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vm/
context.rs

1use crate::get_type;
2use anyhow::{Result, anyhow};
3use cranelift::codegen::ir::FuncRef;
4use cranelift::prelude::{FunctionBuilder, InstBuilder, Value, Variable, types};
5use cranelift_module::FuncId;
6use dynamic::{Dynamic, Type};
7
8#[derive(Clone, Debug)]
9pub enum LocalVar {
10    None,
11    Variable { var: Variable, ty: Type },
12    Value { val: Value, ty: Type },
13    Closure(u32),
14}
15
16impl Into<LocalVar> for (Value, Type) {
17    fn into(self) -> LocalVar {
18        LocalVar::Value { val: self.0, ty: self.1 }
19    }
20}
21
22impl LocalVar {
23    fn normalize_for_var(ctx: &mut BuildContext, val: Value, ty: &Type) -> Value {
24        let Ok(expected) = get_type(ty) else {
25            return val;
26        };
27        let actual = ctx.builder.func.dfg.value_type(val);
28        if actual == expected {
29            return val;
30        }
31
32        if ty.is_bool() && actual.bits() == 1 {
33            let zero = ctx.builder.ins().iconst(types::I8, 0);
34            let one = ctx.builder.ins().iconst(types::I8, 1);
35            return ctx.builder.ins().select(val, one, zero);
36        }
37
38        if expected.is_int() && actual.is_int() {
39            if actual.bits() > expected.bits() {
40                return ctx.builder.ins().ireduce(expected, val);
41            }
42            if actual.bits() < expected.bits() {
43                return if ty.is_uint() { ctx.builder.ins().uextend(expected, val) } else { ctx.builder.ins().sextend(expected, val) };
44            }
45        }
46
47        if expected.is_float() && actual.is_float() {
48            if actual.bits() > expected.bits() {
49                return ctx.builder.ins().fdemote(expected, val);
50            }
51            if actual.bits() < expected.bits() {
52                return ctx.builder.ins().fpromote(expected, val);
53            }
54        }
55
56        val
57    }
58
59    pub fn is_closure(&self) -> bool {
60        if let Self::Closure(_) = self { true } else { false }
61    }
62
63    pub fn get_ty(&self) -> Type {
64        match self {
65            Self::Value { val: _, ty } => ty.clone(),
66            Self::Variable { var: _, ty } => ty.clone(),
67            _ => Type::Any,
68        }
69    }
70
71    pub fn new(ctx: &mut BuildContext, val: Value, ty: Type) -> Result<Self> {
72        let val = Self::normalize_for_var(ctx, val, &ty);
73        let var = ctx.builder.declare_var(get_type(&ty)?);
74        ctx.builder.def_var(var, val);
75        Ok(Self::Variable { var, ty })
76    }
77
78    pub fn get(self, ctx: &mut BuildContext) -> Option<(Value, Type)> {
79        match self {
80            Self::Value { val, ty } => Some((val, ty)),
81            Self::Variable { var, ty } => Some((ctx.builder.use_var(var), ty)),
82            _ => None,
83        }
84    }
85
86    pub fn set(&self, ctx: &mut BuildContext, val: Value) {
87        if let Self::Variable { var, ty } = self {
88            let val = Self::normalize_for_var(ctx, val, ty);
89            ctx.builder.def_var(var.clone(), val);
90        }
91    }
92}
93
94//用来生成 函数代码的上下文
95pub struct BuildContext<'a> {
96    pub builder: FunctionBuilder<'a>,
97    pub(crate) vars: Vec<LocalVar>,
98    pub(crate) fn_refs: Vec<(FuncId, FuncRef)>,
99}
100
101impl<'a> BuildContext<'a> {
102    pub fn new(mut builder: FunctionBuilder<'a>, arg_tys: &[Type]) -> Result<Self> {
103        let entry_block = builder.create_block();
104        builder.append_block_params_for_function_params(entry_block);
105        builder.switch_to_block(entry_block);
106        let mut vars = Vec::new();
107        for (idx, ty) in arg_tys.iter().enumerate() {
108            vars.push(LocalVar::Value { val: builder.block_params(entry_block)[idx], ty: ty.clone() });
109        }
110        Ok(Self { builder, vars, fn_refs: Vec::new() })
111    }
112
113    pub fn get_fn_ref(&mut self, fn_id: FuncId) -> Option<FuncRef> {
114        self.fn_refs.iter().find_map(|f| if f.0 == fn_id { Some(f.1.clone()) } else { None })
115    }
116
117    pub fn get_var(&mut self, idx: u32) -> Result<LocalVar> {
118        self.vars.get(idx as usize).cloned().ok_or(anyhow!("未发现变量 {}", idx))
119    }
120
121    pub fn get_var_ty(&self, idx: u32) -> Option<Type> {
122        self.vars.get(idx as usize).map(|v| v.get_ty())
123    }
124
125    pub fn set_var(&mut self, idx: u32, val: LocalVar) -> Result<()> {
126        if idx as usize == self.vars.len() {
127            if val.is_closure() {
128                self.vars.push(val);
129            } else if let Some(vt) = val.get(self) {
130                let v = LocalVar::new(self, vt.0, vt.1)?;
131                self.vars.push(v);
132            }
133        } else if (idx as usize) < self.vars.len() {
134            if val.is_closure() {
135                self.vars[idx as usize] = val;
136            } else if let Some(vt) = val.get(self) {
137                if matches!(self.vars[idx as usize], LocalVar::None | LocalVar::Value { .. }) {
138                    let v = LocalVar::new(self, vt.0, vt.1)?;
139                    self.vars[idx as usize] = v;
140                } else {
141                    let v = self.vars[idx as usize].clone();
142                    v.set(self, vt.0);
143                }
144            }
145        } else {
146            self.vars.resize(idx as usize, LocalVar::None);
147            if val.is_closure() {
148                self.vars.push(val);
149            } else if let Some(vt) = val.get(self) {
150                let v = LocalVar::new(self, vt.0, vt.1)?;
151                self.vars.push(v);
152            }
153        }
154        Ok(())
155    }
156
157    pub fn get_const(&mut self, v: &Dynamic) -> Result<(Value, Type)> {
158        let ty = v.get_type();
159        if ty.is_f32() {
160            return Ok((self.builder.ins().f32const(v.as_float().unwrap() as f32), ty));
161        } else if ty.is_f64() {
162            return Ok((self.builder.ins().f64const(v.as_float().unwrap()), ty));
163        } else if ty.is_int() || ty.is_uint() {
164            return match ty.width() {
165                1 => Ok((self.builder.ins().iconst(types::I8, v.as_int().unwrap()), ty)),
166                2 => Ok((self.builder.ins().iconst(types::I16, v.as_int().unwrap()), ty)),
167                4 => Ok((self.builder.ins().iconst(types::I32, v.as_int().unwrap()), ty)),
168                8 => Ok((self.builder.ins().iconst(types::I64, v.as_int().unwrap()), ty)),
169                _ => panic!("const {:?}", v),
170            };
171        } else if ty.is_bool() {
172            return if v.is_true() { Ok((self.builder.ins().iconst(types::I8, 1), ty)) } else { Ok((self.builder.ins().iconst(types::I8, 0), ty)) };
173        }
174        Err(anyhow!("未实现 {:?}", v))
175    }
176}