feat: migrate from OpView to DoubleLinkedList<Op*> + multiple

funciton arguments

example.rx

@@ -1,4 +1,5 @@
 extern putchar
+extern iadd
 
 fn hello() {
     local h = 72
@@ -14,5 +15,6 @@ fn hello() {
 
 fn main() {
     hello()
-    putchar(3 * 3 + 1)
+    local newline = iadd(3*3, 1)
+    putchar(newline)
 }

include/codegen/allocator.hpp

@@ -1,66 +0,0 @@
-#pragma once
-#include "prelude/string.hpp"
-#include "codegen/slot.hpp"
-
-#define AVAILABLE_REGISTERS 4
-#define AVAILABLE_STACK_SIZE 4096
-
-template <typename Slot, typename SlotAddr = const StringView &>
-class Allocator
-{
-public:
-    virtual ~Allocator() {};
-
-public:
-    virtual const Slot &Allocate(SlotAddr addr) = 0;
-    virtual const Slot &Resolve(SlotAddr addr) = 0;
-};
-
-class SlotAllocator : public Allocator<IR::IRSlot>
-{
-public:
-    SlotAllocator() = default;
-    ~SlotAllocator() = default;
-
-public:
-    const IR::IRSlot &Allocate(const StringView &addr) override
-    {
-        if (m_regs < AVAILABLE_REGISTERS)
-        {
-            m_slots.Push(IR::IRSlot(addr, m_regs++, IR::IRSlot::Type::REGISTRY));
-            return m_slots.data[m_slots.size - 1];
-        }
-        if (m_offset_counter + 8 <= AVAILABLE_STACK_SIZE)
-        {
-            m_offset_counter += 8;
-            m_slots.Push(IR::IRSlot(addr, m_offset_counter, IR::IRSlot::Type::STACK));
-            return m_slots.data[m_slots.size - 1];
-        }
-        // TODO: proper error handling (stack overflow etc.)
-        assert(0 && "failed to allocate local");
-    }
-
-    const IR::IRSlot &Resolve(const StringView &addr) override
-    {
-        for (size_t i = 0; i < m_slots.size; ++i)
-        {
-            if (m_slots.data[i].GetAddr() == addr)
-            {
-                return m_slots.data[i];
-            }
-        }
-
-        assert(0 && "could not resolve stack offset for specified address");
-    }
-
-public:
-    View<IR::IRSlot> slots() const { return m_slots.view(); }
-
-public:
-    unsigned int GetStackSize() const { return m_offset_counter; }
-
-public:
-    int m_regs = 0;
-    unsigned int m_offset_counter = 0;
-    Builder<IR::IRSlot> m_slots;
-};

include/codegen/codegen.hpp

@@ -1,17 +1,21 @@
-
-// TODO: store all of values, allocated registers, stack offsets in single allocator
-// to be able to find out which kind a specific temp register represent
-
 #pragma once
-#include <cstddef>
+#include "ir/op.hpp"
-#include <cstdarg>
+#include "prelude/linkedlist.hpp"
 #include "prelude/string.hpp"
-#include "ir/ir.hpp"
 
 class CodeGenerator
 {
 public:
-    virtual ~CodeGenerator() {};
+    CodeGenerator() = default;
+    virtual ~CodeGenerator() {}
 
-    virtual void Generate(const char* filename, View<IR::Op*> ops) = 0;
+public:
+    virtual bool Generate(const DoubleLinkedList<IR::Op*>* ops) = 0;
+    StringView GetOutput() { return output().view(); }
+
+protected:
+    StringBuilder& output() { return m_output; }
+
+private:
+    StringBuilder m_output;
 };

include/codegen/fasm_stack.hpp

@@ -1,180 +0,0 @@
-#pragma once
-
-#include "codegen/codegen.hpp"
-#include "ir/slot.hpp"
-#include "ir/value.hpp"
-
-class StackFasmX86_64Generator : public CodeGenerator
-{
-public:
-    ~StackFasmX86_64Generator() override = default;
-
-private:
-    StringView GetTempAddr(IR::ValueHandle *reg)
-    {
-        return std::move((StringBuilder() << reg->Format()).view());
-    }
-
-    StringView GetSlotAddr(const IR::IRSlot &slot)
-    {
-        switch (slot.GetType())
-        {
-        case IR::IRSlot::Type::REGISTRY:
-        {
-            StringBuilder sb;
-            sb.AppendFormat("r%d", slot.GetSlot() + 12); // for r10, r11, r12 etc.
-            return sb.view();
-        }
-        break;
-        case IR::IRSlot::Type::STACK:
-        {
-            StringBuilder sb;
-            sb.AppendFormat("[rbp-%d]", slot.GetSlot()); // for r10, r11, r12 etc.
-            return sb.view();
-        }
-        break;
-        default:
-            assert(0 && "TODO: either unreachable or handle properly");
-        }
-    }
-
-private:
-    void GenerateOp(const IR::Op *op)
-    {
-        switch (op->GetType())
-        {
-        case IR::OpType::EXTERN:
-        {
-            auto extrn = reinterpret_cast<const IR::ExternOp *>(op);
-            auto symbol = extrn->symbol();
-            appendf("extrn '%s' as __%s\n", symbol.c_str(), symbol.c_str());
-            appendf("%s = PLT __%s\n", symbol.c_str(), symbol.c_str());
-        }
-        break;
-        case IR::OpType::FN:
-        {
-            m_allocator = new SlotAllocator();
-
-            auto fn = reinterpret_cast<const IR::FnOp *>(op);
-            auto name = fn->name();
-            appendf("public %s\n", name.c_str());
-            appendf("%s:\n", name.c_str());
-            appendf("push rbp\n");
-            appendf("mov rbp, rsp\n");
-
-            StringBuilder fnOutput;
-            StringBuilder *backup = m_output;
-            m_output = &fnOutput;
-
-            if (fn->params().size > 0)
-            {
-                // TODO: support multiple parameters
-                auto param_slot = m_allocator->Allocate(fn->params().data[0]);
-                appendf("mov %s, rdi\n", GetSlotAddr(param_slot).c_str());
-            }
-            for (auto &fOp : fn->body().ops())
-            {
-                GenerateOp(fOp);
-            }
-
-            int stackSize = m_allocator->GetStackSize();
-            m_output = backup;
-            appendf("sub rsp, %d\n", stackSize);
-            *m_output << fnOutput.c_str();
-
-            appendf("leave\nret\n");
-
-            m_allocator = nullptr;
-        }
-        break;
-        case IR::OpType::CALL:
-        {
-            auto call = reinterpret_cast<const IR::CallOp *>(op);
-            // TODO: support several arguments
-            if (call->args().size == 1)
-            {
-                auto slot = m_allocator->Resolve(GetTempAddr(call->args().data[0]));
-                appendf("mov rdi, %s\n", GetSlotAddr(slot).c_str());
-            }
-            appendf("call %s\n", call->callee().c_str());
-            auto result_slot = m_allocator->Allocate(GetTempAddr(call->result()));
-            appendf("mov %s, rax\n", GetSlotAddr(result_slot).c_str());
-        }
-        break;
-            // case IR::OpType::LOAD_CONST:
-            // {
-            //     auto lc = reinterpret_cast<const IR::LoadConstOp *>(op);
-            //     auto addr = GetTempAddr(lc->result());
-            //     auto slot = m_allocator->Allocate(addr);
-            //     appendf("mov %s, %ld\n", GetSlotAddr(slot).c_str(), lc->value());
-            // }
-            // break;
-        case IR::OpType::STORE:
-        {
-            auto s = reinterpret_cast<const IR::StoreOp *>(op);
-            auto slot = m_allocator->Allocate(s->addr());
-            auto value_slot = m_allocator->Resolve(GetTempAddr(s->src()));
-            appendf("mov rax, %s\n", GetSlotAddr(value_slot).c_str());
-            appendf("mov %s, rax\n", GetSlotAddr(slot).c_str());
-        }
-        break;
-        case IR::OpType::LOAD:
-        {
-            auto l = reinterpret_cast<const IR::LoadOp *>(op);
-            auto value_slot = m_allocator->Allocate(GetTempAddr(l->result()));
-            auto variable_slot = m_allocator->Resolve(l->addr());
-            appendf("mov rax, %s\n", GetSlotAddr(variable_slot).c_str());
-            appendf("mov %s, rax\n", GetSlotAddr(value_slot).c_str());
-        }
-        break;
-        case IR::OpType::ADD:
-        {
-            auto expr = reinterpret_cast<const IR::AddOp *>(op);
-            auto lhs_slot = m_allocator->Resolve(GetTempAddr(expr->lhs()));
-            appendf("mov rax, %s\n", GetSlotAddr(lhs_slot).c_str());
-            auto rhs_slot = m_allocator->Resolve(GetTempAddr(expr->rhs()));
-            appendf("add rax, %s\n", GetSlotAddr(rhs_slot).c_str());
-            auto result_slot = m_allocator->Allocate(GetTempAddr(expr->result()));
-            appendf("mov %s, rax\n", GetSlotAddr(result_slot).c_str());
-        }
-        break;
-        default:
-            appendf("; NOT HANDLED\n; %s\n", op->Format(0).c_str());
-            break;
-        }
-    }
-
-    void appendf(const char *fmt, ...)
-    {
-        assert(m_output != nullptr && "nowhere to write");
-        va_list args;
-        va_start(args, fmt);
-        m_output->VAppendFormat(fmt, args);
-        va_end(args);
-    }
-
-public:
-    StringView GetOutput() { return m_output->view(); }
-
-private:
-    StringBuilder *m_output = nullptr;
-
-public:
-    void Generate(const char *filename, View<IR::Op *> ops) override
-    {
-        m_output = new StringBuilder();
-        appendf("; fasm x86_64 linux generated assembly using pl\n");
-        appendf("format ELF64\n");
-        appendf("section '.text' executable\n");
-
-        for (auto &op : ops)
-        {
-            GenerateOp(op);
-        }
-    }
-
-public:
-    // StackAllocator* m_stack = nullptr;
-    // TODO: handle sub-blocks
-    SlotAllocator *m_allocator = nullptr;
-};

include/codegen/slot.hpp

@@ -1,48 +0,0 @@
-#pragma once
-#include "prelude/string.hpp"
-
-namespace IR
-{
-
-struct IRSlot
-{
-    enum class Type
-    {
-        UNKNOWN = 0,
-        STACK,
-        REGISTRY,
-    };
-public:
-    IRSlot(StringView addr, unsigned int slot, Type slotType) : m_addr(addr), m_slot(slot), m_slotType(slotType) {}
-    IRSlot() = default;
-public:
-    Type GetType() const { return m_slotType; }
-    const StringView& GetAddr() const { return m_addr; }
-    unsigned int GetSlot() const { return m_slot; }
-public:
-    StringView Format() const {
-        StringBuilder sb;
-        switch(GetType())
-        {
-        case Type::REGISTRY:
-            sb << "r" << GetSlot();
-            break;
-        case Type::STACK:
-            sb << "s[" << GetSlot() << "]";
-            break;
-        default:
-            sb << "(UNKNOWN_SLOT_TYPE)";
-            break;
-        }
-        return sb.view();
-    }
-private:
-    StringView m_addr;
-    unsigned int m_slot;
-    Type m_slotType;
-};
-
-using IRSlotBuilder = Builder<IRSlot>;
-using IRSlotView = View<IRSlot>;
-
-} // namespace IR

include/codegen/targets/fasm_x86_64_linux.hpp

@@ -0,0 +1,247 @@
+#pragma once
+#include "codegen/codegen.hpp"
+#include "ir/op.hpp"
+#include "ir/ops.hpp"
+#include "ir/value.hpp"
+#include "prelude/linkedlist.hpp"
+#include "prelude/string.hpp"
+#include <unordered_map>
+
+class FasmX86_64Generator : public CodeGenerator
+{
+public:
+    FasmX86_64Generator() = default;
+
+public:
+    bool Generate(const DoubleLinkedList<IR::Op*>* ops) override
+    {
+        m_ops = ops;
+
+        output().Extend("format ELF64\n");
+        output().Extend("section '.text' executable\n");
+
+        for (m_current = m_ops->Begin(); m_current != nullptr; node_next())
+        {
+            GenerateStatement();
+        }
+
+        return true;
+    }
+
+private:
+    void GenerateExtern()
+    {
+        auto extrn = current<IR::ExternOp>();
+        // TODO: instead of __<symbol, use some random UID or hash string
+        // for safety and collision considerations
+        output().AppendFormat("extrn '%s' as __%s\n", extrn->symbol().c_str(), extrn->symbol().c_str());
+        output().AppendFormat("%s = PLT __%s\n", extrn->symbol().c_str(), extrn->symbol().c_str());
+    }
+
+    void GenerateFunction()
+    {
+        auto fn = current<IR::FnOp>();
+
+        m_slots.clear();
+        m_stackCounter = 0;
+
+        output().AppendFormat("public %s\n", fn->name().c_str());
+        output().AppendFormat("%s:\n", fn->name().c_str());
+        output().Extend("  push rbp\n");
+        output().Extend("  mov rbp, rsp\n");
+
+        auto fnNode = node<IR::Op>();
+        auto ops = m_ops;
+        m_ops = &fn->body().ops();
+        for (m_current = m_ops->Begin(); m_current != nullptr; node_next())
+        {
+            GenerateStatement();
+        }
+        m_ops = ops;
+        m_current = fnNode;
+
+        output().Extend("  leave\n");
+        output().Extend("  ret\n");
+    }
+
+    void GenerateCall()
+    {
+        auto call = current<IR::CallOp>();
+        // TODO: support stack spilled arguments
+        assert(call->args().size < 7 && "stack arguments not supported yet");
+        const char *regs[6] = {"edi", "esi", "edx", "ecx","e8", "e9"};
+        for (size_t i = 0; i < call->args().size; ++i)
+        {
+            auto arg = call->args().data[i];
+            if (arg->HasId()) {
+                auto sp = EnsureSlot(arg);
+                // TODO:
+                auto size = "dword";
+                output().AppendFormat("  mov %s, %s [rbp-%d]\n", regs[i], size, sp);
+            } else {
+                output().AppendFormat("  mov %s, %d\n", regs[i], reinterpret_cast<IR::ConstantInt*>(arg)->GetValue());
+            }
+        }
+        output().AppendFormat("  call %s\n", call->callee().c_str());
+        auto sp = EnsureSlot(call->result());
+        auto size = "dword";
+        output().AppendFormat("  mov %s [rbp-%d], eax\n", size, sp);
+    }
+
+    void GenerateAllocate()
+    {
+        auto totalAllocSize = 0;
+        while (current<IR::Op>()->GetType() == IR::OpType::ALLOCATE)
+        {
+            auto alloc = current<IR::AllocateOp>();
+            // TODO: support other types
+            assert(alloc->Type()->kind == IR::ValueHandle::Type::Kind::Int);
+            // TODO: dynamic size + alignment
+            auto allocSize = 4;
+            totalAllocSize += allocSize;
+            m_stackCounter += allocSize;
+            m_slots.insert(std::make_pair(alloc->result()->GetId(), m_stackCounter));
+
+            if (seek<IR::Op>() && seek<IR::Op>()->get()->GetType() == IR::OpType::ALLOCATE) node_next();
+            else break;
+        };
+        output().AppendFormat("  sub rsp, %d\n", totalAllocSize);
+    }
+
+    void GenerateStore()
+    {
+        auto store = current<IR::StoreOp>();
+        auto sp = EnsureSlot(store->dst());
+
+        // TODO: support other types
+        assert(store->src()->GetType()->kind == IR::ValueHandle::Type::Kind::Int);
+        if (!store->src()->HasId()) {
+            auto value = reinterpret_cast<const IR::ConstantInt*>(store->src());
+            auto size = "dword";
+            output().AppendFormat("  mov %s [rbp-%d], %d\n", size, sp, value->GetValue());
+        } else {
+            auto ssp = EnsureSlot(store->src());
+            auto size = "dword";
+            output().AppendFormat("  mov eax, %s [rbp-%d]\n", size, ssp);
+            output().AppendFormat("  mov %s [rbp-%d], eax\n", size, sp);
+        }
+    }
+
+    void GenerateLoad()
+    {
+        auto load = current<IR::LoadOp>();
+        auto sp = EnsureSlot(load->Ptr());
+
+        // TODO: support other types
+        auto size = "dword";
+        output().AppendFormat("  mov eax, %s [rbp-%d]\n", size, sp);
+
+        sp = EnsureSlot(load->result());
+        output().AppendFormat("  mov dword [rbp-%d], eax\n", sp);
+    }
+
+    void GenerateMath()
+    {
+        auto math = current<IR::MathOp>();
+        StringBuilder sb;
+
+        switch(math->GetType())
+        {
+        case IR::OpType::ADD:
+            sb << "add";
+            break;
+        case IR::OpType::SUB:
+            sb << "sub";
+            break;
+        case IR::OpType::MUL:
+            sb << "imul";
+            break;
+        case IR::OpType::DIV:
+            sb << "div";
+            break;
+        default: assert(false && "unreachable or not implemented");
+        }
+
+        auto op = sb.view();
+
+        // TODO:
+        auto size = "dword";
+        if (!math->lhs()->HasId()) {
+            output().AppendFormat("  mov eax, %d\n", reinterpret_cast<IR::ConstantInt*>(math->lhs())->GetValue());
+        } else {
+            auto lsp = EnsureSlot(math->lhs());
+            output().AppendFormat("  mov eax, %s [rbp-%d]\n", size, lsp);
+        }
+        if (!math->rhs()->HasId()) {
+            output().AppendFormat("  %s eax, %d\n", op.c_str(), reinterpret_cast<IR::ConstantInt*>(math->rhs())->GetValue());
+        } else {
+            auto lsp = EnsureSlot(math->rhs());
+            output().AppendFormat("  %s eax, %s [rbp-%d]\n", op.c_str(), size, lsp);
+        }
+
+        auto sp = EnsureSlot(math->result());
+        output().AppendFormat("  mov %s [rbp-%d], eax\n", size, sp);
+    }
+
+    void GenerateStatement()
+    {
+        auto op = current<IR::Op>();
+        switch(op->GetType())
+        {
+        case IR::OpType::EXTERN:
+            return GenerateExtern();
+        case IR::OpType::FN:
+            return GenerateFunction();
+        case IR::OpType::CALL:
+            return GenerateCall();
+        case IR::OpType::ALLOCATE:
+            return GenerateAllocate();
+        case IR::OpType::STORE:
+            return GenerateStore();
+        case IR::OpType::LOAD:
+            return GenerateLoad();
+        case IR::OpType::ADD:
+        case IR::OpType::SUB:
+        case IR::OpType::MUL:
+        case IR::OpType::DIV:
+            return GenerateMath();
+        // TODO:
+        default: output().AppendFormat("  ; %d not implemented\n", op->GetType());
+        }
+    }
+
+private:
+    uint32_t EnsureSlot(const IR::ValueHandle* value)
+    {
+        assert(value->HasId());
+        auto stackPointer = m_slots.find(value->GetId());
+        if (stackPointer != m_slots.end())
+        {
+            return stackPointer->second;
+        }
+
+        // TODO: dynamic size based on type
+        auto allocSize = 4;
+        output().AppendFormat("  sub rsp, %d\n", allocSize);
+        m_stackCounter += allocSize;
+        m_slots.insert(std::make_pair(value->GetId(), m_stackCounter));
+        return m_stackCounter;
+    }
+
+private:
+    template<typename T>
+    ListNode<T*>* node() { return reinterpret_cast<ListNode<T*>*>(m_current); }
+    template<typename T>
+    ListNode<T*>* seek() { return m_current && m_current->next ? reinterpret_cast<ListNode<T*>*>(m_current->next) : nullptr; }
+
+    void node_next() { assert(m_current); m_current = m_current->next; }
+
+    template<typename T>
+    T* current() const { return reinterpret_cast<T*>(m_current->value); }
+
+private:
+    const DoubleLinkedList<IR::Op*>* m_ops;
+    ListNode<IR::Op*>* m_current;
+    std::unordered_map<uint32_t, uint32_t> m_slots;
+    uint32_t m_stackCounter = 0;
+};

include/ir/block.hpp

@@ -10,8 +10,8 @@ using BlockID = unsigned int;
 class Block
 {
 public:
-    Block(BlockID id, const OpView& ops)
+    Block(BlockID id, DoubleLinkedList<Op*> ops)
-        : m_id(id), m_ops(DoubleLinkedList<Op*>::FromView(ops)) {}
+        : m_id(id), m_ops(ops) {}
 public:
     DoubleLinkedList<Op*>& ops() { return m_ops; }
 public:

include/ir/ir.hpp

@@ -2,6 +2,7 @@
 #include <unordered_map>
 #include "parser/nodes.hpp"
 #include "prelude/error.hpp"
+#include "prelude/linkedlist.hpp"
 #include "prelude/string.hpp"
 #include "ir/value.hpp"
 #include "ir/ops.hpp"
@@ -13,7 +14,7 @@ namespace IR
     {
     public:
         IRBuilder(const StringView &filename, const Node *root)
-            : m_root(root), m_ops(new OpBuilder()), m_filename(filename) {}
+            : m_root(root), m_ops(new DoubleLinkedList<Op*>), m_filename(filename) {}
 
     public:
         // TODO: support other literals
@@ -28,8 +29,8 @@ namespace IR
             auto value = ParseExpression(varDecl->value());
             // TODO: gather type information from var decl signature, aka local <int> v = 0;
             auto dst = AllocateNamed<Pointer>(value->GetType());
-            m_ops->Push(new AllocateOp(dst, value->GetType()));
+            m_ops->Append(m_ops->New(new AllocateOp(dst, value->GetType())));
-            m_ops->Push(new StoreOp(value, reinterpret_cast<Pointer *>(dst)));
+            m_ops->Append(m_ops->New(new StoreOp(value, reinterpret_cast<Pointer *>(dst))));
             m_locals.insert(std::make_pair(varDecl->name(), reinterpret_cast<Pointer *>(dst)));
         }
 
@@ -42,22 +43,21 @@ namespace IR
                 assert(false);
             }
             auto dst = AllocateNamed<Instruction>(m_locals[var->name()]->GetValueType());
-            m_ops->Push(new LoadOp(dst, m_locals[var->name()]));
+            m_ops->Append(m_ops->New(new LoadOp(dst, m_locals[var->name()])));
             return reinterpret_cast<ValueHandle *>(dst);
         }
 
         ValueHandle *ParseFnCall(const FnCallNode *fn)
         {
-            // TODO: support multiple args
+            auto args = ValueBuilder();
-            auto argRegs = ValueBuilder();
+            for (size_t i = 0; i < fn->args().size; ++i)
-            if (fn->arg() != nullptr)
             {
-                auto arg = ParseExpression(fn->arg());
+                auto arg = ParseExpression(fn->args().data[i]);
-                argRegs.Push(arg);
+                args.Push(arg);
             }
             // TODO: gather return type of the function
-            auto dst = AllocateNamed<Instruction>(new ValueHandle::Type {ValueHandle::Type::Kind::Void});
+            auto dst = AllocateNamed<Instruction>(new ValueHandle::Type {ValueHandle::Type::Kind::Int});
-            m_ops->Push(new CallOp(dst, fn->name(), argRegs.view()));
+            m_ops->Append(m_ops->New(new CallOp(dst, fn->name(), args.view())));
             return dst;
         }
 
@@ -93,16 +93,16 @@ namespace IR
                 switch (expr->op())
                 {
                 case ExpressionNode::Operator::Plus:
-                    m_ops->Push(new MathOp(dst, lhs, rhs, OpType::ADD));
+                    m_ops->Append(m_ops->New(new MathOp(dst, lhs, rhs, OpType::ADD)));
                     break;
                 case ExpressionNode::Operator::Multiply:
-                    m_ops->Push(new MathOp(dst, lhs, rhs, OpType::MUL));
+                    m_ops->Append(m_ops->New(new MathOp(dst, lhs, rhs, OpType::MUL)));
                     break;
                 case ExpressionNode::Operator::Minus:
-                    m_ops->Push(new MathOp(dst, lhs, rhs, OpType::SUB));
+                    m_ops->Append(m_ops->New(new MathOp(dst, lhs, rhs, OpType::SUB)));
                     break;
                 case ExpressionNode::Operator::Divide:
-                    m_ops->Push(new MathOp(dst, lhs, rhs, OpType::DIV));
+                    m_ops->Append(m_ops->New(new MathOp(dst, lhs, rhs, OpType::DIV)));
                     break;
                 default:
                     assert(0 && "unreachable");
@@ -131,12 +131,12 @@ namespace IR
                 }
             }
             auto ops = EndBlock();
-            auto block = Block(m_block_counter++, std::move(ops->view()));
+            auto block = Block(m_block_counter++, *ops);
             operator delete(ops);
             return block;
         }
 
-        OpView Build()
+        DoubleLinkedList<Op*>* Build()
         {
             assert(m_root->GetType() == NodeType::Program && "root should be a program");
             auto program = reinterpret_cast<const ProgramNode *>(m_root);
@@ -144,30 +144,30 @@ namespace IR
             // Externs
             for (auto &extrn : program->externs())
             {
-                m_ops->Push(new ExternOp(extrn->symbol()));
+                m_ops->Append(m_ops->New(new ExternOp(extrn->symbol())));
             }
 
             // Functions
             for (auto &fn : program->funcs())
             {
                 auto block = ParseBlock(fn->body());
-                m_ops->Push(new FnOp(fn->name(), fn->params(), std::move(block)));
+                m_ops->Append(m_ops->New(new FnOp(fn->name(), fn->params(), std::move(block))));
             }
 
-            return OpView(m_ops->data, m_ops->size);
+            return m_ops;
         }
 
     public:
-        OpView ops() const { return OpView(m_ops->data, m_ops->size); }
+        const DoubleLinkedList<Op*>* ops() const { return m_ops; }
 
     private:
         void StartBlock()
         {
             m_containers.Push(m_ops);
-            m_ops = new OpBuilder();
+            m_ops = new DoubleLinkedList<Op*>;
         }
 
-        OpBuilder *EndBlock()
+        DoubleLinkedList<Op*> *EndBlock()
         {
             assert(m_containers.size > 0 && "containers stack is empty");
             auto current = m_ops;
@@ -193,13 +193,13 @@ namespace IR
         const Node *m_root = nullptr;
         StringView m_filename;
 
-        OpBuilder *m_ops = nullptr;
+        DoubleLinkedList<Op*> *m_ops = nullptr;
         unsigned int m_value_counter = 0;
         unsigned int m_block_counter = 0;
 
         std::unordered_map<StringView, Pointer *> m_locals;
 
-        Builder<OpBuilder *> m_containers;
+        Builder<DoubleLinkedList<Op*>*> m_containers;
     };
 
 } // namespace IR

include/ir/ops.hpp

@@ -82,6 +82,9 @@ namespace IR
             return sb.view();
         }
 
+    public:
+        const ValueHandle::Type *Type() const { return m_typ; }
+
     private:
         ValueHandle::Type *m_typ;
     };
@@ -103,6 +106,9 @@ namespace IR
             return sb.view();
         }
 
+    public:
+        const Pointer* Ptr() const { return m_ptr; }
+
     private:
         Pointer* m_ptr;
     };

include/parser/ast.hpp

@@ -45,14 +45,15 @@ public:
         // m_lexer->NextExpect(TokenType::Id);
         // char* name = strdup(m_lexer->token().string);
         m_lexer->NextExpect('(');
-        Node* arg = nullptr;
+        Builder<Node*> args;
-        // TODO: support multiple arguments
+        while (m_lexer->seek_token()->token != ')')
-        if (m_lexer->seek_token()->token != ')')
         {
-            arg = ParseExpression();
+            auto arg = ParseExpression();
+            args.Push(arg);
+            if (m_lexer->seek_token()->token == ',') assert(m_lexer->NextToken());
         }
         m_lexer->NextExpect(')');
-        return new FnCallNode(name, arg);
+        return new FnCallNode(name, std::move(args.view()));
     }
 
     Node* ParseFactor()
@@ -80,7 +81,7 @@ public:
         }
         default:
             // fprintf(stderr, "%s:%d:%d: ERROR: unexpected token while parsing %ld\n", m_lexer->filename(), token->line_number, token->offset_start, token->token);
-            ErrorLogger::Raise(Error::ParseError(m_lexer->filename(), StringView::FromFormat("unexpected token while parsing '%c'", token->token), token->line_number, token->offset_start));
+            ErrorLogger::Raise(Error::ParseError(m_lexer->filename(), StringView::FromFormat("unexpected token while parsing '%d'", token->token), token->line_number, token->offset_start));
             break;
         }
 
@@ -179,7 +180,7 @@ public:
             case TokenType::Fn: program->PushFunction(ParseFnDecl()); break;
             case TokenType::Extern: program->PushExtern(ParseExtern()); break;
             default: {
-                ErrorLogger::Raise(Error::ParseError(m_lexer->filename(), StringView::FromFormat("unexpected token while parsing '%c'", token.token), token.line_number, token.offset_start));
+                ErrorLogger::Raise(Error::ParseError(m_lexer->filename(), StringView::FromFormat("unexpected token while parsing '%d'", token.token), token.line_number, token.offset_start));
                 assert(false);
             }
             break;

include/parser/lexer.hpp

@@ -47,13 +47,13 @@ inline bool operator!=(char c, TokenType t)
 
 struct Token
 {
-    TokenType token;
+    TokenType token = TokenType::Unknown;
-    long int_number;
+    long int_number = 0;
     // null-terminated
     StringView string;
-    long line_number;
+    long line_number = 0;
-    long offset_start;
+    long offset_start = 0;
-    long offset_end;
+    long offset_end = 0;
 public:
     Token(TokenType t) : token(t) {}
     Token(TokenType t, long lnumber, long soffset, long eoffset)
@@ -73,7 +73,7 @@ public:
         auto lnl = m_last_newline;
         if (!NextToken())
         {
-            return nullptr;
+            return new Token(TokenType::Eof, m_line, m_pos - m_last_newline, m_pos - m_last_newline);
         }
         auto seeked = m_token;
         m_token = s;
@@ -92,72 +92,98 @@ public:
 public:
     bool NextToken()
     {
-        // if (m_pos >= m_code.len())
+        auto len = m_code.len();
-        // {
-        //     m_token = Token(TokenType::Eof);
-        //     return false;
-        // }
 
-        char c = m_code.data[m_pos++];
+        auto peek = [&]() -> char {
+            return (m_pos < len) ? m_code.data[m_pos] : '\0';
+        };
 
-        while(std::isspace(c)) {
+        auto advance = [&]() -> char {
-            if (c == '\n')
+            return (m_pos < len) ? m_code.data[m_pos++] : '\0';
-            {
+        };
-                m_line++;
-                m_last_newline = m_pos;
-            }
-            c = m_code.data[m_pos++];
-        }
 
-        if (m_pos >= m_code.len())
+        // IMPORTANT: >= not >
+        if (m_pos >= len)
         {
             m_token = Token(TokenType::Eof);
             return false;
         }
 
-        if (std::isalpha(c) != 0 || c == '_')
+        char c = advance();
+
+        // skip whitespace safely
+        while (c != '\0' && std::isspace((unsigned char)c))
+        {
+            if (c == '\n')
+            {
+                m_line++;
+                m_last_newline = m_pos;
+            }
+
+            if (m_pos >= len) // reached real EOF while skipping whitespace
+            {
+                m_token = Token(TokenType::Eof);
+                return false;
+            }
+
+            c = advance();
+        }
+
+        if (c == '\0' || m_pos > len) // paranoia guard
+        {
+            m_token = Token(TokenType::Eof);
+            return false;
+        }
+
+        // identifier
+        if (std::isalpha((unsigned char)c) || c == '_')
         {
             StringBuilder s;
-            long offset_start = m_pos - m_last_newline;
+            long offset_start = m_pos - m_last_newline - 1; // -1 because we already consumed c
             s.Push(c);
-            // id
+
-            while (std::isalpha(m_code.data[m_pos]) != 0 || m_code.data[m_pos] == '_')
+            // NOTE: usually identifiers allow digits after first char; add isdigit if you want
+            while (true)
             {
-                s.Push(m_code.data[m_pos++]);
+                char p = peek();
+                if (!(std::isalpha((unsigned char)p) || p == '_'))
+                    break;
+                s.Push(advance());
             }
+
             s.Push('\0');
             m_token = Token(TokenType::Id, m_line, offset_start, m_pos - m_last_newline);
             m_token.string = s.view();
 
-            if (strcmp("extern", m_token.string.c_str()) == 0)
+            if (strcmp("extern", m_token.string.c_str()) == 0) m_token.token = TokenType::Extern;
-            {
+            else if (strcmp("fn", m_token.string.c_str()) == 0) m_token.token = TokenType::Fn;
-                m_token.token = TokenType::Extern;
+            else if (strcmp("local", m_token.string.c_str()) == 0) m_token.token = TokenType::Local;
-            }
-
-            if (strcmp("fn", m_token.string.c_str()) == 0)
-            {
-                m_token.token = TokenType::Fn;
-            }
-
-            if (strcmp("local", m_token.string.c_str()) == 0)
-            {
-                m_token.token = TokenType::Local;
-            }
 
             return true;
         }
 
-        if (std::isdigit(c) != 0)
+        // integer (hex supported)
+        if (std::isdigit((unsigned char)c))
         {
             StringBuilder s;
-            long offset_start = m_pos - m_last_newline;
+            long offset_start = m_pos - m_last_newline - 1;
-            bool hex = c == '0' && m_code.data[m_pos] == 'x';
+
+            bool hex = (c == '0' && peek() == 'x');
             s.Push(c);
-            // integer (could be hex)
+
-            while (std::isdigit(m_code.data[m_pos]) != 0 || (hex && std::isalpha(m_code.data[m_pos]) != 0))
+            if (hex) s.Push(advance()); // consume 'x'
+
+            while (true)
             {
-                s.Push(m_code.data[m_pos++]);
+                char p = peek();
+                if (std::isdigit((unsigned char)p) ||
+                    (hex && std::isxdigit((unsigned char)p)))
+                {
+                    s.Push(advance());
+                }
+                else break;
             }
+
             s.Push('\0');
             m_token = Token(TokenType::IntLiteral, m_line, offset_start, m_pos - m_last_newline);
             m_token.int_number = std::strtol(s.data, nullptr, hex ? 16 : 10);
@@ -165,7 +191,8 @@ public:
             return true;
         }
 
-        m_token = Token((TokenType)c, m_line, m_pos - m_last_newline, m_pos - m_last_newline + 1);
+        // single-char token fallback
+        m_token = Token((TokenType)c, m_line, m_pos - m_last_newline - 1, m_pos - m_last_newline);
         return true;
     }
 

include/parser/nodes.hpp

@@ -144,20 +144,17 @@ class FnCallNode : public Node
 {
 public:
     // TODO: support multiple arguments
-    FnCallNode(const StringView& name, Node* arg)
+    FnCallNode(const StringView& name, View<Node*>&& arg)
-        : m_name(name), m_arg(arg) {}
+        : m_name(name), m_args(arg) {}
-    ~FnCallNode() override {
+    ~FnCallNode() override = default;
-        delete m_arg;
-    }
 
     NODE_TYPE(FnCall)
 public:
     const StringView& name() const { return m_name; }
-    // TODO: support multiple args
+    const View<Node*>& args() const { return m_args; }
-    const Node* arg() const { return m_arg; }
 private:
     StringView m_name;
-    Node* m_arg;
+    View<Node*> m_args;
 };
 
 class VariableNode : public Node

include/prelude/linkedlist.hpp

@@ -8,12 +8,16 @@ struct ListNode
     T value;
     ListNode* prev = nullptr;
     ListNode* next = nullptr;
+public:
+    T& get() noexcept { return value; }
+    const T& get() const noexcept { return value; }
 };
 
 template<typename T>
 class DoubleLinkedList {
 public:
     DoubleLinkedList() = default;
+    ~DoubleLinkedList() = default;
 
 public:
     static DoubleLinkedList<T> FromView(const View<T> &view)
@@ -26,7 +30,6 @@ public:
         return list;
     }
 
-public:
     View<T> ToView()
     {
         Builder<T> b;
@@ -37,6 +40,9 @@ public:
         return b.view();
     }
 
+public:
+    ListNode<T>* New(T value) const { return new ListNode<T>(value); }
+
 public:
     void Append(ListNode<T>* node)
     {

src/main.cpp

@@ -2,6 +2,7 @@
 #include <cstdio>
 #include <cstdlib>
 #include <print>
+#include "codegen/targets/fasm_x86_64_linux.hpp"
 #include "ir/op.hpp"
 #include "ir/optimize.hpp"
 #include "parser/lexer.hpp"
@@ -60,9 +61,9 @@ int main(int argc, char **argv)
 
     auto ops = irBuilder.Build();
 
-    for (size_t i = 0; i < ops.size; ++i)
+    for (auto cur = ops->Begin(); cur != nullptr; cur = cur->next)
     {
-        auto op = ops.data[i];
+        auto op = cur->value;
         if (op->GetType() == IR::OpType::FN)
         {
             auto fn = reinterpret_cast<IR::FnOp*>(op);
@@ -72,35 +73,22 @@ int main(int argc, char **argv)
         }
     }
 
-    StringBuilder sb;
+    for (auto cur = ops->Begin(); cur != nullptr; cur = cur->next)
-    for (size_t i = 0; i < ops.size; ++i)
     {
-        sb.AppendFormat("%s\n", ops.data[i]->Format(0).c_str());
+        auto op = cur->value;
+        printf("%s\n", op->Format(0).c_str());
     }
 
-    printf("%s\n", sb.c_str());
+    FasmX86_64Generator gen;
 
-    auto output = File::Open("example.ll", File::Mode::WRITE);
+    gen.Generate(ops);
-    if (!output.Write(sb.view()))
+
+    auto output = File::Open("example.asm", File::Mode::WRITE);
+    if (!output.Write(gen.GetOutput()))
     {
         fprintf(stderr, "ERROR: Failed to write IR to a file");
     }
     std::println("OK");
 
-    // StackFasmX86_64Generator gen;
-
-    // gen.Generate(filename, ops);
-
-    // StringView output = gen.GetOutput();
-
-    // FILE *file = fopen("out.asm", "w");
-
-    // fwrite(output.c_str(), output.size, sizeof(char), file);
-
-    // fclose(file);
-
-    // system("fasm out.asm");
-    // system("gcc -o out out.o");
-
     return 0;
 }