diff options
Diffstat (limited to 'src/liballoc')
| -rw-r--r-- | src/liballoc/heap.rs | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/src/liballoc/heap.rs b/src/liballoc/heap.rs index a2c406be5a9..b6c255e7930 100644 --- a/src/liballoc/heap.rs +++ b/src/liballoc/heap.rs @@ -86,10 +86,11 @@ pub fn stats_print() { imp::stats_print(); } -// The compiler never calls `exchange_free` on Box<ZeroSizeType>, so zero-size -// allocations can point to this `static`. It would be incorrect to use a null -// pointer, due to enums assuming types like unique pointers are never null. -pub static mut EMPTY: uint = 12345; +/// An arbitrary non-null address to represent zero-size allocations. +/// +/// This preserves the non-null invariant for types like `Box<T>`. The address may overlap with +/// non-zero-size memory allocations. +pub static EMPTY: *mut () = 0x1 as *mut (); /// The allocator for unique pointers. #[cfg(not(test))] @@ -97,7 +98,7 @@ pub static mut EMPTY: uint = 12345; #[inline] unsafe fn exchange_malloc(size: uint, align: uint) -> *mut u8 { if size == 0 { - &EMPTY as *const uint as *mut u8 + EMPTY as *mut u8 } else { allocate(size, align) } |