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oli-obkoli-obk
committedMar 21, 2024
Sorting arbitrary constants should not be done, as it relies on DefId ordering, which breaks incremental compilation.
1 parent e8717f2 commit a5b6985

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4 files changed

+164
-138
lines changed

4 files changed

+164
-138
lines changed
 

‎compiler/rustc_middle/src/ty/layout.rs

Lines changed: 3 additions & 64 deletions
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,7 @@ use crate::error::UnsupportedFnAbi;
22
use crate::middle::codegen_fn_attrs::CodegenFnAttrFlags;
33
use crate::query::TyCtxtAt;
44
use crate::ty::normalize_erasing_regions::NormalizationError;
5-
use crate::ty::{self, ConstKind, Ty, TyCtxt, TypeVisitableExt};
5+
use crate::ty::{self, Ty, TyCtxt, TypeVisitableExt};
66
use rustc_error_messages::DiagMessage;
77
use rustc_errors::{
88
Diag, DiagArgValue, DiagCtxt, Diagnostic, EmissionGuarantee, IntoDiagArg, Level,
@@ -356,21 +356,10 @@ impl<'tcx> SizeSkeleton<'tcx> {
356356
.ok_or_else(|| &*tcx.arena.alloc(LayoutError::SizeOverflow(ty)))?;
357357
return Ok(SizeSkeleton::Known(Size::from_bytes(size)));
358358
}
359-
let len = tcx.expand_abstract_consts(len);
360-
let prev = ty::Const::from_target_usize(tcx, s.bytes());
361-
let Some(gen_size) = mul_sorted_consts(tcx, param_env, len, prev) else {
362-
return Err(tcx.arena.alloc(LayoutError::SizeOverflow(ty)));
363-
};
364-
Ok(SizeSkeleton::Generic(gen_size))
359+
Err(tcx.arena.alloc(LayoutError::Unknown(ty)))
365360
}
366361
SizeSkeleton::Pointer { .. } => Err(err),
367-
SizeSkeleton::Generic(g) => {
368-
let len = tcx.expand_abstract_consts(len);
369-
let Some(gen_size) = mul_sorted_consts(tcx, param_env, len, g) else {
370-
return Err(tcx.arena.alloc(LayoutError::SizeOverflow(ty)));
371-
};
372-
Ok(SizeSkeleton::Generic(gen_size))
373-
}
362+
SizeSkeleton::Generic(_) => Err(tcx.arena.alloc(LayoutError::Unknown(ty))),
374363
}
375364
}
376365

@@ -468,56 +457,6 @@ impl<'tcx> SizeSkeleton<'tcx> {
468457
}
469458
}
470459

471-
/// When creating the layout for types with abstract consts in their size (i.e. [usize; 4 * N]),
472-
/// to ensure that they have a canonical order and can be compared directly we combine all
473-
/// constants, and sort the other terms. This allows comparison of expressions of sizes,
474-
/// allowing for things like transmuting between types that depend on generic consts.
475-
/// This returns `None` if multiplication of constants overflows.
476-
fn mul_sorted_consts<'tcx>(
477-
tcx: TyCtxt<'tcx>,
478-
param_env: ty::ParamEnv<'tcx>,
479-
a: ty::Const<'tcx>,
480-
b: ty::Const<'tcx>,
481-
) -> Option<ty::Const<'tcx>> {
482-
use crate::mir::BinOp::Mul;
483-
484-
let mut work = vec![a, b];
485-
let mut done = vec![];
486-
while let Some(n) = work.pop() {
487-
if let ConstKind::Expr(ty::Expr::Binop(Mul, l, r)) = n.kind() {
488-
work.push(l);
489-
work.push(r)
490-
} else {
491-
done.push(n);
492-
}
493-
}
494-
let mut k = 1;
495-
let mut overflow = false;
496-
done.retain(|c| {
497-
let Some(c) = c.try_eval_target_usize(tcx, param_env) else {
498-
return true;
499-
};
500-
let Some(next) = c.checked_mul(k) else {
501-
overflow = true;
502-
return false;
503-
};
504-
k = next;
505-
false
506-
});
507-
if overflow {
508-
return None;
509-
}
510-
if k != 1 {
511-
done.push(ty::Const::from_target_usize(tcx, k));
512-
} else if k == 0 {
513-
return Some(ty::Const::from_target_usize(tcx, 0));
514-
}
515-
done.sort_unstable();
516-
517-
// create a single tree from the buffer
518-
done.into_iter().reduce(|acc, n| ty::Const::new_expr(tcx, ty::Expr::Binop(Mul, n, acc), n.ty()))
519-
}
520-
521460
pub trait HasTyCtxt<'tcx>: HasDataLayout {
522461
fn tcx(&self) -> TyCtxt<'tcx>;
523462
}

‎tests/ui/const-generics/transmute-fail.rs

Lines changed: 75 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -32,4 +32,79 @@ fn overflow(v: [[[u32; 8888888]; 9999999]; 777777777]) -> [[[u32; 9999999]; 7777
3232
}
3333
}
3434

35+
fn transpose<const W: usize, const H: usize>(v: [[u32;H]; W]) -> [[u32; W]; H] {
36+
unsafe {
37+
std::mem::transmute(v)
38+
//~^ ERROR: cannot transmute between types of different sizes, or dependently-sized types
39+
}
40+
}
41+
42+
fn ident<const W: usize, const H: usize>(v: [[u32; H]; W]) -> [[u32; H]; W] {
43+
unsafe {
44+
std::mem::transmute(v)
45+
}
46+
}
47+
48+
fn flatten<const W: usize, const H: usize>(v: [[u32; H]; W]) -> [u32; W * H] {
49+
unsafe {
50+
std::mem::transmute(v)
51+
//~^ ERROR: cannot transmute between types of different sizes, or dependently-sized types
52+
}
53+
}
54+
55+
fn coagulate<const W: usize, const H: usize>(v: [u32; H*W]) -> [[u32; W];H] {
56+
unsafe {
57+
std::mem::transmute(v)
58+
//~^ ERROR: cannot transmute between types of different sizes, or dependently-sized types
59+
}
60+
}
61+
62+
fn flatten_3d<const W: usize, const H: usize, const D: usize>(
63+
v: [[[u32; D]; H]; W]
64+
) -> [u32; D * W * H] {
65+
unsafe {
66+
std::mem::transmute(v)
67+
//~^ ERROR: cannot transmute between types of different sizes, or dependently-sized types
68+
}
69+
}
70+
71+
fn flatten_somewhat<const W: usize, const H: usize, const D: usize>(
72+
v: [[[u32; D]; H]; W]
73+
) -> [[u32; D * W]; H] {
74+
unsafe {
75+
std::mem::transmute(v)
76+
//~^ ERROR: cannot transmute between types of different sizes, or dependently-sized types
77+
}
78+
}
79+
80+
fn known_size<const L: usize>(v: [u16; L]) -> [u8; L * 2] {
81+
unsafe {
82+
std::mem::transmute(v)
83+
//~^ ERROR: cannot transmute between types of different sizes, or dependently-sized types
84+
}
85+
}
86+
87+
fn condense_bytes<const L: usize>(v: [u8; L * 2]) -> [u16; L] {
88+
unsafe {
89+
std::mem::transmute(v)
90+
//~^ ERROR: cannot transmute between types of different sizes, or dependently-sized types
91+
}
92+
}
93+
94+
fn singleton_each<const L: usize>(v: [u8; L]) -> [[u8;1]; L] {
95+
unsafe {
96+
std::mem::transmute(v)
97+
//~^ ERROR: cannot transmute between types of different sizes, or dependently-sized types
98+
}
99+
}
100+
101+
fn transpose_with_const<const W: usize, const H: usize>(
102+
v: [[u32; 2 * H]; W + W]
103+
) -> [[u32; W + W]; 2 * H] {
104+
unsafe {
105+
std::mem::transmute(v)
106+
//~^ ERROR: cannot transmute between types of different sizes, or dependently-sized types
107+
}
108+
}
109+
35110
fn main() {}

‎tests/ui/const-generics/transmute-fail.stderr

Lines changed: 86 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -4,8 +4,8 @@ error[E0512]: cannot transmute between types of different sizes, or dependently-
44
LL | std::mem::transmute(v)
55
| ^^^^^^^^^^^^^^^^^^^
66
|
7-
= note: source type: `[[u32; H+1]; W]` (generic size (H + 1) * 4 * W)
8-
= note: target type: `[[u32; W+1]; H]` (generic size (W + 1) * 4 * H)
7+
= note: source type: `[[u32; H+1]; W]` (size can vary because of [u32; H+1])
8+
= note: target type: `[[u32; W+1]; H]` (size can vary because of [u32; W+1])
99

1010
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
1111
--> $DIR/transmute-fail.rs:16:5
@@ -22,8 +22,8 @@ error[E0512]: cannot transmute between types of different sizes, or dependently-
2222
LL | std::mem::transmute(v)
2323
| ^^^^^^^^^^^^^^^^^^^
2424
|
25-
= note: source type: `[[u32; H]; W]` (generic size 4 * H * W)
26-
= note: target type: `[u32; W * H * H]` (generic size 4 * H * H * W)
25+
= note: source type: `[[u32; H]; W]` (size can vary because of [u32; H])
26+
= note: target type: `[u32; W * H * H]` (this type does not have a fixed size)
2727

2828
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
2929
--> $DIR/transmute-fail.rs:30:5
@@ -34,6 +34,87 @@ LL | std::mem::transmute(v)
3434
= note: source type: `[[[u32; 8888888]; 9999999]; 777777777]` (values of the type `[[u32; 8888888]; 9999999]` are too big for the current architecture)
3535
= note: target type: `[[[u32; 9999999]; 777777777]; 8888888]` (values of the type `[[u32; 9999999]; 777777777]` are too big for the current architecture)
3636

37+
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
38+
--> $DIR/transmute-fail.rs:37:5
39+
|
40+
LL | std::mem::transmute(v)
41+
| ^^^^^^^^^^^^^^^^^^^
42+
|
43+
= note: source type: `[[u32; H]; W]` (size can vary because of [u32; H])
44+
= note: target type: `[[u32; W]; H]` (size can vary because of [u32; W])
45+
46+
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
47+
--> $DIR/transmute-fail.rs:50:5
48+
|
49+
LL | std::mem::transmute(v)
50+
| ^^^^^^^^^^^^^^^^^^^
51+
|
52+
= note: source type: `[[u32; H]; W]` (size can vary because of [u32; H])
53+
= note: target type: `[u32; W * H]` (this type does not have a fixed size)
54+
55+
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
56+
--> $DIR/transmute-fail.rs:57:5
57+
|
58+
LL | std::mem::transmute(v)
59+
| ^^^^^^^^^^^^^^^^^^^
60+
|
61+
= note: source type: `[u32; H*W]` (this type does not have a fixed size)
62+
= note: target type: `[[u32; W]; H]` (size can vary because of [u32; W])
63+
64+
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
65+
--> $DIR/transmute-fail.rs:66:5
66+
|
67+
LL | std::mem::transmute(v)
68+
| ^^^^^^^^^^^^^^^^^^^
69+
|
70+
= note: source type: `[[[u32; D]; H]; W]` (size can vary because of [u32; D])
71+
= note: target type: `[u32; D * W * H]` (this type does not have a fixed size)
72+
73+
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
74+
--> $DIR/transmute-fail.rs:75:5
75+
|
76+
LL | std::mem::transmute(v)
77+
| ^^^^^^^^^^^^^^^^^^^
78+
|
79+
= note: source type: `[[[u32; D]; H]; W]` (size can vary because of [u32; D])
80+
= note: target type: `[[u32; D * W]; H]` (size can vary because of [u32; D * W])
81+
82+
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
83+
--> $DIR/transmute-fail.rs:82:5
84+
|
85+
LL | std::mem::transmute(v)
86+
| ^^^^^^^^^^^^^^^^^^^
87+
|
88+
= note: source type: `[u16; L]` (this type does not have a fixed size)
89+
= note: target type: `[u8; L * 2]` (this type does not have a fixed size)
90+
91+
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
92+
--> $DIR/transmute-fail.rs:89:5
93+
|
94+
LL | std::mem::transmute(v)
95+
| ^^^^^^^^^^^^^^^^^^^
96+
|
97+
= note: source type: `[u8; L * 2]` (this type does not have a fixed size)
98+
= note: target type: `[u16; L]` (this type does not have a fixed size)
99+
100+
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
101+
--> $DIR/transmute-fail.rs:96:5
102+
|
103+
LL | std::mem::transmute(v)
104+
| ^^^^^^^^^^^^^^^^^^^
105+
|
106+
= note: source type: `[u8; L]` (this type does not have a fixed size)
107+
= note: target type: `[[u8; 1]; L]` (this type does not have a fixed size)
108+
109+
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
110+
--> $DIR/transmute-fail.rs:105:5
111+
|
112+
LL | std::mem::transmute(v)
113+
| ^^^^^^^^^^^^^^^^^^^
114+
|
115+
= note: source type: `[[u32; 2 * H]; W + W]` (size can vary because of [u32; 2 * H])
116+
= note: target type: `[[u32; W + W]; 2 * H]` (size can vary because of [u32; W + W])
117+
37118
error[E0308]: mismatched types
38119
--> $DIR/transmute-fail.rs:12:53
39120
|
@@ -46,7 +127,7 @@ error[E0308]: mismatched types
46127
LL | fn bar<const W: bool, const H: usize>(v: [[u32; H]; W]) -> [[u32; W]; H] {
47128
| ^ expected `usize`, found `bool`
48129

49-
error: aborting due to 6 previous errors
130+
error: aborting due to 15 previous errors
50131

51132
Some errors have detailed explanations: E0308, E0512.
52133
For more information about an error, try `rustc --explain E0308`.

‎tests/ui/const-generics/transmute.rs

Lines changed: 0 additions & 69 deletions
Original file line numberDiff line numberDiff line change
@@ -3,81 +3,12 @@
33
#![feature(transmute_generic_consts)]
44
#![allow(incomplete_features)]
55

6-
fn transpose<const W: usize, const H: usize>(v: [[u32;H]; W]) -> [[u32; W]; H] {
7-
unsafe {
8-
std::mem::transmute(v)
9-
}
10-
}
11-
126
fn ident<const W: usize, const H: usize>(v: [[u32; H]; W]) -> [[u32; H]; W] {
137
unsafe {
148
std::mem::transmute(v)
159
}
1610
}
1711

18-
fn flatten<const W: usize, const H: usize>(v: [[u32; H]; W]) -> [u32; W * H] {
19-
unsafe {
20-
std::mem::transmute(v)
21-
}
22-
}
23-
24-
fn coagulate<const W: usize, const H: usize>(v: [u32; H*W]) -> [[u32; W];H] {
25-
unsafe {
26-
std::mem::transmute(v)
27-
}
28-
}
29-
30-
fn flatten_3d<const W: usize, const H: usize, const D: usize>(
31-
v: [[[u32; D]; H]; W]
32-
) -> [u32; D * W * H] {
33-
unsafe {
34-
std::mem::transmute(v)
35-
}
36-
}
37-
38-
fn flatten_somewhat<const W: usize, const H: usize, const D: usize>(
39-
v: [[[u32; D]; H]; W]
40-
) -> [[u32; D * W]; H] {
41-
unsafe {
42-
std::mem::transmute(v)
43-
}
44-
}
45-
46-
fn known_size<const L: usize>(v: [u16; L]) -> [u8; L * 2] {
47-
unsafe {
48-
std::mem::transmute(v)
49-
}
50-
}
51-
52-
fn condense_bytes<const L: usize>(v: [u8; L * 2]) -> [u16; L] {
53-
unsafe {
54-
std::mem::transmute(v)
55-
}
56-
}
57-
58-
fn singleton_each<const L: usize>(v: [u8; L]) -> [[u8;1]; L] {
59-
unsafe {
60-
std::mem::transmute(v)
61-
}
62-
}
63-
64-
fn transpose_with_const<const W: usize, const H: usize>(
65-
v: [[u32; 2 * H]; W + W]
66-
) -> [[u32; W + W]; 2 * H] {
67-
unsafe {
68-
std::mem::transmute(v)
69-
}
70-
}
71-
7212
fn main() {
73-
let _ = transpose([[0; 8]; 16]);
74-
let _ = transpose_with_const::<8,4>([[0; 8]; 16]);
7513
let _ = ident([[0; 8]; 16]);
76-
let _ = flatten([[0; 13]; 5]);
77-
let _: [[_; 5]; 13] = coagulate([0; 65]);
78-
let _ = flatten_3d([[[0; 3]; 13]; 5]);
79-
let _ = flatten_somewhat([[[0; 3]; 13]; 5]);
80-
let _ = known_size([16; 13]);
81-
let _: [u16; 5] = condense_bytes([16u8; 10]);
82-
let _ = singleton_each([16; 10]);
8314
}

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