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
|
use super::MISSING_SPIN_LOOP;
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::is_no_std_crate;
use rustc_errors::Applicability;
use rustc_hir::{Block, Expr, ExprKind};
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_span::sym;
fn unpack_cond<'tcx>(cond: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
match &cond.kind {
ExprKind::Block(
Block {
stmts: [],
expr: Some(e),
..
},
_,
)
| ExprKind::Unary(_, e) => unpack_cond(e),
ExprKind::Binary(_, l, r) => {
let l = unpack_cond(l);
if let ExprKind::MethodCall(..) = l.kind {
l
} else {
unpack_cond(r)
}
},
_ => cond,
}
}
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, cond: &'tcx Expr<'_>, body: &'tcx Expr<'_>) {
if_chain! {
if let ExprKind::Block(Block { stmts: [], expr: None, ..}, _) = body.kind;
if let ExprKind::MethodCall(method, callee, ..) = unpack_cond(cond).kind;
if [sym::load, sym::compare_exchange, sym::compare_exchange_weak].contains(&method.ident.name);
if let ty::Adt(def, _substs) = cx.typeck_results().expr_ty(callee).kind();
if cx.tcx.is_diagnostic_item(sym::AtomicBool, def.did());
then {
span_lint_and_sugg(
cx,
MISSING_SPIN_LOOP,
body.span,
"busy-waiting loop should at least have a spin loop hint",
"try this",
(if is_no_std_crate(cx) {
"{ core::hint::spin_loop() }"
} else {
"{ std::hint::spin_loop() }"
}).into(),
Applicability::MachineApplicable
);
}
}
}
|
