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use alloc::{boxed::Box, vec::Vec};
use directive::enable_extension::ImplementedEnableExtension;
use crate::diagnostic_filter::{
self, DiagnosticFilter, DiagnosticFilterMap, DiagnosticFilterNode, FilterableTriggeringRule,
ShouldConflictOnFullDuplicate, StandardFilterableTriggeringRule,
};
use crate::front::wgsl::error::{DiagnosticAttributeNotSupportedPosition, Error, ExpectedToken};
use crate::front::wgsl::parse::directive::enable_extension::{EnableExtension, EnableExtensions};
use crate::front::wgsl::parse::directive::language_extension::LanguageExtension;
use crate::front::wgsl::parse::directive::DirectiveKind;
use crate::front::wgsl::parse::lexer::{Lexer, Token, TokenSpan};
use crate::front::wgsl::parse::number::Number;
use crate::front::wgsl::Result;
use crate::front::SymbolTable;
use crate::{Arena, FastHashSet, FastIndexSet, Handle, ShaderStage, Span};
pub mod ast;
pub mod conv;
pub mod directive;
pub mod lexer;
pub mod number;
/// State for constructing an AST expression.
///
/// Not to be confused with [`lower::ExpressionContext`], which is for producing
/// Naga IR from the AST we produce here.
///
/// [`lower::ExpressionContext`]: super::lower::ExpressionContext
struct ExpressionContext<'input, 'temp, 'out> {
/// The [`TranslationUnit::expressions`] arena to which we should contribute
/// expressions.
///
/// [`TranslationUnit::expressions`]: ast::TranslationUnit::expressions
expressions: &'out mut Arena<ast::Expression<'input>>,
/// A map from identifiers in scope to the locals/arguments they represent.
///
/// The handles refer to the [`locals`] arena; see that field's
/// documentation for details.
///
/// [`locals`]: ExpressionContext::locals
local_table: &'temp mut SymbolTable<&'input str, Handle<ast::Local>>,
/// Local variable and function argument arena for the function we're building.
///
/// Note that the [`ast::Local`] here is actually a zero-sized type. This
/// `Arena`'s only role is to assign a unique `Handle` to each local
/// identifier, and track its definition's span for use in diagnostics. All
/// the detailed information about locals - names, types, etc. - is kept in
/// the [`LocalDecl`] statements we parsed from their declarations. For
/// arguments, that information is kept in [`arguments`].
///
/// In the AST, when an [`Ident`] expression refers to a local variable or
/// argument, its [`IdentExpr`] holds the referent's `Handle<Local>` in this
/// arena.
///
/// During lowering, [`LocalDecl`] statements add entries to a per-function
/// table that maps `Handle<Local>` values to their Naga representations,
/// accessed via [`StatementContext::local_table`] and
/// [`LocalExpressionContext::local_table`]. This table is then consulted when
/// lowering subsequent [`Ident`] expressions.
///
/// [`LocalDecl`]: ast::StatementKind::LocalDecl
/// [`arguments`]: ast::Function::arguments
/// [`Ident`]: ast::Expression::Ident
/// [`IdentExpr`]: ast::IdentExpr
/// [`StatementContext::local_table`]: super::lower::StatementContext::local_table
/// [`LocalExpressionContext::local_table`]: super::lower::LocalExpressionContext::local_table
locals: &'out mut Arena<ast::Local>,
/// Identifiers used by the current global declaration that have no local definition.
///
/// This becomes the [`GlobalDecl`]'s [`dependencies`] set.
///
/// Note that we don't know at parse time what kind of [`GlobalDecl`] the
/// name refers to. We can't look up names until we've seen the entire
/// translation unit.
///
/// [`GlobalDecl`]: ast::GlobalDecl
/// [`dependencies`]: ast::GlobalDecl::dependencies
unresolved: &'out mut FastIndexSet<ast::Dependency<'input>>,
}
impl<'a> ExpressionContext<'a, '_, '_> {
fn parse_binary_op(
&mut self,
lexer: &mut Lexer<'a>,
classifier: impl Fn(Token<'a>) -> Option<crate::BinaryOperator>,
mut parser: impl FnMut(&mut Lexer<'a>, &mut Self) -> Result<'a, Handle<ast::Expression<'a>>>,
) -> Result<'a, Handle<ast::Expression<'a>>> {
let start = lexer.start_byte_offset();
let mut accumulator = parser(lexer, self)?;
while let Some(op) = classifier(lexer.peek().0) {
let _ = lexer.next();
let left = accumulator;
let right = parser(lexer, self)?;
accumulator = self.expressions.append(
ast::Expression::Binary { op, left, right },
lexer.span_from(start),
);
}
Ok(accumulator)
}
fn declare_local(&mut self, name: ast::Ident<'a>) -> Result<'a, Handle<ast::Local>> {
let handle = self.locals.append(ast::Local, name.span);
if let Some(old) = self.local_table.add(name.name, handle) {
Err(Box::new(Error::Redefinition {
previous: self.locals.get_span(old),
current: name.span,
}))
} else {
Ok(handle)
}
}
}
/// Which grammar rule we are in the midst of parsing.
///
/// This is used for error checking. `Parser` maintains a stack of
/// these and (occasionally) checks that it is being pushed and popped
/// as expected.
#[derive(Copy, Clone, Debug, PartialEq)]
enum Rule {
Attribute,
VariableDecl,
FunctionDecl,
Block,
Statement,
PrimaryExpr,
SingularExpr,
UnaryExpr,
GeneralExpr,
Directive,
GenericExpr,
EnclosedExpr,
LhsExpr,
}
struct ParsedAttribute<T> {
value: Option<T>,
}
impl<T> Default for ParsedAttribute<T> {
fn default() -> Self {
Self { value: None }
}
}
impl<T> ParsedAttribute<T> {
fn set(&mut self, value: T, name_span: Span) -> Result<'static, ()> {
if self.value.is_some() {
return Err(Box::new(Error::RepeatedAttribute(name_span)));
}
self.value = Some(value);
Ok(())
}
}
#[derive(Default)]
struct BindingParser<'a> {
location: ParsedAttribute<Handle<ast::Expression<'a>>>,
built_in: ParsedAttribute<crate::BuiltIn>,
interpolation: ParsedAttribute<crate::Interpolation>,
sampling: ParsedAttribute<crate::Sampling>,
invariant: ParsedAttribute<bool>,
blend_src: ParsedAttribute<Handle<ast::Expression<'a>>>,
per_primitive: ParsedAttribute<()>,
}
impl<'a> BindingParser<'a> {
fn parse(
&mut self,
parser: &mut Parser,
lexer: &mut Lexer<'a>,
name: &'a str,
name_span: Span,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, ()> {
match name {
"location" => {
lexer.expect(Token::Paren('('))?;
self.location
.set(parser.expression(lexer, ctx)?, name_span)?;
lexer.next_if(Token::Separator(','));
lexer.expect(Token::Paren(')'))?;
}
"builtin" => {
lexer.expect(Token::Paren('('))?;
let (raw, span) = lexer.next_ident_with_span()?;
self.built_in.set(
conv::map_built_in(&lexer.enable_extensions, raw, span)?,
name_span,
)?;
lexer.next_if(Token::Separator(','));
lexer.expect(Token::Paren(')'))?;
}
"interpolate" => {
lexer.expect(Token::Paren('('))?;
let (raw, span) = lexer.next_ident_with_span()?;
self.interpolation
.set(conv::map_interpolation(raw, span)?, name_span)?;
if lexer.next_if(Token::Separator(',')) {
let (raw, span) = lexer.next_ident_with_span()?;
self.sampling
.set(conv::map_sampling(raw, span)?, name_span)?;
}
lexer.next_if(Token::Separator(','));
lexer.expect(Token::Paren(')'))?;
}
"invariant" => {
self.invariant.set(true, name_span)?;
}
"blend_src" => {
lexer.require_enable_extension(
ImplementedEnableExtension::DualSourceBlending,
name_span,
)?;
lexer.expect(Token::Paren('('))?;
self.blend_src
.set(parser.expression(lexer, ctx)?, name_span)?;
lexer.next_if(Token::Separator(','));
lexer.expect(Token::Paren(')'))?;
}
"per_primitive" => {
lexer.require_enable_extension(
ImplementedEnableExtension::WgpuMeshShader,
name_span,
)?;
self.per_primitive.set((), name_span)?;
}
_ => return Err(Box::new(Error::UnknownAttribute(name_span))),
}
Ok(())
}
fn finish(self, span: Span) -> Result<'a, Option<ast::Binding<'a>>> {
match (
self.location.value,
self.built_in.value,
self.interpolation.value,
self.sampling.value,
self.invariant.value.unwrap_or_default(),
self.blend_src.value,
self.per_primitive.value,
) {
(None, None, None, None, false, None, None) => Ok(None),
(Some(location), None, interpolation, sampling, false, blend_src, per_primitive) => {
// Before handing over the completed `Module`, we call
// `apply_default_interpolation` to ensure that the interpolation and
// sampling have been explicitly specified on all vertex shader output and fragment
// shader input user bindings, so leaving them potentially `None` here is fine.
Ok(Some(ast::Binding::Location {
location,
interpolation,
sampling,
blend_src,
per_primitive: per_primitive.is_some(),
}))
}
(None, Some(crate::BuiltIn::Position { .. }), None, None, invariant, None, None) => {
Ok(Some(ast::Binding::BuiltIn(crate::BuiltIn::Position {
invariant,
})))
}
(None, Some(built_in), None, None, false, None, None) => {
Ok(Some(ast::Binding::BuiltIn(built_in)))
}
(_, _, _, _, _, _, _) => Err(Box::new(Error::InconsistentBinding(span))),
}
}
}
/// Configuration for the whole parser run.
pub struct Options {
/// Controls whether the parser should parse doc comments.
pub parse_doc_comments: bool,
/// Capabilities to enable during parsing.
pub capabilities: crate::valid::Capabilities,
}
impl Options {
/// Creates a new default [`Options`].
pub const fn new() -> Self {
Options {
parse_doc_comments: false,
capabilities: crate::valid::Capabilities::all(),
}
}
}
pub struct Parser {
rules: Vec<(Rule, usize)>,
recursion_depth: u32,
}
impl Parser {
pub const fn new() -> Self {
Parser {
rules: Vec::new(),
recursion_depth: 0,
}
}
fn reset(&mut self) {
self.rules.clear();
self.recursion_depth = 0;
}
fn push_rule_span(&mut self, rule: Rule, lexer: &mut Lexer<'_>) {
self.rules.push((rule, lexer.start_byte_offset()));
}
fn pop_rule_span(&mut self, lexer: &Lexer<'_>) -> Span {
let (_, initial) = self.rules.pop().unwrap();
lexer.span_from(initial)
}
fn peek_rule_span(&mut self, lexer: &Lexer<'_>) -> Span {
let &(_, initial) = self.rules.last().unwrap();
lexer.span_from(initial)
}
fn race_rules(&self, rule0: Rule, rule1: Rule) -> Option<Rule> {
Some(
self.rules
.iter()
.rev()
.find(|&x| x.0 == rule0 || x.0 == rule1)?
.0,
)
}
fn track_recursion<'a, F, R>(&mut self, f: F) -> Result<'a, R>
where
F: FnOnce(&mut Self) -> Result<'a, R>,
{
self.recursion_depth += 1;
if self.recursion_depth >= 256 {
return Err(Box::new(Error::Internal("Parser recursion limit exceeded")));
}
let ret = f(self);
self.recursion_depth -= 1;
ret
}
fn switch_value<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, ast::SwitchValue<'a>> {
if lexer.next_if(Token::Word("default")) {
return Ok(ast::SwitchValue::Default);
}
let expr = self.expression(lexer, ctx)?;
Ok(ast::SwitchValue::Expr(expr))
}
/// Expects `name` to be consumed (not in lexer).
fn arguments<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, Vec<Handle<ast::Expression<'a>>>> {
self.push_rule_span(Rule::EnclosedExpr, lexer);
lexer.open_arguments()?;
let mut arguments = Vec::new();
loop {
if !arguments.is_empty() {
if !lexer.next_argument()? {
break;
}
} else if lexer.next_if(Token::Paren(')')) {
break;
}
let arg = self.expression(lexer, ctx)?;
arguments.push(arg);
}
self.pop_rule_span(lexer);
Ok(arguments)
}
fn enclosed_expression<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, Handle<ast::Expression<'a>>> {
self.push_rule_span(Rule::EnclosedExpr, lexer);
let expr = self.expression(lexer, ctx)?;
self.pop_rule_span(lexer);
Ok(expr)
}
fn ident_expr<'a>(
&mut self,
name: &'a str,
name_span: Span,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> ast::IdentExpr<'a> {
match ctx.local_table.lookup(name) {
Some(&local) => ast::IdentExpr::Local(local),
None => {
ctx.unresolved.insert(ast::Dependency {
ident: name,
usage: name_span,
});
ast::IdentExpr::Unresolved(name)
}
}
}
fn primary_expression<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
token: TokenSpan<'a>,
) -> Result<'a, Handle<ast::Expression<'a>>> {
self.push_rule_span(Rule::PrimaryExpr, lexer);
const fn literal_ray_flag<'b>(flag: crate::RayFlag) -> ast::Expression<'b> {
ast::Expression::Literal(ast::Literal::Number(Number::U32(flag.bits())))
}
const fn literal_ray_intersection<'b>(
intersection: crate::RayQueryIntersection,
) -> ast::Expression<'b> {
ast::Expression::Literal(ast::Literal::Number(Number::U32(intersection as u32)))
}
let expr = match token {
(Token::Paren('('), _) => {
let expr = self.enclosed_expression(lexer, ctx)?;
lexer.expect(Token::Paren(')'))?;
self.pop_rule_span(lexer);
return Ok(expr);
}
(Token::Word("true"), _) => ast::Expression::Literal(ast::Literal::Bool(true)),
(Token::Word("false"), _) => ast::Expression::Literal(ast::Literal::Bool(false)),
(Token::Number(res), span) => {
let num = res.map_err(|err| Error::BadNumber(span, err))?;
if let Some(enable_extension) = num.requires_enable_extension() {
lexer.require_enable_extension(enable_extension, span)?;
}
ast::Expression::Literal(ast::Literal::Number(num))
}
(Token::Word("RAY_FLAG_NONE"), _) => literal_ray_flag(crate::RayFlag::empty()),
(Token::Word("RAY_FLAG_FORCE_OPAQUE"), _) => {
literal_ray_flag(crate::RayFlag::FORCE_OPAQUE)
}
(Token::Word("RAY_FLAG_FORCE_NO_OPAQUE"), _) => {
literal_ray_flag(crate::RayFlag::FORCE_NO_OPAQUE)
}
(Token::Word("RAY_FLAG_TERMINATE_ON_FIRST_HIT"), _) => {
literal_ray_flag(crate::RayFlag::TERMINATE_ON_FIRST_HIT)
}
(Token::Word("RAY_FLAG_SKIP_CLOSEST_HIT_SHADER"), _) => {
literal_ray_flag(crate::RayFlag::SKIP_CLOSEST_HIT_SHADER)
}
(Token::Word("RAY_FLAG_CULL_BACK_FACING"), _) => {
literal_ray_flag(crate::RayFlag::CULL_BACK_FACING)
}
(Token::Word("RAY_FLAG_CULL_FRONT_FACING"), _) => {
literal_ray_flag(crate::RayFlag::CULL_FRONT_FACING)
}
(Token::Word("RAY_FLAG_CULL_OPAQUE"), _) => {
literal_ray_flag(crate::RayFlag::CULL_OPAQUE)
}
(Token::Word("RAY_FLAG_CULL_NO_OPAQUE"), _) => {
literal_ray_flag(crate::RayFlag::CULL_NO_OPAQUE)
}
(Token::Word("RAY_FLAG_SKIP_TRIANGLES"), _) => {
literal_ray_flag(crate::RayFlag::SKIP_TRIANGLES)
}
(Token::Word("RAY_FLAG_SKIP_AABBS"), _) => literal_ray_flag(crate::RayFlag::SKIP_AABBS),
(Token::Word("RAY_QUERY_INTERSECTION_NONE"), _) => {
literal_ray_intersection(crate::RayQueryIntersection::None)
}
(Token::Word("RAY_QUERY_INTERSECTION_TRIANGLE"), _) => {
literal_ray_intersection(crate::RayQueryIntersection::Triangle)
}
(Token::Word("RAY_QUERY_INTERSECTION_GENERATED"), _) => {
literal_ray_intersection(crate::RayQueryIntersection::Generated)
}
(Token::Word("RAY_QUERY_INTERSECTION_AABB"), _) => {
literal_ray_intersection(crate::RayQueryIntersection::Aabb)
}
(Token::Word(word), span) => {
let ident = self.template_elaborated_ident(word, span, lexer, ctx)?;
if let Token::Paren('(') = lexer.peek().0 {
let arguments = self.arguments(lexer, ctx)?;
ast::Expression::Call(ast::CallPhrase {
function: ident,
arguments,
})
} else {
ast::Expression::Ident(ident)
}
}
other => {
return Err(Box::new(Error::Unexpected(
other.1,
ExpectedToken::PrimaryExpression,
)))
}
};
self.pop_rule_span(lexer);
let span = lexer.span_with_start(token.1);
let expr = ctx.expressions.append(expr, span);
Ok(expr)
}
fn component_or_swizzle_specifier<'a>(
&mut self,
expr_start: Span,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
expr: Handle<ast::Expression<'a>>,
) -> Result<'a, Handle<ast::Expression<'a>>> {
let mut expr = expr;
loop {
let expression = match lexer.peek().0 {
Token::Separator('.') => {
let _ = lexer.next();
let field = lexer.next_ident()?;
ast::Expression::Member { base: expr, field }
}
Token::Paren('[') => {
let _ = lexer.next();
let index = self.enclosed_expression(lexer, ctx)?;
lexer.expect(Token::Paren(']'))?;
ast::Expression::Index { base: expr, index }
}
_ => break,
};
let span = lexer.span_with_start(expr_start);
expr = ctx.expressions.append(expression, span);
}
Ok(expr)
}
/// Parse a `unary_expression`.
fn unary_expression<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, Handle<ast::Expression<'a>>> {
self.push_rule_span(Rule::UnaryExpr, lexer);
enum UnaryOp {
Negate,
LogicalNot,
BitwiseNot,
Deref,
AddrOf,
}
let mut ops = Vec::new();
let mut expr;
loop {
match lexer.next() {
(Token::Operation('-'), span) => {
ops.push((UnaryOp::Negate, span));
}
(Token::Operation('!'), span) => {
ops.push((UnaryOp::LogicalNot, span));
}
(Token::Operation('~'), span) => {
ops.push((UnaryOp::BitwiseNot, span));
}
(Token::Operation('*'), span) => {
ops.push((UnaryOp::Deref, span));
}
(Token::Operation('&'), span) => {
ops.push((UnaryOp::AddrOf, span));
}
token => {
expr = self.singular_expression(lexer, ctx, token)?;
break;
}
};
}
for (op, span) in ops.into_iter().rev() {
let e = match op {
UnaryOp::Negate => ast::Expression::Unary {
op: crate::UnaryOperator::Negate,
expr,
},
UnaryOp::LogicalNot => ast::Expression::Unary {
op: crate::UnaryOperator::LogicalNot,
expr,
},
UnaryOp::BitwiseNot => ast::Expression::Unary {
op: crate::UnaryOperator::BitwiseNot,
expr,
},
UnaryOp::Deref => ast::Expression::Deref(expr),
UnaryOp::AddrOf => ast::Expression::AddrOf(expr),
};
let span = lexer.span_with_start(span);
expr = ctx.expressions.append(e, span);
}
self.pop_rule_span(lexer);
Ok(expr)
}
/// Parse a `lhs_expression`.
///
/// LHS expressions only support the `&` and `*` operators and
/// the `[]` and `.` postfix selectors.
fn lhs_expression<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
token: Option<TokenSpan<'a>>,
expected_token: ExpectedToken<'a>,
) -> Result<'a, Handle<ast::Expression<'a>>> {
self.track_recursion(|this| {
this.push_rule_span(Rule::LhsExpr, lexer);
let token = token.unwrap_or_else(|| lexer.next());
let expr = match token {
(Token::Operation('*'), _) => {
let expr =
this.lhs_expression(lexer, ctx, None, ExpectedToken::LhsExpression)?;
let expr = ast::Expression::Deref(expr);
let span = this.peek_rule_span(lexer);
ctx.expressions.append(expr, span)
}
(Token::Operation('&'), _) => {
let expr =
this.lhs_expression(lexer, ctx, None, ExpectedToken::LhsExpression)?;
let expr = ast::Expression::AddrOf(expr);
let span = this.peek_rule_span(lexer);
ctx.expressions.append(expr, span)
}
(Token::Paren('('), span) => {
let expr =
this.lhs_expression(lexer, ctx, None, ExpectedToken::LhsExpression)?;
lexer.expect(Token::Paren(')'))?;
this.component_or_swizzle_specifier(span, lexer, ctx, expr)?
}
(Token::Word(word), span) => {
let ident = this.ident_expr(word, span, ctx);
let ident = ast::TemplateElaboratedIdent {
ident,
ident_span: span,
template_list: Vec::new(),
template_list_span: Span::UNDEFINED,
};
let ident = ctx.expressions.append(ast::Expression::Ident(ident), span);
this.component_or_swizzle_specifier(span, lexer, ctx, ident)?
}
(_, span) => {
return Err(Box::new(Error::Unexpected(span, expected_token)));
}
};
this.pop_rule_span(lexer);
Ok(expr)
})
}
/// Parse a `singular_expression`.
fn singular_expression<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
token: TokenSpan<'a>,
) -> Result<'a, Handle<ast::Expression<'a>>> {
self.push_rule_span(Rule::SingularExpr, lexer);
let primary_expr = self.primary_expression(lexer, ctx, token)?;
let singular_expr =
self.component_or_swizzle_specifier(token.1, lexer, ctx, primary_expr)?;
self.pop_rule_span(lexer);
Ok(singular_expr)
}
fn equality_expression<'a>(
&mut self,
lexer: &mut Lexer<'a>,
context: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, Handle<ast::Expression<'a>>> {
// equality_expression
context.parse_binary_op(
lexer,
|token| match token {
Token::LogicalOperation('=') => Some(crate::BinaryOperator::Equal),
Token::LogicalOperation('!') => Some(crate::BinaryOperator::NotEqual),
_ => None,
},
// relational_expression
|lexer, context| {
let enclosing = self.race_rules(Rule::GenericExpr, Rule::EnclosedExpr);
context.parse_binary_op(
lexer,
match enclosing {
Some(Rule::GenericExpr) => |token| match token {
Token::LogicalOperation('<') => Some(crate::BinaryOperator::LessEqual),
_ => None,
},
_ => |token| match token {
Token::Paren('<') => Some(crate::BinaryOperator::Less),
Token::Paren('>') => Some(crate::BinaryOperator::Greater),
Token::LogicalOperation('<') => Some(crate::BinaryOperator::LessEqual),
Token::LogicalOperation('>') => {
Some(crate::BinaryOperator::GreaterEqual)
}
_ => None,
},
},
// shift_expression
|lexer, context| {
context.parse_binary_op(
lexer,
match enclosing {
Some(Rule::GenericExpr) => |token| match token {
Token::ShiftOperation('<') => {
Some(crate::BinaryOperator::ShiftLeft)
}
_ => None,
},
_ => |token| match token {
Token::ShiftOperation('<') => {
Some(crate::BinaryOperator::ShiftLeft)
}
Token::ShiftOperation('>') => {
Some(crate::BinaryOperator::ShiftRight)
}
_ => None,
},
},
// additive_expression
|lexer, context| {
context.parse_binary_op(
lexer,
|token| match token {
Token::Operation('+') => Some(crate::BinaryOperator::Add),
Token::Operation('-') => {
Some(crate::BinaryOperator::Subtract)
}
_ => None,
},
// multiplicative_expression
|lexer, context| {
context.parse_binary_op(
lexer,
|token| match token {
Token::Operation('*') => {
Some(crate::BinaryOperator::Multiply)
}
Token::Operation('/') => {
Some(crate::BinaryOperator::Divide)
}
Token::Operation('%') => {
Some(crate::BinaryOperator::Modulo)
}
_ => None,
},
|lexer, context| self.unary_expression(lexer, context),
)
},
)
},
)
},
)
},
)
}
fn expression<'a>(
&mut self,
lexer: &mut Lexer<'a>,
context: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, Handle<ast::Expression<'a>>> {
self.push_rule_span(Rule::GeneralExpr, lexer);
// logical_or_expression
let handle = context.parse_binary_op(
lexer,
|token| match token {
Token::LogicalOperation('|') => Some(crate::BinaryOperator::LogicalOr),
_ => None,
},
// logical_and_expression
|lexer, context| {
context.parse_binary_op(
lexer,
|token| match token {
Token::LogicalOperation('&') => Some(crate::BinaryOperator::LogicalAnd),
_ => None,
},
// inclusive_or_expression
|lexer, context| {
context.parse_binary_op(
lexer,
|token| match token {
Token::Operation('|') => Some(crate::BinaryOperator::InclusiveOr),
_ => None,
},
// exclusive_or_expression
|lexer, context| {
context.parse_binary_op(
lexer,
|token| match token {
Token::Operation('^') => {
Some(crate::BinaryOperator::ExclusiveOr)
}
_ => None,
},
// and_expression
|lexer, context| {
context.parse_binary_op(
lexer,
|token| match token {
Token::Operation('&') => {
Some(crate::BinaryOperator::And)
}
_ => None,
},
|lexer, context| {
self.equality_expression(lexer, context)
},
)
},
)
},
)
},
)
},
)?;
self.pop_rule_span(lexer);
Ok(handle)
}
fn optionally_typed_ident<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, (ast::Ident<'a>, Option<ast::TemplateElaboratedIdent<'a>>)> {
let name = lexer.next_ident()?;
let ty = if lexer.next_if(Token::Separator(':')) {
Some(self.type_specifier(lexer, ctx)?)
} else {
None
};
Ok((name, ty))
}
/// 'var' _disambiguate_template template_list? optionally_typed_ident
fn variable_decl<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, ast::GlobalVariable<'a>> {
self.push_rule_span(Rule::VariableDecl, lexer);
let (template_list, _) = self.maybe_template_list(lexer, ctx)?;
let (name, ty) = self.optionally_typed_ident(lexer, ctx)?;
let init = if lexer.next_if(Token::Operation('=')) {
let handle = self.expression(lexer, ctx)?;
Some(handle)
} else {
None
};
lexer.expect(Token::Separator(';'))?;
self.pop_rule_span(lexer);
Ok(ast::GlobalVariable {
name,
template_list,
binding: None,
ty,
init,
doc_comments: Vec::new(),
memory_decorations: crate::MemoryDecorations::empty(),
})
}
fn struct_body<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, Vec<ast::StructMember<'a>>> {
let mut members = Vec::new();
let mut member_names = FastHashSet::default();
lexer.expect(Token::Paren('{'))?;
let mut ready = true;
while !lexer.next_if(Token::Paren('}')) {
if !ready {
return Err(Box::new(Error::Unexpected(
lexer.next().1,
ExpectedToken::Token(Token::Separator(',')),
)));
}
let doc_comments = lexer.accumulate_doc_comments();
let (mut size, mut align) = (ParsedAttribute::default(), ParsedAttribute::default());
self.push_rule_span(Rule::Attribute, lexer);
let mut bind_parser = BindingParser::default();
while lexer.next_if(Token::Attribute) {
match lexer.next_ident_with_span()? {
("size", name_span) => {
lexer.expect(Token::Paren('('))?;
let expr = self.expression(lexer, ctx)?;
lexer.next_if(Token::Separator(','));
lexer.expect(Token::Paren(')'))?;
size.set(expr, name_span)?;
}
("align", name_span) => {
lexer.expect(Token::Paren('('))?;
let expr = self.expression(lexer, ctx)?;
lexer.next_if(Token::Separator(','));
lexer.expect(Token::Paren(')'))?;
align.set(expr, name_span)?;
}
(word, word_span) => bind_parser.parse(self, lexer, word, word_span, ctx)?,
}
}
let bind_span = self.pop_rule_span(lexer);
let binding = bind_parser.finish(bind_span)?;
let name = lexer.next_ident()?;
lexer.expect(Token::Separator(':'))?;
let ty = self.type_specifier(lexer, ctx)?;
ready = lexer.next_if(Token::Separator(','));
members.push(ast::StructMember {
name,
ty,
binding,
size: size.value,
align: align.value,
doc_comments,
});
if !member_names.insert(name.name) {
return Err(Box::new(Error::Redefinition {
previous: members
.iter()
.find(|x| x.name.name == name.name)
.map(|x| x.name.span)
.unwrap(),
current: name.span,
}));
}
}
Ok(members)
}
fn maybe_template_list<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, (Vec<Handle<ast::Expression<'a>>>, Span)> {
let start = lexer.start_byte_offset();
if lexer.next_if(Token::TemplateArgsStart) {
let mut args = Vec::new();
args.push(self.expression(lexer, ctx)?);
while lexer.next_if(Token::Separator(',')) && lexer.peek().0 != Token::TemplateArgsEnd {
args.push(self.expression(lexer, ctx)?);
}
lexer.expect(Token::TemplateArgsEnd)?;
let span = lexer.span_from(start);
Ok((args, span))
} else {
Ok((Vec::new(), Span::UNDEFINED))
}
}
fn template_elaborated_ident<'a>(
&mut self,
word: &'a str,
span: Span,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, ast::TemplateElaboratedIdent<'a>> {
let ident = self.ident_expr(word, span, ctx);
let (template_list, template_list_span) = self.maybe_template_list(lexer, ctx)?;
Ok(ast::TemplateElaboratedIdent {
ident,
ident_span: span,
template_list,
template_list_span,
})
}
fn type_specifier<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, ast::TemplateElaboratedIdent<'a>> {
let (name, span) = lexer.next_ident_with_span()?;
self.template_elaborated_ident(name, span, lexer, ctx)
}
/// Parses assignment, increment and decrement statements
///
/// This does not consume or require a final `;` token. In the update
/// expression of a C-style `for` loop header, there is no terminating `;`.
fn variable_updating_statement<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
block: &mut ast::Block<'a>,
token: TokenSpan<'a>,
expected_token: ExpectedToken<'a>,
) -> Result<'a, ()> {
match token {
(Token::Word("_"), span) => {
lexer.expect(Token::Operation('='))?;
let expr = self.expression(lexer, ctx)?;
let span = lexer.span_with_start(span);
block.stmts.push(ast::Statement {
kind: ast::StatementKind::Phony(expr),
span,
});
return Ok(());
}
_ => {}
}
let target = self.lhs_expression(lexer, ctx, Some(token), expected_token)?;
let (op, value) = match lexer.next() {
(Token::Operation('='), _) => {
let value = self.expression(lexer, ctx)?;
(None, value)
}
(Token::AssignmentOperation(c), _) => {
use crate::BinaryOperator as Bo;
let op = match c {
'<' => Bo::ShiftLeft,
'>' => Bo::ShiftRight,
'+' => Bo::Add,
'-' => Bo::Subtract,
'*' => Bo::Multiply,
'/' => Bo::Divide,
'%' => Bo::Modulo,
'&' => Bo::And,
'|' => Bo::InclusiveOr,
'^' => Bo::ExclusiveOr,
// Note: `consume_token` shouldn't produce any other assignment ops
_ => unreachable!(),
};
let value = self.expression(lexer, ctx)?;
(Some(op), value)
}
op_token @ (Token::IncrementOperation | Token::DecrementOperation, _) => {
let op = match op_token.0 {
Token::IncrementOperation => ast::StatementKind::Increment,
Token::DecrementOperation => ast::StatementKind::Decrement,
_ => unreachable!(),
};
let span = lexer.span_with_start(token.1);
block.stmts.push(ast::Statement {
kind: op(target),
span,
});
return Ok(());
}
(_, span) => return Err(Box::new(Error::Unexpected(span, ExpectedToken::Assignment))),
};
let span = lexer.span_with_start(token.1);
block.stmts.push(ast::Statement {
kind: ast::StatementKind::Assign { target, op, value },
span,
});
Ok(())
}
/// Parse a function call statement.
///
/// This assumes that `token` has been consumed from the lexer.
///
/// This does not consume or require a final `;` token. In the update
/// expression of a C-style `for` loop header, there is no terminating `;`.
fn maybe_func_call_statement<'a>(
&mut self,
lexer: &mut Lexer<'a>,
context: &mut ExpressionContext<'a, '_, '_>,
block: &mut ast::Block<'a>,
token: TokenSpan<'a>,
) -> Result<'a, bool> {
let (name, name_span) = match token {
(Token::Word(name), span) => (name, span),
_ => return Ok(false),
};
let ident = self.template_elaborated_ident(name, name_span, lexer, context)?;
if ident.template_list.is_empty() && !matches!(lexer.peek(), (Token::Paren('('), _)) {
return Ok(false);
}
self.push_rule_span(Rule::SingularExpr, lexer);
let arguments = self.arguments(lexer, context)?;
let span = lexer.span_with_start(name_span);
block.stmts.push(ast::Statement {
kind: ast::StatementKind::Call(ast::CallPhrase {
function: ident,
arguments,
}),
span,
});
self.pop_rule_span(lexer);
Ok(true)
}
/// Parses func_call_statement and variable_updating_statement
///
/// This does not consume or require a final `;` token. In the update
/// expression of a C-style `for` loop header, there is no terminating `;`.
fn func_call_or_variable_updating_statement<'a>(
&mut self,
lexer: &mut Lexer<'a>,
context: &mut ExpressionContext<'a, '_, '_>,
block: &mut ast::Block<'a>,
token: TokenSpan<'a>,
expected_token: ExpectedToken<'a>,
) -> Result<'a, ()> {
if !self.maybe_func_call_statement(lexer, context, block, token)? {
self.variable_updating_statement(lexer, context, block, token, expected_token)?;
}
Ok(())
}
/// Parses variable_or_value_statement, func_call_statement and variable_updating_statement.
///
/// This is equivalent to the `for_init` production in the WGSL spec,
/// but it's also used for parsing these forms when they appear within a block,
/// hence the longer name.
///
/// This does not consume the following `;` token.
fn variable_or_value_or_func_call_or_variable_updating_statement<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
block: &mut ast::Block<'a>,
token: TokenSpan<'a>,
expected_token: ExpectedToken<'a>,
) -> Result<'a, ()> {
let local_decl = match token {
(Token::Word("let"), _) => {
let (name, given_ty) = self.optionally_typed_ident(lexer, ctx)?;
lexer.expect(Token::Operation('='))?;
let expr_id = self.expression(lexer, ctx)?;
let handle = ctx.declare_local(name)?;
ast::LocalDecl::Let(ast::Let {
name,
ty: given_ty,
init: expr_id,
handle,
})
}
(Token::Word("const"), _) => {
let (name, given_ty) = self.optionally_typed_ident(lexer, ctx)?;
lexer.expect(Token::Operation('='))?;
let expr_id = self.expression(lexer, ctx)?;
let handle = ctx.declare_local(name)?;
ast::LocalDecl::Const(ast::LocalConst {
name,
ty: given_ty,
init: expr_id,
handle,
})
}
(Token::Word("var"), _) => {
if lexer.next_if(Token::TemplateArgsStart) {
let (class_str, span) = lexer.next_ident_with_span()?;
if class_str != "function" {
return Err(Box::new(Error::InvalidLocalVariableAddressSpace(span)));
}
lexer.expect(Token::TemplateArgsEnd)?;
}
let (name, ty) = self.optionally_typed_ident(lexer, ctx)?;
let init = if lexer.next_if(Token::Operation('=')) {
let init = self.expression(lexer, ctx)?;
Some(init)
} else {
None
};
let handle = ctx.declare_local(name)?;
ast::LocalDecl::Var(ast::LocalVariable {
name,
ty,
init,
handle,
})
}
token => {
return self.func_call_or_variable_updating_statement(
lexer,
ctx,
block,
token,
expected_token,
);
}
};
let span = lexer.span_with_start(token.1);
block.stmts.push(ast::Statement {
kind: ast::StatementKind::LocalDecl(local_decl),
span,
});
Ok(())
}
fn statement<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
block: &mut ast::Block<'a>,
brace_nesting_level: u8,
) -> Result<'a, ()> {
self.track_recursion(|this| {
this.push_rule_span(Rule::Statement, lexer);
// We peek here instead of eagerly getting the next token since
// `Parser::block` expects its first token to be `{`.
//
// Most callers have a single path leading to the start of the block;
// `statement` is the only exception where there are multiple choices.
match lexer.peek() {
(token, _) if is_start_of_compound_statement(token) => {
let (inner, span) = this.block(lexer, ctx, brace_nesting_level)?;
block.stmts.push(ast::Statement {
kind: ast::StatementKind::Block(inner),
span,
});
this.pop_rule_span(lexer);
return Ok(());
}
_ => {}
}
let kind = match lexer.next() {
(Token::Separator(';'), _) => {
this.pop_rule_span(lexer);
return Ok(());
}
(Token::Word("return"), _) => {
let value = if lexer.peek().0 != Token::Separator(';') {
let handle = this.expression(lexer, ctx)?;
Some(handle)
} else {
None
};
lexer.expect(Token::Separator(';'))?;
ast::StatementKind::Return { value }
}
(Token::Word("if"), _) => {
let condition = this.expression(lexer, ctx)?;
let accept = this.block(lexer, ctx, brace_nesting_level)?.0;
let mut elsif_stack = Vec::new();
let mut elseif_span_start = lexer.start_byte_offset();
let mut reject = loop {
if !lexer.next_if(Token::Word("else")) {
break ast::Block::default();
}
if !lexer.next_if(Token::Word("if")) {
// ... else { ... }
break this.block(lexer, ctx, brace_nesting_level)?.0;
}
// ... else if (...) { ... }
let other_condition = this.expression(lexer, ctx)?;
let other_block = this.block(lexer, ctx, brace_nesting_level)?;
elsif_stack.push((elseif_span_start, other_condition, other_block));
elseif_span_start = lexer.start_byte_offset();
};
// reverse-fold the else-if blocks
//Note: we may consider uplifting this to the IR
for (other_span_start, other_cond, other_block) in elsif_stack.into_iter().rev()
{
let sub_stmt = ast::StatementKind::If {
condition: other_cond,
accept: other_block.0,
reject,
};
reject = ast::Block::default();
let span = lexer.span_from(other_span_start);
reject.stmts.push(ast::Statement {
kind: sub_stmt,
span,
})
}
ast::StatementKind::If {
condition,
accept,
reject,
}
}
(Token::Word("switch"), _) => {
let selector = this.expression(lexer, ctx)?;
let brace_span = lexer.expect_span(Token::Paren('{'))?;
let brace_nesting_level =
Self::increase_brace_nesting(brace_nesting_level, brace_span)?;
let mut cases = Vec::new();
loop {
// cases + default
match lexer.next() {
(Token::Word("case"), _) => {
// parse a list of values
let value = loop {
let value = this.switch_value(lexer, ctx)?;
if lexer.next_if(Token::Separator(',')) {
// list of values ends with ':' or a compound statement
let next_token = lexer.peek().0;
if next_token == Token::Separator(':')
|| is_start_of_compound_statement(next_token)
{
break value;
}
} else {
break value;
}
cases.push(ast::SwitchCase {
value,
body: ast::Block::default(),
fall_through: true,
});
};
lexer.next_if(Token::Separator(':'));
let body = this.block(lexer, ctx, brace_nesting_level)?.0;
cases.push(ast::SwitchCase {
value,
body,
fall_through: false,
});
}
(Token::Word("default"), _) => {
lexer.next_if(Token::Separator(':'));
let body = this.block(lexer, ctx, brace_nesting_level)?.0;
cases.push(ast::SwitchCase {
value: ast::SwitchValue::Default,
body,
fall_through: false,
});
}
(Token::Paren('}'), _) => break,
(_, span) => {
return Err(Box::new(Error::Unexpected(
span,
ExpectedToken::SwitchItem,
)))
}
}
}
ast::StatementKind::Switch { selector, cases }
}
(Token::Word("loop"), _) => this.r#loop(lexer, ctx, brace_nesting_level)?,
(Token::Word("while"), _) => {
let mut body = ast::Block::default();
let (condition, span) =
lexer.capture_span(|lexer| this.expression(lexer, ctx))?;
let mut reject = ast::Block::default();
reject.stmts.push(ast::Statement {
kind: ast::StatementKind::Break,
span,
});
body.stmts.push(ast::Statement {
kind: ast::StatementKind::If {
condition,
accept: ast::Block::default(),
reject,
},
span,
});
let (block, span) = this.block(lexer, ctx, brace_nesting_level)?;
body.stmts.push(ast::Statement {
kind: ast::StatementKind::Block(block),
span,
});
ast::StatementKind::Loop {
body,
continuing: ast::Block::default(),
break_if: None,
}
}
(Token::Word("for"), _) => {
lexer.expect(Token::Paren('('))?;
ctx.local_table.push_scope();
if !lexer.next_if(Token::Separator(';')) {
let token = lexer.next();
this.variable_or_value_or_func_call_or_variable_updating_statement(
lexer,
ctx,
block,
token,
ExpectedToken::ForInit,
)?;
lexer.expect(Token::Separator(';'))?;
};
let mut body = ast::Block::default();
if !lexer.next_if(Token::Separator(';')) {
let (condition, span) = lexer.capture_span(|lexer| -> Result<'_, _> {
let condition = this.expression(lexer, ctx)?;
lexer.expect(Token::Separator(';'))?;
Ok(condition)
})?;
let mut reject = ast::Block::default();
reject.stmts.push(ast::Statement {
kind: ast::StatementKind::Break,
span,
});
body.stmts.push(ast::Statement {
kind: ast::StatementKind::If {
condition,
accept: ast::Block::default(),
reject,
},
span,
});
};
let mut continuing = ast::Block::default();
if !lexer.next_if(Token::Paren(')')) {
let token = lexer.next();
this.func_call_or_variable_updating_statement(
lexer,
ctx,
&mut continuing,
token,
ExpectedToken::ForUpdate,
)?;
lexer.expect(Token::Paren(')'))?;
}
let (block, span) = this.block(lexer, ctx, brace_nesting_level)?;
body.stmts.push(ast::Statement {
kind: ast::StatementKind::Block(block),
span,
});
ctx.local_table.pop_scope();
ast::StatementKind::Loop {
body,
continuing,
break_if: None,
}
}
(Token::Word("break"), span) => {
// Check if the next token is an `if`, this indicates
// that the user tried to type out a `break if` which
// is illegal in this position.
let (peeked_token, peeked_span) = lexer.peek();
if let Token::Word("if") = peeked_token {
let span = span.until(&peeked_span);
return Err(Box::new(Error::InvalidBreakIf(span)));
}
lexer.expect(Token::Separator(';'))?;
ast::StatementKind::Break
}
(Token::Word("continue"), _) => {
lexer.expect(Token::Separator(';'))?;
ast::StatementKind::Continue
}
(Token::Word("discard"), _) => {
lexer.expect(Token::Separator(';'))?;
ast::StatementKind::Kill
}
(Token::Word("const_assert"), _) => {
// parentheses are optional
let paren = lexer.next_if(Token::Paren('('));
let condition = this.expression(lexer, ctx)?;
if paren {
lexer.expect(Token::Paren(')'))?;
}
lexer.expect(Token::Separator(';'))?;
ast::StatementKind::ConstAssert(condition)
}
token => {
this.variable_or_value_or_func_call_or_variable_updating_statement(
lexer,
ctx,
block,
token,
ExpectedToken::Statement,
)?;
lexer.expect(Token::Separator(';'))?;
this.pop_rule_span(lexer);
return Ok(());
}
};
let span = this.pop_rule_span(lexer);
block.stmts.push(ast::Statement { kind, span });
Ok(())
})
}
fn r#loop<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
brace_nesting_level: u8,
) -> Result<'a, ast::StatementKind<'a>> {
let mut body = ast::Block::default();
let mut continuing = ast::Block::default();
let mut break_if = None;
let brace_span = lexer.expect_span(Token::Paren('{'))?;
let brace_nesting_level = Self::increase_brace_nesting(brace_nesting_level, brace_span)?;
ctx.local_table.push_scope();
loop {
if lexer.next_if(Token::Word("continuing")) {
// Branch for the `continuing` block, this must be
// the last thing in the loop body
// Expect a opening brace to start the continuing block
let brace_span = lexer.expect_span(Token::Paren('{'))?;
let brace_nesting_level =
Self::increase_brace_nesting(brace_nesting_level, brace_span)?;
loop {
if lexer.next_if(Token::Word("break")) {
// Branch for the `break if` statement, this statement
// has the form `break if <expr>;` and must be the last
// statement in a continuing block
// The break must be followed by an `if` to form
// the break if
lexer.expect(Token::Word("if"))?;
let condition = self.expression(lexer, ctx)?;
// Set the condition of the break if to the newly parsed
// expression
break_if = Some(condition);
// Expect a semicolon to close the statement
lexer.expect(Token::Separator(';'))?;
// Expect a closing brace to close the continuing block,
// since the break if must be the last statement
lexer.expect(Token::Paren('}'))?;
// Stop parsing the continuing block
break;
} else if lexer.next_if(Token::Paren('}')) {
// If we encounter a closing brace it means we have reached
// the end of the continuing block and should stop processing
break;
} else {
// Otherwise try to parse a statement
self.statement(lexer, ctx, &mut continuing, brace_nesting_level)?;
}
}
// Since the continuing block must be the last part of the loop body,
// we expect to see a closing brace to end the loop body
lexer.expect(Token::Paren('}'))?;
break;
}
if lexer.next_if(Token::Paren('}')) {
// If we encounter a closing brace it means we have reached
// the end of the loop body and should stop processing
break;
}
// Otherwise try to parse a statement
self.statement(lexer, ctx, &mut body, brace_nesting_level)?;
}
ctx.local_table.pop_scope();
Ok(ast::StatementKind::Loop {
body,
continuing,
break_if,
})
}
/// compound_statement
fn block<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
brace_nesting_level: u8,
) -> Result<'a, (ast::Block<'a>, Span)> {
self.push_rule_span(Rule::Block, lexer);
ctx.local_table.push_scope();
let mut diagnostic_filters = DiagnosticFilterMap::new();
self.push_rule_span(Rule::Attribute, lexer);
while lexer.next_if(Token::Attribute) {
let (name, name_span) = lexer.next_ident_with_span()?;
if let Some(DirectiveKind::Diagnostic) = DirectiveKind::from_ident(name) {
let filter = self.diagnostic_filter(lexer)?;
let span = self.peek_rule_span(lexer);
diagnostic_filters
.add(filter, span, ShouldConflictOnFullDuplicate::Yes)
.map_err(|e| Box::new(e.into()))?;
} else {
return Err(Box::new(Error::Unexpected(
name_span,
ExpectedToken::DiagnosticAttribute,
)));
}
}
self.pop_rule_span(lexer);
if !diagnostic_filters.is_empty() {
return Err(Box::new(
Error::DiagnosticAttributeNotYetImplementedAtParseSite {
site_name_plural: "compound statements",
spans: diagnostic_filters.spans().collect(),
},
));
}
let brace_span = lexer.expect_span(Token::Paren('{'))?;
let brace_nesting_level = Self::increase_brace_nesting(brace_nesting_level, brace_span)?;
let mut block = ast::Block::default();
while !lexer.next_if(Token::Paren('}')) {
self.statement(lexer, ctx, &mut block, brace_nesting_level)?;
}
ctx.local_table.pop_scope();
let span = self.pop_rule_span(lexer);
Ok((block, span))
}
fn varying_binding<'a>(
&mut self,
lexer: &mut Lexer<'a>,
ctx: &mut ExpressionContext<'a, '_, '_>,
) -> Result<'a, Option<ast::Binding<'a>>> {
let mut bind_parser = BindingParser::default();
self.push_rule_span(Rule::Attribute, lexer);
while lexer.next_if(Token::Attribute) {
let (word, span) = lexer.next_ident_with_span()?;
bind_parser.parse(self, lexer, word, span, ctx)?;
}
let span = self.pop_rule_span(lexer);
bind_parser.finish(span)
}
fn function_decl<'a>(
&mut self,
lexer: &mut Lexer<'a>,
diagnostic_filter_leaf: Option<Handle<DiagnosticFilterNode>>,
must_use: Option<Span>,
out: &mut ast::TranslationUnit<'a>,
dependencies: &mut FastIndexSet<ast::Dependency<'a>>,
) -> Result<'a, ast::Function<'a>> {
self.push_rule_span(Rule::FunctionDecl, lexer);
// read function name
let fun_name = lexer.next_ident()?;
let mut locals = Arena::new();
let mut ctx = ExpressionContext {
expressions: &mut out.expressions,
local_table: &mut SymbolTable::default(),
locals: &mut locals,
unresolved: dependencies,
};
// start a scope that contains arguments as well as the function body
ctx.local_table.push_scope();
// Reduce lookup scope to parse the parameter list and return type
// avoiding identifier lookup to match newly declared param names.
ctx.local_table.reduce_lookup_scope();
// read parameter list
let mut arguments = Vec::new();
lexer.expect(Token::Paren('('))?;
let mut ready = true;
while !lexer.next_if(Token::Paren(')')) {
if !ready {
return Err(Box::new(Error::Unexpected(
lexer.next().1,
ExpectedToken::Token(Token::Separator(',')),
)));
}
let binding = self.varying_binding(lexer, &mut ctx)?;
let param_name = lexer.next_ident()?;
lexer.expect(Token::Separator(':'))?;
let param_type = self.type_specifier(lexer, &mut ctx)?;
let handle = ctx.declare_local(param_name)?;
arguments.push(ast::FunctionArgument {
name: param_name,
ty: param_type,
binding,
handle,
});
ready = lexer.next_if(Token::Separator(','));
}
// read return type
let result = if lexer.next_if(Token::Arrow) {
let binding = self.varying_binding(lexer, &mut ctx)?;
let ty = self.type_specifier(lexer, &mut ctx)?;
let must_use = must_use.is_some();
Some(ast::FunctionResult {
ty,
binding,
must_use,
})
} else if let Some(must_use) = must_use {
return Err(Box::new(Error::FunctionMustUseReturnsVoid(
must_use,
self.peek_rule_span(lexer),
)));
} else {
None
};
ctx.local_table.reset_lookup_scope();
// do not use `self.block` here, since we must not push a new scope
lexer.expect(Token::Paren('{'))?;
let brace_nesting_level = 1;
let mut body = ast::Block::default();
while !lexer.next_if(Token::Paren('}')) {
self.statement(lexer, &mut ctx, &mut body, brace_nesting_level)?;
}
ctx.local_table.pop_scope();
let fun = ast::Function {
entry_point: None,
name: fun_name,
arguments,
result,
body,
diagnostic_filter_leaf,
doc_comments: Vec::new(),
};
// done
self.pop_rule_span(lexer);
Ok(fun)
}
fn directive_ident_list<'a>(
&self,
lexer: &mut Lexer<'a>,
handler: impl FnMut(&'a str, Span) -> Result<'a, ()>,
) -> Result<'a, ()> {
let mut handler = handler;
'next_arg: loop {
let (ident, span) = lexer.next_ident_with_span()?;
handler(ident, span)?;
let expected_token = match lexer.peek().0 {
Token::Separator(',') => {
let _ = lexer.next();
if matches!(lexer.peek().0, Token::Word(..)) {
continue 'next_arg;
}
ExpectedToken::AfterIdentListComma
}
_ => ExpectedToken::AfterIdentListArg,
};
if !matches!(lexer.next().0, Token::Separator(';')) {
return Err(Box::new(Error::Unexpected(span, expected_token)));
}
break Ok(());
}
}
fn global_decl<'a>(
&mut self,
lexer: &mut Lexer<'a>,
out: &mut ast::TranslationUnit<'a>,
) -> Result<'a, ()> {
let doc_comments = lexer.accumulate_doc_comments();
// read attributes
let mut binding = None;
let mut stage = ParsedAttribute::default();
// Span in case we need to report an error for a shader stage missing something (e.g. its workgroup size).
// Doesn't need to be set in the vertex and fragment stages because they don't have errors like that.
let mut shader_stage_error_span = Span::new(0, 0);
let mut workgroup_size = ParsedAttribute::default();
let mut early_depth_test = ParsedAttribute::default();
let (mut bind_index, mut bind_group) =
(ParsedAttribute::default(), ParsedAttribute::default());
let mut id = ParsedAttribute::default();
// the payload variable for a mesh shader
let mut payload = ParsedAttribute::default();
// the incoming payload from a traceRay call
let mut incoming_payload = ParsedAttribute::default();
let mut mesh_output = ParsedAttribute::default();
let mut must_use: ParsedAttribute<Span> = ParsedAttribute::default();
let mut memory_decorations = crate::MemoryDecorations::empty();
let mut dependencies = FastIndexSet::default();
let mut ctx = ExpressionContext {
expressions: &mut out.expressions,
local_table: &mut SymbolTable::default(),
locals: &mut Arena::new(),
unresolved: &mut dependencies,
};
let mut diagnostic_filters = DiagnosticFilterMap::new();
let ensure_no_diag_attrs = |on_what, filters: DiagnosticFilterMap| -> Result<()> {
if filters.is_empty() {
Ok(())
} else {
Err(Box::new(Error::DiagnosticAttributeNotSupported {
on_what,
spans: filters.spans().collect(),
}))
}
};
self.push_rule_span(Rule::Attribute, lexer);
while lexer.next_if(Token::Attribute) {
let (name, name_span) = lexer.next_ident_with_span()?;
if let Some(DirectiveKind::Diagnostic) = DirectiveKind::from_ident(name) {
let filter = self.diagnostic_filter(lexer)?;
let span = self.peek_rule_span(lexer);
diagnostic_filters
.add(filter, span, ShouldConflictOnFullDuplicate::Yes)
.map_err(|e| Box::new(e.into()))?;
continue;
}
match name {
"binding" => {
lexer.expect(Token::Paren('('))?;
bind_index.set(self.expression(lexer, &mut ctx)?, name_span)?;
lexer.next_if(Token::Separator(','));
lexer.expect(Token::Paren(')'))?;
}
"group" => {
lexer.expect(Token::Paren('('))?;
bind_group.set(self.expression(lexer, &mut ctx)?, name_span)?;
lexer.next_if(Token::Separator(','));
lexer.expect(Token::Paren(')'))?;
}
"id" => {
lexer.expect(Token::Paren('('))?;
id.set(self.expression(lexer, &mut ctx)?, name_span)?;
lexer.next_if(Token::Separator(','));
lexer.expect(Token::Paren(')'))?;
}
"vertex" => {
stage.set(ShaderStage::Vertex, name_span)?;
}
"fragment" => {
stage.set(ShaderStage::Fragment, name_span)?;
}
"compute" => {
stage.set(ShaderStage::Compute, name_span)?;
shader_stage_error_span = name_span;
}
"task" => {
lexer.require_enable_extension(
ImplementedEnableExtension::WgpuMeshShader,
name_span,
)?;
stage.set(ShaderStage::Task, name_span)?;
shader_stage_error_span = name_span;
}
"mesh" => {
lexer.require_enable_extension(
ImplementedEnableExtension::WgpuMeshShader,
name_span,
)?;
stage.set(ShaderStage::Mesh, name_span)?;
shader_stage_error_span = name_span;
lexer.expect(Token::Paren('('))?;
mesh_output.set(lexer.next_ident_with_span()?, name_span)?;
lexer.expect(Token::Paren(')'))?;
}
"ray_generation" => {
lexer.require_enable_extension(
ImplementedEnableExtension::WgpuRayTracingPipeline,
name_span,
)?;
stage.set(ShaderStage::RayGeneration, name_span)?;
shader_stage_error_span = name_span;
}
"any_hit" => {
lexer.require_enable_extension(
ImplementedEnableExtension::WgpuRayTracingPipeline,
name_span,
)?;
stage.set(ShaderStage::AnyHit, name_span)?;
shader_stage_error_span = name_span;
}
"closest_hit" => {
lexer.require_enable_extension(
ImplementedEnableExtension::WgpuRayTracingPipeline,
name_span,
)?;
stage.set(ShaderStage::ClosestHit, name_span)?;
shader_stage_error_span = name_span;
}
"miss" => {
lexer.require_enable_extension(
ImplementedEnableExtension::WgpuRayTracingPipeline,
name_span,
)?;
stage.set(ShaderStage::Miss, name_span)?;
shader_stage_error_span = name_span;
}
"payload" => {
lexer.require_enable_extension(
ImplementedEnableExtension::WgpuMeshShader,
name_span,
)?;
lexer.expect(Token::Paren('('))?;
payload.set(lexer.next_ident_with_span()?, name_span)?;
lexer.expect(Token::Paren(')'))?;
}
"incoming_payload" => {
lexer.require_enable_extension(
ImplementedEnableExtension::WgpuRayTracingPipeline,
name_span,
)?;
lexer.expect(Token::Paren('('))?;
incoming_payload.set(lexer.next_ident_with_span()?, name_span)?;
lexer.expect(Token::Paren(')'))?;
}
"workgroup_size" => {
lexer.expect(Token::Paren('('))?;
let mut new_workgroup_size = [None; 3];
for size in new_workgroup_size.iter_mut() {
*size = Some(self.expression(lexer, &mut ctx)?);
match lexer.next() {
(Token::Paren(')'), _) => break,
(Token::Separator(','), _) => {
if lexer.next_if(Token::Paren(')')) {
break;
}
}
other => {
return Err(Box::new(Error::Unexpected(
other.1,
ExpectedToken::WorkgroupSizeSeparator,
)))
}
}
}
workgroup_size.set(new_workgroup_size, name_span)?;
}
"early_depth_test" => {
lexer.expect(Token::Paren('('))?;
let (ident, ident_span) = lexer.next_ident_with_span()?;
let value = if ident == "force" {
crate::EarlyDepthTest::Force
} else {
crate::EarlyDepthTest::Allow {
conservative: conv::map_conservative_depth(ident, ident_span)?,
}
};
lexer.expect(Token::Paren(')'))?;
early_depth_test.set(value, name_span)?;
}
"must_use" => {
must_use.set(name_span, name_span)?;
}
"coherent" => {
memory_decorations |= crate::MemoryDecorations::COHERENT;
}
"volatile" => {
memory_decorations |= crate::MemoryDecorations::VOLATILE;
}
_ => return Err(Box::new(Error::UnknownAttribute(name_span))),
}
}
let attrib_span = self.pop_rule_span(lexer);
match (bind_group.value, bind_index.value) {
(Some(group), Some(index)) => {
binding = Some(ast::ResourceBinding {
group,
binding: index,
});
}
(Some(_), None) => {
return Err(Box::new(Error::MissingAttribute("binding", attrib_span)))
}
(None, Some(_)) => return Err(Box::new(Error::MissingAttribute("group", attrib_span))),
(None, None) => {}
}
// read item
let start = lexer.start_byte_offset();
let kind = match lexer.next() {
(Token::Separator(';'), _) => {
ensure_no_diag_attrs(
DiagnosticAttributeNotSupportedPosition::SemicolonInModulePosition,
diagnostic_filters,
)?;
None
}
(Token::Word(word), directive_span) if DirectiveKind::from_ident(word).is_some() => {
return Err(Box::new(Error::DirectiveAfterFirstGlobalDecl {
directive_span,
}));
}
(Token::Word("struct"), _) => {
ensure_no_diag_attrs("`struct`s".into(), diagnostic_filters)?;
let name = lexer.next_ident()?;
let members = self.struct_body(lexer, &mut ctx)?;
Some(ast::GlobalDeclKind::Struct(ast::Struct {
name,
members,
doc_comments,
}))
}
(Token::Word("alias"), _) => {
ensure_no_diag_attrs("`alias`es".into(), diagnostic_filters)?;
let name = lexer.next_ident()?;
lexer.expect(Token::Operation('='))?;
let ty = self.type_specifier(lexer, &mut ctx)?;
lexer.expect(Token::Separator(';'))?;
Some(ast::GlobalDeclKind::Type(ast::TypeAlias { name, ty }))
}
(Token::Word("const"), _) => {
ensure_no_diag_attrs("`const`s".into(), diagnostic_filters)?;
let (name, ty) = self.optionally_typed_ident(lexer, &mut ctx)?;
lexer.expect(Token::Operation('='))?;
let init = self.expression(lexer, &mut ctx)?;
lexer.expect(Token::Separator(';'))?;
Some(ast::GlobalDeclKind::Const(ast::Const {
name,
ty,
init,
doc_comments,
}))
}
(Token::Word("override"), _) => {
ensure_no_diag_attrs("`override`s".into(), diagnostic_filters)?;
let (name, ty) = self.optionally_typed_ident(lexer, &mut ctx)?;
let init = if lexer.next_if(Token::Operation('=')) {
Some(self.expression(lexer, &mut ctx)?)
} else {
None
};
lexer.expect(Token::Separator(';'))?;
Some(ast::GlobalDeclKind::Override(ast::Override {
name,
id: id.value,
ty,
init,
}))
}
(Token::Word("var"), _) => {
ensure_no_diag_attrs("`var`s".into(), diagnostic_filters)?;
let mut var = self.variable_decl(lexer, &mut ctx)?;
var.binding = binding.take();
var.doc_comments = doc_comments;
var.memory_decorations = memory_decorations;
Some(ast::GlobalDeclKind::Var(var))
}
(Token::Word("fn"), _) => {
let diagnostic_filter_leaf = Self::write_diagnostic_filters(
&mut out.diagnostic_filters,
diagnostic_filters,
out.diagnostic_filter_leaf,
);
let function = self.function_decl(
lexer,
diagnostic_filter_leaf,
must_use.value,
out,
&mut dependencies,
)?;
Some(ast::GlobalDeclKind::Fn(ast::Function {
entry_point: if let Some(stage) = stage.value {
if stage.compute_like() && workgroup_size.value.is_none() {
return Err(Box::new(Error::MissingWorkgroupSize(
shader_stage_error_span,
)));
}
match stage {
ShaderStage::AnyHit | ShaderStage::ClosestHit | ShaderStage::Miss => {
if incoming_payload.value.is_none() {
return Err(Box::new(Error::MissingIncomingPayload(
shader_stage_error_span,
)));
}
}
_ => {}
}
Some(ast::EntryPoint {
stage,
early_depth_test: early_depth_test.value,
workgroup_size: workgroup_size.value,
mesh_output_variable: mesh_output.value,
task_payload: payload.value,
ray_incoming_payload: incoming_payload.value,
})
} else {
None
},
doc_comments,
..function
}))
}
(Token::Word("const_assert"), _) => {
ensure_no_diag_attrs("`const_assert`s".into(), diagnostic_filters)?;
// parentheses are optional
let paren = lexer.next_if(Token::Paren('('));
let condition = self.expression(lexer, &mut ctx)?;
if paren {
lexer.expect(Token::Paren(')'))?;
}
lexer.expect(Token::Separator(';'))?;
Some(ast::GlobalDeclKind::ConstAssert(condition))
}
(Token::End, _) => return Ok(()),
other => {
return Err(Box::new(Error::Unexpected(
other.1,
ExpectedToken::GlobalItem,
)))
}
};
if let Some(kind) = kind {
out.decls.append(
ast::GlobalDecl { kind, dependencies },
lexer.span_from(start),
);
}
if !self.rules.is_empty() {
log::error!("Reached the end of global decl, but rule stack is not empty");
log::error!("Rules: {:?}", self.rules);
return Err(Box::new(Error::Internal("rule stack is not empty")));
};
match binding {
None => Ok(()),
Some(_) => Err(Box::new(Error::Internal(
"we had the attribute but no var?",
))),
}
}
pub fn parse<'a>(
&mut self,
source: &'a str,
options: &Options,
) -> Result<'a, ast::TranslationUnit<'a>> {
self.reset();
let mut lexer = Lexer::new(source, !options.parse_doc_comments);
let mut tu = ast::TranslationUnit::default();
let mut enable_extensions = EnableExtensions::empty();
let mut diagnostic_filters = DiagnosticFilterMap::new();
// Parse module doc comments.
tu.doc_comments = lexer.accumulate_module_doc_comments();
// Parse directives.
while let (Token::Word(word), _) = lexer.peek() {
if let Some(kind) = DirectiveKind::from_ident(word) {
self.push_rule_span(Rule::Directive, &mut lexer);
let _ = lexer.next_ident_with_span().unwrap();
match kind {
DirectiveKind::Diagnostic => {
let diagnostic_filter = self.diagnostic_filter(&mut lexer)?;
let span = self.peek_rule_span(&lexer);
diagnostic_filters
.add(diagnostic_filter, span, ShouldConflictOnFullDuplicate::No)
.map_err(|e| Box::new(e.into()))?;
lexer.expect(Token::Separator(';'))?;
}
DirectiveKind::Enable => {
self.directive_ident_list(&mut lexer, |ident, span| {
let kind = EnableExtension::from_ident(ident, span)?;
let extension = match kind {
EnableExtension::Implemented(kind) => kind,
EnableExtension::Unimplemented(kind) => {
return Err(Box::new(Error::EnableExtensionNotYetImplemented {
kind,
span,
}))
}
};
// Check if the required capability is supported
let required_capability = extension.capability();
if !options.capabilities.contains(required_capability) {
return Err(Box::new(Error::EnableExtensionNotSupported {
kind,
span,
}));
}
enable_extensions.add(extension);
Ok(())
})?;
}
DirectiveKind::Requires => {
self.directive_ident_list(&mut lexer, |ident, span| {
match LanguageExtension::from_ident(ident) {
Some(LanguageExtension::Implemented(_kind)) => {
// NOTE: No further validation is needed for an extension, so
// just throw parsed information away. If we ever want to apply
// what we've parsed to diagnostics, maybe we'll want to refer
// to enabled extensions later?
Ok(())
}
Some(LanguageExtension::Unimplemented(kind)) => {
Err(Box::new(Error::LanguageExtensionNotYetImplemented {
kind,
span,
}))
}
None => Err(Box::new(Error::UnknownLanguageExtension(span, ident))),
}
})?;
}
}
self.pop_rule_span(&lexer);
} else {
break;
}
}
lexer.enable_extensions = enable_extensions;
tu.enable_extensions = enable_extensions;
tu.diagnostic_filter_leaf =
Self::write_diagnostic_filters(&mut tu.diagnostic_filters, diagnostic_filters, None);
loop {
match self.global_decl(&mut lexer, &mut tu) {
Err(error) => return Err(error),
Ok(()) => {
if lexer.peek().0 == Token::End {
break;
}
}
}
}
Ok(tu)
}
fn increase_brace_nesting(brace_nesting_level: u8, brace_span: Span) -> Result<'static, u8> {
// From [spec.](https://gpuweb.github.io/gpuweb/wgsl/#limits):
//
// > § 2.4. Limits
// >
// > …
// >
// > Maximum nesting depth of brace-enclosed statements in a function[:] 127
const BRACE_NESTING_MAXIMUM: u8 = 127;
if brace_nesting_level + 1 > BRACE_NESTING_MAXIMUM {
return Err(Box::new(Error::ExceededLimitForNestedBraces {
span: brace_span,
limit: BRACE_NESTING_MAXIMUM,
}));
}
Ok(brace_nesting_level + 1)
}
fn diagnostic_filter<'a>(&self, lexer: &mut Lexer<'a>) -> Result<'a, DiagnosticFilter> {
lexer.expect(Token::Paren('('))?;
let (severity_control_name, severity_control_name_span) = lexer.next_ident_with_span()?;
let new_severity = diagnostic_filter::Severity::from_wgsl_ident(severity_control_name)
.ok_or(Error::DiagnosticInvalidSeverity {
severity_control_name_span,
})?;
lexer.expect(Token::Separator(','))?;
let (diagnostic_name_token, diagnostic_name_token_span) = lexer.next_ident_with_span()?;
let triggering_rule = if lexer.next_if(Token::Separator('.')) {
let (ident, _span) = lexer.next_ident_with_span()?;
FilterableTriggeringRule::User(Box::new([diagnostic_name_token.into(), ident.into()]))
} else {
let diagnostic_rule_name = diagnostic_name_token;
let diagnostic_rule_name_span = diagnostic_name_token_span;
if let Some(triggering_rule) =
StandardFilterableTriggeringRule::from_wgsl_ident(diagnostic_rule_name)
{
FilterableTriggeringRule::Standard(triggering_rule)
} else {
diagnostic_filter::Severity::Warning.report_wgsl_parse_diag(
Box::new(Error::UnknownDiagnosticRuleName(diagnostic_rule_name_span)),
lexer.source,
)?;
FilterableTriggeringRule::Unknown(diagnostic_rule_name.into())
}
};
let filter = DiagnosticFilter {
triggering_rule,
new_severity,
};
lexer.next_if(Token::Separator(','));
lexer.expect(Token::Paren(')'))?;
Ok(filter)
}
pub(crate) fn write_diagnostic_filters(
arena: &mut Arena<DiagnosticFilterNode>,
filters: DiagnosticFilterMap,
parent: Option<Handle<DiagnosticFilterNode>>,
) -> Option<Handle<DiagnosticFilterNode>> {
filters
.into_iter()
.fold(parent, |parent, (triggering_rule, (new_severity, span))| {
Some(arena.append(
DiagnosticFilterNode {
inner: DiagnosticFilter {
new_severity,
triggering_rule,
},
parent,
},
span,
))
})
}
}
const fn is_start_of_compound_statement<'a>(token: Token<'a>) -> bool {
matches!(token, Token::Attribute | Token::Paren('{'))
}