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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/consts/offset.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/consts/offset.rs')
-rw-r--r-- | src/test/ui/consts/offset.rs | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/src/test/ui/consts/offset.rs b/src/test/ui/consts/offset.rs new file mode 100644 index 000000000..f9ddda554 --- /dev/null +++ b/src/test/ui/consts/offset.rs @@ -0,0 +1,113 @@ +// run-pass +#![feature(const_ptr_offset_from)] +use std::ptr; + +#[repr(C)] +struct Struct { + a: u32, + b: u32, + c: u32, +} +static S: Struct = Struct { a: 0, b: 0, c: 0 }; + +// For these tests we use offset_from to check that two pointers are equal. +// Rust doesn't currently support comparing pointers in const fn. + +static OFFSET_NO_CHANGE: bool = unsafe { + let p1 = &S.b as *const u32; + let p2 = p1.offset(2).offset(-2); + p1.offset_from(p2) == 0 +}; +static OFFSET_MIDDLE: bool = unsafe { + let p1 = (&S.a as *const u32).offset(1); + let p2 = (&S.c as *const u32).offset(-1); + p1.offset_from(p2) == 0 +}; +// Pointing to the end of the allocation is OK +static OFFSET_END: bool = unsafe { + let p1 = (&S.a as *const u32).offset(3); + let p2 = (&S.c as *const u32).offset(1); + p1.offset_from(p2) == 0 +}; +// Casting though a differently sized type is OK +static OFFSET_U8_PTR: bool = unsafe { + let p1 = (&S.a as *const u32 as *const u8).offset(5); + let p2 = (&S.c as *const u32 as *const u8).offset(-3); + p1.offset_from(p2) == 0 +}; +// Any offset with a ZST does nothing +const OFFSET_ZST: bool = unsafe { + let pz = &() as *const (); + // offset_from can't work with ZSTs, so cast to u8 ptr + let p1 = pz.offset(5) as *const u8; + let p2 = pz.offset(isize::MIN) as *const u8; + p1.offset_from(p2) == 0 +}; +const OFFSET_ZERO: bool = unsafe { + let p = [0u8; 0].as_ptr(); + p.offset(0).offset_from(p) == 0 +}; +const OFFSET_ONE: bool = unsafe { + let p = &42u32 as *const u32; + p.offset(1).offset_from(p) == 1 +}; +const OFFSET_DANGLING: bool = unsafe { + let p = ptr::NonNull::<u8>::dangling().as_ptr(); + p.offset(0).offset_from(p) == 0 +}; +const OFFSET_UNALIGNED: bool = unsafe { + let arr = [0u8; 32]; + let p1 = arr.as_ptr(); + let p2 = (p1.offset(2) as *const u32).offset(1); + (p2 as *const u8).offset_from(p1) == 6 +}; + +const WRAP_OFFSET_NO_CHANGE: bool = unsafe { + let p1 = &42u32 as *const u32; + let p2 = p1.wrapping_offset(1000).wrapping_offset(-1000); + let p3 = p1.wrapping_offset(-1000).wrapping_offset(1000); + (p1.offset_from(p2) == 0) & (p1.offset_from(p3) == 0) +}; +const WRAP_ADDRESS_SPACE: bool = unsafe { + let p1 = &42u8 as *const u8; + let p2 = p1.wrapping_offset(isize::MIN).wrapping_offset(isize::MIN); + p1.offset_from(p2) == 0 +}; +// Wrap on the count*size_of::<T>() calculation. +const WRAP_SIZE_OF: bool = unsafe { + // Make sure that if p1 moves backwards, we are still in range + let arr = [0u32; 2]; + let p = &arr[1] as *const u32; + // With wrapping arithmetic, isize::MAX * 4 == -4 + let wrapped = p.wrapping_offset(isize::MAX); + let backward = p.wrapping_offset(-1); + wrapped.offset_from(backward) == 0 +}; +const WRAP_INTEGER_POINTER: bool = unsafe { + let p1 = (0x42 as *const u32).wrapping_offset(4); + let p2 = 0x52 as *const u32; + p1.offset_from(p2) == 0 +}; +const WRAP_NULL: bool = unsafe { + let p1 = ptr::null::<u32>().wrapping_offset(1); + let p2 = 0x4 as *const u32; + p1.offset_from(p2) == 0 +}; + +fn main() { + assert!(OFFSET_NO_CHANGE); + assert!(OFFSET_MIDDLE); + assert!(OFFSET_END); + assert!(OFFSET_U8_PTR); + assert!(OFFSET_ZST); + assert!(OFFSET_ZERO); + assert!(OFFSET_ONE); + assert!(OFFSET_DANGLING); + assert!(OFFSET_UNALIGNED); + + assert!(WRAP_OFFSET_NO_CHANGE); + assert!(WRAP_ADDRESS_SPACE); + assert!(WRAP_SIZE_OF); + assert!(WRAP_INTEGER_POINTER); + assert!(WRAP_NULL); +} |