diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_data_structures/src/tagged_ptr/impl_tag.rs | 144 | ||||
| -rw-r--r-- | compiler/rustc_expand/src/expand.rs | 126 | ||||
| -rw-r--r-- | compiler/rustc_expand/src/mbe/metavar_expr.rs | 32 | ||||
| -rw-r--r-- | compiler/rustc_expand/src/mbe/transcribe.rs | 65 |
4 files changed, 335 insertions, 32 deletions
diff --git a/compiler/rustc_data_structures/src/tagged_ptr/impl_tag.rs b/compiler/rustc_data_structures/src/tagged_ptr/impl_tag.rs index cb7f7d318dc..cafa91c8b8b 100644 --- a/compiler/rustc_data_structures/src/tagged_ptr/impl_tag.rs +++ b/compiler/rustc_data_structures/src/tagged_ptr/impl_tag.rs @@ -81,6 +81,7 @@ /// E::A, /// } /// ``` +#[cfg(bootstrap)] #[macro_export] macro_rules! impl_tag { ( @@ -140,5 +141,148 @@ macro_rules! impl_tag { }; } +/// Implements [`Tag`] for a given type. +/// +/// You can use `impl_tag` on structs and enums. +/// You need to specify the type and all its possible values, +/// which can only be paths with optional fields. +/// +/// [`Tag`]: crate::tagged_ptr::Tag +/// +/// # Examples +/// +/// Basic usage: +/// +/// ``` +/// #![feature(macro_metavar_expr)] +/// use rustc_data_structures::{impl_tag, tagged_ptr::Tag}; +/// +/// #[derive(Copy, Clone, PartialEq, Debug)] +/// enum SomeTag { +/// A, +/// B, +/// X { v: bool }, +/// Y(bool, bool), +/// } +/// +/// impl_tag! { +/// // The type for which the `Tag` will be implemented +/// impl Tag for SomeTag; +/// // You need to specify all possible tag values: +/// SomeTag::A, // 0 +/// SomeTag::B, // 1 +/// // For variants with fields, you need to specify the fields: +/// SomeTag::X { v: true }, // 2 +/// SomeTag::X { v: false }, // 3 +/// // For tuple variants use named syntax: +/// SomeTag::Y { 0: true, 1: true }, // 4 +/// SomeTag::Y { 0: false, 1: true }, // 5 +/// SomeTag::Y { 0: true, 1: false }, // 6 +/// SomeTag::Y { 0: false, 1: false }, // 7 +/// } +/// +/// // Tag values are assigned in order: +/// assert_eq!(SomeTag::A.into_usize(), 0); +/// assert_eq!(SomeTag::X { v: false }.into_usize(), 3); +/// assert_eq!(SomeTag::Y(false, true).into_usize(), 5); +/// +/// assert_eq!(unsafe { SomeTag::from_usize(1) }, SomeTag::B); +/// assert_eq!(unsafe { SomeTag::from_usize(2) }, SomeTag::X { v: true }); +/// assert_eq!(unsafe { SomeTag::from_usize(7) }, SomeTag::Y(false, false)); +/// ``` +/// +/// Structs are supported: +/// +/// ``` +/// #![feature(macro_metavar_expr)] +/// # use rustc_data_structures::impl_tag; +/// #[derive(Copy, Clone)] +/// struct Flags { a: bool, b: bool } +/// +/// impl_tag! { +/// impl Tag for Flags; +/// Flags { a: true, b: true }, +/// Flags { a: false, b: true }, +/// Flags { a: true, b: false }, +/// Flags { a: false, b: false }, +/// } +/// ``` +/// +/// Not specifying all values results in a compile error: +/// +/// ```compile_fail,E0004 +/// #![feature(macro_metavar_expr)] +/// # use rustc_data_structures::impl_tag; +/// #[derive(Copy, Clone)] +/// enum E { +/// A, +/// B, +/// } +/// +/// impl_tag! { +/// impl Tag for E; +/// E::A, +/// } +/// ``` +#[cfg(not(bootstrap))] +#[macro_export] +macro_rules! impl_tag { + ( + impl Tag for $Self:ty; + $( + $($path:ident)::* $( { $( $fields:tt )* })?, + )* + ) => { + // Safety: + // `bits_for_tags` is called on the same `${index()}`-es as + // `into_usize` returns, thus `BITS` constant is correct. + unsafe impl $crate::tagged_ptr::Tag for $Self { + const BITS: u32 = $crate::tagged_ptr::bits_for_tags(&[ + $( + ${index()}, + $( ${ignore($path)} )* + )* + ]); + + #[inline] + fn into_usize(self) -> usize { + // This forbids use of repeating patterns (`Enum::V`&`Enum::V`, etc) + // (or at least it should, see <https://github.com/rust-lang/rust/issues/110613>) + #[forbid(unreachable_patterns)] + match self { + // `match` is doing heavy lifting here, by requiring exhaustiveness + $( + $($path)::* $( { $( $fields )* } )? => ${index()}, + )* + } + } + + #[inline] + unsafe fn from_usize(tag: usize) -> Self { + match tag { + $( + ${index()} => $($path)::* $( { $( $fields )* } )?, + )* + + // Safety: + // `into_usize` only returns `${index()}` of the same + // repetition as we are filtering above, thus if this is + // reached, the safety contract of this function was + // already breached. + _ => unsafe { + debug_assert!( + false, + "invalid tag: {tag}\ + (this is a bug in the caller of `from_usize`)" + ); + std::hint::unreachable_unchecked() + }, + } + } + + } + }; +} + #[cfg(test)] mod tests; diff --git a/compiler/rustc_expand/src/expand.rs b/compiler/rustc_expand/src/expand.rs index 47d4b802c0f..89caf8aa231 100644 --- a/compiler/rustc_expand/src/expand.rs +++ b/compiler/rustc_expand/src/expand.rs @@ -41,6 +41,7 @@ use std::path::PathBuf; use std::rc::Rc; use std::{iter, mem}; +#[cfg(bootstrap)] macro_rules! ast_fragments { ( $($Kind:ident($AstTy:ty) { @@ -165,6 +166,131 @@ macro_rules! ast_fragments { } } +#[cfg(not(bootstrap))] +macro_rules! ast_fragments { + ( + $($Kind:ident($AstTy:ty) { + $kind_name:expr; + $(one fn $mut_visit_ast:ident; fn $visit_ast:ident;)? + $(many fn $flat_map_ast_elt:ident; fn $visit_ast_elt:ident($($args:tt)*);)? + fn $make_ast:ident; + })* + ) => { + /// A fragment of AST that can be produced by a single macro expansion. + /// Can also serve as an input and intermediate result for macro expansion operations. + pub enum AstFragment { + OptExpr(Option<P<ast::Expr>>), + MethodReceiverExpr(P<ast::Expr>), + $($Kind($AstTy),)* + } + + /// "Discriminant" of an AST fragment. + #[derive(Copy, Clone, PartialEq, Eq)] + pub enum AstFragmentKind { + OptExpr, + MethodReceiverExpr, + $($Kind,)* + } + + impl AstFragmentKind { + pub fn name(self) -> &'static str { + match self { + AstFragmentKind::OptExpr => "expression", + AstFragmentKind::MethodReceiverExpr => "expression", + $(AstFragmentKind::$Kind => $kind_name,)* + } + } + + fn make_from<'a>(self, result: Box<dyn MacResult + 'a>) -> Option<AstFragment> { + match self { + AstFragmentKind::OptExpr => + result.make_expr().map(Some).map(AstFragment::OptExpr), + AstFragmentKind::MethodReceiverExpr => + result.make_expr().map(AstFragment::MethodReceiverExpr), + $(AstFragmentKind::$Kind => result.$make_ast().map(AstFragment::$Kind),)* + } + } + } + + impl AstFragment { + pub fn add_placeholders(&mut self, placeholders: &[NodeId]) { + if placeholders.is_empty() { + return; + } + match self { + $($(AstFragment::$Kind(ast) => ast.extend(placeholders.iter().flat_map(|id| { + ${ignore($flat_map_ast_elt)} + placeholder(AstFragmentKind::$Kind, *id, None).$make_ast() + })),)?)* + _ => panic!("unexpected AST fragment kind") + } + } + + pub fn make_opt_expr(self) -> Option<P<ast::Expr>> { + match self { + AstFragment::OptExpr(expr) => expr, + _ => panic!("AstFragment::make_* called on the wrong kind of fragment"), + } + } + + pub fn make_method_receiver_expr(self) -> P<ast::Expr> { + match self { + AstFragment::MethodReceiverExpr(expr) => expr, + _ => panic!("AstFragment::make_* called on the wrong kind of fragment"), + } + } + + $(pub fn $make_ast(self) -> $AstTy { + match self { + AstFragment::$Kind(ast) => ast, + _ => panic!("AstFragment::make_* called on the wrong kind of fragment"), + } + })* + + fn make_ast<T: InvocationCollectorNode>(self) -> T::OutputTy { + T::fragment_to_output(self) + } + + pub fn mut_visit_with<F: MutVisitor>(&mut self, vis: &mut F) { + match self { + AstFragment::OptExpr(opt_expr) => { + visit_clobber(opt_expr, |opt_expr| { + if let Some(expr) = opt_expr { + vis.filter_map_expr(expr) + } else { + None + } + }); + } + AstFragment::MethodReceiverExpr(expr) => vis.visit_method_receiver_expr(expr), + $($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)?)* + $($(AstFragment::$Kind(ast) => + ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast)),)?)* + } + } + + pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) { + match self { + AstFragment::OptExpr(Some(expr)) => visitor.visit_expr(expr), + AstFragment::OptExpr(None) => {} + AstFragment::MethodReceiverExpr(expr) => visitor.visit_method_receiver_expr(expr), + $($(AstFragment::$Kind(ast) => visitor.$visit_ast(ast),)?)* + $($(AstFragment::$Kind(ast) => for ast_elt in &ast[..] { + visitor.$visit_ast_elt(ast_elt, $($args)*); + })?)* + } + } + } + + impl<'a> MacResult for crate::mbe::macro_rules::ParserAnyMacro<'a> { + $(fn $make_ast(self: Box<crate::mbe::macro_rules::ParserAnyMacro<'a>>) + -> Option<$AstTy> { + Some(self.make(AstFragmentKind::$Kind).$make_ast()) + })* + } + } +} + ast_fragments! { Expr(P<ast::Expr>) { "expression"; one fn visit_expr; fn visit_expr; fn make_expr; } Pat(P<ast::Pat>) { "pattern"; one fn visit_pat; fn visit_pat; fn make_pat; } diff --git a/compiler/rustc_expand/src/mbe/metavar_expr.rs b/compiler/rustc_expand/src/mbe/metavar_expr.rs index c29edc3dc9f..4b8c6feb93e 100644 --- a/compiler/rustc_expand/src/mbe/metavar_expr.rs +++ b/compiler/rustc_expand/src/mbe/metavar_expr.rs @@ -10,9 +10,8 @@ use rustc_span::Span; /// A meta-variable expression, for expansions based on properties of meta-variables. #[derive(Debug, Clone, PartialEq, Encodable, Decodable)] pub(crate) enum MetaVarExpr { - /// The number of repetitions of an identifier, optionally limited to a number - /// of outer-most repetition depths. If the depth limit is `None` then the depth is unlimited. - Count(Ident, Option<usize>), + /// The number of repetitions of an identifier. + Count(Ident, usize), /// Ignore a meta-variable for repetition without expansion. Ignore(Ident), @@ -43,7 +42,10 @@ impl MetaVarExpr { let mut iter = args.trees(); let rslt = match ident.as_str() { "count" => parse_count(&mut iter, sess, ident.span)?, - "ignore" => MetaVarExpr::Ignore(parse_ident(&mut iter, sess, ident.span)?), + "ignore" => { + eat_dollar(&mut iter, sess, ident.span)?; + MetaVarExpr::Ignore(parse_ident(&mut iter, sess, ident.span)?) + } "index" => MetaVarExpr::Index(parse_depth(&mut iter, sess, ident.span)?), "length" => MetaVarExpr::Length(parse_depth(&mut iter, sess, ident.span)?), _ => { @@ -92,6 +94,7 @@ fn parse_count<'sess>( sess: &'sess ParseSess, span: Span, ) -> PResult<'sess, MetaVarExpr> { + eat_dollar(iter, sess, span)?; let ident = parse_ident(iter, sess, span)?; let depth = if try_eat_comma(iter) { if iter.look_ahead(0).is_none() { @@ -100,9 +103,9 @@ fn parse_count<'sess>( "`count` followed by a comma must have an associated index indicating its depth", )); } - Some(parse_depth(iter, sess, span)?) + parse_depth(iter, sess, span)? } else { - None + 0 }; Ok(MetaVarExpr::Count(ident, depth)) } @@ -166,3 +169,20 @@ fn try_eat_comma(iter: &mut RefTokenTreeCursor<'_>) -> bool { } false } + +/// Expects that the next item is a dollar sign. +fn eat_dollar<'sess>( + iter: &mut RefTokenTreeCursor<'_>, + sess: &'sess ParseSess, + span: Span, +) -> PResult<'sess, ()> { + if let Some(TokenTree::Token(token::Token { kind: token::Dollar, .. }, _)) = iter.look_ahead(0) + { + let _ = iter.next(); + return Ok(()); + } + Err(sess.span_diagnostic.struct_span_err( + span, + "meta-variables within meta-variable expressions must be referenced using a dollar sign", + )) +} diff --git a/compiler/rustc_expand/src/mbe/transcribe.rs b/compiler/rustc_expand/src/mbe/transcribe.rs index 18707cebcd5..80fd82e0302 100644 --- a/compiler/rustc_expand/src/mbe/transcribe.rs +++ b/compiler/rustc_expand/src/mbe/transcribe.rs @@ -440,7 +440,7 @@ fn lockstep_iter_size( /// declared inside a single repetition and the index `1` implies two nested repetitions. fn count_repetitions<'a>( cx: &ExtCtxt<'a>, - depth_opt: Option<usize>, + depth_user: usize, mut matched: &NamedMatch, repeats: &[(usize, usize)], sp: &DelimSpan, @@ -449,37 +449,45 @@ fn count_repetitions<'a>( // (or at the top-level of `matched` if no depth is given). fn count<'a>( cx: &ExtCtxt<'a>, - declared_lhs_depth: usize, - depth_opt: Option<usize>, + depth_curr: usize, + depth_max: usize, matched: &NamedMatch, sp: &DelimSpan, ) -> PResult<'a, usize> { match matched { - MatchedTokenTree(_) | MatchedNonterminal(_) => { - if declared_lhs_depth == 0 { - return Err(cx.create_err(CountRepetitionMisplaced { span: sp.entire() })); - } - match depth_opt { - None => Ok(1), - Some(_) => Err(out_of_bounds_err(cx, declared_lhs_depth, sp.entire(), "count")), - } - } + MatchedTokenTree(_) | MatchedNonterminal(_) => Ok(1), MatchedSeq(named_matches) => { - let new_declared_lhs_depth = declared_lhs_depth + 1; - match depth_opt { - None => named_matches - .iter() - .map(|elem| count(cx, new_declared_lhs_depth, None, elem, sp)) - .sum(), - Some(0) => Ok(named_matches.len()), - Some(depth) => named_matches + if depth_curr == depth_max { + Ok(named_matches.len()) + } else { + named_matches .iter() - .map(|elem| count(cx, new_declared_lhs_depth, Some(depth - 1), elem, sp)) - .sum(), + .map(|elem| count(cx, depth_curr + 1, depth_max, elem, sp)) + .sum() } } } } + + /// Maximum depth + fn depth(counter: usize, matched: &NamedMatch) -> usize { + match matched { + MatchedTokenTree(_) | MatchedNonterminal(_) => counter, + MatchedSeq(named_matches) => { + let rslt = counter + 1; + if let Some(elem) = named_matches.first() { depth(rslt, elem) } else { rslt } + } + } + } + + let depth_max = depth(0, matched) + .checked_sub(1) + .and_then(|el| el.checked_sub(repeats.len())) + .unwrap_or_default(); + if depth_user > depth_max { + return Err(out_of_bounds_err(cx, depth_max + 1, sp.entire(), "count")); + } + // `repeats` records all of the nested levels at which we are currently // matching meta-variables. The meta-var-expr `count($x)` only counts // matches that occur in this "subtree" of the `NamedMatch` where we @@ -491,7 +499,12 @@ fn count_repetitions<'a>( matched = &ads[idx]; } } - count(cx, 0, depth_opt, matched, sp) + + if let MatchedTokenTree(_) | MatchedNonterminal(_) = matched { + return Err(cx.create_err(CountRepetitionMisplaced { span: sp.entire() })); + } + + count(cx, depth_user, depth_max, matched, sp) } /// Returns a `NamedMatch` item declared on the LHS given an arbitrary [Ident] @@ -523,7 +536,7 @@ fn out_of_bounds_err<'a>( ) } else { format!( - "depth parameter on meta-variable expression `{ty}` \ + "depth parameter of meta-variable expression `{ty}` \ must be less than {max}" ) }; @@ -545,9 +558,9 @@ fn transcribe_metavar_expr<'a>( span }; match *expr { - MetaVarExpr::Count(original_ident, depth_opt) => { + MetaVarExpr::Count(original_ident, depth) => { let matched = matched_from_ident(cx, original_ident, interp)?; - let count = count_repetitions(cx, depth_opt, matched, repeats, sp)?; + let count = count_repetitions(cx, depth, matched, repeats, sp)?; let tt = TokenTree::token_alone( TokenKind::lit(token::Integer, sym::integer(count), None), visited_span(), |