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Remove some superfluous type parameters from layout.rs.

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Specifically remove V, which can always be VariantIdx, and F, which can
always be Layout.
This commit is contained in:
Michael Benfield
2023-01-20 20:56:16 -08:00
parent 21f6839352
commit 8df27d07ae
7 changed files with 148 additions and 149 deletions
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146
compiler/rustc_abi/src/layout.rs
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@@ -1,11 +1,5 @@
use super::*;
use std::{
borrow::Borrow,
cmp,
fmt::Debug,
iter,
ops::{Bound, Deref},
};
use std::{borrow::Borrow, cmp, iter, ops::Bound};
#[cfg(feature = "randomize")]
use rand::{seq::SliceRandom, SeedableRng};
@@ -33,7 +27,7 @@ pub trait LayoutCalculator {
fn delay_bug(&self, txt: &str);
fn current_data_layout(&self) -> Self::TargetDataLayoutRef;
fn scalar_pair<V: Idx>(&self, a: Scalar, b: Scalar) -> LayoutS<V> {
fn scalar_pair(&self, a: Scalar, b: Scalar) -> LayoutS {
let dl = self.current_data_layout();
let dl = dl.borrow();
let b_align = b.align(dl);
@@ -49,7 +43,7 @@ pub trait LayoutCalculator {
.max_by_key(|niche| niche.available(dl));
LayoutS {
variants: Variants::Single { index: V::new(0) },
variants: Variants::Single { index: VariantIdx::new(0) },
fields: FieldsShape::Arbitrary {
offsets: vec![Size::ZERO, b_offset],
memory_index: vec![0, 1],
@@ -61,13 +55,13 @@ pub trait LayoutCalculator {
}
}
fn univariant<'a, V: Idx, F: Deref<Target = &'a LayoutS<V>> + Debug>(
fn univariant(
&self,
dl: &TargetDataLayout,
fields: &[F],
fields: &[Layout<'_>],
repr: &ReprOptions,
kind: StructKind,
) -> Option<LayoutS<V>> {
) -> Option<LayoutS> {
let pack = repr.pack;
let mut align = if pack.is_some() { dl.i8_align } else { dl.aggregate_align };
let mut inverse_memory_index: Vec<u32> = (0..fields.len() as u32).collect();
@@ -76,17 +70,17 @@ pub trait LayoutCalculator {
let end =
if let StructKind::MaybeUnsized = kind { fields.len() - 1 } else { fields.len() };
let optimizing = &mut inverse_memory_index[..end];
let effective_field_align = |f: &F| {
let effective_field_align = |layout: Layout<'_>| {
if let Some(pack) = pack {
// return the packed alignment in bytes
f.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.
//
// group [u8; 4] with align-4 or [u8; 6] with align-2 fields
f.align.abi.bytes().max(f.size.bytes()).trailing_zeros() as u64
layout.align().abi.bytes().max(layout.size().bytes()).trailing_zeros() as u64
}
};
@@ -111,9 +105,9 @@ pub trait LayoutCalculator {
// Place ZSTs first to avoid "interesting offsets",
// especially with only one or two non-ZST fields.
// Then place largest alignments first, largest niches within an alignment group last
let f = &fields[x as usize];
let niche_size = f.largest_niche.map_or(0, |n| n.available(dl));
(!f.is_zst(), cmp::Reverse(effective_field_align(f)), niche_size)
let f = fields[x as usize];
let niche_size = f.largest_niche().map_or(0, |n| n.available(dl));
(!f.0.is_zst(), cmp::Reverse(effective_field_align(f)), niche_size)
});
}
@@ -123,8 +117,8 @@ pub trait LayoutCalculator {
// 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 as usize];
let niche_size = f.largest_niche.map_or(0, |n| n.available(dl));
let f = fields[x as usize];
let niche_size = f.largest_niche().map_or(0, |n| n.available(dl));
(effective_field_align(f), niche_size)
});
}
@@ -160,15 +154,15 @@ pub trait LayoutCalculator {
));
}
if field.is_unsized() {
if field.0.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);
@@ -176,7 +170,7 @@ pub trait LayoutCalculator {
debug!("univariant offset: {:?} field: {:#?}", offset, field);
offsets[i as usize] = offset;
if let Some(mut niche) = field.largest_niche {
if let Some(mut niche) = field.largest_niche() {
let available = niche.available(dl);
if available > largest_niche_available {
largest_niche_available = available;
@@ -185,7 +179,7 @@ pub trait LayoutCalculator {
}
}
offset = offset.checked_add(field.size, dl)?;
offset = offset.checked_add(field.size(), dl)?;
}
if let Some(repr_align) = repr.align {
align = align.max(AbiAndPrefAlign::new(repr_align));
@@ -205,24 +199,26 @@ pub trait LayoutCalculator {
// Unpack newtype ABIs and find scalar pairs.
if sized && size.bytes() > 0 {
// All other fields must be ZSTs.
let mut non_zst_fields = fields.iter().enumerate().filter(|&(_, f)| !f.is_zst());
let mut non_zst_fields = fields.iter().enumerate().filter(|&(_, f)| !f.0.is_zst());
match (non_zst_fields.next(), non_zst_fields.next(), non_zst_fields.next()) {
// We have exactly one non-ZST field.
(Some((i, field)), None, None) => {
// 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
if offsets[i].bytes() == 0
&& align.abi == field.align().abi
&& size == field.size()
{
match field.abi {
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();
}
_ => {}
}
@@ -231,7 +227,7 @@ pub trait LayoutCalculator {
// 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] {
@@ -239,7 +235,7 @@ pub trait LayoutCalculator {
} else {
((j, b), (i, a))
};
let pair = self.scalar_pair::<V>(a, b);
let pair = self.scalar_pair(a, b);
let pair_offsets = match pair.fields {
FieldsShape::Arbitrary { ref offsets, ref memory_index } => {
assert_eq!(memory_index, &[0, 1]);
@@ -264,11 +260,11 @@ pub trait LayoutCalculator {
_ => {}
}
}
if fields.iter().any(|f| f.abi.is_uninhabited()) {
if fields.iter().any(|f| f.abi().is_uninhabited()) {
abi = Abi::Uninhabited;
}
Some(LayoutS {
variants: Variants::Single { index: V::new(0) },
variants: Variants::Single { index: VariantIdx::new(0) },
fields: FieldsShape::Arbitrary { offsets, memory_index },
abi,
largest_niche,
@@ -277,11 +273,11 @@ pub trait LayoutCalculator {
})
}
fn layout_of_never_type<V: Idx>(&self) -> LayoutS<V> {
fn layout_of_never_type(&self) -> LayoutS {
let dl = self.current_data_layout();
let dl = dl.borrow();
LayoutS {
variants: Variants::Single { index: V::new(0) },
variants: Variants::Single { index: VariantIdx::new(0) },
fields: FieldsShape::Primitive,
abi: Abi::Uninhabited,
largest_niche: None,
@@ -290,18 +286,18 @@ pub trait LayoutCalculator {
}
}
fn layout_of_struct_or_enum<'a, V: Idx, F: Deref<Target = &'a LayoutS<V>> + Debug>(
fn layout_of_struct_or_enum(
&self,
repr: &ReprOptions,
variants: &IndexVec<V, Vec<F>>,
variants: &IndexVec<VariantIdx, Vec<Layout<'_>>>,
is_enum: bool,
is_unsafe_cell: bool,
scalar_valid_range: (Bound<u128>, Bound<u128>),
discr_range_of_repr: impl Fn(i128, i128) -> (Integer, bool),
discriminants: impl Iterator<Item = (V, i128)>,
discriminants: impl Iterator<Item = (VariantIdx, i128)>,
niche_optimize_enum: bool,
always_sized: bool,
) -> Option<LayoutS<V>> {
) -> Option<LayoutS> {
let dl = self.current_data_layout();
let dl = dl.borrow();
@@ -316,9 +312,9 @@ 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: &[F]| {
let uninhabited = fields.iter().any(|f| f.abi.is_uninhabited());
let is_zst = fields.iter().all(|f| f.is_zst());
let absent = |fields: &[Layout<'_>]| {
let uninhabited = fields.iter().any(|f| f.abi().is_uninhabited());
let is_zst = fields.iter().all(|f| f.0.is_zst());
uninhabited && is_zst
};
let (present_first, present_second) = {
@@ -335,7 +331,7 @@ pub trait LayoutCalculator {
}
// If it's a struct, still compute a layout so that we can still compute the
// field offsets.
None => V::new(0),
None => VariantIdx::new(0),
};
let is_struct = !is_enum ||
@@ -439,12 +435,12 @@ 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<V: Idx> {
layout: LayoutS<V>,
variants: IndexVec<V, LayoutS<V>>,
struct TmpLayout {
layout: LayoutS,
variants: IndexVec<VariantIdx, LayoutS>,
}
let calculate_niche_filling_layout = || -> Option<TmpLayout<V>> {
let calculate_niche_filling_layout = || -> Option<TmpLayout> {
if niche_optimize_enum {
return None;
}
@@ -464,15 +460,16 @@ pub trait LayoutCalculator {
Some(st)
})
.collect::<Option<IndexVec<V, _>>>()?;
.collect::<Option<IndexVec<VariantIdx, _>>>()?;
let largest_variant_index = variant_layouts
.iter_enumerated()
.max_by_key(|(_i, layout)| layout.size.bytes())
.map(|(i, _layout)| i)?;
let all_indices = (0..=variants.len() - 1).map(V::new);
let needs_disc = |index: V| index != largest_variant_index && !absent(&variants[index]);
let all_indices = (0..=variants.len() - 1).map(VariantIdx::new);
let needs_disc =
|index: VariantIdx| index != largest_variant_index && !absent(&variants[index]);
let niche_variants = all_indices.clone().find(|v| needs_disc(*v)).unwrap().index()
..=all_indices.rev().find(|v| needs_disc(*v)).unwrap().index();
@@ -482,7 +479,7 @@ pub trait LayoutCalculator {
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 =
@@ -514,7 +511,7 @@ pub trait LayoutCalculator {
match layout.fields {
FieldsShape::Arbitrary { ref mut offsets, .. } => {
for (j, offset) in offsets.iter_mut().enumerate() {
if !variants[i][j].is_zst() {
if !variants[i][j].0.is_zst() {
*offset += this_offset;
}
}
@@ -572,8 +569,8 @@ pub trait LayoutCalculator {
tag: niche_scalar,
tag_encoding: TagEncoding::Niche {
untagged_variant: largest_variant_index,
niche_variants: (V::new(*niche_variants.start())
..=V::new(*niche_variants.end())),
niche_variants: (VariantIdx::new(*niche_variants.start())
..=VariantIdx::new(*niche_variants.end())),
niche_start,
},
tag_field: 0,
@@ -598,7 +595,7 @@ 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() {
@@ -636,7 +633,7 @@ 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);
}
}
}
@@ -655,8 +652,8 @@ pub trait LayoutCalculator {
// Find the first field we can't move later
// to make room for a larger discriminant.
for field in st.fields.index_by_increasing_offset().map(|j| &field_layouts[j]) {
if !field.is_zst() || field.align.abi.bytes() != 1 {
start_align = start_align.min(field.align.abi);
if !field.0.is_zst() || field.align().abi.bytes() != 1 {
start_align = start_align.min(field.align().abi);
break;
}
}
@@ -664,7 +661,7 @@ pub trait LayoutCalculator {
align = align.max(st.align);
Some(st)
})
.collect::<Option<IndexVec<V, _>>>()?;
.collect::<Option<IndexVec<VariantIdx, _>>>()?;
// Align the maximum variant size to the largest alignment.
size = size.align_to(align.abi);
@@ -759,7 +756,7 @@ pub trait LayoutCalculator {
let FieldsShape::Arbitrary { ref offsets, .. } = layout_variant.fields else {
panic!();
};
let mut fields = iter::zip(field_layouts, offsets).filter(|p| !p.0.is_zst());
let mut fields = iter::zip(field_layouts, offsets).filter(|p| !p.0.0.is_zst());
let (field, offset) = match (fields.next(), fields.next()) {
(None, None) => {
common_prim_initialized_in_all_variants = false;
@@ -771,7 +768,7 @@ 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 { .. });
@@ -802,7 +799,7 @@ pub trait LayoutCalculator {
// Common prim might be uninit.
Scalar::Union { value: prim }
};
let pair = self.scalar_pair::<V>(tag, prim_scalar);
let pair = self.scalar_pair(tag, prim_scalar);
let pair_offsets = match pair.fields {
FieldsShape::Arbitrary { ref offsets, ref memory_index } => {
assert_eq!(memory_index, &[0, 1]);
@@ -862,9 +859,8 @@ 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<V>| {
tmp_l.layout.largest_niche.map_or(0, |n| n.available(dl))
};
let niche_size =
|tmp_l: &TmpLayout| 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,
@@ -884,11 +880,11 @@ pub trait LayoutCalculator {
Some(best_layout.layout)
}
fn layout_of_union<'a, V: Idx, F: Deref<Target = &'a LayoutS<V>> + Debug>(
fn layout_of_union(
&self,
repr: &ReprOptions,
variants: &IndexVec<V, Vec<F>>,
) -> Option<LayoutS<V>> {
variants: &IndexVec<VariantIdx, Vec<Layout<'_>>>,
) -> Option<LayoutS> {
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 };
@@ -900,15 +896,15 @@ pub trait LayoutCalculator {
let optimize = !repr.inhibit_union_abi_opt();
let mut size = Size::ZERO;
let mut abi = Abi::Aggregate { sized: true };
let index = V::new(0);
let index = VariantIdx::new(0);
for field in &variants[index] {
assert!(field.is_sized());
align = align.max(field.align);
assert!(field.0.is_sized());
align = align.max(field.align());
// If all non-ZST fields have the same ABI, forward this ABI
if optimize && !field.is_zst() {
if optimize && !field.0.is_zst() {
// Discard valid range information and allow undef
let field_abi = match field.abi {
let field_abi = match field.abi() {
Abi::Scalar(x) => Abi::Scalar(x.to_union()),
Abi::ScalarPair(x, y) => Abi::ScalarPair(x.to_union(), y.to_union()),
Abi::Vector { element: x, count } => {
@@ -926,7 +922,7 @@ pub trait LayoutCalculator {
}
}
size = cmp::max(size, field.size);
size = cmp::max(size, field.size());
}
if let Some(pack) = repr.pack {