diff options
| -rw-r--r-- | clippy_lints/src/large_stack_arrays.rs | 50 | ||||
| -rw-r--r-- | tests/ui/auxiliary/proc_macros.rs | 17 | ||||
| -rw-r--r-- | tests/ui/large_stack_arrays.rs | 16 | ||||
| -rw-r--r-- | tests/ui/large_stack_arrays.stderr | 47 |
4 files changed, 102 insertions, 28 deletions
diff --git a/clippy_lints/src/large_stack_arrays.rs b/clippy_lints/src/large_stack_arrays.rs index 9214e870e92..208d1bb6e68 100644 --- a/clippy_lints/src/large_stack_arrays.rs +++ b/clippy_lints/src/large_stack_arrays.rs @@ -1,7 +1,8 @@ use clippy_utils::diagnostics::span_lint_and_then; +use clippy_utils::is_from_proc_macro; use clippy_utils::macros::macro_backtrace; use clippy_utils::source::snippet; -use rustc_hir::{Expr, ExprKind, Item, ItemKind, Node}; +use rustc_hir::{ArrayLen, Expr, ExprKind, Item, ItemKind, Node}; use rustc_lint::{LateContext, LateLintPass}; use rustc_middle::ty::layout::LayoutOf; use rustc_middle::ty::{self, ConstKind}; @@ -27,21 +28,41 @@ declare_clippy_lint! { pub struct LargeStackArrays { maximum_allowed_size: u128, + prev_vec_macro_callsite: Option<Span>, } impl LargeStackArrays { #[must_use] pub fn new(maximum_allowed_size: u128) -> Self { - Self { maximum_allowed_size } + Self { + maximum_allowed_size, + prev_vec_macro_callsite: None, + } + } + + /// Check if the given span of an expr is already in a `vec!` call. + fn is_from_vec_macro(&mut self, cx: &LateContext<'_>, span: Span) -> bool { + // First, we check if this is span is within the last encountered `vec!` macro's root callsite. + self.prev_vec_macro_callsite + .is_some_and(|vec_mac| vec_mac.contains(span)) + || { + // Then, we try backtracking the macro expansions, to see if there's a `vec!` macro, + // and update the `prev_vec_macro_callsite`. + let res = macro_backtrace(span).any(|mac| cx.tcx.is_diagnostic_item(sym::vec_macro, mac.def_id)); + if res { + self.prev_vec_macro_callsite = Some(span.source_callsite()); + } + res + } } } impl_lint_pass!(LargeStackArrays => [LARGE_STACK_ARRAYS]); impl<'tcx> LateLintPass<'tcx> for LargeStackArrays { - fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) { + fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'tcx>) { if let ExprKind::Repeat(_, _) | ExprKind::Array(_) = expr.kind - && !is_from_vec_macro(cx, expr.span) + && !self.is_from_vec_macro(cx, expr.span) && 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_target_usize(cx.tcx) @@ -66,7 +87,7 @@ impl<'tcx> LateLintPass<'tcx> for LargeStackArrays { self.maximum_allowed_size ), |diag| { - if !expr.span.from_expansion() { + if !might_be_expanded(cx, expr) { diag.help(format!( "consider allocating on the heap with `vec!{}.into_boxed_slice()`", snippet(cx, expr.span, "[...]") @@ -78,7 +99,20 @@ impl<'tcx> LateLintPass<'tcx> for LargeStackArrays { } } -/// We shouldn't lint messages if the expr is already in a `vec!` call -fn is_from_vec_macro(cx: &LateContext<'_>, expr_span: Span) -> bool { - macro_backtrace(expr_span).any(|mac| cx.tcx.is_diagnostic_item(sym::vec_macro, mac.def_id)) +/// Only giving help messages if the expr does not contains macro expanded codes. +fn might_be_expanded<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) -> bool { + /// Check if the span of `ArrayLen` of a repeat expression is within the expr's span, + /// if not, meaning this repeat expr is definitely from some proc-macro. + /// + /// This is a fail-safe to a case where even the `is_from_proc_macro` is unable to determain the + /// correct result. + fn repeat_expr_might_be_expanded<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) -> bool { + let ExprKind::Repeat(_, ArrayLen::Body(anon_const)) = expr.kind else { + return false; + }; + let len_span = cx.tcx.def_span(anon_const.def_id); + !expr.span.contains(len_span) + } + + expr.span.from_expansion() || is_from_proc_macro(cx, expr) || repeat_expr_might_be_expanded(cx, expr) } diff --git a/tests/ui/auxiliary/proc_macros.rs b/tests/ui/auxiliary/proc_macros.rs index 3303eb14567..6e6919cd295 100644 --- a/tests/ui/auxiliary/proc_macros.rs +++ b/tests/ui/auxiliary/proc_macros.rs @@ -9,6 +9,7 @@ use proc_macro::token_stream::IntoIter; use proc_macro::Delimiter::{self, Brace, Parenthesis}; use proc_macro::Spacing::{self, Alone, Joint}; use proc_macro::{Group, Ident, Literal, Punct, Span, TokenStream, TokenTree as TT}; +use syn::spanned::Spanned; type Result<T> = core::result::Result<T, TokenStream>; @@ -124,6 +125,22 @@ fn write_with_span(s: Span, mut input: IntoIter, out: &mut TokenStream) -> Resul Ok(()) } +/// Takes an array repeat expression such as `[0_u32; 2]`, and return the tokens with 10 times the +/// original size, which turns to `[0_u32; 20]`. +#[proc_macro] +pub fn make_it_big(input: TokenStream) -> TokenStream { + let mut expr_repeat = syn::parse_macro_input!(input as syn::ExprRepeat); + let len_span = expr_repeat.len.span(); + if let syn::Expr::Lit(expr_lit) = &mut *expr_repeat.len { + if let syn::Lit::Int(lit_int) = &expr_lit.lit { + let orig_val = lit_int.base10_parse::<usize>().expect("not a valid length parameter"); + let new_val = orig_val.saturating_mul(10); + expr_lit.lit = syn::parse_quote_spanned!( len_span => #new_val); + } + } + quote::quote!(#expr_repeat).into() +} + /// Within the item this attribute is attached to, an `inline!` macro is available which expands the /// contained tokens as though they came from a macro expansion. /// diff --git a/tests/ui/large_stack_arrays.rs b/tests/ui/large_stack_arrays.rs index f41423962a1..6bcaf481c9f 100644 --- a/tests/ui/large_stack_arrays.rs +++ b/tests/ui/large_stack_arrays.rs @@ -1,6 +1,9 @@ +//@aux-build:proc_macros.rs #![warn(clippy::large_stack_arrays)] #![allow(clippy::large_enum_variant)] +extern crate proc_macros; + #[derive(Clone, Copy)] struct S { pub data: [u64; 32], @@ -74,12 +77,18 @@ fn issue_12586() { ::std::vec![$($id),*] } } + macro_rules! create_then_move { + ($id:ident; $n:literal) => {{ + let _x_ = [$id; $n]; + //~^ ERROR: allocating a local array larger than 512000 bytes + _x_ + }}; + } let x = [0u32; 50_000]; let y = vec![x, x, x, x, x]; let y = vec![dummy![x, x, x, x, x]]; let y = vec![dummy![[x, x, x, x, x]]]; - //~^ ERROR: allocating a local array larger than 512000 bytes let y = dummy![x, x, x, x, x]; let y = [x, x, dummy!(x), x, x]; //~^ ERROR: allocating a local array larger than 512000 bytes @@ -88,4 +97,9 @@ fn issue_12586() { let y = dummy!(vec![dummy![x, x, x, x, x]]); let y = dummy![[x, x, x, x, x]]; //~^ ERROR: allocating a local array larger than 512000 bytes + + let y = proc_macros::make_it_big!([x; 1]); + //~^ ERROR: allocating a local array larger than 512000 bytes + let y = vec![proc_macros::make_it_big!([x; 10])]; + let y = vec![create_then_move![x; 5]; 5]; } diff --git a/tests/ui/large_stack_arrays.stderr b/tests/ui/large_stack_arrays.stderr index ac4097a463f..06294ee8b8c 100644 --- a/tests/ui/large_stack_arrays.stderr +++ b/tests/ui/large_stack_arrays.stderr @@ -1,5 +1,5 @@ error: allocating a local array larger than 512000 bytes - --> tests/ui/large_stack_arrays.rs:29:14 + --> tests/ui/large_stack_arrays.rs:32:14 | LL | let _x = [build(); 3]; | ^^^^^^^^^^^^ @@ -9,7 +9,7 @@ LL | let _x = [build(); 3]; = help: to override `-D warnings` add `#[allow(clippy::large_stack_arrays)]` error: allocating a local array larger than 512000 bytes - --> tests/ui/large_stack_arrays.rs:32:14 + --> tests/ui/large_stack_arrays.rs:35:14 | LL | let _y = [build(), build(), build()]; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -17,7 +17,7 @@ LL | let _y = [build(), build(), build()]; = help: consider allocating on the heap with `vec![build(), build(), build()].into_boxed_slice()` error: allocating a local array larger than 512000 bytes - --> tests/ui/large_stack_arrays.rs:38:9 + --> tests/ui/large_stack_arrays.rs:41:9 | LL | [0u32; 20_000_000], | ^^^^^^^^^^^^^^^^^^ @@ -25,7 +25,7 @@ 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 - --> tests/ui/large_stack_arrays.rs:40:9 + --> tests/ui/large_stack_arrays.rs:43:9 | LL | [S { data: [0; 32] }; 5000], | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -33,7 +33,7 @@ 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 - --> tests/ui/large_stack_arrays.rs:42:9 + --> tests/ui/large_stack_arrays.rs:45:9 | LL | [Some(""); 20_000_000], | ^^^^^^^^^^^^^^^^^^^^^^ @@ -41,7 +41,7 @@ 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 - --> tests/ui/large_stack_arrays.rs:44:9 + --> tests/ui/large_stack_arrays.rs:47:9 | LL | [E::T(0); 5000], | ^^^^^^^^^^^^^^^ @@ -49,7 +49,7 @@ LL | [E::T(0); 5000], = help: consider allocating on the heap with `vec![E::T(0); 5000].into_boxed_slice()` error: allocating a local array larger than 512000 bytes - --> tests/ui/large_stack_arrays.rs:46:9 + --> tests/ui/large_stack_arrays.rs:49:9 | LL | [0u8; usize::MAX], | ^^^^^^^^^^^^^^^^^ @@ -57,15 +57,7 @@ LL | [0u8; usize::MAX], = help: consider allocating on the heap with `vec![0u8; usize::MAX].into_boxed_slice()` error: allocating a local array larger than 512000 bytes - --> tests/ui/large_stack_arrays.rs:81:25 - | -LL | let y = vec![dummy![[x, x, x, x, x]]]; - | ^^^^^^^^^^^^^^^ - | - = help: consider allocating on the heap with `vec![x, x, x, x, x].into_boxed_slice()` - -error: allocating a local array larger than 512000 bytes - --> tests/ui/large_stack_arrays.rs:84:13 + --> tests/ui/large_stack_arrays.rs:93:13 | LL | let y = [x, x, dummy!(x), x, x]; | ^^^^^^^^^^^^^^^^^^^^^^^ @@ -73,7 +65,7 @@ LL | let y = [x, x, dummy!(x), x, x]; = help: consider allocating on the heap with `vec![x, x, dummy!(x), x, x].into_boxed_slice()` error: allocating a local array larger than 512000 bytes - --> tests/ui/large_stack_arrays.rs:67:13 + --> tests/ui/large_stack_arrays.rs:70:13 | LL | [$a, $b, $a, $b] | ^^^^^^^^^^^^^^^^ @@ -84,12 +76,29 @@ LL | let y = dummy![x => x]; = note: this error originates in the macro `dummy` (in Nightly builds, run with -Z macro-backtrace for more info) error: allocating a local array larger than 512000 bytes - --> tests/ui/large_stack_arrays.rs:89:20 + --> tests/ui/large_stack_arrays.rs:98:20 | LL | let y = dummy![[x, x, x, x, x]]; | ^^^^^^^^^^^^^^^ | = help: consider allocating on the heap with `vec![x, x, x, x, x].into_boxed_slice()` -error: aborting due to 11 previous errors +error: allocating a local array larger than 512000 bytes + --> tests/ui/large_stack_arrays.rs:101:39 + | +LL | let y = proc_macros::make_it_big!([x; 1]); + | ^^^^^^ + +error: allocating a local array larger than 512000 bytes + --> tests/ui/large_stack_arrays.rs:82:23 + | +LL | let _x_ = [$id; $n]; + | ^^^^^^^^^ +... +LL | let y = vec![create_then_move![x; 5]; 5]; + | ----------------------- in this macro invocation + | + = note: this error originates in the macro `create_then_move` (in Nightly builds, run with -Z macro-backtrace for more info) + +error: aborting due to 12 previous errors |