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
|
use crate::build::expr::as_place::PlaceBase;
use crate::build::expr::as_place::PlaceBuilder;
use crate::build::matches::MatchPair;
use crate::build::Builder;
use rustc_middle::mir::*;
use rustc_middle::thir::*;
use rustc_middle::ty;
use rustc_middle::ty::TypeVisitableExt;
use smallvec::SmallVec;
impl<'a, 'tcx> Builder<'a, 'tcx> {
pub(crate) fn field_match_pairs<'pat>(
&mut self,
place: PlaceBuilder<'tcx>,
subpatterns: &'pat [FieldPat<'tcx>],
) -> Vec<MatchPair<'pat, 'tcx>> {
subpatterns
.iter()
.map(|fieldpat| {
let place =
place.clone_project(PlaceElem::Field(fieldpat.field, fieldpat.pattern.ty));
MatchPair::new(place, &fieldpat.pattern, self)
})
.collect()
}
pub(crate) fn prefix_slice_suffix<'pat>(
&mut self,
match_pairs: &mut SmallVec<[MatchPair<'pat, 'tcx>; 1]>,
place: &PlaceBuilder<'tcx>,
prefix: &'pat [Box<Pat<'tcx>>],
opt_slice: &'pat Option<Box<Pat<'tcx>>>,
suffix: &'pat [Box<Pat<'tcx>>],
) {
let tcx = self.tcx;
let (min_length, exact_size) = if let Some(place_resolved) = place.try_to_place(self) {
match place_resolved.ty(&self.local_decls, tcx).ty.kind() {
ty::Array(_, length) => (length.eval_target_usize(tcx, self.param_env), true),
_ => ((prefix.len() + suffix.len()).try_into().unwrap(), false),
}
} else {
((prefix.len() + suffix.len()).try_into().unwrap(), false)
};
match_pairs.extend(prefix.iter().enumerate().map(|(idx, subpattern)| {
let elem =
ProjectionElem::ConstantIndex { offset: idx as u64, min_length, from_end: false };
MatchPair::new(place.clone_project(elem), subpattern, self)
}));
if let Some(subslice_pat) = opt_slice {
let suffix_len = suffix.len() as u64;
let subslice = place.clone_project(PlaceElem::Subslice {
from: prefix.len() as u64,
to: if exact_size { min_length - suffix_len } else { suffix_len },
from_end: !exact_size,
});
match_pairs.push(MatchPair::new(subslice, subslice_pat, self));
}
match_pairs.extend(suffix.iter().rev().enumerate().map(|(idx, subpattern)| {
let end_offset = (idx + 1) as u64;
let elem = ProjectionElem::ConstantIndex {
offset: if exact_size { min_length - end_offset } else { end_offset },
min_length,
from_end: !exact_size,
};
let place = place.clone_project(elem);
MatchPair::new(place, subpattern, self)
}));
}
/// Creates a false edge to `imaginary_target` and a real edge to
/// real_target. If `imaginary_target` is none, or is the same as the real
/// target, a Goto is generated instead to simplify the generated MIR.
pub(crate) fn false_edges(
&mut self,
from_block: BasicBlock,
real_target: BasicBlock,
imaginary_target: Option<BasicBlock>,
source_info: SourceInfo,
) {
match imaginary_target {
Some(target) if target != real_target => {
self.cfg.terminate(
from_block,
source_info,
TerminatorKind::FalseEdge { real_target, imaginary_target: target },
);
}
_ => self.cfg.goto(from_block, source_info, real_target),
}
}
}
impl<'pat, 'tcx> MatchPair<'pat, 'tcx> {
pub(in crate::build) fn new(
mut place: PlaceBuilder<'tcx>,
pattern: &'pat Pat<'tcx>,
cx: &Builder<'_, 'tcx>,
) -> MatchPair<'pat, 'tcx> {
// Force the place type to the pattern's type.
// FIXME(oli-obk): can we use this to simplify slice/array pattern hacks?
if let Some(resolved) = place.resolve_upvar(cx) {
place = resolved;
}
// Only add the OpaqueCast projection if the given place is an opaque type and the
// expected type from the pattern is not.
let may_need_cast = match place.base() {
PlaceBase::Local(local) => {
let ty = Place::ty_from(local, place.projection(), &cx.local_decls, cx.tcx).ty;
ty != pattern.ty && ty.has_opaque_types()
}
_ => true,
};
if may_need_cast {
place = place.project(ProjectionElem::OpaqueCast(pattern.ty));
}
MatchPair { place, pattern }
}
}
|
