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Avoid some token tree cloning in decl macro parsing.

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By changing `into_trees` into `trees`. Some of the subsequent paths
require explicit clones, but not all.
This commit is contained in:
Nicholas Nethercote 2023-07-27 11:04:26 +10:00
parent 853f453d57
commit d2f7f67921
2 changed files with 23 additions and 23 deletions
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4
compiler/rustc_expand/src/mbe/macro_rules.rs
View File

@ -500,7 +500,7 @@ pub fn compile_declarative_macro(
.map(|m| { .map(|m| {
if let MatchedTokenTree(tt) = m { if let MatchedTokenTree(tt) = m {
let tt = mbe::quoted::parse( let tt = mbe::quoted::parse(
TokenStream::new(vec![tt.clone()]), &TokenStream::new(vec![tt.clone()]),
true, true,
&sess.parse_sess, &sess.parse_sess,
def.id, def.id,
@ -524,7 +524,7 @@ pub fn compile_declarative_macro(
.map(|m| { .map(|m| {
if let MatchedTokenTree(tt) = m { if let MatchedTokenTree(tt) = m {
return mbe::quoted::parse( return mbe::quoted::parse(
TokenStream::new(vec![tt.clone()]), &TokenStream::new(vec![tt.clone()]),
false, false,
&sess.parse_sess, &sess.parse_sess,
def.id, def.id,

42
compiler/rustc_expand/src/mbe/quoted.rs
View File

@ -36,7 +36,7 @@ const VALID_FRAGMENT_NAMES_MSG: &str = "valid fragment specifiers are \
/// ///
/// A collection of `self::TokenTree`. There may also be some errors emitted to `sess`. /// A collection of `self::TokenTree`. There may also be some errors emitted to `sess`.
pub(super) fn parse( pub(super) fn parse(
input: tokenstream::TokenStream, input: &tokenstream::TokenStream,
parsing_patterns: bool, parsing_patterns: bool,
sess: &ParseSess, sess: &ParseSess,
node_id: NodeId, node_id: NodeId,
@ -48,7 +48,7 @@ pub(super) fn parse(
// For each token tree in `input`, parse the token into a `self::TokenTree`, consuming // For each token tree in `input`, parse the token into a `self::TokenTree`, consuming
// additional trees if need be. // additional trees if need be.
let mut trees = input.into_trees(); let mut trees = input.trees();
while let Some(tree) = trees.next() { while let Some(tree) = trees.next() {
// Given the parsed tree, if there is a metavar and we are expecting matchers, actually // Given the parsed tree, if there is a metavar and we are expecting matchers, actually
// parse out the matcher (i.e., in `$id:ident` this would parse the `:` and `ident`). // parse out the matcher (i.e., in `$id:ident` this would parse the `:` and `ident`).
@ -56,7 +56,7 @@ pub(super) fn parse(
match tree { match tree {
TokenTree::MetaVar(start_sp, ident) if parsing_patterns => { TokenTree::MetaVar(start_sp, ident) if parsing_patterns => {
let span = match trees.next() { let span = match trees.next() {
Some(tokenstream::TokenTree::Token(Token { kind: token::Colon, span }, _)) => { Some(&tokenstream::TokenTree::Token(Token { kind: token::Colon, span }, _)) => {
match trees.next() { match trees.next() {
Some(tokenstream::TokenTree::Token(token, _)) => match token.ident() { Some(tokenstream::TokenTree::Token(token, _)) => match token.ident() {
Some((frag, _)) => { Some((frag, _)) => {
@ -96,10 +96,10 @@ pub(super) fn parse(
} }
_ => token.span, _ => token.span,
}, },
tree => tree.as_ref().map_or(span, tokenstream::TokenTree::span), tree => tree.map_or(span, tokenstream::TokenTree::span),
} }
} }
tree => tree.as_ref().map_or(start_sp, tokenstream::TokenTree::span), tree => tree.map_or(start_sp, tokenstream::TokenTree::span),
}; };
result.push(TokenTree::MetaVarDecl(span, ident, None)); result.push(TokenTree::MetaVarDecl(span, ident, None));
@ -134,9 +134,9 @@ fn maybe_emit_macro_metavar_expr_feature(features: &Features, sess: &ParseSess,
/// - `parsing_patterns`: same as [parse]. /// - `parsing_patterns`: same as [parse].
/// - `sess`: the parsing session. Any errors will be emitted to this session. /// - `sess`: the parsing session. Any errors will be emitted to this session.
/// - `features`: language features so we can do feature gating. /// - `features`: language features so we can do feature gating.
fn parse_tree( fn parse_tree<'a>(
tree: tokenstream::TokenTree, tree: &'a tokenstream::TokenTree,
outer_trees: &mut impl Iterator<Item = tokenstream::TokenTree>, outer_trees: &mut impl Iterator<Item = &'a tokenstream::TokenTree>,
parsing_patterns: bool, parsing_patterns: bool,
sess: &ParseSess, sess: &ParseSess,
node_id: NodeId, node_id: NodeId,
@ -146,13 +146,13 @@ fn parse_tree(
// Depending on what `tree` is, we could be parsing different parts of a macro // Depending on what `tree` is, we could be parsing different parts of a macro
match tree { match tree {
// `tree` is a `$` token. Look at the next token in `trees` // `tree` is a `$` token. Look at the next token in `trees`
tokenstream::TokenTree::Token(Token { kind: token::Dollar, span }, _) => { &tokenstream::TokenTree::Token(Token { kind: token::Dollar, span }, _) => {
// FIXME: Handle `Invisible`-delimited groups in a more systematic way // FIXME: Handle `Invisible`-delimited groups in a more systematic way
// during parsing. // during parsing.
let mut next = outer_trees.next(); let mut next = outer_trees.next();
let mut trees: Box<dyn Iterator<Item = tokenstream::TokenTree>>; let mut trees: Box<dyn Iterator<Item = &tokenstream::TokenTree>>;
if let Some(tokenstream::TokenTree::Delimited(_, Delimiter::Invisible, tts)) = next { if let Some(tokenstream::TokenTree::Delimited(_, Delimiter::Invisible, tts)) = next {
trees = Box::new(tts.into_trees()); trees = Box::new(tts.trees());
next = trees.next(); next = trees.next();
} else { } else {
trees = Box::new(outer_trees); trees = Box::new(outer_trees);
@ -160,7 +160,7 @@ fn parse_tree(
match next { match next {
// `tree` is followed by a delimited set of token trees. // `tree` is followed by a delimited set of token trees.
Some(tokenstream::TokenTree::Delimited(delim_span, delim, tts)) => { Some(&tokenstream::TokenTree::Delimited(delim_span, delim, ref tts)) => {
if parsing_patterns { if parsing_patterns {
if delim != Delimiter::Parenthesis { if delim != Delimiter::Parenthesis {
span_dollar_dollar_or_metavar_in_the_lhs_err( span_dollar_dollar_or_metavar_in_the_lhs_err(
@ -228,7 +228,7 @@ fn parse_tree(
} }
// `tree` is followed by another `$`. This is an escaped `$`. // `tree` is followed by another `$`. This is an escaped `$`.
Some(tokenstream::TokenTree::Token(Token { kind: token::Dollar, span }, _)) => { Some(&tokenstream::TokenTree::Token(Token { kind: token::Dollar, span }, _)) => {
if parsing_patterns { if parsing_patterns {
span_dollar_dollar_or_metavar_in_the_lhs_err( span_dollar_dollar_or_metavar_in_the_lhs_err(
sess, sess,
@ -256,11 +256,11 @@ fn parse_tree(
} }
// `tree` is an arbitrary token. Keep it. // `tree` is an arbitrary token. Keep it.
tokenstream::TokenTree::Token(token, _) => TokenTree::Token(token), tokenstream::TokenTree::Token(token, _) => TokenTree::Token(token.clone()),
// `tree` is the beginning of a delimited set of tokens (e.g., `(` or `{`). We need to // `tree` is the beginning of a delimited set of tokens (e.g., `(` or `{`). We need to
// descend into the delimited set and further parse it. // descend into the delimited set and further parse it.
tokenstream::TokenTree::Delimited(span, delim, tts) => TokenTree::Delimited( &tokenstream::TokenTree::Delimited(span, delim, ref tts) => TokenTree::Delimited(
span, span,
Delimited { Delimited {
delim, delim,
@ -286,16 +286,16 @@ fn kleene_op(token: &Token) -> Option<KleeneOp> {
/// - Ok(Ok((op, span))) if the next token tree is a KleeneOp /// - Ok(Ok((op, span))) if the next token tree is a KleeneOp
/// - Ok(Err(tok, span)) if the next token tree is a token but not a KleeneOp /// - Ok(Err(tok, span)) if the next token tree is a token but not a KleeneOp
/// - Err(span) if the next token tree is not a token /// - Err(span) if the next token tree is not a token
fn parse_kleene_op( fn parse_kleene_op<'a>(
input: &mut impl Iterator<Item = tokenstream::TokenTree>, input: &mut impl Iterator<Item = &'a tokenstream::TokenTree>,
span: Span, span: Span,
) -> Result<Result<(KleeneOp, Span), Token>, Span> { ) -> Result<Result<(KleeneOp, Span), Token>, Span> {
match input.next() { match input.next() {
Some(tokenstream::TokenTree::Token(token, _)) => match kleene_op(&token) { Some(tokenstream::TokenTree::Token(token, _)) => match kleene_op(&token) {
Some(op) => Ok(Ok((op, token.span))), Some(op) => Ok(Ok((op, token.span))),
None => Ok(Err(token)), None => Ok(Err(token.clone())),
}, },
tree => Err(tree.as_ref().map_or(span, tokenstream::TokenTree::span)), tree => Err(tree.map_or(span, tokenstream::TokenTree::span)),
} }
} }
@ -311,8 +311,8 @@ fn parse_kleene_op(
/// session `sess`. If the next one (or possibly two) tokens in `input` correspond to a Kleene /// session `sess`. If the next one (or possibly two) tokens in `input` correspond to a Kleene
/// operator and separator, then a tuple with `(separator, KleeneOp)` is returned. Otherwise, an /// operator and separator, then a tuple with `(separator, KleeneOp)` is returned. Otherwise, an
/// error with the appropriate span is emitted to `sess` and a dummy value is returned. /// error with the appropriate span is emitted to `sess` and a dummy value is returned.
fn parse_sep_and_kleene_op( fn parse_sep_and_kleene_op<'a>(
input: &mut impl Iterator<Item = tokenstream::TokenTree>, input: &mut impl Iterator<Item = &'a tokenstream::TokenTree>,
span: Span, span: Span,
sess: &ParseSess, sess: &ParseSess,
) -> (Option<Token>, KleeneToken) { ) -> (Option<Token>, KleeneToken) {