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use std::num::NonZeroU32;
use crate::front::wgsl::parse::ast;
use crate::{Handle, Span};
use crate::front::wgsl::error::Error;
use crate::front::wgsl::lower::{ExpressionContext, Lowerer};
/// A cooked form of `ast::ConstructorType` that uses Naga types whenever
/// possible.
enum Constructor<T> {
/// A vector construction whose component type is inferred from the
/// argument: `vec3(1.0)`.
PartialVector { size: crate::VectorSize },
/// A matrix construction whose component type is inferred from the
/// argument: `mat2x2(1,2,3,4)`.
PartialMatrix {
columns: crate::VectorSize,
rows: crate::VectorSize,
},
/// An array whose component type and size are inferred from the arguments:
/// `array(3,4,5)`.
PartialArray,
/// A known Naga type.
///
/// When we match on this type, we need to see the `TypeInner` here, but at
/// the point that we build this value we'll still need mutable access to
/// the module later. To avoid borrowing from the module, the type parameter
/// `T` is `Handle<Type>` initially. Then we use `borrow_inner` to produce a
/// version holding a tuple `(Handle<Type>, &TypeInner)`.
Type(T),
}
impl Constructor<Handle<crate::Type>> {
/// Return an equivalent `Constructor` value that includes borrowed
/// `TypeInner` values alongside any type handles.
///
/// The returned form is more convenient to match on, since the patterns
/// can actually see what the handle refers to.
fn borrow_inner(
self,
module: &crate::Module,
) -> Constructor<(Handle<crate::Type>, &crate::TypeInner)> {
match self {
Constructor::PartialVector { size } => Constructor::PartialVector { size },
Constructor::PartialMatrix { columns, rows } => {
Constructor::PartialMatrix { columns, rows }
}
Constructor::PartialArray => Constructor::PartialArray,
Constructor::Type(handle) => Constructor::Type((handle, &module.types[handle].inner)),
}
}
}
impl Constructor<(Handle<crate::Type>, &crate::TypeInner)> {
fn to_error_string(&self, ctx: &ExpressionContext) -> String {
match *self {
Self::PartialVector { size } => {
format!("vec{}<?>", size as u32,)
}
Self::PartialMatrix { columns, rows } => {
format!("mat{}x{}<?>", columns as u32, rows as u32,)
}
Self::PartialArray => "array<?, ?>".to_string(),
Self::Type((handle, _inner)) => handle.to_wgsl(&ctx.module.to_ctx()),
}
}
}
enum Components<'a> {
None,
One {
component: Handle<crate::Expression>,
span: Span,
ty_inner: &'a crate::TypeInner,
},
Many {
components: Vec<Handle<crate::Expression>>,
spans: Vec<Span>,
},
}
impl Components<'_> {
fn into_components_vec(self) -> Vec<Handle<crate::Expression>> {
match self {
Self::None => vec![],
Self::One { component, .. } => vec![component],
Self::Many { components, .. } => components,
}
}
}
impl<'source, 'temp> Lowerer<'source, 'temp> {
/// Generate Naga IR for a type constructor expression.
///
/// The `constructor` value represents the head of the constructor
/// expression, which is at least a hint of which type is being built; if
/// it's one of the `Partial` variants, we need to consider the argument
/// types as well.
///
/// This is used for [`Construct`] expressions, but also for [`Call`]
/// expressions, once we've determined that the "callable" (in WGSL spec
/// terms) is actually a type.
///
/// [`Construct`]: ast::Expression::Construct
/// [`Call`]: ast::Expression::Call
pub fn construct(
&mut self,
span: Span,
constructor: &ast::ConstructorType<'source>,
ty_span: Span,
components: &[Handle<ast::Expression<'source>>],
ctx: &mut ExpressionContext<'source, '_, '_>,
) -> Result<Handle<crate::Expression>, Error<'source>> {
use crate::proc::TypeResolution as Tr;
let constructor_h = self.constructor(constructor, ctx)?;
let components = match *components {
[] => Components::None,
[component] => {
let span = ctx.ast_expressions.get_span(component);
let component = self.expression_for_abstract(component, ctx)?;
let ty_inner = super::resolve_inner!(ctx, component);
Components::One {
component,
span,
ty_inner,
}
}
ref ast_components @ [_, _, ..] => {
let components = ast_components
.iter()
.map(|&expr| self.expression_for_abstract(expr, ctx))
.collect::<Result<_, _>>()?;
let spans = ast_components
.iter()
.map(|&expr| ctx.ast_expressions.get_span(expr))
.collect();
for &component in &components {
ctx.grow_types(component)?;
}
Components::Many { components, spans }
}
};
// Even though we computed `constructor` above, wait until now to borrow
// a reference to the `TypeInner`, so that the component-handling code
// above can have mutable access to the type arena.
let constructor = constructor_h.borrow_inner(ctx.module);
let expr;
match (components, constructor) {
// Empty constructor
(Components::None, dst_ty) => match dst_ty {
Constructor::Type((result_ty, _)) => {
return ctx.append_expression(crate::Expression::ZeroValue(result_ty), span)
}
Constructor::PartialVector { .. }
| Constructor::PartialMatrix { .. }
| Constructor::PartialArray => {
// We have no arguments from which to infer the result type, so
// partial constructors aren't acceptable here.
return Err(Error::TypeNotInferable(ty_span));
}
},
// Scalar constructor & conversion (scalar -> scalar)
(
Components::One {
component,
ty_inner: &crate::TypeInner::Scalar { .. },
..
},
Constructor::Type((_, &crate::TypeInner::Scalar(scalar))),
) => {
expr = crate::Expression::As {
expr: component,
kind: scalar.kind,
convert: Some(scalar.width),
};
}
// Vector conversion (vector -> vector)
(
Components::One {
component,
ty_inner: &crate::TypeInner::Vector { size: src_size, .. },
..
},
Constructor::Type((
_,
&crate::TypeInner::Vector {
size: dst_size,
scalar: dst_scalar,
},
)),
) if dst_size == src_size => {
expr = crate::Expression::As {
expr: component,
kind: dst_scalar.kind,
convert: Some(dst_scalar.width),
};
}
// Vector conversion (vector -> vector) - partial
(
Components::One {
component,
ty_inner: &crate::TypeInner::Vector { size: src_size, .. },
..
},
Constructor::PartialVector { size: dst_size },
) if dst_size == src_size => {
// This is a trivial conversion: the sizes match, and a Partial
// constructor doesn't specify a scalar type, so nothing can
// possibly happen.
return Ok(component);
}
// Matrix conversion (matrix -> matrix)
(
Components::One {
component,
ty_inner:
&crate::TypeInner::Matrix {
columns: src_columns,
rows: src_rows,
..
},
..
},
Constructor::Type((
_,
&crate::TypeInner::Matrix {
columns: dst_columns,
rows: dst_rows,
scalar: dst_scalar,
},
)),
) if dst_columns == src_columns && dst_rows == src_rows => {
expr = crate::Expression::As {
expr: component,
kind: dst_scalar.kind,
convert: Some(dst_scalar.width),
};
}
// Matrix conversion (matrix -> matrix) - partial
(
Components::One {
component,
ty_inner:
&crate::TypeInner::Matrix {
columns: src_columns,
rows: src_rows,
..
},
..
},
Constructor::PartialMatrix {
columns: dst_columns,
rows: dst_rows,
},
) if dst_columns == src_columns && dst_rows == src_rows => {
// This is a trivial conversion: the sizes match, and a Partial
// constructor doesn't specify a scalar type, so nothing can
// possibly happen.
return Ok(component);
}
// Vector constructor (splat) - infer type
(
Components::One {
component,
ty_inner: &crate::TypeInner::Scalar { .. },
..
},
Constructor::PartialVector { size },
) => {
expr = crate::Expression::Splat {
size,
value: component,
};
}
// Vector constructor (splat)
(
Components::One {
mut component,
ty_inner: &crate::TypeInner::Scalar(_),
..
},
Constructor::Type((_, &crate::TypeInner::Vector { size, scalar })),
) => {
ctx.convert_slice_to_common_leaf_scalar(
std::slice::from_mut(&mut component),
scalar,
)?;
expr = crate::Expression::Splat {
size,
value: component,
};
}
// Vector constructor (by elements), partial
(
Components::Many {
mut components,
spans,
},
Constructor::PartialVector { size },
) => {
let consensus_scalar =
ctx.automatic_conversion_consensus(&components)
.map_err(|index| {
Error::InvalidConstructorComponentType(spans[index], index as i32)
})?;
ctx.convert_slice_to_common_leaf_scalar(&mut components, consensus_scalar)?;
let inner = consensus_scalar.to_inner_vector(size);
let ty = ctx.ensure_type_exists(inner);
expr = crate::Expression::Compose { ty, components };
}
// Vector constructor (by elements), full type given
(
Components::Many { mut components, .. },
Constructor::Type((ty, &crate::TypeInner::Vector { scalar, .. })),
) => {
ctx.try_automatic_conversions_for_vector(&mut components, scalar, ty_span)?;
expr = crate::Expression::Compose { ty, components };
}
// Matrix constructor (by elements), partial
(
Components::Many {
mut components,
spans,
},
Constructor::PartialMatrix { columns, rows },
) if components.len() == columns as usize * rows as usize => {
let consensus_scalar =
ctx.automatic_conversion_consensus(&components)
.map_err(|index| {
Error::InvalidConstructorComponentType(spans[index], index as i32)
})?;
// We actually only accept floating-point elements.
let consensus_scalar = consensus_scalar
.automatic_conversion_combine(crate::Scalar::ABSTRACT_FLOAT)
.unwrap_or(consensus_scalar);
ctx.convert_slice_to_common_leaf_scalar(&mut components, consensus_scalar)?;
let vec_ty = ctx.ensure_type_exists(consensus_scalar.to_inner_vector(rows));
let components = components
.chunks(rows as usize)
.map(|vec_components| {
ctx.append_expression(
crate::Expression::Compose {
ty: vec_ty,
components: Vec::from(vec_components),
},
Default::default(),
)
})
.collect::<Result<Vec<_>, _>>()?;
let ty = ctx.ensure_type_exists(crate::TypeInner::Matrix {
columns,
rows,
scalar: consensus_scalar,
});
expr = crate::Expression::Compose { ty, components };
}
// Matrix constructor (by elements), type given
(
Components::Many { mut components, .. },
Constructor::Type((
_,
&crate::TypeInner::Matrix {
columns,
rows,
scalar,
},
)),
) if components.len() == columns as usize * rows as usize => {
let element = Tr::Value(crate::TypeInner::Scalar(scalar));
ctx.try_automatic_conversions_slice(&mut components, &element, ty_span)?;
let vec_ty = ctx.ensure_type_exists(scalar.to_inner_vector(rows));
let components = components
.chunks(rows as usize)
.map(|vec_components| {
ctx.append_expression(
crate::Expression::Compose {
ty: vec_ty,
components: Vec::from(vec_components),
},
Default::default(),
)
})
.collect::<Result<Vec<_>, _>>()?;
let ty = ctx.ensure_type_exists(crate::TypeInner::Matrix {
columns,
rows,
scalar,
});
expr = crate::Expression::Compose { ty, components };
}
// Matrix constructor (by columns), partial
(
Components::Many {
mut components,
spans,
},
Constructor::PartialMatrix { columns, rows },
) => {
let consensus_scalar =
ctx.automatic_conversion_consensus(&components)
.map_err(|index| {
Error::InvalidConstructorComponentType(spans[index], index as i32)
})?;
ctx.convert_slice_to_common_leaf_scalar(&mut components, consensus_scalar)?;
let ty = ctx.ensure_type_exists(crate::TypeInner::Matrix {
columns,
rows,
scalar: consensus_scalar,
});
expr = crate::Expression::Compose { ty, components };
}
// Matrix constructor (by columns), type given
(
Components::Many { mut components, .. },
Constructor::Type((
ty,
&crate::TypeInner::Matrix {
columns: _,
rows,
scalar,
},
)),
) => {
let component_ty = crate::TypeInner::Vector { size: rows, scalar };
ctx.try_automatic_conversions_slice(
&mut components,
&Tr::Value(component_ty),
ty_span,
)?;
expr = crate::Expression::Compose { ty, components };
}
// Array constructor - infer type
(components, Constructor::PartialArray) => {
let mut components = components.into_components_vec();
if let Ok(consensus_scalar) = ctx.automatic_conversion_consensus(&components) {
// Note that this will *not* necessarily convert all the
// components to the same type! The `automatic_conversion_consensus`
// method only considers the parameters' leaf scalar
// types; the parameters themselves could be any mix of
// vectors, matrices, and scalars.
//
// But *if* it is possible for this array construction
// expression to be well-typed at all, then all the
// parameters must have the same type constructors (vec,
// matrix, scalar) applied to their leaf scalars, so
// reconciling their scalars is always the right thing to
// do. And if this array construction is not well-typed,
// these conversions will not make it so, and we can let
// validation catch the error.
ctx.convert_slice_to_common_leaf_scalar(&mut components, consensus_scalar)?;
} else {
// There's no consensus scalar. Emit the `Compose`
// expression anyway, and let validation catch the problem.
}
let base = ctx.register_type(components[0])?;
let inner = crate::TypeInner::Array {
base,
size: crate::ArraySize::Constant(
NonZeroU32::new(u32::try_from(components.len()).unwrap()).unwrap(),
),
stride: {
self.layouter.update(ctx.module.to_ctx()).unwrap();
self.layouter[base].to_stride()
},
};
let ty = ctx.ensure_type_exists(inner);
expr = crate::Expression::Compose { ty, components };
}
// Array constructor, explicit type
(components, Constructor::Type((ty, &crate::TypeInner::Array { base, .. }))) => {
let mut components = components.into_components_vec();
ctx.try_automatic_conversions_slice(&mut components, &Tr::Handle(base), ty_span)?;
expr = crate::Expression::Compose { ty, components };
}
// Struct constructor
(
components,
Constructor::Type((ty, &crate::TypeInner::Struct { ref members, .. })),
) => {
let mut components = components.into_components_vec();
let struct_ty_span = ctx.module.types.get_span(ty);
// Make a vector of the members' type handles in advance, to
// avoid borrowing `members` from `ctx` while we generate
// new code.
let members: Vec<Handle<crate::Type>> = members.iter().map(|m| m.ty).collect();
for (component, &ty) in components.iter_mut().zip(&members) {
*component =
ctx.try_automatic_conversions(*component, &Tr::Handle(ty), struct_ty_span)?;
}
expr = crate::Expression::Compose { ty, components };
}
// ERRORS
// Bad conversion (type cast)
(Components::One { span, ty_inner, .. }, constructor) => {
let from_type = ty_inner.to_wgsl(&ctx.module.to_ctx()).into();
return Err(Error::BadTypeCast {
span,
from_type,
to_type: constructor.to_error_string(ctx).into(),
});
}
// Too many parameters for scalar constructor
(
Components::Many { spans, .. },
Constructor::Type((_, &crate::TypeInner::Scalar { .. })),
) => {
let span = spans[1].until(spans.last().unwrap());
return Err(Error::UnexpectedComponents(span));
}
// Other types can't be constructed
_ => return Err(Error::TypeNotConstructible(ty_span)),
}
let expr = ctx.append_expression(expr, span)?;
Ok(expr)
}
/// Build a [`Constructor`] for a WGSL construction expression.
///
/// If `constructor` conveys enough information to determine which Naga [`Type`]
/// we're actually building (i.e., it's not a partial constructor), then
/// ensure the `Type` exists in [`ctx.module`], and return
/// [`Constructor::Type`].
///
/// Otherwise, return the [`Constructor`] partial variant corresponding to
/// `constructor`.
///
/// [`Type`]: crate::Type
/// [`ctx.module`]: ExpressionContext::module
fn constructor<'out>(
&mut self,
constructor: &ast::ConstructorType<'source>,
ctx: &mut ExpressionContext<'source, '_, 'out>,
) -> Result<Constructor<Handle<crate::Type>>, Error<'source>> {
let handle = match *constructor {
ast::ConstructorType::Scalar(scalar) => {
let ty = ctx.ensure_type_exists(scalar.to_inner_scalar());
Constructor::Type(ty)
}
ast::ConstructorType::PartialVector { size } => Constructor::PartialVector { size },
ast::ConstructorType::Vector { size, ty, ty_span } => {
let ty = self.resolve_ast_type(ty, &mut ctx.as_global())?;
let scalar = match ctx.module.types[ty].inner {
crate::TypeInner::Scalar(sc) => sc,
_ => return Err(Error::UnknownScalarType(ty_span)),
};
let ty = ctx.ensure_type_exists(crate::TypeInner::Vector { size, scalar });
Constructor::Type(ty)
}
ast::ConstructorType::PartialMatrix { columns, rows } => {
Constructor::PartialMatrix { columns, rows }
}
ast::ConstructorType::Matrix {
rows,
columns,
ty,
ty_span,
} => {
let ty = self.resolve_ast_type(ty, &mut ctx.as_global())?;
let scalar = match ctx.module.types[ty].inner {
crate::TypeInner::Scalar(sc) => sc,
_ => return Err(Error::UnknownScalarType(ty_span)),
};
let ty = match scalar.kind {
crate::ScalarKind::Float => ctx.ensure_type_exists(crate::TypeInner::Matrix {
columns,
rows,
scalar,
}),
_ => return Err(Error::BadMatrixScalarKind(ty_span, scalar)),
};
Constructor::Type(ty)
}
ast::ConstructorType::PartialArray => Constructor::PartialArray,
ast::ConstructorType::Array { base, size } => {
let base = self.resolve_ast_type(base, &mut ctx.as_global())?;
let size = self.array_size(size, &mut ctx.as_global())?;
self.layouter.update(ctx.module.to_ctx()).unwrap();
let stride = self.layouter[base].to_stride();
let ty = ctx.ensure_type_exists(crate::TypeInner::Array { base, size, stride });
Constructor::Type(ty)
}
ast::ConstructorType::Type(ty) => Constructor::Type(ty),
};
Ok(handle)
}
}