Method parse_elemsection

src/lib/parse/ParseContext.cpp:883–946

}

void ParseContext::parse_elemsection() {
    tok_.expect(TokenType::LParen);
    tok_.expect_keyword("elem");
    index_t elem_idx = module_.elems.size();
    // optional Id
    if (tok_.peek().type == TokenType::Id) {
        std::string id = tok_.consume().text;
        if (elem_map_.contains(id))
            throw Exception::Parse("duplicated elem id '" + id + "'", tok_.location());
        elem_map_[id] = elem_idx;
    }

    WasmElem& elem = module_.elems.emplace_back();

    // Detect form:
    // 1. Active with offset: tableuse? '(' ('offset'|) constexpr ')' ...
    // 2. declare elemlist
    // 3. passive elemlist
    // 4. Active with just funcidx* (legacy): '(' 'offset'? constexpr ')' funcidx*

    // Check for '(' 'table' ... ')' tableuse
    if (tok_.peek().type == TokenType::LParen &&
        tok_.peek2().type == TokenType::Keyword && tok_.peek2().text == "table") {
        // tableuse
        tok_.consume(); tok_.consume(); // '(' 'table'
        elem.mode.tableidx = parse_tableidx();
        tok_.expect(TokenType::RParen);
    }

    // Check for '(' ('offset'|constexpr-keyword) ... ')' — active
    if (tok_.peek().type == TokenType::LParen &&
        tok_.peek2().type == TokenType::Keyword &&
        (tok_.peek2().text == "offset" ||
         tok_.peek2().text == "i32.const" || tok_.peek2().text == "i64.const" ||
         tok_.peek2().text == "f32.const" || tok_.peek2().text == "f64.const" ||
         tok_.peek2().text == "ref.null" || tok_.peek2().text == "ref.func" ||
         tok_.peek2().text == "global.get")) {
        elem.mode.type = WasmElem::ElemMode::Mode::active;
        tok_.consume(); // '('
        if (tok_.peek_keyword("offset")) tok_.consume(); // 'offset'
        elem.mode.offset = parse_constexpr();
        tok_.expect(TokenType::RParen);
        if (!elem.mode.tableidx.has_value()) elem.mode.tableidx = 0;
        // funcidx* (legacy form)
        if (tok_.peek().type == TokenType::Integer || tok_.peek().type == TokenType::Id) {
            elem.type = RefType::funcref;
            while (tok_.peek().type == TokenType::Integer || tok_.peek().type == TokenType::Id) {
                elem.elemlist.push_back(ConstInstr{Instr::Ref_func(parse_funcidx())});
            }
            tok_.expect(TokenType::RParen);
            return;
        }
    } else if (tok_.peek_keyword("declare")) {
        tok_.consume();
        elem.mode.type = WasmElem::ElemMode::Mode::declarative;
    } else {
        elem.mode.type = WasmElem::ElemMode::Mode::passive;
    }