mirror of https://github.com/rust-lang/rust
44 lines
1.5 KiB
Rust
44 lines
1.5 KiB
Rust
//@ compile-flags: --crate-type=lib
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//@ check-pass
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#![feature(
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core_intrinsics,
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const_raw_ptr_comparison,
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)]
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const FOO: &usize = &42;
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macro_rules! check {
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(eq, $a:expr, $b:expr) => {
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pub const _: () =
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assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 1);
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};
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(ne, $a:expr, $b:expr) => {
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pub const _: () =
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assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 0);
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};
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(!, $a:expr, $b:expr) => {
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pub const _: () =
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assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 2);
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};
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}
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check!(eq, 0, 0);
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check!(ne, 0, 1);
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check!(ne, FOO as *const _, 0);
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check!(ne, unsafe { (FOO as *const usize).offset(1) }, 0);
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check!(ne, unsafe { (FOO as *const usize as *const u8).offset(3) }, 0);
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// We want pointers to be equal to themselves, but aren't checking this yet because
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// there are some open questions (e.g. whether function pointers to the same function
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// compare equal: they don't necessarily do at runtime).
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check!(!, FOO as *const _, FOO as *const _);
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// aside from 0, these pointers might end up pretty much anywhere.
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check!(!, FOO as *const _, 1); // this one could be `ne` by taking into account alignment
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check!(!, FOO as *const _, 1024);
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// When pointers go out-of-bounds, they *might* become null, so these comparions cannot work.
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check!(!, unsafe { (FOO as *const usize).wrapping_add(2) }, 0);
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check!(!, unsafe { (FOO as *const usize).wrapping_sub(1) }, 0);
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