Fix component model bugs in wasmparser and wasm-compose. (#935)

* wasmparser: fix component validation for type instantiation arguments.

This commit fixes validation when a component is instantiated that imports a
type and the type is provided as an instantiation argument.

Previously, the type was being ignored and not populated in the list of
instantiation arguments, resulting in an incorrect validation message of
"instantiation argument not provided".

The fix is to add type arguments to the arguments list.

* wasm-compose: fix incorrect type indexes caused by type imports.

Currently `wasm-compose` writes all core and component types out in
contiguous sections.

The problem with this approach is that imports of types occur *after* these
sections, so an import of a type will be assigned an incorrect type index.

The fix is to simply encode core types, component types, and imports as
encountered rather than trying to group them all into the same section.

crates/wasm-compose/src/encoding.rs

@@ -72,21 +72,27 @@ impl Encodable for InstanceType {
     }
 }
 
-impl Encodable for (&mut CoreTypeSection, &mut ComponentTypeSection) {
+struct EncodableEntityType<'a> {
+    start_type_count: u32,
+    core_types: &'a mut CoreTypeSection,
+    component_types: &'a mut ComponentTypeSection,
+}
+
+impl<'a> Encodable for EncodableEntityType<'a> {
     fn type_count(&self) -> u32 {
-        self.1.len()
+        self.start_type_count + self.component_types.len()
     }
 
     fn core_type_count(&self) -> u32 {
-        self.0.len()
+        self.core_types.len()
     }
 
     fn ty(&mut self) -> ComponentTypeEncoder {
-        self.1.ty()
+        self.component_types.ty()
     }
 
     fn core_type(&mut self) -> CoreTypeEncoder {
-        self.0.ty()
+        self.core_types.ty()
     }
 }
 
@@ -132,12 +138,12 @@ impl<'a> TypeEncoder<'a> {
         let mut types = TypeMap::new();
 
         for (name, url, ty) in imports {
-            let ty = self.encodable_component_entity_type(&mut encoded, &mut types, ty);
+            let ty = self.component_entity_type(&mut encoded, &mut types, ty);
             encoded.import(name, url, ty);
         }
 
         for (name, url, ty) in exports {
-            let ty = self.encodable_component_entity_type(&mut encoded, &mut types, ty);
+            let ty = self.component_entity_type(&mut encoded, &mut types, ty);
             encoded.export(name, url, ty);
         }
 
@@ -152,7 +158,7 @@ impl<'a> TypeEncoder<'a> {
         let mut types = TypeMap::new();
 
         for (name, url, ty) in exports {
-            let ty = self.encodable_component_entity_type(&mut encoded, &mut types, ty);
+            let ty = self.component_entity_type(&mut encoded, &mut types, ty);
             encoded.export(name, url, ty);
         }
 
@@ -180,17 +186,6 @@ impl<'a> TypeEncoder<'a> {
         encoded
     }
 
-    pub fn component_entity_type(
-        &self,
-        core_types: &mut CoreTypeSection,
-        component_types: &mut ComponentTypeSection,
-        types: &mut TypeMap<'a>,
-        ty: wasmparser::types::ComponentEntityType,
-    ) -> ComponentTypeRef {
-        let mut encodable = (core_types, component_types);
-        self.encodable_component_entity_type(&mut encodable, types, ty)
-    }
-
     fn entity_type(
         &self,
         encodable: &mut ModuleType,
@@ -239,7 +234,7 @@ impl<'a> TypeEncoder<'a> {
         }
     }
 
-    fn encodable_component_entity_type(
+    fn component_entity_type(
         &self,
         encodable: &mut impl Encodable,
         types: &mut TypeMap<'a>,
@@ -988,14 +983,6 @@ impl<'a> ImportMap<'a> {
     }
 }
 
-#[derive(Default)]
-struct ImportEncodingContext<'a> {
-    types: TypeMap<'a>,
-    import_section: ComponentImportSection,
-    core_type_section: CoreTypeSection,
-    type_section: ComponentTypeSection,
-}
-
 /// Used to encode a composition graph as a new WebAssembly component.
 pub(crate) struct CompositionGraphEncoder<'a> {
     /// The options for the encoding.
@@ -1063,28 +1050,25 @@ impl<'a> CompositionGraphEncoder<'a> {
 
     fn encode_imports(&mut self, encoded: &mut Component) -> Result<()> {
         let imports = ImportMap::new(!self.options.define_components, self.graph)?;
-        let mut context = ImportEncodingContext::default();
-
+        let mut type_map = TypeMap::default();
         for (name, entry) in imports.0 {
             match entry {
                 ImportMapEntry::Component(component) => {
-                    self.encode_component_import(&mut context, name.as_ref(), "", component);
+                    self.encode_component_import(encoded, name.as_ref(), "", component);
                 }
                 ImportMapEntry::Argument(arg) => {
                     let index = match arg.kind {
                         ArgumentImportKind::Item(component, ty) => self.encode_item_import(
-                            &mut context,
+                            encoded,
+                            &mut type_map,
                             name.as_ref(),
                             arg.url,
                             component,
                             ty,
                         ),
-                        ArgumentImportKind::Instance(exports) => self.encode_instance_import(
-                            &mut context,
-                            name.as_ref(),
-                            arg.url,
-                            exports,
-                        ),
+                        ArgumentImportKind::Instance(exports) => {
+                            self.encode_instance_import(encoded, name.as_ref(), arg.url, exports)
+                        }
                     };
 
                     self.imported_args
@@ -1093,35 +1077,18 @@ impl<'a> CompositionGraphEncoder<'a> {
             }
         }
 
-        if !context.core_type_section.is_empty() {
-            encoded.section(&context.core_type_section);
-        }
-
-        if !context.type_section.is_empty() {
-            encoded.section(&context.type_section);
-        }
-
-        if !context.import_section.is_empty() {
-            encoded.section(&context.import_section);
-        }
-
         Ok(())
     }
 
     fn encode_component_import(
         &mut self,
-        context: &mut ImportEncodingContext<'a>,
+        encoded: &mut Component,
         name: &str,
         url: &str,
         component: &'a crate::graph::Component,
     ) -> u32 {
-        let type_index = self.define_component_type(&mut context.type_section, component);
-        let index = self.import(
-            &mut context.import_section,
-            name,
-            url,
-            ComponentTypeRef::Component(type_index),
-        );
+        let type_index = self.define_component_type(encoded, component);
+        let index = self.import(encoded, name, url, ComponentTypeRef::Component(type_index));
 
         assert!(self
             .encoded_components
@@ -1133,29 +1100,40 @@ impl<'a> CompositionGraphEncoder<'a> {
 
     fn encode_item_import(
         &mut self,
-        context: &mut ImportEncodingContext<'a>,
+        encoded: &mut Component,
+        type_map: &mut TypeMap<'a>,
         name: &str,
         url: &str,
         component: &'a crate::graph::Component,
         ty: ComponentEntityType,
     ) -> u32 {
-        let prev_type_count = context.type_section.len();
+        let mut core_type_section = CoreTypeSection::new();
+        let mut type_section = ComponentTypeSection::new();
 
         let encoder = TypeEncoder::new(&component.types);
-        let ty = encoder.component_entity_type(
-            &mut context.core_type_section,
-            &mut context.type_section,
-            &mut context.types,
-            ty,
-        );
 
-        self.types += context.type_section.len() - prev_type_count;
-        self.import(&mut context.import_section, name, url, ty)
+        let mut encodable = EncodableEntityType {
+            start_type_count: self.types,
+            core_types: &mut core_type_section,
+            component_types: &mut type_section,
+        };
+        let ty = encoder.component_entity_type(&mut encodable, type_map, ty);
+
+        if !core_type_section.is_empty() {
+            encoded.section(&core_type_section);
+        }
+
+        if !type_section.is_empty() {
+            encoded.section(&type_section);
+            self.types += type_section.len();
+        }
+
+        self.import(encoded, name, url, ty)
     }
 
     fn encode_instance_import(
         &mut self,
-        context: &mut ImportEncodingContext<'a>,
+        encoded: &mut Component,
         name: &str,
         url: &str,
         exports: IndexMap<&'a str, (&'a str, &'a crate::graph::Component, ComponentEntityType)>,
@@ -1164,20 +1142,17 @@ impl<'a> CompositionGraphEncoder<'a> {
         let mut types = TypeMap::new();
         for (name, (url, component, ty)) in exports {
             let encoder = TypeEncoder::new(&component.types);
-            let ty = encoder.encodable_component_entity_type(&mut instance_type, &mut types, ty);
+            let ty = encoder.component_entity_type(&mut instance_type, &mut types, ty);
             instance_type.export(name, url, ty);
         }
 
         let index = self.types;
-        context.type_section.instance(&instance_type);
+        let mut type_section = ComponentTypeSection::new();
+        type_section.instance(&instance_type);
+        encoded.section(&type_section);
         self.types += 1;
 
-        self.import(
-            &mut context.import_section,
-            name,
-            url,
-            ComponentTypeRef::Instance(index),
-        )
+        self.import(encoded, name, url, ComponentTypeRef::Instance(index))
     }
 
     fn encode_instantiations(&mut self, encoded: &mut Component) -> Result<()> {
@@ -1306,11 +1281,14 @@ impl<'a> CompositionGraphEncoder<'a> {
 
     fn define_component_type(
         &mut self,
-        type_section: &mut ComponentTypeSection,
+        encoded: &mut Component,
         component: &crate::graph::Component,
     ) -> u32 {
-        let type_index = self.types;
+        let mut type_section = ComponentTypeSection::new();
         type_section.component(&component.ty());
+        encoded.section(&type_section);
+
+        let type_index = self.types;
         self.types += 1;
         type_index
     }
@@ -1398,7 +1376,7 @@ impl<'a> CompositionGraphEncoder<'a> {
 
     fn import(
         &mut self,
-        import_section: &mut ComponentImportSection,
+        encoded: &mut Component,
         name: &str,
         url: &str,
         ty: ComponentTypeRef,
@@ -1414,7 +1392,9 @@ impl<'a> CompositionGraphEncoder<'a> {
 
         log::debug!("importing {desc} with `{name}` (encoded index {count}) in composed component");
 
+        let mut import_section = ComponentImportSection::new();
         import_section.import(name, url, ty);
+        encoded.section(&import_section);
 
         let index = *count;
         *count += 1;