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matthiaskrgrmatthiaskrgr
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Rollup merge of #129364 - jswrenn:transmute-layout-errs, r=compiler-errors
safe transmute: gracefully bubble-up layout errors Changes `.unwrap()`s to `?` to avoid ICEs. Adds ui tests. Fixes #129327 Tracking Issue: #99571 r​? `@compiler-errors`
2 parents 92f0b7e + e2328eb commit 00e109f

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9 files changed

+121
-49
lines changed

9 files changed

+121
-49
lines changed

‎compiler/rustc_transmute/src/layout/tree.rs‎

Lines changed: 7 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -179,7 +179,7 @@ pub(crate) mod rustc {
179179
};
180180

181181
use super::Tree;
182-
use crate::layout::rustc::{Def, Ref};
182+
use crate::layout::rustc::{layout_of, Def, Ref};
183183

184184
#[derive(Debug, Copy, Clone)]
185185
pub(crate) enum Err {
@@ -206,7 +206,7 @@ pub(crate) mod rustc {
206206
impl<'tcx> Tree<Def<'tcx>, Ref<'tcx>> {
207207
pub fn from_ty(ty: Ty<'tcx>, cx: LayoutCx<'tcx, TyCtxt<'tcx>>) -> Result<Self, Err> {
208208
use rustc_target::abi::HasDataLayout;
209-
let layout = ty_layout(cx, ty);
209+
let layout = layout_of(cx, ty)?;
210210

211211
if let Err(e) = ty.error_reported() {
212212
return Err(Err::TypeError(e));
@@ -239,7 +239,7 @@ pub(crate) mod rustc {
239239
let FieldsShape::Array { stride, count } = &layout.fields else {
240240
return Err(Err::NotYetSupported);
241241
};
242-
let inner_layout = ty_layout(cx, *inner_ty);
242+
let inner_layout = layout_of(cx, *inner_ty)?;
243243
assert_eq!(*stride, inner_layout.size);
244244
let elt = Tree::from_ty(*inner_ty, cx)?;
245245
Ok(std::iter::repeat(elt)
@@ -254,7 +254,7 @@ pub(crate) mod rustc {
254254
},
255255

256256
ty::Ref(lifetime, ty, mutability) => {
257-
let layout = ty_layout(cx, *ty);
257+
let layout = layout_of(cx, *ty)?;
258258
let align = layout.align.abi.bytes_usize();
259259
let size = layout.size.bytes_usize();
260260
Ok(Tree::Ref(Ref {
@@ -280,7 +280,7 @@ pub(crate) mod rustc {
280280
FieldsShape::Primitive => {
281281
assert_eq!(members.len(), 1);
282282
let inner_ty = members[0];
283-
let inner_layout = ty_layout(cx, inner_ty);
283+
let inner_layout = layout_of(cx, inner_ty)?;
284284
Self::from_ty(inner_ty, cx)
285285
}
286286
FieldsShape::Arbitrary { offsets, .. } => {
@@ -413,7 +413,7 @@ pub(crate) mod rustc {
413413
let padding = Self::padding(padding_needed.bytes_usize());
414414

415415
let field_ty = ty_field(cx, (ty, layout), field_idx);
416-
let field_layout = ty_layout(cx, field_ty);
416+
let field_layout = layout_of(cx, field_ty)?;
417417
let field_tree = Self::from_ty(field_ty, cx)?;
418418

419419
struct_tree = struct_tree.then(padding).then(field_tree);
@@ -471,7 +471,7 @@ pub(crate) mod rustc {
471471
|fields, (idx, field_def)| {
472472
let field_def = Def::Field(field_def);
473473
let field_ty = ty_field(cx, (ty, layout), idx);
474-
let field_layout = ty_layout(cx, field_ty);
474+
let field_layout = layout_of(cx, field_ty)?;
475475
let field = Self::from_ty(field_ty, cx)?;
476476
let trailing_padding_needed = layout.size - field_layout.size;
477477
let trailing_padding = Self::padding(trailing_padding_needed.bytes_usize());
@@ -484,10 +484,6 @@ pub(crate) mod rustc {
484484
}
485485
}
486486

487-
pub(crate) fn ty_layout<'tcx>(cx: LayoutCx<'tcx, TyCtxt<'tcx>>, ty: Ty<'tcx>) -> Layout<'tcx> {
488-
crate::layout::rustc::layout_of(cx, ty).unwrap()
489-
}
490-
491487
fn ty_field<'tcx>(
492488
cx: LayoutCx<'tcx, TyCtxt<'tcx>>,
493489
(ty, layout): (Ty<'tcx>, Layout<'tcx>),

‎compiler/rustc_transmute/src/maybe_transmutable/mod.rs‎

Lines changed: 3 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -44,18 +44,11 @@ mod rustc {
4444
let Self { src, dst, assume, context } = self;
4545

4646
let layout_cx = LayoutCx { tcx: context, param_env: ParamEnv::reveal_all() };
47-
let layout_of = |ty| {
48-
crate::layout::rustc::layout_of(layout_cx, ty)
49-
.map_err(|_| Err::NotYetSupported)
50-
.and_then(|_| Tree::from_ty(ty, layout_cx))
51-
};
5247

5348
// Convert `src` and `dst` from their rustc representations, to `Tree`-based
54-
// representations. If these conversions fail, conclude that the transmutation is
55-
// unacceptable; the layouts of both the source and destination types must be
56-
// well-defined.
57-
let src = layout_of(src);
58-
let dst = layout_of(dst);
49+
// representations.
50+
let src = Tree::from_ty(src, layout_cx);
51+
let dst = Tree::from_ty(dst, layout_cx);
5952

6053
match (src, dst) {
6154
(Err(Err::TypeError(_)), _) | (_, Err(Err::TypeError(_))) => {

‎tests/ui/transmutability/arrays/huge-len.stderr‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,7 @@ error[E0277]: `()` cannot be safely transmuted into `ExplicitlyPadded`
22
--> $DIR/huge-len.rs:21:41
33
|
44
LL | assert::is_maybe_transmutable::<(), ExplicitlyPadded>();
5-
| ^^^^^^^^^^^^^^^^ analyzing the transmutability of `ExplicitlyPadded` is not yet supported
5+
| ^^^^^^^^^^^^^^^^ values of the type `ExplicitlyPadded` are too big for the current architecture
66
|
77
note: required by a bound in `is_maybe_transmutable`
88
--> $DIR/huge-len.rs:8:14
@@ -17,7 +17,7 @@ error[E0277]: `ExplicitlyPadded` cannot be safely transmuted into `()`
1717
--> $DIR/huge-len.rs:24:55
1818
|
1919
LL | assert::is_maybe_transmutable::<ExplicitlyPadded, ()>();
20-
| ^^ analyzing the transmutability of `ExplicitlyPadded` is not yet supported
20+
| ^^ values of the type `ExplicitlyPadded` are too big for the current architecture
2121
|
2222
note: required by a bound in `is_maybe_transmutable`
2323
--> $DIR/huge-len.rs:8:14

‎tests/ui/transmutability/malformed-program-gracefulness/unknown_dst_field.rs‎

Lines changed: 26 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,26 @@
1+
// An unknown destination type should be gracefully handled.
2+
3+
#![crate_type = "lib"]
4+
#![feature(transmutability)]
5+
#![allow(incomplete_features)]
6+
7+
mod assert {
8+
use std::mem::BikeshedIntrinsicFrom;
9+
10+
pub fn is_transmutable<Src, Dst>()
11+
where
12+
Dst: BikeshedIntrinsicFrom<Src>
13+
{}
14+
}
15+
16+
fn should_gracefully_handle_unknown_dst_field() {
17+
#[repr(C)] struct Src;
18+
#[repr(C)] struct Dst(Missing); //~ cannot find type
19+
assert::is_transmutable::<Src, Dst>(); //~ ERROR cannot be safely transmuted
20+
}
21+
22+
fn should_gracefully_handle_unknown_dst_ref_field() {
23+
#[repr(C)] struct Src(&'static Src);
24+
#[repr(C)] struct Dst(&'static Missing); //~ cannot find type
25+
assert::is_transmutable::<Src, Dst>(); //~ ERROR cannot be safely transmuted
26+
}

‎tests/ui/transmutability/malformed-program-gracefulness/unknown_dst_field.stderr‎

Lines changed: 46 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,46 @@
1+
error[E0412]: cannot find type `Missing` in this scope
2+
--> $DIR/unknown_dst_field.rs:18:27
3+
|
4+
LL | #[repr(C)] struct Dst(Missing);
5+
| ^^^^^^^ not found in this scope
6+
7+
error[E0412]: cannot find type `Missing` in this scope
8+
--> $DIR/unknown_dst_field.rs:24:36
9+
|
10+
LL | #[repr(C)] struct Dst(&'static Missing);
11+
| ^^^^^^^ not found in this scope
12+
13+
error[E0277]: `should_gracefully_handle_unknown_dst_field::Src` cannot be safely transmuted into `should_gracefully_handle_unknown_dst_field::Dst`
14+
--> $DIR/unknown_dst_field.rs:19:36
15+
|
16+
LL | assert::is_transmutable::<Src, Dst>();
17+
| ^^^ `should_gracefully_handle_unknown_dst_field::Dst` has an unknown layout
18+
|
19+
note: required by a bound in `is_transmutable`
20+
--> $DIR/unknown_dst_field.rs:12:14
21+
|
22+
LL | pub fn is_transmutable<Src, Dst>()
23+
| --------------- required by a bound in this function
24+
LL | where
25+
LL | Dst: BikeshedIntrinsicFrom<Src>
26+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
27+
28+
error[E0277]: `should_gracefully_handle_unknown_dst_ref_field::Src` cannot be safely transmuted into `should_gracefully_handle_unknown_dst_ref_field::Dst`
29+
--> $DIR/unknown_dst_field.rs:25:36
30+
|
31+
LL | assert::is_transmutable::<Src, Dst>();
32+
| ^^^ `should_gracefully_handle_unknown_dst_ref_field::Dst` has an unknown layout
33+
|
34+
note: required by a bound in `is_transmutable`
35+
--> $DIR/unknown_dst_field.rs:12:14
36+
|
37+
LL | pub fn is_transmutable<Src, Dst>()
38+
| --------------- required by a bound in this function
39+
LL | where
40+
LL | Dst: BikeshedIntrinsicFrom<Src>
41+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
42+
43+
error: aborting due to 4 previous errors
44+
45+
Some errors have detailed explanations: E0277, E0412.
46+
For more information about an error, try `rustc --explain E0277`.

‎tests/ui/transmutability/malformed-program-gracefulness/unknown_src_field.rs‎

Lines changed: 9 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -13,8 +13,14 @@ mod assert {
1313
{}
1414
}
1515

16-
fn should_gracefully_handle_unknown_dst_field() {
17-
#[repr(C)] struct Src;
18-
#[repr(C)] struct Dst(Missing); //~ cannot find type
16+
fn should_gracefully_handle_unknown_src_field() {
17+
#[repr(C)] struct Src(Missing); //~ cannot find type
18+
#[repr(C)] struct Dst();
19+
assert::is_transmutable::<Src, Dst>(); //~ ERROR cannot be safely transmuted
20+
}
21+
22+
fn should_gracefully_handle_unknown_src_ref_field() {
23+
#[repr(C)] struct Src(&'static Missing); //~ cannot find type
24+
#[repr(C)] struct Dst(&'static Dst);
1925
assert::is_transmutable::<Src, Dst>(); //~ ERROR cannot be safely transmuted
2026
}

‎tests/ui/transmutability/malformed-program-gracefulness/unknown_src_field.stderr‎

Lines changed: 26 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,14 +1,35 @@
11
error[E0412]: cannot find type `Missing` in this scope
2-
--> $DIR/unknown_src_field.rs:18:27
2+
--> $DIR/unknown_src_field.rs:17:27
33
|
4-
LL | #[repr(C)] struct Dst(Missing);
4+
LL | #[repr(C)] struct Src(Missing);
55
| ^^^^^^^ not found in this scope
66

7-
error[E0277]: `Src` cannot be safely transmuted into `Dst`
7+
error[E0412]: cannot find type `Missing` in this scope
8+
--> $DIR/unknown_src_field.rs:23:36
9+
|
10+
LL | #[repr(C)] struct Src(&'static Missing);
11+
| ^^^^^^^ not found in this scope
12+
13+
error[E0277]: `should_gracefully_handle_unknown_src_field::Src` cannot be safely transmuted into `should_gracefully_handle_unknown_src_field::Dst`
814
--> $DIR/unknown_src_field.rs:19:36
915
|
1016
LL | assert::is_transmutable::<Src, Dst>();
11-
| ^^^ analyzing the transmutability of `Dst` is not yet supported
17+
| ^^^ `should_gracefully_handle_unknown_src_field::Src` has an unknown layout
18+
|
19+
note: required by a bound in `is_transmutable`
20+
--> $DIR/unknown_src_field.rs:12:14
21+
|
22+
LL | pub fn is_transmutable<Src, Dst>()
23+
| --------------- required by a bound in this function
24+
LL | where
25+
LL | Dst: BikeshedIntrinsicFrom<Src>
26+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
27+
28+
error[E0277]: `should_gracefully_handle_unknown_src_ref_field::Src` cannot be safely transmuted into `should_gracefully_handle_unknown_src_ref_field::Dst`
29+
--> $DIR/unknown_src_field.rs:25:36
30+
|
31+
LL | assert::is_transmutable::<Src, Dst>();
32+
| ^^^ `should_gracefully_handle_unknown_src_ref_field::Src` has an unknown layout
1233
|
1334
note: required by a bound in `is_transmutable`
1435
--> $DIR/unknown_src_field.rs:12:14
@@ -19,7 +40,7 @@ LL | where
1940
LL | Dst: BikeshedIntrinsicFrom<Src>
2041
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
2142

22-
error: aborting due to 2 previous errors
43+
error: aborting due to 4 previous errors
2344

2445
Some errors have detailed explanations: E0277, E0412.
2546
For more information about an error, try `rustc --explain E0277`.

‎tests/ui/transmutability/structs/repr/transmute_infinitely_recursive_type.rs‎

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -22,5 +22,4 @@ fn should_pad_explicitly_packed_field() {
2222
//~^ ERROR: recursive type
2323

2424
assert::is_maybe_transmutable::<ExplicitlyPadded, ()>();
25-
//~^ ERROR: cannot be safely transmuted
2625
}

‎tests/ui/transmutability/structs/repr/transmute_infinitely_recursive_type.stderr‎

Lines changed: 2 additions & 17 deletions
Original file line numberDiff line numberDiff line change
@@ -15,22 +15,7 @@ error[E0391]: cycle detected when computing layout of `should_pad_explicitly_pac
1515
= note: cycle used when evaluating trait selection obligation `(): core::mem::transmutability::BikeshedIntrinsicFrom<should_pad_explicitly_packed_field::ExplicitlyPadded, core::mem::transmutability::Assume { alignment: false, lifetimes: false, safety: false, validity: false }>`
1616
= 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
1717

18-
error[E0277]: `ExplicitlyPadded` cannot be safely transmuted into `()`
19-
--> $DIR/transmute_infinitely_recursive_type.rs:24:55
20-
|
21-
LL | assert::is_maybe_transmutable::<ExplicitlyPadded, ()>();
22-
| ^^ analyzing the transmutability of `ExplicitlyPadded` is not yet supported
23-
|
24-
note: required by a bound in `is_maybe_transmutable`
25-
--> $DIR/transmute_infinitely_recursive_type.rs:14:14
26-
|
27-
LL | pub fn is_maybe_transmutable<Src, Dst>()
28-
| --------------------- required by a bound in this function
29-
LL | where
30-
LL | Dst: BikeshedIntrinsicFrom<Src>,
31-
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
32-
33-
error: aborting due to 3 previous errors
18+
error: aborting due to 2 previous errors
3419

35-
Some errors have detailed explanations: E0072, E0277, E0391.
20+
Some errors have detailed explanations: E0072, E0391.
3621
For more information about an error, try `rustc --explain E0072`.

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