fix engine imports in treeshaking list

Signed-off-by: karthik2804 <[email protected]>

crates/spidermonkey-embedding-splicer/src/lib.rs

@@ -148,9 +148,25 @@ impl Guest for SpidermonkeyEmbeddingSplicerComponent {
             },
         )) = decode(&engine)
         {
-            // merge the imports from the engine with the imports from the guest content.
-            for (k, _) in &engine_resolve.worlds[engine_world].imports {
-                guest_imports.push(engine_resolve.name_world_key(k));
+            {
+                // Componentize the Starlingmonkey engine so that we can pull in the imports that are actually used.
+                let bytes = include_bytes!("../../../StarlingMonkey/host-apis/wasi-0.2.0/preview1-adapter-release/wasi_snapshot_preview1.wasm");
+                let component = wit_component::ComponentEncoder::default()
+                    .adapter("wasi_snapshot_preview1", bytes)
+                    .map_err(|e| e.to_string())?
+                    .module(&engine)
+                    .map_err(|e| e.to_string())?
+                    .encode()
+                    .map_err(|e| e.to_string())?;
+                let decoded = wit_component::decode(&component).unwrap();
+                let resolve = decoded.resolve();
+                let packages = decoded.package();
+                let world_id = resolve.select_world(packages, None).unwrap();
+                let world = &resolve.worlds[world_id];
+                // merge the imports actually used by the engine with the imports from the guest content.
+                for (import_key, _) in world.imports.iter() {
+                    guest_imports.push(resolve.name_world_key(import_key));
+                }
             }
 
             // we disable the engine run and incoming handler as we recreate these exports