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/* Copyright 2018 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
use crate::limits::{
MAX_WASM_FUNCTION_PARAMS, MAX_WASM_FUNCTION_RETURNS, MAX_WASM_STRUCT_FIELDS,
MAX_WASM_SUPERTYPES, MAX_WASM_TYPES,
};
use crate::types::CoreTypeId;
use crate::{BinaryReader, BinaryReaderError, FromReader, Result, SectionLimited};
use std::fmt::{self, Debug, Write};
use std::hash::{Hash, Hasher};
mod matches;
pub(crate) use self::matches::{Matches, WithRecGroup};
/// A packed representation of a type index.
///
/// This type is morally an `enum` of either:
///
/// 1. An index into a Wasm module's type space.
///
/// 2. A `CoreTypeId` identifier.
///
/// 3. An index into a recursion group's elements.
///
/// The latter two variants are *canonical* while the first is not. Reading raw
/// types will produce (1), while working with types after validation will
/// produce (2) and (3).
//
// This is a bit-packed `u32` with the following layout:
//
// [ unused:u10 kind:u2 index:u20 ]
//
// It must fit in 22 bits to keep `RefType` in 24 bits and `ValType` in 32 bits,
// so the top ten bits are unused.
//
// The `index` field's interpretation depends on the `kind` field, which may be
// one of the following:
//
// * `00`: The `index` is an index into the module's type space.
//
// * `01`: The `index` is an index into the containing type's recursion group.
//
// * `10`: The `index` is a `CoreTypeId`.
#[derive(Copy, Clone, PartialEq, Eq, Hash)]
pub struct PackedIndex(u32);
// Assert that we can fit indices up to `MAX_WASM_TYPES` inside `RefType`.
#[test]
fn can_fit_max_wasm_types_in_packed_index() {
assert!(PackedIndex::can_represent_index(
crate::limits::MAX_WASM_TYPES as u32
));
assert!(PackedIndex::can_represent_index(
0b00000000_00001111_00000000_00000000
));
assert!(PackedIndex::can_represent_index(
0b00000000_00000000_11111111_00000000
));
assert!(PackedIndex::can_represent_index(
0b00000000_00000000_00000000_11111111
));
assert!(PackedIndex::can_represent_index(0));
}
impl PackedIndex {
const UNUSED_MASK: u32 = u32::MAX & !(Self::KIND_MASK | Self::INDEX_MASK);
const KIND_MASK: u32 = 0b11 << 20;
const INDEX_MASK: u32 = (1 << 20) - 1;
const MODULE_KIND: u32 = 0b00 << 20;
const REC_GROUP_KIND: u32 = 0b01 << 20;
const ID_KIND: u32 = 0b10 << 20;
#[inline]
pub(crate) fn unchecked_from_u32(x: u32) -> Self {
debug_assert_eq!(Self::UNUSED_MASK & x, 0);
Self(x)
}
#[inline]
pub(crate) fn to_u32(id: Self) -> u32 {
let x = id.0;
debug_assert_eq!(Self::UNUSED_MASK & x, 0);
x
}
#[inline]
fn can_represent_index(index: u32) -> bool {
index & Self::INDEX_MASK == index
}
#[inline]
fn kind(&self) -> u32 {
self.0 & Self::KIND_MASK
}
#[inline]
fn index(&self) -> u32 {
self.0 & Self::INDEX_MASK
}
/// Construct a `PackedIndex` from an index into a module's types space.
#[inline]
pub fn from_module_index(index: u32) -> Option<Self> {
if PackedIndex::can_represent_index(index) {
Some(PackedIndex(PackedIndex::MODULE_KIND | index))
} else {
None
}
}
/// Construct a `PackedIndex` from an index into the index's containing
/// recursion group.
#[inline]
pub fn from_rec_group_index(index: u32) -> Option<Self> {
if PackedIndex::can_represent_index(index) {
Some(PackedIndex(PackedIndex::REC_GROUP_KIND | index))
} else {
None
}
}
/// Construct a `PackedIndex` from the given `CoreTypeId`.
#[inline]
pub fn from_id(id: CoreTypeId) -> Option<Self> {
let index = u32::try_from(crate::types::TypeIdentifier::index(&id)).unwrap();
if PackedIndex::can_represent_index(index) {
Some(PackedIndex(PackedIndex::ID_KIND | index))
} else {
None
}
}
/// Is this index in canonical form?
#[inline]
pub fn is_canonical(&self) -> bool {
match self.kind() {
Self::REC_GROUP_KIND | Self::ID_KIND => true,
Self::MODULE_KIND => false,
_ => unreachable!(),
}
}
/// Uncompress this packed index into an actual `enum` that can be matched
/// on.
#[inline]
pub fn unpack(&self) -> UnpackedIndex {
match self.kind() {
Self::MODULE_KIND => UnpackedIndex::Module(self.index()),
Self::REC_GROUP_KIND => UnpackedIndex::RecGroup(self.index()),
Self::ID_KIND => UnpackedIndex::Id(
<CoreTypeId as crate::types::TypeIdentifier>::from_index(self.index()),
),
_ => unreachable!(),
}
}
/// Get the underlying index into a module's types space, if any.
#[inline]
pub fn as_module_index(&self) -> Option<u32> {
if self.kind() == Self::MODULE_KIND {
Some(self.index())
} else {
None
}
}
/// Get the underlying index into the containing recursion group, if any.
#[inline]
pub fn as_rec_group_index(&self) -> Option<u32> {
if self.kind() == Self::REC_GROUP_KIND {
Some(self.index())
} else {
None
}
}
/// Get the underlying `CoreTypeId`, if any.
#[inline]
pub fn as_core_type_id(&self) -> Option<CoreTypeId> {
if self.kind() == Self::ID_KIND {
Some(<CoreTypeId as crate::types::TypeIdentifier>::from_index(
self.index(),
))
} else {
None
}
}
}
impl std::fmt::Debug for PackedIndex {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("CoreTypeIndex")
.field(
"kind",
match self.kind() {
Self::MODULE_KIND => &"module",
Self::REC_GROUP_KIND => &"recgroup",
Self::ID_KIND => &"id",
_ => unreachable!(),
},
)
.field("index", &self.index())
.finish()
}
}
impl std::fmt::Display for PackedIndex {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
std::fmt::Display::fmt(&self.unpack(), f)
}
}
/// The uncompressed form of a `PackedIndex`.
///
/// Can be used for `match` statements.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub enum UnpackedIndex {
/// An index into a Wasm module's types space.
Module(u32),
/// An index into the containing recursion group's elements.
RecGroup(u32),
/// A type identifier.
Id(CoreTypeId),
}
impl UnpackedIndex {
/// Compress this index into its packed form.
///
/// Returns `None` if an index is beyond implementation limits.
pub fn pack(&self) -> Option<PackedIndex> {
match self {
UnpackedIndex::Module(i) => PackedIndex::from_module_index(*i),
UnpackedIndex::RecGroup(i) => PackedIndex::from_rec_group_index(*i),
UnpackedIndex::Id(id) => PackedIndex::from_id(*id),
}
}
/// Is this index in canonical form?
#[inline]
pub fn is_canonical(&self) -> bool {
matches!(self, UnpackedIndex::RecGroup(_) | UnpackedIndex::Id(_))
}
/// Get the underlying index into a module's types space, if any.
#[inline]
pub fn as_module_index(&self) -> Option<u32> {
if let Self::Module(i) = *self {
Some(i)
} else {
None
}
}
/// Get the underlying index into the containing recursion group, if any.
#[inline]
pub fn as_rec_group_index(&self) -> Option<u32> {
if let Self::RecGroup(i) = *self {
Some(i)
} else {
None
}
}
/// Get the underlying `CoreTypeId`, if any.
#[inline]
pub fn as_core_type_id(&self) -> Option<CoreTypeId> {
if let Self::Id(id) = *self {
Some(id)
} else {
None
}
}
}
impl std::fmt::Display for UnpackedIndex {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
UnpackedIndex::Module(i) => write!(f, "(module {i})"),
UnpackedIndex::RecGroup(i) => write!(f, "(recgroup {i})"),
UnpackedIndex::Id(id) => write!(f, "(id {})", crate::types::TypeIdentifier::index(id)),
}
}
}
/// Represents a recursive type group in a WebAssembly module.
#[derive(Debug, Clone)]
pub struct RecGroup {
inner: RecGroupInner,
}
#[derive(Debug, Clone)]
enum RecGroupInner {
Implicit((usize, SubType)),
Explicit(Vec<(usize, SubType)>),
}
impl RecGroup {
/// Create an explicit `RecGroup` for the given types.
pub(crate) fn explicit(types: Vec<(usize, SubType)>) -> Self {
RecGroup {
inner: RecGroupInner::Explicit(types),
}
}
/// Create an implicit `RecGroup` for a type that was not contained
/// in a `(rec ...)`.
pub(crate) fn implicit(offset: usize, ty: SubType) -> Self {
RecGroup {
inner: RecGroupInner::Implicit((offset, ty)),
}
}
/// Is this an explicit recursion group?
pub fn is_explicit_rec_group(&self) -> bool {
matches!(self.inner, RecGroupInner::Explicit(..))
}
/// Returns the list of subtypes in the recursive type group.
pub fn types(&self) -> impl ExactSizeIterator<Item = &SubType> + '_ {
let types = match &self.inner {
RecGroupInner::Implicit(ty) => std::slice::from_ref(ty),
RecGroupInner::Explicit(types) => types,
};
types.iter().map(|(_, ty)| ty)
}
/// Return a mutable borrow of the list of subtypes in this
/// recursive type group.
pub(crate) fn types_mut(&mut self) -> impl ExactSizeIterator<Item = &mut SubType> + '_ {
let types = match &mut self.inner {
RecGroupInner::Implicit(ty) => std::slice::from_mut(ty),
RecGroupInner::Explicit(types) => types,
};
types.iter_mut().map(|(_, ty)| ty)
}
/// Returns an owning iterator of all subtypes in this recursion
/// group.
pub fn into_types(self) -> impl ExactSizeIterator<Item = SubType> {
self.into_types_and_offsets().map(|(_, ty)| ty)
}
/// Returns an owning iterator of all subtypes in this recursion
/// group, along with their offset.
pub fn into_types_and_offsets(self) -> impl ExactSizeIterator<Item = (usize, SubType)> {
return match self.inner {
RecGroupInner::Implicit(tup) => Iter::Implicit(Some(tup)),
RecGroupInner::Explicit(types) => Iter::Explicit(types.into_iter()),
};
enum Iter {
Implicit(Option<(usize, SubType)>),
Explicit(std::vec::IntoIter<(usize, SubType)>),
}
impl Iterator for Iter {
type Item = (usize, SubType);
fn next(&mut self) -> Option<(usize, SubType)> {
match self {
Self::Implicit(ty) => ty.take(),
Self::Explicit(types) => types.next(),
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
match self {
Self::Implicit(None) => (0, Some(0)),
Self::Implicit(Some(_)) => (1, Some(1)),
Self::Explicit(types) => types.size_hint(),
}
}
}
impl ExactSizeIterator for Iter {}
}
}
impl Hash for RecGroup {
fn hash<H: Hasher>(&self, hasher: &mut H) {
let types = self.types();
types.len().hash(hasher);
for ty in types {
ty.hash(hasher);
}
}
}
impl PartialEq for RecGroup {
fn eq(&self, other: &RecGroup) -> bool {
let self_tys = self.types();
let other_tys = other.types();
self_tys.len() == other_tys.len() && self_tys.zip(other_tys).all(|(a, b)| a == b)
}
}
impl Eq for RecGroup {}
/// Represents a subtype of possible other types in a WebAssembly module.
#[derive(Debug, Clone, Hash, PartialEq, Eq)]
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<PackedIndex>,
/// The composite type of the subtype.
pub composite_type: CompositeType,
}
impl std::fmt::Display for SubType {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
if self.is_final && self.supertype_idx.is_none() {
std::fmt::Display::fmt(&self.composite_type, f)
} else {
write!(f, "(sub ")?;
if self.is_final {
write!(f, "final ")?;
}
if let Some(idx) = self.supertype_idx {
write!(f, "{idx} ")?;
}
std::fmt::Display::fmt(&self.composite_type, f)?;
write!(f, ")")
}
}
}
impl SubType {
/// Unwrap an `ArrayType` or panic.
///
/// Does not check finality or whether there is a supertype.
pub fn unwrap_array(&self) -> &ArrayType {
self.composite_type.unwrap_array()
}
/// Unwrap an `FuncType` or panic.
///
/// Does not check finality or whether there is a supertype.
pub fn unwrap_func(&self) -> &FuncType {
self.composite_type.unwrap_func()
}
/// Unwrap an `StructType` or panic.
///
/// Does not check finality or whether there is a supertype.
pub fn unwrap_struct(&self) -> &StructType {
self.composite_type.unwrap_struct()
}
/// Maps any `UnpackedIndex` via the specified closure.
pub(crate) fn remap_indices(
&mut self,
f: &mut dyn FnMut(&mut PackedIndex) -> Result<()>,
) -> Result<()> {
if let Some(idx) = &mut self.supertype_idx {
f(idx)?;
}
match &mut self.composite_type {
CompositeType::Func(ty) => {
for ty in ty.params_mut() {
ty.remap_indices(f)?;
}
for ty in ty.results_mut() {
ty.remap_indices(f)?;
}
}
CompositeType::Array(ty) => {
ty.0.remap_indices(f)?;
}
CompositeType::Struct(ty) => {
for field in ty.fields.iter_mut() {
field.remap_indices(f)?;
}
}
}
Ok(())
}
}
/// Represents a composite type in a WebAssembly module.
#[derive(Debug, Clone, Hash, PartialEq, Eq)]
pub enum CompositeType {
/// The type is for a function.
Func(FuncType),
/// The type is for an array.
Array(ArrayType),
/// The type is for a struct.
Struct(StructType),
}
impl std::fmt::Display for CompositeType {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
Self::Array(_) => write!(f, "(array ...)"),
Self::Func(_) => write!(f, "(func ...)"),
Self::Struct(_) => write!(f, "(struct ...)"),
}
}
}
impl CompositeType {
/// Unwrap a `FuncType` or panic.
pub fn unwrap_func(&self) -> &FuncType {
match self {
Self::Func(f) => f,
_ => panic!("not a func"),
}
}
/// Unwrap a `ArrayType` or panic.
pub fn unwrap_array(&self) -> &ArrayType {
match self {
Self::Array(a) => a,
_ => panic!("not a array"),
}
}
/// Unwrap a `StructType` or panic.
pub fn unwrap_struct(&self) -> &StructType {
match self {
Self::Struct(s) => s,
_ => panic!("not a struct"),
}
}
}
/// Represents a type of a function in a WebAssembly module.
#[derive(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,
}
impl std::fmt::Debug for FuncType {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("FuncType")
.field("params", &self.params())
.field("results", &self.results())
.finish()
}
}
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 {
params_results: buffer.into(),
len_params,
}
}
/// Creates a new [`FuncType`] fom its raw parts.
///
/// # Panics
///
/// If `len_params` is greater than the length of `params_results` combined.
pub(crate) fn from_raw_parts(params_results: Box<[ValType]>, len_params: usize) -> Self {
assert!(len_params <= params_results.len());
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 an exclusive slice to the parameter types of the
/// [`FuncType`].
#[inline]
pub(crate) fn params_mut(&mut self) -> &mut [ValType] {
&mut 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..]
}
/// Returns an exclusive slice to the result types of the
/// [`FuncType`].
#[inline]
pub(crate) fn results_mut(&mut self) -> &mut [ValType] {
&mut self.params_results[self.len_params..]
}
pub(crate) fn desc(&self) -> String {
let mut s = String::new();
s.push_str("[");
for (i, param) in self.params().iter().enumerate() {
if i > 0 {
s.push_str(" ");
}
write!(s, "{param}").unwrap();
}
s.push_str("] -> [");
for (i, result) in self.results().iter().enumerate() {
if i > 0 {
s.push_str(" ");
}
write!(s, "{result}").unwrap();
}
s.push_str("]");
s
}
}
/// Represents a type of an array in a WebAssembly module.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub struct ArrayType(pub FieldType);
/// Represents a field type of an array or a struct.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub struct FieldType {
/// Array element type.
pub element_type: StorageType,
/// Are elements mutable.
pub mutable: bool,
}
impl FieldType {
/// Maps any `UnpackedIndex` via the specified closure.
pub(crate) fn remap_indices(
&mut self,
f: &mut dyn FnMut(&mut PackedIndex) -> Result<()>,
) -> Result<()> {
match &mut self.element_type {
StorageType::I8 | StorageType::I16 => Ok(()),
StorageType::Val(ty) => ty.remap_indices(f),
}
}
}
/// Represents storage types introduced in the GC spec for array and struct fields.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub enum StorageType {
/// The storage type is i8.
I8,
/// The storage type is i16.
I16,
/// The storage type is a value type.
Val(ValType),
}
impl std::fmt::Display for StorageType {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::I8 => write!(f, "i8"),
Self::I16 => write!(f, "i16"),
Self::Val(v) => std::fmt::Display::fmt(v, f),
}
}
}
impl StorageType {
/// Is this a packed storage type, i.e. one that must be sign- or
/// zero-extended when converted to a `ValType`?
pub fn is_packed(&self) -> bool {
match self {
Self::I8 | Self::I16 => true,
Self::Val(_) => false,
}
}
/// Unpack this storage type into the valtype that it is represented as on
/// the operand stack.
pub fn unpack(&self) -> ValType {
match *self {
Self::Val(ty) => ty,
Self::I8 | Self::I16 => ValType::I32,
}
}
}
/// 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]>,
}
/// Represents the types of values in a WebAssembly module.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub enum ValType {
/// The value type is i32.
I32,
/// The value type is i64.
I64,
/// The value type is f32.
F32,
/// The value type is f64.
F64,
/// The value type is v128.
V128,
/// The value type is a reference.
Ref(RefType),
}
impl From<RefType> for ValType {
#[inline]
fn from(ty: RefType) -> ValType {
ValType::Ref(ty)
}
}
impl std::fmt::Display for ValType {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
ValType::I32 => f.write_str("i32"),
ValType::I64 => f.write_str("i64"),
ValType::F32 => f.write_str("f32"),
ValType::F64 => f.write_str("f64"),
ValType::V128 => f.write_str("v128"),
ValType::Ref(r) => std::fmt::Display::fmt(r, f),
}
}
}
impl ValType {
/// Alias for the wasm `funcref` type.
pub const FUNCREF: ValType = ValType::Ref(RefType::FUNCREF);
/// Alias for the wasm `externref` type.
pub const EXTERNREF: ValType = ValType::Ref(RefType::EXTERNREF);
/// Alias for the wasm `exnref` type.
pub const EXNREF: ValType = ValType::Ref(RefType::EXNREF);
/// Returns whether this value type is a "reference type".
///
/// Only reference types are allowed in tables, for example, and with some
/// instructions. Current reference types include `funcref` and `externref`.
pub fn is_reference_type(&self) -> bool {
matches!(self, ValType::Ref(_))
}
/// Get the underlying reference type, if any.
pub fn as_reference_type(&self) -> Option<RefType> {
match *self {
ValType::Ref(r) => Some(r),
ValType::I32 | ValType::I64 | ValType::F32 | ValType::F64 | ValType::V128 => None,
}
}
/// Whether the type is defaultable, i.e. it is not a non-nullable reference
/// type.
pub fn is_defaultable(&self) -> bool {
match *self {
Self::I32 | Self::I64 | Self::F32 | Self::F64 | Self::V128 => true,
Self::Ref(rt) => rt.is_nullable(),
}
}
/// Maps any `UnpackedIndex` via the specified closure.
pub(crate) fn remap_indices(
&mut self,
map: &mut dyn FnMut(&mut PackedIndex) -> Result<()>,
) -> Result<()> {
match self {
ValType::Ref(r) => {
if let Some(mut idx) = r.type_index() {
map(&mut idx)?;
*r = RefType::concrete(r.is_nullable(), idx);
}
}
ValType::I32 | ValType::I64 | ValType::F32 | ValType::F64 | ValType::V128 => {}
}
Ok(())
}
}
/// A reference type.
///
/// The reference types proposal first introduced `externref` and
/// `funcref`.
///
/// The function references proposal introduced typed function
/// references.
///
/// The GC proposal introduces heap types: any, eq, i31, struct, array,
/// nofunc, noextern, none.
//
// RefType is a bit-packed enum that fits in a `u24` aka `[u8; 3]`.
// Note that its content is opaque (and subject to change), but its API
// is stable.
//
// It has the following internal structure:
//
// ```
// [nullable:u1 concrete==1:u1 index:u22]
// [nullable:u1 concrete==0:u1 abstype:u4 (unused):u18]
// ```
//
// Where
//
// - `nullable` determines nullability of the ref,
//
// - `concrete` determines if the ref is of a dynamically defined type
// with an index (encoded in a following bit-packing section) or of a
// known fixed type,
//
// - `index` is the type index,
//
// - `abstype` is an enumeration of abstract types:
//
// ```
// 1111 = any
//
// 1101 = eq
// 1000 = i31
// 1001 = struct
// 1100 = array
//
// 0101 = func
// 0100 = nofunc
//
// 0011 = extern
// 0010 = noextern
//
// 0001 = exn
//
// 0000 = none
// ```
#[derive(Copy, Clone, PartialEq, Eq, Hash)]
pub struct RefType([u8; 3]);
impl std::fmt::Debug for RefType {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match (self.is_nullable(), self.heap_type()) {
(true, HeapType::Any) => write!(f, "anyref"),
(false, HeapType::Any) => write!(f, "(ref any)"),
(true, HeapType::None) => write!(f, "nullref"),
(false, HeapType::None) => write!(f, "(ref none)"),
(true, HeapType::NoExtern) => write!(f, "nullexternref"),
(false, HeapType::NoExtern) => write!(f, "(ref noextern)"),
(true, HeapType::NoFunc) => write!(f, "nullfuncref"),
(false, HeapType::NoFunc) => write!(f, "(ref nofunc)"),
(true, HeapType::Eq) => write!(f, "eqref"),
(false, HeapType::Eq) => write!(f, "(ref eq)"),
(true, HeapType::Struct) => write!(f, "structref"),
(false, HeapType::Struct) => write!(f, "(ref struct)"),
(true, HeapType::Array) => write!(f, "arrayref"),
(false, HeapType::Array) => write!(f, "(ref array)"),
(true, HeapType::I31) => write!(f, "i31ref"),
(false, HeapType::I31) => write!(f, "(ref i31)"),
(true, HeapType::Extern) => write!(f, "externref"),
(false, HeapType::Extern) => write!(f, "(ref extern)"),
(true, HeapType::Func) => write!(f, "funcref"),
(false, HeapType::Func) => write!(f, "(ref func)"),
(true, HeapType::Exn) => write!(f, "exnref"),
(false, HeapType::Exn) => write!(f, "(ref exn)"),
(true, HeapType::Concrete(idx)) => write!(f, "(ref null {idx})"),
(false, HeapType::Concrete(idx)) => write!(f, "(ref {idx})"),
}
}
}
impl std::fmt::Display for RefType {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
std::fmt::Debug::fmt(self, f)
}
}
// Assert that we can fit indices up to `MAX_WASM_TYPES` inside `RefType`.
#[test]
fn can_fit_max_wasm_types_in_ref_type() {
fn can_roundtrip_index(index: u32) -> bool {
assert!(RefType::can_represent_type_index(index));
let rt = RefType::concrete(true, PackedIndex::from_module_index(index).unwrap());
assert!(rt.is_nullable());
let actual_index = match rt.type_index() {
Some(i) => i,
None => panic!(),
};
actual_index.as_module_index() == Some(index)
}
assert!(can_roundtrip_index(crate::limits::MAX_WASM_TYPES as u32));
assert!(can_roundtrip_index(0b00000000_00001111_00000000_00000000));
assert!(can_roundtrip_index(0b00000000_00000000_11111111_00000000));
assert!(can_roundtrip_index(0b00000000_00000000_00000000_11111111));
assert!(can_roundtrip_index(0));
}
impl RefType {
// These bits are valid for all `RefType`s.
const NULLABLE_BIT: u32 = 1 << 23;
const CONCRETE_BIT: u32 = 1 << 22;
// The `abstype` field is valid only when `concrete == 0`.
const ABSTYPE_MASK: u32 = 0b1111 << 18;
const ANY_ABSTYPE: u32 = 0b1111 << 18;
const EQ_ABSTYPE: u32 = 0b1101 << 18;
const I31_ABSTYPE: u32 = 0b1000 << 18;
const STRUCT_ABSTYPE: u32 = 0b1001 << 18;
const ARRAY_ABSTYPE: u32 = 0b1100 << 18;
const FUNC_ABSTYPE: u32 = 0b0101 << 18;
const NOFUNC_ABSTYPE: u32 = 0b0100 << 18;
const EXTERN_ABSTYPE: u32 = 0b0011 << 18;
const NOEXTERN_ABSTYPE: u32 = 0b0010 << 18;
const EXN_ABSTYPE: u32 = 0b0001 << 18;
const NONE_ABSTYPE: u32 = 0b0000 << 18;
// The `index` is valid only when `concrete == 1`.
const INDEX_MASK: u32 = (1 << 22) - 1;
/// A nullable untyped function reference aka `(ref null func)` aka
/// `funcref` aka `anyfunc`.
pub const FUNCREF: Self = RefType::FUNC.nullable();
/// A nullable reference to an extern object aka `(ref null extern)` aka
/// `externref`.
pub const EXTERNREF: Self = RefType::EXTERN.nullable();
/// A nullable reference to any object aka `(ref null any)` aka `anyref`.
pub const ANYREF: Self = RefType::ANY.nullable();
/// A nullable reference to no object aka `(ref null none)` aka `nullref`.
pub const NULLREF: Self = RefType::NONE.nullable();
/// A nullable reference to a noextern object aka `(ref null noextern)` aka
/// `nullexternref`.
pub const NULLEXTERNREF: Self = RefType::NOEXTERN.nullable();
/// A nullable reference to a nofunc object aka `(ref null nofunc)` aka
/// `nullfuncref`.
pub const NULLFUNCREF: Self = RefType::NOFUNC.nullable();
/// A nullable reference to an eq object aka `(ref null eq)` aka `eqref`.
pub const EQREF: Self = RefType::EQ.nullable();
/// A nullable reference to a struct aka `(ref null struct)` aka
/// `structref`.
pub const STRUCTREF: Self = RefType::STRUCT.nullable();
/// A nullable reference to an array aka `(ref null array)` aka `arrayref`.
pub const ARRAYREF: Self = RefType::ARRAY.nullable();
/// A nullable reference to an i31 object aka `(ref null i31)` aka `i31ref`.
pub const I31REF: Self = RefType::I31.nullable();
/// A nullable reference to an exception object aka `(ref null exn)` aka
/// `exnref`.
pub const EXNREF: Self = RefType::EXN.nullable();
/// A non-nullable untyped function reference aka `(ref func)`.
pub const FUNC: Self = RefType::from_u32(Self::FUNC_ABSTYPE);
/// A non-nullable reference to an extern object aka `(ref extern)`.
pub const EXTERN: Self = RefType::from_u32(Self::EXTERN_ABSTYPE);
/// A non-nullable reference to any object aka `(ref any)`.
pub const ANY: Self = RefType::from_u32(Self::ANY_ABSTYPE);
/// A non-nullable reference to no object aka `(ref none)`.
pub const NONE: Self = RefType::from_u32(Self::NONE_ABSTYPE);
/// A non-nullable reference to a noextern object aka `(ref noextern)`.
pub const NOEXTERN: Self = RefType::from_u32(Self::NOEXTERN_ABSTYPE);
/// A non-nullable reference to a nofunc object aka `(ref nofunc)`.
pub const NOFUNC: Self = RefType::from_u32(Self::NOFUNC_ABSTYPE);
/// A non-nullable reference to an eq object aka `(ref eq)`.
pub const EQ: Self = RefType::from_u32(Self::EQ_ABSTYPE);
/// A non-nullable reference to a struct aka `(ref struct)`.
pub const STRUCT: Self = RefType::from_u32(Self::STRUCT_ABSTYPE);
/// A non-nullable reference to an array aka `(ref array)`.
pub const ARRAY: Self = RefType::from_u32(Self::ARRAY_ABSTYPE);
/// A non-nullable reference to an i31 object aka `(ref i31)`.
pub const I31: Self = RefType::from_u32(Self::I31_ABSTYPE);
/// A non-nullable reference to an exn object aka `(ref exn)`.
pub const EXN: Self = RefType::from_u32(Self::EXN_ABSTYPE);
const fn can_represent_type_index(index: u32) -> bool {
index & Self::INDEX_MASK == index
}
const fn u24_to_u32(bytes: [u8; 3]) -> u32 {
let expanded_bytes = [bytes[0], bytes[1], bytes[2], 0];
u32::from_le_bytes(expanded_bytes)
}
const fn u32_to_u24(x: u32) -> [u8; 3] {
let bytes = x.to_le_bytes();
debug_assert!(bytes[3] == 0);
[bytes[0], bytes[1], bytes[2]]
}
#[inline]
const fn as_u32(&self) -> u32 {
Self::u24_to_u32(self.0)
}
#[inline]
const fn from_u32(x: u32) -> Self {
debug_assert!(x & (0b11111111 << 24) == 0);
// Either concrete or it must be a known abstract type.
debug_assert!(
x & Self::CONCRETE_BIT != 0
|| matches!(
x & Self::ABSTYPE_MASK,
Self::ANY_ABSTYPE
| Self::EQ_ABSTYPE
| Self::I31_ABSTYPE
| Self::STRUCT_ABSTYPE
| Self::ARRAY_ABSTYPE
| Self::FUNC_ABSTYPE
| Self::NOFUNC_ABSTYPE
| Self::EXTERN_ABSTYPE
| Self::NOEXTERN_ABSTYPE
| Self::NONE_ABSTYPE
| Self::EXN_ABSTYPE
)
);
RefType(Self::u32_to_u24(x))
}
/// Create a reference to a concrete Wasm-defined type at the given
/// index.
///
/// Returns `None` when the type index is beyond this crate's
/// implementation limits and therefore is not representable.
pub fn concrete(nullable: bool, index: PackedIndex) -> Self {
let index: u32 = PackedIndex::to_u32(index);
debug_assert!(Self::can_represent_type_index(index));
let nullable32 = Self::NULLABLE_BIT * nullable as u32;
RefType::from_u32(nullable32 | Self::CONCRETE_BIT | index)
}
/// Create a new `RefType`.
///
/// Returns `None` when the heap type's type index (if any) is
/// beyond this crate's implementation limits and therfore is not
/// representable.
pub fn new(nullable: bool, heap_type: HeapType) -> Option<Self> {
let nullable32 = Self::NULLABLE_BIT * (nullable as u32);
match heap_type {
HeapType::Concrete(index) => Some(RefType::concrete(nullable, index.pack()?)),
HeapType::Func => Some(Self::from_u32(nullable32 | Self::FUNC_ABSTYPE)),
HeapType::Extern => Some(Self::from_u32(nullable32 | Self::EXTERN_ABSTYPE)),
HeapType::Any => Some(Self::from_u32(nullable32 | Self::ANY_ABSTYPE)),
HeapType::None => Some(Self::from_u32(nullable32 | Self::NONE_ABSTYPE)),
HeapType::NoExtern => Some(Self::from_u32(nullable32 | Self::NOEXTERN_ABSTYPE)),
HeapType::NoFunc => Some(Self::from_u32(nullable32 | Self::NOFUNC_ABSTYPE)),
HeapType::Eq => Some(Self::from_u32(nullable32 | Self::EQ_ABSTYPE)),
HeapType::Struct => Some(Self::from_u32(nullable32 | Self::STRUCT_ABSTYPE)),
HeapType::Array => Some(Self::from_u32(nullable32 | Self::ARRAY_ABSTYPE)),
HeapType::I31 => Some(Self::from_u32(nullable32 | Self::I31_ABSTYPE)),
HeapType::Exn => Some(Self::from_u32(nullable32 | Self::EXN_ABSTYPE)),
}
}
/// Compute the [type difference] between the two given ref types.
///
/// [type difference]: https://webassembly.github.io/gc/core/valid/conventions.html#aux-reftypediff
pub fn difference(a: RefType, b: RefType) -> RefType {
RefType::new(
if b.is_nullable() {
false
} else {
a.is_nullable()
},
a.heap_type(),
)
.unwrap()
}
/// Is this a reference to an concrete type?
pub const fn is_concrete_type_ref(&self) -> bool {
self.as_u32() & Self::CONCRETE_BIT != 0
}
/// If this is a reference to a concrete Wasm-defined type, get its
/// type index.
pub fn type_index(&self) -> Option<PackedIndex> {
if self.is_concrete_type_ref() {
let index = self.as_u32() & Self::INDEX_MASK;
Some(PackedIndex::unchecked_from_u32(index))
} else {
None
}
}
const fn abstype(&self) -> u32 {
debug_assert!(!self.is_concrete_type_ref());
self.as_u32() & Self::ABSTYPE_MASK
}
/// Is this the abstract untyped function reference type aka `(ref
/// null func)` aka `funcref` aka `anyfunc`?
pub const fn is_func_ref(&self) -> bool {
!self.is_concrete_type_ref() && self.abstype() == Self::FUNC_ABSTYPE
}
/// Is this the abstract external reference type aka `(ref null
/// extern)` aka `externref`?
pub const fn is_extern_ref(&self) -> bool {
!self.is_concrete_type_ref() && self.abstype() == Self::EXTERN_ABSTYPE
}
/// Is this the abstract untyped array refrence type aka `(ref null
/// array)` aka `arrayref`?
pub const fn is_array_ref(&self) -> bool {
!self.is_concrete_type_ref() && self.abstype() == Self::ARRAY_ABSTYPE
}
/// Is this the abstract untyped struct reference type aka `(ref
/// null struct)` aka `structref`?
pub const fn is_struct_ref(&self) -> bool {
!self.is_concrete_type_ref() && self.abstype() == Self::STRUCT_ABSTYPE
}
/// Is this ref type nullable?
pub const fn is_nullable(&self) -> bool {
self.as_u32() & Self::NULLABLE_BIT != 0
}
/// Get the non-nullable version of this ref type.
pub const fn as_non_null(&self) -> Self {
Self::from_u32(self.as_u32() & !Self::NULLABLE_BIT)
}
/// Get the nullable version of this ref type.
pub const fn nullable(&self) -> Self {
Self::from_u32(self.as_u32() | Self::NULLABLE_BIT)
}
/// Get the heap type that this is a reference to.
pub fn heap_type(&self) -> HeapType {
let s = self.as_u32();
if self.is_concrete_type_ref() {
HeapType::Concrete(self.type_index().unwrap().unpack())
} else {
match s & Self::ABSTYPE_MASK {
Self::FUNC_ABSTYPE => HeapType::Func,
Self::EXTERN_ABSTYPE => HeapType::Extern,
Self::ANY_ABSTYPE => HeapType::Any,
Self::NONE_ABSTYPE => HeapType::None,
Self::NOEXTERN_ABSTYPE => HeapType::NoExtern,
Self::NOFUNC_ABSTYPE => HeapType::NoFunc,
Self::EQ_ABSTYPE => HeapType::Eq,
Self::STRUCT_ABSTYPE => HeapType::Struct,
Self::ARRAY_ABSTYPE => HeapType::Array,
Self::I31_ABSTYPE => HeapType::I31,
Self::EXN_ABSTYPE => HeapType::Exn,
_ => unreachable!(),
}
}
}
// Note that this is similar to `Display for RefType` except that it has
// the indexes stubbed out.
pub(crate) fn wat(&self) -> &'static str {
match (self.is_nullable(), self.heap_type()) {
(true, HeapType::Func) => "funcref",
(true, HeapType::Extern) => "externref",
(true, HeapType::Concrete(_)) => "(ref null $type)",
(true, HeapType::Any) => "anyref",
(true, HeapType::None) => "nullref",
(true, HeapType::NoExtern) => "nullexternref",
(true, HeapType::NoFunc) => "nullfuncref",
(true, HeapType::Eq) => "eqref",
(true, HeapType::Struct) => "structref",
(true, HeapType::Array) => "arrayref",
(true, HeapType::I31) => "i31ref",
(true, HeapType::Exn) => "exnref",
(false, HeapType::Func) => "(ref func)",
(false, HeapType::Extern) => "(ref extern)",
(false, HeapType::Concrete(_)) => "(ref $type)",
(false, HeapType::Any) => "(ref any)",
(false, HeapType::None) => "(ref none)",
(false, HeapType::NoExtern) => "(ref noextern)",
(false, HeapType::NoFunc) => "(ref nofunc)",
(false, HeapType::Eq) => "(ref eq)",
(false, HeapType::Struct) => "(ref struct)",
(false, HeapType::Array) => "(ref array)",
(false, HeapType::I31) => "(ref i31)",
(false, HeapType::Exn) => "(ref exn)",
}
}
}
/// A heap type.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub enum HeapType {
/// A concrete, user-defined type.
///
/// Introduced in the function-references proposal.
Concrete(UnpackedIndex),
/// The abstract, untyped (any) function.
///
/// Introduced in the references-types proposal.
Func,
/// The abstract, external heap type.
///
/// Introduced in the references-types proposal.
Extern,
/// The abstract `any` heap type.
///
/// The common supertype (a.k.a. top) of all internal types.
///
/// Introduced in the GC proposal.
Any,
/// The abstract `none` heap type.
///
/// The common subtype (a.k.a. bottom) of all internal types.
///
/// Introduced in the GC proposal.
None,
/// The abstract `noextern` heap type.
///
/// The common subtype (a.k.a. bottom) of all external types.
///
/// Introduced in the GC proposal.
NoExtern,
/// The abstract `nofunc` heap type.
///
/// The common subtype (a.k.a. bottom) of all function types.
///
/// Introduced in the GC proposal.
NoFunc,
/// The abstract `eq` heap type.
///
/// The common supertype of all heap types on which the `ref.eq`
/// instruction is allowed.
///
/// Introduced in the GC proposal.
Eq,
/// The abstract `struct` heap type.
///
/// The common supertype of all struct types.
///
/// Introduced in the GC proposal.
Struct,
/// The abstract `array` heap type.
///
/// The common supertype of all array types.
///
/// Introduced in the GC proposal.
Array,
/// The abstract `i31` heap type.
///
/// It is not expected that Wasm runtimes actually store these
/// values on the heap, but unbox them inline into the `i31ref`s
/// themselves instead.
///
/// Introduced in the GC proposal.
I31,
/// The abstraction `exception` heap type.
///
/// Introduced in the exception-handling proposal.
Exn,
}
impl ValType {
pub(crate) fn is_valtype_byte(byte: u8) -> bool {
match byte {
0x7F | 0x7E | 0x7D | 0x7C | 0x7B | 0x70 | 0x6F | 0x64 | 0x63 | 0x6E | 0x71 | 0x72
| 0x73 | 0x6D | 0x6B | 0x6A | 0x6C | 0x69 => true,
_ => false,
}
}
}
impl<'a> FromReader<'a> for StorageType {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
match reader.peek()? {
0x78 => {
reader.position += 1;
Ok(StorageType::I8)
}
0x77 => {
reader.position += 1;
Ok(StorageType::I16)
}
_ => Ok(StorageType::Val(reader.read()?)),
}
}
}
impl<'a> FromReader<'a> for ValType {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
match reader.peek()? {
0x7F => {
reader.position += 1;
Ok(ValType::I32)
}
0x7E => {
reader.position += 1;
Ok(ValType::I64)
}
0x7D => {
reader.position += 1;
Ok(ValType::F32)
}
0x7C => {
reader.position += 1;
Ok(ValType::F64)
}
0x7B => {
reader.position += 1;
Ok(ValType::V128)
}
0x70 | 0x6F | 0x64 | 0x63 | 0x6E | 0x71 | 0x72 | 0x73 | 0x6D | 0x6B | 0x6A | 0x6C
| 0x69 => Ok(ValType::Ref(reader.read()?)),
_ => bail!(reader.original_position(), "invalid value type"),
}
}
}
impl<'a> FromReader<'a> for RefType {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
match reader.read()? {
0x70 => Ok(RefType::FUNC.nullable()),
0x6F => Ok(RefType::EXTERN.nullable()),
0x6E => Ok(RefType::ANY.nullable()),
0x71 => Ok(RefType::NONE.nullable()),
0x72 => Ok(RefType::NOEXTERN.nullable()),
0x73 => Ok(RefType::NOFUNC.nullable()),
0x6D => Ok(RefType::EQ.nullable()),
0x6B => Ok(RefType::STRUCT.nullable()),
0x6A => Ok(RefType::ARRAY.nullable()),
0x6C => Ok(RefType::I31.nullable()),
0x69 => Ok(RefType::EXN.nullable()),
byte @ (0x63 | 0x64) => {
let nullable = byte == 0x63;
let pos = reader.original_position();
RefType::new(nullable, reader.read()?)
.ok_or_else(|| crate::BinaryReaderError::new("type index too large", pos))
}
_ => bail!(reader.original_position(), "malformed reference type"),
}
}
}
impl<'a> FromReader<'a> for HeapType {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
match reader.peek()? {
0x70 => {
reader.position += 1;
Ok(HeapType::Func)
}
0x6F => {
reader.position += 1;
Ok(HeapType::Extern)
}
0x6E => {
reader.position += 1;
Ok(HeapType::Any)
}
0x71 => {
reader.position += 1;
Ok(HeapType::None)
}
0x72 => {
reader.position += 1;
Ok(HeapType::NoExtern)
}
0x73 => {
reader.position += 1;
Ok(HeapType::NoFunc)
}
0x6D => {
reader.position += 1;
Ok(HeapType::Eq)
}
0x6B => {
reader.position += 1;
Ok(HeapType::Struct)
}
0x6A => {
reader.position += 1;
Ok(HeapType::Array)
}
0x6C => {
reader.position += 1;
Ok(HeapType::I31)
}
0x69 => {
reader.position += 1;
Ok(HeapType::Exn)
}
_ => {
let idx = match u32::try_from(reader.read_var_s33()?) {
Ok(idx) => idx,
Err(_) => {
bail!(reader.original_position(), "invalid indexed ref heap type");
}
};
let idx = PackedIndex::from_module_index(idx).ok_or_else(|| {
BinaryReaderError::new(
"type index greater than implementation limits",
reader.original_position(),
)
})?;
Ok(HeapType::Concrete(idx.unpack()))
}
}
}
}
/// Represents a table's type.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub struct TableType {
/// The table's element type.
pub element_type: RefType,
/// Initial size of this table, in elements.
pub initial: u32,
/// Optional maximum size of the table, in elements.
pub maximum: Option<u32>,
}
/// Represents a memory's type.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub struct MemoryType {
/// Whether or not this is a 64-bit memory, using i64 as an index. If this
/// is false it's a 32-bit memory using i32 as an index.
///
/// This is part of the memory64 proposal in WebAssembly.
pub memory64: bool,
/// Whether or not this is a "shared" memory, indicating that it should be
/// send-able across threads and the `maximum` field is always present for
/// valid types.
///
/// This is part of the threads proposal in WebAssembly.
pub shared: bool,
/// Initial size of this memory, in wasm pages.
///
/// For 32-bit memories (when `memory64` is `false`) this is guaranteed to
/// be at most `u32::MAX` for valid types.
pub initial: u64,
/// Optional maximum size of this memory, in wasm pages.
///
/// For 32-bit memories (when `memory64` is `false`) this is guaranteed to
/// be at most `u32::MAX` for valid types. This field is always present for
/// valid wasm memories when `shared` is `true`.
pub maximum: Option<u64>,
}
impl MemoryType {
/// Gets the index type for the memory.
pub fn index_type(&self) -> ValType {
if self.memory64 {
ValType::I64
} else {
ValType::I32
}
}
}
/// Represents a global's type.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub struct GlobalType {
/// The global's type.
pub content_type: ValType,
/// Whether or not the global is mutable.
pub mutable: bool,
}
/// Represents a tag kind.
#[derive(Clone, Copy, Debug)]
pub enum TagKind {
/// The tag is an exception type.
Exception,
}
/// A tag's type.
#[derive(Clone, Copy, Debug)]
pub struct TagType {
/// The kind of tag
pub kind: TagKind,
/// The function type this tag uses.
pub func_type_idx: u32,
}
/// A reader for the type section of a WebAssembly module.
pub type TypeSectionReader<'a> = SectionLimited<'a, RecGroup>;
impl<'a> TypeSectionReader<'a> {
/// Returns an iterator over this type section which will only yield
/// function types and any usage of GC types from the GC proposal will
/// be translated into an error.
pub fn into_iter_err_on_gc_types(self) -> impl Iterator<Item = Result<FuncType>> + 'a {
self.into_iter_with_offsets().map(|item| {
let (offset, group) = item?;
let mut types = group.into_types();
let ty = match (types.next(), types.next()) {
(Some(ty), None) => ty,
_ => bail!(offset, "gc proposal not supported"),
};
if !ty.is_final || ty.supertype_idx.is_some() {
bail!(offset, "gc proposal not supported");
}
match ty.composite_type {
CompositeType::Func(f) => Ok(f),
CompositeType::Array(_) | CompositeType::Struct(_) => {
bail!(offset, "gc proposal not supported");
}
}
})
}
}
impl<'a> FromReader<'a> for CompositeType {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
read_composite_type(reader.read_u8()?, reader)
}
}
fn read_composite_type(
opcode: u8,
reader: &mut BinaryReader,
) -> Result<CompositeType, BinaryReaderError> {
Ok(match opcode {
0x60 => CompositeType::Func(reader.read()?),
0x5e => CompositeType::Array(reader.read()?),
0x5f => CompositeType::Struct(reader.read()?),
x => return reader.invalid_leading_byte(x, "type"),
})
}
impl<'a> FromReader<'a> for RecGroup {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
match reader.peek()? {
0x4e => {
reader.read_u8()?;
let mut iter = reader.read_iter(MAX_WASM_TYPES, "rec group types")?;
let mut types = Vec::with_capacity(iter.size_hint().0);
let mut offset = iter.reader.original_position();
while let Some(ty) = iter.next() {
types.push((offset, ty?));
offset = iter.reader.original_position();
}
Ok(RecGroup::explicit(types))
}
_ => Ok(RecGroup::implicit(
reader.original_position(),
reader.read()?,
)),
}
}
}
impl<'a> FromReader<'a> for SubType {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
let pos = reader.original_position();
Ok(match reader.read_u8()? {
opcode @ (0x4f | 0x50) => {
let idx_iter = reader.read_iter(MAX_WASM_SUPERTYPES, "supertype idxs")?;
let idxs = idx_iter.collect::<Result<Vec<u32>>>()?;
if idxs.len() > 1 {
return Err(BinaryReaderError::new(
"multiple supertypes not supported",
pos,
));
}
let supertype_idx = idxs
.first()
.copied()
.map(|idx| {
PackedIndex::from_module_index(idx).ok_or_else(|| {
BinaryReaderError::new(
"type index greater than implementation limits",
reader.original_position(),
)
})
})
.transpose()?;
SubType {
is_final: opcode == 0x4f,
supertype_idx,
composite_type: read_composite_type(reader.read_u8()?, reader)?,
}
}
opcode => SubType {
is_final: true,
supertype_idx: None,
composite_type: read_composite_type(opcode, reader)?,
},
})
}
}
impl<'a> FromReader<'a> for FuncType {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
let mut params_results = reader
.read_iter(MAX_WASM_FUNCTION_PARAMS, "function params")?
.collect::<Result<Vec<_>>>()?;
let len_params = params_results.len();
let results = reader.read_iter(MAX_WASM_FUNCTION_RETURNS, "function returns")?;
params_results.reserve(results.size_hint().0);
for result in results {
params_results.push(result?);
}
Ok(FuncType::from_raw_parts(params_results.into(), len_params))
}
}
impl<'a> FromReader<'a> for FieldType {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
let element_type = reader.read()?;
let mutable = reader.read_u8()?;
Ok(FieldType {
element_type,
mutable: match mutable {
0 => false,
1 => true,
_ => bail!(
reader.original_position(),
"malformed mutability byte for field type"
),
},
})
}
}
impl<'a> FromReader<'a> for ArrayType {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
Ok(ArrayType(FieldType::from_reader(reader)?))
}
}
impl<'a> FromReader<'a> for StructType {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
let fields = reader.read_iter(MAX_WASM_STRUCT_FIELDS, "struct fields")?;
Ok(StructType {
fields: fields.collect::<Result<_>>()?,
})
}
}