Auto merge of #78782 - petrochenkov:nodoctok, r=Aaron1011

Do not collect tokens for doc comments Doc comment is a single token and AST has all the information to re-create it precisely. Doc comments are also responsible for majority of calls to `collect_tokens` (with `num_calls == 1` and `num_calls == 0`, cc #78736). (I also moved token collection into `fn parse_attribute` to deduplicate code a bit.) r? `@Aaron1011`
rust-lang · Nov 12, 2020 · 5a6a41e · 5a6a41e
2 parents 77180db + 12de1e8
commit 5a6a41e
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Showing 17 changed files with 140 additions and 161 deletions.
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
@@ -2439,13 +2439,12 @@ pub struct Attribute {
     /// or the construct this attribute is contained within (inner).
     pub style: AttrStyle,
     pub span: Span,
-    pub tokens: Option<LazyTokenStream>,
 }
 
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub enum AttrKind {
     /// A normal attribute.
-    Normal(AttrItem),
+    Normal(AttrItem, Option<LazyTokenStream>),
 
     /// A doc comment (e.g. `/// ...`, `//! ...`, `/** ... */`, `/*! ... */`).
     /// Doc attributes (e.g. `#[doc="..."]`) are represented with the `Normal`

diff --git a/compiler/rustc_ast/src/attr/mod.rs b/compiler/rustc_ast/src/attr/mod.rs
@@ -8,7 +8,7 @@ use crate::ast::{Path, PathSegment};
 use crate::mut_visit::visit_clobber;
 use crate::ptr::P;
 use crate::token::{self, CommentKind, Token};
-use crate::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndSpacing};
+use crate::tokenstream::{DelimSpan, LazyTokenStream, TokenStream, TokenTree, TreeAndSpacing};
 
 use rustc_index::bit_set::GrowableBitSet;
 use rustc_span::source_map::{BytePos, Spanned};
@@ -120,15 +120,15 @@ impl NestedMetaItem {
 impl Attribute {
     pub fn has_name(&self, name: Symbol) -> bool {
         match self.kind {
-            AttrKind::Normal(ref item) => item.path == name,
+            AttrKind::Normal(ref item, _) => item.path == name,
             AttrKind::DocComment(..) => false,
         }
     }
 
     /// For a single-segment attribute, returns its name; otherwise, returns `None`.
     pub fn ident(&self) -> Option<Ident> {
         match self.kind {
-            AttrKind::Normal(ref item) => {
+            AttrKind::Normal(ref item, _) => {
                 if item.path.segments.len() == 1 {
                     Some(item.path.segments[0].ident)
                 } else {
@@ -144,14 +144,14 @@ impl Attribute {
 
     pub fn value_str(&self) -> Option<Symbol> {
         match self.kind {
-            AttrKind::Normal(ref item) => item.meta(self.span).and_then(|meta| meta.value_str()),
+            AttrKind::Normal(ref item, _) => item.meta(self.span).and_then(|meta| meta.value_str()),
             AttrKind::DocComment(..) => None,
         }
     }
 
     pub fn meta_item_list(&self) -> Option<Vec<NestedMetaItem>> {
         match self.kind {
-            AttrKind::Normal(ref item) => match item.meta(self.span) {
+            AttrKind::Normal(ref item, _) => match item.meta(self.span) {
                 Some(MetaItem { kind: MetaItemKind::List(list), .. }) => Some(list),
                 _ => None,
             },
@@ -160,7 +160,7 @@ impl Attribute {
     }
 
     pub fn is_word(&self) -> bool {
-        if let AttrKind::Normal(item) = &self.kind {
+        if let AttrKind::Normal(item, _) = &self.kind {
             matches!(item.args, MacArgs::Empty)
         } else {
             false
@@ -246,15 +246,15 @@ impl AttrItem {
 impl Attribute {
     pub fn is_doc_comment(&self) -> bool {
         match self.kind {
-            AttrKind::Normal(_) => false,
+            AttrKind::Normal(..) => false,
             AttrKind::DocComment(..) => true,
         }
     }
 
     pub fn doc_str(&self) -> Option<Symbol> {
         match self.kind {
             AttrKind::DocComment(.., data) => Some(data),
-            AttrKind::Normal(ref item) if item.path == sym::doc => {
+            AttrKind::Normal(ref item, _) if item.path == sym::doc => {
                 item.meta(self.span).and_then(|meta| meta.value_str())
             }
             _ => None,
@@ -263,25 +263,37 @@ impl Attribute {
 
     pub fn get_normal_item(&self) -> &AttrItem {
         match self.kind {
-            AttrKind::Normal(ref item) => item,
+            AttrKind::Normal(ref item, _) => item,
             AttrKind::DocComment(..) => panic!("unexpected doc comment"),
         }
     }
 
     pub fn unwrap_normal_item(self) -> AttrItem {
         match self.kind {
-            AttrKind::Normal(item) => item,
+            AttrKind::Normal(item, _) => item,
             AttrKind::DocComment(..) => panic!("unexpected doc comment"),
         }
     }
 
     /// Extracts the MetaItem from inside this Attribute.
     pub fn meta(&self) -> Option<MetaItem> {
         match self.kind {
-            AttrKind::Normal(ref item) => item.meta(self.span),
+            AttrKind::Normal(ref item, _) => item.meta(self.span),
             AttrKind::DocComment(..) => None,
         }
     }
+
+    pub fn tokens(&self) -> TokenStream {
+        match self.kind {
+            AttrKind::Normal(_, ref tokens) => tokens
+                .as_ref()
+                .unwrap_or_else(|| panic!("attribute is missing tokens: {:?}", self))
+                .create_token_stream(),
+            AttrKind::DocComment(comment_kind, data) => TokenStream::from(TokenTree::Token(
+                Token::new(token::DocComment(comment_kind, self.style, data), self.span),
+            )),
+        }
+    }
 }
 
 /* Constructors */
@@ -321,11 +333,16 @@ crate fn mk_attr_id() -> AttrId {
 }
 
 pub fn mk_attr(style: AttrStyle, path: Path, args: MacArgs, span: Span) -> Attribute {
-    mk_attr_from_item(style, AttrItem { path, args, tokens: None }, span)
+    mk_attr_from_item(AttrItem { path, args, tokens: None }, None, style, span)
 }
 
-pub fn mk_attr_from_item(style: AttrStyle, item: AttrItem, span: Span) -> Attribute {
-    Attribute { kind: AttrKind::Normal(item), id: mk_attr_id(), style, span, tokens: None }
+pub fn mk_attr_from_item(
+    item: AttrItem,
+    tokens: Option<LazyTokenStream>,
+    style: AttrStyle,
+    span: Span,
+) -> Attribute {
+    Attribute { kind: AttrKind::Normal(item, tokens), id: mk_attr_id(), style, span }
 }
 
 /// Returns an inner attribute with the given value and span.
@@ -344,13 +361,7 @@ pub fn mk_doc_comment(
     data: Symbol,
     span: Span,
 ) -> Attribute {
-    Attribute {
-        kind: AttrKind::DocComment(comment_kind, data),
-        id: mk_attr_id(),
-        style,
-        span,
-        tokens: None,
-    }
+    Attribute { kind: AttrKind::DocComment(comment_kind, data), id: mk_attr_id(), style, span }
 }
 
 pub fn list_contains_name(items: &[NestedMetaItem], name: Symbol) -> bool {

diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
@@ -586,17 +586,17 @@ pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
 }
 
 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
-    let Attribute { kind, id: _, style: _, span, tokens } = attr;
+    let Attribute { kind, id: _, style: _, span } = attr;
     match kind {
-        AttrKind::Normal(AttrItem { path, args, tokens }) => {
+        AttrKind::Normal(AttrItem { path, args, tokens }, attr_tokens) => {
             vis.visit_path(path);
             visit_mac_args(args, vis);
             visit_lazy_tts(tokens, vis);
+            visit_lazy_tts(attr_tokens, vis);
         }
         AttrKind::DocComment(..) => {}
     }
     vis.visit_span(span);
-    visit_lazy_tts(tokens, vis);
 }
 
 pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {

diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
@@ -881,7 +881,7 @@ pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
 
 pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
     match attr.kind {
-        AttrKind::Normal(ref item) => walk_mac_args(visitor, &item.args),
+        AttrKind::Normal(ref item, ref _tokens) => walk_mac_args(visitor, &item.args),
         AttrKind::DocComment(..) => {}
     }
 }

diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
@@ -966,17 +966,20 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // Note that we explicitly do not walk the path. Since we don't really
         // lower attributes (we use the AST version) there is nowhere to keep
         // the `HirId`s. We don't actually need HIR version of attributes anyway.
+        // Tokens are also not needed after macro expansion and parsing.
         let kind = match attr.kind {
-            AttrKind::Normal(ref item) => AttrKind::Normal(AttrItem {
-                path: item.path.clone(),
-                args: self.lower_mac_args(&item.args),
-                tokens: None,
-            }),
+            AttrKind::Normal(ref item, _) => AttrKind::Normal(
+                AttrItem {
+                    path: item.path.clone(),
+                    args: self.lower_mac_args(&item.args),
+                    tokens: None,
+                },
+                None,
+            ),
             AttrKind::DocComment(comment_kind, data) => AttrKind::DocComment(comment_kind, data),
         };
 
-        // Tokens aren't needed after macro expansion and parsing
-        Attribute { kind, id: attr.id, style: attr.style, span: attr.span, tokens: None }
+        Attribute { kind, id: attr.id, style: attr.style, span: attr.span }
     }
 
     fn lower_mac_args(&mut self, args: &MacArgs) -> MacArgs {

diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -426,7 +426,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
         }
         self.maybe_print_comment(attr.span.lo());
         match attr.kind {
-            ast::AttrKind::Normal(ref item) => {
+            ast::AttrKind::Normal(ref item, _) => {
                 match attr.style {
                     ast::AttrStyle::Inner => self.word("#!["),
                     ast::AttrStyle::Outer => self.word("#["),

diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs
@@ -291,8 +291,7 @@ impl<'a> StripUnconfigured<'a> {
         expanded_attrs
             .into_iter()
             .flat_map(|(item, span)| {
-                let orig_tokens =
-                    attr.tokens.as_ref().unwrap_or_else(|| panic!("Missing tokens for {:?}", attr));
+                let orig_tokens = attr.tokens();
 
                 // We are taking an attribute of the form `#[cfg_attr(pred, attr)]`
                 // and producing an attribute of the form `#[attr]`. We
@@ -302,7 +301,7 @@ impl<'a> StripUnconfigured<'a> {
 
                 // Use the `#` in `#[cfg_attr(pred, attr)]` as the `#` token
                 // for `attr` when we expand it to `#[attr]`
-                let pound_token = orig_tokens.create_token_stream().trees().next().unwrap();
+                let pound_token = orig_tokens.trees().next().unwrap();
                 if !matches!(pound_token, TokenTree::Token(Token { kind: TokenKind::Pound, .. })) {
                     panic!("Bad tokens for attribute {:?}", attr);
                 }
@@ -316,13 +315,12 @@ impl<'a> StripUnconfigured<'a> {
                         .unwrap_or_else(|| panic!("Missing tokens for {:?}", item))
                         .create_token_stream(),
                 );
-
-                let mut attr = attr::mk_attr_from_item(attr.style, item, span);
-                attr.tokens = Some(LazyTokenStream::new(TokenStream::new(vec![
+                let tokens = Some(LazyTokenStream::new(TokenStream::new(vec![
                     (pound_token, Spacing::Alone),
                     (bracket_group, Spacing::Alone),
                 ])));
-                self.process_cfg_attr(attr)
+
+                self.process_cfg_attr(attr::mk_attr_from_item(item, tokens, attr.style, span))
             })
             .collect()
     }

diff --git a/compiler/rustc_expand/src/expand.rs b/compiler/rustc_expand/src/expand.rs
@@ -1776,15 +1776,13 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
 
             let meta = attr::mk_list_item(Ident::with_dummy_span(sym::doc), items);
             *at = ast::Attribute {
-                kind: ast::AttrKind::Normal(AttrItem {
-                    path: meta.path,
-                    args: meta.kind.mac_args(meta.span),
-                    tokens: None,
-                }),
+                kind: ast::AttrKind::Normal(
+                    AttrItem { path: meta.path, args: meta.kind.mac_args(meta.span), tokens: None },
+                    None,
+                ),
                 span: at.span,
                 id: at.id,
                 style: at.style,
-                tokens: None,
             };
         } else {
             noop_visit_attribute(at, self)

diff --git a/compiler/rustc_middle/src/ich/impls_syntax.rs b/compiler/rustc_middle/src/ich/impls_syntax.rs
@@ -40,8 +40,8 @@ impl<'ctx> rustc_ast::HashStableContext for StableHashingContext<'ctx> {
         debug_assert!(!attr.ident().map_or(false, |ident| self.is_ignored_attr(ident.name)));
         debug_assert!(!attr.is_doc_comment());
 
-        let ast::Attribute { kind, id: _, style, span, tokens } = attr;
-        if let ast::AttrKind::Normal(item) = kind {
+        let ast::Attribute { kind, id: _, style, span } = attr;
+        if let ast::AttrKind::Normal(item, tokens) = kind {
             item.hash_stable(self, hasher);
             style.hash_stable(self, hasher);
             span.hash_stable(self, hasher);

diff --git a/compiler/rustc_parse/src/lib.rs b/compiler/rustc_parse/src/lib.rs
@@ -616,12 +616,7 @@ fn prepend_attrs(
         if attr.style == ast::AttrStyle::Inner {
             return None;
         }
-        builder.push(
-            attr.tokens
-                .as_ref()
-                .unwrap_or_else(|| panic!("Attribute {:?} is missing tokens!", attr))
-                .create_token_stream(),
-        );
+        builder.push(attr.tokens());
     }
     builder.push(tokens);
     Some(builder.build())