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 {
19 UnsupportedInIsolation(String),
23 history: Option<TagHistory>,
25 Int2PtrWithStrictProvenance,
27 MultipleSymbolDefinitions {
40 impl fmt::Display for TerminationInfo {
41 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
42 use TerminationInfo::*;
44 Exit { code, .. } => write!(f, "the evaluated program completed with exit code {code}"),
45 Abort(msg) => write!(f, "{msg}"),
46 UnsupportedInIsolation(msg) => write!(f, "{msg}"),
47 Int2PtrWithStrictProvenance =>
50 "integer-to-pointer casts and `ptr::from_exposed_addr` are not supported with `-Zmiri-strict-provenance`"
52 StackedBorrowsUb { msg, .. } => write!(f, "{msg}"),
53 Deadlock => write!(f, "the evaluated program deadlocked"),
54 MultipleSymbolDefinitions { link_name, .. } =>
55 write!(f, "multiple definitions of symbol `{link_name}`"),
56 SymbolShimClashing { link_name, .. } =>
57 write!(f, "found `{link_name}` symbol definition that clashes with a built-in shim",),
62 impl MachineStopType for TerminationInfo {}
64 /// Miri specific diagnostics
65 pub enum NonHaltingDiagnostic {
66 /// (new_tag, new_kind, (alloc_id, base_offset, orig_tag))
68 /// new_kind is `None` for base tags.
69 CreatedPointerTag(NonZeroU64, Option<String>, Option<(AllocId, AllocRange, ProvenanceExtra)>),
70 /// This `Item` was popped from the borrow stack, either due to an access with the given tag or
71 /// a deallocation when the second argument is `None`.
72 PoppedPointerTag(Item, Option<(ProvenanceExtra, AccessKind)>),
73 CreatedCallId(CallId),
74 CreatedAlloc(AllocId, Size, Align, MemoryKind<MiriMemoryKind>),
76 RejectedIsolatedOp(String),
78 block_count: u64, // how many basic blocks have been run so far
83 WeakMemoryOutdatedLoad,
86 /// Level of Miri specific diagnostics
93 /// Attempts to prune a stacktrace to omit the Rust runtime, and returns a bool indicating if any
94 /// frames were pruned. If the stacktrace does not have any local frames, we conclude that it must
95 /// be pointing to a problem in the Rust runtime itself, and do not prune it at all.
96 fn prune_stacktrace<'tcx>(
97 mut stacktrace: Vec<FrameInfo<'tcx>>,
98 machine: &MiriMachine<'_, 'tcx>,
99 ) -> (Vec<FrameInfo<'tcx>>, bool) {
100 match machine.backtrace_style {
101 BacktraceStyle::Off => {
102 // Remove all frames marked with `caller_location` -- that attribute indicates we
103 // usually want to point at the caller, not them.
104 stacktrace.retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
105 // Retain one frame so that we can print a span for the error itself
106 stacktrace.truncate(1);
109 BacktraceStyle::Short => {
110 let original_len = stacktrace.len();
111 // Only prune frames if there is at least one local frame. This check ensures that if
112 // we get a backtrace that never makes it to the user code because it has detected a
113 // bug in the Rust runtime, we don't prune away every frame.
114 let has_local_frame = stacktrace.iter().any(|frame| machine.is_local(frame));
116 // Remove all frames marked with `caller_location` -- that attribute indicates we
117 // usually want to point at the caller, not them.
119 .retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
121 // This is part of the logic that `std` uses to select the relevant part of a
122 // backtrace. But here, we only look for __rust_begin_short_backtrace, not
123 // __rust_end_short_backtrace because the end symbol comes from a call to the default
125 stacktrace = stacktrace
127 .take_while(|frame| {
128 let def_id = frame.instance.def_id();
129 let path = machine.tcx.def_path_str(def_id);
130 !path.contains("__rust_begin_short_backtrace")
132 .collect::<Vec<_>>();
134 // After we prune frames from the bottom, there are a few left that are part of the
135 // Rust runtime. So we remove frames until we get to a local symbol, which should be
137 // This len check ensures that we don't somehow remove every frame, as doing so breaks
138 // the primary error message.
139 while stacktrace.len() > 1
140 && stacktrace.last().map_or(false, |frame| !machine.is_local(frame))
145 let was_pruned = stacktrace.len() != original_len;
146 (stacktrace, was_pruned)
148 BacktraceStyle::Full => (stacktrace, false),
152 /// Emit a custom diagnostic without going through the miri-engine machinery.
154 /// Returns `Some` if this was regular program termination with a given exit code and a `bool` indicating whether a leak check should happen; `None` otherwise.
155 pub fn report_error<'tcx, 'mir>(
156 ecx: &InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>,
157 e: InterpErrorInfo<'tcx>,
158 ) -> Option<(i64, bool)> {
161 let mut msg = vec![];
163 let (title, helps) = if let MachineStop(info) = e.kind() {
164 let info = info.downcast_ref::<TerminationInfo>().expect("invalid MachineStop payload");
165 use TerminationInfo::*;
166 let title = match info {
167 Exit { code, leak_check } => return Some((*code, *leak_check)),
168 Abort(_) => Some("abnormal termination"),
169 UnsupportedInIsolation(_) | Int2PtrWithStrictProvenance =>
170 Some("unsupported operation"),
171 StackedBorrowsUb { .. } => Some("Undefined Behavior"),
172 Deadlock => Some("deadlock"),
173 MultipleSymbolDefinitions { .. } | SymbolShimClashing { .. } => None,
176 let helps = match info {
177 UnsupportedInIsolation(_) =>
179 (None, format!("pass the flag `-Zmiri-disable-isolation` to disable isolation;")),
180 (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")),
182 StackedBorrowsUb { help, history, .. } => {
183 let url = "https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md";
184 msg.extend(help.clone());
185 let mut helps = vec![
186 (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")),
187 (None, format!("see {url} for further information")),
189 if let Some(TagHistory {created, invalidated, protected}) = history.clone() {
190 helps.push((Some(created.1), created.0));
191 if let Some((msg, span)) = invalidated {
192 helps.push((Some(span), msg));
194 if let Some((protector_msg, protector_span)) = protected {
195 helps.push((Some(protector_span), protector_msg));
200 MultipleSymbolDefinitions { first, first_crate, second, second_crate, .. } =>
202 (Some(*first), format!("it's first defined here, in crate `{first_crate}`")),
203 (Some(*second), format!("then it's defined here again, in crate `{second_crate}`")),
205 SymbolShimClashing { link_name, span } =>
206 vec![(Some(*span), format!("the `{link_name}` symbol is defined here"))],
207 Int2PtrWithStrictProvenance =>
208 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"))],
214 let title = match e.kind() {
215 UndefinedBehavior(_) =>
216 "Undefined Behavior",
217 ResourceExhaustion(_) =>
218 "resource exhaustion",
220 // We list only the ones that can actually happen.
221 UnsupportedOpInfo::Unsupported(_)
223 "unsupported operation",
225 // We list only the ones that can actually happen.
226 InvalidProgramInfo::AlreadyReported(_) |
227 InvalidProgramInfo::Layout(..)
229 "post-monomorphization error",
231 bug!("This error should be impossible in Miri: {kind:?}"),
234 let helps = match e.kind() {
236 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"))],
237 UndefinedBehavior(UndefinedBehaviorInfo::AlignmentCheckFailed { .. })
238 if ecx.machine.check_alignment == AlignmentCheck::Symbolic
241 (None, format!("this usually indicates that your program performed an invalid operation and caused Undefined Behavior")),
242 (None, format!("but due to `-Zmiri-symbolic-alignment-check`, alignment errors can also be false positives")),
244 UndefinedBehavior(_) =>
246 (None, format!("this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior")),
247 (None, format!("see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information")),
250 InvalidProgramInfo::AlreadyReported(rustc_errors::ErrorGuaranteed { .. })
252 // This got already reported. No point in reporting it again.
261 let stacktrace = ecx.generate_stacktrace();
262 let (stacktrace, was_pruned) = prune_stacktrace(stacktrace, &ecx.machine);
264 msg.insert(0, e.to_string());
267 &if let Some(title) = title { format!("{title}: {}", msg[0]) } else { msg[0].clone() },
275 // Include a note like `std` does when we omit frames from a backtrace
277 ecx.tcx.sess.diagnostic().note_without_error(
278 "some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace",
282 // Debug-dump all locals.
283 for (i, frame) in ecx.active_thread_stack().iter().enumerate() {
284 trace!("-------------------");
285 trace!("Frame {}", i);
286 trace!(" return: {:?}", *frame.return_place);
287 for (i, local) in frame.locals.iter().enumerate() {
288 trace!(" local {}: {:?}", i, local.value);
292 // Extra output to help debug specific issues.
294 UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(Some((alloc_id, access)))) => {
296 "Uninitialized memory occurred at {alloc_id:?}{range:?}, in this allocation:",
297 range = access.uninit,
299 eprintln!("{:?}", ecx.dump_alloc(*alloc_id));
307 /// Report an error or note (depending on the `error` argument) with the given stacktrace.
308 /// Also emits a full stacktrace of the interpreter stack.
309 /// We want to present a multi-line span message for some errors. Diagnostics do not support this
310 /// directly, so we pass the lines as a `Vec<String>` and display each line after the first with an
311 /// additional `span_label` or `note` call.
313 diag_level: DiagLevel,
315 span_msg: Vec<String>,
316 notes: Vec<(Option<SpanData>, String)>,
317 helps: Vec<(Option<SpanData>, String)>,
318 stacktrace: &[FrameInfo<'tcx>],
319 machine: &MiriMachine<'_, 'tcx>,
321 let span = stacktrace.first().map_or(DUMMY_SP, |fi| fi.span);
322 let sess = machine.tcx.sess;
323 let mut err = match diag_level {
324 DiagLevel::Error => sess.struct_span_err(span, title).forget_guarantee(),
325 DiagLevel::Warning => sess.struct_span_warn(span, title),
326 DiagLevel::Note => sess.diagnostic().span_note_diag(span, title),
329 // Show main message.
330 if span != DUMMY_SP {
331 for line in span_msg {
332 err.span_label(span, line);
335 // Make sure we show the message even when it is a dummy span.
336 for line in span_msg {
339 err.note("(no span available)");
342 // Show note and help messages.
343 for (span_data, note) in ¬es {
344 if let Some(span_data) = span_data {
345 err.span_note(span_data.span(), note);
350 for (span_data, help) in &helps {
351 if let Some(span_data) = span_data {
352 err.span_help(span_data.span(), help);
357 if notes.len() + helps.len() > 0 {
358 // Add visual separator before backtrace.
359 err.note("BACKTRACE:");
362 for (idx, frame_info) in stacktrace.iter().enumerate() {
363 let is_local = machine.is_local(frame_info);
364 // No span for non-local frames and the first frame (which is the error site).
365 if is_local && idx > 0 {
366 err.span_note(frame_info.span, &frame_info.to_string());
368 err.note(&frame_info.to_string());
375 impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
376 pub fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
377 use NonHaltingDiagnostic::*;
380 MiriInterpCx::generate_stacktrace_from_stack(self.threads.active_thread_stack());
381 let (stacktrace, _was_pruned) = prune_stacktrace(stacktrace, self);
383 let (title, diag_level) = match &e {
384 RejectedIsolatedOp(_) => ("operation rejected by isolation", DiagLevel::Warning),
385 Int2Ptr { .. } => ("integer-to-pointer cast", DiagLevel::Warning),
386 CreatedPointerTag(..)
387 | PoppedPointerTag(..)
391 | ProgressReport { .. }
392 | WeakMemoryOutdatedLoad => ("tracking was triggered", DiagLevel::Note),
396 CreatedPointerTag(tag, None, _) => format!("created base tag {tag:?}"),
397 CreatedPointerTag(tag, Some(kind), None) => format!("created {tag:?} for {kind}"),
398 CreatedPointerTag(tag, Some(kind), Some((alloc_id, range, orig_tag))) =>
400 "created tag {tag:?} for {kind} at {alloc_id:?}{range:?} derived from {orig_tag:?}"
402 PoppedPointerTag(item, tag) =>
404 None => format!("popped tracked tag for item {item:?} due to deallocation",),
405 Some((tag, access)) => {
407 "popped tracked tag for item {item:?} due to {access:?} access for {tag:?}",
411 CreatedCallId(id) => format!("function call with id {id}"),
412 CreatedAlloc(AllocId(id), size, align, kind) =>
414 "created {kind} allocation of {size} bytes (alignment {align} bytes) with id {id}",
416 align = align.bytes(),
418 FreedAlloc(AllocId(id)) => format!("freed allocation with id {id}"),
419 RejectedIsolatedOp(ref op) =>
420 format!("{op} was made to return an error due to isolation"),
421 ProgressReport { .. } =>
422 format!("progress report: current operation being executed is here"),
423 Int2Ptr { .. } => format!("integer-to-pointer cast"),
424 WeakMemoryOutdatedLoad =>
425 format!("weak memory emulation: outdated value returned from load"),
428 let notes = match &e {
429 ProgressReport { block_count } => {
430 // It is important that each progress report is slightly different, since
431 // identical diagnostics are being deduplicated.
432 vec![(None, format!("so far, {block_count} basic blocks have been executed"))]
437 let helps = match &e {
438 Int2Ptr { details: true } =>
443 "This program is using integer-to-pointer casts or (equivalently) `ptr::from_exposed_addr`,"
448 format!("which means that Miri might miss pointer bugs in this program."),
453 "See https://doc.rust-lang.org/nightly/std/ptr/fn.from_exposed_addr.html for more details on that operation."
459 "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."
465 "You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `from_exposed_addr` semantics."
471 "Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning."
478 report_msg(diag_level, title, vec![msg], notes, helps, &stacktrace, self);
482 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
483 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
484 fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
485 let this = self.eval_context_ref();
486 this.machine.emit_diagnostic(e);
489 /// We had a panic in Miri itself, try to print something useful.
490 fn handle_ice(&self) {
493 "Miri caused an ICE during evaluation. Here's the interpreter backtrace at the time of the panic:"
495 let this = self.eval_context_ref();
496 let stacktrace = this.generate_stacktrace();
499 "the place in the program where the ICE was triggered",