Remove async method inlining restrictions in crossgen2 by jtschuster · Pull Request #125472 · dotnet/runtime

jtschuster · 2026-03-12T01:43:47Z

Remove restrictions that prevented async methods from being inlined during ReadyToRun compilation.

All 69 async tests pass with both crossgen2 and composite R2R.

Output of the src/tests/async/execution-context/execution-context.cs was validated manually to ensure inlining is happening for async calls to methods without awaits. In Test(), these two calls were inlined as expected.

runtime/src/tests/async/execution-context/execution-context.cs

Lines 110 to 121 in b797348

    
           [MethodImpl(MethodImplOptions.AggressiveInlining)] 
        
           private static async Task ChangeThenThrowInlined() 
        
           { 
        
               s_local.Value = 123; 
        
               throw new Exception(); 
        
           } 
        
           [MethodImpl(MethodImplOptions.AggressiveInlining)] 
        
           private static async Task ChangeThenReturnInlined() 
        
           { 
        
               s_local.Value = 123; 
        
           }

Fixes #124665

Remove four restrictions that prevented async methods from being inlined during ReadyToRun compilation: 1. CanInline() rejected IsAsyncThunk()/IsAsyncCall() callees 2. CrossModuleInlineableUncached() rejected async variants/thunks 3. reportInlining() threw when async methods were cross-module inlined 4. InliningInfoNode skipped recording inlining info for async thunks All 69 async tests pass with both crossgen2 and composite R2R modes. Fixes dotnet#124665 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

jtschuster · 2026-03-12T01:44:06Z

/azp run runtime-coreclr crossgen2

azure-pipelines · 2026-03-12T01:44:32Z

Azure Pipelines successfully started running 1 pipeline(s).

Copilot

Pull request overview

Removes restrictions that prevented async methods from being inlined during ReadyToRun (crossgen2) compilation, fixing #124665.

Changes:

Removed four separate guards that blocked inlining of async methods (thunks, variants, calls) in R2R compilation.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
CorInfoImpl.ReadyToRun.cs	Removed exception throw for async method inlining
ReadyToRunCompilationModuleGroupBase.cs	Removed cross-module inlining restriction for async methods
ReadyToRunCodegenCompilation.cs	Removed `CanInline` restriction for async thunks/calls
InliningInfoNode.cs	Removed skip of async thunks in inlining info emission

jtschuster · 2026-03-16T20:06:17Z

/azp run runtime-coreclr crossgen2

azure-pipelines · 2026-03-16T20:06:32Z

Azure Pipelines successfully started running 1 pipeline(s).

Copilot

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated no new comments.

jtschuster · 2026-03-18T16:52:26Z

/azp run runtime-coreclr crossgen2

azure-pipelines · 2026-03-18T16:52:50Z

Azure Pipelines successfully started running 1 pipeline(s).

…sync

When crossgen2 emits CHECK_IL_BODY fixups for cross-module inlined async methods (miAsync), the runtime crashes with a MayHaveILHeader() precondition failure. This happens because the runtime marks the original MethodDesc as an async thunk, and MayHaveILHeader() returns false for thunks. However, the IL bytes are still present at the method's RVA in the PE. Runtime fix: Add GetILHeaderForStandaloneMetadata() helper that bypasses MayHaveILHeader() for async thunk methods by accessing the IL directly via Module::GetIL(GetRVA()). Crossgen2 fix: Separate ILBodyFixupSignature into _ilMethod (EcmaMethod for IL body hash computation) and _signatureMethod (MethodDesc for method identity encoding), making the different roles explicit. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Split GetModuleToken into GetILModuleToken (for IL hash and fixup module context) and GetSignatureModuleToken (for method identity encoding). Use _signatureMethod.GetTypicalMethodDefinition() for EmitMethodSignature so the correct method identity is encoded when IL source and signature method differ (e.g. runtime-async inlinees). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

The IL and signature methods always resolve to the same module token, so a single GetModuleToken suffices. Add Debug.Assert that signatureMethod.GetPrimaryMethodDesc() == ilMethod to enforce the invariant that both refer to the same underlying EcmaMethod. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…gnature is created

Copilot

Pull request overview

Copilot reviewed 15 out of 15 changed files in this pull request and generated 2 comments.

src/tests/readytorun/async-inline-thunks/async-inline-thunks.csproj

src/tests/readytorun/async-inline-thunks/helper/helper.csproj

In order to resolve the async method (which has a non-thunk IL body) from the CheckILBody fixup, separate out the signature MethodDesc from the IL providing MethodDesc inf ILBodyFixupSignature. The IL is retrieved for the EcmaMethod resolved from the _signatureMethod.GetPrimaryMethodDesc(), which is always an EcmaMethod for the TypicalMethodDefinitions allowed. At runtime, the correct method is resolved and the IL body is properly validated.

…sync

Copilot

Pull request overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated 3 comments.

src/tests/readytorun/async-inline-thunks/helper/helper.cs

src/tests/readytorun/async-inline-thunks/async-inline-thunks.cs

...ols/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/ILBodyFixupSignature.cs

jtschuster · 2026-03-31T20:55:07Z

/azp run runtime-coreclr crossgen2

azure-pipelines · 2026-03-31T20:55:26Z

Azure Pipelines successfully started running 1 pipeline(s).

Remove restrictions that prevented async methods from being inlined during ReadyToRun compilation. All 69 async tests pass with both crossgen2 and composite R2R. Output of the src/tests/async/execution-context/execution-context.cs was validated manually to ensure inlining is happening for async calls to methods without awaits. In `Test()`, these two calls were inlined as expected. https://github.com/dotnet/runtime/blob/b7973489277b74bc5da9d36a0a2883eaa987328f/src/tests/async/execution-context/execution-context.cs#L110-L121 Fixes dotnet#124665 --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings March 12, 2026 01:43

github-actions bot added the area-crossgen label Mar 12, 2026

dotnet-policy-service bot assigned jtschuster Mar 12, 2026

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Merge branch 'main' into InlineAsync

1cd97cf

This was referenced Mar 13, 2026

iOS.Device test WorkItemExecutions #122874

Closed

XHarness package install failure on iOS due to devicectl NSPOSIXErrorDomain error 49 #123796

Open

AOT precompile failed on ios-arm64: 'No space left on device' (exit code 1) #125107

Closed

Merge branch 'main' into InlineAsync

e6796ba

Copilot AI review requested due to automatic review settings March 16, 2026 20:06

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build-analysis bot mentioned this pull request Mar 17, 2026

BackgroundService_MultipleExceptions_ThrowsAggregateException is racy #125589

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build-analysis bot mentioned this pull request Mar 19, 2026

osx builds failing with CMake error #125757

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jtschuster requested review from MichalStrehovsky, davidwrighton and elinor-fung March 20, 2026 17:51

jtschuster and others added 7 commits March 26, 2026 17:21

Merge branch 'main' of https://github.com/dotnet/runtime into InlineA…

f15732e

…sync

Add comments explaining IL/signature method split for async fixups

febd446

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Undo changes to runtime

7b11660

Add SignatureMethod to ILBodyFixupSignature to control what method si…

00578a2

…gnature is created

Copilot AI review requested due to automatic review settings March 27, 2026 21:28

Copilot started reviewing on behalf of jtschuster March 27, 2026 21:29 View session

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src/tests/readytorun/async-inline-thunks/async-inline-thunks.csproj Show resolved Hide resolved

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build-analysis bot mentioned this pull request Mar 28, 2026

modpowTest.FastReducer_AssertFailure_RegressionTest hanging/timing out #126212

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jtschuster added 2 commits March 30, 2026 16:34

Merge branch 'main' of https://github.com/dotnet/runtime into InlineA…

e983977

…sync

Copilot AI review requested due to automatic review settings March 31, 2026 05:25

Copilot started reviewing on behalf of jtschuster March 31, 2026 05:26 View session

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jtschuster requested a review from davidwrighton April 2, 2026 18:03

davidwrighton approved these changes Apr 3, 2026

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jtschuster merged commit 10075f0 into dotnet:main Apr 6, 2026
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dotnet-maestro bot mentioned this pull request Apr 8, 2026

[main] Source code updates from dotnet/runtime dotnet/dotnet#5926

Merged

	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	private static async Task ChangeThenThrowInlined()
	{
	s_local.Value = 123;
	throw new Exception();
	}

	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	private static async Task ChangeThenReturnInlined()
	{
	s_local.Value = 123;
	}

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