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Commit | Line | Data |
---|---|---|
dfeec247 | 1 | use crate::{LateContext, LateLintPass, LintContext}; |
3dfed10e | 2 | use rustc_ast as ast; |
74b04a01 | 3 | use rustc_attr as attr; |
dfeec247 | 4 | use rustc_data_structures::fx::FxHashSet; |
064997fb | 5 | use rustc_errors::{fluent, Applicability, DiagnosticMessage}; |
dfeec247 | 6 | use rustc_hir as hir; |
94222f64 | 7 | use rustc_hir::{is_range_literal, Expr, ExprKind, Node}; |
064997fb | 8 | use rustc_macros::LintDiagnostic; |
c295e0f8 | 9 | use rustc_middle::ty::layout::{IntegerExt, LayoutOf, SizeSkeleton}; |
ba9703b0 | 10 | use rustc_middle::ty::subst::SubstsRef; |
064997fb | 11 | use rustc_middle::ty::{self, AdtKind, DefIdTree, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable}; |
dfeec247 XL |
12 | use rustc_span::source_map; |
13 | use rustc_span::symbol::sym; | |
2b03887a | 14 | use rustc_span::{Span, Symbol}; |
487cf647 | 15 | use rustc_target::abi::{Abi, Size, WrappingRange}; |
c295e0f8 | 16 | use rustc_target::abi::{Integer, TagEncoding, Variants}; |
3dfed10e | 17 | use rustc_target::spec::abi::Abi as SpecAbi; |
9fa01778 | 18 | |
dfeec247 | 19 | use std::cmp; |
cdc7bbd5 | 20 | use std::iter; |
29967ef6 | 21 | use std::ops::ControlFlow; |
9fa01778 | 22 | |
b039eaaf | 23 | declare_lint! { |
1b1a35ee XL |
24 | /// The `unused_comparisons` lint detects comparisons made useless by |
25 | /// limits of the types involved. | |
26 | /// | |
27 | /// ### Example | |
28 | /// | |
29 | /// ```rust | |
30 | /// fn foo(x: u8) { | |
31 | /// x >= 0; | |
32 | /// } | |
33 | /// ``` | |
34 | /// | |
35 | /// {{produces}} | |
36 | /// | |
37 | /// ### Explanation | |
38 | /// | |
39 | /// A useless comparison may indicate a mistake, and should be fixed or | |
40 | /// removed. | |
b039eaaf SL |
41 | UNUSED_COMPARISONS, |
42 | Warn, | |
43 | "comparisons made useless by limits of the types involved" | |
44 | } | |
45 | ||
46 | declare_lint! { | |
1b1a35ee XL |
47 | /// The `overflowing_literals` lint detects literal out of range for its |
48 | /// type. | |
49 | /// | |
50 | /// ### Example | |
51 | /// | |
52 | /// ```rust,compile_fail | |
53 | /// let x: u8 = 1000; | |
54 | /// ``` | |
55 | /// | |
56 | /// {{produces}} | |
57 | /// | |
58 | /// ### Explanation | |
59 | /// | |
60 | /// It is usually a mistake to use a literal that overflows the type where | |
61 | /// it is used. Either use a literal that is within range, or change the | |
62 | /// type to be within the range of the literal. | |
b039eaaf | 63 | OVERFLOWING_LITERALS, |
9fa01778 XL |
64 | Deny, |
65 | "literal out of range for its type" | |
b039eaaf SL |
66 | } |
67 | ||
5bcae85e | 68 | declare_lint! { |
1b1a35ee XL |
69 | /// The `variant_size_differences` lint detects enums with widely varying |
70 | /// variant sizes. | |
71 | /// | |
72 | /// ### Example | |
73 | /// | |
74 | /// ```rust,compile_fail | |
75 | /// #![deny(variant_size_differences)] | |
76 | /// enum En { | |
77 | /// V0(u8), | |
78 | /// VBig([u8; 1024]), | |
79 | /// } | |
80 | /// ``` | |
81 | /// | |
82 | /// {{produces}} | |
83 | /// | |
84 | /// ### Explanation | |
85 | /// | |
86 | /// It can be a mistake to add a variant to an enum that is much larger | |
87 | /// than the other variants, bloating the overall size required for all | |
88 | /// variants. This can impact performance and memory usage. This is | |
89 | /// triggered if one variant is more than 3 times larger than the | |
90 | /// second-largest variant. | |
91 | /// | |
92 | /// Consider placing the large variant's contents on the heap (for example | |
93 | /// via [`Box`]) to keep the overall size of the enum itself down. | |
94 | /// | |
95 | /// This lint is "allow" by default because it can be noisy, and may not be | |
96 | /// an actual problem. Decisions about this should be guided with | |
97 | /// profiling and benchmarking. | |
98 | /// | |
99 | /// [`Box`]: https://doc.rust-lang.org/std/boxed/index.html | |
5bcae85e SL |
100 | VARIANT_SIZE_DIFFERENCES, |
101 | Allow, | |
102 | "detects enums with widely varying variant sizes" | |
103 | } | |
104 | ||
b039eaaf SL |
105 | #[derive(Copy, Clone)] |
106 | pub struct TypeLimits { | |
107 | /// Id of the last visited negated expression | |
ba9703b0 | 108 | negated_expr_id: Option<hir::HirId>, |
b039eaaf SL |
109 | } |
110 | ||
532ac7d7 XL |
111 | impl_lint_pass!(TypeLimits => [UNUSED_COMPARISONS, OVERFLOWING_LITERALS]); |
112 | ||
b039eaaf SL |
113 | impl TypeLimits { |
114 | pub fn new() -> TypeLimits { | |
ba9703b0 | 115 | TypeLimits { negated_expr_id: None } |
b039eaaf SL |
116 | } |
117 | } | |
118 | ||
2b03887a FG |
119 | /// Attempts to special-case the overflowing literal lint when it occurs as a range endpoint (`expr..MAX+1`). |
120 | /// Returns `true` iff the lint was emitted. | |
f035d41b XL |
121 | fn lint_overflowing_range_endpoint<'tcx>( |
122 | cx: &LateContext<'tcx>, | |
48663c56 XL |
123 | lit: &hir::Lit, |
124 | lit_val: u128, | |
125 | max: u128, | |
dfeec247 | 126 | expr: &'tcx hir::Expr<'tcx>, |
60c5eb7d | 127 | ty: &str, |
48663c56 XL |
128 | ) -> bool { |
129 | // We only want to handle exclusive (`..`) ranges, | |
130 | // which are represented as `ExprKind::Struct`. | |
f2b60f7d FG |
131 | let par_id = cx.tcx.hir().get_parent_node(expr.hir_id); |
132 | let Node::ExprField(field) = cx.tcx.hir().get(par_id) else { return false }; | |
133 | let field_par_id = cx.tcx.hir().get_parent_node(field.hir_id); | |
134 | let Node::Expr(struct_expr) = cx.tcx.hir().get(field_par_id) else { return false }; | |
135 | if !is_range_literal(struct_expr) { | |
136 | return false; | |
137 | }; | |
138 | let ExprKind::Struct(_, eps, _) = &struct_expr.kind else { return false }; | |
139 | if eps.len() != 2 { | |
140 | return false; | |
141 | } | |
142 | ||
f2b60f7d FG |
143 | // We can suggest using an inclusive range |
144 | // (`..=`) instead only if it is the `end` that is | |
145 | // overflowing and only by 1. | |
2b03887a FG |
146 | if !(eps[1].expr.hir_id == expr.hir_id && lit_val - 1 == max) { |
147 | return false; | |
148 | }; | |
149 | let Ok(start) = cx.sess().source_map().span_to_snippet(eps[0].span) else { return false }; | |
150 | ||
151 | cx.struct_span_lint( | |
152 | OVERFLOWING_LITERALS, | |
153 | struct_expr.span, | |
154 | fluent::lint_range_endpoint_out_of_range, | |
155 | |lint| { | |
156 | use ast::{LitIntType, LitKind}; | |
157 | ||
158 | lint.set_arg("ty", ty); | |
159 | ||
160 | // We need to preserve the literal's suffix, | |
161 | // as it may determine typing information. | |
162 | let suffix = match lit.node { | |
163 | LitKind::Int(_, LitIntType::Signed(s)) => s.name_str(), | |
164 | LitKind::Int(_, LitIntType::Unsigned(s)) => s.name_str(), | |
165 | LitKind::Int(_, LitIntType::Unsuffixed) => "", | |
166 | _ => bug!(), | |
167 | }; | |
168 | let suggestion = format!("{}..={}{}", start, lit_val - 1, suffix); | |
169 | lint.span_suggestion( | |
170 | struct_expr.span, | |
171 | fluent::suggestion, | |
172 | suggestion, | |
173 | Applicability::MachineApplicable, | |
174 | ); | |
175 | ||
176 | lint | |
177 | }, | |
178 | ); | |
179 | ||
180 | // We've just emitted a lint, special cased for `(...)..MAX+1` ranges, | |
181 | // return `true` so the callers don't also emit a lint | |
182 | true | |
48663c56 XL |
183 | } |
184 | ||
185 | // For `isize` & `usize`, be conservative with the warnings, so that the | |
186 | // warnings are consistent between 32- and 64-bit platforms. | |
5869c6ff | 187 | fn int_ty_range(int_ty: ty::IntTy) -> (i128, i128) { |
48663c56 | 188 | match int_ty { |
5869c6ff XL |
189 | ty::IntTy::Isize => (i64::MIN.into(), i64::MAX.into()), |
190 | ty::IntTy::I8 => (i8::MIN.into(), i8::MAX.into()), | |
191 | ty::IntTy::I16 => (i16::MIN.into(), i16::MAX.into()), | |
192 | ty::IntTy::I32 => (i32::MIN.into(), i32::MAX.into()), | |
193 | ty::IntTy::I64 => (i64::MIN.into(), i64::MAX.into()), | |
194 | ty::IntTy::I128 => (i128::MIN, i128::MAX), | |
48663c56 XL |
195 | } |
196 | } | |
197 | ||
5869c6ff | 198 | fn uint_ty_range(uint_ty: ty::UintTy) -> (u128, u128) { |
29967ef6 | 199 | let max = match uint_ty { |
5869c6ff XL |
200 | ty::UintTy::Usize => u64::MAX.into(), |
201 | ty::UintTy::U8 => u8::MAX.into(), | |
202 | ty::UintTy::U16 => u16::MAX.into(), | |
203 | ty::UintTy::U32 => u32::MAX.into(), | |
204 | ty::UintTy::U64 => u64::MAX.into(), | |
205 | ty::UintTy::U128 => u128::MAX, | |
29967ef6 XL |
206 | }; |
207 | (0, max) | |
48663c56 XL |
208 | } |
209 | ||
f035d41b | 210 | fn get_bin_hex_repr(cx: &LateContext<'_>, lit: &hir::Lit) -> Option<String> { |
48663c56 XL |
211 | let src = cx.sess().source_map().span_to_snippet(lit.span).ok()?; |
212 | let firstch = src.chars().next()?; | |
213 | ||
214 | if firstch == '0' { | |
215 | match src.chars().nth(1) { | |
ba9703b0 | 216 | Some('x' | 'b') => return Some(src), |
48663c56 XL |
217 | _ => return None, |
218 | } | |
219 | } | |
220 | ||
221 | None | |
222 | } | |
223 | ||
224 | fn report_bin_hex_error( | |
f035d41b | 225 | cx: &LateContext<'_>, |
dfeec247 | 226 | expr: &hir::Expr<'_>, |
48663c56 | 227 | ty: attr::IntType, |
487cf647 | 228 | size: Size, |
48663c56 XL |
229 | repr_str: String, |
230 | val: u128, | |
231 | negative: bool, | |
232 | ) { | |
2b03887a FG |
233 | cx.struct_span_lint( |
234 | OVERFLOWING_LITERALS, | |
235 | expr.span, | |
236 | fluent::lint_overflowing_bin_hex, | |
237 | |lint| { | |
238 | let (t, actually) = match ty { | |
239 | attr::IntType::SignedInt(t) => { | |
240 | let actually = if negative { | |
241 | -(size.sign_extend(val) as i128) | |
242 | } else { | |
243 | size.sign_extend(val) as i128 | |
244 | }; | |
245 | (t.name_str(), actually.to_string()) | |
246 | } | |
247 | attr::IntType::UnsignedInt(t) => { | |
248 | let actually = size.truncate(val); | |
249 | (t.name_str(), actually.to_string()) | |
250 | } | |
251 | }; | |
252 | ||
253 | if negative { | |
254 | // If the value is negative, | |
255 | // emits a note about the value itself, apart from the literal. | |
256 | lint.note(fluent::negative_note); | |
257 | lint.note(fluent::negative_becomes_note); | |
74b04a01 | 258 | } else { |
2b03887a | 259 | lint.note(fluent::positive_note); |
74b04a01 | 260 | } |
2b03887a FG |
261 | if let Some(sugg_ty) = |
262 | get_type_suggestion(cx.typeck_results().node_type(expr.hir_id), val, negative) | |
263 | { | |
264 | lint.set_arg("suggestion_ty", sugg_ty); | |
265 | if let Some(pos) = repr_str.chars().position(|c| c == 'i' || c == 'u') { | |
266 | let (sans_suffix, _) = repr_str.split_at(pos); | |
267 | lint.span_suggestion( | |
268 | expr.span, | |
269 | fluent::suggestion, | |
270 | format!("{}{}", sans_suffix, sugg_ty), | |
271 | Applicability::MachineApplicable, | |
272 | ); | |
273 | } else { | |
274 | lint.help(fluent::help); | |
275 | } | |
276 | } | |
277 | lint.set_arg("ty", t) | |
278 | .set_arg("lit", repr_str) | |
279 | .set_arg("dec", val) | |
280 | .set_arg("actually", actually); | |
281 | ||
282 | lint | |
283 | }, | |
284 | ); | |
48663c56 XL |
285 | } |
286 | ||
287 | // This function finds the next fitting type and generates a suggestion string. | |
288 | // It searches for fitting types in the following way (`X < Y`): | |
289 | // - `iX`: if literal fits in `uX` => `uX`, else => `iY` | |
290 | // - `-iX` => `iY` | |
291 | // - `uX` => `uY` | |
292 | // | |
293 | // No suggestion for: `isize`, `usize`. | |
60c5eb7d | 294 | fn get_type_suggestion(t: Ty<'_>, val: u128, negative: bool) -> Option<&'static str> { |
5869c6ff XL |
295 | use ty::IntTy::*; |
296 | use ty::UintTy::*; | |
48663c56 XL |
297 | macro_rules! find_fit { |
298 | ($ty:expr, $val:expr, $negative:expr, | |
299 | $($type:ident => [$($utypes:expr),*] => [$($itypes:expr),*]),+) => { | |
300 | { | |
301 | let _neg = if negative { 1 } else { 0 }; | |
302 | match $ty { | |
303 | $($type => { | |
304 | $(if !negative && val <= uint_ty_range($utypes).1 { | |
60c5eb7d | 305 | return Some($utypes.name_str()) |
48663c56 XL |
306 | })* |
307 | $(if val <= int_ty_range($itypes).1 as u128 + _neg { | |
60c5eb7d | 308 | return Some($itypes.name_str()) |
48663c56 XL |
309 | })* |
310 | None | |
dc9dc135 | 311 | },)+ |
48663c56 XL |
312 | _ => None |
313 | } | |
314 | } | |
315 | } | |
316 | } | |
1b1a35ee | 317 | match t.kind() { |
48663c56 XL |
318 | ty::Int(i) => find_fit!(i, val, negative, |
319 | I8 => [U8] => [I16, I32, I64, I128], | |
320 | I16 => [U16] => [I32, I64, I128], | |
321 | I32 => [U32] => [I64, I128], | |
322 | I64 => [U64] => [I128], | |
323 | I128 => [U128] => []), | |
324 | ty::Uint(u) => find_fit!(u, val, negative, | |
325 | U8 => [U8, U16, U32, U64, U128] => [], | |
326 | U16 => [U16, U32, U64, U128] => [], | |
327 | U32 => [U32, U64, U128] => [], | |
328 | U64 => [U64, U128] => [], | |
329 | U128 => [U128] => []), | |
330 | _ => None, | |
331 | } | |
332 | } | |
333 | ||
f035d41b XL |
334 | fn lint_int_literal<'tcx>( |
335 | cx: &LateContext<'tcx>, | |
48663c56 | 336 | type_limits: &TypeLimits, |
dfeec247 | 337 | e: &'tcx hir::Expr<'tcx>, |
48663c56 | 338 | lit: &hir::Lit, |
5869c6ff | 339 | t: ty::IntTy, |
48663c56 XL |
340 | v: u128, |
341 | ) { | |
29967ef6 | 342 | let int_type = t.normalize(cx.sess().target.pointer_width); |
ba9703b0 | 343 | let (min, max) = int_ty_range(int_type); |
48663c56 | 344 | let max = max as u128; |
ba9703b0 | 345 | let negative = type_limits.negated_expr_id == Some(e.hir_id); |
48663c56 XL |
346 | |
347 | // Detect literal value out of range [min, max] inclusive | |
348 | // avoiding use of -min to prevent overflow/panic | |
349 | if (negative && v > max + 1) || (!negative && v > max) { | |
350 | if let Some(repr_str) = get_bin_hex_repr(cx, lit) { | |
5869c6ff XL |
351 | report_bin_hex_error( |
352 | cx, | |
353 | e, | |
354 | attr::IntType::SignedInt(ty::ast_int_ty(t)), | |
487cf647 | 355 | Integer::from_int_ty(cx, t).size(), |
5869c6ff XL |
356 | repr_str, |
357 | v, | |
358 | negative, | |
359 | ); | |
48663c56 XL |
360 | return; |
361 | } | |
362 | ||
f2b60f7d | 363 | if lint_overflowing_range_endpoint(cx, lit, v, max, e, t.name_str()) { |
487cf647 | 364 | // The overflowing literal lint was emitted by `lint_overflowing_range_endpoint`. |
f2b60f7d | 365 | return; |
48663c56 XL |
366 | } |
367 | ||
2b03887a FG |
368 | cx.struct_span_lint(OVERFLOWING_LITERALS, e.span, fluent::lint_overflowing_int, |lint| { |
369 | lint.set_arg("ty", t.name_str()) | |
370 | .set_arg( | |
371 | "lit", | |
372 | cx.sess() | |
373 | .source_map() | |
374 | .span_to_snippet(lit.span) | |
375 | .expect("must get snippet from literal"), | |
376 | ) | |
377 | .set_arg("min", min) | |
378 | .set_arg("max", max) | |
379 | .note(fluent::note); | |
380 | ||
6a06907d | 381 | if let Some(sugg_ty) = |
5099ac24 | 382 | get_type_suggestion(cx.typeck_results().node_type(e.hir_id), v, negative) |
6a06907d | 383 | { |
2b03887a FG |
384 | lint.set_arg("suggestion_ty", sugg_ty); |
385 | lint.help(fluent::help); | |
6a06907d | 386 | } |
2b03887a FG |
387 | |
388 | lint | |
74b04a01 | 389 | }); |
48663c56 XL |
390 | } |
391 | } | |
392 | ||
f035d41b XL |
393 | fn lint_uint_literal<'tcx>( |
394 | cx: &LateContext<'tcx>, | |
dfeec247 | 395 | e: &'tcx hir::Expr<'tcx>, |
48663c56 | 396 | lit: &hir::Lit, |
5869c6ff | 397 | t: ty::UintTy, |
48663c56 | 398 | ) { |
29967ef6 | 399 | let uint_type = t.normalize(cx.sess().target.pointer_width); |
48663c56 XL |
400 | let (min, max) = uint_ty_range(uint_type); |
401 | let lit_val: u128 = match lit.node { | |
402 | // _v is u8, within range by definition | |
403 | ast::LitKind::Byte(_v) => return, | |
404 | ast::LitKind::Int(v, _) => v, | |
405 | _ => bug!(), | |
406 | }; | |
407 | if lit_val < min || lit_val > max { | |
dc9dc135 XL |
408 | let parent_id = cx.tcx.hir().get_parent_node(e.hir_id); |
409 | if let Node::Expr(par_e) = cx.tcx.hir().get(parent_id) { | |
e74abb32 | 410 | match par_e.kind { |
48663c56 | 411 | hir::ExprKind::Cast(..) => { |
1b1a35ee | 412 | if let ty::Char = cx.typeck_results().expr_ty(par_e).kind() { |
2b03887a FG |
413 | cx.struct_span_lint( |
414 | OVERFLOWING_LITERALS, | |
415 | par_e.span, | |
416 | fluent::lint_only_cast_u8_to_char, | |
417 | |lint| { | |
418 | lint.span_suggestion( | |
74b04a01 | 419 | par_e.span, |
2b03887a | 420 | fluent::suggestion, |
74b04a01 XL |
421 | format!("'\\u{{{:X}}}'", lit_val), |
422 | Applicability::MachineApplicable, | |
423 | ) | |
2b03887a FG |
424 | }, |
425 | ); | |
48663c56 XL |
426 | return; |
427 | } | |
428 | } | |
48663c56 XL |
429 | _ => {} |
430 | } | |
431 | } | |
f2b60f7d | 432 | if lint_overflowing_range_endpoint(cx, lit, lit_val, max, e, t.name_str()) { |
487cf647 | 433 | // The overflowing literal lint was emitted by `lint_overflowing_range_endpoint`. |
f2b60f7d FG |
434 | return; |
435 | } | |
48663c56 | 436 | if let Some(repr_str) = get_bin_hex_repr(cx, lit) { |
5869c6ff XL |
437 | report_bin_hex_error( |
438 | cx, | |
439 | e, | |
440 | attr::IntType::UnsignedInt(ty::ast_uint_ty(t)), | |
487cf647 | 441 | Integer::from_uint_ty(cx, t).size(), |
5869c6ff XL |
442 | repr_str, |
443 | lit_val, | |
444 | false, | |
445 | ); | |
48663c56 XL |
446 | return; |
447 | } | |
2b03887a FG |
448 | cx.struct_span_lint(OVERFLOWING_LITERALS, e.span, fluent::lint_overflowing_uint, |lint| { |
449 | lint.set_arg("ty", t.name_str()) | |
064997fb FG |
450 | .set_arg( |
451 | "lit", | |
ba9703b0 XL |
452 | cx.sess() |
453 | .source_map() | |
454 | .span_to_snippet(lit.span) | |
455 | .expect("must get snippet from literal"), | |
064997fb FG |
456 | ) |
457 | .set_arg("min", min) | |
458 | .set_arg("max", max) | |
2b03887a | 459 | .note(fluent::note) |
74b04a01 | 460 | }); |
48663c56 XL |
461 | } |
462 | } | |
463 | ||
f035d41b XL |
464 | fn lint_literal<'tcx>( |
465 | cx: &LateContext<'tcx>, | |
48663c56 | 466 | type_limits: &TypeLimits, |
dfeec247 | 467 | e: &'tcx hir::Expr<'tcx>, |
48663c56 XL |
468 | lit: &hir::Lit, |
469 | ) { | |
1b1a35ee | 470 | match *cx.typeck_results().node_type(e.hir_id).kind() { |
48663c56 XL |
471 | ty::Int(t) => { |
472 | match lit.node { | |
ba9703b0 | 473 | ast::LitKind::Int(v, ast::LitIntType::Signed(_) | ast::LitIntType::Unsuffixed) => { |
48663c56 XL |
474 | lint_int_literal(cx, type_limits, e, lit, t, v) |
475 | } | |
476 | _ => bug!(), | |
477 | }; | |
478 | } | |
dfeec247 | 479 | ty::Uint(t) => lint_uint_literal(cx, e, lit, t), |
48663c56 XL |
480 | ty::Float(t) => { |
481 | let is_infinite = match lit.node { | |
dfeec247 | 482 | ast::LitKind::Float(v, _) => match t { |
5869c6ff XL |
483 | ty::FloatTy::F32 => v.as_str().parse().map(f32::is_infinite), |
484 | ty::FloatTy::F64 => v.as_str().parse().map(f64::is_infinite), | |
dfeec247 | 485 | }, |
48663c56 XL |
486 | _ => bug!(), |
487 | }; | |
488 | if is_infinite == Ok(true) { | |
2b03887a FG |
489 | cx.struct_span_lint( |
490 | OVERFLOWING_LITERALS, | |
491 | e.span, | |
492 | fluent::lint_overflowing_literal, | |
493 | |lint| { | |
494 | lint.set_arg("ty", t.name_str()) | |
495 | .set_arg( | |
496 | "lit", | |
497 | cx.sess() | |
498 | .source_map() | |
499 | .span_to_snippet(lit.span) | |
500 | .expect("must get snippet from literal"), | |
501 | ) | |
502 | .note(fluent::note) | |
503 | }, | |
504 | ); | |
48663c56 XL |
505 | } |
506 | } | |
507 | _ => {} | |
508 | } | |
509 | } | |
510 | ||
f035d41b XL |
511 | impl<'tcx> LateLintPass<'tcx> for TypeLimits { |
512 | fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx hir::Expr<'tcx>) { | |
e74abb32 | 513 | match e.kind { |
6a06907d | 514 | hir::ExprKind::Unary(hir::UnOp::Neg, ref expr) => { |
b039eaaf | 515 | // propagate negation, if the negation itself isn't negated |
ba9703b0 XL |
516 | if self.negated_expr_id != Some(e.hir_id) { |
517 | self.negated_expr_id = Some(expr.hir_id); | |
b039eaaf | 518 | } |
c30ab7b3 | 519 | } |
8faf50e0 | 520 | hir::ExprKind::Binary(binop, ref l, ref r) => { |
32a655c1 | 521 | if is_comparison(binop) && !check_limits(cx, binop, &l, &r) { |
2b03887a FG |
522 | cx.struct_span_lint( |
523 | UNUSED_COMPARISONS, | |
524 | e.span, | |
525 | fluent::lint_unused_comparisons, | |
526 | |lint| lint, | |
527 | ); | |
b039eaaf | 528 | } |
c30ab7b3 | 529 | } |
48663c56 XL |
530 | hir::ExprKind::Lit(ref lit) => lint_literal(cx, self, e, lit), |
531 | _ => {} | |
b039eaaf SL |
532 | }; |
533 | ||
c30ab7b3 | 534 | fn is_valid<T: cmp::PartialOrd>(binop: hir::BinOp, v: T, min: T, max: T) -> bool { |
b039eaaf | 535 | match binop.node { |
8faf50e0 XL |
536 | hir::BinOpKind::Lt => v > min && v <= max, |
537 | hir::BinOpKind::Le => v >= min && v < max, | |
538 | hir::BinOpKind::Gt => v >= min && v < max, | |
539 | hir::BinOpKind::Ge => v > min && v <= max, | |
540 | hir::BinOpKind::Eq | hir::BinOpKind::Ne => v >= min && v <= max, | |
c30ab7b3 | 541 | _ => bug!(), |
b039eaaf SL |
542 | } |
543 | } | |
544 | ||
545 | fn rev_binop(binop: hir::BinOp) -> hir::BinOp { | |
dfeec247 XL |
546 | source_map::respan( |
547 | binop.span, | |
548 | match binop.node { | |
549 | hir::BinOpKind::Lt => hir::BinOpKind::Gt, | |
550 | hir::BinOpKind::Le => hir::BinOpKind::Ge, | |
551 | hir::BinOpKind::Gt => hir::BinOpKind::Lt, | |
552 | hir::BinOpKind::Ge => hir::BinOpKind::Le, | |
553 | _ => return binop, | |
554 | }, | |
555 | ) | |
b039eaaf SL |
556 | } |
557 | ||
dfeec247 | 558 | fn check_limits( |
f035d41b | 559 | cx: &LateContext<'_>, |
dfeec247 XL |
560 | binop: hir::BinOp, |
561 | l: &hir::Expr<'_>, | |
562 | r: &hir::Expr<'_>, | |
563 | ) -> bool { | |
e74abb32 | 564 | let (lit, expr, swap) = match (&l.kind, &r.kind) { |
8faf50e0 XL |
565 | (&hir::ExprKind::Lit(_), _) => (l, r, true), |
566 | (_, &hir::ExprKind::Lit(_)) => (r, l, false), | |
c30ab7b3 | 567 | _ => return true, |
b039eaaf SL |
568 | }; |
569 | // Normalize the binop so that the literal is always on the RHS in | |
570 | // the comparison | |
c30ab7b3 | 571 | let norm_binop = if swap { rev_binop(binop) } else { binop }; |
1b1a35ee | 572 | match *cx.typeck_results().node_type(expr.hir_id).kind() { |
b7449926 | 573 | ty::Int(int_ty) => { |
b039eaaf | 574 | let (min, max) = int_ty_range(int_ty); |
e74abb32 | 575 | let lit_val: i128 = match lit.kind { |
dfeec247 | 576 | hir::ExprKind::Lit(ref li) => match li.node { |
ba9703b0 XL |
577 | ast::LitKind::Int( |
578 | v, | |
579 | ast::LitIntType::Signed(_) | ast::LitIntType::Unsuffixed, | |
580 | ) => v as i128, | |
dfeec247 | 581 | _ => return true, |
32a655c1 | 582 | }, |
dfeec247 | 583 | _ => bug!(), |
b039eaaf SL |
584 | }; |
585 | is_valid(norm_binop, lit_val, min, max) | |
586 | } | |
b7449926 | 587 | ty::Uint(uint_ty) => { |
dfeec247 | 588 | let (min, max): (u128, u128) = uint_ty_range(uint_ty); |
e74abb32 | 589 | let lit_val: u128 = match lit.kind { |
dfeec247 XL |
590 | hir::ExprKind::Lit(ref li) => match li.node { |
591 | ast::LitKind::Int(v, _) => v, | |
592 | _ => return true, | |
32a655c1 | 593 | }, |
dfeec247 | 594 | _ => bug!(), |
b039eaaf SL |
595 | }; |
596 | is_valid(norm_binop, lit_val, min, max) | |
597 | } | |
c30ab7b3 | 598 | _ => true, |
b039eaaf SL |
599 | } |
600 | } | |
601 | ||
602 | fn is_comparison(binop: hir::BinOp) -> bool { | |
29967ef6 XL |
603 | matches!( |
604 | binop.node, | |
dfeec247 | 605 | hir::BinOpKind::Eq |
29967ef6 XL |
606 | | hir::BinOpKind::Lt |
607 | | hir::BinOpKind::Le | |
608 | | hir::BinOpKind::Ne | |
609 | | hir::BinOpKind::Ge | |
610 | | hir::BinOpKind::Gt | |
611 | ) | |
b039eaaf | 612 | } |
b039eaaf SL |
613 | } |
614 | } | |
615 | ||
616 | declare_lint! { | |
1b1a35ee XL |
617 | /// The `improper_ctypes` lint detects incorrect use of types in foreign |
618 | /// modules. | |
619 | /// | |
620 | /// ### Example | |
621 | /// | |
622 | /// ```rust | |
623 | /// extern "C" { | |
624 | /// static STATIC: String; | |
625 | /// } | |
626 | /// ``` | |
627 | /// | |
628 | /// {{produces}} | |
629 | /// | |
630 | /// ### Explanation | |
631 | /// | |
632 | /// The compiler has several checks to verify that types used in `extern` | |
633 | /// blocks are safe and follow certain rules to ensure proper | |
634 | /// compatibility with the foreign interfaces. This lint is issued when it | |
635 | /// detects a probable mistake in a definition. The lint usually should | |
636 | /// provide a description of the issue, along with possibly a hint on how | |
637 | /// to resolve it. | |
b039eaaf SL |
638 | IMPROPER_CTYPES, |
639 | Warn, | |
640 | "proper use of libc types in foreign modules" | |
641 | } | |
642 | ||
f035d41b XL |
643 | declare_lint_pass!(ImproperCTypesDeclarations => [IMPROPER_CTYPES]); |
644 | ||
645 | declare_lint! { | |
1b1a35ee XL |
646 | /// The `improper_ctypes_definitions` lint detects incorrect use of |
647 | /// [`extern` function] definitions. | |
648 | /// | |
649 | /// [`extern` function]: https://doc.rust-lang.org/reference/items/functions.html#extern-function-qualifier | |
650 | /// | |
651 | /// ### Example | |
652 | /// | |
653 | /// ```rust | |
654 | /// # #![allow(unused)] | |
655 | /// pub extern "C" fn str_type(p: &str) { } | |
656 | /// ``` | |
657 | /// | |
658 | /// {{produces}} | |
659 | /// | |
660 | /// ### Explanation | |
661 | /// | |
662 | /// There are many parameter and return types that may be specified in an | |
663 | /// `extern` function that are not compatible with the given ABI. This | |
664 | /// lint is an alert that these types should not be used. The lint usually | |
665 | /// should provide a description of the issue, along with possibly a hint | |
666 | /// on how to resolve it. | |
f035d41b XL |
667 | IMPROPER_CTYPES_DEFINITIONS, |
668 | Warn, | |
669 | "proper use of libc types in foreign item definitions" | |
670 | } | |
671 | ||
672 | declare_lint_pass!(ImproperCTypesDefinitions => [IMPROPER_CTYPES_DEFINITIONS]); | |
673 | ||
3dfed10e | 674 | #[derive(Clone, Copy)] |
923072b8 | 675 | pub(crate) enum CItemKind { |
3dfed10e XL |
676 | Declaration, |
677 | Definition, | |
f035d41b | 678 | } |
532ac7d7 | 679 | |
dc9dc135 | 680 | struct ImproperCTypesVisitor<'a, 'tcx> { |
f035d41b | 681 | cx: &'a LateContext<'tcx>, |
3dfed10e | 682 | mode: CItemKind, |
b039eaaf SL |
683 | } |
684 | ||
0531ce1d | 685 | enum FfiResult<'tcx> { |
b039eaaf | 686 | FfiSafe, |
0531ce1d | 687 | FfiPhantom(Ty<'tcx>), |
064997fb | 688 | FfiUnsafe { ty: Ty<'tcx>, reason: DiagnosticMessage, help: Option<DiagnosticMessage> }, |
b039eaaf SL |
689 | } |
690 | ||
923072b8 FG |
691 | pub(crate) fn nonnull_optimization_guaranteed<'tcx>( |
692 | tcx: TyCtxt<'tcx>, | |
693 | def: ty::AdtDef<'tcx>, | |
694 | ) -> bool { | |
04454e1e | 695 | tcx.has_attr(def.did(), sym::rustc_nonnull_optimization_guaranteed) |
1b1a35ee XL |
696 | } |
697 | ||
698 | /// `repr(transparent)` structs can have a single non-ZST field, this function returns that | |
699 | /// field. | |
700 | pub fn transparent_newtype_field<'a, 'tcx>( | |
701 | tcx: TyCtxt<'tcx>, | |
702 | variant: &'a ty::VariantDef, | |
703 | ) -> Option<&'a ty::FieldDef> { | |
704 | let param_env = tcx.param_env(variant.def_id); | |
17df50a5 | 705 | variant.fields.iter().find(|field| { |
1b1a35ee | 706 | let field_ty = tcx.type_of(field.did); |
5869c6ff | 707 | let is_zst = tcx.layout_of(param_env.and(field_ty)).map_or(false, |layout| layout.is_zst()); |
17df50a5 XL |
708 | !is_zst |
709 | }) | |
1b1a35ee XL |
710 | } |
711 | ||
3dfed10e | 712 | /// Is type known to be non-null? |
6a06907d | 713 | fn ty_is_known_nonnull<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>, mode: CItemKind) -> bool { |
3dfed10e | 714 | let tcx = cx.tcx; |
1b1a35ee | 715 | match ty.kind() { |
3dfed10e XL |
716 | ty::FnPtr(_) => true, |
717 | ty::Ref(..) => true, | |
718 | ty::Adt(def, _) if def.is_box() && matches!(mode, CItemKind::Definition) => true, | |
5e7ed085 FG |
719 | ty::Adt(def, substs) if def.repr().transparent() && !def.is_union() => { |
720 | let marked_non_null = nonnull_optimization_guaranteed(tcx, *def); | |
3dfed10e | 721 | |
1b1a35ee | 722 | if marked_non_null { |
3dfed10e | 723 | return true; |
f9652781 | 724 | } |
1b1a35ee | 725 | |
064997fb FG |
726 | // `UnsafeCell` has its niche hidden. |
727 | if def.is_unsafe_cell() { | |
6a06907d XL |
728 | return false; |
729 | } | |
730 | ||
5e7ed085 | 731 | def.variants() |
17df50a5 XL |
732 | .iter() |
733 | .filter_map(|variant| transparent_newtype_field(cx.tcx, variant)) | |
734 | .any(|field| ty_is_known_nonnull(cx, field.ty(tcx, substs), mode)) | |
b039eaaf | 735 | } |
3dfed10e | 736 | _ => false, |
b039eaaf | 737 | } |
3dfed10e | 738 | } |
dc9dc135 | 739 | |
3dfed10e XL |
740 | /// Given a non-null scalar (or transparent) type `ty`, return the nullable version of that type. |
741 | /// If the type passed in was not scalar, returns None. | |
742 | fn get_nullable_type<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'tcx>> { | |
743 | let tcx = cx.tcx; | |
1b1a35ee | 744 | Some(match *ty.kind() { |
3dfed10e XL |
745 | ty::Adt(field_def, field_substs) => { |
746 | let inner_field_ty = { | |
f2b60f7d | 747 | let mut first_non_zst_ty = field_def |
5e7ed085 FG |
748 | .variants() |
749 | .iter() | |
750 | .filter_map(|v| transparent_newtype_field(cx.tcx, v)); | |
3dfed10e XL |
751 | debug_assert_eq!( |
752 | first_non_zst_ty.clone().count(), | |
753 | 1, | |
754 | "Wrong number of fields for transparent type" | |
755 | ); | |
756 | first_non_zst_ty | |
f2b60f7d | 757 | .next_back() |
3dfed10e XL |
758 | .expect("No non-zst fields in transparent type.") |
759 | .ty(tcx, field_substs) | |
760 | }; | |
761 | return get_nullable_type(cx, inner_field_ty); | |
762 | } | |
763 | ty::Int(ty) => tcx.mk_mach_int(ty), | |
764 | ty::Uint(ty) => tcx.mk_mach_uint(ty), | |
765 | ty::RawPtr(ty_mut) => tcx.mk_ptr(ty_mut), | |
766 | // As these types are always non-null, the nullable equivalent of | |
767 | // Option<T> of these types are their raw pointer counterparts. | |
768 | ty::Ref(_region, ty, mutbl) => tcx.mk_ptr(ty::TypeAndMut { ty, mutbl }), | |
769 | ty::FnPtr(..) => { | |
770 | // There is no nullable equivalent for Rust's function pointers -- you | |
771 | // must use an Option<fn(..) -> _> to represent it. | |
772 | ty | |
773 | } | |
774 | ||
775 | // We should only ever reach this case if ty_is_known_nonnull is extended | |
776 | // to other types. | |
777 | ref unhandled => { | |
778 | debug!( | |
779 | "get_nullable_type: Unhandled scalar kind: {:?} while checking {:?}", | |
780 | unhandled, ty | |
781 | ); | |
782 | return None; | |
783 | } | |
784 | }) | |
785 | } | |
786 | ||
787 | /// Check if this enum can be safely exported based on the "nullable pointer optimization". If it | |
1b1a35ee | 788 | /// can, return the type that `ty` can be safely converted to, otherwise return `None`. |
3dfed10e XL |
789 | /// Currently restricted to function pointers, boxes, references, `core::num::NonZero*`, |
790 | /// `core::ptr::NonNull`, and `#[repr(transparent)]` newtypes. | |
791 | /// FIXME: This duplicates code in codegen. | |
923072b8 | 792 | pub(crate) fn repr_nullable_ptr<'tcx>( |
3dfed10e XL |
793 | cx: &LateContext<'tcx>, |
794 | ty: Ty<'tcx>, | |
795 | ckind: CItemKind, | |
796 | ) -> Option<Ty<'tcx>> { | |
797 | debug!("is_repr_nullable_ptr(cx, ty = {:?})", ty); | |
1b1a35ee | 798 | if let ty::Adt(ty_def, substs) = ty.kind() { |
5e7ed085 | 799 | let field_ty = match &ty_def.variants().raw[..] { |
17df50a5 XL |
800 | [var_one, var_two] => match (&var_one.fields[..], &var_two.fields[..]) { |
801 | ([], [field]) | ([field], []) => field.ty(cx.tcx, substs), | |
802 | _ => return None, | |
803 | }, | |
804 | _ => return None, | |
f035d41b | 805 | }; |
dc9dc135 | 806 | |
3dfed10e XL |
807 | if !ty_is_known_nonnull(cx, field_ty, ckind) { |
808 | return None; | |
f035d41b | 809 | } |
dc9dc135 | 810 | |
3dfed10e XL |
811 | // At this point, the field's type is known to be nonnull and the parent enum is Option-like. |
812 | // If the computed size for the field and the enum are different, the nonnull optimization isn't | |
813 | // being applied (and we've got a problem somewhere). | |
814 | let compute_size_skeleton = |t| SizeSkeleton::compute(t, cx.tcx, cx.param_env).unwrap(); | |
f035d41b XL |
815 | if !compute_size_skeleton(ty).same_size(compute_size_skeleton(field_ty)) { |
816 | bug!("improper_ctypes: Option nonnull optimization not applied?"); | |
817 | } | |
dc9dc135 | 818 | |
3dfed10e XL |
819 | // Return the nullable type this Option-like enum can be safely represented with. |
820 | let field_ty_abi = &cx.layout_of(field_ty).unwrap().abi; | |
821 | if let Abi::Scalar(field_ty_scalar) = field_ty_abi { | |
04454e1e FG |
822 | match field_ty_scalar.valid_range(cx) { |
823 | WrappingRange { start: 0, end } | |
824 | if end == field_ty_scalar.size(&cx.tcx).unsigned_int_max() - 1 => | |
825 | { | |
5e7ed085 FG |
826 | return Some(get_nullable_type(cx, field_ty).unwrap()); |
827 | } | |
04454e1e | 828 | WrappingRange { start: 1, .. } => { |
3dfed10e XL |
829 | return Some(get_nullable_type(cx, field_ty).unwrap()); |
830 | } | |
04454e1e FG |
831 | WrappingRange { start, end } => { |
832 | unreachable!("Unhandled start and end range: ({}, {})", start, end) | |
833 | } | |
3dfed10e XL |
834 | }; |
835 | } | |
f035d41b | 836 | } |
3dfed10e XL |
837 | None |
838 | } | |
b039eaaf | 839 | |
3dfed10e | 840 | impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { |
60c5eb7d XL |
841 | /// Check if the type is array and emit an unsafe type lint. |
842 | fn check_for_array_ty(&mut self, sp: Span, ty: Ty<'tcx>) -> bool { | |
1b1a35ee | 843 | if let ty::Array(..) = ty.kind() { |
60c5eb7d XL |
844 | self.emit_ffi_unsafe_type_lint( |
845 | ty, | |
846 | sp, | |
2b03887a FG |
847 | fluent::lint_improper_ctypes_array_reason, |
848 | Some(fluent::lint_improper_ctypes_array_help), | |
60c5eb7d XL |
849 | ); |
850 | true | |
851 | } else { | |
852 | false | |
853 | } | |
854 | } | |
855 | ||
f035d41b XL |
856 | /// Checks if the given field's type is "ffi-safe". |
857 | fn check_field_type_for_ffi( | |
858 | &self, | |
859 | cache: &mut FxHashSet<Ty<'tcx>>, | |
860 | field: &ty::FieldDef, | |
861 | substs: SubstsRef<'tcx>, | |
862 | ) -> FfiResult<'tcx> { | |
863 | let field_ty = field.ty(self.cx.tcx, substs); | |
864 | if field_ty.has_opaque_types() { | |
865 | self.check_type_for_ffi(cache, field_ty) | |
866 | } else { | |
867 | let field_ty = self.cx.tcx.normalize_erasing_regions(self.cx.param_env, field_ty); | |
868 | self.check_type_for_ffi(cache, field_ty) | |
869 | } | |
870 | } | |
871 | ||
872 | /// Checks if the given `VariantDef`'s field types are "ffi-safe". | |
873 | fn check_variant_for_ffi( | |
874 | &self, | |
875 | cache: &mut FxHashSet<Ty<'tcx>>, | |
876 | ty: Ty<'tcx>, | |
5e7ed085 | 877 | def: ty::AdtDef<'tcx>, |
f035d41b XL |
878 | variant: &ty::VariantDef, |
879 | substs: SubstsRef<'tcx>, | |
880 | ) -> FfiResult<'tcx> { | |
881 | use FfiResult::*; | |
882 | ||
5e7ed085 | 883 | if def.repr().transparent() { |
c295e0f8 | 884 | // Can assume that at most one field is not a ZST, so only check |
f035d41b | 885 | // that field's type for FFI-safety. |
1b1a35ee | 886 | if let Some(field) = transparent_newtype_field(self.cx.tcx, variant) { |
f035d41b XL |
887 | self.check_field_type_for_ffi(cache, field, substs) |
888 | } else { | |
c295e0f8 XL |
889 | // All fields are ZSTs; this means that the type should behave |
890 | // like (), which is FFI-unsafe | |
2b03887a | 891 | FfiUnsafe { ty, reason: fluent::lint_improper_ctypes_struct_zst, help: None } |
f035d41b XL |
892 | } |
893 | } else { | |
894 | // We can't completely trust repr(C) markings; make sure the fields are | |
895 | // actually safe. | |
896 | let mut all_phantom = !variant.fields.is_empty(); | |
897 | for field in &variant.fields { | |
898 | match self.check_field_type_for_ffi(cache, &field, substs) { | |
899 | FfiSafe => { | |
900 | all_phantom = false; | |
901 | } | |
902 | FfiPhantom(..) if def.is_enum() => { | |
903 | return FfiUnsafe { | |
904 | ty, | |
2b03887a | 905 | reason: fluent::lint_improper_ctypes_enum_phantomdata, |
f035d41b XL |
906 | help: None, |
907 | }; | |
908 | } | |
909 | FfiPhantom(..) => {} | |
910 | r => return r, | |
911 | } | |
912 | } | |
913 | ||
914 | if all_phantom { FfiPhantom(ty) } else { FfiSafe } | |
915 | } | |
916 | } | |
917 | ||
9fa01778 | 918 | /// Checks if the given type is "ffi-safe" (has a stable, well-defined |
b039eaaf | 919 | /// representation which can be exported to C code). |
dfeec247 | 920 | fn check_type_for_ffi(&self, cache: &mut FxHashSet<Ty<'tcx>>, ty: Ty<'tcx>) -> FfiResult<'tcx> { |
9fa01778 | 921 | use FfiResult::*; |
8bb4bdeb | 922 | |
3dfed10e | 923 | let tcx = self.cx.tcx; |
b039eaaf SL |
924 | |
925 | // Protect against infinite recursion, for example | |
926 | // `struct S(*mut S);`. | |
927 | // FIXME: A recursion limit is necessary as well, for irregular | |
b7449926 | 928 | // recursive types. |
b039eaaf SL |
929 | if !cache.insert(ty) { |
930 | return FfiSafe; | |
931 | } | |
932 | ||
fc512014 | 933 | match *ty.kind() { |
b7449926 | 934 | ty::Adt(def, substs) => { |
17df50a5 | 935 | if def.is_box() && matches!(self.mode, CItemKind::Definition) { |
2b03887a | 936 | if ty.boxed_ty().is_sized(tcx, self.cx.param_env) { |
17df50a5 XL |
937 | return FfiSafe; |
938 | } else { | |
939 | return FfiUnsafe { | |
940 | ty, | |
2b03887a | 941 | reason: fluent::lint_improper_ctypes_box, |
17df50a5 XL |
942 | help: None, |
943 | }; | |
944 | } | |
945 | } | |
8bb4bdeb | 946 | if def.is_phantom_data() { |
0531ce1d | 947 | return FfiPhantom(ty); |
8bb4bdeb | 948 | } |
c30ab7b3 | 949 | match def.adt_kind() { |
f035d41b | 950 | AdtKind::Struct | AdtKind::Union => { |
5e7ed085 | 951 | if !def.repr().c() && !def.repr().transparent() { |
0531ce1d | 952 | return FfiUnsafe { |
e1599b0c | 953 | ty, |
064997fb | 954 | reason: if def.is_struct() { |
2b03887a | 955 | fluent::lint_improper_ctypes_struct_layout_reason |
064997fb | 956 | } else { |
2b03887a | 957 | fluent::lint_improper_ctypes_union_layout_reason |
064997fb FG |
958 | }, |
959 | help: if def.is_struct() { | |
2b03887a | 960 | Some(fluent::lint_improper_ctypes_struct_layout_help) |
064997fb | 961 | } else { |
2b03887a | 962 | Some(fluent::lint_improper_ctypes_union_layout_help) |
064997fb | 963 | }, |
0531ce1d | 964 | }; |
c30ab7b3 | 965 | } |
b039eaaf | 966 | |
e74abb32 XL |
967 | let is_non_exhaustive = |
968 | def.non_enum_variant().is_field_list_non_exhaustive(); | |
5e7ed085 | 969 | if is_non_exhaustive && !def.did().is_local() { |
e74abb32 XL |
970 | return FfiUnsafe { |
971 | ty, | |
064997fb | 972 | reason: if def.is_struct() { |
2b03887a | 973 | fluent::lint_improper_ctypes_struct_non_exhaustive |
064997fb | 974 | } else { |
2b03887a | 975 | fluent::lint_improper_ctypes_union_non_exhaustive |
064997fb | 976 | }, |
e74abb32 XL |
977 | help: None, |
978 | }; | |
979 | } | |
980 | ||
2c00a5a8 | 981 | if def.non_enum_variant().fields.is_empty() { |
0531ce1d | 982 | return FfiUnsafe { |
e1599b0c | 983 | ty, |
064997fb | 984 | reason: if def.is_struct() { |
2b03887a | 985 | fluent::lint_improper_ctypes_struct_fieldless_reason |
064997fb | 986 | } else { |
2b03887a | 987 | fluent::lint_improper_ctypes_union_fieldless_reason |
064997fb FG |
988 | }, |
989 | help: if def.is_struct() { | |
2b03887a | 990 | Some(fluent::lint_improper_ctypes_struct_fieldless_help) |
064997fb | 991 | } else { |
2b03887a | 992 | Some(fluent::lint_improper_ctypes_union_fieldless_help) |
064997fb | 993 | }, |
0531ce1d | 994 | }; |
8bb4bdeb XL |
995 | } |
996 | ||
f035d41b | 997 | self.check_variant_for_ffi(cache, ty, def, def.non_enum_variant(), substs) |
b039eaaf | 998 | } |
c30ab7b3 | 999 | AdtKind::Enum => { |
5e7ed085 | 1000 | if def.variants().is_empty() { |
c30ab7b3 SL |
1001 | // Empty enums are okay... although sort of useless. |
1002 | return FfiSafe; | |
1003 | } | |
9e0c209e | 1004 | |
c30ab7b3 SL |
1005 | // Check for a repr() attribute to specify the size of the |
1006 | // discriminant. | |
5e7ed085 FG |
1007 | if !def.repr().c() && !def.repr().transparent() && def.repr().int.is_none() |
1008 | { | |
8bb4bdeb | 1009 | // Special-case types like `Option<extern fn()>`. |
3dfed10e | 1010 | if repr_nullable_ptr(self.cx, ty, self.mode).is_none() { |
0531ce1d | 1011 | return FfiUnsafe { |
e1599b0c | 1012 | ty, |
2b03887a FG |
1013 | reason: fluent::lint_improper_ctypes_enum_repr_reason, |
1014 | help: Some(fluent::lint_improper_ctypes_enum_repr_help), | |
0531ce1d | 1015 | }; |
9e0c209e | 1016 | } |
8bb4bdeb | 1017 | } |
c30ab7b3 | 1018 | |
5e7ed085 | 1019 | if def.is_variant_list_non_exhaustive() && !def.did().is_local() { |
e74abb32 XL |
1020 | return FfiUnsafe { |
1021 | ty, | |
2b03887a | 1022 | reason: fluent::lint_improper_ctypes_non_exhaustive, |
e74abb32 XL |
1023 | help: None, |
1024 | }; | |
1025 | } | |
1026 | ||
c30ab7b3 | 1027 | // Check the contained variants. |
5e7ed085 | 1028 | for variant in def.variants() { |
e74abb32 XL |
1029 | let is_non_exhaustive = variant.is_field_list_non_exhaustive(); |
1030 | if is_non_exhaustive && !variant.def_id.is_local() { | |
1031 | return FfiUnsafe { | |
1032 | ty, | |
2b03887a | 1033 | reason: fluent::lint_improper_ctypes_non_exhaustive_variant, |
e74abb32 XL |
1034 | help: None, |
1035 | }; | |
1036 | } | |
1037 | ||
f035d41b XL |
1038 | match self.check_variant_for_ffi(cache, ty, def, variant, substs) { |
1039 | FfiSafe => (), | |
1040 | r => return r, | |
9e0c209e | 1041 | } |
b039eaaf | 1042 | } |
f035d41b | 1043 | |
c30ab7b3 | 1044 | FfiSafe |
b039eaaf SL |
1045 | } |
1046 | } | |
c30ab7b3 | 1047 | } |
b039eaaf | 1048 | |
b7449926 | 1049 | ty::Char => FfiUnsafe { |
e1599b0c | 1050 | ty, |
2b03887a FG |
1051 | reason: fluent::lint_improper_ctypes_char_reason, |
1052 | help: Some(fluent::lint_improper_ctypes_char_help), | |
0531ce1d | 1053 | }, |
b039eaaf | 1054 | |
064997fb | 1055 | ty::Int(ty::IntTy::I128) | ty::Uint(ty::UintTy::U128) => { |
2b03887a | 1056 | FfiUnsafe { ty, reason: fluent::lint_improper_ctypes_128bit, help: None } |
064997fb | 1057 | } |
ea8adc8c | 1058 | |
b039eaaf | 1059 | // Primitive types with a stable representation. |
b7449926 | 1060 | ty::Bool | ty::Int(..) | ty::Uint(..) | ty::Float(..) | ty::Never => FfiSafe, |
b039eaaf | 1061 | |
b7449926 | 1062 | ty::Slice(_) => FfiUnsafe { |
e1599b0c | 1063 | ty, |
2b03887a FG |
1064 | reason: fluent::lint_improper_ctypes_slice_reason, |
1065 | help: Some(fluent::lint_improper_ctypes_slice_help), | |
0531ce1d XL |
1066 | }, |
1067 | ||
dfeec247 | 1068 | ty::Dynamic(..) => { |
2b03887a | 1069 | FfiUnsafe { ty, reason: fluent::lint_improper_ctypes_dyn, help: None } |
dfeec247 | 1070 | } |
0531ce1d | 1071 | |
b7449926 | 1072 | ty::Str => FfiUnsafe { |
e1599b0c | 1073 | ty, |
2b03887a FG |
1074 | reason: fluent::lint_improper_ctypes_str_reason, |
1075 | help: Some(fluent::lint_improper_ctypes_str_help), | |
0531ce1d XL |
1076 | }, |
1077 | ||
b7449926 | 1078 | ty::Tuple(..) => FfiUnsafe { |
e1599b0c | 1079 | ty, |
2b03887a FG |
1080 | reason: fluent::lint_improper_ctypes_tuple_reason, |
1081 | help: Some(fluent::lint_improper_ctypes_tuple_help), | |
0531ce1d | 1082 | }, |
b039eaaf | 1083 | |
f035d41b XL |
1084 | ty::RawPtr(ty::TypeAndMut { ty, .. }) | ty::Ref(_, ty, _) |
1085 | if { | |
3dfed10e | 1086 | matches!(self.mode, CItemKind::Definition) |
2b03887a | 1087 | && ty.is_sized(self.cx.tcx, self.cx.param_env) |
f035d41b XL |
1088 | } => |
1089 | { | |
1090 | FfiSafe | |
1091 | } | |
1092 | ||
c295e0f8 XL |
1093 | ty::RawPtr(ty::TypeAndMut { ty, .. }) |
1094 | if match ty.kind() { | |
1095 | ty::Tuple(tuple) => tuple.is_empty(), | |
1096 | _ => false, | |
1097 | } => | |
1098 | { | |
1099 | FfiSafe | |
1100 | } | |
1101 | ||
dfeec247 XL |
1102 | ty::RawPtr(ty::TypeAndMut { ty, .. }) | ty::Ref(_, ty, _) => { |
1103 | self.check_type_for_ffi(cache, ty) | |
1104 | } | |
b039eaaf | 1105 | |
60c5eb7d | 1106 | ty::Array(inner_ty, _) => self.check_type_for_ffi(cache, inner_ty), |
b039eaaf | 1107 | |
b7449926 | 1108 | ty::FnPtr(sig) => { |
f035d41b XL |
1109 | if self.is_internal_abi(sig.abi()) { |
1110 | return FfiUnsafe { | |
1111 | ty, | |
2b03887a FG |
1112 | reason: fluent::lint_improper_ctypes_fnptr_reason, |
1113 | help: Some(fluent::lint_improper_ctypes_fnptr_help), | |
f035d41b | 1114 | }; |
b039eaaf SL |
1115 | } |
1116 | ||
fc512014 | 1117 | let sig = tcx.erase_late_bound_regions(sig); |
b7449926 | 1118 | if !sig.output().is_unit() { |
476ff2be | 1119 | let r = self.check_type_for_ffi(cache, sig.output()); |
5bcae85e SL |
1120 | match r { |
1121 | FfiSafe => {} | |
c30ab7b3 SL |
1122 | _ => { |
1123 | return r; | |
1124 | } | |
b039eaaf SL |
1125 | } |
1126 | } | |
476ff2be | 1127 | for arg in sig.inputs() { |
5099ac24 | 1128 | let r = self.check_type_for_ffi(cache, *arg); |
b039eaaf SL |
1129 | match r { |
1130 | FfiSafe => {} | |
c30ab7b3 SL |
1131 | _ => { |
1132 | return r; | |
1133 | } | |
b039eaaf SL |
1134 | } |
1135 | } | |
1136 | FfiSafe | |
1137 | } | |
1138 | ||
b7449926 XL |
1139 | ty::Foreign(..) => FfiSafe, |
1140 | ||
f035d41b XL |
1141 | // While opaque types are checked for earlier, if a projection in a struct field |
1142 | // normalizes to an opaque type, then it will reach this branch. | |
1143 | ty::Opaque(..) => { | |
2b03887a | 1144 | FfiUnsafe { ty, reason: fluent::lint_improper_ctypes_opaque, help: None } |
f035d41b XL |
1145 | } |
1146 | ||
1147 | // `extern "C" fn` functions can have type parameters, which may or may not be FFI-safe, | |
1148 | // so they are currently ignored for the purposes of this lint. | |
3dfed10e | 1149 | ty::Param(..) | ty::Projection(..) if matches!(self.mode, CItemKind::Definition) => { |
f035d41b XL |
1150 | FfiSafe |
1151 | } | |
1152 | ||
dfeec247 | 1153 | ty::Param(..) |
f035d41b | 1154 | | ty::Projection(..) |
dfeec247 XL |
1155 | | ty::Infer(..) |
1156 | | ty::Bound(..) | |
f035d41b | 1157 | | ty::Error(_) |
dfeec247 XL |
1158 | | ty::Closure(..) |
1159 | | ty::Generator(..) | |
1160 | | ty::GeneratorWitness(..) | |
1161 | | ty::Placeholder(..) | |
dfeec247 | 1162 | | ty::FnDef(..) => bug!("unexpected type in foreign function: {:?}", ty), |
e1599b0c XL |
1163 | } |
1164 | } | |
1165 | ||
1166 | fn emit_ffi_unsafe_type_lint( | |
1167 | &mut self, | |
1168 | ty: Ty<'tcx>, | |
1169 | sp: Span, | |
064997fb FG |
1170 | note: DiagnosticMessage, |
1171 | help: Option<DiagnosticMessage>, | |
e1599b0c | 1172 | ) { |
f035d41b | 1173 | let lint = match self.mode { |
3dfed10e XL |
1174 | CItemKind::Declaration => IMPROPER_CTYPES, |
1175 | CItemKind::Definition => IMPROPER_CTYPES_DEFINITIONS, | |
f035d41b XL |
1176 | }; |
1177 | ||
2b03887a | 1178 | self.cx.struct_span_lint(lint, sp, fluent::lint_improper_ctypes, |lint| { |
f035d41b | 1179 | let item_description = match self.mode { |
3dfed10e XL |
1180 | CItemKind::Declaration => "block", |
1181 | CItemKind::Definition => "fn", | |
f035d41b | 1182 | }; |
2b03887a FG |
1183 | lint.set_arg("ty", ty); |
1184 | lint.set_arg("desc", item_description); | |
1185 | lint.span_label(sp, fluent::label); | |
74b04a01 | 1186 | if let Some(help) = help { |
2b03887a | 1187 | lint.help(help); |
e1599b0c | 1188 | } |
2b03887a | 1189 | lint.note(note); |
1b1a35ee | 1190 | if let ty::Adt(def, _) = ty.kind() { |
5e7ed085 | 1191 | if let Some(sp) = self.cx.tcx.hir().span_if_local(def.did()) { |
2b03887a | 1192 | lint.span_note(sp, fluent::note); |
74b04a01 XL |
1193 | } |
1194 | } | |
2b03887a | 1195 | lint |
74b04a01 | 1196 | }); |
e1599b0c XL |
1197 | } |
1198 | ||
1199 | fn check_for_opaque_ty(&mut self, sp: Span, ty: Ty<'tcx>) -> bool { | |
487cf647 FG |
1200 | struct ProhibitOpaqueTypes; |
1201 | impl<'tcx> ty::visit::TypeVisitor<'tcx> for ProhibitOpaqueTypes { | |
fc512014 XL |
1202 | type BreakTy = Ty<'tcx>; |
1203 | ||
1204 | fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> { | |
487cf647 FG |
1205 | if !ty.has_opaque_types() { |
1206 | return ControlFlow::CONTINUE; | |
1207 | } | |
1208 | ||
1209 | if let ty::Opaque(..) = ty.kind() { | |
1210 | ControlFlow::Break(ty) | |
1211 | } else { | |
1212 | ty.super_visit_with(self) | |
e1599b0c XL |
1213 | } |
1214 | } | |
1215 | } | |
1216 | ||
487cf647 FG |
1217 | if let Some(ty) = self |
1218 | .cx | |
1219 | .tcx | |
1220 | .normalize_erasing_regions(self.cx.param_env, ty) | |
1221 | .visit_with(&mut ProhibitOpaqueTypes) | |
1222 | .break_value() | |
1223 | { | |
2b03887a | 1224 | self.emit_ffi_unsafe_type_lint(ty, sp, fluent::lint_improper_ctypes_opaque, None); |
e1599b0c XL |
1225 | true |
1226 | } else { | |
1227 | false | |
b039eaaf SL |
1228 | } |
1229 | } | |
1230 | ||
f035d41b XL |
1231 | fn check_type_for_ffi_and_report_errors( |
1232 | &mut self, | |
1233 | sp: Span, | |
1234 | ty: Ty<'tcx>, | |
1235 | is_static: bool, | |
1236 | is_return_type: bool, | |
1237 | ) { | |
e1599b0c XL |
1238 | // We have to check for opaque types before `normalize_erasing_regions`, |
1239 | // which will replace opaque types with their underlying concrete type. | |
1240 | if self.check_for_opaque_ty(sp, ty) { | |
1241 | // We've already emitted an error due to an opaque type. | |
1242 | return; | |
1243 | } | |
1244 | ||
54a0048b SL |
1245 | // it is only OK to use this function because extern fns cannot have |
1246 | // any generic types right now: | |
f035d41b XL |
1247 | let ty = self.cx.tcx.normalize_erasing_regions(self.cx.param_env, ty); |
1248 | ||
1249 | // C doesn't really support passing arrays by value - the only way to pass an array by value | |
1250 | // is through a struct. So, first test that the top level isn't an array, and then | |
1251 | // recursively check the types inside. | |
60c5eb7d XL |
1252 | if !is_static && self.check_for_array_ty(sp, ty) { |
1253 | return; | |
1254 | } | |
b039eaaf | 1255 | |
f035d41b XL |
1256 | // Don't report FFI errors for unit return types. This check exists here, and not in |
1257 | // `check_foreign_fn` (where it would make more sense) so that normalization has definitely | |
1258 | // happened. | |
1259 | if is_return_type && ty.is_unit() { | |
1260 | return; | |
1261 | } | |
1262 | ||
0bf4aa26 | 1263 | match self.check_type_for_ffi(&mut FxHashSet::default(), ty) { |
b039eaaf | 1264 | FfiResult::FfiSafe => {} |
0531ce1d | 1265 | FfiResult::FfiPhantom(ty) => { |
064997fb FG |
1266 | self.emit_ffi_unsafe_type_lint( |
1267 | ty, | |
1268 | sp, | |
2b03887a | 1269 | fluent::lint_improper_ctypes_only_phantomdata, |
064997fb FG |
1270 | None, |
1271 | ); | |
9e0c209e | 1272 | } |
f035d41b XL |
1273 | // If `ty` is a `repr(transparent)` newtype, and the non-zero-sized type is a generic |
1274 | // argument, which after substitution, is `()`, then this branch can be hit. | |
3dfed10e | 1275 | FfiResult::FfiUnsafe { ty, .. } if is_return_type && ty.is_unit() => {} |
e1599b0c | 1276 | FfiResult::FfiUnsafe { ty, reason, help } => { |
064997fb | 1277 | self.emit_ffi_unsafe_type_lint(ty, sp, reason, help); |
b039eaaf SL |
1278 | } |
1279 | } | |
1280 | } | |
b039eaaf | 1281 | |
dfeec247 | 1282 | fn check_foreign_fn(&mut self, id: hir::HirId, decl: &hir::FnDecl<'_>) { |
416331ca | 1283 | let def_id = self.cx.tcx.hir().local_def_id(id); |
041b39d2 | 1284 | let sig = self.cx.tcx.fn_sig(def_id); |
fc512014 | 1285 | let sig = self.cx.tcx.erase_late_bound_regions(sig); |
54a0048b | 1286 | |
cdc7bbd5 | 1287 | for (input_ty, input_hir) in iter::zip(sig.inputs(), decl.inputs) { |
5099ac24 | 1288 | self.check_type_for_ffi_and_report_errors(input_hir.span, *input_ty, false, false); |
54a0048b SL |
1289 | } |
1290 | ||
74b04a01 | 1291 | if let hir::FnRetTy::Return(ref ret_hir) = decl.output { |
476ff2be | 1292 | let ret_ty = sig.output(); |
f035d41b | 1293 | self.check_type_for_ffi_and_report_errors(ret_hir.span, ret_ty, false, true); |
b039eaaf SL |
1294 | } |
1295 | } | |
54a0048b | 1296 | |
532ac7d7 | 1297 | fn check_foreign_static(&mut self, id: hir::HirId, span: Span) { |
416331ca | 1298 | let def_id = self.cx.tcx.hir().local_def_id(id); |
7cac9316 | 1299 | let ty = self.cx.tcx.type_of(def_id); |
f035d41b | 1300 | self.check_type_for_ffi_and_report_errors(span, ty, true, false); |
54a0048b | 1301 | } |
b039eaaf | 1302 | |
3dfed10e | 1303 | fn is_internal_abi(&self, abi: SpecAbi) -> bool { |
29967ef6 XL |
1304 | matches!( |
1305 | abi, | |
1306 | SpecAbi::Rust | SpecAbi::RustCall | SpecAbi::RustIntrinsic | SpecAbi::PlatformIntrinsic | |
1307 | ) | |
f035d41b XL |
1308 | } |
1309 | } | |
1310 | ||
1311 | impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDeclarations { | |
1312 | fn check_foreign_item(&mut self, cx: &LateContext<'_>, it: &hir::ForeignItem<'_>) { | |
3dfed10e | 1313 | let mut vis = ImproperCTypesVisitor { cx, mode: CItemKind::Declaration }; |
6a06907d | 1314 | let abi = cx.tcx.hir().get_foreign_abi(it.hir_id()); |
f035d41b XL |
1315 | |
1316 | if !vis.is_internal_abi(abi) { | |
e74abb32 | 1317 | match it.kind { |
b7449926 | 1318 | hir::ForeignItemKind::Fn(ref decl, _, _) => { |
6a06907d | 1319 | vis.check_foreign_fn(it.hir_id(), decl); |
b7449926 XL |
1320 | } |
1321 | hir::ForeignItemKind::Static(ref ty, _) => { | |
6a06907d | 1322 | vis.check_foreign_static(it.hir_id(), ty.span); |
b039eaaf | 1323 | } |
dfeec247 | 1324 | hir::ForeignItemKind::Type => (), |
b039eaaf | 1325 | } |
b039eaaf SL |
1326 | } |
1327 | } | |
1328 | } | |
5bcae85e | 1329 | |
f035d41b XL |
1330 | impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDefinitions { |
1331 | fn check_fn( | |
1332 | &mut self, | |
1333 | cx: &LateContext<'tcx>, | |
1334 | kind: hir::intravisit::FnKind<'tcx>, | |
1335 | decl: &'tcx hir::FnDecl<'_>, | |
1336 | _: &'tcx hir::Body<'_>, | |
1337 | _: Span, | |
1338 | hir_id: hir::HirId, | |
1339 | ) { | |
1340 | use hir::intravisit::FnKind; | |
1341 | ||
1342 | let abi = match kind { | |
1343 | FnKind::ItemFn(_, _, header, ..) => header.abi, | |
1344 | FnKind::Method(_, sig, ..) => sig.header.abi, | |
1345 | _ => return, | |
1346 | }; | |
1347 | ||
3dfed10e | 1348 | let mut vis = ImproperCTypesVisitor { cx, mode: CItemKind::Definition }; |
f035d41b XL |
1349 | if !vis.is_internal_abi(abi) { |
1350 | vis.check_foreign_fn(hir_id, decl); | |
1351 | } | |
1352 | } | |
1353 | } | |
1354 | ||
532ac7d7 | 1355 | declare_lint_pass!(VariantSizeDifferences => [VARIANT_SIZE_DIFFERENCES]); |
5bcae85e | 1356 | |
f035d41b XL |
1357 | impl<'tcx> LateLintPass<'tcx> for VariantSizeDifferences { |
1358 | fn check_item(&mut self, cx: &LateContext<'_>, it: &hir::Item<'_>) { | |
e74abb32 | 1359 | if let hir::ItemKind::Enum(ref enum_definition, _) = it.kind { |
2b03887a | 1360 | let t = cx.tcx.type_of(it.owner_id); |
fc512014 | 1361 | let ty = cx.tcx.erase_regions(t); |
5e7ed085 | 1362 | let Ok(layout) = cx.layout_of(ty) else { return }; |
a2a8927a | 1363 | let Variants::Multiple { |
c295e0f8 | 1364 | tag_encoding: TagEncoding::Direct, tag, ref variants, .. |
a2a8927a XL |
1365 | } = &layout.variants else { |
1366 | return | |
532ac7d7 XL |
1367 | }; |
1368 | ||
04454e1e | 1369 | let tag_size = tag.size(&cx.tcx).bytes(); |
532ac7d7 | 1370 | |
dfeec247 XL |
1371 | debug!( |
1372 | "enum `{}` is {} bytes large with layout:\n{:#?}", | |
1373 | t, | |
1374 | layout.size.bytes(), | |
1375 | layout | |
1376 | ); | |
532ac7d7 | 1377 | |
cdc7bbd5 | 1378 | let (largest, slargest, largest_index) = iter::zip(enum_definition.variants, variants) |
532ac7d7 | 1379 | .map(|(variant, variant_layout)| { |
f035d41b | 1380 | // Subtract the size of the enum tag. |
487cf647 | 1381 | let bytes = variant_layout.size.bytes().saturating_sub(tag_size); |
532ac7d7 | 1382 | |
dfeec247 | 1383 | debug!("- variant `{}` is {} bytes large", variant.ident, bytes); |
532ac7d7 XL |
1384 | bytes |
1385 | }) | |
1386 | .enumerate() | |
dfeec247 XL |
1387 | .fold((0, 0, 0), |(l, s, li), (idx, size)| { |
1388 | if size > l { | |
1389 | (size, l, idx) | |
1390 | } else if size > s { | |
1391 | (l, size, li) | |
1392 | } else { | |
1393 | (l, s, li) | |
1394 | } | |
532ac7d7 XL |
1395 | }); |
1396 | ||
1397 | // We only warn if the largest variant is at least thrice as large as | |
1398 | // the second-largest. | |
1399 | if largest > slargest * 3 && slargest > 0 { | |
74b04a01 | 1400 | cx.struct_span_lint( |
dfeec247 XL |
1401 | VARIANT_SIZE_DIFFERENCES, |
1402 | enum_definition.variants[largest_index].span, | |
2b03887a FG |
1403 | fluent::lint_variant_size_differences, |
1404 | |lint| lint.set_arg("largest", largest), | |
dfeec247 | 1405 | ); |
5bcae85e SL |
1406 | } |
1407 | } | |
1408 | } | |
1409 | } | |
94222f64 XL |
1410 | |
1411 | declare_lint! { | |
1412 | /// The `invalid_atomic_ordering` lint detects passing an `Ordering` | |
1413 | /// to an atomic operation that does not support that ordering. | |
1414 | /// | |
1415 | /// ### Example | |
1416 | /// | |
1417 | /// ```rust,compile_fail | |
1418 | /// # use core::sync::atomic::{AtomicU8, Ordering}; | |
1419 | /// let atom = AtomicU8::new(0); | |
1420 | /// let value = atom.load(Ordering::Release); | |
1421 | /// # let _ = value; | |
1422 | /// ``` | |
1423 | /// | |
1424 | /// {{produces}} | |
1425 | /// | |
1426 | /// ### Explanation | |
1427 | /// | |
1428 | /// Some atomic operations are only supported for a subset of the | |
1429 | /// `atomic::Ordering` variants. Passing an unsupported variant will cause | |
1430 | /// an unconditional panic at runtime, which is detected by this lint. | |
1431 | /// | |
1432 | /// This lint will trigger in the following cases: (where `AtomicType` is an | |
1433 | /// atomic type from `core::sync::atomic`, such as `AtomicBool`, | |
1434 | /// `AtomicPtr`, `AtomicUsize`, or any of the other integer atomics). | |
1435 | /// | |
1436 | /// - Passing `Ordering::Acquire` or `Ordering::AcqRel` to | |
1437 | /// `AtomicType::store`. | |
1438 | /// | |
1439 | /// - Passing `Ordering::Release` or `Ordering::AcqRel` to | |
1440 | /// `AtomicType::load`. | |
1441 | /// | |
1442 | /// - Passing `Ordering::Relaxed` to `core::sync::atomic::fence` or | |
1443 | /// `core::sync::atomic::compiler_fence`. | |
1444 | /// | |
1445 | /// - Passing `Ordering::Release` or `Ordering::AcqRel` as the failure | |
1446 | /// ordering for any of `AtomicType::compare_exchange`, | |
1447 | /// `AtomicType::compare_exchange_weak`, or `AtomicType::fetch_update`. | |
94222f64 XL |
1448 | INVALID_ATOMIC_ORDERING, |
1449 | Deny, | |
1450 | "usage of invalid atomic ordering in atomic operations and memory fences" | |
1451 | } | |
1452 | ||
1453 | declare_lint_pass!(InvalidAtomicOrdering => [INVALID_ATOMIC_ORDERING]); | |
1454 | ||
1455 | impl InvalidAtomicOrdering { | |
1456 | fn inherent_atomic_method_call<'hir>( | |
1457 | cx: &LateContext<'_>, | |
1458 | expr: &Expr<'hir>, | |
1459 | recognized_names: &[Symbol], // used for fast path calculation | |
1460 | ) -> Option<(Symbol, &'hir [Expr<'hir>])> { | |
1461 | const ATOMIC_TYPES: &[Symbol] = &[ | |
1462 | sym::AtomicBool, | |
1463 | sym::AtomicPtr, | |
1464 | sym::AtomicUsize, | |
1465 | sym::AtomicU8, | |
1466 | sym::AtomicU16, | |
1467 | sym::AtomicU32, | |
1468 | sym::AtomicU64, | |
1469 | sym::AtomicU128, | |
1470 | sym::AtomicIsize, | |
1471 | sym::AtomicI8, | |
1472 | sym::AtomicI16, | |
1473 | sym::AtomicI32, | |
1474 | sym::AtomicI64, | |
1475 | sym::AtomicI128, | |
1476 | ]; | |
f2b60f7d | 1477 | if let ExprKind::MethodCall(ref method_path, _, args, _) = &expr.kind |
5e7ed085 FG |
1478 | && recognized_names.contains(&method_path.ident.name) |
1479 | && let Some(m_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) | |
1480 | && let Some(impl_did) = cx.tcx.impl_of_method(m_def_id) | |
1481 | && let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() | |
94222f64 | 1482 | // skip extension traits, only lint functions from the standard library |
5e7ed085 | 1483 | && cx.tcx.trait_id_of_impl(impl_did).is_none() |
04454e1e | 1484 | && let parent = cx.tcx.parent(adt.did()) |
5e7ed085 FG |
1485 | && cx.tcx.is_diagnostic_item(sym::atomic_mod, parent) |
1486 | && ATOMIC_TYPES.contains(&cx.tcx.item_name(adt.did())) | |
1487 | { | |
1488 | return Some((method_path.ident.name, args)); | |
94222f64 XL |
1489 | } |
1490 | None | |
1491 | } | |
1492 | ||
064997fb FG |
1493 | fn match_ordering(cx: &LateContext<'_>, ord_arg: &Expr<'_>) -> Option<Symbol> { |
1494 | let ExprKind::Path(ref ord_qpath) = ord_arg.kind else { return None }; | |
1495 | let did = cx.qpath_res(ord_qpath, ord_arg.hir_id).opt_def_id()?; | |
94222f64 XL |
1496 | let tcx = cx.tcx; |
1497 | let atomic_ordering = tcx.get_diagnostic_item(sym::Ordering); | |
064997fb FG |
1498 | let name = tcx.item_name(did); |
1499 | let parent = tcx.parent(did); | |
1500 | [sym::Relaxed, sym::Release, sym::Acquire, sym::AcqRel, sym::SeqCst].into_iter().find( | |
1501 | |&ordering| { | |
1502 | name == ordering | |
1503 | && (Some(parent) == atomic_ordering | |
1504 | // needed in case this is a ctor, not a variant | |
1505 | || tcx.opt_parent(parent) == atomic_ordering) | |
1506 | }, | |
1507 | ) | |
94222f64 XL |
1508 | } |
1509 | ||
1510 | fn check_atomic_load_store(cx: &LateContext<'_>, expr: &Expr<'_>) { | |
5e7ed085 | 1511 | if let Some((method, args)) = Self::inherent_atomic_method_call(cx, expr, &[sym::load, sym::store]) |
2b03887a FG |
1512 | && let Some((ordering_arg, invalid_ordering, msg)) = match method { |
1513 | sym::load => Some((&args[0], sym::Release, fluent::lint_atomic_ordering_load)), | |
1514 | sym::store => Some((&args[1], sym::Acquire, fluent::lint_atomic_ordering_store)), | |
94222f64 | 1515 | _ => None, |
94222f64 | 1516 | } |
064997fb FG |
1517 | && let Some(ordering) = Self::match_ordering(cx, ordering_arg) |
1518 | && (ordering == invalid_ordering || ordering == sym::AcqRel) | |
5e7ed085 | 1519 | { |
2b03887a FG |
1520 | cx.struct_span_lint(INVALID_ATOMIC_ORDERING, ordering_arg.span, msg, |lint| { |
1521 | lint.help(fluent::help) | |
5e7ed085 | 1522 | }); |
94222f64 XL |
1523 | } |
1524 | } | |
1525 | ||
1526 | fn check_memory_fence(cx: &LateContext<'_>, expr: &Expr<'_>) { | |
5e7ed085 FG |
1527 | if let ExprKind::Call(ref func, ref args) = expr.kind |
1528 | && let ExprKind::Path(ref func_qpath) = func.kind | |
1529 | && let Some(def_id) = cx.qpath_res(func_qpath, func.hir_id).opt_def_id() | |
1530 | && matches!(cx.tcx.get_diagnostic_name(def_id), Some(sym::fence | sym::compiler_fence)) | |
064997fb | 1531 | && Self::match_ordering(cx, &args[0]) == Some(sym::Relaxed) |
5e7ed085 | 1532 | { |
2b03887a FG |
1533 | cx.struct_span_lint(INVALID_ATOMIC_ORDERING, args[0].span, fluent::lint_atomic_ordering_fence, |lint| { |
1534 | lint | |
1535 | .help(fluent::help) | |
5e7ed085 | 1536 | }); |
94222f64 XL |
1537 | } |
1538 | } | |
1539 | ||
1540 | fn check_atomic_compare_exchange(cx: &LateContext<'_>, expr: &Expr<'_>) { | |
064997fb FG |
1541 | let Some((method, args)) = Self::inherent_atomic_method_call(cx, expr, &[sym::fetch_update, sym::compare_exchange, sym::compare_exchange_weak]) |
1542 | else {return }; | |
1543 | ||
1544 | let fail_order_arg = match method { | |
f2b60f7d FG |
1545 | sym::fetch_update => &args[1], |
1546 | sym::compare_exchange | sym::compare_exchange_weak => &args[3], | |
064997fb FG |
1547 | _ => return, |
1548 | }; | |
1549 | ||
1550 | let Some(fail_ordering) = Self::match_ordering(cx, fail_order_arg) else { return }; | |
1551 | ||
1552 | if matches!(fail_ordering, sym::Release | sym::AcqRel) { | |
1553 | #[derive(LintDiagnostic)] | |
2b03887a | 1554 | #[diag(lint_atomic_ordering_invalid)] |
064997fb FG |
1555 | #[help] |
1556 | struct InvalidAtomicOrderingDiag { | |
1557 | method: Symbol, | |
1558 | #[label] | |
1559 | fail_order_arg_span: Span, | |
94222f64 | 1560 | } |
064997fb FG |
1561 | |
1562 | cx.emit_spanned_lint( | |
1563 | INVALID_ATOMIC_ORDERING, | |
1564 | fail_order_arg.span, | |
1565 | InvalidAtomicOrderingDiag { method, fail_order_arg_span: fail_order_arg.span }, | |
1566 | ); | |
94222f64 XL |
1567 | } |
1568 | } | |
1569 | } | |
1570 | ||
1571 | impl<'tcx> LateLintPass<'tcx> for InvalidAtomicOrdering { | |
1572 | fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { | |
1573 | Self::check_atomic_load_store(cx, expr); | |
1574 | Self::check_memory_fence(cx, expr); | |
1575 | Self::check_atomic_compare_exchange(cx, expr); | |
1576 | } | |
1577 | } |