[cDAC] save datadescriptors in minidumps#121360
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max-charlamb merged 7 commits intodotnet:mainfrom Dec 12, 2025
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November 4, 2025 18:48
max-charlamb
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hoyosjs,
noahfalk,
rcj1 and
steveisok
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Pull Request Overview
This PR adds enumeration support for cDAC (Contract-based DAC) data descriptors in minidumps. The main purpose is to ensure that cDAC contract descriptor data structures are included in minidump memory reports, making them available for debugging.
Key changes:
- Adds a new
EnumMemDataDescriptorsmethod that enumerates the main ContractDescriptor and its subdescriptors - Integrates the new enumeration into the minidump generation workflow
- Documents the ordering requirement for subdescriptor pointers in the global structure
Reviewed Changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
| src/coreclr/vm/datadescriptor/datadescriptor.inc | Adds a comment documenting that subdescriptor pointers must be the last pointers in the global structure |
| src/coreclr/debug/daccess/enummem.cpp | Implements EnumMemDataDescriptors to enumerate ContractDescriptor structures and integrates it into the minidump workflow |
| src/coreclr/debug/daccess/dacimpl.h | Declares the new EnumMemDataDescriptors method |
| src/coreclr/debug/daccess/CMakeLists.txt | Adds include directory for contract-descriptor.h header |
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hoyosjs
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Nov 6, 2025
noahfalk
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Nov 7, 2025
3 tasks
hoyosjs
approved these changes
Dec 2, 2025
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Saves datadescriptors json blobs in minidumps.
This enumeration algorithm is basic and hardcodes the number of sub-descriptors on the main datadescriptor. Fully recursing the subdescriptors the same way as the cDAC would require parsing the JSON blob. I believe this is fine for now and in the future, we'd move this code over to the cDAC where it is already parsed.
My biggest concern is bloating minidump file size when this won't be used in most scenarios for now.
Saving datadescriptors in Heap/Mini dumps takes around 10-15kB.