churf/src/GC/todo.md

Garbage collection

Project

Goal for next week (24/2):

• Debug

GC TODO:

• Merge to main branch
• Fix singleton references
• Get a good grasp of how the adressing of stack frames actually works.
• Debug "free()", sometimes it skips chunks that should be freed.
• Check alignment of chunks.
• Think about how we want to determine if some object is a pointer or not, probably will have to discuss that with Samuel. Since it is not ideal to determine in the GC if an object is a pointer or not. It should preferably be done in a previous stage.

Tests TODO

Library linking

Victor fixes this Compile the GC lib and a test separately, link them together and evalutate the following:

__builtin_frame_address(0)
__builtin_frame_address(1)
__builtin_return_address(0)
__builtin_return_address(1)

GC Init and __b_f_a

1. Save the first stack fram globally as the stack start

2. For each call to collect, save the prev stack frame as the stack end

3. Scan through the span

   gc_init() global stack_end = __builtin_frame_address(1)

   collect() local stack_start = __builtin_frame_address(1)

   sweep() for all addr in range(stack_end, stack_start) mark if chunk