1 files changed, 393 insertions, 0 deletions
diff --git a/third_party/rust/naga/src/front/glsl/ast.rs b/third_party/rust/naga/src/front/glsl/ast.rs
new file mode 100644
index 0000000000..cbb21f6de9
--- /dev/null
+++ b/third_party/rust/naga/src/front/glsl/ast.rs
@@ -0,0 +1,393 @@
+use std::{borrow::Cow, fmt};
+
+use super::{builtins::MacroCall, context::ExprPos, Span};
+use crate::{
+    AddressSpace, BinaryOperator, Binding, Constant, Expression, Function, GlobalVariable, Handle,
+    Interpolation, Sampling, StorageAccess, Type, UnaryOperator,
+};
+
+#[derive(Debug, Clone, Copy)]
+pub enum GlobalLookupKind {
+    Variable(Handle<GlobalVariable>),
+    Constant(Handle<Constant>, Handle<Type>),
+    BlockSelect(Handle<GlobalVariable>, u32),
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct GlobalLookup {
+    pub kind: GlobalLookupKind,
+    pub entry_arg: Option<usize>,
+    pub mutable: bool,
+}
+
+#[derive(Debug, Clone)]
+pub struct ParameterInfo {
+    pub qualifier: ParameterQualifier,
+    /// Whether the parameter should be treated as a depth image instead of a
+    /// sampled image.
+    pub depth: bool,
+}
+
+/// How the function is implemented
+#[derive(Clone, Copy)]
+pub enum FunctionKind {
+    /// The function is user defined
+    Call(Handle<Function>),
+    /// The function is a builtin
+    Macro(MacroCall),
+}
+
+impl fmt::Debug for FunctionKind {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match *self {
+            Self::Call(_) => write!(f, "Call"),
+            Self::Macro(_) => write!(f, "Macro"),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Overload {
+    /// Normalized function parameters, modifiers are not applied
+    pub parameters: Vec<Handle<Type>>,
+    pub parameters_info: Vec<ParameterInfo>,
+    /// How the function is implemented
+    pub kind: FunctionKind,
+    /// Whether this function was already defined or is just a prototype
+    pub defined: bool,
+    /// Whether this overload is the one provided by the language or has
+    /// been redeclared by the user (builtins only)
+    pub internal: bool,
+    /// Whether or not this function returns void (nothing)
+    pub void: bool,
+}
+
+bitflags::bitflags! {
+    /// Tracks the variations of the builtin already generated, this is needed because some
+    /// builtins overloads can't be generated unless explicitly used, since they might cause
+    /// unneeded capabilities to be requested
+    #[derive(Default)]
+    pub struct BuiltinVariations: u32 {
+        /// Request the standard overloads
+        const STANDARD = 1 << 0;
+        /// Request overloads that use the double type
+        const DOUBLE = 1 << 1;
+        /// Request overloads that use samplerCubeArray(Shadow)
+        const CUBE_TEXTURES_ARRAY = 1 << 2;
+        /// Request overloads that use sampler2DMSArray
+        const D2_MULTI_TEXTURES_ARRAY = 1 << 3;
+    }
+}
+
+#[derive(Debug, Default)]
+pub struct FunctionDeclaration {
+    pub overloads: Vec<Overload>,
+    /// Tracks the builtin overload variations that were already generated
+    pub variations: BuiltinVariations,
+}
+
+#[derive(Debug)]
+pub struct EntryArg {
+    pub name: Option<String>,
+    pub binding: Binding,
+    pub handle: Handle<GlobalVariable>,
+    pub storage: StorageQualifier,
+}
+
+#[derive(Debug, Clone)]
+pub struct VariableReference {
+    pub expr: Handle<Expression>,
+    /// Wether the variable is of a pointer type (and needs loading) or not
+    pub load: bool,
+    /// Wether the value of the variable can be changed or not
+    pub mutable: bool,
+    pub constant: Option<(Handle<Constant>, Handle<Type>)>,
+    pub entry_arg: Option<usize>,
+}
+
+#[derive(Debug, Clone)]
+pub struct HirExpr {
+    pub kind: HirExprKind,
+    pub meta: Span,
+}
+
+#[derive(Debug, Clone)]
+pub enum HirExprKind {
+    Access {
+        base: Handle<HirExpr>,
+        index: Handle<HirExpr>,
+    },
+    Select {
+        base: Handle<HirExpr>,
+        field: String,
+    },
+    Constant(Handle<Constant>),
+    Binary {
+        left: Handle<HirExpr>,
+        op: BinaryOperator,
+        right: Handle<HirExpr>,
+    },
+    Unary {
+        op: UnaryOperator,
+        expr: Handle<HirExpr>,
+    },
+    Variable(VariableReference),
+    Call(FunctionCall),
+    /// Represents the ternary operator in glsl (`:?`)
+    Conditional {
+        /// The expression that will decide which branch to take, must evaluate to a boolean
+        condition: Handle<HirExpr>,
+        /// The expression that will be evaluated if [`condition`] returns `true`
+        ///
+        /// [`condition`]: Self::Conditional::condition
+        accept: Handle<HirExpr>,
+        /// The expression that will be evaluated if [`condition`] returns `false`
+        ///
+        /// [`condition`]: Self::Conditional::condition
+        reject: Handle<HirExpr>,
+    },
+    Assign {
+        tgt: Handle<HirExpr>,
+        value: Handle<HirExpr>,
+    },
+    /// A prefix/postfix operator like `++`
+    PrePostfix {
+        /// The operation to be performed
+        op: BinaryOperator,
+        /// Whether this is a postfix or a prefix
+        postfix: bool,
+        /// The target expression
+        expr: Handle<HirExpr>,
+    },
+    /// A method call like `what.something(a, b, c)`
+    Method {
+        /// expression the method call applies to (`what` in the example)
+        expr: Handle<HirExpr>,
+        /// the method name (`something` in the example)
+        name: String,
+        /// the arguments to the method (`a`, `b`, and `c` in the example)
+        args: Vec<Handle<HirExpr>>,
+    },
+}
+
+#[derive(Debug, Hash, PartialEq, Eq)]
+pub enum QualifierKey<'a> {
+    String(Cow<'a, str>),
+    /// Used for `std140` and `std430` layout qualifiers
+    Layout,
+    /// Used for image formats
+    Format,
+}
+
+#[derive(Debug)]
+pub enum QualifierValue {
+    None,
+    Uint(u32),
+    Layout(StructLayout),
+    Format(crate::StorageFormat),
+}
+
+#[derive(Debug, Default)]
+pub struct TypeQualifiers<'a> {
+    pub span: Span,
+    pub storage: (StorageQualifier, Span),
+    pub invariant: Option<Span>,
+    pub interpolation: Option<(Interpolation, Span)>,
+    pub precision: Option<(Precision, Span)>,
+    pub sampling: Option<(Sampling, Span)>,
+    /// Memory qualifiers used in the declaration to set the storage access to be used
+    /// in declarations that support it (storage images and buffers)
+    pub storage_access: Option<(StorageAccess, Span)>,
+    pub layout_qualifiers: crate::FastHashMap<QualifierKey<'a>, (QualifierValue, Span)>,
+}
+
+impl<'a> TypeQualifiers<'a> {
+    /// Appends `errors` with errors for all unused qualifiers
+    pub fn unused_errors(&self, errors: &mut Vec<super::Error>) {
+        if let Some(meta) = self.invariant {
+            errors.push(super::Error {
+                kind: super::ErrorKind::SemanticError(
+                    "Invariant qualifier can only be used in in/out variables".into(),
+                ),
+                meta,
+            });
+        }
+
+        if let Some((_, meta)) = self.interpolation {
+            errors.push(super::Error {
+                kind: super::ErrorKind::SemanticError(
+                    "Interpolation qualifiers can only be used in in/out variables".into(),
+                ),
+                meta,
+            });
+        }
+
+        if let Some((_, meta)) = self.sampling {
+            errors.push(super::Error {
+                kind: super::ErrorKind::SemanticError(
+                    "Sampling qualifiers can only be used in in/out variables".into(),
+                ),
+                meta,
+            });
+        }
+
+        if let Some((_, meta)) = self.storage_access {
+            errors.push(super::Error {
+                kind: super::ErrorKind::SemanticError(
+                    "Memory qualifiers can only be used in storage variables".into(),
+                ),
+                meta,
+            });
+        }
+
+        for &(_, meta) in self.layout_qualifiers.values() {
+            errors.push(super::Error {
+                kind: super::ErrorKind::SemanticError("Unexpected qualifier".into()),
+                meta,
+            });
+        }
+    }
+
+    /// Removes the layout qualifier with `name`, if it exists and adds an error if it isn't
+    /// a [`QualifierValue::Uint`]
+    pub fn uint_layout_qualifier(
+        &mut self,
+        name: &'a str,
+        errors: &mut Vec<super::Error>,
+    ) -> Option<u32> {
+        match self
+            .layout_qualifiers
+            .remove(&QualifierKey::String(name.into()))
+        {
+            Some((QualifierValue::Uint(v), _)) => Some(v),
+            Some((_, meta)) => {
+                errors.push(super::Error {
+                    kind: super::ErrorKind::SemanticError("Qualifier expects a uint value".into()),
+                    meta,
+                });
+                // Return a dummy value instead of `None` to differentiate from
+                // the qualifier not existing, since some parts might require the
+                // qualifier to exist and throwing another error that it doesn't
+                // exist would be unhelpful
+                Some(0)
+            }
+            _ => None,
+        }
+    }
+
+    /// Removes the layout qualifier with `name`, if it exists and adds an error if it isn't
+    /// a [`QualifierValue::None`]
+    pub fn none_layout_qualifier(&mut self, name: &'a str, errors: &mut Vec<super::Error>) -> bool {
+        match self
+            .layout_qualifiers
+            .remove(&QualifierKey::String(name.into()))
+        {
+            Some((QualifierValue::None, _)) => true,
+            Some((_, meta)) => {
+                errors.push(super::Error {
+                    kind: super::ErrorKind::SemanticError(
+                        "Qualifier doesn't expect a value".into(),
+                    ),
+                    meta,
+                });
+                // Return a `true` to since the qualifier is defined and adding
+                // another error for it not being defined would be unhelpful
+                true
+            }
+            _ => false,
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub enum FunctionCallKind {
+    TypeConstructor(Handle<Type>),
+    Function(String),
+}
+
+#[derive(Debug, Clone)]
+pub struct FunctionCall {
+    pub kind: FunctionCallKind,
+    pub args: Vec<Handle<HirExpr>>,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum StorageQualifier {
+    AddressSpace(AddressSpace),
+    Input,
+    Output,
+    Const,
+}
+
+impl Default for StorageQualifier {
+    fn default() -> Self {
+        StorageQualifier::AddressSpace(AddressSpace::Function)
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum StructLayout {
+    Std140,
+    Std430,
+}
+
+// TODO: Encode precision hints in the IR
+/// A precision hint used in GLSL declarations.
+///
+/// Precision hints can be used to either speed up shader execution or control
+/// the precision of arithmetic operations.
+///
+/// To use a precision hint simply add it before the type in the declaration.
+/// ```glsl
+/// mediump float a;
+/// ```
+///
+/// The default when no precision is declared is `highp` which means that all
+/// operations operate with the type defined width.
+///
+/// For `mediump` and `lowp` operations follow the spir-v
+/// [`RelaxedPrecision`][RelaxedPrecision] decoration semantics.
+///
+/// [RelaxedPrecision]: https://www.khronos.org/registry/SPIR-V/specs/unified1/SPIRV.html#_a_id_relaxedprecisionsection_a_relaxed_precision
+#[derive(Debug, Clone, PartialEq, Copy)]
+pub enum Precision {
+    /// `lowp` precision
+    Low,
+    /// `mediump` precision
+    Medium,
+    /// `highp` precision
+    High,
+}
+
+#[derive(Debug, Clone, PartialEq, Copy)]
+pub enum ParameterQualifier {
+    In,
+    Out,
+    InOut,
+    Const,
+}
+
+impl ParameterQualifier {
+    /// Returns true if the argument should be passed as a lhs expression
+    pub const fn is_lhs(&self) -> bool {
+        match *self {
+            ParameterQualifier::Out | ParameterQualifier::InOut => true,
+            _ => false,
+        }
+    }
+
+    /// Converts from a parameter qualifier into a [`ExprPos`](ExprPos)
+    pub const fn as_pos(&self) -> ExprPos {
+        match *self {
+            ParameterQualifier::Out | ParameterQualifier::InOut => ExprPos::Lhs,
+            _ => ExprPos::Rhs,
+        }
+    }
+}
+
+/// The GLSL profile used by a shader.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum Profile {
+    /// The `core` profile, default when no profile is specified.
+    Core,
+}