5fa961b951
Specifically, change `Ty` from this: ``` pub type Ty<'tcx> = &'tcx TyS<'tcx>; ``` to this ``` pub struct Ty<'tcx>(Interned<'tcx, TyS<'tcx>>); ``` There are two benefits to this. - It's now a first class type, so we can define methods on it. This means we can move a lot of methods away from `TyS`, leaving `TyS` as a barely-used type, which is appropriate given that it's not meant to be used directly. - The uniqueness requirement is now explicit, via the `Interned` type. E.g. the pointer-based `Eq` and `Hash` comes from `Interned`, rather than via `TyS`, which wasn't obvious at all. Much of this commit is boring churn. The interesting changes are in these files: - compiler/rustc_middle/src/arena.rs - compiler/rustc_middle/src/mir/visit.rs - compiler/rustc_middle/src/ty/context.rs - compiler/rustc_middle/src/ty/mod.rs Specifically: - Most mentions of `TyS` are removed. It's very much a dumb struct now; `Ty` has all the smarts. - `TyS` now has `crate` visibility instead of `pub`. - `TyS::make_for_test` is removed in favour of the static `BOOL_TY`, which just works better with the new structure. - The `Eq`/`Ord`/`Hash` impls are removed from `TyS`. `Interned`s impls of `Eq`/`Hash` now suffice. `Ord` is now partly on `Interned` (pointer-based, for the `Equal` case) and partly on `TyS` (contents-based, for the other cases). - There are many tedious sigil adjustments, i.e. adding or removing `*` or `&`. They seem to be unavoidable.
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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