Vladimir Zotov (Dec 09 2023 at 21:24): Vladimir Zotov (Dec 09 2023 at 21:24):I'm trying to compile nodejs-wasm example in a docker image with roc nightly and zig 0.11. Getting an error for this file
https://github.com/roc-lang/roc/blob/main/examples/nodejs-interop/wasm/platform/host.zig
$ roc build --target=wasm32
🔨 Rebuilding platform...
An internal compiler expectation was broken.
This is definitely a compiler bug.
Please file an issue here: https://github.com/roc-lang/roc/issues/new/choose
thread '<unnamed>' panicked at 'Error:
Failed to rebuild host.zig:
The executed command was:
zig build-obj platform/host.zig -femit-llvm-ir=platform/main.bc --mod glue::/roc/crates/compiler/builtins/bitcode/src/glue.zig --deps glue --library c -target wasm32-wasi -fPIC -fstrip
stderr of that command:
platform/host.zig:27:33: error: expected type 'u32', found 'type'
platform/host.zig:33:23: error: expected type 'u32', found 'type'
', crates/compiler/build/src/link.rs:1414:21
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Is there an easy fix (in the Zig file I suppose)?
Brendan Hansknecht (Dec 09 2023 at 21:34):we probably missed updating it to 0.11
Brendan Hansknecht (Dec 09 2023 at 21:36):Oh, I see
Brendan Hansknecht (Dec 09 2023 at 21:36):In some place we use @alignOf(Align) and others just Align
Brendan Hansknecht (Dec 09 2023 at 21:36):yeah, small fix
Vladimir Zotov (Dec 10 2023 at 07:46):@Brendan Hansknecht Here you go
https://github.com/roc-lang/roc/pull/6237
Vladimir Zotov (Dec 10 2023 at 08:29):Now it is complaining that it cannot find wasi-libc.a. I guess I could install or build it but I'm not sure that there are more things to install as well. Does anyone know?
Brian Carroll (Dec 10 2023 at 09:02):If you build the compiler from source it should build that file. I think we might not be packaging it correctly.
Vladimir Zotov (Dec 11 2023 at 07:51):It took me a few hours to figure out how to build compiler in my Docker file. The thing I'm trying to understand now is how to get past this error during building:
No suitable version of LLVM was found system-wide or pointed...
Anton (Dec 11 2023 at 10:27):Hi @Vladimir Zotov,
You need to set LLVM_SYS_160_PREFIX to the path of where you installed llvm 16.
Pearce Keesling (Dec 11 2023 at 19:14):I think there's an open GitHub issue for the wasi-libc issues. I remember running into that a while back
Vladimir Zotov (Dec 11 2023 at 20:18):I know, there are two of them actually, I already explored them. Building from scratch was the answer. Annoyingly, apt install for llvm is broken on Ubuntu with a ticket open on github, so I have to do a sad plain download of clang, llvm and other stuff.
Vladimir Zotov (Dec 11 2023 at 20:20):I'm making a VSCode devcontainer, which makes getting started with roc super easy (I got it running the roc's CLI example). I'll probably get there with node WASM as well :melting_face:
Anton (Dec 12 2023 at 10:36):This file may also be useful to you
Vladimir Zotov (Dec 12 2023 at 15:54):Thanks! I've got mine working as well in the end :upside_down:
Vladimir Zotov (Dec 12 2023 at 20:52):Hey @Brendan Hansknecht
https://github.com/roc-lang/roc/blob/012d93574ae59ce67647d7e2dcd9b47c93855651/examples/nodejs-interop/wasm/hello.js#L4
That line assumes the compiled file is called roc-app.wasm but instead mine is compiled tomain.wasm. Should I submit a PR with the change??
If it is, I've got a runtime error:
const instance = new WebAssembly.Instance(wasmModule, importObj);
^
LinkError: WebAssembly.Instance(): Import #2 module="wasi_snapshot_preview1" function="random_get" error: function import requires a callable
at hello (/home/node/proj/hello.js:44:22)
I have no idea where it gets random_get from :melting_face:
Brian Carroll (Dec 13 2023 at 07:11):That's a WASI function it's trying to import into the Wasm module so something in the platform must be using it.
Last updated: Jul 26 2025 at 12:14 UTC