GBC: Gengo Bytecode Cache — implementation

[ganehag]

The GBC spec is complete (docs/gbc-spec.md). Implementation has not started. GBC is a compiled module artifact that lets the runtime skip parsing and code generation for a known source file. It is not a heap snapshot.

Suggested first milestone

A minimal round-trip: writer + reader for a simple script with:

• No imports
• One bytecode section
• Constants
• Functions
• Empty types table
• Empty dependency table

Then add validation failures one by one until the full spec is covered.

Why it matters

• Eliminates parse + compile overhead on repeated loads of the same module
• Enables ahead-of-time compilation workflows (compile on dev machine, ship .gbc to constrained host)
• Required foundation for any future caching or separate compilation story

Notes

• GBC is not a memory snapshot — the VM still allocates and initialises objects at load time
• The spec covers magic bytes, version field, section table, and a dependency hash for invalidation
• See docs/gbc-spec.md for the full format