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use std::cell::RefCell;
use std::fmt;
use std::num::NonZeroU64;
use log::trace;
use rustc_middle::ty;
use rustc_span::{source_map::DUMMY_SP, Span, SpanData, Symbol};
use rustc_target::abi::{Align, Size};
use crate::stacked_borrows::{diagnostics::TagHistory, AccessKind};
use crate::*;
pub enum TerminationInfo {
Exit(i64),
Abort(String),
UnsupportedInIsolation(String),
StackedBorrowsUb {
msg: String,
help: Option<String>,
history: Option<TagHistory>,
},
Int2PtrWithStrictProvenance,
Deadlock,
MultipleSymbolDefinitions {
link_name: Symbol,
first: SpanData,
first_crate: Symbol,
second: SpanData,
second_crate: Symbol,
},
SymbolShimClashing {
link_name: Symbol,
span: SpanData,
},
}
impl fmt::Display for TerminationInfo {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use TerminationInfo::*;
match self {
Exit(code) => write!(f, "the evaluated program completed with exit code {code}"),
Abort(msg) => write!(f, "{msg}"),
UnsupportedInIsolation(msg) => write!(f, "{msg}"),
Int2PtrWithStrictProvenance =>
write!(
f,
"integer-to-pointer casts and `ptr::from_exposed_addr` are not supported with `-Zmiri-strict-provenance`"
),
StackedBorrowsUb { msg, .. } => write!(f, "{msg}"),
Deadlock => write!(f, "the evaluated program deadlocked"),
MultipleSymbolDefinitions { link_name, .. } =>
write!(f, "multiple definitions of symbol `{link_name}`"),
SymbolShimClashing { link_name, .. } =>
write!(f, "found `{link_name}` symbol definition that clashes with a built-in shim",),
}
}
}
impl MachineStopType for TerminationInfo {}
pub enum NonHaltingDiagnostic {
CreatedPointerTag(NonZeroU64, Option<(AllocId, AllocRange)>),
PoppedPointerTag(Item, Option<(ProvenanceExtra, AccessKind)>),
CreatedCallId(CallId),
CreatedAlloc(AllocId, Size, Align, MemoryKind<MiriMemoryKind>),
FreedAlloc(AllocId),
RejectedIsolatedOp(String),
ProgressReport {
block_count: u64, },
Int2Ptr {
details: bool,
},
WeakMemoryOutdatedLoad,
}
enum DiagLevel {
Error,
Warning,
Note,
}
fn prune_stacktrace<'mir, 'tcx>(
ecx: &InterpCx<'mir, 'tcx, Evaluator<'mir, 'tcx>>,
mut stacktrace: Vec<FrameInfo<'tcx>>,
) -> (Vec<FrameInfo<'tcx>>, bool) {
match ecx.machine.backtrace_style {
BacktraceStyle::Off => {
stacktrace.retain(|frame| !frame.instance.def.requires_caller_location(*ecx.tcx));
stacktrace.truncate(1);
(stacktrace, false)
}
BacktraceStyle::Short => {
let original_len = stacktrace.len();
let has_local_frame = stacktrace.iter().any(|frame| ecx.machine.is_local(frame));
if has_local_frame {
stacktrace.retain(|frame| !frame.instance.def.requires_caller_location(*ecx.tcx));
stacktrace = stacktrace
.into_iter()
.take_while(|frame| {
let def_id = frame.instance.def_id();
let path = ecx.tcx.tcx.def_path_str(def_id);
!path.contains("__rust_begin_short_backtrace")
})
.collect::<Vec<_>>();
while stacktrace.len() > 1
&& stacktrace.last().map_or(false, |frame| !ecx.machine.is_local(frame))
{
stacktrace.pop();
}
}
let was_pruned = stacktrace.len() != original_len;
(stacktrace, was_pruned)
}
BacktraceStyle::Full => (stacktrace, false),
}
}
pub fn report_error<'tcx, 'mir>(
ecx: &InterpCx<'mir, 'tcx, Evaluator<'mir, 'tcx>>,
e: InterpErrorInfo<'tcx>,
) -> Option<i64> {
use InterpError::*;
let mut msg = vec![];
let (title, helps) = match &e.kind() {
MachineStop(info) => {
let info = info.downcast_ref::<TerminationInfo>().expect("invalid MachineStop payload");
use TerminationInfo::*;
let title = match info {
Exit(code) => return Some(*code),
Abort(_) => Some("abnormal termination"),
UnsupportedInIsolation(_) | Int2PtrWithStrictProvenance =>
Some("unsupported operation"),
StackedBorrowsUb { .. } => Some("Undefined Behavior"),
Deadlock => Some("deadlock"),
MultipleSymbolDefinitions { .. } | SymbolShimClashing { .. } => None,
};
#[rustfmt::skip]
let helps = match info {
UnsupportedInIsolation(_) =>
vec![
(None, format!("pass the flag `-Zmiri-disable-isolation` to disable isolation;")),
(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")),
],
StackedBorrowsUb { help, history, .. } => {
let url = "https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md";
msg.extend(help.clone());
let mut helps = vec![
(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")),
(None, format!("see {url} for further information")),
];
if let Some(TagHistory {created, invalidated, protected}) = history.clone() {
helps.push((Some(created.1), created.0));
if let Some((msg, span)) = invalidated {
helps.push((Some(span), msg));
}
if let Some((protector_msg, protector_span)) = protected {
helps.push((Some(protector_span), protector_msg));
}
}
helps
}
MultipleSymbolDefinitions { first, first_crate, second, second_crate, .. } =>
vec![
(Some(*first), format!("it's first defined here, in crate `{first_crate}`")),
(Some(*second), format!("then it's defined here again, in crate `{second_crate}`")),
],
SymbolShimClashing { link_name, span } =>
vec![(Some(*span), format!("the `{link_name}` symbol is defined here"))],
Int2PtrWithStrictProvenance =>
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"))],
_ => vec![],
};
(title, helps)
}
_ => {
#[rustfmt::skip]
let title = match e.kind() {
Unsupported(_) =>
"unsupported operation",
UndefinedBehavior(_) =>
"Undefined Behavior",
ResourceExhaustion(_) =>
"resource exhaustion",
InvalidProgram(
InvalidProgramInfo::AlreadyReported(_) |
InvalidProgramInfo::Layout(..) |
InvalidProgramInfo::ReferencedConstant
) =>
"post-monomorphization error",
kind =>
bug!("This error should be impossible in Miri: {kind:?}"),
};
#[rustfmt::skip]
let helps = match e.kind() {
Unsupported(
UnsupportedOpInfo::ThreadLocalStatic(_) |
UnsupportedOpInfo::ReadExternStatic(_) |
UnsupportedOpInfo::PartialPointerOverwrite(_) | UnsupportedOpInfo::ReadPointerAsBytes
) =>
panic!("Error should never be raised by Miri: {kind:?}", kind = e.kind()),
Unsupported(
UnsupportedOpInfo::Unsupported(_) |
UnsupportedOpInfo::PartialPointerCopy(_)
) =>
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"))],
UndefinedBehavior(UndefinedBehaviorInfo::AlignmentCheckFailed { .. })
if ecx.machine.check_alignment == AlignmentCheck::Symbolic
=>
vec![
(None, format!("this usually indicates that your program performed an invalid operation and caused Undefined Behavior")),
(None, format!("but due to `-Zmiri-symbolic-alignment-check`, alignment errors can also be false positives")),
],
UndefinedBehavior(_) =>
vec![
(None, format!("this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior")),
(None, format!("see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information")),
],
InvalidProgram(_) | ResourceExhaustion(_) | MachineStop(_) =>
vec![],
};
(Some(title), helps)
}
};
let stacktrace = ecx.generate_stacktrace();
let (stacktrace, was_pruned) = prune_stacktrace(ecx, stacktrace);
e.print_backtrace();
msg.insert(0, e.to_string());
report_msg(
ecx,
DiagLevel::Error,
&if let Some(title) = title { format!("{}: {}", title, msg[0]) } else { msg[0].clone() },
msg,
vec![],
helps,
&stacktrace,
);
if was_pruned {
ecx.tcx.sess.diagnostic().note_without_error(
"some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace",
);
}
for (i, frame) in ecx.active_thread_stack().iter().enumerate() {
trace!("-------------------");
trace!("Frame {}", i);
trace!(" return: {:?}", *frame.return_place);
for (i, local) in frame.locals.iter().enumerate() {
trace!(" local {}: {:?}", i, local.value);
}
}
match e.kind() {
UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(Some((alloc_id, access)))) => {
eprintln!(
"Uninitialized memory occurred at {alloc_id:?}{range:?}, in this allocation:",
range = access.uninit,
);
eprintln!("{:?}", ecx.dump_alloc(*alloc_id));
}
_ => {}
}
None
}
fn report_msg<'mir, 'tcx>(
ecx: &InterpCx<'mir, 'tcx, Evaluator<'mir, 'tcx>>,
diag_level: DiagLevel,
title: &str,
span_msg: Vec<String>,
notes: Vec<(Option<SpanData>, String)>,
helps: Vec<(Option<SpanData>, String)>,
stacktrace: &[FrameInfo<'tcx>],
) {
let span = stacktrace.first().map_or(DUMMY_SP, |fi| fi.span);
let sess = ecx.tcx.sess;
let mut err = match diag_level {
DiagLevel::Error => sess.struct_span_err(span, title).forget_guarantee(),
DiagLevel::Warning => sess.struct_span_warn(span, title),
DiagLevel::Note => sess.diagnostic().span_note_diag(span, title),
};
if span != DUMMY_SP {
for line in span_msg {
err.span_label(span, line);
}
} else {
for line in span_msg {
err.note(&line);
}
err.note("(no span available)");
}
for (span_data, note) in ¬es {
if let Some(span_data) = span_data {
err.span_note(span_data.span(), note);
} else {
err.note(note);
}
}
for (span_data, help) in &helps {
if let Some(span_data) = span_data {
err.span_help(span_data.span(), help);
} else {
err.help(help);
}
}
if notes.len() + helps.len() > 0 {
err.note("BACKTRACE:");
}
for (idx, frame_info) in stacktrace.iter().enumerate() {
let is_local = ecx.machine.is_local(frame_info);
if is_local && idx > 0 {
err.span_note(frame_info.span, &frame_info.to_string());
} else {
err.note(&frame_info.to_string());
}
}
err.emit();
}
thread_local! {
static DIAGNOSTICS: RefCell<Vec<NonHaltingDiagnostic>> = RefCell::new(Vec::new());
}
pub fn register_diagnostic(e: NonHaltingDiagnostic) {
DIAGNOSTICS.with(|diagnostics| diagnostics.borrow_mut().push(e));
}
pub struct TopFrameInfo<'tcx> {
stack_size: usize,
instance: Option<ty::Instance<'tcx>>,
span: Span,
}
impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
fn preprocess_diagnostics(&self) -> TopFrameInfo<'tcx> {
DIAGNOSTICS.with(|diagnostics| assert!(diagnostics.borrow().is_empty()));
let this = self.eval_context_ref();
if this.active_thread_stack().is_empty() {
return TopFrameInfo { stack_size: 0, instance: None, span: DUMMY_SP };
}
let frame = this.frame();
TopFrameInfo {
stack_size: this.active_thread_stack().len(),
instance: Some(frame.instance),
span: frame.current_span(),
}
}
fn process_diagnostics(&self, info: TopFrameInfo<'tcx>) {
let this = self.eval_context_ref();
DIAGNOSTICS.with(|diagnostics| {
let mut diagnostics = diagnostics.borrow_mut();
if diagnostics.is_empty() {
return;
}
let mut stacktrace = this.generate_stacktrace();
while stacktrace.len() > info.stack_size {
stacktrace.remove(0);
}
if stacktrace.len() < info.stack_size {
assert!(
stacktrace.len() == info.stack_size - 1,
"we should never pop more than one frame at once"
);
let frame_info = FrameInfo {
instance: info.instance.unwrap(),
span: info.span,
lint_root: None,
};
stacktrace.insert(0, frame_info);
} else if let Some(instance) = info.instance {
stacktrace[0].span = info.span;
assert_eq!(
stacktrace[0].instance, instance,
"we should not pop and push a frame in one step"
);
}
let (stacktrace, _was_pruned) = prune_stacktrace(this, stacktrace);
for e in diagnostics.drain(..) {
use NonHaltingDiagnostic::*;
let (title, diag_level) = match e {
RejectedIsolatedOp(_) =>
("operation rejected by isolation", DiagLevel::Warning),
Int2Ptr { .. } => ("integer-to-pointer cast", DiagLevel::Warning),
CreatedPointerTag(..)
| PoppedPointerTag(..)
| CreatedCallId(..)
| CreatedAlloc(..)
| FreedAlloc(..)
| ProgressReport { .. }
| WeakMemoryOutdatedLoad =>
("tracking was triggered", DiagLevel::Note),
};
let msg = match e {
CreatedPointerTag(tag, None) =>
format!("created tag {tag:?}"),
CreatedPointerTag(tag, Some((alloc_id, range))) =>
format!("created tag {tag:?} at {alloc_id:?}{range:?}"),
PoppedPointerTag(item, tag) =>
match tag {
None =>
format!(
"popped tracked tag for item {item:?} due to deallocation",
),
Some((tag, access)) => {
format!(
"popped tracked tag for item {item:?} due to {access:?} access for {tag:?}",
)
}
},
CreatedCallId(id) =>
format!("function call with id {id}"),
CreatedAlloc(AllocId(id), size, align, kind) =>
format!(
"created {kind} allocation of {size} bytes (alignment {align} bytes) with id {id}",
size = size.bytes(),
align = align.bytes(),
),
FreedAlloc(AllocId(id)) =>
format!("freed allocation with id {id}"),
RejectedIsolatedOp(ref op) =>
format!("{op} was made to return an error due to isolation"),
ProgressReport { .. } =>
format!("progress report: current operation being executed is here"),
Int2Ptr { .. } =>
format!("integer-to-pointer cast"),
WeakMemoryOutdatedLoad =>
format!("weak memory emulation: outdated value returned from load"),
};
let notes = match e {
ProgressReport { block_count } => {
vec![
(None, format!("so far, {block_count} basic blocks have been executed")),
]
}
_ => vec![],
};
let helps = match e {
Int2Ptr { details: true } =>
vec![
(None, format!("This program is using integer-to-pointer casts or (equivalently) `ptr::from_exposed_addr`,")),
(None, format!("which means that Miri might miss pointer bugs in this program.")),
(None, format!("See https://doc.rust-lang.org/nightly/std/ptr/fn.from_exposed_addr.html for more details on that operation.")),
(None, format!("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.")),
(None, format!("You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `from_exposed_addr` semantics.")),
(None, format!("Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning.")),
],
_ => vec![],
};
report_msg(this, diag_level, title, vec![msg], notes, helps, &stacktrace);
}
});
}
fn handle_ice(&self) {
eprintln!();
eprintln!(
"Miri caused an ICE during evaluation. Here's the interpreter backtrace at the time of the panic:"
);
let this = self.eval_context_ref();
let stacktrace = this.generate_stacktrace();
report_msg(
this,
DiagLevel::Note,
"the place in the program where the ICE was triggered",
vec![],
vec![],
vec![],
&stacktrace,
);
}
}