Module wasmtime_environ::component

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Expand description

Support for the component model in Wasmtime.

This module contains all of the internal type definitions used by Wasmtime to process the component model. Despite everything being pub here this is not the public interface of Wasmtime to the component model. Instead this is the internal support to mirror the core wasm support that Wasmtime already implements.

Some main items contained within here are:

  • Type hierarchy information for the component model
  • Translation of a component into Wasmtime’s representation
  • Type information about a component used at runtime

This module also contains a lot of Serialize/Deserialize types which are encoded in the final compiled image for a component.

Note that this entire module is gated behind the component-model Cargo feature.

§Warning: In-progress

As-of the time of this writing this module is incomplete and under development. It will be added to incrementally over time as more features are implemented. Current design decisions are also susceptible to change at any time. Some comments may reflect historical rather than current state as well (sorry).

Modules§

  • dfg
    A dataflow-graph-like intermediate representation of a component

Structs§

  • Adapter
    Metadata information about a fused adapter.
  • AdapterOptions
    Configuration options which can be specified as part of the canonical ABI in the component model.
  • AllCallFunc
    A triple of related functions/trampolines variants with differing calling conventions: {wasm,array}_call.
  • CanonicalAbiInfo
    Bye information about a type in the canonical ABI, with metadata for both memory32 and memory64-based types.
  • CanonicalOptions
    Canonical ABI options associated with a lifted or lowered function.
  • CompiledComponentInfo
    Runtime state that a component retains to support its operation.
  • Component
    Run-time-type-information about a Component, its structure, and how to instantiate it.
  • ComponentArtifacts
    Serializable state that’s stored in a compilation artifact.
  • ComponentFuncIndex
    Index within a component’s component function index space.
  • ComponentIndex
    Index within a component’s component index space.
  • ComponentInstanceIndex
    Index within a component’s component instance index space.
  • ComponentTranslation
    Metadata as a result of compiling a component.
  • ComponentTypeIndex
    Index within a component’s component type index space.
  • ComponentTypes
    Runtime information about the type information contained within a component.
  • ComponentTypesBuilder
    Structured used to build a ComponentTypes during translation.
  • ComponentUpvarIndex
    Same as ModuleUpvarIndex but for components.
  • CoreExport
    Identifier of an exported item from a core WebAssembly module instance.
  • DefinedResourceIndex
    Index pointing to a local resource defined within a component.
  • ExportIndex
    An index into Component::export_items at the end of compilation.
  • ExtractMemory
    Metadata for extraction of a memory of what’s being extracted and where it’s going.
  • ExtractPostReturn
    Same as ExtractMemory but for the post-return canonical option.
  • ExtractRealloc
    Same as ExtractMemory but for the realloc canonical option.
  • FlatTypes
    Flat representation of a type in just core wasm types.
  • FuncIndex
    Index type of a function (imported or defined) inside the WebAssembly module.
  • GlobalIndex
    Index type of a global variable (imported or defined) inside the WebAssembly module.
  • ImportIndex
    Used to index imports into a Component
  • LoweredIndex
    Index that represents a lowered host function and is used to represent host function lowerings with options and such.
  • MemoryIndex
    Index type of a linear memory (imported or defined) inside the WebAssembly module.
  • ModuleIndex
    Index within a component’s module index space.
  • ModuleInstanceIndex
    Index within a component’s module instance index space.
  • ModuleUpvarIndex
    Index into a “closed over variables” list for components used to implement outer aliases. For more information on this see the documentation for the LexicalScope structure.
  • NameMap
    A semver-aware map for imports/exports of a component.
  • NameMapNoIntern
    For use with NameMap when no interning should happen and instead string keys are copied as-is.
  • RecordField
    One field within a record.
  • Resource
    Description of a new resource declared in a GlobalInitializer::Resource variant.
  • ResourceIndex
    Index pointing to a resource within a component.
  • ResourcesBuilder
    Builder state used to translate wasmparser’s ResourceId types to Wasmtime’s TypeResourceTableIndex type.
  • RuntimeComponentInstanceIndex
    Same as RuntimeInstanceIndex but tracks component instances instead.
  • RuntimeImportIndex
    Index that represents a leaf item imported into a component where a “leaf” means “not an instance”.
  • RuntimeInstanceIndex
    Index that represents a core wasm instance created at runtime.
  • RuntimeMemoryIndex
    Index representing a linear memory extracted from a wasm instance which is stored in a VMComponentContext. This is used to deduplicate references to the same linear memory where it’s only stored once in a VMComponentContext.
  • RuntimePostReturnIndex
    Same as RuntimeMemoryIndex except for the post-return function.
  • RuntimeReallocIndex
    Same as RuntimeMemoryIndex except for the realloc function.
  • StaticComponentIndex
    Same as StaticModuleIndex but for components.
  • StaticModuleIndex
    Index into the global list of modules found within an entire component.
  • TableIndex
    Index type of a table (imported or defined) inside the WebAssembly module.
  • TrampolineIndex
    Index for all trampolines that are compiled in Cranelift for a component.
  • Translator
    Structure used to translate a component and parse it.
  • TypeComponent
    The type of a component in the component model.
  • TypeComponentIndex
    Index pointing to a component’s type (exports/imports with component-model types)
  • TypeComponentInstance
    The type of a component instance in the component model, or an instantiated component.
  • TypeComponentInstanceIndex
    Index pointing to a component instance’s type (exports with component-model types, no imports)
  • TypeEnum
    Shape of an “enum” type in interface types, not to be confused with a Rust enum type.
  • TypeEnumIndex
    Index pointing to an enum type in the component model.
  • TypeFlags
    Shape of a “flags” type in interface types.
  • TypeFlagsIndex
    Index pointing to a flags type in the component model.
  • TypeFunc
    A component function type in the component model.
  • TypeFuncIndex
    Index pointing to a component model function type with arguments/result as interface types.
  • TypeList
    Shape of a “list” interface type.
  • TypeListIndex
    Index pointing to a list type in the component model.
  • TypeModule
    The type of a module in the component model.
  • TypeModuleIndex
    Index pointing to a core wasm module’s type (exports/imports with core wasm types)
  • TypeOption
    Shape of an “option” interface type.
  • TypeOptionIndex
    Index pointing to an option type in the component model (aka a Option<T, E>)
  • TypeRecord
    Shape of a “record” type in interface types.
  • TypeRecordIndex
    Index pointing to a record type in the component model (aka a struct).
  • TypeResourceTable
    Metadata about a resource table added to a component.
  • TypeResourceTableIndex
    Index pointing to a resource table within a component.
  • TypeResult
    Shape of a “result” interface type.
  • TypeResultIndex
    Index pointing to an result type in the component model (aka a Result<T, E>)
  • TypeTuple
    Shape of a “tuple” type in interface types.
  • TypeTupleIndex
    Index pointing to a tuple type in the component model.
  • TypeVariant
    Shape of a “variant” type in interface types.
  • TypeVariantIndex
    Index pointing to a variant type in the component model (aka an enum).
  • VMComponentOffsets
    Runtime offsets within a VMComponentContext for a specific component.
  • VariantInfo
    ABI information about the representation of a variant.

Enums§

  • ComponentItem
    Equivalent of EntityIndex but for the component model instead of core wasm.
  • CoreDef
    Definition of a core wasm item and where it can come from within a component.
  • Export
    Possible exports from a component.
  • ExportItem
    An index at which to find an item within a runtime instance.
  • FixedEncoding
  • FlatType
  • GlobalInitializer
    GlobalInitializer instructions to get processed when instantiating a component
  • InstantiateModule
    Different methods of instantiating a core wasm module.
  • InterfaceType
    All possible interface types that values can have.
  • StringEncoding
    Possible encodings of strings within the component model.
  • Trampoline
    A list of all possible trampolines that may be required to compile a component completely.
  • Transcode
    Possible transcoding operations that must be provided by the host.
  • TypeDef
    Types of imports and exports in the component model.

Constants§

  • FLAG_MAY_ENTER
    Flag for the VMComponentContext::flags field which corresponds to the canonical ABI flag may_enter
  • FLAG_MAY_LEAVE
    Flag for the VMComponentContext::flags field which corresponds to the canonical ABI flag may_leave
  • FLAG_NEEDS_POST_RETURN
    Flag for the VMComponentContext::flags field which is set whenever a function is called to indicate that post_return must be called next.
  • MAX_FLAT_PARAMS
    Canonical ABI-defined constant for the maximum number of “flat” parameters to a wasm function, or the maximum number of parameters a core wasm function will take for just the parameters used. Over this number the heap is used for transferring parameters.
  • MAX_FLAT_RESULTS
    Canonical ABI-defined constant for the maximum number of “flat” results. This number of results are returned directly from wasm and otherwise results are transferred through memory.
  • MAX_FLAT_TYPES
    Maximum number of flat types, for either params or results.
  • VMCOMPONENT_MAGIC
    Equivalent of VMCONTEXT_MAGIC except for components.

Traits§