Support compound statements

backend/riscv.cpp

@@ -57,6 +57,10 @@ namespace elna::riscv
         return reinterpret_cast<const std::byte *>(&this->representation) + sizeof(this->representation);
     }
 
+    void visitor::visit(source::declaration *declaration)
+    {
+    }
+
     void visitor::visit(source::definition *definition)
     {
         constants[definition->identifier()] = definition->body().number();
@@ -64,60 +68,40 @@ namespace elna::riscv
 
     void visitor::visit(source::block *block)
     {
+        this->instructions.push_back(instruction(base_opcode::opImm));
+        this->instructions.push_back(instruction(base_opcode::store));
+        this->instructions.push_back(instruction(base_opcode::store));
+        this->instructions.push_back(instruction(base_opcode::opImm));
+
         for (const auto& block_definition : block->definitions())
         {
             block_definition->accept(this);
         }
+        for (const auto& block_declaration : block->declarations())
+        {
+            block_declaration->accept(this);
+        }
         block->body().accept(this);
 
-        // Prologue.
-        const uint stackSize = static_cast<std::uint32_t>(variable_counter * 4 + 12);
-
-        std::vector<instruction> prologue{
-            instruction(base_opcode::opImm)
-                .i(x_register::sp, funct3_t::addi, x_register::sp, -stackSize),
-            instruction(base_opcode::store)
-                .s(stackSize - 4, funct3_t::sw, x_register::sp, x_register::s0),
-            instruction(base_opcode::store)
-                .s(stackSize - 8, funct3_t::sw, x_register::sp, x_register::ra),
-            instruction(base_opcode::opImm)
-                .i(x_register::s0, funct3_t::addi, x_register::sp, stackSize)
-        };
-        this->instructions.insert(this->instructions.cbegin(), prologue.begin(), prologue.end());
-
-        // Print the result.
-        this->instructions.push_back(instruction(base_opcode::opImm)
-            .i(x_register::a1, funct3_t::addi, x_register::a0, 0));
-        this->references[0] = reference();
-        this->references[0].name = ".CL0";
-        this->references[0].offset = instructions.size() * 4;
-        this->references[0].target = address_t::high20;
-        this->instructions.push_back(instruction(base_opcode::lui).u(x_register::a5, 0));
-        this->references[1] = reference();
-        this->references[1].name = ".CL0";
-        this->references[1].offset = instructions.size() * 4;
-        this->references[1].target = address_t::lower12i;
-
-        this->instructions.push_back(instruction(base_opcode::opImm)
-            .i(x_register::a0, funct3_t::addi, x_register::a5, 0));
-        this->references[2] = reference();
-        this->references[2].name = "printf";
-        this->references[2].offset = instructions.size() * 4;
-        this->references[2].target = address_t::text;
-        this->instructions.push_back(instruction(base_opcode::auipc).u(x_register::ra, 0));
-        this->instructions.push_back(instruction(base_opcode::jalr)
-            .i(x_register::ra, funct3_t::jalr, x_register::ra, 0));
         // Set the return value (0).
         this->instructions.push_back(instruction(base_opcode::op)
             .r(x_register::a0, funct3_t::_and, x_register::zero, x_register::zero));
 
+        // Prologue.
+        const uint stack_size = static_cast<std::uint32_t>(variable_counter * 4 + 12);
+
+        this->instructions[0].i(x_register::sp, funct3_t::addi, x_register::sp, -stack_size);
+        this->instructions[1].s(stack_size - 4, funct3_t::sw, x_register::sp, x_register::s0);
+        this->instructions[2].s(stack_size - 8, funct3_t::sw, x_register::sp, x_register::ra);
+        this->instructions[3].i(x_register::s0, funct3_t::addi, x_register::sp, stack_size);
+
         // Epilogue.
         this->instructions.push_back(instruction(base_opcode::load)
-            .i(x_register::s0, funct3_t::lw, x_register::sp, stackSize - 4));
+            .i(x_register::s0, funct3_t::lw, x_register::sp, stack_size - 4));
         this->instructions.push_back(instruction(base_opcode::load)
-            .i(x_register::ra, funct3_t::lw, x_register::sp, stackSize - 8));
+            .i(x_register::ra, funct3_t::lw, x_register::sp, stack_size - 8));
         this->instructions.push_back(instruction(base_opcode::opImm)
-                .i(x_register::sp, funct3_t::addi, x_register::sp, stackSize));
+            .i(x_register::sp, funct3_t::addi, x_register::sp, stack_size));
         this->instructions.push_back(instruction(base_opcode::jalr)
             .i(x_register::zero, funct3_t::jalr, x_register::ra, 0));
     }
@@ -125,6 +109,42 @@ namespace elna::riscv
     void visitor::visit(source::bang_statement *statement)
     {
         statement->body().accept(this);
+
+        // Print the result.
+        this->instructions.push_back(instruction(base_opcode::opImm)
+            .i(x_register::a1, funct3_t::addi, x_register::a0, 0));
+
+        this->references.push_back(reference());
+        this->references.back().name = ".CL0";
+        this->references.back().offset = instructions.size() * 4;
+        this->references.back().target = address_t::high20;
+        this->instructions.push_back(instruction(base_opcode::lui).u(x_register::a5, 0));
+        this->references.push_back(reference());
+        this->references.back().name = ".CL0";
+        this->references.back().offset = instructions.size() * 4;
+        this->references.back().target = address_t::lower12i;
+
+        this->instructions.push_back(instruction(base_opcode::opImm)
+            .i(x_register::a0, funct3_t::addi, x_register::a5, 0));
+        this->references.push_back(reference());
+        this->references.back().name = "printf";
+        this->references.back().offset = instructions.size() * 4;
+        this->references.back().target = address_t::text;
+        this->instructions.push_back(instruction(base_opcode::auipc).u(x_register::ra, 0));
+        this->instructions.push_back(instruction(base_opcode::jalr)
+            .i(x_register::ra, funct3_t::jalr, x_register::ra, 0));
+    }
+
+    void visitor::visit(source::compound_statement *statement)
+    {
+        for (auto& nested_statement : statement->statements())
+        {
+            nested_statement->accept(this);
+        }
+    }
+
+    void visitor::visit(source::assignment_statement *statement)
+    {
     }
 
     void visitor::visit(source::variable_expression *variable)

backend/target.cpp

@@ -32,8 +32,6 @@ namespace elna::riscv
 
         // Create string table writer
         ELFIO::string_section_accessor stra(str_sec);
-        // Add label name
-        ELFIO::Elf32_Word str_index = stra.add_string("msg");
 
         // Create read only data section
         ELFIO::section* ro_sec = writer.sections.add(".rodata");
@@ -50,15 +48,6 @@ namespace elna::riscv
         sym_sec->set_entry_size(writer.get_default_entry_size(ELFIO::SHT_SYMTAB));
         sym_sec->set_link(str_sec->get_index());
 
-        // Create symbol table writer
-        ELFIO::symbol_section_accessor syma(writer, sym_sec);
-        auto label_sym = syma.add_symbol(stra, ".CL0", 0x00000000, strlen("%d\n") + 1,
-                ELFIO::STB_LOCAL, ELFIO::STT_NOTYPE, 0, ro_sec->get_index());
-        syma.add_symbol(stra, "main", 0x00000000, instructions_size,
-                ELFIO::STB_GLOBAL, ELFIO::STT_FUNC, 0, text_sec->get_index());
-        auto printf_sym = syma.add_symbol(stra, "printf", 0x00000000, 0,
-                ELFIO::STB_GLOBAL, ELFIO::STT_NOTYPE, 0, ELFIO::SHN_UNDEF);
-
         // Create relocation table section
         ELFIO::section* rel_sec = writer.sections.add(".rel.text");
         rel_sec->set_type(ELFIO::SHT_REL);
@@ -68,15 +57,35 @@ namespace elna::riscv
         rel_sec->set_link(sym_sec->get_index());
         rel_sec->set_flags(ELFIO::SHF_ALLOC);
 
-        // Create relocation table writer
+        // Create symbol relocation table writers
+        ELFIO::symbol_section_accessor syma(writer, sym_sec);
         ELFIO::relocation_section_accessor rela(writer, rel_sec);
-        // Add relocation entry (adjust address at offset 11)
-        rela.add_entry(_visitor->references[0].offset, label_sym, 26 /* ELFIO::R_RISCV_HI20 */);
-        rela.add_entry(_visitor->references[0].offset, label_sym, 51 /* ELFIO::R_RISCV_RELAX */);
-        rela.add_entry(_visitor->references[1].offset, label_sym, 27 /* ELFIO::R_RISCV_LO12_I */);
-        rela.add_entry(_visitor->references[1].offset, label_sym, 51 /* ELFIO::R_RISCV_RELAX */);
-        rela.add_entry(_visitor->references[2].offset, printf_sym, 18 /* ELFIO::R_RISCV_CALL */);
-        rela.add_entry(_visitor->references[2].offset, printf_sym, 51 /* ELFIO::R_RISCV_RELAX */);
+        ELFIO::Elf_Word digit_symbol = syma.add_symbol(stra, ".CL0", 0x00000000, strlen("%d\n") + 1,
+                ELFIO::STB_LOCAL, ELFIO::STT_NOTYPE, 0, ro_sec->get_index());
+        ELFIO::Elf_Word printf_symbol = syma.add_symbol(stra, "printf", 0x00000000, 0,
+                ELFIO::STB_GLOBAL, ELFIO::STT_NOTYPE, 0, ELFIO::SHN_UNDEF);
+
+        for (auto& reference : _visitor->references)
+        {
+            // The loop assumes that address_t::lower12i always follows address_t::high20.
+            switch (reference.target)
+            {
+                case address_t::high20:
+                    rela.add_entry(reference.offset, digit_symbol, 26 /* ELFIO::R_RISCV_HI20 */);
+                    rela.add_entry(reference.offset, digit_symbol, 51 /* ELFIO::R_RISCV_RELAX */);
+                    break;
+                case address_t::lower12i:
+                    rela.add_entry(reference.offset, digit_symbol, 27 /* ELFIO::R_RISCV_LO12_I */);
+                    rela.add_entry(reference.offset, digit_symbol, 51 /* ELFIO::R_RISCV_RELAX */);
+                    break;
+                case address_t::text:
+                    rela.add_entry(reference.offset, printf_symbol, 18 /* ELFIO::R_RISCV_CALL */);
+                    rela.add_entry(reference.offset, printf_symbol, 51 /* ELFIO::R_RISCV_RELAX */);
+                    break;
+            }
+        }
+        syma.add_symbol(stra, "main", 0x00000000, instructions_size,
+                ELFIO::STB_GLOBAL, ELFIO::STT_FUNC, 0, text_sec->get_index());
 
         // Create ELF object file
         writer.save(out_file);

include/elna/backend/riscv.hpp

@@ -15,7 +15,7 @@ namespace elna::riscv
 
     struct reference
     {
-        const char* name;
+        std::string name;
         std::size_t offset;
         address_t target;
     };
@@ -141,6 +141,7 @@ namespace elna::riscv
 
     struct instruction
     {
+        instruction() = default; // NOP = addi x0, x0, 0.
         instruction(base_opcode opcode);
 
         instruction& i(x_register rd, funct3_t funct3, x_register rs1, std::uint32_t immediate);
@@ -155,17 +156,20 @@ namespace elna::riscv
         std::uint32_t representation{ 0 };
     };
 
-    class visitor : public source::parser_visitor
+    class visitor final : public source::parser_visitor
     {
     public:
         std::vector<instruction> instructions;
         bool register_in_use{ true };
         std::uint32_t variable_counter = 1;
-        reference references[3];
+        std::vector<reference> references;
         std::unordered_map<std::string, std::int32_t> constants;
 
+        virtual void visit(source::declaration *declaration) override;
         virtual void visit(source::definition *definition) override;
         virtual void visit(source::bang_statement *statement) override;
+        virtual void visit(source::compound_statement *statement) override;
+        virtual void visit(source::assignment_statement *statement) override;
         virtual void visit(source::block *block) override;
         virtual void visit(source::variable_expression *variable) override;
         virtual void visit(source::integer_literal *number) override;

include/elna/source/lexer.hpp

@@ -33,6 +33,7 @@ namespace elna::source
         text_iterator& operator++(int);
         bool operator==(const text_iterator& that) const noexcept;
         bool operator!=(const text_iterator& that) const noexcept;
+        text_iterator operator+(std::size_t step);
 
         friend std::pair<text_iterator, text_iterator> text_iterators(const std::string& buffer);
     };
@@ -50,19 +51,23 @@ namespace elna::source
          */
         enum class type : std::uint16_t
         {
-            number = 0,
-            term_operator = 1,
-            let = 2,
-            identifier = 3,
-            equals = 4,
-            var = 5,
-            semicolon = 6,
-            left_paren = 7,
-            right_paren = 8,
-            bang = 9,
-            dot = 10,
-            comma = 11,
-            factor_operator = 12,
+            number,
+            term_operator,
+            let,
+            identifier,
+            equals,
+            var,
+            semicolon,
+            left_paren,
+            right_paren,
+            bang,
+            dot,
+            comma,
+            factor_operator,
+            eof,
+            begin,
+            end,
+            assignment
         };
 
         /**
@@ -113,6 +118,16 @@ namespace elna::source
         std::string what() const override;
     };
 
+    class unexpected_token final : public error
+    {
+        token m_token;
+
+    public:
+        explicit unexpected_token(const token& token);
+
+        std::string what() const override;
+    };
+
     /**
      * Split the source into tokens.
      *

include/elna/source/parser.hpp

@@ -1,7 +1,9 @@
 #pragma once
 
+#include <boost/core/noncopyable.hpp>
 #include <cstdint>
 #include <memory>
+#include <optional>
 #include <elna/source/lexer.hpp>
 
 namespace elna::source
@@ -14,8 +16,11 @@ namespace elna::source
         division
     };
 
+    class declaration;
     class definition;
     class bang_statement;
+    class compound_statement;
+    class assignment_statement;
     class block;
     class binary_expression;
     class variable_expression;
@@ -23,8 +28,11 @@ namespace elna::source
 
     struct parser_visitor
     {
+        virtual void visit(declaration *) = 0;
         virtual void visit(definition *) = 0;
         virtual void visit(bang_statement *) = 0;
+        virtual void visit(compound_statement *) = 0;
+        virtual void visit(assignment_statement *) = 0;
         virtual void visit(block *) = 0;
         virtual void visit(binary_expression *) = 0;
         virtual void visit(variable_expression *) = 0;
@@ -48,6 +56,20 @@ namespace elna::source
     {
     };
 
+    /**
+     * Variable declaration.
+     */
+    class declaration : public node
+    {
+        std::string m_identifier;
+
+    public:
+        declaration(const std::string& identifier);
+        virtual void accept(parser_visitor *visitor) override;
+
+        std::string& identifier() noexcept;
+    };
+
     /**
      * Constant definition.
      */
@@ -57,7 +79,7 @@ namespace elna::source
         std::unique_ptr<integer_literal> m_body;
 
     public:
-        definition(std::string&& identifier, std::unique_ptr<integer_literal>&& body);
+        definition(const std::string& identifier, std::unique_ptr<integer_literal>&& body);
         virtual void accept(parser_visitor *visitor) override;
 
         std::string& identifier() noexcept;
@@ -75,6 +97,25 @@ namespace elna::source
         expression& body();
     };
 
+    class compound_statement : public statement
+    {
+        std::vector<std::unique_ptr<statement>> m_statements;
+
+    public:
+        compound_statement() = default;
+        compound_statement(std::vector<std::unique_ptr<statement>>&& statements);
+        virtual void accept(parser_visitor *visitor) override;
+
+        std::vector<std::unique_ptr<statement>>& statements();
+    };
+
+    class assignment_statement : public statement
+    {
+        std::unique_ptr<variable_expression> lvalue;
+        std::unique_ptr<expression> rvalue;
+        virtual void accept(parser_visitor *visitor) override;
+    };
+
     /**
      * Block.
      */
@@ -82,13 +123,17 @@ namespace elna::source
     {
         std::unique_ptr<statement> m_body;
         std::vector<std::unique_ptr<definition>> m_definitions;
+        std::vector<std::unique_ptr<declaration>> m_declarations;
 
     public:
-        block(std::vector<std::unique_ptr<definition>>&& definitions, std::unique_ptr<statement>&& body);
+        block(std::vector<std::unique_ptr<definition>>&& definitions,
+                std::vector<std::unique_ptr<declaration>>&& declarations,
+                std::unique_ptr<statement>&& body);
         virtual void accept(parser_visitor *visitor) override;
 
         statement& body();
         std::vector<std::unique_ptr<definition>>& definitions() noexcept;
+        std::vector<std::unique_ptr<declaration>>& declarations() noexcept;
     };
 
     class integer_literal : public expression
@@ -129,7 +174,7 @@ namespace elna::source
         binary_operator operation() const noexcept;
     };
 
-    struct parser
+    struct parser : boost::noncopyable
     {
         parser(const std::vector<token>& tokens);
 
@@ -140,11 +185,19 @@ namespace elna::source
         std::unique_ptr<expression> parse_term();
         std::unique_ptr<expression> parse_expression();
         std::unique_ptr<definition> parse_definition();
-        std::unique_ptr<statement> parse_bang_statement();
+        std::unique_ptr<declaration> parse_declaration();
+        std::unique_ptr<statement> parse_statement();
+        std::unique_ptr<bang_statement> parse_bang_statement();
+        std::unique_ptr<compound_statement> parse_compound_statement();
         std::vector<std::unique_ptr<definition>> parse_definitions();
+        std::vector<std::unique_ptr<declaration>> parse_declarations();
         std::unique_ptr<block> parse_block();
 
+        std::optional<std::reference_wrapper<const token>> advance(const token::type token_type);
+        bool skip(const token::type token_type);
+
         std::vector<token>::const_iterator tokens;
         std::vector<token>::const_iterator end;
+        std::list<std::unique_ptr<error>> errors;
     };
 }

include/elna/source/symboltable.hpp

@@ -6,6 +6,17 @@
 
 namespace elna::source
 {
+    class name_collision final : public error
+    {
+        position previous;
+        std::string name;
+
+    public:
+        name_collision(const std::string& name, const position current, const position previous);
+
+        std::string what() const override;
+    };
+
     class info
     {
     public:
@@ -27,8 +38,13 @@ namespace elna::source
 
     class variable_info final : public info
     {
+        std::size_t m_offset{ 0 };
+
     public:
+        variable_info(const std::size_t offset);
         ~variable_info() override;
+
+        std::size_t offset() const noexcept;
     };
 
     class symbol_table
@@ -44,8 +60,11 @@ namespace elna::source
 
     class name_analysis_visitor final : public source::parser_visitor
     {
+        void visit(declaration *declaration) override;
         void visit(definition *definition) override;
         void visit(bang_statement *statement) override;
+        void visit(compound_statement *statement) override;
+        void visit(assignment_statement *statement) override;
         void visit(block *block) override;
         void visit(integer_literal *number) override;
         void visit(variable_expression *variable) override;

source/lexer.cpp

@@ -58,6 +58,12 @@ namespace elna::source
         return *this;
     }
 
+    text_iterator text_iterator::operator+(std::size_t step)
+    {
+        auto result = *this;
+        return ++result;
+    }
+
     bool text_iterator::operator==(const text_iterator& that) const noexcept
     {
         return this->m_buffer == that.m_buffer;
@@ -309,6 +315,11 @@ namespace elna::source
 
                 tokens.emplace_back(token::type::factor_operator, _operator.c_str(), iterator.position());
             }
+            else if (*iterator == ':' && iterator + 1 != text_end && *(iterator + 1) == '=')
+            {
+                tokens.emplace_back(token::type::assignment, iterator.position());
+                ++iterator;
+            }
             else
             {
                 return source_result(unexpected_character{ std::string{ *iterator }, iterator.position() });

source/parser.cpp

@@ -175,6 +175,11 @@ namespace elna::source
         return m_statements;
     }
 
+    void assignment_statement::accept(parser_visitor *visitor)
+    {
+        visitor->visit(this);
+    }
+
     parser::parser(const std::vector<token>& tokens)
         : tokens(tokens.cbegin()), end(tokens.cend())
     {
@@ -323,16 +328,25 @@ namespace elna::source
         auto result = std::make_unique<compound_statement>();
         std::unique_ptr<statement> next_statement;
 
-        do
+        while ((next_statement = parse_statement()) != nullptr)
         {
-            if ((next_statement = parse_statement()) == nullptr)
-            {
-                return nullptr;
-            }
             result->statements().push_back(std::move(next_statement));
-        }
-        while (tokens->of() != token::type::end);
+
+            if (tokens->of() == token::type::semicolon)
+            {
                 ++tokens;
+            }
+            else if (tokens->of() == token::type::end)
+            {
+                ++tokens;
+                break;
+            }
+            else
+            {
+                errors.push_back(std::make_unique<unexpected_token>(*tokens));
+                break;
+            }
+        }
 
         return result;
     }

source/symboltable.cpp

@@ -82,6 +82,10 @@ namespace elna::source
     {
     }
 
+    void name_analysis_visitor::visit(assignment_statement *statement)
+    {
+    }
+
     void name_analysis_visitor::visit(block *block)
     {
     }

tests/declare_variable.eln

@@ -1,4 +1,5 @@
 var x;
 begin
+  x := 5;
   ! 5
 end.

tests/expectations/multiline_output.txt

@@ -0,0 +1,2 @@
+5
+7

tests/multiline_output.eln

@@ -0,0 +1,4 @@
+begin
+  ! 5;
+  ! 7
+end.