage - that means the feature switch is not working correctly for some reason.
Do you get warnings from trimmer/AOT compiler if the feature switch is off ?

Yep, I get the warning without applying it.

…update the trimming test to use the generated code for a better example of real-world trimming scenarios.

...s/src/System/Runtime/InteropServices/Marshalling/ComImportInteropInterfaceDetailsStrategy.cs

…e/InteropServices/Marshalling/ComImportInteropInterfaceDetailsStrategy.cs Co-authored-by: Jan Kotas <jkotas@microsoft.com>

AaronRobinsonMSFT

This LGTM, consider me signed off at present. I'll wait a bit for the other commenters before I mark "Approve".

elinor-fung · 2023-06-29T21:51:22Z

...s/System.Runtime.InteropServices/src/System/Runtime/InteropServices/Marshalling/ComObject.cs

    {
+        internal static bool BuiltInComSupported { get; } = AppContext.TryGetSwitch("System.Runtime.InteropServices.BuiltInComInterop.IsSupported", out bool supported) ? supported : true;


Could this use Marshal.IsBuiltInComSupported? That is implemented such that runtimes that don't support built-in COM at all return false regardless of the feature switch.

That API isn't exposed outside of CoreLib (we never made it public). I should be able to make it exposed enough for System.Runtime.InteropServices to see it I think without making it public if we would prefer.

...s/src/System/Runtime/InteropServices/Marshalling/ComImportInteropInterfaceDetailsStrategy.cs

jkotas

LGTM otherwise

jkotas · 2023-07-17T09:21:58Z

...s/src/System/Runtime/InteropServices/Marshalling/ComImportInteropInterfaceDetailsStrategy.cs

+namespace System.Runtime.InteropServices.Marshalling
+{
+    /// <summary>
+    /// An interface details strategy that enables discovering both interfaces defined with source-generated COM (i.e. <see cref="GeneratedComInterfaceAttribute"/> and <see cref="IUnknownDerivedAttribute{T, TImpl}"/>) and runtime-implemented COM (i.e. <see cref="ComImportAttribute"/>).


Suggested change

/// An interface details strategy that enables discovering both interfaces defined with source-generated COM (i.e. <see cref="GeneratedComInterfaceAttribute"/> and <see cref="IUnknownDerivedAttribute{T, TImpl}"/>) and runtime-implemented COM (i.e. <see cref="ComImportAttribute"/>).

/// An interface details strategy that enables discovering both interfaces defined with source-generated COM (i.e. <see cref="GeneratedComInterfaceAttribute"/> and <see cref="IUnknownDerivedAttribute{T, TImpl}"/>) and built-in COM (i.e. <see cref="ComImportAttribute"/>).

jkotas · 2023-07-17T09:22:14Z

...s/src/System/Runtime/InteropServices/Marshalling/ComImportInteropInterfaceDetailsStrategy.cs

+    /// An interface details strategy that enables discovering both interfaces defined with source-generated COM (i.e. <see cref="GeneratedComInterfaceAttribute"/> and <see cref="IUnknownDerivedAttribute{T, TImpl}"/>) and runtime-implemented COM (i.e. <see cref="ComImportAttribute"/>).
+    /// </summary>
+    /// <remarks>
+    /// This strategy is meant for intermediary adoption scenarios and is not compatible with trimming or NativeAOT by design. Since runtime-implemented COM is not trim friendly or AOT-compatible, these restrictions are okay.


Suggested change

/// This strategy is meant for intermediary adoption scenarios and is not compatible with trimming or NativeAOT by design. Since runtime-implemented COM is not trim friendly or AOT-compatible, these restrictions are okay.

/// This strategy is meant for intermediary adoption scenarios and is not compatible with trimming or NativeAOT by design. Since built-in COM is not trim friendly or AOT-compatible, these restrictions are okay.

(not commenting on all of these)

...s/src/System/Runtime/InteropServices/Marshalling/ComImportInteropInterfaceDetailsStrategy.cs

jkotas · 2023-07-17T09:36:36Z

...s/System.Runtime.InteropServices/src/System/Runtime/InteropServices/Marshalling/ComObject.cs

+
+        object ComImportInteropInterfaceDetailsStrategy.IComImportAdapter.GetRuntimeCallableWrapper()
+        {
+            return _runtimeCallableWrapper!;


Suggested change

return _runtimeCallableWrapper!;

Debug.Assert(_runtimeCallableWrapper != null);

return _runtimeCallableWrapper;

Is this guaranteed to be non-zero when this method is called? If it is the case, Debug.Assert would be better than !.

jkotas · 2023-07-17T09:42:55Z

...s/src/System/Runtime/InteropServices/Marshalling/ComImportInteropInterfaceDetailsStrategy.cs

+
+            Type implementationType = _forwarderInterfaceCache.GetValue(runtimeType, runtimeType =>
+            {
+                AssemblyBuilder assembly = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName("ComImportForwarder"), AssemblyBuilderAccess.RunAndCollect);


Suggested change

AssemblyBuilder assembly = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName("ComImportForwarder"), AssemblyBuilderAccess.RunAndCollect);

AssemblyBuilder assembly = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName("ComImportForwarder"), runtimeType.IsCollectible ? AssemblyBuilderAccess.RunAndCollect : AssemblyBuilderAccess.Run);

This should reduce the overhead quite a bit for typical non-collectible use case.

jkoritzinsky · 2023-07-18T20:27:32Z

Failures are known

jkoritzinsky added 7 commits June 13, 2023 16:49

Add initial implementation of GeneratedComInterface/ComImport RCW int…

4c34ffb

…erop

Actually define the .override entry for the dynamically emitted imple…

34f4120

…mentation.

Interfaces don't have parents.

5500bde

Add basic test for the RCW interop scenario and fix various IL emit i…

bb808ac

…ssues.

Suppress a diagnostic that fixing would make the test useless.

9d09747

Add a linker test and a feature flag to ensure that the ComImport int…

971a2a5

…erop support is trimmed away.

Add negative test

dcd4402

jkoritzinsky added the area-System.Runtime.InteropServices label Jun 14, 2023

jkoritzinsky requested review from AaronRobinsonMSFT, jtschuster and elinor-fung June 14, 2023 23:37

ghost assigned jkoritzinsky Jun 14, 2023

build-analysis bot mentioned this pull request Jun 15, 2023

Tracking issue for CI build timeouts #76454

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jkotas reviewed Jun 15, 2023

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vitek-karas reviewed Jun 16, 2023

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PR feedback and fix build.

5406981

vitek-karas reviewed Jun 16, 2023

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Merge branch 'main' into com-adoption-configuration-rcw

b058b40

build-analysis bot mentioned this pull request Jun 20, 2023

[mono][dbg] EvaluateConstantValueUsingRuntimeEvaluate test crash on Chrome #87053

Closed

jkoritzinsky and others added 2 commits June 19, 2023 20:23

Update the trimming test project template to allow unsafe blocks and …

d0c0b3e

…update the trimming test to use the generated code for a better example of real-world trimming scenarios.

Merge branch 'main' into com-adoption-configuration-rcw

9e915fc

jkoritzinsky requested a review from vitek-karas June 21, 2023 23:27

runfoapp bot mentioned this pull request Jun 22, 2023

Infra improvements for Helix #68176

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agocke reviewed Jun 23, 2023

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jkotas reviewed Jun 23, 2023

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Update src/libraries/System.Runtime.InteropServices/src/System/Runtim…

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…e/InteropServices/Marshalling/ComImportInteropInterfaceDetailsStrategy.cs Co-authored-by: Jan Kotas <jkotas@microsoft.com>

jkoritzinsky requested a review from agocke June 26, 2023 22:05

AaronRobinsonMSFT reviewed Jun 28, 2023

View reviewed changes

Remove suppression and fix fallback for COM interop flag.

3124755

This was referenced Jun 28, 2023

Work item tests crash on OSX x64 Debug #87287

Closed

LibraryImportGenerator.Unit.Tests crashed in CI #87951

Closed

windows-x86 release MSBuild_CMake is failing #88172

Closed

jkoritzinsky added 2 commits June 29, 2023 09:41

Disable the warning with a pragma again for Vitek.

cc068b3

Merge branch 'main' into com-adoption-configuration-rcw

e680980

elinor-fung reviewed Jun 29, 2023

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Change back to an unconditional suppress to get the PR green again.

7f36032

jkoritzinsky requested review from jkotas and elinor-fung July 12, 2023 23:52

This was referenced Jul 13, 2023

File check failures in x64 jit tests #88783

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Timeout in Microsoft.Gen.OptionsValidation.Unit.Test.EmitterTest #88784

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jkoritzinsky added 2 commits July 13, 2023 12:06

Implement feedback on form factor attributes.

c42589d

Refactor strategy selection to avoid non-windows failures.

682ba71

jkoritzinsky requested a review from jkotas July 13, 2023 22:56

Redo how we set suppressions to make sure they always are "needed".

35f25a8

jkotas reviewed Jul 17, 2023

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PR feedback and handle custom modifiers.

3b5ae8b

AaronRobinsonMSFT approved these changes Jul 18, 2023

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jkoritzinsky merged commit 1deddde into dotnet:main Jul 18, 2023

jkoritzinsky deleted the com-adoption-configuration-rcw branch July 18, 2023 20:27

jkoritzinsky mentioned this pull request Jul 18, 2023

Add EnableGeneratedComInterfaceComImportInterop property to control the source-generated/built-in COM interop interaction feature switch. dotnet/sdk#34072

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Add opt-in support for GeneratedComInterface/ComImport RCW interop #87583

Add opt-in support for GeneratedComInterface/ComImport RCW interop #87583

jkoritzinsky commented Jun 14, 2023

ghost commented Jun 14, 2023

vitek-karas left a comment

vitek-karas Jun 16, 2023

jkoritzinsky Jun 16, 2023

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elinor-fung Jun 29, 2023

jkoritzinsky Jun 29, 2023

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jkotas Jul 17, 2023

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jkoritzinsky commented Jul 18, 2023

		@@ -19,13 +20,12 @@ public class StrategyBasedComWrappers : ComWrappers

		protected static IIUnknownCacheStrategy CreateDefaultCacheStrategy() => new DefaultCaching();

		[UnconditionalSuppressMessage("AOT", "IL3050:Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.", Justification = "The member with the attribute is in a IsDynamicCodeSupported block.")]

		{
		internal static bool BuiltInComSupported { get; } = AppContext.TryGetSwitch("System.Runtime.InteropServices.BuiltInComInterop.IsSupported", out bool supported) ? supported : true;

	/// An interface details strategy that enables discovering both interfaces defined with source-generated COM (i.e. <see cref="GeneratedComInterfaceAttribute"/> and <see cref="IUnknownDerivedAttribute{T, TImpl}"/>) and runtime-implemented COM (i.e. <see cref="ComImportAttribute"/>).
	/// An interface details strategy that enables discovering both interfaces defined with source-generated COM (i.e. <see cref="GeneratedComInterfaceAttribute"/> and <see cref="IUnknownDerivedAttribute{T, TImpl}"/>) and built-in COM (i.e. <see cref="ComImportAttribute"/>).

	/// This strategy is meant for intermediary adoption scenarios and is not compatible with trimming or NativeAOT by design. Since runtime-implemented COM is not trim friendly or AOT-compatible, these restrictions are okay.
	/// This strategy is meant for intermediary adoption scenarios and is not compatible with trimming or NativeAOT by design. Since built-in COM is not trim friendly or AOT-compatible, these restrictions are okay.

	return _runtimeCallableWrapper!;
	Debug.Assert(_runtimeCallableWrapper != null);
	return _runtimeCallableWrapper;

	AssemblyBuilder assembly = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName("ComImportForwarder"), AssemblyBuilderAccess.RunAndCollect);
	AssemblyBuilder assembly = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName("ComImportForwarder"), runtimeType.IsCollectible ? AssemblyBuilderAccess.RunAndCollect : AssemblyBuilderAccess.Run);

Add opt-in support for GeneratedComInterface/ComImport RCW interop #87583

Add opt-in support for GeneratedComInterface/ComImport RCW interop #87583

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jkoritzinsky commented Jul 18, 2023