diff options
Diffstat (limited to 'third_party/rust/naga/src/front/glsl/parser.rs')
| -rw-r--r-- | third_party/rust/naga/src/front/glsl/parser.rs | 431 |
1 files changed, 431 insertions, 0 deletions
diff --git a/third_party/rust/naga/src/front/glsl/parser.rs b/third_party/rust/naga/src/front/glsl/parser.rs new file mode 100644 index 0000000000..851d2e1d79 --- /dev/null +++ b/third_party/rust/naga/src/front/glsl/parser.rs @@ -0,0 +1,431 @@ +use super::{ + ast::{FunctionKind, Profile, TypeQualifiers}, + context::{Context, ExprPos}, + error::ExpectedToken, + error::{Error, ErrorKind}, + lex::{Lexer, LexerResultKind}, + token::{Directive, DirectiveKind}, + token::{Token, TokenValue}, + variables::{GlobalOrConstant, VarDeclaration}, + Frontend, Result, +}; +use crate::{arena::Handle, proc::U32EvalError, Expression, Module, Span, Type}; +use pp_rs::token::{PreprocessorError, Token as PPToken, TokenValue as PPTokenValue}; +use std::iter::Peekable; + +mod declarations; +mod expressions; +mod functions; +mod types; + +pub struct ParsingContext<'source> { + lexer: Peekable<Lexer<'source>>, + /// Used to store tokens already consumed by the parser but that need to be backtracked + backtracked_token: Option<Token>, + last_meta: Span, +} + +impl<'source> ParsingContext<'source> { + pub fn new(lexer: Lexer<'source>) -> Self { + ParsingContext { + lexer: lexer.peekable(), + backtracked_token: None, + last_meta: Span::default(), + } + } + + /// Helper method for backtracking from a consumed token + /// + /// This method should always be used instead of assigning to `backtracked_token` since + /// it validates that backtracking hasn't occurred more than one time in a row + /// + /// # Panics + /// - If the parser already backtracked without bumping in between + pub fn backtrack(&mut self, token: Token) -> Result<()> { + // This should never happen + if let Some(ref prev_token) = self.backtracked_token { + return Err(Error { + kind: ErrorKind::InternalError("The parser tried to backtrack twice in a row"), + meta: prev_token.meta, + }); + } + + self.backtracked_token = Some(token); + + Ok(()) + } + + pub fn expect_ident(&mut self, frontend: &mut Frontend) -> Result<(String, Span)> { + let token = self.bump(frontend)?; + + match token.value { + TokenValue::Identifier(name) => Ok((name, token.meta)), + _ => Err(Error { + kind: ErrorKind::InvalidToken(token.value, vec![ExpectedToken::Identifier]), + meta: token.meta, + }), + } + } + + pub fn expect(&mut self, frontend: &mut Frontend, value: TokenValue) -> Result<Token> { + let token = self.bump(frontend)?; + + if token.value != value { + Err(Error { + kind: ErrorKind::InvalidToken(token.value, vec![value.into()]), + meta: token.meta, + }) + } else { + Ok(token) + } + } + + pub fn next(&mut self, frontend: &mut Frontend) -> Option<Token> { + loop { + if let Some(token) = self.backtracked_token.take() { + self.last_meta = token.meta; + break Some(token); + } + + let res = self.lexer.next()?; + + match res.kind { + LexerResultKind::Token(token) => { + self.last_meta = token.meta; + break Some(token); + } + LexerResultKind::Directive(directive) => { + frontend.handle_directive(directive, res.meta) + } + LexerResultKind::Error(error) => frontend.errors.push(Error { + kind: ErrorKind::PreprocessorError(error), + meta: res.meta, + }), + } + } + } + + pub fn bump(&mut self, frontend: &mut Frontend) -> Result<Token> { + self.next(frontend).ok_or(Error { + kind: ErrorKind::EndOfFile, + meta: self.last_meta, + }) + } + + /// Returns None on the end of the file rather than an error like other methods + pub fn bump_if(&mut self, frontend: &mut Frontend, value: TokenValue) -> Option<Token> { + if self.peek(frontend).filter(|t| t.value == value).is_some() { + self.bump(frontend).ok() + } else { + None + } + } + + pub fn peek(&mut self, frontend: &mut Frontend) -> Option<&Token> { + loop { + if let Some(ref token) = self.backtracked_token { + break Some(token); + } + + match self.lexer.peek()?.kind { + LexerResultKind::Token(_) => { + let res = self.lexer.peek()?; + + match res.kind { + LexerResultKind::Token(ref token) => break Some(token), + _ => unreachable!(), + } + } + LexerResultKind::Error(_) | LexerResultKind::Directive(_) => { + let res = self.lexer.next()?; + + match res.kind { + LexerResultKind::Directive(directive) => { + frontend.handle_directive(directive, res.meta) + } + LexerResultKind::Error(error) => frontend.errors.push(Error { + kind: ErrorKind::PreprocessorError(error), + meta: res.meta, + }), + LexerResultKind::Token(_) => unreachable!(), + } + } + } + } + } + + pub fn expect_peek(&mut self, frontend: &mut Frontend) -> Result<&Token> { + let meta = self.last_meta; + self.peek(frontend).ok_or(Error { + kind: ErrorKind::EndOfFile, + meta, + }) + } + + pub fn parse(&mut self, frontend: &mut Frontend) -> Result<Module> { + let mut module = Module::default(); + + // Body and expression arena for global initialization + let mut ctx = Context::new(frontend, &mut module, false)?; + + while self.peek(frontend).is_some() { + self.parse_external_declaration(frontend, &mut ctx)?; + } + + // Add an `EntryPoint` to `parser.module` for `main`, if a + // suitable overload exists. Error out if we can't find one. + if let Some(declaration) = frontend.lookup_function.get("main") { + for decl in declaration.overloads.iter() { + if let FunctionKind::Call(handle) = decl.kind { + if decl.defined && decl.parameters.is_empty() { + frontend.add_entry_point(handle, ctx)?; + return Ok(module); + } + } + } + } + + Err(Error { + kind: ErrorKind::SemanticError("Missing entry point".into()), + meta: Span::default(), + }) + } + + fn parse_uint_constant( + &mut self, + frontend: &mut Frontend, + ctx: &mut Context, + ) -> Result<(u32, Span)> { + let (const_expr, meta) = self.parse_constant_expression(frontend, ctx.module)?; + + let res = ctx.module.to_ctx().eval_expr_to_u32(const_expr); + + let int = match res { + Ok(value) => Ok(value), + Err(U32EvalError::Negative) => Err(Error { + kind: ErrorKind::SemanticError("int constant overflows".into()), + meta, + }), + Err(U32EvalError::NonConst) => Err(Error { + kind: ErrorKind::SemanticError("Expected a uint constant".into()), + meta, + }), + }?; + + Ok((int, meta)) + } + + fn parse_constant_expression( + &mut self, + frontend: &mut Frontend, + module: &mut Module, + ) -> Result<(Handle<Expression>, Span)> { + let mut ctx = Context::new(frontend, module, true)?; + + let mut stmt_ctx = ctx.stmt_ctx(); + let expr = self.parse_conditional(frontend, &mut ctx, &mut stmt_ctx, None)?; + let (root, meta) = ctx.lower_expect(stmt_ctx, frontend, expr, ExprPos::Rhs)?; + + Ok((root, meta)) + } +} + +impl Frontend { + fn handle_directive(&mut self, directive: Directive, meta: Span) { + let mut tokens = directive.tokens.into_iter(); + + match directive.kind { + DirectiveKind::Version { is_first_directive } => { + if !is_first_directive { + self.errors.push(Error { + kind: ErrorKind::SemanticError( + "#version must occur first in shader".into(), + ), + meta, + }) + } + + match tokens.next() { + Some(PPToken { + value: PPTokenValue::Integer(int), + location, + }) => match int.value { + 440 | 450 | 460 => self.meta.version = int.value as u16, + _ => self.errors.push(Error { + kind: ErrorKind::InvalidVersion(int.value), + meta: location.into(), + }), + }, + Some(PPToken { value, location }) => self.errors.push(Error { + kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedToken( + value, + )), + meta: location.into(), + }), + None => self.errors.push(Error { + kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedNewLine), + meta, + }), + }; + + match tokens.next() { + Some(PPToken { + value: PPTokenValue::Ident(name), + location, + }) => match name.as_str() { + "core" => self.meta.profile = Profile::Core, + _ => self.errors.push(Error { + kind: ErrorKind::InvalidProfile(name), + meta: location.into(), + }), + }, + Some(PPToken { value, location }) => self.errors.push(Error { + kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedToken( + value, + )), + meta: location.into(), + }), + None => {} + }; + + if let Some(PPToken { value, location }) = tokens.next() { + self.errors.push(Error { + kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedToken( + value, + )), + meta: location.into(), + }) + } + } + DirectiveKind::Extension => { + // TODO: Proper extension handling + // - Checking for extension support in the compiler + // - Handle behaviors such as warn + // - Handle the all extension + let name = match tokens.next() { + Some(PPToken { + value: PPTokenValue::Ident(name), + .. + }) => Some(name), + Some(PPToken { value, location }) => { + self.errors.push(Error { + kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedToken( + value, + )), + meta: location.into(), + }); + + None + } + None => { + self.errors.push(Error { + kind: ErrorKind::PreprocessorError( + PreprocessorError::UnexpectedNewLine, + ), + meta, + }); + + None + } + }; + + match tokens.next() { + Some(PPToken { + value: PPTokenValue::Punct(pp_rs::token::Punct::Colon), + .. + }) => {} + Some(PPToken { value, location }) => self.errors.push(Error { + kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedToken( + value, + )), + meta: location.into(), + }), + None => self.errors.push(Error { + kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedNewLine), + meta, + }), + }; + + match tokens.next() { + Some(PPToken { + value: PPTokenValue::Ident(behavior), + location, + }) => match behavior.as_str() { + "require" | "enable" | "warn" | "disable" => { + if let Some(name) = name { + self.meta.extensions.insert(name); + } + } + _ => self.errors.push(Error { + kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedToken( + PPTokenValue::Ident(behavior), + )), + meta: location.into(), + }), + }, + Some(PPToken { value, location }) => self.errors.push(Error { + kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedToken( + value, + )), + meta: location.into(), + }), + None => self.errors.push(Error { + kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedNewLine), + meta, + }), + } + + if let Some(PPToken { value, location }) = tokens.next() { + self.errors.push(Error { + kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedToken( + value, + )), + meta: location.into(), + }) + } + } + DirectiveKind::Pragma => { + // TODO: handle some common pragmas? + } + } + } +} + +pub struct DeclarationContext<'ctx, 'qualifiers, 'a> { + qualifiers: TypeQualifiers<'qualifiers>, + /// Indicates a global declaration + external: bool, + is_inside_loop: bool, + ctx: &'ctx mut Context<'a>, +} + +impl<'ctx, 'qualifiers, 'a> DeclarationContext<'ctx, 'qualifiers, 'a> { + fn add_var( + &mut self, + frontend: &mut Frontend, + ty: Handle<Type>, + name: String, + init: Option<Handle<Expression>>, + meta: Span, + ) -> Result<Handle<Expression>> { + let decl = VarDeclaration { + qualifiers: &mut self.qualifiers, + ty, + name: Some(name), + init, + meta, + }; + + match self.external { + true => { + let global = frontend.add_global_var(self.ctx, decl)?; + let expr = match global { + GlobalOrConstant::Global(handle) => Expression::GlobalVariable(handle), + GlobalOrConstant::Constant(handle) => Expression::Constant(handle), + }; + Ok(self.ctx.add_expression(expr, meta)?) + } + false => frontend.add_local_var(self.ctx, decl), + } + } +} |