Rollup merge of #136438 - RalfJung:offset_from_ub_errors, r=oli-obk

miri: improve error when offset_from preconditions are violated

Fixes https://github.com/rust-lang/miri/issues/4143

6 files changed, 45 insertions, 3 deletions

diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_allocs.rs b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_allocs.rs
new file mode 100644
index 00000000000..5a997ad8ec4
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_allocs.rs
@@ -0,0 +1,5 @@
+fn main() {
+    unsafe {
+        (&1_u8 as *const u8).offset_from(&2_u8); //~ERROR: not both derived from the same allocation
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_allocs.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_allocs.stderr
new file mode 100644
index 00000000000..34d7c6a8021
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_allocs.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `ptr_offset_from` called on two different pointers that are not both derived from the same allocation
+  --> tests/fail/intrinsics/ptr_offset_from_different_allocs.rs:LL:CC
+   |
+LL |         (&1_u8 as *const u8).offset_from(&2_u8);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `ptr_offset_from` called on two different pointers that are not both derived from the same allocation
+   |
+   = 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 `main` at tests/fail/intrinsics/ptr_offset_from_different_allocs.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_ints.rs b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_ints.rs
index 0acda559d3a..0d34e711ca7 100644
--- a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_ints.rs
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_ints.rs
@@ -15,6 +15,6 @@ fn main() {
         let _ = p1.byte_offset_from(p1);
 
         // UB because different pointers.
-        let _ = p1.byte_offset_from(p2); //~ERROR: no provenance
+        let _ = p1.byte_offset_from(p2); //~ERROR: not both derived from the same allocation
     }
 }
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_ints.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_ints.stderr
index 7ef66390fcd..897945d6d5d 100644
--- a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_ints.stderr
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_different_ints.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: out-of-bounds `offset_from` origin: expected a pointer to the end of 1 byte of memory, but got 0xb[noalloc] which is a dangling pointer (it has no provenance)
+error: Undefined Behavior: `ptr_offset_from` called on two different pointers that are not both derived from the same allocation
   --> tests/fail/intrinsics/ptr_offset_from_different_ints.rs:LL:CC
    |
 LL |         let _ = p1.byte_offset_from(p2);
-   |                 ^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds `offset_from` origin: expected a pointer to the end of 1 byte of memory, but got 0xb[noalloc] which is a dangling pointer (it has no provenance)
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^ `ptr_offset_from` called on two different pointers that are not both derived from the same allocation
    |
    = 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
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.rs b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.rs
new file mode 100644
index 00000000000..06f6b7a0117
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.rs
@@ -0,0 +1,7 @@
+fn main() {
+    let mem = [0u8; 1];
+    let ptr = mem.as_ptr();
+    unsafe {
+        ptr.wrapping_add(4).offset_from(ptr); //~ERROR: the memory range between them is not in-bounds of an allocation
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.stderr
new file mode 100644
index 00000000000..67df633bef5
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `ptr_offset_from` called on two different pointers where the memory range between them is not in-bounds of an allocation
+  --> tests/fail/intrinsics/ptr_offset_from_oob.rs:LL:CC
+   |
+LL |         ptr.wrapping_add(4).offset_from(ptr);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `ptr_offset_from` called on two different pointers where the memory range between them is not in-bounds of an allocation
+   |
+   = 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 `main` at tests/fail/intrinsics/ptr_offset_from_oob.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+