internal: some WIP on being able to compile wazero for MCUs using TinyGo

[deadprogram]

This PR is a place for some WIP on getting wazero to compile with TinyGo so it can be run on microcontrollers.

See #1854 for details.

This is as far as I have been able to get this far with the code in this PR:

$ tinygo build -o basic.uf2 -target=itsybitsy-m4 -tags=tinygo ./examples/basic/
# github.com/tetratelabs/wazero/internal/sock
internal/sock/sock.go:66:59: undefined: net.TCPListener
internal/sock/sock_supported.go:8:22: undefined: syscall.SHUT_RD
internal/sock/sock_supported.go:9:22: undefined: syscall.SHUT_RDWR
internal/sock/sock_supported.go:10:22: undefined: syscall.SHUT_WR
internal/sock/sock.go:73:28: undefined: net.TCPListener

[deadprogram]

Now that I look bit deeper, the bigger problem is likely to be not being able to generate the needed code for the target itself that it would be running on: https://github.com/tetratelabs/wazero/tree/main/internal/asm

This is not a small task.

[ncruces]

Is an interpreter not useful at all?

[deadprogram]

Is an interpreter not useful at all?

I would be happy to get interpreter working, but not sure that will work either due to instruction set of target being ARMv7-M Thumb

[evacchi]

the interpreter should work regardless. You can compile wazero today to wasm with GOOS=wasip1 GOARCH=wasm and it will build the interpreter.

[deadprogram]

the interpreter should work regardless.

OK, good to know. I will continue playing with it this weekend.

[deadprogram]

With my latest commits using a couple unmerged branches of tinygo, I am now getting this:

$ tinygo build -o wazero-micro.uf2 -target itsybitsy-m4 -stack-size 8kb -tags tinygo ./examples/basic/
tinygo:ld.lld: error: undefined hidden symbol: __math_invalidf
>>> referenced by sf_sqrt.c:0 (/home/ron/Development/tinygo/tinygo/lib/picolibc/newlib/libm/math/sf_sqrt.c:0)
>>>               sf_sqrt.c.o:(sqrtf) in archive /home/ron/.cache/tinygo/picolibc-thumbv7em-unknown-unknown-eabi-cortex-m4/lib.a
>>> did you mean: __math_invalid
>>> defined in: /home/ron/.cache/tinygo/picolibc-thumbv7em-unknown-unknown-eabi-cortex-m4/lib.a(math_err_invalid)
failed to run tool: ld.lld
error: failed to link /tmp/tinygo2978757582/main: exit status 1

[deadprogram]

A couple fixes from @aykevl and I was able to at least compile:

$ tinygo build -size short -o wazero-micro.uf2 -target itsybitsy-m4 -stack-size 8kb -tags tinygo ./examples/basic/
   code    data     bss |   flash     ram
 375788   72072   18544 |  447860   90616

Now to start getting things to work!

[evacchi]

Nice!

[evacchi]

nice to see further progress here!

[evacchi]

should we close this one?

[deadprogram]

Closing in favor of the @orsinium collection of PRs.