OpenE2K
/
rust
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Rollup merge of #66755 - mark-i-m:const-vec-new, r=ecstatic-morse 

Remove a const-if-hack in RawVec

r? @ecstatic-morse

cc @Centril
This commit is contained in:
Mazdak Farrokhzad 2019-12-20 12:17:18 +01:00 committed by GitHub
parent 696735f71b 7d268119f0
commit 57da9d3269
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 4 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/liballoc/lib.rs
View File

@ -85,6 +85,7 @@
#![feature(const_generic_impls_guard)] #![feature(const_generic_impls_guard)]
#![feature(const_generics)] #![feature(const_generics)]
#![feature(const_in_array_repeat_expressions)] #![feature(const_in_array_repeat_expressions)]
#![feature(const_if_match)]
#![feature(cow_is_borrowed)] #![feature(cow_is_borrowed)]
#![feature(dispatch_from_dyn)] #![feature(dispatch_from_dyn)]
#![feature(core_intrinsics)] #![feature(core_intrinsics)]

21
src/liballoc/raw_vec.rs
View File

@ -52,15 +52,12 @@ impl<T, A: Alloc> RawVec<T, A> {
/// Like `new`, but parameterized over the choice of allocator for /// Like `new`, but parameterized over the choice of allocator for
/// the returned `RawVec`. /// the returned `RawVec`.
pub const fn new_in(a: A) -> Self { pub const fn new_in(a: A) -> Self {
// `!0` is `usize::MAX`. This branch should be stripped at compile time. let cap = if mem::size_of::<T>() == 0 { core::usize::MAX } else { 0 };
// FIXME(mark-i-m): use this line when `if`s are allowed in `const`:
//let cap = if mem::size_of::<T>() == 0 { !0 } else { 0 };
// `Unique::empty()` doubles as "unallocated" and "zero-sized allocation". // `Unique::empty()` doubles as "unallocated" and "zero-sized allocation".
RawVec { RawVec {
ptr: Unique::empty(), ptr: Unique::empty(),
// FIXME(mark-i-m): use `cap` when ifs are allowed in const cap,
cap: [0, !0][(mem::size_of::<T>() == 0) as usize],
a, a,
} }
} }
@ -132,19 +129,7 @@ impl<T> RawVec<T, Global> {
/// `RawVec` with capacity `usize::MAX`. Useful for implementing /// `RawVec` with capacity `usize::MAX`. Useful for implementing
/// delayed allocation. /// delayed allocation.
pub const fn new() -> Self { pub const fn new() -> Self {
// FIXME(Centril): Reintegrate this with `fn new_in` when we can. Self::new_in(Global)
// `!0` is `usize::MAX`. This branch should be stripped at compile time.
// FIXME(mark-i-m): use this line when `if`s are allowed in `const`:
//let cap = if mem::size_of::<T>() == 0 { !0 } else { 0 };
// `Unique::empty()` doubles as "unallocated" and "zero-sized allocation".
RawVec {
ptr: Unique::empty(),
// FIXME(mark-i-m): use `cap` when ifs are allowed in const
cap: [0, !0][(mem::size_of::<T>() == 0) as usize],
a: Global,
}
} }
/// Creates a `RawVec` (on the system heap) with exactly the /// Creates a `RawVec` (on the system heap) with exactly the