gc.md

Maru's GC

The current GC is a simple, singly-linked list of chunks that get marked and sweeped. When more memory is needed, the a new chunk is malloced and chained at the end.

A chunk can be opaque, meaning that the payload doesn't contain any further pointers to other obejcts. Conversely, a non-opaque chunk's payload may only contain OOPs.

TODO

I want to emit full heap objects (e.g. the literal strings in code), into a static, read-only memory segment. In that setup the compiled code only needs to deal with one kind of string representation (no more C strings, only full <string> objects, it's just that some of them are in the/a static memory segment).

Split <header> into <chunk-header> and <object-header>. The chunk's type should be used to mark whether the chunk's payload contains raw data, or a full object with an .

(define-record <chunk-header> ()
  (next size [payload type and flags packed into one word]))

(define-record <object-header> ()
  (descriptor (when-at-expand feature/object-canary canary)))

(define-record <object-descriptor> ()
  (type-id
  [description for the GC about which word contains an OOP to be walked]
  ))

Or maybe instead of the <object-descriptor> its should just point to the <type> object itself?

Chunk type examples:

• a simple-array of bytes (of chunk-size elements)
• object (i.e. the chunk payload begins with an <object-header>)
• a boxed float
• a boxed word
• etc.