[cDAC] Source generator for IData<T> data classes

[max-charlamb]

Note

This PR was prepared with assistance from GitHub Copilot.

Introduces a Roslyn incremental source generator (DataGenerator) for cDAC IData<T> data classes, and ports ~150 hand-written classes under Microsoft.Diagnostics.DataContractReader.Contracts/Data/ to the new attribute-driven form.

Builds on

• [cdac] Add IManagedTypeSource contract for FQN based type access #127310 — [cdac] Add IManagedTypeSource contract for FQN based type access. The first commit on this branch (Implement ManagedTypeSource contract) is that PR's work; this PR builds on top of it. The managed type source is needed for IData classes that use [CdacType(ManagedFullName = "...")] instead of a native descriptor.

Commits in this PR

1. [cDAC] Add IData<T> source-generator infrastructure — adds the DataGenerator project, the [CdacType]/[Field]/[FieldAddress]/[InstanceDataStart]/[FieldOffset]/[StaticAddress]/[StaticReference]/[ThreadStaticAddress] attributes, an OnInit partial hook, and a Write{Name} write-back path for [Field(Writable = true)]. No existing classes are converted; build remains green.
2. [cDAC] Convert IData<T> classes to source-generator form — ports ~150 IData classes to use the new attributes. Net diff is roughly -1300 lines.

Design notes

See docs/design/datacontracts/IData.md (added in commit 1) for the full attribute surface and the "good practices" guidance the conversions follow:

• Don't put logic in IData classes — declarative attributes only; use OnInit for things that don't fit.
• Don't eagerly dereference pointers to other IData classes — store as TargetPointer and let callers materialize, to avoid ambiguous null semantics. Inline structs ([Field(InPlace = true)]) are fine.
• One class, one descriptor.
• [Field(Writable = true)] properties must be declared { get; private set; } so the generated Write{Name} method can update the in-memory cache.

Intentional surface refinements

A handful of conversions go slightly beyond a mechanical port (also documented in IData.md):

• Thread.RuntimeThreadLocals — eager IData deref → lazy TargetPointer; Thread_1.cs materializes via ProcessedData.GetOrAdd.
• InteropSyncBlockInfo.{RCW,CCW,CCF,TaggedMemory} — always-non-null TargetPointer (with .Null sentinel) → nullable TargetPointer?; SyncBlock_1.cs updated.
• Thread.DebuggerControlledThreadState — now a real [Field(Writable = true)]; Set/Reset paths use the generated WriteDebuggerControlledThreadState against the cached Data.Thread.

Holdout

JITNotification is intentionally left hand-written; its mutable, count-driven layout doesn't map cleanly onto the current generator surface.

Test results

dotnet build cdac.slnx clean (0 warnings, 0 errors). All 2177 cDAC unit tests pass; 16 skipped (unchanged from main).

[Copilot]

Pull request overview

This PR introduces a Roslyn incremental source generator (DataGenerator) that emits IData<T>.Create factories, field accessors, managed-type lookups, and write-back methods from declarative attributes ([CdacType], [Field], [FieldAddress], [InstanceDataStart], [FieldOffset], [Static…], [ThreadStaticAddress]). It then mechanically converts ~150 hand-written IData<T> classes under Microsoft.Diagnostics.DataContractReader.Contracts/Data/ to the new attribute-driven form, removing ~1300 lines of boilerplate. The PR also depends on/includes the new IManagedTypeSource contract from #127310 and refactors callers (SyncBlock_1, Thread_1, Debugger_1, AuxiliarySymbols_1, dump tests) to use it.

Changes:

• New Microsoft.Diagnostics.DataContractReader.DataGenerator Roslyn analyzer project (Model, EquatableArray, generator entry, plus attribute/parser/emitter sources not all shown).
• Conversion of ~150 Data/* classes to [CdacType] + partial with attribute-driven member declarations and optional partial void OnInit hooks.
• Surface refinements: Thread.RuntimeThreadLocals becomes a lazy TargetPointer; InteropSyncBlockInfo.{RCW,CCW,CCF,TaggedMemory} become TargetPointer?; Debugger writable fields use [Field(Writable = true)] with generated Write{Name} methods; dump/SyncBlock_1/AuxiliarySymbols_1 updated to follow.

Reviewed changes

Copilot reviewed 183 out of 184 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
DataGenerator/*.cs, .csproj	New incremental generator project (model types, EquatableArray helper, IsExternalInit shim, generator entry point).
Contracts.csproj, cdac.slnx	Wire generator as analyzer; add generator project to solution.
Data/*.cs (~140 files)	Mechanical port to [CdacType] + partial class with [Field]/[FieldAddress]/[InstanceDataStart]/[FieldOffset] properties; some classes retain OnInit for non-declarative logic.
Data/Managed/*.cs	New per-managed-type wrappers (Lock, List, ComWrappers, NativeObjectWrapper, ConditionalWeakTable*) using ManagedFullName.
Data/AuxiliarySymbolInfo.cs	Address renamed to CodeAddress to avoid colliding with generator-emitted Address.
Data/Debugger.cs	SetField helper removed; writable fields use [Field(Writable = true)] and generated Write{Name}.
Data/InteropSyncBlockInfo.cs, Data/SyncBlock.cs	RCW/CCW/CCF/TaggedMemory become nullable; SyncBlock loses Address.
Contracts/Thread_1.cs	Materializes RuntimeThreadLocals lazily; handles new nullable ExceptionWatsonBucketTrackerBuckets / UEWatsonBucketTrackerBuckets.
Contracts/SyncBlock_1.cs	Uses Data.Managed.Lock + IManagedTypeSource instead of hand-rolled metadata walk; updated for nullable interop pointers.
Contracts/Debugger_1.cs, Contracts/AuxiliarySymbols_1.cs, CoreCLRContracts.cs	Switch to Write{Name} helpers; register ManagedTypeSource contract; rename to CodeAddress.
Abstractions/Contracts/IManagedTypeSource.cs, ContractRegistry.cs, IRuntimeTypeSystem.cs	New IManagedTypeSource contract; remove GetTypeByNameAndModule / GetCoreLibFieldDescAndDef from IRuntimeTypeSystem.
datadescriptor.inc	Register ManagedTypeSource contract version.
docs/design/datacontracts/ComWrappers.md	Doc updated to describe ManagedTypeSource-based lookups.
tests/DumpTests/*.cs	Replace rts.GetTypeByNameAndModule calls with IManagedTypeSource.GetTypeHandle/TryGetThreadStaticFieldAddress.

[Copilot]

Pull request overview

Copilot reviewed 184 out of 184 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 194 out of 194 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 194 out of 194 changed files in this pull request and generated no new comments.

[Copilot]

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Copilot reviewed 194 out of 194 changed files in this pull request and generated no new comments.

[noahfalk]

I see the PR still has distinct Data.Managed.* and Data.* types which implies we can't change a type's implementation between managed and native without also making a parallel (breaking) change to cDAC. Am I interpreting that right?

I think we want to have flexibility to shift between managed and native implementations without requiring a cDAC change. Do you think that is something we can amend this PR to do, or there are substantial challenges to being able to do that? I focus on this part first because I think the design decisions here will have a number of cascading effects.

As a concrete example I'm imagining two different versions of the runtime where one implements Lock as:

class Lock // C++
{
    private:
    int _state;
} 

Lock* g_pLockInstance;

And the other is:

namespace System.Runtime; // C#
class Lock
{
     private int _state;
     private static Lock s_lockInstance;
}

The goal would be that we are free to require anything in the runtime data descriptor we want to aid in the migration, but we could write the cDAC code targetting one of those shapes initially and switch to the other one without any of the debugging tools needing an update.

[max-charlamb]

Thanks for pointing this out. This is an oversight. The two different versions don't need to be seperated.

Here is a sample that makes lock work with both native and managed: max-charlamb@c9ce9363b38

[Copilot]

Pull request overview

Copilot reviewed 194 out of 194 changed files in this pull request and generated 4 comments.

[Copilot]

Pull request overview

Copilot reviewed 194 out of 194 changed files in this pull request and generated 6 comments.