RGBLINT tool to optimize and improve code

[Rangi42]

There are many "peephole" optimizations that can be applied by searching for suboptimal patterns of assembly code. There may also be reasons to lint code besides optimization (and besides consistent formatting, which would be its own tool; see #1796).

This would be like optimize.py, but ideally running faster, and not tied to pret's preferred formatting and macros (generalizable to all of GB dev). On the other hand, it should have a way to easily define custom lint rules, so it can recognize project-specific macros and exceptions. (For instance, in pret jmp should be recognized by all relevant patterns as a jump instruction, and the Hungarian h/w/v/s RAM prefixes are relevant for some patterns.)

[ReiquelApplegate]

Forgetting to ret at the end of a subroutine, for example, sounds like the kind of bug that could be detected by a linter. Though it gets trickier if it's optimized and instead ends with a jump or call to something else, or a fallthrough comment when it's supposed to do that.

[dmitry-shechtman]

#1796 (comment)

[dmitry-shechtman]

Forgetting to ret at the end of a subroutine, for example, sounds like the kind of bug that could be detected by a linter

No ret at the end of a code section should definitely be a rule.

[dmitry-shechtman]

add 0
sub 0
or 0
xor 0
and $FF

[dmitry-shechtman]

ld X, Y immediately followed by ld X, Z