Introduce a new internal EventSourceGenerator and use it for all ES implementations

[EgorBo]

Closes #28290

1. Remove [EventSourceAutoGenerate], we rely on just [EventSource] + no explicit ctors
2. Introduce a new global SourceGenerators - EventSourceGenerator (and move the existing impl from SPC.Generators to this new project)
3. Update slnx files (via the UpdateSolutionFiles task)
4. Migrate all classes with [EventSource] to use the SG. Except for the ones with EventSourceSettings.EtwSelfDescribingEventFormat -- there are 3 ES impl defining this settings 🤔

[EgorBo]

hm.. probably should move the SLNX update to a separate (last) commit (or maybe even PR?)

[stephentoub]

we rely on just [EventSource] + no explicit ctors

We will likely want more than just this, e.g. it'll need to be partial.

[stephentoub]

Update slnx files

Do we need to modify the slnx files? Could we instead globally include via .props?

[EgorBo]

Update slnx files

Do we need to modify the slnx files? Could we instead globally include via .props?

it's not needed to build the projects, but needed for people opening slnx files for the SG project to show up there in slnx. All other source generator projects are already added there (added automatically by the UpdateSolutionFile task, which is manually invoked (it's slow))

[Copilot]

Pull Request Overview

This PR introduces a source generator for EventSource classes to automatically generate constructors and metadata, eliminating the need for manual boilerplate code. The generator creates parameterless constructors that call the base EventSource constructor with the correct parameter order (name, guid).

Key changes:

• Introduces EventSourceGenerator source generator that triggers on classes with [EventSource] attribute
• Removes [EventSourceAutoGenerate] attribute and makes affected EventSource classes partial
• Changes EventSource base constructor parameter order from (Guid, string) to (string, Guid) for consistency
• Removes manual constructors from EventSource classes across the codebase

Reviewed Changes

Copilot reviewed 50 out of 50 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
EventSourceGenerator.cs	New source generator that creates constructors for EventSource classes
EventSourceGenerator.Parser.cs	Parser logic to extract EventSource metadata and validate constructors
EventSourceGenerator.Emitter.cs	Code generation logic for constructors and provider metadata
EventSource.cs	Changes constructor parameter order and visibility for source generator
TraceLoggingEventSource.cs	Updates constructor call to match new parameter order
Multiple EventSource classes	Removes manual constructors and adds partial keyword
NetCoreAppLibrary.props	Registers EventSourceGenerator
generators.targets	Enables generator for source projects
Directory.Build.props	Suppresses ESGEN001 warnings globally

Comments suppressed due to low confidence (1)

src/libraries/System.Private.CoreLib/gen/EventSourceGenerator.Parser.cs:24

• The parser only checks for NamespaceDeclarationSyntax but doesn't check for FileScopedNamespaceDeclarationSyntax. This will cause the generator to skip classes in file-scoped namespaces. Use BaseNamespaceDeclarationSyntax as the base type to handle both traditional and file-scoped namespace declarations.

[jkotas]

Unused?

[EgorBo]

@copilot address the recent feedback

[EgorBo]

oh, that doesn't work that way?

[jkotas]

oh, that doesn't work that way?

You can ask it to create a PR against your branch, but it will never do a direct push into your branch currently.

[jkotas]

Thank you!