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firefox/third_party/rust/bindgen/ir/comp.rs
Daniel Baumann 5e9a113729
Adding upstream version 140.0.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
2025-06-25 09:37:52 +02:00

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//! Compound types (unions and structs) in our intermediate representation.
use itertools::Itertools;
use super::analysis::Sizedness;
use super::annotations::Annotations;
use super::context::{BindgenContext, FunctionId, ItemId, TypeId, VarId};
use super::dot::DotAttributes;
use super::item::{IsOpaque, Item};
use super::layout::Layout;
use super::template::TemplateParameters;
use super::traversal::{EdgeKind, Trace, Tracer};
use super::ty::RUST_DERIVE_IN_ARRAY_LIMIT;
use crate::clang;
use crate::codegen::struct_layout::{align_to, bytes_from_bits_pow2};
use crate::ir::derive::CanDeriveCopy;
use crate::parse::ParseError;
use crate::HashMap;
use crate::NonCopyUnionStyle;
use std::cmp;
use std::io;
use std::mem;
/// The kind of compound type.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub(crate) enum CompKind {
/// A struct.
Struct,
/// A union.
Union,
}
/// The kind of C++ method.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub(crate) enum MethodKind {
/// A constructor. We represent it as method for convenience, to avoid code
/// duplication.
Constructor,
/// A destructor.
Destructor,
/// A virtual destructor.
VirtualDestructor {
/// Whether it's pure virtual.
pure_virtual: bool,
},
/// A static method.
Static,
/// A normal method.
Normal,
/// A virtual method.
Virtual {
/// Whether it's pure virtual.
pure_virtual: bool,
},
}
impl MethodKind {
/// Is this a destructor method?
pub(crate) fn is_destructor(&self) -> bool {
matches!(
*self,
MethodKind::Destructor | MethodKind::VirtualDestructor { .. }
)
}
/// Is this a pure virtual method?
pub(crate) fn is_pure_virtual(&self) -> bool {
match *self {
MethodKind::Virtual { pure_virtual } |
MethodKind::VirtualDestructor { pure_virtual } => pure_virtual,
_ => false,
}
}
}
/// A struct representing a C++ method, either static, normal, or virtual.
#[derive(Debug)]
pub(crate) struct Method {
kind: MethodKind,
/// The signature of the method. Take into account this is not a `Type`
/// item, but a `Function` one.
///
/// This is tricky and probably this field should be renamed.
signature: FunctionId,
is_const: bool,
}
impl Method {
/// Construct a new `Method`.
pub(crate) fn new(
kind: MethodKind,
signature: FunctionId,
is_const: bool,
) -> Self {
Method {
kind,
signature,
is_const,
}
}
/// What kind of method is this?
pub(crate) fn kind(&self) -> MethodKind {
self.kind
}
/// Is this a constructor?
pub(crate) fn is_constructor(&self) -> bool {
self.kind == MethodKind::Constructor
}
/// Is this a virtual method?
pub(crate) fn is_virtual(&self) -> bool {
matches!(
self.kind,
MethodKind::Virtual { .. } | MethodKind::VirtualDestructor { .. }
)
}
/// Is this a static method?
pub(crate) fn is_static(&self) -> bool {
self.kind == MethodKind::Static
}
/// Get the ID for the `Function` signature for this method.
pub(crate) fn signature(&self) -> FunctionId {
self.signature
}
/// Is this a const qualified method?
pub(crate) fn is_const(&self) -> bool {
self.is_const
}
}
/// Methods common to the various field types.
pub(crate) trait FieldMethods {
/// Get the name of this field.
fn name(&self) -> Option<&str>;
/// Get the type of this field.
fn ty(&self) -> TypeId;
/// Get the comment for this field.
fn comment(&self) -> Option<&str>;
/// If this is a bitfield, how many bits does it need?
fn bitfield_width(&self) -> Option<u32>;
/// Is this feild declared public?
fn is_public(&self) -> bool;
/// Get the annotations for this field.
fn annotations(&self) -> &Annotations;
/// The offset of the field (in bits)
fn offset(&self) -> Option<usize>;
}
/// A contiguous set of logical bitfields that live within the same physical
/// allocation unit. See 9.2.4 [class.bit] in the C++ standard and [section
/// 2.4.II.1 in the Itanium C++
/// ABI](http://itanium-cxx-abi.github.io/cxx-abi/abi.html#class-types).
#[derive(Debug)]
pub(crate) struct BitfieldUnit {
nth: usize,
layout: Layout,
bitfields: Vec<Bitfield>,
}
impl BitfieldUnit {
/// Get the 1-based index of this bitfield unit within its containing
/// struct. Useful for generating a Rust struct's field name for this unit
/// of bitfields.
pub(crate) fn nth(&self) -> usize {
self.nth
}
/// Get the layout within which these bitfields reside.
pub(crate) fn layout(&self) -> Layout {
self.layout
}
/// Get the bitfields within this unit.
pub(crate) fn bitfields(&self) -> &[Bitfield] {
&self.bitfields
}
}
/// A struct representing a C++ field.
#[derive(Debug)]
pub(crate) enum Field {
/// A normal data member.
DataMember(FieldData),
/// A physical allocation unit containing many logical bitfields.
Bitfields(BitfieldUnit),
}
impl Field {
/// Get this field's layout.
pub(crate) fn layout(&self, ctx: &BindgenContext) -> Option<Layout> {
match *self {
Field::Bitfields(BitfieldUnit { layout, .. }) => Some(layout),
Field::DataMember(ref data) => {
ctx.resolve_type(data.ty).layout(ctx)
}
}
}
}
impl Trace for Field {
type Extra = ();
fn trace<T>(&self, _: &BindgenContext, tracer: &mut T, _: &())
where
T: Tracer,
{
match *self {
Field::DataMember(ref data) => {
tracer.visit_kind(data.ty.into(), EdgeKind::Field);
}
Field::Bitfields(BitfieldUnit { ref bitfields, .. }) => {
for bf in bitfields {
tracer.visit_kind(bf.ty().into(), EdgeKind::Field);
}
}
}
}
}
impl DotAttributes for Field {
fn dot_attributes<W>(
&self,
ctx: &BindgenContext,
out: &mut W,
) -> io::Result<()>
where
W: io::Write,
{
match *self {
Field::DataMember(ref data) => data.dot_attributes(ctx, out),
Field::Bitfields(BitfieldUnit {
layout,
ref bitfields,
..
}) => {
writeln!(
out,
r#"<tr>
<td>bitfield unit</td>
<td>
<table border="0">
<tr>
<td>unit.size</td><td>{}</td>
</tr>
<tr>
<td>unit.align</td><td>{}</td>
</tr>
"#,
layout.size, layout.align
)?;
for bf in bitfields {
bf.dot_attributes(ctx, out)?;
}
writeln!(out, "</table></td></tr>")
}
}
}
}
impl DotAttributes for FieldData {
fn dot_attributes<W>(
&self,
_ctx: &BindgenContext,
out: &mut W,
) -> io::Result<()>
where
W: io::Write,
{
writeln!(
out,
"<tr><td>{}</td><td>{:?}</td></tr>",
self.name().unwrap_or("(anonymous)"),
self.ty()
)
}
}
impl DotAttributes for Bitfield {
fn dot_attributes<W>(
&self,
_ctx: &BindgenContext,
out: &mut W,
) -> io::Result<()>
where
W: io::Write,
{
writeln!(
out,
"<tr><td>{} : {}</td><td>{:?}</td></tr>",
self.name().unwrap_or("(anonymous)"),
self.width(),
self.ty()
)
}
}
/// A logical bitfield within some physical bitfield allocation unit.
#[derive(Debug)]
pub(crate) struct Bitfield {
/// Index of the bit within this bitfield's allocation unit where this
/// bitfield's bits begin.
offset_into_unit: usize,
/// The field data for this bitfield.
data: FieldData,
/// Name of the generated Rust getter for this bitfield.
///
/// Should be assigned before codegen.
getter_name: Option<String>,
/// Name of the generated Rust setter for this bitfield.
///
/// Should be assigned before codegen.
setter_name: Option<String>,
}
impl Bitfield {
/// Construct a new bitfield.
fn new(offset_into_unit: usize, raw: RawField) -> Bitfield {
assert!(raw.bitfield_width().is_some());
Bitfield {
offset_into_unit,
data: raw.0,
getter_name: None,
setter_name: None,
}
}
/// Get the index of the bit within this bitfield's allocation unit where
/// this bitfield begins.
pub(crate) fn offset_into_unit(&self) -> usize {
self.offset_into_unit
}
/// Get the bit width of this bitfield.
pub(crate) fn width(&self) -> u32 {
self.data.bitfield_width().unwrap()
}
/// Name of the generated Rust getter for this bitfield.
///
/// Panics if called before assigning bitfield accessor names or if
/// this bitfield have no name.
pub(crate) fn getter_name(&self) -> &str {
assert!(
self.name().is_some(),
"`Bitfield::getter_name` called on anonymous field"
);
self.getter_name.as_ref().expect(
"`Bitfield::getter_name` should only be called after\
assigning bitfield accessor names",
)
}
/// Name of the generated Rust setter for this bitfield.
///
/// Panics if called before assigning bitfield accessor names or if
/// this bitfield have no name.
pub(crate) fn setter_name(&self) -> &str {
assert!(
self.name().is_some(),
"`Bitfield::setter_name` called on anonymous field"
);
self.setter_name.as_ref().expect(
"`Bitfield::setter_name` should only be called\
after assigning bitfield accessor names",
)
}
}
impl FieldMethods for Bitfield {
fn name(&self) -> Option<&str> {
self.data.name()
}
fn ty(&self) -> TypeId {
self.data.ty()
}
fn comment(&self) -> Option<&str> {
self.data.comment()
}
fn bitfield_width(&self) -> Option<u32> {
self.data.bitfield_width()
}
fn is_public(&self) -> bool {
self.data.is_public()
}
fn annotations(&self) -> &Annotations {
self.data.annotations()
}
fn offset(&self) -> Option<usize> {
self.data.offset()
}
}
/// A raw field might be either of a plain data member or a bitfield within a
/// bitfield allocation unit, but we haven't processed it and determined which
/// yet (which would involve allocating it into a bitfield unit if it is a
/// bitfield).
#[derive(Debug)]
struct RawField(FieldData);
impl RawField {
/// Construct a new `RawField`.
fn new(
name: Option<String>,
ty: TypeId,
comment: Option<String>,
annotations: Option<Annotations>,
bitfield_width: Option<u32>,
public: bool,
offset: Option<usize>,
) -> RawField {
RawField(FieldData {
name,
ty,
comment,
annotations: annotations.unwrap_or_default(),
bitfield_width,
public,
offset,
})
}
}
impl FieldMethods for RawField {
fn name(&self) -> Option<&str> {
self.0.name()
}
fn ty(&self) -> TypeId {
self.0.ty()
}
fn comment(&self) -> Option<&str> {
self.0.comment()
}
fn bitfield_width(&self) -> Option<u32> {
self.0.bitfield_width()
}
fn is_public(&self) -> bool {
self.0.is_public()
}
fn annotations(&self) -> &Annotations {
self.0.annotations()
}
fn offset(&self) -> Option<usize> {
self.0.offset()
}
}
/// Convert the given ordered set of raw fields into a list of either plain data
/// members, and/or bitfield units containing multiple bitfields.
///
/// If we do not have the layout for a bitfield's type, then we can't reliably
/// compute its allocation unit. In such cases, we return an error.
fn raw_fields_to_fields_and_bitfield_units<I>(
ctx: &BindgenContext,
raw_fields: I,
packed: bool,
) -> Result<(Vec<Field>, bool), ()>
where
I: IntoIterator<Item = RawField>,
{
let mut raw_fields = raw_fields.into_iter().fuse().peekable();
let mut fields = vec![];
let mut bitfield_unit_count = 0;
loop {
// While we have plain old data members, just keep adding them to our
// resulting fields. We introduce a scope here so that we can use
// `raw_fields` again after the `by_ref` iterator adaptor is dropped.
{
let non_bitfields = raw_fields
.by_ref()
.peeking_take_while(|f| f.bitfield_width().is_none())
.map(|f| Field::DataMember(f.0));
fields.extend(non_bitfields);
}
// Now gather all the consecutive bitfields. Only consecutive bitfields
// may potentially share a bitfield allocation unit with each other in
// the Itanium C++ ABI.
let mut bitfields = raw_fields
.by_ref()
.peeking_take_while(|f| f.bitfield_width().is_some())
.peekable();
if bitfields.peek().is_none() {
break;
}
bitfields_to_allocation_units(
ctx,
&mut bitfield_unit_count,
&mut fields,
bitfields,
packed,
)?;
}
assert!(
raw_fields.next().is_none(),
"The above loop should consume all items in `raw_fields`"
);
Ok((fields, bitfield_unit_count != 0))
}
/// Given a set of contiguous raw bitfields, group and allocate them into
/// (potentially multiple) bitfield units.
fn bitfields_to_allocation_units<E, I>(
ctx: &BindgenContext,
bitfield_unit_count: &mut usize,
fields: &mut E,
raw_bitfields: I,
packed: bool,
) -> Result<(), ()>
where
E: Extend<Field>,
I: IntoIterator<Item = RawField>,
{
assert!(ctx.collected_typerefs());
// NOTE: What follows is reverse-engineered from LLVM's
// lib/AST/RecordLayoutBuilder.cpp
//
// FIXME(emilio): There are some differences between Microsoft and the
// Itanium ABI, but we'll ignore those and stick to Itanium for now.
//
// Also, we need to handle packed bitfields and stuff.
//
// TODO(emilio): Take into account C++'s wide bitfields, and
// packing, sigh.
fn flush_allocation_unit<E>(
fields: &mut E,
bitfield_unit_count: &mut usize,
unit_size_in_bits: usize,
unit_align_in_bits: usize,
bitfields: Vec<Bitfield>,
packed: bool,
) where
E: Extend<Field>,
{
*bitfield_unit_count += 1;
let align = if packed {
1
} else {
bytes_from_bits_pow2(unit_align_in_bits)
};
let size = align_to(unit_size_in_bits, 8) / 8;
let layout = Layout::new(size, align);
fields.extend(Some(Field::Bitfields(BitfieldUnit {
nth: *bitfield_unit_count,
layout,
bitfields,
})));
}
let mut max_align = 0;
let mut unfilled_bits_in_unit = 0;
let mut unit_size_in_bits = 0;
let mut unit_align = 0;
let mut bitfields_in_unit = vec![];
// TODO(emilio): Determine this from attributes or pragma ms_struct
// directives. Also, perhaps we should check if the target is MSVC?
const is_ms_struct: bool = false;
for bitfield in raw_bitfields {
let bitfield_width = bitfield.bitfield_width().unwrap() as usize;
let bitfield_layout =
ctx.resolve_type(bitfield.ty()).layout(ctx).ok_or(())?;
let bitfield_size = bitfield_layout.size;
let bitfield_align = bitfield_layout.align;
let mut offset = unit_size_in_bits;
if !packed {
if is_ms_struct {
if unit_size_in_bits != 0 &&
(bitfield_width == 0 ||
bitfield_width > unfilled_bits_in_unit)
{
// We've reached the end of this allocation unit, so flush it
// and its bitfields.
unit_size_in_bits =
align_to(unit_size_in_bits, unit_align * 8);
flush_allocation_unit(
fields,
bitfield_unit_count,
unit_size_in_bits,
unit_align,
mem::take(&mut bitfields_in_unit),
packed,
);
// Now we're working on a fresh bitfield allocation unit, so reset
// the current unit size and alignment.
offset = 0;
unit_align = 0;
}
} else if offset != 0 &&
(bitfield_width == 0 ||
(offset & (bitfield_align * 8 - 1)) + bitfield_width >
bitfield_size * 8)
{
offset = align_to(offset, bitfield_align * 8);
}
}
// According to the x86[-64] ABI spec: "Unnamed bit-fields types do not
// affect the alignment of a structure or union". This makes sense: such
// bit-fields are only used for padding, and we can't perform an
// un-aligned read of something we can't read because we can't even name
// it.
if bitfield.name().is_some() {
max_align = cmp::max(max_align, bitfield_align);
// NB: The `bitfield_width` here is completely, absolutely
// intentional. Alignment of the allocation unit is based on the
// maximum bitfield width, not (directly) on the bitfields' types'
// alignment.
unit_align = cmp::max(unit_align, bitfield_width);
}
// Always keep all bitfields around. While unnamed bitifields are used
// for padding (and usually not needed hereafter), large unnamed
// bitfields over their types size cause weird allocation size behavior from clang.
// Therefore, all bitfields needed to be kept around in order to check for this
// and make the struct opaque in this case
bitfields_in_unit.push(Bitfield::new(offset, bitfield));
unit_size_in_bits = offset + bitfield_width;
// Compute what the physical unit's final size would be given what we
// have seen so far, and use that to compute how many bits are still
// available in the unit.
let data_size = align_to(unit_size_in_bits, bitfield_align * 8);
unfilled_bits_in_unit = data_size - unit_size_in_bits;
}
if unit_size_in_bits != 0 {
// Flush the last allocation unit and its bitfields.
flush_allocation_unit(
fields,
bitfield_unit_count,
unit_size_in_bits,
unit_align,
bitfields_in_unit,
packed,
);
}
Ok(())
}
/// A compound structure's fields are initially raw, and have bitfields that
/// have not been grouped into allocation units. During this time, the fields
/// are mutable and we build them up during parsing.
///
/// Then, once resolving typerefs is completed, we compute all structs' fields'
/// bitfield allocation units, and they remain frozen and immutable forever
/// after.
#[derive(Debug)]
enum CompFields {
Before(Vec<RawField>),
After {
fields: Vec<Field>,
has_bitfield_units: bool,
},
Error,
}
impl Default for CompFields {
fn default() -> CompFields {
CompFields::Before(vec![])
}
}
impl CompFields {
fn append_raw_field(&mut self, raw: RawField) {
match *self {
CompFields::Before(ref mut raws) => {
raws.push(raw);
}
_ => {
panic!(
"Must not append new fields after computing bitfield allocation units"
);
}
}
}
fn compute_bitfield_units(&mut self, ctx: &BindgenContext, packed: bool) {
let raws = match *self {
CompFields::Before(ref mut raws) => mem::take(raws),
_ => {
panic!("Already computed bitfield units");
}
};
let result = raw_fields_to_fields_and_bitfield_units(ctx, raws, packed);
match result {
Ok((fields, has_bitfield_units)) => {
*self = CompFields::After {
fields,
has_bitfield_units,
};
}
Err(()) => {
*self = CompFields::Error;
}
}
}
fn deanonymize_fields(&mut self, ctx: &BindgenContext, methods: &[Method]) {
let fields = match *self {
CompFields::After { ref mut fields, .. } => fields,
// Nothing to do here.
CompFields::Error => return,
CompFields::Before(_) => {
panic!("Not yet computed bitfield units.");
}
};
fn has_method(
methods: &[Method],
ctx: &BindgenContext,
name: &str,
) -> bool {
methods.iter().any(|method| {
let method_name = ctx.resolve_func(method.signature()).name();
method_name == name || ctx.rust_mangle(method_name) == name
})
}
struct AccessorNamesPair {
getter: String,
setter: String,
}
let mut accessor_names: HashMap<String, AccessorNamesPair> = fields
.iter()
.flat_map(|field| match *field {
Field::Bitfields(ref bu) => &*bu.bitfields,
Field::DataMember(_) => &[],
})
.filter_map(|bitfield| bitfield.name())
.map(|bitfield_name| {
let bitfield_name = bitfield_name.to_string();
let getter = {
let mut getter =
ctx.rust_mangle(&bitfield_name).to_string();
if has_method(methods, ctx, &getter) {
getter.push_str("_bindgen_bitfield");
}
getter
};
let setter = {
let setter = format!("set_{}", bitfield_name);
let mut setter = ctx.rust_mangle(&setter).to_string();
if has_method(methods, ctx, &setter) {
setter.push_str("_bindgen_bitfield");
}
setter
};
(bitfield_name, AccessorNamesPair { getter, setter })
})
.collect();
let mut anon_field_counter = 0;
for field in fields.iter_mut() {
match *field {
Field::DataMember(FieldData { ref mut name, .. }) => {
if name.is_some() {
continue;
}
anon_field_counter += 1;
*name = Some(format!(
"{}{}",
ctx.options().anon_fields_prefix,
anon_field_counter
));
}
Field::Bitfields(ref mut bu) => {
for bitfield in &mut bu.bitfields {
if bitfield.name().is_none() {
continue;
}
if let Some(AccessorNamesPair { getter, setter }) =
accessor_names.remove(bitfield.name().unwrap())
{
bitfield.getter_name = Some(getter);
bitfield.setter_name = Some(setter);
}
}
}
}
}
}
}
impl Trace for CompFields {
type Extra = ();
fn trace<T>(&self, context: &BindgenContext, tracer: &mut T, _: &())
where
T: Tracer,
{
match *self {
CompFields::Error => {}
CompFields::Before(ref fields) => {
for f in fields {
tracer.visit_kind(f.ty().into(), EdgeKind::Field);
}
}
CompFields::After { ref fields, .. } => {
for f in fields {
f.trace(context, tracer, &());
}
}
}
}
}
/// Common data shared across different field types.
#[derive(Clone, Debug)]
pub(crate) struct FieldData {
/// The name of the field, empty if it's an unnamed bitfield width.
name: Option<String>,
/// The inner type.
ty: TypeId,
/// The doc comment on the field if any.
comment: Option<String>,
/// Annotations for this field, or the default.
annotations: Annotations,
/// If this field is a bitfield, and how many bits does it contain if it is.
bitfield_width: Option<u32>,
/// If the C++ field is declared `public`
public: bool,
/// The offset of the field (in bits)
offset: Option<usize>,
}
impl FieldMethods for FieldData {
fn name(&self) -> Option<&str> {
self.name.as_deref()
}
fn ty(&self) -> TypeId {
self.ty
}
fn comment(&self) -> Option<&str> {
self.comment.as_deref()
}
fn bitfield_width(&self) -> Option<u32> {
self.bitfield_width
}
fn is_public(&self) -> bool {
self.public
}
fn annotations(&self) -> &Annotations {
&self.annotations
}
fn offset(&self) -> Option<usize> {
self.offset
}
}
/// The kind of inheritance a base class is using.
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) enum BaseKind {
/// Normal inheritance, like:
///
/// ```cpp
/// class A : public B {};
/// ```
Normal,
/// Virtual inheritance, like:
///
/// ```cpp
/// class A: public virtual B {};
/// ```
Virtual,
}
/// A base class.
#[derive(Clone, Debug)]
pub(crate) struct Base {
/// The type of this base class.
pub(crate) ty: TypeId,
/// The kind of inheritance we're doing.
pub(crate) kind: BaseKind,
/// Name of the field in which this base should be stored.
pub(crate) field_name: String,
/// Whether this base is inherited from publically.
pub(crate) is_pub: bool,
}
impl Base {
/// Whether this base class is inheriting virtually.
pub(crate) fn is_virtual(&self) -> bool {
self.kind == BaseKind::Virtual
}
/// Whether this base class should have it's own field for storage.
pub(crate) fn requires_storage(&self, ctx: &BindgenContext) -> bool {
// Virtual bases are already taken into account by the vtable
// pointer.
//
// FIXME(emilio): Is this always right?
if self.is_virtual() {
return false;
}
// NB: We won't include zero-sized types in our base chain because they
// would contribute to our size given the dummy field we insert for
// zero-sized types.
if self.ty.is_zero_sized(ctx) {
return false;
}
true
}
/// Whether this base is inherited from publically.
pub(crate) fn is_public(&self) -> bool {
self.is_pub
}
}
/// A compound type.
///
/// Either a struct or union, a compound type is built up from the combination
/// of fields which also are associated with their own (potentially compound)
/// type.
#[derive(Debug)]
pub(crate) struct CompInfo {
/// Whether this is a struct or a union.
kind: CompKind,
/// The members of this struct or union.
fields: CompFields,
/// The abstract template parameters of this class. Note that these are NOT
/// concrete template arguments, and should always be a
/// `Type(TypeKind::TypeParam(name))`. For concrete template arguments, see
/// `TypeKind::TemplateInstantiation`.
template_params: Vec<TypeId>,
/// The method declarations inside this class, if in C++ mode.
methods: Vec<Method>,
/// The different constructors this struct or class contains.
constructors: Vec<FunctionId>,
/// The destructor of this type. The bool represents whether this destructor
/// is virtual.
destructor: Option<(MethodKind, FunctionId)>,
/// Vector of classes this one inherits from.
base_members: Vec<Base>,
/// The inner types that were declared inside this class, in something like:
///
/// class Foo {
/// typedef int FooTy;
/// struct Bar {
/// int baz;
/// };
/// }
///
/// static Foo::Bar const = {3};
inner_types: Vec<TypeId>,
/// Set of static constants declared inside this class.
inner_vars: Vec<VarId>,
/// Whether this type should generate an vtable (TODO: Should be able to
/// look at the virtual methods and ditch this field).
has_own_virtual_method: bool,
/// Whether this type has destructor.
has_destructor: bool,
/// Whether this type has a base type with more than one member.
///
/// TODO: We should be able to compute this.
has_nonempty_base: bool,
/// If this type has a template parameter which is not a type (e.g.: a
/// size_t)
has_non_type_template_params: bool,
/// Whether this type has a bit field member whose width couldn't be
/// evaluated (e.g. if it depends on a template parameter). We generate an
/// opaque type in this case.
has_unevaluable_bit_field_width: bool,
/// Whether we saw `__attribute__((packed))` on or within this type.
packed_attr: bool,
/// Used to know if we've found an opaque attribute that could cause us to
/// generate a type with invalid layout. This is explicitly used to avoid us
/// generating bad alignments when parsing types like max_align_t.
///
/// It's not clear what the behavior should be here, if generating the item
/// and pray, or behave as an opaque type.
found_unknown_attr: bool,
/// Used to indicate when a struct has been forward declared. Usually used
/// in headers so that APIs can't modify them directly.
is_forward_declaration: bool,
}
impl CompInfo {
/// Construct a new compound type.
pub(crate) fn new(kind: CompKind) -> Self {
CompInfo {
kind,
fields: CompFields::default(),
template_params: vec![],
methods: vec![],
constructors: vec![],
destructor: None,
base_members: vec![],
inner_types: vec![],
inner_vars: vec![],
has_own_virtual_method: false,
has_destructor: false,
has_nonempty_base: false,
has_non_type_template_params: false,
has_unevaluable_bit_field_width: false,
packed_attr: false,
found_unknown_attr: false,
is_forward_declaration: false,
}
}
/// Compute the layout of this type.
///
/// This is called as a fallback under some circumstances where LLVM doesn't
/// give us the correct layout.
///
/// If we're a union without known layout, we try to compute it from our
/// members. This is not ideal, but clang fails to report the size for these
/// kind of unions, see test/headers/template_union.hpp
pub(crate) fn layout(&self, ctx: &BindgenContext) -> Option<Layout> {
// We can't do better than clang here, sorry.
if self.kind == CompKind::Struct {
return None;
}
// By definition, we don't have the right layout information here if
// we're a forward declaration.
if self.is_forward_declaration() {
return None;
}
// empty union case
if !self.has_fields() {
return None;
}
let mut max_size = 0;
// Don't allow align(0)
let mut max_align = 1;
self.each_known_field_layout(ctx, |layout| {
max_size = cmp::max(max_size, layout.size);
max_align = cmp::max(max_align, layout.align);
});
Some(Layout::new(max_size, max_align))
}
/// Get this type's set of fields.
pub(crate) fn fields(&self) -> &[Field] {
match self.fields {
CompFields::Error => &[],
CompFields::After { ref fields, .. } => fields,
CompFields::Before(..) => {
panic!("Should always have computed bitfield units first");
}
}
}
fn has_fields(&self) -> bool {
match self.fields {
CompFields::Error => false,
CompFields::After { ref fields, .. } => !fields.is_empty(),
CompFields::Before(ref raw_fields) => !raw_fields.is_empty(),
}
}
fn each_known_field_layout(
&self,
ctx: &BindgenContext,
mut callback: impl FnMut(Layout),
) {
match self.fields {
CompFields::Error => {}
CompFields::After { ref fields, .. } => {
for field in fields.iter() {
if let Some(layout) = field.layout(ctx) {
callback(layout);
}
}
}
CompFields::Before(ref raw_fields) => {
for field in raw_fields.iter() {
let field_ty = ctx.resolve_type(field.0.ty);
if let Some(layout) = field_ty.layout(ctx) {
callback(layout);
}
}
}
}
}
fn has_bitfields(&self) -> bool {
match self.fields {
CompFields::Error => false,
CompFields::After {
has_bitfield_units, ..
} => has_bitfield_units,
CompFields::Before(_) => {
panic!("Should always have computed bitfield units first");
}
}
}
/// Returns whether we have a too large bitfield unit, in which case we may
/// not be able to derive some of the things we should be able to normally
/// derive.
pub(crate) fn has_too_large_bitfield_unit(&self) -> bool {
if !self.has_bitfields() {
return false;
}
self.fields().iter().any(|field| match *field {
Field::DataMember(..) => false,
Field::Bitfields(ref unit) => {
unit.layout.size > RUST_DERIVE_IN_ARRAY_LIMIT
}
})
}
/// Does this type have any template parameters that aren't types
/// (e.g. int)?
pub(crate) fn has_non_type_template_params(&self) -> bool {
self.has_non_type_template_params
}
/// Do we see a virtual function during parsing?
/// Get the has_own_virtual_method boolean.
pub(crate) fn has_own_virtual_method(&self) -> bool {
self.has_own_virtual_method
}
/// Did we see a destructor when parsing this type?
pub(crate) fn has_own_destructor(&self) -> bool {
self.has_destructor
}
/// Get this type's set of methods.
pub(crate) fn methods(&self) -> &[Method] {
&self.methods
}
/// Get this type's set of constructors.
pub(crate) fn constructors(&self) -> &[FunctionId] {
&self.constructors
}
/// Get this type's destructor.
pub(crate) fn destructor(&self) -> Option<(MethodKind, FunctionId)> {
self.destructor
}
/// What kind of compound type is this?
pub(crate) fn kind(&self) -> CompKind {
self.kind
}
/// Is this a union?
pub(crate) fn is_union(&self) -> bool {
self.kind() == CompKind::Union
}
/// The set of types that this one inherits from.
pub(crate) fn base_members(&self) -> &[Base] {
&self.base_members
}
/// Construct a new compound type from a Clang type.
pub(crate) fn from_ty(
potential_id: ItemId,
ty: &clang::Type,
location: Option<clang::Cursor>,
ctx: &mut BindgenContext,
) -> Result<Self, ParseError> {
use clang_sys::*;
assert!(
ty.template_args().is_none(),
"We handle template instantiations elsewhere"
);
let mut cursor = ty.declaration();
let mut kind = Self::kind_from_cursor(&cursor);
if kind.is_err() {
if let Some(location) = location {
kind = Self::kind_from_cursor(&location);
cursor = location;
}
}
let kind = kind?;
debug!("CompInfo::from_ty({:?}, {:?})", kind, cursor);
let mut ci = CompInfo::new(kind);
ci.is_forward_declaration =
location.map_or(true, |cur| match cur.kind() {
CXCursor_ParmDecl => true,
CXCursor_StructDecl | CXCursor_UnionDecl |
CXCursor_ClassDecl => !cur.is_definition(),
_ => false,
});
let mut maybe_anonymous_struct_field = None;
cursor.visit(|cur| {
if cur.kind() != CXCursor_FieldDecl {
if let Some((ty, clang_ty, public, offset)) =
maybe_anonymous_struct_field.take()
{
if cur.kind() == CXCursor_TypedefDecl &&
cur.typedef_type().unwrap().canonical_type() ==
clang_ty
{
// Typedefs of anonymous structs appear later in the ast
// than the struct itself, that would otherwise be an
// anonymous field. Detect that case here, and do
// nothing.
} else {
let field = RawField::new(
None, ty, None, None, None, public, offset,
);
ci.fields.append_raw_field(field);
}
}
}
match cur.kind() {
CXCursor_FieldDecl => {
if let Some((ty, clang_ty, public, offset)) =
maybe_anonymous_struct_field.take()
{
let mut used = false;
cur.visit(|child| {
if child.cur_type() == clang_ty {
used = true;
}
CXChildVisit_Continue
});
if !used {
let field = RawField::new(
None, ty, None, None, None, public, offset,
);
ci.fields.append_raw_field(field);
}
}
let bit_width = if cur.is_bit_field() {
let width = cur.bit_width();
// Make opaque type if the bit width couldn't be
// evaluated.
if width.is_none() {
ci.has_unevaluable_bit_field_width = true;
return CXChildVisit_Break;
}
width
} else {
None
};
let field_type = Item::from_ty_or_ref(
cur.cur_type(),
cur,
Some(potential_id),
ctx,
);
let comment = cur.raw_comment();
let annotations = Annotations::new(&cur);
let name = cur.spelling();
let is_public = cur.public_accessible();
let offset = cur.offset_of_field().ok();
// Name can be empty if there are bitfields, for example,
// see tests/headers/struct_with_bitfields.h
assert!(
!name.is_empty() || bit_width.is_some(),
"Empty field name?"
);
let name = if name.is_empty() { None } else { Some(name) };
let field = RawField::new(
name,
field_type,
comment,
annotations,
bit_width,
is_public,
offset,
);
ci.fields.append_raw_field(field);
// No we look for things like attributes and stuff.
cur.visit(|cur| {
if cur.kind() == CXCursor_UnexposedAttr {
ci.found_unknown_attr = true;
}
CXChildVisit_Continue
});
}
CXCursor_UnexposedAttr => {
ci.found_unknown_attr = true;
}
CXCursor_EnumDecl |
CXCursor_TypeAliasDecl |
CXCursor_TypeAliasTemplateDecl |
CXCursor_TypedefDecl |
CXCursor_StructDecl |
CXCursor_UnionDecl |
CXCursor_ClassTemplate |
CXCursor_ClassDecl => {
// We can find non-semantic children here, clang uses a
// StructDecl to note incomplete structs that haven't been
// forward-declared before, see [1].
//
// Also, clang seems to scope struct definitions inside
// unions, and other named struct definitions inside other
// structs to the whole translation unit.
//
// Let's just assume that if the cursor we've found is a
// definition, it's a valid inner type.
//
// [1]: https://github.com/rust-lang/rust-bindgen/issues/482
let is_inner_struct =
cur.semantic_parent() == cursor || cur.is_definition();
if !is_inner_struct {
return CXChildVisit_Continue;
}
// Even if this is a definition, we may not be the semantic
// parent, see #1281.
let inner = Item::parse(cur, Some(potential_id), ctx)
.expect("Inner ClassDecl");
// If we avoided recursion parsing this type (in
// `Item::from_ty_with_id()`), then this might not be a
// valid type ID, so check and gracefully handle this.
if ctx.resolve_item_fallible(inner).is_some() {
let inner = inner.expect_type_id(ctx);
ci.inner_types.push(inner);
// A declaration of an union or a struct without name
// could also be an unnamed field, unfortunately.
if cur.is_anonymous() && cur.kind() != CXCursor_EnumDecl
{
let ty = cur.cur_type();
let public = cur.public_accessible();
let offset = cur.offset_of_field().ok();
maybe_anonymous_struct_field =
Some((inner, ty, public, offset));
}
}
}
CXCursor_PackedAttr => {
ci.packed_attr = true;
}
CXCursor_TemplateTypeParameter => {
let param = Item::type_param(None, cur, ctx).expect(
"Item::type_param should't fail when pointing \
at a TemplateTypeParameter",
);
ci.template_params.push(param);
}
CXCursor_CXXBaseSpecifier => {
let is_virtual_base = cur.is_virtual_base();
ci.has_own_virtual_method |= is_virtual_base;
let kind = if is_virtual_base {
BaseKind::Virtual
} else {
BaseKind::Normal
};
let field_name = match ci.base_members.len() {
0 => "_base".into(),
n => format!("_base_{}", n),
};
let type_id =
Item::from_ty_or_ref(cur.cur_type(), cur, None, ctx);
ci.base_members.push(Base {
ty: type_id,
kind,
field_name,
is_pub: cur.access_specifier() ==
clang_sys::CX_CXXPublic,
});
}
CXCursor_Constructor | CXCursor_Destructor |
CXCursor_CXXMethod => {
let is_virtual = cur.method_is_virtual();
let is_static = cur.method_is_static();
debug_assert!(!(is_static && is_virtual), "How?");
ci.has_destructor |= cur.kind() == CXCursor_Destructor;
ci.has_own_virtual_method |= is_virtual;
// This used to not be here, but then I tried generating
// stylo bindings with this (without path filters), and
// cried a lot with a method in gfx/Point.h
// (ToUnknownPoint), that somehow was causing the same type
// to be inserted in the map two times.
//
// I couldn't make a reduced test case, but anyway...
// Methods of template functions not only used to be inlined,
// but also instantiated, and we wouldn't be able to call
// them, so just bail out.
if !ci.template_params.is_empty() {
return CXChildVisit_Continue;
}
// NB: This gets us an owned `Function`, not a
// `FunctionSig`.
let signature =
match Item::parse(cur, Some(potential_id), ctx) {
Ok(item)
if ctx
.resolve_item(item)
.kind()
.is_function() =>
{
item
}
_ => return CXChildVisit_Continue,
};
let signature = signature.expect_function_id(ctx);
match cur.kind() {
CXCursor_Constructor => {
ci.constructors.push(signature);
}
CXCursor_Destructor => {
let kind = if is_virtual {
MethodKind::VirtualDestructor {
pure_virtual: cur.method_is_pure_virtual(),
}
} else {
MethodKind::Destructor
};
ci.destructor = Some((kind, signature));
}
CXCursor_CXXMethod => {
let is_const = cur.method_is_const();
let method_kind = if is_static {
MethodKind::Static
} else if is_virtual {
MethodKind::Virtual {
pure_virtual: cur.method_is_pure_virtual(),
}
} else {
MethodKind::Normal
};
let method =
Method::new(method_kind, signature, is_const);
ci.methods.push(method);
}
_ => unreachable!("How can we see this here?"),
}
}
CXCursor_NonTypeTemplateParameter => {
ci.has_non_type_template_params = true;
}
CXCursor_VarDecl => {
let linkage = cur.linkage();
if linkage != CXLinkage_External &&
linkage != CXLinkage_UniqueExternal
{
return CXChildVisit_Continue;
}
let visibility = cur.visibility();
if visibility != CXVisibility_Default {
return CXChildVisit_Continue;
}
if let Ok(item) = Item::parse(cur, Some(potential_id), ctx)
{
ci.inner_vars.push(item.as_var_id_unchecked());
}
}
// Intentionally not handled
CXCursor_CXXAccessSpecifier |
CXCursor_CXXFinalAttr |
CXCursor_FunctionTemplate |
CXCursor_ConversionFunction => {}
_ => {
warn!(
"unhandled comp member `{}` (kind {:?}) in `{}` ({})",
cur.spelling(),
clang::kind_to_str(cur.kind()),
cursor.spelling(),
cur.location()
);
}
}
CXChildVisit_Continue
});
if let Some((ty, _, public, offset)) = maybe_anonymous_struct_field {
let field =
RawField::new(None, ty, None, None, None, public, offset);
ci.fields.append_raw_field(field);
}
Ok(ci)
}
fn kind_from_cursor(
cursor: &clang::Cursor,
) -> Result<CompKind, ParseError> {
use clang_sys::*;
Ok(match cursor.kind() {
CXCursor_UnionDecl => CompKind::Union,
CXCursor_ClassDecl | CXCursor_StructDecl => CompKind::Struct,
CXCursor_CXXBaseSpecifier |
CXCursor_ClassTemplatePartialSpecialization |
CXCursor_ClassTemplate => match cursor.template_kind() {
CXCursor_UnionDecl => CompKind::Union,
_ => CompKind::Struct,
},
_ => {
warn!("Unknown kind for comp type: {:?}", cursor);
return Err(ParseError::Continue);
}
})
}
/// Get the set of types that were declared within this compound type
/// (e.g. nested class definitions).
pub(crate) fn inner_types(&self) -> &[TypeId] {
&self.inner_types
}
/// Get the set of static variables declared within this compound type.
pub(crate) fn inner_vars(&self) -> &[VarId] {
&self.inner_vars
}
/// Have we found a field with an opaque type that could potentially mess up
/// the layout of this compound type?
pub(crate) fn found_unknown_attr(&self) -> bool {
self.found_unknown_attr
}
/// Is this compound type packed?
pub(crate) fn is_packed(
&self,
ctx: &BindgenContext,
layout: Option<&Layout>,
) -> bool {
if self.packed_attr {
return true;
}
// Even though `libclang` doesn't expose `#pragma packed(...)`, we can
// detect it through its effects.
if let Some(parent_layout) = layout {
let mut packed = false;
self.each_known_field_layout(ctx, |layout| {
packed = packed || layout.align > parent_layout.align;
});
if packed {
info!("Found a struct that was defined within `#pragma packed(...)`");
return true;
}
if self.has_own_virtual_method && parent_layout.align == 1 {
return true;
}
}
false
}
/// Return true if a compound type is "naturally packed". This means we can exclude the
/// "packed" attribute without changing the layout.
/// This is useful for types that need an "align(N)" attribute since rustc won't compile
/// structs that have both of those attributes.
pub(crate) fn already_packed(&self, ctx: &BindgenContext) -> Option<bool> {
let mut total_size: usize = 0;
for field in self.fields().iter() {
let layout = field.layout(ctx)?;
if layout.align != 0 && total_size % layout.align != 0 {
return Some(false);
}
total_size += layout.size;
}
Some(true)
}
/// Returns true if compound type has been forward declared
pub(crate) fn is_forward_declaration(&self) -> bool {
self.is_forward_declaration
}
/// Compute this compound structure's bitfield allocation units.
pub(crate) fn compute_bitfield_units(
&mut self,
ctx: &BindgenContext,
layout: Option<&Layout>,
) {
let packed = self.is_packed(ctx, layout);
self.fields.compute_bitfield_units(ctx, packed)
}
/// Assign for each anonymous field a generated name.
pub(crate) fn deanonymize_fields(&mut self, ctx: &BindgenContext) {
self.fields.deanonymize_fields(ctx, &self.methods);
}
/// Returns whether the current union can be represented as a Rust `union`
///
/// Requirements:
/// 1. Current RustTarget allows for `untagged_union`
/// 2. Each field can derive `Copy` or we use ManuallyDrop.
/// 3. It's not zero-sized.
///
/// Second boolean returns whether all fields can be copied (and thus
/// ManuallyDrop is not needed).
pub(crate) fn is_rust_union(
&self,
ctx: &BindgenContext,
layout: Option<&Layout>,
name: &str,
) -> (bool, bool) {
if !self.is_union() {
return (false, false);
}
if !ctx.options().untagged_union {
return (false, false);
}
if self.is_forward_declaration() {
return (false, false);
}
let union_style = if ctx.options().bindgen_wrapper_union.matches(name) {
NonCopyUnionStyle::BindgenWrapper
} else if ctx.options().manually_drop_union.matches(name) {
NonCopyUnionStyle::ManuallyDrop
} else {
ctx.options().default_non_copy_union_style
};
let all_can_copy = self.fields().iter().all(|f| match *f {
Field::DataMember(ref field_data) => {
field_data.ty().can_derive_copy(ctx)
}
Field::Bitfields(_) => true,
});
if !all_can_copy && union_style == NonCopyUnionStyle::BindgenWrapper {
return (false, false);
}
if layout.map_or(false, |l| l.size == 0) {
return (false, false);
}
(true, all_can_copy)
}
}
impl DotAttributes for CompInfo {
fn dot_attributes<W>(
&self,
ctx: &BindgenContext,
out: &mut W,
) -> io::Result<()>
where
W: io::Write,
{
writeln!(out, "<tr><td>CompKind</td><td>{:?}</td></tr>", self.kind)?;
if self.has_own_virtual_method {
writeln!(out, "<tr><td>has_vtable</td><td>true</td></tr>")?;
}
if self.has_destructor {
writeln!(out, "<tr><td>has_destructor</td><td>true</td></tr>")?;
}
if self.has_nonempty_base {
writeln!(out, "<tr><td>has_nonempty_base</td><td>true</td></tr>")?;
}
if self.has_non_type_template_params {
writeln!(
out,
"<tr><td>has_non_type_template_params</td><td>true</td></tr>"
)?;
}
if self.packed_attr {
writeln!(out, "<tr><td>packed_attr</td><td>true</td></tr>")?;
}
if self.is_forward_declaration {
writeln!(
out,
"<tr><td>is_forward_declaration</td><td>true</td></tr>"
)?;
}
if !self.fields().is_empty() {
writeln!(out, r#"<tr><td>fields</td><td><table border="0">"#)?;
for field in self.fields() {
field.dot_attributes(ctx, out)?;
}
writeln!(out, "</table></td></tr>")?;
}
Ok(())
}
}
impl IsOpaque for CompInfo {
type Extra = Option<Layout>;
fn is_opaque(&self, ctx: &BindgenContext, layout: &Option<Layout>) -> bool {
if self.has_non_type_template_params ||
self.has_unevaluable_bit_field_width
{
return true;
}
// When we do not have the layout for a bitfield's type (for example, it
// is a type parameter), then we can't compute bitfield units. We are
// left with no choice but to make the whole struct opaque, or else we
// might generate structs with incorrect sizes and alignments.
if let CompFields::Error = self.fields {
return true;
}
// Bitfields with a width that is larger than their unit's width have
// some strange things going on, and the best we can do is make the
// whole struct opaque.
if self.fields().iter().any(|f| match *f {
Field::DataMember(_) => false,
Field::Bitfields(ref unit) => unit.bitfields().iter().any(|bf| {
let bitfield_layout = ctx
.resolve_type(bf.ty())
.layout(ctx)
.expect("Bitfield without layout? Gah!");
bf.width() / 8 > bitfield_layout.size as u32
}),
}) {
return true;
}
if !ctx.options().rust_features().repr_packed_n {
// If we don't have `#[repr(packed(N)]`, the best we can
// do is make this struct opaque.
//
// See https://github.com/rust-lang/rust-bindgen/issues/537 and
// https://github.com/rust-lang/rust/issues/33158
if self.is_packed(ctx, layout.as_ref()) &&
layout.map_or(false, |l| l.align > 1)
{
warn!("Found a type that is both packed and aligned to greater than \
1; Rust before version 1.33 doesn't have `#[repr(packed(N))]`, so we \
are treating it as opaque. You may wish to set bindgen's rust target \
version to 1.33 or later to enable `#[repr(packed(N))]` support.");
return true;
}
}
false
}
}
impl TemplateParameters for CompInfo {
fn self_template_params(&self, _ctx: &BindgenContext) -> Vec<TypeId> {
self.template_params.clone()
}
}
impl Trace for CompInfo {
type Extra = Item;
fn trace<T>(&self, context: &BindgenContext, tracer: &mut T, item: &Item)
where
T: Tracer,
{
for p in item.all_template_params(context) {
tracer.visit_kind(p.into(), EdgeKind::TemplateParameterDefinition);
}
for ty in self.inner_types() {
tracer.visit_kind(ty.into(), EdgeKind::InnerType);
}
for &var in self.inner_vars() {
tracer.visit_kind(var.into(), EdgeKind::InnerVar);
}
for method in self.methods() {
tracer.visit_kind(method.signature.into(), EdgeKind::Method);
}
if let Some((_kind, signature)) = self.destructor() {
tracer.visit_kind(signature.into(), EdgeKind::Destructor);
}
for ctor in self.constructors() {
tracer.visit_kind(ctor.into(), EdgeKind::Constructor);
}
// Base members and fields are not generated for opaque types (but all
// of the above things are) so stop here.
if item.is_opaque(context, &()) {
return;
}
for base in self.base_members() {
tracer.visit_kind(base.ty.into(), EdgeKind::BaseMember);
}
self.fields.trace(context, tracer, &());
}
}