more precise error for 'based on misaligned pointer' case

tests/fail/const-ub-checks.stderr

@@ -2,7 +2,7 @@ error[E0080]: evaluation of constant value failed
   --> $DIR/const-ub-checks.rs:LL:CC
    |
 LL |     ptr.read();
-   |     ^^^^^^^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |     ^^^^^^^^^^ accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
 
 note: erroneous constant encountered
   --> $DIR/const-ub-checks.rs:LL:CC

tests/fail/dangling_pointers/out_of_bounds_read.rs

@@ -0,0 +1,8 @@
+#![feature(pointer_byte_offsets)]
+
+fn main() {
+    let v: Vec<u16> = vec![1, 2];
+    // This read is also misaligned. We make sure that the OOB message has priority.
+    let x = unsafe { *v.as_ptr().wrapping_byte_add(5) }; //~ ERROR: out-of-bounds
+    panic!("this should never print: {}", x);
+}

tests/fail/dangling_pointers/out_of_bounds_read1.stderr → tests/fail/dangling_pointers/out_of_bounds_read.stderr

@@ -1,18 +1,18 @@
-error: Undefined Behavior: memory access failed: ALLOC has size 2, so pointer to 1 byte starting at offset 5 is out-of-bounds
-  --> $DIR/out_of_bounds_read1.rs:LL:CC
+error: Undefined Behavior: memory access failed: ALLOC has size 4, so pointer to 2 bytes starting at offset 5 is out-of-bounds
+  --> $DIR/out_of_bounds_read.rs:LL:CC
    |
-LL |     let x = unsafe { *v.as_ptr().wrapping_offset(5) };
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: ALLOC has size 2, so pointer to 1 byte starting at offset 5 is out-of-bounds
+LL |     let x = unsafe { *v.as_ptr().wrapping_byte_add(5) };
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: ALLOC has size 4, so pointer to 2 bytes starting at offset 5 is out-of-bounds
    |
    = 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
 help: ALLOC was allocated here:
-  --> $DIR/out_of_bounds_read1.rs:LL:CC
+  --> $DIR/out_of_bounds_read.rs:LL:CC
    |
-LL |     let v: Vec<u8> = vec![1, 2];
-   |                      ^^^^^^^^^^
+LL |     let v: Vec<u16> = vec![1, 2];
+   |                       ^^^^^^^^^^
    = note: BACKTRACE (of the first span):
-   = note: inside `main` at $DIR/out_of_bounds_read1.rs:LL:CC
+   = note: inside `main` at $DIR/out_of_bounds_read.rs:LL:CC
    = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

tests/fail/dangling_pointers/out_of_bounds_write.rs

@@ -0,0 +1,7 @@
+#![feature(pointer_byte_offsets)]
+
+fn main() {
+    let mut v: Vec<u16> = vec![1, 2];
+    // This read is also misaligned. We make sure that the OOB message has priority.
+    unsafe { *v.as_mut_ptr().wrapping_byte_add(5) = 0 }; //~ ERROR: out-of-bounds
+}

tests/fail/dangling_pointers/out_of_bounds_read2.stderr → tests/fail/dangling_pointers/out_of_bounds_write.stderr

@@ -1,18 +1,18 @@
-error: Undefined Behavior: memory access failed: ALLOC has size 2, so pointer to 1 byte starting at offset 5 is out-of-bounds
-  --> $DIR/out_of_bounds_read2.rs:LL:CC
+error: Undefined Behavior: memory access failed: ALLOC has size 4, so pointer to 2 bytes starting at offset 5 is out-of-bounds
+  --> $DIR/out_of_bounds_write.rs:LL:CC
    |
-LL |     let x = unsafe { *v.as_ptr().wrapping_offset(5) };
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: ALLOC has size 2, so pointer to 1 byte starting at offset 5 is out-of-bounds
+LL |     unsafe { *v.as_mut_ptr().wrapping_byte_add(5) = 0 };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: ALLOC has size 4, so pointer to 2 bytes starting at offset 5 is out-of-bounds
    |
    = 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
 help: ALLOC was allocated here:
-  --> $DIR/out_of_bounds_read2.rs:LL:CC
+  --> $DIR/out_of_bounds_write.rs:LL:CC
    |
-LL |     let v: Vec<u8> = vec![1, 2];
-   |                      ^^^^^^^^^^
+LL |     let mut v: Vec<u16> = vec![1, 2];
+   |                           ^^^^^^^^^^
    = note: BACKTRACE (of the first span):
-   = note: inside `main` at $DIR/out_of_bounds_read2.rs:LL:CC
+   = note: inside `main` at $DIR/out_of_bounds_write.rs:LL:CC
    = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

tests/fail/unaligned_pointers/alignment.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+error: Undefined Behavior: accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
   --> $DIR/alignment.rs:LL:CC
    |
 LL |         *(x_ptr as *mut u32) = 42; *(x_ptr.add(1) as *mut u32) = 42;
-   | ^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   | ^ accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
    |
    = 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

tests/fail/unaligned_pointers/field_requires_parent_struct_alignment.rs

@@ -8,7 +8,7 @@ pub struct S {
 }
 
 unsafe fn foo(x: *const S) -> u8 {
-    unsafe { (*x).x } //~ERROR: accessing memory with alignment 1, but alignment 4 is required
+    unsafe { (*x).x } //~ERROR: based on pointer with alignment 1, but alignment 4 is required
 }
 
 fn main() {

tests/fail/unaligned_pointers/field_requires_parent_struct_alignment.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+error: Undefined Behavior: accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
   --> $DIR/field_requires_parent_struct_alignment.rs:LL:CC
    |
 LL |     unsafe { (*x).x }
-   |              ^^^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |              ^^^^^^ accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
    |
    = 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

tests/fail/unaligned_pointers/field_requires_parent_struct_alignment2.rs

@@ -15,7 +15,7 @@ pub struct Packed {
 }
 
 unsafe fn foo(x: *const Aligned) -> u8 {
-    unsafe { (*x).packed.x } //~ERROR: accessing memory with alignment 1, but alignment 16 is required
+    unsafe { (*x).packed.x } //~ERROR: based on pointer with alignment 1, but alignment 16 is required
 }
 
 fn main() {

tests/fail/unaligned_pointers/field_requires_parent_struct_alignment2.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+error: Undefined Behavior: accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
   --> $DIR/field_requires_parent_struct_alignment2.rs:LL:CC
    |
 LL |     unsafe { (*x).packed.x }
-   |              ^^^^^^^^^^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |              ^^^^^^^^^^^^^ accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
    |
    = 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

tests/fail/unaligned_pointers/intptrcast_alignment_check.rs

@@ -12,6 +12,6 @@ fn main() {
     // Manually make sure the pointer is properly aligned.
     let base_addr_aligned = if base_addr % 2 == 0 { base_addr } else { base_addr + 1 };
     let u16_ptr = base_addr_aligned as *mut u16;
-    unsafe { *u16_ptr = 2 }; //~ERROR: memory with alignment 1, but alignment 2 is required
+    unsafe { *u16_ptr = 2 }; //~ERROR: with alignment 1, but alignment 2 is required
     println!("{:?}", x);
 }

tests/fail/unaligned_pointers/intptrcast_alignment_check.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+error: Undefined Behavior: accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
   --> $DIR/intptrcast_alignment_check.rs:LL:CC
    |
 LL |     unsafe { *u16_ptr = 2 };
-   |              ^^^^^^^^^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |              ^^^^^^^^^^^^ accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
    |
    = help: this usually indicates that your program performed an invalid operation and caused Undefined Behavior
    = help: but due to `-Zmiri-symbolic-alignment-check`, alignment errors can also be false positives

tests/fail/unaligned_pointers/unaligned_ptr1.rs

@@ -7,6 +7,6 @@ fn main() {
         let x = [2u16, 3, 4]; // Make it big enough so we don't get an out-of-bounds error.
         let x = &x[0] as *const _ as *const u32;
         // This must fail because alignment is violated: the allocation's base is not sufficiently aligned.
-        let _x = unsafe { *x }; //~ERROR: memory with alignment 2, but alignment 4 is required
+        let _x = unsafe { *x }; //~ERROR: with alignment 2, but alignment 4 is required
     }
 }

tests/fail/unaligned_pointers/unaligned_ptr1.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+error: Undefined Behavior: accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
   --> $DIR/unaligned_ptr1.rs:LL:CC
    |
 LL |         let _x = unsafe { *x };
-   |                           ^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |                           ^^ accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
    |
    = 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

tests/fail/unaligned_pointers/unaligned_ptr2.rs

@@ -8,5 +8,5 @@ fn main() {
     let x = (x.as_ptr() as *const u8).wrapping_offset(3) as *const u32;
     // This must fail because alignment is violated: the offset is not sufficiently aligned.
     // Also make the offset not a power of 2, that used to ICE.
-    let _x = unsafe { *x }; //~ERROR: memory with alignment 1, but alignment 4 is required
+    let _x = unsafe { *x }; //~ERROR: with alignment 1, but alignment 4 is required
 }

tests/fail/unaligned_pointers/unaligned_ptr2.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+error: Undefined Behavior: accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
   --> $DIR/unaligned_ptr2.rs:LL:CC
    |
 LL |     let _x = unsafe { *x };
-   |                       ^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |                       ^^ accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
    |
    = 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

tests/fail/unaligned_pointers/unaligned_ptr3.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+error: Undefined Behavior: accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
   --> $DIR/unaligned_ptr3.rs:LL:CC
    |
 LL |         let _x = unsafe { *x };
-   |                           ^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |                           ^^ accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
    |
    = 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

tests/fail/unaligned_pointers/unaligned_ptr4.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+error: Undefined Behavior: accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
   --> $DIR/unaligned_ptr4.rs:LL:CC
    |
 LL |         let _val = unsafe { *ptr };
-   |                             ^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |                             ^^^^ accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
    |
    = 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

tests/fail/unaligned_pointers/unaligned_ptr_zst.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+error: Undefined Behavior: accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
   --> $DIR/unaligned_ptr_zst.rs:LL:CC
    |
 LL |         let _x = unsafe { *x };
-   |                           ^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |                           ^^ accessing memory based on pointer with alignment ALIGN, but alignment ALIGN is required
    |
    = 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