Compute data layout of types

This commit is contained in:
hkalbasi 2022-10-23 11:42:05 +03:30
parent 957b4bb216
commit 86b5b609f1
16 changed files with 2822 additions and 157 deletions

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@ -1,6 +1,6 @@
//! Defines hir-level representation of structs, enums and unions
use std::{num::NonZeroU32, sync::Arc};
use std::sync::Arc;
use base_db::CrateId;
use either::Either;
@ -18,6 +18,7 @@ use crate::{
db::DefDatabase,
intern::Interned,
item_tree::{AttrOwner, Field, FieldAstId, Fields, ItemTree, ModItem, RawVisibilityId},
layout::{Align, ReprFlags, ReprOptions},
nameres::diagnostics::DefDiagnostic,
src::HasChildSource,
src::HasSource,
@ -34,7 +35,7 @@ use cfg::CfgOptions;
pub struct StructData {
pub name: Name,
pub variant_data: Arc<VariantData>,
pub repr: Option<ReprData>,
pub repr: Option<ReprOptions>,
pub visibility: RawVisibility,
}
@ -42,7 +43,7 @@ pub struct StructData {
pub struct EnumData {
pub name: Name,
pub variants: Arena<EnumVariantData>,
pub repr: Option<ReprData>,
pub repr: Option<ReprOptions>,
pub visibility: RawVisibility,
}
@ -67,80 +68,74 @@ pub struct FieldData {
pub visibility: RawVisibility,
}
#[derive(Copy, Debug, Clone, PartialEq, Eq)]
pub enum ReprKind {
C,
BuiltinInt { builtin: Either<BuiltinInt, BuiltinUint>, is_c: bool },
Transparent,
Default,
}
#[derive(Copy, Debug, Clone, PartialEq, Eq)]
pub struct ReprData {
pub kind: ReprKind,
pub packed: bool,
pub align: Option<NonZeroU32>,
}
fn repr_from_value(
db: &dyn DefDatabase,
krate: CrateId,
item_tree: &ItemTree,
of: AttrOwner,
) -> Option<ReprData> {
) -> Option<ReprOptions> {
item_tree.attrs(db, krate, of).by_key("repr").tt_values().find_map(parse_repr_tt)
}
fn parse_repr_tt(tt: &Subtree) -> Option<ReprData> {
fn parse_repr_tt(tt: &Subtree) -> Option<ReprOptions> {
match tt.delimiter {
Some(Delimiter { kind: DelimiterKind::Parenthesis, .. }) => {}
_ => return None,
}
let mut data = ReprData { kind: ReprKind::Default, packed: false, align: None };
let mut flags = ReprFlags::empty();
let mut int = None;
let mut max_align: Option<Align> = None;
let mut min_pack: Option<Align> = None;
let mut tts = tt.token_trees.iter().peekable();
while let Some(tt) = tts.next() {
if let TokenTree::Leaf(Leaf::Ident(ident)) = tt {
match &*ident.text {
flags.insert(match &*ident.text {
"packed" => {
data.packed = true;
if let Some(TokenTree::Subtree(_)) = tts.peek() {
let pack = if let Some(TokenTree::Subtree(tt)) = tts.peek() {
tts.next();
}
if let Some(TokenTree::Leaf(Leaf::Literal(lit))) = tt.token_trees.first() {
lit.text.parse().unwrap_or_default()
} else {
0
}
} else {
0
};
let pack = Align::from_bytes(pack).unwrap();
min_pack =
Some(if let Some(min_pack) = min_pack { min_pack.min(pack) } else { pack });
ReprFlags::empty()
}
"align" => {
if let Some(TokenTree::Subtree(tt)) = tts.peek() {
tts.next();
if let Some(TokenTree::Leaf(Leaf::Literal(lit))) = tt.token_trees.first() {
if let Ok(align) = lit.text.parse() {
data.align = Some(align);
let align = Align::from_bytes(align).ok();
max_align = max_align.max(align);
}
}
}
ReprFlags::empty()
}
"C" => {
if let ReprKind::BuiltinInt { is_c, .. } = &mut data.kind {
*is_c = true;
} else {
data.kind = ReprKind::C;
}
}
"transparent" => data.kind = ReprKind::Transparent,
"C" => ReprFlags::IS_C,
"transparent" => ReprFlags::IS_TRANSPARENT,
repr => {
let is_c = matches!(data.kind, ReprKind::C);
if let Some(builtin) = BuiltinInt::from_suffix(repr)
.map(Either::Left)
.or_else(|| BuiltinUint::from_suffix(repr).map(Either::Right))
{
data.kind = ReprKind::BuiltinInt { builtin, is_c };
int = Some(builtin);
}
ReprFlags::empty()
}
}
})
}
}
Some(data)
Some(ReprOptions { int, align: max_align, pack: min_pack, flags })
}
impl StructData {
@ -283,7 +278,7 @@ impl EnumData {
pub fn variant_body_type(&self) -> Either<BuiltinInt, BuiltinUint> {
match self.repr {
Some(ReprData { kind: ReprKind::BuiltinInt { builtin, .. }, .. }) => builtin,
Some(ReprOptions { int: Some(builtin), .. }) => builtin,
_ => Either::Left(BuiltinInt::Isize),
}
}

1173
crates/hir-def/src/layout.rs Normal file

File diff suppressed because it is too large Load diff

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@ -34,6 +34,7 @@ pub mod adt;
pub mod data;
pub mod generics;
pub mod lang_item;
pub mod layout;
pub mod expr;
pub mod body;

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@ -419,6 +419,7 @@ pub mod known {
shr,
sub_assign,
sub,
unsafe_cell,
va_list
);

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@ -6,8 +6,11 @@ use std::sync::Arc;
use arrayvec::ArrayVec;
use base_db::{impl_intern_key, salsa, CrateId, Upcast};
use hir_def::{
db::DefDatabase, expr::ExprId, BlockId, ConstId, ConstParamId, DefWithBodyId, EnumVariantId,
FunctionId, GenericDefId, ImplId, LifetimeParamId, LocalFieldId, TypeOrConstParamId, VariantId,
db::DefDatabase,
expr::ExprId,
layout::{Layout, LayoutError, TargetDataLayout},
AdtId, BlockId, ConstId, ConstParamId, DefWithBodyId, EnumVariantId, FunctionId, GenericDefId,
ImplId, LifetimeParamId, LocalFieldId, TypeOrConstParamId, VariantId,
};
use la_arena::ArenaMap;
@ -16,7 +19,7 @@ use crate::{
consteval::{ComputedExpr, ConstEvalError},
method_resolution::{InherentImpls, TraitImpls, TyFingerprint},
Binders, CallableDefId, FnDefId, GenericArg, ImplTraitId, InferenceResult, Interner, PolyFnSig,
QuantifiedWhereClause, ReturnTypeImplTraits, TraitRef, Ty, TyDefId, ValueTyDefId,
QuantifiedWhereClause, ReturnTypeImplTraits, Substitution, TraitRef, Ty, TyDefId, ValueTyDefId,
};
use hir_expand::name::Name;
@ -57,6 +60,13 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
#[salsa::invoke(crate::lower::field_types_query)]
fn field_types(&self, var: VariantId) -> Arc<ArenaMap<LocalFieldId, Binders<Ty>>>;
#[salsa::invoke(crate::layout::layout_of_adt_query)]
#[salsa::cycle(crate::layout::layout_of_adt_recover)]
fn layout_of_adt(&self, def: AdtId, subst: Substitution) -> Result<Layout, LayoutError>;
#[salsa::invoke(crate::layout::current_target_data_layout_query)]
fn current_target_data_layout(&self) -> Arc<TargetDataLayout>;
#[salsa::invoke(crate::lower::callable_item_sig)]
fn callable_item_signature(&self, def: CallableDefId) -> PolyFnSig;

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@ -12,16 +12,16 @@ pub(crate) mod usefulness;
use chalk_ir::Mutability;
use hir_def::{
adt::VariantData, body::Body, expr::PatId, AdtId, EnumVariantId, HasModule, LocalFieldId,
VariantId,
adt::VariantData, body::Body, expr::PatId, AdtId, EnumVariantId, LocalFieldId, VariantId,
};
use hir_expand::name::{name, Name};
use hir_expand::name::Name;
use stdx::{always, never};
use crate::{
db::HirDatabase,
display::{HirDisplay, HirDisplayError, HirFormatter},
infer::BindingMode,
lang_items::is_box,
InferenceResult, Interner, Substitution, Ty, TyExt, TyKind,
};
@ -405,13 +405,6 @@ where
}
}
fn is_box(adt: AdtId, db: &dyn HirDatabase) -> bool {
let owned_box = name![owned_box].to_smol_str();
let krate = adt.module(db.upcast()).krate();
let box_adt = db.lang_item(krate, owned_box).and_then(|it| it.as_struct()).map(AdtId::from);
Some(adt) == box_adt
}
pub(crate) trait PatternFoldable: Sized {
fn fold_with<F: PatternFolder>(&self, folder: &mut F) -> Self {
self.super_fold_with(folder)

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@ -0,0 +1,20 @@
//! Functions to detect special lang items
use hir_def::{AdtId, HasModule};
use hir_expand::name;
use crate::db::HirDatabase;
pub fn is_box(adt: AdtId, db: &dyn HirDatabase) -> bool {
let owned_box = name![owned_box].to_smol_str();
let krate = adt.module(db.upcast()).krate();
let box_adt = db.lang_item(krate, owned_box).and_then(|it| it.as_struct()).map(AdtId::from);
Some(adt) == box_adt
}
pub fn is_unsafe_cell(adt: AdtId, db: &dyn HirDatabase) -> bool {
let owned_box = name![unsafe_cell].to_smol_str();
let krate = adt.module(db.upcast()).krate();
let box_adt = db.lang_item(krate, owned_box).and_then(|it| it.as_struct()).map(AdtId::from);
Some(adt) == box_adt
}

271
crates/hir-ty/src/layout.rs Normal file
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@ -0,0 +1,271 @@
//! Compute the binary representation of a type
use chalk_ir::{AdtId, TyKind};
pub(self) use hir_def::layout::*;
use hir_def::LocalFieldId;
use crate::{db::HirDatabase, Interner, Substitution, Ty};
use self::adt::univariant;
pub use self::{
adt::{layout_of_adt_query, layout_of_adt_recover},
target::current_target_data_layout_query,
};
macro_rules! user_error {
($x: expr) => {
return Err(LayoutError::UserError(format!($x)))
};
}
mod adt;
mod target;
fn scalar_unit(dl: &TargetDataLayout, value: Primitive) -> Scalar {
Scalar::Initialized { value, valid_range: WrappingRange::full(value.size(dl)) }
}
fn scalar(dl: &TargetDataLayout, value: Primitive) -> Layout {
Layout::scalar(dl, scalar_unit(dl, value))
}
fn scalar_pair(dl: &TargetDataLayout, a: Scalar, b: Scalar) -> Layout {
let b_align = b.align(dl);
let align = a.align(dl).max(b_align).max(dl.aggregate_align);
let b_offset = a.size(dl).align_to(b_align.abi);
let size = b_offset.checked_add(b.size(dl), dl).unwrap().align_to(align.abi);
// HACK(nox): We iter on `b` and then `a` because `max_by_key`
// returns the last maximum.
let largest_niche = Niche::from_scalar(dl, b_offset, b)
.into_iter()
.chain(Niche::from_scalar(dl, Size::ZERO, a))
.max_by_key(|niche| niche.available(dl));
Layout {
variants: Variants::Single,
fields: FieldsShape::Arbitrary {
offsets: vec![Size::ZERO, b_offset],
memory_index: vec![0, 1],
},
abi: Abi::ScalarPair(a, b),
largest_niche,
align,
size,
}
}
pub fn layout_of_ty(db: &dyn HirDatabase, ty: &Ty) -> Result<Layout, LayoutError> {
let dl = &*db.current_target_data_layout();
Ok(match ty.kind(Interner) {
TyKind::Adt(AdtId(def), subst) => db.layout_of_adt(*def, subst.clone())?,
TyKind::Scalar(s) => match s {
chalk_ir::Scalar::Bool => Layout::scalar(
dl,
Scalar::Initialized {
value: Primitive::Int(Integer::I8, false),
valid_range: WrappingRange { start: 0, end: 1 },
},
),
chalk_ir::Scalar::Char => Layout::scalar(
dl,
Scalar::Initialized {
value: Primitive::Int(Integer::I32, false),
valid_range: WrappingRange { start: 0, end: 0x10FFFF },
},
),
chalk_ir::Scalar::Int(i) => scalar(
dl,
Primitive::Int(
match i {
chalk_ir::IntTy::Isize => dl.ptr_sized_integer(),
chalk_ir::IntTy::I8 => Integer::I8,
chalk_ir::IntTy::I16 => Integer::I16,
chalk_ir::IntTy::I32 => Integer::I32,
chalk_ir::IntTy::I64 => Integer::I64,
chalk_ir::IntTy::I128 => Integer::I128,
},
false,
),
),
chalk_ir::Scalar::Uint(i) => scalar(
dl,
Primitive::Int(
match i {
chalk_ir::UintTy::Usize => dl.ptr_sized_integer(),
chalk_ir::UintTy::U8 => Integer::I8,
chalk_ir::UintTy::U16 => Integer::I16,
chalk_ir::UintTy::U32 => Integer::I32,
chalk_ir::UintTy::U64 => Integer::I64,
chalk_ir::UintTy::U128 => Integer::I128,
},
true,
),
),
chalk_ir::Scalar::Float(f) => scalar(
dl,
match f {
chalk_ir::FloatTy::F32 => Primitive::F32,
chalk_ir::FloatTy::F64 => Primitive::F64,
},
),
},
TyKind::Tuple(len, tys) => {
let kind = if *len == 0 { StructKind::AlwaysSized } else { StructKind::MaybeUnsized };
univariant(
dl,
&tys.iter(Interner)
.map(|k| layout_of_ty(db, k.assert_ty_ref(Interner)))
.collect::<Result<Vec<_>, _>>()?,
&ReprOptions::default(),
kind,
)?
}
TyKind::Array(element, count) => {
let count = match count.data(Interner).value {
chalk_ir::ConstValue::Concrete(c) => match c.interned {
hir_def::type_ref::ConstScalar::Int(x) => x as u64,
hir_def::type_ref::ConstScalar::UInt(x) => x as u64,
hir_def::type_ref::ConstScalar::Unknown => {
user_error!("unknown const generic parameter")
}
_ => user_error!("mismatched type of const generic parameter"),
},
_ => return Err(LayoutError::HasPlaceholder),
};
let element = layout_of_ty(db, element)?;
let size = element.size.checked_mul(count, dl).ok_or(LayoutError::SizeOverflow)?;
let abi = if count != 0 && matches!(element.abi, Abi::Uninhabited) {
Abi::Uninhabited
} else {
Abi::Aggregate { sized: true }
};
let largest_niche = if count != 0 { element.largest_niche } else { None };
Layout {
variants: Variants::Single,
fields: FieldsShape::Array { stride: element.size, count },
abi,
largest_niche,
align: element.align,
size,
}
}
TyKind::Slice(element) => {
let element = layout_of_ty(db, element)?;
Layout {
variants: Variants::Single,
fields: FieldsShape::Array { stride: element.size, count: 0 },
abi: Abi::Aggregate { sized: false },
largest_niche: None,
align: element.align,
size: Size::ZERO,
}
}
// Potentially-wide pointers.
TyKind::Ref(_, _, pointee) | TyKind::Raw(_, pointee) => {
let mut data_ptr = scalar_unit(dl, Primitive::Pointer);
if matches!(ty.kind(Interner), TyKind::Ref(..)) {
data_ptr.valid_range_mut().start = 1;
}
// let pointee = tcx.normalize_erasing_regions(param_env, pointee);
// if pointee.is_sized(tcx.at(DUMMY_SP), param_env) {
// return Ok(tcx.intern_layout(LayoutS::scalar(cx, data_ptr)));
// }
let unsized_part = struct_tail_erasing_lifetimes(db, pointee.clone());
let metadata = match unsized_part.kind(Interner) {
TyKind::Slice(_) | TyKind::Str => {
scalar_unit(dl, Primitive::Int(dl.ptr_sized_integer(), false))
}
TyKind::Dyn(..) => {
let mut vtable = scalar_unit(dl, Primitive::Pointer);
vtable.valid_range_mut().start = 1;
vtable
}
_ => {
// pointee is sized
return Ok(Layout::scalar(dl, data_ptr));
}
};
// Effectively a (ptr, meta) tuple.
scalar_pair(dl, data_ptr, metadata)
}
TyKind::FnDef(_, _) => {
univariant(dl, &[], &ReprOptions::default(), StructKind::AlwaysSized)?
}
TyKind::Str => Layout {
variants: Variants::Single,
fields: FieldsShape::Array { stride: Size::from_bytes(1), count: 0 },
abi: Abi::Aggregate { sized: false },
largest_niche: None,
align: dl.i8_align,
size: Size::ZERO,
},
TyKind::Never => Layout {
variants: Variants::Single,
fields: FieldsShape::Primitive,
abi: Abi::Uninhabited,
largest_niche: None,
align: dl.i8_align,
size: Size::ZERO,
},
TyKind::Dyn(_) | TyKind::Foreign(_) => {
let mut unit = univariant(dl, &[], &ReprOptions::default(), StructKind::AlwaysSized)?;
match unit.abi {
Abi::Aggregate { ref mut sized } => *sized = false,
_ => user_error!("bug"),
}
unit
}
TyKind::Function(_) => {
let mut ptr = scalar_unit(dl, Primitive::Pointer);
ptr.valid_range_mut().start = 1;
Layout::scalar(dl, ptr)
}
TyKind::Closure(_, _)
| TyKind::OpaqueType(_, _)
| TyKind::Generator(_, _)
| TyKind::GeneratorWitness(_, _) => return Err(LayoutError::NotImplemented),
TyKind::AssociatedType(_, _)
| TyKind::Error
| TyKind::Alias(_)
| TyKind::Placeholder(_)
| TyKind::BoundVar(_)
| TyKind::InferenceVar(_, _) => return Err(LayoutError::HasPlaceholder),
})
}
fn struct_tail_erasing_lifetimes(db: &dyn HirDatabase, pointee: Ty) -> Ty {
match pointee.kind(Interner) {
TyKind::Adt(AdtId(adt), subst) => match adt {
&hir_def::AdtId::StructId(i) => {
let data = db.struct_data(i);
let mut it = data.variant_data.fields().iter().rev();
match it.next() {
Some((f, _)) => field_ty(db, i.into(), f, subst),
None => pointee,
}
}
_ => pointee,
},
_ => pointee,
}
}
fn field_ty(
db: &dyn HirDatabase,
def: hir_def::VariantId,
fd: LocalFieldId,
subst: &Substitution,
) -> Ty {
db.field_types(def)[fd].clone().substitute(Interner, subst)
}
#[cfg(test)]
mod tests;

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@ -0,0 +1,900 @@
//! Compute the binary representation of structs, unions and enums
use std::{
cmp::{self, Ordering},
iter,
num::NonZeroUsize,
};
use chalk_ir::TyKind;
use hir_def::{
adt::VariantData,
layout::{
Abi, AbiAndPrefAlign, Align, FieldsShape, Integer, Layout, LayoutError, Niche, Primitive,
ReprOptions, Scalar, Size, StructKind, TagEncoding, TargetDataLayout, Variants,
WrappingRange,
},
AdtId, EnumVariantId, LocalEnumVariantId, UnionId, VariantId,
};
use la_arena::{ArenaMap, RawIdx};
use crate::{
db::HirDatabase,
lang_items::is_unsafe_cell,
layout::{field_ty, scalar_unit},
Interner, Substitution,
};
use super::layout_of_ty;
pub fn layout_of_adt_query(
db: &dyn HirDatabase,
def: AdtId,
subst: Substitution,
) -> Result<Layout, LayoutError> {
let handle_variant = |def: VariantId, var: &VariantData| {
var.fields()
.iter()
.map(|(fd, _)| layout_of_ty(db, &field_ty(db, def, fd, &subst)))
.collect::<Result<Vec<_>, _>>()
};
fn struct_variant_idx() -> LocalEnumVariantId {
LocalEnumVariantId::from_raw(RawIdx::from(0))
}
let (variants, is_enum, repr) = match def {
AdtId::StructId(s) => {
let data = db.struct_data(s);
let mut r = ArenaMap::new();
r.insert(struct_variant_idx(), handle_variant(s.into(), &data.variant_data)?);
(r, false, data.repr.unwrap_or_default())
}
AdtId::UnionId(id) => return layout_of_union(db, id, &subst),
AdtId::EnumId(e) => {
let data = db.enum_data(e);
let r = data
.variants
.iter()
.map(|(idx, v)| {
Ok((
idx,
handle_variant(
EnumVariantId { parent: e, local_id: idx }.into(),
&v.variant_data,
)?,
))
})
.collect::<Result<_, _>>()?;
(r, true, data.repr.unwrap_or_default())
}
};
// A variant is absent if it's uninhabited and only has ZST fields.
// Present uninhabited variants only require space for their fields,
// 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: &[Layout]| {
let uninhabited = fields.iter().any(|f| f.abi.is_uninhabited());
let is_zst = fields.iter().all(|f| f.is_zst());
uninhabited && is_zst
};
let (present_first, present_second) = {
let mut present_variants =
variants.iter().filter_map(|(i, v)| if absent(v) { None } else { Some(i) });
(present_variants.next(), present_variants.next())
};
let present_first = match present_first {
Some(present_first) => present_first,
// Uninhabited because it has no variants, or only absent ones.
None if is_enum => return layout_of_ty(db, &TyKind::Never.intern(Interner)),
// If it's a struct, still compute a layout so that we can still compute the
// field offsets.
None => struct_variant_idx(),
};
let is_univariant = !is_enum ||
// Only one variant is present.
(present_second.is_none() &&
// Representation optimizations are allowed.
!repr.inhibit_enum_layout_opt());
let dl = &*db.current_target_data_layout();
if is_univariant {
// Struct, or univariant enum equivalent to a struct.
// (Typechecking will reject discriminant-sizing attrs.)
let v = present_first;
let kind = if is_enum || variants[v].is_empty() {
StructKind::AlwaysSized
} else {
let always_sized = !variants[v].last().unwrap().is_unsized();
if !always_sized {
StructKind::MaybeUnsized
} else {
StructKind::AlwaysSized
}
};
let mut st = univariant(dl, &variants[v], &repr, kind)?;
st.variants = Variants::Single;
if is_unsafe_cell(def, db) {
let hide_niches = |scalar: &mut _| match scalar {
Scalar::Initialized { value, valid_range } => {
*valid_range = WrappingRange::full(value.size(dl))
}
// Already doesn't have any niches
Scalar::Union { .. } => {}
};
match &mut st.abi {
Abi::Uninhabited => {}
Abi::Scalar(scalar) => hide_niches(scalar),
Abi::ScalarPair(a, b) => {
hide_niches(a);
hide_niches(b);
}
Abi::Vector { element, count: _ } => hide_niches(element),
Abi::Aggregate { sized: _ } => {}
}
st.largest_niche = None;
}
return Ok(st);
}
// Until we've decided whether to use the tagged or
// niche filling LayoutS, we don't want to intern the
// 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: Layout,
variants: ArenaMap<LocalEnumVariantId, Layout>,
}
let calculate_niche_filling_layout = || -> Result<Option<TmpLayout>, LayoutError> {
// The current code for niche-filling relies on variant indices
// instead of actual discriminants, so enums with
// explicit discriminants (RFC #2363) would misbehave.
if repr.inhibit_enum_layout_opt()
// FIXME: bring these codes back
// || def
// .variants()
// .iter_enumerated()
// .any(|(i, v)| v.discr != ty::VariantDiscr::Relative(i.as_u32()))
{
return Ok(None);
}
if variants.iter().count() < 2 {
return Ok(None);
}
let mut align = dl.aggregate_align;
let mut variant_layouts = variants
.iter()
.map(|(j, v)| {
let mut st = univariant(dl, v, &repr, StructKind::AlwaysSized)?;
st.variants = Variants::Single;
align = align.max(st.align);
Ok((j, st))
})
.collect::<Result<ArenaMap<_, _>, _>>()?;
let largest_variant_index = match variant_layouts
.iter()
.max_by_key(|(_i, layout)| layout.size.bytes())
.map(|(i, _layout)| i)
{
None => return Ok(None),
Some(i) => i,
};
let count = variants
.iter()
.map(|(i, _)| i)
.filter(|x| *x != largest_variant_index && !absent(&variants[*x]))
.count() as u128;
// Find the field with the largest niche
let (field_index, niche, (niche_start, niche_scalar)) = match variants
[largest_variant_index]
.iter()
.enumerate()
.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)?)))
{
None => return Ok(None),
Some(x) => x,
};
let niche_offset =
niche.offset + variant_layouts[largest_variant_index].fields.offset(field_index, dl);
let niche_size = niche.value.size(dl);
let size = variant_layouts[largest_variant_index].size.align_to(align.abi);
let all_variants_fit = variant_layouts.iter_mut().all(|(i, layout)| {
if i == largest_variant_index {
return true;
}
layout.largest_niche = None;
if layout.size <= niche_offset {
// This variant will fit before the niche.
return true;
}
// Determine if it'll fit after the niche.
let this_align = layout.align.abi;
let this_offset = (niche_offset + niche_size).align_to(this_align);
if this_offset + layout.size > size {
return false;
}
// It'll fit, but we need to make some adjustments.
match layout.fields {
FieldsShape::Arbitrary { ref mut offsets, .. } => {
for (j, offset) in offsets.iter_mut().enumerate() {
if !variants[i][j].is_zst() {
*offset += this_offset;
}
}
}
_ => {
panic!("Layout of fields should be Arbitrary for variants")
}
}
// It can't be a Scalar or ScalarPair because the offset isn't 0.
if !layout.abi.is_uninhabited() {
layout.abi = Abi::Aggregate { sized: true };
}
layout.size += this_offset;
true
});
if !all_variants_fit {
return Ok(None);
}
let largest_niche = Niche::from_scalar(dl, niche_offset, niche_scalar);
let others_zst = variant_layouts
.iter()
.all(|(i, layout)| i == largest_variant_index || layout.size == Size::ZERO);
let same_size = size == variant_layouts[largest_variant_index].size;
let same_align = align == variant_layouts[largest_variant_index].align;
let abi = if variant_layouts.iter().all(|(_, v)| v.abi.is_uninhabited()) {
Abi::Uninhabited
} else if same_size && same_align && others_zst {
match variant_layouts[largest_variant_index].abi {
// When the total alignment and size match, we can use the
// same ABI as the scalar variant with the reserved niche.
Abi::Scalar(_) => Abi::Scalar(niche_scalar),
Abi::ScalarPair(first, second) => {
// Only the niche is guaranteed to be initialised,
// so use union layouts for the other primitive.
if niche_offset == Size::ZERO {
Abi::ScalarPair(niche_scalar, second.to_union())
} else {
Abi::ScalarPair(first.to_union(), niche_scalar)
}
}
_ => Abi::Aggregate { sized: true },
}
} else {
Abi::Aggregate { sized: true }
};
let layout = Layout {
variants: Variants::Multiple {
tag: niche_scalar,
tag_encoding: TagEncoding::Niche {
untagged_variant: largest_variant_index,
niche_start,
},
tag_field: 0,
variants: ArenaMap::new(),
},
fields: FieldsShape::Arbitrary { offsets: vec![niche_offset], memory_index: vec![0] },
abi,
largest_niche,
size,
align,
};
Ok(Some(TmpLayout { layout, variants: variant_layouts }))
};
let niche_filling_layout = calculate_niche_filling_layout()?;
let (mut min, mut max) = (i128::MAX, i128::MIN);
// FIXME: bring these back
// let discr_type = repr.discr_type();
// let bits = Integer::from_attr(dl, discr_type).size().bits();
// for (i, discr) in def.discriminants(tcx) {
// if variants[i].iter().any(|f| f.abi.is_uninhabited()) {
// continue;
// }
// let mut x = discr.val as i128;
// if discr_type.is_signed() {
// // sign extend the raw representation to be an i128
// x = (x << (128 - bits)) >> (128 - bits);
// }
// if x < min {
// min = x;
// }
// if x > max {
// max = x;
// }
// }
// We might have no inhabited variants, so pretend there's at least one.
if (min, max) == (i128::MAX, i128::MIN) {
min = 0;
max = 0;
}
assert!(min <= max, "discriminant range is {}...{}", min, max);
let (min_ity, signed) = Integer::repr_discr(dl, &repr, min, max)?;
let mut align = dl.aggregate_align;
let mut size = Size::ZERO;
// We're interested in the smallest alignment, so start large.
let mut start_align = Align::from_bytes(256).unwrap();
assert_eq!(Integer::for_align(dl, start_align), None);
// repr(C) on an enum tells us to make a (tag, union) layout,
// so we need to grow the prefix alignment to be at least
// the alignment of the union. (This value is used both for
// determining the alignment of the overall enum, and the
// determining the alignment of the payload after the tag.)
let mut prefix_align = min_ity.align(dl).abi;
if repr.c() {
for (_, fields) in variants.iter() {
for field in fields {
prefix_align = prefix_align.max(field.align.abi);
}
}
}
// Create the set of structs that represent each variant.
let mut layout_variants = variants
.iter()
.map(|(i, field_layouts)| {
let mut st = univariant(
dl,
&field_layouts,
&repr,
StructKind::Prefixed(min_ity.size(), prefix_align),
)?;
st.variants = Variants::Single;
// 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);
break;
}
}
size = cmp::max(size, st.size);
align = align.max(st.align);
Ok((i, st))
})
.collect::<Result<ArenaMap<_, _>, _>>()?;
// Align the maximum variant size to the largest alignment.
size = size.align_to(align.abi);
if size.bytes() >= dl.obj_size_bound() {
return Err(LayoutError::SizeOverflow);
}
// Check to see if we should use a different type for the
// discriminant. We can safely use a type with the same size
// as the alignment of the first field of each variant.
// We increase the size of the discriminant to avoid LLVM copying
// padding when it doesn't need to. This normally causes unaligned
// load/stores and excessive memcpy/memset operations. By using a
// bigger integer size, LLVM can be sure about its contents and
// won't be so conservative.
// Use the initial field alignment
let mut ity = if repr.c() || repr.int.is_some() {
min_ity
} else {
Integer::for_align(dl, start_align).unwrap_or(min_ity)
};
// If the alignment is not larger than the chosen discriminant size,
// don't use the alignment as the final size.
if ity <= min_ity {
ity = min_ity;
} else {
// Patch up the variants' first few fields.
// Patch up the variants' first few fields.
let old_ity_size = min_ity.size();
let new_ity_size = ity.size();
for (_, variant) in layout_variants.iter_mut() {
match variant.fields {
FieldsShape::Arbitrary { ref mut offsets, .. } => {
for i in offsets {
if *i <= old_ity_size {
assert_eq!(*i, old_ity_size);
*i = new_ity_size;
}
}
// We might be making the struct larger.
if variant.size <= old_ity_size {
variant.size = new_ity_size;
}
}
_ => user_error!("bug"),
}
}
}
let tag_mask = ity.size().unsigned_int_max();
let tag = Scalar::Initialized {
value: Primitive::Int(ity, signed),
valid_range: WrappingRange {
start: (min as u128 & tag_mask),
end: (max as u128 & tag_mask),
},
};
let mut abi = Abi::Aggregate { sized: true };
if layout_variants.iter().all(|(_, v)| v.abi.is_uninhabited()) {
abi = Abi::Uninhabited;
} else if tag.size(dl) == size {
// Make sure we only use scalar layout when the enum is entirely its
// own tag (i.e. it has no padding nor any non-ZST variant fields).
abi = Abi::Scalar(tag);
} else {
// Try to use a ScalarPair for all tagged enums.
let mut common_prim = None;
let mut common_prim_initialized_in_all_variants = true;
for ((_, field_layouts), (_, layout_variant)) in
iter::zip(variants.iter(), layout_variants.iter())
{
let offsets = match layout_variant.fields {
FieldsShape::Arbitrary { ref offsets, .. } => offsets,
_ => user_error!("bug"),
};
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;
continue;
}
(Some(pair), None) => pair,
_ => {
common_prim = None;
break;
}
};
let prim = match field.abi {
Abi::Scalar(scalar) => {
common_prim_initialized_in_all_variants &=
matches!(scalar, Scalar::Initialized { .. });
scalar.primitive()
}
_ => {
common_prim = None;
break;
}
};
if let Some(pair) = common_prim {
// This is pretty conservative. We could go fancier
// by conflating things like i32 and u32, or even
// realising that (u8, u8) could just cohabit with
// u16 or even u32.
if pair != (prim, offset) {
common_prim = None;
break;
}
} else {
common_prim = Some((prim, offset));
}
}
if let Some((prim, offset)) = common_prim {
let prim_scalar = if common_prim_initialized_in_all_variants {
scalar_unit(dl, prim)
} else {
// Common prim might be uninit.
Scalar::Union { value: prim }
};
let pair = scalar_pair(dl, tag, prim_scalar);
let pair_offsets = match pair.fields {
FieldsShape::Arbitrary { ref offsets, ref memory_index } => {
assert_eq!(memory_index, &[0, 1]);
offsets
}
_ => user_error!("bug"),
};
if pair_offsets[0] == Size::ZERO
&& pair_offsets[1] == *offset
&& align == pair.align
&& size == pair.size
{
// We can use `ScalarPair` only when it matches our
// already computed layout (including `#[repr(C)]`).
abi = pair.abi;
}
}
}
// If we pick a "clever" (by-value) ABI, we might have to adjust the ABI of the
// variants to ensure they are consistent. This is because a downcast is
// semantically a NOP, and thus should not affect layout.
if matches!(abi, Abi::Scalar(..) | Abi::ScalarPair(..)) {
for (_, variant) in layout_variants.iter_mut() {
// We only do this for variants with fields; the others are not accessed anyway.
// Also do not overwrite any already existing "clever" ABIs.
if variant.fields.count() > 0 && matches!(variant.abi, Abi::Aggregate { .. }) {
variant.abi = abi;
// Also need to bump up the size and alignment, so that the entire value fits in here.
variant.size = cmp::max(variant.size, size);
variant.align.abi = cmp::max(variant.align.abi, align.abi);
}
}
}
let largest_niche = Niche::from_scalar(dl, Size::ZERO, tag);
let tagged_layout = Layout {
variants: Variants::Multiple {
tag,
tag_encoding: TagEncoding::Direct,
tag_field: 0,
variants: ArenaMap::new(),
},
fields: FieldsShape::Arbitrary { offsets: vec![Size::ZERO], memory_index: vec![0] },
largest_niche,
abi,
align,
size,
};
let tagged_layout = TmpLayout { layout: tagged_layout, variants: layout_variants };
let mut best_layout = match (tagged_layout, niche_filling_layout) {
(tl, Some(nl)) => {
// Pick the smaller layout; otherwise,
// pick the layout with the larger niche; otherwise,
// pick tagged as it has simpler codegen.
use Ordering::*;
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,
_ => tl,
}
}
(tl, None) => tl,
};
// Now we can intern the variant layouts and store them in the enum layout.
best_layout.layout.variants = match best_layout.layout.variants {
Variants::Multiple { tag, tag_encoding, tag_field, .. } => {
Variants::Multiple { tag, tag_encoding, tag_field, variants: best_layout.variants }
}
_ => user_error!("bug"),
};
Ok(best_layout.layout)
}
pub fn layout_of_adt_recover(
_: &dyn HirDatabase,
_: &[String],
_: &AdtId,
_: &Substitution,
) -> Result<Layout, LayoutError> {
user_error!("infinite sized recursive type");
}
pub(crate) fn univariant(
dl: &TargetDataLayout,
fields: &[Layout],
repr: &ReprOptions,
kind: StructKind,
) -> Result<Layout, LayoutError> {
let pack = repr.pack;
if pack.is_some() && repr.align.is_some() {
user_error!("Struct can not be packed and aligned");
}
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();
let optimize = !repr.inhibit_struct_field_reordering_opt();
if optimize {
let end = if let StructKind::MaybeUnsized = kind { fields.len() - 1 } else { fields.len() };
let optimizing = &mut inverse_memory_index[..end];
let field_align = |f: &Layout| {
if let Some(pack) = pack {
f.align.abi.min(pack)
} else {
f.align.abi
}
};
match kind {
StructKind::AlwaysSized | StructKind::MaybeUnsized => {
optimizing.sort_by_key(|&x| {
// Place ZSTs first to avoid "interesting offsets",
// especially with only one or two non-ZST fields.
let f = &fields[x as usize];
(!f.is_zst(), cmp::Reverse(field_align(f)))
});
}
StructKind::Prefixed(..) => {
// Sort in ascending alignment so that the layout stays optimal
// regardless of the prefix
optimizing.sort_by_key(|&x| field_align(&fields[x as usize]));
}
}
}
// inverse_memory_index holds field indices by increasing memory offset.
// That is, if field 5 has offset 0, the first element of inverse_memory_index is 5.
// We now write field offsets to the corresponding offset slot;
// field 5 with offset 0 puts 0 in offsets[5].
// At the bottom of this function, we invert `inverse_memory_index` to
// produce `memory_index` (see `invert_mapping`).
let mut sized = true;
let mut offsets = vec![Size::ZERO; fields.len()];
let mut offset = Size::ZERO;
let mut largest_niche = None;
let mut largest_niche_available = 0;
if let StructKind::Prefixed(prefix_size, prefix_align) = kind {
let prefix_align =
if let Some(pack) = pack { prefix_align.min(pack) } else { prefix_align };
align = align.max(AbiAndPrefAlign::new(prefix_align));
offset = prefix_size.align_to(prefix_align);
}
for &i in &inverse_memory_index {
let field = &fields[i as usize];
if !sized {
user_error!("Unsized field is not last field");
}
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))
} else {
field.align
};
offset = offset.align_to(field_align.abi);
align = align.max(field_align);
offsets[i as usize] = offset;
if let Some(mut niche) = field.largest_niche {
let available = niche.available(dl);
if available > largest_niche_available {
largest_niche_available = available;
niche.offset =
niche.offset.checked_add(offset, dl).ok_or(LayoutError::SizeOverflow)?;
largest_niche = Some(niche);
}
}
offset = offset.checked_add(field.size, dl).ok_or(LayoutError::SizeOverflow)?;
}
if let Some(repr_align) = repr.align {
align = align.max(AbiAndPrefAlign::new(repr_align));
}
let min_size = offset;
// As stated above, inverse_memory_index holds field indices by increasing offset.
// This makes it an already-sorted view of the offsets vec.
// To invert it, consider:
// If field 5 has offset 0, offsets[0] is 5, and memory_index[5] should be 0.
// Field 5 would be the first element, so memory_index is i:
// Note: if we didn't optimize, it's already right.
let memory_index =
if optimize { invert_mapping(&inverse_memory_index) } else { inverse_memory_index };
let size = min_size.align_to(align.abi);
let mut abi = Abi::Aggregate { sized };
// 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());
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 {
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;
}
// But scalar pairs are Rust-specific and get
// treated as aggregates by C ABIs anyway.
Abi::ScalarPair(..) => {
abi = field.abi;
}
_ => {}
}
}
}
// Two non-ZST fields, and they're both scalars.
(Some((i, a)), Some((j, b)), None) => {
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] {
((i, a), (j, b))
} else {
((j, b), (i, a))
};
let pair = scalar_pair(dl, a, b);
let pair_offsets = match pair.fields {
FieldsShape::Arbitrary { ref offsets, .. } => offsets,
_ => unreachable!(),
};
if offsets[i] == pair_offsets[0]
&& offsets[j] == pair_offsets[1]
&& align == pair.align
&& size == pair.size
{
// We can use `ScalarPair` only when it matches our
// already computed layout (including `#[repr(C)]`).
abi = pair.abi;
}
}
_ => {}
}
}
_ => {}
}
}
if fields.iter().any(|f| f.abi.is_uninhabited()) {
abi = Abi::Uninhabited;
}
Ok(Layout {
variants: Variants::Single,
fields: FieldsShape::Arbitrary { offsets, memory_index },
abi,
largest_niche,
align,
size,
})
}
fn layout_of_union(
db: &dyn HirDatabase,
id: UnionId,
subst: &Substitution,
) -> Result<Layout, LayoutError> {
let dl = &*db.current_target_data_layout();
let union_data = db.union_data(id);
let repr = union_data.repr.unwrap_or_default();
let fields = union_data.variant_data.fields();
if repr.pack.is_some() && repr.align.is_some() {
user_error!("union cannot be packed and aligned");
}
let mut align = if repr.pack.is_some() { dl.i8_align } else { dl.aggregate_align };
if let Some(repr_align) = repr.align {
align = align.max(AbiAndPrefAlign::new(repr_align));
}
let optimize = !repr.inhibit_union_abi_opt();
let mut size = Size::ZERO;
let mut abi = Abi::Aggregate { sized: true };
for (fd, _) in fields.iter() {
let field_ty = field_ty(db, id.into(), fd, subst);
let field = layout_of_ty(db, &field_ty)?;
if field.is_unsized() {
user_error!("unsized union field");
}
// If all non-ZST fields have the same ABI, forward this ABI
if optimize && !field.is_zst() {
// Discard valid range information and allow undef
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 } => Abi::Vector { element: x.to_union(), count },
Abi::Uninhabited | Abi::Aggregate { .. } => Abi::Aggregate { sized: true },
};
if size == Size::ZERO {
// first non ZST: initialize 'abi'
abi = field_abi;
} else if abi != field_abi {
// different fields have different ABI: reset to Aggregate
abi = Abi::Aggregate { sized: true };
}
}
size = cmp::max(size, field.size);
}
if let Some(pack) = repr.pack {
align = align.min(AbiAndPrefAlign::new(pack));
}
Ok(Layout {
variants: Variants::Single,
fields: FieldsShape::Union(
NonZeroUsize::new(fields.len())
.ok_or(LayoutError::UserError("union with zero fields".to_string()))?,
),
abi,
largest_niche: None,
align,
size: size.align_to(align.abi),
})
}
// Invert a bijective mapping, i.e. `invert(map)[y] = x` if `map[x] = y`.
// This is used to go between `memory_index` (source field order to memory order)
// and `inverse_memory_index` (memory order to source field order).
// See also `FieldsShape::Arbitrary::memory_index` for more details.
// FIXME(eddyb) build a better abstraction for permutations, if possible.
fn invert_mapping(map: &[u32]) -> Vec<u32> {
let mut inverse = vec![0; map.len()];
for i in 0..map.len() {
inverse[map[i] as usize] = i as u32;
}
inverse
}
fn scalar_pair(dl: &TargetDataLayout, a: Scalar, b: Scalar) -> Layout {
let b_align = b.align(dl);
let align = a.align(dl).max(b_align).max(dl.aggregate_align);
let b_offset = a.size(dl).align_to(b_align.abi);
let size = b_offset.checked_add(b.size(dl), dl).unwrap().align_to(align.abi);
// HACK(nox): We iter on `b` and then `a` because `max_by_key`
// returns the last maximum.
let largest_niche = Niche::from_scalar(dl, b_offset, b)
.into_iter()
.chain(Niche::from_scalar(dl, Size::ZERO, a))
.max_by_key(|niche| niche.available(dl));
Layout {
variants: Variants::Single,
fields: FieldsShape::Arbitrary {
offsets: vec![Size::ZERO, b_offset],
memory_index: vec![0, 1],
},
abi: Abi::ScalarPair(a, b),
largest_niche,
align,
size,
}
}

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@ -0,0 +1,44 @@
//! Target dependent parameters needed for layouts
use std::sync::Arc;
use hir_def::layout::TargetDataLayout;
use crate::db::HirDatabase;
use super::{AbiAndPrefAlign, AddressSpace, Align, Endian, Integer, Size};
pub fn current_target_data_layout_query(db: &dyn HirDatabase) -> Arc<TargetDataLayout> {
let crate_graph = db.crate_graph();
let cfg_options = &crate_graph[crate_graph.iter().next().unwrap()].cfg_options;
let endian = match cfg_options.get_cfg_values("target_endian").next() {
Some(x) if x.as_str() == "big" => Endian::Big,
_ => Endian::Little,
};
let pointer_size =
Size::from_bytes(match cfg_options.get_cfg_values("target_pointer_width").next() {
Some(x) => match x.as_str() {
"16" => 2,
"32" => 4,
_ => 8,
},
_ => 8,
});
Arc::new(TargetDataLayout {
endian,
i1_align: AbiAndPrefAlign::new(Align::from_bytes(1).unwrap()),
i8_align: AbiAndPrefAlign::new(Align::from_bytes(1).unwrap()),
i16_align: AbiAndPrefAlign::new(Align::from_bytes(2).unwrap()),
i32_align: AbiAndPrefAlign::new(Align::from_bytes(4).unwrap()),
i64_align: AbiAndPrefAlign::new(Align::from_bytes(8).unwrap()),
i128_align: AbiAndPrefAlign::new(Align::from_bytes(8).unwrap()),
f32_align: AbiAndPrefAlign::new(Align::from_bytes(4).unwrap()),
f64_align: AbiAndPrefAlign::new(Align::from_bytes(8).unwrap()),
pointer_size,
pointer_align: AbiAndPrefAlign::new(Align::from_bytes(8).unwrap()),
aggregate_align: AbiAndPrefAlign::new(Align::from_bytes(1).unwrap()),
vector_align: vec![],
instruction_address_space: AddressSpace(0),
c_enum_min_size: Integer::I32,
})
}

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@ -0,0 +1,167 @@
use base_db::fixture::WithFixture;
use chalk_ir::{AdtId, TyKind};
use hir_def::{
db::DefDatabase,
layout::{Layout, LayoutError},
};
use crate::{test_db::TestDB, Interner, Substitution};
use super::layout_of_ty;
fn eval_goal(ra_fixture: &str) -> Result<Layout, LayoutError> {
let (db, file_id) = TestDB::with_single_file(ra_fixture);
let module_id = db.module_for_file(file_id);
let def_map = module_id.def_map(&db);
let scope = &def_map[module_id.local_id].scope;
let adt_id = scope
.declarations()
.into_iter()
.find_map(|x| match x {
hir_def::ModuleDefId::AdtId(x) => {
let name = match x {
hir_def::AdtId::StructId(x) => db.struct_data(x).name.to_string(),
hir_def::AdtId::UnionId(x) => db.union_data(x).name.to_string(),
hir_def::AdtId::EnumId(x) => db.enum_data(x).name.to_string(),
};
if name == "Goal" {
Some(x)
} else {
None
}
}
_ => None,
})
.unwrap();
let goal_ty = TyKind::Adt(AdtId(adt_id), Substitution::empty(Interner)).intern(Interner);
layout_of_ty(&db, &goal_ty)
}
fn check_size_and_align(ra_fixture: &str, size: u64, align: u64) {
let l = eval_goal(ra_fixture).unwrap();
assert_eq!(l.size.bytes(), size);
assert_eq!(l.align.abi.bytes(), align);
}
fn check_fail(ra_fixture: &str, e: LayoutError) {
let r = eval_goal(ra_fixture);
assert_eq!(r, Err(e));
}
macro_rules! size_and_align {
($($t:tt)*) => {
{
#[allow(dead_code)]
$($t)*
check_size_and_align(
stringify!($($t)*),
::std::mem::size_of::<Goal>() as u64,
::std::mem::align_of::<Goal>() as u64,
);
}
};
}
#[test]
fn hello_world() {
size_and_align! {
struct Goal(i32);
}
//check_size_and_align(r#"struct Goal(i32)"#, 4, 4);
}
#[test]
fn field_order_optimization() {
size_and_align! {
struct Goal(u8, i32, u8);
}
size_and_align! {
#[repr(C)]
struct Goal(u8, i32, u8);
}
}
#[test]
fn recursive() {
size_and_align! {
struct Goal {
left: &'static Goal,
right: &'static Goal,
}
}
size_and_align! {
struct BoxLike<T: ?Sized>(*mut T);
struct Goal(BoxLike<Goal>);
}
check_fail(
r#"struct Goal(Goal);"#,
LayoutError::UserError("infinite sized recursive type".to_string()),
);
check_fail(
r#"
struct Foo<T>(Foo<T>);
struct Goal(Foo<i32>);
"#,
LayoutError::UserError("infinite sized recursive type".to_string()),
);
}
#[test]
fn generic() {
size_and_align! {
struct Pair<A, B>(A, B);
struct Goal(Pair<Pair<i32, u8>, i64>);
}
size_and_align! {
struct X<const N: usize> {
field1: [i32; N],
field2: [u8; N],
}
struct Goal(X<1000>);
}
}
#[test]
fn enums() {
size_and_align! {
enum Goal {
Quit,
Move { x: i32, y: i32 },
ChangeColor(i32, i32, i32),
}
}
}
#[test]
fn primitives() {
size_and_align! {
struct Goal(i32, i128, isize, usize, f32, f64, bool, char);
}
}
#[test]
fn tuple() {
size_and_align! {
struct Goal((), (i32, u64, bool));
}
}
#[test]
fn niche_optimization() {
check_size_and_align(
r#"
//- minicore: option
struct Goal(Option<&i32>);
"#,
8,
8,
);
check_size_and_align(
r#"
//- minicore: option
struct Goal(Option<Option<bool>>);
"#,
1,
1,
);
}

View file

@ -27,6 +27,8 @@ pub mod display;
pub mod method_resolution;
pub mod primitive;
pub mod traits;
pub mod layout;
pub mod lang_items;
#[cfg(test)]
mod tests;

View file

@ -39,12 +39,13 @@ use arrayvec::ArrayVec;
use base_db::{CrateDisplayName, CrateId, CrateOrigin, Edition, FileId, ProcMacroKind};
use either::Either;
use hir_def::{
adt::{ReprData, VariantData},
adt::VariantData,
body::{BodyDiagnostic, SyntheticSyntax},
expr::{BindingAnnotation, LabelId, Pat, PatId},
generics::{TypeOrConstParamData, TypeParamProvenance},
item_tree::ItemTreeNode,
lang_item::LangItemTarget,
layout::{Layout, LayoutError, ReprOptions},
nameres::{self, diagnostics::DefDiagnostic},
per_ns::PerNs,
resolver::{HasResolver, Resolver},
@ -59,6 +60,7 @@ use hir_ty::{
all_super_traits, autoderef,
consteval::{unknown_const_as_generic, ComputedExpr, ConstEvalError, ConstExt},
diagnostics::BodyValidationDiagnostic,
layout::layout_of_ty,
method_resolution::{self, TyFingerprint},
primitive::UintTy,
traits::FnTrait,
@ -844,6 +846,10 @@ impl Field {
self.parent.variant_data(db).fields()[self.id].name.clone()
}
pub fn index(&self) -> usize {
u32::from(self.id.into_raw()) as usize
}
/// Returns the type as in the signature of the struct (i.e., with
/// placeholder types for type parameters). Only use this in the context of
/// the field definition.
@ -859,6 +865,10 @@ impl Field {
Type::new(db, var_id, ty)
}
pub fn layout(&self, db: &dyn HirDatabase) -> Result<Layout, LayoutError> {
layout_of_ty(db, &self.ty(db).ty)
}
pub fn parent_def(&self, _db: &dyn HirDatabase) -> VariantDef {
self.parent
}
@ -900,7 +910,7 @@ impl Struct {
Type::from_def(db, self.id)
}
pub fn repr(self, db: &dyn HirDatabase) -> Option<ReprData> {
pub fn repr(self, db: &dyn HirDatabase) -> Option<ReprOptions> {
db.struct_data(self.id).repr.clone()
}
@ -1076,6 +1086,13 @@ impl Adt {
})
}
pub fn layout(self, db: &dyn HirDatabase) -> Result<Layout, LayoutError> {
if db.generic_params(self.into()).iter().count() != 0 {
return Err(LayoutError::HasPlaceholder);
}
db.layout_of_adt(self.into(), Substitution::empty(Interner))
}
/// Turns this ADT into a type. Any type parameters of the ADT will be
/// turned into unknown types, which is good for e.g. finding the most
/// general set of completions, but will not look very nice when printed.
@ -3031,7 +3048,7 @@ impl Type {
let adt = adt_id.into();
match adt {
Adt::Struct(s) => matches!(s.repr(db), Some(ReprData { packed: true, .. })),
Adt::Struct(s) => s.repr(db).unwrap_or_default().pack.is_some(),
_ => false,
}
}

View file

@ -2,7 +2,10 @@
use std::fmt::Display;
use either::Either;
use hir::{AsAssocItem, AttributeTemplate, HasAttrs, HasSource, HirDisplay, Semantics, TypeInfo};
use hir::{
db::HirDatabase, Adt, AsAssocItem, AttributeTemplate, HasAttrs, HasSource, HirDisplay,
Semantics, TypeInfo,
};
use ide_db::{
base_db::SourceDatabase,
defs::Definition,
@ -388,10 +391,30 @@ pub(super) fn definition(
let mod_path = definition_mod_path(db, &def);
let (label, docs) = match def {
Definition::Macro(it) => label_and_docs(db, it),
Definition::Field(it) => label_and_docs(db, it),
Definition::Field(it) => label_and_layout_info_and_docs(db, it, |&it| {
let var_def = it.parent_def(db);
let id = it.index();
let layout = it.layout(db).ok()?;
let offset = match var_def {
hir::VariantDef::Struct(s) => {
let layout = Adt::from(s).layout(db).ok()?;
layout.fields.offset(id, &db.current_target_data_layout())
}
_ => return None,
};
Some(format!(
"size = {}, align = {}, offset = {}",
layout.size.bytes(),
layout.align.abi.bytes(),
offset.bytes()
))
}),
Definition::Module(it) => label_and_docs(db, it),
Definition::Function(it) => label_and_docs(db, it),
Definition::Adt(it) => label_and_docs(db, it),
Definition::Adt(it) => label_and_layout_info_and_docs(db, it, |&it| {
let layout = it.layout(db).ok()?;
Some(format!("size = {}, align = {}", layout.size.bytes(), layout.align.abi.bytes()))
}),
Definition::Variant(it) => label_value_and_docs(db, it, |&it| {
if !it.parent_enum(db).is_data_carrying(db) {
match it.eval(db) {
@ -489,6 +512,25 @@ where
(label, docs)
}
fn label_and_layout_info_and_docs<D, E, V>(
db: &RootDatabase,
def: D,
value_extractor: E,
) -> (String, Option<hir::Documentation>)
where
D: HasAttrs + HirDisplay,
E: Fn(&D) -> Option<V>,
V: Display,
{
let label = if let Some(value) = value_extractor(&def) {
format!("{} // {}", def.display(db), value)
} else {
def.display(db).to_string()
};
let docs = def.attrs(db).docs();
(label, docs)
}
fn label_value_and_docs<D, E, V>(
db: &RootDatabase,
def: D,

View file

@ -522,6 +522,27 @@ fn main() { }
);
}
#[test]
fn hover_field_offset() {
// Hovering over the field when instantiating
check(
r#"
struct Foo { fiel$0d_a: u8, field_b: i32, field_c: i16 }
"#,
expect![[r#"
*field_a*
```rust
test::Foo
```
```rust
field_a: u8 // size = 1, align = 1, offset = 6
```
"#]],
);
}
#[test]
fn hover_shows_struct_field_info() {
// Hovering over the field when instantiating
@ -534,16 +555,16 @@ fn main() {
}
"#,
expect![[r#"
*field_a*
*field_a*
```rust
test::Foo
```
```rust
test::Foo
```
```rust
field_a: u32
```
"#]],
```rust
field_a: u32 // size = 4, align = 4, offset = 0
```
"#]],
);
// Hovering over the field in the definition
@ -556,16 +577,16 @@ fn main() {
}
"#,
expect![[r#"
*field_a*
*field_a*
```rust
test::Foo
```
```rust
test::Foo
```
```rust
field_a: u32
```
"#]],
```rust
field_a: u32 // size = 4, align = 4, offset = 0
```
"#]],
);
}
@ -1508,30 +1529,30 @@ struct Bar;
fn foo() { let bar = Ba$0r; }
"#,
expect![[r##"
*Bar*
expect![[r#"
*Bar*
```rust
test
```
```rust
test
```
```rust
struct Bar
```
```rust
struct Bar // size = 0, align = 1
```
---
---
This is an example
multiline doc
This is an example
multiline doc
# Example
# Example
```
let five = 5;
```
let five = 5;
assert_eq!(6, my_crate::add_one(5));
```
"##]],
assert_eq!(6, my_crate::add_one(5));
```
"#]],
);
}
@ -1545,20 +1566,20 @@ struct Bar;
fn foo() { let bar = Ba$0r; }
"#,
expect![[r#"
*Bar*
*Bar*
```rust
test
```
```rust
test
```
```rust
struct Bar
```
```rust
struct Bar // size = 0, align = 1
```
---
---
bar docs
"#]],
bar docs
"#]],
);
}
@ -1574,22 +1595,22 @@ struct Bar;
fn foo() { let bar = Ba$0r; }
"#,
expect![[r#"
*Bar*
*Bar*
```rust
test
```
```rust
test
```
```rust
struct Bar
```
```rust
struct Bar // size = 0, align = 1
```
---
---
bar docs 0
bar docs 1
bar docs 2
"#]],
bar docs 0
bar docs 1
bar docs 2
"#]],
);
}
@ -1602,20 +1623,20 @@ pub struct Foo;
pub struct B$0ar
"#,
expect![[r#"
*Bar*
*Bar*
```rust
test
```
```rust
test
```
```rust
pub struct Bar
```
```rust
pub struct Bar // size = 0, align = 1
```
---
---
[external](https://www.google.com)
"#]],
[external](https://www.google.com)
"#]],
);
}
@ -1629,20 +1650,20 @@ pub struct Foo;
pub struct B$0ar
"#,
expect![[r#"
*Bar*
*Bar*
```rust
test
```
```rust
test
```
```rust
pub struct Bar
```
```rust
pub struct Bar // size = 0, align = 1
```
---
---
[baz](Baz)
"#]],
[baz](Baz)
"#]],
);
}
@ -2960,7 +2981,7 @@ fn main() {
```
```rust
f: i32
f: i32 // size = 4, align = 4, offset = 0
```
"#]],
);
@ -4203,20 +4224,20 @@ pub fn gimme() -> theitem::TheItem {
}
"#,
expect![[r#"
*[`TheItem`]*
*[`TheItem`]*
```rust
test::theitem
```
```rust
test::theitem
```
```rust
pub struct TheItem
```
```rust
pub struct TheItem // size = 0, align = 1
```
---
---
This is the item. Cool!
"#]],
This is the item. Cool!
"#]],
);
}
@ -4351,20 +4372,20 @@ mod string {
}
"#,
expect![[r#"
*String*
*String*
```rust
main
```
```rust
main
```
```rust
struct String
```
```rust
struct String // size = 0, align = 1
```
---
---
Custom `String` type.
"#]],
Custom `String` type.
"#]],
)
}
@ -5025,7 +5046,7 @@ foo_macro!(
```
```rust
pub struct Foo
pub struct Foo // size = 0, align = 1
```
---
@ -5040,7 +5061,7 @@ fn hover_intra_in_attr() {
check(
r#"
#[doc = "Doc comment for [`Foo$0`]"]
pub struct Foo;
pub struct Foo(i32);
"#,
expect![[r#"
*[`Foo`]*
@ -5050,7 +5071,7 @@ pub struct Foo;
```
```rust
pub struct Foo
pub struct Foo // size = 4, align = 4
```
---

View file

@ -86,6 +86,14 @@ impl<T, V> ArenaMap<Idx<T>, V> {
self.v.iter().enumerate().filter_map(|(idx, o)| Some((Self::from_idx(idx), o.as_ref()?)))
}
/// Returns an iterator over the arena indexes and values in the map.
pub fn iter_mut(&mut self) -> impl Iterator<Item = (Idx<T>, &mut V)> {
self.v
.iter_mut()
.enumerate()
.filter_map(|(idx, o)| Some((Self::from_idx(idx), o.as_mut()?)))
}
/// Gets the given key's corresponding entry in the map for in-place manipulation.
pub fn entry(&mut self, idx: Idx<T>) -> Entry<'_, Idx<T>, V> {
let idx = Self::to_idx(idx);