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Enums MVP. #819

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eb18850
Enums MVP.
ElectronicRU Dec 7, 2021
a36fb0f
Make Option<bool> also work while we're at it.
ElectronicRU Dec 7, 2021
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327 changes: 276 additions & 51 deletions crates/rustc_codegen_spirv/src/abi.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,8 +12,8 @@ use rustc_middle::ty::layout::{FnAbiOf, LayoutOf, TyAndLayout};
use rustc_middle::ty::query::{ExternProviders, Providers};
use rustc_middle::ty::subst::SubstsRef;
use rustc_middle::ty::{
self, Const, FloatTy, GeneratorSubsts, IntTy, ParamEnv, PolyFnSig, Ty, TyCtxt, TyKind,
TypeAndMut, UintTy,
self, layout::LayoutError, AdtDef, Const, FloatTy, GeneratorSubsts, IntTy, ParamEnv, PolyFnSig,
Ty, TyCtxt, TyKind, TypeAndMut, UintTy, VariantDef,
};
use rustc_middle::{bug, span_bug};
use rustc_span::def_id::DefId;
Expand Down Expand Up @@ -150,21 +150,192 @@ pub(crate) fn provide(providers: &mut Providers) {
let TyAndLayout { ty, mut layout } =
(rustc_interface::DEFAULT_QUERY_PROVIDERS.layout_of)(tcx, key)?;

#[allow(clippy::match_like_matches_macro)]
let hide_niche = match ty.kind() {
ty::Bool => true,
_ => false,
match (&layout.variants, &layout.abi, &layout.fields, ty.kind()) {
(
Variants::Multiple { .. },
Abi::Aggregate { .. },
&FieldsShape::Arbitrary { .. },
TyKind::Adt(def, substs),
) => {
let mut our_layout = clone_layout(layout);
deoverlay_enum_fields(tcx, ty, key.param_env, def, substs, &mut our_layout)?;
layout = tcx.intern_layout(our_layout);
}
(_, _, _, ty::Bool) => {
layout = tcx.intern_layout(Layout {
largest_niche: None,
..clone_layout(layout)
});
}
_ => {}
}

Ok(TyAndLayout { ty, layout })
};
}

fn deoverlay_enum_fields<'tcx>(
tcx: TyCtxt<'tcx>,
ty: Ty<'tcx>,
param_env: ParamEnv<'tcx>,
def: &AdtDef,
substs: SubstsRef<'tcx>,
layout: &mut Layout,
) -> Result<(), LayoutError<'tcx>> {
if let Variants::Multiple {
ref tag_encoding,
ref mut variants,
..
} = layout.variants
{
let mut niche = match tag_encoding {
TagEncoding::Niche {
dataful_variant, ..
} => Some((*dataful_variant, layout.fields.offset(0))),

TagEncoding::Direct => {
assert_eq!(Size::ZERO, layout.fields.offset(0));
None
}
};

if hide_niche {
layout = tcx.arena.alloc(Layout {
largest_niche: None,
..clone_layout(layout)
});
let mut field_cache = vec![];

for (index, variant_layout) in variants.iter_enumerated_mut() {
#[allow(clippy::map_err_ignore)]
deoverlay_variant(
tcx,
param_env,
&def.variants[index],
substs,
&mut field_cache,
index,
variant_layout,
&mut layout.size,
&mut niche,
def.repr.c(),
)
.map_err(|_| LayoutError::Unknown(ty))?;
}

Ok(TyAndLayout { ty, layout })
if let Some((_, offset)) = niche {
if let FieldsShape::Arbitrary {
ref mut offsets, ..
} = layout.fields
{
offsets[0] = offset;
} else {
bug!();
}
}
} else {
bug!();
}
Ok(())
}

#[allow(clippy::too_many_arguments)]
fn deoverlay_variant<'tcx>(
tcx: TyCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
def: &VariantDef,
substs: SubstsRef<'tcx>,
field_cache: &mut Vec<(Size, VariantIdx, TyAndLayout<'tcx>)>,
index: VariantIdx,
layout: &mut Layout,
size: &mut Size,
niche: &mut Option<(VariantIdx, Size)>,
is_c: bool,
) -> Result<(), ()> {
let find_field_by_offset_or_type =
|offset, ty, field_cache: &mut Vec<(Size, VariantIdx, TyAndLayout<'tcx>)>, dry: bool| {
match field_cache[..].binary_search_by(|&(foff, _, _)| foff.cmp(&offset)) {
Ok(idx) => {
if field_cache[idx].2 == ty && field_cache[idx].1 != index {
return Some(offset);
}
}
Err(idx) => {
let prev_fits =
idx == 0 || field_cache[idx - 1].0 + field_cache[idx - 1].2.size <= offset;
let next_fits =
idx == field_cache.len() || field_cache[idx].0 >= offset + ty.size;
if prev_fits && next_fits {
if !dry {
field_cache.insert(idx, (offset, index, ty));
}
return Some(offset);
}
}
}
if !is_c {
if let Some((offset, _, _)) = field_cache
.iter()
.find(|&(_, varidx, otherty)| *varidx != index && *otherty == ty)
{
return Some(*offset);
}
}
None
};
let mut add_at_end =
|i: usize,
ty: TyAndLayout<'tcx>,
field_cache: &mut Vec<(Size, VariantIdx, TyAndLayout<'tcx>)>| {
let offset = size.align_to(ty.align.abi);
if !is_c {
field_cache.push((offset, index, ty));
*size = offset + ty.size;
Ok(offset)
} else {
tcx.sess.span_err(
tcx.def_span(def.fields[i].did),
"Failed to make repr(C) layout: field overlaps a different data type",
);
Err(())
}
};
let mut find_or_add = |a, aofs, aty| {
find_field_by_offset_or_type(aofs, aty, field_cache, false)
.map_or_else(|| add_at_end(a, aty, field_cache), Ok)
};
let mut assign_and_check = |offset: &mut Size, newval| {
if Some((index, *offset)) == *niche {
*niche = Some((index, newval));
}
*offset = newval;
};
let (offsets, memory_index) = if let FieldsShape::Arbitrary {
ref mut offsets,
ref mut memory_index,
} = layout.fields
{
(offsets, memory_index)
} else {
bug!("univariant has FieldsShape: {:?}", layout.fields);
};
// ZST fields can happily live at whatever offset
let non_zst = (0..offsets.len())
.map(|i| (i, def.fields[i].ty(tcx, substs)))
.map(|(i, ty)| (i, tcx.layout_of(param_env.and(ty)).unwrap()))
.filter(|(_, ty)| !ty.is_zst());

match layout.abi {
// Apparently you're supposed to reserve space for non-ZST uninhabited fields
Abi::Aggregate { .. } => {
for (i, ty) in non_zst {
let newofs = find_or_add(i, offsets[i], ty)?;
assign_and_check(&mut offsets[i], newofs);
}
// rebuild memory_index
let mut new_memindex: Vec<_> = (0..offsets.len() as u32).collect();
new_memindex[..].sort_by_key(|i| offsets[*i as usize]);
*memory_index = new_memindex;
}
_ => bug!("non-Aggregate variant in Aggregate enum: {:?}", def),
}

Ok(())
}

pub(crate) fn provide_extern(providers: &mut ExternProviders) {
Expand Down Expand Up @@ -359,15 +530,11 @@ impl<'tcx> ConvSpirvType<'tcx> for TyAndLayout<'tcx> {
// `ScalarPair`.
// There's a few layers that we go through here. First we inspect layout.abi, then if relevant, layout.fields, etc.
match self.abi {
Abi::Uninhabited => SpirvType::Adt {
def_id: def_id_for_spirv_type_adt(*self),
size: Some(Size::ZERO),
align: Align::from_bytes(0).unwrap(),
field_types: Vec::new(),
field_offsets: Vec::new(),
field_names: None,
}
.def_with_name(cx, span, TyLayoutNameKey::from(*self)),
Abi::Uninhabited => SpirvType::zst(def_id_for_spirv_type_adt(*self)).def_with_name(
cx,
span,
TyLayoutNameKey::from(*self),
),
Abi::Scalar(ref scalar) => trans_scalar(cx, span, *self, scalar, Size::ZERO),
Abi::ScalarPair(ref a, ref b) => {
// Note: We can't use auto_struct_layout here because the spirv types here might be undefined due to
Expand All @@ -391,6 +558,7 @@ impl<'tcx> ConvSpirvType<'tcx> for TyAndLayout<'tcx> {
}
}
SpirvType::Adt {
is_enum: false,
def_id: def_id_for_spirv_type_adt(*self),
size,
align: self.align.abi,
Expand Down Expand Up @@ -559,15 +727,11 @@ fn dig_scalar_pointee<'tcx>(

fn trans_aggregate<'tcx>(cx: &CodegenCx<'tcx>, span: Span, ty: TyAndLayout<'tcx>) -> Word {
fn create_zst<'tcx>(cx: &CodegenCx<'tcx>, span: Span, ty: TyAndLayout<'tcx>) -> Word {
SpirvType::Adt {
def_id: def_id_for_spirv_type_adt(ty),
size: Some(Size::ZERO),
align: Align::from_bytes(0).unwrap(),
field_types: Vec::new(),
field_offsets: Vec::new(),
field_names: None,
}
.def_with_name(cx, span, TyLayoutNameKey::from(ty))
SpirvType::zst(def_id_for_spirv_type_adt(ty)).def_with_name(
cx,
span,
TyLayoutNameKey::from(ty),
)
}
match ty.fields {
FieldsShape::Primitive => span_bug!(
Expand Down Expand Up @@ -617,11 +781,78 @@ fn trans_aggregate<'tcx>(cx: &CodegenCx<'tcx>, span: Span, ty: TyAndLayout<'tcx>
.def(span, cx)
}
}
FieldsShape::Arbitrary {
offsets: _,
memory_index: _,
} => trans_struct(cx, span, ty),
FieldsShape::Arbitrary { .. } => {
if let (Variants::Multiple { .. }, TyKind::Adt(_, _)) = (&ty.variants, ty.ty.kind()) {
trans_enum(cx, span, ty)
} else {
trans_struct(cx, span, ty)
}
}
}
}

fn trans_enum<'tcx>(cx: &CodegenCx<'tcx>, span: Span, ty: TyAndLayout<'tcx>) -> Word {
let (variants, tag) = if let Variants::Multiple {
ref variants,
ref tag,
..
} = ty.variants
{
(variants, tag)
} else {
unreachable!();
};
let tag_offset = ty.fields.offset(0);
let mut field_cache = FxHashMap::default();
let mut field_offsets = vec![tag_offset];
field_cache.insert(
tag_offset,
(
"discriminant".to_string(),
trans_scalar(cx, span, ty, tag, tag_offset),
),
);
let def = if let TyKind::Adt(ref def, _) = ty.ty.kind() {
def
} else {
unreachable!()
};

for index in variants.indices() {
let variant_ty = ty.for_variant(cx, index);
for field in 0..variant_ty.fields.count() {
let offset = variant_ty.fields.offset(field);
match field_cache.entry(offset) {
Entry::Vacant(entry) => {
field_offsets.push(offset);
entry.insert((
def.variants[index].fields[field].ident.to_string(),
variant_ty.field(cx, field).spirv_type(span, cx),
));
}
Entry::Occupied(_) => {
// FIXME(mobius): record additional names?
}
}
}
}
field_offsets[1..].sort();

let (field_names, field_types) = field_offsets
.iter()
.map(|ofs| field_cache.remove(ofs).unwrap())
.unzip();

SpirvType::Adt {
is_enum: true,
def_id: def_id_for_spirv_type_adt(ty),
size: Some(ty.size),
align: ty.align.abi,
field_types,
field_offsets,
field_names: Some(field_names),
}
.def_with_name(cx, span, TyLayoutNameKey::from(ty))
}

// returns (field_offsets, size, align)
Expand Down Expand Up @@ -656,31 +887,25 @@ fn trans_struct<'tcx>(cx: &CodegenCx<'tcx>, span: Span, ty: TyAndLayout<'tcx>) -
let mut field_types = Vec::new();
let mut field_offsets = Vec::new();
let mut field_names = Vec::new();
let index = if let Variants::Single { index } = ty.variants {
index
} else {
unreachable!()
};
for i in ty.fields.index_by_increasing_offset() {
let field_ty = ty.field(cx, i);
field_types.push(field_ty.spirv_type(span, cx));
let offset = ty.fields.offset(i);
field_offsets.push(offset);
if let Variants::Single { index } = ty.variants {
if let TyKind::Adt(adt, _) = ty.ty.kind() {
let field = &adt.variants[index].fields[i];
field_names.push(field.ident.name.to_ident_string());
} else {
field_names.push(format!("{}", i));
}
if let TyKind::Adt(adt, _) = ty.ty.kind() {
let field = &adt.variants[index].fields[i];
field_names.push(field.ident.name.to_ident_string());
} else {
if let TyKind::Adt(_, _) = ty.ty.kind() {
} else {
span_bug!(span, "Variants::Multiple not TyKind::Adt");
}
if i == 0 {
field_names.push("discriminant".to_string());
} else {
cx.tcx.sess.fatal("Variants::Multiple has multiple fields")
}
};
field_names.push(format!("{}", i));
}
}
SpirvType::Adt {
is_enum: false,
def_id: def_id_for_spirv_type_adt(ty),
size,
align,
Expand Down
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