Trapped on unreachable instruction in a go-pdk example

[sap1ens]

This could be more relevant for https://github.com/dylibso/chicory, but creating an issue here to start.

I want to run a JSON example from the go-pdk. I can compile the example with tinygo and run it with the extism CLI:

extism call plugin.wasm add --input='{"a": 20, "b": 21}' --wasi
{"sum":41}

However, I'm getting com.dylibso.chicory.runtime.TrapException: Trapped on unreachable instruction when trying to run it with chicory-sdk. Debugging the interpreter steps shows me that it goes to panic directly from the exported function, but it's not clear why.

Here's the minimal test to reproduce:

package org.extism.sdk.chicory;

import com.dylibso.chicory.wasi.WasiOptions;
import junit.framework.TestCase;

import java.io.IOException;
import java.nio.charset.StandardCharsets;

public class GolangTest extends TestCase {
    public void testJson() throws IOException {
        var wasm = ManifestWasm.fromBytes(this.getClass().getResourceAsStream("/add.wasm").readAllBytes()).build();
        var manifest = Manifest.ofWasms(wasm).withOptions(new Manifest.Options().withWasi(WasiOptions.builder().build())).build();

        var plugin = Plugin.ofManifest(manifest).build();

        var input = "{\"a\": 20, \"b\": 21}";
        var result = new String(plugin.call("add", input.getBytes(StandardCharsets.UTF_8)), StandardCharsets.UTF_8);

        System.out.println(result);
    }
}

add.wasm was compiled from the go-pdk JSON example like this:

tinygo build -o add.wasm -target wasip1 -buildmode=c-shared main.go

[sap1ens]

Here's the compiled wasm file: add.wasm.zip

[sap1ens]

In fact, even the simplest greet function without any JSON usage throws the same exception.

[sap1ens]

I was able to get the panic message:

//go:wasmexport function called before runtime initialization

So I guess it's related to the way the module is initialized?

[sap1ens]

Confirming that adding a call to _initialize before any other calls solves the issue!

Not sure where it should be called though.

[evacchi]

sorry I did not reply to this earlier. Has this been solved in the meantime?

[sap1ens]

I believe I had to switch to GOOS=wasip1 GOARCH=wasm go build instead of using TinyGo. _initialize is used by go build, but not TinyGo (at least at the time of my investigation).

[evacchi]

I think the trick for tinygo is to use -buildmode=c-shared, that was a recent change though, see https://github.com/extism/go-pdk#:~:text=Compile%20this%20with%20the%20command%3A

I am not 100% sure we invoke _initialize at all though, I should check that!