Enable TeaVM WASM GC Backend

I'd tried this ages ago, and had some issues I utterly failed to find a
minimal reproducer for. Now it Just Works.

package-lock.json

@@ -12,7 +12,8 @@
         "@squid-dev/cc-web-term": "^2.0.0",
         "preact": "^10.5.5",
         "setimmediate": "^1.0.5",
-        "tslib": "^2.0.3"
+        "tslib": "^2.0.3",
+        "wasm-feature-detect": "^1.8.0"
       },
       "devDependencies": {
         "@rollup/plugin-node-resolve": "^16.0.0",
@@ -3262,6 +3263,12 @@
         "url": "https://opencollective.com/unified"
       }
     },
+    "node_modules/wasm-feature-detect": {
+      "version": "1.8.0",
+      "resolved": "https://registry.npmjs.org/wasm-feature-detect/-/wasm-feature-detect-1.8.0.tgz",
+      "integrity": "sha512-zksaLKM2fVlnB5jQQDqKXXwYHLQUVH9es+5TOOHwGOVJOCeRBCiPjwSg+3tN2AdTCzjgli4jijCH290kXb/zWQ==",
+      "license": "Apache-2.0"
+    },
     "node_modules/web-namespaces": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/web-namespaces/-/web-namespaces-2.0.1.tgz",

package.json

@@ -9,7 +9,8 @@
     "@squid-dev/cc-web-term": "^2.0.0",
     "preact": "^10.5.5",
     "setimmediate": "^1.0.5",
-    "tslib": "^2.0.3"
+    "tslib": "^2.0.3",
+    "wasm-feature-detect": "^1.8.0"
   },
   "devDependencies": {
     "@rollup/plugin-node-resolve": "^16.0.0",

projects/web/rollup.config.js

@@ -88,9 +88,9 @@ const ccTweaked = minify => {
             }
         },
 
+        /** @type {import("rollup").ResolveIdHook} */
         async resolveId(source) {
-            if (source === "cct/classes") return path.resolve("build/teaVM/classes.js");
-            if (source === "cct/resources") return path.resolve("build/teaVM/resources.js");
+            if (source.startsWith("cct/")) return path.resolve("build/teaVM/" + source.substring(4));
             return null;
         },
 
@@ -124,7 +124,7 @@ export default args => ({
         resolve({ browser: true }),
 
         url({
-            include: ["**/*.dfpwm", "**/*.worker.js", "**/*.png"],
+            include: ["**/*.dfpwm", "**/*.worker.js", "**/*.png", "**/*.wasm"],
             fileName: "[name]-[hash][extname]",
             publicPath: "/",
             limit: 0,

projects/web/src/builder/java/cc/tweaked/web/builder/Builder.java

@@ -19,6 +19,7 @@ import java.nio.charset.StandardCharsets;
 import java.nio.file.FileSystems;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
@@ -70,14 +71,24 @@ public class Builder {
         }
 
         // Then finally start the compiler!
+        run(output, remapper, TeaVMTargetType.JAVASCRIPT, TeaVMOptimizationLevel.ADVANCED, minify);
+        run(output, remapper, TeaVMTargetType.WEBASSEMBLY_GC, TeaVMOptimizationLevel.SIMPLE, minify);
+
+        try (var runtime = Builder.class.getClassLoader().getResourceAsStream("org/teavm/backend/wasm/wasm-gc-module-runtime.js")) {
+            if (runtime == null) throw new IllegalStateException("Cannot find WASM runtime");
+            Files.copy(runtime, output.resolve("wasm-gc-runtime.js"), StandardCopyOption.REPLACE_EXISTING);
+        }
+    }
+
+    private static void run(Path output, ClassLoader classes, TeaVMTargetType target, TeaVMOptimizationLevel optimise, boolean minify) throws Exception {
         var tool = new TeaVMTool();
-        tool.setTargetType(TeaVMTargetType.JAVASCRIPT);
+        tool.setTargetType(target);
         tool.setJsModuleType(JSModuleType.ES2015);
         tool.setTargetDirectory(output.toFile());
-        tool.setClassLoader(remapper);
+        tool.setClassLoader(classes);
         tool.setMainClass("cc.tweaked.web.Main");
 
-        tool.setOptimizationLevel(TeaVMOptimizationLevel.ADVANCED);
+        tool.setOptimizationLevel(optimise);
         tool.setObfuscated(minify);
 
         tool.generate();

projects/web/src/frontend/emu/java.ts

@@ -4,11 +4,31 @@
 
 import "setimmediate";
 
-import type { ComputerDisplay, ComputerHandle } from "cct/classes";
-export type { ComputerDisplay, ComputerHandle, PeripheralKind, Side } from "cct/classes";
+import type { ComputerDisplay, ComputerHandle } from "cct/classes.js";
+export type { ComputerDisplay, ComputerHandle, PeripheralKind, Side } from "cct/classes.js";
+import { load as teaVMLoad } from "cct/wasm-gc-runtime.js";
+import { exceptions, gc } from "wasm-feature-detect";
+import wasmClasses from "cct/classes.wasm";
+
+const loadClasses = async (): Promise<{ main: (args: string[]) => void }> => {
+    if (
+        typeof WebAssembly === "object" && typeof WebAssembly.compileStreaming === "function" &&
+        await exceptions() && await gc()
+    ) {
+        try {
+            console.log("Loading WASM runtime");
+            return (await teaVMLoad(wasmClasses)).exports;
+        } catch (e) {
+            console.error("Failed to load WebAssembly runtime", e);
+        }
+    }
+
+    console.log("Using JS runtime");
+    return await import("cct/classes.js");
+}
 
 const load = async (): Promise<(computer: ComputerDisplay) => ComputerHandle> => {
-    const [classes, { version, resources }] = await Promise.all([import("cct/classes"), import("cct/resources")]);
+    const [classes, { version, resources }] = await Promise.all([loadClasses(), import("cct/resources.js")]);
 
     let addComputer: ((computer: ComputerDisplay) => ComputerHandle) | null = null;
     const encoder = new TextEncoder();
@@ -18,7 +38,7 @@ const load = async (): Promise<(computer: ComputerDisplay) => ComputerHandle> =>
         listResources: () => Object.keys(resources),
         getResource: path => new Int8Array(encoder.encode(resources[path]))
     };
-    classes.main();
+    classes.main([]);
 
     if (!addComputer) throw new Error("Callbacks.setup was never called");
     return addComputer;

projects/web/src/frontend/typings.d.ts

@@ -28,16 +28,21 @@ declare module "*.license" {
 }
 
 declare module "*.dfpwm" {
-    const contents: string;
-    export default contents;
+    const url: string;
+    export default url;
 }
 
-declare module "cct/resources" {
+declare module "*.wasm" {
+    const url: string;
+    export default url;
+}
+
+declare module "cct/resources.js" {
     export const version: string;
     export const resources: Record<string, string>;
 }
 
-declare module "cct/classes" {
+declare module "cct/classes.js" {
     export const main: () => void;
 
     export type Side = "up" | "down" | "left" | "right" | "front" | "back";
@@ -169,10 +174,18 @@ declare module "cct/classes" {
     }
 }
 
+declare module "cct/wasm-gc-runtime.js" {
+    export const load: (url: string, options?: any) => Promise<{
+        exports: { main: (args: string[]) => void },
+        instance: WebAssembly.Instance,
+        module: WebAssembly.Module,
+    }>
+}
+
 declare namespace JSX {
     export type Element = import("preact").JSX.Element;
     export type IntrinsicElements = import("preact").JSX.IntrinsicElements;
     export type ElementClass = import("preact").JSX.ElementClass;
 }
 
-declare var $javaCallbacks: import("cct/classes").Callbacks; // eslint-disable-line no-var
+declare var $javaCallbacks: import("cct/classes.js").Callbacks; // eslint-disable-line no-var

projects/web/src/main/java/cc/tweaked/web/js/Callbacks.java

@@ -54,7 +54,7 @@ public class Callbacks {
      * @param resource The path to the resource to load.
      * @return The loaded resource.
      */
-    @JSByRef
+    @JSByRef(optional = true)
     @JSBody(params = "name", script = "return $javaCallbacks.getResource(name);")
     public static native byte[] getResource(String resource);