WebAssembly support #45

aykevl · 2018-10-18T13:22:23Z

Work-in-progress (totally unfinished) branch for WebAssembly support.

TODO:

implement "append" builtin
generate .wasm depending on the extension
generate .wast depending on the extension
write to stdout (how?)
get time.Sleep / time.Now to work
implement runtime.alloc
generate glue JS/HTML
make sure Travis can run all tests automatically with a wasm interpreter (perhaps this one)

fixes #44

justinclift · 2018-10-19T13:08:07Z

For the "write to stdout (how?)" item, @Xe has been developing a runtime environment for Wasm, so might be useful for implementation ideas/direction. 😄

Xe · 2018-10-19T14:22:28Z

Oh hey!

I'd love to collaborate on this using https://github.com/Xe/olin as the runtime for server-side tinygo binaries. The host functions its tool cmd/cwa (which is the binary interface to runtime I have developed) exposes are documented here. The usage of its standard output (which was implemented for the HTTP support shown here) would be kinda like this wast:

(module
 ;; import functions from env
 (func $getStdio (import "cwa" "io_get_stdout") (result i32))
 (func $write (import "cwa" "resource_write") (param i32 i32 i32) (result i32))
 (func $close (import "cwa" "resource_close") (param i32))

 ;; memory
 (memory $mem 1)

 ;; constants
 (data (i32.const 230) "Hello, world!\n")

 (func $main (result i32)
       ;; $fd is the file descriptor of the file we're gonna open
       (local $fd i32)

       ;; $fd = $getStdio();
       (set_local $fd
                  (call $getStdio))

       ;; $write($fd, "Hello, World!\n", 14);
       (call $write
             (get_local $fd)
             (i32.const 230)
             (i32.const 14))
       (drop)

       ;; $close($fd);
       (call $close
             (get_local $fd))

       (i32.const 0))
 (export "cwa_main" (func $main)))

This also has time. I am more than willing to work with you for more runtime support, please just name what you want.

aykevl · 2018-10-19T15:13:37Z

Looks like olin could be very useful for testing!
I just pushed a minimal working example of generated WebAssembly that actually runs. It gets two numbers from JavaScript, adds them in WebAssembly and returns the result to JavaScript.

The only missing thing I see so far is support for sleeping for a given duration, e.g. sleep(int64 nanoseconds). Also, the time precision isn't big enough, but I already commented on that upstream.

justinclift · 2018-10-19T15:22:50Z

Out of curiosity, what's the file size of that minimal working example of WebAssembly?

With mainline Go... minimum file size of generated Wasm (so far) is ~2MB. 😉

aykevl · 2018-10-19T15:25:39Z

Very small.

$ tinygo build -o wasm.wasm examples/wasm

$ ls -l wasm.wasm
-rwxrwxr-x 1 ayke ayke 927 okt 19 17:22 wasm.wasm*

$ tinygo build -o wasm.wasm -no-debug examples/wasm

$ ls -l wasm.wasm
-rwxrwxr-x 1 ayke ayke 221 okt 19 17:22 wasm.wasm*

(Not sure why debug info affects file size, I should investigate that one).

justinclift · 2018-10-19T15:26:44Z

Holy crap. Whooo!!!!!

Again, you rock! 😄

johanbrandhorst · 2018-10-19T15:33:02Z

@aykevl This is a super exciting development. Would you be interested in joining the Go WASM discussion on the Gophers Slack #webassembly channel? https://invite.slack.golangbridge.org/.

aykevl · 2018-10-19T18:14:55Z

Thanks for letting me know! I've joined #webassembly.

Also, just fixed a tiny missed optimization in 3babdfd reducing .wasm size to 174 bytes (160 when compressed). But please note that this small file size is only because the entire runtime gets optimized away by LLVM as it isn't used - an equivalent C program compiled with Clang will probably end up with about the same filesize. A program that actually does something useful and needs some runtime support will probably end up in the range of a few kilobytes. A hello world perhaps half a kilobyte. The scheduler costs something like 2kB on ARM.

deadprogram · 2018-10-19T18:24:34Z

Yeah, this is pretty incredibly awesome.

justinclift · 2018-10-20T02:33:30Z

@aykevl With the wasm.html example, it might be better to remove the <!DOCTYPE html> as it seems to sometimes screw up Firefox with Wasm. No idea why yet though.

aykevl · 2018-10-20T10:37:22Z

That's a standard DOCTYPE. If it screws up WebAssembly in Firefox, that's a bug in Firefox.

Can you give some more details on what exactly goes wrong and when?

aykevl · 2018-10-20T12:00:36Z

Almost finished, I only need to get the tests to pass.

There appears to be an issue with Travis that I haven't investigated closely yet.
Locally, all tests pass except for the ones that print floats (output is garbled).

justinclift · 2018-10-20T15:38:15Z

That's a standard DOCTYPE. If it screws up WebAssembly in Firefox, that's a bug in Firefox.

Can you give some more details on what exactly goes wrong and when?

Yeah, fully agree. I came across it when adding the files here:

Added initial pieces so GitHub Pages can serve this directly bobcob7/wasm-basic-triangle#1

That basic WebGL triangle (and it's counterpart rotating cube) seem like good intro examples for WebGL + Wasm. So I took a bit of time to get the needed bits in place to have GitHub pages serve them directly.

With my Firefox (60.2.x esr version) running on CentOS 7... the Wasm would 100% never be displayed when that doctype line was in the file, but would work fine with it removed. Was 100% repeatable every time (served locally via Caddy when developing), so I just removed it and made a mental note of the problem. Haven't investigated it any further, and wouldn't really know where to start. (nor all that interested really, I'm focused on other stuff 😉)

justinclift · 2018-10-20T15:44:39Z

Oh as a data point, I'm pretty sure no error message was displayed on the javascript console either when it didn't work. That's the usual place to watch out for Wasm errors when executing in a browser.

aykevl · 2018-10-20T17:07:30Z

Maybe leaving out the DOCTYPE triggers quirks mode which fixes a problem with the HTML or CSS?

I strongly prefer avoiding anything non-standard unless I know exactly why that is necessary - and currently I don't.
EDIT: and it works fine for me in Firefox?

justinclift · 2018-10-21T04:36:29Z

EDIT: and it works fine for me in Firefox?

Yeah, not sure. I just noticed it at the time, and it was completely reproducible. So I made the alteration and moved on. If it crops up again, we can look into it then. 😉

iwasaki-kenta · 2018-11-29T03:44:48Z

Is there any way to set func import names?

Example

//go:import _some_func
func someFunc()

aykevl · 2018-11-29T14:36:16Z

Yes:

//go:linkname someFunc _some_func
func someFunc()

iwasaki-kenta · 2018-12-03T12:11:11Z

Yes:

//go:linkname someFunc _some_func
func someFunc()

It seems that the import would be prefixed by the package name (ex: main._some_func). Is there any way to get rid of that prefix?

Additionally, what about changing the import namespace?

aykevl changed the title ~~wasm: WIP~~ WebAssembly support Oct 18, 2018

aykevl force-pushed the wasm branch 2 times, most recently from 2415138 to 5d87aed Compare October 19, 2018 12:42

aykevl mentioned this pull request Oct 19, 2018

TinyGo and WebAssembly? #44

Closed

aykevl force-pushed the wasm branch from fe06649 to f66f889 Compare October 19, 2018 14:46

aykevl force-pushed the wasm branch from 744072c to d24f685 Compare October 20, 2018 11:18

all: add WebAssembly backend

e5e0974

aykevl force-pushed the wasm branch from 9e05bdd to e5e0974 Compare October 21, 2018 17:51

aykevl merged commit e5e0974 into master Oct 21, 2018

deadprogram deleted the wasm branch January 13, 2019 14:00

ZauberNerd pushed a commit to ZauberNerd/tinygo that referenced this pull request Mar 4, 2022

exclude SC2050 shellcheck rule (fix tinygo-org#45)

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WebAssembly support #45

WebAssembly support #45

aykevl commented Oct 18, 2018 •

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iwasaki-kenta commented Dec 3, 2018

WebAssembly support #45

WebAssembly support #45

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