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Rollup merge of #98915 - nnethercote:clarify-deriving-code, r=Mark-Simulacrum

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Clarify deriving code

A number of clarifications to the deriving code.

r? ``@Mark-Simulacrum``
This commit is contained in:
Dylan DPC 2022-07-09 11:28:04 +05:30 committed by GitHub
commit 5e6812b597
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GPG Key ID: 4AEE18F83AFDEB23
11 changed files with 457 additions and 570 deletions
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6
compiler/rustc_builtin_macros/src/deriving/clone.rs
View File

@ -80,7 +80,7 @@ pub fn expand_deriving_clone(
name: sym::clone,
generics: Bounds::empty(),
explicit_self: true,
args: Vec::new(),
nonself_args: Vec::new(),
ret_ty: Self_,
attributes: attrs,
unify_fieldless_variants: false,
@ -160,8 +160,8 @@ fn cs_clone(
let ctor_path;
let all_fields;
let fn_path = cx.std_path(&[sym::clone, sym::Clone, sym::clone]);
let subcall = |cx: &mut ExtCtxt<'_>, field: &FieldInfo<'_>| {
let args = vec![cx.expr_addr_of(field.span, field.self_.clone())];
let subcall = |cx: &mut ExtCtxt<'_>, field: &FieldInfo| {
let args = vec![cx.expr_addr_of(field.span, field.self_expr.clone())];
cx.expr_call_global(field.span, fn_path.clone(), args)
};

2
compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs
View File

@ -32,7 +32,7 @@ pub fn expand_deriving_eq(
name: sym::assert_receiver_is_total_eq,
generics: Bounds::empty(),
explicit_self: true,
args: vec![],
nonself_args: vec![],
ret_ty: Unit,
attributes: attrs,
unify_fieldless_variants: true,

103
compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs
View File

@ -2,8 +2,7 @@ use crate::deriving::generic::ty::*;
use crate::deriving::generic::*;
use crate::deriving::path_std;
use rustc_ast::ptr::P;
use rustc_ast::{self as ast, MetaItem};
use rustc_ast::MetaItem;
use rustc_expand::base::{Annotatable, ExtCtxt};
use rustc_span::symbol::{sym, Ident};
use rustc_span::Span;
@ -28,7 +27,7 @@ pub fn expand_deriving_ord(
name: sym::cmp,
generics: Bounds::empty(),
explicit_self: true,
args: vec![(self_ref(), sym::other)],
nonself_args: vec![(self_ref(), sym::other)],
ret_ty: Path(path_std!(cmp::Ordering)),
attributes: attrs,
unify_fieldless_variants: true,
@ -40,84 +39,54 @@ pub fn expand_deriving_ord(
trait_def.expand(cx, mitem, item, push)
}
pub fn ordering_collapsed(
cx: &mut ExtCtxt<'_>,
span: Span,
self_arg_tags: &[Ident],
) -> P<ast::Expr> {
let lft = cx.expr_addr_of(span, cx.expr_ident(span, self_arg_tags[0]));
let rgt = cx.expr_addr_of(span, cx.expr_ident(span, self_arg_tags[1]));
let fn_cmp_path = cx.std_path(&[sym::cmp, sym::Ord, sym::cmp]);
cx.expr_call_global(span, fn_cmp_path, vec![lft, rgt])
}
pub fn cs_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> BlockOrExpr {
let test_id = Ident::new(sym::cmp, span);
let equals_path = cx.path_global(span, cx.std_path(&[sym::cmp, sym::Ordering, sym::Equal]));
let equal_path = cx.path_global(span, cx.std_path(&[sym::cmp, sym::Ordering, sym::Equal]));
let cmp_path = cx.std_path(&[sym::cmp, sym::Ord, sym::cmp]);
// Builds:
//
// match ::std::cmp::Ord::cmp(&self_field1, &other_field1) {
// ::std::cmp::Ordering::Equal =>
// match ::std::cmp::Ord::cmp(&self_field2, &other_field2) {
// ::std::cmp::Ordering::Equal => {
// ...
// match ::core::cmp::Ord::cmp(&self.x, &other.x) {
// ::std::cmp::Ordering::Equal =>
// ::core::cmp::Ord::cmp(&self.y, &other.y),
// cmp => cmp,
// }
// cmp => cmp
// },
// cmp => cmp
// }
//
let expr = cs_fold(
// foldr nests the if-elses correctly, leaving the first field
// as the outermost one, and the last as the innermost.
false,
|cx, span, old, self_f, other_fs| {
// match new {
// ::std::cmp::Ordering::Equal => old,
// cmp => cmp
// }
let new = {
let [other_f] = other_fs else {
cx.span_bug(span, "not exactly 2 arguments in `derive(Ord)`");
};
let args =
vec![cx.expr_addr_of(span, self_f), cx.expr_addr_of(span, other_f.clone())];
cx.expr_call_global(span, cmp_path.clone(), args)
};
let eq_arm = cx.arm(span, cx.pat_path(span, equals_path.clone()), old);
let neq_arm = cx.arm(span, cx.pat_ident(span, test_id), cx.expr_ident(span, test_id));
cx.expr_match(span, new, vec![eq_arm, neq_arm])
},
|cx, args| match args {
Some((span, self_f, other_fs)) => {
let new = {
let [other_f] = other_fs else {
cx.span_bug(span, "not exactly 2 arguments in `derive(Ord)`");
};
let args =
vec![cx.expr_addr_of(span, self_f), cx.expr_addr_of(span, other_f.clone())];
cx.expr_call_global(span, cmp_path.clone(), args)
};
new
}
None => cx.expr_path(equals_path.clone()),
},
Box::new(|cx, span, tag_tuple| {
if tag_tuple.len() != 2 {
cx.span_bug(span, "not exactly 2 arguments in `derive(Ord)`")
} else {
ordering_collapsed(cx, span, tag_tuple)
}
}),
cx,
span,
substr,
|cx, fold| match fold {
CsFold::Single(field) => {
let [other_expr] = &field.other_selflike_exprs[..] else {
cx.span_bug(field.span, "not exactly 2 arguments in `derive(Ord)`");
};
let args = vec![
cx.expr_addr_of(field.span, field.self_expr.clone()),
cx.expr_addr_of(field.span, other_expr.clone()),
];
cx.expr_call_global(field.span, cmp_path.clone(), args)
}
CsFold::Combine(span, expr1, expr2) => {
let eq_arm = cx.arm(span, cx.pat_path(span, equal_path.clone()), expr1);
let neq_arm =
cx.arm(span, cx.pat_ident(span, test_id), cx.expr_ident(span, test_id));
cx.expr_match(span, expr2, vec![eq_arm, neq_arm])
}
CsFold::Fieldless => cx.expr_path(equal_path.clone()),
CsFold::EnumNonMatching(span, tag_tuple) => {
if tag_tuple.len() != 2 {
cx.span_bug(span, "not exactly 2 arguments in `derive(Ord)`")
} else {
let lft = cx.expr_addr_of(span, cx.expr_ident(span, tag_tuple[0]));
let rgt = cx.expr_addr_of(span, cx.expr_ident(span, tag_tuple[1]));
let fn_cmp_path = cx.std_path(&[sym::cmp, sym::Ord, sym::cmp]);
cx.expr_call_global(span, fn_cmp_path, vec![lft, rgt])
}
}
},
);
BlockOrExpr::new_expr(expr)
}

38
compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs
View File

@ -2,8 +2,7 @@ use crate::deriving::generic::ty::*;
use crate::deriving::generic::*;
use crate::deriving::{path_local, path_std};
use rustc_ast::ptr::P;
use rustc_ast::{BinOpKind, Expr, MetaItem};
use rustc_ast::{BinOpKind, MetaItem};
use rustc_expand::base::{Annotatable, ExtCtxt};
use rustc_span::symbol::sym;
use rustc_span::Span;
@ -23,33 +22,22 @@ pub fn expand_deriving_partial_eq(
combiner: BinOpKind,
base: bool,
) -> BlockOrExpr {
let op = |cx: &mut ExtCtxt<'_>, span: Span, self_f: P<Expr>, other_fs: &[P<Expr>]| {
let [other_f] = other_fs else {
cx.span_bug(span, "not exactly 2 arguments in `derive(PartialEq)`");
};
cx.expr_binary(span, op, self_f, other_f.clone())
};
let expr = cs_fold(
true, // use foldl
|cx, span, subexpr, self_f, other_fs| {
let eq = op(cx, span, self_f, other_fs);
cx.expr_binary(span, combiner, subexpr, eq)
},
|cx, args| {
match args {
Some((span, self_f, other_fs)) => {
// Special-case the base case to generate cleaner code.
op(cx, span, self_f, other_fs)
}
None => cx.expr_bool(span, base),
}
},
Box::new(|cx, span, _| cx.expr_bool(span, !base)),
cx,
span,
substr,
|cx, fold| match fold {
CsFold::Single(field) => {
let [other_expr] = &field.other_selflike_exprs[..] else {
cx.span_bug(field.span, "not exactly 2 arguments in `derive(PartialEq)`");
};
cx.expr_binary(field.span, op, field.self_expr.clone(), other_expr.clone())
}
CsFold::Combine(span, expr1, expr2) => cx.expr_binary(span, combiner, expr1, expr2),
CsFold::Fieldless => cx.expr_bool(span, base),
CsFold::EnumNonMatching(span, _tag_tuple) => cx.expr_bool(span, !base),
},
);
BlockOrExpr::new_expr(expr)
}
@ -69,7 +57,7 @@ pub fn expand_deriving_partial_eq(
name: $name,
generics: Bounds::empty(),
explicit_self: true,
args: vec![(self_ref(), sym::other)],
nonself_args: vec![(self_ref(), sym::other)],
ret_ty: Path(path_local!(bool)),
attributes: attrs,
unify_fieldless_variants: true,

102
compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs
View File

@ -2,8 +2,7 @@ use crate::deriving::generic::ty::*;
use crate::deriving::generic::*;
use crate::deriving::{path_std, pathvec_std};
use rustc_ast::ptr::P;
use rustc_ast::{Expr, MetaItem};
use rustc_ast::MetaItem;
use rustc_expand::base::{Annotatable, ExtCtxt};
use rustc_span::symbol::{sym, Ident};
use rustc_span::Span;
@ -26,7 +25,7 @@ pub fn expand_deriving_partial_ord(
name: sym::partial_cmp,
generics: Bounds::empty(),
explicit_self: true,
args: vec![(self_ref(), sym::other)],
nonself_args: vec![(self_ref(), sym::other)],
ret_ty,
attributes: attrs,
unify_fieldless_variants: true,
@ -50,79 +49,54 @@ pub fn expand_deriving_partial_ord(
pub fn cs_partial_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> BlockOrExpr {
let test_id = Ident::new(sym::cmp, span);
let ordering = cx.path_global(span, cx.std_path(&[sym::cmp, sym::Ordering, sym::Equal]));
let ordering_expr = cx.expr_path(ordering.clone());
let equal_path = cx.path_global(span, cx.std_path(&[sym::cmp, sym::Ordering, sym::Equal]));
let partial_cmp_path = cx.std_path(&[sym::cmp, sym::PartialOrd, sym::partial_cmp]);
// Builds:
//
// match ::std::cmp::PartialOrd::partial_cmp(&self_field1, &other_field1) {
// ::std::option::Option::Some(::std::cmp::Ordering::Equal) =>
// match ::std::cmp::PartialOrd::partial_cmp(&self_field2, &other_field2) {
// ::std::option::Option::Some(::std::cmp::Ordering::Equal) => {
// ...
// match ::core::cmp::PartialOrd::partial_cmp(&self.x, &other.x) {
// ::core::option::Option::Some(::core::cmp::Ordering::Equal) =>
// ::core::cmp::PartialOrd::partial_cmp(&self.y, &other.y),
// cmp => cmp,
// }
// cmp => cmp
// },
// cmp => cmp
// }
//
let expr = cs_fold(
// foldr nests the if-elses correctly, leaving the first field
// as the outermost one, and the last as the innermost.
false,
|cx, span, old, self_f, other_fs| {
// match new {
// Some(::std::cmp::Ordering::Equal) => old,
// cmp => cmp
// }
let new = {
let [other_f] = other_fs else {
cx.span_bug(span, "not exactly 2 arguments in `derive(PartialOrd)`");
};
let args =
vec![cx.expr_addr_of(span, self_f), cx.expr_addr_of(span, other_f.clone())];
cx.expr_call_global(span, partial_cmp_path.clone(), args)
};
let eq_arm = cx.arm(span, cx.pat_some(span, cx.pat_path(span, ordering.clone())), old);
let neq_arm = cx.arm(span, cx.pat_ident(span, test_id), cx.expr_ident(span, test_id));
cx.expr_match(span, new, vec![eq_arm, neq_arm])
},
|cx: &mut ExtCtxt<'_>, args: Option<(Span, P<Expr>, &[P<Expr>])>| match args {
Some((span, self_f, other_fs)) => {
let new = {
let [other_f] = other_fs else {
cx.span_bug(span, "not exactly 2 arguments in `derive(Ord)`");
};
let args =
vec![cx.expr_addr_of(span, self_f), cx.expr_addr_of(span, other_f.clone())];
cx.expr_call_global(span, partial_cmp_path.clone(), args)
};
new
}
None => cx.expr_some(span, ordering_expr.clone()),
},
Box::new(|cx, span, tag_tuple| {
if tag_tuple.len() != 2 {
cx.span_bug(span, "not exactly 2 arguments in `derive(PartialOrd)`")
} else {
let lft = cx.expr_addr_of(span, cx.expr_ident(span, tag_tuple[0]));
let rgt = cx.expr_addr_of(span, cx.expr_ident(span, tag_tuple[1]));
let fn_partial_cmp_path =
cx.std_path(&[sym::cmp, sym::PartialOrd, sym::partial_cmp]);
cx.expr_call_global(span, fn_partial_cmp_path, vec![lft, rgt])
}
}),
cx,
span,
substr,
|cx, fold| match fold {
CsFold::Single(field) => {
let [other_expr] = &field.other_selflike_exprs[..] else {
cx.span_bug(field.span, "not exactly 2 arguments in `derive(Ord)`");
};
let args = vec![
cx.expr_addr_of(field.span, field.self_expr.clone()),
cx.expr_addr_of(field.span, other_expr.clone()),
];
cx.expr_call_global(field.span, partial_cmp_path.clone(), args)
}
CsFold::Combine(span, expr1, expr2) => {
let eq_arm =
cx.arm(span, cx.pat_some(span, cx.pat_path(span, equal_path.clone())), expr1);
let neq_arm =
cx.arm(span, cx.pat_ident(span, test_id), cx.expr_ident(span, test_id));
cx.expr_match(span, expr2, vec![eq_arm, neq_arm])
}
CsFold::Fieldless => cx.expr_some(span, cx.expr_path(equal_path.clone())),
CsFold::EnumNonMatching(span, tag_tuple) => {
if tag_tuple.len() != 2 {
cx.span_bug(span, "not exactly 2 arguments in `derive(PartialOrd)`")
} else {
let lft = cx.expr_addr_of(span, cx.expr_ident(span, tag_tuple[0]));
let rgt = cx.expr_addr_of(span, cx.expr_ident(span, tag_tuple[1]));
let fn_partial_cmp_path =
cx.std_path(&[sym::cmp, sym::PartialOrd, sym::partial_cmp]);
cx.expr_call_global(span, fn_partial_cmp_path, vec![lft, rgt])
}
}
},
);
BlockOrExpr::new_expr(expr)
}

8
compiler/rustc_builtin_macros/src/deriving/debug.rs
View File

@ -28,7 +28,7 @@ pub fn expand_deriving_debug(
name: sym::fmt,
generics: Bounds::empty(),
explicit_self: true,
args: vec![(fmtr, sym::f)],
nonself_args: vec![(fmtr, sym::f)],
ret_ty: Path(path_std!(fmt::Result)),
attributes: Vec::new(),
unify_fieldless_variants: false,
@ -53,7 +53,7 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
// We want to make sure we have the ctxt set so that we can use unstable methods
let span = cx.with_def_site_ctxt(span);
let name = cx.expr_lit(span, ast::LitKind::Str(ident.name, ast::StrStyle::Cooked));
let fmt = substr.nonself_args[0].clone();
let fmt = substr.nonselflike_args[0].clone();
// Struct and tuples are similar enough that we use the same code for both,
// with some extra pieces for structs due to the field names.
@ -96,7 +96,7 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
args.push(name);
}
// Use double indirection to make sure this works for unsized types
let field = cx.expr_addr_of(field.span, field.self_.clone());
let field = cx.expr_addr_of(field.span, field.self_expr.clone());
let field = cx.expr_addr_of(field.span, field);
args.push(field);
}
@ -116,7 +116,7 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
}
// Use double indirection to make sure this works for unsized types
let value_ref = cx.expr_addr_of(field.span, field.self_.clone());
let value_ref = cx.expr_addr_of(field.span, field.self_expr.clone());
value_exprs.push(cx.expr_addr_of(field.span, value_ref));
}

7
compiler/rustc_builtin_macros/src/deriving/decodable.rs
View File

@ -36,7 +36,10 @@ pub fn expand_deriving_rustc_decodable(
)],
},
explicit_self: false,
args: vec![(Ref(Box::new(Path(Path::new_local(typaram))), Mutability::Mut), sym::d)],
nonself_args: vec![(
Ref(Box::new(Path(Path::new_local(typaram))), Mutability::Mut),
sym::d,
)],
ret_ty: Path(Path::new_(
pathvec_std!(result::Result),
vec![
@ -63,7 +66,7 @@ fn decodable_substructure(
substr: &Substructure<'_>,
krate: Symbol,
) -> BlockOrExpr {
let decoder = substr.nonself_args[0].clone();
let decoder = substr.nonselflike_args[0].clone();
let recurse = vec![
Ident::new(krate, trait_span),
Ident::new(sym::Decodable, trait_span),

2
compiler/rustc_builtin_macros/src/deriving/default.rs
View File

@ -34,7 +34,7 @@ pub fn expand_deriving_default(
name: kw::Default,
generics: Bounds::empty(),
explicit_self: false,
args: Vec::new(),
nonself_args: Vec::new(),
ret_ty: Self_,
attributes: attrs,
unify_fieldless_variants: false,

15
compiler/rustc_builtin_macros/src/deriving/encodable.rs
View File

@ -120,7 +120,10 @@ pub fn expand_deriving_rustc_encodable(
)],
},
explicit_self: true,
args: vec![(Ref(Box::new(Path(Path::new_local(typaram))), Mutability::Mut), sym::s)],
nonself_args: vec![(
Ref(Box::new(Path(Path::new_local(typaram))), Mutability::Mut),
sym::s,
)],
ret_ty: Path(Path::new_(
pathvec_std!(result::Result),
vec![
@ -147,7 +150,7 @@ fn encodable_substructure(
substr: &Substructure<'_>,
krate: Symbol,
) -> BlockOrExpr {
let encoder = substr.nonself_args[0].clone();
let encoder = substr.nonselflike_args[0].clone();
// throw an underscore in front to suppress unused variable warnings
let blkarg = Ident::new(sym::_e, trait_span);
let blkencoder = cx.expr_ident(trait_span, blkarg);
@ -165,12 +168,12 @@ fn encodable_substructure(
let fn_emit_struct_field_path =
cx.def_site_path(&[sym::rustc_serialize, sym::Encoder, sym::emit_struct_field]);
let mut stmts = Vec::new();
for (i, &FieldInfo { name, ref self_, span, .. }) in fields.iter().enumerate() {
for (i, &FieldInfo { name, ref self_expr, span, .. }) in fields.iter().enumerate() {
let name = match name {
Some(id) => id.name,
None => Symbol::intern(&format!("_field{}", i)),
};
let self_ref = cx.expr_addr_of(span, self_.clone());
let self_ref = cx.expr_addr_of(span, self_expr.clone());
let enc = cx.expr_call(span, fn_path.clone(), vec![self_ref, blkencoder.clone()]);
let lambda = cx.lambda1(span, enc, blkarg);
let call = cx.expr_call_global(
@ -234,8 +237,8 @@ fn encodable_substructure(
let mut stmts = Vec::new();
if !fields.is_empty() {
let last = fields.len() - 1;
for (i, &FieldInfo { ref self_, span, .. }) in fields.iter().enumerate() {
let self_ref = cx.expr_addr_of(span, self_.clone());
for (i, &FieldInfo { ref self_expr, span, .. }) in fields.iter().enumerate() {
let self_ref = cx.expr_addr_of(span, self_expr.clone());
let enc =
cx.expr_call(span, fn_path.clone(), vec![self_ref, blkencoder.clone()]);
let lambda = cx.lambda1(span, enc, blkarg);

736
compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
View File

File diff suppressed because it is too large Load Diff

8
compiler/rustc_builtin_macros/src/deriving/hash.rs
View File

@ -30,7 +30,7 @@ pub fn expand_deriving_hash(
name: sym::hash,
generics: Bounds { bounds: vec![(typaram, vec![path_std!(hash::Hasher)])] },
explicit_self: true,
args: vec![(Ref(Box::new(Path(arg)), Mutability::Mut), sym::state)],
nonself_args: vec![(Ref(Box::new(Path(arg)), Mutability::Mut), sym::state)],
ret_ty: Unit,
attributes: vec![],
unify_fieldless_variants: true,
@ -49,7 +49,7 @@ fn hash_substructure(
trait_span: Span,
substr: &Substructure<'_>,
) -> BlockOrExpr {
let [state_expr] = substr.nonself_args else {
let [state_expr] = substr.nonselflike_args else {
cx.span_bug(trait_span, "incorrect number of arguments in `derive(Hash)`");
};
let call_hash = |span, thing_expr| {
@ -82,7 +82,9 @@ fn hash_substructure(
};
stmts.extend(
fields.iter().map(|FieldInfo { ref self_, span, .. }| call_hash(*span, self_.clone())),
fields
.iter()
.map(|FieldInfo { ref self_expr, span, .. }| call_hash(*span, self_expr.clone())),
);
BlockOrExpr::new_stmts(stmts)
}