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Change String to &'static str in ParseResult::Failure.

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This avoids 770,000 allocations when compiling the `html5ever`
benchmark, reducing instruction counts by up to 2%.
This commit is contained in:
Nicholas Nethercote 2019-01-09 15:16:19 +11:00
parent b92552d557
commit 46fa818d34
2 changed files with 4 additions and 4 deletions
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6
src/libsyntax/ext/tt/macro_parser.rs
View file

@ -271,7 +271,7 @@ pub enum ParseResult<T> {
Success(T),
/// Arm failed to match. If the second parameter is `token::Eof`, it indicates an unexpected
/// end of macro invocation. Otherwise, it indicates that no rules expected the given token.
Failure(syntax_pos::Span, Token, String),
Failure(syntax_pos::Span, Token, &'static str),
/// Fatal error (malformed macro?). Abort compilation.
Error(syntax_pos::Span, String),
}
@ -721,7 +721,7 @@ pub fn parse(
sess.source_map().next_point(parser.span)
},
token::Eof,
"missing tokens in macro arguments".to_string(),
"missing tokens in macro arguments",
);
}
}
@ -760,7 +760,7 @@ pub fn parse(
return Failure(
parser.span,
parser.token,
"no rules expected this token in macro call".to_string(),
"no rules expected this token in macro call",
);
}
// Dump all possible `next_items` into `cur_items` for the next iteration.

2
src/libsyntax/ext/tt/macro_rules.rs
View file

@ -202,7 +202,7 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
let best_fail_msg = parse_failure_msg(best_fail_tok.expect("ran no matchers"));
let span = best_fail_spot.substitute_dummy(sp);
let mut err = cx.struct_span_err(span, &best_fail_msg);
err.span_label(span, best_fail_text.unwrap_or(best_fail_msg));
err.span_label(span, best_fail_text.unwrap_or(&best_fail_msg));
if let Some(sp) = def_span {
if cx.source_map().span_to_filename(sp).is_real() && !sp.is_dummy() {
err.span_label(cx.source_map().def_span(sp), "when calling this macro");