Changeset - 5c3630dcfeb6
[Not reviewed]
0 3 0
mh - 4 years ago 2021-12-11 18:02:27
contact@maxhenger.nl
Add some tests for tuples, fix some initial bugs
3 files changed with 74 insertions and 4 deletions:
0 comments (0 inline, 0 general)
src/protocol/parser/pass_definitions_types.rs
Show inline comments
 
use crate::protocol::parser::*;
 
use crate::protocol::parser::token_parsing::*;
 

	
 
#[derive(Debug)]
 
struct Entry {
 
    element: ParserTypeElement,
 
    depth: i32,
 
}
 

	
 
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
 
enum DepthKind {
 
    Tuple, // because we had a `(` token
 
    PolyArgs, // because we had a `<` token
 
}
 

	
 
#[derive(Debug)]
 
struct DepthElement {
 
    kind: DepthKind,
 
    entry_index: u32, // in `entries` array of parser
 
    pos: InputPosition,
 
}
 

	
 
/// Current parsing state, for documentation's sake: types may be named, or may
 
/// be tuples. Named types may have polymorphic arguments (if the type
 
/// declaration allows) and a type may be turned into an array of that type by
 
/// postfixing a "[]".
 
#[derive(Debug)]
 
enum ParseState {
 
    TypeMaybePolyArgs,  // just parsed a type, might have poly arguments
 
    TypeNeverPolyArgs,  // just parsed a type that cannot have poly arguments
 
    PolyArgStart,       // just opened a polymorphic argument list
 
    TupleStart,         // just opened a tuple list
 
    ParsedComma,        // just had a comma
 
}
 

	
 
/// Parsers tokens into `ParserType` instances (yes, the name of the struct is
 
/// silly). Essentially a little state machine with its own temporary storage.
 
#[derive(Debug)]
 
pub(crate) struct ParserTypeParser {
 
    entries: Vec<Entry>,
 
    depths: Vec<DepthElement>,
 
    parse_state: ParseState,
 
    first_pos: InputPosition,
 
    last_pos: InputPosition,
 
}
 

	
 
impl ParserTypeParser {
 
    pub(crate) fn new() -> Self {
 
        return Self{
 
            entries: Vec::with_capacity(16),
 
            depths: Vec::with_capacity(16),
 
            parse_state: ParseState::TypeMaybePolyArgs,
 
            first_pos: InputPosition{ line: 0, offset: 0 },
 
            last_pos: InputPosition{ line: 0, offset: 0 }
 
        }
 
    }
 

	
 
    pub(crate) fn consume_parser_type(
 
        &mut self, iter: &mut TokenIter, heap: &Heap, source: &InputSource,
 
        symbols: &SymbolTable, poly_vars: &[Identifier],
 
        wrapping_definition: DefinitionId, cur_scope: SymbolScope,
 
        allow_inference: bool, inside_angular_bracket: Option<InputPosition>,
 
    ) -> Result<ParserType, ParseError> {
 
        // Prepare
 
        self.entries.clear();
 
        self.depths.clear();
 

	
 
        // Setup processing
 
        if let Some(bracket_pos) = inside_angular_bracket {
 
            self.push_depth(DepthKind::PolyArgs, u32::MAX, bracket_pos);
 
        }
 

	
 
        let initial_state = match iter.next() {
 
            Some(TokenKind::Ident) => {
 
                let element = Self::consume_parser_type_element(
 
                    iter, source, heap, symbols, wrapping_definition, poly_vars, cur_scope, allow_inference
 
                )?;
 
                self.first_pos = element.element_span.begin;
 
                self.last_pos = element.element_span.end;
 

	
 
                self.entries.push(Entry{
 
                    element,
 
                    depth: self.cur_depth(),
 
                });
 

	
 
                // Due to the nature of the subsequent type parsing algorithm,
 
                // we check the opening polymorphic argument list paren here.
 
                if let Some(TokenKind::OpenAngle) = iter.next() {
 
                    self.consume_open_angle(iter);
 
                    ParseState::PolyArgStart
 
                } else {
 
                    ParseState::TypeMaybePolyArgs
 
                }
 
            },
 
            Some(TokenKind::OpenParen) => {
 
                let tuple_start_pos = iter.next_start_position();
 
                self.first_pos = tuple_start_pos; // last pos will be set later, this is a tuple
 

	
 
                let tuple_entry_index = self.entries.len() as u32;
 
                let tuple_depth = self.cur_depth();
 
                self.push_depth(DepthKind::Tuple, tuple_entry_index, tuple_start_pos);
 
                self.entries.push(Entry{
 
                    element: ParserTypeElement{
 
                        element_span: InputSpan::from_positions(tuple_start_pos, tuple_start_pos),
 
                        variant: ParserTypeVariant::Tuple(0),
 
                    },
 
                    depth: self.cur_depth(),
 
                    depth: tuple_depth,
 
                });
 
                iter.consume();
 

	
 
                ParseState::PolyArgStart
 
                ParseState::TupleStart
 
            },
 
            _ => return Err(ParseError::new_error_str_at_pos(source, iter.last_valid_pos(), "expected a type")),
 
        };
 

	
 
        self.parse_state = initial_state;
 

	
 
        // Depth stack and entries are initialized, continue until depth stack
 
        // is empty, or until an unexpected set of tokens is encountered
 
        while !self.depths.is_empty() {
 
            let next = iter.next();
 

	
 
            match self.parse_state {
 
                ParseState::TypeMaybePolyArgs => {
 
                    // Allowed tokens: , < > >> ) [
 
                    match next {
 
                        Some(TokenKind::Comma) => self.consume_comma(iter),
 
                        Some(TokenKind::OpenAngle) => self.consume_open_angle(iter),
 
                        Some(TokenKind::CloseAngle) => self.consume_close_angle(source, iter)?,
 
                        Some(TokenKind::ShiftRight) => self.consume_double_close_angle(source, iter)?,
 
                        Some(TokenKind::CloseParen) => self.consume_close_paren(source, iter)?,
 
                        Some(TokenKind::OpenSquare) => self.consume_square_parens(source, iter)?,
 
                        _ => return Err(ParseError::new_error_str_at_pos(
 
                            source, iter.last_valid_pos(),
 
                            "unexpected token: expected ',', '<', '>', '<<', ')' or '['"
 
                        )),
 
                    }
 
                },
 
                ParseState::TypeNeverPolyArgs => {
 
                    // Allowed tokens: , > >> ) [
 
                    match next {
 
                        Some(TokenKind::Comma) => self.consume_comma(iter),
 
                        Some(TokenKind::CloseAngle) => self.consume_close_angle(source, iter)?,
 
                        Some(TokenKind::ShiftRight) => self.consume_double_close_angle(source, iter)?,
 
                        Some(TokenKind::CloseParen) => self.consume_close_paren(source, iter)?,
 
                        Some(TokenKind::OpenSquare) => self.consume_square_parens(source, iter)?,
 
                        _ => return Err(ParseError::new_error_str_at_pos(
 
                            source, iter.last_valid_pos(),
 
                            "unexpected token: expected ',', '>', '>>', ')' or '['"
 
                        )),
 
                    }
 
                },
 
                ParseState::PolyArgStart => {
 
                    // Allowed tokens: ident (
 
                    match next {
 
                        Some(TokenKind::Ident) => self.consume_type_idents(
 
                            source, heap, symbols, wrapping_definition, poly_vars, cur_scope, allow_inference, iter
 
                        )?,
 
                        Some(TokenKind::OpenParen) => self.consume_open_paren(iter),
 
                        _ => return Err(ParseError::new_error_str_at_pos(
 
                            source, iter.last_valid_pos(),
 
                            "unexpected token: expected typename or '('"
 
                        )),
 
                    }
 
                },
 
                ParseState::TupleStart => {
 
                    // Allowed tokens: ident )
 
                    match next {
 
                        Some(TokenKind::Ident) => self.consume_type_idents(
 
                            source, heap, symbols, wrapping_definition, poly_vars, cur_scope, allow_inference, iter
 
                        )?,
 
                        Some(TokenKind::CloseParen) => self.consume_close_paren(source, iter)?,
 
                        _ => return Err(ParseError::new_error_str_at_pos(
 
                            source, iter.last_valid_pos(),
 
                            "unexpected token: expected typename or ')'"
 
                        )),
 
                    }
 
                },
 
                ParseState::ParsedComma => {
 
                    // Allowed tokens: ident ( > >> )
 
                    match next {
 
                        Some(TokenKind::Ident) => self.consume_type_idents(
 
                            source, heap, symbols, wrapping_definition, poly_vars, cur_scope, allow_inference, iter
 
                        )?,
 
                        Some(TokenKind::OpenParen) => self.consume_open_paren(iter),
 
                        Some(TokenKind::CloseAngle) => self.consume_close_angle(source, iter)?,
 
                        Some(TokenKind::ShiftRight) => self.consume_double_close_angle(source, iter)?,
 
                        Some(TokenKind::CloseParen) => self.consume_close_paren(source, iter)?,
 
                        _ => return Err(ParseError::new_error_str_at_pos(
 
                            source, iter.last_valid_pos(),
 
                            "unexpected token: expected typename, '(', '>', '>>' or ')'"
 
                        ))
 
                    }
 
                }
 
            }
 
        }
 

	
 
        // If here then we have found the correct number of closing braces.
 
        // However we might still have any number of array postfixed
 
        if inside_angular_bracket.is_none() {
 
            while Some(TokenKind::OpenSquare) == iter.next() {
 
                self.consume_square_parens(source, iter)?;
 
            }
 
        }
 

	
 
        // Type should be completed. But we still need to check the polymorphic
 
        // arguments and strip tuples with just one embedded type.
 
        let num_entries = self.entries.len();
 

	
 
        for el_index in 0..num_entries {
 
            let cur_element = &self.entries[el_index];
 

	
 
            // Peek ahead to see how many embedded types we have
 
            let mut encountered_embedded = 0;
 
            for peek_index in el_index + 1..num_entries {
 
                let peek_element = &self.entries[peek_index];
 
                if peek_element.depth == cur_element.depth + 1 {
 
                    encountered_embedded += 1;
 
                } else if peek_element.depth <= cur_element.depth {
 
                    break;
 
                }
 
            }
 

	
 
            // If we're dealing with a tuple then we don't need to determine if
 
            // the number of embedded types is correct, we simply need to set it
 
            // to whatever what was encountered.
 
            if let ParserTypeVariant::Tuple(_) = cur_element.element.variant {
 
                self.entries[el_index].element.variant = ParserTypeVariant::Tuple(encountered_embedded);
 
            } else {
 
                let expected_embedded = cur_element.element.variant.num_embedded() as u32;
 
                if expected_embedded != encountered_embedded {
 
                    if encountered_embedded == 0 {
 
                        // Every polymorphic argument should be inferred
 
                        if !allow_inference {
 
                            println!("DEBUG: Ended up with {:?}", self.entries);
 
                            return Err(ParseError::new_error_str_at_span(
 
                                source, cur_element.element.element_span,
 
                                "type inference is not allowed here"
 
                            ));
 
                        }
 

	
 
                        // Insert missing types
 
                        let inserted_span = cur_element.element.element_span;
 
                        let inserted_depth = cur_element.depth + 1;
 
                        self.entries.reserve(expected_embedded as usize);
 
                        for _ in 0..expected_embedded {
 
                            self.entries.insert(el_index + 1, Entry {
 
                                element: ParserTypeElement {
 
                                    element_span: inserted_span,
 
                                    variant: ParserTypeVariant::Inferred,
 
                                },
 
                                depth: inserted_depth,
 
                            });
 
                        }
 
                    } else {
 
                        // Mismatch in number of embedded types
 
                        return Err(Self::construct_poly_arg_mismatch_error(
 
                            source, cur_element.element.element_span, allow_inference,
 
                            expected_embedded, encountered_embedded
 
                        ));
 
                    }
 
                }
 
            }
 
        }
 

	
 
        // Convert the results from parsing into the `ParserType`
 
        let mut elements = Vec::with_capacity(self.entries.len());
 
        debug_assert!(!self.entries.is_empty());
 

	
 
        for entry in self.entries.drain(..) {
 
            elements.push(entry.element)
 
            if ParserTypeVariant::Tuple(1) == entry.element.variant {
 
                // We strip these ones
 
            } else {
 
                elements.push(entry.element);
 
            }
 
        }
 

	
 
        return Ok(ParserType{
 
            elements,
 
            full_span: InputSpan::from_positions(self.first_pos, self.last_pos),
 
        });
 
    }
 

	
 
    // --- Parsing Utilities
 

	
 
    #[inline]
 
    fn consume_type_idents(
 
        &mut self, source: &InputSource, heap: &Heap, symbols: &SymbolTable,
 
        wrapping_definition: DefinitionId, poly_vars: &[Identifier],
 
        cur_scope: SymbolScope, allow_inference: bool, iter: &mut TokenIter
 
    ) -> Result<(), ParseError> {
 
        let element = Self::consume_parser_type_element(
 
            iter, source, heap, symbols, wrapping_definition, poly_vars, cur_scope, allow_inference
 
        )?;
 
        let depth = self.cur_depth();
 
        self.last_pos = element.element_span.end;
 
        self.entries.push(Entry{ element, depth });
 
        self.parse_state = ParseState::TypeMaybePolyArgs;
 

	
 
        return Ok(());
 
    }
 

	
 
    #[inline]
 
    fn consume_open_angle(&mut self, iter: &mut TokenIter) {
 
        // Note: open angular bracket is only consumed when we just parsed an
 
        //  ident-based type. So the last element of the `entries` array is the
 
        //  one that this angular bracket starts the polymorphic arguments for.
 
        let angle_start_pos = iter.next_start_position();
 
        let entry_index = (self.entries.len() - 1) as u32;
 
        self.push_depth(DepthKind::PolyArgs, entry_index, angle_start_pos);
 
        self.parse_state = ParseState::PolyArgStart;
 

	
 
        iter.consume();
 
    }
 

	
 
    #[inline]
 
    fn consume_close_angle(&mut self, source: &InputSource, iter: &mut TokenIter) -> Result<(), ParseError> {
 
        let (angle_start_pos, angle_end_pos) = iter.next_positions();
 
        self.last_pos = angle_end_pos;
 
        self.pop_depth(source, DepthKind::PolyArgs, angle_start_pos)?;
 
        self.parse_state = ParseState::TypeNeverPolyArgs;
 

	
 
        iter.consume();
 
        return Ok(())
 
    }
 

	
 
    #[inline]
 
    fn consume_double_close_angle(&mut self, source: &InputSource, iter: &mut TokenIter) -> Result<(), ParseError> {
 
        let (angle_start_pos, angle_end_pos) = iter.next_positions();
 
        self.last_pos = angle_end_pos;
 

	
 
        self.pop_depth(source, DepthKind::PolyArgs, angle_start_pos)?; // first '>' in '>>'.
 
        self.pop_depth(source, DepthKind::PolyArgs, angle_start_pos.with_offset(1))?; // second '>' in '>>'
 
        self.parse_state = ParseState::TypeNeverPolyArgs;
 

	
 
        iter.consume(); // consume once, '>>' is one token
 
        return Ok(())
 
    }
 

	
 
    #[inline]
 
    fn consume_open_paren(&mut self, iter: &mut TokenIter) {
 
        let paren_start_pos = iter.next_start_position();
 
        let cur_depth = self.cur_depth();
 
        let entry_index = self.entries.len() as u32;
 
        self.entries.push(Entry{
 
            element: ParserTypeElement {
 
                element_span: InputSpan::from_positions(paren_start_pos, paren_start_pos),
 
                variant: ParserTypeVariant::Tuple(0),
 
            },
 
            depth: cur_depth,
 
        });
 

	
 
        self.push_depth(DepthKind::Tuple, entry_index, paren_start_pos);
 
        self.parse_state = ParseState::TupleStart;
 

	
 
        iter.consume();
 
    }
 

	
 
    #[inline]
 
    fn consume_close_paren(&mut self, source: &InputSource, iter: &mut TokenIter) -> Result<(), ParseError> {
 
        let (paren_start_pos, paren_end_pos) = iter.next_positions();
 
        self.last_pos = paren_end_pos;
 
        let tuple_type_index = self.pop_depth(source, DepthKind::Tuple, paren_start_pos)?;
 
        self.entries[tuple_type_index as usize].element.element_span.end = paren_end_pos.with_offset(1);
 
        self.parse_state = ParseState::TypeNeverPolyArgs;
 

	
 
        iter.consume();
 
        return Ok(())
 
    }
 

	
 
    #[inline]
 
    fn consume_comma(&mut self, iter: &mut TokenIter) {
 
        iter.consume();
 
        self.parse_state = ParseState::ParsedComma;
 
    }
 

	
 
    #[inline]
 
    fn consume_square_parens(&mut self, source: &InputSource, iter: &mut TokenIter) -> Result<(), ParseError> {
 
        // Consume the opening square paren that forms the postfixed array type
 
        let array_start_pos = iter.next_start_position();
 
        iter.consume();
 
        if iter.next() != Some(TokenKind::CloseSquare) {
 
            return Err(ParseError::new_error_str_at_pos(
 
                source, iter.last_valid_pos(),
 
                "unexpected token: expected ']'"
 
            ));
 
        }
 

	
 
        let (_, array_end_pos) = iter.next_positions();
 
        let array_span = InputSpan::from_positions(array_start_pos, array_end_pos);
 
        self.last_pos = array_end_pos;
 
        iter.consume();
 

	
 
        // In the language we put the array specification after a type, in the
 
        // type tree we need to make the array type the parent, so:
 
        let insert_depth = self.cur_depth();
 
        let insert_at = self.entries.iter().rposition(|e| e.depth == insert_depth).unwrap();
 
        let num_embedded = self.entries[insert_at].element.variant.num_embedded();
 

	
 
        self.entries.insert(insert_at, Entry{
 
            element: ParserTypeElement{
 
                element_span: array_span,
 
                variant: ParserTypeVariant::Array,
 
            },
 
            depth: insert_depth
 
        });
 

	
 
        // Need to increment the depth of the child types
 
        self.entries[insert_at + 1].depth += 1; // element we applied the array type to
 
        if num_embedded != 0 {
 
            for index in insert_at + 2..self.entries.len() {
 
                let element = &mut self.entries[index];
 
                if element.depth >= insert_depth + 1 {
 
                    element.depth += 1;
 
                } else {
 
                    break;
 
                }
 
            }
 
        }
 

	
 
        return Ok(())
 
    }
 

	
 
    /// Consumes a namespaced identifier that should resolve to some kind of
 
    /// type. There may be commas or polymorphic arguments remaining after this
 
    /// function has finished.
 
    fn consume_parser_type_element(
 
        iter: &mut TokenIter, source: &InputSource, heap: &Heap, symbols: &SymbolTable,
 
        wrapping_definition: DefinitionId, poly_vars: &[Identifier],
 
        mut scope: SymbolScope, allow_inference: bool,
 
    ) -> Result<ParserTypeElement, ParseError> {
 
        use ParserTypeVariant as PTV;
 
        let (mut type_text, mut type_span) = consume_any_ident(source, iter)?;
 

	
 
        let variant = match type_text {
 
            KW_TYPE_MESSAGE => PTV::Message,
 
            KW_TYPE_BOOL => PTV::Bool,
 
            KW_TYPE_UINT8 => PTV::UInt8,
 
            KW_TYPE_UINT16 => PTV::UInt16,
 
            KW_TYPE_UINT32 => PTV::UInt32,
 
            KW_TYPE_UINT64 => PTV::UInt64,
 
            KW_TYPE_SINT8 => PTV::SInt8,
 
            KW_TYPE_SINT16 => PTV::SInt16,
 
            KW_TYPE_SINT32 => PTV::SInt32,
 
            KW_TYPE_SINT64 => PTV::SInt64,
 
            KW_TYPE_IN_PORT => PTV::Input,
 
            KW_TYPE_OUT_PORT => PTV::Output,
 
            KW_TYPE_CHAR => PTV::Character,
 
            KW_TYPE_STRING => PTV::String,
 
            KW_TYPE_INFERRED => {
 
                if !allow_inference {
 
                    return Err(ParseError::new_error_str_at_span(
 
                        source, type_span, "type inference is not allowed here"
 
                    ));
 
                }
 

	
 
                PTV::Inferred
 
            },
 
            _ => {
 
                // Must be some kind of symbolic type
 
                let mut type_kind = None;
 
                for (poly_idx, poly_var) in poly_vars.iter().enumerate() {
 
                    if poly_var.value.as_bytes() == type_text {
 
                        type_kind = Some(PTV::PolymorphicArgument(wrapping_definition, poly_idx as u32));
 
                    }
 
                }
 

	
 
                if type_kind.is_none() {
 
                    // Check symbol table for definition. To be fair, the language
 
                    // only allows a single namespace for now. That said:
 
                    let last_symbol = symbols.get_symbol_by_name(scope, type_text);
 
                    if last_symbol.is_none() {
 
                        return Err(ParseError::new_error_str_at_span(
 
                            source, type_span, "unknown type"
 
                        ));
 
                    }
 
                    let mut last_symbol = last_symbol.unwrap();
 

	
 
                    // Resolving scopes until we reach the intended type
 
                    loop {
 
                        match &last_symbol.variant {
 
                            SymbolVariant::Module(symbol_module) => {
 
                                // Expecting more identifiers
 
                                if Some(TokenKind::ColonColon) != iter.next() {
 
                                    return Err(ParseError::new_error_str_at_span(
 
                                        source, type_span, "expected a type but got a module"
 
                                    ));
 
                                }
 

	
 
                                consume_token(source, iter, TokenKind::ColonColon)?;
 

	
 
                                // Consume next part of type and prepare for next
 
                                // lookup loop
 
                                let (next_text, next_span) = consume_any_ident(source, iter)?;
 
                                let old_text = type_text;
 
                                type_text = next_text;
 
                                type_span.end = next_span.end;
 
                                scope = SymbolScope::Module(symbol_module.root_id);
 

	
 
                                let new_symbol = symbols.get_symbol_by_name_defined_in_scope(scope, type_text);
 
                                if new_symbol.is_none() {
 
                                    // If the type is imported in the module then notify the programmer
 
                                    // that imports do not leak outside of a module
 
                                    let type_name = String::from_utf8_lossy(type_text);
 
                                    let module_name = String::from_utf8_lossy(old_text);
 
                                    let suffix = if symbols.get_symbol_by_name(scope, type_text).is_some() {
 
                                        format!(
 
                                            ". The module '{}' does import '{}', but these imports are not visible to other modules",
 
                                            &module_name, &type_name
 
                                        )
 
                                    } else {
 
                                        String::new()
 
                                    };
 

	
 
                                    let message = format!("unknown type '{}' in module '{}'{}", type_name, module_name, suffix);
 
                                    return Err(ParseError::new_error_at_span(source, next_span, message));
 
                                }
 

	
 
                                last_symbol = new_symbol.unwrap();
 
                            },
 
                            SymbolVariant::Definition(symbol_definition) => {
 
                                let num_poly_vars = heap[symbol_definition.definition_id].poly_vars().len();
 
                                type_kind = Some(PTV::Definition(symbol_definition.definition_id, num_poly_vars as u32));
 
                                break;
 
                            }
 
                        }
 
                    }
 
                }
 

	
 
                debug_assert!(type_kind.is_some());
 
                type_kind.unwrap()
 
            },
 
        };
 

	
 
        Ok(ParserTypeElement{ element_span: type_span, variant })
 
    }
 

	
 
    // --- Parsing Depth Management
 

	
 
    #[inline]
 
    fn push_depth(&mut self, kind: DepthKind, entry_index: u32, pos: InputPosition) {
 
        self.depths.push(DepthElement{ kind, entry_index, pos });
 
    }
 

	
 
    #[inline]
 
    fn pop_depth(&mut self, source: &InputSource, kind: DepthKind, pos: InputPosition) -> Result<u32, ParseError> {
 
        if self.depths.is_empty() {
 
            // More closing parens than opening ones
 
            let message = match kind {
 
                DepthKind::Tuple => "unmatched ')'",
 
                DepthKind::PolyArgs => "unmatched '>'",
 
            };
 
            return Err(ParseError::new_error_str_at_pos(source, pos, message))
 
        }
 

	
 
        let last = self.depths.last().unwrap();
 
        if last.kind != kind {
 
            // Wrong kind of closing parens
 
            let (encountered_message, matching_message) = match kind {
 
                DepthKind::Tuple => (
 
                    "unexpected closing ')'",
 
                    "expected a '>' to match this '<'"
 
                ),
 
                DepthKind::PolyArgs => (
 
                    "unexpected closing '>'",
 
                    "expected a ')' to match this '('"
 
                ),
 
            };
 

	
 
            return Err(
 
                ParseError::new_error_str_at_pos(source, pos, encountered_message)
 
                    .with_info_str_at_pos(source, last.pos, matching_message)
 
            );
 
        }
 

	
 
        let popped = self.depths.pop().unwrap();
 
        return Ok(popped.entry_index);
 
    }
 

	
 
    #[inline]
 
    fn cur_depth(&self) -> i32 {
 
        return self.depths.len() as i32;
 
    }
 

	
 
    // --- Small Utilities
 

	
 
    fn construct_poly_arg_mismatch_error(
 
        source: &InputSource, span: InputSpan, allow_inference: bool,
 
        num_expected: u32, num_encountered: u32
 
    ) -> ParseError {
 
        let type_name = String::from_utf8_lossy(source.section_at_span(span));
 

	
 
        fn polymorphic_name_text(num: u32) -> &'static str {
 
            if num == 1 { "polymorphic argument" } else { "polymorphic arguments" }
 
        }
 
        fn were_or_was(num: u32) -> &'static str {
 
            if num == 1 { "was" } else { "were" }
 
        }
 

	
 
        if num_expected == 0 {
 
            return ParseError::new_error_at_span(
 
                source, span,
 
                format!(
 
                    "the type '{}' is not polymorphic, yet {} {} {} provided",
 
                    type_name, num_encountered, polymorphic_name_text(num_encountered),
 
                    were_or_was(num_encountered)
 
                )
 
            );
 
        }
 

	
 
        let maybe_infer_text = if allow_inference {
 
            " (or none, to perform implicit type inference)"
 
        } else {
 
            ""
 
        };
 

	
 
        return ParseError::new_error_at_span(
 
            source, span,
 
            format!(
 
                "expected {} {}{} for the type '{}', but {} {} provided",
 
                num_expected, polymorphic_name_text(num_expected),
 
                maybe_infer_text, type_name, num_encountered,
 
                were_or_was(num_encountered)
 
            )
 
        );
 
    }
 
}
 
\ No newline at end of file
src/protocol/parser/type_table.rs
Show inline comments
 
/**
 
 * type_table.rs
 
 *
 
 * The type table is a lookup from AST definition (which contains just what the
 
 * programmer typed) to a type with additional information computed (e.g. the
 
 * byte size and offsets of struct members). The type table should be considered
 
 * the authoritative source of information on types by the compiler (not the
 
 * AST itself!).
 
 *
 
 * The type table operates in two modes: one is where we just look up the type,
 
 * check its fields for correctness and mark whether it is polymorphic or not.
 
 * The second one is where we compute byte sizes, alignment and offsets.
 
 *
 
 * The basic algorithm for type resolving and computing byte sizes is to
 
 * recursively try to lay out each member type of a particular type. This is
 
 * done in a stack-like fashion, where each embedded type pushes a breadcrumb
 
 * unto the stack. We may discover a cycle in embedded types (we call this a
 
 * "type loop"). After which the type table attempts to break the type loop by
 
 * making specific types heap-allocated. Upon doing so we know their size
 
 * because their stack-size is now based on pointers. Hence breaking the type
 
 * loop required for computing the byte size of types.
 
 *
 
 * The reason for these type shenanigans is because PDL is a value-based
 
 * language, but we would still like to be able to express recursively defined
 
 * types like trees or linked lists. Hence we need to insert pointers somewhere
 
 * to break these cycles.
 
 *
 
 * We will insert these pointers into the variants of unions. However note that
 
 * we can only compute the stack size of a union until we've looked at *all*
 
 * variants. Hence we perform an initial pass where we detect type loops, a
 
 * second pass where we compute the stack sizes of everything, and a third pass
 
 * where we actually compute the size of the heap allocations for unions.
 
 *
 
 * As a final bit of global documentation: non-polymorphic types will always
 
 * have one "monomorph" entry. This contains the non-polymorphic type's memory
 
 * layout.
 
 */
 

	
 
use std::fmt::{Formatter, Result as FmtResult};
 
use std::collections::HashMap;
 

	
 
use crate::protocol::ast::*;
 
use crate::protocol::parser::symbol_table::SymbolScope;
 
use crate::protocol::input_source::ParseError;
 
use crate::protocol::parser::*;
 

	
 
//------------------------------------------------------------------------------
 
// Defined Types
 
//------------------------------------------------------------------------------
 

	
 
#[derive(Copy, Clone, PartialEq, Eq)]
 
pub enum TypeClass {
 
    Enum,
 
    Union,
 
    Struct,
 
    Function,
 
    Component
 
}
 

	
 
impl TypeClass {
 
    pub(crate) fn display_name(&self) -> &'static str {
 
        match self {
 
            TypeClass::Enum => "enum",
 
            TypeClass::Union => "union",
 
            TypeClass::Struct => "struct",
 
            TypeClass::Function => "function",
 
            TypeClass::Component => "component",
 
        }
 
    }
 

	
 
    pub(crate) fn is_data_type(&self) -> bool {
 
        match self {
 
            TypeClass::Enum | TypeClass::Union | TypeClass::Struct => true,
 
            TypeClass::Function | TypeClass::Component => false,
 
        }
 
    }
 
}
 

	
 
impl std::fmt::Display for TypeClass {
 
    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
 
        write!(f, "{}", self.display_name())
 
    }
 
}
 

	
 
/// Struct wrapping around a potentially polymorphic type. If the type does not
 
/// have any polymorphic arguments then it will not have any monomorphs and
 
/// `is_polymorph` will be set to `false`. A type with polymorphic arguments
 
/// only has `is_polymorph` set to `true` if the polymorphic arguments actually
 
/// appear in the types associated types (function return argument, struct
 
/// field, enum variant, etc.). Otherwise the polymorphic argument is just a
 
/// marker and does not influence the bytesize of the type.
 
pub struct DefinedType {
 
    pub(crate) ast_root: RootId,
 
    pub(crate) ast_definition: DefinitionId,
 
    pub(crate) definition: DefinedTypeVariant,
 
    pub(crate) poly_vars: Vec<PolymorphicVariable>,
 
    pub(crate) is_polymorph: bool,
 
}
 

	
 
impl DefinedType {
 
    /// Returns the number of monomorphs that are instantiated. Remember that
 
    /// during the type loop detection, and the memory layout phase we will
 
    /// pre-allocate monomorphs which are not yet fully laid out in memory.
 
    pub(crate) fn num_monomorphs(&self) -> usize {
 
        use DefinedTypeVariant as DTV;
 
        match &self.definition {
 
            DTV::Enum(def) => def.monomorphs.len(),
 
            DTV::Union(def) => def.monomorphs.len(),
 
            DTV::Struct(def) => def.monomorphs.len(),
 
            DTV::Function(_) | DTV::Component(_) => unreachable!(),
 
        }
 
    }
 

	
 
    /// Returns the index at which a monomorph occurs. Will only check the
 
    /// polymorphic arguments that are in use (none of the, in rust lingo,
 
    /// phantom types). If the type is not polymorphic and its memory has been
 
    /// layed out, then this will always return `Some(0)`.
 
    pub(crate) fn get_monomorph_index(&self, parts: &[ConcreteTypePart]) -> Option<usize> {
 
        use DefinedTypeVariant as DTV;
 

	
 
        // Helper to compare two types, while disregarding the polymorphic
 
        // variables that are not in use.
 
        let concrete_types_match = |type_a: &[ConcreteTypePart], type_b: &[ConcreteTypePart], check_if_poly_var_is_used: bool| -> bool {
 
            let mut a_iter = ConcreteTypeIter::new(type_a, 0).enumerate();
 
            let mut b_iter = ConcreteTypeIter::new(type_b, 0);
 

	
 
            while let Some((section_idx, a_section)) = a_iter.next() {
 
                let b_section = b_iter.next().unwrap();
 

	
 
                if check_if_poly_var_is_used && !self.poly_vars[section_idx].is_in_use {
 
                    continue;
 
                }
 

	
 
                if a_section != b_section {
 
                    return false;
 
                }
 
            }
 

	
 
            return true;
 
        };
 

	
 
        // Check check if type is polymorphic to some degree at all
 
        if cfg!(debug_assertions) {
 
            if let ConcreteTypePart::Instance(definition_id, num_poly_args) = parts[0] {
 
                assert_eq!(definition_id, self.ast_definition);
 
                assert_eq!(num_poly_args as usize, self.poly_vars.len());
 
            } else {
 
                assert!(false, "concrete type {:?} is not a user-defined type", parts);
 
            }
 
        }
 

	
 
        match &self.definition {
 
            DTV::Enum(definition) => {
 
                // Special case, enum is never a "true polymorph"
 
                debug_assert!(!self.is_polymorph);
 
                if definition.monomorphs.is_empty() {
 
                    return None
 
                } else {
 
                    return Some(0)
 
                }
 
            },
 
            DTV::Union(definition) => {
 
                for (monomorph_idx, monomorph) in definition.monomorphs.iter().enumerate() {
 
                    if concrete_types_match(&monomorph.concrete_type.parts, parts, true) {
 
                        return Some(monomorph_idx);
 
                    }
 
                }
 
            },
 
            DTV::Struct(definition) => {
 
                for (monomorph_idx, monomorph) in definition.monomorphs.iter().enumerate() {
 
                    if concrete_types_match(&monomorph.concrete_type.parts, parts, true) {
 
                        return Some(monomorph_idx);
 
                    }
 
                }
 
            },
 
            DTV::Function(definition) => {
 
                for (monomorph_idx, monomorph) in definition.monomorphs.iter().enumerate() {
 
                    if concrete_types_match(&monomorph.concrete_type.parts, parts, false) {
 
                        return Some(monomorph_idx)
 
                    }
 
                }
 
            }
 
            DTV::Component(definition) => {
 
                for (monomorph_idx, monomorph) in definition.monomorphs.iter().enumerate() {
 
                    if concrete_types_match(&monomorph.concrete_type.parts, parts, false) {
 
                        return Some(monomorph_idx)
 
                    }
 
                }
 
            }
 
        }
 

	
 
        // Nothing matched
 
        return None;
 
    }
 

	
 
    /// Retrieves size and alignment of the particular type's monomorph if it
 
    /// has been layed out in memory.
 
    pub(crate) fn get_monomorph_size_alignment(&self, idx: usize) -> Option<(usize, usize)> {
 
        use DefinedTypeVariant as DTV;
 
        let (size, alignment) = match &self.definition {
 
            DTV::Enum(def) => {
 
                debug_assert!(idx == 0);
 
                (def.size, def.alignment)
 
            },
 
            DTV::Union(def) => {
 
                let monomorph = &def.monomorphs[idx];
 
                (monomorph.stack_size, monomorph.stack_alignment)
 
            },
 
            DTV::Struct(def) => {
 
                let monomorph = &def.monomorphs[idx];
 
                (monomorph.size, monomorph.alignment)
 
            },
 
            DTV::Function(_) | DTV::Component(_) => {
 
                // Type table should never be able to arrive here during layout
 
                // of types. Types may only contain function prototypes.
 
                unreachable!("retrieving size and alignment of procedure type");
 
            }
 
        };
 

	
 
        if size == 0 && alignment == 0 {
 
            // The "marker" for when the type has not been layed out yet. Even
 
            // for zero-size types we will set alignment to `1` to simplify
 
            // alignment calculations.
 
            return None;
 
        } else {
 
            return Some((size, alignment));
 
        }
 
    }
 
}
 

	
 
pub enum DefinedTypeVariant {
 
    Enum(EnumType),
 
    Union(UnionType),
 
    Struct(StructType),
 
    Function(FunctionType),
 
    Component(ComponentType)
 
}
 

	
 
impl DefinedTypeVariant {
 
    pub(crate) fn type_class(&self) -> TypeClass {
 
        match self {
 
            DefinedTypeVariant::Enum(_) => TypeClass::Enum,
 
            DefinedTypeVariant::Union(_) => TypeClass::Union,
 
            DefinedTypeVariant::Struct(_) => TypeClass::Struct,
 
            DefinedTypeVariant::Function(_) => TypeClass::Function,
 
            DefinedTypeVariant::Component(_) => TypeClass::Component
 
        }
 
    }
 

	
 
    pub(crate) fn as_struct(&self) -> &StructType {
 
        match self {
 
            DefinedTypeVariant::Struct(v) => v,
 
            _ => unreachable!("Cannot convert {} to struct variant", self.type_class())
 
        }
 
    }
 

	
 
    pub(crate) fn as_struct_mut(&mut self) -> &mut StructType {
 
        match self {
 
            DefinedTypeVariant::Struct(v) => v,
 
            _ => unreachable!("Cannot convert {} to struct variant", self.type_class())
 
        }
 
    }
 

	
 
    pub(crate) fn as_enum(&self) -> &EnumType {
 
        match self {
 
            DefinedTypeVariant::Enum(v) => v,
 
            _ => unreachable!("Cannot convert {} to enum variant", self.type_class())
 
        }
 
    }
 

	
 
    pub(crate) fn as_enum_mut(&mut self) -> &mut EnumType {
 
        match self {
 
            DefinedTypeVariant::Enum(v) => v,
 
            _ => unreachable!("Cannot convert {} to enum variant", self.type_class())
 
        }
 
    }
 

	
 
    pub(crate) fn as_union(&self) -> &UnionType {
 
        match self {
 
            DefinedTypeVariant::Union(v) => v,
 
            _ => unreachable!("Cannot convert {} to union variant", self.type_class())
 
        }
 
    }
 

	
 
    pub(crate) fn as_union_mut(&mut self) -> &mut UnionType {
 
        match self {
 
            DefinedTypeVariant::Union(v) => v,
 
            _ => unreachable!("Cannot convert {} to union variant", self.type_class())
 
        }
 
    }
 

	
 
    pub(crate) fn procedure_monomorphs(&self) -> &Vec<ProcedureMonomorph> {
 
        use DefinedTypeVariant::*;
 

	
 
        match self {
 
            Function(v) => &v.monomorphs,
 
            Component(v) => &v.monomorphs,
 
            _ => unreachable!("cannot get procedure monomorphs from {}", self.type_class()),
 
        }
 
    }
 

	
 
    pub(crate) fn procedure_monomorphs_mut(&mut self) -> &mut Vec<ProcedureMonomorph> {
 
        use DefinedTypeVariant::*;
 

	
 
        match self {
 
            Function(v) => &mut v.monomorphs,
 
            Component(v) => &mut v.monomorphs,
 
            _ => unreachable!("cannot get procedure monomorphs from {}", self.type_class()),
 
        }
 
    }
 
}
 

	
 
pub struct PolymorphicVariable {
 
    identifier: Identifier,
 
    is_in_use: bool, // a polymorphic argument may be defined, but not used by the type definition
 
}
 

	
 
/// Data associated with a monomorphized procedure type. Has the wrong name,
 
/// because it will also be used to store expression data for a non-polymorphic
 
/// procedure. (in that case, there will only ever be one)
 
pub struct ProcedureMonomorph {
 
    // Expression data for one particular monomorph
 
    pub concrete_type: ConcreteType,
 
    pub arg_types: Vec<ConcreteType>,
 
    pub expr_data: Vec<MonomorphExpression>,
 
}
 

	
 
/// `EnumType` is the classical C/C++ enum type. It has various variants with
 
/// an assigned integer value. The integer values may be user-defined,
 
/// compiler-defined, or a mix of the two. If a user assigns the same enum
 
/// value multiple times, we assume the user is an expert and we consider both
 
/// variants to be equal to one another.
 
pub struct EnumType {
 
    pub variants: Vec<EnumVariant>,
 
    pub monomorphs: Vec<EnumMonomorph>,
 
    pub minimum_tag_value: i64,
 
    pub maximum_tag_value: i64,
 
    pub tag_type: ConcreteType,
 
    pub size: usize,
 
    pub alignment: usize,
 
}
 

	
 
// TODO: Also support maximum u64 value
 
pub struct EnumVariant {
 
    pub identifier: Identifier,
 
    pub value: i64,
 
}
 

	
 
pub struct EnumMonomorph {
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
/// `UnionType` is the algebraic datatype (or sum type, or discriminated union).
 
/// A value is an element of the union, identified by its tag, and may contain
 
/// a single subtype.
 
/// For potentially infinite types (i.e. a tree, or a linked list) only unions
 
/// can break the infinite cycle. So when we lay out these unions in memory we
 
/// will reserve enough space on the stack for all union variants that do not
 
/// cause "type loops" (i.e. a union `A` with a variant containing a struct
 
/// `B`). And we will reserve enough space on the heap (and store a pointer in
 
/// the union) for all variants which do cause type loops (i.e. a union `A`
 
/// with a variant to a struct `B` that contains the union `A` again).
 
pub struct UnionType {
 
    pub variants: Vec<UnionVariant>,
 
    pub monomorphs: Vec<UnionMonomorph>,
 
    pub tag_type: ConcreteType,
 
    pub tag_size: usize,
 
}
 

	
 
pub struct UnionVariant {
 
    pub identifier: Identifier,
 
    pub embedded: Vec<ParserType>, // zero-length does not have embedded values
 
    pub tag_value: i64,
 
}
 

	
 
pub struct UnionMonomorph {
 
    pub concrete_type: ConcreteType,
 
    pub variants: Vec<UnionMonomorphVariant>,
 
    // stack_size is the size of the union on the stack, includes the tag
 
    pub stack_size: usize,
 
    pub stack_alignment: usize,
 
    // heap_size contains the allocated size of the union in the case it
 
    // is used to break a type loop. If it is 0, then it doesn't require
 
    // allocation and lives entirely on the stack.
 
    pub heap_size: usize,
 
    pub heap_alignment: usize,
 
}
 

	
 
pub struct UnionMonomorphVariant {
 
    pub lives_on_heap: bool,
 
    pub embedded: Vec<UnionMonomorphEmbedded>,
 
}
 

	
 
pub struct UnionMonomorphEmbedded {
 
    pub concrete_type: ConcreteType,
 
    // Note that the meaning of the offset (and alignment) depend on whether or
 
    // not the variant lives on the stack/heap. If it lives on the stack then
 
    // they refer to the offset from the start of the union value (so the first
 
    // embedded type lives at a non-zero offset, because the union tag sits in
 
    // the front). If it lives on the heap then it refers to the offset from the
 
    // allocated memory region (so the first embedded type lives at a 0 offset).
 
    pub size: usize,
 
    pub alignment: usize,
 
    pub offset: usize,
 
}
 

	
 
/// `StructType` is a generic C-like struct type (or record type, or product
 
/// type) type.
 
pub struct StructType {
 
    pub fields: Vec<StructField>,
 
    pub monomorphs: Vec<StructMonomorph>,
 
}
 

	
 
pub struct StructField {
 
    pub identifier: Identifier,
 
    pub parser_type: ParserType,
 
}
 

	
 
pub struct StructMonomorph {
 
    pub concrete_type: ConcreteType,
 
    pub fields: Vec<StructMonomorphField>,
 
    pub size: usize,
 
    pub alignment: usize,
 
}
 

	
 
pub struct StructMonomorphField {
 
    pub concrete_type: ConcreteType,
 
    pub size: usize,
 
    pub alignment: usize,
 
    pub offset: usize,
 
}
 

	
 
/// `FunctionType` is what you expect it to be: a particular function's
 
/// signature.
 
pub struct FunctionType {
 
    pub return_types: Vec<ParserType>,
 
    pub arguments: Vec<FunctionArgument>,
 
    pub monomorphs: Vec<ProcedureMonomorph>,
 
}
 

	
 
pub struct ComponentType {
 
    pub variant: ComponentVariant,
 
    pub arguments: Vec<FunctionArgument>,
 
    pub monomorphs: Vec<ProcedureMonomorph>
 
}
 

	
 
pub struct FunctionArgument {
 
    identifier: Identifier,
 
    parser_type: ParserType,
 
}
 

	
 
/// Represents the data associated with a single expression after type inference
 
/// for a monomorph (or just the normal expression types, if dealing with a
 
/// non-polymorphic function/component).
 
pub struct MonomorphExpression {
 
    // The output type of the expression. Note that for a function it is not the
 
    // function's signature but its return type
 
    pub(crate) expr_type: ConcreteType,
 
    // Has multiple meanings: the field index for select expressions, the
 
    // monomorph index for polymorphic function calls or literals. Negative
 
    // values are never used, but used to catch programming errors.
 
    pub(crate) field_or_monomorph_idx: i32,
 
}
 

	
 
//------------------------------------------------------------------------------
 
// Type table
 
//------------------------------------------------------------------------------
 

	
 
// Programmer note: keep this struct free of dynamically allocated memory
 
#[derive(Clone)]
 
struct TypeLoopBreadcrumb {
 
    definition_id: DefinitionId,
 
    monomorph_idx: usize,
 
    next_member: usize,
 
    next_embedded: usize, // for unions, the index into the variant's embedded types
 
}
 

	
 
#[derive(Clone)]
 
struct MemoryBreadcrumb {
 
    definition_id: DefinitionId,
 
    monomorph_idx: usize,
 
    next_member: usize,
 
    next_embedded: usize,
 
    first_size_alignment_idx: usize,
 
}
 

	
 
#[derive(Debug, PartialEq, Eq)]
 
enum TypeLoopResult {
 
    TypeExists,
 
    PushBreadcrumb(DefinitionId, ConcreteType),
 
    TypeLoop(usize), // index into vec of breadcrumbs at which the type matched
 
}
 

	
 
enum MemoryLayoutResult {
 
    TypeExists(usize, usize), // (size, alignment)
 
    PushBreadcrumb(MemoryBreadcrumb),
 
}
 

	
 
// TODO: @Optimize, initial memory-unoptimized implementation
 
struct TypeLoopEntry {
 
    definition_id: DefinitionId,
 
    monomorph_idx: usize,
 
    is_union: bool,
 
}
 

	
 
struct TypeLoop {
 
    members: Vec<TypeLoopEntry>
 
}
 

	
 
pub struct TypeTable {
 
    /// Lookup from AST DefinitionId to a defined type. Considering possible
 
    /// polymorphs is done inside the `DefinedType` struct.
 
    lookup: HashMap<DefinitionId, DefinedType>,
 
    /// Breadcrumbs left behind while trying to find type loops. Also used to
 
    /// determine sizes of types when all type loops are detected.
 
    type_loop_breadcrumbs: Vec<TypeLoopBreadcrumb>,
 
    type_loops: Vec<TypeLoop>,
 
    /// Stores all encountered types during type loop detection. Used afterwards
 
    /// to iterate over all types in order to compute size/alignment.
 
    encountered_types: Vec<TypeLoopEntry>,
 
    /// Breadcrumbs and temporary storage during memory layout computation.
 
    memory_layout_breadcrumbs: Vec<MemoryBreadcrumb>,
 
    size_alignment_stack: Vec<(usize, usize)>,
 
}
 

	
 
impl TypeTable {
 
    /// Construct a new type table without any resolved types.
 
    pub(crate) fn new() -> Self {
 
        Self{ 
 
            lookup: HashMap::new(), 
 
            type_loop_breadcrumbs: Vec::with_capacity(32),
 
            type_loops: Vec::with_capacity(8),
 
            encountered_types: Vec::with_capacity(32),
 
            memory_layout_breadcrumbs: Vec::with_capacity(32),
 
            size_alignment_stack: Vec::with_capacity(64),
 
        }
 
    }
 

	
 
    /// Iterates over all defined types (polymorphic and non-polymorphic) and
 
    /// add their types in two passes. In the first pass we will just add the
 
    /// base types (we will not consider monomorphs, and we will not compute
 
    /// byte sizes). In the second pass we will compute byte sizes of
 
    /// non-polymorphic types, and potentially the monomorphs that are embedded
 
    /// in those types.
 
    pub(crate) fn build_base_types(&mut self, modules: &mut [Module], ctx: &mut PassCtx) -> Result<(), ParseError> {
 
        // Make sure we're allowed to cast root_id to index into ctx.modules
 
        debug_assert!(modules.iter().all(|m| m.phase >= ModuleCompilationPhase::DefinitionsParsed));
 
        debug_assert!(self.lookup.is_empty());
 

	
 
        if cfg!(debug_assertions) {
 
            for (index, module) in modules.iter().enumerate() {
 
                debug_assert_eq!(index, module.root_id.index as usize);
 
            }
 
        }
 

	
 
        // Use context to guess hashmap size of the base types
 
        let reserve_size = ctx.heap.definitions.len();
 
        self.lookup.reserve(reserve_size);
 

	
 
        // Resolve all base types
 
        for definition_idx in 0..ctx.heap.definitions.len() {
 
            let definition_id = ctx.heap.definitions.get_id(definition_idx);
 
            let definition = &ctx.heap[definition_id];
 

	
 
            match definition {
 
                Definition::Enum(_) => self.build_base_enum_definition(modules, ctx, definition_id)?,
 
                Definition::Union(_) => self.build_base_union_definition(modules, ctx, definition_id)?,
 
                Definition::Struct(_) => self.build_base_struct_definition(modules, ctx, definition_id)?,
 
                Definition::Function(_) => self.build_base_function_definition(modules, ctx, definition_id)?,
 
                Definition::Component(_) => self.build_base_component_definition(modules, ctx, definition_id)?,
 
            }
 
        }
 

	
 
        debug_assert_eq!(self.lookup.len(), reserve_size, "mismatch in reserved size of type table"); // NOTE: Temp fix for builtin functions
 
        for module in modules.iter_mut() {
 
            module.phase = ModuleCompilationPhase::TypesAddedToTable;
 
        }
 

	
 
        // Go through all types again, lay out all types that are not
 
        // polymorphic. This might cause us to lay out types that are monomorphs
 
        // of polymorphic types.
 
        for definition_idx in 0..ctx.heap.definitions.len() {
 
            let definition_id = ctx.heap.definitions.get_id(definition_idx);
 
            let poly_type = self.lookup.get(&definition_id).unwrap();
 

	
 
            // Here we explicitly want to instantiate types which have no
 
            // polymorphic arguments (even if it has phantom polymorphic
 
            // arguments) because otherwise the user will see very weird
 
            // error messages.
 
            if poly_type.definition.type_class().is_data_type() && poly_type.poly_vars.is_empty() && poly_type.num_monomorphs() == 0 {
 
                self.detect_and_resolve_type_loops_for(
 
                    modules, ctx.heap,
 
                    ConcreteType{
 
                        parts: vec![ConcreteTypePart::Instance(definition_id, 0)]
 
                    },
 
                )?;
 
                self.lay_out_memory_for_encountered_types(ctx.arch);
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    /// Retrieves base definition from type table. We must be able to retrieve
 
    /// it as we resolve all base types upon type table construction (for now).
 
    /// However, in the future we might do on-demand type resolving, so return
 
    /// an option anyway
 
    pub(crate) fn get_base_definition(&self, definition_id: &DefinitionId) -> Option<&DefinedType> {
 
        self.lookup.get(&definition_id)
 
    }
 

	
 
    /// Returns the index into the monomorph type array if the procedure type
 
    /// already has a (reserved) monomorph.
 
    pub(crate) fn get_procedure_monomorph_index(&self, definition_id: &DefinitionId, types: &ConcreteType) -> Option<i32> {
 
        let def = self.lookup.get(definition_id).unwrap();
 
        let monos = def.definition.procedure_monomorphs();
 
        return monos.iter()
 
            .position(|v| v.concrete_type == *types)
 
            .map(|v| v as i32);
 
    }
 

	
 
    /// Returns a mutable reference to a procedure's monomorph expression data.
 
    /// Used by typechecker to fill in previously reserved type information
 
    pub(crate) fn get_procedure_expression_data_mut(&mut self, definition_id: &DefinitionId, monomorph_idx: i32) -> &mut ProcedureMonomorph {
 
        debug_assert!(monomorph_idx >= 0);
 
        let def = self.lookup.get_mut(definition_id).unwrap();
 
        let monomorphs = def.definition.procedure_monomorphs_mut();
 
        return &mut monomorphs[monomorph_idx as usize];
 
    }
 

	
 
    pub(crate) fn get_procedure_expression_data(&self, definition_id: &DefinitionId, monomorph_idx: i32) -> &ProcedureMonomorph {
 
        debug_assert!(monomorph_idx >= 0);
 
        let def = self.lookup.get(definition_id).unwrap();
 
        let monomorphs = def.definition.procedure_monomorphs();
 
        return &monomorphs[monomorph_idx as usize];
 
    }
 

	
 
    /// Reserves space for a monomorph of a polymorphic procedure. The index
 
    /// will point into a (reserved) slot of the array of expression types. The
 
    /// monomorph may NOT exist yet (because the reservation implies that we're
 
    /// going to be performing typechecking on it, and we don't want to
 
    /// check the same monomorph twice)
 
    pub(crate) fn reserve_procedure_monomorph_index(&mut self, definition_id: &DefinitionId, concrete_type: ConcreteType) -> i32 {
 
        let def = self.lookup.get_mut(definition_id).unwrap();
 
        let mono_types = def.definition.procedure_monomorphs_mut();
 
        debug_assert!(def.is_polymorph == (concrete_type.parts.len() != 1));
 
        debug_assert!(!mono_types.iter().any(|v| v.concrete_type == concrete_type));
 

	
 
        let mono_idx = mono_types.len();
 
        mono_types.push(ProcedureMonomorph{
 
            concrete_type,
 
            arg_types: Vec::new(),
 
            expr_data: Vec::new(),
 
        });
 

	
 
        return mono_idx as i32;
 
    }
 

	
 
    /// Adds a datatype polymorph to the type table. Will not add the
 
    /// monomorph if it is already present, or if the type's polymorphic
 
    /// variables are all unused.
 
    /// TODO: Fix signature
 
    pub(crate) fn add_data_monomorph(
 
        &mut self, modules: &[Module], heap: &Heap, arch: &TargetArch, definition_id: DefinitionId, concrete_type: ConcreteType
 
    ) -> Result<i32, ParseError> {
 
        debug_assert_eq!(definition_id, get_concrete_type_definition(&concrete_type));
 

	
 
        // Check if the monomorph already exists
 
        let poly_type = self.lookup.get_mut(&definition_id).unwrap();
 
        if let Some(idx) = poly_type.get_monomorph_index(&concrete_type.parts) {
 
            return Ok(idx as i32);
 
        }
 

	
 
        // Doesn't exist, so instantiate a monomorph and determine its memory
 
        // layout.
 
        self.detect_and_resolve_type_loops_for(modules, heap, concrete_type)?;
 
        debug_assert_eq!(self.encountered_types[0].definition_id, definition_id);
 
        let mono_idx = self.encountered_types[0].monomorph_idx;
 
        self.lay_out_memory_for_encountered_types(arch);
 

	
 
        return Ok(mono_idx as i32);
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Building base types
 
    //--------------------------------------------------------------------------
 

	
 
    /// Builds the base type for an enum. Will not compute byte sizes
 
    fn build_base_enum_definition(&mut self, modules: &[Module], ctx: &mut PassCtx, definition_id: DefinitionId) -> Result<(), ParseError> {
 
        debug_assert!(!self.lookup.contains_key(&definition_id), "base enum already built");
 
        let definition = ctx.heap[definition_id].as_enum();
 
        let root_id = definition.defined_in;
 

	
 
        // Determine enum variants
 
        let mut enum_value = -1;
 
        let mut variants = Vec::with_capacity(definition.variants.len());
 

	
 
        for variant in &definition.variants {
 
            if enum_value == i64::MAX {
 
                let source = &modules[definition.defined_in.index as usize].source;
 
                return Err(ParseError::new_error_str_at_span(
 
                    source, variant.identifier.span,
 
                    "this enum variant has an integer value that is too large"
 
                ));
 
            }
 

	
 
            enum_value += 1;
 
            if let EnumVariantValue::Integer(explicit_value) = variant.value {
 
                enum_value = explicit_value;
 
            }
 

	
 
            variants.push(EnumVariant{
 
                identifier: variant.identifier.clone(),
 
                value: enum_value,
 
            });
 
        }
 

	
 
        // Determine tag size
 
        let mut min_enum_value = 0;
 
        let mut max_enum_value = 0;
 
        if !variants.is_empty() {
 
            min_enum_value = variants[0].value;
 
            max_enum_value = variants[0].value;
 
            for variant in variants.iter().skip(1) {
 
                min_enum_value = min_enum_value.min(variant.value);
 
                max_enum_value = max_enum_value.max(variant.value);
 
            }
 
        }
 

	
 
        let (tag_type, size_and_alignment) = Self::variant_tag_type_from_values(min_enum_value, max_enum_value);
 

	
 
        // Enum names and polymorphic args do not conflict
 
        Self::check_identifier_collision(
 
            modules, root_id, &variants, |variant| &variant.identifier, "enum variant"
 
        )?;
 

	
 
        // Polymorphic arguments cannot appear as embedded types, because
 
        // they can only consist of integer variants.
 
        Self::check_poly_args_collision(modules, ctx, root_id, &definition.poly_vars)?;
 
        let poly_vars = Self::create_polymorphic_variables(&definition.poly_vars);
 

	
 
        self.lookup.insert(definition_id, DefinedType {
 
            ast_root: root_id,
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Enum(EnumType{
 
                variants,
 
                monomorphs: Vec::new(),
 
                minimum_tag_value: min_enum_value,
 
                maximum_tag_value: max_enum_value,
 
                tag_type,
 
                size: size_and_alignment,
 
                alignment: size_and_alignment
 
            }),
 
            poly_vars,
 
            is_polymorph: false,
 
        });
 

	
 
        return Ok(());
 
    }
 

	
 
    /// Builds the base type for a union. Will compute byte sizes.
 
    fn build_base_union_definition(&mut self, modules: &[Module], ctx: &mut PassCtx, definition_id: DefinitionId) -> Result<(), ParseError> {
 
        debug_assert!(!self.lookup.contains_key(&definition_id), "base union already built");
 
        let definition = ctx.heap[definition_id].as_union();
 
        let root_id = definition.defined_in;
 

	
 
        // Check all variants and their embedded types
 
        let mut variants = Vec::with_capacity(definition.variants.len());
 
        let mut tag_counter = 0;
 
        for variant in &definition.variants {
 
            for embedded in &variant.value {
 
                Self::check_member_parser_type(
 
                    modules, ctx, root_id, embedded, false
 
                )?;
 
            }
 

	
 
            variants.push(UnionVariant{
 
                identifier: variant.identifier.clone(),
 
                embedded: variant.value.clone(),
 
                tag_value: tag_counter,
 
            });
 
            tag_counter += 1;
 
        }
 

	
 
        let mut max_tag_value = 0;
 
        if tag_counter != 0 {
 
            max_tag_value = tag_counter - 1
 
        }
 

	
 
        let (tag_type, tag_size) = Self::variant_tag_type_from_values(0, max_tag_value);
 

	
 
        // Make sure there are no conflicts in identifiers
 
        Self::check_identifier_collision(
 
            modules, root_id, &variants, |variant| &variant.identifier, "union variant"
 
        )?;
 
        Self::check_poly_args_collision(modules, ctx, root_id, &definition.poly_vars)?;
 

	
 
        // Construct internal representation of union
 
        let mut poly_vars = Self::create_polymorphic_variables(&definition.poly_vars);
 
        for variant in &definition.variants {
 
            for embedded in &variant.value {
 
                Self::mark_used_polymorphic_variables(&mut poly_vars, embedded);
 
            }
 
        }
 

	
 
        let is_polymorph = poly_vars.iter().any(|arg| arg.is_in_use);
 

	
 
        self.lookup.insert(definition_id, DefinedType{
 
            ast_root: root_id,
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Union(UnionType{
 
                variants,
 
                monomorphs: Vec::new(),
 
                tag_type,
 
                tag_size,
 
            }),
 
            poly_vars,
 
            is_polymorph
 
        });
 

	
 
        return Ok(());
 
    }
 

	
 
    /// Builds base struct type. Will not compute byte sizes.
 
    fn build_base_struct_definition(&mut self, modules: &[Module], ctx: &mut PassCtx, definition_id: DefinitionId) -> Result<(), ParseError> {
 
        debug_assert!(!self.lookup.contains_key(&definition_id), "base struct already built");
 
        let definition = ctx.heap[definition_id].as_struct();
 
        let root_id = definition.defined_in;
 

	
 
        // Check all struct fields and construct internal representation
 
        let mut fields = Vec::with_capacity(definition.fields.len());
 

	
 
        for field in &definition.fields {
 
            Self::check_member_parser_type(
 
                modules, ctx, root_id, &field.parser_type, false
 
            )?;
 

	
 
            fields.push(StructField{
 
                identifier: field.field.clone(),
 
                parser_type: field.parser_type.clone(),
 
            });
 
        }
 

	
 
        // Make sure there are no conflicting variables
 
        Self::check_identifier_collision(
 
            modules, root_id, &fields, |field| &field.identifier, "struct field"
 
        )?;
 
        Self::check_poly_args_collision(modules, ctx, root_id, &definition.poly_vars)?;
 

	
 
        // Construct base type in table
 
        let mut poly_vars = Self::create_polymorphic_variables(&definition.poly_vars);
 
        for field in &fields {
 
            Self::mark_used_polymorphic_variables(&mut poly_vars, &field.parser_type);
 
        }
 

	
 
        let is_polymorph = poly_vars.iter().any(|arg| arg.is_in_use);
 

	
 
        self.lookup.insert(definition_id, DefinedType{
 
            ast_root: root_id,
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Struct(StructType{
 
                fields,
 
                monomorphs: Vec::new(),
 
            }),
 
            poly_vars,
 
            is_polymorph
 
        });
 

	
 
        return Ok(())
 
    }
 

	
 
    /// Builds base function type.
 
    fn build_base_function_definition(&mut self, modules: &[Module], ctx: &mut PassCtx, definition_id: DefinitionId) -> Result<(), ParseError> {
 
        debug_assert!(!self.lookup.contains_key(&definition_id), "base function already built");
 
        let definition = ctx.heap[definition_id].as_function();
 
        let root_id = definition.defined_in;
 

	
 
        // Check and construct return types and argument types.
 
        debug_assert_eq!(definition.return_types.len(), 1, "not one return type");
 
        for return_type in &definition.return_types {
 
            Self::check_member_parser_type(
 
                modules, ctx, root_id, return_type, definition.builtin
 
            )?;
 
        }
 

	
 
        let mut arguments = Vec::with_capacity(definition.parameters.len());
 
        for parameter_id in &definition.parameters {
 
            let parameter = &ctx.heap[*parameter_id];
 
            Self::check_member_parser_type(
 
                modules, ctx, root_id, &parameter.parser_type, definition.builtin
 
            )?;
 

	
 
            arguments.push(FunctionArgument{
 
                identifier: parameter.identifier.clone(),
 
                parser_type: parameter.parser_type.clone(),
 
            });
 
        }
 

	
 
        // Check conflict of identifiers
 
        Self::check_identifier_collision(
 
            modules, root_id, &arguments, |arg| &arg.identifier, "function argument"
 
        )?;
 
        Self::check_poly_args_collision(modules, ctx, root_id, &definition.poly_vars)?;
 

	
 
        // Construct internal representation of function type
 
        let mut poly_vars = Self::create_polymorphic_variables(&definition.poly_vars);
 
        for return_type in &definition.return_types {
 
            Self::mark_used_polymorphic_variables(&mut poly_vars, return_type);
 
        }
 
        for argument in &arguments {
 
            Self::mark_used_polymorphic_variables(&mut poly_vars, &argument.parser_type);
 
        }
 

	
 
        let is_polymorph = poly_vars.iter().any(|arg| arg.is_in_use);
 

	
 
        self.lookup.insert(definition_id, DefinedType{
 
            ast_root: root_id,
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Function(FunctionType{
 
                return_types: definition.return_types.clone(),
 
                arguments,
 
                monomorphs: Vec::new(),
 
            }),
 
            poly_vars,
 
            is_polymorph
 
        });
 

	
 
        return Ok(());
 
    }
 

	
 
    /// Builds base component type.
 
    fn build_base_component_definition(&mut self, modules: &[Module], ctx: &mut PassCtx, definition_id: DefinitionId) -> Result<(), ParseError> {
 
        debug_assert!(!self.lookup.contains_key(&definition_id), "base component already built");
 

	
 
        let definition = &ctx.heap[definition_id].as_component();
 
        let root_id = definition.defined_in;
 

	
 
        // Check the argument types
 
        let mut arguments = Vec::with_capacity(definition.parameters.len());
 
        for parameter_id in &definition.parameters {
 
            let parameter = &ctx.heap[*parameter_id];
 
            Self::check_member_parser_type(
 
                modules, ctx, root_id, &parameter.parser_type, false
 
            )?;
 

	
 
            arguments.push(FunctionArgument{
 
                identifier: parameter.identifier.clone(),
 
                parser_type: parameter.parser_type.clone(),
 
            });
 
        }
 

	
 
        // Check conflict of identifiers
 
        Self::check_identifier_collision(
 
            modules, root_id, &arguments, |arg| &arg.identifier, "connector argument"
 
        )?;
 
        Self::check_poly_args_collision(modules, ctx, root_id, &definition.poly_vars)?;
 

	
 
        // Construct internal representation of component
 
        let mut poly_vars = Self::create_polymorphic_variables(&definition.poly_vars);
 
        for argument in &arguments {
 
            Self::mark_used_polymorphic_variables(&mut poly_vars, &argument.parser_type);
 
        }
 

	
 
        let is_polymorph = poly_vars.iter().any(|arg| arg.is_in_use);
 

	
 
        self.lookup.insert(definition_id, DefinedType{
 
            ast_root: root_id,
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Component(ComponentType{
 
                variant: definition.variant,
 
                arguments,
 
                monomorphs: Vec::new()
 
            }),
 
            poly_vars,
 
            is_polymorph
 
        });
 

	
 
        Ok(())
 
    }
 

	
 
    /// Will check if the member type (field of a struct, embedded type in a
 
    /// union variant) is valid.
 
    fn check_member_parser_type(
 
        modules: &[Module], ctx: &PassCtx, base_definition_root_id: RootId,
 
        member_parser_type: &ParserType, allow_special_compiler_types: bool
 
    ) -> Result<(), ParseError> {
 
        use ParserTypeVariant as PTV;
 

	
 
        for element in &member_parser_type.elements {
 
            match element.variant {
 
                // Special cases
 
                PTV::Void | PTV::InputOrOutput | PTV::ArrayLike | PTV::IntegerLike => {
 
                    if !allow_special_compiler_types {
 
                        unreachable!("compiler-only ParserTypeVariant in member type");
 
                    }
 
                },
 
                // Builtin types, always valid
 
                PTV::Message | PTV::Bool |
 
                PTV::UInt8 | PTV::UInt16 | PTV::UInt32 | PTV::UInt64 |
 
                PTV::SInt8 | PTV::SInt16 | PTV::SInt32 | PTV::SInt64 |
 
                PTV::Character | PTV::String |
 
                PTV::Array | PTV::Input | PTV::Output | PTV::Tuple(_) |
 
                // Likewise, polymorphic variables are always valid
 
                PTV::PolymorphicArgument(_, _) => {},
 
                // Types that are not constructable, or types that are not
 
                // allowed (and checked earlier)
 
                PTV::IntegerLiteral | PTV::Inferred => {
 
                    unreachable!("illegal ParserTypeVariant within type definition");
 
                },
 
                // Finally, user-defined types
 
                PTV::Definition(definition_id, _) => {
 
                    let definition = &ctx.heap[definition_id];
 
                    if !(definition.is_struct() || definition.is_enum() || definition.is_union()) {
 
                        let source = &modules[base_definition_root_id.index as usize].source;
 
                        return Err(ParseError::new_error_str_at_span(
 
                            source, element.element_span, "expected a datatype (a struct, enum or union)"
 
                        ));
 
                    }
 

	
 
                    // Otherwise, we're fine
 
                }
 
            }
 
        }
 

	
 
        // If here, then all elements check out
 
        return Ok(());
 
    }
 

	
 
    /// Go through a list of identifiers and ensure that all identifiers have
 
    /// unique names
 
    fn check_identifier_collision<T: Sized, F: Fn(&T) -> &Identifier>(
 
        modules: &[Module], root_id: RootId, items: &[T], getter: F, item_name: &'static str
 
    ) -> Result<(), ParseError> {
 
        for (item_idx, item) in items.iter().enumerate() {
 
            let item_ident = getter(item);
 
            for other_item in &items[0..item_idx] {
 
                let other_item_ident = getter(other_item);
 
                if item_ident == other_item_ident {
 
                    let module_source = &modules[root_id.index as usize].source;
 
                    return Err(ParseError::new_error_at_span(
 
                        module_source, item_ident.span, format!("This {} is defined more than once", item_name)
 
                    ).with_info_at_span(
 
                        module_source, other_item_ident.span, format!("The other {} is defined here", item_name)
 
                    ));
 
                }
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    /// Go through a list of polymorphic arguments and make sure that the
 
    /// arguments all have unique names, and the arguments do not conflict with
 
    /// any symbols defined at the module scope.
 
    fn check_poly_args_collision(
 
        modules: &[Module], ctx: &PassCtx, root_id: RootId, poly_args: &[Identifier]
 
    ) -> Result<(), ParseError> {
 
        // Make sure polymorphic arguments are unique and none of the
 
        // identifiers conflict with any imported scopes
 
        for (arg_idx, poly_arg) in poly_args.iter().enumerate() {
 
            for other_poly_arg in &poly_args[..arg_idx] {
 
                if poly_arg == other_poly_arg {
 
                    let module_source = &modules[root_id.index as usize].source;
 
                    return Err(ParseError::new_error_str_at_span(
 
                        module_source, poly_arg.span,
 
                        "This polymorphic argument is defined more than once"
 
                    ).with_info_str_at_span(
 
                        module_source, other_poly_arg.span,
 
                        "It conflicts with this polymorphic argument"
 
                    ));
 
                }
 
            }
 

	
 
            // Check if identifier conflicts with a symbol defined or imported
 
            // in the current module
 
            if let Some(symbol) = ctx.symbols.get_symbol_by_name(SymbolScope::Module(root_id), poly_arg.value.as_bytes()) {
 
                // We have a conflict
 
                let module_source = &modules[root_id.index as usize].source;
 
                let introduction_span = symbol.variant.span_of_introduction(ctx.heap);
 
                return Err(ParseError::new_error_str_at_span(
 
                    module_source, poly_arg.span,
 
                    "This polymorphic argument conflicts with another symbol"
 
                ).with_info_str_at_span(
 
                    module_source, introduction_span,
 
                    "It conflicts due to this symbol"
 
                ));
 
            }
 
        }
 

	
 
        // All arguments are fine
 
        Ok(())
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Detecting type loops
 
    //--------------------------------------------------------------------------
 

	
 
    /// Internal function that will detect type loops and check if they're
 
    /// resolvable. If so then the appropriate union variants will be marked as
 
    /// "living on heap". If not then a `ParseError` will be returned
 
    fn detect_and_resolve_type_loops_for(&mut self, modules: &[Module], heap: &Heap, concrete_type: ConcreteType) -> Result<(), ParseError> {
 
        use DefinedTypeVariant as DTV;
 

	
 
        debug_assert!(self.type_loop_breadcrumbs.is_empty());
 
        debug_assert!(self.type_loops.is_empty());
 
        debug_assert!(self.encountered_types.is_empty());
 

	
 
        // Push the initial breadcrumb
 
        let initial_breadcrumb = self.check_member_for_type_loops(&concrete_type);
 
        if let TypeLoopResult::PushBreadcrumb(definition_id, concrete_type) = initial_breadcrumb {
 
            self.handle_new_breadcrumb_for_type_loops(definition_id, concrete_type);
 
        } else {
 
            unreachable!();
 
        }
 

	
 
        // Enter into the main resolving loop
 
        while !self.type_loop_breadcrumbs.is_empty() {
 
            // Because we might be modifying the breadcrumb array we need to
 
            let breadcrumb_idx = self.type_loop_breadcrumbs.len() - 1;
 
            let mut breadcrumb = self.type_loop_breadcrumbs[breadcrumb_idx].clone();
 

	
 
            let poly_type = self.lookup.get(&breadcrumb.definition_id).unwrap();
 

	
 
            let resolve_result = match &poly_type.definition {
 
                DTV::Enum(_) => {
 
                    TypeLoopResult::TypeExists
 
                },
 
                DTV::Union(definition) => {
 
                    let monomorph = &definition.monomorphs[breadcrumb.monomorph_idx];
 
                    let num_variants = monomorph.variants.len();
 

	
 
                    let mut union_result = TypeLoopResult::TypeExists;
 

	
 
                    'member_loop: while breadcrumb.next_member < num_variants {
 
                        let mono_variant = &monomorph.variants[breadcrumb.next_member];
 
                        let num_embedded = mono_variant.embedded.len();
 

	
 
                        while breadcrumb.next_embedded < num_embedded {
 
                            let mono_embedded = &mono_variant.embedded[breadcrumb.next_embedded];
 
                            union_result = self.check_member_for_type_loops(&mono_embedded.concrete_type);
 

	
 
                            if union_result != TypeLoopResult::TypeExists {
 
                                // In type loop or new breadcrumb pushed, so
 
                                // break out of the resolving loop
 
                                break 'member_loop;
 
                            }
 

	
 
                            breadcrumb.next_embedded += 1;
 
                        }
 

	
 
                        breadcrumb.next_embedded = 0;
 
                        breadcrumb.next_member += 1
 
                    }
 

	
 
                    union_result
 
                },
 
                DTV::Struct(definition) => {
 
                    let monomorph = &definition.monomorphs[breadcrumb.monomorph_idx];
 
                    let num_fields = monomorph.fields.len();
 

	
 
                    let mut struct_result = TypeLoopResult::TypeExists;
 
                    while breadcrumb.next_member < num_fields {
 
                        let mono_field = &monomorph.fields[breadcrumb.next_member];
 
                        struct_result = self.check_member_for_type_loops(&mono_field.concrete_type);
 

	
 
                        if struct_result != TypeLoopResult::TypeExists {
 
                            // Type loop or breadcrumb pushed, so break out of
 
                            // the resolving loop
 
                            break;
 
                        }
 

	
 
                        breadcrumb.next_member += 1;
 
                    }
 

	
 
                    struct_result
 
                },
 
                DTV::Function(_) | DTV::Component(_) => unreachable!(),
 
            };
 

	
 
            // Handle the result of attempting to resolve the current breadcrumb
 
            match resolve_result {
 
                TypeLoopResult::TypeExists => {
 
                    // We finished parsing the type
 
                    self.type_loop_breadcrumbs.pop();
 
                },
 
                TypeLoopResult::PushBreadcrumb(definition_id, concrete_type) => {
 
                    // We recurse into the member type.
 
                    self.type_loop_breadcrumbs[breadcrumb_idx] = breadcrumb;
 
                    self.handle_new_breadcrumb_for_type_loops(definition_id, concrete_type);
 
                },
 
                TypeLoopResult::TypeLoop(first_idx) => {
 
                    // Because we will be modifying breadcrumbs within the
 
                    // type-loop handling code, put back the modified breadcrumb
 
                    self.type_loop_breadcrumbs[breadcrumb_idx] = breadcrumb;
 

	
 
                    // We're in a type loop. Add the type loop
 
                    let mut loop_members = Vec::with_capacity(self.type_loop_breadcrumbs.len() - first_idx);
 
                    let mut contains_union = false;
 

	
 
                    for breadcrumb_idx in first_idx..self.type_loop_breadcrumbs.len() {
 
                        let breadcrumb = &mut self.type_loop_breadcrumbs[breadcrumb_idx];
 
                        let mut is_union = false;
 

	
 
                        let entry = self.lookup.get_mut(&breadcrumb.definition_id).unwrap();
 
                        match &mut entry.definition {
 
                            DTV::Union(definition) => {
 
                                // Mark the currently processed variant as requiring heap
 
                                // allocation, then advance the *embedded* type. The loop above
 
                                // will then take care of advancing it to the next *member*.
 
                                let monomorph = &mut definition.monomorphs[breadcrumb.monomorph_idx];
 
                                let variant = &mut monomorph.variants[breadcrumb.next_member];
 
                                variant.lives_on_heap = true;
 
                                breadcrumb.next_embedded += 1;
 
                                is_union = true;
 
                                contains_union = true;
 
                            },
 
                            _ => {}, // else: we don't care for now
 
                        }
 

	
 
                        loop_members.push(TypeLoopEntry{
 
                            definition_id: breadcrumb.definition_id,
 
                            monomorph_idx: breadcrumb.monomorph_idx,
 
                            is_union
 
                        });
 
                    }
 

	
 
                    let new_type_loop = TypeLoop{ members: loop_members };
 
                    if !contains_union {
 
                        // No way to (potentially) break the union. So return a
 
                        // type loop error. This is because otherwise our
 
                        // breadcrumb resolver ends up in an infinite loop.
 
                        return Err(construct_type_loop_error(
 
                            self, &new_type_loop, modules, heap
 
                        ));
 
                    }
 

	
 
                    self.type_loops.push(new_type_loop);
 
                }
 
            }
 
        }
 

	
 
        // All breadcrumbs have been cleared. So now `type_loops` contains all
 
        // of the encountered type loops, and `encountered_types` contains a
 
        // list of all unique monomorphs we encountered.
 

	
 
        // The next step is to figure out if all of the type loops can be
 
        // broken. A type loop can be broken if at least one union exists in the
 
        // loop and that union ended up having variants that are not part of
 
        // a type loop.
 
        fn type_loop_source_span_and_message<'a>(
 
            modules: &'a [Module], heap: &Heap, defined_type: &DefinedType, monomorph_idx: usize, index_in_loop: usize
 
        ) -> (&'a InputSource, InputSpan, String) {
 
            // Note: because we will discover the type loop the *first* time we
 
            // instantiate a monomorph with the provided polymorphic arguments
 
            // (not all arguments are actually used in the type). We don't have
 
            // to care about a second instantiation where certain unused
 
            // polymorphic arguments are different.
 
            let monomorph_type = match &defined_type.definition {
 
                DTV::Union(definition) => &definition.monomorphs[monomorph_idx].concrete_type,
 
                DTV::Struct(definition) => &definition.monomorphs[monomorph_idx].concrete_type,
 
                DTV::Enum(_) | DTV::Function(_) | DTV::Component(_) =>
 
                    unreachable!(), // impossible to have an enum/procedure in a type loop
 
            };
 

	
 
            let type_name = monomorph_type.display_name(&heap);
 
            let message = if index_in_loop == 0 {
 
                format!(
 
                    "encountered an infinitely large type for '{}' (which can be fixed by \
 
                    introducing a union type that has a variant whose embedded types are \
 
                    not part of a type loop, or do not have embedded types)",
 
                    type_name
 
                )
 
            } else if index_in_loop == 1 {
 
                format!("because it depends on the type '{}'", type_name)
 
            } else {
 
                format!("which depends on the type '{}'", type_name)
 
            };
 

	
 
            let ast_definition = &heap[defined_type.ast_definition];
 
            let ast_root_id = ast_definition.defined_in();
 

	
 
            return (
 
                &modules[ast_root_id.index as usize].source,
 
                ast_definition.identifier().span,
 
                message
 
            );
 
        }
 

	
 
        fn construct_type_loop_error(table: &TypeTable, type_loop: &TypeLoop, modules: &[Module], heap: &Heap) -> ParseError {
 
            let first_entry = &type_loop.members[0];
 
            let first_type = table.lookup.get(&first_entry.definition_id).unwrap();
 
            let (first_module, first_span, first_message) = type_loop_source_span_and_message(
 
                modules, heap, first_type, first_entry.monomorph_idx, 0
 
            );
 
            let mut parse_error = ParseError::new_error_at_span(first_module, first_span, first_message);
 

	
 
            for member_idx in 1..type_loop.members.len() {
 
                let entry = &type_loop.members[member_idx];
 
                let entry_type = table.lookup.get(&first_entry.definition_id).unwrap();
 
                let (module, span, message) = type_loop_source_span_and_message(
 
                    modules, heap, entry_type, entry.monomorph_idx, member_idx
 
                );
 
                parse_error = parse_error.with_info_at_span(module, span, message);
 
            }
 

	
 
            parse_error
 
        }
 

	
 
        for type_loop in &self.type_loops {
 
            let mut can_be_broken = false;
 
            debug_assert!(!type_loop.members.is_empty());
 

	
 
            for entry in &type_loop.members {
 
                if entry.is_union {
 
                    let base_type = self.lookup.get(&entry.definition_id).unwrap();
 
                    let monomorph = &base_type.definition.as_union().monomorphs[entry.monomorph_idx];
 

	
 
                    debug_assert!(!monomorph.variants.is_empty()); // otherwise it couldn't be part of the type loop
 
                    let has_stack_variant = monomorph.variants.iter().any(|variant| !variant.lives_on_heap);
 
                    if has_stack_variant {
 
                        can_be_broken = true;
 
                    }
 
                }
 
            }
 

	
 
            if !can_be_broken {
 
                // Construct a type loop error
 
                return Err(construct_type_loop_error(self, type_loop, modules, heap));
 
            }
 
        }
 

	
 
        // If here, then all type loops have been resolved and we can lay out
 
        // all of the members
 
        self.type_loops.clear();
 

	
 
        return Ok(());
 
    }
 

	
 
    /// Checks if the specified type needs to be resolved (i.e. we need to push
 
    /// a breadcrumb), is already resolved (i.e. we can continue with the next
 
    /// member of the currently considered type) or is in the process of being
 
    /// resolved (i.e. we're in a type loop). Because of borrowing rules we
 
    /// don't do any modifications of internal types here. Hence: if we
 
    /// return `PushBreadcrumb` then call `handle_new_breadcrumb_for_type_loops`
 
    /// to take care of storing the appropriate types.
 
    fn check_member_for_type_loops(&self, definition_type: &ConcreteType) -> TypeLoopResult {
 
        use ConcreteTypePart as CTP;
 

	
 
        // We're only interested in user-defined types, so exit if it is a
 
        // builtin of some sort.
 
        debug_assert!(!definition_type.parts.is_empty());
 
        let definition_id = match &definition_type.parts[0] {
 
            CTP::Instance(definition_id, _) |
 
            CTP::Function(definition_id, _) |
 
            CTP::Component(definition_id, _) => {
 
                *definition_id
 
            },
 
            _ => {
 
                return TypeLoopResult::TypeExists
 
            },
 
        };
 

	
 
        let base_type = self.lookup.get(&definition_id).unwrap();
 
        if let Some(mono_idx) = base_type.get_monomorph_index(&definition_type.parts) {
 
            // Monomorph is already known. Check if it is present in the
 
            // breadcrumbs. If so, then we are in a type loop
 
            for (breadcrumb_idx, breadcrumb) in self.type_loop_breadcrumbs.iter().enumerate() {
 
                if breadcrumb.definition_id == definition_id && breadcrumb.monomorph_idx == mono_idx {
 
                    return TypeLoopResult::TypeLoop(breadcrumb_idx);
 
                }
 
            }
 

	
 
            return TypeLoopResult::TypeExists;
 
        }
 

	
 
        // Type is not yet known, so we need to insert it into the lookup and
 
        // push a new breadcrumb.
 
        return TypeLoopResult::PushBreadcrumb(definition_id, definition_type.clone());
 
    }
 

	
 
    /// Handles the `PushBreadcrumb` result for a `check_member_for_type_loops`
 
    /// call.
 
    fn handle_new_breadcrumb_for_type_loops(&mut self, definition_id: DefinitionId, definition_type: ConcreteType) {
 
        use DefinedTypeVariant as DTV;
 

	
 
        let base_type = self.lookup.get_mut(&definition_id).unwrap();
 
        let mut is_union = false;
 
        let monomorph_idx = match &mut base_type.definition {
 
            DTV::Enum(definition) => {
 
                debug_assert!(definition.monomorphs.is_empty());
 
                definition.monomorphs.push(EnumMonomorph{
 
                    concrete_type: definition_type,
 
                });
 
                0
 
            },
 
            DTV::Union(definition) => {
 
                // Create all the variants with their concrete types
 
                let mut mono_variants = Vec::with_capacity(definition.variants.len());
 
                for poly_variant in &definition.variants {
 
                    let mut mono_embedded = Vec::with_capacity(poly_variant.embedded.len());
 
                    for poly_embedded in &poly_variant.embedded {
 
                        let mono_concrete = Self::construct_concrete_type(poly_embedded, &definition_type);
 
                        mono_embedded.push(UnionMonomorphEmbedded{
 
                            concrete_type: mono_concrete,
 
                            size: 0,
 
                            alignment: 0,
 
                            offset: 0
 
                        });
 
                    }
 

	
 
                    mono_variants.push(UnionMonomorphVariant{
 
                        lives_on_heap: false,
 
                        embedded: mono_embedded,
 
                    })
 
                }
 

	
 
                let mono_idx = definition.monomorphs.len();
 
                definition.monomorphs.push(UnionMonomorph{
 
                    concrete_type: definition_type,
 
                    variants: mono_variants,
 
                    stack_size: 0,
 
                    stack_alignment: 0,
 
                    heap_size: 0,
 
                    heap_alignment: 0
 
                });
 

	
 
                is_union = true;
 
                mono_idx
 
            },
 
            DTV::Struct(definition) => {
 
                let mut mono_fields = Vec::with_capacity(definition.fields.len());
 
                for poly_field in &definition.fields {
 
                    let mono_concrete = Self::construct_concrete_type(&poly_field.parser_type, &definition_type);
 
                    mono_fields.push(StructMonomorphField{
 
                        concrete_type: mono_concrete,
 
                        size: 0,
 
                        alignment: 0,
 
                        offset: 0
 
                    })
 
                }
 

	
 
                let mono_idx = definition.monomorphs.len();
 
                definition.monomorphs.push(StructMonomorph{
 
                    concrete_type: definition_type,
 
                    fields: mono_fields,
 
                    size: 0,
 
                    alignment: 0
 
                });
 

	
 
                mono_idx
 
            },
 
            DTV::Function(_) | DTV::Component(_) => {
 
                unreachable!("pushing type resolving breadcrumb for procedure type")
 
            },
 
        };
 

	
 
        self.encountered_types.push(TypeLoopEntry{
 
            definition_id,
 
            monomorph_idx,
 
            is_union,
 
        });
 

	
 
        self.type_loop_breadcrumbs.push(TypeLoopBreadcrumb{
 
            definition_id,
 
            monomorph_idx,
 
            next_member: 0,
 
            next_embedded: 0,
 
        });
 
    }
 

	
 
    /// Constructs a concrete type out of a parser type for a struct field or
 
    /// union embedded type. It will do this by looking up the polymorphic
 
    /// variables in the supplied concrete type. The assumption is that the
 
    /// polymorphic variable's indices correspond to the subtrees in the
 
    /// concrete type.
 
    fn construct_concrete_type(member_type: &ParserType, container_type: &ConcreteType) -> ConcreteType {
 
        use ParserTypeVariant as PTV;
 
        use ConcreteTypePart as CTP;
 

	
 
        // TODO: Combine with code in pass_typing.rs
 
        fn parser_to_concrete_part(part: &ParserTypeVariant) -> Option<ConcreteTypePart> {
 
            match part {
 
                PTV::Void      => Some(CTP::Void),
 
                PTV::Message   => Some(CTP::Message),
 
                PTV::Bool      => Some(CTP::Bool),
 
                PTV::UInt8     => Some(CTP::UInt8),
 
                PTV::UInt16    => Some(CTP::UInt16),
 
                PTV::UInt32    => Some(CTP::UInt32),
 
                PTV::UInt64    => Some(CTP::UInt64),
 
                PTV::SInt8     => Some(CTP::SInt8),
 
                PTV::SInt16    => Some(CTP::SInt16),
 
                PTV::SInt32    => Some(CTP::SInt32),
 
                PTV::SInt64    => Some(CTP::SInt64),
 
                PTV::Character => Some(CTP::Character),
 
                PTV::String    => Some(CTP::String),
 
                PTV::Array     => Some(CTP::Array),
 
                PTV::Input     => Some(CTP::Input),
 
                PTV::Output    => Some(CTP::Output),
 
                PTV::Tuple(num) => Some(CTP::Tuple(*num)),
 
                PTV::Definition(definition_id, num) => Some(CTP::Instance(*definition_id, *num)),
 
                _              => None
 
            }
 
        }
 

	
 
        let mut parts = Vec::with_capacity(member_type.elements.len()); // usually a correct estimation, might not be
 
        for member_part in &member_type.elements {
 
            // Check if we have a regular builtin type
 
            if let Some(part) = parser_to_concrete_part(&member_part.variant) {
 
                parts.push(part);
 
                continue;
 
            }
 

	
 
            // Not builtin, but if all code is working correctly, we only care
 
            // about the polymorphic argument at this point.
 
            if let PTV::PolymorphicArgument(_container_definition_id, poly_arg_idx) = member_part.variant {
 
                debug_assert_eq!(_container_definition_id, get_concrete_type_definition(container_type));
 

	
 
                let mut container_iter = container_type.embedded_iter(0);
 
                for _ in 0..poly_arg_idx {
 
                    container_iter.next();
 
                }
 

	
 
                let poly_section = container_iter.next().unwrap();
 
                parts.extend(poly_section);
 

	
 
                continue;
 
            }
 

	
 
            unreachable!("unexpected type part {:?} from {:?}", member_part, member_type);
 
        }
 

	
 
        return ConcreteType{ parts };
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Determining memory layout for types
 
    //--------------------------------------------------------------------------
 

	
 
    fn lay_out_memory_for_encountered_types(&mut self, arch: &TargetArch) {
 
        use DefinedTypeVariant as DTV;
 

	
 
        // Just finished type loop detection, so we're left with the encountered
 
        // types only
 
        debug_assert!(self.type_loops.is_empty());
 
        debug_assert!(!self.encountered_types.is_empty());
 
        debug_assert!(self.memory_layout_breadcrumbs.is_empty());
 
        debug_assert!(self.size_alignment_stack.is_empty());
 

	
 
        // Push the first entry (the type we originally started with when we
 
        // were detecting type loops)
 
        let first_entry = &self.encountered_types[0];
 
        self.memory_layout_breadcrumbs.push(MemoryBreadcrumb{
 
            definition_id: first_entry.definition_id,
 
            monomorph_idx: first_entry.monomorph_idx,
 
            next_member: 0,
 
            next_embedded: 0,
 
            first_size_alignment_idx: 0,
 
        });
 

	
 
        // Enter the main resolving loop
 
        'breadcrumb_loop: while !self.memory_layout_breadcrumbs.is_empty() {
 
            let cur_breadcrumb_idx = self.memory_layout_breadcrumbs.len() - 1;
 
            let mut breadcrumb = self.memory_layout_breadcrumbs[cur_breadcrumb_idx].clone();
 

	
 
            let poly_type = self.lookup.get(&breadcrumb.definition_id).unwrap();
 
            match &poly_type.definition {
 
                DTV::Enum(definition) => {
 
                    // Size should already be computed
 
                    debug_assert!(definition.size != 0 && definition.alignment != 0);
 
                },
 
                DTV::Union(definition) => {
 
                    // Retrieve size/alignment of each embedded type. We do not
 
                    // compute the offsets or total type sizes yet.
 
                    let mono_type = &definition.monomorphs[breadcrumb.monomorph_idx];
 
                    let num_variants = mono_type.variants.len();
 
                    while breadcrumb.next_member < num_variants {
 
                        let mono_variant = &mono_type.variants[breadcrumb.next_member];
 

	
 
                        if mono_variant.lives_on_heap {
 
                            // To prevent type loops we made this a heap-
 
                            // allocated variant. This implies we cannot
 
                            // compute sizes of members at this point.
 
                        } else {
 
                            let num_embedded = mono_variant.embedded.len();
 
                            while breadcrumb.next_embedded < num_embedded {
 
                                let mono_embedded = &mono_variant.embedded[breadcrumb.next_embedded];
 
                                match self.get_memory_layout_or_breadcrumb(arch, &mono_embedded.concrete_type.parts) {
 
                                    MemoryLayoutResult::TypeExists(size, alignment) => {
 
                                        self.size_alignment_stack.push((size, alignment));
 
                                    },
 
                                    MemoryLayoutResult::PushBreadcrumb(new_breadcrumb) => {
 
                                        self.memory_layout_breadcrumbs[cur_breadcrumb_idx] = breadcrumb;
 
                                        self.memory_layout_breadcrumbs.push(new_breadcrumb);
 
                                        continue 'breadcrumb_loop;
 
                                    }
 
                                }
 

	
 
                                breadcrumb.next_embedded += 1;
 
                            }
 
                        }
 

	
 
                        breadcrumb.next_member += 1;
 
                        breadcrumb.next_embedded = 0;
 
                    }
 

	
 
                    // If here then we can at least compute the stack size of
 
                    // the type, we'll have to come back at the very end to
 
                    // fill in the heap size/alignment/offset of each heap-
 
                    // allocated variant.
 
                    let mut max_size = definition.tag_size;
 
                    let mut max_alignment = definition.tag_size;
 

	
 
                    let poly_type = self.lookup.get_mut(&breadcrumb.definition_id).unwrap();
 
                    let definition = poly_type.definition.as_union_mut();
 
                    let mono_type = &mut definition.monomorphs[breadcrumb.monomorph_idx];
 
                    let mut size_alignment_idx = breadcrumb.first_size_alignment_idx;
 

	
 
                    for variant in &mut mono_type.variants {
 
                        // We're doing stack computations, so always start with
 
                        // the tag size/alignment.
 
                        let mut variant_offset = definition.tag_size;
 
                        let mut variant_alignment = definition.tag_size;
 

	
 
                        if variant.lives_on_heap {
 
                            // Variant lives on heap, so just a pointer
 
                            let (ptr_size, ptr_align) = arch.pointer_size_alignment;
 
                            align_offset_to(&mut variant_offset, ptr_align);
 

	
 
                            variant_offset += ptr_size;
 
                            variant_alignment = variant_alignment.max(ptr_align);
 
                        } else {
 
                            // Variant lives on stack, so walk all embedded
 
                            // types.
 
                            for embedded in &mut variant.embedded {
 
                                let (size, alignment) = self.size_alignment_stack[size_alignment_idx];
 
                                embedded.size = size;
 
                                embedded.alignment = alignment;
 
                                size_alignment_idx += 1;
 

	
 
                                align_offset_to(&mut variant_offset, alignment);
 
                                embedded.offset = variant_offset;
 

	
 
                                variant_offset += size;
 
                                variant_alignment = variant_alignment.max(alignment);
 
                            }
 
                        };
 

	
 
                        max_size = max_size.max(variant_offset);
 
                        max_alignment = max_alignment.max(variant_alignment);
 
                    }
 

	
 
                    mono_type.stack_size = max_size;
 
                    mono_type.stack_alignment = max_alignment;
 
                    self.size_alignment_stack.truncate(breadcrumb.first_size_alignment_idx);
 
                },
 
                DTV::Struct(definition) => {
 
                    // Retrieve size and alignment of each struct member. We'll
 
                    // compute the offsets once all of those are known
 
                    let mono_type = &definition.monomorphs[breadcrumb.monomorph_idx];
 
                    let num_fields = mono_type.fields.len();
 
                    while breadcrumb.next_member < num_fields {
 
                        let mono_field = &mono_type.fields[breadcrumb.next_member];
 

	
 
                        match self.get_memory_layout_or_breadcrumb(arch, &mono_field.concrete_type.parts) {
 
                            MemoryLayoutResult::TypeExists(size, alignment) => {
 
                                self.size_alignment_stack.push((size, alignment))
 
                            },
 
                            MemoryLayoutResult::PushBreadcrumb(new_breadcrumb) => {
 
                                self.memory_layout_breadcrumbs[cur_breadcrumb_idx] = breadcrumb;
 
                                self.memory_layout_breadcrumbs.push(new_breadcrumb);
 
                                continue 'breadcrumb_loop;
 
                            },
 
                        }
 

	
 
                        breadcrumb.next_member += 1;
 
                    }
 

	
 
                    // Compute offsets and size of total type
 
                    let mut cur_offset = 0;
 
                    let mut max_alignment = 1;
 

	
 
                    let poly_type = self.lookup.get_mut(&breadcrumb.definition_id).unwrap();
 
                    let definition = poly_type.definition.as_struct_mut();
 
                    let mono_type = &mut definition.monomorphs[breadcrumb.monomorph_idx];
 
                    let mut size_alignment_idx = breadcrumb.first_size_alignment_idx;
 

	
 
                    for field in &mut mono_type.fields {
 
                        let (size, alignment) = self.size_alignment_stack[size_alignment_idx];
 
                        field.size = size;
 
                        field.alignment = alignment;
 
                        size_alignment_idx += 1;
 

	
 
                        align_offset_to(&mut cur_offset, alignment);
 
                        field.offset = cur_offset;
 

	
 
                        cur_offset += size;
 
                        max_alignment = max_alignment.max(alignment);
 
                    }
 

	
 
                    mono_type.size = cur_offset;
 
                    mono_type.alignment = max_alignment;
 
                    self.size_alignment_stack.truncate(breadcrumb.first_size_alignment_idx);
 
                },
 
                DTV::Function(_) | DTV::Component(_) => {
 
                    unreachable!();
 
                }
 
            }
 

	
 
            // If here, then we completely layed out the current type. So move
 
            // to the next breadcrumb
 
            self.memory_layout_breadcrumbs.pop();
 
        }
 

	
 
        debug_assert!(self.size_alignment_stack.is_empty());
 

	
 
        // If here then all types have been layed out. What remains is to
 
        // compute the sizes/alignment/offsets of the heap variants of the
 
        // unions we have encountered.
 
        for entry in &self.encountered_types {
 
            if !entry.is_union {
 
                continue;
 
            }
 

	
 
            // First pass, use buffer to store size/alignment to prevent
 
            // borrowing issues.
 
            let poly_type = self.lookup.get(&entry.definition_id).unwrap();
 
            let definition = poly_type.definition.as_union();
 
            let mono_type = &definition.monomorphs[entry.monomorph_idx];
 

	
 
            for variant in &mono_type.variants {
 
                if !variant.lives_on_heap {
 
                    continue;
 
                }
 

	
 
                debug_assert!(!variant.embedded.is_empty());
 

	
 
                for embedded in &variant.embedded {
 
                    match self.get_memory_layout_or_breadcrumb(arch, &embedded.concrete_type.parts) {
 
                        MemoryLayoutResult::TypeExists(size, alignment) => {
 
                            self.size_alignment_stack.push((size, alignment));
 
                        },
 
                        _ => unreachable!(),
 
                    }
 
                }
 
            }
 

	
 
            // Second pass, apply the size/alignment values in our buffer
 
            let poly_type = self.lookup.get_mut(&entry.definition_id).unwrap();
 
            let definition = poly_type.definition.as_union_mut();
 
            let mono_type = &mut definition.monomorphs[entry.monomorph_idx];
 

	
 
            let mut max_size = 0;
 
            let mut max_alignment = 1;
 
            let mut size_alignment_idx = 0;
 

	
 
            for variant in &mut mono_type.variants {
 
                if !variant.lives_on_heap {
 
                    continue;
 
                }
 

	
 
                let mut variant_offset = 0;
 
                let mut variant_alignment = 1;
 

	
 
                for embedded in &mut variant.embedded {
 
                    let (size, alignment) = self.size_alignment_stack[size_alignment_idx];
 
                    embedded.size = size;
 
                    embedded.alignment = alignment;
 
                    size_alignment_idx += 1;
 

	
 
                    align_offset_to(&mut variant_offset, alignment);
 
                    embedded.alignment = variant_offset;
 

	
 
                    variant_offset += size;
 
                    variant_alignment = variant_alignment.max(alignment);
 
                }
 

	
 
                max_size = max_size.max(variant_offset);
 
                max_alignment = max_alignment.max(variant_alignment);
 
            }
 

	
 
            if max_size != 0 {
 
                // At least one entry lives on the heap
 
                mono_type.heap_size = max_size;
 
                mono_type.heap_alignment = max_alignment;
 
            }
 
        }
 

	
 
        // And now, we're actually, properly, done
 
        self.encountered_types.clear();
 
    }
 

	
 
    fn get_memory_layout_or_breadcrumb(&self, arch: &TargetArch, parts: &[ConcreteTypePart]) -> MemoryLayoutResult {
 
        use ConcreteTypePart as CTP;
 

	
 
        // Before we do any fancy shenanigans, we need to check if the concrete
 
        // type actually requires laying out memory.
 
        debug_assert!(!parts.is_empty());
 
        let (builtin_size, builtin_alignment) = match parts[0] {
 
            CTP::Void   => (0, 1),
 
            CTP::Message => arch.array_size_alignment,
 
            CTP::Bool   => (1, 1),
 
            CTP::UInt8  => (1, 1),
 
            CTP::UInt16 => (2, 2),
 
            CTP::UInt32 => (4, 4),
 
            CTP::UInt64 => (8, 8),
 
            CTP::SInt8  => (1, 1),
 
            CTP::SInt16 => (2, 2),
 
            CTP::SInt32 => (4, 4),
 
            CTP::SInt64 => (8, 8),
 
            CTP::Character => (4, 4),
 
            CTP::String => arch.string_size_alignment,
 
            CTP::Array => arch.array_size_alignment,
 
            CTP::Slice => arch.array_size_alignment,
 
            CTP::Input => arch.port_size_alignment,
 
            CTP::Output => arch.port_size_alignment,
 
            CTP::Tuple(num_embedded) => {
 
                if num_embedded == 0 {
 
                    (0, 1)
 
                } else {
 
                    // TODO: This is a bit hacky: structs and unions are neatly
 
                    //  layed out element by element using the breadcrumbs, but
 
                    //  here we do special tuple checking. Tuples should be able
 
                    //  to get their own breadcrumbs for resolving (and storage
 
                    //  in the type table!)
 
                    debug_assert!(num_embedded > 1);
 
                    let mut total_size = 0;
 
                    let mut total_alignment = 1;
 
                    for embedded in ConcreteTypeIter::new(parts, 0) {
 
                        match self.get_memory_layout_or_breadcrumb(arch, embedded) {
 
                            MemoryLayoutResult::PushBreadcrumb(new_breadcrumb) => {
 
                                return MemoryLayoutResult::PushBreadcrumb(new_breadcrumb);
 
                            },
 
                            MemoryLayoutResult::TypeExists(embedded_size, embedded_alignment) => {
 
                                align_offset_to(&mut total_size, embedded_alignment);
 
                                total_size += embedded_size;
 
                                total_alignment = total_alignment.max(embedded_alignment);
 
                            }
 
                        }
 
                    }
 

	
 
                    (total_size, total_alignment)
 
                }
 
            },
 
            CTP::Instance(definition_id, _) => {
 
                // Retrieve entry and the specific monomorph index by applying
 
                // the full concrete type.
 
                let entry = self.lookup.get(&definition_id).unwrap();
 
                let monomorph_idx = entry.get_monomorph_index(parts).unwrap();
 

	
 
                // Check if this monomorph has its size and alignment layed out,
 
                // and if so: return it.
 
                if let Some((size, alignment)) = entry.get_monomorph_size_alignment(monomorph_idx) {
 
                    // Type has been layed out in memory
 
                    return MemoryLayoutResult::TypeExists(size, alignment);
 
                } else {
 
                    return MemoryLayoutResult::PushBreadcrumb(MemoryBreadcrumb{
 
                        definition_id,
 
                        monomorph_idx,
 
                        next_member: 0,
 
                        next_embedded: 0,
 
                        first_size_alignment_idx: self.size_alignment_stack.len(),
 
                    });
 
                }
 
            },
 
            CTP::Function(_, _) | CTP::Component(_, _) => {
 
                todo!("storage for 'function pointers'");
 
            }
 
        };
 

	
 
        return MemoryLayoutResult::TypeExists(builtin_size, builtin_alignment);
 
    }
 

	
 
    /// Returns tag concrete type (always a builtin integer type), the size of
 
    /// that type in bytes (and implicitly, its alignment)
 
    fn variant_tag_type_from_values(min_val: i64, max_val: i64) -> (ConcreteType, usize) {
 
        debug_assert!(min_val <= max_val);
 

	
 
        let (part, size) = if min_val >= 0 {
 
            // Can be an unsigned integer
 
            if max_val <= (u8::MAX as i64) {
 
                (ConcreteTypePart::UInt8, 1)
 
            } else if max_val <= (u16::MAX as i64) {
 
                (ConcreteTypePart::UInt16, 2)
 
            } else if max_val <= (u32::MAX as i64) {
 
                (ConcreteTypePart::UInt32, 4)
 
            } else {
 
                (ConcreteTypePart::UInt64, 8)
 
            }
 
        } else {
 
            // Must be a signed integer
 
            if min_val >= (i8::MIN as i64) && max_val <= (i8::MAX as i64) {
 
                (ConcreteTypePart::SInt8, 1)
 
            } else if min_val >= (i16::MIN as i64) && max_val <= (i16::MAX as i64) {
 
                (ConcreteTypePart::SInt16, 2)
 
            } else if min_val >= (i32::MIN as i64) && max_val <= (i32::MAX as i64) {
 
                (ConcreteTypePart::SInt32, 4)
 
            } else {
 
                (ConcreteTypePart::SInt64, 8)
 
            }
 
        };
 

	
 
        return (ConcreteType{ parts: vec![part] }, size);
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Small utilities
 
    //--------------------------------------------------------------------------
 

	
 
    fn create_polymorphic_variables(variables: &[Identifier]) -> Vec<PolymorphicVariable> {
 
        let mut result = Vec::with_capacity(variables.len());
 
        for variable in variables.iter() {
 
            result.push(PolymorphicVariable{ identifier: variable.clone(), is_in_use: false });
 
        }
 

	
 
        result
 
    }
 

	
 
    fn mark_used_polymorphic_variables(poly_vars: &mut Vec<PolymorphicVariable>, parser_type: &ParserType) {
 
        for element in &parser_type.elements {
 
            if let ParserTypeVariant::PolymorphicArgument(_, idx) = &element.variant {
 
                poly_vars[*idx as usize].is_in_use = true;
 
            }
 
        }
 
    }
 
}
 

	
 
#[inline]
 
fn align_offset_to(offset: &mut usize, alignment: usize) {
 
    debug_assert!(alignment > 0);
 
    let alignment_min_1 = alignment - 1;
 
    *offset += alignment_min_1;
 
    *offset &= !(alignment_min_1);
 
}
 

	
 
#[inline]
 
fn get_concrete_type_definition(concrete: &ConcreteType) -> DefinitionId {
 
    if let ConcreteTypePart::Instance(definition_id, _) = concrete.parts[0] {
 
        return definition_id;
 
    } else {
 
        debug_assert!(false, "passed {:?} to the type table", concrete);
 
        return DefinitionId::new_invalid()
 
    }
 
}
 
\ No newline at end of file
src/protocol/tests/parser_validation.rs
Show inline comments
 
/// parser_validation.rs
 
///
 
/// Simple tests for the validation phase
 

	
 
use super::*;
 

	
 
#[test]
 
fn test_correct_struct_instance() {
 
    Tester::new_single_source_expect_ok(
 
        "single field",
 
        "
 
        struct Foo { s32 a }
 
        func bar(s32 arg) -> Foo { return Foo{ a: arg }; }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "multiple fields",
 
        "
 
        struct Foo { s32 a, s32 b }
 
        func bar(s32 arg) -> Foo { return Foo{ a: arg, b: arg }; }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "single field, explicit polymorph",
 
        "
 
        struct Foo<T>{ T field }
 
        func bar(s32 arg) -> Foo<s32> { return Foo<s32>{ field: arg }; }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "single field, implicit polymorph",
 
        "
 
        struct Foo<T>{ T field }
 
        func bar(s32 arg) -> s32 {
 
            auto thingo = Foo{ field: arg };
 
            return arg;
 
        }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "multiple fields, same explicit polymorph",
 
        "
 
        struct Pair<T1, T2>{ T1 first, T2 second }
 
        func bar(s32 arg) -> s32 {
 
            auto qux = Pair<s32, s32>{ first: arg, second: arg };
 
            return arg;
 
        }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "multiple fields, same implicit polymorph", 
 
        "
 
        struct Pair<T1, T2>{ T1 first, T2 second }
 
        func bar(s32 arg) -> s32 {
 
            auto wup = Pair{ first: arg, second: arg };
 
            return arg;
 
        }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "multiple fields, different explicit polymorph",
 
        "
 
        struct Pair<T1, T2>{ T1 first, T2 second }
 
        func bar(s32 arg1, s8 arg2) -> s32 {
 
            auto shoo = Pair<s32, s8>{ first: arg1, second: arg2 };
 
            return arg1;
 
        }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "multiple fields, different implicit polymorph",
 
        "
 
        struct Pair<T1, T2>{ T1 first, T2 second }
 
        func bar(s32 arg1, s8 arg2) -> s32 {
 
            auto shrubbery = Pair{ first: arg1, second: arg2 };
 
            return arg1;
 
        }
 
        "
 
    );
 
}
 

	
 
#[test]
 
fn test_incorrect_struct_instance() {
 
    Tester::new_single_source_expect_err(
 
        "reused field in definition",
 
        "struct Foo{ s32 a, s8 a }"
 
    ).error(|e| { e
 
        .assert_num(2)
 
        .assert_occurs_at(0, "a }")
 
        .assert_msg_has(0, "defined more than once")
 
        .assert_occurs_at(1, "a, ")
 
        .assert_msg_has(1, "other struct field");
 
    });
 

	
 
    Tester::new_single_source_expect_err(
 
        "reused field in instance",
 
        "
 
        struct Foo{ s32 a, s32 b }
 
        func bar() -> s32 {
 
            auto foo = Foo{ a: 5, a: 3 };
 
            return 0;
 
        }
 
        "
 
    ).error(|e| { e
 
        .assert_occurs_at(0, "a: 3")
 
        .assert_msg_has(0, "field is specified more than once");
 
    });
 

	
 
    Tester::new_single_source_expect_err(
 
        "missing field",
 
        "
 
        struct Foo { s32 a, s32 b }
 
        func bar() -> s32 {
 
            auto foo = Foo{ a: 2 };
 
            return 0;
 
        }
 
        "
 
    ).error(|e| { e
 
        .assert_occurs_at(0, "Foo{")
 
        .assert_msg_has(0, "'b' is missing");
 
    });
 

	
 
    Tester::new_single_source_expect_err(
 
        "missing fields",
 
        "
 
        struct Foo { s32 a, s32 b, s32 c }
 
        func bar() -> s32 {
 
            auto foo = Foo{ a: 2 };
 
            return 0;
 
        }
 
        "
 
    ).error(|e| { e
 
        .assert_occurs_at(0, "Foo{")
 
        .assert_msg_has(0, "[b, c] are missing");
 
    });
 
}
 

	
 
#[test]
 
fn test_correct_enum_instance() {
 
    Tester::new_single_source_expect_ok(
 
        "single variant",
 
        "
 
        enum Foo { A }
 
        func bar() -> Foo { return Foo::A; }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "multiple variants",
 
        "
 
        enum Foo { A=15, B = 0xF }
 
        func bar() -> Foo { auto a = Foo::A; return Foo::B; }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "explicit single polymorph",
 
        "
 
        enum Foo<T>{ A }
 
        func bar() -> Foo<s32> { return Foo::A; }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "explicit multi-polymorph",
 
        "
 
        enum Foo<A, B>{ A, B }
 
        func bar() -> Foo<s8, s32> { return Foo::B; }
 
        "
 
    );
 
}
 

	
 
#[test]
 
fn test_incorrect_enum_instance() {
 
    Tester::new_single_source_expect_err(
 
        "variant name reuse",
 
        "
 
        enum Foo { A, A }
 
        func bar() -> Foo { return Foo::A; }
 
        "
 
    ).error(|e| { e
 
        .assert_num(2)
 
        .assert_occurs_at(0, "A }")
 
        .assert_msg_has(0, "defined more than once")
 
        .assert_occurs_at(1, "A, ")
 
        .assert_msg_has(1, "other enum variant is defined here");
 
    });
 

	
 
    Tester::new_single_source_expect_err(
 
        "undefined variant",
 
        "
 
        enum Foo { A }
 
        func bar() -> Foo { return Foo::B; }
 
        "
 
    ).error(|e| { e
 
        .assert_num(1)
 
        .assert_msg_has(0, "variant 'B' does not exist on the enum 'Foo'");
 
    });
 
}
 

	
 
#[test]
 
fn test_correct_union_instance() {
 
    Tester::new_single_source_expect_ok(
 
        "single tag",
 
        "
 
        union Foo { A }
 
        func bar() -> Foo { return Foo::A; }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "multiple tags",
 
        "
 
        union Foo { A, B }
 
        func bar() -> Foo { return Foo::B; }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "single embedded",
 
        "
 
        union Foo { A(s32) }
 
        func bar() -> Foo { return Foo::A(5); }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "multiple embedded",
 
        "
 
        union Foo { A(s32), B(s8) }
 
        func bar() -> Foo { return Foo::B(2); }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "multiple values in embedded",
 
        "
 
        union Foo { A(s32, s8) }
 
        func bar() -> Foo { return Foo::A(0, 2); }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "mixed tag/embedded",
 
        "
 
        union OptionInt { None, Some(s32) }
 
        func bar() -> OptionInt { return OptionInt::Some(3); }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "single polymorphic var",
 
        "
 
        union Option<T> { None, Some(T) }
 
        func bar() -> Option<s32> { return Option::Some(3); }"
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "multiple polymorphic vars",
 
        "
 
        union Result<T, E> { Ok(T), Err(E), }
 
        func bar() -> Result<s32, s8> { return Result::Ok(3); }
 
        "
 
    );
 

	
 
    Tester::new_single_source_expect_ok(
 
        "multiple polymorphic in one variant",
 
        "
 
        union MaybePair<T1, T2>{ None, Some(T1, T2) }
 
        func bar() -> MaybePair<s8, s32> { return MaybePair::Some(1, 2); }
 
        "
 
    );
 
}
 

	
 
#[test]
 
fn test_incorrect_union_instance() {
 
    Tester::new_single_source_expect_err(
 
        "tag-variant name reuse",
 
        "
 
        union Foo{ A, A }
 
        "
 
    ).error(|e| { e
 
        .assert_num(2)
 
        .assert_occurs_at(0, "A }")
 
        .assert_msg_has(0, "union variant is defined more than once")
 
        .assert_occurs_at(1, "A, ")
 
        .assert_msg_has(1, "other union variant");
 
    });
 

	
 
    Tester::new_single_source_expect_err(
 
        "embedded-variant name reuse",
 
        "
 
        union Foo{ A(s32), A(s8) }
 
        "
 
    ).error(|e| { e 
 
        .assert_num(2)
 
        .assert_occurs_at(0, "A(s8)")
 
        .assert_msg_has(0, "union variant is defined more than once")
 
        .assert_occurs_at(1, "A(s32)")
 
        .assert_msg_has(1, "other union variant");
 
    });
 

	
 
    Tester::new_single_source_expect_err(
 
        "undefined variant",
 
        "
 
        union Silly{ Thing(s8) }
 
        func bar() -> Silly { return Silly::Undefined(5); }
 
        "
 
    ).error(|e| { e
 
        .assert_msg_has(0, "variant 'Undefined' does not exist on the union 'Silly'");
 
    });
 

	
 
    Tester::new_single_source_expect_err(
 
        "using tag instead of embedded",
 
        "
 
        union Foo{ A(s32) }
 
        func bar() -> Foo { return Foo::A; }
 
        "
 
    ).error(|e| { e
 
        .assert_msg_has(0, "variant 'A' of union 'Foo' expects 1 embedded values, but 0 were");
 
    });
 

	
 
    Tester::new_single_source_expect_err(
 
        "using embedded instead of tag",
 
        "
 
        union Foo{ A }
 
        func bar() -> Foo { return Foo::A(3); }
 
        "
 
    ).error(|e| { e 
 
        .assert_msg_has(0, "The variant 'A' of union 'Foo' expects 0");
 
    });
 

	
 
    Tester::new_single_source_expect_err(
 
        "wrong embedded value",
 
        "
 
        union Foo{ A(s32) }
 
        func bar() -> Foo { return Foo::A(false); }
 
        "
 
    ).error(|e| { e
 
        .assert_occurs_at(0, "Foo::A")
 
        .assert_msg_has(0, "failed to fully resolve")
 
        .assert_occurs_at(1, "false")
 
        .assert_msg_has(1, "has been resolved to 's32'")
 
        .assert_msg_has(1, "has been resolved to 'bool'");
 
    });
 
}
 

	
 
#[test]
 
fn test_correct_tuple_members() {
 
    // Tuples with zero members
 
    Tester::new_single_source_expect_ok(
 
        "single zero-tuple",
 
        "struct Foo{ () bar }"
 
    ).for_struct("Foo", |s| { s
 
        .for_field("bar", |f| { f.assert_parser_type("()"); })
 
        .assert_size_alignment("Foo", 0, 1);
 
    });
 

	
 
    Tester::new_single_source_expect_ok(
 
        "triple zero-tuple",
 
        "struct Foo{ () bar, () baz, () qux }"
 
    ).for_struct("Foo", |s| { s
 
        .assert_size_alignment("Foo", 0, 1);
 
    });
 

	
 
    // Tuples with one member (which are elided, because due to ambiguity
 
    // between a one-tuple literal and a parenthesized expression, we're not
 
    // going to be able to construct one-tuples).
 
    Tester::new_single_source_expect_ok(
 
        "single elided one-tuple",
 
        "struct Foo{ (u32) bar }"
 
    ).for_struct("Foo", |s| { s
 
        .for_field("bar", |f| { f.assert_parser_type("u32"); })
 
        .assert_size_alignment("Foo", 4, 4);
 
    });
 

	
 
    Tester::new_single_source_expect_ok(
 
        "triple elided one-tuple",
 
        "struct Foo{ (u8) bar, (u16) baz, (u32) qux }"
 
    ).for_struct("Foo", |s| { s
 
        .assert_size_alignment("Foo", 8, 4);
 
    });
 

	
 
    // Tuples with three members
 
    Tester::new_single_source_expect_ok(
 
        "single three-tuple",
 
        "struct Foo{ (u8, u16, u32) bar }"
 
    ).for_struct("Foo", |s| { s
 
        .for_field("bar", |f| { f.assert_parser_type("(u8,u16,u32)"); })
 
        .assert_size_alignment("Foo", 8, 4);
 
    });
 

	
 
    Tester::new_single_source_expect_ok(
 
        "double three-tuple",
 
        "struct Foo{ (u8,u16,u32,) bar, (s8,s16,s32,) baz }"
 
    ).for_struct("Foo", |s| { s
 
        .for_field("bar", |f| { f.assert_parser_type("(u8,u16,u32)"); })
 
        .for_field("baz", |f| { f.assert_parser_type("(s8,s16,s32)"); })
 
        .assert_size_alignment("Foo", 16, 4);
 
    });
 
}
 

	
 
#[test]
 
fn test_correct_tuple_polymorph_args() {
 
    todo!("write");
 
}
 

	
 
#[test]
 
fn test_incorrect_tuple_polymorph_args() {
 
    todo!("write");
 
}
 

	
 
#[test]
 
fn test_polymorph_array_types() {
 
    Tester::new_single_source_expect_ok(
 
        "array of polymorph in struct",
 
        "
 
        struct Foo<T> { T[] hello }
 
        struct Bar { Foo<u32>[] world }
 
        "
 
    ).for_struct("Bar", |s| { s
 
        .for_field("world", |f| { f.assert_parser_type("Foo<u32>[]"); });
 
    });
 

	
 
    Tester::new_single_source_expect_ok(
 
        "array of port in struct",
 
        "
 
        struct Bar { in<u32>[] inputs }
 
        "
 
    ).for_struct("Bar", |s| { s
 
        .for_field("inputs", |f| { f.assert_parser_type("in<u32>[]"); });
 
    });
 
}
 
\ No newline at end of file
0 comments (0 inline, 0 general)