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layout computation: eagerly error for unexpected unsized fields

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This commit is contained in:
Lukas Markeffsky
2024-09-15 22:16:21 +02:00
parent 16be6666d4
commit 697450151c
25 changed files with 1246 additions and 1115 deletions
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98
compiler/rustc_ty_utils/src/layout.rs
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@@ -9,7 +9,7 @@ use rustc_middle::bug;
use rustc_middle::mir::{CoroutineLayout, CoroutineSavedLocal};
use rustc_middle::query::Providers;
use rustc_middle::ty::layout::{
FloatExt, IntegerExt, LayoutCx, LayoutError, LayoutOf, TyAndLayout, MAX_SIMD_LANES,
FloatExt, HasTyCtxt, IntegerExt, LayoutCx, LayoutError, LayoutOf, TyAndLayout, MAX_SIMD_LANES,
};
use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_middle::ty::{
@@ -63,14 +63,14 @@ fn layout_of<'tcx>(
return tcx.layout_of(param_env.and(ty));
}
let cx = LayoutCx { tcx, param_env };
let cx = LayoutCx::new(tcx, param_env);
let layout = layout_of_uncached(&cx, ty)?;
let layout = TyAndLayout { ty, layout };
// If we are running with `-Zprint-type-sizes`, maybe record layouts
// for dumping later.
if cx.tcx.sess.opts.unstable_opts.print_type_sizes {
if cx.tcx().sess.opts.unstable_opts.print_type_sizes {
record_layout_for_printing(&cx, layout);
}
@@ -80,7 +80,36 @@ fn layout_of<'tcx>(
}
fn error<'tcx>(cx: &LayoutCx<'tcx>, err: LayoutError<'tcx>) -> &'tcx LayoutError<'tcx> {
cx.tcx.arena.alloc(err)
cx.tcx().arena.alloc(err)
}
fn map_error<'tcx>(
cx: &LayoutCx<'tcx>,
ty: Ty<'tcx>,
err: LayoutCalculatorError,
) -> &'tcx LayoutError<'tcx> {
let err = match err {
LayoutCalculatorError::SizeOverflow => {
// This is sometimes not a compile error in `check` builds.
LayoutError::SizeOverflow(ty)
}
LayoutCalculatorError::UnexpectedUnsized => {
// This is sometimes not a compile error if there are trivially false where
// clauses, but it is always a compiler error in the empty environment.
if cx.param_env.caller_bounds().is_empty() {
cx.tcx().dcx().delayed_bug(format!(
"encountered unexpected unsized field in layout of {ty:?}"
));
}
LayoutError::Unknown(ty)
}
LayoutCalculatorError::EmptyUnion => {
// This is always a compile error.
cx.tcx().dcx().delayed_bug(format!("computed layout of empty union: {ty:?}"));
LayoutError::Unknown(ty)
}
};
error(cx, err)
}
fn univariant_uninterned<'tcx>(
@@ -90,13 +119,12 @@ fn univariant_uninterned<'tcx>(
repr: &ReprOptions,
kind: StructKind,
) -> Result<LayoutS<FieldIdx, VariantIdx>, &'tcx LayoutError<'tcx>> {
let dl = cx.data_layout();
let pack = repr.pack;
if pack.is_some() && repr.align.is_some() {
cx.tcx.dcx().bug("struct cannot be packed and aligned");
cx.tcx().dcx().bug("struct cannot be packed and aligned");
}
cx.univariant(dl, fields, repr, kind).ok_or_else(|| error(cx, LayoutError::SizeOverflow(ty)))
cx.calc.univariant(fields, repr, kind).map_err(|err| map_error(cx, ty, err))
}
fn layout_of_uncached<'tcx>(
@@ -110,7 +138,7 @@ fn layout_of_uncached<'tcx>(
return Err(error(cx, LayoutError::ReferencesError(guar)));
}
let tcx = cx.tcx;
let tcx = cx.tcx();
let param_env = cx.param_env;
let dl = cx.data_layout();
let scalar_unit = |value: Primitive| {
@@ -188,7 +216,7 @@ fn layout_of_uncached<'tcx>(
}
// The never type.
ty::Never => tcx.mk_layout(cx.layout_of_never_type()),
ty::Never => tcx.mk_layout(cx.calc.layout_of_never_type()),
// Potentially-wide pointers.
ty::Ref(_, pointee, _) | ty::RawPtr(pointee, _) => {
@@ -264,7 +292,7 @@ fn layout_of_uncached<'tcx>(
};
// Effectively a (ptr, meta) tuple.
tcx.mk_layout(cx.scalar_pair(data_ptr, metadata))
tcx.mk_layout(cx.calc.scalar_pair(data_ptr, metadata))
}
ty::Dynamic(_, _, ty::DynStar) => {
@@ -272,7 +300,7 @@ fn layout_of_uncached<'tcx>(
data.valid_range_mut().start = 0;
let mut vtable = scalar_unit(Pointer(AddressSpace::DATA));
vtable.valid_range_mut().start = 1;
tcx.mk_layout(cx.scalar_pair(data, vtable))
tcx.mk_layout(cx.calc.scalar_pair(data, vtable))
}
// Arrays and slices.
@@ -531,7 +559,7 @@ fn layout_of_uncached<'tcx>(
if def.is_union() {
if def.repr().pack.is_some() && def.repr().align.is_some() {
cx.tcx.dcx().span_delayed_bug(
tcx.dcx().span_delayed_bug(
tcx.def_span(def.did()),
"union cannot be packed and aligned",
);
@@ -539,8 +567,9 @@ fn layout_of_uncached<'tcx>(
}
return Ok(tcx.mk_layout(
cx.layout_of_union(&def.repr(), &variants)
.ok_or_else(|| error(cx, LayoutError::Unknown(ty)))?,
cx.calc
.layout_of_union(&def.repr(), &variants)
.map_err(|err| map_error(cx, ty, err))?,
));
}
@@ -557,7 +586,7 @@ fn layout_of_uncached<'tcx>(
})?;
if is_unsized {
cx.tcx.dcx().span_delayed_bug(tcx.def_span(def.did()), err_msg.to_owned());
tcx.dcx().span_delayed_bug(tcx.def_span(def.did()), err_msg.to_owned());
Err(error(cx, LayoutError::Unknown(ty)))
} else {
Ok(())
@@ -600,19 +629,20 @@ fn layout_of_uncached<'tcx>(
!tcx.type_of(last_field.did).instantiate_identity().is_sized(tcx, param_env)
});
let Some(layout) = cx.layout_of_struct_or_enum(
&def.repr(),
&variants,
def.is_enum(),
def.is_unsafe_cell(),
tcx.layout_scalar_valid_range(def.did()),
get_discriminant_type,
discriminants_iter(),
dont_niche_optimize_enum,
!maybe_unsized,
) else {
return Err(error(cx, LayoutError::SizeOverflow(ty)));
};
let layout = cx
.calc
.layout_of_struct_or_enum(
&def.repr(),
&variants,
def.is_enum(),
def.is_unsafe_cell(),
tcx.layout_scalar_valid_range(def.did()),
get_discriminant_type,
discriminants_iter(),
dont_niche_optimize_enum,
!maybe_unsized,
)
.map_err(|err| map_error(cx, ty, err))?;
// If the struct tail is sized and can be unsized, check that unsizing doesn't move the fields around.
if cfg!(debug_assertions)
@@ -623,7 +653,7 @@ fn layout_of_uncached<'tcx>(
let tail_replacement = cx.layout_of(Ty::new_slice(tcx, tcx.types.u8)).unwrap();
*variants[FIRST_VARIANT].raw.last_mut().unwrap() = tail_replacement.layout;
let Some(unsized_layout) = cx.layout_of_struct_or_enum(
let Ok(unsized_layout) = cx.calc.layout_of_struct_or_enum(
&def.repr(),
&variants,
def.is_enum(),
@@ -812,7 +842,7 @@ fn coroutine_layout<'tcx>(
args: GenericArgsRef<'tcx>,
) -> Result<Layout<'tcx>, &'tcx LayoutError<'tcx>> {
use SavedLocalEligibility::*;
let tcx = cx.tcx;
let tcx = cx.tcx();
let instantiate_field = |ty: Ty<'tcx>| EarlyBinder::bind(ty).instantiate(tcx, args);
let Some(info) = tcx.coroutine_layout(def_id, args.as_coroutine().kind_ty()) else {
@@ -832,7 +862,7 @@ fn coroutine_layout<'tcx>(
value: Primitive::Int(discr_int, false),
valid_range: WrappingRange { start: 0, end: max_discr },
};
let tag_layout = cx.tcx.mk_layout(LayoutS::scalar(cx, tag));
let tag_layout = tcx.mk_layout(LayoutS::scalar(cx, tag));
let promoted_layouts = ineligible_locals.iter().map(|local| {
let field_ty = instantiate_field(info.field_tys[local].ty);
@@ -1025,7 +1055,7 @@ fn record_layout_for_printing<'tcx>(cx: &LayoutCx<'tcx>, layout: TyAndLayout<'tc
// (delay format until we actually need it)
let record = |kind, packed, opt_discr_size, variants| {
let type_desc = with_no_trimmed_paths!(format!("{}", layout.ty));
cx.tcx.sess.code_stats.record_type_size(
cx.tcx().sess.code_stats.record_type_size(
kind,
type_desc,
layout.align.abi,
@@ -1148,8 +1178,8 @@ fn variant_info_for_coroutine<'tcx>(
return (vec![], None);
};
let coroutine = cx.tcx.coroutine_layout(def_id, args.as_coroutine().kind_ty()).unwrap();
let upvar_names = cx.tcx.closure_saved_names_of_captured_variables(def_id);
let coroutine = cx.tcx().coroutine_layout(def_id, args.as_coroutine().kind_ty()).unwrap();
let upvar_names = cx.tcx().closure_saved_names_of_captured_variables(def_id);
let mut upvars_size = Size::ZERO;
let upvar_fields: Vec<_> = args