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Auto merge of #116269 - Veykril:rustc-abi, r=WaffleLapkin

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Bring back generic parameters for indices in rustc_abi and make it compile on stable

This effectively reverses https://github.com/rust-lang/rust/pull/107163, allowing rust-analyzer to depend on this crate again,

It also moves some glob imports / expands them in the first commit because they made it more difficult for me to reason about things.
This commit is contained in:
bors 2023-10-06 00:03:56 +00:00
commit 2c9b0de8ea
9 changed files with 295 additions and 232 deletions
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1
Cargo.lock
View File

@ -4473,6 +4473,7 @@ dependencies = [
"rustc_data_structures",
"rustc_feature",
"rustc_fs_util",
"rustc_index",
"rustc_macros",
"rustc_serialize",
"rustc_span",

4
compiler/rustc_abi/Cargo.toml
View File

@ -15,7 +15,9 @@ rustc_serialize = { path = "../rustc_serialize", optional = true }
[features]
default = ["nightly", "randomize"]
randomize = ["rand", "rand_xoshiro"]
randomize = ["rand", "rand_xoshiro", "nightly"]
# rust-analyzer depends on this crate and we therefore require it to built on a stable toolchain
# without depending on rustc_data_structures, rustc_macros and rustc_serialize
nightly = [
"rustc_data_structures",
"rustc_index/nightly",

232
compiler/rustc_abi/src/layout.rs
View File

@ -1,21 +1,27 @@
use super::*;
use std::fmt::Write;
use std::fmt::{self, Write};
use std::ops::Deref;
use std::{borrow::Borrow, cmp, iter, ops::Bound};
#[cfg(feature = "randomize")]
use rand::{seq::SliceRandom, SeedableRng};
#[cfg(feature = "randomize")]
use rand_xoshiro::Xoshiro128StarStar;
use rustc_index::Idx;
use tracing::debug;
use crate::{
Abi, AbiAndPrefAlign, Align, FieldsShape, IndexSlice, IndexVec, Integer, LayoutS, Niche,
NonZeroUsize, Primitive, ReprOptions, Scalar, Size, StructKind, TagEncoding, TargetDataLayout,
Variants, WrappingRange,
};
pub trait LayoutCalculator {
type TargetDataLayoutRef: Borrow<TargetDataLayout>;
fn delay_bug(&self, txt: String);
fn current_data_layout(&self) -> Self::TargetDataLayoutRef;
fn scalar_pair(&self, a: Scalar, b: Scalar) -> LayoutS {
fn scalar_pair<FieldIdx: Idx, VariantIdx: Idx>(
&self,
a: Scalar,
b: Scalar,
) -> LayoutS<FieldIdx, VariantIdx> {
let dl = self.current_data_layout();
let dl = dl.borrow();
let b_align = b.align(dl);
@ -31,7 +37,7 @@ pub trait LayoutCalculator {
.max_by_key(|niche| niche.available(dl));
LayoutS {
variants: Variants::Single { index: FIRST_VARIANT },
variants: Variants::Single { index: VariantIdx::new(0) },
fields: FieldsShape::Arbitrary {
offsets: [Size::ZERO, b_offset].into(),
memory_index: [0, 1].into(),
@ -45,13 +51,18 @@ pub trait LayoutCalculator {
}
}
fn univariant(
fn univariant<
'a,
FieldIdx: Idx,
VariantIdx: Idx,
F: Deref<Target = &'a LayoutS<FieldIdx, VariantIdx>> + fmt::Debug,
>(
&self,
dl: &TargetDataLayout,
fields: &IndexSlice<FieldIdx, Layout<'_>>,
fields: &IndexSlice<FieldIdx, F>,
repr: &ReprOptions,
kind: StructKind,
) -> Option<LayoutS> {
) -> Option<LayoutS<FieldIdx, VariantIdx>> {
let layout = univariant(self, dl, fields, repr, kind, NicheBias::Start);
// Enums prefer niches close to the beginning or the end of the variants so that other
// (smaller) data-carrying variants can be packed into the space after/before the niche.
@ -114,11 +125,13 @@ pub trait LayoutCalculator {
layout
}
fn layout_of_never_type(&self) -> LayoutS {
fn layout_of_never_type<FieldIdx: Idx, VariantIdx: Idx>(
&self,
) -> LayoutS<FieldIdx, VariantIdx> {
let dl = self.current_data_layout();
let dl = dl.borrow();
LayoutS {
variants: Variants::Single { index: FIRST_VARIANT },
variants: Variants::Single { index: VariantIdx::new(0) },
fields: FieldsShape::Primitive,
abi: Abi::Uninhabited,
largest_niche: None,
@ -129,10 +142,15 @@ pub trait LayoutCalculator {
}
}
fn layout_of_struct_or_enum(
fn layout_of_struct_or_enum<
'a,
FieldIdx: Idx,
VariantIdx: Idx,
F: Deref<Target = &'a LayoutS<FieldIdx, VariantIdx>> + fmt::Debug,
>(
&self,
repr: &ReprOptions,
variants: &IndexSlice<VariantIdx, IndexVec<FieldIdx, Layout<'_>>>,
variants: &IndexSlice<VariantIdx, IndexVec<FieldIdx, F>>,
is_enum: bool,
is_unsafe_cell: bool,
scalar_valid_range: (Bound<u128>, Bound<u128>),
@ -140,7 +158,7 @@ pub trait LayoutCalculator {
discriminants: impl Iterator<Item = (VariantIdx, i128)>,
dont_niche_optimize_enum: bool,
always_sized: bool,
) -> Option<LayoutS> {
) -> Option<LayoutS<FieldIdx, VariantIdx>> {
let dl = self.current_data_layout();
let dl = dl.borrow();
@ -155,11 +173,11 @@ pub trait LayoutCalculator {
// but *not* an encoding of the discriminant (e.g., a tag value).
// See issue #49298 for more details on the need to leave space
// for non-ZST uninhabited data (mostly partial initialization).
let absent = |fields: &IndexSlice<FieldIdx, Layout<'_>>| {
let uninhabited = fields.iter().any(|f| f.abi().is_uninhabited());
let absent = |fields: &IndexSlice<FieldIdx, F>| {
let uninhabited = fields.iter().any(|f| f.abi.is_uninhabited());
// We cannot ignore alignment; that might lead us to entirely discard a variant and
// produce an enum that is less aligned than it should be!
let is_1zst = fields.iter().all(|f| f.0.is_1zst());
let is_1zst = fields.iter().all(|f| f.is_1zst());
uninhabited && is_1zst
};
let (present_first, present_second) = {
@ -176,7 +194,7 @@ pub trait LayoutCalculator {
}
// If it's a struct, still compute a layout so that we can still compute the
// field offsets.
None => FIRST_VARIANT,
None => VariantIdx::new(0),
};
let is_struct = !is_enum ||
@ -279,12 +297,12 @@ pub trait LayoutCalculator {
// variant layouts, so we can't store them in the
// overall LayoutS. Store the overall LayoutS
// and the variant LayoutSs here until then.
struct TmpLayout {
layout: LayoutS,
variants: IndexVec<VariantIdx, LayoutS>,
struct TmpLayout<FieldIdx: Idx, VariantIdx: Idx> {
layout: LayoutS<FieldIdx, VariantIdx>,
variants: IndexVec<VariantIdx, LayoutS<FieldIdx, VariantIdx>>,
}
let calculate_niche_filling_layout = || -> Option<TmpLayout> {
let calculate_niche_filling_layout = || -> Option<TmpLayout<FieldIdx, VariantIdx>> {
if dont_niche_optimize_enum {
return None;
}
@ -322,13 +340,14 @@ pub trait LayoutCalculator {
let niche_variants = all_indices.clone().find(|v| needs_disc(*v)).unwrap()
..=all_indices.rev().find(|v| needs_disc(*v)).unwrap();
let count = niche_variants.size_hint().1.unwrap() as u128;
let count =
(niche_variants.end().index() as u128 - niche_variants.start().index() as u128) + 1;
// Find the field with the largest niche
let (field_index, niche, (niche_start, niche_scalar)) = variants[largest_variant_index]
.iter()
.enumerate()
.filter_map(|(j, field)| Some((j, field.largest_niche()?)))
.filter_map(|(j, field)| Some((j, field.largest_niche?)))
.max_by_key(|(_, niche)| niche.available(dl))
.and_then(|(j, niche)| Some((j, niche, niche.reserve(dl, count)?)))?;
let niche_offset =
@ -443,7 +462,7 @@ pub trait LayoutCalculator {
let discr_type = repr.discr_type();
let bits = Integer::from_attr(dl, discr_type).size().bits();
for (i, mut val) in discriminants {
if variants[i].iter().any(|f| f.abi().is_uninhabited()) {
if variants[i].iter().any(|f| f.abi.is_uninhabited()) {
continue;
}
if discr_type.is_signed() {
@ -484,7 +503,7 @@ pub trait LayoutCalculator {
if repr.c() {
for fields in variants {
for field in fields {
prefix_align = prefix_align.max(field.align().abi);
prefix_align = prefix_align.max(field.align.abi);
}
}
}
@ -503,9 +522,9 @@ pub trait LayoutCalculator {
// Find the first field we can't move later
// to make room for a larger discriminant.
for field_idx in st.fields.index_by_increasing_offset() {
let field = &field_layouts[FieldIdx::from_usize(field_idx)];
if !field.0.is_1zst() {
start_align = start_align.min(field.align().abi);
let field = &field_layouts[FieldIdx::new(field_idx)];
if !field.is_1zst() {
start_align = start_align.min(field.align.abi);
break;
}
}
@ -587,7 +606,7 @@ pub trait LayoutCalculator {
let tag_mask = ity.size().unsigned_int_max();
let tag = Scalar::Initialized {
value: Int(ity, signed),
value: Primitive::Int(ity, signed),
valid_range: WrappingRange {
start: (min as u128 & tag_mask),
end: (max as u128 & tag_mask),
@ -612,7 +631,7 @@ pub trait LayoutCalculator {
};
// We skip *all* ZST here and later check if we are good in terms of alignment.
// This lets us handle some cases involving aligned ZST.
let mut fields = iter::zip(field_layouts, offsets).filter(|p| !p.0.0.is_zst());
let mut fields = iter::zip(field_layouts, offsets).filter(|p| !p.0.is_zst());
let (field, offset) = match (fields.next(), fields.next()) {
(None, None) => {
common_prim_initialized_in_all_variants = false;
@ -624,7 +643,7 @@ pub trait LayoutCalculator {
break;
}
};
let prim = match field.abi() {
let prim = match field.abi {
Abi::Scalar(scalar) => {
common_prim_initialized_in_all_variants &=
matches!(scalar, Scalar::Initialized { .. });
@ -655,7 +674,7 @@ pub trait LayoutCalculator {
// Common prim might be uninit.
Scalar::Union { value: prim }
};
let pair = self.scalar_pair(tag, prim_scalar);
let pair = self.scalar_pair::<FieldIdx, VariantIdx>(tag, prim_scalar);
let pair_offsets = match pair.fields {
FieldsShape::Arbitrary { ref offsets, ref memory_index } => {
assert_eq!(memory_index.raw, [0, 1]);
@ -663,8 +682,8 @@ pub trait LayoutCalculator {
}
_ => panic!(),
};
if pair_offsets[FieldIdx::from_u32(0)] == Size::ZERO
&& pair_offsets[FieldIdx::from_u32(1)] == *offset
if pair_offsets[FieldIdx::new(0)] == Size::ZERO
&& pair_offsets[FieldIdx::new(1)] == *offset
&& align == pair.align
&& size == pair.size
{
@ -721,8 +740,9 @@ pub trait LayoutCalculator {
// pick the layout with the larger niche; otherwise,
// pick tagged as it has simpler codegen.
use cmp::Ordering::*;
let niche_size =
|tmp_l: &TmpLayout| tmp_l.layout.largest_niche.map_or(0, |n| n.available(dl));
let niche_size = |tmp_l: &TmpLayout<FieldIdx, VariantIdx>| {
tmp_l.layout.largest_niche.map_or(0, |n| n.available(dl))
};
match (tl.layout.size.cmp(&nl.layout.size), niche_size(&tl).cmp(&niche_size(&nl))) {
(Greater, _) => nl,
(Equal, Less) => nl,
@ -742,11 +762,16 @@ pub trait LayoutCalculator {
Some(best_layout.layout)
}
fn layout_of_union(
fn layout_of_union<
'a,
FieldIdx: Idx,
VariantIdx: Idx,
F: Deref<Target = &'a LayoutS<FieldIdx, VariantIdx>> + fmt::Debug,
>(
&self,
repr: &ReprOptions,
variants: &IndexSlice<VariantIdx, IndexVec<FieldIdx, Layout<'_>>>,
) -> Option<LayoutS> {
variants: &IndexSlice<VariantIdx, IndexVec<FieldIdx, F>>,
) -> Option<LayoutS<FieldIdx, VariantIdx>> {
let dl = self.current_data_layout();
let dl = dl.borrow();
let mut align = if repr.pack.is_some() { dl.i8_align } else { dl.aggregate_align };
@ -763,24 +788,24 @@ pub trait LayoutCalculator {
};
let mut size = Size::ZERO;
let only_variant = &variants[FIRST_VARIANT];
let only_variant = &variants[VariantIdx::new(0)];
for field in only_variant {
if field.0.is_unsized() {
if field.is_unsized() {
self.delay_bug("unsized field in union".to_string());
}
align = align.max(field.align());
max_repr_align = max_repr_align.max(field.max_repr_align());
size = cmp::max(size, field.size());
align = align.max(field.align);
max_repr_align = max_repr_align.max(field.max_repr_align);
size = cmp::max(size, field.size);
if field.0.is_zst() {
if field.is_zst() {
// Nothing more to do for ZST fields
continue;
}
if let Ok(common) = common_non_zst_abi_and_align {
// Discard valid range information and allow undef
let field_abi = field.abi().to_union();
let field_abi = field.abi.to_union();
if let Some((common_abi, common_align)) = common {
if common_abi != field_abi {
@ -791,15 +816,14 @@ pub trait LayoutCalculator {
// have the same alignment
if !matches!(common_abi, Abi::Aggregate { .. }) {
assert_eq!(
common_align,
field.align().abi,
common_align, field.align.abi,
"non-Aggregate field with matching ABI but differing alignment"
);
}
}
} else {
// First non-ZST field: record its ABI and alignment
common_non_zst_abi_and_align = Ok(Some((field_abi, field.align().abi)));
common_non_zst_abi_and_align = Ok(Some((field_abi, field.align.abi)));
}
}
}
@ -831,7 +855,7 @@ pub trait LayoutCalculator {
};
Some(LayoutS {
variants: Variants::Single { index: FIRST_VARIANT },
variants: Variants::Single { index: VariantIdx::new(0) },
fields: FieldsShape::Union(NonZeroUsize::new(only_variant.len())?),
abi,
largest_niche: None,
@ -849,14 +873,19 @@ enum NicheBias {
End,
}
fn univariant(
fn univariant<
'a,
FieldIdx: Idx,
VariantIdx: Idx,
F: Deref<Target = &'a LayoutS<FieldIdx, VariantIdx>> + fmt::Debug,
>(
this: &(impl LayoutCalculator + ?Sized),
dl: &TargetDataLayout,
fields: &IndexSlice<FieldIdx, Layout<'_>>,
fields: &IndexSlice<FieldIdx, F>,
repr: &ReprOptions,
kind: StructKind,
niche_bias: NicheBias,
) -> Option<LayoutS> {
) -> Option<LayoutS<FieldIdx, VariantIdx>> {
let pack = repr.pack;
let mut align = if pack.is_some() { dl.i8_align } else { dl.aggregate_align };
let mut max_repr_align = repr.align;
@ -873,9 +902,12 @@ fn univariant(
if repr.can_randomize_type_layout() && cfg!(feature = "randomize") {
#[cfg(feature = "randomize")]
{
use rand::{seq::SliceRandom, SeedableRng};
// `ReprOptions.layout_seed` is a deterministic seed we can use to randomize field
// ordering.
let mut rng = Xoshiro128StarStar::seed_from_u64(repr.field_shuffle_seed.as_u64());
let mut rng = rand_xoshiro::Xoshiro128StarStar::seed_from_u64(
repr.field_shuffle_seed.as_u64(),
);
// Shuffle the ordering of the fields.
optimizing.shuffle(&mut rng);
@ -885,27 +917,27 @@ fn univariant(
// To allow unsizing `&Foo<Type>` -> `&Foo<dyn Trait>`, the layout of the struct must
// not depend on the layout of the tail.
let max_field_align =
fields_excluding_tail.iter().map(|f| f.align().abi.bytes()).max().unwrap_or(1);
fields_excluding_tail.iter().map(|f| f.align.abi.bytes()).max().unwrap_or(1);
let largest_niche_size = fields_excluding_tail
.iter()
.filter_map(|f| f.largest_niche())
.filter_map(|f| f.largest_niche)
.map(|n| n.available(dl))
.max()
.unwrap_or(0);
// Calculates a sort key to group fields by their alignment or possibly some
// size-derived pseudo-alignment.
let alignment_group_key = |layout: Layout<'_>| {
let alignment_group_key = |layout: &F| {
if let Some(pack) = pack {
// Return the packed alignment in bytes.
layout.align().abi.min(pack).bytes()
layout.align.abi.min(pack).bytes()
} else {
// Returns `log2(effective-align)`. This is ok since `pack` applies to all
// fields equally. The calculation assumes that size is an integer multiple of
// align, except for ZSTs.
let align = layout.align().abi.bytes();
let size = layout.size().bytes();
let niche_size = layout.largest_niche().map(|n| n.available(dl)).unwrap_or(0);
let align = layout.align.abi.bytes();
let size = layout.size.bytes();
let niche_size = layout.largest_niche.map(|n| n.available(dl)).unwrap_or(0);
// Group [u8; 4] with align-4 or [u8; 6] with align-2 fields.
let size_as_align = align.max(size).trailing_zeros();
let size_as_align = if largest_niche_size > 0 {
@ -940,9 +972,9 @@ fn univariant(
// u16 to build a 4-byte group so that the u32 can be placed after it without
// padding. This kind of packing can't be achieved by sorting.
optimizing.sort_by_key(|&x| {
let f = fields[x];
let field_size = f.size().bytes();
let niche_size = f.largest_niche().map_or(0, |n| n.available(dl));
let f = &fields[x];
let field_size = f.size.bytes();
let niche_size = f.largest_niche.map_or(0, |n| n.available(dl));
let niche_size_key = match niche_bias {
// large niche first
NicheBias::Start => !niche_size,
@ -950,8 +982,8 @@ fn univariant(
NicheBias::End => niche_size,
};
let inner_niche_offset_key = match niche_bias {
NicheBias::Start => f.largest_niche().map_or(0, |n| n.offset.bytes()),
NicheBias::End => f.largest_niche().map_or(0, |n| {
NicheBias::Start => f.largest_niche.map_or(0, |n| n.offset.bytes()),
NicheBias::End => f.largest_niche.map_or(0, |n| {
!(field_size - n.value.size(dl).bytes() - n.offset.bytes())
}),
};
@ -975,8 +1007,8 @@ fn univariant(
// And put the largest niche in an alignment group at the end
// so it can be used as discriminant in jagged enums
optimizing.sort_by_key(|&x| {
let f = fields[x];
let niche_size = f.largest_niche().map_or(0, |n| n.available(dl));
let f = &fields[x];
let niche_size = f.largest_niche.map_or(0, |n| n.available(dl));
(alignment_group_key(f), niche_size)
});
}
@ -1012,24 +1044,24 @@ fn univariant(
));
}
if field.0.is_unsized() {
if field.is_unsized() {
sized = false;
}
// Invariant: offset < dl.obj_size_bound() <= 1<<61
let field_align = if let Some(pack) = pack {
field.align().min(AbiAndPrefAlign::new(pack))
field.align.min(AbiAndPrefAlign::new(pack))
} else {
field.align()
field.align
};
offset = offset.align_to(field_align.abi);
align = align.max(field_align);
max_repr_align = max_repr_align.max(field.max_repr_align());
max_repr_align = max_repr_align.max(field.max_repr_align);
debug!("univariant offset: {:?} field: {:#?}", offset, field);
offsets[i] = offset;
if let Some(mut niche) = field.largest_niche() {
if let Some(mut niche) = field.largest_niche {
let available = niche.available(dl);
// Pick up larger niches.
let prefer_new_niche = match niche_bias {
@ -1044,7 +1076,7 @@ fn univariant(
}
}
offset = offset.checked_add(field.size(), dl)?;
offset = offset.checked_add(field.size, dl)?;
}
// The unadjusted ABI alignment does not include repr(align), but does include repr(pack).
@ -1068,7 +1100,7 @@ fn univariant(
inverse_memory_index.invert_bijective_mapping()
} else {
debug_assert!(inverse_memory_index.iter().copied().eq(fields.indices()));
inverse_memory_index.into_iter().map(FieldIdx::as_u32).collect()
inverse_memory_index.into_iter().map(|it| it.index() as u32).collect()
};
let size = min_size.align_to(align.abi);
let mut layout_of_single_non_zst_field = None;
@ -1077,7 +1109,7 @@ fn univariant(
if sized && size.bytes() > 0 {
// We skip *all* ZST here and later check if we are good in terms of alignment.
// This lets us handle some cases involving aligned ZST.
let mut non_zst_fields = fields.iter_enumerated().filter(|&(_, f)| !f.0.is_zst());
let mut non_zst_fields = fields.iter_enumerated().filter(|&(_, f)| !f.is_zst());
match (non_zst_fields.next(), non_zst_fields.next(), non_zst_fields.next()) {
// We have exactly one non-ZST field.
@ -1085,18 +1117,17 @@ fn univariant(
layout_of_single_non_zst_field = Some(field);
// Field fills the struct and it has a scalar or scalar pair ABI.
if offsets[i].bytes() == 0 && align.abi == field.align().abi && size == field.size()
{
match field.abi() {
if offsets[i].bytes() == 0 && align.abi == field.align.abi && size == field.size {
match field.abi {
// For plain scalars, or vectors of them, we can't unpack
// newtypes for `#[repr(C)]`, as that affects C ABIs.
Abi::Scalar(_) | Abi::Vector { .. } if optimize => {
abi = field.abi();
abi = field.abi;
}
// But scalar pairs are Rust-specific and get
// treated as aggregates by C ABIs anyway.
Abi::ScalarPair(..) => {
abi = field.abi();
abi = field.abi;
}
_ => {}
}
@ -1105,7 +1136,7 @@ fn univariant(
// Two non-ZST fields, and they're both scalars.
(Some((i, a)), Some((j, b)), None) => {
match (a.abi(), b.abi()) {
match (a.abi, b.abi) {
(Abi::Scalar(a), Abi::Scalar(b)) => {
// Order by the memory placement, not source order.
let ((i, a), (j, b)) = if offsets[i] < offsets[j] {
@ -1113,7 +1144,7 @@ fn univariant(
} else {
((j, b), (i, a))
};
let pair = this.scalar_pair(a, b);
let pair = this.scalar_pair::<FieldIdx, VariantIdx>(a, b);
let pair_offsets = match pair.fields {
FieldsShape::Arbitrary { ref offsets, ref memory_index } => {
assert_eq!(memory_index.raw, [0, 1]);
@ -1121,8 +1152,8 @@ fn univariant(
}
_ => panic!(),
};
if offsets[i] == pair_offsets[FieldIdx::from_usize(0)]
&& offsets[j] == pair_offsets[FieldIdx::from_usize(1)]
if offsets[i] == pair_offsets[FieldIdx::new(0)]
&& offsets[j] == pair_offsets[FieldIdx::new(1)]
&& align == pair.align
&& size == pair.size
{
@ -1138,13 +1169,13 @@ fn univariant(
_ => {}
}
}
if fields.iter().any(|f| f.abi().is_uninhabited()) {
if fields.iter().any(|f| f.abi.is_uninhabited()) {
abi = Abi::Uninhabited;
}
let unadjusted_abi_align = if repr.transparent() {
match layout_of_single_non_zst_field {
Some(l) => l.unadjusted_abi_align(),
Some(l) => l.unadjusted_abi_align,
None => {
// `repr(transparent)` with all ZST fields.
align.abi
@ -1155,7 +1186,7 @@ fn univariant(
};
Some(LayoutS {
variants: Variants::Single { index: FIRST_VARIANT },
variants: Variants::Single { index: VariantIdx::new(0) },
fields: FieldsShape::Arbitrary { offsets, memory_index },
abi,
largest_niche,
@ -1166,17 +1197,22 @@ fn univariant(
})
}
fn format_field_niches(
layout: &LayoutS,
fields: &IndexSlice<FieldIdx, Layout<'_>>,
fn format_field_niches<
'a,
FieldIdx: Idx,
VariantIdx: Idx,
F: Deref<Target = &'a LayoutS<FieldIdx, VariantIdx>> + fmt::Debug,
>(
layout: &LayoutS<FieldIdx, VariantIdx>,
fields: &IndexSlice<FieldIdx, F>,
dl: &TargetDataLayout,
) -> String {
let mut s = String::new();
for i in layout.fields.index_by_increasing_offset() {
let offset = layout.fields.offset(i);
let f = fields[i.into()];
write!(s, "[o{}a{}s{}", offset.bytes(), f.align().abi.bytes(), f.size().bytes()).unwrap();
if let Some(n) = f.largest_niche() {
let f = &fields[FieldIdx::new(i)];
write!(s, "[o{}a{}s{}", offset.bytes(), f.align.abi.bytes(), f.size.bytes()).unwrap();
if let Some(n) = f.largest_niche {
write!(
s,
" n{}b{}s{}",

171
compiler/rustc_abi/src/lib.rs
View File

@ -1,23 +1,22 @@
#![cfg_attr(feature = "nightly", feature(step_trait, rustc_attrs, min_specialization))]
#![cfg_attr(feature = "nightly", feature(step_trait))]
#![cfg_attr(feature = "nightly", allow(internal_features))]
use std::fmt;
#[cfg(feature = "nightly")]
use std::iter::Step;
use std::num::{NonZeroUsize, ParseIntError};
use std::ops::{Add, AddAssign, Mul, RangeInclusive, Sub};
use std::str::FromStr;
use bitflags::bitflags;
use rustc_data_structures::intern::Interned;
use rustc_data_structures::stable_hasher::Hash64;
use rustc_index::{Idx, IndexSlice, IndexVec};
#[cfg(feature = "nightly")]
use rustc_data_structures::stable_hasher::StableOrd;
use rustc_index::{IndexSlice, IndexVec};
#[cfg(feature = "nightly")]
use rustc_macros::HashStable_Generic;
#[cfg(feature = "nightly")]
use rustc_macros::{Decodable, Encodable};
#[cfg(feature = "nightly")]
use std::iter::Step;
mod layout;
@ -28,9 +27,6 @@ pub use layout::LayoutCalculator;
/// instead of implementing everything in `rustc_middle`.
pub trait HashStableContext {}
use Integer::*;
use Primitive::*;
bitflags! {
#[derive(Default)]
#[cfg_attr(feature = "nightly", derive(Encodable, Decodable, HashStable_Generic))]
@ -78,6 +74,7 @@ pub struct ReprOptions {
pub align: Option<Align>,
pub pack: Option<Align>,
pub flags: ReprFlags,
#[cfg(feature = "randomize")]
/// The seed to be used for randomizing a type's layout
///
/// Note: This could technically be a `Hash128` which would
@ -85,7 +82,7 @@ pub struct ReprOptions {
/// hash without loss, but it does pay the price of being larger.
/// Everything's a tradeoff, a 64-bit seed should be sufficient for our
/// purposes (primarily `-Z randomize-layout`)
pub field_shuffle_seed: Hash64,
pub field_shuffle_seed: rustc_data_structures::stable_hasher::Hash64,
}
impl ReprOptions {
@ -342,6 +339,7 @@ impl TargetDataLayout {
#[inline]
pub fn ptr_sized_integer(&self) -> Integer {
use Integer::*;
match self.pointer_size.bits() {
16 => I16,
32 => I32,
@ -786,6 +784,7 @@ pub enum Integer {
impl Integer {
#[inline]
pub fn size(self) -> Size {
use Integer::*;
match self {
I8 => Size::from_bytes(1),
I16 => Size::from_bytes(2),
@ -806,6 +805,7 @@ impl Integer {
}
pub fn align<C: HasDataLayout>(self, cx: &C) -> AbiAndPrefAlign {
use Integer::*;
let dl = cx.data_layout();
match self {
@ -820,6 +820,7 @@ impl Integer {
/// Returns the largest signed value that can be represented by this Integer.
#[inline]
pub fn signed_max(self) -> i128 {
use Integer::*;
match self {
I8 => i8::MAX as i128,
I16 => i16::MAX as i128,
@ -832,6 +833,7 @@ impl Integer {
/// Finds the smallest Integer type which can represent the signed value.
#[inline]
pub fn fit_signed(x: i128) -> Integer {
use Integer::*;
match x {
-0x0000_0000_0000_0080..=0x0000_0000_0000_007f => I8,
-0x0000_0000_0000_8000..=0x0000_0000_0000_7fff => I16,
@ -844,6 +846,7 @@ impl Integer {
/// Finds the smallest Integer type which can represent the unsigned value.
#[inline]
pub fn fit_unsigned(x: u128) -> Integer {
use Integer::*;
match x {
0..=0x0000_0000_0000_00ff => I8,
0..=0x0000_0000_0000_ffff => I16,
@ -855,6 +858,7 @@ impl Integer {
/// Finds the smallest integer with the given alignment.
pub fn for_align<C: HasDataLayout>(cx: &C, wanted: Align) -> Option<Integer> {
use Integer::*;
let dl = cx.data_layout();
[I8, I16, I32, I64, I128].into_iter().find(|&candidate| {
@ -864,6 +868,7 @@ impl Integer {
/// Find the largest integer with the given alignment or less.
pub fn approximate_align<C: HasDataLayout>(cx: &C, wanted: Align) -> Integer {
use Integer::*;
let dl = cx.data_layout();
// FIXME(eddyb) maybe include I128 in the future, when it works everywhere.
@ -909,6 +914,7 @@ pub enum Primitive {
impl Primitive {
pub fn size<C: HasDataLayout>(self, cx: &C) -> Size {
use Primitive::*;
let dl = cx.data_layout();
match self {
@ -923,6 +929,7 @@ impl Primitive {
}
pub fn align<C: HasDataLayout>(self, cx: &C) -> AbiAndPrefAlign {
use Primitive::*;
let dl = cx.data_layout();
match self {
@ -1027,10 +1034,11 @@ pub enum Scalar {
impl Scalar {
#[inline]
pub fn is_bool(&self) -> bool {
use Integer::*;
matches!(
self,
Scalar::Initialized {
value: Int(I8, false),
value: Primitive::Int(I8, false),
valid_range: WrappingRange { start: 0, end: 1 }
}
)
@ -1095,36 +1103,11 @@ impl Scalar {
}
}
rustc_index::newtype_index! {
/// The *source-order* index of a field in a variant.
///
/// This is how most code after type checking refers to fields, rather than
/// using names (as names have hygiene complications and more complex lookup).
///
/// Particularly for `repr(Rust)` types, this may not be the same as *layout* order.
/// (It is for `repr(C)` `struct`s, however.)
///
/// For example, in the following types,
/// ```rust
/// # enum Never {}
/// # #[repr(u16)]
/// enum Demo1 {
/// Variant0 { a: Never, b: i32 } = 100,
/// Variant1 { c: u8, d: u64 } = 10,
/// }
/// struct Demo2 { e: u8, f: u16, g: u8 }
/// ```
/// `b` is `FieldIdx(1)` in `VariantIdx(0)`,
/// `d` is `FieldIdx(1)` in `VariantIdx(1)`, and
/// `f` is `FieldIdx(1)` in `VariantIdx(0)`.
#[derive(HashStable_Generic)]
pub struct FieldIdx {}
}
// NOTE: This struct is generic over the FieldIdx for rust-analyzer usage.
/// Describes how the fields of a type are located in memory.
#[derive(PartialEq, Eq, Hash, Clone, Debug)]
#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
pub enum FieldsShape {
pub enum FieldsShape<FieldIdx: Idx> {
/// Scalar primitives and `!`, which never have fields.
Primitive,
@ -1164,7 +1147,7 @@ pub enum FieldsShape {
},
}
impl FieldsShape {
impl<FieldIdx: Idx> FieldsShape<FieldIdx> {
#[inline]
pub fn count(&self) -> usize {
match *self {
@ -1190,7 +1173,7 @@ impl FieldsShape {
assert!(i < count, "tried to access field {i} of array with {count} fields");
stride * i
}
FieldsShape::Arbitrary { ref offsets, .. } => offsets[FieldIdx::from_usize(i)],
FieldsShape::Arbitrary { ref offsets, .. } => offsets[FieldIdx::new(i)],
}
}
@ -1202,7 +1185,7 @@ impl FieldsShape {
}
FieldsShape::Union(_) | FieldsShape::Array { .. } => i,
FieldsShape::Arbitrary { ref memory_index, .. } => {
memory_index[FieldIdx::from_usize(i)].try_into().unwrap()
memory_index[FieldIdx::new(i)].try_into().unwrap()
}
}
}
@ -1218,7 +1201,7 @@ impl FieldsShape {
if let FieldsShape::Arbitrary { ref memory_index, .. } = *self {
if use_small {
for (field_idx, &mem_idx) in memory_index.iter_enumerated() {
inverse_small[mem_idx as usize] = field_idx.as_u32() as u8;
inverse_small[mem_idx as usize] = field_idx.index() as u8;
}
} else {
inverse_big = memory_index.invert_bijective_mapping();
@ -1231,7 +1214,7 @@ impl FieldsShape {
if use_small {
inverse_small[i] as usize
} else {
inverse_big[i as u32].as_usize()
inverse_big[i as u32].index()
}
}
})
@ -1374,9 +1357,10 @@ impl Abi {
}
}
// NOTE: This struct is generic over the FieldIdx and VariantIdx for rust-analyzer usage.
#[derive(PartialEq, Eq, Hash, Clone, Debug)]
#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
pub enum Variants {
pub enum Variants<FieldIdx: Idx, VariantIdx: Idx> {
/// Single enum variants, structs/tuples, unions, and all non-ADTs.
Single { index: VariantIdx },
@ -1388,15 +1372,16 @@ pub enum Variants {
/// For enums, the tag is the sole field of the layout.
Multiple {
tag: Scalar,
tag_encoding: TagEncoding,
tag_encoding: TagEncoding<VariantIdx>,
tag_field: usize,
variants: IndexVec<VariantIdx, LayoutS>,
variants: IndexVec<VariantIdx, LayoutS<FieldIdx, VariantIdx>>,
},
}
// NOTE: This struct is generic over the VariantIdx for rust-analyzer usage.
#[derive(PartialEq, Eq, Hash, Clone, Debug)]
#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
pub enum TagEncoding {
pub enum TagEncoding<VariantIdx: Idx> {
/// The tag directly stores the discriminant, but possibly with a smaller layout
/// (so converting the tag to the discriminant can require sign extension).
Direct,
@ -1504,29 +1489,12 @@ impl Niche {
}
}
rustc_index::newtype_index! {
/// The *source-order* index of a variant in a type.
///
/// For enums, these are always `0..variant_count`, regardless of any
/// custom discriminants that may have been defined, and including any
/// variants that may end up uninhabited due to field types. (Some of the
/// variants may not be present in a monomorphized ABI [`Variants`], but
/// those skipped variants are always counted when determining the *index*.)
///
/// `struct`s, `tuples`, and `unions`s are considered to have a single variant
/// with variant index zero, aka [`FIRST_VARIANT`].
#[derive(HashStable_Generic)]
pub struct VariantIdx {
/// Equivalent to `VariantIdx(0)`.
const FIRST_VARIANT = 0;
}
}
// NOTE: This struct is generic over the FieldIdx and VariantIdx for rust-analyzer usage.
#[derive(PartialEq, Eq, Hash, Clone)]
#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
pub struct LayoutS {
pub struct LayoutS<FieldIdx: Idx, VariantIdx: Idx> {
/// Says where the fields are located within the layout.
pub fields: FieldsShape,
pub fields: FieldsShape<FieldIdx>,
/// Encodes information about multi-variant layouts.
/// Even with `Multiple` variants, a layout still has its own fields! Those are then
@ -1535,7 +1503,7 @@ pub struct LayoutS {
///
/// To access all fields of this layout, both `fields` and the fields of the active variant
/// must be taken into account.
pub variants: Variants,
pub variants: Variants<FieldIdx, VariantIdx>,
/// The `abi` defines how this data is passed between functions, and it defines
/// value restrictions via `valid_range`.
@ -1564,13 +1532,13 @@ pub struct LayoutS {
pub unadjusted_abi_align: Align,
}
impl LayoutS {
impl<FieldIdx: Idx, VariantIdx: Idx> LayoutS<FieldIdx, VariantIdx> {
pub fn scalar<C: HasDataLayout>(cx: &C, scalar: Scalar) -> Self {
let largest_niche = Niche::from_scalar(cx, Size::ZERO, scalar);
let size = scalar.size(cx);
let align = scalar.align(cx);
LayoutS {
variants: Variants::Single { index: FIRST_VARIANT },
variants: Variants::Single { index: VariantIdx::new(0) },
fields: FieldsShape::Primitive,
abi: Abi::Scalar(scalar),
largest_niche,
@ -1582,7 +1550,11 @@ impl LayoutS {
}
}
impl fmt::Debug for LayoutS {
impl<FieldIdx: Idx, VariantIdx: Idx> fmt::Debug for LayoutS<FieldIdx, VariantIdx>
where
FieldsShape<FieldIdx>: fmt::Debug,
Variants<FieldIdx, VariantIdx>: fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
// This is how `Layout` used to print before it become
// `Interned<LayoutS>`. We print it like this to avoid having to update
@ -1610,61 +1582,6 @@ impl fmt::Debug for LayoutS {
}
}
#[derive(Copy, Clone, PartialEq, Eq, Hash, HashStable_Generic)]
#[rustc_pass_by_value]
pub struct Layout<'a>(pub Interned<'a, LayoutS>);
impl<'a> fmt::Debug for Layout<'a> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
// See comment on `<LayoutS as Debug>::fmt` above.
self.0.0.fmt(f)
}
}
impl<'a> Layout<'a> {
pub fn fields(self) -> &'a FieldsShape {
&self.0.0.fields
}
pub fn variants(self) -> &'a Variants {
&self.0.0.variants
}
pub fn abi(self) -> Abi {
self.0.0.abi
}
pub fn largest_niche(self) -> Option<Niche> {
self.0.0.largest_niche
}
pub fn align(self) -> AbiAndPrefAlign {
self.0.0.align
}
pub fn size(self) -> Size {
self.0.0.size
}
pub fn max_repr_align(self) -> Option<Align> {
self.0.0.max_repr_align
}
pub fn unadjusted_abi_align(self) -> Align {
self.0.0.unadjusted_abi_align
}
/// Whether the layout is from a type that implements [`std::marker::PointerLike`].
///
/// Currently, that means that the type is pointer-sized, pointer-aligned,
/// and has a scalar ABI.
pub fn is_pointer_like(self, data_layout: &TargetDataLayout) -> bool {
self.size() == data_layout.pointer_size
&& self.align().abi == data_layout.pointer_align.abi
&& matches!(self.abi(), Abi::Scalar(..))
}
}
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum PointerKind {
/// Shared reference. `frozen` indicates the absence of any `UnsafeCell`.
@ -1684,7 +1601,7 @@ pub struct PointeeInfo {
pub safe: Option<PointerKind>,
}
impl LayoutS {
impl<FieldIdx: Idx, VariantIdx: Idx> LayoutS<FieldIdx, VariantIdx> {
/// Returns `true` if the layout corresponds to an unsized type.
#[inline]
pub fn is_unsized(&self) -> bool {

2
compiler/rustc_middle/src/arena.rs
View File

@ -8,7 +8,7 @@
macro_rules! arena_types {
($macro:path) => (
$macro!([
[] layout: rustc_target::abi::LayoutS,
[] layout: rustc_target::abi::LayoutS<rustc_target::abi::FieldIdx, rustc_target::abi::VariantIdx>,
[] fn_abi: rustc_target::abi::call::FnAbi<'tcx, rustc_middle::ty::Ty<'tcx>>,
// AdtDef are interned and compared by address
[decode] adt_def: rustc_middle::ty::AdtDefData,

4
compiler/rustc_middle/src/ty/context.rs
View File

@ -152,7 +152,7 @@ pub struct CtxtInterners<'tcx> {
const_: InternedSet<'tcx, ConstData<'tcx>>,
const_allocation: InternedSet<'tcx, Allocation>,
bound_variable_kinds: InternedSet<'tcx, List<ty::BoundVariableKind>>,
layout: InternedSet<'tcx, LayoutS>,
layout: InternedSet<'tcx, LayoutS<FieldIdx, VariantIdx>>,
adt_def: InternedSet<'tcx, AdtDefData>,
external_constraints: InternedSet<'tcx, ExternalConstraintsData<'tcx>>,
predefined_opaques_in_body: InternedSet<'tcx, PredefinedOpaquesData<'tcx>>,
@ -1521,7 +1521,7 @@ direct_interners! {
region: pub(crate) intern_region(RegionKind<'tcx>): Region -> Region<'tcx>,
const_: intern_const(ConstData<'tcx>): Const -> Const<'tcx>,
const_allocation: pub mk_const_alloc(Allocation): ConstAllocation -> ConstAllocation<'tcx>,
layout: pub mk_layout(LayoutS): Layout -> Layout<'tcx>,
layout: pub mk_layout(LayoutS<FieldIdx, VariantIdx>): Layout -> Layout<'tcx>,
adt_def: pub mk_adt_def_from_data(AdtDefData): AdtDef -> AdtDef<'tcx>,
external_constraints: pub mk_external_constraints(ExternalConstraintsData<'tcx>):
ExternalConstraints -> ExternalConstraints<'tcx>,

1
compiler/rustc_target/Cargo.toml
View File

@ -14,6 +14,7 @@ rustc_feature = { path = "../rustc_feature" }
rustc_macros = { path = "../rustc_macros" }
rustc_serialize = { path = "../rustc_serialize" }
rustc_span = { path = "../rustc_span" }
rustc_index = { path = "../rustc_index" }
[dependencies.object]
version = "0.32.0"

110
compiler/rustc_target/src/abi/mod.rs
View File

@ -1,3 +1,4 @@
use rustc_data_structures::intern::Interned;
pub use Integer::*;
pub use Primitive::*;
@ -18,6 +19,111 @@ impl ToJson for Endian {
}
}
rustc_index::newtype_index! {
/// The *source-order* index of a field in a variant.
///
/// This is how most code after type checking refers to fields, rather than
/// using names (as names have hygiene complications and more complex lookup).
///
/// Particularly for `repr(Rust)` types, this may not be the same as *layout* order.
/// (It is for `repr(C)` `struct`s, however.)
///
/// For example, in the following types,
/// ```rust
/// # enum Never {}
/// # #[repr(u16)]
/// enum Demo1 {
/// Variant0 { a: Never, b: i32 } = 100,
/// Variant1 { c: u8, d: u64 } = 10,
/// }
/// struct Demo2 { e: u8, f: u16, g: u8 }
/// ```
/// `b` is `FieldIdx(1)` in `VariantIdx(0)`,
/// `d` is `FieldIdx(1)` in `VariantIdx(1)`, and
/// `f` is `FieldIdx(1)` in `VariantIdx(0)`.
#[derive(HashStable_Generic)]
pub struct FieldIdx {}
}
rustc_index::newtype_index! {
/// The *source-order* index of a variant in a type.
///
/// For enums, these are always `0..variant_count`, regardless of any
/// custom discriminants that may have been defined, and including any
/// variants that may end up uninhabited due to field types. (Some of the
/// variants may not be present in a monomorphized ABI [`Variants`], but
/// those skipped variants are always counted when determining the *index*.)
///
/// `struct`s, `tuples`, and `unions`s are considered to have a single variant
/// with variant index zero, aka [`FIRST_VARIANT`].
#[derive(HashStable_Generic)]
pub struct VariantIdx {
/// Equivalent to `VariantIdx(0)`.
const FIRST_VARIANT = 0;
}
}
#[derive(Copy, Clone, PartialEq, Eq, Hash, HashStable_Generic)]
#[rustc_pass_by_value]
pub struct Layout<'a>(pub Interned<'a, LayoutS<FieldIdx, VariantIdx>>);
impl<'a> fmt::Debug for Layout<'a> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
// See comment on `<LayoutS as Debug>::fmt` above.
self.0.0.fmt(f)
}
}
impl<'a> Deref for Layout<'a> {
type Target = &'a LayoutS<FieldIdx, VariantIdx>;
fn deref(&self) -> &&'a LayoutS<FieldIdx, VariantIdx> {
&self.0.0
}
}
impl<'a> Layout<'a> {
pub fn fields(self) -> &'a FieldsShape<FieldIdx> {
&self.0.0.fields
}
pub fn variants(self) -> &'a Variants<FieldIdx, VariantIdx> {
&self.0.0.variants
}
pub fn abi(self) -> Abi {
self.0.0.abi
}
pub fn largest_niche(self) -> Option<Niche> {
self.0.0.largest_niche
}
pub fn align(self) -> AbiAndPrefAlign {
self.0.0.align
}
pub fn size(self) -> Size {
self.0.0.size
}
pub fn max_repr_align(self) -> Option<Align> {
self.0.0.max_repr_align
}
pub fn unadjusted_abi_align(self) -> Align {
self.0.0.unadjusted_abi_align
}
/// Whether the layout is from a type that implements [`std::marker::PointerLike`].
///
/// Currently, that means that the type is pointer-sized, pointer-aligned,
/// and has a scalar ABI.
pub fn is_pointer_like(self, data_layout: &TargetDataLayout) -> bool {
self.size() == data_layout.pointer_size
&& self.align().abi == data_layout.pointer_align.abi
&& matches!(self.abi(), Abi::Scalar(..))
}
}
/// The layout of a type, alongside the type itself.
/// Provides various type traversal APIs (e.g., recursing into fields).
///
@ -42,8 +148,8 @@ impl<'a, Ty: fmt::Display> fmt::Debug for TyAndLayout<'a, Ty> {
}
impl<'a, Ty> Deref for TyAndLayout<'a, Ty> {
type Target = &'a LayoutS;
fn deref(&self) -> &&'a LayoutS {
type Target = &'a LayoutS<FieldIdx, VariantIdx>;
fn deref(&self) -> &&'a LayoutS<FieldIdx, VariantIdx> {
&self.layout.0.0
}
}

2
compiler/rustc_ty_utils/src/layout.rs
View File

@ -85,7 +85,7 @@ fn univariant_uninterned<'tcx>(
fields: &IndexSlice<FieldIdx, Layout<'_>>,
repr: &ReprOptions,
kind: StructKind,
) -> Result<LayoutS, &'tcx LayoutError<'tcx>> {
) -> Result<LayoutS<FieldIdx, VariantIdx>, &'tcx LayoutError<'tcx>> {
let dl = cx.data_layout();
let pack = repr.pack;
if pack.is_some() && repr.align.is_some() {