Signature parsing and GetFieldDescData cDAC API by rcj1 · Pull Request #119417 · dotnet/runtime

rcj1 · 2025-09-05T22:37:11Z

Adding SignatureDecoder contract (currently an abstraction over System.Reflection.Metadata SignatureDecoder with an implementation of SignatureTypeProvider.
Adding GetFieldDescData cDAC API and required helpers

Copilot

Pull Request Overview

This PR adds signature decoding capabilities to the cDAC (Compact Data Access Component) by implementing a new SignatureDecoder contract and the GetFieldDescData API. The implementation leverages System.Reflection.Metadata for signature decoding with a custom SignatureTypeProvider.

Key Changes

Adds SignatureDecoder contract with field signature decoding capability
Implements GetFieldDescData cDAC API for retrieving field descriptor information
Adds required data structures and helper methods for field descriptor access

Reviewed Changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
SOSDacImpl.cs	Implements GetFieldDescData with signature decoding and field information extraction
ISOSDacInterface.cs	Defines DacpFieldDescData structure and updates interface signature
SignatureDecoder_1.cs	Core signature decoder implementation using System.Reflection.Metadata
SignatureTypeProvider.cs	Custom type provider for signature decoding with runtime type system integration
RuntimeTypeSystem_1.cs	Adds field descriptor APIs and GetMethodTable implementation
Various data/contract files	Adds new data structures, constants, and contract registrations

...cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/SignatureDecoderFactory.cs

...rosoft.Diagnostics.DataContractReader.Contracts/Contracts/Signature/SignatureTypeProvider.cs

.../managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/EcmaMetadata_1.cs

src/native/managed/cdac/mscordaccore_universal/Legacy/ISOSDacInterface.cs

dotnet-policy-service · 2025-09-05T22:38:10Z

Tagging subscribers to this area: @steveisok, @dotnet/dotnet-diag
See info in area-owners.md if you want to be subscribed.

src/coreclr/vm/field.h

…nterface.cs Co-authored-by: Copilot <[email protected]>

docs/design/datacontracts/SignatureDecoder.md

docs/design/datacontracts/RuntimeTypeSystem.md

docs/design/datacontracts/SignatureDecoder.md

...ged/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/RuntimeTypeSystem_1.cs

src/native/managed/cdac/mscordaccore_universal/Legacy/SOSDacImpl.cs

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/EcmaMetadataUtils.cs

src/native/managed/cdac/mscordaccore_universal/Legacy/ISOSDacInterface.cs

docs/design/datacontracts/RuntimeTypeSystem.md

...aged/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/SignatureDecoder_1.cs

...rosoft.Diagnostics.DataContractReader.Contracts/Contracts/Signature/SignatureTypeProvider.cs

...aged/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/SignatureDecoder_1.cs

rcj1 · 2025-09-12T05:06:48Z

#119625 (comment)

docs/design/datacontracts/SignatureDecoder.md

...ged/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/RuntimeTypeSystem_1.cs

docs/design/datacontracts/RuntimeTypeSystem.md

...ged/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/RuntimeTypeSystem_1.cs

src/native/managed/cdac/mscordaccore_universal/Legacy/ISOSDacInterface.cs

.../managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/EcmaMetadata_1.cs

src/native/managed/cdac/mscordaccore_universal/Legacy/SOSDacImpl.cs

...ged/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/RuntimeTypeSystem_1.cs

Co-authored-by: Max Charlamb <[email protected]>

...ged/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/RuntimeTypeSystem_1.cs

docs/design/datacontracts/SignatureDecoder.md

src/coreclr/vm/datadescriptor/contracts.jsonc

src/coreclr/vm/field.h

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Constants.cs

src/native/managed/cdac/mscordaccore_universal/Legacy/TypeNameBuilder.cs

...anaged/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/IEcmaMetadata.cs

.../managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/EcmaMetadata_1.cs

...ed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/ISignatureDecoder.cs

...rosoft.Diagnostics.DataContractReader.Contracts/Contracts/Signature/SignatureTypeProvider.cs

docs/design/datacontracts/SignatureDecoder.md

rcj1 · 2025-09-23T00:17:47Z

We are using the CorElementType defined in the RuntimeTypeSystem abstraction as our CorElementType in the ISOS interface and in the cDAC APIs. This contains two internal types. We should expose these in a cleaner way; that is out of scope for this PR and I have created an issue for it
#119971

noahfalk

LGTM

I agree that an O(n) search for generic types may not be fast enough to ship the scenario but I don't think it needs to block this specific PR. I suspect we may want to upgrade it to a hashed lookup in the future.

rcj1 · 2025-09-23T06:51:07Z

LGTM

I agree that an O(n) search for generic types may not be fast enough to ship the scenario but I don't think it needs to block this specific PR. I suspect we may want to upgrade it to a hashed lookup in the future.

I can open up a tracking issue for this; I gathered that this is a more lengthy discussion of how to port this specific hash (if at all) from the runtime to the cDAC while minimizing the complexity of runtime internal involved, and there out of scope for this specific PR.

jkotas · 2025-09-23T12:53:25Z

I can open up a tracking issue for this;

Yes, we should have a tracking issue for this.

rcj1 · 2025-09-23T17:10:44Z

I can open up a tracking issue for this;

Yes, we should have a tracking issue for this.

Done
#120008

signature parsing and GetFieldDescData cDAC API

1b47b26

Copilot AI review requested due to automatic review settings September 5, 2025 22:37

github-actions bot added the area-Diagnostics-coreclr label Sep 5, 2025

Merge branch 'main' into Signature

61c3aae

dotnet-policy-service bot assigned rcj1 Sep 5, 2025

Copilot AI reviewed Sep 5, 2025

View reviewed changes

rcj1 commented Sep 5, 2025

View reviewed changes

src/coreclr/vm/field.h Outdated Show resolved Hide resolved

rcj1 requested review from davidwrighton, jkotas, max-charlamb and noahfalk September 5, 2025 22:40

rcj1 and others added 3 commits September 5, 2025 15:41

Fix missing newline at end of contracts.jsonc

bbc99bc

Update src/native/managed/cdac/mscordaccore_universal/Legacy/ISOSDacI…

14d4631

…nterface.cs Co-authored-by: Copilot <[email protected]>

fix

387207c

build-analysis bot mentioned this pull request Sep 6, 2025

Host Activation test failures on OSX: exit code 0x86 (134) #118904

Closed

jkotas reviewed Sep 7, 2025

View reviewed changes

docs/design/datacontracts/SignatureDecoder.md Outdated Show resolved Hide resolved

noahfalk reviewed Sep 10, 2025

View reviewed changes

max-charlamb reviewed Sep 10, 2025

View reviewed changes

rcj1 added 2 commits September 11, 2025 22:10

code review

7917e1b

Update SignatureDecoder.md

00c25b5

jkotas reviewed Sep 12, 2025

View reviewed changes

docs/design/datacontracts/SignatureDecoder.md Outdated Show resolved Hide resolved

max-charlamb mentioned this pull request Sep 12, 2025

Removing conversion from typehandle to methodtable #119625

Closed

rcj1 added 3 commits September 12, 2025 10:25

code review

b1f541e

Merge branch 'main' into Signature

7efa776

fix bad merge

6b1dc39

This was referenced Sep 12, 2025

LibraryImportGenerator.Unit.Tests crashing on linux-x64 mono interpreter #100800

Open

/root/helix/work/correlation/scripts/<hash>/execute.sh: Permission denied dotnet/dnceng#3412

Open

jkotas reviewed Sep 13, 2025

View reviewed changes

...ged/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/RuntimeTypeSystem_1.cs Outdated Show resolved Hide resolved

jkotas reviewed Sep 13, 2025

View reviewed changes

...ged/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/RuntimeTypeSystem_1.cs Show resolved Hide resolved

rcj1 added 5 commits September 13, 2025 11:09

fixing custom modifiers and not-founds

f38a02a

cache and renaming

b6a8e71

loadlevel

538ba6f

e

c51cfbf

Merge branch 'main' into Signature

fc947e0

max-charlamb reviewed Sep 16, 2025

View reviewed changes

rcj1 and others added 3 commits September 16, 2025 13:09

Apply suggestions from code review

17c4634

Co-authored-by: Max Charlamb <[email protected]>

code review

434bfad

Merge branch 'main' into Signature

9023b01

build-analysis bot mentioned this pull request Sep 17, 2025

"We stopped hearing from agent Azure Pipelines 32. Verify the agent machine is running and has a healthy network connection" dotnet/dnceng#1886

Open

3 tasks

max-charlamb reviewed Sep 17, 2025

View reviewed changes

max-charlamb reviewed Sep 18, 2025

View reviewed changes

...rosoft.Diagnostics.DataContractReader.Contracts/Contracts/Signature/SignatureTypeProvider.cs Outdated Show resolved Hide resolved

docs/design/datacontracts/SignatureDecoder.md Outdated Show resolved Hide resolved

rcj1 added 4 commits September 22, 2025 13:09

codereview

cfd962c

merge

6c326e1

small edits

13e30e1

Update src/coreclr/vm/datadescriptor/datadescriptor.inc

2cfa600

rcj1 mentioned this pull request Sep 22, 2025

[cDAC] Support APIs used by SOS #117782

Open

32 tasks

build-analysis bot mentioned this pull request Sep 23, 2025

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

Open

3 tasks

noahfalk approved these changes Sep 23, 2025

View reviewed changes

rcj1 merged commit c0a9bac into dotnet:main Sep 23, 2025
100 of 102 checks passed

rcj1 deleted the Signature branch September 23, 2025 06:55

github-actions bot locked and limited conversation to collaborators Oct 24, 2025

Conversation

rcj1 commented Sep 5, 2025

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull Request Overview

Key Changes

Reviewed Changes

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

dotnet-policy-service bot commented Sep 5, 2025

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

rcj1 commented Sep 12, 2025

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

rcj1 commented Sep 23, 2025

Uh oh!

noahfalk left a comment

Choose a reason for hiding this comment

Uh oh!

rcj1 commented Sep 23, 2025

Uh oh!

Uh oh!

jkotas commented Sep 23, 2025

Uh oh!

rcj1 commented Sep 23, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

6 participants