Graph IR

[MDFL64]

Began work on an IR today. It is locked behind a compiler flag (--useGraphIR) to facilitate easy testing + continued development alongside the main branch. It currently does not work at all.

• [x] Convert WASM control flow to graph IR.
• [x] Add all instructions to IR (No good dataflow yet, just for testing control flow).
• [ ] Test basic control flow. (Just link blocks together with gotos for now)
• [ ] Local dataflow: Each control block tracks which locals it uses, and the values locals are bound to when they terminate.
• [ ] Better control flow code generation.
• [ ] Proper bounding of variable lifetimes.
• [ ] Handling for very large jumps.
• [ ] Proper handling of setjmp/longjmp (setjmp should split control blocks).

Other thoughts:

• Planning to deal with block results by creating an extra pseudo-local and throwing it in block outputs.
• Track nesting to avoid the parser throwing a fit. Might be able to decompose expressions that are too large by creating a small scope with temp vars.
• Track estimate of LJ opcodes to avoid large jumps.
• Might be able to convert some loops into lua for loops.
• Maybe convert some blocks to functions? I'm not sure how the JIT feels about lambdas, will need to test.

[MDFL64]

Progress is being made on adding instructions to IR. Yet to do:

• ~~Indirect calls.~~
• ~~All memory reads/writes.~~
• ~~Global reads.~~
• ~~All conversions.~~
• ~~Select.~~
• ~~grow_memory / current_memory~~
• ~~"bitwise" float ops (neg, abs, copysign)~~
• ~~(Temp) local init~~

Some minor TODOS:

• Write barriers are broken trash.
• I started on a function for stripping parens from statements that don't need them (function args and the like) but never finished it.

[MDFL64]

Todo: Bools should be preserved for select opcode.