// This returns a miri pointer at type usize, if the argument is a proper pointer fn transmute_ptr_to_int(x: *const T) -> usize { unsafe { std::mem::transmute(x) } } fn cast() { // Some casting-to-int with arithmetic. let x = &42 as *const i32 as usize; let y = x * 2; assert_eq!(y, x + x); let z = y as u8 as usize; assert_eq!(z, y % 256); } fn format() { // Pointer string formatting! We can't check the output as it changes when libstd changes, // but we can make sure Miri does not error. format!("{:?}", &mut 13 as *mut _); } fn transmute() { // Check that intptrcast is triggered for explicit casts and that it is consistent with // transmuting. let a: *const i32 = &42; let b = transmute_ptr_to_int(a) as u8; let c = a as usize as u8; assert_eq!(b, c); } fn ptr_bitops1() { let bytes = [0i8, 1, 2, 3, 4, 5, 6, 7, 8, 9]; let one = bytes.as_ptr().wrapping_offset(1); let three = bytes.as_ptr().wrapping_offset(3); let res = (one as usize) | (three as usize); format!("{}", res); } fn ptr_bitops2() { let val = 13usize; let addr = &val as *const _ as usize; let _val = addr & 13; } fn ptr_eq_dangling() { let b = Box::new(0); let x = &*b as *const i32; // soon-to-be dangling drop(b); let b = Box::new(0); let y = &*b as *const i32; // different allocation // We cannot compare these even though both are inbounds -- they *could* be // equal if memory was reused. assert!(x != y); } fn ptr_eq_out_of_bounds() { let b = Box::new(0); let x = (&*b as *const i32).wrapping_sub(0x800); // out-of-bounds let b = Box::new(0); let y = &*b as *const i32; // different allocation // We cannot compare these even though both allocations are live -- they *could* be // equal (with the right base addresses). assert!(x != y); } fn ptr_eq_out_of_bounds_null() { let b = Box::new(0); let x = (&*b as *const i32).wrapping_sub(0x800); // out-of-bounds // We cannot compare this with NULL. After all, this *could* be NULL (with the right base address). assert!(x != std::ptr::null()); } fn ptr_eq_integer() { let b = Box::new(0); let x = &*b as *const i32; // We cannot compare this with a non-NULL integer. After all, these *could* be equal (with the right base address). assert!(x != 64 as *const i32); } fn main() { cast(); format(); transmute(); ptr_bitops1(); ptr_bitops2(); ptr_eq_dangling(); ptr_eq_out_of_bounds(); ptr_eq_out_of_bounds_null(); ptr_eq_integer(); }