celox 0.11.0

Celox HDL Simulator
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
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

use celox::{CompilationWarning, FrontendDiagnostic, Simulator, render_diagnostic};

fn alias_warnings(code: &str) -> Vec<String> {
    let simulator = Simulator::builder(code, "Top").build().unwrap();
    simulator
        .warnings()
        .iter()
        .filter(|warning| {
            matches!(
                warning,
                CompilationWarning::Frontend(FrontendDiagnostic::UnspecifiedOutputCopyOrder { .. })
            )
        })
        .map(|warning| render_diagnostic(warning))
        .collect()
}

#[test]
fn warns_on_named_outputs_inside_an_expression_without_rejecting_the_call() {
    let warnings = alias_warnings(
        r#"
module Top (tmp: output logic<8>, out: output logic) {
    function write_outputs(first: output logic<8>, second: output logic<8>) -> logic {
        first = 8'd1;
        second = 8'd2;
        return 1'b1;
    }
    always_comb {
        tmp = 0;
        out = write_outputs(second: tmp, first: tmp) & 1'b1;
    }
}
"#,
    );
    assert_eq!(warnings.len(), 1, "{warnings:?}");
    let warning = &warnings[0];
    assert!(warning.contains("unspecified_output_copy_order"));
    assert!(warning.contains("first") && warning.contains("second"));
    assert!(warning.contains("tmp[7:0]"));
    assert!(warning.contains("write_outputs(second: tmp, first: tmp)"));
    assert!(warning.contains("use distinct output destinations"));
}

#[test]
fn warns_on_overlapping_slices_and_concatenations_but_not_disjoint_slices() {
    for (actuals, expected) in [
        ("word[7:0], word[11:4]", 1),
        ("{word[15:12], word[3:0]}, word[7:0]", 1),
        ("word[7:0], word[15:8]", 0),
    ] {
        let code = format!(
            r#"
module Top (word: output logic<16>) {{
    function outputs(first: output logic<8>, second: output logic<8>) {{
        first = 8'h12;
        second = 8'h34;
    }}
    always_comb {{
        word = 0;
        outputs({actuals});
    }}
}}
"#
        );
        assert_eq!(alias_warnings(&code).len(), expected, "{actuals}");
    }
}

#[test]
fn static_array_aliases_warn_and_dynamic_indices_are_not_assumed_to_alias() {
    for (actuals, expected) in [
        ("words[0], words[0]", 1),
        ("words[0], words[1]", 0),
        ("words[index], words[0]", 0),
    ] {
        let code = format!(
            r#"
module Top (index: input logic, words: output logic<8>[2]) {{
    function outputs(first: output logic<8>, second: output logic<8>) {{
        first = 8'h12;
        second = 8'h34;
    }}
    always_comb {{
        words = '{{0, 0}};
        outputs({actuals});
    }}
}}
"#
        );
        assert_eq!(alias_warnings(&code).len(), expected, "{actuals}");
    }
}

#[test]
fn input_output_aliasing_does_not_warn_about_copyout_order() {
    assert!(
        alias_warnings(
            r#"
module Top (d: input logic<8>, q: output logic<8>) {
    function update(value: input logic<8>, result: output logic<8>) {
        result = value + 8'd1;
    }
    always_comb {
        q = d;
        update(q, q);
    }
}
"#,
        )
        .is_empty()
    );
}

#[test]
fn repeated_instantiations_report_each_source_call_once() {
    let warnings = alias_warnings(
        r#"
module Child (d: input logic<8>, q: output logic<8>) {
    function outputs(first: output logic<8>, second: output logic<8>) {
        first = 1;
        second = 2;
    }
    function outer(x: input logic<8>, result: output logic<8>) {
        result = x;
        outputs(result, result);
    }
    always_comb { outer(d, q); }
}
module Top (d: input logic<8>, q: output logic<8>, r: output logic<8>) {
    inst a: Child (d, q);
    inst b: Child (d, q: r);
}
"#,
    );
    assert_eq!(warnings.len(), 1, "{warnings:?}");
}