Files
pl/include/codegen.hpp

292 lines
8.5 KiB
C++

// 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 "string.hpp"
#include "ir.hpp"
template<typename Slot>
class Allocator
{
public:
virtual ~Allocator() {};
public:
virtual const Slot& Allocate(const StringView& addr) = 0;
virtual const Slot& Resolve(const StringView& addr) = 0;
};
struct StackSlot
{
size_t offset;
StringView addr;
};
class StackAllocator : public Allocator<StackSlot>
{
public:
StackAllocator() = default;
~StackAllocator() override = default;
public:
const StackSlot& Allocate(const StringView& addr)
{
m_offset_counter += 4;
m_slots.Push(StackSlot { m_offset_counter, addr });
return m_slots.data[m_slots.size - 1];
}
const StackSlot& Resolve(const StringView& addr)
{
for (size_t i = 0; i < m_slots.size; ++i)
{
if (strcmp(m_slots.data[i].addr.c_str(), addr.c_str()) == 0)
{
return m_slots.data[i];
}
}
assert(0 && "could not resolve stack offset for specified address");
}
private:
size_t m_offset_counter = 0;
Builder<StackSlot> m_slots;
};
// struct ConstSlot
// {
// long value;
// StringView addr;
// };
// class ConstAllocator : public Allocator<ConstSlot>
// {
// public:
// ConstAllocator() = default;
// ~ConstAllocator() override = default;
// public:
// const ConstSlot& Allocate(const StringView& addr)
// {
// m_slots.Push(ConstSlot { 0, addr });
// return m_slots.data[m_slots.size - 1];
// }
// const ConstSlot& StoreValue(const StringView& addr, long value)
// {
// for (size_t i = 0; i < m_slots.size; ++i)
// {
// if (strcmp(m_slots.data[i].addr.c_str(), addr.c_str()) == 0)
// {
// m_slots.data[i].value = value;
// return m_slots.data[i];
// }
// }
// assert(0 && "could not resolve const under specified address");
// }
// const ConstSlot& Resolve(const StringView& addr)
// {
// for (size_t i = 0; i < m_slots.size; ++i)
// {
// if (strcmp(m_slots.data[i].addr.c_str(), addr.c_str()) == 0)
// {
// return m_slots.data[i];
// }
// }
// assert(0 && "could not resolve const under specified address");
// }
// private:
// Builder<ConstSlot> m_slots;
// };
// struct RegisterSlot
// {
// const StringView& reg;
// StringView addr;
// };
// class RegisterAllocator : public Allocator<RegisterSlot>
// {
// public:
// RegisterAllocator()
// {
// m_regs.Push(std::move(StringView("eax")));
// m_regs.Push(std::move(StringView("ecx")));
// }
// ~RegisterAllocator() override = default;
// public:
// const RegisterSlot& Allocate(const StringView& addr)
// {
// assert(m_slots.size < m_regs.size && "no space available for allocating to register");
// m_slots.Push(RegisterSlot { m_regs.data[m_slots.size], addr });
// return m_slots.data[m_slots.size - 1];
// }
// const RegisterSlot& Resolve(const StringView& addr)
// {
// for (size_t i = 0; i < m_slots.size; ++i)
// {
// if (strcmp(m_slots.data[i].addr.c_str(), addr.c_str()) == 0)
// {
// return m_slots.data[i];
// }
// }
// assert(0 && "could not resolve register for specified address");
// }
// void Clear()
// {
// m_slots.size = 0;
// }
// private:
// Builder<RegisterSlot> m_slots;
// Builder<StringView> m_regs;
// };
class CodeGenerator
{
public:
virtual ~CodeGenerator() {};
virtual void Generate(const char* filename, View<IR::Op*> ops) = 0;
};
class StackFasmX86_64Generator : public CodeGenerator
{
public:
~StackFasmX86_64Generator() override = default;
private:
int GetStackSize(const IR::OpView ops)
{
int stackSize = 0;
for (auto &op : ops)
{
switch (op->GetType())
{
case IR::OpType::STORE:
case IR::OpType::LOAD:
case IR::OpType::LOAD_CONST:
case IR::OpType::ADD:
case IR::OpType::CALL:
stackSize += 4;
}
}
return stackSize;
}
StringView GetTempAddr(IR::Reg reg)
{
return std::move((StringBuilder() << 't' << reg).view());
}
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();
printf("extrn '%s' as __%s\n", symbol.c_str(), symbol.c_str());
printf("%s = PLT __%s\n", symbol.c_str(), symbol.c_str());
}
break;
case IR::OpType::FN:
{
auto fn = reinterpret_cast<const IR::FnOp *>(op);
auto name = fn->name();
printf("public %s\n", name.c_str());
printf("%s:\n", name.c_str());
printf("push rbp\n");
printf("mov rbp, rsp\n");
m_stack = new StackAllocator();
int stackSize = GetStackSize(fn->ops());
printf("sub rsp, %d\n", stackSize);
if (fn->params().size > 0)
{
auto param_slot = m_stack->Allocate(fn->params().data[0]);
printf("mov [rbp-%d], edi\n", param_slot.offset);
}
for(auto &fOp : fn->ops())
{
GenerateOp(fOp);
}
m_stack = nullptr;
printf("leave\nret\n");
}
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_stack->Resolve(GetTempAddr(call->args().data[0]));
printf("mov edi, [rbp-%d]\n", slot.offset);
}
printf("call %s\n", call->callee().c_str());
auto result_slot = m_stack->Allocate(GetTempAddr(call->result()));
printf("mov dword [rbp-%d], eax\n", result_slot.offset);
}
break;
case IR::OpType::LOAD_CONST:
{
auto lc = reinterpret_cast<const IR::LoadConstOp *>(op);
auto addr = GetTempAddr(lc->result());
auto slot = m_stack->Allocate(addr);
printf("mov dword [rbp-%d], %ld\n", slot.offset, lc->value());
}
break;
case IR::OpType::STORE:
{
auto s = reinterpret_cast<const IR::StoreOp *>(op);
printf("; DEBUG: resolving stack slot at %s\n", s->addr().c_str());
auto slot = m_stack->Allocate(s->addr());
auto value_slot = m_stack->Resolve(GetTempAddr(s->src()));
printf("mov eax, [rbp-%d]\n", value_slot.offset);
printf("mov dword [rbp-%d], eax\n", slot.offset);
}
break;
case IR::OpType::LOAD:
{
auto l = reinterpret_cast<const IR::LoadOp *>(op);
auto value_slot = m_stack->Allocate(GetTempAddr(l->result()));
auto variable_slot = m_stack->Resolve(l->addr());
printf("mov eax, [rbp-%d]\n", variable_slot.offset);
printf("mov dword [rbp-%d], eax\n", value_slot.offset);
}
break;
case IR::OpType::ADD:
{
auto expr = reinterpret_cast<const IR::AddOp *>(op);
auto lhs_slot = m_stack->Resolve(GetTempAddr(expr->lhs()));
printf("mov eax, [rbp-%d]\n", lhs_slot.offset);
auto rhs_slot = m_stack->Resolve(GetTempAddr(expr->rhs()));
printf("add eax, [rbp-%d]\n", rhs_slot.offset);
auto result_slot = m_stack->Allocate(GetTempAddr(expr->result()));
printf("mov dword [rbp-%d], eax\n", result_slot.offset);
}
break;
default: printf("; NOT HANDLED\n; %s\n", op->Format(0).c_str()); break;
}
}
public:
void Generate(const char* filename, View<IR::Op*> ops) override
{
printf("; fasm x86_64 linux generated assembly using pl\n");
printf("format ELF64\n");
printf("section '.text' executable\n");
for (auto& op : ops)
{
GenerateOp(op);
}
}
public:
// TODO: handle sub-blocks
StackAllocator* m_stack = nullptr;
};