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fix homogeneous_aggregate not ignoring some 1-ZST

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This commit is contained in:
Ralf Jung 2023-09-10 07:38:03 +02:00
parent 38bbc2ce03
commit 254e13d9f9
4 changed files with 88 additions and 13 deletions
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15
compiler/rustc_target/src/abi/call/mod.rs
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@ -382,8 +382,7 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
/// only a single type (e.g., `(u32, u32)`). Such aggregates are often
/// special-cased in ABIs.
///
/// Note: We generally ignore fields of zero-sized type when computing
/// this value (see #56877).
/// Note: We generally ignore 1-ZST fields when computing this value (see #56877).
///
/// This is public so that it can be used in unit tests, but
/// should generally only be relevant to the ABI details of
@ -441,11 +440,17 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
let mut total = start;
for i in 0..layout.fields.count() {
if !is_union && total != layout.fields.offset(i) {
return Err(Heterogeneous);
let field = layout.field(cx, i);
if field.is_1zst() {
// No data here and no impact on layout, can be ignored.
// (We might be able to also ignore all aligned ZST but that's less clear.)
continue;
}
let field = layout.field(cx, i);
if !is_union && total != layout.fields.offset(i) {
// This field isn't just after the previous one we considered, abort.
return Err(Heterogeneous);
}
result = result.merge(field.homogeneous_aggregate(cx)?)?;