Use custom section

Author: surma

lib/assembly/as-bind.ts

@@ -32,6 +32,3 @@ export const __asbind_I32ArrayArray_ID = idof<Array<Array<i32>>>();
 export const __asbind_I64ArrayArray_ID = idof<Array<Array<i64>>>();
 export const __asbind_StringArrayArray_ID = idof<Array<Array<string>>>();
 export const __asbind_BoolArrayArray_ID = idof<Array<Array<bool>>>();
-
-// As-Bind type data
-export const __asbind_type_data: string = "";

read_type_data.js

@@ -20,19 +20,9 @@ function justSatisfyAllImportsLol() {
 
 async function main() {
   const b = await fs.readFile(process.argv[2]);
-  const { instance } = await WebAssembly.instantiate(
-    b,
-    justSatisfyAllImportsLol()
-  );
-  const ptr = instance.exports.__asbind_type_data.value;
-  const dv = new DataView(instance.exports.memory.buffer);
-  const strLen = dv.getUint32(ptr - 4, true);
-  const strView = new Uint16Array(
-    instance.exports.memory.buffer,
-    ptr,
-    strLen / Uint16Array.BYTES_PER_ELEMENT
-  );
-  const str = new TextDecoder("utf-16le").decode(strView);
+  const module = await WebAssembly.compile(b);
+  const buffer = WebAssembly.Module.customSections(module, "bindings")[0];
+  const str = new TextDecoder("utf8").decode(new Uint8Array(buffer));
   console.log({ str });
   const data = JSON.parse(str);
   console.log(JSON.stringify(data, null, 2));

transform.js

@@ -65,14 +65,12 @@ class AsBindTransform extends Transform {
         ])
       )
     };
-    const typeDataExport = [...program.elementsByDeclaration.values()].find(
-      v => v.name === MARKER
-    );
-    if (!typeDataExport) {
-      throw Error("Could not find type data export");
-    }
-    typeDataExport.declaration.initializer = new assemblyscript.StringLiteralExpression(
-      JSON.stringify(typeData)
+    this.typeData = JSON.stringify(typeData);
+  }
+  afterCompile(module) {
+    module.addCustomSection(
+      "bindings",
+      new TextEncoder("utf8").encode(this.typeData)
     );
   }
 }