celox-backend-cranelift 0.3.1

Celox Cranelift code-generation backend
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
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
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210

use cranelift::{codegen::ir::BlockArg, prelude::*};
use cranelift_frontend::Switch;

use crate::HashMap;

use super::core::cast_type;
use super::{SIRTranslator, TranslationState};

/// Collect the Cranelift types of all parameters declared on a block.
/// This is used to ensure block-call arguments are cast to the exact
/// types the target block expects, avoiding Cranelift verifier errors
/// such as "arg vN has type i8, expected i16" or "expected i32".
pub(super) fn collect_block_param_types(state: &TranslationState, cl_block: Block) -> Vec<Type> {
    let dfg = &state.builder.func.dfg;
    dfg.block_params(cl_block)
        .iter()
        .map(|&v| dfg.value_type(v))
        .collect()
}

impl SIRTranslator {
    pub(super) fn translate_terminator(
        &self,
        state: &mut TranslationState,
        term: &crate::SIRTerminator,
        block_map: &HashMap<crate::BlockId, Block>,
        next_unit_entry: Option<Block>,
    ) {
        match term {
            crate::SIRTerminator::Jump(to, params) => {
                let target_cl_block = block_map[to];
                // Collect expected param types before mutably borrowing the builder.
                let param_types = collect_block_param_types(state, target_cl_block);

                let mut cl_args: Vec<BlockArg> = Vec::new();
                let mut param_type_idx = 0;
                for reg in params.iter() {
                    let values = state.regs[reg].load_value_chunks(state.builder);
                    let masks = if self.options.four_state {
                        Some(match state.regs[reg].load_mask_chunks(state.builder) {
                            Some(masks) => masks,
                            None => {
                                let mut zeros = Vec::with_capacity(values.len());
                                for value in &values {
                                    let ty = state.builder.func.dfg.value_type(*value);
                                    zeros.push(state.builder.ins().iconst(ty, 0));
                                }
                                zeros
                            }
                        })
                    } else {
                        None
                    };
                    for (chunk_idx, value) in values.iter().enumerate() {
                        let cast_val =
                            cast_type(state.builder, *value, param_types[param_type_idx]);
                        cl_args.push(BlockArg::Value(cast_val));
                        param_type_idx += 1;
                        if let Some(masks) = &masks {
                            let cast_mask = cast_type(
                                state.builder,
                                masks[chunk_idx],
                                param_types[param_type_idx],
                            );
                            cl_args.push(BlockArg::Value(cast_mask));
                            param_type_idx += 1;
                        }
                    }
                }
                debug_assert_eq!(
                    param_type_idx,
                    param_types.len(),
                    "SIR Jump arg count does not match target block param count"
                );
                state.builder.ins().jump(target_cl_block, &cl_args);
            }
            crate::SIRTerminator::Branch {
                cond,
                true_block,
                false_block,
            } => {
                let condition = state.regs[cond].first_value(state.builder);
                let (t_id, t_args) = true_block;
                let (f_id, f_args) = false_block;

                let t_param_types = collect_block_param_types(state, block_map[t_id]);
                let f_param_types = collect_block_param_types(state, block_map[f_id]);
                let mut cl_t_args: Vec<BlockArg> = Vec::new();
                let mut t_param_type_idx = 0;
                for reg in t_args.iter() {
                    let values = state.regs[reg].load_value_chunks(state.builder);
                    let masks = if self.options.four_state {
                        Some(match state.regs[reg].load_mask_chunks(state.builder) {
                            Some(masks) => masks,
                            None => {
                                let mut zeros = Vec::with_capacity(values.len());
                                for value in &values {
                                    let ty = state.builder.func.dfg.value_type(*value);
                                    zeros.push(state.builder.ins().iconst(ty, 0));
                                }
                                zeros
                            }
                        })
                    } else {
                        None
                    };
                    for (chunk_idx, value) in values.iter().enumerate() {
                        let cast_val =
                            cast_type(state.builder, *value, t_param_types[t_param_type_idx]);
                        cl_t_args.push(BlockArg::Value(cast_val));
                        t_param_type_idx += 1;
                        if let Some(masks) = &masks {
                            let cast_mask = cast_type(
                                state.builder,
                                masks[chunk_idx],
                                t_param_types[t_param_type_idx],
                            );
                            cl_t_args.push(BlockArg::Value(cast_mask));
                            t_param_type_idx += 1;
                        }
                    }
                }
                debug_assert_eq!(
                    t_param_type_idx,
                    t_param_types.len(),
                    "SIR Branch true-arg count does not match target block param count"
                );
                let mut cl_f_args: Vec<BlockArg> = Vec::new();
                let mut f_param_type_idx = 0;
                for reg in f_args.iter() {
                    let values = state.regs[reg].load_value_chunks(state.builder);
                    let masks = if self.options.four_state {
                        Some(match state.regs[reg].load_mask_chunks(state.builder) {
                            Some(masks) => masks,
                            None => {
                                let mut zeros = Vec::with_capacity(values.len());
                                for value in &values {
                                    let ty = state.builder.func.dfg.value_type(*value);
                                    zeros.push(state.builder.ins().iconst(ty, 0));
                                }
                                zeros
                            }
                        })
                    } else {
                        None
                    };
                    for (chunk_idx, value) in values.iter().enumerate() {
                        let cast_val =
                            cast_type(state.builder, *value, f_param_types[f_param_type_idx]);
                        cl_f_args.push(BlockArg::Value(cast_val));
                        f_param_type_idx += 1;
                        if let Some(masks) = &masks {
                            let cast_mask = cast_type(
                                state.builder,
                                masks[chunk_idx],
                                f_param_types[f_param_type_idx],
                            );
                            cl_f_args.push(BlockArg::Value(cast_mask));
                            f_param_type_idx += 1;
                        }
                    }
                }
                debug_assert_eq!(
                    f_param_type_idx,
                    f_param_types.len(),
                    "SIR Branch false-arg count does not match target block param count"
                );

                state.builder.ins().brif(
                    condition,
                    block_map[t_id],
                    &cl_t_args,
                    block_map[f_id],
                    &cl_f_args,
                );
            }
            crate::SIRTerminator::Switch {
                selector,
                cases,
                default,
            } => {
                let selector = state.regs[selector].first_value(state.builder);
                let mut switch = Switch::new();
                for case in cases {
                    let digits = case.value.to_u64_digits();
                    let value = match digits.as_slice() {
                        [] => 0,
                        [value] => *value as u128,
                        _ => unreachable!("verified switch key fits eight bits"),
                    };
                    switch.set_entry(value, block_map[&case.target]);
                }
                switch.emit(state.builder, selector, block_map[default]);
            }
            crate::SIRTerminator::Return => {
                if let Some(next_block) = next_unit_entry {
                    state.builder.ins().jump(next_block, &[]);
                } else {
                    let success = state.builder.ins().iconst(types::I64, 0);
                    state.builder.ins().return_(&[success]);
                }
            }
            crate::SIRTerminator::Error(code) => {
                let error = state.builder.ins().iconst(types::I64, *code);

                state.builder.ins().return_(&[error]);
            }
        }
    }
}