Rollup merge of #142673 - oli-obk:uninit-read-mem, r=RalfJung

Show the offset, length and memory of uninit read errors

r? ``@RalfJung``

I want to improve memory dumps in general. Not sure yet how to do so best within rust diagnostics, but in a perfect world I could generate a dummy in-memory file (that contains the rendered memory dump) that we then can then provide regular rustc `Span`s to. So we'd basically report normal diagnostics for them with squiggly lines and everything.

35 files changed, 152 insertions, 31 deletions

diff --git a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.rs b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.rs
index 047fe07df14..5778765589d 100644
--- a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.rs
+++ b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.rs
@@ -1,4 +1,6 @@
 //@ignore-target: windows # No pthreads on Windows
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
 
 /// Test that destroying a pthread_cond twice fails, even without a check for number validity
 
@@ -15,6 +17,6 @@ fn main() {
         libc::pthread_cond_destroy(cond.as_mut_ptr());
 
         libc::pthread_cond_destroy(cond.as_mut_ptr());
-        //~^ ERROR: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+        //~^ ERROR: /Undefined Behavior: reading memory .*, but memory is uninitialized/
     }
 }
diff --git a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.stderr b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.stderr
index 7abdfa87f75..6156070cf95 100644
--- a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.stderr
+++ b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.rs:LL:CC
    |
 LL |         libc::pthread_cond_destroy(cond.as_mut_ptr());
@@ -9,6 +9,9 @@ LL |         libc::pthread_cond_destroy(cond.as_mut_ptr());
    = note: BACKTRACE:
    = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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-dep/concurrency/libc_pthread_condattr_double_destroy.rs b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.rs
index 90e33d58673..91169660491 100644
--- a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.rs
+++ b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.rs
@@ -1,5 +1,7 @@
 //@ignore-target: windows # No pthreads on Windows
 //@ignore-target: apple # Our macOS condattr don't have any fields so we do not notice this.
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
 
 /// Test that destroying a pthread_condattr twice fails, even without a check for number validity
 
@@ -13,6 +15,6 @@ fn main() {
         libc::pthread_condattr_destroy(attr.as_mut_ptr());
 
         libc::pthread_condattr_destroy(attr.as_mut_ptr());
-        //~^ ERROR: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+        //~^ ERROR: /Undefined Behavior: reading memory .*, but memory is uninitialized/
     }
 }
diff --git a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.stderr b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.stderr
index 28a66253ae8..da64970ff2e 100644
--- a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.stderr
+++ b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.rs:LL:CC
    |
 LL |         libc::pthread_condattr_destroy(attr.as_mut_ptr());
@@ -9,6 +9,9 @@ LL |         libc::pthread_condattr_destroy(attr.as_mut_ptr());
    = note: BACKTRACE:
    = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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-dep/concurrency/libc_pthread_mutex_double_destroy.rs b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.rs
index 1792c227e13..f04fe8be6b3 100644
--- a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.rs
+++ b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.rs
@@ -1,4 +1,6 @@
 //@ignore-target: windows # No pthreads on Windows
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
 
 /// Test that destroying a pthread_mutex twice fails, even without a check for number validity
 
@@ -16,6 +18,6 @@ fn main() {
         libc::pthread_mutex_destroy(mutex.as_mut_ptr());
 
         libc::pthread_mutex_destroy(mutex.as_mut_ptr());
-        //~^ ERROR: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+        //~^ ERROR: /Undefined Behavior: reading memory .*, but memory is uninitialized/
     }
 }
diff --git a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.stderr b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.stderr
index e7a6dee0203..05db823b252 100644
--- a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.stderr
+++ b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.rs:LL:CC
    |
 LL |         libc::pthread_mutex_destroy(mutex.as_mut_ptr());
@@ -9,6 +9,9 @@ LL |         libc::pthread_mutex_destroy(mutex.as_mut_ptr());
    = note: BACKTRACE:
    = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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-dep/concurrency/libc_pthread_mutexattr_double_destroy.rs b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.rs
index 3711c1f8dc1..d9daf5259bb 100644
--- a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.rs
+++ b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.rs
@@ -1,4 +1,6 @@
 //@ignore-target: windows # No pthreads on Windows
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
 
 /// Test that destroying a pthread_mutexattr twice fails, even without a check for number validity
 
@@ -12,6 +14,6 @@ fn main() {
         libc::pthread_mutexattr_destroy(attr.as_mut_ptr());
 
         libc::pthread_mutexattr_destroy(attr.as_mut_ptr());
-        //~^ ERROR: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+        //~^ ERROR: /Undefined Behavior: reading memory .*, but memory is uninitialized/
     }
 }
diff --git a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.stderr b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.stderr
index 0c9ee71de45..ee3883de36b 100644
--- a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.stderr
+++ b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.rs:LL:CC
    |
 LL |         libc::pthread_mutexattr_destroy(attr.as_mut_ptr());
@@ -9,6 +9,9 @@ LL |         libc::pthread_mutexattr_destroy(attr.as_mut_ptr());
    = note: BACKTRACE:
    = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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-dep/concurrency/libc_pthread_rwlock_double_destroy.rs b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.rs
index 6a31e972e68..720ba71d238 100644
--- a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.rs
+++ b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.rs
@@ -1,4 +1,6 @@
 //@ignore-target: windows # No pthreads on Windows
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
 
 /// Test that destroying a pthread_rwlock twice fails, even without a check for number validity
 
@@ -9,6 +11,6 @@ fn main() {
         libc::pthread_rwlock_destroy(&mut lock);
 
         libc::pthread_rwlock_destroy(&mut lock);
-        //~^ ERROR: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+        //~^ ERROR: /Undefined Behavior: reading memory .*, but memory is uninitialized/
     }
 }
diff --git a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.stderr b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.stderr
index 836f0d060bd..430398dc8fd 100644
--- a/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.stderr
+++ b/src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.rs:LL:CC
    |
 LL |         libc::pthread_rwlock_destroy(&mut lock);
@@ -9,6 +9,9 @@ LL |         libc::pthread_rwlock_destroy(&mut lock);
    = note: BACKTRACE:
    = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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/function_calls/arg_inplace_observe_after.stderr b/src/tools/miri/tests/fail/function_calls/arg_inplace_observe_after.stderr
index 6a7d9a495f9..3252368ea6d 100644
--- a/src/tools/miri/tests/fail/function_calls/arg_inplace_observe_after.stderr
+++ b/src/tools/miri/tests/fail/function_calls/arg_inplace_observe_after.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0x0..0x4], but memory is uninitialized at [0x0..0x4], and this operation requires initialized memory
   --> tests/fail/function_calls/arg_inplace_observe_after.rs:LL:CC
    |
 LL |             _observe = non_copy.0;
@@ -9,6 +9,11 @@ LL |             _observe = non_copy.0;
    = note: BACKTRACE:
    = note: inside `main` at tests/fail/function_calls/arg_inplace_observe_after.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0x0..0x4], in this allocation:
+ALLOC (stack variable, size: 4, align: 4) {
+    __ __ __ __                                     │ ░░░░
+}
+
 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/function_calls/arg_inplace_observe_during.none.stderr b/src/tools/miri/tests/fail/function_calls/arg_inplace_observe_during.none.stderr
index 0fc634bb7fc..09a5b9a6496 100644
--- a/src/tools/miri/tests/fail/function_calls/arg_inplace_observe_during.none.stderr
+++ b/src/tools/miri/tests/fail/function_calls/arg_inplace_observe_during.none.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0x0..0x4], but memory is uninitialized at [0x0..0x4], and this operation requires initialized memory
   --> tests/fail/function_calls/arg_inplace_observe_during.rs:LL:CC
    |
 LL |     unsafe { ptr.read() };
@@ -14,6 +14,11 @@ note: inside `main`
 LL |             Call(_unit = change_arg(Move(*ptr), ptr), ReturnTo(after_call), UnwindContinue())
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+Uninitialized memory occurred at ALLOC[0x0..0x4], in this allocation:
+ALLOC (stack variable, size: 4, align: 4) {
+    __ __ __ __                                     │ ░░░░
+}
+
 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/function_calls/return_pointer_aliasing_read.none.stderr b/src/tools/miri/tests/fail/function_calls/return_pointer_aliasing_read.none.stderr
index 746ab2e59ca..24091547258 100644
--- a/src/tools/miri/tests/fail/function_calls/return_pointer_aliasing_read.none.stderr
+++ b/src/tools/miri/tests/fail/function_calls/return_pointer_aliasing_read.none.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0x0..0x4], but memory is uninitialized at [0x0..0x4], and this operation requires initialized memory
   --> tests/fail/function_calls/return_pointer_aliasing_read.rs:LL:CC
    |
 LL |     unsafe { ptr.read() };
@@ -14,6 +14,11 @@ note: inside `main`
 LL |             Call(*ptr = myfun(ptr), ReturnTo(after_call), UnwindContinue())
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+Uninitialized memory occurred at ALLOC[0x0..0x4], in this allocation:
+ALLOC (stack variable, size: 4, align: 4) {
+    __ __ __ __                                     │ ░░░░
+}
+
 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/function_calls/return_pointer_on_unwind.stderr b/src/tools/miri/tests/fail/function_calls/return_pointer_on_unwind.stderr
index 7747a75d1cf..93720ca7d27 100644
--- a/src/tools/miri/tests/fail/function_calls/return_pointer_on_unwind.stderr
+++ b/src/tools/miri/tests/fail/function_calls/return_pointer_on_unwind.stderr
@@ -3,7 +3,7 @@ thread 'main' panicked at tests/fail/function_calls/return_pointer_on_unwind.rs:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0x0..0x4], but memory is uninitialized at [0x0..0x4], and this operation requires initialized memory
   --> tests/fail/function_calls/return_pointer_on_unwind.rs:LL:CC
    |
 LL |     dbg!(x.0);
@@ -15,6 +15,19 @@ LL |     dbg!(x.0);
    = note: inside `main` at RUSTLIB/std/src/macros.rs:LL:CC
    = note: this error originates in the macro `dbg` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+Uninitialized memory occurred at ALLOC[0x0..0x4], in this allocation:
+ALLOC (stack variable, size: 132, align: 4) {
+    0x00 │ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
+    0x10 │ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
+    0x20 │ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
+    0x30 │ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
+    0x40 │ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
+    0x50 │ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
+    0x60 │ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
+    0x70 │ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
+    0x80 │ __ __ __ __                                     │ ░░░░
+}
+
 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_metadata_uninit_slice_data.rs b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_data.rs
index 0c305eed6e1..c03e468cfba 100644
--- a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_data.rs
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_data.rs
@@ -1,4 +1,7 @@
 //@compile-flags: -Zmiri-disable-validation
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
+
 #![feature(core_intrinsics, custom_mir)]
 use std::intrinsics::mir::*;
 
@@ -9,7 +12,7 @@ use std::intrinsics::mir::*;
 pub unsafe fn deref_meta(p: *const *const [i32]) -> usize {
     mir! {
         {
-            RET = PtrMetadata(*p); //~ ERROR: Undefined Behavior: using uninitialized data
+            RET = PtrMetadata(*p); //~ ERROR: /Undefined Behavior: .* but memory is uninitialized/
             Return()
         }
     }
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_data.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_data.stderr
index 1c22876ba43..1e7f500edb2 100644
--- a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_data.stderr
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_data.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail/intrinsics/ptr_metadata_uninit_slice_data.rs:LL:CC
    |
 LL |             RET = PtrMetadata(*p);
@@ -14,6 +14,9 @@ note: inside `main`
 LL |         let _meta = deref_meta(p.as_ptr().cast());
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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_metadata_uninit_slice_len.rs b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_len.rs
index a2ffdc92c4e..7053c0f6e18 100644
--- a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_len.rs
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_len.rs
@@ -1,4 +1,7 @@
 //@compile-flags: -Zmiri-disable-validation
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]+..0x[0-9a-z]+\]" -> "[0xX..0xY]"
+
 #![feature(core_intrinsics, custom_mir)]
 use std::intrinsics::mir::*;
 
@@ -9,7 +12,7 @@ use std::intrinsics::mir::*;
 pub unsafe fn deref_meta(p: *const *const [i32]) -> usize {
     mir! {
         {
-            RET = PtrMetadata(*p); //~ ERROR: Undefined Behavior: using uninitialized data
+            RET = PtrMetadata(*p); //~ ERROR: /Undefined Behavior: .* but memory is uninitialized/
             Return()
         }
     }
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_len.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_len.stderr
index 00e63b1275f..80b4c8bec0d 100644
--- a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_len.stderr
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_len.stderr
@@ -12,7 +12,7 @@ LL |         (*p.as_mut_ptr().cast::<[*const i32; 2]>())[0] = 4 as *const i32;
    = note: BACKTRACE:
    = note: inside `main` at tests/fail/intrinsics/ptr_metadata_uninit_slice_len.rs:LL:CC
 
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail/intrinsics/ptr_metadata_uninit_slice_len.rs:LL:CC
    |
 LL |             RET = PtrMetadata(*p);
@@ -28,6 +28,9 @@ note: inside `main`
 LL |         let _meta = deref_meta(p.as_ptr().cast());
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
 error: aborting due to 1 previous error; 1 warning emitted
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_thin.rs b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_thin.rs
index e5a51289a8a..3ba29847337 100644
--- a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_thin.rs
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_thin.rs
@@ -1,4 +1,7 @@
 //@compile-flags: -Zmiri-disable-validation
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
+
 #![feature(core_intrinsics, custom_mir)]
 use std::intrinsics::mir::*;
 
@@ -9,7 +12,7 @@ use std::intrinsics::mir::*;
 pub unsafe fn deref_meta(p: *const *const i32) -> () {
     mir! {
         {
-            RET = PtrMetadata(*p); //~ ERROR: Undefined Behavior: using uninitialized data
+            RET = PtrMetadata(*p); //~ ERROR: /Undefined Behavior: .*, but memory is uninitialized/
             Return()
         }
     }
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_thin.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_thin.stderr
index 24066953d79..7a1f3d6ea84 100644
--- a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_thin.stderr
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_thin.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail/intrinsics/ptr_metadata_uninit_thin.rs:LL:CC
    |
 LL |             RET = PtrMetadata(*p);
@@ -14,6 +14,9 @@ note: inside `main`
 LL |         let _meta = deref_meta(p.as_ptr());
    |                     ^^^^^^^^^^^^^^^^^^^^^^
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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/read_from_trivial_switch.rs b/src/tools/miri/tests/fail/read_from_trivial_switch.rs
index d34b1cd5820..2696c42aeae 100644
--- a/src/tools/miri/tests/fail/read_from_trivial_switch.rs
+++ b/src/tools/miri/tests/fail/read_from_trivial_switch.rs
@@ -4,11 +4,14 @@
 //
 // See <https://github.com/rust-lang/miri/issues/4237>.
 
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
+
 use std::mem::MaybeUninit;
 
 fn main() {
     let uninit: MaybeUninit<i32> = MaybeUninit::uninit();
     let bad_ref: &i32 = unsafe { uninit.assume_init_ref() };
     let &(0 | _) = bad_ref;
-    //~^ ERROR: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+    //~^ ERROR: /Undefined Behavior: .*, but memory is uninitialized .* requires initialized memory/
 }
diff --git a/src/tools/miri/tests/fail/read_from_trivial_switch.stderr b/src/tools/miri/tests/fail/read_from_trivial_switch.stderr
index 923d836ee0c..1dcc341b7e6 100644
--- a/src/tools/miri/tests/fail/read_from_trivial_switch.stderr
+++ b/src/tools/miri/tests/fail/read_from_trivial_switch.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail/read_from_trivial_switch.rs:LL:CC
    |
 LL |     let &(0 | _) = bad_ref;
@@ -9,6 +9,9 @@ LL |     let &(0 | _) = bad_ref;
    = note: BACKTRACE:
    = note: inside `main` at tests/fail/read_from_trivial_switch.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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/uninit/padding-enum.rs b/src/tools/miri/tests/fail/uninit/padding-enum.rs
index e1a16bea23c..606fa21016f 100644
--- a/src/tools/miri/tests/fail/uninit/padding-enum.rs
+++ b/src/tools/miri/tests/fail/uninit/padding-enum.rs
@@ -1,3 +1,6 @@
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
+
 use std::mem;
 
 // We have three fields to avoid the ScalarPair optimization.
diff --git a/src/tools/miri/tests/fail/uninit/padding-enum.stderr b/src/tools/miri/tests/fail/uninit/padding-enum.stderr
index a9a5568f4e8..64229ac8817 100644
--- a/src/tools/miri/tests/fail/uninit/padding-enum.stderr
+++ b/src/tools/miri/tests/fail/uninit/padding-enum.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail/uninit/padding-enum.rs:LL:CC
    |
 LL |         let _val = *c.add(padding_offset);
@@ -9,6 +9,9 @@ LL |         let _val = *c.add(padding_offset);
    = note: BACKTRACE:
    = note: inside `main` at tests/fail/uninit/padding-enum.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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/uninit/padding-pair.rs b/src/tools/miri/tests/fail/uninit/padding-pair.rs
index c8c00b3c65a..70ae48ff77d 100644
--- a/src/tools/miri/tests/fail/uninit/padding-pair.rs
+++ b/src/tools/miri/tests/fail/uninit/padding-pair.rs
@@ -1,3 +1,6 @@
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
+
 #![feature(core_intrinsics)]
 
 use std::mem::{self, MaybeUninit};
diff --git a/src/tools/miri/tests/fail/uninit/padding-pair.stderr b/src/tools/miri/tests/fail/uninit/padding-pair.stderr
index d281a351d41..2e7a577f204 100644
--- a/src/tools/miri/tests/fail/uninit/padding-pair.stderr
+++ b/src/tools/miri/tests/fail/uninit/padding-pair.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail/uninit/padding-pair.rs:LL:CC
    |
 LL |     let v = unsafe { *z.offset(first_undef) };
@@ -9,6 +9,9 @@ LL |     let v = unsafe { *z.offset(first_undef) };
    = note: BACKTRACE:
    = note: inside `main` at tests/fail/uninit/padding-pair.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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/uninit/padding-struct.stderr b/src/tools/miri/tests/fail/uninit/padding-struct.stderr
index 3298f6a4510..05d754625d3 100644
--- a/src/tools/miri/tests/fail/uninit/padding-struct.stderr
+++ b/src/tools/miri/tests/fail/uninit/padding-struct.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0x1..0x2], but memory is uninitialized at [0x1..0x2], and this operation requires initialized memory
   --> tests/fail/uninit/padding-struct.rs:LL:CC
    |
 LL |         let _val = *c.add(1);
@@ -9,6 +9,11 @@ LL |         let _val = *c.add(1);
    = note: BACKTRACE:
    = note: inside `main` at tests/fail/uninit/padding-struct.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0x1..0x2], in this allocation:
+ALLOC (stack variable, size: 4, align: 2) {
+    00 __ 00 00                                     │ .░..
+}
+
 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/uninit/padding-wide-ptr.rs b/src/tools/miri/tests/fail/uninit/padding-wide-ptr.rs
index 4e363dbf81e..549785e0223 100644
--- a/src/tools/miri/tests/fail/uninit/padding-wide-ptr.rs
+++ b/src/tools/miri/tests/fail/uninit/padding-wide-ptr.rs
@@ -1,3 +1,6 @@
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
+
 use std::mem;
 
 // If this is `None`, the metadata becomes padding.
diff --git a/src/tools/miri/tests/fail/uninit/padding-wide-ptr.stderr b/src/tools/miri/tests/fail/uninit/padding-wide-ptr.stderr
index d92d05ae631..ce11320ca1b 100644
--- a/src/tools/miri/tests/fail/uninit/padding-wide-ptr.stderr
+++ b/src/tools/miri/tests/fail/uninit/padding-wide-ptr.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail/uninit/padding-wide-ptr.rs:LL:CC
    |
 LL |         let _val = *c.add(mem::size_of::<*const u8>());
@@ -9,6 +9,9 @@ LL |         let _val = *c.add(mem::size_of::<*const u8>());
    = note: BACKTRACE:
    = note: inside `main` at tests/fail/uninit/padding-wide-ptr.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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/uninit/transmute-pair-uninit.rs b/src/tools/miri/tests/fail/uninit/transmute-pair-uninit.rs
index 0ba5520a544..c1d284c7057 100644
--- a/src/tools/miri/tests/fail/uninit/transmute-pair-uninit.rs
+++ b/src/tools/miri/tests/fail/uninit/transmute-pair-uninit.rs
@@ -1,3 +1,6 @@
+//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
+//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
+
 #![feature(core_intrinsics)]
 
 use std::mem::{self, MaybeUninit};
diff --git a/src/tools/miri/tests/fail/uninit/transmute-pair-uninit.stderr b/src/tools/miri/tests/fail/uninit/transmute-pair-uninit.stderr
index 0ae0ce5de9c..eb049dd41ec 100644
--- a/src/tools/miri/tests/fail/uninit/transmute-pair-uninit.stderr
+++ b/src/tools/miri/tests/fail/uninit/transmute-pair-uninit.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0xX..0xY], but memory is uninitialized at [0xX..0xY], and this operation requires initialized memory
   --> tests/fail/uninit/transmute-pair-uninit.rs:LL:CC
    |
 LL |     let v = unsafe { *z.offset(first_undef) };
@@ -9,6 +9,9 @@ LL |     let v = unsafe { *z.offset(first_undef) };
    = note: BACKTRACE:
    = note: inside `main` at tests/fail/uninit/transmute-pair-uninit.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
+ALLOC DUMP
+
 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/uninit/uninit_byte_read.stderr b/src/tools/miri/tests/fail/uninit/uninit_byte_read.stderr
index d2a5a2d3831..5a5aa12987c 100644
--- a/src/tools/miri/tests/fail/uninit/uninit_byte_read.stderr
+++ b/src/tools/miri/tests/fail/uninit/uninit_byte_read.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0x5..0x6], but memory is uninitialized at [0x5..0x6], and this operation requires initialized memory
   --> tests/fail/uninit/uninit_byte_read.rs:LL:CC
    |
 LL |     let undef = unsafe { *v.as_ptr().add(5) };
@@ -9,6 +9,11 @@ LL |     let undef = unsafe { *v.as_ptr().add(5) };
    = note: BACKTRACE:
    = note: inside `main` at tests/fail/uninit/uninit_byte_read.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0x5..0x6], in this allocation:
+ALLOC (Rust heap, size: 10, align: 1) {
+    __ __ __ __ __ __ __ __ __ __                   │ ░░░░░░░░░░
+}
+
 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/validity/invalid_int_op.stderr b/src/tools/miri/tests/fail/validity/invalid_int_op.stderr
index 6e24cadfc20..0b1915621b2 100644
--- a/src/tools/miri/tests/fail/validity/invalid_int_op.stderr
+++ b/src/tools/miri/tests/fail/validity/invalid_int_op.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0x0..0x4], but memory is uninitialized at [0x0..0x4], and this operation requires initialized memory
   --> tests/fail/validity/invalid_int_op.rs:LL:CC
    |
 LL |     let i = unsafe { std::mem::MaybeUninit::<i32>::uninit().assume_init() };
@@ -9,6 +9,11 @@ LL |     let i = unsafe { std::mem::MaybeUninit::<i32>::uninit().assume_init() }
    = note: BACKTRACE:
    = note: inside `main` at tests/fail/validity/invalid_int_op.rs:LL:CC
 
+Uninitialized memory occurred at ALLOC[0x0..0x4], in this allocation:
+ALLOC (stack variable, size: 4, align: 4) {
+    __ __ __ __                                     │ ░░░░
+}
+
 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/native-lib/fail/tracing/partial_init.rs b/src/tools/miri/tests/native-lib/fail/tracing/partial_init.rs
index e267f82e215..7ab160773ff 100644
--- a/src/tools/miri/tests/native-lib/fail/tracing/partial_init.rs
+++ b/src/tools/miri/tests/native-lib/fail/tracing/partial_init.rs
@@ -20,6 +20,6 @@ fn partial_init() {
         assert!(*slice_ptr == 0);
         assert!(*slice_ptr.offset(1) == 0);
         // Reading the third is UB!
-        let _val = *slice_ptr.offset(2); //~ ERROR: Undefined Behavior: using uninitialized data
+        let _val = *slice_ptr.offset(2); //~ ERROR: /Undefined Behavior: reading memory.*, but memory is uninitialized/
     }
 }
diff --git a/src/tools/miri/tests/native-lib/fail/tracing/partial_init.stderr b/src/tools/miri/tests/native-lib/fail/tracing/partial_init.stderr
index 84fd913b5e5..74a599ede5c 100644
--- a/src/tools/miri/tests/native-lib/fail/tracing/partial_init.stderr
+++ b/src/tools/miri/tests/native-lib/fail/tracing/partial_init.stderr
@@ -17,7 +17,7 @@ note: inside `main`
 LL |     partial_init();
    |     ^^^^^^^^^^^^^^
 
-error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+error: Undefined Behavior: reading memory at ALLOC[0x2..0x3], but memory is uninitialized at [0x2..0x3], and this operation requires initialized memory
   --> tests/native-lib/fail/tracing/partial_init.rs:LL:CC
    |
 LL |         let _val = *slice_ptr.offset(2);
@@ -33,6 +33,11 @@ note: inside `main`
 LL |     partial_init();
    |     ^^^^^^^^^^^^^^
 
+Uninitialized memory occurred at ALLOC[0x2..0x3], in this allocation:
+ALLOC (stack variable, size: 3, align: 1) {
+    ╾00[wildcard] (1 ptr byte)╼ ╾00[wildcard] (1 ptr byte)╼ __                                        │ ━━░
+}
+
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
 error: aborting due to 1 previous error; 1 warning emitted