From d5d389e4f11b1fad2d42453942f81271bbddee78 Mon Sep 17 00:00:00 2001 From: Nicholas Nethercote Date: Wed, 2 May 2018 11:50:21 +1000 Subject: [PATCH] Use escape_default() for strings in LitKind::token(). This avoids converting every char to \u{...} form, which bloats the resulting strings unnecessarily. It also provides consistency with the existing escape_default() calls in LitKind::token() used for raw string literals, char literals, and raw byte char literals. There are two benefits from this change. - Compilation is faster. Most of the rustc-perf benchmarks see a non-trivial speedup, particularly for incremental rebuilds, with the best speedup over 13%, and multiple others over 10%. - Generated rlibs are smaller. An extreme example is libfutures.rlib, which shrinks from 2073306 bytes to 1765927 bytes, a 15% reduction. --- src/libsyntax/attr.rs | 5 +---- src/libsyntax/lib.rs | 1 + 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr.rs index c68a743303a..05fabbee389 100644 --- a/src/libsyntax/attr.rs +++ b/src/libsyntax/attr.rs @@ -1228,10 +1228,7 @@ impl LitKind { match *self { LitKind::Str(string, ast::StrStyle::Cooked) => { - let mut escaped = String::new(); - for ch in string.as_str().chars() { - escaped.extend(ch.escape_unicode()); - } + let escaped = string.as_str().escape_default(); Token::Literal(token::Lit::Str_(Symbol::intern(&escaped)), None) } LitKind::Str(string, ast::StrStyle::Raw(n)) => { diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs index 870ce1926ad..f148aaf7267 100644 --- a/src/libsyntax/lib.rs +++ b/src/libsyntax/lib.rs @@ -25,6 +25,7 @@ #![feature(non_exhaustive)] #![feature(const_atomic_usize_new)] #![feature(rustc_attrs)] +#![feature(str_escape)] #![recursion_limit="256"]