Emit async method thunks in Native AOT #121565
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Pull Request Overview
This PR implements async method thunks in Native AOT by replacing a ThrowNotSupportedException placeholder with actual IL generation code in the EmitAsyncMethodThunk method. The implementation mirrors the existing CoreCLR VM C++ implementation to ensure consistency across runtimes.
Key Changes
- Removed the NotSupportedException throw and implemented full IL generation for async method thunks
- Added logic to handle both ValueTask and Task return types (generic and non-generic variants)
- Implemented instantiation handling for generic types and methods
- Added cross-reference comments between C++ and C# implementations
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| src/coreclr/vm/asyncthunks.cpp | Updated comment capitalization and added cross-reference comment to C# implementation |
| src/coreclr/tools/Common/TypeSystem/IL/Stubs/AsyncThunks.cs | Implemented full async method thunk IL generation matching CoreCLR VM behavior, handling ValueTask/Task paths with completion checking and awaiting logic |
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Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas |
This was referenced Nov 13, 2025
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This looks good to me, however the failure in the Checked leg is real. You'll need to wait for #121573 to clear it.
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The method matches EmitAsyncMethodThunk in CoreCLR.