//! Inst 寄存器契约：def/use 扫描 + 副作用判定（DCE 与 liveness 共用单源）。
//!
//! `def_reg` / `use_regs` / `is_pure` 是 `Inst` 的类型契约方法（`impl Inst` 与 `inst.rs`
//! 中的构造 API 同属一类型），落在 oxide_ir 契约层供 DCE 消费、liveness 复用。
//! 寄存器规则与 VM dispatch handler 行为一致：
//! CALL 隐式写 reg 0、GET_PROP 结果写 a/b 槽、HALT 隐式读 reg 0、None 槽映射 Reg(0)。

use oxide_bytecode::opcode::{OpCode, Slot, SlotSpec};
use smallvec::SmallVec;

use crate::inst::Inst;
use crate::operand::Operand;
use crate::IRFunction;

impl Inst {
    /// 本指令定义的寄存器（None 槽按 Reg(0) 映射；CALL 系含隐式 reg 0）。
    /// 无写入返回 None。
    ///
    /// # 步骤
    /// 表驱动解析：取语义表 def 槽位 → 解出对应操作数槽寄存器；Reg0 恒为常量 0。
    ///
    /// # 边界与前提
    /// - `SlotSpec::Range/SpreadArgs/TemplateExprs/BrandReg` 不可能作 def，返回 None。
    pub fn def_reg(&self) -> Option<u32> {
        match self.op.semantics().def? {
            SlotSpec::Slot(slot) => reg_of(slot_operand(slot, self)),
            SlotSpec::Reg0 => Some(0),
            _ => None,
        }
    }

    /// 本指令读取的寄存器（None 槽按 Reg(0) 映射；HALT 特判 reg 0；TEMPLATE_STR 解析 ext）。
    ///
    /// # 步骤
    /// 按语义表 uses 槽位序逐项解析，序即输出序。
    ///
    /// # 边界与前提
    /// - `Range`：nargs=ext[0]，从指定槽起连续 nargs 个寄存器。
    /// - `SpreadArgs`：ext[1..] 每个字 `& 0x7FFF_FFFF`。
    /// - `TemplateExprs`：ext[1..] 中 `seg>>31==1` 的低 31 位。
    /// - `BrandReg`：ext[0] 非 0 才产生 use。
    /// - `ExtReg`：ext[0] `& 0x7FFF_FFFF`（高位标记的寄存器号）。
    pub fn use_regs(&self) -> SmallVec<[u32; 4]> {
        let mut uses = SmallVec::new();
        for &spec in self.op.semantics().uses {
            match spec {
                SlotSpec::Slot(slot) => push_operand(&mut uses, slot_operand(slot, self)),
                SlotSpec::Reg0 => uses.push(0),
                SlotSpec::Range(slot) => {
                    let nargs = self.ext.first().copied().unwrap_or(0);
                    push_range(&mut uses, reg_of(slot_operand(slot, self)), nargs);
                }
                SlotSpec::SpreadArgs => {
                    for &w in self.ext.iter().skip(1) {
                        uses.push(w & 0x7FFF_FFFF);
                    }
                }
                SlotSpec::TemplateExprs => {
                    for seg in self.ext.iter().skip(1) {
                        if seg >> 31 == 1 {
                            uses.push(seg & 0x7FFF_FFFF);
                        }
                    }
                }
                SlotSpec::BrandReg => {
                    let brand_reg = self.ext.first().copied().unwrap_or(0);
                    if brand_reg != 0 {
                        uses.push(brand_reg);
                    }
                }
                SlotSpec::ExtReg => {
                    let w = self.ext.first().copied().unwrap_or(0);
                    uses.push(w & 0x7FFF_FFFF);
                }
            }
        }
        uses
    }

    /// 本指令是否无观察副作用（LOAD_VAR 的 This+derived 特判需要函数元信息）。
    ///
    /// 纯 = 结果未用时可删。表内 pure 是静态字段，LOAD_VAR 上下文例外在此叠加。
    pub fn is_pure(&self, f: &IRFunction) -> bool {
        let base = self.op.semantics().pure;
        base && !(self.op == OpCode::LOAD_VAR && self.a == Operand::This && f.is_derived_constructor)
    }
}

/// 槽位 → 对应操作数（表解析用；Const/Imm/Label 由 reg_of 过滤）。
fn slot_operand(slot: Slot, i: &Inst) -> &Operand {
    match slot {
        Slot::Rd => &i.rd,
        Slot::A => &i.a,
        Slot::B => &i.b,
    }
}

/// 操作数 → 物理寄存器号。None 槽映射 reg 0（与 lower.rs operand_to_u8 一致）；
/// Const/Imm/Label 不是寄存器槽，返回 None。
fn reg_of(o: &Operand) -> Option<u32> {
    match o {
        Operand::Reg(r) => Some(*r),
        Operand::This => Some(254),
        Operand::NewTarget => Some(255),
        Operand::None => Some(0),
        Operand::Const(_) | Operand::Imm(_) | Operand::Label(_) => None,
    }
}

/// 把寄存器操作数推入 use 集合（非寄存器槽跳过）。
fn push_operand(uses: &mut SmallVec<[u32; 4]>, o: &Operand) {
    if let Some(r) = reg_of(o) {
        uses.push(r);
    }
}

/// 推入连续参数区间 [first, first+nargs)。
fn push_range(uses: &mut SmallVec<[u32; 4]>, first: Option<u32>, nargs: u32) {
    if let Some(f) = first {
        uses.extend((0..nargs).map(|i| f + i));
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::inst::Inst;
    use crate::operand::Operand;
    use crate::IRFunction;

    // ── def_reg / use_regs 契约测试（反直觉槽位断言）──

    #[test]
    fn binary_op_def_rd_use_ab() {
        let inst = Inst::new(OpCode::ADD, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2));
        assert_eq!(inst.def_reg(), Some(0));
        assert_eq!(inst.use_regs().as_slice(), &[1, 2]);
    }

    #[test]
    fn unary_op_def_rd_use_a() {
        let inst = Inst::new(OpCode::NEG, Operand::Reg(0), Operand::Reg(1), Operand::None);
        assert_eq!(inst.def_reg(), Some(0));
        assert_eq!(inst.use_regs().as_slice(), &[1]);
    }

    #[test]
    fn get_prop_def_is_a_slot_not_rd() {
        // GET_PROP rd=obj 是 use，结果写 a 槽
        let inst = Inst::new(OpCode::GET_PROP, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2));
        assert_eq!(inst.def_reg(), Some(1));
        assert_eq!(inst.use_regs().as_slice(), &[0, 2]);
    }

    #[test]
    fn get_prop_dynamic_def_is_b_slot() {
        // GET_PROP_DYNAMIC rd=obj 是 use，结果写 b 槽
        let inst = Inst::new(OpCode::GET_PROP_DYNAMIC, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2));
        assert_eq!(inst.def_reg(), Some(2));
        assert_eq!(inst.use_regs().as_slice(), &[0, 1]);
    }

    #[test]
    fn ic_get_prop_a_slot_is_use_and_def() {
        // IC_GET_PROP a 槽既是对象 use 又是结果 def
        let inst = Inst::ic_get(Operand::Reg(1), Operand::Reg(2));
        assert_eq!(inst.def_reg(), Some(1));
        let uses = inst.use_regs();
        assert_eq!(uses.as_slice(), &[1, 2]);
    }

    #[test]
    fn call_def_is_implicit_reg0_with_arg_range() {
        // CALL rd=callee 是 use，结果隐式写 reg 0；参数 b..b+nargs 连续
        let inst = Inst::call(Operand::Reg(0), Operand::Reg(1), Operand::Reg(2), 3);
        assert_eq!(inst.def_reg(), Some(0));
        assert_eq!(inst.use_regs().as_slice(), &[0, 1, 2, 3, 4]);
    }

    #[test]
    fn call_native_def_is_implicit_reg0() {
        let inst = Inst::call_native(Operand::Reg(0), Operand::Reg(1), Operand::Reg(2), 1);
        assert_eq!(inst.def_reg(), Some(0));
        assert_eq!(inst.use_regs().as_slice(), &[0, 1, 2]);
    }

    #[test]
    fn new_expression_uses_ctor_and_arg_range() {
        let inst = Inst::new_expression(Operand::Reg(3), Operand::Reg(0), Operand::Reg(1), 2);
        assert_eq!(inst.def_reg(), Some(3));
        assert_eq!(inst.use_regs().as_slice(), &[0, 1, 2]);
    }

    #[test]
    fn super_call_uses_arg_range() {
        let inst = Inst::super_call(Operand::Reg(3), Operand::Reg(1), 1);
        assert_eq!(inst.def_reg(), Some(3));
        assert_eq!(inst.use_regs().as_slice(), &[1]);
    }

    #[test]
    fn halt_implicitly_uses_reg0() {
        // HALT 返回 regs[0]，顶层 LOAD_VAR(None, r) 链靠它保活
        let inst = Inst::new(OpCode::HALT, Operand::None, Operand::None, Operand::None);
        assert_eq!(inst.def_reg(), None);
        assert_eq!(inst.use_regs().as_slice(), &[0]);
    }

    #[test]
    fn spread_call_def_and_uses() {
        // CALL_SPREAD：结果隐式写 reg 0；use = callee + this + ext 有序实参字（静态/spread 同编）
        let call = Inst::call_spread(Operand::Reg(0), Operand::Reg(1), &[5, 0x8000_0000 | 9, 300]);
        assert_eq!(call.def_reg(), Some(0));
        assert_eq!(call.use_regs().as_slice(), &[0, 1, 5, 9, 300]);

        // NEW_EXPRESSION_SPREAD：rd 即 def；use = ctor + 实参字
        let ne = Inst::new_expression_spread(Operand::Reg(3), Operand::Reg(0), &[7, 0x8000_0000 | 12]);
        assert_eq!(ne.def_reg(), Some(3));
        assert_eq!(ne.use_regs().as_slice(), &[0, 7, 12]);

        // SUPER_CALL_SPREAD：无 callee/this 槽
        let sc = Inst::super_call_spread(Operand::Reg(3), &[4, 0x8000_0000 | 8]);
        assert_eq!(sc.def_reg(), Some(3));
        assert_eq!(sc.use_regs().as_slice(), &[4, 8]);
    }

    #[test]
    fn void_defs_rd_no_use() {
        // VM 的 VOID handler 不读 a 槽
        let inst = Inst::new(OpCode::VOID, Operand::Reg(1), Operand::Reg(2), Operand::None);
        assert_eq!(inst.def_reg(), Some(1));
        assert!(inst.use_regs().is_empty());
    }

    #[test]
    fn load_const_create_closure_load_upvalue_no_use() {
        // a 槽是 Const/Imm 立即数，非寄存器
        let lc = Inst::load_const(Operand::Reg(1), 5);
        assert_eq!(lc.def_reg(), Some(1));
        assert!(lc.use_regs().is_empty());

        let cc = Inst::create_closure(Operand::Reg(1), 0);
        assert_eq!(cc.def_reg(), Some(1));
        assert!(cc.use_regs().is_empty());

        let lu = Inst::new(OpCode::LOAD_UPVALUE, Operand::Reg(1), Operand::Imm(0), Operand::None);
        assert_eq!(lu.def_reg(), Some(1));
        assert!(lu.use_regs().is_empty());
    }

    #[test]
    fn none_slot_maps_to_reg0() {
        // None 槽与 lower.rs operand_to_u8 一致，统一映射物理 reg 0
        let lv = Inst::new(OpCode::LOAD_VAR, Operand::Reg(1), Operand::None, Operand::None);
        assert_eq!(lv.use_regs().as_slice(), &[0]);

        let cg = Inst::new(OpCode::CELL_GET, Operand::Reg(0), Operand::None, Operand::Imm(0));
        assert_eq!(cg.use_regs().as_slice(), &[0]);
    }

    #[test]
    fn template_str_parses_expr_regs_from_ext() {
        // ext[0] 跳过；表达式段在 RegAlloc 前保留完整 u32 vreg。
        let with_expr = Inst::template_str(Operand::Reg(1), 2, 10, &[0x1234, 0x8000_0000 | 300]);
        assert_eq!(with_expr.use_regs().as_slice(), &[300]);

        // 纯 quasi（无表达式）：不误报寄存器
        let no_expr = Inst::template_str(Operand::Reg(1), 1, 10, &[0x1234]);
        assert!(no_expr.use_regs().is_empty());
    }

    #[test]
    fn jmp_if_false_uses_cond_reg() {
        let inst = Inst::jmp_if_false(3, 9);
        assert_eq!(inst.def_reg(), None);
        assert_eq!(inst.use_regs().as_slice(), &[3]);
    }

    #[test]
    fn jmp_and_try_no_use() {
        assert!(Inst::jmp(9).use_regs().is_empty());
        assert!(Inst::try_begin(9).use_regs().is_empty());
        assert!(Inst::try_finally_begin(9).use_regs().is_empty());
    }

    #[test]
    fn make_cell_no_def_uses_rd() {
        let inst = Inst::new(OpCode::MAKE_CELL, Operand::Reg(5), Operand::None, Operand::None);
        assert_eq!(inst.def_reg(), None);
        assert_eq!(inst.use_regs().as_slice(), &[5]);
    }

    #[test]
    fn cell_set_and_store_upvalue_use_a_no_def() {
        let cs = Inst::new(OpCode::CELL_SET, Operand::None, Operand::Reg(1), Operand::Imm(0));
        assert_eq!(cs.def_reg(), None);
        assert_eq!(cs.use_regs().as_slice(), &[1]);

        let su = Inst::new(OpCode::STORE_UPVALUE, Operand::None, Operand::Reg(1), Operand::Imm(0));
        assert_eq!(su.def_reg(), None);
        assert_eq!(su.use_regs().as_slice(), &[1]);
    }

    #[test]
    fn return_throw_use_rd_with_none_mapping_reg0() {
        let ret = Inst::new(OpCode::RETURN, Operand::None, Operand::None, Operand::None);
        assert_eq!(ret.def_reg(), None);
        assert_eq!(ret.use_regs().as_slice(), &[0]);

        let thr = Inst::new(OpCode::THROW, Operand::Reg(2), Operand::None, Operand::None);
        assert_eq!(thr.def_reg(), None);
        assert_eq!(thr.use_regs().as_slice(), &[2]);
    }

    #[test]
    fn rest_object_uses_a() {
        let inst = Inst::rest_object(Operand::Reg(0), Operand::Reg(1), 7, None);
        assert_eq!(inst.def_reg(), Some(0));
        // b 槽 None 映射 reg 0（excl_arr 缺省），REST_OBJECT 运行时同时读源与排除键。
        assert_eq!(inst.use_regs().as_slice(), &[1, 0]);
    }

    #[test]
    fn spread_object_def_rd_uses_rd_and_a() {
        // SPREAD_OBJECT 原地改目标对象：def=rd，use=[rd, a]，不可删除（有观察副作用）
        let inst = Inst::spread_object(Operand::Reg(3), Operand::Reg(7));
        assert_eq!(inst.def_reg(), Some(3));
        assert_eq!(inst.use_regs().as_slice(), &[3, 7]);
        let f = IRFunction::new();
        assert!(!inst.is_pure(&f));
    }

    #[test]
    fn create_arguments_defs_rd_no_register_use_impure() {
        // CREATE_ARGUMENTS 写 rd；实参从 spill 栈读取，无寄存器 use；
        // 创建对象有观察副作用（分配的 arguments 可被外部观察到），不可删除。
        let inst = Inst::create_arguments(Operand::Reg(6));
        assert_eq!(inst.def_reg(), Some(6));
        assert!(inst.use_regs().is_empty());
        let f = IRFunction::new();
        assert!(!inst.is_pure(&f));
    }

    #[test]
    fn for_in_next_defs_rd_no_use() {
        let inst = Inst::new(OpCode::FOR_IN_NEXT, Operand::Reg(0), Operand::None, Operand::None);
        assert_eq!(inst.def_reg(), Some(0));
        assert!(inst.use_regs().is_empty());
    }

    #[test]
    fn store_var_def_rd_use_a() {
        let inst = Inst::new(OpCode::STORE_VAR, Operand::Reg(0), Operand::Reg(1), Operand::None);
        assert_eq!(inst.def_reg(), Some(0));
        assert_eq!(inst.use_regs().as_slice(), &[1]);
    }

    #[test]
    fn regalloc_opcodes_def_use_contract() {
        let mov = Inst::inst_mov(Operand::Reg(3), Operand::Reg(7));
        assert_eq!(mov.def_reg(), Some(3));
        assert_eq!(mov.use_regs().as_slice(), &[7]);

        let spill = Inst::inst_spill(Operand::Reg(5), 42);
        assert_eq!(spill.def_reg(), None);
        assert_eq!(spill.use_regs().as_slice(), &[5]);

        let unspill = Inst::inst_unspill(Operand::Reg(9), 42);
        assert_eq!(unspill.def_reg(), Some(9));
        assert!(unspill.use_regs().is_empty());
    }

    // ── is_pure 契约测试（纯/非纯族代表 opcode）──

    #[test]
    fn pure_ops_are_deletable() {
        let f = IRFunction::new();
        // 算术 / 比较 / 位 / 逻辑
        assert!(Inst::new(OpCode::ADD, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(Inst::new(OpCode::SUB, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(Inst::new(OpCode::MUL, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(Inst::new(OpCode::NEG, Operand::Reg(0), Operand::Reg(1), Operand::None).is_pure(&f));
        assert!(Inst::new(OpCode::EQ, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(Inst::new(OpCode::STRICT_EQ, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(Inst::new(OpCode::LT, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(Inst::new(OpCode::BIT_AND, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(Inst::new(OpCode::BIT_NOT, Operand::Reg(0), Operand::Reg(1), Operand::None).is_pure(&f));
        assert!(Inst::new(OpCode::AND, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(Inst::new(OpCode::OR, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(Inst::new(OpCode::NOT, Operand::Reg(0), Operand::Reg(1), Operand::None).is_pure(&f));
        assert!(Inst::new(OpCode::NULLISH, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        // 分配/常量/空操作
        assert!(Inst::new(OpCode::NOP, Operand::None, Operand::None, Operand::None).is_pure(&f));
        assert!(Inst::load_const(Operand::Reg(1), 0).is_pure(&f));
        assert!(Inst::new(OpCode::VOID, Operand::Reg(1), Operand::None, Operand::None).is_pure(&f));
        assert!(Inst::new(OpCode::TYPEOF, Operand::Reg(1), Operand::Reg(2), Operand::None).is_pure(&f));
        assert!(Inst::new(OpCode::NEW_OBJECT, Operand::Reg(1), Operand::None, Operand::None).is_pure(&f));
        assert!(Inst::new(OpCode::NEW_ARRAY, Operand::Reg(1), Operand::None, Operand::None).is_pure(&f));
        // 闭包/单元读取
        assert!(Inst::create_closure(Operand::Reg(1), 0).is_pure(&f));
        assert!(Inst::new(OpCode::LOAD_UPVALUE, Operand::Reg(1), Operand::Imm(0), Operand::None).is_pure(&f));
        assert!(Inst::new(OpCode::CELL_GET, Operand::Reg(0), Operand::Reg(1), Operand::Imm(0)).is_pure(&f));
        // 模板字符串
        assert!(Inst::template_str(Operand::Reg(1), 1, 10, &[0x1234]).is_pure(&f));
        // RegAlloc 辅助：MOV 纯
        assert!(Inst::inst_mov(Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        // LOAD_VAR 普通（a=Reg）纯
        assert!(Inst::new(OpCode::LOAD_VAR, Operand::Reg(1), Operand::Reg(2), Operand::None).is_pure(&f));
        // STORE_VAR 一律有副作用（顶层变量赋值全局可观察，不删）
        assert!(!Inst::new(OpCode::STORE_VAR, Operand::Reg(0), Operand::Reg(1), Operand::None).is_pure(&f));
        assert!(!Inst::new(OpCode::STORE_VAR, Operand::Reg(0), Operand::Reg(1), Operand::Imm(0)).is_pure(&f));
        assert!(!Inst::new(OpCode::STORE_VAR, Operand::Reg(0), Operand::Reg(1), Operand::Imm(1)).is_pure(&f));
    }

    #[test]
    fn impure_ops_are_not_deletable() {
        let f = IRFunction::new();
        // getter / 写对象属性
        assert!(!Inst::ic_get(Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::GET_PROP, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::GET_PROP_DYNAMIC, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::ic_set(Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::SET_PROP, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::SUPER_GET_PROP, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::DEFINE_ACCESSOR, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::DEFINE_ACCESSOR_DYNAMIC, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::DELETE_PROP_STATIC, Operand::Reg(0), Operand::Reg(0), Operand::None).is_pure(&f));
        assert!(!Inst::new(OpCode::DELETE_PROP_DYNAMIC, Operand::Reg(0), Operand::None, Operand::Reg(2)).is_pure(&f));
        // 调用 / 异常 / 控制流
        assert!(!Inst::call(Operand::Reg(0), Operand::Reg(1), Operand::Reg(2), 0).is_pure(&f));
        assert!(!Inst::call_native(Operand::Reg(0), Operand::Reg(1), Operand::Reg(2), 0).is_pure(&f));
        assert!(!Inst::new_expression(Operand::Reg(3), Operand::Reg(0), Operand::Reg(1), 0).is_pure(&f));
        assert!(!Inst::super_call(Operand::Reg(3), Operand::Reg(1), 0).is_pure(&f));
        assert!(!Inst::call_spread(Operand::Reg(0), Operand::Reg(1), &[3]).is_pure(&f));
        assert!(!Inst::new_expression_spread(Operand::Reg(3), Operand::Reg(0), &[2]).is_pure(&f));
        assert!(!Inst::super_call_spread(Operand::Reg(3), &[2]).is_pure(&f));
        assert!(!Inst::new(OpCode::CREATE_REGEXP, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::RETURN, Operand::None, Operand::None, Operand::None).is_pure(&f));
        assert!(!Inst::new(OpCode::THROW, Operand::Reg(2), Operand::None, Operand::None).is_pure(&f));
        assert!(!Inst::new(OpCode::HALT, Operand::None, Operand::None, Operand::None).is_pure(&f));
        assert!(!Inst::jmp(9).is_pure(&f));
        assert!(!Inst::jmp_if_false(3, 9).is_pure(&f));
        assert!(!Inst::try_begin(9).is_pure(&f));
        assert!(!Inst::try_finally_begin(9).is_pure(&f));
        // 迭代器 / 复合更新 / 写共享状态
        assert!(!Inst::new(OpCode::FOR_IN_NEXT, Operand::Reg(0), Operand::None, Operand::None).is_pure(&f));
        assert!(!Inst::new(OpCode::FOR_OF_NEXT, Operand::Reg(0), Operand::None, Operand::None).is_pure(&f));
        assert!(!Inst::new(OpCode::INC_PRE, Operand::Reg(0), Operand::Reg(0), Operand::None).is_pure(&f));
        assert!(!Inst::new(OpCode::COMPOUND_ADD, Operand::Reg(0), Operand::Reg(1), Operand::None).is_pure(&f));
        assert!(!Inst::new(OpCode::MEMBER_INC, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::COMPOUND_MEMBER_ADD, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::rest_object(Operand::Reg(0), Operand::Reg(1), 7, None).is_pure(&f));
        assert!(!Inst::new(OpCode::INSTANCEOF, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::IN, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::GET_PRIVATE, Operand::Reg(0), Operand::Reg(1), Operand::Reg(2)).is_pure(&f));
        assert!(!Inst::new(OpCode::SET_HOME_OBJECT, Operand::Reg(0), Operand::Reg(1), Operand::None).is_pure(&f));
        assert!(!Inst::new(OpCode::STORE_UPVALUE, Operand::None, Operand::Reg(1), Operand::Imm(0)).is_pure(&f));
        assert!(!Inst::new(OpCode::CELL_SET, Operand::None, Operand::Reg(1), Operand::Imm(0)).is_pure(&f));
        assert!(!Inst::new(OpCode::MAKE_CELL, Operand::Reg(5), Operand::None, Operand::None).is_pure(&f));
        // RegAlloc 辅助：SPILL/UNSPILL 有副作用（删 SPILL 后 UNSPILL 读陈旧值）
        assert!(!Inst::inst_spill(Operand::Reg(5), 42).is_pure(&f));
        assert!(!Inst::inst_unspill(Operand::Reg(9), 42).is_pure(&f));
        // 占位 opcode 防御性有副作用
        assert!(!Inst::new(OpCode::SWITCH_TABLE, Operand::None, Operand::None, Operand::None).is_pure(&f));
    }

    #[test]
    fn store_var_all_branches_are_impure() {
        // STORE_VAR 写目标变量寄存器，顶层/模块作用域变量全局可观察，一律不删
        // （const guard 抛错、普通 var/let 赋值都可能改变外部观察状态）
        let f = IRFunction::new();
        assert!(!Inst::new(OpCode::STORE_VAR, Operand::Reg(0), Operand::Reg(1), Operand::None).is_pure(&f));
        assert!(!Inst::new(OpCode::STORE_VAR, Operand::Reg(0), Operand::Reg(1), Operand::Imm(0)).is_pure(&f));
        assert!(!Inst::new(OpCode::STORE_VAR, Operand::Reg(0), Operand::Reg(1), Operand::Imm(1)).is_pure(&f));
    }

    #[test]
    fn load_var_this_derived_constructor_special_case() {
        // a==This + is_derived_constructor 时读 this 可能抛 ReferenceError，不可删
        let mut derived = IRFunction::new();
        derived.is_derived_constructor = true;
        let non_derived = IRFunction::new();

        let this_load = Inst::new(OpCode::LOAD_VAR, Operand::Reg(1), Operand::This, Operand::None);
        assert!(!this_load.is_pure(&derived));
        assert!(this_load.is_pure(&non_derived));

        // a=Reg 普通 LOAD_VAR 在 derived 函数中也纯
        let reg_load = Inst::new(OpCode::LOAD_VAR, Operand::Reg(1), Operand::Reg(2), Operand::None);
        assert!(reg_load.is_pure(&derived));
    }

    // ── 表驱动解析 vs 老 match 的一致性（Phase B1 迁移校验）──

    /// 每个 opcode 构造一条规范指令：rd/a/b 置 Reg(1/2/3)，ext 按族填真实布局。
    fn canonical_inst(op: OpCode) -> Inst {
        match op {
            OpCode::CALL | OpCode::CALL_NATIVE => {
                Inst::call(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3), 2)
            }
            OpCode::NEW_EXPRESSION => {
                Inst::new_expression(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3), 2)
            }
            OpCode::SUPER_CALL => Inst::super_call(Operand::Reg(1), Operand::Reg(2), 2),
            OpCode::CALL_SPREAD => {
                Inst::call_spread(Operand::Reg(1), Operand::Reg(2), &[5, 0x8000_0000 | 9])
            }
            OpCode::NEW_EXPRESSION_SPREAD => {
                Inst::new_expression_spread(Operand::Reg(1), Operand::Reg(2), &[5, 0x8000_0000 | 9])
            }
            OpCode::SUPER_CALL_SPREAD => {
                Inst::super_call_spread(Operand::Reg(1), &[5, 0x8000_0000 | 9])
            }
            OpCode::IC_GET_PROP => Inst::ic_get(Operand::Reg(1), Operand::Reg(2)),
            OpCode::IC_SET_PROP => Inst::ic_set(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3)),
            OpCode::MEMBER_INC => {
                Inst::member_inc(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::MEMBER_DEC => {
                Inst::member_dec(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_ADD => {
                Inst::compound_member_add(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_SUB => {
                Inst::compound_member_sub(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_MUL => {
                Inst::compound_member_mul(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_DIV => {
                Inst::compound_member_div(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_MOD => {
                Inst::compound_member_mod(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_EXP => {
                Inst::compound_member_exp(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_BIT_AND => {
                Inst::compound_member_bit_and(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_BIT_OR => {
                Inst::compound_member_bit_or(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_BIT_XOR => {
                Inst::compound_member_bit_xor(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_SHL => {
                Inst::compound_member_shl(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_SHR => {
                Inst::compound_member_shr(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::COMPOUND_MEMBER_USHR => {
                Inst::compound_member_ushr(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3))
            }
            OpCode::TEMPLATE_STR => Inst::template_str(Operand::Reg(1), 2, 10, &[0x1234, 0x8000_0000 | 5]),
            OpCode::GET_PRIVATE => {
                Inst::get_private(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3), 7, 99)
            }
            OpCode::SET_PRIVATE => {
                Inst::set_private(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3), 7, 99)
            }
            OpCode::INIT_PRIVATE => {
                Inst::init_private(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3), true)
            }
            OpCode::PRIVATE_BRAND_IN => {
                Inst::private_brand_in(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3), 7, 99)
            }
            OpCode::SPILL => Inst::inst_spill(Operand::Reg(1), 42),
            OpCode::UNSPILL => Inst::inst_unspill(Operand::Reg(1), 42),
            OpCode::REST_OBJECT => Inst::rest_object(Operand::Reg(1), Operand::Reg(2), 7, None),
            OpCode::DEFINE_ACCESSOR => {
                Inst::define_accessor(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3), 42)
            }
            OpCode::DEFINE_ACCESSOR_DYNAMIC => {
                Inst::define_accessor_dynamic(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3), 7)
            }
            OpCode::DELETE_PROP_STATIC => Inst::delete_prop_static(Operand::Reg(1), 9),
            _ => Inst::new(op, Operand::Reg(1), Operand::Reg(2), Operand::Reg(3)),
        }
    }

    /// 全 opcode 表遍历断言（golden）：def/use/pure 与表逐项一致。
    fn assert_contract(op: OpCode, def: Option<u32>, uses: &[u32], pure: bool) {
        let inst = canonical_inst(op);
        let f = IRFunction::new();
        assert_eq!(inst.def_reg(), def, "{op}: def");
        assert_eq!(inst.use_regs().as_slice(), uses, "{op}: uses");
        assert_eq!(inst.is_pure(&f), pure, "{op}: pure");
    }

    /// 同一规格的多个 opcode 批量断言。
    fn assert_group(ops: &[OpCode], def: Option<u32>, uses: &[u32], pure: bool) {
        for &op in ops {
            assert_contract(op, def, uses, pure);
        }
    }

    /// 每个 opcode 的 def/use/pure 与现有语义表一致（canonical rd=1, a=2, b=3）。
    #[test]
    fn opcode_semantics_golden_table() {
        // 二元运算：def=rd, uses=[a,b]，纯
        assert_group(
            &[
                OpCode::ADD,
                OpCode::SUB,
                OpCode::MUL,
                OpCode::DIV,
                OpCode::MOD,
                OpCode::EQ,
                OpCode::NEQ,
                OpCode::LT,
                OpCode::GT,
                OpCode::LTE,
                OpCode::GTE,
                OpCode::AND,
                OpCode::OR,
                OpCode::STRICT_EQ,
                OpCode::STRICT_NEQ,
                OpCode::BIT_AND,
                OpCode::BIT_OR,
                OpCode::BIT_XOR,
                OpCode::SHL,
                OpCode::SHR,
                OpCode::USHR,
                OpCode::NULLISH,
            ],
            Some(1),
            &[2, 3],
            true,
        );
        // 二元但不可删：coerce 有观察路径
        assert_group(&[OpCode::IN, OpCode::INSTANCEOF, OpCode::CREATE_REGEXP], Some(1), &[2, 3], false);
        // 一元：def=rd, uses=[a]
        assert_group(
            &[OpCode::NEG, OpCode::NOT, OpCode::UNARY_PLUS, OpCode::BIT_NOT, OpCode::TYPEOF],
            Some(1),
            &[2],
            true,
        );
        // 复合赋值：def=rd, uses=[rd,a]，不可删
        assert_group(
            &[
                OpCode::COMPOUND_ADD,
                OpCode::COMPOUND_SUB,
                OpCode::COMPOUND_MUL,
                OpCode::COMPOUND_DIV,
                OpCode::COMPOUND_MOD,
                OpCode::COMPOUND_EXP,
                OpCode::COMPOUND_AND,
                OpCode::COMPOUND_OR,
                OpCode::COMPOUND_XOR,
                OpCode::COMPOUND_SHL,
                OpCode::COMPOUND_SHR,
                OpCode::COMPOUND_USHR,
            ],
            Some(1),
            &[1, 2],
            false,
        );
        // RegAlloc 辅助
        assert_contract(OpCode::MOV, Some(1), &[2], true);
        assert_contract(OpCode::SPILL, None, &[1], false);
        assert_contract(OpCode::UNSPILL, Some(1), &[], false);
        assert_contract(OpCode::SPREAD_OBJECT, Some(1), &[1, 2], false);
        // 无条件跳转 / try 标记 / 生成器 body 标记：无 def 无 use
        assert_group(
            &[
                OpCode::BREAK,
                OpCode::CONTINUE,
                OpCode::JMP,
                OpCode::TRY_BEGIN,
                OpCode::TRY_END,
                OpCode::TRY_FINALLY_BEGIN,
                OpCode::TRY_FINALLY_END,
                OpCode::FOR_IN_CLEANUP,
                OpCode::FOR_OF_CLOSE,
                OpCode::SUSPEND_BODY,
            ],
            None,
            &[],
            false,
        );
        // 条件跳转：uses=[rd]
        assert_group(&[OpCode::JMP_IF_FALSE, OpCode::JMP_IF_TRUE, OpCode::JMP_IF_NULLISH], None, &[1], false);
        // 迭代器 INIT 读 a；NEXT/DONE 无 use 写 rd
        assert_group(&[OpCode::FOR_OF_INIT, OpCode::FOR_IN_INIT, OpCode::FOR_AWAIT_OF_INIT], None, &[2], false);
        assert_group(
            &[
                OpCode::FOR_OF_NEXT,
                OpCode::FOR_IN_NEXT,
                OpCode::FOR_IN_DONE,
                OpCode::FOR_OF_DONE,
                OpCode::FOR_AWAIT_OF_NEXT,
            ],
            Some(1),
            &[],
            false,
        );
        assert_contract(OpCode::FOR_AWAIT_OF_DONE, Some(1), &[2], false);
        // 自增/自减：def=rd, uses=[rd]
        assert_group(&[OpCode::INC_PRE, OpCode::INC_POST, OpCode::DEC_PRE, OpCode::DEC_POST], Some(1), &[1], false);
        // 占位 opcode：def=rd 保守，不可删
        assert_group(
            &[
                OpCode::SWITCH_TABLE,
                OpCode::PROFILE_SHAPE,
                OpCode::PROFILE_BRANCH,
                OpCode::PROFILE_CALL,
                OpCode::FORK,
                OpCode::JOIN,
            ],
            Some(1),
            &[],
            false,
        );
        // 异常 / 返回 / 停机
        assert_contract(OpCode::THROW, None, &[1], false);
        assert_contract(OpCode::RETURN, None, &[1], false);
        assert_contract(OpCode::HALT, None, &[0], false);
        // 模板字符串：表达式寄存器来自 ext
        assert_contract(OpCode::TEMPLATE_STR, Some(1), &[5], true);
        // 小语言特性
        assert_contract(OpCode::DELETE_PROP_STATIC, None, &[1], false);
        assert_contract(OpCode::DELETE_PROP_DYNAMIC, None, &[1, 3], false);
        assert_contract(OpCode::MAKE_CELL, None, &[1], false);
        assert_contract(OpCode::MAKE_CELL_FRESH, None, &[1], false);
        assert_contract(OpCode::CELL_SET, None, &[2], false);
        assert_contract(OpCode::CELL_GET, Some(1), &[2], true);
        assert_contract(OpCode::REST_OBJECT, Some(1), &[2, 0], false);
        // 变量加载族
        assert_contract(OpCode::LOAD_VAR, Some(1), &[2], true);
        assert_contract(OpCode::STORE_VAR, Some(1), &[2], false);
        assert_contract(OpCode::LOAD_CONST, Some(1), &[], true);
        assert_contract(OpCode::LOAD_UPVALUE, Some(1), &[], true);
        assert_contract(OpCode::CREATE_CLOSURE, Some(1), &[], true);
        assert_contract(OpCode::STORE_UPVALUE, None, &[2], false);
        // 调用族：CALL 系隐式写 reg 0
        assert_contract(OpCode::CALL, Some(0), &[1, 2, 3, 4], false);
        assert_contract(OpCode::CALL_NATIVE, Some(0), &[1, 2, 3, 4], false);
        assert_contract(OpCode::NEW_EXPRESSION, Some(1), &[2, 3, 4], false);
        assert_contract(OpCode::SUPER_CALL, Some(1), &[2, 3], false);
        assert_contract(OpCode::CALL_SPREAD, Some(0), &[1, 2, 5, 9], false);
        assert_contract(OpCode::NEW_EXPRESSION_SPREAD, Some(1), &[2, 5, 9], false);
        assert_contract(OpCode::SUPER_CALL_SPREAD, Some(1), &[5, 9], false);
        // super 属性读 / home object / accessor
        assert_group(&[OpCode::SUPER_GET_PROP, OpCode::SUPER_STATIC_GET_PROP], Some(1), &[2, 3], false);
        assert_contract(OpCode::SET_HOME_OBJECT, None, &[1, 2], false);
        assert_contract(OpCode::DEFINE_ACCESSOR, None, &[1, 2, 3], false);
        assert_contract(OpCode::DEFINE_ACCESSOR_DYNAMIC, None, &[1, 2, 3, 7], false);
        // Object Property：GET_PROP 写 a 槽、DYNAMIC 写 b 槽
        assert_contract(OpCode::GET_PROP, Some(2), &[1, 3], false);
        assert_contract(OpCode::GET_PROP_DYNAMIC, Some(3), &[1, 2], false);
        assert_contract(OpCode::IC_GET_PROP, Some(1), &[1, 2], false);
        assert_contract(OpCode::SET_PROP, None, &[1, 2, 3], false);
        assert_contract(OpCode::SET_PROP_DYNAMIC, None, &[1, 2, 3], false);
        assert_contract(OpCode::IC_SET_PROP, None, &[1, 2, 3], false);
        assert_contract(OpCode::SET_ELEM, None, &[1, 2, 3], false);
        assert_group(&[OpCode::NEW_OBJECT, OpCode::NEW_ARRAY], Some(1), &[], true);
        // define 语义属性写入 / arguments / rest
        assert_group(&[OpCode::DEFINE_PROP, OpCode::DEFINE_GLOBAL_PROP], None, &[1, 2, 3], false);
        assert_group(&[OpCode::CREATE_ARGUMENTS, OpCode::CREATE_REST_ARRAY], Some(1), &[], false);
        // 成员更新：val 槽原地写（a/b 槽）
        assert_group(&[OpCode::MEMBER_INC, OpCode::MEMBER_DEC], Some(2), &[1, 3], false);
        assert_group(&[OpCode::DYN_MEMBER_INC, OpCode::DYN_MEMBER_DEC], Some(3), &[1, 2], false);
        assert_group(
            &[
                OpCode::COMPOUND_MEMBER_ADD,
                OpCode::COMPOUND_MEMBER_SUB,
                OpCode::COMPOUND_MEMBER_MUL,
                OpCode::COMPOUND_MEMBER_DIV,
                OpCode::COMPOUND_MEMBER_MOD,
                OpCode::COMPOUND_MEMBER_EXP,
                OpCode::COMPOUND_MEMBER_BIT_AND,
                OpCode::COMPOUND_MEMBER_BIT_OR,
                OpCode::COMPOUND_MEMBER_BIT_XOR,
                OpCode::COMPOUND_MEMBER_SHL,
                OpCode::COMPOUND_MEMBER_SHR,
                OpCode::COMPOUND_MEMBER_USHR,
            ],
            Some(2),
            &[1, 2, 3],
            false,
        );
        // 私有成员：brand_reg 非 0 时产生额外 use
        assert_contract(OpCode::GET_PRIVATE, Some(1), &[2, 3, 7], false);
        assert_contract(OpCode::SET_PRIVATE, None, &[1, 2, 3, 7], false);
        assert_contract(OpCode::INIT_PRIVATE, None, &[1, 2, 3], false);
        assert_contract(OpCode::PRIVATE_BRAND_IN, Some(1), &[2, 3], false);
        // 生成器 / 异步：恢复值经 reg 0
        assert_group(&[OpCode::YIELD, OpCode::YIELD_STAR, OpCode::AWAIT], Some(0), &[1], false);
        assert_contract(OpCode::FOR_AWAIT_OF_CLOSE, None, &[], false);
        // 位 / 对象 / 杂项
        assert_contract(OpCode::TO_OBJECT, Some(1), &[1], false);
        // NOP：rd=None 时 def_reg 仍为 Some(0)（catch-all 语义，表内保持 def=Rd）
        assert_eq!(Inst::new(OpCode::NOP, Operand::None, Operand::None, Operand::None).def_reg(), Some(0));
        assert_contract(OpCode::NOP, Some(1), &[], true);
        assert_contract(OpCode::VOID, Some(1), &[], true);
    }
}