1000+ LoC spent; just 300+ excluding tests.
Still one known gap; we don't check the entirety of an array's element
type if it's a compound. So far we just check if say both sides start with
'addr'. Obviously that's not good enough.
I thought I'd done this in the previous commit, but I hadn't. And, what's
more, there was a bug that seemed pretty tough for a time. Turns out my
self-hosted translator doesn't support '.' comment tokens in data segments.
Hopefully I'm past the valley of the shadow of death now.
"I HAVE NO TOOLS BECAUSE I’VE DESTROYED MY TOOLS WITH MY TOOLS."
-- James Mickens (https://www.usenix.org/system/files/1311_05-08_mickens.pdf)
If indexing into a type with power-of-2-sized elements we can access them
in one instruction:
x/reg1: (addr int) <- index A/reg2: (addr array int), idx/reg3: int
This translates to a single instruction because x86 instructions support
an addressing mode with left-shifts.
For non-powers-of-2, however, we need a multiply. To keep things type-safe,
it is performed like this:
x/reg1: (offset T) <- compute-offset A: (addr array T), idx: int
y/reg2: (addr T) <- index A, x
An offset is just an int that is guaranteed to be a multiple of size-of(T).
Offsets can only be used in index instructions, and the types will eventually
be required to line up.
In the process, I have to expand Input-size because mu.subx is growing
big.
A couple more primitives now working. In the process I ran into an issue
with some buffer filling up when running ntranslate. Isolating it to survey.subx
was straightforward, but --trace ran out of RAM, and --trace --dump ran
out of (7GB of) disk. In the end what helped was just repeatedly inserting
exits at different points, and I realized there was a magic number that
hadn't been turned into a named constant.
This undoes 5672 in favor of a new plan:
Layers 000 - 099 are for running without syntax sugar. We use them for
building syntax-sugar passes.
Layers 100 and up are for running with all syntax sugar.
The layers are arranged in approximate order so more phases rely on earlier
layers than later ones.
I plan to not use intermediate syntax sugar (just sigils without calls,
or sigils and calls without braces) anywhere except in the specific passes
implementing them.
