Auto merge of rust-lang#2439 - RalfJung:ptr-offset-from-unsigned, r=RalfJung

more tests for ptr_offset_from_unsinged

Author: bors

tests/fail/intrinsics/ptr_offset_from_unsigned_neg.rs

@@ -0,0 +1,9 @@
+//@error-pattern: first pointer has smaller offset than second: 0 < 4
+#![feature(ptr_sub_ptr)]
+
+fn main() {
+    let arr = [0u8; 8];
+    let ptr1 = arr.as_ptr();
+    let ptr2 = ptr1.wrapping_add(4);
+    let _val = unsafe { ptr1.sub_ptr(ptr2) };
+}

tests/fail/intrinsics/ptr_offset_from_unsigned_neg.stderr

@@ -0,0 +1,20 @@
+error: Undefined Behavior: ptr_offset_from_unsigned called when first pointer has smaller offset than second: 0 < 4
+  --> RUSTLIB/core/src/ptr/const_ptr.rs:LL:CC
+   |
+LL |         unsafe { intrinsics::ptr_offset_from_unsigned(self, origin) }
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ptr_offset_from_unsigned called when first pointer has smaller offset than second: 0 < 4
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: backtrace:
+   = note: inside `std::ptr::const_ptr::<impl *const u8>::sub_ptr` at RUSTLIB/core/src/ptr/const_ptr.rs:LL:CC
+note: inside `main` at $DIR/ptr_offset_from_unsigned_neg.rs:LL:CC
+  --> $DIR/ptr_offset_from_unsigned_neg.rs:LL:CC
+   |
+LL |     let _val = unsafe { ptr1.sub_ptr(ptr2) };
+   |                         ^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+

tests/pass/intrinsics.rs

@@ -1,6 +1,6 @@
 //@compile-flags: -Zmiri-permissive-provenance
-#![feature(core_intrinsics, const_raw_ptr_comparison)]
-#![feature(layout_for_ptr)]
+#![feature(core_intrinsics, layout_for_ptr)]
+//! Tests for various intrinsics that do not fit anywhere else.
 
 use std::intrinsics;
 use std::mem::{size_of, size_of_val, size_of_val_raw};
@@ -39,9 +39,4 @@ fn main() {
     let _v = intrinsics::discriminant_value(&0);
     let _v = intrinsics::discriminant_value(&true);
     let _v = intrinsics::discriminant_value(&vec![1, 2, 3]);
-
-    let addr = &13 as *const i32;
-    let addr2 = (addr as usize).wrapping_add(usize::MAX).wrapping_add(1);
-    assert!(addr.guaranteed_eq(addr2 as *const _));
-    assert!(addr.guaranteed_ne(0x100 as *const _));
 }

tests/pass/pointers.rs

@@ -1,4 +1,5 @@
-#![feature(ptr_metadata)]
+//@compile-flags: -Zmiri-permissive-provenance
+#![feature(ptr_metadata, const_raw_ptr_comparison)]
 
 use std::mem::{self, transmute};
 use std::ptr;
@@ -131,6 +132,12 @@ fn main() {
     assert!(dangling > 3);
     assert!(dangling >= 4);
 
+    // CTFE-specific equality tests, need to also work at runtime.
+    let addr = &13 as *const i32;
+    let addr2 = (addr as usize).wrapping_add(usize::MAX).wrapping_add(1);
+    assert!(addr.guaranteed_eq(addr2 as *const _));
+    assert!(addr.guaranteed_ne(0x100 as *const _));
+
     wide_ptr_ops();
     metadata_vtable();
 }

tests/pass/ptr_offset.rs

@@ -1,14 +1,30 @@
 //@compile-flags: -Zmiri-permissive-provenance
+#![feature(ptr_sub_ptr)]
 use std::{mem, ptr};
 
 fn main() {
+    smoke();
     test_offset_from();
     test_vec_into_iter();
     ptr_arith_offset();
     ptr_arith_offset_overflow();
     ptr_offset();
 }
 
+fn smoke() {
+    // Smoke-test various offsetting operations.
+    let ptr = &5;
+    let ptr = ptr as *const i32;
+    let _val = ptr.wrapping_offset(0);
+    let _val = unsafe { ptr.offset(0) };
+    let _val = ptr.wrapping_add(0);
+    let _val = unsafe { ptr.add(0) };
+    let _val = ptr.wrapping_sub(0);
+    let _val = unsafe { ptr.sub(0) };
+    let _val = unsafe { ptr.offset_from(ptr) };
+    let _val = unsafe { ptr.sub_ptr(ptr) };
+}
+
 fn test_offset_from() {
     unsafe {
         let buf = [0u32; 4];
@@ -17,12 +33,14 @@ fn test_offset_from() {
         let y = x.offset(12);
 
         assert_eq!(y.offset_from(x), 12);
+        assert_eq!(y.sub_ptr(x), 12);
         assert_eq!(x.offset_from(y), -12);
         assert_eq!((y as *const u32).offset_from(x as *const u32), 12 / 4);
         assert_eq!((x as *const u32).offset_from(y as *const u32), -12 / 4);
 
         let x = (((x as usize) * 2) / 2) as *const u8;
         assert_eq!(y.offset_from(x), 12);
+        assert_eq!(y.sub_ptr(x), 12);
         assert_eq!(x.offset_from(y), -12);
     }
 }