2 use std::num::NonZeroU64;
6 use rustc_span::{source_map::DUMMY_SP, SpanData, Symbol};
7 use rustc_target::abi::{Align, Size};
9 use crate::stacked_borrows::{diagnostics::TagHistory, AccessKind};
12 /// Details of premature program termination.
13 pub enum TerminationInfo {
16 UnsupportedInIsolation(String),
20 history: Option<TagHistory>,
22 Int2PtrWithStrictProvenance,
24 MultipleSymbolDefinitions {
37 impl fmt::Display for TerminationInfo {
38 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
39 use TerminationInfo::*;
41 Exit(code) => write!(f, "the evaluated program completed with exit code {code}"),
42 Abort(msg) => write!(f, "{msg}"),
43 UnsupportedInIsolation(msg) => write!(f, "{msg}"),
44 Int2PtrWithStrictProvenance =>
47 "integer-to-pointer casts and `ptr::from_exposed_addr` are not supported with `-Zmiri-strict-provenance`"
49 StackedBorrowsUb { msg, .. } => write!(f, "{msg}"),
50 Deadlock => write!(f, "the evaluated program deadlocked"),
51 MultipleSymbolDefinitions { link_name, .. } =>
52 write!(f, "multiple definitions of symbol `{link_name}`"),
53 SymbolShimClashing { link_name, .. } =>
54 write!(f, "found `{link_name}` symbol definition that clashes with a built-in shim",),
59 impl MachineStopType for TerminationInfo {}
61 /// Miri specific diagnostics
62 pub enum NonHaltingDiagnostic {
63 /// (new_tag, new_kind, (alloc_id, base_offset, orig_tag))
65 /// new_kind is `None` for base tags.
66 CreatedPointerTag(NonZeroU64, Option<String>, Option<(AllocId, AllocRange, ProvenanceExtra)>),
67 /// This `Item` was popped from the borrow stack, either due to an access with the given tag or
68 /// a deallocation when the second argument is `None`.
69 PoppedPointerTag(Item, Option<(ProvenanceExtra, AccessKind)>),
70 CreatedCallId(CallId),
71 CreatedAlloc(AllocId, Size, Align, MemoryKind<MiriMemoryKind>),
73 RejectedIsolatedOp(String),
75 block_count: u64, // how many basic blocks have been run so far
80 WeakMemoryOutdatedLoad,
83 /// Level of Miri specific diagnostics
90 /// Attempts to prune a stacktrace to omit the Rust runtime, and returns a bool indicating if any
91 /// frames were pruned. If the stacktrace does not have any local frames, we conclude that it must
92 /// be pointing to a problem in the Rust runtime itself, and do not prune it at all.
93 fn prune_stacktrace<'tcx>(
94 mut stacktrace: Vec<FrameInfo<'tcx>>,
95 machine: &MiriMachine<'_, 'tcx>,
96 ) -> (Vec<FrameInfo<'tcx>>, bool) {
97 match machine.backtrace_style {
98 BacktraceStyle::Off => {
99 // Remove all frames marked with `caller_location` -- that attribute indicates we
100 // usually want to point at the caller, not them.
101 stacktrace.retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
102 // Retain one frame so that we can print a span for the error itself
103 stacktrace.truncate(1);
106 BacktraceStyle::Short => {
107 let original_len = stacktrace.len();
108 // Only prune frames if there is at least one local frame. This check ensures that if
109 // we get a backtrace that never makes it to the user code because it has detected a
110 // bug in the Rust runtime, we don't prune away every frame.
111 let has_local_frame = stacktrace.iter().any(|frame| machine.is_local(frame));
113 // Remove all frames marked with `caller_location` -- that attribute indicates we
114 // usually want to point at the caller, not them.
116 .retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
118 // This is part of the logic that `std` uses to select the relevant part of a
119 // backtrace. But here, we only look for __rust_begin_short_backtrace, not
120 // __rust_end_short_backtrace because the end symbol comes from a call to the default
122 stacktrace = stacktrace
124 .take_while(|frame| {
125 let def_id = frame.instance.def_id();
126 let path = machine.tcx.def_path_str(def_id);
127 !path.contains("__rust_begin_short_backtrace")
129 .collect::<Vec<_>>();
131 // After we prune frames from the bottom, there are a few left that are part of the
132 // Rust runtime. So we remove frames until we get to a local symbol, which should be
134 // This len check ensures that we don't somehow remove every frame, as doing so breaks
135 // the primary error message.
136 while stacktrace.len() > 1
137 && stacktrace.last().map_or(false, |frame| !machine.is_local(frame))
142 let was_pruned = stacktrace.len() != original_len;
143 (stacktrace, was_pruned)
145 BacktraceStyle::Full => (stacktrace, false),
149 /// Emit a custom diagnostic without going through the miri-engine machinery.
151 /// Returns `Some` if this was regular program termination with a given exit code, `None` otherwise.
152 pub fn report_error<'tcx, 'mir>(
153 ecx: &InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>,
154 e: InterpErrorInfo<'tcx>,
158 let mut msg = vec![];
160 let (title, helps) = if let MachineStop(info) = e.kind() {
161 let info = info.downcast_ref::<TerminationInfo>().expect("invalid MachineStop payload");
162 use TerminationInfo::*;
163 let title = match info {
164 Exit(code) => return Some(*code),
165 Abort(_) => Some("abnormal termination"),
166 UnsupportedInIsolation(_) | Int2PtrWithStrictProvenance =>
167 Some("unsupported operation"),
168 StackedBorrowsUb { .. } => Some("Undefined Behavior"),
169 Deadlock => Some("deadlock"),
170 MultipleSymbolDefinitions { .. } | SymbolShimClashing { .. } => None,
173 let helps = match info {
174 UnsupportedInIsolation(_) =>
176 (None, format!("pass the flag `-Zmiri-disable-isolation` to disable isolation;")),
177 (None, format!("or pass `-Zmiri-isolation-error=warn` to configure Miri to return an error code from isolated operations (if supported for that operation) and continue with a warning")),
179 StackedBorrowsUb { help, history, .. } => {
180 let url = "https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md";
181 msg.extend(help.clone());
182 let mut helps = vec![
183 (None, format!("this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental")),
184 (None, format!("see {url} for further information")),
186 if let Some(TagHistory {created, invalidated, protected}) = history.clone() {
187 helps.push((Some(created.1), created.0));
188 if let Some((msg, span)) = invalidated {
189 helps.push((Some(span), msg));
191 if let Some((protector_msg, protector_span)) = protected {
192 helps.push((Some(protector_span), protector_msg));
197 MultipleSymbolDefinitions { first, first_crate, second, second_crate, .. } =>
199 (Some(*first), format!("it's first defined here, in crate `{first_crate}`")),
200 (Some(*second), format!("then it's defined here again, in crate `{second_crate}`")),
202 SymbolShimClashing { link_name, span } =>
203 vec![(Some(*span), format!("the `{link_name}` symbol is defined here"))],
204 Int2PtrWithStrictProvenance =>
205 vec![(None, format!("use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead"))],
211 let title = match e.kind() {
212 UndefinedBehavior(_) =>
213 "Undefined Behavior",
214 ResourceExhaustion(_) =>
215 "resource exhaustion",
217 // We list only the ones that can actually happen.
218 UnsupportedOpInfo::Unsupported(_)
220 "unsupported operation",
222 // We list only the ones that can actually happen.
223 InvalidProgramInfo::AlreadyReported(_) |
224 InvalidProgramInfo::Layout(..)
226 "post-monomorphization error",
228 bug!("This error should be impossible in Miri: {kind:?}"),
231 let helps = match e.kind() {
233 vec![(None, format!("this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support"))],
234 UndefinedBehavior(UndefinedBehaviorInfo::AlignmentCheckFailed { .. })
235 if ecx.machine.check_alignment == AlignmentCheck::Symbolic
238 (None, format!("this usually indicates that your program performed an invalid operation and caused Undefined Behavior")),
239 (None, format!("but due to `-Zmiri-symbolic-alignment-check`, alignment errors can also be false positives")),
241 UndefinedBehavior(_) =>
243 (None, format!("this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior")),
244 (None, format!("see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information")),
247 InvalidProgramInfo::AlreadyReported(rustc_errors::ErrorGuaranteed { .. })
249 // This got already reported. No point in reporting it again.
258 let stacktrace = ecx.generate_stacktrace();
259 let (stacktrace, was_pruned) = prune_stacktrace(stacktrace, &ecx.machine);
261 msg.insert(0, e.to_string());
264 &if let Some(title) = title { format!("{title}: {}", msg[0]) } else { msg[0].clone() },
272 // Include a note like `std` does when we omit frames from a backtrace
274 ecx.tcx.sess.diagnostic().note_without_error(
275 "some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace",
279 // Debug-dump all locals.
280 for (i, frame) in ecx.active_thread_stack().iter().enumerate() {
281 trace!("-------------------");
282 trace!("Frame {}", i);
283 trace!(" return: {:?}", *frame.return_place);
284 for (i, local) in frame.locals.iter().enumerate() {
285 trace!(" local {}: {:?}", i, local.value);
289 // Extra output to help debug specific issues.
291 UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(Some((alloc_id, access)))) => {
293 "Uninitialized memory occurred at {alloc_id:?}{range:?}, in this allocation:",
294 range = access.uninit,
296 eprintln!("{:?}", ecx.dump_alloc(*alloc_id));
304 /// Report an error or note (depending on the `error` argument) with the given stacktrace.
305 /// Also emits a full stacktrace of the interpreter stack.
306 /// We want to present a multi-line span message for some errors. Diagnostics do not support this
307 /// directly, so we pass the lines as a `Vec<String>` and display each line after the first with an
308 /// additional `span_label` or `note` call.
310 diag_level: DiagLevel,
312 span_msg: Vec<String>,
313 notes: Vec<(Option<SpanData>, String)>,
314 helps: Vec<(Option<SpanData>, String)>,
315 stacktrace: &[FrameInfo<'tcx>],
316 machine: &MiriMachine<'_, 'tcx>,
318 let span = stacktrace.first().map_or(DUMMY_SP, |fi| fi.span);
319 let sess = machine.tcx.sess;
320 let mut err = match diag_level {
321 DiagLevel::Error => sess.struct_span_err(span, title).forget_guarantee(),
322 DiagLevel::Warning => sess.struct_span_warn(span, title),
323 DiagLevel::Note => sess.diagnostic().span_note_diag(span, title),
326 // Show main message.
327 if span != DUMMY_SP {
328 for line in span_msg {
329 err.span_label(span, line);
332 // Make sure we show the message even when it is a dummy span.
333 for line in span_msg {
336 err.note("(no span available)");
339 // Show note and help messages.
340 for (span_data, note) in ¬es {
341 if let Some(span_data) = span_data {
342 err.span_note(span_data.span(), note);
347 for (span_data, help) in &helps {
348 if let Some(span_data) = span_data {
349 err.span_help(span_data.span(), help);
354 if notes.len() + helps.len() > 0 {
355 // Add visual separator before backtrace.
356 err.note("BACKTRACE:");
359 for (idx, frame_info) in stacktrace.iter().enumerate() {
360 let is_local = machine.is_local(frame_info);
361 // No span for non-local frames and the first frame (which is the error site).
362 if is_local && idx > 0 {
363 err.span_note(frame_info.span, &frame_info.to_string());
365 err.note(&frame_info.to_string());
372 impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
373 pub fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
374 use NonHaltingDiagnostic::*;
377 MiriInterpCx::generate_stacktrace_from_stack(self.threads.active_thread_stack());
378 let (stacktrace, _was_pruned) = prune_stacktrace(stacktrace, self);
380 let (title, diag_level) = match &e {
381 RejectedIsolatedOp(_) => ("operation rejected by isolation", DiagLevel::Warning),
382 Int2Ptr { .. } => ("integer-to-pointer cast", DiagLevel::Warning),
383 CreatedPointerTag(..)
384 | PoppedPointerTag(..)
388 | ProgressReport { .. }
389 | WeakMemoryOutdatedLoad => ("tracking was triggered", DiagLevel::Note),
393 CreatedPointerTag(tag, None, _) => format!("created base tag {tag:?}"),
394 CreatedPointerTag(tag, Some(kind), None) => format!("created {tag:?} for {kind}"),
395 CreatedPointerTag(tag, Some(kind), Some((alloc_id, range, orig_tag))) =>
397 "created tag {tag:?} for {kind} at {alloc_id:?}{range:?} derived from {orig_tag:?}"
399 PoppedPointerTag(item, tag) =>
401 None => format!("popped tracked tag for item {item:?} due to deallocation",),
402 Some((tag, access)) => {
404 "popped tracked tag for item {item:?} due to {access:?} access for {tag:?}",
408 CreatedCallId(id) => format!("function call with id {id}"),
409 CreatedAlloc(AllocId(id), size, align, kind) =>
411 "created {kind} allocation of {size} bytes (alignment {align} bytes) with id {id}",
413 align = align.bytes(),
415 FreedAlloc(AllocId(id)) => format!("freed allocation with id {id}"),
416 RejectedIsolatedOp(ref op) =>
417 format!("{op} was made to return an error due to isolation"),
418 ProgressReport { .. } =>
419 format!("progress report: current operation being executed is here"),
420 Int2Ptr { .. } => format!("integer-to-pointer cast"),
421 WeakMemoryOutdatedLoad =>
422 format!("weak memory emulation: outdated value returned from load"),
425 let notes = match &e {
426 ProgressReport { block_count } => {
427 // It is important that each progress report is slightly different, since
428 // identical diagnostics are being deduplicated.
429 vec![(None, format!("so far, {block_count} basic blocks have been executed"))]
434 let helps = match &e {
435 Int2Ptr { details: true } =>
440 "This program is using integer-to-pointer casts or (equivalently) `ptr::from_exposed_addr`,"
445 format!("which means that Miri might miss pointer bugs in this program."),
450 "See https://doc.rust-lang.org/nightly/std/ptr/fn.from_exposed_addr.html for more details on that operation."
456 "To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead."
462 "You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `from_exposed_addr` semantics."
468 "Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning."
475 report_msg(diag_level, title, vec![msg], notes, helps, &stacktrace, self);
479 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
480 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
481 fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
482 let this = self.eval_context_ref();
483 this.machine.emit_diagnostic(e);
486 /// We had a panic in Miri itself, try to print something useful.
487 fn handle_ice(&self) {
490 "Miri caused an ICE during evaluation. Here's the interpreter backtrace at the time of the panic:"
492 let this = self.eval_context_ref();
493 let stacktrace = this.generate_stacktrace();
496 "the place in the program where the ICE was triggered",