mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-12-21 02:23:19 +00:00
64ae3ae006
Specifically, rename the `Const` struct as `ConstS` and re-introduce `Const` as this: ``` pub struct Const<'tcx>(&'tcx Interned<ConstS>); ``` This now matches `Ty` and `Predicate` more closely, including using pointer-based `eq` and `hash`. Notable changes: - `mk_const` now takes a `ConstS`. - `Const` was copy, despite being 48 bytes. Now `ConstS` is not, so need a we need separate arena for it, because we can't use the `Dropless` one any more. - Many `&'tcx Const<'tcx>`/`&Const<'tcx>` to `Const<'tcx>` changes - Many `ct.ty` to `ct.ty()` and `ct.val` to `ct.val()` changes. - Lots of tedious sigil fiddling.
68 lines
2.2 KiB
Rust
68 lines
2.2 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_help;
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use clippy_utils::source::snippet;
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use if_chain::if_chain;
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use rustc_hir::{Expr, ExprKind};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_middle::mir::interpret::ConstValue;
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use rustc_middle::ty::layout::LayoutOf;
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use rustc_middle::ty::{self, ConstKind};
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use rustc_session::{declare_tool_lint, impl_lint_pass};
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declare_clippy_lint! {
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/// ### What it does
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/// Checks for local arrays that may be too large.
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///
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/// ### Why is this bad?
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/// Large local arrays may cause stack overflow.
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///
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/// ### Example
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/// ```rust,ignore
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/// let a = [0u32; 1_000_000];
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/// ```
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#[clippy::version = "1.41.0"]
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pub LARGE_STACK_ARRAYS,
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pedantic,
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"allocating large arrays on stack may cause stack overflow"
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}
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pub struct LargeStackArrays {
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maximum_allowed_size: u64,
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}
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impl LargeStackArrays {
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#[must_use]
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pub fn new(maximum_allowed_size: u64) -> Self {
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Self { maximum_allowed_size }
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}
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}
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impl_lint_pass!(LargeStackArrays => [LARGE_STACK_ARRAYS]);
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impl<'tcx> LateLintPass<'tcx> for LargeStackArrays {
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fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
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if_chain! {
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if let ExprKind::Repeat(_, _) = expr.kind;
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if let ty::Array(element_type, cst) = cx.typeck_results().expr_ty(expr).kind();
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if let ConstKind::Value(ConstValue::Scalar(element_count)) = cst.val();
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if let Ok(element_count) = element_count.to_machine_usize(&cx.tcx);
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if let Ok(element_size) = cx.layout_of(*element_type).map(|l| l.size.bytes());
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if self.maximum_allowed_size < element_count * element_size;
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then {
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span_lint_and_help(
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cx,
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LARGE_STACK_ARRAYS,
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expr.span,
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&format!(
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"allocating a local array larger than {} bytes",
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self.maximum_allowed_size
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),
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None,
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&format!(
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"consider allocating on the heap with `vec!{}.into_boxed_slice()`",
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snippet(cx, expr.span, "[...]")
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),
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);
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}
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}
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}
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}
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