clippy_lints/src/atomic_ordering.rs

   1 use crate::utils::{match_def_path, span_help_and_lint};
   2 use if_chain::if_chain;
   3 use rustc::ty;
   4 use rustc_hir::def_id::DefId;
   5 use rustc_hir::*;
   6 use rustc_lint::{LateContext, LateLintPass};
   7 use rustc_session::{declare_lint_pass, declare_tool_lint};
   8
   9 declare_clippy_lint! {
  10     /// **What it does:** Checks for usage of invalid atomic
  11     /// ordering in Atomic*::{load, store} calls.
  12     ///
  13     /// **Why is this bad?** Using an invalid atomic ordering
  14     /// will cause a panic at run-time.
  15     ///
  16     /// **Known problems:** None.
  17     ///
  18     /// **Example:**
  19     /// ```rust,no_run
  20     /// # use std::sync::atomic::{AtomicBool, Ordering};
  21     ///
  22     /// let x = AtomicBool::new(true);
  23     ///
  24     /// let _ = x.load(Ordering::Release);
  25     /// let _ = x.load(Ordering::AcqRel);
  26     ///
  27     /// x.store(false, Ordering::Acquire);
  28     /// x.store(false, Ordering::AcqRel);
  29     /// ```
  30     pub INVALID_ATOMIC_ORDERING,
  31     correctness,
  32     "usage of invalid atomic ordering in atomic load/store calls"
  33 }
  34
  35 declare_lint_pass!(AtomicOrdering => [INVALID_ATOMIC_ORDERING]);
  36
  37 const ATOMIC_TYPES: [&str; 12] = [
  38     "AtomicBool",
  39     "AtomicI8",
  40     "AtomicI16",
  41     "AtomicI32",
  42     "AtomicI64",
  43     "AtomicIsize",
  44     "AtomicPtr",
  45     "AtomicU8",
  46     "AtomicU16",
  47     "AtomicU32",
  48     "AtomicU64",
  49     "AtomicUsize",
  50 ];
  51
  52 fn type_is_atomic(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
  53     if let ty::Adt(&ty::AdtDef { did, .. }, _) = cx.tables.expr_ty(expr).kind {
  54         ATOMIC_TYPES
  55             .iter()
  56             .any(|ty| match_def_path(cx, did, &["core", "sync", "atomic", ty]))
  57     } else {
  58         false
  59     }
  60 }
  61
  62 fn match_ordering_def_path(cx: &LateContext<'_, '_>, did: DefId, orderings: &[&str]) -> bool {
  63     orderings
  64         .iter()
  65         .any(|ordering| match_def_path(cx, did, &["core", "sync", "atomic", "Ordering", ordering]))
  66 }
  67
  68 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AtomicOrdering {
  69     fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
  70         if_chain! {
  71             if let ExprKind::MethodCall(ref method_path, _, args) = &expr.kind;
  72             let method = method_path.ident.name.as_str();
  73             if type_is_atomic(cx, &args[0]);
  74             if method == "load" || method == "store";
  75             let ordering_arg = if method == "load" { &args[1] } else { &args[2] };
  76             if let ExprKind::Path(ref ordering_qpath) = ordering_arg.kind;
  77             if let Some(ordering_def_id) = cx.tables.qpath_res(ordering_qpath, ordering_arg.hir_id).opt_def_id();
  78             then {
  79                 if method == "load" &&
  80                     match_ordering_def_path(cx, ordering_def_id, &["Release", "AcqRel"]) {
  81                     span_help_and_lint(
  82                         cx,
  83                         INVALID_ATOMIC_ORDERING,
  84                         ordering_arg.span,
  85                         "atomic loads cannot have `Release` and `AcqRel` ordering",
  86                         "consider using ordering modes `Acquire`, `SeqCst` or `Relaxed`"
  87                     );
  88                 } else if method == "store" &&
  89                     match_ordering_def_path(cx, ordering_def_id, &["Acquire", "AcqRel"]) {
  90                     span_help_and_lint(
  91                         cx,
  92                         INVALID_ATOMIC_ORDERING,
  93                         ordering_arg.span,
  94                         "atomic stores cannot have `Acquire` and `AcqRel` ordering",
  95                         "consider using ordering modes `Release`, `SeqCst` or `Relaxed`"
  96                     );
  97                 }
  98             }
  99         }
 100     }
 101 }