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Don't ICE on unnormalized struct tail in layout computation

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This commit is contained in:
Michael Goulet 2023-06-19 19:57:44 +00:00
parent 3b2073f076
commit dd620aa73a
6 changed files with 65 additions and 12 deletions
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8
compiler/rustc_middle/src/ty/layout.rs
View file

@ -318,7 +318,13 @@ pub fn compute(
Ok(layout) => {
return Ok(SizeSkeleton::Known(layout.size));
}
Err(err) => err,
Err(err @ LayoutError::Unknown(_)) => err,
// We can't extract SizeSkeleton info from other layout errors
Err(
e @ LayoutError::Cycle
| e @ LayoutError::SizeOverflow(_)
| e @ LayoutError::NormalizationFailure(..),
) => return Err(e),
};
match *ty.kind() {

20
compiler/rustc_ty_utils/src/layout.rs
View file

@ -145,17 +145,20 @@ fn layout_of_uncached<'tcx>(
return Ok(tcx.mk_layout(LayoutS::scalar(cx, data_ptr)));
}
let unsized_part = tcx.struct_tail_erasing_lifetimes(pointee, param_env);
let metadata = if let Some(metadata_def_id) = tcx.lang_items().metadata_type()
// Projection eagerly bails out when the pointee references errors,
// fall back to structurally deducing metadata.
&& !pointee.references_error()
{
let metadata_ty = tcx.normalize_erasing_regions(
let pointee_metadata = tcx.mk_projection(metadata_def_id, [pointee]);
let metadata_ty = match tcx.try_normalize_erasing_regions(
param_env,
tcx.mk_projection(metadata_def_id, [pointee]),
);
pointee_metadata,
) {
Ok(metadata_ty) => metadata_ty,
Err(err) => return Err(LayoutError::NormalizationFailure(pointee, err)),
};
let metadata_layout = cx.layout_of(metadata_ty)?;
// If the metadata is a 1-zst, then the pointer is thin.
if metadata_layout.is_zst() && metadata_layout.align.abi.bytes() == 1 {
@ -163,10 +166,13 @@ fn layout_of_uncached<'tcx>(
}
let Abi::Scalar(metadata) = metadata_layout.abi else {
return Err(LayoutError::Unknown(unsized_part));
return Err(LayoutError::Unknown(pointee));
};
metadata
} else {
let unsized_part = tcx.struct_tail_erasing_lifetimes(pointee, param_env);
match unsized_part.kind() {
ty::Foreign(..) => {
return Ok(tcx.mk_layout(LayoutS::scalar(cx, data_ptr)));
@ -178,7 +184,7 @@ fn layout_of_uncached<'tcx>(
vtable
}
_ => {
return Err(LayoutError::Unknown(unsized_part));
return Err(LayoutError::Unknown(pointee));
}
}
};

4
tests/ui/const-generics/issue-112505-overflow.stderr
View file

@ -4,8 +4,8 @@ error[E0512]: cannot transmute between types of different sizes, or dependently-
LL | unsafe { std::mem::transmute(v) }
| ^^^^^^^^^^^^^^^^^^^
|
= note: source type: `[[[u32; 8888888]; 9999999]; 777777777]` (values of the type `[[[u32; 8888888]; 9999999]; 777777777]` are too big for the current architecture)
= note: target type: `[[[u32; 9999999]; 777777777]; 239]` (59484438436515561504 bits)
= note: source type: `[[[u32; 8888888]; 9999999]; 777777777]` (values of the type `[[u32; 8888888]; 9999999]` are too big for the current architecture)
= note: target type: `[[[u32; 9999999]; 777777777]; 239]` (values of the type `[[u32; 9999999]; 777777777]` are too big for the current architecture)
error: aborting due to previous error

4
tests/ui/const-generics/transmute-fail.stderr
View file

@ -43,8 +43,8 @@ error[E0512]: cannot transmute between types of different sizes, or dependently-
LL | std::mem::transmute(v)
| ^^^^^^^^^^^^^^^^^^^
|
= note: source type: `[[[u32; 8888888]; 9999999]; 777777777]` (values of the type `[[[u32; 8888888]; 9999999]; 777777777]` are too big for the current architecture)
= note: target type: `[[[u32; 9999999]; 777777777]; 8888888]` (values of the type `[[[u32; 9999999]; 777777777]; 8888888]` are too big for the current architecture)
= note: source type: `[[[u32; 8888888]; 9999999]; 777777777]` (values of the type `[[u32; 8888888]; 9999999]` are too big for the current architecture)
= note: target type: `[[[u32; 9999999]; 777777777]; 8888888]` (values of the type `[[u32; 9999999]; 777777777]` are too big for the current architecture)
error: aborting due to 6 previous errors

22
tests/ui/layout/cannot-transmute-unnormalizable-type.rs Normal file
View file

@ -0,0 +1,22 @@
trait Trait {
type RefTarget;
}
impl Trait for ()
where
Missing: Trait,
//~^ ERROR cannot find type `Missing` in this scope
{
type RefTarget = ();
}
struct Other {
data: <() as Trait>::RefTarget,
}
fn main() {
unsafe {
std::mem::transmute::<Option<()>, Option<&Other>>(None);
//~^ ERROR cannot transmute between types of different sizes, or dependently-sized types
}
}

19
tests/ui/layout/cannot-transmute-unnormalizable-type.stderr Normal file
View file

@ -0,0 +1,19 @@
error[E0412]: cannot find type `Missing` in this scope
--> $DIR/cannot-transmute-unnormalizable-type.rs:7:5
|
LL | Missing: Trait,
| ^^^^^^^ not found in this scope
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
--> $DIR/cannot-transmute-unnormalizable-type.rs:19:9
|
LL | std::mem::transmute::<Option<()>, Option<&Other>>(None);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: source type: `Option<()>` (8 bits)
= note: target type: `Option<&Other>` (unable to determine layout for `Other` because `<Other as Pointee>::Metadata` cannot be normalized)
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0412, E0512.
For more information about an error, try `rustc --explain E0412`.