feat(furas): introduce global variables

Closes: #59

furas/examples/ops.furas

@@ -1,22 +1,24 @@
 func println $u32 = native println
 
+allocate uwu
+
 public func main = #main
 main:
     push $u32 0
-    store %0
+    storeg %uwu
 loop_header:
-    load %0
+    loadg %uwu
     push $u32 10
     ge
     jnz #loop_end
 loop_body:
-    load %0
+    loadg %uwu
     call $u32 println
 
-    load %0
+    loadg %uwu
     push $u32 1
     add
-    store %0
+    storeg %uwu
 
     jmp #loop_header
 loop_end:

furas/include/furas/token.hpp

@@ -23,12 +23,13 @@ struct token {
         Colon,  /**< `:` */
 
         // Keywords
-        Func,    /**< `func` keyword for defining functions. */
-        Type,    /**< `type` keyword for defining types. */
-        Native,  /**< `native` keyword for native functions. :v: */
-        Import,  /**< `import` keyword for importing functions and types. */
-        Public,  /**< `public` access specifier. */
-        Private, /**< `private` access specifier. */
+        Func,     /**< `func` keyword for defining functions. */
+        Type,     /**< `type` keyword for defining types. */
+        Native,   /**< `native` keyword for native functions. :v: */
+        Import,   /**< `import` keyword for importing functions and types. */
+        Public,   /**< `public` access specifier. */
+        Private,  /**< `private` access specifier. */
+        Allocate, /**< `allocate` keyword for global variables. */
 
         // Instructions
         Push,
@@ -56,6 +57,8 @@ struct token {
         Lenof,
         Load,
         Store,
+        LoadGlobal,
+        StoreGlobal,
         Call,
         Jmp,
         Jnz,

furas/src/gen.cpp

@@ -47,6 +47,8 @@ std::unordered_map<enum token::type, furvm::instruction_t> instructions = {
     { token::Lenof, furvm::instruction_t::Lengthof },
     { token::Load, furvm::instruction_t::Load },
     { token::Store, furvm::instruction_t::Store },
+    { token::LoadGlobal, furvm::instruction_t::LoadGlobal },
+    { token::StoreGlobal, furvm::instruction_t::StoreGlobal },
     { token::Call, furvm::instruction_t::Call },
     { token::Jmp, furvm::instruction_t::Jump },
     { token::Jnz, furvm::instruction_t::JumpNotZero },
@@ -72,6 +74,7 @@ const char* token_type(enum token::type type) {
     case token::Import: return "import";
     case token::Public: return "public";
     case token::Private: return "private";
+    case token::Allocate: return "allocate";
     case token::Push: return "push";
     case token::Array: return "array";
     case token::Get: return "get";
@@ -97,6 +100,8 @@ const char* token_type(enum token::type type) {
     case token::Lenof: return "lenof";
     case token::Load: return "load";
     case token::Store: return "store";
+    case token::LoadGlobal: return "loadg";
+    case token::StoreGlobal: return "storeg";
     case token::Call: return "call";
     case token::Jmp: return "jmp";
     case token::Jnz: return "jnz";
@@ -128,6 +133,7 @@ struct mod_context {
             pair_hash<std::string, furvm::function_sig, std::hash<std::string>, furvm::detail::function_sig_hash>>
                                                        functions;
     std::unordered_map<std::string, furvm::mod_type_h> types;
+    std::unordered_map<std::string, std::uint16_t>     variables;
 
     std::unordered_map<std::string, label_context> labels;
 
@@ -214,6 +220,15 @@ struct mod_context {
             return { generator_error::Success };
         }
 
+        case token::Allocate: {
+            result = eat_token(lexer, token::Identifier);
+            if (!result) return result.error;
+            std::string name = std::string(result->value.string);
+            variables.emplace(name, variables.size());
+            mod.set_global_variable_count(variables.size());
+            return { generator_error::Success };
+        }
+
         case token::Func:
         case token::Type:
         case token::Public:
@@ -465,6 +480,16 @@ struct mod_context {
                 if (!result) return result.error;
                 instr.arg.u16 = result->value.uint;
             } break;
+            case furvm::instruction_argument::GlobalVariable: {
+                result = eat_token(lexer, token::Percent);
+                if (!result) return result.error;
+                result = eat_token(lexer, token::Identifier);
+                if (!result) return result.error;
+                if (auto it = variables.find(std::string(result->value.string)); it != variables.end())
+                    instr.arg.u16 = it->second;
+                else
+                    throw std::runtime_error("Unknown global variable");
+            } break;
             case furvm::instruction_argument::Function: {
                 furvm::function_sig signature;
                 while ((result = next_token(lexer)).error.type == generator_error::Success &&

furas/src/lexer.cpp

@@ -39,6 +39,7 @@ token_r lexer::next_token() {
         { "import", token::Import },
         { "public", token::Public },
         { "private", token::Private },
+        { "allocate", token::Allocate },
 
         { "push", token::Push },
         { "array", token::Array },
@@ -65,6 +66,8 @@ token_r lexer::next_token() {
         { "lenof", token::Lenof },
         { "load", token::Load },
         { "store", token::Store },
+        { "loadg", token::LoadGlobal },
+        { "storeg", token::StoreGlobal },
         { "call", token::Call },
         { "jmp", token::Jmp },
         { "jnz", token::Jnz },

furvm/include/furvm/instruction.hpp

@@ -21,6 +21,7 @@ struct instruction_argument {
         Constant,
         Type,
         Variable,
+        GlobalVariable,
         Function,
         Offset,
 
@@ -78,6 +79,8 @@ struct instruction {
         Lengthof,
         Load,
         Store,
+        LoadGlobal,
+        StoreGlobal,
         Call,
         Jump,
         JumpNotZero,

furvm/include/furvm/module.hpp

@@ -6,10 +6,14 @@
 #include "furvm/function.hpp"
 #include "furvm/fwd.hpp"
 #include "furvm/handle.hpp"
+#include "furvm/thing.hpp"
 
 #include <functional>
 #include <istream>
+#include <limits>
+#include <optional>
 #include <ostream>
+#include <stdexcept>
 #include <string>
 #include <type_traits>
 #include <unordered_map>
@@ -348,6 +352,33 @@ public:
     }
 
     const handle_container<mod_type_h>& types() const { return m_types; }
+public:
+    void set_global_variable_count(std::uint16_t count) {
+        m_globalVariables.resize(count);
+        m_globalVariables.shrink_to_fit();
+    }
+
+    std::uint16_t get_global_variable_count() const { return static_cast<std::uint16_t>(m_globalVariables.size()); }
+
+    void store_global_variable(std::uint16_t var, thing<>&& thing) {
+        if (var >= m_globalVariables.size()) throw std::runtime_error("invalid slot");
+        m_globalVariables.emplace(m_globalVariables.cbegin() + var, std::move(thing));
+    }
+
+    void store_global_variable(std::uint16_t var, const thing<>& thing) {
+        if (var >= m_globalVariables.size()) throw std::runtime_error("invalid slot");
+        m_globalVariables.emplace(m_globalVariables.cbegin() + var, thing);
+    }
+
+    thing<>& load_global_variable(std::uint16_t var) {
+        if (var >= m_globalVariables.size()) throw std::runtime_error("invalid slot");
+        return m_globalVariables[var];
+    }
+
+    const thing<>& load_global_variable(std::uint16_t var) const {
+        if (var >= m_globalVariables.size()) throw std::runtime_error("invalid slot");
+        return m_globalVariables[var];
+    }
 public:
     /**
      * @brief Prints the module in a bytecode form to an output stream.
@@ -376,6 +407,8 @@ private:
 
     handle_container<mod_type_h> m_types;
 
+    std::vector<thing<>> m_globalVariables;
+
     std::unordered_map<std::string, native_function> m_nativeFunctions;
 };
 

furvm/src/executor.cpp

@@ -326,6 +326,12 @@ void executor::step() {
     case instruction_t::Store: {
         store_thing(instr.arg.u16, std::move(pop_thing()));
     } break;
+    case instruction_t::LoadGlobal: {
+        push_thing(make_reference(frame.mod->load_global_variable(instr.arg.u16)));
+    } break;
+    case instruction_t::StoreGlobal: {
+        frame.mod->store_global_variable(instr.arg.u16, std::move(pop_thing()));
+    } break;
     case instruction_t::Call: {
         push_frame(frame.mod, *frame.mod->function_at(instr.arg.u16));
     } break;

furvm/src/instruction.cpp

@@ -27,6 +27,8 @@ const std::size_t instruction_argument::s_sizes[instruction_argument::Count] = {
     4,
     // Variable:
     2,
+    // GlobalVariable:
+    2,
     // Function:
     4,
     // Offset:
@@ -54,6 +56,8 @@ const bool instruction_argument::s_signedness[instruction_argument::Count] = {
     false,
     // Variable:
     false,
+    // GlobalVariable:
+    false,
     // Function:
     false,
     // Offset:
@@ -125,6 +129,10 @@ const instruction_argument_t instruction::s_arguments[instruction::Count] = {
     instruction_argument::Variable,
     // Store:
     instruction_argument::Variable,
+    // LoadGlobal:
+    instruction_argument::GlobalVariable,
+    // StoreGlobal:
+    instruction_argument::GlobalVariable,
     // Call:
     instruction_argument::Function,
     // Jump:

furvm/src/module.cpp

@@ -88,6 +88,8 @@ std::ostream& mod::serialize(std::ostream& os) const {
         }
     }
 
+    detail::serialize(os, static_cast<std::uint16_t>(m_globalVariables.size()));
+
     detail::serialize(os, std::uint64_t(m_bytecode.size()));
     return os.write(reinterpret_cast<const char*>(m_bytecode.data()), static_cast<std::streamsize>(m_bytecode.size()));
 }
@@ -197,6 +199,10 @@ mod mod::load(std::istream& is) {
         }
     }
 
+    std::uint16_t globalVariables = 0;
+    detail::load(is, globalVariables);
+    mod.set_global_variable_count(globalVariables);
+
     std::uint64_t bytecodeLength = 0;
     detail::load(is, bytecodeLength);
     mod.bytecode().resize(bytecodeLength);