Runtime-async Exception.ToString() #122722

rcj1 · 2025-12-24T05:50:09Z

This PR implements exception stack trace collection in runtime-async stacks for both coreclr and nativeAOT.

Augmenting stack unwinding logic in AsyncHelpers.CoreCLR.cs to append frames from runtime-async async-await chain to exception stacktrace using DiagnosticIP of Continuation.
Implements ThrowExact helper to throw exception that has been stored in Continuation, while keeping its existing stack trace intact. Accomplished by creating throw helpers that set ExKind.RethrowFlag. Would be open to rename "RethrowFlag" and companions to "NoEraseFlag" or something similar, or leave as is.
ILC changes: Ensuring that stack trace records are emitted for runtime-async methods, and hidden for resumption stubs.
Testing: Added tests for line/method/document correctness including v1-v2 chaining.

@dotnet/ilc-contrib

- Add new JIT-EE API to report back debug information about the generated state machine and continuations - Refactor debug info storage on VM side to be more easily extensible. The new format has either a thin or fat header. The fat header is used when we have either uninstrumented bounds, patchpoint info, rich debug info or async debug info, and stores the blob sizes of all of those components in addition to the bounds and vars. - Add new async debug information to the storage on the VM side - Set get target method desc for async resumption stubs, to be used for mapping from continuations back to the async IL function that it will resume.

…mental APIs in async tests

…ostics

src/coreclr/vm/excep.cpp

jkotas · 2026-01-25T15:13:16Z

src/coreclr/vm/excep.cpp

+    _ASSERTE(IsException(pMT));
+
+    PTR_ThreadExceptionState pCurTES = pThread->GetExceptionState();
+    // Check if the flag indicating foreign exception raise has been setup or not,


@janvorli Could you please review these changes? In particular, the changes around IsRaisingForeignException flag for runtime async frames. Do we need to worry about it at all for runtime async frames?

I do not believe so. This flag is only set during ExceptionDispatchInfo.Throw(), so the only place it would matter is if Edi.Throw() is immediately above a runtime-async frame in a stacktrace. However, above a runtime-async frame we will either have another runtime-async frame, or DispatchContinuations, the only call site of this method.

rcj1 · 2026-01-25T18:41:19Z

/azp run runtime-nativeaot-outerloop

azure-pipelines · 2026-01-25T18:41:28Z

Azure Pipelines successfully started running 1 pipeline(s).

rcj1 · 2026-01-26T01:02:11Z

/azp run runtime-nativeaot-outerloop

azure-pipelines · 2026-01-26T01:02:25Z

Azure Pipelines successfully started running 1 pipeline(s).

jkotas · 2026-01-26T01:47:35Z

src/libraries/System.Diagnostics.StackTrace/tests/StackTraceTests.cs

        }
    }
+
+#if !(NATIVEAOT && !WINDOWS)


I doubt that this is going to work. The build of libraries partition is runtime flavor agnostic. The only place under libraries where you can use NATIVEAOT ifdef is CoreLib - that's because the CoreLib is not actually built from under libraries, but from runtime flavor specific location (e.g. src\coreclr\System.Private.CoreLib or src\coreclr\nativeaot\System.Private.CoreLib).

Building libraries tests for NativeAOT can be disabled at project granularity https://github.com/dotnet/runtime/blob/main/src/libraries/tests.proj#L401

rcj1 · 2026-01-26T02:01:15Z

/azp run runtime-nativeaot-outerloop

azure-pipelines · 2026-01-26T02:01:26Z

Azure Pipelines successfully started running 1 pipeline(s).

rcj1 · 2026-01-26T02:46:18Z

/azp run runtime-nativeaot-outerloop

azure-pipelines · 2026-01-26T02:46:27Z

Azure Pipelines successfully started running 1 pipeline(s).

src/coreclr/nativeaot/Runtime/amd64/ExceptionHandling.S

janvorli · 2026-01-26T16:22:45Z

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/StackTraceEmissionPolicy.cs

            if (method.HasCustomAttribute("System.Diagnostics", "StackTraceHiddenAttribute")
-                || (method.OwningType is MetadataType mdType && mdType.HasCustomAttribute("System.Diagnostics", "StackTraceHiddenAttribute")))
+                || (method.OwningType is MetadataType mdType && mdType.HasCustomAttribute("System.Diagnostics", "StackTraceHiddenAttribute"))
+                || (method is Internal.IL.Stubs.ILStubMethod)


I wonder why the IL stubs were not a problem before this change.

See #122722 (comment), they did show up as unknowns but this should filter them out.

janvorli · 2026-01-26T16:25:32Z

src/coreclr/vm/debugdebugger.cpp

+    _ASSERTE(pException != NULL);
+    // populate exception with information from the continuation object
+    EECodeInfo codeInfo((PCODE)diagnosticIP);
+    if (codeInfo.IsValid())


Is there a valid case when the codeInfo is not valid here? If not, it would be nice to add _ASSERTE here.

src/coreclr/vm/excep.cpp

janvorli · 2026-01-26T16:57:21Z

src/coreclr/vm/exkind.h

+#ifndef HAVE_EXKIND_H
+#define HAVE_EXKIND_H
+
+#include <cstdint>


Is seems that since you've moved it to the common.h, it is not needed here anymore, according to @am11's comment.

I thought that was just regarding <functional> @am11

src/coreclr/vm/excep.cpp

rcj1 · 2026-01-26T19:38:05Z

/azp run runtime-nativeaot-outerloop

azure-pipelines · 2026-01-26T19:38:23Z

Azure Pipelines successfully started running 1 pipeline(s).

janvorli · 2026-01-27T00:40:43Z

@rcj1 I am sorry, the C_FUNC wrapping should be done only for coreclr stuff, not for nativeAOT. I haven't realized we don't do that in the nativeaot asm code, it's been a long time since I worked on those parts.
Edit:
And also not for Windows.

This reverts commit 9159f0e.

rcj1 · 2026-01-27T13:36:48Z

/azp run runtime-nativeaot-outerloop

azure-pipelines · 2026-01-27T13:37:07Z

Azure Pipelines successfully started running 1 pipeline(s).

jakobbotsch and others added 30 commits October 1, 2025 14:54

Set target method desc for resumption stubs

b7bb968

Add JIT-EE boilerplate

d5d0864

Update managed view

6addd0e

Remove TODOs

6a5bf19

Leaf transition

262260a

Comment

4e2a829

Delete unused enum

820afa9

Restore comment

3621eae

Fix osx build

f597424

Fix GCC build

6bb6cee

Change sentinel value, fix contract

f580e3f

Bump R2R

55b9522

Clean up

c9c64be

Expose async debug info accessor APIs

db77446

Missed bumping R2R version for naot

c808390

Fix reverse mapping to IL local nums

3ec5160

Fix monotonicity for async vars

bb12c77

Code style

bf3364b

Fix JIT-EE prompt tools from Egor's instructions, allow use of experi…

b49f38f

…mental APIs in async tests

Address feedback, make comment less misleading

d1bf49f

Add AsyncContinuationVarInfo.GCIndex

579714e

Publish NextContinuation in TLS

c056793

Rename ThunkTask -> RuntimeAsyncTask

9679f91

testing

abd7d8b

Merge branch 'main' of github.com:dotnet/runtime into jit-async-diagn…

7a34475

…ostics

Report native offsets instead

e839409

Run jit-format

d8ad0c1

Print reported async debug info, always report it

9fdd8a7

exception tostring

1da796e

jkotas reviewed Jan 25, 2026

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jkotas reviewed Jan 25, 2026

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gc etc

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disable tests

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jkotas reviewed Jan 26, 2026

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disable tests

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janvorli reviewed Jan 26, 2026

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rcj1 added 4 commits January 26, 2026 10:14

code review

ed27783

code review

5481454

code review

040e2d0

code review

653d24a

code review

9159f0e

rcj1 added 2 commits January 26, 2026 18:15

Revert "code review"

b414505

This reverts commit 9159f0e.

Fix throw site IP retrieval in ExceptionHandling.asm

b139874

This was referenced Jan 27, 2026

Sometimes the helix SDK uses GetWorkItemsAsync when workitems aren't done processing. dotnet/dnceng#6011

Open

MSBuild AppleAppBuilderTask MSB4018 exceptions from unresolved arm64 Swift linker symbols on iOS arm64 release builds #122183

Open

Runtime-async Exception.ToString() #122722

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Runtime-async Exception.ToString() #122722

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