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Rollup merge of #94316 - nnethercote:improve-string-literal-unescaping, r=petrochenkov

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Improve string literal unescaping

Some easy wins that affect a few popular crates.

r? ```@matklad```
This commit is contained in:
Dylan DPC 2022-02-24 21:42:18 +01:00 • committed by GitHub
commit ec44d48ae3
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3 changed files with 45 additions and 40 deletions
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1
compiler/rustc_ast/src/lib.rs
View file

@ -16,6 +16,7 @@
#![feature(min_specialization)]
#![recursion_limit = "256"]
#![feature(slice_internals)]
#![feature(stmt_expr_attributes)]
#[macro_use]
extern crate rustc_macros;

39
compiler/rustc_ast/src/util/literal.rs
View file

@ -56,25 +56,30 @@ impl LitKind {
// new symbol because the string in the LitKind is different to the
// string in the token.
let s = symbol.as_str();
let symbol =
if s.contains(&['\\', '\r']) {
let mut buf = String::with_capacity(s.len());
let mut error = Ok(());
unescape_literal(&s, Mode::Str, &mut |_, unescaped_char| {
match unescaped_char {
Ok(c) => buf.push(c),
Err(err) => {
if err.is_fatal() {
error = Err(LitError::LexerError);
}
let symbol = if s.contains(&['\\', '\r']) {
let mut buf = String::with_capacity(s.len());
let mut error = Ok(());
// Force-inlining here is aggressive but the closure is
// called on every char in the string, so it can be
// hot in programs with many long strings.
unescape_literal(
&s,
Mode::Str,
&mut #[inline(always)]
|_, unescaped_char| match unescaped_char {
Ok(c) => buf.push(c),
Err(err) => {
if err.is_fatal() {
error = Err(LitError::LexerError);
}
}
});
error?;
Symbol::intern(&buf)
} else {
symbol
};
},
);
error?;
Symbol::intern(&buf)
} else {
symbol
};
LitKind::Str(symbol, ast::StrStyle::Cooked)
}
token::StrRaw(n) => {