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 {
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. The string explains the reason.
71 PoppedPointerTag(Item, String),
72 CreatedCallId(CallId),
73 CreatedAlloc(AllocId, Size, Align, MemoryKind<MiriMemoryKind>),
75 RejectedIsolatedOp(String),
77 block_count: u64, // how many basic blocks have been run so far
82 WeakMemoryOutdatedLoad,
85 /// Level of Miri specific diagnostics
92 /// Attempts to prune a stacktrace to omit the Rust runtime, and returns a bool indicating if any
93 /// frames were pruned. If the stacktrace does not have any local frames, we conclude that it must
94 /// be pointing to a problem in the Rust runtime itself, and do not prune it at all.
95 fn prune_stacktrace<'tcx>(
96 mut stacktrace: Vec<FrameInfo<'tcx>>,
97 machine: &MiriMachine<'_, 'tcx>,
98 ) -> (Vec<FrameInfo<'tcx>>, bool) {
99 match machine.backtrace_style {
100 BacktraceStyle::Off => {
101 // Remove all frames marked with `caller_location` -- that attribute indicates we
102 // usually want to point at the caller, not them.
103 stacktrace.retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
104 // Retain one frame so that we can print a span for the error itself
105 stacktrace.truncate(1);
108 BacktraceStyle::Short => {
109 let original_len = stacktrace.len();
110 // Only prune frames if there is at least one local frame. This check ensures that if
111 // we get a backtrace that never makes it to the user code because it has detected a
112 // bug in the Rust runtime, we don't prune away every frame.
113 let has_local_frame = stacktrace.iter().any(|frame| machine.is_local(frame));
115 // Remove all frames marked with `caller_location` -- that attribute indicates we
116 // usually want to point at the caller, not them.
118 .retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
120 // This is part of the logic that `std` uses to select the relevant part of a
121 // backtrace. But here, we only look for __rust_begin_short_backtrace, not
122 // __rust_end_short_backtrace because the end symbol comes from a call to the default
124 stacktrace = stacktrace
126 .take_while(|frame| {
127 let def_id = frame.instance.def_id();
128 let path = machine.tcx.def_path_str(def_id);
129 !path.contains("__rust_begin_short_backtrace")
131 .collect::<Vec<_>>();
133 // After we prune frames from the bottom, there are a few left that are part of the
134 // Rust runtime. So we remove frames until we get to a local symbol, which should be
136 // This len check ensures that we don't somehow remove every frame, as doing so breaks
137 // the primary error message.
138 while stacktrace.len() > 1
139 && stacktrace.last().map_or(false, |frame| !machine.is_local(frame))
144 let was_pruned = stacktrace.len() != original_len;
145 (stacktrace, was_pruned)
147 BacktraceStyle::Full => (stacktrace, false),
151 /// Emit a custom diagnostic without going through the miri-engine machinery.
153 /// 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.
154 pub fn report_error<'tcx, 'mir>(
155 ecx: &InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>,
156 e: InterpErrorInfo<'tcx>,
157 ) -> Option<(i64, bool)> {
160 let mut msg = vec![];
162 let (title, helps) = if let MachineStop(info) = e.kind() {
163 let info = info.downcast_ref::<TerminationInfo>().expect("invalid MachineStop payload");
164 use TerminationInfo::*;
165 let title = match info {
166 Exit { code, leak_check } => return Some((*code, *leak_check)),
167 Abort(_) => Some("abnormal termination"),
168 UnsupportedInIsolation(_) | Int2PtrWithStrictProvenance =>
169 Some("unsupported operation"),
170 StackedBorrowsUb { .. } => Some("Undefined Behavior"),
171 Deadlock => Some("deadlock"),
172 MultipleSymbolDefinitions { .. } | SymbolShimClashing { .. } => None,
175 let helps = match info {
176 UnsupportedInIsolation(_) =>
178 (None, format!("pass the flag `-Zmiri-disable-isolation` to disable isolation;")),
179 (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")),
181 StackedBorrowsUb { help, history, .. } => {
182 let url = "https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md";
183 msg.extend(help.clone());
184 let mut helps = vec![
185 (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")),
186 (None, format!("see {url} for further information")),
188 if let Some(TagHistory {created, invalidated, protected}) = history.clone() {
189 helps.push((Some(created.1), created.0));
190 if let Some((msg, span)) = invalidated {
191 helps.push((Some(span), msg));
193 if let Some((protector_msg, protector_span)) = protected {
194 helps.push((Some(protector_span), protector_msg));
199 MultipleSymbolDefinitions { first, first_crate, second, second_crate, .. } =>
201 (Some(*first), format!("it's first defined here, in crate `{first_crate}`")),
202 (Some(*second), format!("then it's defined here again, in crate `{second_crate}`")),
204 SymbolShimClashing { link_name, span } =>
205 vec![(Some(*span), format!("the `{link_name}` symbol is defined here"))],
206 Int2PtrWithStrictProvenance =>
207 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"))],
213 let title = match e.kind() {
214 UndefinedBehavior(_) =>
215 "Undefined Behavior",
216 ResourceExhaustion(_) =>
217 "resource exhaustion",
219 // We list only the ones that can actually happen.
220 UnsupportedOpInfo::Unsupported(_)
222 "unsupported operation",
224 // We list only the ones that can actually happen.
225 InvalidProgramInfo::AlreadyReported(_) |
226 InvalidProgramInfo::Layout(..)
228 "post-monomorphization error",
230 bug!("This error should be impossible in Miri: {kind:?}"),
233 let helps = match e.kind() {
235 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"))],
236 UndefinedBehavior(UndefinedBehaviorInfo::AlignmentCheckFailed { .. })
237 if ecx.machine.check_alignment == AlignmentCheck::Symbolic
240 (None, format!("this usually indicates that your program performed an invalid operation and caused Undefined Behavior")),
241 (None, format!("but due to `-Zmiri-symbolic-alignment-check`, alignment errors can also be false positives")),
243 UndefinedBehavior(_) =>
245 (None, format!("this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior")),
246 (None, format!("see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information")),
249 InvalidProgramInfo::AlreadyReported(rustc_errors::ErrorGuaranteed { .. })
251 // This got already reported. No point in reporting it again.
260 let stacktrace = ecx.generate_stacktrace();
261 let (stacktrace, was_pruned) = prune_stacktrace(stacktrace, &ecx.machine);
263 msg.insert(0, e.to_string());
266 &if let Some(title) = title { format!("{title}: {}", msg[0]) } else { msg[0].clone() },
274 // Include a note like `std` does when we omit frames from a backtrace
276 ecx.tcx.sess.diagnostic().note_without_error(
277 "some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace",
281 // Debug-dump all locals.
282 for (i, frame) in ecx.active_thread_stack().iter().enumerate() {
283 trace!("-------------------");
284 trace!("Frame {}", i);
285 trace!(" return: {:?}", *frame.return_place);
286 for (i, local) in frame.locals.iter().enumerate() {
287 trace!(" local {}: {:?}", i, local.value);
291 // Extra output to help debug specific issues.
293 UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(Some((alloc_id, access)))) => {
295 "Uninitialized memory occurred at {alloc_id:?}{range:?}, in this allocation:",
296 range = access.uninit,
298 eprintln!("{:?}", ecx.dump_alloc(*alloc_id));
306 /// Report an error or note (depending on the `error` argument) with the given stacktrace.
307 /// Also emits a full stacktrace of the interpreter stack.
308 /// We want to present a multi-line span message for some errors. Diagnostics do not support this
309 /// directly, so we pass the lines as a `Vec<String>` and display each line after the first with an
310 /// additional `span_label` or `note` call.
312 diag_level: DiagLevel,
314 span_msg: Vec<String>,
315 notes: Vec<(Option<SpanData>, String)>,
316 helps: Vec<(Option<SpanData>, String)>,
317 stacktrace: &[FrameInfo<'tcx>],
318 machine: &MiriMachine<'_, 'tcx>,
320 let span = stacktrace.first().map_or(DUMMY_SP, |fi| fi.span);
321 let sess = machine.tcx.sess;
322 let mut err = match diag_level {
323 DiagLevel::Error => sess.struct_span_err(span, title).forget_guarantee(),
324 DiagLevel::Warning => sess.struct_span_warn(span, title),
325 DiagLevel::Note => sess.diagnostic().span_note_diag(span, title),
328 // Show main message.
329 if span != DUMMY_SP {
330 for line in span_msg {
331 err.span_label(span, line);
334 // Make sure we show the message even when it is a dummy span.
335 for line in span_msg {
338 err.note("(no span available)");
341 // Show note and help messages.
342 for (span_data, note) in ¬es {
343 if let Some(span_data) = span_data {
344 err.span_note(span_data.span(), note);
349 for (span_data, help) in &helps {
350 if let Some(span_data) = span_data {
351 err.span_help(span_data.span(), help);
356 if notes.len() + helps.len() > 0 {
357 // Add visual separator before backtrace.
358 err.note("BACKTRACE:");
361 for (idx, frame_info) in stacktrace.iter().enumerate() {
362 let is_local = machine.is_local(frame_info);
363 // No span for non-local frames and the first frame (which is the error site).
364 if is_local && idx > 0 {
365 err.span_note(frame_info.span, &frame_info.to_string());
367 err.note(&frame_info.to_string());
374 impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
375 pub fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
376 use NonHaltingDiagnostic::*;
379 MiriInterpCx::generate_stacktrace_from_stack(self.threads.active_thread_stack());
380 let (stacktrace, _was_pruned) = prune_stacktrace(stacktrace, self);
382 let (title, diag_level) = match &e {
383 RejectedIsolatedOp(_) => ("operation rejected by isolation", DiagLevel::Warning),
384 Int2Ptr { .. } => ("integer-to-pointer cast", DiagLevel::Warning),
385 CreatedPointerTag(..)
386 | PoppedPointerTag(..)
390 | ProgressReport { .. }
391 | WeakMemoryOutdatedLoad => ("tracking was triggered", DiagLevel::Note),
395 CreatedPointerTag(tag, None, _) => format!("created base tag {tag:?}"),
396 CreatedPointerTag(tag, Some(kind), None) => format!("created {tag:?} for {kind}"),
397 CreatedPointerTag(tag, Some(kind), Some((alloc_id, range, orig_tag))) =>
399 "created tag {tag:?} for {kind} at {alloc_id:?}{range:?} derived from {orig_tag:?}"
401 PoppedPointerTag(item, cause) => format!("popped tracked tag for item {item:?}{cause}"),
402 CreatedCallId(id) => format!("function call with id {id}"),
403 CreatedAlloc(AllocId(id), size, align, kind) =>
405 "created {kind} allocation of {size} bytes (alignment {align} bytes) with id {id}",
407 align = align.bytes(),
409 FreedAlloc(AllocId(id)) => format!("freed allocation with id {id}"),
410 RejectedIsolatedOp(ref op) =>
411 format!("{op} was made to return an error due to isolation"),
412 ProgressReport { .. } =>
413 format!("progress report: current operation being executed is here"),
414 Int2Ptr { .. } => format!("integer-to-pointer cast"),
415 WeakMemoryOutdatedLoad =>
416 format!("weak memory emulation: outdated value returned from load"),
419 let notes = match &e {
420 ProgressReport { block_count } => {
421 // It is important that each progress report is slightly different, since
422 // identical diagnostics are being deduplicated.
423 vec![(None, format!("so far, {block_count} basic blocks have been executed"))]
428 let helps = match &e {
429 Int2Ptr { details: true } =>
434 "This program is using integer-to-pointer casts or (equivalently) `ptr::from_exposed_addr`,"
439 format!("which means that Miri might miss pointer bugs in this program."),
444 "See https://doc.rust-lang.org/nightly/std/ptr/fn.from_exposed_addr.html for more details on that operation."
450 "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."
456 "You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `from_exposed_addr` semantics."
462 "Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning."
469 report_msg(diag_level, title, vec![msg], notes, helps, &stacktrace, self);
473 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
474 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
475 fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
476 let this = self.eval_context_ref();
477 this.machine.emit_diagnostic(e);
480 /// We had a panic in Miri itself, try to print something useful.
481 fn handle_ice(&self) {
484 "Miri caused an ICE during evaluation. Here's the interpreter backtrace at the time of the panic:"
486 let this = self.eval_context_ref();
487 let stacktrace = this.generate_stacktrace();
490 "the place in the program where the ICE was triggered",