alduin 0.0.1

WIP: A toy compiler backend
Documentation
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use std::collections::HashMap;
use std::sync::Arc;

use crate::backend::Reg;
use crate::compiler::compiled_code::{CallSite, CompiledCode, Symbol};
use crate::compiler::graph::cfg::liveness::LiveIntervalValueCategory;
use crate::compiler::graph::cfg::CFG;
use crate::compiler::graph::{Const, Literal, NodeId, Type};
use crate::compiler::Compiler;
use dynasmrt::x64::X64Relocation;
use dynasmrt::VecAssembler;
use dynasmrt::{dynasm, DynamicLabel, DynasmApi, DynasmLabelApi};

use super::call_sites::X64StaticCallSite;
use super::compiled_code::X64CompiledCode;
use super::{X64Reg, X64};

type Op = crate::compiler::graph::BaseOp;

const TMP0: u8 = X64Reg::R14 as usize as u8;
const TMP1: u8 = X64Reg::R15 as usize as u8;

pub struct CodeGen<'c, 'cfg> {
    compiler: &'c Compiler,
    symbol: Symbol,
    cfg: &'cfg mut CFG<Op>,
    ops: VecAssembler<X64Relocation>,
    labels: Vec<DynamicLabel>,
    current_block_id: usize,
    static_call_sites: HashMap<usize, Box<X64StaticCallSite>>,
    rsp_delta: i32,
    extra_push: bool,
    constants: HashMap<Const, DynamicLabel>,
}

impl<'c, 'cfg> CodeGen<'c, 'cfg> {
    pub fn new(compiler: &'c Compiler, symbol: Symbol, cfg: &'cfg mut CFG<Op>) -> Self {
        Self {
            compiler,
            symbol,
            cfg,
            ops: VecAssembler::new(0),
            labels: vec![],
            current_block_id: 0,
            static_call_sites: Default::default(),
            rsp_delta: 0,
            extra_push: false,
            constants: Default::default(),
        }
    }

    fn register_constant(&mut self, constant: Const) -> DynamicLabel {
        if self.constants.contains_key(&constant) {
            self.constants[&constant]
        } else {
            let label = self.ops.new_dynamic_label();
            self.constants.insert(constant, label);
            label
        }
    }

    fn record_static_callsite(&mut self, symbol: Symbol, return_address_offset: usize) {
        self.static_call_sites.insert(
            return_address_offset,
            Box::new(X64StaticCallSite::new(symbol, return_address_offset)),
        );
    }

    fn gen_prologue(&mut self) {
        dynasm! {self.ops
            ; push rbp
            ; mov rbp, rsp
        }
        let mut rsp_offset = 8usize;
        // Spill callee saved registers
        let mut num_callee_saved_regs = 0;
        for r in self.cfg.used_registers.iter_ones() {
            let r: X64Reg = r.into();
            if r.is_callee_saved() {
                assert!(!r.is_fpr());
                num_callee_saved_regs += 1;
                dynasm!(self.ops; push Rq(r as u8));
                rsp_offset += 8;
            }
        }
        // Reserve space for intervals, and fix RSP alignment
        self.rsp_delta = self.cfg.stack_size as i32;
        if (num_callee_saved_regs & 1) != 0 {
            self.rsp_delta += 8;
        }
        if self.rsp_delta != 0 {
            dynasm!(self.ops; sub rsp, self.rsp_delta);
            rsp_offset += self.rsp_delta as usize;
        }
        assert_eq!((rsp_offset & 0b111), 0);
        if (rsp_offset & 0b1111) == 0 {
            dynasm!(self.ops; push rax);
            self.extra_push = true;
        }
    }

    fn gen_epilogue(&mut self) {
        // Clear previously reserverd space for intervals
        if self.extra_push {
            dynasm!(self.ops; pop rcx);
        }
        if self.rsp_delta != 0 {
            dynasm!(self.ops; add rsp, self.rsp_delta);
        }
        // Restore callee saved registers
        for r in self.cfg.used_registers.iter_ones().rev() {
            let r: X64Reg = r.into();
            if r.is_callee_saved() {
                assert!(!r.is_fpr());
                dynasm!(self.ops; pop Rq(r as u8));
            }
        }
        dynasm! {self.ops
            ; mov rsp, rbp
            ; pop rbp
            ; ret
        }
    }

    fn gen_mov_reg_reg(&mut self, t: Type, dst: u8, src: u8) {
        if dst == src {
            return;
        }
        match t {
            Type::Bool | Type::I8 => dynasm!(self.ops; mov Rb(dst), Rb(src)),
            Type::I16 => dynasm!(self.ops; mov Rw(dst), Rw(src)),
            Type::I32 => dynasm!(self.ops; mov Rd(dst), Rd(src)),
            Type::I64 => dynasm!(self.ops; mov Rq(dst), Rq(src)),
            Type::F32 => dynasm!(self.ops; movss Rx(dst), Rx(src)),
            Type::F64 => dynasm!(self.ops; movsd Rx(dst), Rx(src)),
            Type::Void | Type::Top => unreachable!(),
        }
    }

    fn gen_push(&mut self, n: NodeId, stack_arg_index: i32, total_stack_arg_size: i32) {
        let reg = if let Some(reg) = self.cfg.liveness[self.cfg.g[n].interval].reg {
            reg as u8
        } else {
            let mem = self.cfg.liveness[self.cfg.g[n].interval].mem;
            self.gen_mov_reg_stack(self.cfg.g[n].ty, TMP0, mem);
            TMP0
        };
        let offset = -total_stack_arg_size + (stack_arg_index << 3);
        match self.cfg.g[n].ty {
            Type::Bool | Type::I8 | Type::I16 | Type::I32 | Type::I64 => {
                dynasm!(self.ops; mov [rsp + offset], Rq(reg))
            }
            Type::F32 => {
                dynasm!(self.ops; movss [rsp + offset], Rx(reg));
            }
            Type::F64 => {
                dynasm!(self.ops; movsd [rsp + offset], Rx(reg));
            }
            Type::Void | Type::Top => unreachable!(),
        }
    }

    fn gen_mov_reg_stack(&mut self, t: Type, r: u8, offset: i32) {
        match t {
            Type::Bool | Type::I8 => dynasm!(self.ops; mov Rb(r), [rsp + offset]),
            Type::I16 => dynasm!(self.ops; mov Rw(r), [rsp + offset]),
            Type::I32 => dynasm!(self.ops; mov Rd(r), [rsp + offset]),
            Type::I64 => dynasm!(self.ops; mov Rq(r), [rsp + offset]),
            Type::F32 => dynasm!(self.ops; movss Rx(r), [rsp + offset]),
            Type::F64 => dynasm!(self.ops; movsd Rx(r), [rsp + offset]),
            Type::Void | Type::Top => unreachable!(),
        }
    }

    fn gen_mov_stack_reg(&mut self, t: Type, r: u8, offset: i32) {
        match t {
            Type::Bool | Type::I8 => dynasm!(self.ops; mov [rsp + offset], Rb(r)),
            Type::I16 => dynasm!(self.ops; mov [rsp + offset], Rw(r)),
            Type::I32 => dynasm!(self.ops; mov [rsp + offset], Rd(r)),
            Type::I64 => dynasm!(self.ops; mov [rsp + offset], Rq(r)),
            Type::F32 => dynasm!(self.ops; movss [rsp + offset], Rx(r)),
            Type::F64 => dynasm!(self.ops; movsd [rsp + offset], Rx(r)),
            Type::Void | Type::Top => unreachable!(),
        }
    }

    fn save_interval(&mut self, i: usize) {
        let i = &self.cfg.liveness[i];
        use LiveIntervalValueCategory::*;
        let t = match (i.value_category.unwrap(), i.max_mem_size) {
            (Int, 1) => Type::I8,
            (Int, 2) => Type::I16,
            (Int, 4) => Type::I32,
            (Int, 8) => Type::I64,
            (Float, 4) => Type::F32,
            (Float, 8) => Type::F64,
            x => unreachable!("{:?}", x),
        };
        self.gen_mov_stack_reg(t, i.reg.unwrap() as u8, i.mem);
    }

    fn restore_interval(&mut self, i: usize) {
        let i = &self.cfg.liveness[i];
        use LiveIntervalValueCategory::*;
        let t = match (i.value_category.unwrap(), i.max_mem_size) {
            (Int, 1) => Type::I8,
            (Int, 2) => Type::I16,
            (Int, 4) => Type::I32,
            (Int, 8) => Type::I64,
            (Float, 4) => Type::F32,
            (Float, 8) => Type::F64,
            x => unreachable!("{:?}", x),
        };
        self.gen_mov_reg_stack(t, i.reg.unwrap() as u8, i.mem);
    }

    fn save_reg_if_active(&mut self, node: NodeId, reg: usize) {
        for i in 0..self.cfg.liveness.len() {
            let ival = &self.cfg.liveness[i];
            if i != self.cfg.g[node].interval
                && ival.covers(self.cfg.g[node].cfg_id)
                && ival.reg == Some(reg)
            {
                self.save_interval(i);
            }
        }
    }

    fn restore_reg_if_active(&mut self, node: NodeId, reg: usize) {
        for i in 0..self.cfg.liveness.len() {
            let ival = &self.cfg.liveness[i];
            if i != self.cfg.g[node].interval
                && ival.covers(self.cfg.g[node].cfg_id)
                && ival.reg == Some(reg)
            {
                self.restore_interval(i);
            }
        }
    }

    fn load_input_reg(&mut self, node: NodeId, tmp: u8) -> u8 {
        let interval_id = self.cfg.g[node].interval;
        assert_ne!(interval_id, usize::MAX);
        if let Some(reg) = self.cfg.liveness[interval_id].reg {
            // This node has a register
            reg as _
        } else if let Some(fixed_reg) = self.cfg.g[node].fixed_reg {
            // This node requires a fixed reg, but does not have a register assigned.
            // This means that this fixed register is actively bing used by another interval.
            // 1. Spill the active interval with fixed_reg
            self.save_reg_if_active(node, fixed_reg);
            // 2. Load value into fixed_reg
            let mem = self.cfg.liveness[interval_id].mem;
            self.gen_mov_reg_stack(self.cfg.g[node].ty, fixed_reg as u8, mem);
            fixed_reg as _
        } else {
            // This node does not have a register. Load from memory
            let mem = self.cfg.liveness[interval_id].mem;
            self.cfg.g[node].temp_reg = Some(tmp);
            self.gen_mov_reg_stack(self.cfg.g[node].ty, tmp, mem);
            tmp
        }
    }

    fn load_output_reg(&mut self, node: NodeId, tmp: u8) -> u8 {
        let interval_id = self.cfg.g[node].interval;
        assert_ne!(
            interval_id,
            usize::MAX,
            "Node does not have an reg assiged: {:?}",
            node
        );
        if let Some(reg) = self.cfg.liveness[interval_id].reg {
            // This node has a register
            reg as _
        } else if let Some(fixed_reg) = self.cfg.g[node].fixed_reg {
            // This node requires a fixed reg, but does not have a register assigned.
            // This means that this fixed register is actively bing used by another interval.
            // 1. Spill the active interval with fixed_reg
            self.save_reg_if_active(node, fixed_reg);
            // 2. Use fixed_reg
            fixed_reg as _
        } else {
            // This node does not have a register assigned. Use a temp reg
            self.cfg.g[node].temp_reg = Some(tmp);
            tmp
        }
    }

    fn update_spilled_values(&mut self, node: NodeId) {
        let interval = self.cfg.g[node].interval;
        let fixed_reg = self.cfg.g[node].fixed_reg;
        if interval == usize::MAX {
            return;
        }
        // Outputs
        if let Some(_reg) = self.cfg.liveness[interval].reg {
            // pass
        } else if let Some(fixed_reg) = fixed_reg {
            // 1. Spill fixed_reg
            let mem = self.cfg.liveness[interval].mem;
            self.gen_mov_stack_reg(self.cfg.g[node].ty, fixed_reg as u8, mem);
            // 2. Restore the active interval with fixed_reg
            for index in 0..self.cfg.liveness.len() {
                let ival = &self.cfg.liveness[index];
                if index != interval
                    && ival.covers(self.cfg.g[node].cfg_id)
                    && ival.reg == Some(fixed_reg)
                {
                    self.restore_interval(index);
                }
            }
        } else if let Some(tmp) = self.cfg.g[node].temp_reg.take() {
            let mem = self.cfg.liveness[interval].mem;
            self.gen_mov_stack_reg(self.cfg.g[node].ty, tmp, mem);
        }
        self.cfg.g[node].temp_reg = None;
    }

    fn get_successor_id(&self, succ_index: usize) -> usize {
        self.cfg.blocks[self.current_block_id].succs[succ_index]
    }

    fn get_successor_label(&self, succ_index: usize) -> DynamicLabel {
        self.labels[self.get_successor_id(succ_index)]
    }

    fn gen_shift_op(&mut self, op: Op, node: NodeId, shift_op: X64Reg) {
        let t = self.cfg.g[node].ty;
        let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
        let y = self.load_input_reg(self.cfg.g[node].inputs[1], TMP1);
        let mut tgt = self.load_output_reg(node, TMP1);
        let original_tgt = tgt;
        debug_assert_ne!(TMP1, shift_op as _);
        if tgt == shift_op as _ {
            tgt = TMP1;
        }
        if tgt != x {
            self.gen_mov_reg_reg(self.cfg.g[node].ty, tgt, x);
        }
        debug_assert_ne!(tgt, shift_op as _, "{:?} {:?}", op, self.cfg.g[node]);
        debug_assert_eq!(y, shift_op as _);
        debug_assert_ne!(tgt, shift_op as _);
        match (op, t) {
            (Op::Shl, Type::I32) => dynasm!(self.ops; sal Rd(tgt), cl),
            (Op::ShrS, Type::I32) => dynasm!(self.ops; sar Rd(tgt), cl),
            (Op::ShrU, Type::I32) => dynasm!(self.ops; shr Rd(tgt), cl),
            (Op::Rotl, Type::I32) => dynasm!(self.ops; rol Rd(tgt), cl),
            (Op::Rotr, Type::I32) => dynasm!(self.ops; ror Rd(tgt), cl),
            (Op::Shl, Type::I64) => dynasm!(self.ops; sal Rq(tgt), cl),
            (Op::ShrS, Type::I64) => dynasm!(self.ops; sar Rq(tgt), cl),
            (Op::ShrU, Type::I64) => dynasm!(self.ops; shr Rq(tgt), cl),
            (Op::Rotl, Type::I64) => dynasm!(self.ops; rol Rq(tgt), cl),
            (Op::Rotr, Type::I64) => dynasm!(self.ops; ror Rq(tgt), cl),
            x => unreachable!("{:?}", x),
        }
        if original_tgt != tgt {
            self.gen_mov_reg_reg(self.cfg.g[node].ty, original_tgt, tgt);
        }
    }

    /// Generate binary opertion
    /// The target and the first operand are the same register.
    fn gen_binop(&mut self, op: Op, node: NodeId) {
        let t = self.cfg.g[node].ty;
        let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
        let y = self.load_input_reg(self.cfg.g[node].inputs[1], TMP1);
        let mut tgt = self.load_output_reg(node, TMP0);
        let original_tgt = tgt;
        if tgt == y {
            if x != TMP0 {
                self.gen_mov_reg_reg(t, TMP0, x);
            }
            tgt = TMP0;
        } else if tgt != x {
            self.gen_mov_reg_reg(t, tgt, x);
        }
        match (op, t) {
            (Op::Add, Type::I32) => dynasm!(self.ops; add Rd(tgt), Rd(y)),
            (Op::Sub, Type::I32) => dynasm!(self.ops; sub Rd(tgt), Rd(y)),
            (Op::Mul, Type::I32) => dynasm!(self.ops; imul Rd(tgt), Rd(y)),
            (Op::And, Type::I32) => dynasm!(self.ops; and Rd(tgt), Rd(y)),
            (Op::Or, Type::I32) => dynasm!(self.ops; or Rd(tgt), Rd(y)),
            (Op::Xor, Type::I32) => dynasm!(self.ops; xor Rd(tgt), Rd(y)),
            (Op::Add, Type::I64) => dynasm!(self.ops; add Rq(tgt), Rq(y)),
            (Op::Sub, Type::I64) => dynasm!(self.ops; sub Rq(tgt), Rq(y)),
            (Op::Mul, Type::I64) => dynasm!(self.ops; imul Rq(tgt), Rq(y)),
            (Op::And, Type::I64) => dynasm!(self.ops; and Rq(tgt), Rq(y)),
            (Op::Or, Type::I64) => dynasm!(self.ops; or Rq(tgt), Rq(y)),
            (Op::Xor, Type::I64) => dynasm!(self.ops; xor Rq(tgt), Rq(y)),
            (Op::Add, Type::F32) => dynasm!(self.ops; addss Rx(tgt), Rx(y)),
            (Op::Sub, Type::F32) => dynasm!(self.ops; subss Rx(tgt), Rx(y)),
            (Op::Mul, Type::F32) => dynasm!(self.ops; mulss Rx(tgt), Rx(y)),
            (Op::FDiv, Type::F32) => dynasm!(self.ops; divss Rx(tgt), Rx(y)),
            (Op::Add, Type::F64) => dynasm!(self.ops; addsd Rx(tgt), Rx(y)),
            (Op::Sub, Type::F64) => dynasm!(self.ops; subsd Rx(tgt), Rx(y)),
            (Op::Mul, Type::F64) => dynasm!(self.ops; mulsd Rx(tgt), Rx(y)),
            (Op::FDiv, Type::F64) => dynasm!(self.ops; divsd Rx(tgt), Rx(y)),
            x => unreachable!("{:?}", x),
        }
        if original_tgt == y {
            self.gen_mov_reg_reg(t, original_tgt, TMP0);
        }
    }

    fn gen_div(&mut self, op: Op, node: NodeId) {
        let t = self.cfg.g[node].ty;
        let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
        let y = self.load_input_reg(self.cfg.g[node].inputs[1], TMP1);
        let tgt = self.load_output_reg(node, TMP0);
        debug_assert_eq!(x, X64Reg::RAX as _);
        debug_assert_ne!(y, X64Reg::RDX as _);
        debug_assert_ne!(y, X64Reg::RAX as _);
        debug_assert_eq!(tgt, X64Reg::RAX as _);
        self.save_reg_if_active(node, X64Reg::RDX as _);
        match (op, t) {
            (Op::DivS, Type::I32) => {
                dynasm!(self.ops; cdq);
                dynasm!(self.ops; idiv Rd(y));
            }
            (Op::DivU, Type::I32) => {
                dynasm!(self.ops; xor edx, edx);
                dynasm!(self.ops; div Rd(y));
            }
            (Op::DivS, Type::I64) => {
                dynasm!(self.ops; cqo);
                dynasm!(self.ops; idiv Rq(y));
            }
            (Op::DivU, Type::I64) => {
                dynasm!(self.ops; xor rdx, rdx);
                dynasm!(self.ops; div Rq(y));
            }
            _ => unreachable!(),
        }
        self.restore_reg_if_active(node, X64Reg::RDX as _);
    }

    fn gen_irem(&mut self, op: Op, node: NodeId) {
        let t = self.cfg.g[node].ty;
        let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
        let y = self.load_input_reg(self.cfg.g[node].inputs[1], TMP1);
        let tgt = self.load_output_reg(node, TMP0);
        debug_assert_eq!(x, X64Reg::RAX as _);
        debug_assert_ne!(y, X64Reg::RDX as _);
        debug_assert_ne!(y, X64Reg::RAX as _);
        debug_assert_eq!(tgt, X64Reg::RDX as _);
        match (op, t) {
            (Op::RemS, Type::I32) => {
                dynasm! { self.ops
                    ; cmp Rd(x), DWORD i32::MIN
                    ; jne >do_div
                    ; cmp Rd(y), DWORD -1
                    ; jne >do_div
                ; set_zero:
                    ; xor edx, edx
                    ; jmp >end
                ; do_div:
                    ; cdq
                    ; idiv Rd(y)
                ; end:
                };
            }
            (Op::RemU, Type::I32) => {
                dynasm! { self.ops
                    ; xor edx, edx
                    ; div Rd(y)
                };
            }
            (Op::RemS, Type::I64) => {
                dynasm! { self.ops
                    ; mov Rq(TMP1), QWORD i64::MIN
                    ; cmp Rq(x), Rq(TMP1)
                    ; jne >do_div
                    ; mov Rq(TMP1), QWORD -1
                    ; cmp Rq(y), Rq(TMP1)
                    ; jne >do_div
                ; set_zero:
                    ; xor rdx, rdx
                    ; jmp >end
                ; do_div:
                    ; cqo
                    ; idiv Rq(y)
                ; end:
                };
            }
            (Op::RemU, Type::I64) => {
                dynasm! { self.ops
                    ; xor rdx, rdx
                    ; div Rq(y)
                };
            }
            _ => unreachable!(),
        }
    }

    fn gen_bitcnt(&mut self, op: Op, node: NodeId) {
        let t = self.cfg.g[self.cfg.g[node].inputs[0]].ty;
        let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
        let tgt = self.load_output_reg(node, TMP0);
        match (op, t) {
            (Op::Clz, Type::I32) => {
                dynasm! { self.ops
                    ; cmp Rd(x), DWORD 0
                    ; je >zero_src
                    ; bsr Rd(tgt), Rd(x)
                    ; not Rd(tgt)
                    ; and Rd(tgt), DWORD 0b11111
                    ; jmp >end
                ; zero_src:
                    ; mov Rd(tgt), DWORD 32
                ; end:
                };
            }
            (Op::Clz, Type::I64) => {
                dynasm! { self.ops
                    ; cmp Rq(x), DWORD 0
                    ; je >zero_src
                    ; bsr Rq(tgt), Rq(x)
                    ; not Rq(tgt)
                    ; and Rq(tgt), DWORD 0b111111
                    ; jmp >end
                ; zero_src:
                    ; mov Rq(tgt), DWORD 64
                ; end:
                };
            }
            (Op::Ctz, Type::I32) => {
                dynasm! { self.ops
                    ; cmp Rd(x), DWORD 0
                    ; je >zero_src
                    ; bsf Rd(tgt), Rd(x)
                    ; jmp >end
                ; zero_src:
                    ; mov Rd(tgt), DWORD 32
                ; end:
                };
            }
            (Op::Ctz, Type::I64) => {
                dynasm! { self.ops
                    ; cmp Rq(x), DWORD 0
                    ; je >zero_src
                    ; bsf Rq(tgt), Rq(x)
                    ; jmp >end
                ; zero_src:
                    ; mov Rq(tgt), DWORD 64
                ; end:
                };
            }
            (Op::Popcnt, Type::I32) => dynasm!(self.ops; popcnt Rd(tgt), Rd(x)),
            (Op::Popcnt, Type::I64) => dynasm!(self.ops; popcnt Rq(tgt), Rq(x)),
            _ => unimplemented!(),
        }
    }

    fn gen_cmp(&mut self, node: NodeId) {
        let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
        let y = self.load_input_reg(self.cfg.g[node].inputs[1], TMP1);
        let tgt = self.load_output_reg(node, TMP0);
        match self.cfg.g[self.cfg.g[node].inputs[0]].ty {
            Type::I32 => dynasm!(self.ops; cmp Rd(x), Rd(y)),
            Type::I64 => dynasm!(self.ops; cmp Rq(x), Rq(y)),
            Type::F32 => dynasm!(self.ops; comiss Rx(x), Rx(y)),
            Type::F64 => dynasm!(self.ops; comisd Rx(x), Rx(y)),
            t => unimplemented!("{:?}", t),
        }
        match (
            self.cfg.g[node].op::<Op>(),
            self.cfg.g[self.cfg.g[node].inputs[0]].ty,
        ) {
            (Op::Eq, Type::I32 | Type::I64) => dynasm!(self.ops; sete Rb(tgt)),
            (Op::Ne, Type::I32 | Type::I64) => dynasm!(self.ops; setne Rb(tgt)),
            (Op::LtS, Type::I32 | Type::I64) => dynasm!(self.ops; setl Rb(tgt)),
            (Op::LtU, Type::I32 | Type::I64) => dynasm!(self.ops; setb Rb(tgt)),
            (Op::LeS, Type::I32 | Type::I64) => dynasm!(self.ops; setle Rb(tgt)),
            (Op::LeU, Type::I32 | Type::I64) => dynasm!(self.ops; setbe Rb(tgt)),
            (Op::GtS, Type::I32 | Type::I64) => dynasm!(self.ops; setg Rb(tgt)),
            (Op::GtU, Type::I32 | Type::I64) => dynasm!(self.ops; seta Rb(tgt)),
            (Op::GeS, Type::I32 | Type::I64) => dynasm!(self.ops; setge Rb(tgt)),
            (Op::GeU, Type::I32 | Type::I64) => dynasm!(self.ops; setae Rb(tgt)),

            (Op::Eq, Type::F32 | Type::F64) => dynasm! { self.ops
                ; mov    Rd(TMP1), 0
                ; sete   Rb(tgt)
                ; cmovp  Rd(tgt), Rd(TMP1)
            },
            (Op::Ne, Type::F32 | Type::F64) => dynasm! { self.ops
                ; mov    Rd(TMP1), 1
                ; setne  Rb(tgt)
                ; cmovp  Rd(tgt), Rd(TMP1)
            },
            (Op::LtF, Type::F32 | Type::F64) => dynasm! { self.ops
                ; mov    Rd(TMP1), 0
                ; setb   Rb(tgt)
                ; cmovp  Rd(tgt), Rd(TMP1)
            },
            (Op::LeF, Type::F32 | Type::F64) => dynasm! { self.ops
                ; mov    Rd(TMP1), 0
                ; setbe  Rb(tgt)
                ; cmovp  Rd(tgt), Rd(TMP1)
            },
            (Op::GtF, Type::F32 | Type::F64) => dynasm! { self.ops
                ; mov    Rd(TMP1), 0
                ; seta   Rb(tgt)
                ; cmovp  Rd(tgt), Rd(TMP1)
            },
            (Op::GeF, Type::F32 | Type::F64) => dynasm! { self.ops
                ; mov    Rd(TMP1), 0
                ; setae  Rb(tgt)
                ; cmovp  Rd(tgt), Rd(TMP1)
            },
            x => unimplemented!("{:?}", x),
        }
        assert_eq!(self.cfg.g[node].ty, Type::Bool);
    }

    fn gen_node(&mut self, node: NodeId) {
        let op = self.cfg.g[node].op::<Op>();
        match op {
            Op::Start => self.gen_prologue(),
            Op::Param if self.cfg.g[node].fixed_reg.is_none() => {
                let stack_arg_index = self.cfg.g[node].stack_arg_index.unwrap() as i32;
                let tgt = self.load_output_reg(node, TMP0);
                let offset = 16 + (stack_arg_index << 3);
                match self.cfg.g[node].ty {
                    Type::Bool | Type::I8 | Type::I16 | Type::I32 | Type::I64 => {
                        dynasm!(self.ops; mov Rq(tgt), [rbp + offset])
                    }
                    Type::F32 => dynasm!(self.ops; movss Rx(tgt), [rbp + offset]),

                    Type::F64 => dynasm!(self.ops; movsd Rx(tgt), [rbp + offset]),

                    Type::Void | Type::Top => unreachable!(),
                }
            }
            Op::Region | Op::Param | Op::Phi | Op::EffectPhi => {
                // do nothing.
            }
            Op::ITruncU => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                if x != tgt {
                    warn!("ITruncU is not coalesced");
                    dynasm!(self.ops; mov Rq(tgt), Rq(x));
                }
            }
            Op::Wrap => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                dynasm!(self.ops; mov Rd(tgt), Rd(x));
            }
            Op::CvtF2SI | Op::CvtF2UI | Op::CvtSI2F | Op::CvtUI2F => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                match (
                    op,
                    self.cfg.g[node].ty,
                    self.cfg.g[self.cfg.g[node].inputs[0]].ty,
                ) {
                    (Op::CvtF2SI, Type::I32, Type::F32) => {
                        dynasm!(self.ops; cvttss2si Rd(tgt), Rx(x))
                    }
                    (Op::CvtF2SI, Type::I32, Type::F64) => {
                        dynasm!(self.ops; cvttsd2si Rd(tgt), Rx(x))
                    }
                    (Op::CvtF2SI, Type::I64, Type::F32) => {
                        dynasm!(self.ops; cvttss2si Rq(tgt), Rx(x))
                    }
                    (Op::CvtF2SI, Type::I64, Type::F64) => {
                        dynasm!(self.ops; cvttsd2si Rq(tgt), Rx(x))
                    }
                    (Op::CvtF2UI, Type::I32, Type::F32) => {
                        let label = self.register_constant(Const::F32(u64::MAX as _));
                        dynasm! { self.ops
                            ; mov Rd(TMP1), DWORD -1
                            ; cvtsi2ss Rx(TMP1), Rd(TMP1)
                            ; comiss Rx(x), Rx(TMP1)
                            ; jbe >except
                            ; cvttss2si Rq(tgt), Rx(x)
                            ; mov r11d, DWORD -1
                            ; cmp Rq(tgt), r11
                            ; ja >except
                            ; jmp >end
                        ; except:
                            ; movss Rx(TMP1), [=>label]
                            ; cvttss2si Rq(tgt), Rx(TMP1)
                        ; end:
                        }
                    }
                    (Op::CvtF2UI, Type::I32, Type::F64) => {
                        let label = self.register_constant(Const::F32(u64::MAX as _));
                        dynasm! { self.ops
                            ; mov Rd(TMP1), DWORD -1
                            ; cvtsi2sd Rx(TMP1), Rd(TMP1)
                            ; comisd Rx(x), Rx(TMP1)
                            ; jbe >except
                            ; cvttsd2si Rq(tgt), Rx(x)
                            ; mov r11d, DWORD -1
                            ; cmp Rq(tgt), r11
                            ; ja >except
                            ; jmp >end
                        ; except:
                            ; movss Rx(TMP1), [=>label]
                            ; cvttss2si Rq(tgt), Rx(TMP1)
                        ; end:
                        }
                    }
                    (Op::CvtF2UI, Type::I64, Type::F32) => {
                        let label = self.register_constant(Const::F32((i64::MAX as u64 + 1) as _));
                        dynasm! { self.ops
                            ; mov Rd(TMP1), DWORD -1
                            ; cvtsi2ss Rx(TMP1), Rd(TMP1)
                            ; comiss Rx(x), Rx(TMP1)
                            ; jbe >except
                            ; movss Rx(TMP1), [=>label]
                            ; ucomiss Rx(x), Rx(TMP1)
                            ; jae >sub
                            ; cvttss2si Rq(tgt), Rx(x)
                            ; jmp >end
                        ; sub:
                            ; subss Rx(x), Rx(TMP1)
                            ; cvttss2si Rq(tgt), Rx(x)
                            ; mov Rq(TMP1), QWORD -0x8000000000000000
                            ; or Rq(tgt), Rq(TMP1)
                            ; jmp >end
                        ; except:
                            ; movss Rx(TMP1), [=>label]
                            ; cvttss2si Rq(tgt), Rx(TMP1)
                        ; end:
                        }
                    }
                    (Op::CvtF2UI, Type::I64, Type::F64) => {
                        let label = self.register_constant(Const::F64((i64::MAX as u64 + 1) as _));
                        let label2 = self.register_constant(Const::F32(u64::MAX as _));
                        dynasm! { self.ops
                            ; mov Rd(TMP1), DWORD -1
                            ; cvtsi2sd Rx(TMP1), Rd(TMP1)
                            ; comisd Rx(x), Rx(TMP1)
                            ; jbe >except
                            ; movsd Rx(TMP1), [=>label]
                            ; ucomisd Rx(x), Rx(TMP1)
                            ; jae >sub
                            ; cvttsd2si Rq(tgt), Rx(x)
                            ; jmp >end
                        ; sub:
                            ; subsd Rx(x), Rx(TMP1)
                            ; cvttsd2si Rq(tgt), Rx(x)
                            ; mov Rq(TMP1), QWORD -0x8000000000000000
                            ; or Rq(tgt), Rq(TMP1)
                            ; jmp >end
                        ; except:
                            ; movss Rx(TMP1), [=>label2]
                            ; cvttss2si Rq(tgt), Rx(TMP1)
                        ; end:
                        }
                    }
                    (Op::CvtSI2F, Type::F32, Type::I32) => {
                        dynasm!(self.ops; pxor Rx(tgt), Rx(tgt));
                        dynasm!(self.ops; cvtsi2ss Rx(tgt), Rd(x));
                    }
                    (Op::CvtSI2F, Type::F32, Type::I64) => {
                        dynasm!(self.ops; pxor Rx(tgt), Rx(tgt));
                        dynasm!(self.ops; cvtsi2ss Rx(tgt), Rq(x));
                    }
                    (Op::CvtSI2F, Type::F64, Type::I32) => {
                        dynasm!(self.ops; pxor Rx(tgt), Rx(tgt));
                        dynasm!(self.ops; cvtsi2sd Rx(tgt), Rd(x));
                    }
                    (Op::CvtSI2F, Type::F64, Type::I64) => {
                        dynasm!(self.ops; pxor Rx(tgt), Rx(tgt));
                        dynasm!(self.ops; cvtsi2sd Rx(tgt), Rq(x));
                    }
                    (Op::CvtUI2F, Type::F32, Type::I32) => {
                        dynasm! { self.ops
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2ss Rx(tgt), Rd(x)
                            ; test Rd(x), Rd(x)
                            ; js >s
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2ss Rx(tgt), Rd(x)
                            ; jmp >end
                        ; s: // tmp1 = (x >> 1) | (x & 1)
                            ; push Rq(x)
                            ; mov Rd(TMP1), Rd(x)
                            ; and Rd(TMP1), 1
                            ; shr Rd(x), 1
                            ; or  Rd(x), Rd(TMP1)
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2ss Rx(tgt), Rd(x)
                            ; addss Rx(tgt), Rx(tgt)
                            ; cvtsi2ss Rx(TMP1), Rd(TMP1)
                            ; addss Rx(tgt), Rx(TMP1)
                            ; pop Rq(x)
                        ; end:
                        }
                    }
                    (Op::CvtUI2F, Type::F32, Type::I64) => {
                        dynasm! { self.ops
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2ss Rx(tgt), Rq(x)
                            ; test Rq(x), Rq(x)
                            ; js >s
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2ss Rx(tgt), Rq(x)
                            ; jmp >end
                        ; s: // tmp0 = (x >> 1) | (x & 1)
                            ; push Rq(x)
                            ; mov Rd(TMP1), Rd(x)
                            ; and Rd(TMP1), 1
                            ; shr Rq(x), 1
                            ; or  Rq(x), Rq(TMP1)
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2ss Rx(tgt), Rq(x)
                            ; addss Rx(tgt), Rx(tgt)
                            ; cvtsi2ss Rx(TMP1), Rd(TMP1)
                            ; addss Rx(tgt), Rx(TMP1)
                            ; pop Rq(x)
                        ; end:
                        }
                    }
                    (Op::CvtUI2F, Type::F64, Type::I32) => {
                        dynasm! { self.ops
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2sd Rx(tgt), Rd(x)
                            ; test Rd(x), Rd(x)
                            ; js >s
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2sd Rx(tgt), Rd(x)
                            ; jmp >end
                        ; s: // tmp0 = (x >> 1) | (x & 1)
                            ; push Rq(x)
                            ; mov Rd(TMP1), Rd(x)
                            ; and Rd(TMP1), 1
                            ; shr Rd(x), 1
                            ; or  Rd(x), Rd(TMP1)
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2sd Rx(tgt), Rd(x)
                            ; addsd Rx(tgt), Rx(tgt)
                            ; cvtsi2sd Rx(TMP1), Rd(TMP1)
                            ; addsd Rx(tgt), Rx(TMP1)
                            ; pop Rq(x)
                        ; end:
                        }
                    }
                    (Op::CvtUI2F, Type::F64, Type::I64) => {
                        dynasm! { self.ops
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2sd Rx(tgt), Rq(x)
                            ; test Rq(x), Rq(x)
                            ; js >s
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2sd Rx(tgt), Rq(x)
                            ; jmp >end
                        ; s: // tmp0 = (x >> 1) | (x & 1)
                            ; push Rq(x)
                            ; mov Rd(TMP1), Rd(x)
                            ; and Rd(TMP1), 1
                            ; shr Rq(x), 1
                            ; or  Rq(x), Rq(TMP1)
                            ; pxor Rx(tgt), Rx(tgt)
                            ; cvtsi2sd Rx(tgt), Rq(x)
                            ; addsd Rx(tgt), Rx(tgt)
                            ; cvtsi2sd Rx(TMP1), Rd(TMP1)
                            ; addsd Rx(tgt), Rx(TMP1)
                            ; pop Rq(x)
                        ; end:
                        }
                    }
                    _ => unreachable!(),
                }
            }
            Op::CvtF2F => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                if self.cfg.g[self.cfg.g[node].inputs[0]].ty == self.cfg.g[node].ty {
                    // do nothing
                } else if self.cfg.g[node].ty == Type::F64 {
                    // promote
                    dynasm!(self.ops; cvtss2sd Rx(tgt), Rx(x));
                } else {
                    // deomote
                    dynasm!(self.ops; cvtsd2ss Rx(tgt), Rx(x));
                }
            }
            Op::Bitcast => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                match (
                    self.cfg.g[node].ty,
                    self.cfg.g[self.cfg.g[node].inputs[0]].ty,
                ) {
                    (Type::F32, Type::I32) => dynasm!(self.ops; movd Rx(tgt), Rd(x)),
                    (Type::I32, Type::F32) => dynasm!(self.ops; movd Rd(tgt), Rx(x)),
                    (Type::F64, Type::I64) => dynasm!(self.ops; movq Rx(tgt), Rq(x)),
                    (Type::I64, Type::F64) => dynasm!(self.ops; movq Rq(tgt), Rx(x)),
                    _ => unreachable!(),
                }
            }
            Op::Const => {
                let v = match self.cfg.g[node].literal.as_ref().unwrap() {
                    Literal::Value(v) => v.clone(),
                    _ => unreachable!(),
                };
                let tgt = self.load_output_reg(node, TMP0);
                match v {
                    Const::Bool(v) => dynasm!(self.ops; mov Rb(tgt), BYTE v as _),
                    Const::I32(v) => dynasm!(self.ops; mov Rd(tgt), DWORD v as _),
                    Const::I64(v) => dynasm!(self.ops; fs mov Rq(tgt), QWORD v as _),
                    Const::F32(v) => {
                        let v = unsafe { std::mem::transmute::<f32, i32>(v) };
                        dynasm! {self.ops
                            ; mov Rd(TMP1), DWORD v
                            ; movd Rx(tgt), Rd(TMP1)
                        }
                    }
                    Const::F64(v) => {
                        let v = unsafe { std::mem::transmute::<f64, i64>(v) };
                        dynasm! {self.ops
                            ; mov Rq(TMP1), QWORD v
                            ; movq Rx(tgt), Rq(TMP1)
                        }
                    }
                    _ => unimplemented!("{:?}", v),
                }
            }
            Op::Move => {
                let o = &self.cfg.liveness[self.cfg.g[node].interval];
                let i = &self.cfg.liveness[self.cfg.g[self.cfg.g[node].inputs[0]].interval];
                if !((i.reg.is_some() && i.reg == o.reg)
                    || (i.reg.is_none() && o.reg.is_none() && i.mem == o.mem))
                {
                    if o.reg.is_some() && i.reg.is_some() {
                        // both input and output are in regs
                        self.gen_mov_reg_reg(
                            self.cfg.g[node].ty,
                            o.reg.unwrap() as _,
                            i.reg.unwrap() as _,
                        );
                    } else if o.reg.is_none() && i.reg.is_none() {
                        // both input and output are in spilled
                        let (i_mem, o_mem) = (i.mem, o.mem);
                        self.gen_mov_reg_stack(self.cfg.g[node].ty, TMP0, i_mem);
                        self.gen_mov_stack_reg(self.cfg.g[node].ty, TMP0, o_mem);
                    } else if o.reg.is_none() {
                        // output is in spilled
                        self.gen_mov_stack_reg(self.cfg.g[node].ty, i.reg.unwrap() as _, o.mem);
                    } else if !o.reg.is_none() && i.reg.is_none() {
                        // input is in spilled
                        self.gen_mov_reg_stack(self.cfg.g[node].ty, o.reg.unwrap() as _, i.mem);
                    }
                }
            }
            Op::Not => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                assert_eq!(self.cfg.g[node].ty, Type::Bool);
                dynasm! { self.ops
                    ; mov Rb(tgt), Rb(x)
                    ; xor Rb(tgt), 1
                };
            }
            Op::Neg => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                match self.cfg.g[node].ty {
                    Type::I8 | Type::I16 | Type::I32 => {
                        if x != tgt {
                            dynasm!(self.ops; mov Rd(tgt), Rd(x));
                        }
                        dynasm!(self.ops; neg Rd(tgt));
                    }
                    Type::I64 => {
                        if x != tgt {
                            dynasm!(self.ops; mov Rq(tgt), Rq(x));
                        }
                        dynasm!(self.ops; neg Rq(tgt));
                    }
                    Type::F32 => {
                        if x != tgt {
                            dynasm!(self.ops; movss Rx(tgt), Rx(x));
                        }
                        let label = self.register_constant(Const::I128(unsafe {
                            std::mem::transmute(0x8000000080000000_8000000080000000u128)
                        }));
                        dynasm! {self.ops
                            ; xorps Rx(tgt), [=>label]
                        }
                    }
                    Type::F64 => {
                        if x != tgt {
                            dynasm!(self.ops; movsd Rx(tgt), Rx(x));
                        }
                        let label = self.register_constant(Const::I128(unsafe {
                            std::mem::transmute(0x8000000000000000_8000000000000000u128)
                        }));
                        dynasm! {self.ops
                            ; xorpd Rx(tgt), [=>label]
                        }
                    }
                    _ => unreachable!(),
                }
            }
            Op::Add | Op::Sub | Op::Mul | Op::And | Op::Or | Op::Xor => self.gen_binop(op, node),
            Op::FDiv => self.gen_binop(op, node),
            Op::DivS | Op::DivU => self.gen_div(op, node),
            Op::RemS | Op::RemU => self.gen_irem(op, node),
            Op::Shl | Op::ShrS | Op::ShrU | Op::Rotl | Op::Rotr => {
                self.gen_shift_op(op, node, X64Reg::RCX)
            }
            Op::Clz | Op::Ctz | Op::Popcnt => self.gen_bitcnt(op, node),
            Op::SExt => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                match (
                    self.cfg.g[self.cfg.g[node].inputs[0]].ty,
                    self.cfg.g[node].ty,
                ) {
                    (Type::I8 | Type::Bool, Type::I32) => dynasm!(self.ops; movsx Rd(tgt), Rb(x)),
                    (Type::I16, Type::I32) => dynasm!(self.ops; movsx Rd(tgt), Rw(x)),
                    (Type::I8 | Type::Bool, Type::I64) => dynasm!(self.ops; movsx Rq(tgt), Rb(x)),
                    (Type::I16, Type::I64) => dynasm!(self.ops; movsx Rq(tgt), Rw(x)),
                    (Type::I32, Type::I64) => dynasm!(self.ops; movsx Rq(tgt), Rd(x)),
                    _ => unimplemented!(),
                }
            }
            Op::ZExt => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                match (
                    self.cfg.g[self.cfg.g[node].inputs[0]].ty,
                    self.cfg.g[node].ty,
                ) {
                    (Type::I8 | Type::Bool, Type::I32) => dynasm!(self.ops; movzx Rd(tgt), Rb(x)),
                    (Type::I16, Type::I32) => dynasm!(self.ops; movzx Rd(tgt), Rw(x)),
                    (Type::I8 | Type::Bool, Type::I64) => dynasm!(self.ops; movzx Rq(tgt), Rb(x)),
                    (Type::I16, Type::I64) => dynasm!(self.ops; movzx Rq(tgt), Rw(x)),
                    (Type::I32, Type::I64) => dynasm!(self.ops; mov Rd(tgt), Rd(x)),
                    _ => unimplemented!(),
                }
            }
            Op::FSqrt => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                match self.cfg.g[node].ty {
                    Type::F32 => dynasm!(self.ops; sqrtps Rx(tgt), Rx(x)),
                    Type::F64 => dynasm!(self.ops; sqrtpd Rx(tgt), Rx(x)),
                    _ => unimplemented!(),
                }
            }
            Op::FRound | Op::FFloor | Op::FCeil | Op::FTrunc => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                match (op, self.cfg.g[node].ty) {
                    (Op::FRound, Type::F32) => dynasm!(self.ops; roundss Rx(tgt), Rx(x), BYTE 0b00),
                    (Op::FRound, Type::F64) => dynasm!(self.ops; roundsd Rx(tgt), Rx(x), BYTE 0b00),
                    (Op::FFloor, Type::F32) => dynasm!(self.ops; roundss Rx(tgt), Rx(x), BYTE 0b01),
                    (Op::FFloor, Type::F64) => dynasm!(self.ops; roundsd Rx(tgt), Rx(x), BYTE 0b01),
                    (Op::FCeil, Type::F32) => dynasm!(self.ops; roundss Rx(tgt), Rx(x), BYTE 0b10),
                    (Op::FCeil, Type::F64) => dynasm!(self.ops; roundsd Rx(tgt), Rx(x), BYTE 0b10),
                    (Op::FTrunc, Type::F32) => dynasm!(self.ops; roundss Rx(tgt), Rx(x), BYTE 0b11),
                    (Op::FTrunc, Type::F64) => dynasm!(self.ops; roundsd Rx(tgt), Rx(x), BYTE 0b11),
                    _ => unimplemented!(),
                }
            }
            Op::FAbs => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                match self.cfg.g[node].ty {
                    Type::F32 => {
                        let label = self.register_constant(Const::I128(unsafe {
                            std::mem::transmute(0x8000000080000000_8000000080000000u128)
                        }));
                        if x != tgt {
                            dynasm!(self.ops; movss Rx(tgt), Rx(x));
                        }
                        dynasm! {self.ops
                            ; pxor    Rx(TMP1), Rx(TMP1)
                            ; comiss  Rx(tgt),  Rx(TMP1)
                            ; jb  >neg
                            ; jmp >end
                        ; neg:
                            ; xorps   Rx(tgt), [=>label]
                        ; end:
                        }
                    }
                    Type::F64 => {
                        let label = self.register_constant(Const::I128(unsafe {
                            std::mem::transmute(0x8000000000000000_8000000000000000u128)
                        }));
                        if x != tgt {
                            dynasm!(self.ops; movsd Rx(tgt), Rx(x));
                        }
                        dynasm! {self.ops
                            ; pxor    Rx(TMP1), Rx(TMP1)
                            ; comisd  Rx(tgt),  Rx(TMP1)
                            ; jb  >neg
                            ; jmp >end
                        ; neg:
                            ; xorpd   Rx(tgt), [=>label]
                        ; end:
                        }
                    }
                    _ => unimplemented!(),
                }
            }
            Op::FCopysign => {
                let mag = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let sgn = self.load_input_reg(self.cfg.g[node].inputs[1], TMP1);
                let tgt = self.load_output_reg(node, TMP0);
                match self.cfg.g[node].ty {
                    Type::F32 => {
                        let label = self.register_constant(Const::I128(unsafe {
                            std::mem::transmute(0x8000000080000000_8000000080000000u128)
                        }));
                        let label2 = self.register_constant(Const::I128(unsafe {
                            std::mem::transmute(0x7fffffff7fffffff_7fffffff7fffffffu128)
                        }));
                        if mag != tgt {
                            dynasm!(self.ops; movss Rx(tgt), Rx(mag));
                        }
                        dynasm! {self.ops
                            ; andps   Rx(sgn), [=>label]
                            ; andps   Rx(tgt), [=>label2]
                            ; orps    Rx(tgt), Rx(sgn)
                        }
                    }
                    Type::F64 => {
                        let label = self.register_constant(Const::I128(unsafe {
                            std::mem::transmute(0x8000000000000000_8000000000000000u128)
                        }));
                        let label2 = self.register_constant(Const::I128(unsafe {
                            std::mem::transmute(0x7fffffffffffffff_7fffffffffffffffu128)
                        }));
                        if mag != tgt {
                            dynasm!(self.ops; movsd Rx(tgt), Rx(mag));
                        }
                        dynasm! {self.ops
                            ; andpd   Rx(sgn), [=>label]
                            ; andpd   Rx(tgt), [=>label2]
                            ; orpd    Rx(tgt), Rx(sgn)
                        }
                    }
                    _ => unimplemented!(),
                }
            }
            Op::Load => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                match self.cfg.g[node].ty {
                    Type::I8 => dynasm!(self.ops; mov Rb(tgt), [Rq(x)]),
                    Type::I16 => dynasm!(self.ops; mov Rw(tgt), [Rq(x)]),
                    Type::I32 => dynasm!(self.ops; mov Rd(tgt), [Rq(x)]),
                    Type::I64 => dynasm!(self.ops; mov Rq(tgt), [Rq(x)]),
                    Type::F32 => dynasm!(self.ops; movss Rx(tgt), [Rq(x)]),
                    Type::F64 => dynasm!(self.ops; movsd Rx(tgt), [Rq(x)]),
                    _ => unimplemented!(),
                }
            }
            Op::Store => {
                let ptr = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let val = self.load_input_reg(self.cfg.g[node].inputs[1], TMP1);
                match self.cfg.g[self.cfg.g[node].inputs[1]].ty {
                    Type::I8 => dynasm!(self.ops; mov [Rq(ptr)], Rb(val)),
                    Type::I16 => dynasm!(self.ops; mov [Rq(ptr)], Rw(val)),
                    Type::I32 => dynasm!(self.ops; mov [Rq(ptr)], Rd(val)),
                    Type::I64 => dynasm!(self.ops; mov [Rq(ptr)], Rq(val)),
                    Type::F32 => dynasm!(self.ops; movss [Rq(ptr)], Rx(val)),
                    Type::F64 => dynasm!(self.ops; movsd [Rq(ptr)], Rx(val)),
                    _ => unimplemented!("{:?}", self.cfg.g[node].ty),
                }
            }
            Op::Eq
            | Op::Ne
            | Op::LtS
            | Op::LtU
            | Op::LeS
            | Op::LeU
            | Op::GtS
            | Op::GtU
            | Op::GeS
            | Op::GeU
            | Op::LtF
            | Op::LeF
            | Op::GtF
            | Op::GeF => self.gen_cmp(node),
            Op::IsNan => {
                let x = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let tgt = self.load_output_reg(node, TMP0);
                match self.cfg.g[self.cfg.g[node].inputs[0]].ty {
                    Type::F32 => dynasm!(self.ops; ucomiss Rx(x), Rx(x)),
                    Type::F64 => dynasm!(self.ops; ucomisd Rx(x), Rx(x)),
                    t => unimplemented!("{:?}", t),
                }
                dynasm!(self.ops; setp Rb(tgt));
                assert_eq!(self.cfg.g[node].ty, Type::Bool);
            }
            Op::Call | Op::CallIndirect => {
                // Save active registers
                let mut saved_intervals = vec![];
                for i in 0..self.cfg.liveness.len() {
                    let interval = &self.cfg.liveness[i];
                    if i != self.cfg.g[node].interval
                        && interval.covers(self.cfg.g[node].cfg_id)
                        && interval.reg.is_some()
                    {
                        saved_intervals.push(i);
                        self.save_interval(i);
                    }
                }
                let args_start_index = match op {
                    // The first argument is the function pointer
                    // The second argument is the context word
                    Op::CallIndirect if self.cfg.g[node].has_call_indirect_ctx => 2,
                    // The first argument is the function pointer
                    Op::CallIndirect if !self.cfg.g[node].has_call_indirect_ctx => 1,
                    _ => 0,
                };
                let fptr = if op == Op::CallIndirect {
                    // get function pointer
                    let fptr = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                    // prepare context payload
                    if self.cfg.g[node].has_call_indirect_ctx {
                        let _ctx = self.load_input_reg(self.cfg.g[node].inputs[1], TMP1);
                    }
                    Some(fptr)
                } else {
                    None
                };
                // prepare args if they're not in the correct register
                let mut stack_args = vec![];
                for i in 0..self.cfg.g[node].inputs[args_start_index..].len() {
                    let a = self.cfg.g[node].inputs[args_start_index + i];
                    if let Some(fixed_reg) = self.cfg.g[a].fixed_reg {
                        let fixed_reg = fixed_reg as u8;
                        if self.cfg.g[a].fixed_reg != self.cfg.liveness[self.cfg.g[a].interval].reg
                        {
                            if let Some(reg) = self.cfg.liveness[self.cfg.g[a].interval].reg {
                                self.gen_mov_reg_reg(self.cfg.g[a].ty, fixed_reg, reg as u8);
                            } else {
                                let mem = self.cfg.liveness[self.cfg.g[a].interval].mem;
                                self.gen_mov_reg_stack(self.cfg.g[a].ty, fixed_reg, mem);
                            }
                        }
                    } else {
                        // push arg to the stack
                        stack_args.push(a);
                    }
                }
                if !stack_args.is_empty() {
                    let rsp_delta = stack_args.len() << 3;
                    for (i, a) in stack_args.iter().enumerate() {
                        self.gen_push(*a, i as _, rsp_delta as i32);
                    }
                    dynasm!(self.ops; sub rsp, DWORD rsp_delta as i32);
                }
                // Do the call.
                if op == Op::CallIndirect {
                    dynasm!(self.ops; call Rq(fptr.unwrap()));
                } else if let Literal::Func(Symbol::ExternFn(ptr)) =
                    self.cfg.g[node].literal.clone().unwrap()
                {
                    dynasm! { self.ops
                        ; fs mov rax, QWORD ptr as i64
                        ; call rax
                    };
                } else {
                    // Set the callee address to 0/NULL for now.
                    // The callee address will be patched later either when doing whole-program linking, or lazy compilation.
                    dynasm!(self.ops; call DWORD 0);
                    // Record relocation info
                    let symbol = match self.cfg.g[node].literal.as_ref().unwrap() {
                        Literal::Func(name) => name.clone(),
                        _ => unreachable!(),
                    };
                    let offset = self.ops.offset().0;
                    self.record_static_callsite(symbol, offset);
                }
                // Move return value if RAX/XMM0 is not assigned to the call node
                debug_assert!(self.cfg.g[node].fixed_reg.is_some());
                if self.cfg.g[node].fixed_reg != self.cfg.liveness[self.cfg.g[node].interval].reg {
                    let fixed_reg = self.cfg.g[node].fixed_reg.unwrap() as u8;
                    if let Some(reg) = self.cfg.liveness[self.cfg.g[node].interval].reg {
                        self.gen_mov_reg_reg(self.cfg.g[node].ty, fixed_reg, reg as u8);
                    } else {
                        let mem = self.cfg.liveness[self.cfg.g[node].interval].mem;
                        self.gen_mov_stack_reg(self.cfg.g[node].ty, fixed_reg, mem);
                    }
                }
                // Restore active registers
                for i in saved_intervals {
                    self.restore_interval(i);
                }
                // Clear stack args
                let stack_args_count = stack_args.len();
                if stack_args_count > 0 {
                    dynasm!(self.ops; add rsp, DWORD (stack_args_count << 3) as i32);
                }
            }
            Op::Branch => {
                let cond = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let true_target = self.get_successor_label(0);
                let false_target = self.get_successor_label(1);
                let next_block = self.current_block_id + 1;
                let succ = &self.cfg.blocks[self.current_block_id].succs;
                if succ[0] == next_block {
                    // true block is the next block
                    dynasm! { self.ops
                        ; cmp Rb(cond), BYTE 0
                        ; je => false_target
                    };
                } else if succ[1] == next_block {
                    // false block is the next block
                    dynasm! { self.ops
                        ; cmp Rb(cond), BYTE 0
                        ; jne => true_target
                    };
                } else {
                    unreachable!()
                }
            }
            Op::Jump => {
                let target = self.get_successor_label(0);
                if self.get_successor_id(0) == self.current_block_id + 1 {
                    // the target block is the next block, do nothing
                } else {
                    // the target block is NOT the next block, jump to that block
                    dynasm! { self.ops
                        ; jmp => target
                    };
                }
            }
            Op::BrTable => {
                let index = self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                let default_use_index = self.cfg.g[node].control_uses.len() - 1;
                let default_target = self.get_successor_label(default_use_index);
                if default_use_index > 0 {
                    // default case check
                    dynasm! { self.ops
                        ; cmp Rd(index), DWORD default_use_index as i32
                        ; jae => default_target
                    };
                    // jump to a specific jump-table entry
                    dynasm! { self.ops
                        ; lea Rq(TMP0), [Rd(index) + Rd(index) * 4]
                        ; lea Rq(TMP1), [>jump_table]
                        ; add Rq(TMP1), Rq(TMP0)
                        ; jmp Rq(TMP1)
                        ; jump_table:
                    };
                    for i in 0..default_use_index {
                        let target = self.get_successor_label(i);
                        dynasm!(self.ops; jmp => target);
                    }
                } else {
                    // default-case only
                    dynasm!(self.ops; jmp => default_target);
                }
            }
            Op::Return => {
                if self.cfg.g[node].inputs.len() > 0 {
                    debug_assert_eq!(self.cfg.g[node].inputs.len(), 1);
                    self.load_input_reg(self.cfg.g[node].inputs[0], TMP0);
                }
                self.gen_epilogue()
            }
            Op::DebugBreak => dynasm!(self.ops; int3),
            _ => unimplemented!("{:?}", node),
        }
        if op != Op::Call
            && op != Op::CallIndirect
            && op != Op::Move
            && op != Op::Phi
            && op != Op::EffectPhi
        {
            self.update_spilled_values(node)
        }
    }

    pub fn gen(mut self) -> Arc<dyn CompiledCode> {
        // code
        for _ in 0..self.cfg.blocks.len() {
            self.labels.push(self.ops.new_dynamic_label());
        }
        for i in 0..self.cfg.blocks.len() {
            self.current_block_id = self.cfg.blocks[i].id;
            let label = self.labels[self.cfg.blocks[i].id];
            dynasm! { self.ops
                ; => label
            };
            self.gen_node(self.cfg.blocks[i].label.cast());
            for j in 0..self.cfg.blocks[i].nodes.len() {
                self.gen_node(self.cfg.blocks[i].nodes[j]);
            }
            self.gen_node(self.cfg.blocks[i].terminal.cast());
        }
        // constants
        for (constant, label) in std::mem::take(&mut self.constants) {
            match constant {
                Const::I128(v) => {
                    dynasm! {self.ops
                    ; .align 16
                    ; => label
                    ; .bytes v.to_le_bytes()
                    };
                }
                Const::F32(v) => {
                    dynasm! {self.ops
                    ; .align 8
                    ; => label
                    ; .bytes v.to_le_bytes()
                    };
                }
                Const::F64(v) => {
                    dynasm! {self.ops
                    ; .align 16
                    ; => label
                    ; .bytes v.to_le_bytes()
                    };
                }
                _ => unreachable!(),
            }
        }
        // finalize
        let buf = self.ops.finalize().unwrap();
        let buf = self.compiler.code.alloc_code_buffer::<X64>(&buf);
        let mut call_sites = HashMap::<usize, Box<dyn CallSite>>::new();
        for (offset, mut call_site) in std::mem::take(&mut self.static_call_sites) {
            call_site.set_start_address(buf.start());
            call_sites.insert(offset, call_site);
        }
        let code = X64CompiledCode::new(self.symbol, self.cfg.signature.clone(), buf, call_sites);
        code.link_lazy_compilation_trampoline(self.compiler.lazy_compilation_trampoline.start());
        code.dump();
        self.compiler.code.register_code_object(code)
    }
}