T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Deduplicate some size/align calculations (#4658)

Browse Source 
This commit is an effort to reduce the amount of complexity around
managing the size/alignment calculations of types in the canonical ABI.
Previously the logic for the size/alignment of a type was spread out
across a number of locations. While each individual calculation is not
really the most complicated thing in the world having the duplication in
so many places was constantly worrying me.

I've opted in this commit to centralize all of this within the runtime
at least, and now there's only one "duplicate" of this information in
the fuzzing infrastructure which is to some degree less important to
deduplicate. This commit introduces a new `CanonicalAbiInfo` type to
house all abi size/align information for both memory32 and memory64.
This new type is then used pervasively throughout fused adapter
compilation, dynamic `Val` management, and typed functions. This type
was also able to reduce the complexity of the macro-generated code
meaning that even `wasmtime-component-macro` is performing less math
than it was before.

One other major feature of this commit is that this ABI information is
now saved within a `ComponentTypes` structure. This avoids recursive
querying of size/align information frequently and instead effectively
caching it. This was a worry I had for the fused adapter compiler which
frequently sought out size/align information and would recursively
descend each type tree each time. The `fact-valid-module` fuzzer is now
nearly 10x faster in terms of iterations/s which I suspect is due to
this caching.
This commit is contained in:
Alex Crichton
2022-08-09 14:52:20 -05:00
committed by GitHub
parent d5de91b953
commit bd70dbebbd
15 changed files with 845 additions and 763 deletions
Download Patch File Download Diff File Expand all files Collapse all files

87
crates/component-macro/src/lib.rs
View File

@@ -298,7 +298,7 @@ fn expand_record_for_component_type(
let mut lower_generic_params = TokenStream::new();
let mut lower_generic_args = TokenStream::new();
let mut lower_field_declarations = TokenStream::new();
let mut sizes = TokenStream::new();
let mut abi_list = TokenStream::new();
let mut unique_types = HashSet::new();
for (index, syn::Field { ident, ty, .. }) in fields.iter().enumerate() {
@@ -309,24 +309,13 @@ fn expand_record_for_component_type(
lower_field_declarations.extend(quote!(#ident: #generic,));
sizes.extend(quote!(
size = #internal::align_to(size, <#ty as wasmtime::component::ComponentType>::ALIGN32);
size += <#ty as wasmtime::component::ComponentType>::SIZE32;
abi_list.extend(quote!(
<#ty as wasmtime::component::ComponentType>::ABI,
));
unique_types.insert(ty);
}
let alignments = unique_types
.into_iter()
.map(|ty| {
let align = quote!(<#ty as wasmtime::component::ComponentType>::ALIGN32);
quote!(if #align > align {
align = #align;
})
})
.collect::<TokenStream>();
let generics = add_trait_bounds(generics, parse_quote!(wasmtime::component::ComponentType));
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
let lower = format_ident!("Lower{}", name);
@@ -358,17 +347,8 @@ fn expand_record_for_component_type(
unsafe impl #impl_generics wasmtime::component::ComponentType for #name #ty_generics #where_clause {
type Lower = #lower <#lower_generic_args>;
const SIZE32: usize = {
let mut size = 0;
#sizes
#internal::align_to(size, Self::ALIGN32)
};
const ALIGN32: u32 = {
let mut align = 1;
#alignments
align
};
const ABI: #internal::CanonicalAbiInfo =
#internal::CanonicalAbiInfo::record_static(&[#abi_list]);
#[inline]
fn typecheck(
@@ -429,7 +409,7 @@ impl Expander for LiftExpander {
loads.extend(quote!(#ident: <#ty as wasmtime::component::Lift>::load(
memory,
&bytes
[#internal::next_field::<#ty>(&mut offset)..]
[<#ty as wasmtime::component::ComponentType>::ABI.next_field32_size(&mut offset)..]
[..<#ty as wasmtime::component::ComponentType>::SIZE32]
)?,));
}
@@ -514,8 +494,6 @@ impl Expander for LiftExpander {
DiscriminantSize::Size4 => quote!(u32::from_le_bytes(bytes[0..4].try_into()?)),
};
let payload_offset = usize::from(discriminant_size);
let expanded = quote! {
unsafe impl #impl_generics wasmtime::component::Lift for #name #ty_generics #where_clause {
#[inline]
@@ -535,7 +513,8 @@ impl Expander for LiftExpander {
let align = <Self as wasmtime::component::ComponentType>::ALIGN32;
debug_assert!((bytes.as_ptr() as usize) % (align as usize) == 0);
let discrim = #from_bytes;
let payload = &bytes[#internal::align_to(#payload_offset, align)..];
let payload_offset = <Self as #internal::ComponentVariant>::PAYLOAD_OFFSET32;
let payload = &bytes[payload_offset..];
Ok(match discrim {
#loads
discrim => #internal::anyhow::bail!("unexpected discriminant: {}", discrim),
@@ -575,7 +554,9 @@ impl Expander for LowerExpander {
)?;));
stores.extend(quote!(wasmtime::component::Lower::store(
&self.#ident, memory, #internal::next_field::<#ty>(&mut offset)
&self.#ident,
memory,
<#ty as wasmtime::component::ComponentType>::ABI.next_field32_size(&mut offset),
)?;));
}
@@ -640,10 +621,7 @@ impl Expander for LowerExpander {
lower = quote!(value.lower(store, options, #internal::map_maybe_uninit!(dst.payload.#ident)));
store = quote!(value.store(
memory,
offset + #internal::align_to(
#discriminant_size,
<Self as wasmtime::component::ComponentType>::ALIGN32
)
offset + <Self as #internal::ComponentVariant>::PAYLOAD_OFFSET32,
));
} else {
pattern = quote!(Self::#ident);
@@ -749,7 +727,7 @@ impl Expander for ComponentTypeExpander {
&self,
name: &syn::Ident,
generics: &syn::Generics,
discriminant_size: DiscriminantSize,
_discriminant_size: DiscriminantSize,
cases: &[VariantCase],
style: VariantStyle,
) -> Result<TokenStream> {
@@ -760,7 +738,7 @@ impl Expander for ComponentTypeExpander {
let mut lower_payload_generic_args = TokenStream::new();
let mut lower_payload_case_declarations = TokenStream::new();
let mut lower_generic_args = TokenStream::new();
let mut sizes = TokenStream::new();
let mut abi_list = TokenStream::new();
let mut unique_types = HashSet::new();
for (index, VariantCase { attrs, ident, ty }) in cases.iter().enumerate() {
@@ -776,12 +754,7 @@ impl Expander for ComponentTypeExpander {
let name = rename.unwrap_or_else(|| Literal::string(&ident.to_string()));
if let Some(ty) = ty {
sizes.extend({
let size = quote!(<#ty as wasmtime::component::ComponentType>::SIZE32);
quote!(if #size > size {
size = #size;
})
});
abi_list.extend(quote!(<#ty as wasmtime::component::ComponentType>::ABI,));
case_names_and_checks.extend(match style {
VariantStyle::Variant => {
@@ -808,6 +781,7 @@ impl Expander for ComponentTypeExpander {
unique_types.insert(ty);
} else {
abi_list.extend(quote!(<() as wasmtime::component::ComponentType>::ABI,));
case_names_and_checks.extend(match style {
VariantStyle::Variant => {
quote!((#name, <() as wasmtime::component::ComponentType>::typecheck),)
@@ -824,16 +798,6 @@ impl Expander for ComponentTypeExpander {
lower_payload_case_declarations.extend(quote!(_dummy: ()));
}
let alignments = unique_types
.into_iter()
.map(|ty| {
let align = quote!(<#ty as wasmtime::component::ComponentType>::ALIGN32);
quote!(if #align > align {
align = #align;
})
})
.collect::<TokenStream>();
let typecheck = match style {
VariantStyle::Variant => quote!(typecheck_variant),
VariantStyle::Union => quote!(typecheck_union),
@@ -844,7 +808,6 @@ impl Expander for ComponentTypeExpander {
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
let lower = format_ident!("Lower{}", name);
let lower_payload = format_ident!("LowerPayload{}", name);
let discriminant_size = u32::from(discriminant_size);
// You may wonder why we make the types of all the fields of the #lower struct and #lower_payload union
// generic. This is to work around a [normalization bug in
@@ -882,20 +845,12 @@ impl Expander for ComponentTypeExpander {
#internal::#typecheck(ty, types, &[#case_names_and_checks])
}
const SIZE32: usize = {
let mut size = 0;
#sizes
#internal::align_to(
#internal::align_to(#discriminant_size as usize, Self::ALIGN32) + size,
Self::ALIGN32
)
};
const ABI: #internal::CanonicalAbiInfo =
#internal::CanonicalAbiInfo::variant_static(&[#abi_list]);
}
const ALIGN32: u32 = {
let mut align = #discriminant_size;
#alignments
align
};
unsafe impl #impl_generics #internal::ComponentVariant for #name #ty_generics #where_clause {
const CASES: &'static [#internal::CanonicalAbiInfo] = &[#abi_list];
}
};