chore: checkpoint before Python removal

vendor/wasm-encoder/src/component.rs

@@ -0,0 +1,169 @@
+mod aliases;
+mod builder;
+mod canonicals;
+mod components;
+mod exports;
+mod imports;
+mod instances;
+mod modules;
+mod names;
+mod start;
+mod types;
+
+pub use self::aliases::*;
+pub use self::builder::*;
+pub use self::canonicals::*;
+pub use self::components::*;
+pub use self::exports::*;
+pub use self::imports::*;
+pub use self::instances::*;
+pub use self::modules::*;
+pub use self::names::*;
+pub use self::start::*;
+pub use self::types::*;
+
+use crate::{CustomSection, Encode, ProducersSection, RawCustomSection};
+use alloc::vec::Vec;
+
+// Core sorts extended by the component model
+const CORE_TYPE_SORT: u8 = 0x10;
+const CORE_MODULE_SORT: u8 = 0x11;
+const CORE_INSTANCE_SORT: u8 = 0x12;
+
+const CORE_SORT: u8 = 0x00;
+const FUNCTION_SORT: u8 = 0x01;
+const VALUE_SORT: u8 = 0x02;
+const TYPE_SORT: u8 = 0x03;
+const COMPONENT_SORT: u8 = 0x04;
+const INSTANCE_SORT: u8 = 0x05;
+
+/// A WebAssembly component section.
+///
+/// Various builders defined in this crate already implement this trait, but you
+/// can also implement it yourself for your own custom section builders, or use
+/// `RawSection` to use a bunch of raw bytes as a section.
+pub trait ComponentSection: Encode {
+    /// Gets the section identifier for this section.
+    fn id(&self) -> u8;
+
+    /// Appends this section to the specified destination list of bytes.
+    fn append_to_component(&self, dst: &mut Vec<u8>) {
+        dst.push(self.id());
+        self.encode(dst);
+    }
+}
+
+/// Known section identifiers of WebAssembly components.
+///
+/// These sections are supported by the component model proposal.
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd)]
+#[repr(u8)]
+pub enum ComponentSectionId {
+    /// The section is a core custom section.
+    CoreCustom = 0,
+    /// The section is a core module section.
+    CoreModule = 1,
+    /// The section is a core instance section.
+    CoreInstance = 2,
+    /// The section is a core type section.
+    CoreType = 3,
+    /// The section is a component section.
+    Component = 4,
+    /// The section is an instance section.
+    Instance = 5,
+    /// The section is an alias section.
+    Alias = 6,
+    /// The section is a type section.
+    Type = 7,
+    /// The section is a canonical function section.
+    CanonicalFunction = 8,
+    /// The section is a start section.
+    Start = 9,
+    /// The section is an import section.
+    Import = 10,
+    /// The section is an export section.
+    Export = 11,
+}
+
+impl From<ComponentSectionId> for u8 {
+    #[inline]
+    fn from(id: ComponentSectionId) -> u8 {
+        id as u8
+    }
+}
+
+impl Encode for ComponentSectionId {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        sink.push(*self as u8);
+    }
+}
+
+/// Represents a WebAssembly component that is being encoded.
+///
+/// Unlike core WebAssembly modules, the sections of a component
+/// may appear in any order and may be repeated.
+///
+/// Components may also added as a section to other components.
+#[derive(Clone, Debug)]
+pub struct Component {
+    bytes: Vec<u8>,
+}
+
+impl Component {
+    /// The 8-byte header at the beginning of all components.
+    #[rustfmt::skip]
+    pub const HEADER: [u8; 8] = [
+        // Magic
+        0x00, 0x61, 0x73, 0x6D,
+        // Version
+        0x0d, 0x00, 0x01, 0x00,
+    ];
+
+    /// Begin writing a new `Component`.
+    pub fn new() -> Self {
+        Self {
+            bytes: Self::HEADER.to_vec(),
+        }
+    }
+
+    /// Finish writing this component and extract ownership of the encoded bytes.
+    pub fn finish(self) -> Vec<u8> {
+        self.bytes
+    }
+
+    /// Write a section to this component.
+    pub fn section(&mut self, section: &impl ComponentSection) -> &mut Self {
+        self.bytes.push(section.id());
+        section.encode(&mut self.bytes);
+        self
+    }
+
+    /// View the encoded bytes.
+    pub fn as_slice(&self) -> &[u8] {
+        &self.bytes
+    }
+}
+
+impl Default for Component {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl ComponentSection for CustomSection<'_> {
+    fn id(&self) -> u8 {
+        ComponentSectionId::CoreCustom.into()
+    }
+}
+
+impl ComponentSection for RawCustomSection<'_> {
+    fn id(&self) -> u8 {
+        ComponentSectionId::CoreCustom.into()
+    }
+}
+
+impl ComponentSection for ProducersSection {
+    fn id(&self) -> u8 {
+        ComponentSectionId::CoreCustom.into()
+    }
+}

vendor/wasm-encoder/src/component/aliases.rs

@@ -0,0 +1,161 @@
+use super::{COMPONENT_SORT, CORE_MODULE_SORT, CORE_SORT, CORE_TYPE_SORT, TYPE_SORT};
+use crate::{
+    ComponentExportKind, ComponentSection, ComponentSectionId, Encode, ExportKind, encode_section,
+};
+use alloc::vec::Vec;
+
+/// Represents the kinds of outer aliasable items in a component.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum ComponentOuterAliasKind {
+    /// The alias is to a core module.
+    CoreModule,
+    /// The alias is to a core type.
+    CoreType,
+    /// The alias is to a type.
+    Type,
+    /// The alias is to a component.
+    Component,
+}
+
+impl Encode for ComponentOuterAliasKind {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            Self::CoreModule => {
+                sink.push(CORE_SORT);
+                sink.push(CORE_MODULE_SORT);
+            }
+            Self::CoreType => {
+                sink.push(CORE_SORT);
+                sink.push(CORE_TYPE_SORT);
+            }
+            Self::Type => sink.push(TYPE_SORT),
+            Self::Component => sink.push(COMPONENT_SORT),
+        }
+    }
+}
+
+/// An encoder for the alias section of WebAssembly component.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{Component, Alias, ComponentAliasSection, ComponentExportKind, ComponentOuterAliasKind};
+///
+/// let mut aliases = ComponentAliasSection::new();
+/// aliases.alias(Alias::InstanceExport { instance: 0, kind: ComponentExportKind::Func, name: "f" });
+/// aliases.alias(Alias::Outer { count: 0, kind: ComponentOuterAliasKind::Type, index: 1 });
+///
+/// let mut component = Component::new();
+/// component.section(&aliases);
+///
+/// let bytes = component.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct ComponentAliasSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+/// Different forms of aliases that can be inserted into a
+/// [`ComponentAliasSection`].
+#[derive(Copy, Clone, Debug)]
+pub enum Alias<'a> {
+    /// An alias of a component instance export.
+    InstanceExport {
+        /// The index of the component instance that's being aliased from.
+        instance: u32,
+        /// The kind of item that's being extracted from the component
+        /// instance.
+        kind: ComponentExportKind,
+        /// The name of the export that's being aliased.
+        name: &'a str,
+    },
+    /// Same as `InstanceExport`, but for core instances.
+    #[allow(missing_docs)]
+    CoreInstanceExport {
+        instance: u32,
+        kind: ExportKind,
+        name: &'a str,
+    },
+    /// Aliasing an item from an outer component.
+    Outer {
+        /// The kind of item being aliased, either a type or a component.
+        kind: ComponentOuterAliasKind,
+        /// Number of levels "up" to go to lookup the index within. Level 0 is
+        /// the current scope and level 1 is the enclosing scope, and so on.
+        count: u32,
+        /// The index of the item to alias within the scope referenced by
+        /// `count`.
+        index: u32,
+    },
+}
+
+impl ComponentAliasSection {
+    /// Create a new alias section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of aliases in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define an alias to a component instance's export.
+    pub fn alias(&mut self, alias: Alias<'_>) -> &mut Self {
+        alias.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for ComponentAliasSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl ComponentSection for ComponentAliasSection {
+    fn id(&self) -> u8 {
+        ComponentSectionId::Alias.into()
+    }
+}
+
+impl Encode for Alias<'_> {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            Alias::InstanceExport {
+                instance,
+                kind,
+                name,
+            } => {
+                kind.encode(sink);
+                sink.push(0x00);
+                instance.encode(sink);
+                name.encode(sink);
+            }
+            Alias::CoreInstanceExport {
+                instance,
+                kind,
+                name,
+            } => {
+                sink.push(CORE_SORT);
+                kind.encode(sink);
+                sink.push(0x01);
+                instance.encode(sink);
+                name.encode(sink);
+            }
+            Alias::Outer { kind, count, index } => {
+                kind.encode(sink);
+                sink.push(0x02);
+                count.encode(sink);
+                index.encode(sink);
+            }
+        }
+    }
+}

vendor/wasm-encoder/src/component/builder.rs

@@ -0,0 +1,826 @@
+use crate::component::*;
+use crate::{ExportKind, Module, NameMap, RawSection, ValType};
+use alloc::format;
+use alloc::vec::Vec;
+use core::mem;
+
+/// Convenience type to build a component incrementally and automatically keep
+/// track of index spaces.
+///
+/// This type is intended to be a wrapper around the [`Component`] encoding type
+/// which is useful for building it up incrementally over time. This type will
+/// automatically collect definitions into sections and reports the index of all
+/// items added by keeping track of indices internally.
+#[derive(Debug, Default)]
+pub struct ComponentBuilder {
+    /// The binary component that's being built.
+    component: Component,
+
+    /// The last section which was appended to during encoding. This type is
+    /// generated by the `section_accessors` macro below.
+    ///
+    /// When something is encoded this is used if it matches the kind of item
+    /// being encoded, otherwise it's "flushed" to the output component and a
+    /// new section is started.
+    last_section: LastSection,
+
+    // Core index spaces
+    core_modules: Namespace,
+    core_funcs: Namespace,
+    core_types: Namespace,
+    core_memories: Namespace,
+    core_tables: Namespace,
+    core_instances: Namespace,
+    core_tags: Namespace,
+    core_globals: Namespace,
+
+    // Component index spaces
+    funcs: Namespace,
+    instances: Namespace,
+    types: Namespace,
+    components: Namespace,
+    values: Namespace,
+}
+
+impl ComponentBuilder {
+    /// Returns the current number of core modules.
+    pub fn core_module_count(&self) -> u32 {
+        self.core_modules.count
+    }
+
+    /// Returns the current number of core funcs.
+    pub fn core_func_count(&self) -> u32 {
+        self.core_funcs.count
+    }
+
+    /// Returns the current number of core types.
+    pub fn core_type_count(&self) -> u32 {
+        self.core_types.count
+    }
+
+    /// Returns the current number of core memories.
+    pub fn core_memory_count(&self) -> u32 {
+        self.core_memories.count
+    }
+
+    /// Returns the current number of core tables.
+    pub fn core_table_count(&self) -> u32 {
+        self.core_tables.count
+    }
+
+    /// Returns the current number of core instances.
+    pub fn core_instance_count(&self) -> u32 {
+        self.core_instances.count
+    }
+
+    /// Returns the current number of core tags.
+    pub fn core_tag_count(&self) -> u32 {
+        self.core_tags.count
+    }
+
+    /// Returns the current number of core globals.
+    pub fn core_global_count(&self) -> u32 {
+        self.core_globals.count
+    }
+
+    /// Returns the current number of component funcs.
+    pub fn func_count(&self) -> u32 {
+        self.funcs.count
+    }
+
+    /// Returns the current number of component instances.
+    pub fn instance_count(&self) -> u32 {
+        self.instances.count
+    }
+
+    /// Returns the current number of component values.
+    pub fn value_count(&self) -> u32 {
+        self.values.count
+    }
+
+    /// Returns the current number of components.
+    pub fn component_count(&self) -> u32 {
+        self.components.count
+    }
+
+    /// Returns the current number of component types.
+    pub fn type_count(&self) -> u32 {
+        self.types.count
+    }
+
+    /// Add all debug names registered to the component.
+    pub fn append_names(&mut self) {
+        let mut names = ComponentNameSection::new();
+        if !self.core_funcs.names.is_empty() {
+            names.core_funcs(&self.core_funcs.names);
+        }
+        if !self.core_tables.names.is_empty() {
+            names.core_tables(&self.core_tables.names);
+        }
+        if !self.core_memories.names.is_empty() {
+            names.core_memories(&self.core_memories.names);
+        }
+        if !self.core_globals.names.is_empty() {
+            names.core_globals(&self.core_globals.names);
+        }
+        if !self.core_tags.names.is_empty() {
+            names.core_tags(&self.core_tags.names);
+        }
+        if !self.core_types.names.is_empty() {
+            names.core_types(&self.core_types.names);
+        }
+        if !self.core_modules.names.is_empty() {
+            names.core_modules(&self.core_modules.names);
+        }
+        if !self.core_instances.names.is_empty() {
+            names.core_instances(&self.core_instances.names);
+        }
+        if !self.instances.names.is_empty() {
+            names.instances(&self.instances.names);
+        }
+        if !self.funcs.names.is_empty() {
+            names.funcs(&self.funcs.names);
+        }
+        if !self.types.names.is_empty() {
+            names.types(&self.types.names);
+        }
+        if !self.components.names.is_empty() {
+            names.components(&self.components.names);
+        }
+        if !self.instances.names.is_empty() {
+            names.instances(&self.instances.names);
+        }
+        if !names.is_empty() {
+            self.custom_section(&names.as_custom());
+        }
+    }
+
+    /// Completes this component and returns the binary encoding of the entire
+    /// component.
+    pub fn finish(mut self) -> Vec<u8> {
+        self.flush();
+        self.component.finish()
+    }
+
+    /// Encodes a core wasm `Module` into this component, returning its index.
+    pub fn core_module(&mut self, debug_name: Option<&str>, module: &Module) -> u32 {
+        self.flush();
+        self.component.section(&ModuleSection(module));
+        self.core_modules.add(debug_name)
+    }
+
+    /// Encodes a core wasm `module` into this component, returning its index.
+    pub fn core_module_raw(&mut self, debug_name: Option<&str>, module: &[u8]) -> u32 {
+        self.flush();
+        self.component.section(&RawSection {
+            id: ComponentSectionId::CoreModule.into(),
+            data: module,
+        });
+        self.core_modules.add(debug_name)
+    }
+
+    /// Instantiates a core wasm module at `module_index` with the `args`
+    /// provided.
+    ///
+    /// Returns the index of the core wasm instance created.
+    pub fn core_instantiate<'a, A>(
+        &mut self,
+        debug_name: Option<&str>,
+        module_index: u32,
+        args: A,
+    ) -> u32
+    where
+        A: IntoIterator<Item = (&'a str, ModuleArg)>,
+        A::IntoIter: ExactSizeIterator,
+    {
+        self.instances().instantiate(module_index, args);
+        self.core_instances.add(debug_name)
+    }
+
+    /// Creates a new core wasm instance from the `exports` provided.
+    ///
+    /// Returns the index of the core wasm instance created.
+    pub fn core_instantiate_exports<'a, E>(&mut self, debug_name: Option<&str>, exports: E) -> u32
+    where
+        E: IntoIterator<Item = (&'a str, ExportKind, u32)>,
+        E::IntoIter: ExactSizeIterator,
+    {
+        self.instances().export_items(exports);
+        self.core_instances.add(debug_name)
+    }
+
+    /// Creates a new aliased item where the core `instance` specified has its
+    /// export `name` aliased out with the `kind` specified.
+    ///
+    /// Returns the index of the item created.
+    pub fn core_alias_export(
+        &mut self,
+        debug_name: Option<&str>,
+        instance: u32,
+        name: &str,
+        kind: ExportKind,
+    ) -> u32 {
+        self.alias(
+            debug_name,
+            Alias::CoreInstanceExport {
+                instance,
+                kind,
+                name,
+            },
+        )
+    }
+
+    /// Adds a new alias to this component
+    pub fn alias(&mut self, debug_name: Option<&str>, alias: Alias<'_>) -> u32 {
+        self.aliases().alias(alias);
+        match alias {
+            Alias::InstanceExport { kind, .. } => self.inc_kind(debug_name, kind),
+            Alias::CoreInstanceExport { kind, .. } => self.inc_core_kind(debug_name, kind),
+            Alias::Outer {
+                kind: ComponentOuterAliasKind::Type,
+                ..
+            } => self.types.add(debug_name),
+            Alias::Outer {
+                kind: ComponentOuterAliasKind::CoreModule,
+                ..
+            } => self.core_modules.add(debug_name),
+            Alias::Outer {
+                kind: ComponentOuterAliasKind::Component,
+                ..
+            } => self.components.add(debug_name),
+            Alias::Outer {
+                kind: ComponentOuterAliasKind::CoreType,
+                ..
+            } => self.core_types.add(debug_name),
+        }
+    }
+
+    /// Creates an alias to a previous component instance's exported item.
+    ///
+    /// The `instance` provided is the instance to access and the `name` is the
+    /// item to access.
+    ///
+    /// Returns the index of the new item defined.
+    pub fn alias_export(&mut self, instance: u32, name: &str, kind: ComponentExportKind) -> u32 {
+        self.alias(
+            Some(name),
+            Alias::InstanceExport {
+                instance,
+                kind,
+                name,
+            },
+        )
+    }
+
+    fn inc_kind(&mut self, debug_name: Option<&str>, kind: ComponentExportKind) -> u32 {
+        match kind {
+            ComponentExportKind::Func => self.funcs.add(debug_name),
+            ComponentExportKind::Module => self.core_modules.add(debug_name),
+            ComponentExportKind::Type => self.types.add(debug_name),
+            ComponentExportKind::Component => self.components.add(debug_name),
+            ComponentExportKind::Instance => self.instances.add(debug_name),
+            ComponentExportKind::Value => self.values.add(debug_name),
+        }
+    }
+
+    fn inc_core_kind(&mut self, debug_name: Option<&str>, kind: ExportKind) -> u32 {
+        match kind {
+            ExportKind::Func => self.core_funcs.add(debug_name),
+            ExportKind::Table => self.core_tables.add(debug_name),
+            ExportKind::Memory => self.core_memories.add(debug_name),
+            ExportKind::Global => self.core_globals.add(debug_name),
+            ExportKind::Tag => self.core_tags.add(debug_name),
+        }
+    }
+
+    /// Lowers the `func_index` component function into a core wasm function
+    /// using the `options` provided.
+    ///
+    /// Returns the index of the core wasm function created.
+    pub fn lower_func<O>(&mut self, debug_name: Option<&str>, func_index: u32, options: O) -> u32
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.canonical_functions().lower(func_index, options);
+        self.core_funcs.add(debug_name)
+    }
+
+    /// Lifts the core wasm `core_func_index` function with the component
+    /// function type `type_index` and `options`.
+    ///
+    /// Returns the index of the component function created.
+    pub fn lift_func<O>(
+        &mut self,
+        debug_name: Option<&str>,
+        core_func_index: u32,
+        type_index: u32,
+        options: O,
+    ) -> u32
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.canonical_functions()
+            .lift(core_func_index, type_index, options);
+        self.funcs.add(debug_name)
+    }
+
+    /// Imports a new item into this component with the `name` and `ty` specified.
+    pub fn import(&mut self, name: &str, ty: ComponentTypeRef) -> u32 {
+        let ret = match &ty {
+            ComponentTypeRef::Instance(_) => self.instances.add(Some(name)),
+            ComponentTypeRef::Func(_) => self.funcs.add(Some(name)),
+            ComponentTypeRef::Type(..) => self.types.add(Some(name)),
+            ComponentTypeRef::Component(_) => self.components.add(Some(name)),
+            ComponentTypeRef::Module(_) => self.core_modules.add(Some(name)),
+            ComponentTypeRef::Value(_) => self.values.add(Some(name)),
+        };
+        self.imports().import(name, ty);
+        ret
+    }
+
+    /// Exports a new item from this component with the `name` and `kind`
+    /// specified.
+    ///
+    /// The `idx` is the item to export and the `ty` is an optional type to
+    /// ascribe to the export.
+    pub fn export(
+        &mut self,
+        name: &str,
+        kind: ComponentExportKind,
+        idx: u32,
+        ty: Option<ComponentTypeRef>,
+    ) -> u32 {
+        self.exports().export(name, kind, idx, ty);
+        self.inc_kind(Some(name), kind)
+    }
+
+    /// Creates a new encoder for the next core type in this component.
+    pub fn core_type(&mut self, debug_name: Option<&str>) -> (u32, ComponentCoreTypeEncoder<'_>) {
+        (self.core_types.add(debug_name), self.core_types().ty())
+    }
+
+    /// Creates a new encoder for the next type in this component.
+    pub fn ty(&mut self, debug_name: Option<&str>) -> (u32, ComponentTypeEncoder<'_>) {
+        (self.types.add(debug_name), self.types().ty())
+    }
+
+    /// Creates a new instance type within this component.
+    pub fn type_instance(&mut self, debug_name: Option<&str>, ty: &InstanceType) -> u32 {
+        self.types().instance(ty);
+        self.types.add(debug_name)
+    }
+
+    /// Creates a new component type within this component.
+    pub fn type_component(&mut self, debug_name: Option<&str>, ty: &ComponentType) -> u32 {
+        self.types().component(ty);
+        self.types.add(debug_name)
+    }
+
+    /// Creates a new defined component type within this component.
+    pub fn type_defined(
+        &mut self,
+        debug_name: Option<&str>,
+    ) -> (u32, ComponentDefinedTypeEncoder<'_>) {
+        (self.types.add(debug_name), self.types().defined_type())
+    }
+
+    /// Creates a new component function type within this component.
+    pub fn type_function(
+        &mut self,
+        debug_name: Option<&str>,
+    ) -> (u32, ComponentFuncTypeEncoder<'_>) {
+        (self.types.add(debug_name), self.types().function())
+    }
+
+    /// Declares a new resource type within this component.
+    pub fn type_resource(
+        &mut self,
+        debug_name: Option<&str>,
+        rep: ValType,
+        dtor: Option<u32>,
+    ) -> u32 {
+        self.types().resource(rep, dtor);
+        self.types.add(debug_name)
+    }
+
+    /// Defines a new subcomponent of this component.
+    pub fn component(&mut self, debug_name: Option<&str>, mut builder: ComponentBuilder) -> u32 {
+        builder.flush();
+        self.flush();
+        self.component
+            .section(&NestedComponentSection(&builder.component));
+        self.components.add(debug_name)
+    }
+
+    /// Defines a new subcomponent of this component.
+    pub fn component_raw(&mut self, debug_name: Option<&str>, data: &[u8]) -> u32 {
+        let raw_section = RawSection {
+            id: ComponentSectionId::Component.into(),
+            data,
+        };
+        self.flush();
+        self.component.section(&raw_section);
+        self.components.add(debug_name)
+    }
+
+    /// Instantiates the `component_index` specified with the `args` specified.
+    pub fn instantiate<A, S>(
+        &mut self,
+        debug_name: Option<&str>,
+        component_index: u32,
+        args: A,
+    ) -> u32
+    where
+        A: IntoIterator<Item = (S, ComponentExportKind, u32)>,
+        A::IntoIter: ExactSizeIterator,
+        S: AsRef<str>,
+    {
+        self.component_instances()
+            .instantiate(component_index, args);
+        self.instances.add(debug_name)
+    }
+
+    /// Declares a new `resource.drop` intrinsic.
+    pub fn resource_drop(&mut self, ty: u32) -> u32 {
+        self.canonical_functions().resource_drop(ty);
+        self.core_funcs.add(Some("resource.drop"))
+    }
+
+    /// Declares a new `resource.drop` intrinsic.
+    pub fn resource_drop_async(&mut self, ty: u32) -> u32 {
+        self.canonical_functions().resource_drop_async(ty);
+        self.core_funcs.add(Some("resource.drop async"))
+    }
+
+    /// Declares a new `resource.new` intrinsic.
+    pub fn resource_new(&mut self, ty: u32) -> u32 {
+        self.canonical_functions().resource_new(ty);
+        self.core_funcs.add(Some("resource.new"))
+    }
+
+    /// Declares a new `resource.rep` intrinsic.
+    pub fn resource_rep(&mut self, ty: u32) -> u32 {
+        self.canonical_functions().resource_rep(ty);
+        self.core_funcs.add(Some("resource.rep"))
+    }
+
+    /// Declares a new `thread.spawn_ref` intrinsic.
+    pub fn thread_spawn_ref(&mut self, ty: u32) -> u32 {
+        self.canonical_functions().thread_spawn_ref(ty);
+        self.core_funcs.add(Some("thread.spawn-ref"))
+    }
+
+    /// Declares a new `thread.available_parallelism` intrinsic.
+    pub fn thread_available_parallelism(&mut self) -> u32 {
+        self.canonical_functions().thread_available_parallelism();
+        self.core_funcs.add(Some("thread.available-parallelism"))
+    }
+
+    /// Declares a new `backpressure.inc` intrinsic.
+    pub fn backpressure_inc(&mut self) -> u32 {
+        self.canonical_functions().backpressure_inc();
+        self.core_funcs.add(Some("backpressure.inc"))
+    }
+
+    /// Declares a new `backpressure.dec` intrinsic.
+    pub fn backpressure_dec(&mut self) -> u32 {
+        self.canonical_functions().backpressure_dec();
+        self.core_funcs.add(Some("backpressure.dec"))
+    }
+
+    /// Declares a new `task.return` intrinsic.
+    pub fn task_return<O>(&mut self, ty: Option<ComponentValType>, options: O) -> u32
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.canonical_functions().task_return(ty, options);
+        self.core_funcs.add(Some("task.return"))
+    }
+
+    /// Declares a new `task.cancel` intrinsic.
+    pub fn task_cancel(&mut self) -> u32 {
+        self.canonical_functions().task_cancel();
+        self.core_funcs.add(Some("task.cancel"))
+    }
+
+    /// Declares a new `context.get` intrinsic.
+    pub fn context_get(&mut self, i: u32) -> u32 {
+        self.canonical_functions().context_get(i);
+        self.core_funcs.add(Some(&format!("context.get {i}")))
+    }
+
+    /// Declares a new `context.set` intrinsic.
+    pub fn context_set(&mut self, i: u32) -> u32 {
+        self.canonical_functions().context_set(i);
+        self.core_funcs.add(Some(&format!("context.set {i}")))
+    }
+
+    /// Declares a new `thread.yield` intrinsic.
+    pub fn thread_yield(&mut self, cancellable: bool) -> u32 {
+        self.canonical_functions().thread_yield(cancellable);
+        self.core_funcs.add(Some("thread.yield"))
+    }
+
+    /// Declares a new `subtask.drop` intrinsic.
+    pub fn subtask_drop(&mut self) -> u32 {
+        self.canonical_functions().subtask_drop();
+        self.core_funcs.add(Some("subtask.drop"))
+    }
+
+    /// Declares a new `subtask.cancel` intrinsic.
+    pub fn subtask_cancel(&mut self, async_: bool) -> u32 {
+        self.canonical_functions().subtask_cancel(async_);
+        self.core_funcs.add(Some("subtask.cancel"))
+    }
+
+    /// Declares a new `stream.new` intrinsic.
+    pub fn stream_new(&mut self, ty: u32) -> u32 {
+        self.canonical_functions().stream_new(ty);
+        self.core_funcs.add(Some("stream.new"))
+    }
+
+    /// Declares a new `stream.read` intrinsic.
+    pub fn stream_read<O>(&mut self, ty: u32, options: O) -> u32
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.canonical_functions().stream_read(ty, options);
+        self.core_funcs.add(Some("stream.read"))
+    }
+
+    /// Declares a new `stream.write` intrinsic.
+    pub fn stream_write<O>(&mut self, ty: u32, options: O) -> u32
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.canonical_functions().stream_write(ty, options);
+        self.core_funcs.add(Some("stream.write"))
+    }
+
+    /// Declares a new `stream.cancel-read` intrinsic.
+    pub fn stream_cancel_read(&mut self, ty: u32, async_: bool) -> u32 {
+        self.canonical_functions().stream_cancel_read(ty, async_);
+        self.core_funcs.add(Some("stream.cancel-read"))
+    }
+
+    /// Declares a new `stream.cancel-write` intrinsic.
+    pub fn stream_cancel_write(&mut self, ty: u32, async_: bool) -> u32 {
+        self.canonical_functions().stream_cancel_write(ty, async_);
+        self.core_funcs.add(Some("stream.cancel-write"))
+    }
+
+    /// Declares a new `stream.drop-readable` intrinsic.
+    pub fn stream_drop_readable(&mut self, ty: u32) -> u32 {
+        self.canonical_functions().stream_drop_readable(ty);
+        self.core_funcs.add(Some("stream.drop-readable"))
+    }
+
+    /// Declares a new `stream.drop-writable` intrinsic.
+    pub fn stream_drop_writable(&mut self, ty: u32) -> u32 {
+        self.canonical_functions().stream_drop_writable(ty);
+        self.core_funcs.add(Some("stream.drop-writable"))
+    }
+
+    /// Declares a new `future.new` intrinsic.
+    pub fn future_new(&mut self, ty: u32) -> u32 {
+        self.canonical_functions().future_new(ty);
+        self.core_funcs.add(Some("future.new"))
+    }
+
+    /// Declares a new `future.read` intrinsic.
+    pub fn future_read<O>(&mut self, ty: u32, options: O) -> u32
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.canonical_functions().future_read(ty, options);
+        self.core_funcs.add(Some("future.read"))
+    }
+
+    /// Declares a new `future.write` intrinsic.
+    pub fn future_write<O>(&mut self, ty: u32, options: O) -> u32
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.canonical_functions().future_write(ty, options);
+        self.core_funcs.add(Some("future.write"))
+    }
+
+    /// Declares a new `future.cancel-read` intrinsic.
+    pub fn future_cancel_read(&mut self, ty: u32, async_: bool) -> u32 {
+        self.canonical_functions().future_cancel_read(ty, async_);
+        self.core_funcs.add(Some("future.cancel-read"))
+    }
+
+    /// Declares a new `future.cancel-write` intrinsic.
+    pub fn future_cancel_write(&mut self, ty: u32, async_: bool) -> u32 {
+        self.canonical_functions().future_cancel_write(ty, async_);
+        self.core_funcs.add(Some("future.cancel-write"))
+    }
+
+    /// Declares a new `future.drop-readable` intrinsic.
+    pub fn future_drop_readable(&mut self, ty: u32) -> u32 {
+        self.canonical_functions().future_drop_readable(ty);
+        self.core_funcs.add(Some("future.drop-readable"))
+    }
+
+    /// Declares a new `future.drop-writable` intrinsic.
+    pub fn future_drop_writable(&mut self, ty: u32) -> u32 {
+        self.canonical_functions().future_drop_writable(ty);
+        self.core_funcs.add(Some("future.drop-writable"))
+    }
+
+    /// Declares a new `error-context.new` intrinsic.
+    pub fn error_context_new<O>(&mut self, options: O) -> u32
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.canonical_functions().error_context_new(options);
+        self.core_funcs.add(Some("error-context.new"))
+    }
+
+    /// Declares a new `error-context.debug-message` intrinsic.
+    pub fn error_context_debug_message<O>(&mut self, options: O) -> u32
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.canonical_functions()
+            .error_context_debug_message(options);
+        self.core_funcs.add(Some("error-context.debug-message"))
+    }
+
+    /// Declares a new `error-context.drop` intrinsic.
+    pub fn error_context_drop(&mut self) -> u32 {
+        self.canonical_functions().error_context_drop();
+        self.core_funcs.add(Some("error-context.drop"))
+    }
+
+    /// Declares a new `waitable-set.new` intrinsic.
+    pub fn waitable_set_new(&mut self) -> u32 {
+        self.canonical_functions().waitable_set_new();
+        self.core_funcs.add(Some("waitable-set.new"))
+    }
+
+    /// Declares a new `waitable-set.wait` intrinsic.
+    pub fn waitable_set_wait(&mut self, cancellable: bool, memory: u32) -> u32 {
+        self.canonical_functions()
+            .waitable_set_wait(cancellable, memory);
+        self.core_funcs.add(Some("waitable-set.wait"))
+    }
+
+    /// Declares a new `waitable-set.poll` intrinsic.
+    pub fn waitable_set_poll(&mut self, cancellable: bool, memory: u32) -> u32 {
+        self.canonical_functions()
+            .waitable_set_poll(cancellable, memory);
+        self.core_funcs.add(Some("waitable-set.poll"))
+    }
+
+    /// Declares a new `waitable-set.drop` intrinsic.
+    pub fn waitable_set_drop(&mut self) -> u32 {
+        self.canonical_functions().waitable_set_drop();
+        self.core_funcs.add(Some("waitable-set.drop"))
+    }
+
+    /// Declares a new `waitable.join` intrinsic.
+    pub fn waitable_join(&mut self) -> u32 {
+        self.canonical_functions().waitable_join();
+        self.core_funcs.add(Some("waitable.join"))
+    }
+
+    /// Declares a new `thread.index` intrinsic.
+    pub fn thread_index(&mut self) -> u32 {
+        self.canonical_functions().thread_index();
+        self.core_funcs.add(Some("thread.index"))
+    }
+
+    /// Declares a new `thread.new-indirect` intrinsic.
+    pub fn thread_new_indirect(&mut self, func_ty_idx: u32, table_index: u32) -> u32 {
+        self.canonical_functions()
+            .thread_new_indirect(func_ty_idx, table_index);
+        self.core_funcs.add(Some("thread.new-indirect"))
+    }
+
+    /// Declares a new `thread.switch-to` intrinsic.
+    pub fn thread_switch_to(&mut self, cancellable: bool) -> u32 {
+        self.canonical_functions().thread_switch_to(cancellable);
+        self.core_funcs.add(Some("thread.switch-to"))
+    }
+
+    /// Declares a new `thread.suspend` intrinsic.
+    pub fn thread_suspend(&mut self, cancellable: bool) -> u32 {
+        self.canonical_functions().thread_suspend(cancellable);
+        self.core_funcs.add(Some("thread.suspend"))
+    }
+
+    /// Declares a new `thread.resume-later` intrinsic.
+    pub fn thread_resume_later(&mut self) -> u32 {
+        self.canonical_functions().thread_resume_later();
+        self.core_funcs.add(Some("thread.resume-later"))
+    }
+
+    /// Declares a new `thread.yield-to` intrinsic.
+    pub fn thread_yield_to(&mut self, cancellable: bool) -> u32 {
+        self.canonical_functions().thread_yield_to(cancellable);
+        self.core_funcs.add(Some("thread.yield-to"))
+    }
+
+    /// Adds a new custom section to this component.
+    pub fn custom_section(&mut self, section: &CustomSection<'_>) {
+        self.flush();
+        self.component.section(section);
+    }
+
+    /// Adds a new custom section to this component.
+    pub fn raw_custom_section(&mut self, section: &[u8]) {
+        self.flush();
+        self.component.section(&RawCustomSection(section));
+    }
+}
+
+// Helper macro to generate methods on `ComponentBuilder` to get specific
+// section encoders that automatically flush and write out prior sections as
+// necessary.
+macro_rules! section_accessors {
+    ($($method:ident => $section:ident)*) => (
+        #[derive(Debug, Default)]
+        enum LastSection {
+            #[default]
+            None,
+            $($section($section),)*
+        }
+
+        impl ComponentBuilder {
+            $(
+                fn $method(&mut self) -> &mut $section {
+                    match &self.last_section {
+                        // The last encoded section matches the section that's
+                        // being requested, so no change is necessary.
+                        LastSection::$section(_) => {}
+
+                        // Otherwise the last section didn't match this section,
+                        // so flush any prior section if needed and start
+                        // encoding the desired section of this method.
+                        _ => {
+                            self.flush();
+                            self.last_section = LastSection::$section($section::new());
+                        }
+                    }
+                    match &mut self.last_section {
+                        LastSection::$section(ret) => ret,
+                        _ => unreachable!()
+                    }
+                }
+            )*
+
+            /// Writes out the last section into the final component binary if
+            /// there is a section specified, otherwise does nothing.
+            fn flush(&mut self) {
+                match mem::take(&mut self.last_section) {
+                    LastSection::None => {}
+                    $(
+                        LastSection::$section(section) => {
+                            self.component.section(&section);
+                        }
+                    )*
+                }
+            }
+
+        }
+    )
+}
+
+section_accessors! {
+    component_instances => ComponentInstanceSection
+    instances => InstanceSection
+    canonical_functions => CanonicalFunctionSection
+    aliases => ComponentAliasSection
+    exports => ComponentExportSection
+    imports => ComponentImportSection
+    types => ComponentTypeSection
+    core_types => CoreTypeSection
+}
+
+#[derive(Debug, Default)]
+struct Namespace {
+    count: u32,
+    names: NameMap,
+}
+
+impl Namespace {
+    fn add(&mut self, name: Option<&str>) -> u32 {
+        let ret = self.count;
+        self.count += 1;
+        if let Some(name) = name {
+            self.names.append(ret, name);
+        }
+        ret
+    }
+}

vendor/wasm-encoder/src/component/canonicals.rs

@@ -0,0 +1,584 @@
+use crate::{ComponentSection, ComponentSectionId, ComponentValType, Encode, encode_section};
+use alloc::vec::Vec;
+
+/// Represents options for canonical function definitions.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum CanonicalOption {
+    /// The string types in the function signature are UTF-8 encoded.
+    UTF8,
+    /// The string types in the function signature are UTF-16 encoded.
+    UTF16,
+    /// The string types in the function signature are compact UTF-16 encoded.
+    CompactUTF16,
+    /// The memory to use if the lifting or lowering of a function requires memory access.
+    ///
+    /// The value is an index to a core memory.
+    Memory(u32),
+    /// The realloc function to use if the lifting or lowering of a function requires memory
+    /// allocation.
+    ///
+    /// The value is an index to a core function of type `(func (param i32 i32 i32 i32) (result i32))`.
+    Realloc(u32),
+    /// The post-return function to use if the lifting of a function requires
+    /// cleanup after the function returns.
+    PostReturn(u32),
+    /// Indicates that specified function should be lifted or lowered using the `async` ABI.
+    Async,
+    /// The function to use if the async lifting of a function should receive task/stream/future progress events
+    /// using a callback.
+    Callback(u32),
+    /// The core function type to lower a component function into.
+    CoreType(u32),
+    /// Use the GC variant of the canonical ABI.
+    Gc,
+}
+
+impl Encode for CanonicalOption {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            Self::UTF8 => sink.push(0x00),
+            Self::UTF16 => sink.push(0x01),
+            Self::CompactUTF16 => sink.push(0x02),
+            Self::Memory(idx) => {
+                sink.push(0x03);
+                idx.encode(sink);
+            }
+            Self::Realloc(idx) => {
+                sink.push(0x04);
+                idx.encode(sink);
+            }
+            Self::PostReturn(idx) => {
+                sink.push(0x05);
+                idx.encode(sink);
+            }
+            Self::Async => {
+                sink.push(0x06);
+            }
+            Self::Callback(idx) => {
+                sink.push(0x07);
+                idx.encode(sink);
+            }
+            Self::CoreType(idx) => {
+                sink.push(0x08);
+                idx.encode(sink);
+            }
+            Self::Gc => {
+                sink.push(0x09);
+            }
+        }
+    }
+}
+
+/// An encoder for the canonical function section of WebAssembly components.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{Component, CanonicalFunctionSection, CanonicalOption};
+///
+/// let mut functions = CanonicalFunctionSection::new();
+/// functions.lift(0, 0, [CanonicalOption::UTF8]);
+///
+/// let mut component = Component::new();
+/// component.section(&functions);
+///
+/// let bytes = component.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct CanonicalFunctionSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl CanonicalFunctionSection {
+    /// Construct a new component function section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of functions in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define a function that will lift a core WebAssembly function to the canonical ABI.
+    pub fn lift<O>(&mut self, core_func_index: u32, type_index: u32, options: O) -> &mut Self
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.bytes.push(0x00);
+        self.bytes.push(0x00);
+        core_func_index.encode(&mut self.bytes);
+        self.encode_options(options);
+        type_index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Define a function that will lower a canonical ABI function to a core WebAssembly function.
+    pub fn lower<O>(&mut self, func_index: u32, options: O) -> &mut Self
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.bytes.push(0x01);
+        self.bytes.push(0x00);
+        func_index.encode(&mut self.bytes);
+        self.encode_options(options);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function which will create an owned handle to the resource
+    /// specified by `ty_index`.
+    pub fn resource_new(&mut self, ty_index: u32) -> &mut Self {
+        self.bytes.push(0x02);
+        ty_index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function which will drop the specified type of handle.
+    pub fn resource_drop(&mut self, ty_index: u32) -> &mut Self {
+        self.bytes.push(0x03);
+        ty_index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function which will drop the specified type of handle.
+    pub fn resource_drop_async(&mut self, ty_index: u32) -> &mut Self {
+        self.bytes.push(0x07);
+        ty_index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function which will return the representation of the specified
+    /// resource type.
+    pub fn resource_rep(&mut self, ty_index: u32) -> &mut Self {
+        self.bytes.push(0x04);
+        ty_index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function which will spawn a new thread by invoking a shared
+    /// function of type `ty_index`.
+    pub fn thread_spawn_ref(&mut self, ty_index: u32) -> &mut Self {
+        self.bytes.push(0x40);
+        ty_index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function which will spawn a new thread by invoking a shared
+    /// function indirectly through a `funcref` table.
+    pub fn thread_spawn_indirect(&mut self, ty_index: u32, table_index: u32) -> &mut Self {
+        self.bytes.push(0x41);
+        ty_index.encode(&mut self.bytes);
+        table_index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function which will return the number of threads that can be
+    /// expected to execute concurrently.
+    pub fn thread_available_parallelism(&mut self) -> &mut Self {
+        self.bytes.push(0x42);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function which tells the host to increment the backpressure
+    /// counter.
+    pub fn backpressure_inc(&mut self) -> &mut Self {
+        self.bytes.push(0x24);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function which tells the host to decrement the backpressure
+    /// counter.
+    pub fn backpressure_dec(&mut self) -> &mut Self {
+        self.bytes.push(0x25);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function which returns a result to the caller of a lifted
+    /// export function.  This allows the callee to continue executing after
+    /// returning a result.
+    pub fn task_return<O>(&mut self, ty: Option<ComponentValType>, options: O) -> &mut Self
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.bytes.push(0x09);
+        crate::encode_resultlist(&mut self.bytes, ty);
+        self.encode_options(options);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to acknowledge cancellation of the current task.
+    pub fn task_cancel(&mut self) -> &mut Self {
+        self.bytes.push(0x05);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a new `context.get` intrinsic of the ith slot.
+    pub fn context_get(&mut self, i: u32) -> &mut Self {
+        self.bytes.push(0x0a);
+        self.bytes.push(0x7f);
+        i.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a new `context.set` intrinsic of the ith slot.
+    pub fn context_set(&mut self, i: u32) -> &mut Self {
+        self.bytes.push(0x0b);
+        self.bytes.push(0x7f);
+        i.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function which yields control to the host so that other tasks
+    /// are able to make progress, if any.
+    ///
+    /// If `cancellable` is true, the caller instance may be reentered.
+    pub fn thread_yield(&mut self, cancellable: bool) -> &mut Self {
+        self.bytes.push(0x0c);
+        self.bytes.push(if cancellable { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to drop a specified task which has completed.
+    pub fn subtask_drop(&mut self) -> &mut Self {
+        self.bytes.push(0x0d);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to cancel an in-progress task.
+    pub fn subtask_cancel(&mut self, async_: bool) -> &mut Self {
+        self.bytes.push(0x06);
+        self.bytes.push(if async_ { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to create a new `stream` handle of the specified
+    /// type.
+    pub fn stream_new(&mut self, ty: u32) -> &mut Self {
+        self.bytes.push(0x0e);
+        ty.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to read from a `stream` of the specified type.
+    pub fn stream_read<O>(&mut self, ty: u32, options: O) -> &mut Self
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.bytes.push(0x0f);
+        ty.encode(&mut self.bytes);
+        self.encode_options(options);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to write to a `stream` of the specified type.
+    pub fn stream_write<O>(&mut self, ty: u32, options: O) -> &mut Self
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.bytes.push(0x10);
+        ty.encode(&mut self.bytes);
+        self.encode_options(options);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to cancel an in-progress read from a `stream` of the
+    /// specified type.
+    pub fn stream_cancel_read(&mut self, ty: u32, async_: bool) -> &mut Self {
+        self.bytes.push(0x11);
+        ty.encode(&mut self.bytes);
+        self.bytes.push(if async_ { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to cancel an in-progress write to a `stream` of the
+    /// specified type.
+    pub fn stream_cancel_write(&mut self, ty: u32, async_: bool) -> &mut Self {
+        self.bytes.push(0x12);
+        ty.encode(&mut self.bytes);
+        self.bytes.push(if async_ { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to drop the readable end of a `stream` of the
+    /// specified type.
+    pub fn stream_drop_readable(&mut self, ty: u32) -> &mut Self {
+        self.bytes.push(0x13);
+        ty.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to drop the writable end of a `stream` of the
+    /// specified type.
+    pub fn stream_drop_writable(&mut self, ty: u32) -> &mut Self {
+        self.bytes.push(0x14);
+        ty.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to create a new `future` handle of the specified
+    /// type.
+    pub fn future_new(&mut self, ty: u32) -> &mut Self {
+        self.bytes.push(0x15);
+        ty.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to read from a `future` of the specified type.
+    pub fn future_read<O>(&mut self, ty: u32, options: O) -> &mut Self
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.bytes.push(0x16);
+        ty.encode(&mut self.bytes);
+        self.encode_options(options);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to write to a `future` of the specified type.
+    pub fn future_write<O>(&mut self, ty: u32, options: O) -> &mut Self
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.bytes.push(0x17);
+        ty.encode(&mut self.bytes);
+        self.encode_options(options);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to cancel an in-progress read from a `future` of the
+    /// specified type.
+    pub fn future_cancel_read(&mut self, ty: u32, async_: bool) -> &mut Self {
+        self.bytes.push(0x18);
+        ty.encode(&mut self.bytes);
+        self.bytes.push(if async_ { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to cancel an in-progress write to a `future` of the
+    /// specified type.
+    pub fn future_cancel_write(&mut self, ty: u32, async_: bool) -> &mut Self {
+        self.bytes.push(0x19);
+        ty.encode(&mut self.bytes);
+        self.bytes.push(if async_ { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to drop the readable end of a `future` of the
+    /// specified type.
+    pub fn future_drop_readable(&mut self, ty: u32) -> &mut Self {
+        self.bytes.push(0x1a);
+        ty.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to drop the writable end of a `future` of the
+    /// specified type.
+    pub fn future_drop_writable(&mut self, ty: u32) -> &mut Self {
+        self.bytes.push(0x1b);
+        ty.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to create a new `error-context` with a specified
+    /// debug message.
+    pub fn error_context_new<O>(&mut self, options: O) -> &mut Self
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.bytes.push(0x1c);
+        self.encode_options(options);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to get the debug message for a specified
+    /// `error-context`.
+    ///
+    /// Note that the debug message might not necessarily match what was passed
+    /// to `error-context.new`.
+    pub fn error_context_debug_message<O>(&mut self, options: O) -> &mut Self
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        self.bytes.push(0x1d);
+        self.encode_options(options);
+        self.num_added += 1;
+        self
+    }
+
+    /// Defines a function to drop a specified `error-context`.
+    pub fn error_context_drop(&mut self) -> &mut Self {
+        self.bytes.push(0x1e);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `waitable-set.new` intrinsic, used to create a
+    /// `waitable-set` pseudo-resource.
+    pub fn waitable_set_new(&mut self) -> &mut Self {
+        self.bytes.push(0x1f);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `waitable-set.wait` intrinsic, used to block on a
+    /// `waitable-set`.
+    pub fn waitable_set_wait(&mut self, async_: bool, memory: u32) -> &mut Self {
+        self.bytes.push(0x20);
+        self.bytes.push(if async_ { 1 } else { 0 });
+        memory.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `waitable-set.wait` intrinsic, used to check, without
+    /// blocking, if anything in a `waitable-set` is ready.
+    pub fn waitable_set_poll(&mut self, async_: bool, memory: u32) -> &mut Self {
+        self.bytes.push(0x21);
+        self.bytes.push(if async_ { 1 } else { 0 });
+        memory.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `waitable-set.drop` intrinsic, used to dispose a
+    /// `waitable-set` pseudo-resource.
+    pub fn waitable_set_drop(&mut self) -> &mut Self {
+        self.bytes.push(0x22);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `waitable.join` intrinsic, used to add an item to a
+    /// `waitable-set`.
+    pub fn waitable_join(&mut self) -> &mut Self {
+        self.bytes.push(0x23);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `thread.index` intrinsic, used to get the index of the
+    /// current thread.
+    pub fn thread_index(&mut self) -> &mut Self {
+        self.bytes.push(0x26);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `thread.new-indirect` intrinsic, used to create a new
+    /// thread by invoking a function indirectly through a `funcref` table.
+    pub fn thread_new_indirect(&mut self, ty_index: u32, table_index: u32) -> &mut Self {
+        self.bytes.push(0x27);
+        ty_index.encode(&mut self.bytes);
+        table_index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `thread.switch-to` intrinsic, used to switch execution to
+    /// another thread.
+    pub fn thread_switch_to(&mut self, cancellable: bool) -> &mut Self {
+        self.bytes.push(0x28);
+        self.bytes.push(if cancellable { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `thread.suspend` intrinsic, used to suspend execution of
+    /// the current thread.
+    pub fn thread_suspend(&mut self, cancellable: bool) -> &mut Self {
+        self.bytes.push(0x29);
+        self.bytes.push(if cancellable { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `thread.resume-later` intrinsic, used to resume execution
+    /// of the given thread.
+    pub fn thread_resume_later(&mut self) -> &mut Self {
+        self.bytes.push(0x2a);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `thread.yield-to` intrinsic, used to yield execution to
+    /// a given thread.
+    pub fn thread_yield_to(&mut self, cancellable: bool) -> &mut Self {
+        self.bytes.push(0x2b);
+        self.bytes.push(if cancellable { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
+    fn encode_options<O>(&mut self, options: O) -> &mut Self
+    where
+        O: IntoIterator<Item = CanonicalOption>,
+        O::IntoIter: ExactSizeIterator,
+    {
+        let options = options.into_iter();
+        options.len().encode(&mut self.bytes);
+        for option in options {
+            option.encode(&mut self.bytes);
+        }
+        self
+    }
+}
+
+impl Encode for CanonicalFunctionSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl ComponentSection for CanonicalFunctionSection {
+    fn id(&self) -> u8 {
+        ComponentSectionId::CanonicalFunction.into()
+    }
+}

vendor/wasm-encoder/src/component/components.rs

@@ -0,0 +1,30 @@
+use crate::{Component, ComponentSection, ComponentSectionId, Encode};
+use alloc::vec::Vec;
+
+/// An encoder for the component section of WebAssembly components.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{Component, NestedComponentSection};
+///
+/// let mut nested = Component::new();
+/// let mut component = Component::new();
+/// component.section(&NestedComponentSection(&nested));
+///
+/// let bytes = component.finish();
+/// ```
+#[derive(Clone, Debug)]
+pub struct NestedComponentSection<'a>(pub &'a Component);
+
+impl Encode for NestedComponentSection<'_> {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.0.bytes.encode(sink);
+    }
+}
+
+impl ComponentSection for NestedComponentSection<'_> {
+    fn id(&self) -> u8 {
+        ComponentSectionId::Component.into()
+    }
+}

vendor/wasm-encoder/src/component/exports.rs

@@ -0,0 +1,130 @@
+use super::{
+    COMPONENT_SORT, CORE_MODULE_SORT, CORE_SORT, FUNCTION_SORT, INSTANCE_SORT, TYPE_SORT,
+    VALUE_SORT,
+};
+use crate::{ComponentSection, ComponentSectionId, ComponentTypeRef, Encode, encode_section};
+use alloc::vec::Vec;
+
+/// Represents the kind of an export from a WebAssembly component.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum ComponentExportKind {
+    /// The export is a core module.
+    Module,
+    /// The export is a function.
+    Func,
+    /// The export is a value.
+    Value,
+    /// The export is a type.
+    Type,
+    /// The export is an instance.
+    Instance,
+    /// The export is a component.
+    Component,
+}
+
+impl Encode for ComponentExportKind {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            Self::Module => {
+                sink.push(CORE_SORT);
+                sink.push(CORE_MODULE_SORT);
+            }
+            Self::Func => {
+                sink.push(FUNCTION_SORT);
+            }
+            Self::Value => {
+                sink.push(VALUE_SORT);
+            }
+            Self::Type => {
+                sink.push(TYPE_SORT);
+            }
+            Self::Instance => {
+                sink.push(INSTANCE_SORT);
+            }
+            Self::Component => {
+                sink.push(COMPONENT_SORT);
+            }
+        }
+    }
+}
+
+/// An encoder for the export section of WebAssembly component.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{Component, ComponentExportSection, ComponentExportKind};
+///
+/// // This exports a function named "foo"
+/// let mut exports = ComponentExportSection::new();
+/// exports.export("foo", ComponentExportKind::Func, 0, None);
+///
+/// let mut component = Component::new();
+/// component.section(&exports);
+///
+/// let bytes = component.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct ComponentExportSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl ComponentExportSection {
+    /// Create a new component export section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of exports in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define an export in the export section.
+    pub fn export(
+        &mut self,
+        name: &str,
+        kind: ComponentExportKind,
+        index: u32,
+        ty: Option<ComponentTypeRef>,
+    ) -> &mut Self {
+        crate::encode_component_export_name(&mut self.bytes, name);
+        kind.encode(&mut self.bytes);
+        index.encode(&mut self.bytes);
+        match ty {
+            Some(ty) => {
+                self.bytes.push(0x01);
+                ty.encode(&mut self.bytes);
+            }
+            None => {
+                self.bytes.push(0x00);
+            }
+        }
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for ComponentExportSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl ComponentSection for ComponentExportSection {
+    fn id(&self) -> u8 {
+        ComponentSectionId::Export.into()
+    }
+}
+
+/// For more information on this see `encode_component_import_name`.
+pub(crate) fn encode_component_export_name(bytes: &mut Vec<u8>, name: &str) {
+    bytes.push(0x00);
+    name.encode(bytes);
+}

vendor/wasm-encoder/src/component/imports.rs

@@ -0,0 +1,170 @@
+use crate::{
+    ComponentExportKind, ComponentSection, ComponentSectionId, ComponentValType, Encode,
+    encode_section,
+};
+use alloc::vec::Vec;
+
+/// Represents the possible type bounds for type references.
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
+pub enum TypeBounds {
+    /// The type is bounded by equality to the type index specified.
+    Eq(u32),
+    /// This type is a fresh resource type,
+    SubResource,
+}
+
+impl Encode for TypeBounds {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            Self::Eq(i) => {
+                sink.push(0x00);
+                i.encode(sink);
+            }
+            Self::SubResource => sink.push(0x01),
+        }
+    }
+}
+
+/// Represents a reference to a type.
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
+pub enum ComponentTypeRef {
+    /// The reference is to a core module type.
+    ///
+    /// The index is expected to be core type index to a core module type.
+    Module(u32),
+    /// The reference is to a function type.
+    ///
+    /// The index is expected to be a type index to a function type.
+    Func(u32),
+    /// The reference is to a value type.
+    Value(ComponentValType),
+    /// The reference is to a bounded type.
+    Type(TypeBounds),
+    /// The reference is to an instance type.
+    ///
+    /// The index is expected to be a type index to an instance type.
+    Instance(u32),
+    /// The reference is to a component type.
+    ///
+    /// The index is expected to be a type index to a component type.
+    Component(u32),
+}
+
+impl ComponentTypeRef {
+    /// Gets the export kind of the reference.
+    pub fn kind(&self) -> ComponentExportKind {
+        match self {
+            Self::Module(_) => ComponentExportKind::Module,
+            Self::Func(_) => ComponentExportKind::Func,
+            Self::Value(_) => ComponentExportKind::Value,
+            Self::Type(..) => ComponentExportKind::Type,
+            Self::Instance(_) => ComponentExportKind::Instance,
+            Self::Component(_) => ComponentExportKind::Component,
+        }
+    }
+}
+
+impl Encode for ComponentTypeRef {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.kind().encode(sink);
+
+        match self {
+            Self::Module(idx) | Self::Func(idx) | Self::Instance(idx) | Self::Component(idx) => {
+                idx.encode(sink);
+            }
+            Self::Value(ty) => ty.encode(sink),
+            Self::Type(bounds) => bounds.encode(sink),
+        }
+    }
+}
+
+/// An encoder for the import section of WebAssembly components.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{Component, ComponentTypeSection, PrimitiveValType, ComponentImportSection, ComponentTypeRef};
+///
+/// let mut types = ComponentTypeSection::new();
+///
+/// // Define a function type of `[string, string] -> string`.
+/// types
+///   .function()
+///   .params(
+///     [
+///       ("a", PrimitiveValType::String),
+///       ("b", PrimitiveValType::String)
+///     ]
+///   )
+///   .result(Some(PrimitiveValType::String.into()));
+///
+/// // This imports a function named `f` with the type defined above
+/// let mut imports = ComponentImportSection::new();
+/// imports.import("f", ComponentTypeRef::Func(0));
+///
+/// let mut component = Component::new();
+/// component.section(&types);
+/// component.section(&imports);
+///
+/// let bytes = component.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct ComponentImportSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl ComponentImportSection {
+    /// Create a new component import section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of imports in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define an import in the component import section.
+    pub fn import(&mut self, name: &str, ty: ComponentTypeRef) -> &mut Self {
+        encode_component_import_name(&mut self.bytes, name);
+        ty.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for ComponentImportSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl ComponentSection for ComponentImportSection {
+    fn id(&self) -> u8 {
+        ComponentSectionId::Import.into()
+    }
+}
+
+/// Prior to WebAssembly/component-model#263 import and export names were
+/// discriminated with a leading byte indicating what kind of import they are.
+/// After that PR though names are always prefixed with a 0x00 byte.
+///
+/// On 2023-10-28 in bytecodealliance/wasm-tools#1262 was landed to start
+/// transitioning to "always lead with 0x00". That updated the validator/parser
+/// to accept either 0x00 or 0x01 but the encoder wasn't updated at the time.
+///
+/// On 2024-09-03 in bytecodealliance/wasm-tools#TODO this encoder was updated
+/// to always emit 0x00 as a leading byte.
+///
+/// This function corresponds with the `importname'` production in the
+/// specification.
+pub(crate) fn encode_component_import_name(bytes: &mut Vec<u8>, name: &str) {
+    bytes.push(0x00);
+    name.encode(bytes);
+}

vendor/wasm-encoder/src/component/instances.rs

@@ -0,0 +1,200 @@
+use super::CORE_INSTANCE_SORT;
+use crate::{
+    ComponentExportKind, ComponentSection, ComponentSectionId, Encode, ExportKind, encode_section,
+};
+use alloc::vec::Vec;
+
+/// Represents an argument to a module instantiation.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum ModuleArg {
+    /// The argument is an instance.
+    Instance(u32),
+}
+
+impl Encode for ModuleArg {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        let (sort, idx) = match self {
+            Self::Instance(idx) => (CORE_INSTANCE_SORT, *idx),
+        };
+        sink.push(sort);
+        idx.encode(sink);
+    }
+}
+
+/// An encoder for the core instance section of WebAssembly components.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{Component, InstanceSection, ExportKind, ModuleArg};
+///
+/// let mut instances = InstanceSection::new();
+/// instances.export_items([("foo", ExportKind::Func, 0)]);
+/// instances.instantiate(1, [("foo", ModuleArg::Instance(0))]);
+///
+/// let mut component = Component::new();
+/// component.section(&instances);
+///
+/// let bytes = component.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct InstanceSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl InstanceSection {
+    /// Create a new core instance section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of instances in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define an instance by instantiating a core module.
+    pub fn instantiate<A, S>(&mut self, module_index: u32, args: A) -> &mut Self
+    where
+        A: IntoIterator<Item = (S, ModuleArg)>,
+        A::IntoIter: ExactSizeIterator,
+        S: AsRef<str>,
+    {
+        let args = args.into_iter();
+        self.bytes.push(0x00);
+        module_index.encode(&mut self.bytes);
+        args.len().encode(&mut self.bytes);
+        for (name, arg) in args {
+            name.as_ref().encode(&mut self.bytes);
+            arg.encode(&mut self.bytes);
+        }
+        self.num_added += 1;
+        self
+    }
+
+    /// Define an instance by exporting core WebAssembly items.
+    pub fn export_items<E, S>(&mut self, exports: E) -> &mut Self
+    where
+        E: IntoIterator<Item = (S, ExportKind, u32)>,
+        E::IntoIter: ExactSizeIterator,
+        S: AsRef<str>,
+    {
+        let exports = exports.into_iter();
+        self.bytes.push(0x01);
+        exports.len().encode(&mut self.bytes);
+        for (name, kind, index) in exports {
+            name.as_ref().encode(&mut self.bytes);
+            kind.encode(&mut self.bytes);
+            index.encode(&mut self.bytes);
+        }
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for InstanceSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl ComponentSection for InstanceSection {
+    fn id(&self) -> u8 {
+        ComponentSectionId::CoreInstance.into()
+    }
+}
+
+/// An encoder for the instance section of WebAssembly components.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{Component, ComponentInstanceSection, ComponentExportKind};
+///
+/// let mut instances = ComponentInstanceSection::new();
+/// instances.export_items([("foo", ComponentExportKind::Func, 0)]);
+/// instances.instantiate(1, [("foo", ComponentExportKind::Instance, 0)]);
+///
+/// let mut component = Component::new();
+/// component.section(&instances);
+///
+/// let bytes = component.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct ComponentInstanceSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl ComponentInstanceSection {
+    /// Create a new instance section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of instances in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define an instance by instantiating a component.
+    pub fn instantiate<A, S>(&mut self, component_index: u32, args: A) -> &mut Self
+    where
+        A: IntoIterator<Item = (S, ComponentExportKind, u32)>,
+        A::IntoIter: ExactSizeIterator,
+        S: AsRef<str>,
+    {
+        let args = args.into_iter();
+        self.bytes.push(0x00);
+        component_index.encode(&mut self.bytes);
+        args.len().encode(&mut self.bytes);
+        for (name, kind, index) in args {
+            name.as_ref().encode(&mut self.bytes);
+            kind.encode(&mut self.bytes);
+            index.encode(&mut self.bytes);
+        }
+        self.num_added += 1;
+        self
+    }
+
+    /// Define an instance by exporting items.
+    pub fn export_items<'a, E>(&mut self, exports: E) -> &mut Self
+    where
+        E: IntoIterator<Item = (&'a str, ComponentExportKind, u32)>,
+        E::IntoIter: ExactSizeIterator,
+    {
+        let exports = exports.into_iter();
+        self.bytes.push(0x01);
+        exports.len().encode(&mut self.bytes);
+        for (name, kind, index) in exports {
+            crate::encode_component_export_name(&mut self.bytes, name);
+            kind.encode(&mut self.bytes);
+            index.encode(&mut self.bytes);
+        }
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for ComponentInstanceSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl ComponentSection for ComponentInstanceSection {
+    fn id(&self) -> u8 {
+        ComponentSectionId::Instance.into()
+    }
+}

vendor/wasm-encoder/src/component/modules.rs

@@ -0,0 +1,30 @@
+use crate::{ComponentSection, ComponentSectionId, Encode, Module};
+use alloc::vec::Vec;
+
+/// An encoder for the module section of WebAssembly components.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{Module, Component, ModuleSection};
+///
+/// let mut module = Module::new();
+/// let mut component = Component::new();
+/// component.section(&ModuleSection(&module));
+///
+/// let bytes = component.finish();
+/// ```
+#[derive(Clone, Debug)]
+pub struct ModuleSection<'a>(pub &'a Module);
+
+impl Encode for ModuleSection<'_> {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.0.bytes.encode(sink);
+    }
+}
+
+impl ComponentSection for ModuleSection<'_> {
+    fn id(&self) -> u8 {
+        ComponentSectionId::CoreModule.into()
+    }
+}

vendor/wasm-encoder/src/component/names.rs

@@ -0,0 +1,162 @@
+use alloc::borrow::Cow;
+use alloc::vec::Vec;
+
+use super::*;
+use crate::{ExportKind, NameMap, SectionId, encoding_size};
+
+/// Encoding for the `component-name` custom section which assigns
+/// human-readable names to items within a component.
+#[derive(Clone, Debug, Default)]
+pub struct ComponentNameSection {
+    bytes: Vec<u8>,
+}
+
+enum Subsection {
+    Component,
+    Decls,
+}
+
+impl ComponentNameSection {
+    /// Creates a new blank `name` custom section.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Appends a component name subsection to this section.
+    ///
+    /// This will indicate that the name of the entire component should be the
+    /// `name` specified. Note that this should be encoded first before other
+    /// subsections.
+    pub fn component(&mut self, name: &str) {
+        let len = encoding_size(u32::try_from(name.len()).unwrap());
+        self.subsection_header(Subsection::Component, len + name.len());
+        name.encode(&mut self.bytes);
+    }
+
+    /// Appends a decls name subsection to name core functions within the
+    /// component.
+    pub fn core_funcs(&mut self, names: &NameMap) {
+        self.core_decls(ExportKind::Func as u8, names)
+    }
+
+    /// Appends a decls name subsection to name core tables within the
+    /// component.
+    pub fn core_tables(&mut self, names: &NameMap) {
+        self.core_decls(ExportKind::Table as u8, names)
+    }
+
+    /// Appends a decls name subsection to name core memories within the
+    /// component.
+    pub fn core_memories(&mut self, names: &NameMap) {
+        self.core_decls(ExportKind::Memory as u8, names)
+    }
+
+    /// Appends a decls name subsection to name core globals within the
+    /// component.
+    pub fn core_globals(&mut self, names: &NameMap) {
+        self.core_decls(ExportKind::Global as u8, names)
+    }
+
+    /// Appends a decls name subsection to name core tags within the
+    /// component.
+    pub fn core_tags(&mut self, names: &NameMap) {
+        self.core_decls(ExportKind::Tag as u8, names)
+    }
+
+    /// Appends a decls name subsection to name core types within the
+    /// component.
+    pub fn core_types(&mut self, names: &NameMap) {
+        self.core_decls(CORE_TYPE_SORT, names)
+    }
+
+    /// Appends a decls name subsection to name core modules within the
+    /// component.
+    pub fn core_modules(&mut self, names: &NameMap) {
+        self.core_decls(CORE_MODULE_SORT, names)
+    }
+
+    /// Appends a decls name subsection to name core instances within the
+    /// component.
+    pub fn core_instances(&mut self, names: &NameMap) {
+        self.core_decls(CORE_INSTANCE_SORT, names)
+    }
+
+    /// Appends a decls name subsection to name component functions within the
+    /// component.
+    pub fn funcs(&mut self, names: &NameMap) {
+        self.component_decls(FUNCTION_SORT, names)
+    }
+
+    /// Appends a decls name subsection to name component values within the
+    /// component.
+    pub fn values(&mut self, names: &NameMap) {
+        self.component_decls(VALUE_SORT, names)
+    }
+
+    /// Appends a decls name subsection to name component type within the
+    /// component.
+    pub fn types(&mut self, names: &NameMap) {
+        self.component_decls(TYPE_SORT, names)
+    }
+
+    /// Appends a decls name subsection to name components within the
+    /// component.
+    pub fn components(&mut self, names: &NameMap) {
+        self.component_decls(COMPONENT_SORT, names)
+    }
+
+    /// Appends a decls name subsection to name component instances within the
+    /// component.
+    pub fn instances(&mut self, names: &NameMap) {
+        self.component_decls(INSTANCE_SORT, names)
+    }
+
+    /// Appends a raw subsection with the given id and data.
+    pub fn raw(&mut self, id: u8, data: &[u8]) {
+        self.bytes.push(id);
+        data.encode(&mut self.bytes);
+    }
+
+    fn component_decls(&mut self, kind: u8, names: &NameMap) {
+        self.subsection_header(Subsection::Decls, 1 + names.size());
+        self.bytes.push(kind);
+        names.encode(&mut self.bytes);
+    }
+
+    fn core_decls(&mut self, kind: u8, names: &NameMap) {
+        self.subsection_header(Subsection::Decls, 2 + names.size());
+        self.bytes.push(CORE_SORT);
+        self.bytes.push(kind);
+        names.encode(&mut self.bytes);
+    }
+
+    fn subsection_header(&mut self, id: Subsection, len: usize) {
+        self.bytes.push(id as u8);
+        len.encode(&mut self.bytes);
+    }
+
+    /// Returns whether this section is empty, or nothing has been encoded.
+    pub fn is_empty(&self) -> bool {
+        self.bytes.is_empty()
+    }
+
+    /// View the encoded section as a CustomSection.
+    pub fn as_custom<'a>(&'a self) -> CustomSection<'a> {
+        CustomSection {
+            name: "component-name".into(),
+            data: Cow::Borrowed(&self.bytes),
+        }
+    }
+}
+
+impl Encode for ComponentNameSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.as_custom().encode(sink);
+    }
+}
+
+impl ComponentSection for ComponentNameSection {
+    fn id(&self) -> u8 {
+        SectionId::Custom.into()
+    }
+}

vendor/wasm-encoder/src/component/start.rs

@@ -0,0 +1,53 @@
+use crate::{ComponentSection, ComponentSectionId, Encode};
+use alloc::vec::Vec;
+
+/// An encoder for the start section of WebAssembly components.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{Component, ComponentStartSection};
+///
+/// let start = ComponentStartSection { function_index: 0, args: [0, 1], results: 1 };
+///
+/// let mut component = Component::new();
+/// component.section(&start);
+///
+/// let bytes = component.finish();
+/// ```
+#[derive(Clone, Debug)]
+pub struct ComponentStartSection<A> {
+    /// The index to the start function.
+    pub function_index: u32,
+    /// The arguments to pass to the start function.
+    ///
+    /// An argument is an index to a value.
+    pub args: A,
+    /// The number of expected results for the start function.
+    ///
+    /// This should match the number of results for the type of
+    /// the function referenced by `function_index`.
+    pub results: u32,
+}
+
+impl<A> Encode for ComponentStartSection<A>
+where
+    A: AsRef<[u32]>,
+{
+    fn encode(&self, sink: &mut Vec<u8>) {
+        let mut bytes = Vec::new();
+        self.function_index.encode(&mut bytes);
+        self.args.as_ref().encode(&mut bytes);
+        self.results.encode(&mut bytes);
+        bytes.encode(sink);
+    }
+}
+
+impl<A> ComponentSection for ComponentStartSection<A>
+where
+    A: AsRef<[u32]>,
+{
+    fn id(&self) -> u8 {
+        ComponentSectionId::Start.into()
+    }
+}

vendor/wasm-encoder/src/component/types.rs

@@ -0,0 +1,816 @@
+use super::CORE_TYPE_SORT;
+use crate::{
+    Alias, ComponentExportKind, ComponentOuterAliasKind, ComponentSection, ComponentSectionId,
+    ComponentTypeRef, CoreTypeEncoder, Encode, EntityType, ValType, encode_section,
+};
+use alloc::vec::Vec;
+
+/// Represents the type of a core module.
+#[derive(Debug, Clone, Default)]
+pub struct ModuleType {
+    bytes: Vec<u8>,
+    num_added: u32,
+    types_added: u32,
+}
+
+impl ModuleType {
+    /// Creates a new core module type.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Defines an import in this module type.
+    pub fn import(&mut self, module: &str, name: &str, ty: EntityType) -> &mut Self {
+        self.bytes.push(0x00);
+        module.encode(&mut self.bytes);
+        name.encode(&mut self.bytes);
+        ty.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Define a type in this module type.
+    ///
+    /// The returned encoder must be used before adding another definition.
+    #[must_use = "the encoder must be used to encode the type"]
+    pub fn ty(&mut self) -> CoreTypeEncoder<'_> {
+        self.bytes.push(0x01);
+        self.num_added += 1;
+        self.types_added += 1;
+        CoreTypeEncoder {
+            push_prefix_if_component_core_type: false,
+            bytes: &mut self.bytes,
+        }
+    }
+
+    /// Defines an outer core type alias in this module type.
+    pub fn alias_outer_core_type(&mut self, count: u32, index: u32) -> &mut Self {
+        self.bytes.push(0x02);
+        self.bytes.push(CORE_TYPE_SORT);
+        self.bytes.push(0x01); // outer
+        count.encode(&mut self.bytes);
+        index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self.types_added += 1;
+        self
+    }
+
+    /// Defines an export in this module type.
+    pub fn export(&mut self, name: &str, ty: EntityType) -> &mut Self {
+        self.bytes.push(0x03);
+        name.encode(&mut self.bytes);
+        ty.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Gets the number of types that have been added to this module type.
+    pub fn type_count(&self) -> u32 {
+        self.types_added
+    }
+}
+
+impl Encode for ModuleType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        sink.push(0x50);
+        self.num_added.encode(sink);
+        sink.extend(&self.bytes);
+    }
+}
+
+/// Used to encode core types.
+#[derive(Debug)]
+pub struct ComponentCoreTypeEncoder<'a>(pub(crate) &'a mut Vec<u8>);
+
+impl<'a> ComponentCoreTypeEncoder<'a> {
+    /// Define a module type.
+    pub fn module(self, ty: &ModuleType) {
+        ty.encode(self.0);
+    }
+
+    /// Define any core type other than a module type.
+    #[must_use = "the encoder must be used to encode the type"]
+    pub fn core(self) -> CoreTypeEncoder<'a> {
+        CoreTypeEncoder {
+            bytes: self.0,
+            push_prefix_if_component_core_type: true,
+        }
+    }
+}
+
+/// An encoder for the core type section of WebAssembly components.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{Component, CoreTypeSection, ModuleType};
+///
+/// let mut types = CoreTypeSection::new();
+///
+/// types.ty().module(&ModuleType::new());
+///
+/// let mut component = Component::new();
+/// component.section(&types);
+///
+/// let bytes = component.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct CoreTypeSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl CoreTypeSection {
+    /// Create a new core type section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of types in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Encode a type into this section.
+    ///
+    /// The returned encoder must be finished before adding another type.
+    #[must_use = "the encoder must be used to encode the type"]
+    pub fn ty(&mut self) -> ComponentCoreTypeEncoder<'_> {
+        self.num_added += 1;
+        ComponentCoreTypeEncoder(&mut self.bytes)
+    }
+}
+
+impl Encode for CoreTypeSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl ComponentSection for CoreTypeSection {
+    fn id(&self) -> u8 {
+        ComponentSectionId::CoreType.into()
+    }
+}
+
+/// Represents a component type.
+#[derive(Debug, Clone, Default)]
+pub struct ComponentType {
+    bytes: Vec<u8>,
+    num_added: u32,
+    core_types_added: u32,
+    types_added: u32,
+    instances_added: u32,
+}
+
+impl ComponentType {
+    /// Creates a new component type.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Define a core type in this component type.
+    ///
+    /// The returned encoder must be used before adding another definition.
+    #[must_use = "the encoder must be used to encode the type"]
+    pub fn core_type(&mut self) -> ComponentCoreTypeEncoder<'_> {
+        self.bytes.push(0x00);
+        self.num_added += 1;
+        self.core_types_added += 1;
+        ComponentCoreTypeEncoder(&mut self.bytes)
+    }
+
+    /// Define a type in this component type.
+    ///
+    /// The returned encoder must be used before adding another definition.
+    #[must_use = "the encoder must be used to encode the type"]
+    pub fn ty(&mut self) -> ComponentTypeEncoder<'_> {
+        self.bytes.push(0x01);
+        self.num_added += 1;
+        self.types_added += 1;
+        ComponentTypeEncoder(&mut self.bytes)
+    }
+
+    /// Defines an alias for an exported item of a prior instance or an
+    /// outer type.
+    pub fn alias(&mut self, alias: Alias<'_>) -> &mut Self {
+        self.bytes.push(0x02);
+        alias.encode(&mut self.bytes);
+        self.num_added += 1;
+        match &alias {
+            Alias::InstanceExport {
+                kind: ComponentExportKind::Type,
+                ..
+            }
+            | Alias::Outer {
+                kind: ComponentOuterAliasKind::Type,
+                ..
+            } => self.types_added += 1,
+            Alias::Outer {
+                kind: ComponentOuterAliasKind::CoreType,
+                ..
+            } => self.core_types_added += 1,
+            Alias::InstanceExport {
+                kind: ComponentExportKind::Instance,
+                ..
+            } => self.instances_added += 1,
+            _ => {}
+        }
+        self
+    }
+
+    /// Defines an import in this component type.
+    pub fn import(&mut self, name: &str, ty: ComponentTypeRef) -> &mut Self {
+        self.bytes.push(0x03);
+        crate::encode_component_import_name(&mut self.bytes, name);
+        ty.encode(&mut self.bytes);
+        self.num_added += 1;
+        match ty {
+            ComponentTypeRef::Type(..) => self.types_added += 1,
+            ComponentTypeRef::Instance(..) => self.instances_added += 1,
+            _ => {}
+        }
+        self
+    }
+
+    /// Defines an export in this component type.
+    pub fn export(&mut self, name: &str, ty: ComponentTypeRef) -> &mut Self {
+        self.bytes.push(0x04);
+        crate::encode_component_export_name(&mut self.bytes, name);
+        ty.encode(&mut self.bytes);
+        self.num_added += 1;
+        match ty {
+            ComponentTypeRef::Type(..) => self.types_added += 1,
+            ComponentTypeRef::Instance(..) => self.instances_added += 1,
+            _ => {}
+        }
+        self
+    }
+
+    /// Gets the number of core types that have been added to this component type.
+    pub fn core_type_count(&self) -> u32 {
+        self.core_types_added
+    }
+
+    /// Gets the number of types that have been added or aliased in this component type.
+    pub fn type_count(&self) -> u32 {
+        self.types_added
+    }
+
+    /// Gets the number of instances that have been defined in this component
+    /// type through imports, exports, or aliases.
+    pub fn instance_count(&self) -> u32 {
+        self.instances_added
+    }
+}
+
+impl Encode for ComponentType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        sink.push(0x41);
+        self.num_added.encode(sink);
+        sink.extend(&self.bytes);
+    }
+}
+
+/// Represents an instance type.
+#[derive(Debug, Clone, Default)]
+pub struct InstanceType(ComponentType);
+
+impl InstanceType {
+    /// Creates a new instance type.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Define a core type in this instance type.
+    ///
+    /// The returned encoder must be used before adding another definition.
+    #[must_use = "the encoder must be used to encode the type"]
+    pub fn core_type(&mut self) -> ComponentCoreTypeEncoder<'_> {
+        self.0.core_type()
+    }
+
+    /// Define a type in this instance type.
+    ///
+    /// The returned encoder must be used before adding another definition.
+    #[must_use = "the encoder must be used to encode the type"]
+    pub fn ty(&mut self) -> ComponentTypeEncoder<'_> {
+        self.0.ty()
+    }
+
+    /// Defines an outer core type alias in this component type.
+    pub fn alias(&mut self, alias: Alias<'_>) -> &mut Self {
+        self.0.alias(alias);
+        self
+    }
+
+    /// Defines an export in this instance type.
+    pub fn export(&mut self, name: &str, ty: ComponentTypeRef) -> &mut Self {
+        self.0.export(name, ty);
+        self
+    }
+
+    /// Gets the number of core types that have been added to this instance type.
+    pub fn core_type_count(&self) -> u32 {
+        self.0.core_types_added
+    }
+
+    /// Gets the number of types that have been added or aliased in this instance type.
+    pub fn type_count(&self) -> u32 {
+        self.0.types_added
+    }
+
+    /// Gets the number of instances that have been imported or exported or
+    /// aliased in this instance type.
+    pub fn instance_count(&self) -> u32 {
+        self.0.instances_added
+    }
+
+    /// Returns whether or not this instance type is empty.
+    pub fn is_empty(&self) -> bool {
+        self.0.num_added == 0
+    }
+
+    /// Returns the number of entries added to this instance types.
+    pub fn len(&self) -> u32 {
+        self.0.num_added
+    }
+}
+
+impl Encode for InstanceType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        sink.push(0x42);
+        self.0.num_added.encode(sink);
+        sink.extend(&self.0.bytes);
+    }
+}
+
+/// Used to encode component function types.
+#[derive(Debug)]
+pub struct ComponentFuncTypeEncoder<'a> {
+    async_encoded: bool,
+    params_encoded: bool,
+    results_encoded: bool,
+    sink: &'a mut Vec<u8>,
+}
+
+impl<'a> ComponentFuncTypeEncoder<'a> {
+    fn new(sink: &'a mut Vec<u8>) -> Self {
+        Self {
+            async_encoded: false,
+            params_encoded: false,
+            results_encoded: false,
+            sink,
+        }
+    }
+
+    /// Indicates whether this is an `async` function or not.
+    ///
+    /// If this function is not invoked then the function type will not be
+    /// `async`.
+    ///
+    /// # Panics
+    ///
+    /// This method will panic if parameters or results have already been
+    /// encoded.
+    pub fn async_(&mut self, is_async: bool) -> &mut Self {
+        assert!(!self.params_encoded);
+        assert!(!self.results_encoded);
+        assert!(!self.async_encoded);
+        self.async_encoded = true;
+        if is_async {
+            self.sink.push(0x43);
+        } else {
+            self.sink.push(0x40);
+        }
+        self
+    }
+
+    /// Defines named parameters.
+    ///
+    /// Parameters must be defined before defining results.
+    ///
+    /// # Panics
+    ///
+    /// This method will panic if the function is called twice since parameters
+    /// can only be encoded once.
+    pub fn params<'b, P, T>(&mut self, params: P) -> &mut Self
+    where
+        P: IntoIterator<Item = (&'b str, T)>,
+        P::IntoIter: ExactSizeIterator,
+        T: Into<ComponentValType>,
+    {
+        assert!(!self.params_encoded);
+        if !self.async_encoded {
+            self.async_(false);
+        }
+        self.params_encoded = true;
+        let params = params.into_iter();
+        params.len().encode(self.sink);
+        for (name, ty) in params {
+            name.encode(self.sink);
+            ty.into().encode(self.sink);
+        }
+        self
+    }
+
+    /// Defines a single unnamed result.
+    ///
+    /// This method cannot be used with `results`.
+    ///
+    /// # Panics
+    ///
+    /// This method will panic if the function is called twice, called before
+    /// the `params` method, or called in addition to the `results` method.
+    pub fn result(&mut self, ty: Option<ComponentValType>) -> &mut Self {
+        assert!(self.async_encoded);
+        assert!(self.params_encoded);
+        assert!(!self.results_encoded);
+        self.results_encoded = true;
+        encode_resultlist(self.sink, ty);
+        self
+    }
+}
+
+pub(crate) fn encode_resultlist(sink: &mut Vec<u8>, ty: Option<ComponentValType>) {
+    match ty {
+        Some(ty) => {
+            sink.push(0x00);
+            ty.encode(sink);
+        }
+        None => {
+            sink.push(0x01);
+            sink.push(0x00);
+        }
+    }
+}
+
+/// Used to encode component and instance types.
+#[derive(Debug)]
+pub struct ComponentTypeEncoder<'a>(&'a mut Vec<u8>);
+
+impl<'a> ComponentTypeEncoder<'a> {
+    /// Define a component type.
+    pub fn component(self, ty: &ComponentType) {
+        ty.encode(self.0);
+    }
+
+    /// Define an instance type.
+    pub fn instance(self, ty: &InstanceType) {
+        ty.encode(self.0);
+    }
+
+    /// Define a function type.
+    pub fn function(self) -> ComponentFuncTypeEncoder<'a> {
+        ComponentFuncTypeEncoder::new(self.0)
+    }
+
+    /// Define a defined component type.
+    ///
+    /// The returned encoder must be used before adding another type.
+    #[must_use = "the encoder must be used to encode the type"]
+    pub fn defined_type(self) -> ComponentDefinedTypeEncoder<'a> {
+        ComponentDefinedTypeEncoder(self.0)
+    }
+
+    /// Define a resource type.
+    pub fn resource(self, rep: ValType, dtor: Option<u32>) {
+        self.0.push(0x3f);
+        rep.encode(self.0);
+        match dtor {
+            Some(i) => {
+                self.0.push(0x01);
+                i.encode(self.0);
+            }
+            None => self.0.push(0x00),
+        }
+    }
+}
+
+/// Represents a primitive component value type.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum PrimitiveValType {
+    /// The type is a boolean.
+    Bool,
+    /// The type is a signed 8-bit integer.
+    S8,
+    /// The type is an unsigned 8-bit integer.
+    U8,
+    /// The type is a signed 16-bit integer.
+    S16,
+    /// The type is an unsigned 16-bit integer.
+    U16,
+    /// The type is a signed 32-bit integer.
+    S32,
+    /// The type is an unsigned 32-bit integer.
+    U32,
+    /// The type is a signed 64-bit integer.
+    S64,
+    /// The type is an unsigned 64-bit integer.
+    U64,
+    /// The type is a 32-bit floating point number with only one NaN.
+    F32,
+    /// The type is a 64-bit floating point number with only one NaN.
+    F64,
+    /// The type is a Unicode character.
+    Char,
+    /// The type is a string.
+    String,
+    /// Type for `error-context` added with async support in the component model.
+    ErrorContext,
+}
+
+impl Encode for PrimitiveValType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        sink.push(match self {
+            Self::Bool => 0x7f,
+            Self::S8 => 0x7e,
+            Self::U8 => 0x7d,
+            Self::S16 => 0x7c,
+            Self::U16 => 0x7b,
+            Self::S32 => 0x7a,
+            Self::U32 => 0x79,
+            Self::S64 => 0x78,
+            Self::U64 => 0x77,
+            Self::F32 => 0x76,
+            Self::F64 => 0x75,
+            Self::Char => 0x74,
+            Self::String => 0x73,
+            Self::ErrorContext => 0x64,
+        });
+    }
+}
+
+/// Represents a component value type.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum ComponentValType {
+    /// The value is a primitive type.
+    Primitive(PrimitiveValType),
+    /// The value is to a defined value type.
+    ///
+    /// The type index must be to a value type.
+    Type(u32),
+}
+
+impl Encode for ComponentValType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            Self::Primitive(ty) => ty.encode(sink),
+            Self::Type(index) => (*index as i64).encode(sink),
+        }
+    }
+}
+
+impl From<PrimitiveValType> for ComponentValType {
+    fn from(ty: PrimitiveValType) -> Self {
+        Self::Primitive(ty)
+    }
+}
+
+/// Used for encoding component defined types.
+#[derive(Debug)]
+pub struct ComponentDefinedTypeEncoder<'a>(&'a mut Vec<u8>);
+
+impl ComponentDefinedTypeEncoder<'_> {
+    /// Define a primitive value type.
+    pub fn primitive(self, ty: PrimitiveValType) {
+        ty.encode(self.0);
+    }
+
+    /// Define a record type.
+    pub fn record<'a, F, T>(self, fields: F)
+    where
+        F: IntoIterator<Item = (&'a str, T)>,
+        F::IntoIter: ExactSizeIterator,
+        T: Into<ComponentValType>,
+    {
+        let fields = fields.into_iter();
+        self.0.push(0x72);
+        fields.len().encode(self.0);
+        for (name, ty) in fields {
+            name.encode(self.0);
+            ty.into().encode(self.0);
+        }
+    }
+
+    /// Define a variant type.
+    pub fn variant<'a, C>(self, cases: C)
+    where
+        C: IntoIterator<Item = (&'a str, Option<ComponentValType>, Option<u32>)>,
+        C::IntoIter: ExactSizeIterator,
+    {
+        let cases = cases.into_iter();
+        self.0.push(0x71);
+        cases.len().encode(self.0);
+        for (name, ty, refines) in cases {
+            name.encode(self.0);
+            ty.encode(self.0);
+            refines.encode(self.0);
+        }
+    }
+
+    /// Define a list type.
+    pub fn list(self, ty: impl Into<ComponentValType>) {
+        self.0.push(0x70);
+        ty.into().encode(self.0);
+    }
+
+    /// Define a map type.
+    pub fn map(self, key: impl Into<ComponentValType>, value: impl Into<ComponentValType>) {
+        self.0.push(0x63);
+        key.into().encode(self.0);
+        value.into().encode(self.0);
+    }
+
+    /// Define a fixed size list type.
+    pub fn fixed_size_list(self, ty: impl Into<ComponentValType>, elements: u32) {
+        self.0.push(0x67);
+        ty.into().encode(self.0);
+        elements.encode(self.0);
+    }
+
+    /// Define a tuple type.
+    pub fn tuple<I, T>(self, types: I)
+    where
+        I: IntoIterator<Item = T>,
+        I::IntoIter: ExactSizeIterator,
+        T: Into<ComponentValType>,
+    {
+        let types = types.into_iter();
+        self.0.push(0x6F);
+        types.len().encode(self.0);
+        for ty in types {
+            ty.into().encode(self.0);
+        }
+    }
+
+    /// Define a flags type.
+    pub fn flags<'a, I>(self, names: I)
+    where
+        I: IntoIterator<Item = &'a str>,
+        I::IntoIter: ExactSizeIterator,
+    {
+        let names = names.into_iter();
+        self.0.push(0x6E);
+        names.len().encode(self.0);
+        for name in names {
+            name.encode(self.0);
+        }
+    }
+
+    /// Define an enum type.
+    pub fn enum_type<'a, I>(self, tags: I)
+    where
+        I: IntoIterator<Item = &'a str>,
+        I::IntoIter: ExactSizeIterator,
+    {
+        let tags = tags.into_iter();
+        self.0.push(0x6D);
+        tags.len().encode(self.0);
+        for tag in tags {
+            tag.encode(self.0);
+        }
+    }
+
+    /// Define an option type.
+    pub fn option(self, ty: impl Into<ComponentValType>) {
+        self.0.push(0x6B);
+        ty.into().encode(self.0);
+    }
+
+    /// Define a result type.
+    pub fn result(self, ok: Option<ComponentValType>, err: Option<ComponentValType>) {
+        self.0.push(0x6A);
+        ok.encode(self.0);
+        err.encode(self.0);
+    }
+
+    /// Define a `own` handle type
+    pub fn own(self, idx: u32) {
+        self.0.push(0x69);
+        idx.encode(self.0);
+    }
+
+    /// Define a `borrow` handle type
+    pub fn borrow(self, idx: u32) {
+        self.0.push(0x68);
+        idx.encode(self.0);
+    }
+
+    /// Define a `future` type with the specified payload.
+    pub fn future(self, payload: Option<ComponentValType>) {
+        self.0.push(0x65);
+        payload.encode(self.0);
+    }
+
+    /// Define a `stream` type with the specified payload.
+    pub fn stream(self, payload: Option<ComponentValType>) {
+        self.0.push(0x66);
+        payload.encode(self.0);
+    }
+}
+
+/// An encoder for the type section of WebAssembly components.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{Component, ComponentTypeSection, PrimitiveValType};
+///
+/// let mut types = ComponentTypeSection::new();
+///
+/// // Define a function type of `[string, string] -> string`.
+/// types
+///   .function()
+///   .params(
+///     [
+///       ("a", PrimitiveValType::String),
+///       ("b", PrimitiveValType::String)
+///     ]
+///   )
+///   .result(Some(PrimitiveValType::String.into()));
+///
+/// let mut component = Component::new();
+/// component.section(&types);
+///
+/// let bytes = component.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct ComponentTypeSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl ComponentTypeSection {
+    /// Create a new component type section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of types in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Encode a type into this section.
+    ///
+    /// The returned encoder must be finished before adding another type.
+    #[must_use = "the encoder must be used to encode the type"]
+    pub fn ty(&mut self) -> ComponentTypeEncoder<'_> {
+        self.num_added += 1;
+        ComponentTypeEncoder(&mut self.bytes)
+    }
+
+    /// Define a component type in this type section.
+    pub fn component(&mut self, ty: &ComponentType) -> &mut Self {
+        self.ty().component(ty);
+        self
+    }
+
+    /// Define an instance type in this type section.
+    pub fn instance(&mut self, ty: &InstanceType) -> &mut Self {
+        self.ty().instance(ty);
+        self
+    }
+
+    /// Define a function type in this type section.
+    pub fn function(&mut self) -> ComponentFuncTypeEncoder<'_> {
+        self.ty().function()
+    }
+
+    /// Add a component defined type to this type section.
+    ///
+    /// The returned encoder must be used before adding another type.
+    #[must_use = "the encoder must be used to encode the type"]
+    pub fn defined_type(&mut self) -> ComponentDefinedTypeEncoder<'_> {
+        self.ty().defined_type()
+    }
+
+    /// Defines a new resource type.
+    pub fn resource(&mut self, rep: ValType, dtor: Option<u32>) -> &mut Self {
+        self.ty().resource(rep, dtor);
+        self
+    }
+}
+
+impl Encode for ComponentTypeSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl ComponentSection for ComponentTypeSection {
+    fn id(&self) -> u8 {
+        ComponentSectionId::Type.into()
+    }
+}

vendor/wasm-encoder/src/core.rs

@@ -0,0 +1,179 @@
+mod branch_hints;
+mod code;
+mod custom;
+mod data;
+mod dump;
+mod elements;
+mod exports;
+mod functions;
+mod globals;
+mod imports;
+mod instructions;
+mod linking;
+mod memories;
+mod names;
+mod producers;
+mod start;
+mod tables;
+mod tags;
+mod types;
+
+pub use branch_hints::*;
+pub use code::*;
+pub use custom::*;
+pub use data::*;
+pub use dump::*;
+pub use elements::*;
+pub use exports::*;
+pub use functions::*;
+pub use globals::*;
+pub use imports::*;
+pub use instructions::*;
+pub use linking::*;
+pub use memories::*;
+pub use names::*;
+pub use producers::*;
+pub use start::*;
+pub use tables::*;
+pub use tags::*;
+pub use types::*;
+
+use crate::Encode;
+use alloc::vec::Vec;
+
+pub(crate) const CORE_FUNCTION_SORT: u8 = 0x00;
+pub(crate) const CORE_TABLE_SORT: u8 = 0x01;
+pub(crate) const CORE_MEMORY_SORT: u8 = 0x02;
+pub(crate) const CORE_GLOBAL_SORT: u8 = 0x03;
+pub(crate) const CORE_TAG_SORT: u8 = 0x04;
+pub(crate) const CORE_FUNCTION_EXACT_SORT: u8 = 0x20;
+
+/// A WebAssembly module section.
+///
+/// Various builders defined in this crate already implement this trait, but you
+/// can also implement it yourself for your own custom section builders, or use
+/// `RawSection` to use a bunch of raw bytes as a section.
+pub trait Section: Encode {
+    /// Gets the section identifier for this section.
+    fn id(&self) -> u8;
+
+    /// Appends this section to the specified destination list of bytes.
+    fn append_to(&self, dst: &mut Vec<u8>) {
+        dst.push(self.id());
+        self.encode(dst);
+    }
+}
+
+/// Known section identifiers of WebAssembly modules.
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd)]
+#[repr(u8)]
+pub enum SectionId {
+    /// The custom section.
+    Custom = 0,
+    /// The type section.
+    Type = 1,
+    /// The import section.
+    Import = 2,
+    /// The function section.
+    Function = 3,
+    /// The table section.
+    Table = 4,
+    /// The memory section.
+    Memory = 5,
+    /// The global section.
+    Global = 6,
+    /// The export section.
+    Export = 7,
+    /// The start section.
+    Start = 8,
+    /// The element section.
+    Element = 9,
+    /// The code section.
+    Code = 10,
+    /// The data section.
+    Data = 11,
+    /// The data count section.
+    DataCount = 12,
+    /// The tag section.
+    ///
+    /// This section is supported by the exception handling proposal.
+    Tag = 13,
+}
+
+impl From<SectionId> for u8 {
+    #[inline]
+    fn from(id: SectionId) -> u8 {
+        id as u8
+    }
+}
+
+impl Encode for SectionId {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        sink.push(*self as u8);
+    }
+}
+
+/// Represents a WebAssembly component that is being encoded.
+///
+/// Sections within a WebAssembly module are encoded in a specific order.
+///
+/// Modules may also added as a section to a WebAssembly component.
+#[derive(Clone, Debug)]
+pub struct Module {
+    pub(crate) bytes: Vec<u8>,
+}
+
+impl Module {
+    /// The 8-byte header at the beginning of all core wasm modules.
+    #[rustfmt::skip]
+    pub const HEADER: [u8; 8] = [
+        // Magic
+        0x00, 0x61, 0x73, 0x6D,
+        // Version
+        0x01, 0x00, 0x00, 0x00,
+    ];
+
+    /// Begin writing a new `Module`.
+    #[rustfmt::skip]
+    pub fn new() -> Self {
+        Module {
+            bytes: Self::HEADER.to_vec(),
+        }
+    }
+
+    /// Write a section into this module.
+    ///
+    /// It is your responsibility to define the sections in the [proper
+    /// order](https://webassembly.github.io/spec/core/binary/modules.html#binary-module),
+    /// and to ensure that each kind of section (other than custom sections) is
+    /// only defined once. While this is a potential footgun, it also allows you
+    /// to use this crate to easily construct test cases for bad Wasm module
+    /// encodings.
+    pub fn section(&mut self, section: &impl Section) -> &mut Self {
+        self.bytes.push(section.id());
+        section.encode(&mut self.bytes);
+        self
+    }
+
+    /// Get the encoded Wasm module as a slice.
+    pub fn as_slice(&self) -> &[u8] {
+        &self.bytes
+    }
+
+    /// Give the current size of the module in bytes.
+    pub fn len(&self) -> usize {
+        self.bytes.len()
+    }
+
+    /// Finish writing this Wasm module and extract ownership of the encoded
+    /// bytes.
+    pub fn finish(self) -> Vec<u8> {
+        self.bytes
+    }
+}
+
+impl Default for Module {
+    fn default() -> Self {
+        Self::new()
+    }
+}

vendor/wasm-encoder/src/core/branch_hints.rs

@@ -0,0 +1,127 @@
+use crate::{CustomSection, Encode, Section, SectionId};
+use alloc::borrow::Cow;
+use alloc::vec::Vec;
+
+/// Helper structure to encode the `metadata.code.branch_hint` custom section.
+///
+/// This section was defined in the branch-hinting proposal for WebAssembly:
+/// <https://github.com/WebAssembly/branch-hinting>.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::*;
+///
+/// let mut module = Module::new();
+///
+/// let mut types = TypeSection::new();
+/// types.ty().function([], []);
+/// module.section(&types);
+///
+/// let mut funcs = FunctionSection::new();
+/// funcs.function(0);
+/// module.section(&funcs);
+///
+/// let mut code = CodeSection::new();
+/// let mut body = Function::new([]);
+///
+/// body.instructions().i32_const(1);
+/// let if_offset = body.byte_len();
+/// body.instructions()
+///     .if_(BlockType::Empty)
+///     .end()
+///     .end();
+/// code.function(&body);
+///
+/// let mut hints = BranchHints::new();
+/// hints.function_hints(0, [BranchHint {
+///     branch_func_offset: if_offset as u32,
+///     branch_hint_value: 1, // taken
+/// }]);
+/// module.section(&hints);
+/// module.section(&code);
+///
+/// let wasm = module.finish();
+/// let wat = wasmprinter::print_bytes(&wasm).unwrap();
+/// assert_eq!(wat, r#"(module
+///   (type (;0;) (func))
+///   (func (;0;) (type 0)
+///     i32.const 1
+///     (@metadata.code.branch_hint "\01")
+///     if ;; label = @1
+///     end
+///   )
+/// )
+/// "#);
+///
+/// ```
+#[derive(Default, Debug)]
+pub struct BranchHints {
+    bytes: Vec<u8>,
+    num_hints: u32,
+}
+
+/// A single branch hint within a function.
+#[derive(Debug, Clone, Copy)]
+pub struct BranchHint {
+    /// The offset, in bytes from the beginning of the function, to the `if`
+    /// instruction that this is hinting.
+    pub branch_func_offset: u32,
+    /// The value of the hint, 0 for not taken and 1 for taken.
+    pub branch_hint_value: u32,
+}
+
+impl BranchHints {
+    /// Construct an empty encoder for the branch hints custom section.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Adds a new set of function hints for the `func` specified.
+    pub fn function_hints<I>(&mut self, func: u32, hints: I)
+    where
+        I: IntoIterator<Item = BranchHint>,
+        I::IntoIter: ExactSizeIterator,
+    {
+        self.num_hints += 1;
+        func.encode(&mut self.bytes);
+        let hints = hints.into_iter();
+        hints.len().encode(&mut self.bytes);
+        for hint in hints {
+            hint.branch_func_offset.encode(&mut self.bytes);
+            1u32.encode(&mut self.bytes);
+            hint.branch_hint_value.encode(&mut self.bytes);
+        }
+    }
+
+    /// Returns if this is an empty section.
+    pub fn is_empty(&self) -> bool {
+        self.num_hints == 0
+    }
+
+    /// Returns the number of functions that have hints registered in this
+    /// sectino.
+    pub fn len(&self) -> u32 {
+        self.num_hints
+    }
+}
+
+impl Encode for BranchHints {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        let mut data = Vec::new();
+        self.num_hints.encode(&mut data);
+        data.extend(&self.bytes);
+
+        CustomSection {
+            name: "metadata.code.branch_hint".into(),
+            data: Cow::Borrowed(&data),
+        }
+        .encode(sink);
+    }
+}
+
+impl Section for BranchHints {
+    fn id(&self) -> u8 {
+        SectionId::Custom.into()
+    }
+}

vendor/wasm-encoder/src/core/custom.rs

@@ -0,0 +1,74 @@
+use crate::{Encode, Section, SectionId, encoding_size};
+use alloc::borrow::Cow;
+use alloc::vec::Vec;
+
+/// A custom section holding arbitrary data.
+#[derive(Clone, Debug, PartialEq)]
+pub struct CustomSection<'a> {
+    /// The name of this custom section.
+    pub name: Cow<'a, str>,
+    /// This custom section's data.
+    pub data: Cow<'a, [u8]>,
+}
+
+impl Encode for CustomSection<'_> {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        let encoded_name_len = encoding_size(u32::try_from(self.name.len()).unwrap());
+        (encoded_name_len + self.name.len() + self.data.len()).encode(sink);
+        self.name.encode(sink);
+        sink.extend(&*self.data);
+    }
+}
+
+impl Section for CustomSection<'_> {
+    fn id(&self) -> u8 {
+        SectionId::Custom.into()
+    }
+}
+
+/// A raw custom section where the bytes specified contain the leb-encoded
+/// length of the custom section, the custom section's name, and the custom
+/// section's data.
+#[derive(Clone, Debug)]
+pub struct RawCustomSection<'a>(pub &'a [u8]);
+
+impl Encode for RawCustomSection<'_> {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        sink.extend(self.0);
+    }
+}
+
+impl Section for RawCustomSection<'_> {
+    fn id(&self) -> u8 {
+        SectionId::Custom.into()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use alloc::vec;
+
+    #[test]
+    fn test_custom_section() {
+        let custom = CustomSection {
+            name: "test".into(),
+            data: Cow::Borrowed(&[11, 22, 33, 44]),
+        };
+
+        let mut encoded = vec![];
+        custom.encode(&mut encoded);
+
+        #[rustfmt::skip]
+        assert_eq!(encoded, vec![
+            // LEB128 length of section.
+            9,
+            // LEB128 length of name.
+            4,
+            // Name.
+            b't', b'e', b's', b't',
+            // Data.
+            11, 22, 33, 44,
+        ]);
+    }
+}

vendor/wasm-encoder/src/core/data.rs

@@ -0,0 +1,187 @@
+use crate::{ConstExpr, Encode, Section, SectionId, encode_section, encoding_size};
+use alloc::vec::Vec;
+
+/// An encoder for the data section.
+///
+/// Data sections are only supported for modules.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{
+///     ConstExpr, DataSection, Instruction, MemorySection, MemoryType,
+///     Module,
+/// };
+///
+/// let mut memory = MemorySection::new();
+/// memory.memory(MemoryType {
+///     minimum: 1,
+///     maximum: None,
+///     memory64: false,
+///     shared: false,
+///     page_size_log2: None,
+/// });
+///
+/// let mut data = DataSection::new();
+/// let memory_index = 0;
+/// let offset = ConstExpr::i32_const(42);
+/// let segment_data = b"hello";
+/// data.active(memory_index, &offset, segment_data.iter().copied());
+///
+/// let mut module = Module::new();
+/// module
+///     .section(&memory)
+///     .section(&data);
+///
+/// let wasm_bytes = module.finish();
+/// ```
+#[derive(Clone, Default, Debug)]
+pub struct DataSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+/// A segment in the data section.
+#[derive(Clone, Debug)]
+pub struct DataSegment<'a, D> {
+    /// This data segment's mode.
+    pub mode: DataSegmentMode<'a>,
+    /// This data segment's data.
+    pub data: D,
+}
+
+/// A data segment's mode.
+#[derive(Clone, Debug)]
+pub enum DataSegmentMode<'a> {
+    /// An active data segment.
+    Active {
+        /// The memory this segment applies to.
+        memory_index: u32,
+        /// The offset where this segment's data is initialized at.
+        offset: &'a ConstExpr,
+    },
+    /// A passive data segment.
+    ///
+    /// Passive data segments are part of the bulk memory proposal.
+    Passive,
+}
+
+impl DataSection {
+    /// Create a new data section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of data segments in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define a data segment.
+    pub fn segment<D>(&mut self, segment: DataSegment<D>) -> &mut Self
+    where
+        D: IntoIterator<Item = u8>,
+        D::IntoIter: ExactSizeIterator,
+    {
+        match segment.mode {
+            DataSegmentMode::Passive => {
+                self.bytes.push(0x01);
+            }
+            DataSegmentMode::Active {
+                memory_index: 0,
+                offset,
+            } => {
+                self.bytes.push(0x00);
+                offset.encode(&mut self.bytes);
+            }
+            DataSegmentMode::Active {
+                memory_index,
+                offset,
+            } => {
+                self.bytes.push(0x02);
+                memory_index.encode(&mut self.bytes);
+                offset.encode(&mut self.bytes);
+            }
+        }
+
+        let data = segment.data.into_iter();
+        data.len().encode(&mut self.bytes);
+        self.bytes.extend(data);
+
+        self.num_added += 1;
+        self
+    }
+
+    /// Define an active data segment.
+    pub fn active<D>(&mut self, memory_index: u32, offset: &ConstExpr, data: D) -> &mut Self
+    where
+        D: IntoIterator<Item = u8>,
+        D::IntoIter: ExactSizeIterator,
+    {
+        self.segment(DataSegment {
+            mode: DataSegmentMode::Active {
+                memory_index,
+                offset,
+            },
+            data,
+        })
+    }
+
+    /// Define a passive data segment.
+    ///
+    /// Passive data segments are part of the bulk memory proposal.
+    pub fn passive<D>(&mut self, data: D) -> &mut Self
+    where
+        D: IntoIterator<Item = u8>,
+        D::IntoIter: ExactSizeIterator,
+    {
+        self.segment(DataSegment {
+            mode: DataSegmentMode::Passive,
+            data,
+        })
+    }
+
+    /// Copy an already-encoded data segment into this data section.
+    pub fn raw(&mut self, already_encoded_data_segment: &[u8]) -> &mut Self {
+        self.bytes.extend_from_slice(already_encoded_data_segment);
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for DataSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl Section for DataSection {
+    fn id(&self) -> u8 {
+        SectionId::Data.into()
+    }
+}
+
+/// An encoder for the data count section.
+#[derive(Clone, Copy, Debug)]
+pub struct DataCountSection {
+    /// The number of segments in the data section.
+    pub count: u32,
+}
+
+impl Encode for DataCountSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encoding_size(self.count).encode(sink);
+        self.count.encode(sink);
+    }
+}
+
+impl Section for DataCountSection {
+    fn id(&self) -> u8 {
+        SectionId::DataCount.into()
+    }
+}

vendor/wasm-encoder/src/core/dump.rs

@@ -0,0 +1,629 @@
+use crate::{CustomSection, Encode, Ieee32, Ieee64, Section};
+use alloc::borrow::Cow;
+use alloc::string::String;
+use alloc::vec;
+use alloc::vec::Vec;
+
+/// The "core" custom section for coredumps, as described in the
+/// [tool-conventions
+/// repository](https://github.com/WebAssembly/tool-conventions/blob/main/Coredump.md).
+///
+/// There are four sections that comprise a core dump:
+///     - "core", which contains the name of the core dump
+///     - "coremodules", a listing of modules
+///     - "coreinstances", a listing of module instances
+///     - "corestack", a listing of frames for a specific thread
+///
+/// # Example of how these could be constructed and encoded into a module:
+///
+/// ```
+/// use wasm_encoder::{
+///     CoreDumpInstancesSection, CoreDumpModulesSection, CoreDumpSection, CoreDumpStackSection,
+///     CoreDumpValue, Module,
+/// };
+/// let core = CoreDumpSection::new("MyModule.wasm");
+///
+/// let mut modules = CoreDumpModulesSection::new();
+/// modules.module("my_module");
+///
+/// let mut instances = CoreDumpInstancesSection::new();
+/// let module_idx = 0;
+/// let memories = vec![1];
+/// let globals = vec![2];
+/// instances.instance(module_idx, memories, globals);
+///
+/// let mut thread = CoreDumpStackSection::new("main");
+/// let instance_index = 0;
+/// let func_index = 42;
+/// let code_offset = 0x1234;
+/// let locals = vec![CoreDumpValue::I32(1)];
+/// let stack = vec![CoreDumpValue::I32(2)];
+/// thread.frame(instance_index, func_index, code_offset, locals, stack);
+///
+/// let mut module = Module::new();
+/// module.section(&core);
+/// module.section(&modules);
+/// module.section(&instances);
+/// module.section(&thread);
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct CoreDumpSection {
+    name: String,
+}
+
+impl CoreDumpSection {
+    /// Create a new core dump section encoder
+    pub fn new(name: impl Into<String>) -> Self {
+        let name = name.into();
+        CoreDumpSection { name }
+    }
+
+    /// View the encoded section as a CustomSection.
+    fn as_custom<'a>(&'a self) -> CustomSection<'a> {
+        let mut data = vec![0];
+        self.name.encode(&mut data);
+        CustomSection {
+            name: "core".into(),
+            data: Cow::Owned(data),
+        }
+    }
+}
+
+impl Encode for CoreDumpSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.as_custom().encode(sink);
+    }
+}
+
+impl Section for CoreDumpSection {
+    fn id(&self) -> u8 {
+        crate::core::SectionId::Custom as u8
+    }
+}
+
+/// The "coremodules" custom section for coredumps which lists the names of the
+/// modules
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{CoreDumpModulesSection, Module};
+/// let mut modules_section = CoreDumpModulesSection::new();
+/// modules_section.module("my_module");
+/// let mut module = Module::new();
+/// module.section(&modules_section);
+/// ```
+#[derive(Debug)]
+pub struct CoreDumpModulesSection {
+    num_added: u32,
+    bytes: Vec<u8>,
+}
+
+impl CoreDumpModulesSection {
+    /// Create a new core dump modules section encoder.
+    pub fn new() -> Self {
+        CoreDumpModulesSection {
+            bytes: vec![],
+            num_added: 0,
+        }
+    }
+
+    /// View the encoded section as a CustomSection.
+    pub fn as_custom(&self) -> CustomSection<'_> {
+        let mut data = vec![];
+        self.num_added.encode(&mut data);
+        data.extend(self.bytes.iter().copied());
+        CustomSection {
+            name: "coremodules".into(),
+            data: Cow::Owned(data),
+        }
+    }
+
+    /// Encode a module name into the section's bytes.
+    pub fn module(&mut self, module_name: impl AsRef<str>) -> &mut Self {
+        self.bytes.push(0x0);
+        module_name.as_ref().encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// The number of modules that are encoded in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+}
+
+impl Encode for CoreDumpModulesSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.as_custom().encode(sink);
+    }
+}
+
+impl Section for CoreDumpModulesSection {
+    fn id(&self) -> u8 {
+        crate::core::SectionId::Custom as u8
+    }
+}
+
+/// The "coreinstances" section for the core dump
+#[derive(Debug)]
+pub struct CoreDumpInstancesSection {
+    num_added: u32,
+    bytes: Vec<u8>,
+}
+
+impl CoreDumpInstancesSection {
+    /// Create a new core dump instances section encoder.
+    pub fn new() -> Self {
+        CoreDumpInstancesSection {
+            bytes: vec![],
+            num_added: 0,
+        }
+    }
+
+    /// View the encoded section as a CustomSection.
+    pub fn as_custom(&self) -> CustomSection<'_> {
+        let mut data = vec![];
+        self.num_added.encode(&mut data);
+        data.extend(self.bytes.iter().copied());
+        CustomSection {
+            name: "coreinstances".into(),
+            data: Cow::Owned(data),
+        }
+    }
+
+    /// Encode an instance into the section's bytes.
+    pub fn instance<M, G>(&mut self, module_index: u32, memories: M, globals: G) -> &mut Self
+    where
+        M: IntoIterator<Item = u32>,
+        <M as IntoIterator>::IntoIter: ExactSizeIterator,
+        G: IntoIterator<Item = u32>,
+        <G as IntoIterator>::IntoIter: ExactSizeIterator,
+    {
+        self.bytes.push(0x0);
+        module_index.encode(&mut self.bytes);
+        crate::encode_vec(memories, &mut self.bytes);
+        crate::encode_vec(globals, &mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// The number of modules that are encoded in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+}
+
+impl Encode for CoreDumpInstancesSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.as_custom().encode(sink);
+    }
+}
+
+impl Section for CoreDumpInstancesSection {
+    fn id(&self) -> u8 {
+        crate::core::SectionId::Custom as u8
+    }
+}
+
+/// A "corestack" custom section as described in the [tool-conventions
+/// repository](https://github.com/WebAssembly/tool-conventions/blob/main/Coredump.md)
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{CoreDumpStackSection, Module, CoreDumpValue};
+/// let mut thread = CoreDumpStackSection::new("main");
+///
+/// let instance_index = 0;
+/// let func_index = 42;
+/// let code_offset = 0x1234;
+/// let locals = vec![CoreDumpValue::I32(1)];
+/// let stack = vec![CoreDumpValue::I32(2)];
+/// thread.frame(instance_index, func_index, code_offset, locals, stack);
+///
+/// let mut module = Module::new();
+/// module.section(&thread);
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct CoreDumpStackSection {
+    frame_bytes: Vec<u8>,
+    count: u32,
+    name: String,
+}
+
+impl CoreDumpStackSection {
+    /// Create a new core dump stack section encoder.
+    pub fn new(name: impl Into<String>) -> Self {
+        let name = name.into();
+        CoreDumpStackSection {
+            frame_bytes: Vec::new(),
+            count: 0,
+            name,
+        }
+    }
+
+    /// Add a stack frame to this coredump stack section.
+    pub fn frame<L, S>(
+        &mut self,
+        instanceidx: u32,
+        funcidx: u32,
+        codeoffset: u32,
+        locals: L,
+        stack: S,
+    ) -> &mut Self
+    where
+        L: IntoIterator<Item = CoreDumpValue>,
+        <L as IntoIterator>::IntoIter: ExactSizeIterator,
+        S: IntoIterator<Item = CoreDumpValue>,
+        <S as IntoIterator>::IntoIter: ExactSizeIterator,
+    {
+        self.count += 1;
+        self.frame_bytes.push(0);
+        instanceidx.encode(&mut self.frame_bytes);
+        funcidx.encode(&mut self.frame_bytes);
+        codeoffset.encode(&mut self.frame_bytes);
+        crate::encode_vec(locals, &mut self.frame_bytes);
+        crate::encode_vec(stack, &mut self.frame_bytes);
+        self
+    }
+
+    /// View the encoded section as a CustomSection.
+    pub fn as_custom<'a>(&'a self) -> CustomSection<'a> {
+        let mut data = vec![0];
+        self.name.encode(&mut data);
+        self.count.encode(&mut data);
+        data.extend(&self.frame_bytes);
+        CustomSection {
+            name: "corestack".into(),
+            data: Cow::Owned(data),
+        }
+    }
+}
+
+impl Encode for CoreDumpStackSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.as_custom().encode(sink);
+    }
+}
+
+impl Section for CoreDumpStackSection {
+    fn id(&self) -> u8 {
+        crate::core::SectionId::Custom as u8
+    }
+}
+
+/// Local and stack values are encoded using one byte for the type (similar to
+/// Wasm's Number Types) followed by bytes representing the actual value
+/// See the tool-conventions repo for more details.
+#[derive(Clone, Debug)]
+pub enum CoreDumpValue {
+    /// a missing value (usually missing because it was optimized out)
+    Missing,
+    /// An i32 value
+    I32(i32),
+    /// An i64 value
+    I64(i64),
+    /// An f32 value
+    F32(Ieee32),
+    /// An f64 value
+    F64(Ieee64),
+}
+
+impl Encode for CoreDumpValue {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            CoreDumpValue::Missing => sink.push(0x01),
+            CoreDumpValue::I32(x) => {
+                sink.push(0x7F);
+                x.encode(sink);
+            }
+            CoreDumpValue::I64(x) => {
+                sink.push(0x7E);
+                x.encode(sink);
+            }
+            CoreDumpValue::F32(x) => {
+                sink.push(0x7D);
+                x.encode(sink);
+            }
+            CoreDumpValue::F64(x) => {
+                sink.push(0x7C);
+                x.encode(sink);
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::Module;
+    use wasmparser::{KnownCustom, Parser, Payload};
+
+    // Create new core dump section and test whether it is properly encoded and
+    // parsed back out by wasmparser
+    #[test]
+    fn test_roundtrip_core() {
+        let core = CoreDumpSection::new("test.wasm");
+        let mut module = Module::new();
+        module.section(&core);
+
+        let wasm_bytes = module.finish();
+
+        let mut parser = Parser::new(0).parse_all(&wasm_bytes);
+        match parser.next() {
+            Some(Ok(Payload::Version { .. })) => {}
+            _ => panic!(""),
+        }
+
+        let payload = parser
+            .next()
+            .expect("parser is not empty")
+            .expect("element is a payload");
+        match payload {
+            Payload::CustomSection(section) => {
+                assert_eq!(section.name(), "core");
+                let core = match section.as_known() {
+                    KnownCustom::CoreDump(s) => s,
+                    _ => panic!("not coredump"),
+                };
+                assert_eq!(core.name, "test.wasm");
+            }
+            _ => panic!("unexpected payload"),
+        }
+    }
+
+    #[test]
+    fn test_roundtrip_coremodules() {
+        let mut coremodules = CoreDumpModulesSection::new();
+        coremodules.module("test_module");
+
+        let mut module = crate::Module::new();
+        module.section(&coremodules);
+
+        let wasm_bytes = module.finish();
+
+        let mut parser = Parser::new(0).parse_all(&wasm_bytes);
+        match parser.next() {
+            Some(Ok(Payload::Version { .. })) => {}
+            _ => panic!(""),
+        }
+
+        let payload = parser
+            .next()
+            .expect("parser is not empty")
+            .expect("element is a payload");
+        match payload {
+            Payload::CustomSection(section) => {
+                assert_eq!(section.name(), "coremodules");
+                let modules = match section.as_known() {
+                    KnownCustom::CoreDumpModules(s) => s,
+                    _ => panic!("not coremodules"),
+                };
+                assert_eq!(modules.modules[0], "test_module");
+            }
+            _ => panic!("unexpected payload"),
+        }
+    }
+
+    #[test]
+    fn test_roundtrip_coreinstances() {
+        let mut coreinstances = CoreDumpInstancesSection::new();
+        let module_index = 0;
+        let memories = vec![42];
+        let globals = vec![17];
+        coreinstances.instance(module_index, memories, globals);
+
+        let mut module = Module::new();
+        module.section(&coreinstances);
+        let wasm_bytes = module.finish();
+
+        let mut parser = Parser::new(0).parse_all(&wasm_bytes);
+        match parser.next() {
+            Some(Ok(Payload::Version { .. })) => {}
+            _ => panic!(""),
+        }
+
+        let payload = parser
+            .next()
+            .expect("parser is not empty")
+            .expect("element is a payload");
+        match payload {
+            Payload::CustomSection(section) => {
+                assert_eq!(section.name(), "coreinstances");
+                let coreinstances = match section.as_known() {
+                    KnownCustom::CoreDumpInstances(s) => s,
+                    _ => panic!("not coreinstances"),
+                };
+                assert_eq!(coreinstances.instances.len(), 1);
+                let instance = coreinstances
+                    .instances
+                    .first()
+                    .expect("instance is encoded");
+                assert_eq!(instance.module_index, 0);
+                assert_eq!(instance.memories.len(), 1);
+                assert_eq!(instance.globals.len(), 1);
+            }
+            _ => panic!("unexpected payload"),
+        }
+    }
+
+    // Create new corestack section and test whether it is properly encoded and
+    // parsed back out by wasmparser
+    #[test]
+    fn test_roundtrip_corestack() {
+        let mut corestack = CoreDumpStackSection::new("main");
+        corestack.frame(
+            0,
+            12,
+            0,
+            vec![CoreDumpValue::I32(10)],
+            vec![CoreDumpValue::I32(42)],
+        );
+        let mut module = Module::new();
+        module.section(&corestack);
+        let wasm_bytes = module.finish();
+
+        let mut parser = Parser::new(0).parse_all(&wasm_bytes);
+        match parser.next() {
+            Some(Ok(Payload::Version { .. })) => {}
+            _ => panic!(""),
+        }
+
+        let payload = parser
+            .next()
+            .expect("parser is not empty")
+            .expect("element is a payload");
+        match payload {
+            Payload::CustomSection(section) => {
+                assert_eq!(section.name(), "corestack");
+                let corestack = match section.as_known() {
+                    KnownCustom::CoreDumpStack(s) => s,
+                    _ => panic!("not a corestack section"),
+                };
+                assert_eq!(corestack.name, "main");
+                assert_eq!(corestack.frames.len(), 1);
+                let frame = corestack
+                    .frames
+                    .first()
+                    .expect("frame is encoded in corestack");
+                assert_eq!(frame.instanceidx, 0);
+                assert_eq!(frame.funcidx, 12);
+                assert_eq!(frame.codeoffset, 0);
+                assert_eq!(frame.locals.len(), 1);
+                match frame.locals.first().expect("frame contains a local") {
+                    &wasmparser::CoreDumpValue::I32(val) => assert_eq!(val, 10),
+                    _ => panic!("unexpected local value"),
+                }
+                assert_eq!(frame.stack.len(), 1);
+                match frame.stack.first().expect("stack contains a value") {
+                    &wasmparser::CoreDumpValue::I32(val) => assert_eq!(val, 42),
+                    _ => panic!("unexpected stack value"),
+                }
+            }
+            _ => panic!("unexpected payload"),
+        }
+    }
+
+    #[test]
+    fn test_encode_coredump_section() {
+        let core = CoreDumpSection::new("test");
+
+        let mut encoded = vec![];
+        core.encode(&mut encoded);
+
+        #[rustfmt::skip]
+        assert_eq!(encoded, vec![
+            // section length
+            11,
+            // name length
+            4,
+            // section name (core)
+            b'c',b'o',b'r',b'e',
+            // process-info (0, data length, data)
+            0, 4, b't', b'e', b's', b't',
+        ]);
+    }
+
+    #[test]
+    fn test_encode_coremodules_section() {
+        let mut modules = CoreDumpModulesSection::new();
+        modules.module("mod1");
+        modules.module("mod2");
+
+        let mut encoded = vec![];
+        modules.encode(&mut encoded);
+
+        #[rustfmt::skip]
+        assert_eq!(encoded, vec![
+            // section length
+            25,
+            // name length
+            11,
+            // section name (coremodules)
+            b'c',b'o',b'r',b'e',b'm',b'o',b'd',b'u',b'l',b'e',b's',
+            // module count
+            2,
+            // 0x0, name-length, module name (mod1)
+            0x0, 4, b'm',b'o',b'd',b'1',
+            // 0x0, name-length, module name (mod2)
+            0x0, 4, b'm',b'o',b'd',b'2'
+        ]);
+    }
+
+    #[test]
+    fn test_encode_coreinstances_section() {
+        let mut instances = CoreDumpInstancesSection::new();
+        instances.instance(0, vec![42], vec![17]);
+
+        let mut encoded = vec![];
+        instances.encode(&mut encoded);
+
+        #[rustfmt::skip]
+        assert_eq!(encoded, vec![
+            // section length
+            21,
+            // name length
+            13,
+            // section name (coreinstances)
+            b'c',b'o',b'r',b'e',b'i',b'n',b's',b't',b'a',b'n',b'c',b'e',b's',
+            // instance count
+            1,
+            // 0x0, module_idx
+            0x0, 0,
+            // memories count, memories
+            1, 42,
+            // globals count, globals
+            1, 17
+        ]);
+    }
+
+    #[test]
+    fn test_encode_corestack_section() {
+        let mut thread = CoreDumpStackSection::new("main");
+        thread.frame(
+            0,
+            42,
+            51,
+            vec![CoreDumpValue::I32(1)],
+            vec![CoreDumpValue::I32(2)],
+        );
+
+        let mut encoded = vec![];
+        thread.encode(&mut encoded);
+
+        #[rustfmt::skip]
+        assert_eq!(
+            encoded,
+            vec![
+                // section length
+                27,
+                // length of name.
+                9,
+                // section name (corestack)
+                b'c',b'o',b'r',b'e',b's',b't',b'a',b'c',b'k',
+                // 0x0, thread name length
+                0, 4,
+                // thread name (main)
+                b'm',b'a',b'i',b'n',
+                // frame count
+                1,
+                // 0x0, instanceidx, funcidx, codeoffset
+                0, 0, 42, 51,
+                // local count
+                1,
+                // local value type
+                0x7F,
+                // local value
+                1,
+                // stack count
+                1,
+                // stack value type
+                0x7F,
+                // stack value
+                2
+
+            ]
+        );
+    }
+}

vendor/wasm-encoder/src/core/elements.rs

@@ -0,0 +1,225 @@
+use crate::{ConstExpr, Encode, RefType, Section, SectionId, encode_section};
+use alloc::borrow::Cow;
+use alloc::vec::Vec;
+
+/// An encoder for the element section.
+///
+/// Element sections are only supported for modules.
+///
+/// # Example
+///
+/// ```
+/// use std::borrow::Cow;
+/// use wasm_encoder::{
+///     Elements, ElementSection, Module, TableSection, TableType,
+///     RefType, ConstExpr
+/// };
+///
+/// let mut tables = TableSection::new();
+/// tables.table(TableType {
+///     element_type: RefType::FUNCREF,
+///     minimum: 128,
+///     maximum: None,
+///     table64: false,
+///     shared: false,
+/// });
+///
+/// let mut elements = ElementSection::new();
+/// let table_index = 0;
+/// let offset = ConstExpr::i32_const(42);
+/// let functions = Elements::Functions(Cow::Borrowed(&[
+///     // Function indices...
+/// ]));
+/// elements.active(Some(table_index), &offset, functions);
+///
+/// let mut module = Module::new();
+/// module
+///     .section(&tables)
+///     .section(&elements);
+///
+/// let wasm_bytes = module.finish();
+/// ```
+#[derive(Clone, Default, Debug)]
+pub struct ElementSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+/// A sequence of elements in a segment in the element section.
+#[derive(Clone, Debug)]
+pub enum Elements<'a> {
+    /// A sequences of references to functions by their indices.
+    Functions(Cow<'a, [u32]>),
+    /// A sequence of reference expressions.
+    Expressions(RefType, Cow<'a, [ConstExpr]>),
+}
+
+/// An element segment's mode.
+#[derive(Clone, Debug)]
+pub enum ElementMode<'a> {
+    /// A passive element segment.
+    ///
+    /// Passive segments are part of the bulk memory proposal.
+    Passive,
+    /// A declared element segment.
+    ///
+    /// Declared segments are part of the bulk memory proposal.
+    Declared,
+    /// An active element segment.
+    Active {
+        /// The table index.
+        ///
+        /// `Active` element specifying a `None` table forces the MVP encoding and refers to the
+        /// 0th table holding `funcref`s. Non-`None` tables use the encoding introduced with the
+        /// bulk memory proposal and can refer to tables with any valid reference type.
+        table: Option<u32>,
+        /// The offset within the table to place this segment.
+        offset: &'a ConstExpr,
+    },
+}
+
+/// An element segment in the element section.
+#[derive(Clone, Debug)]
+pub struct ElementSegment<'a> {
+    /// The element segment's mode.
+    pub mode: ElementMode<'a>,
+    /// This segment's elements.
+    pub elements: Elements<'a>,
+}
+
+impl ElementSection {
+    /// Create a new element section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of element segments in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define an element segment.
+    pub fn segment<'a>(&mut self, segment: ElementSegment<'a>) -> &mut Self {
+        let expr_bit = match segment.elements {
+            Elements::Expressions(..) => 0b100u32,
+            Elements::Functions(_) => 0b000u32,
+        };
+        let mut encode_type = false;
+        match &segment.mode {
+            ElementMode::Passive => {
+                (0x01 | expr_bit).encode(&mut self.bytes);
+                encode_type = true;
+            }
+            ElementMode::Active { table, offset } => {
+                match (table, &segment.elements) {
+                    // If the `table` is not specified then the 0x00 encoding
+                    // can be used with either function indices or expressions
+                    // that have a `funcref` type.
+                    (None, Elements::Functions(_) | Elements::Expressions(RefType::FUNCREF, _)) => {
+                        (/* 0x00 | */expr_bit).encode(&mut self.bytes);
+                    }
+
+                    // ... otherwise fall through for all other expressions here
+                    // with table 0 or an explicitly specified table to the 0x02
+                    // encoding.
+                    (None, Elements::Expressions(..)) | (Some(_), _) => {
+                        (0x02 | expr_bit).encode(&mut self.bytes);
+                        table.unwrap_or(0).encode(&mut self.bytes);
+                        encode_type = true;
+                    }
+                }
+                offset.encode(&mut self.bytes);
+            }
+            ElementMode::Declared => {
+                (0x03 | expr_bit).encode(&mut self.bytes);
+                encode_type = true;
+            }
+        }
+
+        match segment.elements {
+            Elements::Functions(fs) => {
+                if encode_type {
+                    // elemkind == funcref
+                    self.bytes.push(0x00);
+                }
+                fs.encode(&mut self.bytes);
+            }
+            Elements::Expressions(ty, e) => {
+                if encode_type {
+                    ty.encode(&mut self.bytes);
+                }
+                e.len().encode(&mut self.bytes);
+                for expr in e.iter() {
+                    expr.encode(&mut self.bytes);
+                }
+            }
+        }
+
+        self.num_added += 1;
+        self
+    }
+
+    /// Define an active element segment.
+    ///
+    /// `Active` element specifying a `None` table forces the MVP encoding and refers to the 0th
+    /// table holding `funcref`s. Non-`None` tables use the encoding introduced with the bulk
+    /// memory proposal and can refer to tables with any valid reference type.
+    pub fn active(
+        &mut self,
+        table_index: Option<u32>,
+        offset: &ConstExpr,
+        elements: Elements<'_>,
+    ) -> &mut Self {
+        self.segment(ElementSegment {
+            mode: ElementMode::Active {
+                table: table_index,
+                offset,
+            },
+            elements,
+        })
+    }
+
+    /// Encode a passive element segment.
+    ///
+    /// Passive segments are part of the bulk memory proposal.
+    pub fn passive<'a>(&mut self, elements: Elements<'a>) -> &mut Self {
+        self.segment(ElementSegment {
+            mode: ElementMode::Passive,
+            elements,
+        })
+    }
+
+    /// Encode a declared element segment.
+    ///
+    /// Declared segments are part of the bulk memory proposal.
+    pub fn declared<'a>(&mut self, elements: Elements<'a>) -> &mut Self {
+        self.segment(ElementSegment {
+            mode: ElementMode::Declared,
+            elements,
+        })
+    }
+
+    /// Copy a raw, already-encoded element segment into this elements section.
+    pub fn raw(&mut self, raw_bytes: &[u8]) -> &mut Self {
+        self.bytes.extend_from_slice(raw_bytes);
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for ElementSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl Section for ElementSection {
+    fn id(&self) -> u8 {
+        SectionId::Element.into()
+    }
+}

vendor/wasm-encoder/src/core/exports.rs

@@ -0,0 +1,86 @@
+use super::{
+    CORE_FUNCTION_SORT, CORE_GLOBAL_SORT, CORE_MEMORY_SORT, CORE_TABLE_SORT, CORE_TAG_SORT,
+};
+use crate::{Encode, Section, SectionId, encode_section};
+use alloc::vec::Vec;
+
+/// Represents the kind of an export from a WebAssembly module.
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
+#[repr(u8)]
+pub enum ExportKind {
+    /// The export is a function.
+    Func = CORE_FUNCTION_SORT,
+    /// The export is a table.
+    Table = CORE_TABLE_SORT,
+    /// The export is a memory.
+    Memory = CORE_MEMORY_SORT,
+    /// The export is a global.
+    Global = CORE_GLOBAL_SORT,
+    /// The export is a tag.
+    Tag = CORE_TAG_SORT,
+}
+
+impl Encode for ExportKind {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        sink.push(*self as u8);
+    }
+}
+
+/// An encoder for the export section of WebAssembly module.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{Module, ExportSection, ExportKind};
+///
+/// let mut exports = ExportSection::new();
+/// exports.export("foo", ExportKind::Func, 0);
+///
+/// let mut module = Module::new();
+/// module.section(&exports);
+///
+/// let bytes = module.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct ExportSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl ExportSection {
+    /// Create a new export section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of exports in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define an export in the export section.
+    pub fn export(&mut self, name: &str, kind: ExportKind, index: u32) -> &mut Self {
+        name.encode(&mut self.bytes);
+        kind.encode(&mut self.bytes);
+        index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for ExportSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl Section for ExportSection {
+    fn id(&self) -> u8 {
+        SectionId::Export.into()
+    }
+}

vendor/wasm-encoder/src/core/functions.rs

@@ -0,0 +1,64 @@
+use crate::{Encode, Section, SectionId, encode_section};
+use alloc::vec::Vec;
+
+/// An encoder for the function section of WebAssembly modules.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{Module, FunctionSection, ValType};
+///
+/// let mut functions = FunctionSection::new();
+/// let type_index = 0;
+/// functions.function(type_index);
+///
+/// let mut module = Module::new();
+/// module.section(&functions);
+///
+/// // Note: this will generate an invalid module because we didn't generate a
+/// // code section containing the function body. See the documentation for
+/// // `CodeSection` for details.
+///
+/// let bytes = module.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct FunctionSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl FunctionSection {
+    /// Construct a new module function section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of functions in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define a function in a module's function section.
+    pub fn function(&mut self, type_index: u32) -> &mut Self {
+        type_index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for FunctionSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl Section for FunctionSection {
+    fn id(&self) -> u8 {
+        SectionId::Function.into()
+    }
+}

vendor/wasm-encoder/src/core/globals.rs

@@ -0,0 +1,101 @@
+use crate::{ConstExpr, Encode, Section, SectionId, ValType, encode_section};
+use alloc::vec::Vec;
+
+/// An encoder for the global section.
+///
+/// Global sections are only supported for modules.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{ConstExpr, Module, GlobalSection, GlobalType, Instruction, ValType};
+///
+/// let mut globals = GlobalSection::new();
+/// globals.global(
+///     GlobalType {
+///         val_type: ValType::I32,
+///         mutable: false,
+///         shared: false,
+///     },
+///     &ConstExpr::i32_const(42),
+/// );
+///
+/// let mut module = Module::new();
+/// module.section(&globals);
+///
+/// let wasm_bytes = module.finish();
+/// ```
+#[derive(Clone, Default, Debug)]
+pub struct GlobalSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl GlobalSection {
+    /// Create a new global section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of globals in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define a global.
+    pub fn global(&mut self, global_type: GlobalType, init_expr: &ConstExpr) -> &mut Self {
+        global_type.encode(&mut self.bytes);
+        init_expr.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Add a raw byte slice into this code section as a global.
+    pub fn raw(&mut self, data: &[u8]) -> &mut Self {
+        self.bytes.extend(data);
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for GlobalSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl Section for GlobalSection {
+    fn id(&self) -> u8 {
+        SectionId::Global.into()
+    }
+}
+
+/// A global's type.
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
+pub struct GlobalType {
+    /// This global's value type.
+    pub val_type: ValType,
+    /// Whether this global is mutable or not.
+    pub mutable: bool,
+    /// Whether this global is shared or not.
+    pub shared: bool,
+}
+
+impl Encode for GlobalType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.val_type.encode(sink);
+        let mut flag = 0;
+        if self.mutable {
+            flag |= 0b01;
+        }
+        if self.shared {
+            flag |= 0b10;
+        }
+        sink.push(flag);
+    }
+}

vendor/wasm-encoder/src/core/imports.rs

@@ -0,0 +1,230 @@
+use crate::{
+    CORE_FUNCTION_EXACT_SORT, CORE_FUNCTION_SORT, CORE_GLOBAL_SORT, CORE_MEMORY_SORT,
+    CORE_TABLE_SORT, CORE_TAG_SORT, Encode, GlobalType, MemoryType, Section, SectionId, TableType,
+    TagType, encode_section,
+};
+use alloc::borrow::Cow;
+use alloc::vec::Vec;
+
+/// The type of an entity.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum EntityType {
+    /// A function type.
+    ///
+    /// The value is an index into the types section.
+    Function(u32),
+    /// A table type.
+    Table(TableType),
+    /// A memory type.
+    Memory(MemoryType),
+    /// A global type.
+    Global(GlobalType),
+    /// A tag type.
+    ///
+    /// This variant is used with the exception handling proposal.
+    Tag(TagType),
+    /// A function exact type.
+    ///
+    /// The value is an index into the types section.
+    FunctionExact(u32),
+}
+
+impl Encode for EntityType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            Self::Function(f) => {
+                sink.push(CORE_FUNCTION_SORT);
+                f.encode(sink);
+            }
+            Self::FunctionExact(f) => {
+                sink.push(CORE_FUNCTION_EXACT_SORT);
+                f.encode(sink);
+            }
+            Self::Table(t) => {
+                sink.push(CORE_TABLE_SORT);
+                t.encode(sink);
+            }
+            Self::Memory(t) => {
+                sink.push(CORE_MEMORY_SORT);
+                t.encode(sink);
+            }
+            Self::Global(t) => {
+                sink.push(CORE_GLOBAL_SORT);
+                t.encode(sink);
+            }
+            Self::Tag(t) => {
+                sink.push(CORE_TAG_SORT);
+                t.encode(sink);
+            }
+        }
+    }
+}
+
+impl From<TableType> for EntityType {
+    fn from(t: TableType) -> Self {
+        Self::Table(t)
+    }
+}
+
+impl From<MemoryType> for EntityType {
+    fn from(t: MemoryType) -> Self {
+        Self::Memory(t)
+    }
+}
+
+impl From<GlobalType> for EntityType {
+    fn from(t: GlobalType) -> Self {
+        Self::Global(t)
+    }
+}
+
+impl From<TagType> for EntityType {
+    fn from(t: TagType) -> Self {
+        Self::Tag(t)
+    }
+}
+
+/// An import item to be used with [`Imports::Single`].
+#[derive(Clone, Debug)]
+pub struct Import<'a> {
+    /// The import's module name.
+    pub module: &'a str,
+    /// The import's item name.
+    pub name: &'a str,
+    /// The import's time.
+    pub ty: EntityType,
+}
+
+/// An import item to be used with [`Imports::Compact1`].
+#[derive(Clone, Debug)]
+pub struct ImportCompact<'a> {
+    /// The import's item name.
+    pub name: &'a str,
+    /// The import's type.
+    pub ty: EntityType,
+}
+
+/// A single entry in the import section of a WebAssembly module, possibly containing multiple imports.
+#[derive(Clone, Debug)]
+pub enum Imports<'a> {
+    /// A single import item.
+    Single(Import<'a>),
+    /// A group of imports with a common module name.
+    Compact1 {
+        /// The common module name.
+        module: &'a str,
+        /// The individual import items (name/type).
+        items: Cow<'a, [ImportCompact<'a>]>,
+    },
+    /// A group of imports with a common module name and type.
+    Compact2 {
+        /// The common module name.
+        module: &'a str,
+        /// The common import type.
+        ty: EntityType,
+        /// The individual import item names.
+        names: Cow<'a, [&'a str]>,
+    },
+}
+
+/// An encoder for the import section of WebAssembly modules.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{MemoryType, Module, ImportSection};
+///
+/// let mut imports = ImportSection::new();
+/// imports.import(
+///     "env",
+///     "memory",
+///     MemoryType {
+///         minimum: 1,
+///         maximum: None,
+///         memory64: false,
+///         shared: false,
+///         page_size_log2: None,
+///     }
+/// );
+///
+/// let mut module = Module::new();
+/// module.section(&imports);
+///
+/// let bytes = module.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct ImportSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl ImportSection {
+    /// Create a new import section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of imports in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define imports in the import section.
+    pub fn imports<'a>(&mut self, imports: Imports<'a>) -> &mut Self {
+        match imports {
+            Imports::Single(import) => {
+                import.module.encode(&mut self.bytes);
+                import.name.encode(&mut self.bytes);
+                import.ty.encode(&mut self.bytes);
+            }
+            Imports::Compact1 { module, items } => {
+                module.encode(&mut self.bytes);
+                self.bytes.push(0x00); // empty name
+                self.bytes.push(0x7F);
+                items.len().encode(&mut self.bytes);
+                for item in items.iter() {
+                    item.name.encode(&mut self.bytes);
+                    item.ty.encode(&mut self.bytes);
+                }
+            }
+            Imports::Compact2 { module, ty, names } => {
+                module.encode(&mut self.bytes);
+                self.bytes.push(0x00); // empty name
+                self.bytes.push(0x7E);
+                ty.encode(&mut self.bytes);
+                names.len().encode(&mut self.bytes);
+                for item in names.iter() {
+                    item.encode(&mut self.bytes);
+                }
+            }
+        }
+        self.num_added += 1;
+        self
+    }
+
+    /// Define an import in the import section.
+    pub fn import(&mut self, module: &str, name: &str, ty: impl Into<EntityType>) -> &mut Self {
+        self.imports(Imports::Single(Import {
+            module,
+            name,
+            ty: ty.into(),
+        }))
+    }
+}
+
+impl Encode for ImportSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl Section for ImportSection {
+    fn id(&self) -> u8 {
+        SectionId::Import.into()
+    }
+}

vendor/wasm-encoder/src/core/linking.rs

@@ -0,0 +1,264 @@
+use crate::{CustomSection, Encode, Section, SectionId, encode_section};
+use alloc::borrow::Cow;
+use alloc::vec;
+use alloc::vec::Vec;
+
+const VERSION: u32 = 2;
+
+/// An encoder for the [linking custom
+/// section](https://github.com/WebAssembly/tool-conventions/blob/master/Linking.md#linking-metadata-section).
+///
+/// This section is a non-standard convention that is supported by the LLVM
+/// toolchain. It, along with associated "reloc.*" custom sections, allows you
+/// to treat a Wasm module as a low-level object file that can be linked with
+/// other Wasm object files to produce a final, complete Wasm module.
+///
+/// The linking section must come before the reloc sections.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{LinkingSection, Module, SymbolTable};
+///
+/// // Create a new linking section.
+/// let mut linking = LinkingSection::new();
+///
+/// // Define a symbol table.
+/// let mut sym_tab = SymbolTable::new();
+///
+/// // Define a function symbol in the symbol table.
+/// let flags = SymbolTable::WASM_SYM_BINDING_LOCAL | SymbolTable::WASM_SYM_EXPORTED;
+/// let func_index = 42;
+/// let sym_name = "my_exported_func";
+/// sym_tab.function(flags, func_index, Some(sym_name));
+///
+/// // Add the symbol table to our linking section.
+/// linking.symbol_table(&sym_tab);
+///
+/// // Add the linking section to a new Wasm module and get the encoded bytes.
+/// let mut module = Module::new();
+/// module.section(&linking);
+/// let wasm_bytes = module.finish();
+/// ```
+#[derive(Clone, Debug)]
+pub struct LinkingSection {
+    bytes: Vec<u8>,
+}
+
+impl LinkingSection {
+    /// Construct a new encoder for the linking custom section.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    // TODO: `fn segment_info` for the `WASM_SEGMENT_INFO` linking subsection.
+
+    // TODO: `fn init_funcs` for the `WASM_INIT_FUNCS` linking subsection.
+
+    // TODO: `fn comdat_info` for the `WASM_COMDAT_INFO` linking subsection.
+
+    /// Add a symbol table subsection.
+    pub fn symbol_table(&mut self, symbol_table: &SymbolTable) -> &mut Self {
+        symbol_table.encode(&mut self.bytes);
+        self
+    }
+}
+
+impl Default for LinkingSection {
+    fn default() -> Self {
+        let mut bytes = Vec::new();
+        VERSION.encode(&mut bytes);
+        Self { bytes }
+    }
+}
+
+impl Encode for LinkingSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        CustomSection {
+            name: "linking".into(),
+            data: Cow::Borrowed(&self.bytes),
+        }
+        .encode(sink);
+    }
+}
+
+impl Section for LinkingSection {
+    fn id(&self) -> u8 {
+        SectionId::Custom.into()
+    }
+}
+
+#[allow(unused)]
+const WASM_SEGMENT_INFO: u8 = 5;
+#[allow(unused)]
+const WASM_INIT_FUNCS: u8 = 6;
+#[allow(unused)]
+const WASM_COMDAT_INFO: u8 = 7;
+const WASM_SYMBOL_TABLE: u8 = 8;
+
+/// A subsection of the [linking custom section][crate::LinkingSection] that
+/// provides extra information about the symbols present in this Wasm object
+/// file.
+#[derive(Clone, Debug, Default)]
+pub struct SymbolTable {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+const SYMTAB_FUNCTION: u32 = 0;
+const SYMTAB_DATA: u32 = 1;
+const SYMTAB_GLOBAL: u32 = 2;
+#[allow(unused)]
+const SYMTAB_SECTION: u32 = 3;
+#[allow(unused)]
+const SYMTAB_TAG: u32 = 4;
+const SYMTAB_TABLE: u32 = 5;
+
+impl SymbolTable {
+    /// Construct a new symbol table subsection encoder.
+    pub fn new() -> Self {
+        SymbolTable {
+            bytes: vec![],
+            num_added: 0,
+        }
+    }
+
+    /// Define a function symbol in this symbol table.
+    ///
+    /// The `name` must be omitted if `index` references an imported table and
+    /// the `WASM_SYM_EXPLICIT_NAME` flag is not set.
+    pub fn function(&mut self, flags: u32, index: u32, name: Option<&str>) -> &mut Self {
+        SYMTAB_FUNCTION.encode(&mut self.bytes);
+        flags.encode(&mut self.bytes);
+        index.encode(&mut self.bytes);
+        if let Some(name) = name {
+            name.encode(&mut self.bytes);
+        }
+        self.num_added += 1;
+        self
+    }
+
+    /// Define a global symbol in this symbol table.
+    ///
+    /// The `name` must be omitted if `index` references an imported table and
+    /// the `WASM_SYM_EXPLICIT_NAME` flag is not set.
+    pub fn global(&mut self, flags: u32, index: u32, name: Option<&str>) -> &mut Self {
+        SYMTAB_GLOBAL.encode(&mut self.bytes);
+        flags.encode(&mut self.bytes);
+        index.encode(&mut self.bytes);
+        if let Some(name) = name {
+            name.encode(&mut self.bytes);
+        }
+        self.num_added += 1;
+        self
+    }
+
+    // TODO: tags
+
+    /// Define a table symbol in this symbol table.
+    ///
+    /// The `name` must be omitted if `index` references an imported table and
+    /// the `WASM_SYM_EXPLICIT_NAME` flag is not set.
+    pub fn table(&mut self, flags: u32, index: u32, name: Option<&str>) -> &mut Self {
+        SYMTAB_TABLE.encode(&mut self.bytes);
+        flags.encode(&mut self.bytes);
+        index.encode(&mut self.bytes);
+        if let Some(name) = name {
+            name.encode(&mut self.bytes);
+        }
+        self.num_added += 1;
+        self
+    }
+
+    /// Add a data symbol to this symbol table.
+    pub fn data(
+        &mut self,
+        flags: u32,
+        name: &str,
+        definition: Option<DataSymbolDefinition>,
+    ) -> &mut Self {
+        SYMTAB_DATA.encode(&mut self.bytes);
+        flags.encode(&mut self.bytes);
+        name.encode(&mut self.bytes);
+        if let Some(def) = definition {
+            def.index.encode(&mut self.bytes);
+            def.offset.encode(&mut self.bytes);
+            def.size.encode(&mut self.bytes);
+        }
+        self.num_added += 1;
+        self
+    }
+
+    // TODO: sections
+
+    /// This is a weak symbol.
+    ///
+    /// This flag is mutually exclusive with `WASM_SYM_BINDING_LOCAL`.
+    ///
+    /// When linking multiple modules defining the same symbol, all weak
+    /// definitions are discarded if any strong definitions exist; then if
+    /// multiple weak definitions exist all but one (unspecified) are discarded;
+    /// and finally it is an error if more than one definition remains.
+    pub const WASM_SYM_BINDING_WEAK: u32 = 0x1;
+
+    /// This is a local symbol.
+    ///
+    /// This flag is mutually exclusive with `WASM_SYM_BINDING_WEAK`.
+    ///
+    /// Local symbols are not to be exported, or linked to other
+    /// modules/sections. The names of all non-local symbols must be unique, but
+    /// the names of local symbols are not considered for uniqueness. A local
+    /// function or global symbol cannot reference an import.
+    pub const WASM_SYM_BINDING_LOCAL: u32 = 0x02;
+
+    /// This is a hidden symbol.
+    ///
+    /// Hidden symbols are not to be exported when performing the final link,
+    /// but may be linked to other modules.
+    pub const WASM_SYM_VISIBILITY_HIDDEN: u32 = 0x04;
+
+    /// This symbol is not defined.
+    ///
+    /// For non-data symbols, this must match whether the symbol is an import or
+    /// is defined; for data symbols, determines whether a segment is specified.
+    pub const WASM_SYM_UNDEFINED: u32 = 0x10;
+
+    /// This symbol is intended to be exported from the wasm module to the host
+    /// environment.
+    ///
+    /// This differs from the visibility flags in that it effects the static
+    /// linker.
+    pub const WASM_SYM_EXPORTED: u32 = 0x20;
+
+    /// This symbol uses an explicit symbol name, rather than reusing the name
+    /// from a wasm import.
+    ///
+    /// This allows it to remap imports from foreign WebAssembly modules into
+    /// local symbols with different names.
+    pub const WASM_SYM_EXPLICIT_NAME: u32 = 0x40;
+
+    /// This symbol is intended to be included in the linker output, regardless
+    /// of whether it is used by the program.
+    pub const WASM_SYM_NO_STRIP: u32 = 0x80;
+}
+
+impl Encode for SymbolTable {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        sink.push(WASM_SYMBOL_TABLE);
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+/// The definition of a data symbol within a symbol table.
+#[derive(Clone, Debug)]
+pub struct DataSymbolDefinition {
+    /// The index of the data segment that this symbol is in.
+    pub index: u32,
+    /// The offset of this symbol within its segment.
+    pub offset: u32,
+    /// The byte size (which can be zero) of this data symbol.
+    ///
+    /// Note that `offset + size` must be less than or equal to the segment's
+    /// size.
+    pub size: u32,
+}

vendor/wasm-encoder/src/core/memories.rs

@@ -0,0 +1,116 @@
+use crate::{Encode, Section, SectionId, encode_section};
+use alloc::vec::Vec;
+
+/// An encoder for the memory section.
+///
+/// Memory sections are only supported for modules.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{Module, MemorySection, MemoryType};
+///
+/// let mut memories = MemorySection::new();
+/// memories.memory(MemoryType {
+///     minimum: 1,
+///     maximum: None,
+///     memory64: false,
+///     shared: false,
+///     page_size_log2: None,
+/// });
+///
+/// let mut module = Module::new();
+/// module.section(&memories);
+///
+/// let wasm_bytes = module.finish();
+/// ```
+#[derive(Clone, Default, Debug)]
+pub struct MemorySection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl MemorySection {
+    /// Create a new memory section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of memories in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define a memory.
+    pub fn memory(&mut self, memory_type: MemoryType) -> &mut Self {
+        memory_type.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for MemorySection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl Section for MemorySection {
+    fn id(&self) -> u8 {
+        SectionId::Memory.into()
+    }
+}
+
+/// A memory's type.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct MemoryType {
+    /// Minimum size, in pages, of this memory
+    pub minimum: u64,
+    /// Maximum size, in pages, of this memory
+    pub maximum: Option<u64>,
+    /// Whether or not this is a 64-bit memory.
+    pub memory64: bool,
+    /// Whether or not this memory is shared.
+    pub shared: bool,
+    /// The log base 2 of a custom page size for this memory.
+    ///
+    /// The default page size for Wasm memories is 64KiB, i.e. 2<sup>16</sup> or
+    /// `65536`.
+    ///
+    /// After the introduction of [the custom-page-sizes
+    /// proposal](https://github.com/WebAssembly/custom-page-sizes), Wasm can
+    /// customize the page size. It must be a power of two that is less than or
+    /// equal to 64KiB. Attempting to encode an invalid page size may panic.
+    pub page_size_log2: Option<u32>,
+}
+
+impl Encode for MemoryType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        let mut flags = 0;
+        if self.maximum.is_some() {
+            flags |= 0b0001;
+        }
+        if self.shared {
+            flags |= 0b0010;
+        }
+        if self.memory64 {
+            flags |= 0b0100;
+        }
+        if self.page_size_log2.is_some() {
+            flags |= 0b1000;
+        }
+        sink.push(flags);
+        self.minimum.encode(sink);
+        if let Some(max) = self.maximum {
+            max.encode(sink);
+        }
+        if let Some(p) = self.page_size_log2 {
+            p.encode(sink);
+        }
+    }
+}

vendor/wasm-encoder/src/core/names.rs

@@ -0,0 +1,305 @@
+use crate::{CustomSection, Encode, Section, SectionId, encoding_size};
+use alloc::borrow::Cow;
+use alloc::vec;
+use alloc::vec::Vec;
+
+/// An encoder for the custom `name` section.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{Module, NameSection, NameMap};
+///
+/// let mut names = NameSection::new();
+/// names.module("the module name");
+///
+/// let mut function_names = NameMap::new();
+/// function_names.append(0, "name of function 0");
+/// function_names.append(1, "a better function");
+/// function_names.append(3, "the best function");
+/// names.functions(&function_names);
+///
+/// let mut module = Module::new();
+/// module.section(&names);
+///
+/// let wasm_bytes = module.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct NameSection {
+    bytes: Vec<u8>,
+}
+
+enum Subsection {
+    // Currently specified in the wasm spec's appendix
+    Module = 0,
+    Function = 1,
+    Local = 2,
+
+    // specified as part of the extended name section proposal
+    //
+    // https://github.com/WebAssembly/extended-name-section/blob/main/proposals/extended-name-section/Overview.md
+    Label = 3,
+    Type = 4,
+    Table = 5,
+    Memory = 6,
+    Global = 7,
+    Element = 8,
+    Data = 9,
+
+    // https://github.com/WebAssembly/gc/issues/193
+    Field = 10,
+
+    // https://github.com/WebAssembly/exception-handling/pull/213
+    Tag = 11,
+}
+
+impl NameSection {
+    /// Creates a new blank `name` custom section.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Appends a module name subsection to this section.
+    ///
+    /// This will indicate that the name of the entire module should be the
+    /// `name` specified. Note that this should be encoded first before other
+    /// subsections.
+    pub fn module(&mut self, name: &str) {
+        let len = encoding_size(u32::try_from(name.len()).unwrap());
+        self.subsection_header(Subsection::Module, len + name.len());
+        name.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of all functions in this wasm module.
+    ///
+    /// Function names are declared in the `names` map provided where the index
+    /// in the map corresponds to the wasm index of the function. This section
+    /// should come after the module name subsection (if present) and before the
+    /// locals subsection (if present).
+    pub fn functions(&mut self, names: &NameMap) {
+        self.subsection_header(Subsection::Function, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of locals within functions in this
+    /// wasm module.
+    ///
+    /// This section should come after the function name subsection (if present)
+    /// and before the labels subsection (if present).
+    pub fn locals(&mut self, names: &IndirectNameMap) {
+        self.subsection_header(Subsection::Local, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of labels within functions in this
+    /// wasm module.
+    ///
+    /// This section should come after the local name subsection (if present)
+    /// and before the type subsection (if present).
+    pub fn labels(&mut self, names: &IndirectNameMap) {
+        self.subsection_header(Subsection::Label, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of all types in this wasm module.
+    ///
+    /// This section should come after the label name subsection (if present)
+    /// and before the table subsection (if present).
+    pub fn types(&mut self, names: &NameMap) {
+        self.subsection_header(Subsection::Type, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of all tables in this wasm module.
+    ///
+    /// This section should come after the type name subsection (if present)
+    /// and before the memory subsection (if present).
+    pub fn tables(&mut self, names: &NameMap) {
+        self.subsection_header(Subsection::Table, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of all memories in this wasm module.
+    ///
+    /// This section should come after the table name subsection (if present)
+    /// and before the global subsection (if present).
+    pub fn memories(&mut self, names: &NameMap) {
+        self.subsection_header(Subsection::Memory, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of all globals in this wasm module.
+    ///
+    /// This section should come after the memory name subsection (if present)
+    /// and before the element subsection (if present).
+    pub fn globals(&mut self, names: &NameMap) {
+        self.subsection_header(Subsection::Global, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of all elements in this wasm module.
+    ///
+    /// This section should come after the global name subsection (if present)
+    /// and before the data subsection (if present).
+    pub fn elements(&mut self, names: &NameMap) {
+        self.subsection_header(Subsection::Element, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of all data in this wasm module.
+    ///
+    /// This section should come after the element name subsection (if present)
+    /// and before the field subsection (if present).
+    pub fn data(&mut self, names: &NameMap) {
+        self.subsection_header(Subsection::Data, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of all tags in this wasm module.
+    ///
+    /// This section should come after the data name subsection (if present).
+    pub fn tag(&mut self, names: &NameMap) {
+        self.subsection_header(Subsection::Tag, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of fields within types in this
+    /// wasm module.
+    ///
+    /// This section should come after the data name subsection (if present)
+    /// and before the tag subsection (if present).
+    pub fn fields(&mut self, names: &IndirectNameMap) {
+        self.subsection_header(Subsection::Field, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a subsection for the names of all tags in this wasm module.
+    ///
+    /// This section should come after the field name subsection (if present).
+    pub fn tags(&mut self, names: &NameMap) {
+        self.subsection_header(Subsection::Tag, names.size());
+        names.encode(&mut self.bytes);
+    }
+
+    /// Appends a raw subsection with the given id and data.
+    pub fn raw(&mut self, id: u8, data: &[u8]) {
+        self.bytes.push(id);
+        data.encode(&mut self.bytes);
+    }
+
+    fn subsection_header(&mut self, id: Subsection, len: usize) {
+        self.bytes.push(id as u8);
+        len.encode(&mut self.bytes);
+    }
+
+    /// View the encoded section as a CustomSection.
+    pub fn as_custom<'a>(&'a self) -> CustomSection<'a> {
+        CustomSection {
+            name: "name".into(),
+            data: Cow::Borrowed(&self.bytes),
+        }
+    }
+}
+
+impl Encode for NameSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.as_custom().encode(sink);
+    }
+}
+
+impl Section for NameSection {
+    fn id(&self) -> u8 {
+        SectionId::Custom.into()
+    }
+}
+
+/// A map used to name items in a wasm module, organized by naming each
+/// individual index.
+///
+/// This is used in conjunction with [`NameSection::functions`] and simlar
+/// methods.
+#[derive(Clone, Debug, Default)]
+pub struct NameMap {
+    bytes: Vec<u8>,
+    count: u32,
+}
+
+impl NameMap {
+    /// Creates a new empty `NameMap`.
+    pub fn new() -> NameMap {
+        NameMap {
+            bytes: vec![],
+            count: 0,
+        }
+    }
+
+    /// Adds a an entry where the item at `idx` has the `name` specified.
+    ///
+    /// Note that indices should be appended in ascending order of the index
+    /// value. Each index may only be named once, but not all indices must be
+    /// named (e.g. `0 foo; 1 bar; 7 qux` is valid but `0 foo; 0 bar` is not).
+    /// Names do not have to be unique (e.g. `0 foo; 1 foo; 2 foo` is valid).
+    pub fn append(&mut self, idx: u32, name: &str) {
+        idx.encode(&mut self.bytes);
+        name.encode(&mut self.bytes);
+        self.count += 1;
+    }
+
+    pub(crate) fn size(&self) -> usize {
+        encoding_size(self.count) + self.bytes.len()
+    }
+
+    /// Returns whether no names have been added to this map.
+    pub fn is_empty(&self) -> bool {
+        self.count == 0
+    }
+}
+
+impl Encode for NameMap {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.count.encode(sink);
+        sink.extend(&self.bytes);
+    }
+}
+
+/// A map used to describe names with two levels of indirection, as opposed to a
+/// [`NameMap`] which has one level of indirection.
+///
+/// This naming map is used with [`NameSection::locals`], for example.
+#[derive(Clone, Debug, Default)]
+pub struct IndirectNameMap {
+    bytes: Vec<u8>,
+    count: u32,
+}
+
+impl IndirectNameMap {
+    /// Creates a new empty name map.
+    pub fn new() -> IndirectNameMap {
+        IndirectNameMap {
+            bytes: vec![],
+            count: 0,
+        }
+    }
+
+    /// Adds a new entry where the item at `idx` has sub-items named within
+    /// `names` as specified.
+    ///
+    /// For example if this is describing local names then `idx` is a function
+    /// index where the indexes within `names` are local indices.
+    pub fn append(&mut self, idx: u32, names: &NameMap) {
+        idx.encode(&mut self.bytes);
+        names.encode(&mut self.bytes);
+        self.count += 1;
+    }
+
+    fn size(&self) -> usize {
+        encoding_size(self.count) + self.bytes.len()
+    }
+}
+
+impl Encode for IndirectNameMap {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.count.encode(sink);
+        sink.extend(&self.bytes);
+    }
+}

vendor/wasm-encoder/src/core/producers.rs

@@ -0,0 +1,181 @@
+use crate::{CustomSection, Encode, Section, SectionId};
+use alloc::borrow::Cow;
+use alloc::vec::Vec;
+
+/// An encoder for the [producers custom
+/// section](https://github.com/WebAssembly/tool-conventions/blob/main/ProducersSection.md).
+///
+/// This section is a non-standard convention that is supported by many toolchains.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{ProducersSection, ProducersField, Module};
+///
+/// // Create a new producers section.
+/// let mut field = ProducersField::new();
+/// field.value("clang", "14.0.4");
+/// field.value("rustc", "1.66.1 (90743e729 2023-01-10)");
+/// let mut producers = ProducersSection::new();
+/// producers.field("processed-by", &field);
+///
+/// // Add the producers section to a new Wasm module and get the encoded bytes.
+/// let mut module = Module::new();
+/// module.section(&producers);
+/// let wasm_bytes = module.finish();
+/// ```
+#[derive(Clone, Debug)]
+pub struct ProducersSection {
+    bytes: Vec<u8>,
+    num_fields: u32,
+}
+
+impl ProducersSection {
+    /// Construct an empty encoder for the producers custom section.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Add a field to the section. The spec recommends names for this section
+    /// are "language", "processed-by", and "sdk".  Each field in section must
+    /// have a unique name.
+    pub fn field(&mut self, name: &str, values: &ProducersField) -> &mut Self {
+        name.encode(&mut self.bytes);
+        values.encode(&mut self.bytes);
+        self.num_fields += 1;
+        self
+    }
+}
+
+impl Default for ProducersSection {
+    fn default() -> Self {
+        Self {
+            bytes: Vec::new(),
+            num_fields: 0,
+        }
+    }
+}
+
+impl Encode for ProducersSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        let mut data = Vec::new();
+        self.num_fields.encode(&mut data);
+        data.extend(&self.bytes);
+
+        CustomSection {
+            name: "producers".into(),
+            data: Cow::Borrowed(&data),
+        }
+        .encode(sink);
+    }
+}
+
+impl Section for ProducersSection {
+    fn id(&self) -> u8 {
+        SectionId::Custom.into()
+    }
+}
+
+/// The value of a field in the producers custom section
+#[derive(Clone, Debug)]
+pub struct ProducersField {
+    bytes: Vec<u8>,
+    num_values: u32,
+}
+
+impl ProducersField {
+    /// Construct an empty encoder for a producers field value
+    pub fn new() -> Self {
+        ProducersField::default()
+    }
+
+    /// Add a value to the field encoder. Each value in a field must have a
+    /// unique name. If there is no sensible value for `version`, use the
+    /// empty string.
+    pub fn value(&mut self, name: &str, version: &str) -> &mut Self {
+        name.encode(&mut self.bytes);
+        version.encode(&mut self.bytes);
+        self.num_values += 1;
+        self
+    }
+}
+
+impl Default for ProducersField {
+    fn default() -> Self {
+        Self {
+            bytes: Vec::new(),
+            num_values: 0,
+        }
+    }
+}
+
+impl Encode for ProducersField {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.num_values.encode(sink);
+        sink.extend(&self.bytes);
+    }
+}
+
+#[cfg(test)]
+mod test {
+    #[test]
+    fn roundtrip_example() {
+        use crate::{Module, ProducersField, ProducersSection};
+        use wasmparser::{KnownCustom, Parser, Payload};
+
+        // Create a new producers section.
+        let mut field = ProducersField::new();
+        field.value("clang", "14.0.4");
+        field.value("rustc", "1.66.1");
+        let mut producers = ProducersSection::new();
+        producers.field("processed-by", &field);
+
+        // Add the producers section to a new Wasm module and get the encoded bytes.
+        let mut module = Module::new();
+        module.section(&producers);
+        let wasm_bytes = module.finish();
+
+        let mut parser = Parser::new(0).parse_all(&wasm_bytes);
+        let payload = parser
+            .next()
+            .expect("parser is not empty")
+            .expect("element is a payload");
+        match payload {
+            Payload::Version { .. } => {}
+            _ => panic!(""),
+        }
+        let payload = parser
+            .next()
+            .expect("parser is not empty")
+            .expect("element is a payload");
+        match payload {
+            Payload::CustomSection(c) => {
+                assert_eq!(c.name(), "producers");
+                let mut section = match c.as_known() {
+                    KnownCustom::Producers(s) => s.into_iter(),
+                    _ => panic!("unknown custom section"),
+                };
+                let field = section
+                    .next()
+                    .expect("section has an element")
+                    .expect("element is a producers field");
+                assert_eq!(field.name, "processed-by");
+                let mut values = field.values.into_iter();
+                let value = values
+                    .next()
+                    .expect("values has an element")
+                    .expect("element is a producers field value");
+                assert_eq!(value.name, "clang");
+                assert_eq!(value.version, "14.0.4");
+
+                let value = values
+                    .next()
+                    .expect("values has another element")
+                    .expect("element is a producers field value");
+                assert_eq!(value.name, "rustc");
+                assert_eq!(value.version, "1.66.1");
+            }
+            _ => panic!("unexpected payload"),
+        }
+    }
+}

vendor/wasm-encoder/src/core/start.rs

@@ -0,0 +1,40 @@
+use crate::{Encode, Section, SectionId, encoding_size};
+use alloc::vec::Vec;
+
+/// An encoder for the start section of WebAssembly modules.
+///
+/// # Example
+///
+/// Note: this doesn't actually define the function at index 0, its type, or its
+/// code body, so the resulting Wasm module will be invalid. See `TypeSection`,
+/// `FunctionSection`, and `CodeSection` for details on how to generate those
+/// things.
+///
+/// ```
+/// use wasm_encoder::{Module, StartSection};
+///
+/// let start = StartSection { function_index: 0 };
+///
+/// let mut module = Module::new();
+/// module.section(&start);
+///
+/// let wasm_bytes = module.finish();
+/// ```
+#[derive(Clone, Copy, Debug)]
+pub struct StartSection {
+    /// The index of the start function.
+    pub function_index: u32,
+}
+
+impl Encode for StartSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encoding_size(self.function_index).encode(sink);
+        self.function_index.encode(sink);
+    }
+}
+
+impl Section for StartSection {
+    fn id(&self) -> u8 {
+        SectionId::Start.into()
+    }
+}

vendor/wasm-encoder/src/core/tables.rs

@@ -0,0 +1,130 @@
+use crate::{ConstExpr, Encode, RefType, Section, SectionId, ValType, encode_section};
+use alloc::vec::Vec;
+
+/// An encoder for the table section.
+///
+/// Table sections are only supported for modules.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{Module, TableSection, TableType, RefType};
+///
+/// let mut tables = TableSection::new();
+/// tables.table(TableType {
+///     element_type: RefType::FUNCREF,
+///     minimum: 128,
+///     maximum: None,
+///     table64: false,
+///     shared: false,
+/// });
+///
+/// let mut module = Module::new();
+/// module.section(&tables);
+///
+/// let wasm_bytes = module.finish();
+/// ```
+#[derive(Clone, Default, Debug)]
+pub struct TableSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl TableSection {
+    /// Construct a new table section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of tables in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define a table.
+    pub fn table(&mut self, table_type: TableType) -> &mut Self {
+        table_type.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Define a table with an explicit initialization expression.
+    ///
+    /// Note that this is part of the function-references proposal.
+    pub fn table_with_init(&mut self, table_type: TableType, init: &ConstExpr) -> &mut Self {
+        self.bytes.push(0x40);
+        self.bytes.push(0x00);
+        table_type.encode(&mut self.bytes);
+        init.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for TableSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl Section for TableSection {
+    fn id(&self) -> u8 {
+        SectionId::Table.into()
+    }
+}
+
+/// A table's type.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct TableType {
+    /// The table's element type.
+    pub element_type: RefType,
+    /// Whether or not this is a 64-bit table.
+    pub table64: bool,
+    /// Minimum size, in elements, of this table
+    pub minimum: u64,
+    /// Maximum size, in elements, of this table
+    pub maximum: Option<u64>,
+    /// Whether this table is shared or not.
+    ///
+    /// This is included the shared-everything-threads proposal.
+    pub shared: bool,
+}
+
+impl TableType {
+    /// Returns the type used to index this table.
+    pub fn index_type(&self) -> ValType {
+        if self.table64 {
+            ValType::I64
+        } else {
+            ValType::I32
+        }
+    }
+}
+
+impl Encode for TableType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        let mut flags = 0;
+        if self.maximum.is_some() {
+            flags |= 0b001;
+        }
+        if self.shared {
+            flags |= 0b010;
+        }
+        if self.table64 {
+            flags |= 0b100;
+        }
+
+        self.element_type.encode(sink);
+        sink.push(flags);
+        self.minimum.encode(sink);
+
+        if let Some(max) = self.maximum {
+            max.encode(sink);
+        }
+    }
+}

vendor/wasm-encoder/src/core/tags.rs

@@ -0,0 +1,86 @@
+use crate::{Encode, Section, SectionId, encode_section};
+use alloc::vec::Vec;
+
+/// An encoder for the tag section.
+///
+/// # Example
+///
+/// ```
+/// use wasm_encoder::{Module, TagSection, TagType, TagKind};
+///
+/// let mut tags = TagSection::new();
+/// tags.tag(TagType {
+///     kind: TagKind::Exception,
+///     func_type_idx: 0,
+/// });
+///
+/// let mut module = Module::new();
+/// module.section(&tags);
+///
+/// let wasm_bytes = module.finish();
+/// ```
+#[derive(Clone, Default, Debug)]
+pub struct TagSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl TagSection {
+    /// Create a new tag section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of tags in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Define a tag.
+    pub fn tag(&mut self, tag_type: TagType) -> &mut Self {
+        tag_type.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+}
+
+impl Encode for TagSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl Section for TagSection {
+    fn id(&self) -> u8 {
+        SectionId::Tag.into()
+    }
+}
+
+/// Represents a tag kind.
+#[repr(u8)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum TagKind {
+    /// The tag is an exception type.
+    Exception = 0x0,
+}
+
+/// A tag's type.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct TagType {
+    /// The kind of tag
+    pub kind: TagKind,
+    /// The function type this tag uses
+    pub func_type_idx: u32,
+}
+
+impl Encode for TagType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        sink.push(self.kind as u8);
+        self.func_type_idx.encode(sink);
+    }
+}

vendor/wasm-encoder/src/core/types.rs

@@ -0,0 +1,753 @@
+use crate::{Encode, Section, SectionId, encode_section};
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+
+/// Represents a subtype of possible other types in a WebAssembly module.
+#[derive(Debug, Clone)]
+pub struct SubType {
+    /// Is the subtype final.
+    pub is_final: bool,
+    /// The list of supertype indexes. As of GC MVP, there can be at most one
+    /// supertype.
+    pub supertype_idx: Option<u32>,
+    /// The composite type of the subtype.
+    pub composite_type: CompositeType,
+}
+
+/// Represents a composite type in a WebAssembly module.
+#[derive(Debug, Clone)]
+pub struct CompositeType {
+    /// The type defined inside the composite type.
+    pub inner: CompositeInnerType,
+    /// Whether the type is shared. This is part of the
+    /// shared-everything-threads proposal.
+    pub shared: bool,
+    /// Optional descriptor attribute.
+    pub descriptor: Option<u32>,
+    /// Optional describes attribute.
+    pub describes: Option<u32>,
+}
+
+/// A [`CompositeType`] can contain one of these types.
+#[derive(Debug, Clone)]
+pub enum CompositeInnerType {
+    /// The type is for a function.
+    Func(FuncType),
+    /// The type is for an array.
+    Array(ArrayType),
+    /// The type is for a struct.
+    Struct(StructType),
+    /// The type is for a continuation.
+    Cont(ContType),
+}
+
+/// Represents a type of a function in a WebAssembly module.
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+pub struct FuncType {
+    /// The combined parameters and result types.
+    params_results: Box<[ValType]>,
+    /// The number of parameter types.
+    len_params: usize,
+}
+
+/// Represents a type of an array in a WebAssembly module.
+#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
+pub struct ArrayType(pub FieldType);
+
+/// Represents a type of a struct in a WebAssembly module.
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+pub struct StructType {
+    /// Struct fields.
+    pub fields: Box<[FieldType]>,
+}
+
+/// Field type in composite types (structs, arrays).
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
+pub struct FieldType {
+    /// Storage type of the field.
+    pub element_type: StorageType,
+    /// Is the field mutable.
+    pub mutable: bool,
+}
+
+/// Storage type for composite type fields.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
+pub enum StorageType {
+    /// The `i8` type.
+    I8,
+    /// The `i16` type.
+    I16,
+    /// A value type.
+    Val(ValType),
+}
+
+impl StorageType {
+    /// Is this storage type defaultable?
+    pub fn is_defaultable(&self) -> bool {
+        self.unpack().is_defaultable()
+    }
+
+    /// Unpack this storage type into a value type.
+    pub fn unpack(&self) -> ValType {
+        match self {
+            StorageType::I8 | StorageType::I16 => ValType::I32,
+            StorageType::Val(v) => *v,
+        }
+    }
+}
+
+/// Represents a type of a continuation in a WebAssembly module.
+#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
+pub struct ContType(pub u32);
+
+/// The type of a core WebAssembly value.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
+pub enum ValType {
+    /// The `i32` type.
+    I32,
+    /// The `i64` type.
+    I64,
+    /// The `f32` type.
+    F32,
+    /// The `f64` type.
+    F64,
+    /// The `v128` type.
+    ///
+    /// Part of the SIMD proposal.
+    V128,
+    /// A reference type.
+    ///
+    /// The `funcref` and `externref` type fall into this category and the full
+    /// generalization here is due to the implementation of the
+    /// function-references proposal.
+    Ref(RefType),
+}
+
+impl ValType {
+    /// Is this a numeric value type?
+    pub fn is_numeric(&self) -> bool {
+        match self {
+            ValType::I32 | ValType::I64 | ValType::F32 | ValType::F64 => true,
+            ValType::V128 | ValType::Ref(_) => false,
+        }
+    }
+
+    /// Is this a vector type?
+    pub fn is_vector(&self) -> bool {
+        match self {
+            ValType::V128 => true,
+            ValType::I32 | ValType::I64 | ValType::F32 | ValType::F64 | ValType::Ref(_) => false,
+        }
+    }
+
+    /// Is this a reference type?
+    pub fn is_reference(&self) -> bool {
+        match self {
+            ValType::Ref(_) => true,
+            ValType::I32 | ValType::I64 | ValType::F32 | ValType::F64 | ValType::V128 => false,
+        }
+    }
+}
+
+impl FuncType {
+    /// Creates a new [`FuncType`] from the given `params` and `results`.
+    pub fn new<P, R>(params: P, results: R) -> Self
+    where
+        P: IntoIterator<Item = ValType>,
+        R: IntoIterator<Item = ValType>,
+    {
+        let mut buffer = params.into_iter().collect::<Vec<_>>();
+        let len_params = buffer.len();
+        buffer.extend(results);
+        Self::from_parts(buffer.into(), len_params)
+    }
+
+    #[inline]
+    pub(crate) fn from_parts(params_results: Box<[ValType]>, len_params: usize) -> Self {
+        Self {
+            params_results,
+            len_params,
+        }
+    }
+
+    /// Returns a shared slice to the parameter types of the [`FuncType`].
+    #[inline]
+    pub fn params(&self) -> &[ValType] {
+        &self.params_results[..self.len_params]
+    }
+
+    /// Returns a shared slice to the result types of the [`FuncType`].
+    #[inline]
+    pub fn results(&self) -> &[ValType] {
+        &self.params_results[self.len_params..]
+    }
+}
+
+impl ValType {
+    /// Alias for the `funcref` type in WebAssembly
+    pub const FUNCREF: ValType = ValType::Ref(RefType::FUNCREF);
+    /// Alias for the `externref` type in WebAssembly
+    pub const EXTERNREF: ValType = ValType::Ref(RefType::EXTERNREF);
+    /// Alias for the `exnref` type in WebAssembly
+    pub const EXNREF: ValType = ValType::Ref(RefType::EXNREF);
+
+    /// Is this value defaultable?
+    pub fn is_defaultable(&self) -> bool {
+        match self {
+            ValType::Ref(r) => r.nullable,
+            ValType::I32 | ValType::I64 | ValType::F32 | ValType::F64 | ValType::V128 => true,
+        }
+    }
+}
+
+impl Encode for StorageType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            StorageType::I8 => sink.push(0x78),
+            StorageType::I16 => sink.push(0x77),
+            StorageType::Val(vt) => vt.encode(sink),
+        }
+    }
+}
+
+impl Encode for ValType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            ValType::I32 => sink.push(0x7F),
+            ValType::I64 => sink.push(0x7E),
+            ValType::F32 => sink.push(0x7D),
+            ValType::F64 => sink.push(0x7C),
+            ValType::V128 => sink.push(0x7B),
+            ValType::Ref(rt) => rt.encode(sink),
+        }
+    }
+}
+
+/// A reference type.
+///
+/// This is largely part of the function references proposal for WebAssembly but
+/// additionally is used by the `funcref` and `externref` types. The full
+/// generality of this type is only exercised with function-references.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
+#[allow(missing_docs)]
+pub struct RefType {
+    pub nullable: bool,
+    pub heap_type: HeapType,
+}
+
+impl RefType {
+    /// Alias for the `anyref` type in WebAssembly.
+    pub const ANYREF: RefType = RefType {
+        nullable: true,
+        heap_type: HeapType::Abstract {
+            shared: false,
+            ty: AbstractHeapType::Any,
+        },
+    };
+
+    /// Alias for the `anyref` type in WebAssembly.
+    pub const EQREF: RefType = RefType {
+        nullable: true,
+        heap_type: HeapType::Abstract {
+            shared: false,
+            ty: AbstractHeapType::Eq,
+        },
+    };
+
+    /// Alias for the `funcref` type in WebAssembly.
+    pub const FUNCREF: RefType = RefType {
+        nullable: true,
+        heap_type: HeapType::Abstract {
+            shared: false,
+            ty: AbstractHeapType::Func,
+        },
+    };
+
+    /// Alias for the `externref` type in WebAssembly.
+    pub const EXTERNREF: RefType = RefType {
+        nullable: true,
+        heap_type: HeapType::Abstract {
+            shared: false,
+            ty: AbstractHeapType::Extern,
+        },
+    };
+
+    /// Alias for the `i31ref` type in WebAssembly.
+    pub const I31REF: RefType = RefType {
+        nullable: true,
+        heap_type: HeapType::Abstract {
+            shared: false,
+            ty: AbstractHeapType::I31,
+        },
+    };
+
+    /// Alias for the `arrayref` type in WebAssembly.
+    pub const ARRAYREF: RefType = RefType {
+        nullable: true,
+        heap_type: HeapType::Abstract {
+            shared: false,
+            ty: AbstractHeapType::Array,
+        },
+    };
+
+    /// Alias for the `exnref` type in WebAssembly.
+    pub const EXNREF: RefType = RefType {
+        nullable: true,
+        heap_type: HeapType::Abstract {
+            shared: false,
+            ty: AbstractHeapType::Exn,
+        },
+    };
+
+    /// Create a new abstract reference type.
+    pub fn new_abstract(ty: AbstractHeapType, nullable: bool, shared: bool) -> Self {
+        Self {
+            nullable,
+            heap_type: HeapType::Abstract { shared, ty },
+        }
+    }
+
+    /// Set the nullability of this reference type.
+    pub fn nullable(mut self, nullable: bool) -> Self {
+        self.nullable = nullable;
+        self
+    }
+}
+
+impl Encode for RefType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            // Binary abbreviations (i.e., short form), for when the ref is
+            // nullable.
+            RefType {
+                nullable: true,
+                heap_type: heap @ HeapType::Abstract { .. },
+            } => {
+                heap.encode(sink);
+            }
+
+            // Generic 'ref null <heaptype>' encoding (i.e., long form).
+            RefType {
+                nullable: true,
+                heap_type,
+            } => {
+                sink.push(0x63);
+                heap_type.encode(sink);
+            }
+
+            // Generic 'ref <heaptype>' encoding.
+            RefType {
+                nullable: false,
+                heap_type,
+            } => {
+                sink.push(0x64);
+                heap_type.encode(sink);
+            }
+        }
+    }
+}
+
+impl From<RefType> for ValType {
+    fn from(ty: RefType) -> ValType {
+        ValType::Ref(ty)
+    }
+}
+
+/// Part of the function references proposal.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
+pub enum HeapType {
+    /// An abstract heap type; e.g., `anyref`.
+    Abstract {
+        /// Whether the type is shared.
+        shared: bool,
+        /// The actual heap type.
+        ty: AbstractHeapType,
+    },
+
+    /// A concrete Wasm-defined type at the given index.
+    Concrete(u32),
+    /// An exact type.
+    Exact(u32),
+}
+
+impl HeapType {
+    /// Alias for the unshared `any` heap type.
+    pub const ANY: Self = Self::Abstract {
+        shared: false,
+        ty: AbstractHeapType::Any,
+    };
+
+    /// Alias for the unshared `func` heap type.
+    pub const FUNC: Self = Self::Abstract {
+        shared: false,
+        ty: AbstractHeapType::Func,
+    };
+
+    /// Alias for the unshared `extern` heap type.
+    pub const EXTERN: Self = Self::Abstract {
+        shared: false,
+        ty: AbstractHeapType::Extern,
+    };
+
+    /// Alias for the unshared `i31` heap type.
+    pub const I31: Self = Self::Abstract {
+        shared: false,
+        ty: AbstractHeapType::I31,
+    };
+}
+
+impl Encode for HeapType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            HeapType::Abstract { shared, ty } => {
+                if *shared {
+                    sink.push(0x65);
+                }
+                ty.encode(sink);
+            }
+            // Note that this is encoded as a signed type rather than unsigned
+            // as it's decoded as an s33
+            HeapType::Concrete(i) => i64::from(*i).encode(sink),
+            // Exact type is u32
+            HeapType::Exact(i) => {
+                sink.push(0x62);
+                u32::from(*i).encode(sink)
+            }
+        }
+    }
+}
+
+/// An abstract heap type.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
+pub enum AbstractHeapType {
+    /// Untyped (any) function.
+    Func,
+
+    /// The abstract external heap type.
+    Extern,
+
+    /// The abstract `any` heap type.
+    ///
+    /// The common supertype (a.k.a. top) of all internal types.
+    Any,
+
+    /// The abstract `none` heap type.
+    ///
+    /// The common subtype (a.k.a. bottom) of all internal types.
+    None,
+
+    /// The abstract `noextern` heap type.
+    ///
+    /// The common subtype (a.k.a. bottom) of all external types.
+    NoExtern,
+
+    /// The abstract `nofunc` heap type.
+    ///
+    /// The common subtype (a.k.a. bottom) of all function types.
+    NoFunc,
+
+    /// The abstract `eq` heap type.
+    ///
+    /// The common supertype of all referenceable types on which comparison
+    /// (ref.eq) is allowed.
+    Eq,
+
+    /// The abstract `struct` heap type.
+    ///
+    /// The common supertype of all struct types.
+    Struct,
+
+    /// The abstract `array` heap type.
+    ///
+    /// The common supertype of all array types.
+    Array,
+
+    /// The unboxed `i31` heap type.
+    I31,
+
+    /// The abstract `exception` heap type.
+    Exn,
+
+    /// The abstract `noexn` heap type.
+    NoExn,
+
+    /// The abstract `cont` heap type.
+    Cont,
+
+    /// The abstract `nocont` heap type.
+    NoCont,
+}
+
+impl Encode for AbstractHeapType {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        use AbstractHeapType::*;
+        match self {
+            Func => sink.push(0x70),
+            Extern => sink.push(0x6F),
+            Any => sink.push(0x6E),
+            None => sink.push(0x71),
+            NoExtern => sink.push(0x72),
+            NoFunc => sink.push(0x73),
+            Eq => sink.push(0x6D),
+            Struct => sink.push(0x6B),
+            Array => sink.push(0x6A),
+            I31 => sink.push(0x6C),
+            Exn => sink.push(0x69),
+            NoExn => sink.push(0x74),
+            Cont => sink.push(0x68),
+            NoCont => sink.push(0x75),
+        }
+    }
+}
+
+/// An encoder for the type section of WebAssembly modules.
+///
+/// # Example
+///
+/// ```rust
+/// use wasm_encoder::{Module, TypeSection, ValType};
+///
+/// let mut types = TypeSection::new();
+///
+/// types.ty().function([ValType::I32, ValType::I32], [ValType::I64]);
+///
+/// let mut module = Module::new();
+/// module.section(&types);
+///
+/// let bytes = module.finish();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct TypeSection {
+    bytes: Vec<u8>,
+    num_added: u32,
+}
+
+impl TypeSection {
+    /// Create a new module type section encoder.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// The number of types in the section.
+    pub fn len(&self) -> u32 {
+        self.num_added
+    }
+
+    /// Determines if the section is empty.
+    pub fn is_empty(&self) -> bool {
+        self.num_added == 0
+    }
+
+    /// Encode a function type in this type section.
+    #[must_use = "the encoder must be used to encode the type"]
+    pub fn ty(&mut self) -> CoreTypeEncoder<'_> {
+        self.num_added += 1;
+        CoreTypeEncoder {
+            bytes: &mut self.bytes,
+            push_prefix_if_component_core_type: false,
+        }
+    }
+}
+
+impl Encode for TypeSection {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        encode_section(sink, self.num_added, &self.bytes);
+    }
+}
+
+impl Section for TypeSection {
+    fn id(&self) -> u8 {
+        SectionId::Type.into()
+    }
+}
+
+/// A single-use encoder for encoding a type; this forces all encoding for a
+/// type to be done in a single shot.
+#[derive(Debug)]
+pub struct CoreTypeEncoder<'a> {
+    pub(crate) bytes: &'a mut Vec<u8>,
+    // For the time being, this flag handles an ambiguous encoding in the
+    // component model: the `0x50` opcode represents both a core module type as
+    // well as a GC non-final `sub` type. To avoid this, the component model
+    // specification requires us to prefix a non-final `sub` type with `0x00`
+    // when it is used as a top-level core type of a component. Eventually
+    // (prior to the component model's v1.0 release), a module type will get a
+    // new opcode and this special logic can go away.
+    pub(crate) push_prefix_if_component_core_type: bool,
+}
+impl<'a> CoreTypeEncoder<'a> {
+    /// Define a function type in this type section.
+    pub fn function<P, R>(mut self, params: P, results: R)
+    where
+        P: IntoIterator<Item = ValType>,
+        P::IntoIter: ExactSizeIterator,
+        R: IntoIterator<Item = ValType>,
+        R::IntoIter: ExactSizeIterator,
+    {
+        self.encode_function(params, results);
+    }
+
+    /// Define a function type in this type section.
+    pub fn func_type(mut self, ty: &FuncType) {
+        self.encode_function(ty.params().iter().cloned(), ty.results().iter().cloned());
+    }
+
+    fn encode_function<P, R>(&mut self, params: P, results: R)
+    where
+        P: IntoIterator<Item = ValType>,
+        P::IntoIter: ExactSizeIterator,
+        R: IntoIterator<Item = ValType>,
+        R::IntoIter: ExactSizeIterator,
+    {
+        let params = params.into_iter();
+        let results = results.into_iter();
+
+        self.bytes.push(0x60);
+        params.len().encode(self.bytes);
+        params.for_each(|p| p.encode(self.bytes));
+        results.len().encode(self.bytes);
+        results.for_each(|p| p.encode(self.bytes));
+    }
+
+    /// Define an array type in this type section.
+    pub fn array(mut self, ty: &StorageType, mutable: bool) {
+        self.encode_array(ty, mutable);
+    }
+
+    fn encode_array(&mut self, ty: &StorageType, mutable: bool) {
+        self.bytes.push(0x5e);
+        self.encode_field(ty, mutable);
+    }
+
+    fn encode_field(&mut self, ty: &StorageType, mutable: bool) {
+        ty.encode(self.bytes);
+        self.bytes.push(mutable as u8);
+    }
+
+    /// Define a struct type in this type section.
+    pub fn struct_<F>(mut self, fields: F)
+    where
+        F: IntoIterator<Item = FieldType>,
+        F::IntoIter: ExactSizeIterator,
+    {
+        self.encode_struct(fields);
+    }
+
+    fn encode_struct<F>(&mut self, fields: F)
+    where
+        F: IntoIterator<Item = FieldType>,
+        F::IntoIter: ExactSizeIterator,
+    {
+        let fields = fields.into_iter();
+        self.bytes.push(0x5f);
+        fields.len().encode(self.bytes);
+        for f in fields {
+            self.encode_field(&f.element_type, f.mutable);
+        }
+    }
+
+    /// Define a continuation type in this subsection
+    pub fn cont(mut self, ty: &ContType) {
+        self.encode_cont(ty)
+    }
+
+    fn encode_cont(&mut self, ty: &ContType) {
+        self.bytes.push(0x5d);
+        i64::from(ty.0).encode(self.bytes);
+    }
+
+    /// Define an explicit subtype in this type section.
+    pub fn subtype(mut self, ty: &SubType) {
+        self.encode_subtype(ty)
+    }
+
+    /// Define an explicit subtype in this type section.
+    fn encode_subtype(&mut self, ty: &SubType) {
+        // We only need to emit a prefix byte before the actual composite type
+        // when either the `sub` type is not final or it has a declared super
+        // type (see notes on `push_prefix_if_component_core_type`).
+        if ty.supertype_idx.is_some() || !ty.is_final {
+            if ty.is_final {
+                self.bytes.push(0x4f);
+            } else {
+                if self.push_prefix_if_component_core_type {
+                    self.bytes.push(0x00);
+                }
+                self.bytes.push(0x50);
+            }
+            ty.supertype_idx.encode(self.bytes);
+        }
+        if ty.composite_type.shared {
+            self.bytes.push(0x65);
+        }
+        if let Some(index) = ty.composite_type.describes {
+            self.bytes.push(0x4c);
+            index.encode(self.bytes);
+        }
+        if let Some(index) = ty.composite_type.descriptor {
+            self.bytes.push(0x4d);
+            index.encode(self.bytes);
+        }
+        match &ty.composite_type.inner {
+            CompositeInnerType::Func(ty) => {
+                self.encode_function(ty.params().iter().copied(), ty.results().iter().copied())
+            }
+            CompositeInnerType::Array(ArrayType(ty)) => {
+                self.encode_array(&ty.element_type, ty.mutable)
+            }
+            CompositeInnerType::Struct(ty) => self.encode_struct(ty.fields.iter().cloned()),
+            CompositeInnerType::Cont(ty) => self.encode_cont(ty),
+        }
+    }
+
+    /// Define an explicit recursion group in this type section.
+    pub fn rec<T>(mut self, types: T)
+    where
+        T: IntoIterator<Item = SubType>,
+        T::IntoIter: ExactSizeIterator,
+    {
+        // When emitting a `rec` group, we will never emit `sub`'s special
+        // `0x00` prefix; that is only necessary when `sub` is not wrapped by
+        // `rec` (see notes on `push_prefix_if_component_core_type`).
+        self.push_prefix_if_component_core_type = false;
+        let types = types.into_iter();
+        self.bytes.push(0x4e);
+        types.len().encode(self.bytes);
+        types.for_each(|t| {
+            self.encode_subtype(&t);
+        });
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::Module;
+    use wasmparser::WasmFeatures;
+
+    #[test]
+    fn func_types_dont_require_wasm_gc() {
+        let mut types = TypeSection::new();
+        types.ty().subtype(&SubType {
+            is_final: true,
+            supertype_idx: None,
+            composite_type: CompositeType {
+                inner: CompositeInnerType::Func(FuncType::new([], [])),
+                shared: false,
+                descriptor: None,
+                describes: None,
+            },
+        });
+
+        let mut module = Module::new();
+        module.section(&types);
+        let wasm_bytes = module.finish();
+
+        let mut validator =
+            wasmparser::Validator::new_with_features(WasmFeatures::default() & !WasmFeatures::GC);
+
+        validator.validate_all(&wasm_bytes).expect(
+            "Encoding pre Wasm GC type should not accidentally use Wasm GC specific encoding",
+        );
+    }
+}

vendor/wasm-encoder/src/lib.rs

@@ -0,0 +1,224 @@
+//! A WebAssembly encoder.
+//!
+//! The main builder is the [`Module`]. You can build a section with a
+//! section-specific builder, like [`TypeSection`] or [`ImportSection`], and
+//! then add it to the module with [`Module::section`]. When you are finished
+//! building the module, call either [`Module::as_slice`] or [`Module::finish`]
+//! to get the encoded bytes. The former gives a shared reference to the
+//! underlying bytes as a slice, while the latter gives you ownership of them as
+//! a vector.
+//!
+//! # Example
+//!
+//! If we wanted to build this module:
+//!
+//! ```wasm
+//! (module
+//!   (type (func (param i32 i32) (result i32)))
+//!   (func (type 0)
+//!     local.get 0
+//!     local.get 1
+//!     i32.add)
+//!   (export "f" (func 0)))
+//! ```
+//!
+//! then we would do this:
+//!
+//! ```
+//! use wasm_encoder::{
+//!     CodeSection, ExportKind, ExportSection, Function, FunctionSection,
+//!     Module, TypeSection, ValType,
+//! };
+//!
+//! let mut module = Module::new();
+//!
+//! // Encode the type section.
+//! let mut types = TypeSection::new();
+//! let params = vec![ValType::I32, ValType::I32];
+//! let results = vec![ValType::I32];
+//! types.ty().function(params, results);
+//! module.section(&types);
+//!
+//! // Encode the function section.
+//! let mut functions = FunctionSection::new();
+//! let type_index = 0;
+//! functions.function(type_index);
+//! module.section(&functions);
+//!
+//! // Encode the export section.
+//! let mut exports = ExportSection::new();
+//! exports.export("f", ExportKind::Func, 0);
+//! module.section(&exports);
+//!
+//! // Encode the code section.
+//! let mut codes = CodeSection::new();
+//! let locals = vec![];
+//! let mut f = Function::new(locals);
+//! f.instructions()
+//!     .local_get(0)
+//!     .local_get(1)
+//!     .i32_add()
+//!     .end();
+//! codes.function(&f);
+//! module.section(&codes);
+//!
+//! // Extract the encoded Wasm bytes for this module.
+//! let wasm_bytes = module.finish();
+//!
+//! // We generated a valid Wasm module!
+//! assert!(wasmparser::validate(&wasm_bytes).is_ok());
+//! ```
+
+#![cfg_attr(docsrs, feature(doc_cfg))]
+#![no_std]
+#![deny(missing_docs, missing_debug_implementations)]
+
+extern crate alloc;
+#[cfg(feature = "std")]
+#[macro_use]
+extern crate std;
+
+#[cfg(feature = "component-model")]
+mod component;
+mod core;
+mod raw;
+#[cfg(feature = "wasmparser")]
+pub mod reencode;
+
+#[cfg(feature = "component-model")]
+pub use self::component::*;
+pub use self::core::*;
+pub use self::raw::*;
+
+use alloc::vec::Vec;
+
+/// Implemented by types that can be encoded into a byte sink.
+pub trait Encode {
+    /// Encode the type into the given byte sink.
+    fn encode(&self, sink: &mut Vec<u8>);
+}
+
+impl<T: Encode + ?Sized> Encode for &'_ T {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        T::encode(self, sink)
+    }
+}
+
+impl<T: Encode> Encode for [T] {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.len().encode(sink);
+        for item in self {
+            item.encode(sink);
+        }
+    }
+}
+
+impl Encode for [u8] {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.len().encode(sink);
+        sink.extend(self);
+    }
+}
+
+impl Encode for str {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.len().encode(sink);
+        sink.extend_from_slice(self.as_bytes());
+    }
+}
+
+impl Encode for usize {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        assert!(*self <= u32::max_value() as usize);
+        (*self as u32).encode(sink)
+    }
+}
+
+impl Encode for u32 {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        let (value, pos) = leb128fmt::encode_u32(*self).unwrap();
+        sink.extend_from_slice(&value[..pos]);
+    }
+}
+
+impl Encode for i32 {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        let (value, pos) = leb128fmt::encode_s32(*self).unwrap();
+        sink.extend_from_slice(&value[..pos]);
+    }
+}
+
+impl Encode for u64 {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        let (value, pos) = leb128fmt::encode_u64(*self).unwrap();
+        sink.extend_from_slice(&value[..pos]);
+    }
+}
+
+impl Encode for i64 {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        let (value, pos) = leb128fmt::encode_s64(*self).unwrap();
+        sink.extend_from_slice(&value[..pos]);
+    }
+}
+
+fn encode_vec<T, V>(elements: V, sink: &mut Vec<u8>)
+where
+    T: Encode,
+    V: IntoIterator<Item = T>,
+    V::IntoIter: ExactSizeIterator,
+{
+    let elements = elements.into_iter();
+    u32::try_from(elements.len()).unwrap().encode(sink);
+    for x in elements {
+        x.encode(sink);
+    }
+}
+
+impl<T> Encode for Option<T>
+where
+    T: Encode,
+{
+    fn encode(&self, sink: &mut Vec<u8>) {
+        match self {
+            Some(v) => {
+                sink.push(0x01);
+                v.encode(sink);
+            }
+            None => sink.push(0x00),
+        }
+    }
+}
+
+fn encoding_size(n: u32) -> usize {
+    let (_value, pos) = leb128fmt::encode_u32(n).unwrap();
+    pos
+}
+
+fn encode_section(sink: &mut Vec<u8>, count: u32, bytes: &[u8]) {
+    (encoding_size(count) + bytes.len()).encode(sink);
+    count.encode(sink);
+    sink.extend(bytes);
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_encoding_size() {
+        assert_eq!(encoding_size(624485), 3);
+    }
+
+    #[test]
+    fn it_encodes_an_empty_module() {
+        let bytes = Module::new().finish();
+        assert_eq!(bytes, [0x00, b'a', b's', b'm', 0x01, 0x00, 0x00, 0x00]);
+    }
+
+    #[test]
+    fn it_encodes_an_empty_component() {
+        let bytes = Component::new().finish();
+        assert_eq!(bytes, [0x00, b'a', b's', b'm', 0x0d, 0x00, 0x01, 0x00]);
+    }
+}

vendor/wasm-encoder/src/raw.rs

@@ -0,0 +1,32 @@
+use crate::{Encode, Section};
+use alloc::vec::Vec;
+
+/// A section made up of uninterpreted, raw bytes.
+///
+/// Allows you to splat any data into a module or component.
+#[derive(Clone, Copy, Debug)]
+pub struct RawSection<'a> {
+    /// The id for this section.
+    pub id: u8,
+    /// The raw data for this section.
+    pub data: &'a [u8],
+}
+
+impl Encode for RawSection<'_> {
+    fn encode(&self, sink: &mut Vec<u8>) {
+        self.data.encode(sink);
+    }
+}
+
+impl Section for RawSection<'_> {
+    fn id(&self) -> u8 {
+        self.id
+    }
+}
+
+#[cfg(feature = "component-model")]
+impl crate::ComponentSection for RawSection<'_> {
+    fn id(&self) -> u8 {
+        self.id
+    }
+}