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 CreatedPointerTag(NonZeroU64, Option<(AllocId, AllocRange)>),
64 /// This `Item` was popped from the borrow stack, either due to an access with the given tag or
65 /// a deallocation when the second argument is `None`.
66 PoppedPointerTag(Item, Option<(ProvenanceExtra, AccessKind)>),
67 CreatedCallId(CallId),
68 CreatedAlloc(AllocId, Size, Align, MemoryKind<MiriMemoryKind>),
70 RejectedIsolatedOp(String),
72 block_count: u64, // how many basic blocks have been run so far
77 WeakMemoryOutdatedLoad,
80 /// Level of Miri specific diagnostics
87 /// Attempts to prune a stacktrace to omit the Rust runtime, and returns a bool indicating if any
88 /// frames were pruned. If the stacktrace does not have any local frames, we conclude that it must
89 /// be pointing to a problem in the Rust runtime itself, and do not prune it at all.
90 fn prune_stacktrace<'tcx>(
91 mut stacktrace: Vec<FrameInfo<'tcx>>,
92 machine: &MiriMachine<'_, 'tcx>,
93 ) -> (Vec<FrameInfo<'tcx>>, bool) {
94 match machine.backtrace_style {
95 BacktraceStyle::Off => {
96 // Remove all frames marked with `caller_location` -- that attribute indicates we
97 // usually want to point at the caller, not them.
98 stacktrace.retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
99 // Retain one frame so that we can print a span for the error itself
100 stacktrace.truncate(1);
103 BacktraceStyle::Short => {
104 let original_len = stacktrace.len();
105 // Only prune frames if there is at least one local frame. This check ensures that if
106 // we get a backtrace that never makes it to the user code because it has detected a
107 // bug in the Rust runtime, we don't prune away every frame.
108 let has_local_frame = stacktrace.iter().any(|frame| machine.is_local(frame));
110 // Remove all frames marked with `caller_location` -- that attribute indicates we
111 // usually want to point at the caller, not them.
113 .retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
115 // This is part of the logic that `std` uses to select the relevant part of a
116 // backtrace. But here, we only look for __rust_begin_short_backtrace, not
117 // __rust_end_short_backtrace because the end symbol comes from a call to the default
119 stacktrace = stacktrace
121 .take_while(|frame| {
122 let def_id = frame.instance.def_id();
123 let path = machine.tcx.def_path_str(def_id);
124 !path.contains("__rust_begin_short_backtrace")
126 .collect::<Vec<_>>();
128 // After we prune frames from the bottom, there are a few left that are part of the
129 // Rust runtime. So we remove frames until we get to a local symbol, which should be
131 // This len check ensures that we don't somehow remove every frame, as doing so breaks
132 // the primary error message.
133 while stacktrace.len() > 1
134 && stacktrace.last().map_or(false, |frame| !machine.is_local(frame))
139 let was_pruned = stacktrace.len() != original_len;
140 (stacktrace, was_pruned)
142 BacktraceStyle::Full => (stacktrace, false),
146 /// Emit a custom diagnostic without going through the miri-engine machinery
147 pub fn report_error<'tcx, 'mir>(
148 ecx: &InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>,
149 e: InterpErrorInfo<'tcx>,
153 let mut msg = vec![];
155 let (title, helps) = match &e.kind() {
156 MachineStop(info) => {
157 let info = info.downcast_ref::<TerminationInfo>().expect("invalid MachineStop payload");
158 use TerminationInfo::*;
159 let title = match info {
160 Exit(code) => return Some(*code),
161 Abort(_) => Some("abnormal termination"),
162 UnsupportedInIsolation(_) | Int2PtrWithStrictProvenance =>
163 Some("unsupported operation"),
164 StackedBorrowsUb { .. } => Some("Undefined Behavior"),
165 Deadlock => Some("deadlock"),
166 MultipleSymbolDefinitions { .. } | SymbolShimClashing { .. } => None,
169 let helps = match info {
170 UnsupportedInIsolation(_) =>
172 (None, format!("pass the flag `-Zmiri-disable-isolation` to disable isolation;")),
173 (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")),
175 StackedBorrowsUb { help, history, .. } => {
176 let url = "https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md";
177 msg.extend(help.clone());
178 let mut helps = vec![
179 (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")),
180 (None, format!("see {url} for further information")),
182 if let Some(TagHistory {created, invalidated, protected}) = history.clone() {
183 helps.push((Some(created.1), created.0));
184 if let Some((msg, span)) = invalidated {
185 helps.push((Some(span), msg));
187 if let Some((protector_msg, protector_span)) = protected {
188 helps.push((Some(protector_span), protector_msg));
193 MultipleSymbolDefinitions { first, first_crate, second, second_crate, .. } =>
195 (Some(*first), format!("it's first defined here, in crate `{first_crate}`")),
196 (Some(*second), format!("then it's defined here again, in crate `{second_crate}`")),
198 SymbolShimClashing { link_name, span } =>
199 vec![(Some(*span), format!("the `{link_name}` symbol is defined here"))],
200 Int2PtrWithStrictProvenance =>
201 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"))],
208 let title = match e.kind() {
210 "unsupported operation",
211 UndefinedBehavior(_) =>
212 "Undefined Behavior",
213 ResourceExhaustion(_) =>
214 "resource exhaustion",
216 InvalidProgramInfo::AlreadyReported(_) |
217 InvalidProgramInfo::Layout(..) |
218 InvalidProgramInfo::ReferencedConstant
220 "post-monomorphization error",
222 bug!("This error should be impossible in Miri: {kind:?}"),
225 let helps = match e.kind() {
227 UnsupportedOpInfo::ThreadLocalStatic(_) |
228 UnsupportedOpInfo::ReadExternStatic(_) |
229 UnsupportedOpInfo::PartialPointerOverwrite(_) | // we make memory uninit instead
230 UnsupportedOpInfo::ReadPointerAsBytes
232 panic!("Error should never be raised by Miri: {kind:?}", kind = e.kind()),
234 UnsupportedOpInfo::Unsupported(_) |
235 UnsupportedOpInfo::PartialPointerCopy(_)
237 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"))],
238 UndefinedBehavior(UndefinedBehaviorInfo::AlignmentCheckFailed { .. })
239 if ecx.machine.check_alignment == AlignmentCheck::Symbolic
242 (None, format!("this usually indicates that your program performed an invalid operation and caused Undefined Behavior")),
243 (None, format!("but due to `-Zmiri-symbolic-alignment-check`, alignment errors can also be false positives")),
245 UndefinedBehavior(_) =>
247 (None, format!("this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior")),
248 (None, format!("see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information")),
250 InvalidProgram(_) | ResourceExhaustion(_) | MachineStop(_) =>
257 let stacktrace = ecx.generate_stacktrace();
258 let (stacktrace, was_pruned) = prune_stacktrace(stacktrace, &ecx.machine);
260 msg.insert(0, e.to_string());
263 &if let Some(title) = title { format!("{}: {}", title, msg[0]) } else { msg[0].clone() },
271 // Include a note like `std` does when we omit frames from a backtrace
273 ecx.tcx.sess.diagnostic().note_without_error(
274 "some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace",
278 // Debug-dump all locals.
279 for (i, frame) in ecx.active_thread_stack().iter().enumerate() {
280 trace!("-------------------");
281 trace!("Frame {}", i);
282 trace!(" return: {:?}", *frame.return_place);
283 for (i, local) in frame.locals.iter().enumerate() {
284 trace!(" local {}: {:?}", i, local.value);
288 // Extra output to help debug specific issues.
290 UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(Some((alloc_id, access)))) => {
292 "Uninitialized memory occurred at {alloc_id:?}{range:?}, in this allocation:",
293 range = access.uninit,
295 eprintln!("{:?}", ecx.dump_alloc(*alloc_id));
303 /// Report an error or note (depending on the `error` argument) with the given stacktrace.
304 /// Also emits a full stacktrace of the interpreter stack.
305 /// We want to present a multi-line span message for some errors. Diagnostics do not support this
306 /// directly, so we pass the lines as a `Vec<String>` and display each line after the first with an
307 /// additional `span_label` or `note` call.
309 diag_level: DiagLevel,
311 span_msg: Vec<String>,
312 notes: Vec<(Option<SpanData>, String)>,
313 helps: Vec<(Option<SpanData>, String)>,
314 stacktrace: &[FrameInfo<'tcx>],
315 machine: &MiriMachine<'_, 'tcx>,
317 let span = stacktrace.first().map_or(DUMMY_SP, |fi| fi.span);
318 let sess = machine.tcx.sess;
319 let mut err = match diag_level {
320 DiagLevel::Error => sess.struct_span_err(span, title).forget_guarantee(),
321 DiagLevel::Warning => sess.struct_span_warn(span, title),
322 DiagLevel::Note => sess.diagnostic().span_note_diag(span, title),
325 // Show main message.
326 if span != DUMMY_SP {
327 for line in span_msg {
328 err.span_label(span, line);
331 // Make sure we show the message even when it is a dummy span.
332 for line in span_msg {
335 err.note("(no span available)");
338 // Show note and help messages.
339 for (span_data, note) in ¬es {
340 if let Some(span_data) = span_data {
341 err.span_note(span_data.span(), note);
346 for (span_data, help) in &helps {
347 if let Some(span_data) = span_data {
348 err.span_help(span_data.span(), help);
353 if notes.len() + helps.len() > 0 {
354 // Add visual separator before backtrace.
355 err.note("BACKTRACE:");
358 for (idx, frame_info) in stacktrace.iter().enumerate() {
359 let is_local = machine.is_local(frame_info);
360 // No span for non-local frames and the first frame (which is the error site).
361 if is_local && idx > 0 {
362 err.span_note(frame_info.span, &frame_info.to_string());
364 err.note(&frame_info.to_string());
371 impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
372 pub fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
373 use NonHaltingDiagnostic::*;
376 MiriInterpCx::generate_stacktrace_from_stack(self.threads.active_thread_stack());
377 let (stacktrace, _was_pruned) = prune_stacktrace(stacktrace, self);
379 let (title, diag_level) = match e {
380 RejectedIsolatedOp(_) => ("operation rejected by isolation", DiagLevel::Warning),
381 Int2Ptr { .. } => ("integer-to-pointer cast", DiagLevel::Warning),
382 CreatedPointerTag(..)
383 | PoppedPointerTag(..)
387 | ProgressReport { .. }
388 | WeakMemoryOutdatedLoad => ("tracking was triggered", DiagLevel::Note),
392 CreatedPointerTag(tag, None) => format!("created tag {tag:?}"),
393 CreatedPointerTag(tag, Some((alloc_id, range))) =>
394 format!("created tag {tag:?} at {alloc_id:?}{range:?}"),
395 PoppedPointerTag(item, tag) =>
397 None => format!("popped tracked tag for item {item:?} due to deallocation",),
398 Some((tag, access)) => {
400 "popped tracked tag for item {item:?} due to {access:?} access for {tag:?}",
404 CreatedCallId(id) => format!("function call with id {id}"),
405 CreatedAlloc(AllocId(id), size, align, kind) =>
407 "created {kind} allocation of {size} bytes (alignment {align} bytes) with id {id}",
409 align = align.bytes(),
411 FreedAlloc(AllocId(id)) => format!("freed allocation with id {id}"),
412 RejectedIsolatedOp(ref op) =>
413 format!("{op} was made to return an error due to isolation"),
414 ProgressReport { .. } =>
415 format!("progress report: current operation being executed is here"),
416 Int2Ptr { .. } => format!("integer-to-pointer cast"),
417 WeakMemoryOutdatedLoad =>
418 format!("weak memory emulation: outdated value returned from load"),
421 let notes = match e {
422 ProgressReport { block_count } => {
423 // It is important that each progress report is slightly different, since
424 // identical diagnostics are being deduplicated.
425 vec![(None, format!("so far, {block_count} basic blocks have been executed"))]
430 let helps = match e {
431 Int2Ptr { details: true } =>
436 "This program is using integer-to-pointer casts or (equivalently) `ptr::from_exposed_addr`,"
441 format!("which means that Miri might miss pointer bugs in this program."),
446 "See https://doc.rust-lang.org/nightly/std/ptr/fn.from_exposed_addr.html for more details on that operation."
452 "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."
458 "You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `from_exposed_addr` semantics."
464 "Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning."
471 report_msg(diag_level, title, vec![msg], notes, helps, &stacktrace, self);
475 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
476 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
477 fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
478 let this = self.eval_context_ref();
479 this.machine.emit_diagnostic(e);
482 /// We had a panic in Miri itself, try to print something useful.
483 fn handle_ice(&self) {
486 "Miri caused an ICE during evaluation. Here's the interpreter backtrace at the time of the panic:"
488 let this = self.eval_context_ref();
489 let stacktrace = this.generate_stacktrace();
492 "the place in the program where the ICE was triggered",