chore: flat out the file structure

Closes: #61

.clang-tidy

@@ -17,6 +17,7 @@ Checks: >
   -readability-redundant-access-specifiers,
   -readability-use-anyofallof,
   -readability-named-parameter,
+  -readability-convert-member-functions-to-static,
   -performance-enum-size,
   -cppcoreguidelines-avoid-magic-numbers,
   -cppcoreguidelines-pro-bounds-pointer-arithmetic,
@@ -33,7 +34,8 @@ Checks: >
   -cppcoreguidelines-pro-bounds-array-to-pointer-decay,
   -cppcoreguidelines-use-enum-class,
   -bugprone-forward-declaration-namespace,
-  -bugprone-tagged-union-member-count
+  -bugprone-tagged-union-member-count,
+  -bugprone-unchecked-optional-access
 
 WarningsAsErrors: "*"
 

.gitmodules

@@ -1,3 +1,3 @@
-[submodule "furdb/deps/isocline"]
+[submodule "deps/isocline"]
-	path = furdb/deps/isocline
+	path = deps/isocline
 	url = https://github.com/daanx/isocline

CMakeLists.txt

@@ -11,12 +11,16 @@ find_package(Doxygen)
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-add_subdirectory(furlang)
+add_subdirectory(src/furlang)
-add_subdirectory(furvm)
+add_subdirectory(src/furvm)
-add_subdirectory(furc)
+add_subdirectory(src/furc)
-add_subdirectory(furas)
+add_subdirectory(src/furas)
-add_subdirectory(disfuras)
+add_subdirectory(src/disfuras)
-add_subdirectory(furdb)
+add_subdirectory(src/furdb)
+
+# Dependencies
+set(IC_USE_CXX ON)
+add_subdirectory(${CMAKE_SOURCE_DIR}/deps/isocline)
 
 if(DOXYGEN_FOUND)
     set(DOXYGEN_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/docs)

disfuras/CMakeLists.txt

@@ -1,5 +0,0 @@
-file(GLOB_RECURSE DISFURAS_SRCS "src/**.cpp")
-file(GLOB_RECURSE DISFURAS_HDRS "include/**.hpp")
-add_executable(disfuras ${DISFURAS_SRCS} ${DISFURAS_HDRS})
-target_include_directories(disfuras PRIVATE include/)
-target_link_libraries(disfuras PUBLIC furlang libfurc libfurvm)

examples/furas/array2.furas

@@ -1,6 +1,7 @@
 type arr = array $s8 10
+type arrSlice = slice $s8
 
-func println ref $arr = native println
+func println $arrSlice = native println
 
 public func main = #main
 main:
@@ -30,5 +31,8 @@ body:
 end:
     drop
     load %0
-    call ref $arr println
+    push $u32 0
+    load %1
+    slice
+    call $arrSlice println
     ret

furas/CMakeLists.txt

@@ -1,5 +0,0 @@
-file(GLOB_RECURSE FURAS_SRCS "src/**.cpp")
-file(GLOB_RECURSE FURAS_HDRS "include/**.hpp")
-add_executable(furas ${FURAS_SRCS} ${FURAS_HDRS})
-target_include_directories(furas PUBLIC include/)
-target_link_libraries(furas PRIVATE furlang libfurvm)

furc/CMakeLists.txt

@@ -1,16 +0,0 @@
-file(GLOB_RECURSE FURC_SRCS "src/**.cpp")
-file(GLOB_RECURSE FURC_HDRS "include/**.hpp")
-add_library(libfurc ${FURC_SRCS} ${FURC_HDRS})
-target_include_directories(libfurc PUBLIC include/)
-target_compile_definitions(libfurc PRIVATE LIBFURC)
-set_target_properties(libfurc PROPERTIES PREFIX "")
-target_link_libraries(libfurc PUBLIC furlang libfurvm)
-add_executable(furc src/main.cpp)
-target_link_libraries(furc PRIVATE libfurc)
-
-include(GoogleTest)
-
-file(GLOB_RECURSE FURC_TESTS "test/**.cpp")
-add_executable(furc_tests ${FURC_TESTS})
-target_link_libraries(furc_tests PRIVATE libfurc GTest::gtest_main)
-# gtest_discover_tests(furc_tests)

furc/include/furc/middle/ssa.hpp

@@ -1,17 +0,0 @@
-#ifndef FURC_MIDDLE_SSA_HPP
-#define FURC_MIDDLE_SSA_HPP
-
-#include "furc/middle/ir.hpp"
-
-namespace furc {
-
-class ssa {
-    ssa() = delete;
-public:
-    static void process(ir_module& mod);
-    static void destruct(ir_module& mod);
-};
-
-} // namespace furc
-
-#endif // FURC_MIDDLE_SSA_HPP

furc/src/middle/ssa.cpp

@@ -1,130 +0,0 @@
-/**
- * Sources:
- *  - Practical Improvements to the Construction and Deconstruction of Static Single Assignment Form:
- * https://web.archive.org/web/20100607003509/http://www.cs.rice.edu/~harv/my_papers/ssa.pdf
- *  - A Simple, Fast Dominance Algorithm:
- * https://www.researchgate.net/publication/2569680_A_Simple_Fast_Dominance_Algorithm
- */
-
-#include "furc/middle/ssa.hpp"
-
-#include "furc/middle/ir.hpp"
-
-#include <algorithm>
-#include <cstddef>
-#include <stdexcept>
-#include <unordered_set>
-#include <vector>
-
-namespace furc {
-
-namespace {
-
-struct block_info {
-    std::size_t order = 0;
-
-    std::unordered_set<std::size_t> preds;
-    std::unordered_set<std::size_t> sucs;
-    std::size_t                     idom = 0;
-};
-
-void rpo_dfs(std::unordered_set<std::size_t>& visited,
-    std::vector<std::size_t>&                 order,
-    std::size_t                               block,
-    std::vector<block_info>&                  blocks) {
-    visited.insert(block);
-    for (auto succ : blocks[block].sucs) {
-        if (visited.find(succ) != visited.end()) continue;
-        rpo_dfs(visited, order, succ, blocks);
-    }
-    order.push_back(block);
-}
-
-void compute_rpo(std::vector<block_info>& blocks, std::vector<std::size_t>& order) {
-    std::unordered_set<std::size_t> visited;
-    if (!blocks.empty()) rpo_dfs(visited, order, 0, blocks);
-    std::reverse(order.begin(), order.begin());
-    for (std::size_t i = 0; i < order.size(); ++i) {
-        blocks[order[i]].order = i;
-    }
-}
-
-std::size_t intersect(std::vector<block_info>& blocks, std::size_t b1, std::size_t b2) {
-    std::size_t finger1 = b1;
-    std::size_t finger2 = b2;
-    while (finger1 != finger2) {
-        while (finger1 < finger2)
-            finger1 = blocks[finger1].idom;
-        while (finger2 < finger1)
-            finger2 = blocks[finger2].idom;
-    }
-    return finger1;
-}
-
-void process_function(ir_function& func) {
-    std::vector<block_info> blocks(func.blocks.size());
-
-    // 1. Compute CFG
-    for (std::size_t i = 0; i < func.blocks.size(); ++i) {
-        const auto& block = func.blocks[i];
-        if (block.instructions.empty()) continue;
-
-        const auto& termInstr = block.instructions.back();
-        switch (termInstr.type) {
-        case ir_instruction::Branch: {
-            const auto& src = termInstr.sources.front();
-            if (src.type != ir_operand::Block) throw std::runtime_error("invalid operand");
-            blocks[src.value.block].preds.insert(i);
-            blocks[i].sucs.insert(src.value.block);
-        } break;
-        case ir_instruction::BranchCond: {
-            const auto& src = termInstr.sources.front();
-            if (src.type != ir_operand::Block) throw std::runtime_error("invalid operand");
-            blocks[src.value.blockPair.first].preds.insert(i);
-            blocks[src.value.blockPair.second].preds.insert(i);
-            blocks[i].preds.insert(src.value.blockPair.first);
-            blocks[i].preds.insert(src.value.blockPair.second);
-        } break;
-        default: break;
-        }
-    }
-
-    // 2. Computing dominance tree
-    std::vector<std::size_t> order;
-    order.reserve(blocks.size());
-    compute_rpo(blocks, order);
-
-    blocks[order.front()].idom = order.front();
-
-    bool changed = true;
-    while (changed) {
-        changed = false;
-
-        for (std::size_t i = 1; i < order.size(); ++i) {
-            auto&       block   = blocks[order[i]];
-            std::size_t newIdom = -1;
-            bool        found   = false;
-            for (auto pred : block.preds) {
-                if (blocks[pred].idom == -1) continue;
-                newIdom = found ? intersect(blocks, pred, newIdom) : pred;
-                found   = true;
-            }
-
-            if (block.idom != newIdom) {
-                block.idom = newIdom;
-                changed    = true;
-            }
-        }
-    }
-}
-
-} // namespace
-
-void ssa::process(ir_module& mod) {
-    for (auto* func : mod.functions)
-        process_function(*func);
-}
-
-void ssa::destruct(ir_module& mod) {}
-
-} // namespace furc

furdb/CMakeLists.txt

@@ -1,8 +0,0 @@
-set(IC_USE_CXX ON)
-add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/deps/isocline)
-
-file(GLOB_RECURSE FURDB_SRCS "src/**.cpp")
-file(GLOB_RECURSE FURDB_HDRS "include/**.hpp")
-add_executable(furdb ${FURDB_SRCS} ${FURDB_HDRS})
-target_include_directories(furdb PRIVATE include/)
-target_link_libraries(furdb PUBLIC furlang libfurc libfurvm isocline)

furlang/CMakeLists.txt

@@ -1,4 +0,0 @@
-file(GLOB_RECURSE FURLANG_SRCS "src/**.cpp")
-file(GLOB_RECURSE FURLANG_HDRS "include/**.hpp")
-add_library(furlang STATIC ${FURLANG_SRCS} ${FURLANG_HDRS})
-target_include_directories(furlang PUBLIC include/)

furvm/include/furvm/constant.hpp

@@ -1,76 +0,0 @@
-#ifndef FURVM_CONSTANT_HPP
-#define FURVM_CONSTANT_HPP
-
-#include "furvm/exceptions.hpp"
-#include "furvm/fwd.hpp"
-
-#include <string_view>
-
-namespace furvm {
-
-enum class constant_t : std::uint8_t {
-    String, /**< String constant. */
-};
-
-class constant {
-public:
-    using string_type = std::string_view; /**< String constant type. */
-public:
-    /**
-     * @brief Construct a new string constant.
-     *
-     * @param string String.
-     */
-    constant(string_type string)
-      : m_type(constant_t::String), m_value(string) {}
-
-    ~constant() = default;
-
-    /**
-     * @brief Move constructor.
-     */
-    constant(constant&&) = default;
-
-    /**
-     * @brief Move constructor.
-     */
-    constant& operator=(constant&&) = default;
-
-    constant(const constant&)            = delete;
-    constant& operator=(const constant&) = delete;
-public:
-    /**
-     * @brief Returns this constant's type.
-     * @see constant_t
-     *
-     * @return The constant type.
-     */
-    constexpr constant_t type() const { return m_type; }
-
-    /**
-     * @brief Returns this constant's string value.
-     * @throws bad_constant_access if this constant's type is not constant_t::String.
-     *
-     * @return The string value.
-     */
-    constexpr string_type string() const {
-        require_type(constant_t::String);
-        return m_value.string;
-    }
-private:
-    void require_type(constant_t type) const {
-        if (m_type != type) throw bad_constant_access();
-    }
-private:
-    constant_t m_type{};
-    union value {
-        string_type string;
-
-        value(string_type sv)
-          : string(sv) {}
-    } m_value;
-};
-
-} // namespace furvm
-
-#endif // FURVM_CONSTANT_HPP

furvm/test/test.cpp

@@ -1,26 +0,0 @@
-#include "furlang/arena.hpp"
-#include "furvm/furvm.hpp"
-#include "furvm/thing.hpp"
-
-#include "gtest/gtest.h" // IWYU pragma: keep
-
-namespace {
-
-// TODO: Basic program tests (e.g. for loops)
-
-TEST(Things, Ops) {
-    furlang::arena arena;
-
-    furvm::thing lhs{ furvm::thing_type{ furvm::thing_type::U32 } };
-    lhs.get<furvm::thing_type::u32>() = 6;
-    furvm::thing rhs{ furvm::thing_type{ furvm::thing_type::U32 } };
-    rhs.get<furvm::thing_type::u32>() = 7;
-
-    auto res = lhs.add(rhs);
-    ASSERT_EQ(res.type().type, furvm::thing_type::U32);
-    EXPECT_EQ(lhs.get<furvm::thing_type::u32>(), 6);
-    EXPECT_EQ(rhs.get<furvm::thing_type::u32>(), 7);
-    EXPECT_EQ(res.get<furvm::thing_type::u32>(), 6 + 7);
-}
-
-} // namespace

include/furas/lexer.hpp

@@ -24,7 +24,7 @@ struct lexer_error {
     std::string    message;
 };
 
-using token_r = furlang::result<token, lexer_error>;
+using token_r = furlang::result<lexer_error, token>;
 
 class lexer {
 public:

include/furas/token.hpp

@@ -34,6 +34,7 @@ struct token {
         // Instructions
         Push,
         Array,
+        Slice,
         Get,
         Set,
         Drop,

include/furc/back/furvm/target.hpp

@@ -0,0 +1,16 @@
+#ifndef FURC_BACK_FURVM_HPP
+#define FURC_BACK_FURVM_HPP
+
+#include "furc/middle/ir.hpp"
+#include "furvm/module.hpp"
+
+namespace furc {
+
+class furvm_generator final {
+public:
+    static furvm::mod generate(const ir_module& mod);
+};
+
+} // namespace furc
+
+#endif // FURC_BACK_FURVM_HPP

include/furc/middle/ir.hpp

@@ -9,6 +9,7 @@
 #include <initializer_list>
 #include <optional>
 #include <stack>
+#include <stdexcept>
 #include <string>
 #include <type_traits>
 #include <unordered_map>
@@ -33,6 +34,16 @@ struct ir_operand {
         struct register_s {
             std::uint64_t name : 54;
             std::uint64_t ver : 10;
+
+            register_s() = default;
+
+            register_s(std::uint64_t id)
+              : name((id >> 10) & ((1ULL << 54) - 1)), ver((id >> 0) & ((1 << 10) - 1)) {}
+
+            register_s(std::uint64_t name, std::uint64_t ver)
+              : name(name), ver(ver) {}
+
+            operator std::uint64_t() const { return name << 10 | ver; }
         } reg;
         std::uint16_t variable;
         std::uint16_t global;
@@ -55,6 +66,9 @@ struct ir_operand {
         value_u(std::uint16_t variable)
           : variable(variable) {}
 
+        value_u(register_s reg)
+          : reg(reg) {}
+
         value_u(std::uint64_t first, std::uint64_t second)
           : blockPair({ first, second }) {}
 
@@ -65,6 +79,30 @@ struct ir_operand {
     template <typename... Args, typename = std::enable_if_t<std::is_constructible_v<value_u, Args...>>>
     ir_operand(type_e type, Args&&... args)
       : type(type), value(std::forward<Args>(args)...) {}
+
+    static ir_operand reg(std::uint64_t name, std::uint64_t ver) {
+        return { Register, value_u::register_s{ name, ver } };
+    }
+
+    bool operator==(const ir_operand& rhs) const {
+        if (type != rhs.type) return false;
+        switch (type) {
+        case Integer: return value.integer == rhs.value.integer;
+        case Register: return value.reg.name == rhs.value.reg.name && value.reg.ver == rhs.value.reg.ver;
+        case Variable: return value.variable == rhs.value.variable;
+        case Global: return value.global == rhs.value.global;
+        case Function: return value.function == rhs.value.function;
+        case Block: return value.block == rhs.value.block;
+        case BlockPair:
+            return value.blockPair.first == rhs.value.blockPair.first &&
+                   value.blockPair.second == rhs.value.blockPair.second;
+        case PhiPair:
+            return value.phiPair.block == rhs.value.phiPair.block &&
+                   value.phiPair.reg.name == rhs.value.phiPair.reg.name &&
+                   value.phiPair.reg.ver == rhs.value.phiPair.reg.ver;
+        }
+        throw std::runtime_error("unreachable");
+    }
 };
 
 struct ir_type {
@@ -139,6 +177,10 @@ struct ir_instruction {
         default: return false;
         }
     }
+
+    bool operator==(const ir_instruction& rhs) const {
+        return type == rhs.type && destination == rhs.destination && sources == rhs.sources;
+    }
 };
 
 struct ir_basic_block {
@@ -225,9 +267,10 @@ struct ir_function : ir_scope {
     std::vector<ir_basic_block> blocks;
 
     std::uint64_t regCount = 0;
+    std::uint64_t varCount = 0;
 
     const ir_variable* allocate(furlang::arena& arena, const std::string& name, ir_type type) final {
-        return variables[name] = arena.allocate<ir_function_variable>(type, regCount++);
+        return variables[name] = arena.allocate<ir_function_variable>(type, varCount++);
     }
 
     static ir_function from_name(std::string&& name) {
@@ -304,7 +347,11 @@ struct ir_context {
 
     void terminate() { add_instr(ir_instruction::Return); }
 
-    void terminate(ir_operand value) { add_instr(ir_instruction::Return, value); }
+    void terminate(ir_operand value) {
+        ir_instruction instr = { ir_instruction::Return };
+        instr.sources.emplace_back(value);
+        add_instr(std::move(instr));
+    }
 
     void terminate(std::uint64_t block) { add_instr(ir_instruction::Branch, ir_operand{ ir_operand::Block, block }); }
 

include/furc/middle/reg_gen.hpp

@@ -0,0 +1,177 @@
+/**
+ * SSA destruction (out-of-SSA phase) for register-based targets based on "Mechanizing Conventional SSA for a
+ * Verified Destruction with Coalescing" by Delphine Demange and Yon Fernandez de Retana
+ * (https://dl.acm.org/doi/pdf/10.1145/2892208.2892222 09/11/2026).
+ */
+#ifndef FURC_MIDDLE_REG_GEN_HPP
+#define FURC_MIDDLE_REG_GEN_HPP
+
+#include "furc/middle/ir.hpp"
+#include "furc/middle/ssa.hpp"
+
+#include <cassert>
+#include <cstdint>
+#include <unordered_set>
+#include <vector>
+
+namespace furc {
+
+class reg_gen {
+public:
+    class disjoint_set {
+    public:
+        std::uint64_t find(std::uint64_t var) {
+            if (m_parents.find(var) == m_parents.end()) m_parents.emplace(var, var);
+            if (m_parents[var] == var) return var;
+            return find(m_parents[var]);
+        }
+
+        void unite(std::uint64_t var1, std::uint64_t var2) {
+            std::uint64_t rep1 = find(var1);
+            std::uint64_t rep2 = find(var2);
+            if (rep1 != rep2) m_parents[rep1] = rep2;
+        }
+    private:
+        std::unordered_map<std::uint64_t, std::uint64_t> m_parents;
+    };
+public:
+    struct block_info {
+        std::unordered_set<std::uint64_t> defs;
+        std::unordered_set<std::uint64_t> uses;
+        std::unordered_set<std::uint64_t> liveIn;
+        std::unordered_set<std::uint64_t> liveOut;
+    };
+public:
+    reg_gen(ir_function& func, ssa& ssa) {
+        std::vector<block_info> lifeBlocks;
+        live_analysis(lifeBlocks, func.blocks, ssa.cfgBlocks);
+        remove_interference(func.blocks, lifeBlocks);
+        merge(func.blocks);
+    }
+public:
+    static void live_analysis(std::vector<block_info>& lifeBlocks,
+        const std::vector<ir_basic_block>&             irBlocks,
+        const std::vector<ssa::cfg_block>&             cfgBlocks) {
+        lifeBlocks.resize(irBlocks.size());
+        for (std::uint64_t i = 0; i < irBlocks.size(); ++i) {
+            const auto& irBlock = irBlocks[i];
+            auto&       block   = lifeBlocks[i];
+
+            for (const auto& instr : irBlock.instructions) {
+                for (const auto& op : instr.sources) {
+                    if (op.type != ir_operand::Register) continue;
+                    if (block.defs.find(op.value.reg) != block.defs.end()) continue;
+                    block.uses.insert(op.value.reg);
+                }
+
+                if (!instr.destination.has_value() || instr.destination->type != ir_operand::Register) continue;
+                block.defs.insert(instr.destination->value.reg);
+            }
+        }
+
+        bool changed = true;
+        while (changed) {
+            changed = false;
+
+            for (std::uint64_t i = 0; i < irBlocks.size(); ++i) {
+                const auto& irBlock = irBlocks[i];
+                auto&       block   = lifeBlocks[i];
+
+                std::unordered_set<std::uint64_t> newSet;
+                for (auto succ : cfgBlocks[i].sucs) {
+                    newSet.insert(lifeBlocks[succ].liveIn.begin(), lifeBlocks[succ].liveIn.end());
+                }
+
+                if (newSet != block.liveOut) {
+                    block.liveOut = newSet;
+                    changed       = true;
+                }
+
+                newSet.clear();
+                newSet.insert(block.uses.begin(), block.uses.end());
+                for (const auto& var : block.liveOut) {
+                    if (block.defs.find(var) != block.defs.end()) continue;
+                    newSet.insert(var);
+                }
+
+                if (newSet != block.liveIn) {
+                    block.liveIn = newSet;
+                    changed      = true;
+                }
+            }
+        }
+    }
+
+    static void remove_interference(std::vector<ir_basic_block>& irBlocks, const std::vector<block_info>& lifeBlocks) {
+        for (std::uint64_t i = 0; i < irBlocks.size(); ++i) {
+            auto& irBlock = irBlocks[i];
+
+            for (auto it = irBlock.instructions.begin(), end = irBlock.instructions.end();
+                it != end && it->type == ir_instruction::Phi;
+                ++it) {
+                assert(it->destination.has_value() && it->destination->type == ir_operand::Register);
+                const auto& phiDst = it->destination->value.reg;
+
+                for (auto& op : it->sources) {
+                    assert(op.type == ir_operand::PhiPair);
+                    const auto& predBlock = lifeBlocks[op.value.phiPair.block];
+                    auto&       phiArg    = op.value.phiPair.reg;
+                    if (predBlock.liveOut.count(phiArg) == 0 || phiArg == phiDst) continue;
+
+                    auto oldArg = phiArg;
+                    phiArg.ver  = 0; // TODO: Allocate temporary registers
+
+                    auto& irBlock = irBlocks[op.value.phiPair.block];
+                    assert(!irBlock.instructions.empty());
+                    auto it = irBlock.instructions.end() - 1;
+                    if (ir_instruction::is_terminating(it->type)) --it;
+                    irBlock.instructions.emplace(it,
+                        ir_instruction{ ir_instruction::Move,
+                            ir_operand::reg(phiArg.name, phiArg.ver),
+                            { ir_operand::reg(oldArg.name, oldArg.ver) } });
+                }
+            }
+        }
+    }
+
+    static void merge(std::vector<ir_basic_block>& irBlocks) {
+        disjoint_set dj;
+
+        for (const auto& block : irBlocks) {
+            for (const auto& instr : block.instructions) {
+                if (instr.type != ir_instruction::Phi) break;
+
+                assert(instr.destination.has_value() && instr.destination->type == ir_operand::Register);
+                const auto& phiDst = instr.destination->value.reg;
+                dj.find(phiDst);
+
+                for (const auto& op : instr.sources) {
+                    assert(op.type == ir_operand::PhiPair);
+                    const auto& predBlock = op.value.phiPair.block;
+                    const auto& phiArg    = op.value.phiPair.reg;
+                    dj.unite(phiDst, phiArg);
+                }
+            }
+        }
+
+        for (auto& block : irBlocks) {
+            auto it = block.instructions.begin();
+            while (it != block.instructions.end() && it->type == ir_instruction::Phi) {
+                it = block.instructions.erase(it);
+            }
+            for (; it != block.instructions.end(); ++it) {
+                for (auto& op : it->sources) {
+                    if (op.type != ir_operand::Register) continue;
+                    op.value.reg = dj.find(op.value.reg);
+                }
+
+                if (!it->destination.has_value() || it->destination->type != ir_operand::Register) continue;
+                it->destination->value.reg = dj.find(it->destination->value.reg);
+            }
+        }
+    }
+};
+
+} // namespace furc
+
+#endif // FURC_MIDDLE_REG_GEN_HPP

include/furc/middle/ssa.hpp

@@ -0,0 +1,101 @@
+#ifndef FURC_MIDDLE_SSA_HPP
+#define FURC_MIDDLE_SSA_HPP
+
+#include "furc/middle/ir.hpp"
+
+#include <cassert>
+#include <limits>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+
+namespace furc {
+
+class ssa {
+public:
+    struct cfg_block {
+        std::unordered_set<std::uint64_t> preds;
+        std::unordered_set<std::uint64_t> sucs;
+    };
+
+    struct ssa_block {
+        std::size_t order = 0;
+
+        std::uint64_t idom = -1;
+
+        std::unordered_set<std::uint64_t> children; // Children of the block in dominator tree
+
+        // Dominance Frontiers
+        std::unordered_set<std::uint64_t> df;
+    };
+
+    struct register_info {
+        std::unordered_set<std::uint64_t> sites; // Definition Sites
+    };
+public:
+    ssa(ir_function& func) {
+        registers.resize(func.regCount);
+        compute_cfg(func.blocks, cfgBlocks);
+        collect_registers(func.blocks, registers, globals);
+
+        std::vector<std::uint64_t> order;
+        compute_rpo(cfgBlocks, ssaBlocks, order);
+
+        build_dtree(cfgBlocks, ssaBlocks, order);
+        compute_dfrontiers(cfgBlocks, ssaBlocks);
+
+        ssaification(func.blocks, cfgBlocks, ssaBlocks, registers, globals);
+        rename(func.blocks, func.regCount, cfgBlocks, ssaBlocks, order);
+    }
+public:
+    static void compute_cfg(const std::vector<ir_basic_block>& irBlocks, std::vector<cfg_block>& cfgBlocks);
+
+    static void collect_registers(const std::vector<ir_basic_block>& irBlocks,
+        std::vector<register_info>&                                  registers,
+        std::unordered_set<std::uint64_t>&                           globals);
+
+    static void build_dtree(const std::vector<cfg_block>& cfgBlocks,
+        std::vector<ssa_block>&                           ssaBlocks,
+        const std::vector<std::size_t>&                   order);
+
+    static void compute_dfrontiers(const std::vector<cfg_block>& cfgBlocks, std::vector<ssa_block>& ssaBlocks);
+
+    static void compute_rpo(std::vector<cfg_block>& cfgBlocks,
+        std::vector<ssa_block>&                     ssaBlocks,
+        std::vector<std::size_t>&                   order);
+
+    static void ssaification(std::vector<ir_basic_block>& irBlocks,
+        const std::vector<cfg_block>&                     cfgBlocks,
+        const std::vector<ssa_block>&                     ssaBlocks,
+        const std::vector<register_info>&                 registers,
+        const std::unordered_set<std::uint64_t>&          globals);
+
+    static void rename(std::vector<ir_basic_block>& irBlocks,
+        std::size_t                                 regCount,
+        const std::vector<cfg_block>&               cfgBlocks,
+        std::vector<ssa_block>&                     ssaBlocks,
+        const std::vector<std::uint64_t>&           order);
+private:
+    static void rename_rec(std::vector<std::uint64_t>& counters,
+        std::vector<std::stack<std::uint64_t>>&        stacks,
+        std::vector<ir_basic_block>&                   irBlocks,
+        const std::vector<cfg_block>&                  cfgBlocks,
+        const std::vector<ssa_block>&                  ssaBlocks,
+        std::size_t                                    blockIdx);
+private:
+    static void rpo_dfs(std::unordered_set<std::size_t>& visited,
+        std::vector<std::size_t>&                        order,
+        std::size_t                                      block,
+        const std::vector<cfg_block>&                    blocks);
+
+    static std::size_t intersect(std::vector<ssa_block>& m_blocks, std::size_t b1, std::size_t b2);
+public:
+    std::vector<cfg_block>            cfgBlocks;
+    std::vector<ssa_block>            ssaBlocks;
+    std::vector<register_info>        registers;
+    std::unordered_set<std::uint64_t> globals;
+};
+
+} // namespace furc
+
+#endif // FURC_MIDDLE_SSA_HPP

include/furlang/result.hpp

@@ -2,7 +2,9 @@
 #define FURLANG_RESULT_HPP
 
 #include <exception>
+#include <optional>
 #include <ostream>
+#include <type_traits>
 #include <utility>
 
 namespace furlang {
@@ -43,6 +45,8 @@ public:
     const char* what() const noexcept override { return "bad result access"; }
 };
 
+struct error_tag {};
+
 /**
  * @brief Result.
  *
@@ -51,7 +55,7 @@ public:
  * @tparam R Value type.
  * @tparam E Error type.
  */
-template <typename R, typename E>
+template <typename E, typename R = void>
 class result {
 public:
     using value_type            = std::remove_reference_t<R>; /**< Value type. */
@@ -63,6 +67,10 @@ public:
     using error_reference       = error_type&;                /**< Error reference type. */
     using error_const_reference = const error_type&;          /**< Error const reference type. */
 public:
+    template <typename Other>
+    result(const result<E, Other>& error)
+      : result(error_tag{}, error.error()) {}
+
     /**
      * @brief Construct a new result.
      *
@@ -82,7 +90,7 @@ public:
      *
      * @param args Variadic arguments to construct the value with.
      */
-    template <typename... Args>
+    template <typename... Args, typename = std::enable_if_t<std::is_constructible_v<value_type, Args...>>>
     result(Args&&... args) {
         new (&m_value.result) value_type(std::forward<Args>(args)...);
     }
@@ -92,7 +100,7 @@ public:
      *
      * @param error Error to copy.
      */
-    explicit result(const error_type& error)
+    result(error_tag tag, const error_type& error)
       : m_error(true) {
         new (&m_value.error) error_type(error);
     }
@@ -102,7 +110,7 @@ public:
      *
      * @param error Error to move.
      */
-    explicit result(error_type&& error)
+    result(error_tag tag, error_type&& error)
       : m_error(true) {
         new (&m_value.error) error_type(std::move(error));
     }
@@ -166,6 +174,16 @@ public:
         }
         return *this;
     }
+public:
+    template <typename ResultFwd, typename = std::enable_if_t<std::is_constructible_v<R, ResultFwd>>>
+    static result ok(ResultFwd&& value) {
+        return { std::forward<ResultFwd>(value) };
+    }
+
+    template <typename ErrorFwd, typename = std::enable_if_t<std::is_constructible_v<E, ErrorFwd>>>
+    static result error(ErrorFwd&& value) {
+        return { error_tag{}, std::forward<ErrorFwd>(value) };
+    }
 public:
     /**
      * @brief Checks if this result contains a value.
@@ -364,6 +382,34 @@ private:
     bool m_error = false;
 };
 
+template <typename E>
+class result<E, void> {
+public:
+    using value_type      = std::remove_reference_t<E>;
+    using reference       = value_type&;
+    using const_reference = const value_type&;
+public:
+    result() = default;
+
+    result(const value_type& value)
+      : m_error(true), m_value(value) {}
+
+    result(value_type&& value)
+      : m_error(true), m_value(std::move(value)) {}
+
+    template <typename... Args, typename = std::enable_if_t<std::is_constructible_v<value_type, Args...>>>
+    result(Args&&... args)
+      : m_error(true), m_value(std::forward<Args>(args)...) {}
+public:
+    bool has_value() const { return !m_error; }
+    bool has_error() const { return m_error; }
+
+    const value_type& error() const { return *m_value; }
+private:
+    std::optional<value_type> m_value;
+    bool                      m_error = false;
+};
+
 } // namespace furlang
 
-#endif // FURLANG_RESULT_HPP
+#endif // FURLANG_RESULT_HPP

include/furlang/serialization/codec.hpp

@@ -0,0 +1,58 @@
+#ifndef FURLANG_SERIALIZATION_CODEC_HPP
+#define FURLANG_SERIALIZATION_CODEC_HPP
+
+#include "furlang/result.hpp"
+#include "furlang/serialization/io.hpp"
+
+#include <type_traits>
+#include <utility>
+
+namespace furlang {
+namespace serialization {
+
+template <typename Codec, typename T>
+using codec_encode_result_t = decltype(std::declval<Codec>().encode(std::declval<writer&>(), std::declval<const T&>()));
+
+template <typename Codec, typename T>
+using codec_decode_result_t = decltype(std::declval<Codec>().decode(std::declval<reader&>()));
+
+template <typename Codec, typename T, typename = void>
+struct is_codec : std::false_type {};
+
+template <typename Codec, typename T>
+struct is_codec<Codec, T, std::void_t<codec_encode_result_t<Codec, T>, codec_decode_result_t<Codec, T>>>
+  : std::true_type {};
+
+template <typename Codec, typename T>
+constexpr bool is_codec_v = is_codec<Codec, T>::value;
+
+template <typename Codec, typename T, typename = std::enable_if_t<is_codec_v<Codec, T>>>
+result<error> encode(Codec& codec, writer& writer, const T& value) {
+    return codec.encode(writer, value);
+}
+
+template <typename Codec, typename T, typename = std::enable_if_t<is_codec_v<Codec, T>>>
+result<error, T> decode(Codec& codec, reader& reader) {
+    return codec.decode(reader);
+}
+
+template <typename T, typename = void>
+class codec;
+
+template <typename T>
+struct codec<T, std::enable_if_t<std::is_integral_v<T>>> {
+    result<error>    encode(writer& writer, const T& value) { return writer.write_int(value); }
+    result<error, T> decode(reader& reader) { return reader.read_int(T{}); }
+};
+
+template <>
+struct codec<std::string> {
+    result<error> encode(writer& writer, const std::string& value) { return writer.write_string(value); }
+
+    result<error, std::string> decode(reader& reader) { return reader.read_string(); }
+};
+
+} // namespace serialization
+} // namespace furlang
+
+#endif // FURLANG_SERIALIZATION_CODEC_HPP

include/furlang/serialization/error.hpp

@@ -0,0 +1,33 @@
+#ifndef FURLANG_SERIALIZATION_ERROR_HPP
+#define FURLANG_SERIALIZATION_ERROR_HPP
+
+#include <cstddef>
+#include <string>
+
+namespace furlang {
+namespace serialization {
+
+enum class error_code {
+    EndOfFile,
+    InvalidData,
+    InvalidTag,
+    InvalidVersion,
+    IntegerOverflow,
+    SizeLimit,
+    DuplicateId,
+    UnknownId,
+    TypeMismatch,
+    Unsupported,
+};
+
+struct error {
+    error_code  code;
+    std::string message;
+
+    std::size_t offset = 0;
+};
+
+} // namespace serialization
+} // namespace furlang
+
+#endif // FURLANG_SERIALIZATION_ERROR_HPP

include/furlang/serialization/io.hpp

@@ -0,0 +1,190 @@
+#ifndef FURLANG_SERIALIZATION_IO_HPP
+#define FURLANG_SERIALIZATION_IO_HPP
+
+#include "furlang/result.hpp"
+#include "furlang/serialization/error.hpp"
+
+#include <cstdint>
+#include <string>
+#include <string_view>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+namespace furlang {
+namespace serialization {
+
+class writer {
+public:
+    writer()          = default;
+    virtual ~writer() = default;
+
+    writer(writer&&) noexcept            = default;
+    writer& operator=(writer&&) noexcept = default;
+    writer(const writer&)                = default;
+    writer& operator=(const writer&)     = default;
+public:
+    virtual result<error> write_s8(std::int8_t value)    = 0;
+    virtual result<error> write_u8(std::uint8_t value)   = 0;
+    virtual result<error> write_s16(std::int16_t value)  = 0;
+    virtual result<error> write_u16(std::uint16_t value) = 0;
+    virtual result<error> write_s32(std::int32_t value)  = 0;
+    virtual result<error> write_u32(std::uint32_t value) = 0;
+    virtual result<error> write_s64(std::int64_t value)  = 0;
+    virtual result<error> write_u64(std::uint64_t value) = 0;
+
+    result<error> write_int(std::int8_t value) { return write_s8(value); }
+    result<error> write_int(std::uint8_t value) { return write_u8(value); }
+    result<error> write_int(std::int16_t value) { return write_s16(value); }
+    result<error> write_int(std::uint16_t value) { return write_u16(value); }
+    result<error> write_int(std::int32_t value) { return write_s32(value); }
+    result<error> write_int(std::uint32_t value) { return write_u32(value); }
+    result<error> write_int(std::int64_t value) { return write_s64(value); }
+    result<error> write_int(std::uint64_t value) { return write_u64(value); }
+
+    virtual result<error> write_string(const char* string)        = 0;
+    virtual result<error> write_string(std::string_view string)   = 0;
+    virtual result<error> write_string(const std::string& string) = 0;
+};
+
+class reader {
+public:
+    reader()          = default;
+    virtual ~reader() = default;
+
+    reader(reader&&) noexcept            = default;
+    reader& operator=(reader&&) noexcept = default;
+    reader(const reader&)                = default;
+    reader& operator=(const reader&)     = default;
+public:
+    virtual result<error, std::int8_t>   read_s8()  = 0;
+    virtual result<error, std::uint8_t>  read_u8()  = 0;
+    virtual result<error, std::int16_t>  read_s16() = 0;
+    virtual result<error, std::uint16_t> read_u16() = 0;
+    virtual result<error, std::int32_t>  read_s32() = 0;
+    virtual result<error, std::uint32_t> read_u32() = 0;
+    virtual result<error, std::int64_t>  read_s64() = 0;
+    virtual result<error, std::uint64_t> read_u64() = 0;
+
+    result<error, std::int8_t>   read_int(std::int8_t) { return read_s8(); }
+    result<error, std::uint8_t>  read_int(std::uint8_t) { return read_u8(); }
+    result<error, std::int16_t>  read_int(std::int16_t) { return read_s16(); }
+    result<error, std::uint16_t> read_int(std::uint16_t) { return read_u16(); }
+    result<error, std::int32_t>  read_int(std::int32_t) { return read_s32(); }
+    result<error, std::uint32_t> read_int(std::uint32_t) { return read_u32(); }
+    result<error, std::int64_t>  read_int(std::int64_t) { return read_s64(); }
+    result<error, std::uint64_t> read_int(std::uint64_t) { return read_u64(); }
+
+    virtual result<error, std::string> read_string() = 0;
+
+    virtual std::size_t offset() const = 0;
+};
+
+enum class endianness {
+    Little = 0,
+    Big    = 1,
+};
+
+class byte_writer : public writer {
+public:
+    byte_writer(endianness endianness = endianness::Big)
+      : m_endianness(endianness) {}
+public:
+    result<error> write_s8(std::int8_t value) override;
+    result<error> write_u8(std::uint8_t value) override;
+    result<error> write_s16(std::int16_t value) override;
+    result<error> write_u16(std::uint16_t value) override;
+    result<error> write_s32(std::int32_t value) override;
+    result<error> write_u32(std::uint32_t value) override;
+    result<error> write_s64(std::int64_t value) override;
+    result<error> write_u64(std::uint64_t value) override;
+
+    result<error> write_string(const char* string) override;
+    result<error> write_string(std::string_view string) override;
+    result<error> write_string(const std::string& string) override;
+private:
+    template <typename T, typename = std::enable_if_t<std::is_integral_v<T>>>
+    result<error> write_integral_le(T value) {
+        return write_integral_le(value, std::make_index_sequence<sizeof(T)>{});
+    }
+
+    template <typename T, typename = std::enable_if_t<std::is_integral_v<T>>, std::size_t... I>
+    result<error> write_integral_le(T value, std::index_sequence<I...>) {
+        auto usig = static_cast<std::make_unsigned_t<T>>(value);
+        (m_bytes.push_back(usig >> (I * 8)), ...);
+        return {};
+    }
+private:
+    template <typename T, typename = std::enable_if_t<std::is_integral_v<T>>>
+    void write_integral_be(T value) {
+        write_integral_be(value, std::make_index_sequence<sizeof(T)>{});
+    }
+
+    template <typename T, typename = std::enable_if_t<std::is_integral_v<T>>, std::size_t... I>
+    void write_integral_be(T value, std::index_sequence<I...>) {
+        auto usig = static_cast<std::make_unsigned_t<T>>(value);
+        (m_bytes.push_back(usig >> ((sizeof(T) - 1 - I) * 8)), ...);
+    }
+private:
+    endianness                m_endianness;
+    std::vector<std::uint8_t> m_bytes;
+};
+
+class byte_reader : public reader {
+public:
+    byte_reader(const std::uint8_t* bytes, std::size_t length, endianness endianness = endianness::Big)
+      : m_endianness(endianness), m_bytes(bytes), m_length(length) {}
+public:
+    result<error, std::int8_t>   read_s8() override;
+    result<error, std::uint8_t>  read_u8() override;
+    result<error, std::int16_t>  read_s16() override;
+    result<error, std::uint16_t> read_u16() override;
+    result<error, std::int32_t>  read_s32() override;
+    result<error, std::uint32_t> read_u32() override;
+    result<error, std::int64_t>  read_s64() override;
+    result<error, std::uint64_t> read_u64() override;
+
+    result<error, std::string> read_string() override;
+
+    std::size_t offset() const override;
+private:
+    result<error, std::uint8_t> read_byte() {
+        if (m_offset >= m_length)
+            return result<error, std::uint8_t>::error(error{ error_code::EndOfFile, "", m_offset });
+        return { m_bytes[m_offset++] };
+    }
+private:
+    template <typename T, typename = std::enable_if_t<std::is_integral_v<T>>>
+    result<error, T> read_integral_le() {
+        using U = std::make_unsigned_t<T>;
+        U usig  = 0;
+        for (std::size_t i = 0; i < sizeof(T); ++i) {
+            auto res = read_byte();
+            if (res.has_error()) return res;
+            usig |= static_cast<U>(res.value()) << (i * 8);
+        }
+        return { static_cast<T>(usig) };
+    }
+private:
+    template <typename T, typename = std::enable_if_t<std::is_integral_v<T>>>
+    result<error, T> read_integral_be() {
+        using U = std::make_unsigned_t<T>;
+        U usig  = 0;
+        for (std::size_t i = 0; i < sizeof(T); ++i) {
+            auto res = read_byte();
+            if (res.has_error()) return res;
+            usig |= static_cast<U>(res.value()) << ((sizeof(T) - 1 - i) * 8);
+        }
+        return { static_cast<T>(usig) };
+    }
+private:
+    endianness          m_endianness;
+    const std::uint8_t* m_bytes;
+    std::size_t         m_length;
+    std::size_t         m_offset = 0;
+};
+
+} // namespace serialization
+} // namespace furlang
+
+#endif // FURLANG_SERIALIZATION_IO_HPP

include/furvm/constant.hpp

@@ -0,0 +1,31 @@
+#ifndef FURVM_CONSTANT_HPP
+#define FURVM_CONSTANT_HPP
+
+#include "furvm/fwd.hpp"
+
+#include <cstdint>
+#include <string_view>
+
+namespace furvm {
+
+// TODO: Array constants
+struct constant {
+    enum type_e {
+        S32 = 0,
+        U32,
+        S64,
+        U64,
+        String,
+    } type = S32;
+    union {
+        std::int32_t     s32;
+        std::uint32_t    u32;
+        std::int64_t     s64;
+        std::uint64_t    u64;
+        std::string_view string;
+    };
+};
+
+} // namespace furvm
+
+#endif // FURVM_CONSTANT_HPP

include/furvm/executor.hpp

@@ -3,7 +3,8 @@
 
 #include "furvm/fwd.hpp"
 #include "furvm/module.hpp" // IWYU pragma: keep
-#include "furvm/thing.hpp"  // IWYU pragma: keep
+#include "furvm/stack.hpp"
+#include "furvm/thing.hpp" // IWYU pragma: keep
 
 #include <functional>
 #include <stack>
@@ -39,6 +40,8 @@ public:
     static constexpr executor_flags STATE_FLAGS = executor_flags::JustHit;
 
     using new_frame_callback = std::function<void(executor&)>;
+
+    using stack_thing = thing<stack_allocator>;
 public:
     /**
      * @brief Executor frame.
@@ -50,8 +53,8 @@ public:
         std::size_t position;  /**< Cursor to a current instruction in the bytecode. */
         std::size_t stackBase; /**< Snapshot of the stack size before this frame. */
 
-        thing_type*          returnType; /**< Return type. */
+        thing_type*              returnType; /**< Return type. */
-        std::vector<thing<>> variables;  /**< Frame variables. */
+        std::vector<stack_thing> variables;  /**< Frame variables. */
     };
 public:
     ~executor() = default;
@@ -131,27 +134,27 @@ public:
      * @param thing Thing.
      * @return The pushed handle.
      */
-    thing<>& push_thing(thing<>&& thing);
+    stack_thing& push_thing(stack_thing&& thing);
 
-    thing<>& push_thing(const thing<>& thing);
+    stack_thing& push_thing(const stack_thing& thing);
 
     /**
      * @brief Pops a thing from the stack.
      *
      * @return A handle to the popped thing.
      */
-    thing<> pop_thing();
+    stack_thing pop_thing();
 
     /**
      * @brief Returns the top thing on the stack.
      *
      * @return A handle to the top thing.
      */
-    thing<>& top_thing();
+    stack_thing& top_thing();
 
-    const thing<>& top_thing() const;
+    const stack_thing& top_thing() const;
 
-    const std::vector<thing<>>& stack() const { return m_stack; }
+    const std::vector<stack_thing>& stack() const { return m_stack; }
 public:
     /**
      * @brief Stores a thing in a frame variable.
@@ -159,7 +162,7 @@ public:
      * @param variable Id of the variable in which the handle will be put.
      * @param thing Thing handle.
      */
-    void store_thing(variable_t variable, const thing<>& thing);
+    void store_thing(variable_t variable, const stack_thing& thing);
 
     /**
      * @brief Stores a thing in a frame variable.
@@ -167,7 +170,7 @@ public:
      * @param variable Id of the variable in which the handle will be put.
      * @param thing Thing handle.
      */
-    void store_thing(variable_t variable, thing<>&& thing);
+    void store_thing(variable_t variable, stack_thing&& thing);
 
     /**
      * @brief Returns a thing stored in a variable.
@@ -175,9 +178,9 @@ public:
      * @param variable Id of the variable from which the handle will be fetched.
      * @return A handle stored in the variable.
      */
-    thing<>& load_thing(variable_t variable);
+    stack_thing& load_thing(variable_t variable);
 
-    const thing<>& load_thing(variable_t variable) const;
+    const stack_thing& load_thing(variable_t variable) const;
 public:
     /**
      * @brief Executes next instruction.
@@ -190,11 +193,12 @@ private:
 private:
     static bool compare_thing_types(const thing_type& lhs, const thing_type& rhs);
 private:
-    executor_flags m_flags = executor_flags::Done;
+    executor_flags          m_flags = executor_flags::Done;
-    context*       m_context;
+    context*                m_context;
+    furvm::stack<std::byte> m_stackStorage;
 
-    std::stack<frame>    m_frames;
+    std::stack<frame>        m_frames;
-    std::vector<thing<>> m_stack;
+    std::vector<stack_thing> m_stack;
 
     new_frame_callback m_newFrameCb = nullptr;
 };

include/furvm/function.hpp

@@ -1,7 +1,6 @@
 #ifndef FURVM_FUNCTION_HPP
 #define FURVM_FUNCTION_HPP
 
-#include "furlang/utility/hash.hpp"
 #include "furvm/fwd.hpp"
 #include "furvm/handle.hpp" // IWYU pragma: keep
 

include/furvm/instruction.hpp

@@ -56,6 +56,7 @@ struct instruction {
         PushU32,
         PushConstant,
         Array,
+        Slice,
         Get,
         Set,
         Drop,

include/furvm/module.hpp

@@ -3,6 +3,7 @@
 
 #include "furlang/utility/hash.hpp"
 #include "furlang/view.hpp"
+#include "furvm/constant.hpp"
 #include "furvm/function.hpp"
 #include "furvm/fwd.hpp"
 #include "furvm/handle.hpp"
@@ -10,8 +11,6 @@
 
 #include <functional>
 #include <istream>
-#include <limits>
-#include <optional>
 #include <ostream>
 #include <stdexcept>
 #include <string>
@@ -28,6 +27,10 @@ struct mod_type {
         std::size_t size;
     };
 
+    struct slice_value {
+        mod_type_id typeId;
+    };
+
     struct import_value {
         mod_id      modId;
         mod_type_id typeId;
@@ -45,6 +48,7 @@ struct mod_type {
         Ptr,
         Ref,
         Array,
+        Slice,
 
         Import,
         Count,
@@ -53,6 +57,7 @@ struct mod_type {
         std::nullptr_t null = nullptr;
         mod_type_id    typeRef;
         array_value    array;
+        slice_value    slice;
         import_value   imprt;
 
         value() = default;
@@ -97,6 +102,7 @@ struct mod_type {
     ~mod_type() {
         switch (type) {
         case Array: value.array.~array_value(); break;
+        case Slice: value.slice.~slice_value(); break;
         case Import: value.imprt.~import_value(); break;
         default: break;
         }
@@ -106,6 +112,7 @@ struct mod_type {
       : type(other.type) {
         switch (type) {
         case Array: new (&value.array) array_value(other.value.array); break;
+        case Slice: new (&value.slice) slice_value(other.value.slice); break;
         case Import: new (&value.imprt) import_value(std::move(other.value.imprt)); break;
         default: break;
         }
@@ -117,6 +124,7 @@ struct mod_type {
         type = other.type;
         switch (type) {
         case Array: new (&value.array) array_value(other.value.array); break;
+        case Slice: new (&value.slice) slice_value(other.value.slice); break;
         case Import: new (&value.imprt) import_value(std::move(other.value.imprt)); break;
         default: break;
         }
@@ -128,6 +136,7 @@ struct mod_type {
       : type(other.type) {
         switch (type) {
         case Array: new (&value.array) array_value(other.value.array); break;
+        case Slice: new (&value.slice) slice_value(other.value.slice); break;
         case Import: new (&value.imprt) import_value(other.value.imprt); break;
         default: break;
         }
@@ -138,6 +147,7 @@ struct mod_type {
         type = other.type;
         switch (type) {
         case Array: new (&value.array) array_value(other.value.array); break;
+        case Slice: new (&value.slice) slice_value(other.value.slice); break;
         case Import: new (&value.imprt) import_value(other.value.imprt); break;
         default: break;
         }
@@ -384,6 +394,13 @@ public:
         if (var >= m_globalVariables.size()) throw std::runtime_error("invalid slot");
         return m_globalVariables[var];
     }
+public:
+    template <typename... Args, typename = std::enable_if_t<std::is_constructible_v<constant, Args...>>>
+    void emplace_constant(Args&&... args) {
+        m_constants.emplace_back(std::forward<Args>(args)...);
+    }
+
+    const constant& constant_at(constant_index index) const { return m_constants.at(index); }
 public:
     template <typename Fwd, typename = std::enable_if_t<std::is_constructible_v<breakpoint, Fwd>>>
     void set_breakpoint(bytecode_pos pos, Fwd&& breakpoint) {
@@ -423,6 +440,8 @@ private:
 
     std::vector<thing<>> m_globalVariables;
 
+    std::vector<constant> m_constants;
+
     std::unordered_map<std::string, native_function> m_nativeFunctions;
 
     std::unordered_map<bytecode_pos, breakpoint> m_breakpoints;

include/furvm/stack.hpp

@@ -0,0 +1,56 @@
+#ifndef FURVM_STACK_HPP
+#define FURVM_STACK_HPP
+
+#include <cstddef>
+#include <new>
+#include <stack>
+
+namespace furvm {
+
+template <typename T>
+struct stack {
+    stack(std::size_t capacity = (1024ULL * 1024ULL) / sizeof(T))
+      : begin(new T[capacity]()), cursor(begin), capacity(capacity) {}
+
+    T*             begin;
+    T*             cursor;
+    std::size_t    capacity;
+    std::stack<T*> frames;
+
+    void push_frame() { frames.push(cursor); }
+
+    void pop_frame() {
+        cursor = frames.top();
+        frames.pop();
+    }
+};
+
+template <typename T>
+class stack_allocator {
+public:
+    stack_allocator() = default;
+
+    stack_allocator(stack<T>& stack)
+      : m_ref(&stack) {}
+
+    template <typename U>
+    constexpr stack_allocator(const stack_allocator<U>& other) noexcept
+      : m_ref(other.m_ref) {}
+public:
+    T* allocate(std::size_t n) {
+        if (m_ref == nullptr) throw std::bad_alloc();
+        if (m_ref->capacity - (m_ref->cursor - m_ref->begin) < n) throw std::bad_alloc();
+
+        T* ptr         = m_ref->cursor;
+        m_ref->cursor += n;
+        return ptr;
+    }
+
+    void deallocate(T* ptr, std::size_t n) {}
+private:
+    stack<T>* m_ref = nullptr;
+};
+
+} // namespace furvm
+
+#endif // FURVM_STACK_HPP

include/furvm/thing.hpp

@@ -5,13 +5,14 @@
 #include "furlang/utility/hash.hpp"
 #include "furvm/exceptions.hpp"
 #include "furvm/fwd.hpp"
+#include "furvm/types.hpp"
 
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
 #include <cstring>
 #include <functional>
-#include <limits>
+#include <iterator>
 #include <new>
 #include <stdexcept>
 #include <type_traits>
@@ -20,115 +21,6 @@
 
 namespace furvm {
 
-struct thing_type {
-    using s8  = std::int8_t;
-    using s16 = std::int16_t;
-    using s32 = std::int32_t;
-    using s64 = std::int64_t;
-    using u8  = std::uint8_t;
-    using u16 = std::uint16_t;
-    using u32 = std::uint32_t;
-    using u64 = std::uint64_t;
-
-    struct array_value {
-        thing_type* type;
-        std::size_t size;
-    };
-
-    enum type { // NOLINT
-        S8 = 0,
-        S16,
-        S32,
-        S64,
-        U8,
-        U16,
-        U32,
-        U64,
-        Ptr,
-        Ref,
-        Array,
-
-        Count,
-    } type = Count;
-    union value {
-        std::nullptr_t null = nullptr;
-        thing_type*    typeRef;
-        array_value    array;
-
-        value() = default;
-
-        value(thing_type* type)
-          : typeRef(type) {}
-
-        value(thing_type* type, std::size_t size)
-          : array({}) {
-            array.type = type;
-            array.size = size;
-        }
-    } value;
-
-    static constexpr thing_type_id INVALID_ID = std::numeric_limits<thing_type_id>::max();
-
-    thing_type_id id = INVALID_ID;
-
-    bool operator==(const thing_type& other) const {
-        if (type != other.type) return false;
-        switch (type) {
-        case S8:
-        case S16:
-        case S32:
-        case S64:
-        case U8:
-        case U16:
-        case U32:
-        case U64: return true;
-        case Ptr:
-        case Ref: return *value.typeRef == *other.value.typeRef;
-        case Array: return *value.array.type == *other.value.array.type && value.array.size == other.value.array.size;
-        case Count: break;
-        }
-        return false;
-    }
-
-    bool operator!=(const thing_type& other) const { return !this->operator==(other); }
-
-    static bool is_primitive(enum type type) {
-        switch (type) {
-        case S8:
-        case S16:
-        case S32:
-        case S64:
-        case U8:
-        case U16:
-        case U32:
-        case U64: return true;
-        case Ptr:
-        case Ref:
-        case Array: return false;
-        case Count: break;
-        }
-        throw std::runtime_error("unreachable");
-    }
-
-    static std::size_t primitive_size(enum type type) {
-        switch (type) {
-        case thing_type::S8: return sizeof(s8);
-        case thing_type::S16: return sizeof(s16);
-        case thing_type::S32: return sizeof(s32);
-        case thing_type::S64: return sizeof(s64);
-        case thing_type::U8: return sizeof(u8);
-        case thing_type::U16: return sizeof(u16);
-        case thing_type::U32: return sizeof(u32);
-        case thing_type::U64: return sizeof(u64);
-        case Ptr:
-        case Ref:
-        case Array: return 0;
-        case Count: break;
-        }
-        throw std::runtime_error("unreachable");
-    }
-};
-
 namespace detail {
 
 struct thing_type_hash {
@@ -142,7 +34,8 @@ struct thing_type_hash {
         case thing_type::U8:
         case thing_type::U16:
         case thing_type::U32:
-        case thing_type::U64: return seed;
+        case thing_type::U64:
+        case thing_type::String: return seed;
         case thing_type::Ptr:
         case thing_type::Ref: return furlang::utility::hash_combine(seed, thing_type_hash{}(*type.value.typeRef));
         case thing_type::Array:
@@ -150,6 +43,7 @@ struct thing_type_hash {
             seed = furlang::utility::hash_combine(seed,
                 std::hash<decltype(type.value.array.size)>{}(type.value.array.size));
             return seed;
+        case thing_type::Slice: return furlang::utility::hash_combine(seed, thing_type_hash{}(*type.value.slice.type));
         case thing_type::Count: break;
         }
         throw std::runtime_error("unreachable");
@@ -194,19 +88,139 @@ private:
 template <template <typename> typename Allocator>
 class thing final {
     friend class executor;
+
+    template <template <typename> class Other>
+    friend class thing;
 public:
     using allocator_type = Allocator<std::byte>; /**< Allocator type. */
 public:
+    struct string {
+        std::size_t size;
+        u8*         data;
+
+        static bool matches(const thing_type& type) { return type.type == thing_type::String; }
+    };
+
     struct dynamic_array {
         std::size_t size;
         std::byte*  data;
+
+        static bool matches(const thing_type& type) {
+            return type.type == thing_type::Array && type.value.array.size == 0;
+        }
+    };
+
+    struct slice {
+        std::size_t length;
+        std::byte*  data;
+
+        static bool matches(const thing_type& type) { return type.type == thing_type::Slice; }
     };
 
     struct header {
         thing_type type;
     };
+private:
+    template <bool Const>
+    class generic_iterator {
+        using owner_type = std::conditional_t<Const, const thing, thing>;
+        using data_type  = std::byte;
+    public:
+        using difference_type   = std::ptrdiff_t;
+        using value_type        = thing;
+        using pointer           = std::conditional_t<Const, const value_type*, value_type*>;
+        using reference         = std::conditional_t<Const, const value_type&, value_type&>;
+        using iterator_category = std::random_access_iterator_tag;
+    public:
+        generic_iterator() = default;
+
+        generic_iterator(owner_type* owner, data_type* ptr)
+          : m_owner(owner), m_ptr(ptr) {
+            fill();
+        }
+    public:
+        reference operator*() { return m_thing; }
+
+        value_type operator*() const {
+            thing thing = { m_thing.type() };
+            thing.assign(m_thing);
+            return thing;
+        }
+
+        reference operator[](difference_type n) { return *(*this + n); }
+
+        pointer operator->() { return &m_thing; }
+
+        generic_iterator& operator+=(difference_type n) {
+            m_ptr += n * step_size();
+            fill();
+            return *this;
+        }
+
+        generic_iterator& operator-=(difference_type n) {
+            m_ptr -= n * step_size();
+            fill();
+            return *this;
+        }
+
+        generic_iterator operator+(difference_type n) const { return { m_owner, m_ptr + (n * step_size()) }; }
+
+        friend generic_iterator operator+(difference_type n, const generic_iterator& it) {
+            return { it.m_owner, it.m_ptr + (n * it.step_size()) };
+        }
+
+        generic_iterator operator-(difference_type n) const { return { m_owner, m_ptr - (n * step_size()) }; }
+
+        difference_type operator-(const generic_iterator& other) const { return (m_ptr - other.m_ptr) / step_size(); }
+
+        generic_iterator& operator++() {
+            m_ptr += step_size();
+            fill();
+            return *this;
+        }
+
+        generic_iterator operator++(int) { return { m_owner, m_ptr + step_size() }; }
+
+        generic_iterator& operator--() {
+            m_ptr -= step_size();
+            fill();
+            return *this;
+        }
+
+        generic_iterator operator--(int) { return { m_owner, m_ptr - step_size() }; }
+
+        bool operator==(const generic_iterator& other) const {
+            return m_owner == other.m_owner && m_ptr == other.m_ptr;
+        }
+
+        bool operator!=(const generic_iterator& other) const {
+            return m_owner != other.m_owner || m_ptr != other.m_ptr;
+        }
+
+        bool operator<(const generic_iterator& other) const { return other.m_ptr < m_ptr; }
+        bool operator>(const generic_iterator& other) const { return other.m_ptr > m_ptr; }
+        bool operator<=(const generic_iterator& other) const { return other.m_ptr <= m_ptr; }
+        bool operator>=(const generic_iterator& other) const { return other.m_ptr >= m_ptr; }
+    private:
+        difference_type step_size() const { return thing::compute_size_na(m_owner->inner_type()); }
+
+        void fill() {
+            m_thing.m_reference = true;
+            m_thing.m_data      = m_ptr;
+            m_thing.m_type      = &m_owner->inner_type();
+            m_thing.m_size      = compute_size_na(m_owner->inner_type());
+        }
+    private:
+        owner_type* m_owner = nullptr;
+        data_type*  m_ptr   = nullptr;
+        thing       m_thing;
+    };
+
+    using iterator       = generic_iterator<false>;
+    using const_iterator = generic_iterator<true>;
 public:
-    thing() {}
+    thing(const allocator_type& allocator = {})
+      : m_allocator(allocator) {}
 
     /**
      * @brief Constructs a thing.
@@ -230,15 +244,15 @@ public:
      *
      * TODO: Reword the note above.
      */
-    static thing make_reference(const thing& owner) {
+    template <template <typename> class Other = Allocator>
-        thing ref;
+    static thing make_reference(const thing<Other>& owner, const allocator_type& allocator = {}) {
+        thing ref       = { allocator };
         ref.m_reference = true;
         ref.m_data      = owner.m_data;
         ref.m_type      = owner.m_type;
         ref.m_size      = owner.m_size;
         return ref;
     }
-
     /**
      * @brief Destructs a thing.
      */
@@ -247,7 +261,16 @@ public:
     /**
      * @brief Move constructor.
      */
-    thing(thing&& other) noexcept { *this = std::move(other); }
+    thing(thing&& other) noexcept
+      : m_reference(other.m_reference),
+        m_type(other.m_type),
+        m_size(other.m_size),
+        m_data(other.m_data),
+        m_allocator(other.m_allocator) {
+        other.m_type = nullptr;
+        other.m_data = nullptr;
+        other.m_size = 0;
+    }
 
     /**
      * @brief Move constructor.
@@ -266,7 +289,16 @@ public:
         return *this;
     }
 
-    thing(const thing& other) { *this = other; }
+    thing(const thing& other)
+      : m_reference(other.m_reference), m_size(other.m_size), m_allocator(other.m_allocator) {
+        if (m_reference) {
+            m_type = other.m_type;
+            m_data = other.m_data;
+            return;
+        }
+        allocate(other.type());
+        other.copy(*this);
+    }
 
     thing& operator=(const thing& other) {
         if (this == &other) return *this;
@@ -275,7 +307,38 @@ public:
 
         m_reference = other.m_reference;
         m_size      = other.m_size;
-        m_allocator = other.m_allocator;
+
+        if (m_reference) {
+            m_type = other.m_type;
+            m_data = other.m_data;
+            return *this;
+        }
+        allocate(other.type());
+        other.copy(*this);
+
+        return *this;
+    }
+
+    template <template <typename> class Other>
+    thing(const thing<Other>& other)
+      : m_reference(other.m_reference), m_size(other.m_size) {
+        if (m_reference) {
+            m_type = other.m_type;
+            m_data = other.m_data;
+            return;
+        }
+        allocate(other.type());
+        other.copy(*this);
+    }
+
+    template <template <typename> class Other>
+    thing& operator=(const thing<Other>& other) {
+        if (this == &other) return *this;
+
+        free();
+
+        m_reference = other.m_reference;
+        m_size      = other.m_size;
 
         if (m_reference) {
             m_type = other.m_type;
@@ -299,7 +362,8 @@ public:
         return res;
     }
 private:
-    void copy(thing<>& dst) const {
+    template <template <typename> class Other>
+    void copy(thing<Other>& dst) const {
         switch (m_type->type) {
         case thing_type::S8:
         case thing_type::S16:
@@ -309,7 +373,8 @@ private:
         case thing_type::U16:
         case thing_type::U32:
         case thing_type::U64:
-        case thing_type::Ptr: std::memcpy(dst.m_data, m_data, m_size); return;
+        case thing_type::Ptr:
+        case thing_type::Slice: std::memcpy(dst.m_data, m_data, m_size); return;
         case thing_type::Array: copy_list(*m_type, dst.m_data, m_data); return;
         case thing_type::Ref: // TODO: Implement arrays of references (I think they're possible).
         case thing_type::Count: break;
@@ -360,7 +425,7 @@ public:
      */
     template <typename T>
     T& get() {
-        if (compute_size_na(*m_type) != sizeof(T)) throw bad_thing_access();
+        if (!detail::thing_traits<T>{}(*m_type)) throw bad_thing_access();
         return *std::launder(reinterpret_cast<T*>(m_data));
     }
 
@@ -371,9 +436,15 @@ public:
      */
     template <typename T>
     const T& get() const {
-        if (compute_size_na(*m_type) != sizeof(T)) throw bad_thing_access();
+        if (!detail::thing_traits<T>{}(*m_type)) throw bad_thing_access();
         return *std::launder(reinterpret_cast<const T*>(m_data));
     }
+
+    template <typename T>
+    void set(T&& newValue) {
+        if (!detail::thing_traits<T>{}(*m_type)) throw bad_thing_access();
+        *std::launder(reinterpret_cast<T*>(m_data)) = std::forward<T>(newValue);
+    }
 public:
     /**
      * @brief Returns a sum of two things.
@@ -468,60 +539,122 @@ public:
      *
      * @return The integer value.
      */
-    thing_type::s64 integer() const {
+    s64 integer() const {
         switch (type().type) {
-        case thing_type::S8: return get<thing_type::s8>();
+        case thing_type::S8: return get<s8>();
-        case thing_type::S16: return get<thing_type::s16>();
+        case thing_type::S16: return get<s16>();
-        case thing_type::S32: return get<thing_type::s32>();
+        case thing_type::S32: return get<s32>();
-        case thing_type::S64: return get<thing_type::s64>();
+        case thing_type::S64: return get<s64>();
-        case thing_type::U8: return get<thing_type::u8>();
+        case thing_type::U8: return get<u8>();
-        case thing_type::U16: return get<thing_type::u16>();
+        case thing_type::U16: return get<u16>();
-        case thing_type::U32: return get<thing_type::u32>();
+        case thing_type::U32: return get<u32>();
-        case thing_type::U64: return get<thing_type::u64>();
+        case thing_type::U64: return get<u64>();
         default: throw std::runtime_error("unreachable");
         }
     }
 
-    void resize(thing_type::u64 newSize) {
+    void resize(u64 newSize) {
-        if (!is(thing_type::Array)) throw bad_thing_access();
+        switch (type().type) {
-        if (type().value.array.size > 0) throw std::runtime_error("cannot resize a static array");
+        case thing_type::Array: {
+            if (type().value.array.size > 0) throw std::runtime_error("cannot resize a static array");
 
-        auto& array = get<dynamic_array>();
+            auto& array = get<dynamic_array>();
-        if (newSize < 0 || newSize == array.size) return;
+            if (newSize < 0 || newSize == array.size) return;
-        std::size_t innerSize = compute_size_na(*type().value.array.type);
+            std::size_t innerSize = compute_size_na(*type().value.array.type);
-        std::byte*  newData   = new std::byte[innerSize * newSize];
+            std::byte*  newData   = new std::byte[innerSize * newSize];
-        std::memcpy(newData, array.data, innerSize * std::min(static_cast<thing_type::u64>(array.size), newSize));
+            std::memcpy(newData, array.data, innerSize * std::min(static_cast<u64>(array.size), newSize));
-        array.size = newSize;
+            array.size = newSize;
-        delete[] array.data;
+            delete[] array.data;
-        array.data = newData;
+            array.data = newData;
+        } break;
+        case thing_type::String: {
+            auto& string = get<struct string>();
+            if (newSize < 0 || newSize == string.size) return;
+            u8* newData = new u8[newSize];
+            std::memcpy(newData, string.data, std::min(static_cast<u64>(string.size), newSize));
+            string.size = newSize;
+            delete[] string.data;
+            string.data = newData;
+        } break;
+        default: throw bad_thing_access();
+        }
     }
 
-    thing at(thing_type::u64 index) const {
+    thing at(u64 index) const {
-        if (!is(thing_type::Array)) throw bad_thing_access();
+        thing ref       = { m_allocator };
-
-        thing ref       = {};
         ref.m_reference = true;
-        ref.m_size      = compute_size_na(*type().value.array.type);
+        ref.m_size      = compute_size_na(*(ref.m_type = &inner_type()));
 
-        if (type().value.array.size == 0) {
+        switch (type().type) {
-            auto& array = get<dynamic_array>();
+        case thing_type::String: {
-            if (index < 0 || index >= array.size) throw std::out_of_range("index out of range");
+            auto& string = get<struct string>();
+            if (index < 0 || index >= string.size) throw std::out_of_range("index out of range");
 
-            ref.m_type = type().value.array.type;
+            ref.m_data = reinterpret_cast<std::byte*>(string.data + index);
-            ref.m_data = array.data + (index * ref.m_size);
             return ref;
         }
+        case thing_type::Array: {
+            if (type().value.array.size == 0) {
+                auto& array = get<dynamic_array>();
+                if (index < 0 || index >= array.size) throw std::out_of_range("index out of range");
 
-        if (index < 0 || index >= type().value.array.size) throw std::out_of_range("index out of range");
+                ref.m_data = array.data + (index * ref.m_size);
+                return ref;
+            }
 
-        ref.m_type = type().value.array.type;
+            if (index < 0 || index >= type().value.array.size) throw std::out_of_range("index out of range");
-        ref.m_data = m_data + (index * ref.m_size);
+            ref.m_data = m_data + (index * ref.m_size);
-        return ref;
+            return ref;
+        }
+        case thing_type::Slice: {
+            const auto& slice = get<struct slice>();
+            if (index < 0 || index >= slice.length) throw std::out_of_range("index out of range");
+            ref.m_data = slice.data + (index * ref.m_size);
+            return ref;
+        }
+        default: throw bad_thing_access();
+        }
     }
 
-    thing_type::u64 length() const {
+    thing slice(u64 begin, u64 len) const {
-        if (!is(thing_type::Array)) throw bad_thing_access();
+        auto& inner = inner_type();
-        return type().value.array.size == 0 ? get<dynamic_array>().size : type().value.array.size;
+
+        thing_type sliceType;
+        sliceType.type             = thing_type::Slice;
+        sliceType.value.slice.type = &inner;
+
+        thing slice = { sliceType, m_allocator };
+        auto& data  = slice.get<struct slice>();
+
+        if (begin >= length()) throw std::out_of_range("begin index out of range");
+        len = std::min(len, length() - begin);
+
+        switch (type().type) {
+        case thing_type::String: {
+            data.data = reinterpret_cast<std::byte*>(get<struct string>().data);
+        } break;
+        case thing_type::Array: {
+            data.data = ((type().value.array.size != 0) ? m_data : get<dynamic_array>().data);
+        } break;
+        case thing_type::Slice: {
+            data.data = get<struct slice>().data;
+        } break;
+        default: throw bad_thing_access();
+        }
+
+        data.data  += (compute_size_na(inner) * begin);
+        data.length = len;
+        return slice;
+    }
+
+    u64 length() const {
+        switch (type().type) {
+        case thing_type::String: return get<struct string>().size;
+        case thing_type::Array:
+            return type().value.array.size == 0 ? get<dynamic_array>().size : type().value.array.size;
+        case thing_type::Slice: return get<struct slice>().length;
+        default: throw bad_thing_access();
+        }
     }
 
     template <typename T, typename = std::enable_if_t<std::is_integral_v<T>>>
@@ -547,13 +680,80 @@ public:
         case thing_type::U16:
         case thing_type::U32:
         case thing_type::U64: std::memcpy(m_data, rhs.m_data, m_size); return;
+        case thing_type::String:
         case thing_type::Ptr:
         case thing_type::Ref:
-        case thing_type::Array: throw std::runtime_error("unimplemented");
+        case thing_type::Array:
+        case thing_type::Slice: throw std::runtime_error("unimplemented");
         case thing_type::Count: break;
         }
         throw std::runtime_error("unreachable");
     }
+
+    void assign(const thing& rhs) {
+        if (type() != rhs.type()) throw std::runtime_error("thing type mismatch");
+        // TODO: Move this to another function
+        switch (type().type) {
+        case thing_type::S8:
+        case thing_type::S16:
+        case thing_type::S32:
+        case thing_type::S64:
+        case thing_type::U8:
+        case thing_type::U16:
+        case thing_type::U32:
+        case thing_type::U64: std::memcpy(m_data, rhs.m_data, m_size); return;
+        case thing_type::Ptr:
+        case thing_type::Ref:
+        case thing_type::Array:
+        case thing_type::Slice: throw std::runtime_error("unimplemented");
+        case thing_type::Count: break;
+        }
+        throw std::runtime_error("unreachable");
+    }
+
+    template <typename T>
+    void assign(const T& value) {
+        if constexpr (detail::cassignable_to_thing<T, thing>::value) {
+            detail::thing_traits<T>::assign_to(*this, value);
+        } else {
+            get<T>() = value;
+        }
+    }
+
+    template <typename T>
+    void assign(T&& value) { // NOLINT
+        if constexpr (detail::massignable_to_thing<T, thing>::value) {
+            detail::thing_traits<T>::assign_to(*this, std::move(value)); // NOLINT
+        } else {
+            get<T>() = std::move(value); // NOLINT
+        }
+    }
+public:
+    iterator begin() {
+        switch (type().type) {
+        case thing_type::String: return { this, reinterpret_cast<std::byte*>(get<struct string>().data) };
+        case thing_type::Array: return { this, (type().value.array.size == 0) ? get<dynamic_array>().data : m_data };
+        case thing_type::Slice: return { this, get<struct slice>().data };
+        default: throw bad_thing_access();
+        }
+    }
+
+    iterator end() { return begin() + length(); }
+
+    const_iterator cbegin() const {
+        switch (type().type) {
+        case thing_type::String: return { this, reinterpret_cast<std::byte*>(get<struct string>().data) };
+        case thing_type::Array: return { this, (type().value.array.size == 0) ? get<dynamic_array>().data : m_data };
+        case thing_type::Slice: return { this, get<struct slice>().data };
+        default: throw bad_thing_access();
+        }
+    }
+
+    const_iterator cend() const { return cbegin() + length(); }
+
+    const_iterator begin() const { return cbegin(); }
+
+    const_iterator end() const { return cend(); }
 private:
     static void copy_list(const thing_type& arrayType, void* dst, const void* src) {
         if (arrayType.type != thing_type::Array || arrayType.value.array.type == nullptr)
@@ -588,8 +788,10 @@ private:
         case thing_type::U16:
         case thing_type::U32:
         case thing_type::U64:
+        case thing_type::String:
         case thing_type::Ptr:
-        case thing_type::Ref: std::memcpy(dst, src, size * elementSize); return;
+        case thing_type::Ref:
+        case thing_type::Slice: std::memcpy(dst, src, size * elementSize); return;
         case thing_type::Array:
             for (std::size_t i = 0; i < size; ++i) {
                 copy_list(*innerType.value.array.type,
@@ -604,18 +806,20 @@ private:
 private:
     static std::size_t compute_size_na(const thing_type& type) {
         switch (type.type) {
-        case thing_type::S8: return sizeof(thing_type::s8);
+        case thing_type::S8: return sizeof(s8);
-        case thing_type::S16: return sizeof(thing_type::s16);
+        case thing_type::S16: return sizeof(s16);
-        case thing_type::S32: return sizeof(thing_type::s32);
+        case thing_type::S32: return sizeof(s32);
-        case thing_type::S64: return sizeof(thing_type::s64);
+        case thing_type::S64: return sizeof(s64);
-        case thing_type::U8: return sizeof(thing_type::u8);
+        case thing_type::U8: return sizeof(u8);
-        case thing_type::U16: return sizeof(thing_type::u16);
+        case thing_type::U16: return sizeof(u16);
-        case thing_type::U32: return sizeof(thing_type::u32);
+        case thing_type::U32: return sizeof(u32);
-        case thing_type::U64: return sizeof(thing_type::u64);
+        case thing_type::U64: return sizeof(u64);
+        case thing_type::String: return sizeof(string);
         case thing_type::Ptr: return sizeof(void*);
         case thing_type::Array:
             return type.value.array.size == 0 ? sizeof(dynamic_array)
                                               : compute_size_na(*type.value.array.type) * type.value.array.size;
+        case thing_type::Slice: return sizeof(struct slice);
         case thing_type::Ref:
         case thing_type::Count: break;
         }
@@ -629,14 +833,14 @@ private:
     template <typename Func>
     decltype(auto) visit_primitive(Func&& func) const {
         switch (type().type) {
-        case thing_type::S8: return std::forward<Func>(func)(get<thing_type::s8>());
+        case thing_type::S8: return std::forward<Func>(func)(get<s8>());
-        case thing_type::S16: return std::forward<Func>(func)(get<thing_type::s16>());
+        case thing_type::S16: return std::forward<Func>(func)(get<s16>());
-        case thing_type::S32: return std::forward<Func>(func)(get<thing_type::s32>());
+        case thing_type::S32: return std::forward<Func>(func)(get<s32>());
-        case thing_type::S64: return std::forward<Func>(func)(get<thing_type::s64>());
+        case thing_type::S64: return std::forward<Func>(func)(get<s64>());
-        case thing_type::U8: return std::forward<Func>(func)(get<thing_type::u8>());
+        case thing_type::U8: return std::forward<Func>(func)(get<u8>());
-        case thing_type::U16: return std::forward<Func>(func)(get<thing_type::u16>());
+        case thing_type::U16: return std::forward<Func>(func)(get<u16>());
-        case thing_type::U32: return std::forward<Func>(func)(get<thing_type::u32>());
+        case thing_type::U32: return std::forward<Func>(func)(get<u32>());
-        case thing_type::U64: return std::forward<Func>(func)(get<thing_type::u64>());
+        case thing_type::U64: return std::forward<Func>(func)(get<u64>());
         default: throw bad_thing_access();
         }
     }
@@ -723,33 +927,19 @@ private:
 
             thing res = { thing_type{ resultType }, m_allocator };
             switch (resultType) {
-            case thing_type::S8:
+            case thing_type::S8: res.get<s8>() = Op{}(cast_to<s8>(), rhs.cast_to<s8>()); return res;
-                res.get<thing_type::s8>() = Op{}(cast_to<thing_type::s8>(), rhs.cast_to<thing_type::s8>());
+            case thing_type::S16: res.get<s16>() = Op{}(cast_to<s16>(), rhs.cast_to<s16>()); return res;
-                return res;
+            case thing_type::S32: res.get<s32>() = Op{}(cast_to<s32>(), rhs.cast_to<s32>()); return res;
-            case thing_type::S16:
+            case thing_type::S64: res.get<s64>() = Op{}(cast_to<s64>(), rhs.cast_to<s64>()); return res;
-                res.get<thing_type::s16>() = Op{}(cast_to<thing_type::s16>(), rhs.cast_to<thing_type::s16>());
+            case thing_type::U8: res.get<u8>() = Op{}(cast_to<u8>(), rhs.cast_to<u8>()); return res;
-                return res;
+            case thing_type::U16: res.get<u16>() = Op{}(cast_to<u16>(), rhs.cast_to<u16>()); return res;
-            case thing_type::S32:
+            case thing_type::U32: res.get<u32>() = Op{}(cast_to<u32>(), rhs.cast_to<u32>()); return res;
-                res.get<thing_type::s32>() = Op{}(cast_to<thing_type::s32>(), rhs.cast_to<thing_type::s32>());
+            case thing_type::U64: res.get<u64>() = Op{}(cast_to<u64>(), rhs.cast_to<u64>()); return res;
-                return res;
+            case thing_type::String:
-            case thing_type::S64:
-                res.get<thing_type::s64>() = Op{}(cast_to<thing_type::s64>(), rhs.cast_to<thing_type::s64>());
-                return res;
-            case thing_type::U8:
-                res.get<thing_type::u8>() = Op{}(cast_to<thing_type::u8>(), rhs.cast_to<thing_type::u8>());
-                return res;
-            case thing_type::U16:
-                res.get<thing_type::u16>() = Op{}(cast_to<thing_type::u16>(), rhs.cast_to<thing_type::u16>());
-                return res;
-            case thing_type::U32:
-                res.get<thing_type::u32>() = Op{}(cast_to<thing_type::u32>(), rhs.cast_to<thing_type::u32>());
-                return res;
-            case thing_type::U64:
-                res.get<thing_type::u64>() = Op{}(cast_to<thing_type::u64>(), rhs.cast_to<thing_type::u64>());
-                return res;
             case thing_type::Ptr: // TODO: Pointer arithmetics
             case thing_type::Ref:
             case thing_type::Array:
+            case thing_type::Slice:
             case thing_type::Count: break;
             }
             throw std::runtime_error("unreachable");
@@ -774,17 +964,57 @@ private:
         m_data = nullptr;
         m_type = nullptr;
     }
+
+    thing_type& inner_type() const {
+        switch (type().type) {
+        case thing_type::String: {
+            static thing_type s_inner = { thing_type::U8 };
+            return s_inner;
+        }
+        case thing_type::Array: return *type().value.array.type;
+        case thing_type::Slice: return *type().value.slice.type;
+        default: throw bad_thing_access();
+        }
+    }
 private:
     // A flag indicating whether the thing instance owns the data, or not.
     bool m_reference = false;
 
-    thing_type* m_type = nullptr;
+    const thing_type* m_type = nullptr;
-    std::size_t m_size = 0;
+    std::size_t       m_size = 0;
-    std::byte*  m_data = nullptr;
+    std::byte*        m_data = nullptr;
 
     allocator_type m_allocator;
 };
 
+namespace detail {
+
+template <>
+struct thing_traits<std::string_view> {
+    template <template <typename...> class Allocator>
+    static void assign_to(thing<Allocator>& thing, const std::string_view& value) {
+        using Thing = furvm::thing<Allocator>;
+
+        auto& string = thing.template get<typename Thing::string>();
+        string.data  = new furvm::u8[string.size = value.length()];
+        std::memcpy(string.data, value.data(), value.length());
+    }
+};
+
+template <>
+struct thing_traits<std::string> {
+    template <template <typename...> class Allocator>
+    static void assign_to(thing<Allocator>& thing, const std::string& value) {
+        using Thing = furvm::thing<Allocator>;
+
+        auto& string = thing.template get<typename Thing::string>();
+        string.data  = new furvm::u8[string.size = value.length()];
+        std::memcpy(string.data, value.data(), value.length());
+    }
+};
+
+} // namespace detail
+
 } // namespace furvm
 
 #endif // FURVM_THING_HPP

include/furvm/types.hpp

@@ -0,0 +1,226 @@
+#ifndef FURVM_TYPES_HPP
+#define FURVM_TYPES_HPP
+
+#include "furvm/fwd.hpp"
+
+#include <cstdint>
+#include <limits>
+#include <stdexcept>
+#include <type_traits>
+#include <utility>
+
+namespace furvm {
+
+using s8  = std::int8_t;
+using s16 = std::int16_t;
+using s32 = std::int32_t;
+using s64 = std::int64_t;
+using u8  = std::uint8_t;
+using u16 = std::uint16_t;
+using u32 = std::uint32_t;
+using u64 = std::uint64_t;
+
+struct thing_type {
+    struct array_value {
+        thing_type* type;
+        std::size_t size;
+    };
+
+    struct slice_value {
+        thing_type* type;
+    };
+
+    enum type { // NOLINT
+        S8 = 0,
+        S16,
+        S32,
+        S64,
+        U8,
+        U16,
+        U32,
+        U64,
+        String,
+        Ptr,
+        Ref,
+        Array,
+        Slice,
+
+        Count,
+    } type = Count;
+    union value {
+        std::nullptr_t null = nullptr;
+        thing_type*    typeRef;
+        array_value    array;
+        slice_value    slice;
+
+        value() = default;
+
+        value(thing_type* type)
+          : typeRef(type) {}
+
+        value(thing_type* type, std::size_t size)
+          : array({}) {
+            array.type = type;
+            array.size = size;
+        }
+    } value;
+
+    static constexpr thing_type_id INVALID_ID = std::numeric_limits<thing_type_id>::max();
+
+    thing_type_id id = INVALID_ID;
+
+    bool operator==(const thing_type& other) const {
+        if (type != other.type) return false;
+        switch (type) {
+        case S8:
+        case S16:
+        case S32:
+        case S64:
+        case U8:
+        case U16:
+        case U32:
+        case U64:
+        case String: return true;
+        case Ptr:
+        case Ref: return *value.typeRef == *other.value.typeRef;
+        case Array: return *value.array.type == *other.value.array.type && value.array.size == other.value.array.size;
+        case Slice: return *value.slice.type == *other.value.slice.type;
+        case Count: break;
+        }
+        return false;
+    }
+
+    bool operator!=(const thing_type& other) const { return !this->operator==(other); }
+
+    static bool is_primitive(enum type type) {
+        switch (type) {
+        case S8:
+        case S16:
+        case S32:
+        case S64:
+        case U8:
+        case U16:
+        case U32:
+        case U64: return true;
+        case String:
+        case Ptr:
+        case Ref:
+        case Array:
+        case Slice: return false;
+        case Count: break;
+        }
+        throw std::runtime_error("unreachable");
+    }
+
+    static std::size_t primitive_size(enum type type) {
+        switch (type) {
+        case thing_type::S8: return sizeof(s8);
+        case thing_type::S16: return sizeof(s16);
+        case thing_type::S32: return sizeof(s32);
+        case thing_type::S64: return sizeof(s64);
+        case thing_type::U8: return sizeof(u8);
+        case thing_type::U16: return sizeof(u16);
+        case thing_type::U32: return sizeof(u32);
+        case thing_type::U64: return sizeof(u64);
+        case thing_type::String:
+        case Ptr:
+        case Ref:
+        case Array:
+        case Slice: return 0;
+        case Count: break;
+        }
+        throw std::runtime_error("unreachable");
+    }
+};
+
+namespace detail {
+
+template <typename T, typename = void>
+struct overrides_thing_type_matching : std::false_type {};
+
+template <typename T>
+struct overrides_thing_type_matching<T, std::void_t<decltype(T::matches(std::declval<const thing_type&>()))>>
+  : std::is_same<decltype(T::matches(std::declval<const thing_type&>())), bool> {};
+
+template <typename T>
+struct thing_traits {
+    bool operator()(const thing_type& type) const {
+        if constexpr (overrides_thing_type_matching<T>::value) {
+            return T::matches(type);
+        } else {
+            return false;
+        }
+    }
+};
+
+template <>
+struct thing_traits<s8> {
+    bool operator()(const thing_type& type) const { return type.type == thing_type::S8; }
+};
+
+template <>
+struct thing_traits<u8> {
+    bool operator()(const thing_type& type) const { return type.type == thing_type::U8; }
+};
+
+template <>
+struct thing_traits<s16> {
+    bool operator()(const thing_type& type) const { return type.type == thing_type::S16; }
+};
+
+template <>
+struct thing_traits<u16> {
+    bool operator()(const thing_type& type) const { return type.type == thing_type::U16; }
+};
+
+template <>
+struct thing_traits<s32> {
+    bool operator()(const thing_type& type) const { return type.type == thing_type::S32; }
+};
+
+template <>
+struct thing_traits<u32> {
+    bool operator()(const thing_type& type) const { return type.type == thing_type::U32; }
+};
+
+template <>
+struct thing_traits<s64> {
+    bool operator()(const thing_type& type) const { return type.type == thing_type::S64; }
+};
+
+template <>
+struct thing_traits<u64> {
+    bool operator()(const thing_type& type) const { return type.type == thing_type::U64; }
+};
+
+template <typename Inner>
+struct thing_traits<Inner*> {
+    bool operator()(const thing_type& type) const {
+        return (type.type == thing_type::Ptr || type.type == thing_type::Ref) &&
+               thing_traits<Inner>{}(*type.value.typeRef);
+    }
+};
+
+template <typename T, typename Thing, typename = void>
+struct cassignable_to_thing : std::false_type {};
+
+template <typename T, typename Thing>
+struct cassignable_to_thing<T,
+    Thing,
+    std::void_t<decltype(std::declval<thing_traits<T>>().assign_to(std::declval<Thing&>(), std::declval<const T&>()))>>
+  : std::true_type {};
+
+template <typename T, typename Thing, typename = void>
+struct massignable_to_thing : std::false_type {};
+
+template <typename T, typename Thing>
+struct massignable_to_thing<T,
+    Thing,
+    std::void_t<decltype(std::declval<thing_traits<T>>().assign_to(std::declval<Thing&>(), std::declval<T&&>()))>>
+  : std::true_type {};
+
+} // namespace detail
+
+} // namespace furvm
+
+#endif // FURVM_TYPES_HPP

src/disfuras/CMakeLists.txt

@@ -0,0 +1,4 @@
+file(GLOB_RECURSE DISFURAS_SRCS "${CMAKE_SOURCE_DIR}/src/disfuras/**.cpp")
+add_executable(disfuras ${DISFURAS_SRCS})
+target_include_directories(disfuras PRIVATE ${CMAKE_SOURCE_DIR}/include/)
+target_link_libraries(disfuras PUBLIC furlang libfurc libfurvm)

src/furas/CMakeLists.txt

@@ -0,0 +1,5 @@
+file(GLOB_RECURSE FURAS_SRCS "${CMAKE_SOURCE_DIR}/src/furas/**.cpp")
+file(GLOB_RECURSE FURAS_HDRS "${CMAKE_SOURCE_DIR}/include/furas/**.hpp")
+add_executable(furas ${FURAS_SRCS} ${FURAS_HDRS})
+target_include_directories(furas PUBLIC ${CMAKE_SOURCE_DIR}/include/)
+target_link_libraries(furas PRIVATE furlang libfurvm)

src/furas/gen.cpp

@@ -4,6 +4,7 @@
 #include "furvm/function.hpp"
 #include "furvm/fwd.hpp"
 #include "furvm/instruction.hpp"
+#include "furvm/module.hpp"
 
 #include <cassert>
 #include <cstdint>
@@ -24,6 +25,7 @@ namespace {
 // NOLINTBEGIN
 std::unordered_map<enum token::type, furvm::instruction_t> instructions = {
     { token::Array, furvm::instruction_t::Array },
+    { token::Slice, furvm::instruction_t::Slice },
     { token::Get, furvm::instruction_t::Get },
     { token::Set, furvm::instruction_t::Set },
     { token::Drop, furvm::instruction_t::Drop },
@@ -77,6 +79,7 @@ const char* token_type(enum token::type type) {
     case token::Allocate: return "allocate";
     case token::Push: return "push";
     case token::Array: return "array";
+    case token::Slice: return "slice";
     case token::Get: return "get";
     case token::Set: return "set";
     case token::Drop: return "drop";
@@ -160,6 +163,8 @@ struct mod_context {
         case furvm::mod_type::Array:
             return lhs->value.array.size == rhs->value.array.size &&
                    compare_types(mod.type_at(lhs->value.array.typeId), mod.type_at(rhs->value.array.typeId));
+        case furvm::mod_type::Slice:
+            return compare_types(mod.type_at(lhs->value.slice.typeId), mod.type_at(rhs->value.slice.typeId));
         case furvm::mod_type::Import:
             return lhs->value.imprt.modId == rhs->value.imprt.modId &&
                    lhs->value.imprt.typeId == rhs->value.imprt.typeId;
@@ -252,6 +257,15 @@ struct mod_context {
 
             return mod.emplace_type(inner.id(), size->value.uint);
         }
+        case token::Slice: {
+            auto result = next_token(lexer);
+
+            if (!result) throw std::runtime_error("error");
+
+            auto inner = eat_type(lexer, result.value);
+
+            return mod.emplace_type(furvm::mod_type::Slice, inner.id());
+        }
         default: throw std::runtime_error("error");
         }
     }
@@ -463,6 +477,7 @@ struct mod_context {
         }
 
         case token::Array:
+        case token::Slice:
         case token::Get:
         case token::Set:
         case token::Drop:

src/furas/lexer.cpp

@@ -19,7 +19,7 @@ token_r lexer::next_token() {
     // TODO: Add support for single-line comments
     // TODO: Add support for multi-line comments
 
-    if (m_cursor >= m_content.size()) return token_r{ lexer_error{ lexer_error::EndOfFile, location() } };
+    if (m_cursor >= m_content.size()) return token_r::error(lexer_error{ lexer_error::EndOfFile, location() });
 
     // TODO: Add support for negative integers (I am positive thanks to stasiu :v:)
     // TODO: Add support for hexadecimal and binary numeric literals
@@ -43,6 +43,7 @@ token_r lexer::next_token() {
 
         { "push", token::Push },
         { "array", token::Array },
+        { "slice", token::Slice },
         { "get", token::Get },
         { "set", token::Set },
         { "drop", token::Drop },
@@ -92,9 +93,9 @@ token_r lexer::next_token() {
     case '.': ++m_cursor; return { token::Dot };
     case ':': ++m_cursor; return { token::Colon };
     default:
-        return token_r{
+        return token_r::error(lexer_error{ lexer_error::UnknownCharacter,
-            lexer_error{ lexer_error::UnknownCharacter, location(), "Unknown character '"s + m_content[m_cursor] + "'" }
+            location(),
-        };
+            "Unknown character '"s + m_content[m_cursor] + "'" });
     }
 }
 

src/furc/CMakeLists.txt

@@ -0,0 +1,15 @@
+file(GLOB_RECURSE FURC_SRCS "${CMAKE_SOURCE_DIR}/src/furc/**.cpp")
+file(GLOB_RECURSE FURC_HDRS "${CMAKE_SOURCE_DIR}/include/furc/**.hpp")
+add_library(libfurc ${FURC_SRCS} ${FURC_HDRS})
+target_include_directories(libfurc PUBLIC ${CMAKE_SOURCE_DIR}/include/)
+target_compile_definitions(libfurc PRIVATE LIBFURC)
+set_target_properties(libfurc PROPERTIES PREFIX "")
+target_link_libraries(libfurc PUBLIC furlang libfurvm)
+add_executable(furc "${CMAKE_SOURCE_DIR}/src/furc/main.cpp")
+target_link_libraries(furc PRIVATE libfurc)
+
+include(GoogleTest)
+
+add_executable(furc_tests "${CMAKE_SOURCE_DIR}/test/furc/ssa.cpp")
+target_link_libraries(furc_tests PRIVATE libfurc GTest::gtest_main)
+gtest_discover_tests(furc_tests)

src/furc/back/furvm/target.cpp

@@ -0,0 +1,20 @@
+#include "furc/back/furvm/target.hpp"
+
+#include "furvm/function.hpp"
+
+#include <stdexcept>
+
+namespace furc {
+
+furvm::mod furvm_generator::generate(const ir_module& mod) {
+    if (!mod.variables.empty()) throw std::runtime_error("global variables are not supported for furvm yet");
+
+    furvm::mod furvmMod;
+    for (const auto& func : mod.functions) {
+        furvmMod.emplace_function(furvm::function_sig{ {}, {} }, furvmMod.bytecode().size());
+    }
+
+    return furvmMod;
+}
+
+} // namespace furc

src/furc/main.cpp

@@ -1,6 +1,10 @@
+#ifndef LIBFURC
+
 #include "furc/front/lexer.hpp"
 #include "furc/front/parser.hpp"
 #include "furc/middle/ir.hpp"
+#include "furc/middle/reg_gen.hpp"
+#include "furc/middle/ssa.hpp"
 #include "furlang/arena.hpp"
 
 int main(void) {
@@ -16,6 +20,12 @@ int main(void) {
     furc::lexer     lexer    = { "<AK>", content };
     furc::parser    parser   = { std::move(lexer), arena };
     furc::ir_module irModule = furc::ir_generator::generate(parser.parse());
+    for (auto& func : irModule.functions) {
+        furc::ssa     ssa(*func);
+        furc::reg_gen gen(*func, ssa);
+    }
 
     return 0;
 }
+
+#endif // LIBFURC

src/furc/middle/ssa.cpp

@@ -0,0 +1,307 @@
+/**
+ * Sources:
+ *  - Practical Improvements to the Construction and Deconstruction of Static Single Assignment Form:
+ * https://web.archive.org/web/20100607003509/http://www.cs.rice.edu/~harv/my_papers/ssa.pdf
+ *  - A Simple, Fast Dominance Algorithm:
+ * https://www.researchgate.net/publication/2569680_A_Simple_Fast_Dominance_Algorithm
+ */
+
+#include "furc/middle/ssa.hpp"
+
+#include "furc/middle/ir.hpp"
+
+#include <algorithm>
+#include <cstddef>
+#include <limits>
+#include <stack>
+#include <stdexcept>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+
+namespace furc {
+
+void ssa::compute_cfg(const std::vector<ir_basic_block>& irBlocks, std::vector<cfg_block>& cfgBlocks) {
+    cfgBlocks.resize(irBlocks.size());
+
+    for (std::size_t i = 0; i < irBlocks.size(); ++i) {
+        const auto& block = irBlocks[i];
+        if (block.instructions.empty()) continue;
+
+        const auto& termInstr = block.instructions.back();
+        switch (termInstr.type) {
+        case ir_instruction::Branch: {
+            const auto& dst = termInstr.destination.value();
+            assert(dst.type == ir_operand::Block);
+            cfgBlocks[dst.value.block].preds.insert(i);
+            cfgBlocks[i].sucs.insert(dst.value.block);
+        } break;
+        case ir_instruction::BranchCond: {
+            const auto& dst = termInstr.destination.value();
+            assert(dst.type == ir_operand::BlockPair);
+            cfgBlocks[dst.value.blockPair.first].preds.insert(i);
+            cfgBlocks[dst.value.blockPair.second].preds.insert(i);
+            cfgBlocks[i].sucs.insert(dst.value.blockPair.first);
+            cfgBlocks[i].sucs.insert(dst.value.blockPair.second);
+        } break;
+        default: break;
+        }
+    }
+}
+
+void ssa::collect_registers(const std::vector<ir_basic_block>& irBlocks,
+    std::vector<register_info>&                                registers,
+    std::unordered_set<std::uint64_t>&                         globals) {
+    for (std::size_t i = 0; i < irBlocks.size(); ++i) {
+        const auto& block = irBlocks[i];
+        for (const auto& instr : block.instructions) {
+            for (const auto& src : instr.sources) {
+                if (src.type != ir_operand::Register) continue;
+                const auto& reg = registers.at(src.value.reg.name);
+                if (reg.sites.find(i) != reg.sites.end()) continue;
+                globals.insert(src.value.reg.name);
+            }
+            if (!instr.destination.has_value() || instr.destination->type != ir_operand::Register) continue;
+            registers[instr.destination->value.reg.name].sites.insert(i);
+        }
+    }
+}
+
+void ssa::build_dtree(const std::vector<cfg_block>& cfgBlocks,
+    std::vector<ssa_block>&                         ssaBlocks,
+    const std::vector<std::size_t>&                 order) {
+    ssaBlocks[order.front()].idom = order.front();
+
+    bool changed = true;
+    while (changed) {
+        changed = false;
+        for (auto it = order.begin() + 1; it != order.end(); ++it) {
+            static constexpr std::uint64_t INVALID = std::numeric_limits<std::uint64_t>::max();
+
+            std::uint64_t newIdom = -1;
+            bool          found   = false;
+
+            for (std::uint64_t pred : cfgBlocks[*it].preds) {
+                if (ssaBlocks[pred].idom == INVALID) continue;
+                newIdom = found ? intersect(ssaBlocks, pred, newIdom) : pred;
+                found   = true;
+            }
+            if (ssaBlocks[*it].idom != newIdom) {
+                ssaBlocks[*it].idom = newIdom;
+                changed             = true;
+            }
+        }
+    }
+}
+
+void ssa::compute_dfrontiers(const std::vector<cfg_block>& cfgBlocks, std::vector<ssa_block>& ssaBlocks) {
+    for (std::uint64_t i = 0; i < ssaBlocks.size(); ++i) {
+        if (cfgBlocks[i].preds.size() < 2) continue;
+        const auto& cfgBlock = cfgBlocks[i];
+        auto&       ssaBlock = ssaBlocks[i];
+
+        for (std::uint64_t worker : cfgBlock.preds) {
+            while (worker != ssaBlock.idom) {
+                ssaBlocks[worker].df.insert(i);
+                worker = ssaBlocks[worker].idom;
+            }
+        }
+    }
+}
+
+void ssa::compute_rpo(std::vector<cfg_block>& cfgBlocks,
+    std::vector<ssa_block>&                   ssaBlocks,
+    std::vector<std::size_t>&                 order) {
+    std::unordered_set<std::size_t> visited;
+    if (!cfgBlocks.empty()) rpo_dfs(visited, order, 0, cfgBlocks);
+    std::reverse(order.begin(), order.end());
+    ssaBlocks.resize(cfgBlocks.size());
+    for (std::size_t i = 0; i < order.size(); ++i) {
+        ssaBlocks[order[i]].order = i;
+    }
+}
+
+void ssa::ssaification(std::vector<ir_basic_block>& irBlocks,
+    const std::vector<cfg_block>&                   cfgBlocks,
+    const std::vector<ssa_block>&                   ssaBlocks,
+    const std::vector<register_info>&               registers,
+    const std::unordered_set<std::uint64_t>&        globals) {
+    std::vector<std::uint64_t> worklist;
+
+    for (std::uint64_t i = 0; i < registers.size(); ++i) {
+        const auto& reg = registers[i];
+        if (reg.sites.size() < 2 || globals.find(i) == globals.end()) continue;
+        worklist.insert(worklist.end(), reg.sites.begin(), reg.sites.end());
+
+        std::unordered_set<std::uint64_t> done;
+        while (!worklist.empty()) {
+            const auto blockIdx = worklist.back();
+            worklist.pop_back();
+
+            for (auto frontier : ssaBlocks[blockIdx].df) {
+                if (done.find(frontier) != done.end()) continue;
+                done.insert(frontier);
+
+                auto&          target = irBlocks[frontier];
+                ir_instruction instr  = { ir_instruction::Phi, ir_operand{ ir_operand::Register, i } };
+                for (const auto& pred : cfgBlocks[frontier].preds)
+                    instr.sources.emplace_back(ir_operand::PhiPair, i, pred);
+                target.instructions.emplace(target.instructions.begin(), std::move(instr));
+
+                if (reg.sites.find(frontier) == reg.sites.end()) worklist.push_back(frontier);
+            }
+        }
+    }
+}
+
+void ssa::rename(std::vector<ir_basic_block>& irBlocks,
+    std::size_t                               regCount,
+    const std::vector<cfg_block>&             cfgBlocks,
+    std::vector<ssa_block>&                   ssaBlocks,
+    const std::vector<std::uint64_t>&         order) {
+    std::vector<std::uint64_t>             counters;
+    std::vector<std::stack<std::uint64_t>> stacks;
+
+    counters.resize(regCount);
+    stacks.resize(regCount);
+
+    for (auto it = order.begin() + 1; it != order.end(); ++it) {
+        std::uint64_t parent = ssaBlocks[*it].idom;
+        if (parent != std::numeric_limits<std::uint64_t>::max()) ssaBlocks[parent].children.emplace(*it);
+    }
+
+    rename_rec(counters, stacks, irBlocks, cfgBlocks, ssaBlocks, order.front());
+}
+
+void ssa::rename_rec(std::vector<std::uint64_t>& counters,
+    std::vector<std::stack<std::uint64_t>>&      stacks,
+    std::vector<ir_basic_block>&                 irBlocks,
+    const std::vector<cfg_block>&                cfgBlocks,
+    const std::vector<ssa_block>&                ssaBlocks,
+    std::size_t                                  blockIdx) {
+    std::unordered_map<std::uint64_t, std::size_t> pushed;
+
+    auto& block = irBlocks[blockIdx];
+    for (auto& instr : block.instructions) {
+        if (instr.type == ir_instruction::Phi) {
+            auto reg = instr.destination->value.reg.name;
+            stacks[reg].push(instr.destination->value.reg.ver = counters[reg]++);
+            ++pushed[reg];
+            continue;
+        }
+
+        for (auto& op : instr.sources) {
+            if (op.type != ir_operand::Register) continue;
+            auto reg         = op.value.reg.name;
+            op.value.reg.ver = stacks[reg].top();
+        }
+
+        if (!instr.destination.has_value() || instr.destination->type != ir_operand::Register) continue;
+        auto reg = instr.destination->value.reg.name;
+        stacks[reg].push(instr.destination->value.reg.ver = counters[reg]++);
+        ++pushed[reg];
+    }
+
+    for (auto succIdx : cfgBlocks[blockIdx].sucs) {
+        auto& succ = irBlocks[succIdx];
+        for (auto& instr : succ.instructions) {
+            if (instr.type != ir_instruction::Phi) break;
+            for (auto& op : instr.sources) {
+                if (op.value.phiPair.block != blockIdx) continue;
+                op.value.phiPair.reg.ver = stacks[op.value.phiPair.reg.name].top();
+            }
+        }
+    }
+
+    for (std::uint64_t child : ssaBlocks[blockIdx].children)
+        rename_rec(counters, stacks, irBlocks, cfgBlocks, ssaBlocks, child);
+
+    for (auto [reg, count] : pushed)
+        while ((count--) > 0)
+            stacks[reg].pop();
+}
+
+void ssa::rpo_dfs(std::unordered_set<std::size_t>& visited,
+    std::vector<std::size_t>&                      order,
+    std::size_t                                    block,
+    const std::vector<cfg_block>&                  blocks) {
+    visited.insert(block);
+    for (auto succ : blocks[block].sucs) {
+        if (visited.find(succ) != visited.end()) continue;
+        rpo_dfs(visited, order, succ, blocks);
+    }
+    order.push_back(block);
+}
+
+std::size_t ssa::intersect(std::vector<ssa_block>& m_blocks, std::size_t b1, std::size_t b2) {
+    while (b1 != b2) {
+        while (m_blocks[b1].order > m_blocks[b2].order)
+            b1 = m_blocks[b1].idom;
+        while (m_blocks[b2].order > m_blocks[b1].order)
+            b2 = m_blocks[b2].idom;
+    }
+    return b1;
+}
+
+// // 5. Renaming
+// std::vector<std::uint64_t>             counters;
+// std::vector<std::stack<std::uint64_t>> stacks;
+//
+// counters.resize(func.regCount);
+// stacks.resize(func.regCount);
+//
+// for (std::size_t i = 1; i < order.size(); ++i) {
+// std::size_t parent = blocks[order[i]].idom;
+// if (parent != std::numeric_limits<std::size_t>::max()) blocks[parent].children.emplace(order[i]);
+// }
+//
+// auto rename = [&counters, &stacks, &blocks, &func](auto& self, std::size_t blockIdx) -> void {
+// std::unordered_map<std::size_t, std::size_t> pushed;
+//
+// auto& block = func.blocks[blockIdx];
+// for (auto& instr : block.instructions) {
+// if (instr.type == ir_instruction::Phi) {
+// auto reg                         = instr.destination->value.reg.name;
+// auto idx                         = counters[reg]++;
+// instr.destination->value.reg.ver = idx;
+// stacks[reg].push(idx);
+// ++pushed[reg];
+// continue;
+// }
+//
+// for (auto& op : instr.sources) {
+// if (op.type != ir_operand::Register) continue;
+// auto reg         = op.value.reg.name;
+// op.value.reg.ver = stacks[reg].top();
+// }
+//
+// if (!instr.destination.has_value() || instr.destination->type != ir_operand::Register) continue;
+// auto reg                         = instr.destination->value.reg.name;
+// auto idx                         = counters[reg]++;
+// instr.destination->value.reg.ver = idx;
+// stacks[reg].push(idx);
+// ++pushed[reg];
+// }
+//
+// for (auto succIdx : blocks[blockIdx].sucs) {
+// auto& succ = func.blocks[succIdx];
+// for (auto& instr : succ.instructions) {
+// if (instr.type != ir_instruction::Phi) break;
+// for (auto& op : instr.sources) {
+// if (op.value.phiPair.block != blockIdx) continue;
+// op.value.phiPair.reg.ver = stacks[op.value.phiPair.reg.name].top();
+// }
+// }
+// }
+//
+// for (std::size_t child : blocks[blockIdx].children)
+// self(self, child);
+//
+// for (auto [reg, count] : pushed)
+// while (count--)
+// stacks[reg].pop();
+// };
+// rename(rename, order.front());
+// }
+
+} // namespace furc

src/furdb/CMakeLists.txt

@@ -0,0 +1,5 @@
+file(GLOB_RECURSE FURDB_SRCS "${CMAKE_SOURCE_DIR}/src/furdb/**.cpp")
+file(GLOB_RECURSE FURDB_HDRS "${CMAKE_SOURCE_DIR}/include/furdb/**.hpp")
+add_executable(furdb ${FURDB_SRCS} ${FURDB_HDRS})
+target_include_directories(furdb PRIVATE ${CMAKE_SOURCE_DIR}/include/)
+target_link_libraries(furdb PUBLIC furlang libfurc libfurvm isocline)

src/furdb/command.cpp

@@ -107,6 +107,11 @@ static void print_type(const furvm::thing_type& type) {
             std::cout << type.value.array.size;
         std::cout << ")";
         break;
+    case furvm::thing_type::Slice:
+        std::cout << "slice(";
+        print_type(*type.value.slice.type);
+        std::cout << ")";
+        break;
     case furvm::thing_type::Count: break;
     }
 }
@@ -116,21 +121,26 @@ static void print_thing(const furvm::thing<>& thing) {
     print_type(thing.type());
     std::cout << ") ";
     switch (thing.type().type) {
-    case furvm::thing_type::S8: std::cout << std::to_string(thing.get<furvm::thing_type::s8>()); break;
+    case furvm::thing_type::S8: std::cout << std::to_string(thing.get<furvm::s8>()); break;
-    case furvm::thing_type::S16: std::cout << thing.get<furvm::thing_type::s16>(); break;
+    case furvm::thing_type::S16: std::cout << thing.get<furvm::s16>(); break;
-    case furvm::thing_type::S32: std::cout << thing.get<furvm::thing_type::s32>(); break;
+    case furvm::thing_type::S32: std::cout << thing.get<furvm::s32>(); break;
-    case furvm::thing_type::S64: std::cout << thing.get<furvm::thing_type::s64>(); break;
+    case furvm::thing_type::S64: std::cout << thing.get<furvm::s64>(); break;
-    case furvm::thing_type::U8: std::cout << std::to_string(thing.get<furvm::thing_type::u8>()); break;
+    case furvm::thing_type::U8: std::cout << std::to_string(thing.get<furvm::u8>()); break;
-    case furvm::thing_type::U16: std::cout << thing.get<furvm::thing_type::u16>(); break;
+    case furvm::thing_type::U16: std::cout << thing.get<furvm::u16>(); break;
-    case furvm::thing_type::U32: std::cout << thing.get<furvm::thing_type::u32>(); break;
+    case furvm::thing_type::U32: std::cout << thing.get<furvm::u32>(); break;
-    case furvm::thing_type::U64: std::cout << thing.get<furvm::thing_type::u64>(); break;
+    case furvm::thing_type::U64: std::cout << thing.get<furvm::u64>(); break;
     case furvm::thing_type::Ptr: std::cout << thing.get<const void*>(); break;
-    case furvm::thing_type::Array: {
+    case furvm::thing_type::Array:
-        if (thing.type().value.array.size == 0) std::cout << thing.length();
+    case furvm::thing_type::Slice: {
-        std::cout << "{ ";
+        if (thing.length() == 0) {
-        for (std::size_t i = 0; i < thing.length(); ++i) {
+            std::cout << "{}";
-            if (i > 0) std::cout << ", ";
+            break;
-            print_thing(thing.at(i));
+        }
+
+        std::cout << '(' << thing.length() << ") { ";
+        for (const auto& el : thing) {
+            print_thing(el);
+            std::cout << ", ";
         }
         std::cout << " }";
     } break;

src/furdb/context.cpp

@@ -49,6 +49,8 @@ void context::print_instruction() const {
         "push",
         // Array
         "array",
+        // Slice
+        "slice",
         // Get
         "get",
         // Set

src/furdb/main.cpp

@@ -15,17 +15,17 @@ static void print_thing(const furvm::thing<>& thing) {
     using namespace furvm;
 
     switch (thing.type().type) {
-    case thing_type::S8: std::cout << thing.cast_to<thing_type::s16>(); break;
+    case thing_type::S8: std::cout << thing.cast_to<s16>(); break;
-    case thing_type::S16: std::cout << thing.get<thing_type::s16>(); break;
+    case thing_type::S16: std::cout << thing.get<s16>(); break;
-    case thing_type::S32: std::cout << thing.get<thing_type::s32>(); break;
+    case thing_type::S32: std::cout << thing.get<s32>(); break;
-    case thing_type::S64: std::cout << thing.get<thing_type::s64>(); break;
+    case thing_type::S64: std::cout << thing.get<s64>(); break;
-    case thing_type::U8: std::cout << thing.get<thing_type::u8>(); break;
+    case thing_type::U8: std::cout << thing.get<u8>(); break;
-    case thing_type::U16: std::cout << thing.get<thing_type::u16>(); break;
+    case thing_type::U16: std::cout << thing.get<u16>(); break;
-    case thing_type::U32: std::cout << thing.get<thing_type::u32>(); break;
+    case thing_type::U32: std::cout << thing.get<u32>(); break;
-    case thing_type::U64: std::cout << thing.get<thing_type::u64>(); break;
+    case thing_type::U64: std::cout << thing.get<u64>(); break;
     case thing_type::Array:
         std::cout << "{ ";
-        for (thing_type::u64 i = 0; i < thing.length(); ++i) {
+        for (u64 i = 0; i < thing.length(); ++i) {
             if (i > 0) std::cout << ", ";
             print_thing(thing.at(i));
         }

src/furlang/CMakeLists.txt

@@ -0,0 +1,4 @@
+file(GLOB_RECURSE FURLANG_SRCS "${CMAKE_SOURCE_DIR}/src/furlang/**.cpp")
+file(GLOB_RECURSE FURLANG_HDRS "${CMAKE_SOURCE_DIR}/include/furlang/**.hpp")
+add_library(furlang STATIC ${FURLANG_SRCS} ${FURLANG_HDRS})
+target_include_directories(furlang PUBLIC ${CMAKE_SOURCE_DIR}/include/)

src/furlang/serialization/io.cpp

@@ -0,0 +1,137 @@
+#include "furlang/serialization/io.hpp"
+
+#include <cstring>
+
+namespace furlang::serialization {
+
+result<error> byte_writer::write_s8(std::int8_t value) {
+    if (m_endianness == endianness::Little)
+        write_integral_le(value);
+    else
+        write_integral_be(value);
+    return {};
+}
+
+result<error> byte_writer::write_u8(std::uint8_t value) {
+    if (m_endianness == endianness::Little)
+        write_integral_le(value);
+    else
+        write_integral_be(value);
+    return {};
+}
+
+result<error> byte_writer::write_s16(std::int16_t value) {
+    if (m_endianness == endianness::Little)
+        write_integral_le(value);
+    else
+        write_integral_be(value);
+    return {};
+}
+
+result<error> byte_writer::write_u16(std::uint16_t value) {
+    if (m_endianness == endianness::Little)
+        write_integral_le(value);
+    else
+        write_integral_be(value);
+    return {};
+}
+
+result<error> byte_writer::write_s32(std::int32_t value) {
+    if (m_endianness == endianness::Little)
+        write_integral_le(value);
+    else
+        write_integral_be(value);
+    return {};
+}
+
+result<error> byte_writer::write_u32(std::uint32_t value) {
+    if (m_endianness == endianness::Little)
+        write_integral_le(value);
+    else
+        write_integral_be(value);
+    return {};
+}
+
+result<error> byte_writer::write_s64(std::int64_t value) {
+    if (m_endianness == endianness::Little)
+        write_integral_le(value);
+    else
+        write_integral_be(value);
+    return {};
+}
+
+result<error> byte_writer::write_u64(std::uint64_t value) {
+    if (m_endianness == endianness::Little)
+        write_integral_le(value);
+    else
+        write_integral_be(value);
+    return {};
+}
+
+result<error> byte_writer::write_string(const char* string) {
+    write_u16(std::strlen(string));
+    m_bytes.insert(m_bytes.end(), string, string + std::strlen(string));
+    return {};
+}
+
+result<error> byte_writer::write_string(std::string_view string) {
+    write_u16(string.length());
+    m_bytes.insert(m_bytes.end(), string.begin(), string.end());
+    return {};
+}
+
+result<error> byte_writer::write_string(const std::string& string) {
+    write_u16(string.length());
+    m_bytes.insert(m_bytes.end(), string.begin(), string.end());
+    return {};
+}
+
+result<error, std::int8_t> byte_reader::read_s8() {
+    return m_endianness == endianness::Little ? read_integral_le<std::int8_t>() : read_integral_be<std::int8_t>();
+}
+
+result<error, std::uint8_t> byte_reader::read_u8() {
+    return m_endianness == endianness::Little ? read_integral_le<std::uint8_t>() : read_integral_be<std::uint8_t>();
+}
+
+result<error, std::int16_t> byte_reader::read_s16() {
+    return m_endianness == endianness::Little ? read_integral_le<std::int16_t>() : read_integral_be<std::int16_t>();
+}
+
+result<error, std::uint16_t> byte_reader::read_u16() {
+    return m_endianness == endianness::Little ? read_integral_le<std::uint16_t>() : read_integral_be<std::uint16_t>();
+}
+
+result<error, std::int32_t> byte_reader::read_s32() {
+    return m_endianness == endianness::Little ? read_integral_le<std::int32_t>() : read_integral_be<std::int32_t>();
+}
+
+result<error, std::uint32_t> byte_reader::read_u32() {
+    return m_endianness == endianness::Little ? read_integral_le<std::uint32_t>() : read_integral_be<std::uint32_t>();
+}
+
+result<error, std::int64_t> byte_reader::read_s64() {
+    return m_endianness == endianness::Little ? read_integral_le<std::int64_t>() : read_integral_be<std::int64_t>();
+}
+
+result<error, std::uint64_t> byte_reader::read_u64() {
+    return m_endianness == endianness::Little ? read_integral_le<std::uint64_t>() : read_integral_be<std::uint64_t>();
+}
+
+result<error, std::string> byte_reader::read_string() {
+    std::string str;
+    auto        length = read_u16();
+    if (length.has_error()) return length;
+    str.resize(length.value());
+    if (m_offset + str.length() >= m_length)
+        return result<error, std::string>::error(error{ error_code::EndOfFile, "", m_length });
+    str.assign(reinterpret_cast<const char*>(m_bytes) + m_offset, str.length());
+    m_offset += str.length();
+    return str;
+}
+
+std::size_t byte_reader::offset() const {
+    return m_offset;
+}
+
+} // namespace furlang::serialization

src/furvm/CMakeLists.txt

@@ -1,16 +1,16 @@
-file(GLOB_RECURSE FURVM_SRCS "src/**.cpp")
+file(GLOB_RECURSE FURVM_SRCS "${CMAKE_SOURCE_DIR}/src/furvm/**.cpp")
-file(GLOB_RECURSE FURVM_HDRS "include/**.hpp")
+file(GLOB_RECURSE FURVM_HDRS "${CMAKE_SOURCE_DIR}/include/furvm/**.hpp")
 add_library(libfurvm ${FURVM_SRCS} ${FURVM_HDRS})
-target_include_directories(libfurvm PUBLIC include/)
+target_include_directories(libfurvm PUBLIC ${CMAKE_SOURCE_DIR}/include/)
 target_compile_definitions(libfurvm PRIVATE LIBFURVM)
 set_target_properties(libfurvm PROPERTIES PREFIX "")
 target_link_libraries(libfurvm PUBLIC furlang)
-add_executable(furvm src/main.cpp)
+add_executable(furvm "${CMAKE_SOURCE_DIR}/src/furvm/main.cpp")
 target_link_libraries(furvm PRIVATE libfurvm)
 
 include(GoogleTest)
 
-file(GLOB_RECURSE FURVM_TESTS "test/**.cpp")
+file(GLOB_RECURSE FURVM_TESTS "${CMAKE_SOURCE_DIR}/test/furvm/**.cpp")
 add_executable(furvm_tests ${FURVM_TESTS})
 target_link_libraries(furvm_tests PRIVATE libfurvm GTest::gtest_main)
-gtest_discover_tests(furvm_tests)
+gtest_discover_tests(furvm_tests)

src/furvm/executor.cpp

@@ -31,13 +31,16 @@ thing_type executor::thing_type_impl(mod_h mod, mod_type type) const {
     case thing_type::U8:
     case thing_type::U16:
     case thing_type::U32:
-    case thing_type::U64: return { static_cast<enum thing_type::type>(type.type) };
+    case thing_type::U64:
+    case thing_type::String: return { static_cast<enum thing_type::type>(type.type) };
     case thing_type::Ptr: return { thing_type::Ptr, mod_to_thing_type(mod, *mod->type_at(type.value.typeRef)) };
     case thing_type::Ref: return { thing_type::Ref, mod_to_thing_type(mod, *mod->type_at(type.value.typeRef)) };
     case thing_type::Array: {
         return { static_cast<enum thing_type::type>(type.type),
             { mod_to_thing_type(mod, *mod->type_at(type.value.array.typeId)), type.value.array.size } };
     }
+    case thing_type::Slice:
+        return { thing_type::Slice, mod_to_thing_type(mod, *mod->type_at(type.value.slice.typeId)) };
     case thing_type::Count: break;
     }
     throw std::runtime_error("invalid thing type");
@@ -58,32 +61,36 @@ bool executor::compare_thing_types(const thing_type& lhs, const thing_type& rhs)
     case thing_type::U8:
     case thing_type::U16:
     case thing_type::U32:
-    case thing_type::U64: return true;
+    case thing_type::U64:
+    case thing_type::String: return true;
     case thing_type::Ptr:
     case thing_type::Ref: return compare_thing_types(*lhs.value.typeRef, *rhs.value.typeRef);
     case thing_type::Array:
         return lhs.value.array.size == rhs.value.array.size &&
                compare_thing_types(*lhs.value.array.type, *rhs.value.array.type);
+    case thing_type::Slice: return compare_thing_types(*lhs.value.slice.type, *rhs.value.slice.type);
     case thing_type::Count: break;
     }
     throw std::runtime_error("unreachable");
 }
 
 void executor::push_frame(const mod_h& mod, function function) {
+    m_stackStorage.push_frame();
+
     mod_h modInst = mod;
     while (function.type() == function_t::Import) {
         modInst  = m_context->at(function.imp().mod);
         function = *modInst->function_at(function.imp().function);
     }
 
-    auto                 signature = function.signature();
+    auto                     signature = function.signature();
-    std::vector<thing<>> args;
+    std::vector<stack_thing> args;
     args.reserve(signature.params.size());
     for (const auto& param : signature.params) {
         auto arg = pop_thing();
-        if (compare_thing_types(arg.type(), *mod_to_thing_type(mod, *param)))
+        if (!compare_thing_types(arg.type(), *mod_to_thing_type(mod, *param)))
             throw std::runtime_error("function argument type mismatch");
-        args.push_back(std::move(arg));
+        args.emplace_back(std::move(arg));
     }
 
     struct thing_type* returnType = nullptr;
@@ -117,7 +124,7 @@ struct executor::frame executor::pop_frame() {
     if (m_frames.empty()) throw stack_underflow();
     struct executor::frame frame = m_frames.top();
     m_frames.pop();
-    std::optional<thing<>> returnValue;
+    std::optional<stack_thing> returnValue;
     if (frame.returnType != nullptr) {
         returnValue = pop_thing();
         if (returnValue->type() != *frame.returnType) throw std::runtime_error("function return type mismatch");
@@ -132,6 +139,8 @@ struct executor::frame executor::pop_frame() {
     }
     m_flags = m_flags & ~executor_flags::JustHit;
 
+    m_stackStorage.pop_frame();
+
     return frame;
 }
 
@@ -139,49 +148,49 @@ struct executor::frame executor::top_frame() const {
     return m_frames.top();
 }
 
-thing<>& executor::push_thing(thing<>&& thing) {
+executor::stack_thing& executor::push_thing(stack_thing&& thing) {
     return m_stack.emplace_back(std::move(thing));
 }
 
-thing<>& executor::push_thing(const thing<>& thing) {
+executor::stack_thing& executor::push_thing(const stack_thing& thing) {
     return m_stack.emplace_back(thing);
 }
 
-thing<> executor::pop_thing() {
+executor::stack_thing executor::pop_thing() {
     if (m_frames.top().stackBase >= m_stack.size()) throw stack_underflow();
     auto top = std::move(m_stack.back());
     m_stack.pop_back();
     return std::move(top);
 }
 
-thing<>& executor::top_thing() {
+executor::stack_thing& executor::top_thing() {
     if (m_frames.top().stackBase >= m_stack.size()) throw stack_underflow();
     return m_stack.back();
 }
 
-const thing<>& executor::top_thing() const {
+const executor::stack_thing& executor::top_thing() const {
     if (m_frames.top().stackBase >= m_stack.size()) throw stack_underflow();
     return m_stack.back();
 }
 
-void executor::store_thing(variable_t variable, const thing<>& thing) {
+void executor::store_thing(variable_t variable, const stack_thing& thing) {
     auto& frame = m_frames.top();
     if (frame.variables.size() <= variable) frame.variables.resize(variable + 1);
     frame.variables[variable] = thing;
 }
 
-void executor::store_thing(variable_t variable, thing<>&& thing) {
+void executor::store_thing(variable_t variable, stack_thing&& thing) {
     auto& frame = m_frames.top();
     if (frame.variables.size() <= variable) frame.variables.resize(variable + 1);
     frame.variables[variable] = std::move(thing);
 }
 
-thing<>& executor::load_thing(variable_t variable) {
+executor::stack_thing& executor::load_thing(variable_t variable) {
     auto& frame = m_frames.top();
     return frame.variables[variable];
 }
 
-const thing<>& executor::load_thing(variable_t variable) const {
+const executor::stack_thing& executor::load_thing(variable_t variable) const {
     const auto& frame = m_frames.top();
     return frame.variables[variable];
 }
@@ -204,30 +213,53 @@ void executor::step() {
     switch (instr.type) {
     case instruction_t::NoOperation: break;
     case instruction_t::PushS8: {
-        push_thing({ (struct thing_type){ thing_type::S8 } }).get<thing_type::s8>() = instr.arg.s8;
+        push_thing({ (struct thing_type){ thing_type::S8 }, { m_stackStorage } }).get<s8>() = instr.arg.s8;
     } break;
     case instruction_t::PushU8: {
-        push_thing({ (struct thing_type){ thing_type::U8 } }).get<thing_type::u8>() = instr.arg.u8;
+        push_thing({ (struct thing_type){ thing_type::U8 }, { m_stackStorage } }).get<u8>() = instr.arg.u8;
     } break;
     case instruction_t::PushS16: {
-        push_thing({ (struct thing_type){ thing_type::S16 } }).get<thing_type::s16>() = instr.arg.s16;
+        push_thing({ (struct thing_type){ thing_type::S16 }, { m_stackStorage } }).get<s16>() = instr.arg.s16;
     } break;
     case instruction_t::PushU16: {
-        push_thing({ (struct thing_type){ thing_type::U16 } }).get<thing_type::u16>() = instr.arg.u16;
+        push_thing({ (struct thing_type){ thing_type::U16 }, { m_stackStorage } }).get<u16>() = instr.arg.u16;
     } break;
     case instruction_t::PushS32: {
-        push_thing({ (struct thing_type){ thing_type::S32 } }).get<thing_type::s32>() = instr.arg.s8; // NOLINT
+        push_thing({ (struct thing_type){ thing_type::S32 }, { m_stackStorage } }).get<s32>() = instr.arg.s8; // NOLINT
     } break;
     case instruction_t::PushU32: {
-        push_thing({ (struct thing_type){ thing_type::U32 } }).get<thing_type::u32>() =
+        push_thing({ (struct thing_type){ thing_type::U32 }, { m_stackStorage } }).get<u32>() =
-            static_cast<thing_type::u32>(instr.arg.u8);
+            static_cast<u32>(instr.arg.u8);
+    } break;
+    case instruction_t::PushConstant: {
+        auto constant = frame.mod->constant_at(instr.arg.u16);
+        switch (constant.type) {
+        case constant::S32:
+            push_thing({ (struct thing_type){ thing_type::S32 }, { m_stackStorage } }).get<s32>() =
+                constant.s32; // NOLINT
+            break;
+        case constant::U32:
+            push_thing({ (struct thing_type){ thing_type::U32 }, { m_stackStorage } }).get<u32>() =
+                constant.u32; // NOLINT
+            break;
+        case constant::S64:
+            push_thing({ (struct thing_type){ thing_type::S64 }, { m_stackStorage } }).get<s64>() =
+                constant.s64; // NOLINT
+            break;
+        case constant::U64:
+            push_thing({ (struct thing_type){ thing_type::U64 }, { m_stackStorage } }).get<u64>() =
+                constant.u64; // NOLINT
+            break;
+        case constant::String: throw std::runtime_error("unimplemented");
+        default: throw std::runtime_error("invalid constant");
+        }
     } break;
     case instruction_t::Array: {
         const auto& type = *mod_to_thing_type(frame.mod, *frame.mod->type_at(instr.arg.u32));
         if (type.type != thing_type::Array || type.value.array.type == nullptr || type.value.array.type == &type)
             throw std::runtime_error("invalid array type");
 
-        auto& array = push_thing({ type });
+        auto& array = push_thing({ type, { m_stackStorage } });
 
         if (type.value.array.size == 0) {
             auto         sizeThing = pop_thing();
@@ -235,6 +267,12 @@ void executor::step() {
             array.resize(size);
         }
     } break;
+    case instruction_t::Slice: {
+        auto length = pop_thing();
+        auto start  = pop_thing();
+        auto array  = pop_thing();
+        push_thing(array.slice(start.integer(), length.integer()));
+    } break;
     case instruction_t::Get: {
         auto index = pop_thing();
         auto array = pop_thing();
@@ -262,7 +300,7 @@ void executor::step() {
         push_thing(top_thing());
     } break;
     case instruction_t::Reference: {
-        push_thing(thing<>::make_reference(pop_thing()));
+        push_thing(stack_thing::make_reference(pop_thing(), { m_stackStorage }));
     } break;
     case instruction_t::Add: {
         auto rhs = pop_thing();
@@ -321,12 +359,13 @@ void executor::step() {
     } break;
     case instruction_t::Pointerof: {
         auto thing = pop_thing();
-        push_thing({ (struct thing_type){ thing_type::Ptr, m_context->tt_store().at(thing.type().id) } }).get<void*>() =
+        push_thing(
-            thing.raw();
+            { (struct thing_type){ thing_type::Ptr, m_context->tt_store().at(thing.type().id) }, { m_stackStorage } })
+            .get<void*>() = thing.raw();
     } break;
     case instruction_t::Sizeof: {
         auto  thing = pop_thing();
-        auto& size  = push_thing({ (struct thing_type){ thing_type::U64 } });
+        auto& size  = push_thing({ (struct thing_type){ thing_type::U64 }, { m_stackStorage } });
         switch (thing.type().type) {
         case thing_type::S8:
         case thing_type::S16:
@@ -335,34 +374,32 @@ void executor::step() {
         case thing_type::U8:
         case thing_type::U16:
         case thing_type::U32:
-        case thing_type::U64:
+        case thing_type::U64: size.get<u64>() = static_cast<u64>(thing_type::primitive_size(thing.type().type)); break;
-            size.get<thing_type::u64>() = static_cast<thing_type::u64>(thing_type::primitive_size(thing.type().type));
+        case thing_type::Ptr: size.get<u64>() = static_cast<u64>(sizeof(void*)); break;
-            break;
-        case thing_type::Ptr: size.get<thing_type::u64>() = static_cast<thing_type::u64>(sizeof(void*)); break;
         case thing_type::Array:
             /* TODO: Return actual memory size of the array
              * By the memory size I mean the length times sizeof single element.
              */
-            size.get<thing_type::u64>() = thing.length();
+            size.get<u64>() = thing.length();
             break;
         default: throw std::runtime_error("unreachable");
         }
     } break;
     case instruction_t::Lengthof: {
-        auto thing                                                                    = pop_thing();
+        auto thing                                                                            = pop_thing();
-        push_thing({ (struct thing_type){ thing_type::U64 } }).get<thing_type::u64>() = thing.length();
+        push_thing({ (struct thing_type){ thing_type::U64 }, { m_stackStorage } }).get<u64>() = thing.length();
     } break;
     case instruction_t::Load: {
-        push_thing(std::move(thing<>::make_reference(load_thing(instr.arg.u16))));
+        push_thing(std::move(stack_thing::make_reference(load_thing(instr.arg.u16), { m_stackStorage })));
     } break;
     case instruction_t::Store: {
         store_thing(instr.arg.u16, std::move(pop_thing()));
     } break;
     case instruction_t::LoadGlobal: {
-        push_thing(thing<>::make_reference(frame.mod->load_global_variable(instr.arg.u16)));
+        push_thing(stack_thing::make_reference(frame.mod->load_global_variable(instr.arg.u16), { m_stackStorage }));
     } break;
     case instruction_t::StoreGlobal: {
-        frame.mod->store_global_variable(instr.arg.u16, std::move(pop_thing()));
+        frame.mod->store_global_variable(instr.arg.u16, pop_thing());
     } break;
     case instruction_t::Call: {
         push_frame(frame.mod, *frame.mod->function_at(instr.arg.u16));
@@ -377,7 +414,6 @@ void executor::step() {
         pop_frame();
         if (m_frames.empty()) m_flags = m_flags | executor_flags::Done;
     } break;
-    case instruction_t::PushConstant: throw std::runtime_error("unimplemented");
     default: throw std::runtime_error("unknown instruction");
     }
 }

src/furvm/instruction.cpp

@@ -22,7 +22,7 @@ const std::size_t instruction_argument::s_sizes[instruction_argument::Count] = {
     // U32
     1,
     // Constant:
-    4,
+    2,
     // Type:
     4,
     // Variable:
@@ -83,6 +83,8 @@ const instruction_argument_t instruction::s_arguments[instruction::Count] = {
     instruction_argument::Constant,
     // Array:
     instruction_argument::Type,
+    // Slice:
+    instruction_argument::None,
     // Get:
     instruction_argument::None,
     // Set:

src/furvm/main.cpp

@@ -14,17 +14,25 @@ static void print_thing(const furvm::thing<>& thing) {
     using namespace furvm;
 
     switch (thing.type().type) {
-    case thing_type::S8: std::cout << thing.cast_to<thing_type::s16>(); break;
+    case thing_type::S8: std::cout << thing.cast_to<s16>(); break;
-    case thing_type::S16: std::cout << thing.get<thing_type::s16>(); break;
+    case thing_type::S16: std::cout << thing.get<s16>(); break;
-    case thing_type::S32: std::cout << thing.get<thing_type::s32>(); break;
+    case thing_type::S32: std::cout << thing.get<s32>(); break;
-    case thing_type::S64: std::cout << thing.get<thing_type::s64>(); break;
+    case thing_type::S64: std::cout << thing.get<s64>(); break;
-    case thing_type::U8: std::cout << thing.get<thing_type::u8>(); break;
+    case thing_type::U8: std::cout << thing.get<u8>(); break;
-    case thing_type::U16: std::cout << thing.get<thing_type::u16>(); break;
+    case thing_type::U16: std::cout << thing.get<u16>(); break;
-    case thing_type::U32: std::cout << thing.get<thing_type::u32>(); break;
+    case thing_type::U32: std::cout << thing.get<u32>(); break;
-    case thing_type::U64: std::cout << thing.get<thing_type::u64>(); break;
+    case thing_type::U64: std::cout << thing.get<u64>(); break;
     case thing_type::Array:
         std::cout << "{ ";
-        for (thing_type::u64 i = 0; i < thing.length(); ++i) {
+        for (u64 i = 0; i < thing.length(); ++i) {
+            if (i > 0) std::cout << ", ";
+            print_thing(thing.at(i));
+        }
+        std::cout << " }";
+        break;
+    case thing_type::Slice:
+        std::cout << "Slice [" << thing.length() << "] { ";
+        for (u64 i = 0; i < thing.length(); ++i) {
             if (i > 0) std::cout << ", ";
             print_thing(thing.at(i));
         }

src/furvm/module.cpp

@@ -16,6 +16,19 @@ std::ostream& mod::serialize(std::ostream& os) const {
     os.write(MAGIC, sizeof(MAGIC));
     detail::serialize(os, std::uint32_t(0)); // version
 
+    detail::serialize(os, static_cast<constant_index>(m_constants.size()));
+    for (const auto& constant : m_constants) {
+        detail::serialize(os, constant.type);
+        switch (constant.type) {
+        case constant::S32:
+        case constant::U32: detail::serialize(os, constant.u32); break;
+        case constant::S64:
+        case constant::U64: detail::serialize(os, constant.u64); break;
+        case constant::String: throw std::runtime_error("unimplemented");
+        default: throw std::runtime_error("unreachable");
+        }
+    }
+
     mod_type_id typeCount = mod_type_id(m_types.cend() - m_types.cbegin());
     detail::serialize(os, typeCount);
     for (mod_type_id id = 0; id < typeCount; ++id) {
@@ -41,6 +54,9 @@ std::ostream& mod::serialize(std::ostream& os) const {
             detail::serialize(os, type.value.array.typeId);
             detail::serialize(os, type.value.array.size);
         } break;
+        case mod_type::Slice: {
+            detail::serialize(os, type.value.slice.typeId);
+        } break;
         case mod_type::Import: {
             detail::serialize(os, type.value.imprt.modId);
             detail::serialize(os, type.value.imprt.typeId);
@@ -104,6 +120,22 @@ mod mod::load(std::istream& is) {
 
     mod mod;
 
+    constant_index constantCount = 0;
+    detail::load(is, constantCount);
+    mod.m_constants.reserve(constantCount);
+    for (; constantCount != 0; --constantCount) {
+        constant constant{};
+        detail::load(is, reinterpret_cast<std::uint32_t&>(constant.type));
+        switch (constant.type) {
+        case constant::S32:
+        case constant::U32: detail::load(is, constant.u32); break;
+        case constant::S64:
+        case constant::U64: detail::load(is, constant.u64); break;
+        case constant::String: throw std::runtime_error("unimplemented");
+        default: throw std::runtime_error("unreachable");
+        }
+    }
+
     mod_type_id typeCount = 0;
     detail::load(is, typeCount);
     for (mod_type_id id = 0; id < typeCount; ++id) {
@@ -140,6 +172,11 @@ mod mod::load(std::istream& is) {
             detail::load(is, size);
             mod.emplace_type(id, typeId, size).dispatch();
         } break;
+        case mod_type::Slice: {
+            mod_type_id typeId = 0;
+            detail::load(is, typeId);
+            mod.emplace_type(id, mod_type::Slice, typeId).dispatch();
+        } break;
         case mod_type::Import: {
             std::string modName;
             detail::load(is, modName);

test/furc/ssa.cpp

@@ -0,0 +1,141 @@
+// NOLINTBEGIN(readability-identifier-naming)
+
+#include "gtest/gtest.h"
+#include <furc/middle/ir.hpp>
+#include <furc/middle/ssa.hpp>
+#include <unordered_set>
+#include <vector>
+
+namespace furc::test {
+
+class SsaCfg : public testing::Test {
+public:
+    SsaCfg()
+      : p_context(&p_function) {}
+protected:
+    void compute() { ssa::compute_cfg(p_function.blocks, p_cfgBlocks); }
+protected:
+    std::vector<ssa::cfg_block> p_cfgBlocks;
+
+    ir_function p_function;
+    ir_context  p_context;
+};
+
+TEST_F(SsaCfg, Diamond) {
+    ir_operand null = { ir_operand::Integer, static_cast<std::uint64_t>(0) };
+
+    // Entry
+    p_context.terminate(null, 1, 2);
+    p_context.new_next();
+    // A
+    p_context.terminate(3);
+    p_context.new_next();
+    // B
+    p_context.terminate(3);
+    p_context.new_next();
+    // C
+    p_context.terminate(4);
+    p_context.new_next();
+    // Exit
+    p_context.terminate();
+
+    compute();
+
+    EXPECT_EQ(p_cfgBlocks[0].sucs.size(), 2);
+    EXPECT_NE(p_cfgBlocks[0].sucs.find(1), p_cfgBlocks[0].sucs.end());
+    EXPECT_NE(p_cfgBlocks[0].sucs.find(2), p_cfgBlocks[0].sucs.end());
+    EXPECT_EQ(p_cfgBlocks[3].preds, p_cfgBlocks[0].sucs);
+    EXPECT_EQ(p_cfgBlocks[3].sucs.size(), 1);
+    EXPECT_NE(p_cfgBlocks[3].sucs.find(4), p_cfgBlocks[3].sucs.end());
+}
+
+class SsaDom : public testing::Test {
+public:
+    SsaDom()
+      : p_context(&p_function) {}
+protected:
+    void compute() {
+        ssa::compute_cfg(p_function.blocks, p_cfgBlocks);
+        p_ssaRegisters.resize(p_function.regCount);
+        ssa::collect_registers(p_function.blocks, p_ssaRegisters, p_ssaGlobals);
+
+        std::vector<std::uint64_t> order;
+        ssa::compute_rpo(p_cfgBlocks, p_ssaBlocks, order);
+
+        ssa::build_dtree(p_cfgBlocks, p_ssaBlocks, order);
+        ssa::compute_dfrontiers(p_cfgBlocks, p_ssaBlocks);
+
+        ssa::ssaification(p_function.blocks, p_cfgBlocks, p_ssaBlocks, p_ssaRegisters, p_ssaGlobals);
+        ssa::rename(p_function.blocks, p_function.regCount, p_cfgBlocks, p_ssaBlocks, order);
+    }
+protected:
+    std::vector<ssa::cfg_block>       p_cfgBlocks;
+    std::vector<ssa::ssa_block>       p_ssaBlocks;
+    std::vector<ssa::register_info>   p_ssaRegisters;
+    std::unordered_set<std::uint64_t> p_ssaGlobals;
+
+    ir_function p_function;
+    ir_context  p_context;
+};
+
+TEST_F(SsaDom, Diamond) {
+    ir_operand null = { ir_operand::Integer, static_cast<std::uint64_t>(0) };
+
+    // Entry
+    p_context.terminate(null, 1, 2);
+    p_context.new_next();
+    // A
+    p_context.add_instr(ir_instruction{ ir_instruction::Move,
+        ir_operand{ ir_operand::Register, static_cast<std::uint64_t>(0) },
+        { null } });
+    p_context.terminate(3);
+    p_context.new_next();
+    // B
+    p_context.add_instr(ir_instruction{ ir_instruction::Move,
+        ir_operand{ ir_operand::Register, static_cast<std::uint64_t>(0) },
+        { null } });
+    p_context.terminate(3);
+    p_context.new_next();
+    // C
+    p_context.add_instr(ir_instruction{ ir_instruction::Add,
+        ir_operand{ ir_operand::Register, static_cast<std::uint64_t>(0) },
+        { ir_operand{ ir_operand::Register, static_cast<std::uint64_t>(0) } } });
+    p_context.new_next();
+    // Exit
+    p_context.terminate();
+
+    p_function.regCount = 1;
+
+    compute();
+
+    EXPECT_TRUE(p_ssaBlocks[0].df.empty());
+
+    EXPECT_EQ(p_ssaBlocks[1].idom, 0);
+    EXPECT_EQ(p_ssaBlocks[1].df.size(), 1);
+    EXPECT_NE(p_ssaBlocks[1].df.find(3), p_ssaBlocks[1].df.end());
+
+    EXPECT_EQ(p_ssaBlocks[2].idom, 0);
+    EXPECT_EQ(p_ssaBlocks[2].df.size(), 1);
+    EXPECT_NE(p_ssaBlocks[2].df.find(3), p_ssaBlocks[2].df.end());
+
+    EXPECT_EQ(p_ssaBlocks[3].idom, 0);
+    EXPECT_TRUE(p_ssaBlocks[3].df.empty());
+
+    EXPECT_EQ(p_ssaBlocks[4].idom, 3);
+    EXPECT_TRUE(p_ssaBlocks[4].df.empty());
+
+    // Renaming
+    EXPECT_EQ(p_function.blocks[1].instructions.front(),
+        (ir_instruction{ ir_instruction::Move, ir_operand::reg(0, 3), { null } }));
+    EXPECT_EQ(p_function.blocks[2].instructions.front(),
+        (ir_instruction{ ir_instruction::Move, ir_operand::reg(0, 2), { null } }));
+    EXPECT_EQ(p_function.blocks[3].instructions.front(),
+        (ir_instruction{ ir_instruction::Phi,
+            ir_operand::reg(0, 0),
+            { ir_operand{ ir_operand::PhiPair, ir_operand::value_u::register_s{ 0, 2 }, 2 },
+                ir_operand{ ir_operand::PhiPair, ir_operand::value_u::register_s{ 0, 3 }, 1 } } }));
+}
+
+} // namespace furc::test
+
+// NOLINTEND(readability-identifier-naming)

test/furvm/test.cpp

@@ -0,0 +1,110 @@
+#include "furvm/exceptions.hpp"
+#include "furvm/furvm.hpp"
+#include "furvm/thing.hpp"
+
+#include "gtest/gtest.h" // IWYU pragma: keep
+#include <array>
+
+namespace {
+
+// TODO: Basic program tests (e.g. for loops)
+
+TEST(ThingOps, Add) {
+    furvm::thing lhs{ furvm::thing_type{ furvm::thing_type::U32 } };
+    lhs.get<furvm::u32>() = 6;
+    furvm::thing rhs{ furvm::thing_type{ furvm::thing_type::U32 } };
+    rhs.get<furvm::u32>() = 7;
+
+    auto res = lhs.add(rhs);
+    ASSERT_EQ(res.type().type, furvm::thing_type::U32);
+    EXPECT_EQ(lhs.get<furvm::u32>(), 6);
+    EXPECT_EQ(rhs.get<furvm::u32>(), 7);
+    EXPECT_EQ(res.get<furvm::u32>(), 6 + 7);
+}
+
+TEST(ThingOps, Array) {
+    furvm::thing_type innerType = { furvm::thing_type::U32 };
+
+    static constexpr std::size_t                    LENGTH = 10;
+    static constexpr std::array<furvm::u32, LENGTH> values = { 0, 1, 2, 3, 4, 5, 6, 7, 6, 7 };
+
+    furvm::thing array{ furvm::thing_type{ furvm::thing_type::Array, { &innerType, LENGTH } } };
+    EXPECT_EQ(array.length(), LENGTH);
+    for (std::size_t i = 0; i < LENGTH; ++i) {
+        auto el              = array.at(i);
+        el.get<furvm::u32>() = values[i];
+        EXPECT_EQ(array.at(i).integer(), values[i]);
+    }
+}
+
+TEST(ThingOps, Slice) {
+    furvm::thing_type innerType = { furvm::thing_type::U32 };
+
+    static constexpr std::size_t                    LENGTH = 10;
+    static constexpr std::array<furvm::u32, LENGTH> values = { 0, 1, 2, 3, 4, 5, 6, 7, 6, 7 };
+
+    furvm::thing array{ furvm::thing_type{ furvm::thing_type::Array, { &innerType, LENGTH } } };
+    EXPECT_EQ(array.length(), LENGTH);
+    furvm::thing slice = array.slice(0, LENGTH);
+    EXPECT_EQ(slice.length(), LENGTH);
+    for (std::size_t i = 0; i < LENGTH; ++i) {
+        auto el              = slice.at(i);
+        el.get<furvm::u32>() = values[i];
+        EXPECT_EQ(array.at(i).integer(), values[i]);
+        EXPECT_EQ(slice.at(i).integer(), array.at(i).integer());
+    }
+}
+
+TEST(ThingOps, String) {
+    static constexpr std::string_view STRING = "femboje na topie";
+    static constexpr auto             LENGTH = STRING.length();
+
+    furvm::thing string{ furvm::thing_type{ furvm::thing_type::String } };
+    string.assign(STRING);
+    EXPECT_EQ(string.length(), LENGTH);
+    furvm::thing slice = string.slice(0, LENGTH);
+    EXPECT_EQ(slice.length(), LENGTH);
+    for (std::size_t i = 0; i < LENGTH; ++i) {
+        auto el = slice.at(i);
+        EXPECT_EQ(slice.at(i).get<furvm::u8>(), STRING[i]);
+    }
+}
+
+TEST(ThingOps, Iterators) {
+    furvm::thing_type innerType = { furvm::thing_type::U32 };
+
+    static constexpr std::size_t                    LENGTH = 10;
+    static constexpr std::array<furvm::u32, LENGTH> values = { 0, 1, 2, 3, 4, 5, 6, 7, 6, 7 };
+
+    furvm::thing array{ furvm::thing_type{ furvm::thing_type::Array, { &innerType, LENGTH } } };
+    EXPECT_EQ(array.length(), LENGTH);
+    for (std::size_t i = 0; i < LENGTH; ++i) {
+        auto el              = array.at(i);
+        el.get<furvm::u32>() = values[i];
+        EXPECT_EQ(array.at(i).integer(), values[i]);
+    }
+
+    std::size_t itCount = 0;
+    for (auto it = array.begin(); it != array.end(); ++it, ++itCount) {
+        auto idx = it - array.begin();
+        ASSERT_EQ(idx, itCount);
+        ASSERT_LT(idx, LENGTH);
+        EXPECT_EQ(it->integer(), values[idx]);
+    }
+}
+
+TEST(ThingOps, Access) {
+    furvm::thing thing{ furvm::thing_type{ furvm::thing_type::U8 } };
+    EXPECT_NO_THROW(thing.get<furvm::u8>());
+    EXPECT_THROW(thing.get<furvm::s8>(), furvm::bad_thing_access);
+    EXPECT_THROW(thing.get<furvm::s32>(), furvm::bad_thing_access);
+    EXPECT_THROW(thing.get<void*>(), furvm::bad_thing_access);
+
+    EXPECT_NO_THROW(thing.assign<furvm::u8>(67));
+    EXPECT_THROW(thing.assign<furvm::s32>(1337), furvm::bad_thing_access);
+    EXPECT_EQ(thing.get<furvm::u8>(), 67);
+    EXPECT_NO_THROW(thing.set<furvm::u8>(67)); // He talkin' 'bout sum 6-7 while I want sixty ni-
+    EXPECT_THROW(thing.set<furvm::s32>(1337), furvm::bad_thing_access);
+}
+
+} // namespace