bjoernager/rust
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Avoid generating empty closures for fieldless enums

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For many enums, this avoids generating lots of tiny stubs that need to be
codegen'd and then inlined and removed by LLVM.
This commit is contained in:
Mark Rousskov 2021-10-12 10:43:39 -04:00
parent 65f3f8b220
commit 3228603cce
3 changed files with 46 additions and 7 deletions
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25
compiler/rustc_macros/src/serialize.rs
View file

@ -247,13 +247,24 @@ fn encodable_body(
})
.collect();
let result = quote! { ::rustc_serialize::Encoder::emit_enum_variant(
__encoder,
#variant_name,
#variant_idx,
#field_idx,
|__encoder| { ::std::result::Result::Ok({ #encode_fields }) }
) };
let result = if field_idx != 0 {
quote! {
::rustc_serialize::Encoder::emit_enum_variant(
__encoder,
#variant_name,
#variant_idx,
#field_idx,
|__encoder| { ::std::result::Result::Ok({ #encode_fields }) }
)
}
} else {
quote! {
::rustc_serialize::Encoder::emit_fieldless_enum_variant::<#variant_idx>(
__encoder,
#variant_name,
)
}
};
variant_idx += 1;
result
});