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Garbage Collection (WasmGC)

WasmGC provides reference-typed objects (structs, arrays) that engines can manage with garbage collection. This enables efficient runtimes for languages like Kotlin, Java, and Dart.

Key concepts:

  • Reference-typed heaps managed by the VM.
  • Typed struct and array values.
  • Interop with host via externref.

Syntax and support are still evolving — check your toolchain’s documentation for exact WAT forms.

Instruction Reference

Section titled “Instruction Reference”
  • GC Types — sub, final, rec, field, struct, array
  • GC Struct — struct.new, struct.get, struct.set
  • GC Array — array.new, array.get, array.set, array.len
  • GC i31 — ref.i31, i31.get_s, i31.get_u
  • GC Casts — ref.test, ref.cast, br_on_cast