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Dont lint large_stack_array inside static items

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Fixes #9460
This commit is contained in:
Lukas Lueg 2022-09-11 16:24:33 +02:00
parent c8c2a234b3
commit 6f41a44c3e
3 changed files with 34 additions and 30 deletions
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50
clippy_lints/src/large_stack_arrays.rs
View File

@ -1,7 +1,6 @@
use clippy_utils::diagnostics::span_lint_and_help;
use clippy_utils::source::snippet;
use if_chain::if_chain;
use rustc_hir::{Expr, ExprKind};
use rustc_hir::{Expr, ExprKind, Item, ItemKind, Node};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty::layout::LayoutOf;
use rustc_middle::ty::{self, ConstKind};
@ -39,29 +38,28 @@ pub fn new(maximum_allowed_size: u64) -> Self {
impl<'tcx> LateLintPass<'tcx> for LargeStackArrays {
fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
if_chain! {
if let ExprKind::Repeat(_, _) = expr.kind;
if let ty::Array(element_type, cst) = cx.typeck_results().expr_ty(expr).kind();
if let ConstKind::Value(ty::ValTree::Leaf(element_count)) = cst.kind();
if let Ok(element_count) = element_count.try_to_machine_usize(cx.tcx);
if let Ok(element_size) = cx.layout_of(*element_type).map(|l| l.size.bytes());
if self.maximum_allowed_size < element_count * element_size;
then {
span_lint_and_help(
cx,
LARGE_STACK_ARRAYS,
expr.span,
&format!(
"allocating a local array larger than {} bytes",
self.maximum_allowed_size
),
None,
&format!(
"consider allocating on the heap with `vec!{}.into_boxed_slice()`",
snippet(cx, expr.span, "[...]")
),
);
}
}
if let ExprKind::Repeat(_, _) = expr.kind
&& let ty::Array(element_type, cst) = cx.typeck_results().expr_ty(expr).kind()
&& let ConstKind::Value(ty::ValTree::Leaf(element_count)) = cst.kind()
&& let Ok(element_count) = element_count.try_to_machine_usize(cx.tcx)
&& let Ok(element_size) = cx.layout_of(*element_type).map(|l| l.size.bytes())
&& !cx.tcx.hir().parent_iter(expr.hir_id)
.any(|(_, node)| matches!(node, Node::Item(Item { kind: ItemKind::Static(..), .. })))
&& self.maximum_allowed_size < element_count * element_size {
span_lint_and_help(
cx,
LARGE_STACK_ARRAYS,
expr.span,
&format!(
"allocating a local array larger than {} bytes",
self.maximum_allowed_size
),
None,
&format!(
"consider allocating on the heap with `vec!{}.into_boxed_slice()`",
snippet(cx, expr.span, "[...]")
),
);
}
}
}

6
tests/ui/large_stack_arrays.rs
View File

@ -12,6 +12,12 @@ enum E {
T(u32),
}
pub static DOESNOTLINT: [u8; 512_001] = [0; 512_001];
pub static DOESNOTLINT2: [u8; 512_001] = {
let x = 0;
[x; 512_001]
};
fn main() {
let bad = (
[0u32; 20_000_000],

8
tests/ui/large_stack_arrays.stderr
View File

@ -1,5 +1,5 @@
error: allocating a local array larger than 512000 bytes
--> $DIR/large_stack_arrays.rs:17:9
--> $DIR/large_stack_arrays.rs:23:9
|
LL | [0u32; 20_000_000],
| ^^^^^^^^^^^^^^^^^^
@ -8,7 +8,7 @@ LL | [0u32; 20_000_000],
= help: consider allocating on the heap with `vec![0u32; 20_000_000].into_boxed_slice()`
error: allocating a local array larger than 512000 bytes
--> $DIR/large_stack_arrays.rs:18:9
--> $DIR/large_stack_arrays.rs:24:9
|
LL | [S { data: [0; 32] }; 5000],
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -16,7 +16,7 @@ LL | [S { data: [0; 32] }; 5000],
= help: consider allocating on the heap with `vec![S { data: [0; 32] }; 5000].into_boxed_slice()`
error: allocating a local array larger than 512000 bytes
--> $DIR/large_stack_arrays.rs:19:9
--> $DIR/large_stack_arrays.rs:25:9
|
LL | [Some(""); 20_000_000],
| ^^^^^^^^^^^^^^^^^^^^^^
@ -24,7 +24,7 @@ LL | [Some(""); 20_000_000],
= help: consider allocating on the heap with `vec![Some(""); 20_000_000].into_boxed_slice()`
error: allocating a local array larger than 512000 bytes
--> $DIR/large_stack_arrays.rs:20:9
--> $DIR/large_stack_arrays.rs:26:9
|
LL | [E::T(0); 5000],
| ^^^^^^^^^^^^^^^