From 0f68749260d04b61dfe2b38dbc423aefe2914a58 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <nnethercote@mozilla.com>
Date: Tue, 11 Dec 2018 09:06:51 +1100
Subject: Use a `newtype_index!` within `Symbol`.

This shrinks `Option<Symbol>` from 8 bytes to 4 bytes, which shrinks
`Token` from 24 bytes to 16 bytes. This reduces instruction counts by up
to 1% across a range of benchmarks.
---
 src/libsyntax/parse/token.rs | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'src/libsyntax')

diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index 6b9cc2f9792..83763bd32d4 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -207,6 +207,10 @@ pub enum Token {
     Eof,
 }
 
+// `Token` is used a lot. Make sure it doesn't unintentionally get bigger.
+#[cfg(target_arch = "x86_64")]
+static_assert!(MEM_SIZE_OF_STATEMENT: mem::size_of::<Token>() == 16);
+
 impl Token {
     pub fn interpolated(nt: Nonterminal) -> Token {
         Token::Interpolated(Lrc::new((nt, LazyTokenStream::new())))
-- 
cgit 1.4.1-3-g733a5