Make custom IData initializers lazy

[max-charlamb]

Summary

This changes custom IData initialization from one eager OnInit hook to named, per-property lazy initializer methods.

IData generation

• Add [CustomInit(nameof(Method))] for properties requiring custom read logic.
• Generate lazy property getters that invoke and memoize the named initializer on first access.
• Keep generated writable fields limited to [Field(Writable = true)] properties.
• Add a descriptor-only TableRW IData type so its generated GetSize method is used when indexing metadata tables.

Usage analysis

• Put DataDescriptorDependency and UsesDataDescriptorTypeSize annotations on custom initializer methods.
• Record declared initializer dependencies while continuing to analyze the initializer body for globals, helper calls, and nested IData property reads.
• Avoid treating EnsureAllFieldsRead as a complete dependency summary for types with custom initializers.

IData implementations

• Convert existing OnInit implementations to named per-property initializer methods.
• Preserve optional-field behavior and defer custom reads until the corresponding property is accessed.

Documentation and tests

• Document named custom initializers and method-level dependency annotations.
• Regenerate contract usage documentation to reflect property-level lazy reads.
• Add generator and usage-analysis coverage for lazy initialization, memoization, named methods, and combined declared/inferred dependencies.

Testing

• Microsoft.Diagnostics.DataContractReader.Contracts build
• DataGenerator.Tests: 46 passed
• CdacUsageGraph.Tests: 86 passed
• Usage.Tests: 4 passed
• Microsoft.Diagnostics.DataContractReader.Tests: 3207 passed, 16 skipped
• CdacUsageGraph docs --check

Note

This pull request description was generated with GitHub Copilot.

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[Copilot]

Pull request overview

Refactors cDAC IData custom initialization from a single eager OnInit hook to named, per-property lazy initializer methods (via a new [CustomInit] attribute), and updates the usage-analysis tooling/tests/docs accordingly.

Changes:

• Introduces [CustomInit(nameof(Method))] and generator support to emit lazy, memoized getters that call an author-provided initializer method.
• Updates CdacUsageGraph to treat initializer methods as dependency-bearing while still walking their bodies for inferred globals/helper/property reads.
• Converts many existing IData implementations (Contracts/Data) and updates design docs + generator/usage tests for the new model.

Reviewed changes

Copilot reviewed 48 out of 48 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/native/managed/cdac/tools/CdacUsageGraph/tests/CdacUsageGraph.Tests/UsageWalkerIntegrationTests.cs	Updates integration test to read deps from init methods
src/native/managed/cdac/tools/CdacUsageGraph/tests/CdacUsageGraph.Tests/DataTypeIndexTests.cs	Updates/extends usage-index tests for custom init behavior
src/native/managed/cdac/tools/CdacUsageGraph/src/CdacUsageGraph/Semantic/CdacAttributeMatcher.cs	Adds CustomInit symbol + custom-initializer detection
src/native/managed/cdac/tools/CdacUsageGraph/src/CdacUsageGraph/CdacSymbols.cs	Adds metadata name constant for CustomInitAttribute
src/native/managed/cdac/tools/CdacUsageGraph/src/CdacUsageGraph/Analysis/UsageWalker.cs	Avoids short-circuiting body analysis for custom init methods
src/native/managed/cdac/tests/DataGenerator/TestTypes.cs	Adds test type covering [CustomInit] generator behavior
src/native/managed/cdac/tests/DataGenerator/DataGeneratorTests.cs	Adds tests for laziness/memoization and dependency behavior
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/UnwindInfo.cs	Converts OnInit to per-property custom initializers
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/TypeDesc.cs	Converts OnInit to custom initializer returning base-derived value
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/Thread.cs	Splits eager init into per-property custom initializers
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/TableSegment.cs	Makes byte-buffer reads lazy via custom initializers
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/TableRW.cs	Adds descriptor-only type to surface generated GetSize
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/SyncTableEntry.cs	Converts pointer-following init logic to lazy initializers
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/SyncBlock.cs	Splits OnInit reads into per-property lazy initializers
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ReadyToRunInfo.cs	Converts multiple pointer computations to lazy initializers
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ReadyToRunCoreHeader.cs	Converts section list materialization to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/RCW.cs	Converts interface-entry list read to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/RangeSectionFragment.cs	Converts tag-bit stripping logic to custom initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/PrecodeMachineDescriptor.cs	Reworks optional fields/buffers into per-property lazy initializers
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ObjectHandle.cs	Splits handle/object computation into per-property initializers
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/InterpreterRealCodeHeader.cs	Converts pointer-following init logic to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/InstMethodHashTable.cs	Converts entry enumeration to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/HandleTableMap.cs	Converts bucket-pointer list read to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/Frames/HijackArgs.cs	Converts register map materialization to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/Frames/Frame.cs	Converts identifier read to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/Frames/CalleeSavedRegisters.cs	Converts register map materialization to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/Frames/ArgumentRegisters.cs	Converts register map materialization to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/EETypeHashTable.cs	Converts entry enumeration to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/DynamicStaticsInfo.cs	Splits masked-pointer reads into lazy initializers
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ComWrappersVtablePtrs.cs	Converts pointer list materialization to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ComInterfaceEntry.cs	Converts GUID materialization to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ComCallWrapper.cs	Converts interface pointer array read to lazy initializer
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/CMiniMdRW.cs	Uses TableRW.GetSize(target) via new descriptor-only type
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/Bucket.cs	Splits key/value array materialization into separate lazy initializers
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ArrayListBase.cs	Splits blocks vs element flattening into separate lazy initializers
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/CdacAttributes.cs	Adds new public [CustomInit] attribute definition
src/native/managed/cdac/IData.md	Updates spec to describe [CustomInit] replacing OnInit
src/native/managed/cdac/gen/Parser.cs	Parses [CustomInit]; refactors writable-field tracking
src/native/managed/cdac/gen/Model.cs	Adds CustomInit member kind; extends member model
src/native/managed/cdac/gen/Emitter.cs	Emits lazy getters that call named initializer methods
docs/design/datacontracts/WindowsErrorReporting.md	Regenerates “data descriptors used” (removals/updates)
docs/design/datacontracts/SyncBlock.md	Regenerates “data descriptors used” (removals/updates)
docs/design/datacontracts/StackWalk.md	Regenerates “data descriptors used” (removals/updates)
docs/design/datacontracts/RuntimeMutableTypeSystem.md	Regenerates “data descriptors used” (removals/updates)
docs/design/datacontracts/Object.md	Regenerates “data descriptors used” (removals/updates)
docs/design/datacontracts/ExecutionManager.md	Regenerates “data descriptors used” (additions/updates)
docs/design/datacontracts/EcmaMetadata.md	Updates docs to include TableRW type-size usage
docs/design/datacontracts/data-descriptor-meanings.json	Adds meaning entry for TableRW.Size

[rcj1]

lgtm, good cleanup of generated dependencies.

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[max-charlamb]

/ba-g osx timeouts