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Commit | Line | Data |
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dfeec247 XL |
1 | use crate::build::matches::MatchPair; |
2 | use crate::build::Builder; | |
3dfed10e | 3 | use crate::thir::*; |
ba9703b0 XL |
4 | use rustc_middle::mir::*; |
5 | use rustc_middle::ty; | |
dfeec247 XL |
6 | use smallvec::SmallVec; |
7 | use std::convert::TryInto; | |
dfeec247 XL |
8 | |
9 | impl<'a, 'tcx> Builder<'a, 'tcx> { | |
10 | crate fn field_match_pairs<'pat>( | |
11 | &mut self, | |
12 | place: Place<'tcx>, | |
13 | subpatterns: &'pat [FieldPat<'tcx>], | |
14 | ) -> Vec<MatchPair<'pat, 'tcx>> { | |
15 | subpatterns | |
16 | .iter() | |
17 | .map(|fieldpat| { | |
ba9703b0 XL |
18 | let place = |
19 | self.hir.tcx().mk_place_field(place, fieldpat.field, fieldpat.pattern.ty); | |
dfeec247 XL |
20 | MatchPair::new(place, &fieldpat.pattern) |
21 | }) | |
22 | .collect() | |
23 | } | |
24 | ||
25 | crate fn prefix_slice_suffix<'pat>( | |
26 | &mut self, | |
27 | match_pairs: &mut SmallVec<[MatchPair<'pat, 'tcx>; 1]>, | |
28 | place: &Place<'tcx>, | |
29 | prefix: &'pat [Pat<'tcx>], | |
30 | opt_slice: Option<&'pat Pat<'tcx>>, | |
31 | suffix: &'pat [Pat<'tcx>], | |
32 | ) { | |
33 | let tcx = self.hir.tcx(); | |
34 | let (min_length, exact_size) = match place.ty(&self.local_decls, tcx).ty.kind { | |
35 | ty::Array(_, length) => { | |
36 | (length.eval_usize(tcx, self.hir.param_env).try_into().unwrap(), true) | |
37 | } | |
38 | _ => ((prefix.len() + suffix.len()).try_into().unwrap(), false), | |
39 | }; | |
40 | ||
41 | match_pairs.extend(prefix.iter().enumerate().map(|(idx, subpattern)| { | |
42 | let elem = | |
43 | ProjectionElem::ConstantIndex { offset: idx as u32, min_length, from_end: false }; | |
ba9703b0 | 44 | let place = tcx.mk_place_elem(*place, elem); |
dfeec247 XL |
45 | MatchPair::new(place, subpattern) |
46 | })); | |
47 | ||
48 | if let Some(subslice_pat) = opt_slice { | |
49 | let suffix_len = suffix.len() as u32; | |
50 | let subslice = tcx.mk_place_elem( | |
ba9703b0 | 51 | *place, |
dfeec247 XL |
52 | ProjectionElem::Subslice { |
53 | from: prefix.len() as u32, | |
54 | to: if exact_size { min_length - suffix_len } else { suffix_len }, | |
55 | from_end: !exact_size, | |
56 | }, | |
57 | ); | |
58 | match_pairs.push(MatchPair::new(subslice, subslice_pat)); | |
59 | } | |
60 | ||
61 | match_pairs.extend(suffix.iter().rev().enumerate().map(|(idx, subpattern)| { | |
62 | let end_offset = (idx + 1) as u32; | |
63 | let elem = ProjectionElem::ConstantIndex { | |
64 | offset: if exact_size { min_length - end_offset } else { end_offset }, | |
65 | min_length, | |
66 | from_end: !exact_size, | |
67 | }; | |
ba9703b0 | 68 | let place = tcx.mk_place_elem(*place, elem); |
dfeec247 XL |
69 | MatchPair::new(place, subpattern) |
70 | })); | |
71 | } | |
72 | ||
73 | /// Creates a false edge to `imaginary_target` and a real edge to | |
74 | /// real_target. If `imaginary_target` is none, or is the same as the real | |
75 | /// target, a Goto is generated instead to simplify the generated MIR. | |
76 | crate fn false_edges( | |
77 | &mut self, | |
78 | from_block: BasicBlock, | |
79 | real_target: BasicBlock, | |
80 | imaginary_target: Option<BasicBlock>, | |
81 | source_info: SourceInfo, | |
82 | ) { | |
83 | match imaginary_target { | |
84 | Some(target) if target != real_target => { | |
85 | self.cfg.terminate( | |
86 | from_block, | |
87 | source_info, | |
f035d41b | 88 | TerminatorKind::FalseEdge { real_target, imaginary_target: target }, |
dfeec247 XL |
89 | ); |
90 | } | |
91 | _ => self.cfg.goto(from_block, source_info, real_target), | |
92 | } | |
93 | } | |
94 | } | |
95 | ||
96 | impl<'pat, 'tcx> MatchPair<'pat, 'tcx> { | |
97 | crate fn new(place: Place<'tcx>, pattern: &'pat Pat<'tcx>) -> MatchPair<'pat, 'tcx> { | |
98 | MatchPair { place, pattern } | |
99 | } | |
100 | } |