Remove pretty-print/reparse hack, and add derive-specific hack
This commit is contained in:
parent
2987785df3
commit
530a629635
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@ -44,6 +44,12 @@ pub enum TokenTree {
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Delimited(DelimSpan, DelimToken, TokenStream),
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}
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#[derive(Copy, Clone)]
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pub enum CanSynthesizeMissingTokens {
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Yes,
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No,
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}
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// Ensure all fields of `TokenTree` is `Send` and `Sync`.
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#[cfg(parallel_compiler)]
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fn _dummy()
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@ -37,7 +37,7 @@
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use rustc_ast::node_id::NodeMap;
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use rustc_ast::token::{self, DelimToken, Nonterminal, Token};
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use rustc_ast::tokenstream::{DelimSpan, TokenStream, TokenTree};
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use rustc_ast::tokenstream::{CanSynthesizeMissingTokens, DelimSpan, TokenStream, TokenTree};
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use rustc_ast::visit::{self, AssocCtxt, Visitor};
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use rustc_ast::walk_list;
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use rustc_ast::{self as ast, *};
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@ -206,7 +206,8 @@ pub trait ResolverAstLowering {
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) -> LocalDefId;
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}
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type NtToTokenstream = fn(&Nonterminal, &ParseSess, Span) -> TokenStream;
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type NtToTokenstream =
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fn(&Nonterminal, &ParseSess, Span, CanSynthesizeMissingTokens) -> TokenStream;
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/// Context of `impl Trait` in code, which determines whether it is allowed in an HIR subtree,
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/// and if so, what meaning it has.
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@ -393,6 +394,47 @@ enum AnonymousLifetimeMode {
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PassThrough,
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}
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struct TokenStreamLowering<'a> {
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parse_sess: &'a ParseSess,
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synthesize_tokens: CanSynthesizeMissingTokens,
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nt_to_tokenstream: NtToTokenstream,
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}
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impl<'a> TokenStreamLowering<'a> {
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fn lower_token_stream(&mut self, tokens: TokenStream) -> TokenStream {
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tokens.into_trees().flat_map(|tree| self.lower_token_tree(tree).into_trees()).collect()
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}
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fn lower_token_tree(&mut self, tree: TokenTree) -> TokenStream {
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match tree {
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TokenTree::Token(token) => self.lower_token(token),
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TokenTree::Delimited(span, delim, tts) => {
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TokenTree::Delimited(span, delim, self.lower_token_stream(tts)).into()
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}
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}
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}
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fn lower_token(&mut self, token: Token) -> TokenStream {
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match token.kind {
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token::Interpolated(nt) => {
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let tts = (self.nt_to_tokenstream)(
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&nt,
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self.parse_sess,
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token.span,
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self.synthesize_tokens,
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);
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TokenTree::Delimited(
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DelimSpan::from_single(token.span),
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DelimToken::NoDelim,
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self.lower_token_stream(tts),
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)
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.into()
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}
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_ => TokenTree::Token(token).into(),
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}
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}
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}
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struct ImplTraitTypeIdVisitor<'a> {
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ids: &'a mut SmallVec<[NodeId; 1]>,
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}
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@ -955,42 +997,51 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
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match *args {
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MacArgs::Empty => MacArgs::Empty,
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MacArgs::Delimited(dspan, delim, ref tokens) => {
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MacArgs::Delimited(dspan, delim, self.lower_token_stream(tokens.clone()))
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}
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MacArgs::Eq(eq_span, ref tokens) => {
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MacArgs::Eq(eq_span, self.lower_token_stream(tokens.clone()))
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}
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}
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}
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fn lower_token_stream(&mut self, tokens: TokenStream) -> TokenStream {
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tokens.into_trees().flat_map(|tree| self.lower_token_tree(tree).into_trees()).collect()
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}
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fn lower_token_tree(&mut self, tree: TokenTree) -> TokenStream {
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match tree {
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TokenTree::Token(token) => self.lower_token(token),
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TokenTree::Delimited(span, delim, tts) => {
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TokenTree::Delimited(span, delim, self.lower_token_stream(tts)).into()
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}
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}
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}
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fn lower_token(&mut self, token: Token) -> TokenStream {
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match token.kind {
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token::Interpolated(nt) => {
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let tts = (self.nt_to_tokenstream)(&nt, &self.sess.parse_sess, token.span);
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TokenTree::Delimited(
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DelimSpan::from_single(token.span),
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DelimToken::NoDelim,
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self.lower_token_stream(tts),
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// This is either a non-key-value attribute, or a `macro_rules!` body.
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// We either not have any nonterminals present (in the case of an attribute),
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// or have tokens available for all nonterminals in the case of a nested
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// `macro_rules`: e.g:
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//
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// ```rust
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// macro_rules! outer {
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// ($e:expr) => {
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// macro_rules! inner {
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// () => { $e }
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// }
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// }
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// }
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// ```
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//
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// In both cases, we don't want to synthesize any tokens
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MacArgs::Delimited(
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dspan,
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delim,
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self.lower_token_stream(tokens.clone(), CanSynthesizeMissingTokens::No),
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)
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.into()
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}
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_ => TokenTree::Token(token).into(),
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// This is an inert key-value attribute - it will never be visible to macros
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// after it gets lowered to HIR. Therefore, we can synthesize tokens with fake
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// spans to handle nonterminals in `#[doc]` (e.g. `#[doc = $e]`).
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MacArgs::Eq(eq_span, ref tokens) => MacArgs::Eq(
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eq_span,
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self.lower_token_stream(tokens.clone(), CanSynthesizeMissingTokens::Yes),
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),
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}
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}
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fn lower_token_stream(
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&self,
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tokens: TokenStream,
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synthesize_tokens: CanSynthesizeMissingTokens,
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) -> TokenStream {
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TokenStreamLowering {
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parse_sess: &self.sess.parse_sess,
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synthesize_tokens,
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nt_to_tokenstream: self.nt_to_tokenstream,
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}
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.lower_token_stream(tokens)
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}
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/// Given an associated type constraint like one of these:
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///
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/// ```
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@ -2,8 +2,8 @@ use crate::expand::{self, AstFragment, Invocation};
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use crate::module::DirectoryOwnership;
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use rustc_ast::ptr::P;
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use rustc_ast::token;
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use rustc_ast::tokenstream::TokenStream;
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use rustc_ast::token::{self, Nonterminal};
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use rustc_ast::tokenstream::{CanSynthesizeMissingTokens, TokenStream};
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use rustc_ast::visit::{AssocCtxt, Visitor};
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use rustc_ast::{self as ast, Attribute, NodeId, PatKind};
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use rustc_attr::{self as attr, Deprecation, HasAttrs, Stability};
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@ -119,8 +119,8 @@ impl Annotatable {
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}
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}
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crate fn into_tokens(self, sess: &ParseSess) -> TokenStream {
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let nt = match self {
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crate fn into_nonterminal(self) -> Nonterminal {
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match self {
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Annotatable::Item(item) => token::NtItem(item),
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Annotatable::TraitItem(item) | Annotatable::ImplItem(item) => {
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token::NtItem(P(item.and_then(ast::AssocItem::into_item)))
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@ -137,8 +137,11 @@ impl Annotatable {
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| Annotatable::Param(..)
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| Annotatable::StructField(..)
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| Annotatable::Variant(..) => panic!("unexpected annotatable"),
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};
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nt_to_tokenstream(&nt, sess, DUMMY_SP)
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}
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}
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crate fn into_tokens(self, sess: &ParseSess) -> TokenStream {
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nt_to_tokenstream(&self.into_nonterminal(), sess, DUMMY_SP, CanSynthesizeMissingTokens::No)
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}
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pub fn expect_item(self) -> P<ast::Item> {
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@ -29,6 +29,7 @@ use smallvec::SmallVec;
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pub struct StripUnconfigured<'a> {
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pub sess: &'a Session,
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pub features: Option<&'a Features>,
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pub modified: bool,
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}
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fn get_features(
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@ -199,7 +200,7 @@ fn get_features(
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// `cfg_attr`-process the crate's attributes and compute the crate's features.
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pub fn features(sess: &Session, mut krate: ast::Crate) -> (ast::Crate, Features) {
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let mut strip_unconfigured = StripUnconfigured { sess, features: None };
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let mut strip_unconfigured = StripUnconfigured { sess, features: None, modified: false };
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let unconfigured_attrs = krate.attrs.clone();
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let diag = &sess.parse_sess.span_diagnostic;
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@ -243,7 +244,12 @@ const CFG_ATTR_NOTE_REF: &str = "for more information, visit \
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impl<'a> StripUnconfigured<'a> {
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pub fn configure<T: HasAttrs>(&mut self, mut node: T) -> Option<T> {
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self.process_cfg_attrs(&mut node);
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self.in_cfg(node.attrs()).then_some(node)
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if self.in_cfg(node.attrs()) {
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Some(node)
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} else {
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self.modified = true;
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None
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}
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}
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/// Parse and expand all `cfg_attr` attributes into a list of attributes
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@ -270,6 +276,9 @@ impl<'a> StripUnconfigured<'a> {
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return vec![attr];
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}
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// A `#[cfg_attr]` either gets removed, or replaced with a new attribute
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self.modified = true;
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let (cfg_predicate, expanded_attrs) = match self.parse_cfg_attr(&attr) {
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None => return vec![],
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Some(r) => r,
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@ -12,7 +12,7 @@ use rustc_ast::ptr::P;
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use rustc_ast::token;
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use rustc_ast::tokenstream::TokenStream;
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use rustc_ast::visit::{self, AssocCtxt, Visitor};
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use rustc_ast::{self as ast, AttrItem, Block, LitKind, NodeId, PatKind, Path};
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use rustc_ast::{self as ast, AttrItem, AttrStyle, Block, LitKind, NodeId, PatKind, Path};
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use rustc_ast::{ItemKind, MacArgs, MacCallStmt, MacStmtStyle, StmtKind, Unsafe};
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use rustc_ast_pretty::pprust;
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use rustc_attr::{self as attr, is_builtin_attr, HasAttrs};
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@ -522,12 +522,29 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
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item.visit_attrs(|attrs| attrs.retain(|a| !a.has_name(sym::derive)));
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(item, Vec::new())
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} else {
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let mut item = StripUnconfigured {
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let mut visitor = StripUnconfigured {
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sess: self.cx.sess,
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features: self.cx.ecfg.features,
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}
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.fully_configure(item);
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modified: false,
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};
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let mut item = visitor.fully_configure(item);
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item.visit_attrs(|attrs| attrs.retain(|a| !a.has_name(sym::derive)));
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if visitor.modified && !derives.is_empty() {
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// Erase the tokens if cfg-stripping modified the item
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// This will cause us to synthesize fake tokens
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// when `nt_to_tokenstream` is called on this item.
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match &mut item {
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Annotatable::Item(item) => item.tokens = None,
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Annotatable::Stmt(stmt) => {
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if let StmtKind::Item(item) = &mut stmt.kind {
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item.tokens = None
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} else {
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panic!("Unexpected stmt {:?}", stmt);
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}
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}
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_ => panic!("Unexpected annotatable {:?}", item),
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}
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}
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invocations.reserve(derives.len());
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let derive_placeholders = derives
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@ -622,7 +639,11 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
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let invocations = {
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let mut collector = InvocationCollector {
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cfg: StripUnconfigured { sess: &self.cx.sess, features: self.cx.ecfg.features },
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cfg: StripUnconfigured {
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sess: &self.cx.sess,
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features: self.cx.ecfg.features,
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modified: false,
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},
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cx: self.cx,
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invocations: Vec::new(),
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monotonic: self.monotonic,
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@ -716,7 +737,15 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
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SyntaxExtensionKind::Attr(expander) => {
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self.gate_proc_macro_input(&item);
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self.gate_proc_macro_attr_item(span, &item);
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let tokens = item.into_tokens(&self.cx.sess.parse_sess);
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let tokens = match attr.style {
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AttrStyle::Outer => item.into_tokens(&self.cx.sess.parse_sess),
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// FIXME: Properly collect tokens for inner attributes
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AttrStyle::Inner => rustc_parse::fake_token_stream(
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&self.cx.sess.parse_sess,
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&item.into_nonterminal(),
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span,
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),
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};
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let attr_item = attr.unwrap_normal_item();
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if let MacArgs::Eq(..) = attr_item.args {
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self.cx.span_err(span, "key-value macro attributes are not supported");
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@ -3,7 +3,7 @@ use crate::proc_macro_server;
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use rustc_ast::ptr::P;
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use rustc_ast::token;
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use rustc_ast::tokenstream::{TokenStream, TokenTree};
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use rustc_ast::tokenstream::{CanSynthesizeMissingTokens, TokenStream, TokenTree};
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use rustc_ast::{self as ast, *};
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use rustc_data_structures::sync::Lrc;
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use rustc_errors::{struct_span_err, Applicability, ErrorReported};
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@ -94,7 +94,12 @@ impl MultiItemModifier for ProcMacroDerive {
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let input = if item.pretty_printing_compatibility_hack() {
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TokenTree::token(token::Interpolated(Lrc::new(item)), DUMMY_SP).into()
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} else {
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nt_to_tokenstream(&item, &ecx.sess.parse_sess, DUMMY_SP)
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nt_to_tokenstream(
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&item,
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&ecx.sess.parse_sess,
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DUMMY_SP,
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CanSynthesizeMissingTokens::Yes,
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)
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};
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let server = proc_macro_server::Rustc::new(ecx);
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@ -2,7 +2,8 @@ use crate::base::ExtCtxt;
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use rustc_ast as ast;
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use rustc_ast::token;
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use rustc_ast::tokenstream::{self, DelimSpan, Spacing::*, TokenStream, TreeAndSpacing};
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use rustc_ast::tokenstream::{self, CanSynthesizeMissingTokens};
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use rustc_ast::tokenstream::{DelimSpan, Spacing::*, TokenStream, TreeAndSpacing};
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use rustc_ast_pretty::pprust;
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use rustc_data_structures::sync::Lrc;
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use rustc_errors::Diagnostic;
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@ -178,7 +179,7 @@ impl FromInternal<(TreeAndSpacing, &'_ ParseSess, &'_ mut Vec<Self>)>
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{
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TokenTree::Ident(Ident::new(sess, name.name, is_raw, name.span))
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} else {
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let stream = nt_to_tokenstream(&nt, sess, span);
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let stream = nt_to_tokenstream(&nt, sess, span, CanSynthesizeMissingTokens::No);
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TokenTree::Group(Group {
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delimiter: Delimiter::None,
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stream,
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@ -7,22 +7,18 @@
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use rustc_ast as ast;
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use rustc_ast::attr::HasAttrs;
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use rustc_ast::token::{self, DelimToken, Nonterminal, Token, TokenKind};
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use rustc_ast::tokenstream::{self, LazyTokenStream, TokenStream, TokenTree};
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use rustc_ast::token::{self, Nonterminal};
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use rustc_ast::tokenstream::{self, CanSynthesizeMissingTokens, LazyTokenStream, TokenStream};
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use rustc_ast_pretty::pprust;
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use rustc_data_structures::fx::FxHashSet;
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use rustc_data_structures::sync::Lrc;
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use rustc_errors::{Diagnostic, FatalError, Level, PResult};
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use rustc_session::parse::ParseSess;
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use rustc_span::{symbol::kw, FileName, SourceFile, Span, DUMMY_SP};
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use rustc_span::{FileName, SourceFile, Span};
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use smallvec::SmallVec;
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use std::cell::RefCell;
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use std::mem;
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use std::path::Path;
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use std::str;
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use tracing::{debug, info};
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use tracing::debug;
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pub const MACRO_ARGUMENTS: Option<&str> = Some("macro arguments");
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|
@ -237,7 +233,12 @@ pub fn parse_in<'a, T>(
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// NOTE(Centril): The following probably shouldn't be here but it acknowledges the
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// fact that architecturally, we are using parsing (read on below to understand why).
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pub fn nt_to_tokenstream(nt: &Nonterminal, sess: &ParseSess, span: Span) -> TokenStream {
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pub fn nt_to_tokenstream(
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nt: &Nonterminal,
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sess: &ParseSess,
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span: Span,
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synthesize_tokens: CanSynthesizeMissingTokens,
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) -> TokenStream {
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// A `Nonterminal` is often a parsed AST item. At this point we now
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// need to convert the parsed AST to an actual token stream, e.g.
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// un-parse it basically.
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|
@ -255,9 +256,11 @@ pub fn nt_to_tokenstream(nt: &Nonterminal, sess: &ParseSess, span: Span) -> Toke
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|tokens: Option<&LazyTokenStream>| tokens.as_ref().map(|t| t.create_token_stream());
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let tokens = match *nt {
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Nonterminal::NtItem(ref item) => prepend_attrs(&item.attrs, item.tokens.as_ref()),
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Nonterminal::NtItem(ref item) => {
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prepend_attrs(sess, &item.attrs, nt, span, item.tokens.as_ref())
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}
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Nonterminal::NtBlock(ref block) => convert_tokens(block.tokens.as_ref()),
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Nonterminal::NtStmt(ref stmt) => prepend_attrs(stmt.attrs(), stmt.tokens()),
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Nonterminal::NtStmt(ref stmt) => prepend_attrs(sess, stmt.attrs(), nt, span, stmt.tokens()),
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Nonterminal::NtPat(ref pat) => convert_tokens(pat.tokens.as_ref()),
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Nonterminal::NtTy(ref ty) => convert_tokens(ty.tokens.as_ref()),
|
||||
Nonterminal::NtIdent(ident, is_raw) => {
|
||||
|
@ -274,376 +277,45 @@ pub fn nt_to_tokenstream(nt: &Nonterminal, sess: &ParseSess, span: Span) -> Toke
|
|||
if expr.tokens.is_none() {
|
||||
debug!("missing tokens for expr {:?}", expr);
|
||||
}
|
||||
prepend_attrs(&expr.attrs, expr.tokens.as_ref())
|
||||
prepend_attrs(sess, &expr.attrs, nt, span, expr.tokens.as_ref())
|
||||
}
|
||||
};
|
||||
|
||||
// Caches the stringification of 'good' `TokenStreams` which passed
|
||||
// `tokenstream_probably_equal_for_proc_macro`. This allows us to avoid
|
||||
// repeatedly stringifying and comparing the same `TokenStream` for deeply
|
||||
// nested nonterminals.
|
||||
//
|
||||
// We cache by the strinification instead of the `TokenStream` to avoid
|
||||
// needing to implement `Hash` for `TokenStream`. Note that it's possible to
|
||||
// have two distinct `TokenStream`s that stringify to the same result
|
||||
// (e.g. if they differ only in hygiene information). However, any
|
||||
// information lost during the stringification process is also intentionally
|
||||
// ignored by `tokenstream_probably_equal_for_proc_macro`, so it's fine
|
||||
// that a single cache entry may 'map' to multiple distinct `TokenStream`s.
|
||||
//
|
||||
// This is a temporary hack to prevent compilation blowup on certain inputs.
|
||||
// The entire pretty-print/retokenize process will be removed soon.
|
||||
thread_local! {
|
||||
static GOOD_TOKEN_CACHE: RefCell<FxHashSet<String>> = Default::default();
|
||||
}
|
||||
|
||||
// FIXME(#43081): Avoid this pretty-print + reparse hack
|
||||
// Pretty-print the AST struct without inserting any parenthesis
|
||||
// beyond those explicitly written by the user (e.g. `ExpnKind::Paren`).
|
||||
// The resulting stream may have incorrect precedence, but it's only
|
||||
// ever used for a comparison against the capture tokenstream.
|
||||
let source = pprust::nonterminal_to_string_no_extra_parens(nt);
|
||||
let filename = FileName::macro_expansion_source_code(&source);
|
||||
let reparsed_tokens = parse_stream_from_source_str(filename, source.clone(), sess, Some(span));
|
||||
|
||||
// During early phases of the compiler the AST could get modified
|
||||
// directly (e.g., attributes added or removed) and the internal cache
|
||||
// of tokens my not be invalidated or updated. Consequently if the
|
||||
// "lossless" token stream disagrees with our actual stringification
|
||||
// (which has historically been much more battle-tested) then we go
|
||||
// with the lossy stream anyway (losing span information).
|
||||
//
|
||||
// Note that the comparison isn't `==` here to avoid comparing spans,
|
||||
// but it *also* is a "probable" equality which is a pretty weird
|
||||
// definition. We mostly want to catch actual changes to the AST
|
||||
// like a `#[cfg]` being processed or some weird `macro_rules!`
|
||||
// expansion.
|
||||
//
|
||||
// What we *don't* want to catch is the fact that a user-defined
|
||||
// literal like `0xf` is stringified as `15`, causing the cached token
|
||||
// stream to not be literal `==` token-wise (ignoring spans) to the
|
||||
// token stream we got from stringification.
|
||||
//
|
||||
// Instead the "probably equal" check here is "does each token
|
||||
// recursively have the same discriminant?" We basically don't look at
|
||||
// the token values here and assume that such fine grained token stream
|
||||
// modifications, including adding/removing typically non-semantic
|
||||
// tokens such as extra braces and commas, don't happen.
|
||||
if let Some(tokens) = tokens {
|
||||
if GOOD_TOKEN_CACHE.with(|cache| cache.borrow().contains(&source)) {
|
||||
return tokens;
|
||||
}
|
||||
|
||||
// Compare with a non-relaxed delim match to start.
|
||||
if tokenstream_probably_equal_for_proc_macro(&tokens, &reparsed_tokens, sess, false) {
|
||||
GOOD_TOKEN_CACHE.with(|cache| cache.borrow_mut().insert(source.clone()));
|
||||
return tokens;
|
||||
}
|
||||
|
||||
// The check failed. This time, we pretty-print the AST struct with parenthesis
|
||||
// inserted to preserve precedence. This may cause `None`-delimiters in the captured
|
||||
// token stream to match up with inserted parenthesis in the reparsed stream.
|
||||
let source_with_parens = pprust::nonterminal_to_string(nt);
|
||||
let filename_with_parens = FileName::macro_expansion_source_code(&source_with_parens);
|
||||
|
||||
if GOOD_TOKEN_CACHE.with(|cache| cache.borrow().contains(&source_with_parens)) {
|
||||
return tokens;
|
||||
}
|
||||
|
||||
let reparsed_tokens_with_parens = parse_stream_from_source_str(
|
||||
filename_with_parens,
|
||||
source_with_parens,
|
||||
sess,
|
||||
Some(span),
|
||||
);
|
||||
|
||||
// Compare with a relaxed delim match - we want inserted parenthesis in the
|
||||
// reparsed stream to match `None`-delimiters in the original stream.
|
||||
if tokenstream_probably_equal_for_proc_macro(
|
||||
&tokens,
|
||||
&reparsed_tokens_with_parens,
|
||||
sess,
|
||||
true,
|
||||
) {
|
||||
GOOD_TOKEN_CACHE.with(|cache| cache.borrow_mut().insert(source.clone()));
|
||||
return tokens;
|
||||
}
|
||||
|
||||
info!(
|
||||
"cached tokens found, but they're not \"probably equal\", \
|
||||
going with stringified version"
|
||||
);
|
||||
info!("cached tokens: {}", pprust::tts_to_string(&tokens));
|
||||
info!("reparsed tokens: {}", pprust::tts_to_string(&reparsed_tokens_with_parens));
|
||||
|
||||
info!("cached tokens debug: {:?}", tokens);
|
||||
info!("reparsed tokens debug: {:?}", reparsed_tokens_with_parens);
|
||||
}
|
||||
reparsed_tokens
|
||||
}
|
||||
|
||||
// See comments in `Nonterminal::to_tokenstream` for why we care about
|
||||
// *probably* equal here rather than actual equality
|
||||
//
|
||||
// This is otherwise the same as `eq_unspanned`, only recursing with a
|
||||
// different method.
|
||||
pub fn tokenstream_probably_equal_for_proc_macro(
|
||||
tokens: &TokenStream,
|
||||
reparsed_tokens: &TokenStream,
|
||||
sess: &ParseSess,
|
||||
relaxed_delim_match: bool,
|
||||
) -> bool {
|
||||
// When checking for `probably_eq`, we ignore certain tokens that aren't
|
||||
// preserved in the AST. Because they are not preserved, the pretty
|
||||
// printer arbitrarily adds or removes them when printing as token
|
||||
// streams, making a comparison between a token stream generated from an
|
||||
// AST and a token stream which was parsed into an AST more reliable.
|
||||
fn semantic_tree(tree: &TokenTree) -> bool {
|
||||
if let TokenTree::Token(token) = tree {
|
||||
if let
|
||||
// The pretty printer tends to add trailing commas to
|
||||
// everything, and in particular, after struct fields.
|
||||
| token::Comma
|
||||
// The pretty printer collapses many semicolons into one.
|
||||
| token::Semi
|
||||
// We don't preserve leading `|` tokens in patterns, so
|
||||
// we ignore them entirely
|
||||
| token::BinOp(token::BinOpToken::Or)
|
||||
// We don't preserve trailing '+' tokens in trait bounds,
|
||||
// so we ignore them entirely
|
||||
| token::BinOp(token::BinOpToken::Plus)
|
||||
// The pretty printer can turn `$crate` into `::crate_name`
|
||||
| token::ModSep = token.kind {
|
||||
return false;
|
||||
}
|
||||
}
|
||||
true
|
||||
}
|
||||
|
||||
// When comparing two `TokenStream`s, we ignore the `IsJoint` information.
|
||||
//
|
||||
// However, `rustc_parse::lexer::tokentrees::TokenStreamBuilder` will
|
||||
// use `Token.glue` on adjacent tokens with the proper `IsJoint`.
|
||||
// Since we are ignoreing `IsJoint`, a 'glued' token (e.g. `BinOp(Shr)`)
|
||||
// and its 'split'/'unglued' compoenents (e.g. `Gt, Gt`) are equivalent
|
||||
// when determining if two `TokenStream`s are 'probably equal'.
|
||||
//
|
||||
// Therefore, we use `break_two_token_op` to convert all tokens
|
||||
// to the 'unglued' form (if it exists). This ensures that two
|
||||
// `TokenStream`s which differ only in how their tokens are glued
|
||||
// will be considered 'probably equal', which allows us to keep spans.
|
||||
//
|
||||
// This is important when the original `TokenStream` contained
|
||||
// extra spaces (e.g. `f :: < Vec < _ > > ( ) ;'). These extra spaces
|
||||
// will be omitted when we pretty-print, which can cause the original
|
||||
// and reparsed `TokenStream`s to differ in the assignment of `IsJoint`,
|
||||
// leading to some tokens being 'glued' together in one stream but not
|
||||
// the other. See #68489 for more details.
|
||||
fn break_tokens(tree: TokenTree) -> impl Iterator<Item = TokenTree> {
|
||||
// In almost all cases, we should have either zero or one levels
|
||||
// of 'unglueing'. However, in some unusual cases, we may need
|
||||
// to iterate breaking tokens mutliple times. For example:
|
||||
// '[BinOpEq(Shr)] => [Gt, Ge] -> [Gt, Gt, Eq]'
|
||||
let mut token_trees: SmallVec<[_; 2]>;
|
||||
if let TokenTree::Token(token) = tree {
|
||||
let mut out = SmallVec::<[_; 2]>::new();
|
||||
out.push(token);
|
||||
// Iterate to fixpoint:
|
||||
// * We start off with 'out' containing our initial token, and `temp` empty
|
||||
// * If we are able to break any tokens in `out`, then `out` will have
|
||||
// at least one more element than 'temp', so we will try to break tokens
|
||||
// again.
|
||||
// * If we cannot break any tokens in 'out', we are done
|
||||
loop {
|
||||
let mut temp = SmallVec::<[_; 2]>::new();
|
||||
let mut changed = false;
|
||||
|
||||
for token in out.into_iter() {
|
||||
if let Some((first, second)) = token.kind.break_two_token_op() {
|
||||
temp.push(Token::new(first, DUMMY_SP));
|
||||
temp.push(Token::new(second, DUMMY_SP));
|
||||
changed = true;
|
||||
} else {
|
||||
temp.push(token);
|
||||
}
|
||||
}
|
||||
out = temp;
|
||||
if !changed {
|
||||
break;
|
||||
}
|
||||
}
|
||||
token_trees = out.into_iter().map(TokenTree::Token).collect();
|
||||
} else {
|
||||
token_trees = SmallVec::new();
|
||||
token_trees.push(tree);
|
||||
}
|
||||
token_trees.into_iter()
|
||||
}
|
||||
|
||||
fn expand_token(tree: TokenTree, sess: &ParseSess) -> impl Iterator<Item = TokenTree> {
|
||||
// When checking tokenstreams for 'probable equality', we are comparing
|
||||
// a captured (from parsing) `TokenStream` to a reparsed tokenstream.
|
||||
// The reparsed Tokenstream will never have `None`-delimited groups,
|
||||
// since they are only ever inserted as a result of macro expansion.
|
||||
// Therefore, inserting a `None`-delimtied group here (when we
|
||||
// convert a nested `Nonterminal` to a tokenstream) would cause
|
||||
// a mismatch with the reparsed tokenstream.
|
||||
//
|
||||
// Note that we currently do not handle the case where the
|
||||
// reparsed stream has a `Parenthesis`-delimited group
|
||||
// inserted. This will cause a spurious mismatch:
|
||||
// issue #75734 tracks resolving this.
|
||||
|
||||
let expanded: SmallVec<[_; 1]> =
|
||||
if let TokenTree::Token(Token { kind: TokenKind::Interpolated(nt), span }) = &tree {
|
||||
nt_to_tokenstream(nt, sess, *span)
|
||||
.into_trees()
|
||||
.flat_map(|t| expand_token(t, sess))
|
||||
.collect()
|
||||
} else {
|
||||
// Filter before and after breaking tokens,
|
||||
// since we may want to ignore both glued and unglued tokens.
|
||||
std::iter::once(tree)
|
||||
.filter(semantic_tree)
|
||||
.flat_map(break_tokens)
|
||||
.filter(semantic_tree)
|
||||
.collect()
|
||||
};
|
||||
expanded.into_iter()
|
||||
}
|
||||
|
||||
// Break tokens after we expand any nonterminals, so that we break tokens
|
||||
// that are produced as a result of nonterminal expansion.
|
||||
let tokens = tokens.trees().flat_map(|t| expand_token(t, sess));
|
||||
let reparsed_tokens = reparsed_tokens.trees().flat_map(|t| expand_token(t, sess));
|
||||
|
||||
tokens.eq_by(reparsed_tokens, |t, rt| {
|
||||
tokentree_probably_equal_for_proc_macro(&t, &rt, sess, relaxed_delim_match)
|
||||
})
|
||||
}
|
||||
|
||||
// See comments in `Nonterminal::to_tokenstream` for why we care about
|
||||
// *probably* equal here rather than actual equality
|
||||
//
|
||||
// This is otherwise the same as `eq_unspanned`, only recursing with a
|
||||
// different method.
|
||||
pub fn tokentree_probably_equal_for_proc_macro(
|
||||
token: &TokenTree,
|
||||
reparsed_token: &TokenTree,
|
||||
sess: &ParseSess,
|
||||
relaxed_delim_match: bool,
|
||||
) -> bool {
|
||||
match (token, reparsed_token) {
|
||||
(TokenTree::Token(token), TokenTree::Token(reparsed_token)) => {
|
||||
token_probably_equal_for_proc_macro(token, reparsed_token)
|
||||
}
|
||||
(
|
||||
TokenTree::Delimited(_, delim, tokens),
|
||||
TokenTree::Delimited(_, reparsed_delim, reparsed_tokens),
|
||||
) if delim == reparsed_delim => tokenstream_probably_equal_for_proc_macro(
|
||||
tokens,
|
||||
reparsed_tokens,
|
||||
sess,
|
||||
relaxed_delim_match,
|
||||
),
|
||||
(TokenTree::Delimited(_, DelimToken::NoDelim, tokens), reparsed_token) => {
|
||||
if relaxed_delim_match {
|
||||
if let TokenTree::Delimited(_, DelimToken::Paren, reparsed_tokens) = reparsed_token
|
||||
{
|
||||
if tokenstream_probably_equal_for_proc_macro(
|
||||
tokens,
|
||||
reparsed_tokens,
|
||||
sess,
|
||||
relaxed_delim_match,
|
||||
) {
|
||||
return true;
|
||||
}
|
||||
}
|
||||
}
|
||||
tokens.len() == 1
|
||||
&& tokentree_probably_equal_for_proc_macro(
|
||||
&tokens.trees().next().unwrap(),
|
||||
reparsed_token,
|
||||
sess,
|
||||
relaxed_delim_match,
|
||||
)
|
||||
}
|
||||
_ => false,
|
||||
return tokens;
|
||||
} else if matches!(synthesize_tokens, CanSynthesizeMissingTokens::Yes) {
|
||||
return fake_token_stream(sess, nt, span);
|
||||
} else {
|
||||
let pretty = rustc_ast_pretty::pprust::nonterminal_to_string_no_extra_parens(&nt);
|
||||
panic!("Missing tokens at {:?} for nt {:?}", span, pretty);
|
||||
}
|
||||
}
|
||||
|
||||
// See comments in `Nonterminal::to_tokenstream` for why we care about
|
||||
// *probably* equal here rather than actual equality
|
||||
fn token_probably_equal_for_proc_macro(first: &Token, other: &Token) -> bool {
|
||||
if mem::discriminant(&first.kind) != mem::discriminant(&other.kind) {
|
||||
return false;
|
||||
}
|
||||
use rustc_ast::token::TokenKind::*;
|
||||
match (&first.kind, &other.kind) {
|
||||
(&Eq, &Eq)
|
||||
| (&Lt, &Lt)
|
||||
| (&Le, &Le)
|
||||
| (&EqEq, &EqEq)
|
||||
| (&Ne, &Ne)
|
||||
| (&Ge, &Ge)
|
||||
| (&Gt, &Gt)
|
||||
| (&AndAnd, &AndAnd)
|
||||
| (&OrOr, &OrOr)
|
||||
| (&Not, &Not)
|
||||
| (&Tilde, &Tilde)
|
||||
| (&At, &At)
|
||||
| (&Dot, &Dot)
|
||||
| (&DotDot, &DotDot)
|
||||
| (&DotDotDot, &DotDotDot)
|
||||
| (&DotDotEq, &DotDotEq)
|
||||
| (&Comma, &Comma)
|
||||
| (&Semi, &Semi)
|
||||
| (&Colon, &Colon)
|
||||
| (&ModSep, &ModSep)
|
||||
| (&RArrow, &RArrow)
|
||||
| (&LArrow, &LArrow)
|
||||
| (&FatArrow, &FatArrow)
|
||||
| (&Pound, &Pound)
|
||||
| (&Dollar, &Dollar)
|
||||
| (&Question, &Question)
|
||||
| (&Eof, &Eof) => true,
|
||||
|
||||
(&BinOp(a), &BinOp(b)) | (&BinOpEq(a), &BinOpEq(b)) => a == b,
|
||||
|
||||
(&OpenDelim(a), &OpenDelim(b)) | (&CloseDelim(a), &CloseDelim(b)) => a == b,
|
||||
|
||||
(&DocComment(a1, a2, a3), &DocComment(b1, b2, b3)) => a1 == b1 && a2 == b2 && a3 == b3,
|
||||
|
||||
(&Literal(a), &Literal(b)) => a == b,
|
||||
|
||||
(&Lifetime(a), &Lifetime(b)) => a == b,
|
||||
(&Ident(a, b), &Ident(c, d)) => {
|
||||
b == d && (a == c || a == kw::DollarCrate || c == kw::DollarCrate)
|
||||
}
|
||||
|
||||
(&Interpolated(..), &Interpolated(..)) => panic!("Unexpanded Interpolated!"),
|
||||
|
||||
_ => panic!("forgot to add a token?"),
|
||||
}
|
||||
pub fn fake_token_stream(sess: &ParseSess, nt: &Nonterminal, span: Span) -> TokenStream {
|
||||
let source = pprust::nonterminal_to_string(nt);
|
||||
let filename = FileName::macro_expansion_source_code(&source);
|
||||
parse_stream_from_source_str(filename, source, sess, Some(span))
|
||||
}
|
||||
|
||||
fn prepend_attrs(
|
||||
sess: &ParseSess,
|
||||
attrs: &[ast::Attribute],
|
||||
nt: &Nonterminal,
|
||||
span: Span,
|
||||
tokens: Option<&tokenstream::LazyTokenStream>,
|
||||
) -> Option<tokenstream::TokenStream> {
|
||||
let tokens = tokens?.create_token_stream();
|
||||
if attrs.is_empty() {
|
||||
return Some(tokens);
|
||||
return Some(tokens?.create_token_stream());
|
||||
}
|
||||
let mut builder = tokenstream::TokenStreamBuilder::new();
|
||||
for attr in attrs {
|
||||
// FIXME: Correctly handle tokens for inner attributes.
|
||||
// For now, we fall back to reparsing the original AST node
|
||||
if attr.style == ast::AttrStyle::Inner {
|
||||
return None;
|
||||
return Some(fake_token_stream(sess, nt, span));
|
||||
}
|
||||
builder.push(attr.tokens());
|
||||
}
|
||||
builder.push(tokens);
|
||||
builder.push(tokens?.create_token_stream());
|
||||
Some(builder.build())
|
||||
}
|
||||
|
|
Loading…
Reference in New Issue