[cDAC] Implement EnumerateMonitorEventWaitList for cDAC#129054
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barosiak wants to merge 2 commits into
Open
[cDAC] Implement EnumerateMonitorEventWaitList for cDAC#129054barosiak wants to merge 2 commits into
barosiak wants to merge 2 commits into
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Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag |
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Pull request overview
Implements DacDbiImpl.EnumerateMonitorEventWaitList in the cDAC managed DacDbiImpl to enumerate threads waiting on a monitor’s condition wait list for a given object, and adds unit tests exercising key scenarios across architectures.
Changes:
- Added a cDAC implementation of
EnumerateMonitorEventWaitListthat reads theMonitor.s_conditionTable, resolves the object’sConditionviaConditionalWeakTable, maps per-thread waiter objects to threads, then walks the waiters linked list to invoke the callback. - Added
#if DEBUGvalidation comparing cDAC results against legacy DAC results. - Added unit tests covering: no sync block, null callback, missing condition / empty waiters list, and single/multiple/non-waiting thread cases.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/Dbi/DacDbiImpl.cs |
Adds the cDAC implementation of EnumerateMonitorEventWaitList plus DEBUG-only legacy cross-validation. |
src/native/managed/cdac/tests/UnitTests/DacDbiImplTests.cs |
Adds helper infrastructure and new tests for EnumerateMonitorEventWaitList behavior across architectures. |
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
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| // Build a map of Waiter objects to their owning Threads. | ||
| var waiterToThreadMap = new Dictionary<ulong, TargetPointer>(); | ||
| Contracts.IThread threadContract = _target.Contracts.Thread; | ||
| Contracts.ThreadStoreData threadStore = threadContract.GetThreadStoreData(); | ||
| TargetPointer currentThread = threadStore.FirstThread; | ||
| while (currentThread != TargetPointer.Null) | ||
| { | ||
| Contracts.ThreadData threadData = threadContract.GetThreadData(currentThread); | ||
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| if (_target.Contracts.ManagedTypeSource.TryGetThreadStaticFieldAddress( | ||
| "System.Threading.Condition", "t_waiterForCurrentThread", currentThread, out TargetPointer waiterSlot)) | ||
| { | ||
| TargetPointer waiterObj = _target.ReadPointer(waiterSlot); | ||
| if (waiterObj != TargetPointer.Null) |
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| var slotFragment = allocator.Allocate((ulong)ptrSize, $"WaiterSlot_{thread.Value:x}"); | ||
| helpers.WritePointer(slotFragment.Data, waiterFragments[waiterIdx].Address); | ||
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| TargetPointer outAddr = new(slotFragment.Address); | ||
| mockMts.Setup(m => m.TryGetThreadStaticFieldAddress( | ||
| "System.Threading.Condition", "t_waiterForCurrentThread", thread, out outAddr)) | ||
| .Returns(true); | ||
| waiterIdx++; |
max-charlamb
reviewed
Jun 8, 2026
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| if (_legacy is not null && fpCallback != 0) | ||
| List<ulong> dacThreads = new(); |
max-charlamb
reviewed
Jun 8, 2026
| // no sync block means no wait list | ||
| if (syncBlock != TargetPointer.Null | ||
| && _target.Contracts.ManagedTypeSource.TryGetStaticFieldAddress( | ||
| "System.Threading.Monitor", "s_conditionTable", out TargetPointer conditionTableSlot)) |
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Wondering if we should put this in a contract to allow it to be versioned.
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Summary
Implement
DacDbiImpl.EnumerateMonitorEventWaitListin the cDAC to enumerate threads waiting on a monitor lock for a given object.Changes
DacDbiImpl.cs- ImplementEnumerateMonitorEventWaitListwith#if DEBUGlegacy validationDacDbiImplTests.cs- Add 4 test methods (16 cases across architectures) covering no sync block, null callback, ConditionalWeakTable miss/empty list, and single/multiple/non-waiting thread scenarios