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Rollup merge of #125672 - Lokathor:update-miri-result-ffi, r=RalfJung

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Add more ABI test cases to miri (RFC 3391)

Part of https://github.com/rust-lang/rust/issues/110503

cc `@RalfJung`
This commit is contained in:
Matthias Krüger 2024-06-05 18:21:12 +02:00 committed by GitHub
commit 36cab1260d
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2 changed files with 37 additions and 12 deletions
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33
compiler/rustc_const_eval/src/interpret/terminator.rs
View File

@ -294,17 +294,30 @@ fn unfold_transparent(
/// Unwrap types that are guaranteed a null-pointer-optimization
fn unfold_npo(&self, layout: TyAndLayout<'tcx>) -> InterpResult<'tcx, TyAndLayout<'tcx>> {
// Check if this is `Option` wrapping some type.
let inner = match layout.ty.kind() {
ty::Adt(def, args) if self.tcx.is_diagnostic_item(sym::Option, def.did()) => {
args[0].as_type().unwrap()
}
_ => {
// Not an `Option`.
return Ok(layout);
}
// Check if this is `Option` wrapping some type or if this is `Result` wrapping a 1-ZST and
// another type.
let ty::Adt(def, args) = layout.ty.kind() else {
// Not an ADT, so definitely no NPO.
return Ok(layout);
};
let inner = self.layout_of(inner)?;
let inner = if self.tcx.is_diagnostic_item(sym::Option, def.did()) {
// The wrapped type is the only arg.
self.layout_of(args[0].as_type().unwrap())?
} else if self.tcx.is_diagnostic_item(sym::Result, def.did()) {
// We want to extract which (if any) of the args is not a 1-ZST.
let lhs = self.layout_of(args[0].as_type().unwrap())?;
let rhs = self.layout_of(args[1].as_type().unwrap())?;
if lhs.is_1zst() {
rhs
} else if rhs.is_1zst() {
lhs
} else {
return Ok(layout); // no NPO
}
} else {
return Ok(layout); // no NPO
};
// Check if the inner type is one of the NPO-guaranteed ones.
// For that we first unpeel transparent *structs* (but not unions).
let is_npo = |def: AdtDef<'tcx>| {

16
src/tools/miri/tests/pass/function_calls/abi_compat.rs
View File

@ -83,12 +83,24 @@ fn main() {
test_abi_compat(main as fn(), id::<i32> as fn(i32) -> i32);
// - 1-ZST
test_abi_compat((), [0u8; 0]);
// - Guaranteed null-pointer-optimizations (RFC 3391).
// - Guaranteed Option<X> null-pointer-optimizations (RFC 3391).
test_abi_compat(&0u32 as *const u32, Some(&0u32));
test_abi_compat(main as fn(), Some(main as fn()));
test_abi_compat(0u32, Some(num::NonZero::new(1u32).unwrap()));
test_abi_compat(&0u32 as *const u32, Some(Wrapper(&0u32)));
test_abi_compat(0u32, Some(Wrapper(num::NonZero::new(1u32).unwrap())));
test_abi_compat(0u32, Some(Wrapper(num::NonZeroU32::new(1u32).unwrap())));
// - Guaranteed Result<X, ZST1> does the same as Option<X> (RFC 3391)
test_abi_compat(&0u32 as *const u32, Result::<_, ()>::Ok(&0u32));
test_abi_compat(main as fn(), Result::<_, ()>::Ok(main as fn()));
test_abi_compat(0u32, Result::<_, ()>::Ok(num::NonZeroU32::new(1).unwrap()));
test_abi_compat(&0u32 as *const u32, Result::<_, ()>::Ok(Wrapper(&0u32)));
test_abi_compat(0u32, Result::<_, ()>::Ok(Wrapper(num::NonZeroU32::new(1).unwrap())));
// - Guaranteed Result<ZST1, X> also does the same as Option<X> (RFC 3391)
test_abi_compat(&0u32 as *const u32, Result::<(), _>::Err(&0u32));
test_abi_compat(main as fn(), Result::<(), _>::Err(main as fn()));
test_abi_compat(0u32, Result::<(), _>::Err(num::NonZeroU32::new(1).unwrap()));
test_abi_compat(&0u32 as *const u32, Result::<(), _>::Err(Wrapper(&0u32)));
test_abi_compat(0u32, Result::<(), _>::Err(Wrapper(num::NonZeroU32::new(1).unwrap())));
// These must work for *any* type, since we guarantee that `repr(transparent)` is ABI-compatible
// with the wrapped field.