Google Summer of Code 2013/cs648/Initial Meeting
cps is analogous to coroutine_fn
cps is infact a GCC function attribute - __attribute__((cps))
A good first task is to check the annotations in the QEMU tree are correct as they are currently untested
Need to understand distinctions between packed/unpacked mode (also ecpc)
Suggest will take a week to read and understand the workings of cpc_runtime:
- needs a blogpost to explain it as documentation once understood
- any bugs/optimisations noticed should be submitted as (separate patches)
A good place to start is to examine the different stages of CPC translation (accessed with -stageX option)
Best test compilation is cpc/samples/loops.cpc
May turn out that coroutine_io.c is entirely built on coroutine.h primitives and therefore will not need editing for CPC variant.
Need to read and reimplement:
- cpc_sleep
- cpc_spawn (not annotated with cps)
- cpc_yield
- cpc_invoke/call
Don't need cpc_main loop
Extensions
Good extension is to skip translation if no cps functions, compile as C
Need to benchmark result extensively, is important for understanding different "calling conventions" -ecpc mode and packed vs unpacked
Milestone
Aim by Friday 21st is to produce a blog post documenting CPC memory format and how functions manipulate it
"anatomy of a continuation"
- Define a CPC continuation as a datastructure
- how it works in practise
- detail cpc_push/cpc_invoke (also cpc-yield, cpc_spawn, cpc_patch)