bjoernager/rust
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Auto merge of #119478 - bjorn3:no_serialize_specialization, r=wesleywiser

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Avoid specialization in the metadata serialization code

With the exception of a perf-only specialization for byte slices and byte vectors.

This uses the same trick of introducing a new trait and having the Encodable and Decodable derives add a bound to it as used for TyEncoder/TyDecoder. The new code is clearer about which encoder/decoder uses which impl and it reduces the dependency of rustc on specialization, making it easier to remove support for specialization entirely or turn it into a construct that is only allowed for perf optimizations if we decide to do this.
This commit is contained in:
bors 2024-01-06 09:56:00 +00:00
commit e21f4cd98f
24 changed files with 478 additions and 400 deletions
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18
compiler/rustc_ast/src/ast.rs
View file

@ -20,6 +20,7 @@
pub use crate::format::*;
pub use crate::util::parser::ExprPrecedence;
pub use rustc_span::AttrId;
pub use GenericArgs::*;
pub use UnsafeSource::*;
@ -30,7 +31,6 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::stack::ensure_sufficient_stack;
use rustc_data_structures::sync::Lrc;
use rustc_macros::HashStable_Generic;
use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
use rustc_span::source_map::{respan, Spanned};
use rustc_span::symbol::{kw, sym, Ident, Symbol};
use rustc_span::{ErrorGuaranteed, Span, DUMMY_SP};
@ -2682,22 +2682,6 @@ pub enum AttrStyle {
Inner,
}
rustc_index::newtype_index! {
#[orderable]
#[debug_format = "AttrId({})"]
pub struct AttrId {}
}
impl<S: Encoder> Encodable<S> for AttrId {
fn encode(&self, _s: &mut S) {}
}
impl<D: Decoder> Decodable<D> for AttrId {
default fn decode(_: &mut D) -> AttrId {
panic!("cannot decode `AttrId` with `{}`", std::any::type_name::<D>());
}
}
/// A list of attributes.
pub type AttrVec = ThinVec<Attribute>;

8
compiler/rustc_ast/src/tokenstream.rs
View file

@ -21,8 +21,8 @@ use crate::AttrVec;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::sync::{self, Lrc};
use rustc_macros::HashStable_Generic;
use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
use rustc_span::{sym, Span, Symbol, DUMMY_SP};
use rustc_serialize::{Decodable, Encodable};
use rustc_span::{sym, Span, SpanDecoder, SpanEncoder, Symbol, DUMMY_SP};
use smallvec::{smallvec, SmallVec};
use std::borrow::Cow;
@ -150,14 +150,14 @@ impl fmt::Debug for LazyAttrTokenStream {
}
}
impl<S: Encoder> Encodable<S> for LazyAttrTokenStream {
impl<S: SpanEncoder> Encodable<S> for LazyAttrTokenStream {
fn encode(&self, s: &mut S) {
// Used by AST json printing.
Encodable::encode(&self.to_attr_token_stream(), s);
}
}
impl<D: Decoder> Decodable<D> for LazyAttrTokenStream {
impl<D: SpanDecoder> Decodable<D> for LazyAttrTokenStream {
fn decode(_d: &mut D) -> Self {
panic!("Attempted to decode LazyAttrTokenStream");
}