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interpret: do not ICE when a promoted fails with OOM
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RalfJung committed Nov 18, 2024
1 parent 3fb7e44 commit c697434
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Showing 6 changed files with 51 additions and 7 deletions.
9 changes: 8 additions & 1 deletion compiler/rustc_const_eval/src/const_eval/error.rs
Original file line number Diff line number Diff line change
Expand Up @@ -152,13 +152,20 @@ where
let span = span.substitute_dummy(our_span);
let err = mk(span, frames);
let mut err = tcx.dcx().create_err(err);
let can_be_spurious = matches!(error, InterpErrorKind::ResourceExhaustion(_));

let msg = error.diagnostic_message();
error.add_args(&mut err);

// Use *our* span to label the interp error
err.span_label(our_span, msg);
ErrorHandled::Reported(err.emit().into(), span)
let g = err.emit();
let reported = if can_be_spurious {
ReportedErrorInfo::spurious(g)
} else {
ReportedErrorInfo::from(g)
};
ErrorHandled::Reported(reported, span)
}
}
}
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3 changes: 3 additions & 0 deletions compiler/rustc_const_eval/src/interpret/eval_context.rs
Original file line number Diff line number Diff line change
Expand Up @@ -596,6 +596,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
// const-eval will return "tainted" errors if e.g. the layout cannot
// be computed as the type references non-existing names.
// See <https://github.com/rust-lang/rust/issues/124348>.
} else if reported.can_be_spurious() {
// These errors can just sometimes happen, even when the expression
// is nominally "infallible", e.g. when running out of memory.
} else {
// Looks like the const is not captured by `required_consts`, that's bad.
span_bug!(span, "interpret const eval failure of {val:?} which is not in required_consts");
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15 changes: 13 additions & 2 deletions compiler/rustc_middle/src/mir/interpret/error.rs
Original file line number Diff line number Diff line change
Expand Up @@ -59,22 +59,33 @@ impl ErrorHandled {
pub struct ReportedErrorInfo {
error: ErrorGuaranteed,
is_tainted_by_errors: bool,
/// Whether this is the kind of error that can sometimes occur, and sometimes not.
/// Used for resource exhaustion errors.
can_be_spurious: bool,
}

impl ReportedErrorInfo {
#[inline]
pub fn tainted_by_errors(error: ErrorGuaranteed) -> ReportedErrorInfo {
ReportedErrorInfo { is_tainted_by_errors: true, error }
ReportedErrorInfo { is_tainted_by_errors: true, can_be_spurious: false, error }
}
#[inline]
pub fn spurious(error: ErrorGuaranteed) -> ReportedErrorInfo {
ReportedErrorInfo { can_be_spurious: true, is_tainted_by_errors: false, error }
}

pub fn is_tainted_by_errors(&self) -> bool {
self.is_tainted_by_errors
}
pub fn can_be_spurious(&self) -> bool {
self.can_be_spurious
}
}

impl From<ErrorGuaranteed> for ReportedErrorInfo {
#[inline]
fn from(error: ErrorGuaranteed) -> ReportedErrorInfo {
ReportedErrorInfo { is_tainted_by_errors: false, error }
ReportedErrorInfo { is_tainted_by_errors: false, can_be_spurious: false, error }
}
}

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4 changes: 0 additions & 4 deletions tests/crashes/130687.rs

This file was deleted.

12 changes: 12 additions & 0 deletions tests/ui/consts/promoted_running_out_of_memory_issue-130687.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
//! Ensure we do not ICE when a promoted fails to evaluate due to running out of memory.
//! Also see <https://github.com/rust-lang/rust/issues/130687>.
// Needs the max type size to be much bigger than the RAM people typically have.
//@ only-64bit

pub struct Data([u8; (1 << 47) - 1]);
const _: &'static Data = &Data([0; (1 << 47) - 1]);
//~^ERROR: evaluation of constant value failed
//~| tried to allocate more memory than available to compiler

fn main() {}
15 changes: 15 additions & 0 deletions tests/ui/consts/promoted_running_out_of_memory_issue-130687.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
error[E0080]: evaluation of constant value failed
--> $DIR/promoted_running_out_of_memory_issue-130687.rs:8:32
|
LL | const _: &'static Data = &Data([0; (1 << 47) - 1]);
| ^^^^^^^^^^^^^^^^^^ tried to allocate more memory than available to compiler

note: erroneous constant encountered
--> $DIR/promoted_running_out_of_memory_issue-130687.rs:8:26
|
LL | const _: &'static Data = &Data([0; (1 << 47) - 1]);
| ^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0080`.

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