symjit 2.17.2

a lightweight just-in-time (JIT) optimizer compiler
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107

use anyhow::Result;

use super::utils::{is_external_func, reg};
use crate::mir::Mir;
use crate::node::Node;
use crate::symbol::Loc;

#[derive(Debug, Clone)]
pub enum Statement {
    Assign {
        lhs: Node,
        rhs: Node,
    },
    Call {
        op: String,
        lhs: Node,
        arg: Node,
        num_args: usize,
    },
    Label {
        label: String,
    },
    Branch {
        label: String,
    },
    BranchIf {
        cond: Node,
        label: String,
        is_else: bool,
    },
}

impl Statement {
    pub fn assign(lhs: Node, rhs: Node) -> Statement {
        Statement::Assign { lhs, rhs }
    }

    pub fn call(op: &str, lhs: Node, arg: Node, num_args: usize) -> Statement {
        Statement::Call {
            op: op.to_string(),
            lhs,
            arg,
            num_args,
        }
    }

    pub fn compile(&mut self, ir: &mut Mir) -> Result<()> {
        match self {
            Statement::Assign { lhs, rhs } => {
                let r = rhs.compile_tree(ir)?;
                Self::save(ir, r, lhs);
            }
            Statement::Call {
                op,
                lhs,
                arg,
                num_args,
            } => {
                if is_external_func(op) {
                    let (l, r) = arg.call_external()?;
                    ir.call(op.as_str(), (r - l) as usize)?;
                    Self::save_result(ir, lhs);
                } else {
                    let _ = arg.compile_tree(ir)?;
                    ir.call(op.as_str(), *num_args)?;
                    Self::save_result(ir, lhs);
                }
            }
            Statement::Label { label } => {
                ir.set_label(label);
            }
            Statement::Branch { label } => {
                ir.branch(label);
            }
            Statement::BranchIf {
                cond,
                label,
                is_else,
            } => {
                let cond = cond.compile_tree(ir)?;
                ir.branch_if(reg(cond), label, *is_else);
            }
        };

        Ok(())
    }

    fn save(ir: &mut Mir, r: u8, v: &Node) {
        if let Node::Var { sym, .. } = v {
            match sym.borrow().loc {
                Loc::Stack(idx) => ir.save_stack(reg(r), idx),
                Loc::Mem(idx) => ir.save_mem(reg(r), idx),
                Loc::Param(_) => unreachable!(),
            }
        }
    }

    fn save_result(ir: &mut Mir, v: &Node) {
        if let Node::Var { sym, .. } = v {
            match sym.borrow().loc {
                Loc::Stack(idx) => ir.save_stack_result(idx),
                Loc::Mem(idx) => ir.save_mem_result(idx),
                Loc::Param(_) => unreachable!(),
            }
        }
    }
}