From e47fec56dd438c416ce45b06c9b3b23103c4ee3a Mon Sep 17 00:00:00 2001 From: Christopher Durham Date: Sat, 9 Nov 2019 13:43:11 -0500 Subject: [PATCH 1/2] Make Layout::new const --- src/libcore/alloc.rs | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/src/libcore/alloc.rs b/src/libcore/alloc.rs index b2d4b1b5fb916..37672888d0127 100644 --- a/src/libcore/alloc.rs +++ b/src/libcore/alloc.rs @@ -17,7 +17,7 @@ use crate::usize; #[derive(Debug)] pub struct Excess(pub NonNull, pub usize); -fn size_align() -> (usize, usize) { +const fn size_align() -> (usize, usize) { (mem::size_of::(), mem::align_of::()) } @@ -121,13 +121,12 @@ impl Layout { /// Constructs a `Layout` suitable for holding a value of type `T`. #[stable(feature = "alloc_layout", since = "1.28.0")] #[inline] - pub fn new() -> Self { + pub const fn new() -> Self { let (size, align) = size_align::(); // Note that the align is guaranteed by rustc to be a power of two and // the size+align combo is guaranteed to fit in our address space. As a // result use the unchecked constructor here to avoid inserting code // that panics if it isn't optimized well enough. - debug_assert!(Layout::from_size_align(size, align).is_ok()); unsafe { Layout::from_size_align_unchecked(size, align) } } From d860def8e2e2c807c37907c764b937ec35d4f2e6 Mon Sep 17 00:00:00 2001 From: CAD97 Date: Tue, 17 Dec 2019 14:55:46 -0500 Subject: [PATCH 2/2] Mark Layout::new as const stable --- src/libcore/alloc.rs | 1 + 1 file changed, 1 insertion(+) diff --git a/src/libcore/alloc.rs b/src/libcore/alloc.rs index 37672888d0127..163f9170b8bfb 100644 --- a/src/libcore/alloc.rs +++ b/src/libcore/alloc.rs @@ -120,6 +120,7 @@ impl Layout { /// Constructs a `Layout` suitable for holding a value of type `T`. #[stable(feature = "alloc_layout", since = "1.28.0")] + #[rustc_const_stable(feature = "alloc_layout_const_new", since = "1.42.0")] #[inline] pub const fn new() -> Self { let (size, align) = size_align::();