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-rw-r--r--compiler/rustc_macros/src/serialize.rs224
1 files changed, 224 insertions, 0 deletions
diff --git a/compiler/rustc_macros/src/serialize.rs b/compiler/rustc_macros/src/serialize.rs
new file mode 100644
index 000000000..82e6972d0
--- /dev/null
+++ b/compiler/rustc_macros/src/serialize.rs
@@ -0,0 +1,224 @@
+use proc_macro2::TokenStream;
+use quote::{quote, quote_spanned};
+use syn::parse_quote;
+use syn::spanned::Spanned;
+
+pub fn type_decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+ let decoder_ty = quote! { __D };
+ if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
+ s.add_impl_generic(parse_quote! { 'tcx });
+ }
+ s.add_impl_generic(parse_quote! {#decoder_ty: ::rustc_type_ir::codec::TyDecoder<I = ::rustc_middle::ty::TyCtxt<'tcx>>});
+ s.add_bounds(synstructure::AddBounds::Generics);
+
+ decodable_body(s, decoder_ty)
+}
+
+pub fn meta_decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+ if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
+ s.add_impl_generic(parse_quote! { 'tcx });
+ }
+ s.add_impl_generic(parse_quote! { '__a });
+ let decoder_ty = quote! { DecodeContext<'__a, 'tcx> };
+ s.add_bounds(synstructure::AddBounds::Generics);
+
+ decodable_body(s, decoder_ty)
+}
+
+pub fn decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+ let decoder_ty = quote! { __D };
+ s.add_impl_generic(parse_quote! {#decoder_ty: ::rustc_serialize::Decoder});
+ s.add_bounds(synstructure::AddBounds::Generics);
+
+ decodable_body(s, decoder_ty)
+}
+
+fn decodable_body(
+ s: synstructure::Structure<'_>,
+ decoder_ty: TokenStream,
+) -> proc_macro2::TokenStream {
+ if let syn::Data::Union(_) = s.ast().data {
+ panic!("cannot derive on union")
+ }
+ let ty_name = s.ast().ident.to_string();
+ let decode_body = match s.variants() {
+ [vi] => vi.construct(|field, _index| decode_field(field)),
+ variants => {
+ let match_inner: TokenStream = variants
+ .iter()
+ .enumerate()
+ .map(|(idx, vi)| {
+ let construct = vi.construct(|field, _index| decode_field(field));
+ quote! { #idx => { #construct } }
+ })
+ .collect();
+ let message = format!(
+ "invalid enum variant tag while decoding `{}`, expected 0..{}",
+ ty_name,
+ variants.len()
+ );
+ quote! {
+ match ::rustc_serialize::Decoder::read_usize(__decoder) {
+ #match_inner
+ _ => panic!(#message),
+ }
+ }
+ }
+ };
+
+ s.bound_impl(
+ quote!(::rustc_serialize::Decodable<#decoder_ty>),
+ quote! {
+ fn decode(__decoder: &mut #decoder_ty) -> Self {
+ #decode_body
+ }
+ },
+ )
+}
+
+fn decode_field(field: &syn::Field) -> proc_macro2::TokenStream {
+ let field_span = field.ident.as_ref().map_or(field.ty.span(), |ident| ident.span());
+
+ let decode_inner_method = if let syn::Type::Reference(_) = field.ty {
+ quote! { ::rustc_middle::ty::codec::RefDecodable::decode }
+ } else {
+ quote! { ::rustc_serialize::Decodable::decode }
+ };
+ let __decoder = quote! { __decoder };
+ // Use the span of the field for the method call, so
+ // that backtraces will point to the field.
+ quote_spanned! {field_span=> #decode_inner_method(#__decoder) }
+}
+
+pub fn type_encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+ if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
+ s.add_impl_generic(parse_quote! {'tcx});
+ }
+ let encoder_ty = quote! { __E };
+ s.add_impl_generic(parse_quote! {#encoder_ty: ::rustc_type_ir::codec::TyEncoder<I = ::rustc_middle::ty::TyCtxt<'tcx>>});
+ s.add_bounds(synstructure::AddBounds::Generics);
+
+ encodable_body(s, encoder_ty, false)
+}
+
+pub fn meta_encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+ if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
+ s.add_impl_generic(parse_quote! {'tcx});
+ }
+ s.add_impl_generic(parse_quote! { '__a });
+ let encoder_ty = quote! { EncodeContext<'__a, 'tcx> };
+ s.add_bounds(synstructure::AddBounds::Generics);
+
+ encodable_body(s, encoder_ty, true)
+}
+
+pub fn encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+ let encoder_ty = quote! { __E };
+ s.add_impl_generic(parse_quote! { #encoder_ty: ::rustc_serialize::Encoder});
+ s.add_bounds(synstructure::AddBounds::Generics);
+
+ encodable_body(s, encoder_ty, false)
+}
+
+fn encodable_body(
+ mut s: synstructure::Structure<'_>,
+ encoder_ty: TokenStream,
+ allow_unreachable_code: bool,
+) -> proc_macro2::TokenStream {
+ if let syn::Data::Union(_) = s.ast().data {
+ panic!("cannot derive on union")
+ }
+
+ s.bind_with(|binding| {
+ // Handle the lack of a blanket reference impl.
+ if let syn::Type::Reference(_) = binding.ast().ty {
+ synstructure::BindStyle::Move
+ } else {
+ synstructure::BindStyle::Ref
+ }
+ });
+
+ let encode_body = match s.variants() {
+ [_] => {
+ let encode_inner = s.each_variant(|vi| {
+ vi.bindings()
+ .iter()
+ .map(|binding| {
+ let bind_ident = &binding.binding;
+ let result = quote! {
+ ::rustc_serialize::Encodable::<#encoder_ty>::encode(
+ #bind_ident,
+ __encoder,
+ );
+ };
+ result
+ })
+ .collect::<TokenStream>()
+ });
+ quote! {
+ match *self { #encode_inner }
+ }
+ }
+ _ => {
+ let mut variant_idx = 0usize;
+ let encode_inner = s.each_variant(|vi| {
+ let encode_fields: TokenStream = vi
+ .bindings()
+ .iter()
+ .map(|binding| {
+ let bind_ident = &binding.binding;
+ let result = quote! {
+ ::rustc_serialize::Encodable::<#encoder_ty>::encode(
+ #bind_ident,
+ __encoder,
+ );
+ };
+ result
+ })
+ .collect();
+
+ let result = if !vi.bindings().is_empty() {
+ quote! {
+ ::rustc_serialize::Encoder::emit_enum_variant(
+ __encoder,
+ #variant_idx,
+ |__encoder| { #encode_fields }
+ )
+ }
+ } else {
+ quote! {
+ ::rustc_serialize::Encoder::emit_fieldless_enum_variant::<#variant_idx>(
+ __encoder,
+ )
+ }
+ };
+ variant_idx += 1;
+ result
+ });
+ quote! {
+ match *self {
+ #encode_inner
+ }
+ }
+ }
+ };
+
+ let lints = if allow_unreachable_code {
+ quote! { #![allow(unreachable_code)] }
+ } else {
+ quote! {}
+ };
+
+ s.bound_impl(
+ quote!(::rustc_serialize::Encodable<#encoder_ty>),
+ quote! {
+ fn encode(
+ &self,
+ __encoder: &mut #encoder_ty,
+ ) {
+ #lints
+ #encode_body
+ }
+ },
+ )
+}