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

//! [`Constant`] is a typed constant value.

use crate::{
    context::Context,
    irtype::{Aggregate, Type},
    metadata::MetadataIndex,
    value::Value,
};

/// A [`Type`] and constant value, including [`ConstantValue::Undef`] for uninitialized constants.
#[derive(Debug, Clone)]
pub struct Constant {
    pub ty: Type,
    pub value: ConstantValue,
}

/// A constant representation of each of the supported [`Type`]s.
#[derive(Debug, Clone)]
pub enum ConstantValue {
    Undef,
    Unit,
    Bool(bool),
    Uint(u64),
    B256([u8; 32]),
    String(String),
    Array(Vec<Constant>),
    Struct(Vec<Constant>),
}

impl Constant {
    pub fn new_undef(context: &Context, ty: Type) -> Self {
        match ty {
            Type::Array(aggregate) => {
                let (elem_type, count) = context.aggregates[aggregate.0].array_type();
                let elem_init = Self::new_undef(context, *elem_type);
                Constant::new_array(&aggregate, vec![elem_init; *count as usize])
            }
            Type::Struct(aggregate) => {
                let field_types = context.aggregates[aggregate.0].field_types().clone();
                let field_inits = field_types
                    .into_iter()
                    .map(|field_type| Self::new_undef(context, field_type)) // Hrmm, recursive structures would break here.
                    .collect();
                Constant::new_struct(&aggregate, field_inits)
            }
            _otherwise => Constant {
                ty,
                value: ConstantValue::Undef,
            },
        }
    }

    pub fn new_unit() -> Self {
        Constant {
            ty: Type::Unit,
            value: ConstantValue::Unit,
        }
    }

    pub fn new_bool(b: bool) -> Self {
        Constant {
            ty: Type::Bool,
            value: ConstantValue::Bool(b),
        }
    }

    pub fn new_uint(nbits: u8, n: u64) -> Self {
        Constant {
            ty: Type::Uint(nbits),
            value: ConstantValue::Uint(n),
        }
    }

    pub fn new_b256(bytes: [u8; 32]) -> Self {
        Constant {
            ty: Type::B256,
            value: ConstantValue::B256(bytes),
        }
    }

    pub fn new_string(string: String) -> Self {
        // XXX Need to parse the string for escapes?  To do.
        Constant {
            ty: Type::String(string.chars().count() as u64),
            value: ConstantValue::String(string),
        }
    }

    pub fn new_array(aggregate: &Aggregate, elems: Vec<Constant>) -> Self {
        Constant {
            ty: Type::Array(*aggregate),
            value: ConstantValue::Array(elems),
        }
    }

    pub fn new_struct(aggregate: &Aggregate, fields: Vec<Constant>) -> Self {
        Constant {
            ty: Type::Struct(*aggregate),
            value: ConstantValue::Struct(fields),
        }
    }

    pub fn get_undef(context: &mut Context, ty: Type, span_md_idx: Option<MetadataIndex>) -> Value {
        Value::new_constant(context, Constant::new_undef(context, ty), span_md_idx)
    }

    pub fn get_unit(context: &mut Context, span_md_idx: Option<MetadataIndex>) -> Value {
        Value::new_constant(context, Constant::new_unit(), span_md_idx)
    }

    pub fn get_bool(
        context: &mut Context,
        value: bool,
        span_md_idx: Option<MetadataIndex>,
    ) -> Value {
        Value::new_constant(context, Constant::new_bool(value), span_md_idx)
    }

    pub fn get_uint(
        context: &mut Context,
        nbits: u8,
        value: u64,
        span_md_idx: Option<MetadataIndex>,
    ) -> Value {
        Value::new_constant(context, Constant::new_uint(nbits, value), span_md_idx)
    }

    pub fn get_b256(
        context: &mut Context,
        value: [u8; 32],
        span_md_idx: Option<MetadataIndex>,
    ) -> Value {
        Value::new_constant(context, Constant::new_b256(value), span_md_idx)
    }

    pub fn get_string(
        context: &mut Context,
        value: String,
        span_md_idx: Option<MetadataIndex>,
    ) -> Value {
        Value::new_constant(context, Constant::new_string(value), span_md_idx)
    }

    /// `value` must be created as an array constant first, using [`Constant::new_array()`].
    pub fn get_array(
        context: &mut Context,
        value: Constant,
        span_md_idx: Option<MetadataIndex>,
    ) -> Value {
        assert!(matches!(
            value,
            Constant {
                ty: Type::Array(_),
                ..
            }
        ));
        Value::new_constant(context, value, span_md_idx)
    }

    /// `value` must be created as a struct constant first, using [`Constant::new_struct()`].
    pub fn get_struct(
        context: &mut Context,
        value: Constant,
        span_md_idx: Option<MetadataIndex>,
    ) -> Value {
        assert!(matches!(
            value,
            Constant {
                ty: Type::Struct(_),
                ..
            }
        ));
        Value::new_constant(context, value, span_md_idx)
    }
}