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rustc_target: TyAndLayout::field should never error.

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This commit is contained in:
Eduard-Mihai Burtescu
2021-08-25 18:05:10 +03:00
parent 87d1fb747f
commit 8e6d126b7d
10 changed files with 77 additions and 77 deletions
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101
compiler/rustc_middle/src/ty/layout.rs
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@@ -1788,22 +1788,18 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
let field_info: Vec<_> = flds
.iter()
.enumerate()
.map(|(i, &name)| match layout.field(self, i) {
Err(err) => {
bug!("no layout found for field {}: `{:?}`", name, err);
.map(|(i, &name)| {
let field_layout = layout.field(self, i);
let offset = layout.fields.offset(i);
let field_end = offset + field_layout.size;
if min_size < field_end {
min_size = field_end;
}
Ok(field_layout) => {
let offset = layout.fields.offset(i);
let field_end = offset + field_layout.size;
if min_size < field_end {
min_size = field_end;
}
FieldInfo {
name: name.to_string(),
offset: offset.bytes(),
size: field_layout.size.bytes(),
align: field_layout.align.abi.bytes(),
}
FieldInfo {
name: name.to_string(),
offset: offset.bytes(),
size: field_layout.size.bytes(),
align: field_layout.align.abi.bytes(),
}
})
.collect();
@@ -2146,30 +2142,24 @@ where
TyAndLayout { ty: this.ty, layout }
}
fn ty_and_layout_field(this: TyAndLayout<'tcx>, cx: &C, i: usize) -> C::TyAndLayout {
enum TyMaybeWithLayout<'tcx, C: LayoutOf<'tcx>> {
Ty(C::Ty),
TyAndLayout(C::TyAndLayout),
fn ty_and_layout_field(this: TyAndLayout<'tcx>, cx: &C, i: usize) -> TyAndLayout<'tcx> {
enum TyMaybeWithLayout<'tcx> {
Ty(Ty<'tcx>),
TyAndLayout(TyAndLayout<'tcx>),
}
fn ty_and_layout_kind<
C: LayoutOf<'tcx, Ty = Ty<'tcx>> + HasTyCtxt<'tcx> + HasParamEnv<'tcx>,
>(
fn field_ty_or_layout(
this: TyAndLayout<'tcx>,
cx: &C,
cx: &(impl HasTyCtxt<'tcx> + HasParamEnv<'tcx>),
i: usize,
ty: C::Ty,
) -> TyMaybeWithLayout<'tcx, C> {
) -> TyMaybeWithLayout<'tcx> {
let tcx = cx.tcx();
let tag_layout = |tag: &Scalar| -> C::TyAndLayout {
let tag_layout = |tag: &Scalar| -> TyAndLayout<'tcx> {
let layout = Layout::scalar(cx, tag.clone());
MaybeResult::from(Ok(TyAndLayout {
layout: tcx.intern_layout(layout),
ty: tag.value.to_ty(tcx),
}))
TyAndLayout { layout: tcx.intern_layout(layout), ty: tag.value.to_ty(tcx) }
};
match *ty.kind() {
match *this.ty.kind() {
ty::Bool
| ty::Char
| ty::Int(_)
@@ -2180,7 +2170,7 @@ where
| ty::FnDef(..)
| ty::GeneratorWitness(..)
| ty::Foreign(..)
| ty::Dynamic(..) => bug!("TyAndLayout::field_type({:?}): not applicable", this),
| ty::Dynamic(..) => bug!("TyAndLayout::field({:?}): not applicable", this),
// Potentially-fat pointers.
ty::Ref(_, pointee, _) | ty::RawPtr(ty::TypeAndMut { ty: pointee, .. }) => {
@@ -2192,17 +2182,19 @@ where
// as the `Abi` or `FieldsShape` is checked by users.
if i == 0 {
let nil = tcx.mk_unit();
let ptr_ty = if ty.is_unsafe_ptr() {
let unit_ptr_ty = if this.ty.is_unsafe_ptr() {
tcx.mk_mut_ptr(nil)
} else {
tcx.mk_mut_ref(tcx.lifetimes.re_static, nil)
};
return TyMaybeWithLayout::TyAndLayout(MaybeResult::from(
cx.layout_of(ptr_ty).to_result().map(|mut ptr_layout| {
ptr_layout.ty = ty;
ptr_layout
}),
));
// NOTE(eddyb) using an empty `ParamEnv`, and `unwrap`-ing
// the `Result` should always work because the type is
// always either `*mut ()` or `&'static mut ()`.
return TyMaybeWithLayout::TyAndLayout(TyAndLayout {
ty: this.ty,
..tcx.layout_of(ty::ParamEnv::reveal_all().and(unit_ptr_ty)).unwrap()
});
}
match tcx.struct_tail_erasing_lifetimes(pointee, cx.param_env()).kind() {
@@ -2226,7 +2218,7 @@ where
])
*/
}
_ => bug!("TyAndLayout::field_type({:?}): not applicable", this),
_ => bug!("TyAndLayout::field({:?}): not applicable", this),
}
}
@@ -2235,9 +2227,11 @@ where
ty::Str => TyMaybeWithLayout::Ty(tcx.types.u8),
// Tuples, generators and closures.
ty::Closure(_, ref substs) => {
ty_and_layout_kind(this, cx, i, substs.as_closure().tupled_upvars_ty())
}
ty::Closure(_, ref substs) => field_ty_or_layout(
TyAndLayout { ty: substs.as_closure().tupled_upvars_ty(), ..this },
cx,
i,
),
ty::Generator(def_id, ref substs, _) => match this.variants {
Variants::Single { index } => TyMaybeWithLayout::Ty(
@@ -2280,14 +2274,25 @@ where
| ty::Opaque(..)
| ty::Param(_)
| ty::Infer(_)
| ty::Error(_) => bug!("TyAndLayout::field_type: unexpected type `{}`", this.ty),
| ty::Error(_) => bug!("TyAndLayout::field: unexpected type `{}`", this.ty),
}
}
cx.layout_of(match ty_and_layout_kind(this, cx, i, this.ty) {
TyMaybeWithLayout::Ty(result) => result,
TyMaybeWithLayout::TyAndLayout(result) => return result,
})
match field_ty_or_layout(this, cx, i) {
TyMaybeWithLayout::Ty(field_ty) => {
cx.tcx().layout_of(cx.param_env().and(field_ty)).unwrap_or_else(|e| {
bug!(
"failed to get layout for `{}`: {},\n\
despite it being a field (#{}) of an existing layout: {:#?}",
field_ty,
e,
i,
this
)
})
}
TyMaybeWithLayout::TyAndLayout(field_layout) => field_layout,
}
}
fn ty_and_layout_pointee_info_at(