Emit component name in core Wasm file names (#408)

Author: Guy Bedford

crates/bindgen-core/src/component.rs

@@ -62,9 +62,7 @@ pub fn generate(
     // Insert all core wasm modules into the generated `Files` which will
     // end up getting used in the `generate_instantiate` method.
     for (i, module) in modules.iter() {
-        let i = i.as_u32();
-        let name = format!("module{i}.wasm");
-        files.push(&name, module.wasm);
+        files.push(&gen.core_file_name(name, i), module.wasm);
     }
 
     // With all that prep work delegate to `WorldGenerator::generate` here
@@ -100,5 +98,14 @@ pub trait ComponentGenerator: WorldGenerator {
         interfaces: &ComponentInterfaces,
     );
 
+    fn core_file_name(&mut self, name: &str, idx: StaticModuleIndex) -> String {
+        let i_str = if idx.as_u32() == 0 {
+            String::from("")
+        } else {
+            (idx.as_u32() + 1).to_string()
+        };
+        format!("{}.core{i_str}.wasm", name)
+    }
+
     fn finish_component(&mut self, name: &str, files: &mut Files);
 }

crates/gen-host-js/src/lib.rs

@@ -220,6 +220,7 @@ impl ComponentGenerator for Js {
         // bindings is the actual `instantiate` method itself, created by this
         // structure.
         let mut instantiator = Instantiator {
+            name,
             src: Source::default(),
             gen: self,
             modules,
@@ -434,7 +435,7 @@ impl Js {
                             _fs = _fs || await import('fs/promises');
                             return WebAssembly.compile(await _fs.readFile(url));
                         }
-                        return fetch(url).then(WebAssembly.compile);
+                        return fetch(url).then(WebAssembly.compileStreaming);
                     }
                 ")
             } else {
@@ -684,6 +685,7 @@ impl Js {
 ///
 /// This is the main structure for parsing the output of Wasmtime.
 struct Instantiator<'a> {
+    name: &'a str,
     src: Source,
     gen: &'a mut Js,
     modules: &'a PrimaryMap<StaticModuleIndex, ModuleTranslation<'a>>,
@@ -707,6 +709,7 @@ impl Instantiator<'_> {
 
         // Setup the compilation promises
         let mut first = true;
+        let mut multiple = false;
         for init in self.component.initializers.iter() {
             if let GlobalInitializer::InstantiateModule(InstantiateModule::Static(idx, _)) = init {
                 // Get the compiled WebAssembly.Module objects in parallel
@@ -715,9 +718,12 @@ impl Instantiator<'_> {
                         self.src.js.push_str("\n");
                     }
                     first = false;
+                } else {
+                    multiple = true;
                 }
+
                 let local_name = format!("module{}", idx.as_u32());
-                let name = format!("module{}.wasm", idx.as_u32());
+                let name = self.gen.core_file_name(&self.name, *idx);
                 if self.gen.opts.instantiation {
                     uwrite!(
                         self.src.js,
@@ -735,7 +741,7 @@ impl Instantiator<'_> {
 
         // To avoid uncaught promise rejection errors, we attach an intermediate
         // Promise.all with a rejection handler, if there are multiple promises.
-        if first == false {
+        if multiple {
             first = true;
             self.src.js.push_str("Promise.all([");
             for init in self.component.initializers.iter() {

crates/gen-host-wasmtime-py/src/lib.rs

@@ -452,6 +452,7 @@ impl ComponentGenerator for WasmtimePy {
         );
         self.init.indent();
         let mut i = Instantiator {
+            name,
             gen: self,
             modules,
             component,
@@ -496,6 +497,7 @@ impl ComponentGenerator for WasmtimePy {
 }
 
 struct Instantiator<'a> {
+    name: &'a str,
     gen: &'a mut WasmtimePy,
     modules: &'a PrimaryMap<StaticModuleIndex, ModuleTranslation<'a>>,
     instances: PrimaryMap<RuntimeInstanceIndex, StaticModuleIndex>,
@@ -578,12 +580,13 @@ impl<'a> Instantiator<'a> {
 
     fn instantiate_static_module(&mut self, idx: StaticModuleIndex, args: &[CoreDef]) {
         let i = self.instances.push(idx);
+        let core_file_name = self.gen.core_file_name(&self.name, idx);
         self.gen.init.pyimport("os", None);
 
         uwriteln!(
             self.gen.init,
-            "path = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'module{}.wasm')",
-            idx.as_u32(),
+            "path = os.path.join(os.path.dirname(os.path.abspath(__file__)), '{}')",
+            core_file_name,
         );
         uwriteln!(
             self.gen.init,