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::borrow_tracker::stacked_borrows::diagnostics::TagHistory;
12 /// Details of premature program termination.
13 pub enum TerminationInfo {
19 UnsupportedInIsolation(String),
23 history: Option<TagHistory>,
25 Int2PtrWithStrictProvenance,
27 MultipleSymbolDefinitions {
47 pub thread_info: String,
51 impl fmt::Display for TerminationInfo {
52 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
53 use TerminationInfo::*;
55 Exit { code, .. } => write!(f, "the evaluated program completed with exit code {code}"),
56 Abort(msg) => write!(f, "{msg}"),
57 UnsupportedInIsolation(msg) => write!(f, "{msg}"),
58 Int2PtrWithStrictProvenance =>
61 "integer-to-pointer casts and `ptr::from_exposed_addr` are not supported with `-Zmiri-strict-provenance`"
63 StackedBorrowsUb { msg, .. } => write!(f, "{msg}"),
64 Deadlock => write!(f, "the evaluated program deadlocked"),
65 MultipleSymbolDefinitions { link_name, .. } =>
66 write!(f, "multiple definitions of symbol `{link_name}`"),
67 SymbolShimClashing { link_name, .. } =>
68 write!(f, "found `{link_name}` symbol definition that clashes with a built-in shim",),
69 DataRace { ptr, op1, op2 } =>
72 "Data race detected between (1) {} on {} and (2) {} on {} at {ptr:?}. (2) just happened here",
73 op1.action, op1.thread_info, op2.action, op2.thread_info
79 impl MachineStopType for TerminationInfo {}
81 /// Miri specific diagnostics
82 pub enum NonHaltingDiagnostic {
83 /// (new_tag, new_perm, (alloc_id, base_offset, orig_tag))
85 /// new_perm is `None` for base tags.
86 CreatedPointerTag(NonZeroU64, Option<String>, Option<(AllocId, AllocRange, ProvenanceExtra)>),
87 /// This `Item` was popped from the borrow stack. The string explains the reason.
88 PoppedPointerTag(Item, String),
89 CreatedCallId(CallId),
90 CreatedAlloc(AllocId, Size, Align, MemoryKind<MiriMemoryKind>),
92 RejectedIsolatedOp(String),
94 block_count: u64, // how many basic blocks have been run so far
99 WeakMemoryOutdatedLoad,
102 /// Level of Miri specific diagnostics
109 /// Attempts to prune a stacktrace to omit the Rust runtime, and returns a bool indicating if any
110 /// frames were pruned. If the stacktrace does not have any local frames, we conclude that it must
111 /// be pointing to a problem in the Rust runtime itself, and do not prune it at all.
112 fn prune_stacktrace<'tcx>(
113 mut stacktrace: Vec<FrameInfo<'tcx>>,
114 machine: &MiriMachine<'_, 'tcx>,
115 ) -> (Vec<FrameInfo<'tcx>>, bool) {
116 match machine.backtrace_style {
117 BacktraceStyle::Off => {
118 // Remove all frames marked with `caller_location` -- that attribute indicates we
119 // usually want to point at the caller, not them.
120 stacktrace.retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
121 // Retain one frame so that we can print a span for the error itself
122 stacktrace.truncate(1);
125 BacktraceStyle::Short => {
126 let original_len = stacktrace.len();
127 // Only prune frames if there is at least one local frame. This check ensures that if
128 // we get a backtrace that never makes it to the user code because it has detected a
129 // bug in the Rust runtime, we don't prune away every frame.
130 let has_local_frame = stacktrace.iter().any(|frame| machine.is_local(frame));
132 // Remove all frames marked with `caller_location` -- that attribute indicates we
133 // usually want to point at the caller, not them.
135 .retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
137 // This is part of the logic that `std` uses to select the relevant part of a
138 // backtrace. But here, we only look for __rust_begin_short_backtrace, not
139 // __rust_end_short_backtrace because the end symbol comes from a call to the default
141 stacktrace = stacktrace
143 .take_while(|frame| {
144 let def_id = frame.instance.def_id();
145 let path = machine.tcx.def_path_str(def_id);
146 !path.contains("__rust_begin_short_backtrace")
148 .collect::<Vec<_>>();
150 // After we prune frames from the bottom, there are a few left that are part of the
151 // Rust runtime. So we remove frames until we get to a local symbol, which should be
153 // This len check ensures that we don't somehow remove every frame, as doing so breaks
154 // the primary error message.
155 while stacktrace.len() > 1
156 && stacktrace.last().map_or(false, |frame| !machine.is_local(frame))
161 let was_pruned = stacktrace.len() != original_len;
162 (stacktrace, was_pruned)
164 BacktraceStyle::Full => (stacktrace, false),
168 /// Emit a custom diagnostic without going through the miri-engine machinery.
170 /// 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.
171 pub fn report_error<'tcx, 'mir>(
172 ecx: &InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>,
173 e: InterpErrorInfo<'tcx>,
174 ) -> Option<(i64, bool)> {
177 let mut msg = vec![];
179 let (title, helps) = if let MachineStop(info) = e.kind() {
180 let info = info.downcast_ref::<TerminationInfo>().expect("invalid MachineStop payload");
181 use TerminationInfo::*;
182 let title = match info {
183 Exit { code, leak_check } => return Some((*code, *leak_check)),
184 Abort(_) => Some("abnormal termination"),
185 UnsupportedInIsolation(_) | Int2PtrWithStrictProvenance =>
186 Some("unsupported operation"),
187 StackedBorrowsUb { .. } | DataRace { .. } => Some("Undefined Behavior"),
188 Deadlock => Some("deadlock"),
189 MultipleSymbolDefinitions { .. } | SymbolShimClashing { .. } => None,
192 let helps = match info {
193 UnsupportedInIsolation(_) =>
195 (None, format!("pass the flag `-Zmiri-disable-isolation` to disable isolation;")),
196 (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")),
198 StackedBorrowsUb { help, history, .. } => {
199 let url = "https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md";
200 msg.extend(help.clone());
201 let mut helps = vec![
202 (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")),
203 (None, format!("see {url} for further information")),
205 if let Some(TagHistory {created, invalidated, protected}) = history.clone() {
206 helps.push((Some(created.1), created.0));
207 if let Some((msg, span)) = invalidated {
208 helps.push((Some(span), msg));
210 if let Some((protector_msg, protector_span)) = protected {
211 helps.push((Some(protector_span), protector_msg));
216 MultipleSymbolDefinitions { first, first_crate, second, second_crate, .. } =>
218 (Some(*first), format!("it's first defined here, in crate `{first_crate}`")),
219 (Some(*second), format!("then it's defined here again, in crate `{second_crate}`")),
221 SymbolShimClashing { link_name, span } =>
222 vec![(Some(*span), format!("the `{link_name}` symbol is defined here"))],
223 Int2PtrWithStrictProvenance =>
224 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"))],
225 DataRace { op1, .. } =>
227 (Some(op1.span), format!("and (1) occurred earlier here")),
228 (None, format!("this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior")),
229 (None, format!("see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information")),
236 let title = match e.kind() {
237 UndefinedBehavior(_) =>
238 "Undefined Behavior",
239 ResourceExhaustion(_) =>
240 "resource exhaustion",
242 // We list only the ones that can actually happen.
243 UnsupportedOpInfo::Unsupported(_)
245 "unsupported operation",
247 // We list only the ones that can actually happen.
248 InvalidProgramInfo::AlreadyReported(_) |
249 InvalidProgramInfo::Layout(..)
251 "post-monomorphization error",
253 bug!("This error should be impossible in Miri: {kind:?}"),
256 let helps = match e.kind() {
258 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"))],
259 UndefinedBehavior(UndefinedBehaviorInfo::AlignmentCheckFailed { .. })
260 if ecx.machine.check_alignment == AlignmentCheck::Symbolic
263 (None, format!("this usually indicates that your program performed an invalid operation and caused Undefined Behavior")),
264 (None, format!("but due to `-Zmiri-symbolic-alignment-check`, alignment errors can also be false positives")),
266 UndefinedBehavior(_) =>
268 (None, format!("this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior")),
269 (None, format!("see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information")),
272 InvalidProgramInfo::AlreadyReported(rustc_errors::ErrorGuaranteed { .. })
274 // This got already reported. No point in reporting it again.
283 let stacktrace = ecx.generate_stacktrace();
284 let (stacktrace, was_pruned) = prune_stacktrace(stacktrace, &ecx.machine);
286 msg.insert(0, e.to_string());
289 &if let Some(title) = title { format!("{title}: {}", msg[0]) } else { msg[0].clone() },
297 // Include a note like `std` does when we omit frames from a backtrace
299 ecx.tcx.sess.diagnostic().note_without_error(
300 "some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace",
304 // Debug-dump all locals.
305 for (i, frame) in ecx.active_thread_stack().iter().enumerate() {
306 trace!("-------------------");
307 trace!("Frame {}", i);
308 trace!(" return: {:?}", *frame.return_place);
309 for (i, local) in frame.locals.iter().enumerate() {
310 trace!(" local {}: {:?}", i, local.value);
314 // Extra output to help debug specific issues.
316 UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(Some((alloc_id, access)))) => {
318 "Uninitialized memory occurred at {alloc_id:?}{range:?}, in this allocation:",
319 range = access.uninit,
321 eprintln!("{:?}", ecx.dump_alloc(*alloc_id));
329 /// Report an error or note (depending on the `error` argument) with the given stacktrace.
330 /// Also emits a full stacktrace of the interpreter stack.
331 /// We want to present a multi-line span message for some errors. Diagnostics do not support this
332 /// directly, so we pass the lines as a `Vec<String>` and display each line after the first with an
333 /// additional `span_label` or `note` call.
335 diag_level: DiagLevel,
337 span_msg: Vec<String>,
338 notes: Vec<(Option<SpanData>, String)>,
339 helps: Vec<(Option<SpanData>, String)>,
340 stacktrace: &[FrameInfo<'tcx>],
341 machine: &MiriMachine<'_, 'tcx>,
343 let span = stacktrace.first().map_or(DUMMY_SP, |fi| fi.span);
344 let sess = machine.tcx.sess;
345 let mut err = match diag_level {
346 DiagLevel::Error => sess.struct_span_err(span, title).forget_guarantee(),
347 DiagLevel::Warning => sess.struct_span_warn(span, title),
348 DiagLevel::Note => sess.diagnostic().span_note_diag(span, title),
351 // Show main message.
352 if span != DUMMY_SP {
353 for line in span_msg {
354 err.span_label(span, line);
357 // Make sure we show the message even when it is a dummy span.
358 for line in span_msg {
361 err.note("(no span available)");
364 // Show note and help messages.
365 let mut extra_span = false;
366 for (span_data, note) in ¬es {
367 if let Some(span_data) = span_data {
368 err.span_note(span_data.span(), note);
374 for (span_data, help) in &helps {
375 if let Some(span_data) = span_data {
376 err.span_help(span_data.span(), help);
382 if notes.len() + helps.len() > 0 {
383 // Add visual separator before backtrace.
384 err.note(if extra_span { "BACKTRACE (of the first span):" } else { "BACKTRACE:" });
387 for (idx, frame_info) in stacktrace.iter().enumerate() {
388 let is_local = machine.is_local(frame_info);
389 // No span for non-local frames and the first frame (which is the error site).
390 if is_local && idx > 0 {
391 err.span_note(frame_info.span, &frame_info.to_string());
393 let sm = sess.source_map();
394 let span = sm.span_to_embeddable_string(frame_info.span);
395 err.note(format!("{frame_info} at {span}"));
402 impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
403 pub fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
404 use NonHaltingDiagnostic::*;
407 MiriInterpCx::generate_stacktrace_from_stack(self.threads.active_thread_stack());
408 let (stacktrace, _was_pruned) = prune_stacktrace(stacktrace, self);
410 let (title, diag_level) = match &e {
411 RejectedIsolatedOp(_) => ("operation rejected by isolation", DiagLevel::Warning),
412 Int2Ptr { .. } => ("integer-to-pointer cast", DiagLevel::Warning),
413 CreatedPointerTag(..)
414 | PoppedPointerTag(..)
418 | ProgressReport { .. }
419 | WeakMemoryOutdatedLoad => ("tracking was triggered", DiagLevel::Note),
423 CreatedPointerTag(tag, None, _) => format!("created base tag {tag:?}"),
424 CreatedPointerTag(tag, Some(perm), None) =>
425 format!("created {tag:?} with {perm} derived from unknown tag"),
426 CreatedPointerTag(tag, Some(perm), Some((alloc_id, range, orig_tag))) =>
428 "created tag {tag:?} with {perm} at {alloc_id:?}{range:?} derived from {orig_tag:?}"
430 PoppedPointerTag(item, cause) => format!("popped tracked tag for item {item:?}{cause}"),
431 CreatedCallId(id) => format!("function call with id {id}"),
432 CreatedAlloc(AllocId(id), size, align, kind) =>
434 "created {kind} allocation of {size} bytes (alignment {align} bytes) with id {id}",
436 align = align.bytes(),
438 FreedAlloc(AllocId(id)) => format!("freed allocation with id {id}"),
439 RejectedIsolatedOp(ref op) =>
440 format!("{op} was made to return an error due to isolation"),
441 ProgressReport { .. } =>
442 format!("progress report: current operation being executed is here"),
443 Int2Ptr { .. } => format!("integer-to-pointer cast"),
444 WeakMemoryOutdatedLoad =>
445 format!("weak memory emulation: outdated value returned from load"),
448 let notes = match &e {
449 ProgressReport { block_count } => {
450 // It is important that each progress report is slightly different, since
451 // identical diagnostics are being deduplicated.
452 vec![(None, format!("so far, {block_count} basic blocks have been executed"))]
457 let helps = match &e {
458 Int2Ptr { details: true } =>
463 "This program is using integer-to-pointer casts or (equivalently) `ptr::from_exposed_addr`,"
468 format!("which means that Miri might miss pointer bugs in this program."),
473 "See https://doc.rust-lang.org/nightly/std/ptr/fn.from_exposed_addr.html for more details on that operation."
479 "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."
485 "You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `from_exposed_addr` semantics."
491 "Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning."
498 report_msg(diag_level, title, vec![msg], notes, helps, &stacktrace, self);
502 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
503 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
504 fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
505 let this = self.eval_context_ref();
506 this.machine.emit_diagnostic(e);
509 /// We had a panic in Miri itself, try to print something useful.
510 fn handle_ice(&self) {
513 "Miri caused an ICE during evaluation. Here's the interpreter backtrace at the time of the panic:"
515 let this = self.eval_context_ref();
516 let stacktrace = this.generate_stacktrace();
519 "the place in the program where the ICE was triggered",