Crate walrus 

The walrus WebAssembly transformations library.

GC Proposal Support

Walrus supports the WebAssembly GC proposal, including struct types, array types, subtyping, recursive type groups, and the full set of GC instructions.

Creating GC types

Use ModuleTypes::add_struct, ModuleTypes::add_array, and ModuleTypes::add_composite to create GC types programmatically. For mutually-recursive types, use ModuleTypes::add_rec_group which pre-allocates type IDs for forward references.

GC instructions

All GC instructions (struct.new, array.get, ref.cast, etc.) are available as builder methods on InstrSeqBuilder. See the ir module for the full list of instruction variants.

Re-exports

pub use crate::ir::Local;

pub use crate::ir::LocalId;

pub use crate::ir::InstrLocId;

Modules

dot

Utilities for emitting GraphViz dot files.

ir

Intermediate representation for instructions.

passes

Passes over whole modules or individual functions.

Structs

ArrayType

An array type, consisting of a single field type for all elements.

CodeTransform

Code transformation records, which is used to transform DWARF debug entries.

Data

A data segment.

Element

A passive segment which contains a list of functions

Export

A named item exported from the wasm.

FieldType

A field type for struct and array fields.

Function

A wasm function.

FunctionBuilder

Build instances of LocalFunction.

FunctionType

A function type, consisting of parameter and result types.

Global

A wasm global.

IdsToIndices

Maps our high-level identifiers to the raw indices they end up emitted at.

Import

A named item imported into the wasm.

ImportedFunction

An externally defined, imported function.

IndicesToIds

Maps from old indices in the original Wasm binary to walrus IDs.

InstrSeqBuilder

A builder returned by instruction sequence-construction methods to build up instructions within a block/loop/if-else over time.

LocalFunction

A function defined locally within the wasm module.

Memory

A memory in the wasm.

Module

A wasm module.

ModuleConfig

Configuration for a Module which currently affects parsing.

ModuleCustomSections

A collection of custom sections inside a Wasm module.

ModuleData

All passive data sections of a wasm module, used to initialize memories via various instructions.

ModuleDebugData

The DWARF debug section in input WebAssembly binary.

ModuleElements

All element segments of a wasm module, used to initialize anyfunc tables, used as function pointers.

ModuleExports

The set of exports in a module.

ModuleFunctions

The set of functions within a module.

ModuleGlobals

The set of globals in each function in this module.

ModuleImports

The set of imports in a module.

ModuleLocals

The set of locals in each function in this module.

ModuleMemories

The set of memories in this module.

ModuleProducers

Representation of the wasm custom section producers

ModuleTables

The set of tables in this module.

ModuleTags

All tags in a WebAssembly module.

ModuleTypes

The set of de-duplicated types within a module.

RawCustomSection

A raw, unparsed custom section.

RecGroup

A recursive type group.

RefType

A reference type.

StructType

A struct type, consisting of a sequence of field types.

Table

A table in the wasm.

Tag

A tag in a WebAssembly module, used for exception handling.

Type

A WebAssembly type definition.

TypedCustomSectionId

The id of a CustomSection instance with a statically-known type in a ModuleCustomSections.

UntypedCustomSectionId

The id of some CustomSection instance in a ModuleCustomSections.

Enums

AbstractHeapType

Abstract heap types for GC reference types.

CompositeType

A composite type that can be a function, struct, or array.

ConstExpr

A constant which is produced in WebAssembly, typically used in global initializers or element/data offsets.

ConstOp

Operations allowed in extended constant expressions

DataKind

The kind of data segment: passive or active.

ElementItems

Represents the items of an element segment.

ElementKind

The kind of element segment.

ErrorKind

A leaf wasm error type.

ExportItem

An exported item.

FunctionKind

The local- or external-specific bits of a function.

GlobalKind

The different kinds of globals a wasm module can have

HeapType

A heap type for GC reference types.

ImportKind

An imported item.

StorageType

A packed storage type for struct and array fields.

TagKind

The kind of tag.

ValType

A value type.

Traits

CustomSection

A trait for implementing custom sections.

CustomSectionId

A common trait for custom section identifiers.

Type Aliases

DataId

A passive element segment identifier

ElementId

A passive element segment identifier

ExportId

The id of an export.

FuncParams

Parameter(s) to a function

FuncResults

Result(s) of a given function

FunctionId

A function identifier.

GlobalId

The id of a global.

ImportId

The id of an import.

MemoryId

The id of a memory.

RecGroupId

An identifier for recursive type groups.

Result

Either Ok(T) or Err(failure::Error). Result<T, Error>

TableId

The id of a table.

TagId

The id of a tag.

TypeId

An identifier for types.