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Rollup merge of #126833 - RalfJung:extern-type-field-ice, r=compiler-errors

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don't ICE when encountering an extern type field during validation

"extern type" is a pain that keeps on giving...

Fixes https://github.com/rust-lang/rust/issues/126814

r? ```@oli-obk```
This commit is contained in:
Matthias Krüger 2024-06-23 22:39:00 +02:00 committed by GitHub
commit a9959bd1ab
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GPG Key ID: B5690EEEBB952194
15 changed files with 97 additions and 82 deletions
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2
compiler/rustc_const_eval/messages.ftl
View File

@ -89,6 +89,8 @@ const_eval_exact_div_has_remainder =
const_eval_extern_static =
cannot access extern static ({$did})
const_eval_extern_type_field = `extern type` field does not have a known offset
const_eval_fn_ptr_call =
function pointers need an RFC before allowed to be called in {const_eval_const_context}s
const_eval_for_loop_into_iter_non_const =

78
compiler/rustc_const_eval/src/const_eval/eval_queries.rs
View File

@ -386,33 +386,8 @@ fn eval_in_interpreter<'tcx, R: InterpretationResult<'tcx>>(
CompileTimeMachine::new(CanAccessMutGlobal::from(is_static), CheckAlignment::Error),
);
let res = ecx.load_mir(cid.instance.def, cid.promoted);
res.and_then(|body| eval_body_using_ecx(&mut ecx, cid, body)).map_err(|error| {
let (error, backtrace) = error.into_parts();
backtrace.print_backtrace();
let (kind, instance) = if ecx.tcx.is_static(cid.instance.def_id()) {
("static", String::new())
} else {
// If the current item has generics, we'd like to enrich the message with the
// instance and its args: to show the actual compile-time values, in addition to
// the expression, leading to the const eval error.
let instance = &cid.instance;
if !instance.args.is_empty() {
let instance = with_no_trimmed_paths!(instance.to_string());
("const_with_path", instance)
} else {
("const", String::new())
}
};
super::report(
*ecx.tcx,
error,
DUMMY_SP,
|| super::get_span_and_frames(ecx.tcx, ecx.stack()),
|span, frames| ConstEvalError { span, error_kind: kind, instance, frame_notes: frames },
)
})
res.and_then(|body| eval_body_using_ecx(&mut ecx, cid, body))
.map_err(|error| report_eval_error(&ecx, cid, error))
}
#[inline(always)]
@ -438,23 +413,60 @@ fn const_validate_mplace<'tcx>(
ecx.const_validate_operand(&mplace.into(), path, &mut ref_tracking, mode)
// Instead of just reporting the `InterpError` via the usual machinery, we give a more targeted
// error about the validation failure.
.map_err(|error| report_validation_error(&ecx, error, alloc_id))?;
.map_err(|error| report_validation_error(&ecx, cid, error, alloc_id))?;
inner = true;
}
Ok(())
}
#[inline(always)]
fn report_validation_error<'tcx>(
#[inline(never)]
fn report_eval_error<'tcx>(
ecx: &InterpCx<'tcx, CompileTimeMachine<'tcx>>,
cid: GlobalId<'tcx>,
error: InterpErrorInfo<'tcx>,
alloc_id: AllocId,
) -> ErrorHandled {
let (error, backtrace) = error.into_parts();
backtrace.print_backtrace();
let ub_note = matches!(error, InterpError::UndefinedBehavior(_)).then(|| {});
let (kind, instance) = if ecx.tcx.is_static(cid.instance.def_id()) {
("static", String::new())
} else {
// If the current item has generics, we'd like to enrich the message with the
// instance and its args: to show the actual compile-time values, in addition to
// the expression, leading to the const eval error.
let instance = &cid.instance;
if !instance.args.is_empty() {
let instance = with_no_trimmed_paths!(instance.to_string());
("const_with_path", instance)
} else {
("const", String::new())
}
};
super::report(
*ecx.tcx,
error,
DUMMY_SP,
|| super::get_span_and_frames(ecx.tcx, ecx.stack()),
|span, frames| ConstEvalError { span, error_kind: kind, instance, frame_notes: frames },
)
}
#[inline(never)]
fn report_validation_error<'tcx>(
ecx: &InterpCx<'tcx, CompileTimeMachine<'tcx>>,
cid: GlobalId<'tcx>,
error: InterpErrorInfo<'tcx>,
alloc_id: AllocId,
) -> ErrorHandled {
if !matches!(error.kind(), InterpError::UndefinedBehavior(_)) {
// Some other error happened during validation, e.g. an unsupported operation.
return report_eval_error(ecx, cid, error);
}
let (error, backtrace) = error.into_parts();
backtrace.print_backtrace();
let bytes = ecx.print_alloc_bytes_for_diagnostics(alloc_id);
let (size, align, _) = ecx.get_alloc_info(alloc_id);
@ -465,6 +477,6 @@ fn report_validation_error<'tcx>(
error,
DUMMY_SP,
|| crate::const_eval::get_span_and_frames(ecx.tcx, ecx.stack()),
move |span, frames| errors::ValidationFailure { span, ub_note, frames, raw_bytes },
move |span, frames| errors::ValidationFailure { span, ub_note: (), frames, raw_bytes },
)
}

8
compiler/rustc_const_eval/src/errors.rs
View File

@ -425,7 +425,7 @@ pub struct ValidationFailure {
#[primary_span]
pub span: Span,
#[note(const_eval_validation_failure_note)]
pub ub_note: Option<()>,
pub ub_note: (),
#[subdiagnostic]
pub frames: Vec<FrameNote>,
#[subdiagnostic]
@ -825,6 +825,7 @@ fn diagnostic_message(&self) -> DiagMessage {
use crate::fluent_generated::*;
match self {
UnsupportedOpInfo::Unsupported(s) => s.clone().into(),
UnsupportedOpInfo::ExternTypeField => const_eval_extern_type_field,
UnsupportedOpInfo::UnsizedLocal => const_eval_unsized_local,
UnsupportedOpInfo::OverwritePartialPointer(_) => const_eval_partial_pointer_overwrite,
UnsupportedOpInfo::ReadPartialPointer(_) => const_eval_partial_pointer_copy,
@ -845,7 +846,10 @@ fn add_args<G: EmissionGuarantee>(self, diag: &mut Diag<'_, G>) {
// `ReadPointerAsInt(Some(info))` is never printed anyway, it only serves as an error to
// be further processed by validity checking which then turns it into something nice to
// print. So it's not worth the effort of having diagnostics that can print the `info`.
UnsizedLocal | Unsupported(_) | ReadPointerAsInt(_) => {}
UnsizedLocal
| UnsupportedOpInfo::ExternTypeField
| Unsupported(_)
| ReadPointerAsInt(_) => {}
OverwritePartialPointer(ptr) | ReadPartialPointer(ptr) => {
diag.arg("ptr", ptr);
}

6
compiler/rustc_const_eval/src/interpret/projection.rs
View File

@ -21,7 +21,7 @@
use tracing::{debug, instrument};
use super::{
throw_ub, throw_unsup_format, InterpCx, InterpResult, MPlaceTy, Machine, MemPlaceMeta, OpTy,
throw_ub, throw_unsup, InterpCx, InterpResult, MPlaceTy, Machine, MemPlaceMeta, OpTy,
Provenance, Scalar,
};
@ -186,8 +186,8 @@ pub fn project_field<P: Projectable<'tcx, M::Provenance>>(
(base_meta, offset)
}
None => {
// We don't know the alignment of this field, so we cannot adjust.
throw_unsup_format!("`extern type` does not have a known offset")
// We cannot know the alignment of this field, so we cannot adjust.
throw_unsup!(ExternTypeField)
}
}
} else {

10
compiler/rustc_const_eval/src/interpret/validity.rs
View File

@ -5,6 +5,7 @@
//! to be const-safe.
use std::fmt::Write;
use std::hash::Hash;
use std::num::NonZero;
use either::{Left, Right};
@ -17,7 +18,8 @@
use rustc_middle::bug;
use rustc_middle::mir::interpret::{
ExpectedKind, InterpError, InvalidMetaKind, Misalignment, PointerKind, Provenance,
ValidationErrorInfo, ValidationErrorKind, ValidationErrorKind::*,
UnsupportedOpInfo, ValidationErrorInfo,
ValidationErrorKind::{self, *},
};
use rustc_middle::ty::layout::{LayoutOf, TyAndLayout};
use rustc_middle::ty::{self, Ty};
@ -26,8 +28,6 @@
Abi, FieldIdx, Scalar as ScalarAbi, Size, VariantIdx, Variants, WrappingRange,
};
use std::hash::Hash;
use super::{
err_ub, format_interp_error, machine::AllocMap, throw_ub, AllocId, AllocKind, CheckInAllocMsg,
GlobalAlloc, ImmTy, Immediate, InterpCx, InterpResult, MPlaceTy, Machine, MemPlaceMeta, OpTy,
@ -1028,7 +1028,9 @@ fn validate_operand_internal(
Err(err)
if matches!(
err.kind(),
err_ub!(ValidationError { .. }) | InterpError::InvalidProgram(_)
err_ub!(ValidationError { .. })
| InterpError::InvalidProgram(_)
| InterpError::Unsupported(UnsupportedOpInfo::ExternTypeField)
) =>
{
Err(err)

2
compiler/rustc_middle/src/mir/interpret/error.rs
View File

@ -520,6 +520,8 @@ pub enum UnsupportedOpInfo {
Unsupported(String),
/// Unsized local variables.
UnsizedLocal,
/// Extern type field with an indeterminate offset.
ExternTypeField,
//
// The variants below are only reachable from CTFE/const prop, miri will never emit them.
//

4
src/tools/miri/src/diagnostics.rs
View File

@ -311,7 +311,9 @@ pub fn report_error<'tcx>(
ResourceExhaustion(_) => "resource exhaustion",
Unsupported(
// We list only the ones that can actually happen.
UnsupportedOpInfo::Unsupported(_) | UnsupportedOpInfo::UnsizedLocal,
UnsupportedOpInfo::Unsupported(_)
| UnsupportedOpInfo::UnsizedLocal
| UnsupportedOpInfo::ExternTypeField,
) => "unsupported operation",
InvalidProgram(
// We list only the ones that can actually happen.

4
src/tools/miri/tests/fail/extern-type-field-offset.stderr
View File

@ -1,8 +1,8 @@
error: unsupported operation: `extern type` does not have a known offset
error: unsupported operation: `extern type` field does not have a known offset
--> $DIR/extern-type-field-offset.rs:LL:CC
|
LL | let _field = &x.a;
| ^^^^ `extern type` does not have a known offset
| ^^^^ `extern type` field does not have a known offset
|
= help: this is likely not a bug in the program; it indicates that the program performed an operation that Miri does not support
= note: BACKTRACE:

2
tests/ui/consts/const-eval/issue-91827-extern-types-field-offset.stderr
View File

@ -2,7 +2,7 @@ error[E0080]: evaluation of constant value failed
--> $DIR/issue-91827-extern-types-field-offset.rs:38:17
|
LL | let field = &x.a;
| ^^^^ `extern type` does not have a known offset
| ^^^^ `extern type` field does not have a known offset
error: aborting due to 1 previous error

15
tests/ui/consts/const-eval/validation-ice-extern-type-field.rs Normal file
View File

@ -0,0 +1,15 @@
#![feature(extern_types)]
extern {
type Opaque;
}
struct ThinDst {
x: u8,
tail: Opaque,
}
const C1: &ThinDst = unsafe { std::mem::transmute(b"d".as_ptr()) };
//~^ERROR: evaluation of constant value failed
fn main() {}

9
tests/ui/consts/const-eval/validation-ice-extern-type-field.stderr Normal file
View File

@ -0,0 +1,9 @@
error[E0080]: evaluation of constant value failed
--> $DIR/validation-ice-extern-type-field.rs:12:1
|
LL | const C1: &ThinDst = unsafe { std::mem::transmute(b"d".as_ptr()) };
| ^^^^^^^^^^^^^^^^^^ `extern type` field does not have a known offset
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0080`.

6
tests/ui/sized/stack-overflow-trait-infer-98842.32bit.stderr
View File

@ -9,15 +9,11 @@ LL | const _: *const Foo = 0 as _;
| ^^^^^^^^^^^^^^^^^^^
= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
error[E0080]: it is undefined behavior to use this value
error[E0080]: evaluation of constant value failed
--> $DIR/stack-overflow-trait-infer-98842.rs:15:1
|
LL | const _: *const Foo = 0 as _;
| ^^^^^^^^^^^^^^^^^^^ a cycle occurred during layout computation
|
= note: the raw bytes of the constant (size: 4, align: 4) {
00 00 00 00 │ ....
}
error: aborting due to 2 previous errors

6
tests/ui/sized/stack-overflow-trait-infer-98842.64bit.stderr
View File

@ -9,15 +9,11 @@ LL | const _: *const Foo = 0 as _;
| ^^^^^^^^^^^^^^^^^^^
= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
error[E0080]: it is undefined behavior to use this value
error[E0080]: evaluation of constant value failed
--> $DIR/stack-overflow-trait-infer-98842.rs:15:1
|
LL | const _: *const Foo = 0 as _;
| ^^^^^^^^^^^^^^^^^^^ a cycle occurred during layout computation
|
= note: the raw bytes of the constant (size: 8, align: 8) {
00 00 00 00 00 00 00 00 │ ........
}
error: aborting due to 2 previous errors

2
tests/ui/sized/stack-overflow-trait-infer-98842.rs
View File

@ -13,6 +13,6 @@
// and it will infinitely recurse somewhere trying to figure out the
// size of this pointer (is my guess):
const _: *const Foo = 0 as _;
//~^ ERROR it is undefined behavior to use this value
//~^ ERROR evaluation of constant value failed
pub fn main() {}

25
tests/ui/sized/stack-overflow-trait-infer-98842.stderr
View File

@ -1,25 +0,0 @@
error[E0391]: cycle detected when computing layout of `Foo`
|
= note: ...which requires computing layout of `<&'static Foo as core::ops::deref::Deref>::Target`...
= note: ...which again requires computing layout of `Foo`, completing the cycle
note: cycle used when const-evaluating + checking `_`
--> $DIR/stack-overflow-trait-infer-98842.rs:13:1
|
LL | const _: *const Foo = 0 as _;
| ^^^^^^^^^^^^^^^^^^^
= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
error[E0080]: it is undefined behavior to use this value
--> $DIR/stack-overflow-trait-infer-98842.rs:13:1
|
LL | const _: *const Foo = 0 as _;
| ^^^^^^^^^^^^^^^^^^^ a cycle occurred during layout computation
|
= note: the raw bytes of the constant (size: 8, align: 8) {
00 00 00 00 00 00 00 00 │ ........
}
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0080, E0391.
For more information about an error, try `rustc --explain E0080`.