Avoid allocating per-cursor LazyList factory delegates using function pointers#715
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… pointers `LazyList<T>` previously stored a `Func<int, T>` (or `Func<int, T?, T>`) factory per instance, which allocated a closure delegate for every cursor that exposed a lazy child list -- even when the list was empty (the common case for `Decl._attrs`). Mirroring the `ValueLazy<TSelf, T>` conversion, the factory is now a `delegate*<object, int, T>` function pointer plus a stored `object _self`, so the closure allocation is gone. All owners (`Cursor`, `Type`, `TemplateArgument`) are reference types, so passing `this` as `object self` never boxes. Each former lambda becomes a `static` factory method that casts `self` back to the owning type. Measured on the TerraFX d3d12 generation workload (gc-verbose, `DOTNET_TieredCompilation=0`): `Func<int, Decl, Decl>` (~2.0 MB) and `Func<int, Attr>` (~1.9 MB) are eliminated entirely, dropping sampled allocations from ~142.6 MB to ~134.2 MB. No behavioral change; all 3708 golden tests pass. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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LazyList<T>stored aFunc<int, T>(orFunc<int, T?, T>) factory per instance, which allocated a closure delegate for every cursor that exposed a lazy child list -- even when the list was empty (the common case forDecl._attrs). Mirroring theValueLazy<TSelf, T>conversion in #707, the factory is now adelegate*<object, int, T>function pointer plus a storedobject _self, so the per-instance closure allocation is gone.All owners (
Cursor,Type,TemplateArgument) are reference types, so passingthisasobject selfnever boxes. Each former lambda becomes astaticfactory method that castsselfback to the owning type. The four nested_templateParameterListssites are deduplicated into a sharedDecl.CreateTemplateParameterListshelper.Measured on the TerraFX
d3d12generation workload (gc-verbose,DOTNET_TieredCompilation=0):Func<int, Decl, Decl>(~2.0 MB) andFunc<int, Attr>(~1.9 MB) are eliminated entirely, dropping sampled allocations from ~142.6 MB to ~134.2 MB. No behavioral change; all 3708 golden tests pass, output is byte-identical.Note
This PR description was drafted by Copilot.