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
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179

use rustc_middle::thir::*;
use rustc_middle::ty::Const;

pub trait Visitor<'a, 'tcx: 'a>: Sized {
    fn thir(&self) -> &'a Thir<'tcx>;

    fn visit_expr(&mut self, expr: &Expr<'tcx>) {
        walk_expr(self, expr);
    }

    fn visit_stmt(&mut self, stmt: &Stmt<'tcx>) {
        walk_stmt(self, stmt);
    }

    fn visit_block(&mut self, block: &Block) {
        walk_block(self, block);
    }

    fn visit_arm(&mut self, arm: &Arm<'tcx>) {
        walk_arm(self, arm);
    }

    fn visit_const(&mut self, _cnst: &'tcx Const<'tcx>) {}
}

pub fn walk_expr<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, expr: &Expr<'tcx>) {
    use ExprKind::*;
    match expr.kind {
        Scope { value, region_scope: _, lint_level: _ } => {
            visitor.visit_expr(&visitor.thir()[value])
        }
        Box { value } => visitor.visit_expr(&visitor.thir()[value]),
        If { cond, then, else_opt } => {
            visitor.visit_expr(&visitor.thir()[cond]);
            visitor.visit_expr(&visitor.thir()[then]);
            if let Some(else_expr) = else_opt {
                visitor.visit_expr(&visitor.thir()[else_expr]);
            }
        }
        Call { fun, ref args, ty: _, from_hir_call: _, fn_span: _ } => {
            visitor.visit_expr(&visitor.thir()[fun]);
            for &arg in &**args {
                visitor.visit_expr(&visitor.thir()[arg]);
            }
        }
        Deref { arg } => visitor.visit_expr(&visitor.thir()[arg]),
        Binary { lhs, rhs, op: _ } | LogicalOp { lhs, rhs, op: _ } => {
            visitor.visit_expr(&visitor.thir()[lhs]);
            visitor.visit_expr(&visitor.thir()[rhs]);
        }
        Unary { arg, op: _ } => visitor.visit_expr(&visitor.thir()[arg]),
        Cast { source } => visitor.visit_expr(&visitor.thir()[source]),
        Use { source } => visitor.visit_expr(&visitor.thir()[source]),
        NeverToAny { source } => visitor.visit_expr(&visitor.thir()[source]),
        Pointer { source, cast: _ } => visitor.visit_expr(&visitor.thir()[source]),
        Loop { body } => visitor.visit_expr(&visitor.thir()[body]),
        Match { scrutinee, ref arms } => {
            visitor.visit_expr(&visitor.thir()[scrutinee]);
            for &arm in &**arms {
                visitor.visit_arm(&visitor.thir()[arm]);
            }
        }
        Block { ref body } => visitor.visit_block(body),
        Assign { lhs, rhs } | AssignOp { lhs, rhs, op: _ } => {
            visitor.visit_expr(&visitor.thir()[lhs]);
            visitor.visit_expr(&visitor.thir()[rhs]);
        }
        Field { lhs, name: _ } => visitor.visit_expr(&visitor.thir()[lhs]),
        Index { lhs, index } => {
            visitor.visit_expr(&visitor.thir()[lhs]);
            visitor.visit_expr(&visitor.thir()[index]);
        }
        VarRef { id: _ } | UpvarRef { closure_def_id: _, var_hir_id: _ } => {}
        Borrow { arg, borrow_kind: _ } => visitor.visit_expr(&visitor.thir()[arg]),
        AddressOf { arg, mutability: _ } => visitor.visit_expr(&visitor.thir()[arg]),
        Break { value, label: _ } => {
            if let Some(value) = value {
                visitor.visit_expr(&visitor.thir()[value])
            }
        }
        Continue { label: _ } => {}
        Return { value } => {
            if let Some(value) = value {
                visitor.visit_expr(&visitor.thir()[value])
            }
        }
        ConstBlock { value } => visitor.visit_const(value),
        Repeat { value, count } => {
            visitor.visit_expr(&visitor.thir()[value]);
            visitor.visit_const(count);
        }
        Array { ref fields } | Tuple { ref fields } => {
            for &field in &**fields {
                visitor.visit_expr(&visitor.thir()[field]);
            }
        }
        Adt { ref fields, ref base, adt_def: _, variant_index: _, substs: _, user_ty: _ } => {
            for field in &**fields {
                visitor.visit_expr(&visitor.thir()[field.expr]);
            }
            if let Some(base) = base {
                visitor.visit_expr(&visitor.thir()[base.base]);
            }
        }
        PlaceTypeAscription { source, user_ty: _ } | ValueTypeAscription { source, user_ty: _ } => {
            visitor.visit_expr(&visitor.thir()[source])
        }
        Closure { closure_id: _, substs: _, upvars: _, movability: _, fake_reads: _ } => {}
        Literal { literal, user_ty: _, const_id: _ } => visitor.visit_const(literal),
        StaticRef { literal, def_id: _ } => visitor.visit_const(literal),
        InlineAsm { ref operands, template: _, options: _, line_spans: _ } => {
            for op in &**operands {
                use InlineAsmOperand::*;
                match op {
                    In { expr, reg: _ }
                    | Out { expr: Some(expr), reg: _, late: _ }
                    | InOut { expr, reg: _, late: _ }
                    | SymFn { expr } => visitor.visit_expr(&visitor.thir()[*expr]),
                    SplitInOut { in_expr, out_expr, reg: _, late: _ } => {
                        visitor.visit_expr(&visitor.thir()[*in_expr]);
                        if let Some(out_expr) = out_expr {
                            visitor.visit_expr(&visitor.thir()[*out_expr]);
                        }
                    }
                    Out { expr: None, reg: _, late: _ }
                    | Const { value: _, span: _ }
                    | SymStatic { def_id: _ } => {}
                }
            }
        }
        ThreadLocalRef(_) => {}
        LlvmInlineAsm { ref outputs, ref inputs, asm: _ } => {
            for &out_expr in &**outputs {
                visitor.visit_expr(&visitor.thir()[out_expr]);
            }
            for &in_expr in &**inputs {
                visitor.visit_expr(&visitor.thir()[in_expr]);
            }
        }
        Yield { value } => visitor.visit_expr(&visitor.thir()[value]),
    }
}

pub fn walk_stmt<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, stmt: &Stmt<'tcx>) {
    match stmt.kind {
        StmtKind::Expr { expr, scope: _ } => visitor.visit_expr(&visitor.thir()[expr]),
        StmtKind::Let {
            initializer,
            remainder_scope: _,
            init_scope: _,
            pattern: _,
            lint_level: _,
        } => {
            if let Some(init) = initializer {
                visitor.visit_expr(&visitor.thir()[init]);
            }
        }
    }
}

pub fn walk_block<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, block: &Block) {
    for &stmt in &*block.stmts {
        visitor.visit_stmt(&visitor.thir()[stmt]);
    }
    if let Some(expr) = block.expr {
        visitor.visit_expr(&visitor.thir()[expr]);
    }
}

pub fn walk_arm<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, arm: &Arm<'tcx>) {
    match arm.guard {
        Some(Guard::If(expr)) => visitor.visit_expr(&visitor.thir()[expr]),
        Some(Guard::IfLet(ref _pat, expr)) => {
            visitor.visit_expr(&visitor.thir()[expr]);
        }
        None => {}
    }
    visitor.visit_expr(&visitor.thir()[arm.body]);
}