feat(furc): introduce function call expression and call instruction

furc/include/furc/ast/expression.hpp

@@ -4,6 +4,8 @@
 #include "furc/ast/node.hpp"
 #include "furc/ast/statement.hpp"
 
+#include <vector>
+
 namespace furc {
 namespace ast {
 
@@ -16,6 +18,7 @@ enum class expression_node_t {
     Unaryop,   /**< Unary operation expression */
     Binop,     /**< Binary operation expression */
     VarAssign, /**< Variable assignment expression */
+    FuncCall,  /**< Function call expression. */
 };
 
 /**
@@ -350,6 +353,54 @@ private:
     expression_node_p       m_rhs;
 };
 
+/**
+ * @brief Function call expression AST node.
+ */
+class function_call_expression_node final : public expression_node {
+public:
+    /**
+     * @brief Construct a new function call expression AST node.
+     *
+     * @param location Node location.
+     * @param func Left-hand-side expression.
+     * @param args Function arguments.
+     */
+    function_call_expression_node(struct location location,
+        expression_node_p&&                       func,
+        std::vector<expression_node_p>&&          args)
+      : expression_node(location), m_func(std::move(func)), m_args(std::move(args)) {}
+
+    /**
+     * @brief Returns this node's left-hand-side expression.
+     *
+     * @return The left-hand-side expression.
+     */
+    const expression_node_p& func() const { return m_func; }
+
+    /**
+     * @brief Returns this node's argument expressions.
+     *
+     * @return The argument expressions.
+     */
+    const std::vector<expression_node_p>& args() const { return m_args; }
+public:
+    /**
+     * @brief Returns this node's expression type.
+     *
+     * @return expression_node_t::FuncCall.
+     */
+    expression_node_t expression_type() const override { return expression_node_t::FuncCall; }
+public:
+    void accept(visitor& visitor) const override;
+
+    std::ostream& print(std::ostream& os) const override;
+protected:
+    bool equal(const node& rhs) const override;
+private:
+    expression_node_p              m_func;
+    std::vector<expression_node_p> m_args;
+};
+
 } // namespace ast
 } // namespace furc
 

furc/include/furc/ast/fwd.hpp

@@ -151,6 +151,14 @@ using var_assign_expression_node_p =
 using var_assign_expression_node_r =
     node_r<var_assign_expression_node>; /**< Alias for var_assign_expression_node result */
 
+class function_call_expression_node;
+
+using function_call_expression_node_p =
+    node_p<function_call_expression_node>; /**< Alias for a shared pointer to function_call_expression_node. */
+
+using function_call_expression_node_r =
+    node_r<function_call_expression_node>; /**< Alias for function_call_expression_node result. */
+
 /**
  * @brief List of statements.
  */

furc/include/furc/ast/visitor.hpp

@@ -82,6 +82,14 @@ public:
      */
     virtual void visit(const var_assign_expression_node& node) {}
 
+    /**
+     * @brief Visit a function_call_expression_node.
+     * @see function_call_expression_node
+     *
+     * @param node Node.
+     */
+    virtual void visit(const function_call_expression_node& node) {}
+
     /**
      * @brief Visit a function_declaration_node.
      * @see function_declaration_node

furc/include/furc/front/ir_generator.hpp

@@ -25,6 +25,7 @@ public:
     furlang::ir::mod&& move_module() { return std::move(m_module); }
 public:
     void visit(const ast::function_definition_node& funcDef) override;
+    void visit(const ast::function_declaration_node& funcDecl) override;
     void visit(const ast::return_statement_node& returnStmt) override;
     void visit(const ast::if_statement_node& node) override;
     void visit(const ast::while_statement_node& node) override;
@@ -35,6 +36,7 @@ public:
     void visit(const ast::unary_op_expression_node& node) override;
     void visit(const ast::binary_op_expression_node& node) override;
     void visit(const ast::var_assign_expression_node& node) override;
+    void visit(const ast::function_call_expression_node& node) override;
 private:
     template <typename T, typename... Args>
     void push(Args&&... args) {
@@ -45,7 +47,7 @@ private:
 
     furlang::ir::block_index push_block(bool validate = true);
 private:
-    furlang::ir::mod                    m_module;
+    furlang::ir::mod                       m_module;
     std::unique_ptr<furlang::ir::function> m_currentFunction;
     std::shared_ptr<furlang::ir::block>    m_currentBlock;
     ir_register                            m_registerCounter = 0;

furc/src/ast.cpp

@@ -108,6 +108,26 @@ bool var_assign_expression_node::equal(const node& rhsNode) const {
     return expression_node::equal(rhsNode) && m_compound == rhs.m_compound && m_lhs == rhs.m_lhs && m_rhs == rhs.m_rhs;
 }
 
+void function_call_expression_node::accept(visitor& visitor) const {
+    visitor.visit(*this);
+}
+
+std::ostream& function_call_expression_node::print(std::ostream& os) const {
+    os << *m_func << '(';
+    bool first = true;
+    for (const auto& arg : m_args) {
+        if (!first) os << ", ";
+        first = false;
+        os << *arg;
+    }
+    return os << ')';
+}
+
+bool function_call_expression_node::equal(const node& rhsNode) const {
+    const auto& rhs = dynamic_cast<const function_call_expression_node&>(rhsNode);
+    return expression_node::equal(rhsNode) && m_func == rhs.m_func && m_args == rhs.m_args;
+}
+
 bool declaration_node::equal(const node& rhs) const {
     return declaration_type() == dynamic_cast<const declaration_node&>(rhs).declaration_type();
 }

furc/src/back/furvm.cpp

@@ -100,7 +100,15 @@ void furvm_generator::generate_instruction(furvm::mod& mod,
             mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::ReturnValue));
         }
     } break;
-    case furlang::ir::instruction_t::Call:
+    case furlang::ir::instruction_t::Call: {
+        const auto& call = dynamic_cast<const furlang::ir::call_instruction&>(instr);
+
+        // TODO: Implement a queue for unknown functions
+        furvm::function_id func = mod.get_function_id(call.name());
+        mod.bytecode().push_back(static_cast<furvm::byte>(furvm::instruction_t::Call));
+        mod.bytecode().push_back((func >> 0) & 0xFF);
+        mod.bytecode().push_back((func >> 8) & 0xFF);
+    } break;
     case furlang::ir::instruction_t::Alloca: throw std::runtime_error("unimplemented instruction");
     case furlang::ir::instruction_t::Phi: throw std::runtime_error("unreachable");
     }

furc/src/front/ir_generator.cpp

@@ -167,6 +167,21 @@ void ir_generator::visit(const ast::var_assign_expression_node& node) {
     }
 }
 
+void ir_generator::visit(const ast::function_call_expression_node& node) {
+    std::vector<ir::operand> args;
+    args.reserve(node.args().size());
+    for (const auto& arg : node.args()) {
+        arg->accept(*this);
+        args.push_back(ir::operand::new_reg(m_registerCounter - 1));
+    }
+    if (node.func()->expression_type() != ast::expression_node_t::VarRead)
+        throw std::runtime_error("invalid function call left-hand-side expression");
+
+    push<ir::call_instruction>(dynamic_cast<const ast::var_read_expression_node&>(*node.func()).get_name(),
+        ir::operand::new_reg(m_registerCounter++),
+        std::move(args));
+}
+
 furlang::ir::block_index ir_generator::push_block(bool validate) {
     if (validate && !m_currentFunction->blocks().empty() && !m_currentFunction->blocks().back()->has_exit()) {
         throw std::runtime_error(

furc/src/front/parser.cpp

@@ -9,7 +9,6 @@
 #include "furc/front/token.hpp"
 
 #include <fstream>
-#include <iostream>
 #include <string>
 #include <unordered_map>
 #include <vector>
@@ -367,6 +366,7 @@ enum class rhsop_info_t {
     Unaryop,
     Binop,
     Assignment,
+    FuncCall,
 };
 
 struct rhsop_info {
@@ -379,6 +379,8 @@ struct rhsop_info {
         ast::binop_expression_node_t   assignment;
     };
 
+    bool has_rhs() const { return type == rhsop_info_t::Binop || type == rhsop_info_t::Assignment; }
+
     static rhsop_info create(ast::unaryop_expression_node_t type, std::uint32_t precedence) {
         rhsop_info info{};
         info.type          = rhsop_info_t::Unaryop;
@@ -407,6 +409,14 @@ struct rhsop_info {
         info.assignment    = compound;
         return info;
     }
+
+    static rhsop_info create_function_call() {
+        rhsop_info info{};
+        info.type          = rhsop_info_t::FuncCall;
+        info.precedence    = 1;
+        info.associativity = associativity::Left;
+        return info;
+    }
 };
 
 ast::expression_node_r parser::parse_expression_rhs(ast::expression_node_p&& init, std::uint32_t precedence) {
@@ -431,6 +441,7 @@ ast::expression_node_r parser::parse_expression_rhs(ast::expression_node_p&& ini
         { token_t::GreaterThan, rhsop_info::create(ast::binop_expression_node_t::GreaterThan, 9, associativity::Left) },
         { token_t::LessEq, rhsop_info::create(ast::binop_expression_node_t::LessEqual, 9, associativity::Left) },
         { token_t::GreaterEq, rhsop_info::create(ast::binop_expression_node_t::GreaterEqual, 9, associativity::Left) },
+        { token_t::LParen, rhsop_info::create_function_call() },
     };
 
     ast::expression_node_p lhs = std::move(init);
@@ -442,13 +453,28 @@ ast::expression_node_r parser::parse_expression_rhs(ast::expression_node_p&& ini
         if (current.precedence >= precedence) return lhs;
         auto opToken = next_token();
 
-        ast::expression_node_p rhs;
+        ast::expression_node_p              rhs;
-        if (current.type != rhsop_info_t::Unaryop) {
+        std::vector<ast::expression_node_p> params;
+        if (current.has_rhs()) {
             auto expr = parse_expression_unary(current.precedence + 1); // unary prefix is always right-associative
             if (expr.has_error()) {
                 return ast::expression_node_r(ast::error{ expr.error().location });
             }
             rhs = std::move(expr.value());
+        } else if (current.type == rhsop_info_t::FuncCall && peek_token().has_value()) {
+            if (peek_token()->type != token_t::RParen) {
+                while (true) {
+                    auto expr = parse_expression_unary(current.precedence + 1);
+                    if (expr.has_error()) {
+                        return ast::expression_node_r(ast::error{ expr.error().location });
+                    }
+                    params.emplace_back(std::move(expr.value()));
+
+                    if (eat_token(token_t::Comma).has_error()) break;
+                }
+            }
+            auto enclosing = eat_token(token_t::RParen);
+            if (enclosing.has_error()) return ast::expression_node_r(ast::error{ enclosing.error().location });
         }
 
         auto nextIt = s_rhsops.find(peek_token()->type);
@@ -485,6 +511,11 @@ ast::expression_node_r parser::parse_expression_rhs(ast::expression_node_p&& ini
                 std::move(lhs),
                 std::move(rhs));
             break;
+        case rhsop_info_t::FuncCall:
+            lhs = m_arena->allocate_shared<ast::function_call_expression_node>(opToken->location,
+                std::move(lhs),
+                std::move(params));
+            break;
         }
     }
     return lhs;

furlang/include/furlang/ir/instruction.hpp

@@ -7,6 +7,7 @@
 #include <optional>
 #include <ostream>
 #include <stdexcept>
+#include <string>
 #include <utility>
 #include <vector>
 
@@ -627,6 +628,76 @@ protected:
     }
 };
 
+/**
+ * @brief Function call instruction.
+ */
+class call_instruction final : public instruction {
+public:
+    template <typename NameFwd, typename ArgsFwd>
+    call_instruction(NameFwd&& name, operand&& dst, ArgsFwd&& args)
+      : m_name(std::forward<NameFwd>(name)), m_dst(std::move(dst)), m_args(std::forward<ArgsFwd>(args)) {}
+
+    ~call_instruction() override = default;
+
+    call_instruction(call_instruction&&) noexcept            = default;
+    call_instruction& operator=(call_instruction&&) noexcept = default;
+    call_instruction(const call_instruction&)                = delete;
+    call_instruction& operator=(const call_instruction&)     = delete;
+public:
+    /**
+     * @brief Returns this instruction's type.
+     *
+     * @return instruction_t::Call.
+     */
+    instruction_t type() const override { return instruction_t::Call; }
+
+    bool has_destination() const override { return true; }
+
+    /**
+     * @brief Returns this instruction's destination register.
+     *
+     * @return The register.
+     */
+    operand& destination() override { return m_dst; }
+
+    /**
+     * @brief Returns this instruction's destination register.
+     *
+     * @return The register.
+     */
+    const operand& destination() const override { return m_dst; }
+
+    std::vector<const operand*> sources() const override {
+        std::vector<const operand*> srcs;
+        srcs.reserve(m_args.size());
+        for (const auto& op : m_args)
+            srcs.push_back(&op);
+        return srcs;
+    }
+
+    /**
+     * @brief Returns this instruction's callee name.
+     *
+     * @return The name.
+     */
+    const std::string& name() const { return m_name; }
+private:
+    std::string          m_name;
+    operand              m_dst;
+    std::vector<operand> m_args;
+protected:
+    std::ostream& print(std::ostream& os) const override {
+        os << "call " << m_name << '(';
+        bool first = true;
+        for (const auto& op : m_args) {
+            if (!first) os << ", ";
+            first = false;
+            os << op;
+        }
+        return os << ") = " << m_dst;
+    }
+};
+
 } // namespace ir
 } // namespace furlang