Show the offset, length and memory of uninit read errors

compiler/rustc_const_eval/src/const_eval/error.rs

@@ -2,16 +2,16 @@ use std::mem;
 
 use rustc_errors::{Diag, DiagArgName, DiagArgValue, DiagMessage, IntoDiagArg};
 use rustc_middle::mir::AssertKind;
-use rustc_middle::mir::interpret::{Provenance, ReportedErrorInfo};
+use rustc_middle::mir::interpret::{Provenance, ReportedErrorInfo, UndefinedBehaviorInfo};
 use rustc_middle::query::TyCtxtAt;
+use rustc_middle::ty::ConstInt;
 use rustc_middle::ty::layout::LayoutError;
-use rustc_middle::ty::{ConstInt, TyCtxt};
 use rustc_span::{Span, Symbol};
 
 use super::CompileTimeMachine;
 use crate::errors::{self, FrameNote, ReportErrorExt};
 use crate::interpret::{
-    ErrorHandled, Frame, InterpErrorInfo, InterpErrorKind, MachineStopType, err_inval,
+    ErrorHandled, Frame, InterpCx, InterpErrorInfo, InterpErrorKind, MachineStopType, err_inval,
     err_machine_stop,
 };
 
@@ -135,7 +135,7 @@ pub fn get_span_and_frames<'tcx>(
 /// You can use it to add a stacktrace of current execution according to
 /// `get_span_and_frames` or just give context on where the const eval error happened.
 pub(super) fn report<'tcx, C, F>(
-    tcx: TyCtxt<'tcx>,
+    ecx: &InterpCx<'tcx, CompileTimeMachine<'tcx>>,
     error: InterpErrorKind<'tcx>,
     span: Span,
     get_span_and_frames: C,
@@ -145,6 +145,7 @@ where
     C: FnOnce() -> (Span, Vec<FrameNote>),
     F: FnOnce(&mut Diag<'_>, Span, Vec<FrameNote>),
 {
+    let tcx = ecx.tcx.tcx;
     // Special handling for certain errors
     match error {
         // Don't emit a new diagnostic for these errors, they are already reported elsewhere or
@@ -170,9 +171,24 @@ where
                 InterpErrorKind::ResourceExhaustion(_) | InterpErrorKind::InvalidProgram(_)
             );
 
+            if let InterpErrorKind::UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(
+                Some((alloc_id, _access)),
+            )) = error
+            {
+                let bytes = ecx.print_alloc_bytes_for_diagnostics(alloc_id);
+                let info = ecx.get_alloc_info(alloc_id);
+                let raw_bytes = errors::RawBytesNote {
+                    size: info.size.bytes(),
+                    align: info.align.bytes(),
+                    bytes,
+                };
+                err.subdiagnostic(raw_bytes);
+            }
+
             error.add_args(&mut err);
 
             mk(&mut err, span, frames);
+
             let g = err.emit();
             let reported = if allowed_in_infallible {
                 ReportedErrorInfo::allowed_in_infallible(g)

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -293,7 +293,12 @@ pub fn eval_to_const_value_raw_provider<'tcx>(
 
                 // FIXME(oli-obk): why don't we have any tests for this code path?
                 super::report(
-                    tcx,
+                    &InterpCx::new(
+                        tcx,
+                        tcx.def_span(def_id),
+                        key.typing_env,
+                        CompileTimeMachine::new(CanAccessMutGlobal::Yes, CheckAlignment::No),
+                    ),
                     error.into_kind(),
                     span,
                     || (span, vec![]),
@@ -433,7 +438,7 @@ fn report_eval_error<'tcx>(
     let instance = with_no_trimmed_paths!(cid.instance.to_string());
 
     super::report(
-        *ecx.tcx,
+        ecx,
         error,
         DUMMY_SP,
         || super::get_span_and_frames(ecx.tcx, ecx.stack()),
@@ -473,7 +478,7 @@ fn report_validation_error<'tcx>(
         errors::RawBytesNote { size: info.size.bytes(), align: info.align.bytes(), bytes };
 
     crate::const_eval::report(
-        *ecx.tcx,
+        ecx,
         error,
         DUMMY_SP,
         || crate::const_eval::get_span_and_frames(ecx.tcx, ecx.stack()),

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -7,7 +7,7 @@ use either::{Either, Left, Right};
 use rustc_abi as abi;
 use rustc_abi::{BackendRepr, HasDataLayout, Size};
 use rustc_hir::def::Namespace;
-use rustc_middle::mir::interpret::ScalarSizeMismatch;
+use rustc_middle::mir::interpret::{BadBytesAccess, ScalarSizeMismatch};
 use rustc_middle::ty::layout::{HasTyCtxt, HasTypingEnv, LayoutOf, TyAndLayout};
 use rustc_middle::ty::print::{FmtPrinter, PrettyPrinter};
 use rustc_middle::ty::{ConstInt, ScalarInt, Ty, TyCtxt};
@@ -663,7 +663,15 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         }
         let imm = self.read_immediate_raw(op)?.right().unwrap();
         if matches!(*imm, Immediate::Uninit) {
-            throw_ub!(InvalidUninitBytes(None));
+            throw_ub!(InvalidUninitBytes(match op.to_op(self)?.as_mplace_or_imm() {
+                Left(mplace) => mplace.ptr().provenance.and_then(|prov| {
+                    let start = mplace.ptr().into_parts().1;
+                    let size = op.layout().size;
+                    let range = alloc_range(start, size);
+                    Some((prov.get_alloc_id()?, BadBytesAccess { access: range, bad: range }))
+                }),
+                Right(_) => None,
+            }))
         }
         interp_ok(imm)
     }

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -396,7 +396,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> {
         interp_ok(try_validation!(
             self.ecx.read_immediate(val),
             self.path,
-            Ub(InvalidUninitBytes(None)) =>
+            Ub(InvalidUninitBytes(_)) =>
                 Uninit { expected },
             // The `Unsup` cases can only occur during CTFE
             Unsup(ReadPointerAsInt(_)) =>

compiler/rustc_middle/src/mir/interpret/allocation.rs

@@ -700,8 +700,11 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
         read_provenance: bool,
     ) -> AllocResult<Scalar<Prov>> {
         // First and foremost, if anything is uninit, bail.
-        if self.init_mask.is_range_initialized(range).is_err() {
-            return Err(AllocError::InvalidUninitBytes(None));
+        if let Err(bad) = self.init_mask.is_range_initialized(range) {
+            return Err(AllocError::InvalidUninitBytes(Some(BadBytesAccess {
+                access: range,
+                bad,
+            })));
         }
 
         // Get the integer part of the result. We HAVE TO check provenance before returning this!

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.rs

@@ -1,4 +1,8 @@
 //@ignore-target: windows # No pthreads on Windows
+//@ normalize-stderr-test: ".*│.*\n" -> ""
+//@ normalize-stderr-test: "size: [0-9]+" -> "size: SIZE"
+//@ normalize-stderr-test: "align: [0-9]+" -> "align: ALIGN"
+//@ 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 +19,6 @@ 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: .* but memory is uninitialized/
     }
 }

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 +9,10 @@ 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 (stack variable, size: SIZE, align: ALIGN) {
+}
+
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
 error: aborting due to 1 previous error

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.rs

@@ -1,5 +1,9 @@
 //@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" -> ""
+//@ normalize-stderr-test: "size: [0-9]+" -> "size: SIZE"
+//@ normalize-stderr-test: "align: [0-9]+" -> "align: ALIGN"
+//@ 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 +17,6 @@ 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: .* but memory is uninitialized/
     }
 }

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 +9,10 @@ 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 (stack variable, size: SIZE, align: ALIGN) {
+}
+
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
 error: aborting due to 1 previous error

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.rs

@@ -1,4 +1,8 @@
 //@ignore-target: windows # No pthreads on Windows
+//@ normalize-stderr-test: ".*│.*\n" -> ""
+//@ normalize-stderr-test: "size: [0-9]+" -> "size: SIZE"
+//@ normalize-stderr-test: "align: [0-9]+" -> "align: ALIGN"
+//@ 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 +20,6 @@ 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: .* but memory is uninitialized/
     }
 }

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 +9,10 @@ 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 (stack variable, size: SIZE, align: ALIGN) {
+}
+
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
 error: aborting due to 1 previous error

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.rs

@@ -1,4 +1,8 @@
 //@ignore-target: windows # No pthreads on Windows
+//@ normalize-stderr-test: ".*│.*\n" -> ""
+//@ normalize-stderr-test: "size: [0-9]+" -> "size: SIZE"
+//@ normalize-stderr-test: "align: [0-9]+" -> "align: ALIGN"
+//@ 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 +16,6 @@ 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: .* but memory is uninitialized/
     }
 }

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 +9,10 @@ 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 (stack variable, size: SIZE, align: ALIGN) {
+}
+
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
 error: aborting due to 1 previous error

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.rs

@@ -1,4 +1,8 @@
 //@ignore-target: windows # No pthreads on Windows
+//@ normalize-stderr-test: ".*│.*\n" -> ""
+//@ normalize-stderr-test: "size: [0-9]+" -> "size: SIZE"
+//@ normalize-stderr-test: "align: [0-9]+" -> "align: ALIGN"
+//@ 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 +13,6 @@ 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: .* but memory is uninitialized/
     }
 }

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 +9,10 @@ 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 (stack variable, size: SIZE, align: ALIGN) {
+}
+
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
 error: aborting due to 1 previous error

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

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

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

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