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Enums in offset_of: update based on est31, scottmcm & llogiq review

This commit is contained in:
George Bateman 2023-08-15 22:32:55 +01:00
parent e936416a8d
commit d995bd61e7
No known key found for this signature in database
GPG Key ID: C417AA9C4039EFCF
15 changed files with 150 additions and 140 deletions
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7
compiler/rustc_abi/src/lib.rs
View File

@ -1133,13 +1133,6 @@ rustc_index::newtype_index! {
pub struct FieldIdx {}
}
/// `offset_of` can traverse fields and enum variants and should keep track of which is which.
#[derive(Copy, Clone, Debug, Eq, Hash, HashStable_Generic, PartialEq, Encodable, Decodable)]
pub enum OffsetOfIdx {
Field(FieldIdx),
Variant(VariantIdx),
}
/// Describes how the fields of a type are located in memory.
#[derive(PartialEq, Eq, Hash, Clone, Debug)]
#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]

36
compiler/rustc_const_eval/src/transform/validate.rs
View File

@ -1062,13 +1062,17 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
};
let mut current_ty = *container;
let mut indices = indices.into_iter();
use rustc_target::abi::OffsetOfIdx::*;
while let Some(index) = indices.next() {
match (current_ty.kind(), index) {
(ty::Tuple(fields), Field(field)) => {
for (variant, field) in indices.iter() {
match current_ty.kind() {
ty::Tuple(fields) => {
if variant != FIRST_VARIANT {
self.fail(
location,
format!("tried to get variant {variant:?} of tuple"),
);
return;
}
let Some(&f_ty) = fields.get(field.as_usize()) else {
fail_out_of_bounds(self, location, field, current_ty);
return;
@ -1076,23 +1080,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
current_ty = self.tcx.normalize_erasing_regions(self.param_env, f_ty);
}
(ty::Adt(adt_def, args), Field(field)) if !adt_def.is_enum() => {
let Some(field) = adt_def.non_enum_variant().fields.get(field) else {
fail_out_of_bounds(self, location, field, current_ty);
return;
};
let f_ty = field.ty(self.tcx, args);
current_ty = self.tcx.normalize_erasing_regions(self.param_env, f_ty);
}
(ty::Adt(adt_def, args), Variant(variant)) if adt_def.is_enum() => {
let Some(Field(field)) = indices.next() else {
self.fail(
location,
format!("enum variant must be followed by field index in offset_of; in {current_ty:?}"),
);
return;
};
ty::Adt(adt_def, args) => {
let Some(field) = adt_def.variant(variant).fields.get(field) else {
fail_out_of_bounds(self, location, field, current_ty);
return;
@ -1104,7 +1092,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
_ => {
self.fail(
location,
format!("Cannot get offset {index:?} from type {current_ty:?}"),
format!("Cannot get offset ({variant:?}, {field:?}) from type {current_ty:?}"),
);
return;
}

101
compiler/rustc_hir_typeck/src/expr.rs
View File

@ -54,7 +54,7 @@ use rustc_span::edit_distance::find_best_match_for_name;
use rustc_span::hygiene::DesugaringKind;
use rustc_span::source_map::{Span, Spanned};
use rustc_span::symbol::{kw, sym, Ident, Symbol};
use rustc_target::abi::FieldIdx;
use rustc_target::abi::{FieldIdx, FIRST_VARIANT};
use rustc_target::spec::abi::Abi::RustIntrinsic;
use rustc_trait_selection::infer::InferCtxtExt;
use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt;
@ -3103,8 +3103,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
fields: &[Ident],
expr: &'tcx hir::Expr<'tcx>,
) -> Ty<'tcx> {
use rustc_target::abi::OffsetOfIdx::*;
let container = self.to_ty(container).normalized;
let mut field_indices = Vec::with_capacity(fields.len());
@ -3120,49 +3118,68 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let (ident, _def_scope) =
self.tcx.adjust_ident_and_get_scope(field, container_def.did(), block);
if let Some((index, variant)) = container_def.variants()
let Some((index, variant)) = container_def.variants()
.iter_enumerated()
.find(|(_, v)| v.ident(self.tcx).normalize_to_macros_2_0() == ident)
{
let Some(&subfield) = fields.next() else {
let mut err = type_error_struct!(
self.tcx().sess,
ident.span,
container,
E0795,
"`{ident}` is an enum variant; expected field at end of `offset_of`",
);
err.span_label(field.span, "enum variant");
err.emit();
break;
};
let (subident, sub_def_scope) =
self.tcx.adjust_ident_and_get_scope(subfield, variant.def_id, block);
.find(|(_, v)| v.ident(self.tcx).normalize_to_macros_2_0() == ident) else {
let mut err = type_error_struct!(
self.tcx().sess,
ident.span,
container,
E0599,
"no variant named `{ident}` found for enum `{container}`",
);
err.span_label(field.span, "variant not found");
err.emit();
break;
};
let Some(&subfield) = fields.next() else {
let mut err = type_error_struct!(
self.tcx().sess,
ident.span,
container,
E0795,
"`{ident}` is an enum variant; expected field at end of `offset_of`",
);
err.span_label(field.span, "enum variant");
err.emit();
break;
};
let (subident, sub_def_scope) =
self.tcx.adjust_ident_and_get_scope(subfield, variant.def_id, block);
if let Some((subindex, field)) = variant.fields
.iter_enumerated()
.find(|(_, f)| f.ident(self.tcx).normalize_to_macros_2_0() == subident)
{
let field_ty = self.field_ty(expr.span, field, args);
let Some((subindex, field)) = variant.fields
.iter_enumerated()
.find(|(_, f)| f.ident(self.tcx).normalize_to_macros_2_0() == subident) else {
let mut err = type_error_struct!(
self.tcx().sess,
ident.span,
container,
E0609,
"no field named `{subfield}` on enum variant `{container}::{ident}`",
);
err.span_label(field.span, "this enum variant...");
err.span_label(subident.span, "...does not have this field");
err.emit();
break;
};
// FIXME: DSTs with static alignment should be allowed
self.require_type_is_sized(field_ty, expr.span, traits::MiscObligation);
let field_ty = self.field_ty(expr.span, field, args);
if field.vis.is_accessible_from(sub_def_scope, self.tcx) {
self.tcx.check_stability(field.did, Some(expr.hir_id), expr.span, None);
} else {
self.private_field_err(ident, container_def.did()).emit();
}
// FIXME: DSTs with static alignment should be allowed
self.require_type_is_sized(field_ty, expr.span, traits::MiscObligation);
// Save the index of all fields regardless of their visibility in case
// of error recovery.
field_indices.push(Variant(index));
field_indices.push(Field(subindex));
current_container = field_ty;
continue;
}
if field.vis.is_accessible_from(sub_def_scope, self.tcx) {
self.tcx.check_stability(field.did, Some(expr.hir_id), expr.span, None);
} else {
self.private_field_err(ident, container_def.did()).emit();
}
// Save the index of all fields regardless of their visibility in case
// of error recovery.
field_indices.push((index, subindex));
current_container = field_ty;
continue;
}
ty::Adt(container_def, args) => {
let block = self.tcx.hir().local_def_id_to_hir_id(self.body_id);
@ -3187,7 +3204,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
// Save the index of all fields regardless of their visibility in case
// of error recovery.
field_indices.push(Field(index));
field_indices.push((FIRST_VARIANT, index));
current_container = field_ty;
continue;
@ -3201,7 +3218,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
self.require_type_is_sized(ty, expr.span, traits::MiscObligation);
}
if let Some(&field_ty) = tys.get(index) {
field_indices.push(Field(index.into()));
field_indices.push((FIRST_VARIANT, index.into()));
current_container = field_ty;
continue;

4
compiler/rustc_middle/src/mir/syntax.rs
View File

@ -17,7 +17,7 @@ use rustc_hir::def_id::DefId;
use rustc_hir::{self as hir};
use rustc_hir::{self, CoroutineKind};
use rustc_index::IndexVec;
use rustc_target::abi::{FieldIdx, OffsetOfIdx, VariantIdx};
use rustc_target::abi::{FieldIdx, VariantIdx};
use rustc_ast::Mutability;
use rustc_span::def_id::LocalDefId;
@ -1354,7 +1354,7 @@ pub enum NullOp<'tcx> {
/// Returns the minimum alignment of a type
AlignOf,
/// Returns the offset of a field
OffsetOf(&'tcx List<OffsetOfIdx>),
OffsetOf(&'tcx List<(VariantIdx, FieldIdx)>),
}
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]

4
compiler/rustc_middle/src/thir.rs
View File

@ -26,7 +26,7 @@ use rustc_middle::ty::{
use rustc_span::def_id::LocalDefId;
use rustc_span::{sym, ErrorGuaranteed, Span, Symbol, DUMMY_SP};
use rustc_span::{sym, Span, Symbol, DUMMY_SP};
use rustc_target::abi::{FieldIdx, OffsetOfIdx, VariantIdx};
use rustc_target::abi::{FieldIdx, VariantIdx};
use rustc_target::asm::InlineAsmRegOrRegClass;
use std::fmt;
use std::ops::Index;
@ -491,7 +491,7 @@ pub enum ExprKind<'tcx> {
/// Field offset (`offset_of!`)
OffsetOf {
container: Ty<'tcx>,
fields: &'tcx List<OffsetOfIdx>,
fields: &'tcx List<(VariantIdx, FieldIdx)>,
},
/// An expression taking a reference to a thread local.
ThreadLocalRef(DefId),

14
compiler/rustc_middle/src/ty/codec.rs
View File

@ -19,7 +19,7 @@ use rustc_data_structures::fx::FxHashMap;
use rustc_middle::ty::TyCtxt;
use rustc_serialize::{Decodable, Encodable};
use rustc_span::Span;
use rustc_target::abi::{FieldIdx, OffsetOfIdx};
use rustc_target::abi::{FieldIdx, VariantIdx};
pub use rustc_type_ir::{TyDecoder, TyEncoder};
use std::hash::Hash;
use std::intrinsics;
@ -414,12 +414,14 @@ impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> RefDecodable<'tcx, D> for ty::List<Fi
}
}
impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> RefDecodable<'tcx, D> for ty::List<OffsetOfIdx> {
impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> RefDecodable<'tcx, D>
for ty::List<(VariantIdx, FieldIdx)>
{
fn decode(decoder: &mut D) -> &'tcx Self {
let len = decoder.read_usize();
decoder
.interner()
.mk_offset_of_from_iter((0..len).map::<OffsetOfIdx, _>(|_| Decodable::decode(decoder)))
decoder.interner().mk_offset_of_from_iter(
(0..len).map::<(VariantIdx, FieldIdx), _>(|_| Decodable::decode(decoder)),
)
}
}
@ -435,7 +437,7 @@ impl_decodable_via_ref! {
&'tcx ty::List<ty::BoundVariableKind>,
&'tcx ty::List<ty::Clause<'tcx>>,
&'tcx ty::List<FieldIdx>,
&'tcx ty::List<OffsetOfIdx>,
&'tcx ty::List<(VariantIdx, FieldIdx)>,
}
#[macro_export]

8
compiler/rustc_middle/src/ty/context.rs
View File

@ -63,7 +63,7 @@ use rustc_session::{Limit, MetadataKind, Session};
use rustc_span::def_id::{DefPathHash, StableCrateId};
use rustc_span::symbol::{kw, sym, Ident, Symbol};
use rustc_span::{Span, DUMMY_SP};
use rustc_target::abi::{FieldIdx, Layout, LayoutS, OffsetOfIdx, TargetDataLayout, VariantIdx};
use rustc_target::abi::{FieldIdx, Layout, LayoutS, TargetDataLayout, VariantIdx};
use rustc_target::spec::abi;
use rustc_type_ir::TyKind::*;
use rustc_type_ir::WithCachedTypeInfo;
@ -163,7 +163,7 @@ pub struct CtxtInterners<'tcx> {
predefined_opaques_in_body: InternedSet<'tcx, PredefinedOpaquesData<'tcx>>,
fields: InternedSet<'tcx, List<FieldIdx>>,
local_def_ids: InternedSet<'tcx, List<LocalDefId>>,
offset_of: InternedSet<'tcx, List<OffsetOfIdx>>,
offset_of: InternedSet<'tcx, List<(VariantIdx, FieldIdx)>>,
}
impl<'tcx> CtxtInterners<'tcx> {
@ -1589,7 +1589,7 @@ slice_interners!(
bound_variable_kinds: pub mk_bound_variable_kinds(ty::BoundVariableKind),
fields: pub mk_fields(FieldIdx),
local_def_ids: intern_local_def_ids(LocalDefId),
offset_of: pub mk_offset_of(OffsetOfIdx),
offset_of: pub mk_offset_of((VariantIdx, FieldIdx)),
);
impl<'tcx> TyCtxt<'tcx> {
@ -1920,7 +1920,7 @@ impl<'tcx> TyCtxt<'tcx> {
pub fn mk_offset_of_from_iter<I, T>(self, iter: I) -> T::Output
where
I: Iterator<Item = T>,
T: CollectAndApply<OffsetOfIdx, &'tcx List<OffsetOfIdx>>,
T: CollectAndApply<(VariantIdx, FieldIdx), &'tcx List<(VariantIdx, FieldIdx)>>,
{
T::collect_and_apply(iter, |xs| self.mk_offset_of(xs))
}

10
compiler/rustc_middle/src/ty/typeck_results.rs
View File

@ -24,7 +24,7 @@ use rustc_macros::HashStable;
use rustc_middle::mir::FakeReadCause;
use rustc_session::Session;
use rustc_span::Span;
use rustc_target::abi::{FieldIdx, OffsetOfIdx};
use rustc_target::abi::{FieldIdx, VariantIdx};
use std::{collections::hash_map::Entry, hash::Hash, iter};
use super::RvalueScopes;
@ -205,7 +205,7 @@ pub struct TypeckResults<'tcx> {
pub closure_size_eval: LocalDefIdMap<ClosureSizeProfileData<'tcx>>,
/// Container types and field indices of `offset_of!` expressions
offset_of_data: ItemLocalMap<(Ty<'tcx>, Vec<OffsetOfIdx>)>,
offset_of_data: ItemLocalMap<(Ty<'tcx>, Vec<(VariantIdx, FieldIdx)>)>,
}
impl<'tcx> TypeckResults<'tcx> {
@ -464,13 +464,15 @@ impl<'tcx> TypeckResults<'tcx> {
&self.coercion_casts
}
pub fn offset_of_data(&self) -> LocalTableInContext<'_, (Ty<'tcx>, Vec<OffsetOfIdx>)> {
pub fn offset_of_data(
&self,
) -> LocalTableInContext<'_, (Ty<'tcx>, Vec<(VariantIdx, FieldIdx)>)> {
LocalTableInContext { hir_owner: self.hir_owner, data: &self.offset_of_data }
}
pub fn offset_of_data_mut(
&mut self,
) -> LocalTableInContextMut<'_, (Ty<'tcx>, Vec<OffsetOfIdx>)> {
) -> LocalTableInContextMut<'_, (Ty<'tcx>, Vec<(VariantIdx, FieldIdx)>)> {
LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.offset_of_data }
}
}

25
compiler/rustc_passes/src/dead.rs
View File

@ -248,8 +248,6 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
}
fn handle_offset_of(&mut self, expr: &'tcx hir::Expr<'tcx>) {
use rustc_target::abi::OffsetOfIdx::*;
let data = self.typeck_results().offset_of_data();
let &(container, ref indices) =
data.get(expr.hir_id).expect("no offset_of_data for offset_of");
@ -258,22 +256,10 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
let param_env = self.tcx.param_env(body_did);
let mut current_ty = container;
let mut indices = indices.into_iter();
while let Some(&index) = indices.next() {
match (current_ty.kind(), index) {
(ty::Adt(def, subst), Field(field)) if !def.is_enum() => {
let field = &def.non_enum_variant().fields[field];
self.insert_def_id(field.did);
let field_ty = field.ty(self.tcx, subst);
current_ty = self.tcx.normalize_erasing_regions(param_env, field_ty);
}
(ty::Adt(def, subst), Variant(variant)) if def.is_enum() => {
let Some(&Field(field)) = indices.next() else {
span_bug!(expr.span, "variant must be followed by field in offset_of")
};
for &(variant, field) in indices {
match current_ty.kind() {
ty::Adt(def, subst) => {
let field = &def.variant(variant).fields[field];
self.insert_def_id(field.did);
@ -283,12 +269,11 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
}
// we don't need to mark tuple fields as live,
// but we may need to mark subfields
(ty::Tuple(tys), Field(field)) => {
ty::Tuple(tys) => {
current_ty =
self.tcx.normalize_erasing_regions(param_env, tys[field.as_usize()]);
}
(_, Field(_)) => span_bug!(expr.span, "named field access on non-ADT"),
(_, Variant(_)) => span_bug!(expr.span, "enum variant access on non-enum"),
_ => span_bug!(expr.span, "named field access on non-ADT"),
}
}
}

11
compiler/rustc_smir/src/rustc_smir/mod.rs
View File

@ -16,7 +16,7 @@ use rustc_middle::mir::interpret::{alloc_range, AllocId};
use rustc_middle::mir::mono::MonoItem;
use rustc_middle::ty::{self, Instance, ParamEnv, Ty, TyCtxt, Variance};
use rustc_span::def_id::{CrateNum, DefId, LOCAL_CRATE};
use rustc_target::abi::{FieldIdx, OffsetOfIdx};
use rustc_target::abi::FieldIdx;
use stable_mir::mir::mono::InstanceDef;
use stable_mir::mir::{Body, CopyNonOverlapping, Statement, UserTypeProjection, VariantIdx};
use stable_mir::ty::{
@ -643,13 +643,10 @@ impl<'tcx> Stable<'tcx> for FieldIdx {
}
}
impl<'tcx> Stable<'tcx> for OffsetOfIdx {
type T = usize;
impl<'tcx> Stable<'tcx> for (rustc_target::abi::VariantIdx, FieldIdx) {
type T = (usize, usize);
fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
match self {
OffsetOfIdx::Field(f) => f.as_usize(),
OffsetOfIdx::Variant(v) => v.as_usize(),
}
(self.0.as_usize(), self.1.as_usize())
}
}

29
compiler/rustc_target/src/abi/mod.rs
View File

@ -250,29 +250,24 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
Ty::is_transparent(self)
}
pub fn offset_of_subfield<C>(self, cx: &C, indices: impl Iterator<Item = OffsetOfIdx>) -> Size
pub fn offset_of_subfield<C, I>(self, cx: &C, indices: I) -> Size
where
Ty: TyAbiInterface<'a, C>,
I: Iterator<Item = (VariantIdx, FieldIdx)>,
{
let mut layout = self;
let mut offset = Size::ZERO;
for index in indices {
match index {
OffsetOfIdx::Field(field) => {
let index = field.index();
offset += layout.fields.offset(index);
layout = layout.field(cx, index);
assert!(
layout.is_sized(),
"offset of unsized field (type {:?}) cannot be computed statically",
layout.ty
);
}
OffsetOfIdx::Variant(variant) => {
layout = layout.for_variant(cx, variant);
}
}
for (variant, field) in indices {
layout = layout.for_variant(cx, variant);
let index = field.index();
offset += layout.fields.offset(index);
layout = layout.field(cx, index);
assert!(
layout.is_sized(),
"offset of unsized field (type {:?}) cannot be computed statically",
layout.ty
);
}
offset

2
compiler/stable_mir/src/mir/body.rs
View File

@ -514,7 +514,7 @@ pub enum NullOp {
/// Returns the minimum alignment of a type.
AlignOf,
/// Returns the offset of a field.
OffsetOf(Vec<FieldIdx>),
OffsetOf(Vec<(VariantIdx, FieldIdx)>),
}
impl Operand {

10
library/core/src/mem/mod.rs
View File

@ -1292,11 +1292,15 @@ impl<T> SizedTypeProperties for T {}
/// Expands to the offset in bytes of a field from the beginning of the given type.
///
/// Only structs, unions and tuples are supported.
/// Structs, enums, unions and tuples are supported.
///
/// Nested field accesses may be used, but not array indexes like in `C`'s `offsetof`.
///
/// Note that the output of this macro is not stable, except for `#[repr(C)]` types.
/// Enum variants may be traversed as if they were fields. Variants themselves do
/// not have an offset.
///
/// Note that type layout is, in general, [platform-specific, and subject to
/// change](https://doc.rust-lang.org/reference/type-layout.html).
///
/// # Examples
///
@ -1324,6 +1328,8 @@ impl<T> SizedTypeProperties for T {}
/// struct NestedB(u8);
///
/// assert_eq!(mem::offset_of!(NestedA, b.0), 0);
///
/// assert_eq!(mem::offset_of!(Option<&u8>, Some.0), 0);
/// ```
#[unstable(feature = "offset_of", issue = "106655")]
#[allow_internal_unstable(builtin_syntax, hint_must_use)]

3
tests/ui/offset-of/offset-of-enum.rs
View File

@ -11,4 +11,7 @@ fn main() {
offset_of!(Alpha::One, 0); //~ ERROR expected type, found variant `Alpha::One`
offset_of!(Alpha, One); //~ ERROR `One` is an enum variant; expected field at end of `offset_of`
offset_of!(Alpha, Two.0);
offset_of!(Alpha, Two.1); //~ ERROR no field named `1` on enum variant `Alpha::Two`
offset_of!(Alpha, Two.foo); //~ ERROR no field named `foo` on enum variant `Alpha::Two`
offset_of!(Alpha, NonExistent); //~ ERROR no variant named `NonExistent` found for enum `Alpha`
}

26
tests/ui/offset-of/offset-of-enum.stderr
View File

@ -13,7 +13,29 @@ error[E0795]: `One` is an enum variant; expected field at end of `offset_of`
LL | offset_of!(Alpha, One);
| ^^^ enum variant
error: aborting due to 2 previous errors
error[E0609]: no field named `1` on enum variant `Alpha::Two`
--> $DIR/offset-of-enum.rs:14:23
|
LL | offset_of!(Alpha, Two.1);
| ^^^ - ...does not have this field
| |
| this enum variant...
Some errors have detailed explanations: E0573, E0795.
error[E0609]: no field named `foo` on enum variant `Alpha::Two`
--> $DIR/offset-of-enum.rs:15:23
|
LL | offset_of!(Alpha, Two.foo);
| ^^^ --- ...does not have this field
| |
| this enum variant...
error[E0599]: no variant named `NonExistent` found for enum `Alpha`
--> $DIR/offset-of-enum.rs:16:23
|
LL | offset_of!(Alpha, NonExistent);
| ^^^^^^^^^^^ variant not found
error: aborting due to 5 previous errors
Some errors have detailed explanations: E0573, E0599, E0609, E0795.
For more information about an error, try `rustc --explain E0573`.