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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; | |
94222f64 | 14 | use rustc_span::{Span, Symbol, DUMMY_SP}; |
04454e1e | 15 | use rustc_target::abi::{Abi, 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 | ||
48663c56 XL |
119 | /// Attempts to special-case the overflowing literal lint when it occurs as a range endpoint. |
120 | /// Returns `true` iff the lint was overridden. | |
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 | ||
74b04a01 | 143 | let mut overwritten = false; |
f2b60f7d FG |
144 | // We can suggest using an inclusive range |
145 | // (`..=`) instead only if it is the `end` that is | |
146 | // overflowing and only by 1. | |
147 | if eps[1].expr.hir_id == expr.hir_id && lit_val - 1 == max { | |
148 | cx.struct_span_lint(OVERFLOWING_LITERALS, struct_expr.span, |lint| { | |
149 | let mut err = lint.build(fluent::lint::range_endpoint_out_of_range); | |
150 | err.set_arg("ty", ty); | |
151 | if let Ok(start) = cx.sess().source_map().span_to_snippet(eps[0].span) { | |
152 | use ast::{LitIntType, LitKind}; | |
153 | // We need to preserve the literal's suffix, | |
154 | // as it may determine typing information. | |
155 | let suffix = match lit.node { | |
156 | LitKind::Int(_, LitIntType::Signed(s)) => s.name_str(), | |
157 | LitKind::Int(_, LitIntType::Unsigned(s)) => s.name_str(), | |
158 | LitKind::Int(_, LitIntType::Unsuffixed) => "", | |
159 | _ => bug!(), | |
160 | }; | |
161 | let suggestion = format!("{}..={}{}", start, lit_val - 1, suffix); | |
162 | err.span_suggestion( | |
163 | struct_expr.span, | |
164 | fluent::lint::suggestion, | |
165 | suggestion, | |
166 | Applicability::MachineApplicable, | |
167 | ); | |
168 | err.emit(); | |
169 | overwritten = true; | |
170 | } | |
171 | }); | |
48663c56 | 172 | } |
74b04a01 | 173 | overwritten |
48663c56 XL |
174 | } |
175 | ||
176 | // For `isize` & `usize`, be conservative with the warnings, so that the | |
177 | // warnings are consistent between 32- and 64-bit platforms. | |
5869c6ff | 178 | fn int_ty_range(int_ty: ty::IntTy) -> (i128, i128) { |
48663c56 | 179 | match int_ty { |
5869c6ff XL |
180 | ty::IntTy::Isize => (i64::MIN.into(), i64::MAX.into()), |
181 | ty::IntTy::I8 => (i8::MIN.into(), i8::MAX.into()), | |
182 | ty::IntTy::I16 => (i16::MIN.into(), i16::MAX.into()), | |
183 | ty::IntTy::I32 => (i32::MIN.into(), i32::MAX.into()), | |
184 | ty::IntTy::I64 => (i64::MIN.into(), i64::MAX.into()), | |
185 | ty::IntTy::I128 => (i128::MIN, i128::MAX), | |
48663c56 XL |
186 | } |
187 | } | |
188 | ||
5869c6ff | 189 | fn uint_ty_range(uint_ty: ty::UintTy) -> (u128, u128) { |
29967ef6 | 190 | let max = match uint_ty { |
5869c6ff XL |
191 | ty::UintTy::Usize => u64::MAX.into(), |
192 | ty::UintTy::U8 => u8::MAX.into(), | |
193 | ty::UintTy::U16 => u16::MAX.into(), | |
194 | ty::UintTy::U32 => u32::MAX.into(), | |
195 | ty::UintTy::U64 => u64::MAX.into(), | |
196 | ty::UintTy::U128 => u128::MAX, | |
29967ef6 XL |
197 | }; |
198 | (0, max) | |
48663c56 XL |
199 | } |
200 | ||
f035d41b | 201 | fn get_bin_hex_repr(cx: &LateContext<'_>, lit: &hir::Lit) -> Option<String> { |
48663c56 XL |
202 | let src = cx.sess().source_map().span_to_snippet(lit.span).ok()?; |
203 | let firstch = src.chars().next()?; | |
204 | ||
205 | if firstch == '0' { | |
206 | match src.chars().nth(1) { | |
ba9703b0 | 207 | Some('x' | 'b') => return Some(src), |
48663c56 XL |
208 | _ => return None, |
209 | } | |
210 | } | |
211 | ||
212 | None | |
213 | } | |
214 | ||
215 | fn report_bin_hex_error( | |
f035d41b | 216 | cx: &LateContext<'_>, |
dfeec247 | 217 | expr: &hir::Expr<'_>, |
48663c56 XL |
218 | ty: attr::IntType, |
219 | repr_str: String, | |
220 | val: u128, | |
221 | negative: bool, | |
222 | ) { | |
ba9703b0 | 223 | let size = Integer::from_attr(&cx.tcx, ty).size(); |
74b04a01 XL |
224 | cx.struct_span_lint(OVERFLOWING_LITERALS, expr.span, |lint| { |
225 | let (t, actually) = match ty { | |
226 | attr::IntType::SignedInt(t) => { | |
6a06907d XL |
227 | let actually = if negative { |
228 | -(size.sign_extend(val) as i128) | |
229 | } else { | |
230 | size.sign_extend(val) as i128 | |
231 | }; | |
74b04a01 XL |
232 | (t.name_str(), actually.to_string()) |
233 | } | |
234 | attr::IntType::UnsignedInt(t) => { | |
29967ef6 | 235 | let actually = size.truncate(val); |
74b04a01 XL |
236 | (t.name_str(), actually.to_string()) |
237 | } | |
238 | }; | |
064997fb | 239 | let mut err = lint.build(fluent::lint::overflowing_bin_hex); |
6a06907d XL |
240 | if negative { |
241 | // If the value is negative, | |
242 | // emits a note about the value itself, apart from the literal. | |
064997fb FG |
243 | err.note(fluent::lint::negative_note); |
244 | err.note(fluent::lint::negative_becomes_note); | |
6a06907d | 245 | } else { |
064997fb | 246 | err.note(fluent::lint::positive_note); |
6a06907d | 247 | } |
f035d41b | 248 | if let Some(sugg_ty) = |
5099ac24 | 249 | get_type_suggestion(cx.typeck_results().node_type(expr.hir_id), val, negative) |
74b04a01 | 250 | { |
064997fb | 251 | err.set_arg("suggestion_ty", sugg_ty); |
74b04a01 XL |
252 | if let Some(pos) = repr_str.chars().position(|c| c == 'i' || c == 'u') { |
253 | let (sans_suffix, _) = repr_str.split_at(pos); | |
254 | err.span_suggestion( | |
255 | expr.span, | |
064997fb | 256 | fluent::lint::suggestion, |
74b04a01 XL |
257 | format!("{}{}", sans_suffix, sugg_ty), |
258 | Applicability::MachineApplicable, | |
259 | ); | |
260 | } else { | |
064997fb | 261 | err.help(fluent::lint::help); |
74b04a01 | 262 | } |
48663c56 | 263 | } |
064997fb FG |
264 | err.set_arg("ty", t); |
265 | err.set_arg("lit", repr_str); | |
266 | err.set_arg("dec", val); | |
267 | err.set_arg("actually", actually); | |
74b04a01 XL |
268 | err.emit(); |
269 | }); | |
48663c56 XL |
270 | } |
271 | ||
272 | // This function finds the next fitting type and generates a suggestion string. | |
273 | // It searches for fitting types in the following way (`X < Y`): | |
274 | // - `iX`: if literal fits in `uX` => `uX`, else => `iY` | |
275 | // - `-iX` => `iY` | |
276 | // - `uX` => `uY` | |
277 | // | |
278 | // No suggestion for: `isize`, `usize`. | |
60c5eb7d | 279 | fn get_type_suggestion(t: Ty<'_>, val: u128, negative: bool) -> Option<&'static str> { |
5869c6ff XL |
280 | use ty::IntTy::*; |
281 | use ty::UintTy::*; | |
48663c56 XL |
282 | macro_rules! find_fit { |
283 | ($ty:expr, $val:expr, $negative:expr, | |
284 | $($type:ident => [$($utypes:expr),*] => [$($itypes:expr),*]),+) => { | |
285 | { | |
286 | let _neg = if negative { 1 } else { 0 }; | |
287 | match $ty { | |
288 | $($type => { | |
289 | $(if !negative && val <= uint_ty_range($utypes).1 { | |
60c5eb7d | 290 | return Some($utypes.name_str()) |
48663c56 XL |
291 | })* |
292 | $(if val <= int_ty_range($itypes).1 as u128 + _neg { | |
60c5eb7d | 293 | return Some($itypes.name_str()) |
48663c56 XL |
294 | })* |
295 | None | |
dc9dc135 | 296 | },)+ |
48663c56 XL |
297 | _ => None |
298 | } | |
299 | } | |
300 | } | |
301 | } | |
1b1a35ee | 302 | match t.kind() { |
48663c56 XL |
303 | ty::Int(i) => find_fit!(i, val, negative, |
304 | I8 => [U8] => [I16, I32, I64, I128], | |
305 | I16 => [U16] => [I32, I64, I128], | |
306 | I32 => [U32] => [I64, I128], | |
307 | I64 => [U64] => [I128], | |
308 | I128 => [U128] => []), | |
309 | ty::Uint(u) => find_fit!(u, val, negative, | |
310 | U8 => [U8, U16, U32, U64, U128] => [], | |
311 | U16 => [U16, U32, U64, U128] => [], | |
312 | U32 => [U32, U64, U128] => [], | |
313 | U64 => [U64, U128] => [], | |
314 | U128 => [U128] => []), | |
315 | _ => None, | |
316 | } | |
317 | } | |
318 | ||
f035d41b XL |
319 | fn lint_int_literal<'tcx>( |
320 | cx: &LateContext<'tcx>, | |
48663c56 | 321 | type_limits: &TypeLimits, |
dfeec247 | 322 | e: &'tcx hir::Expr<'tcx>, |
48663c56 | 323 | lit: &hir::Lit, |
5869c6ff | 324 | t: ty::IntTy, |
48663c56 XL |
325 | v: u128, |
326 | ) { | |
29967ef6 | 327 | let int_type = t.normalize(cx.sess().target.pointer_width); |
ba9703b0 | 328 | let (min, max) = int_ty_range(int_type); |
48663c56 | 329 | let max = max as u128; |
ba9703b0 | 330 | let negative = type_limits.negated_expr_id == Some(e.hir_id); |
48663c56 XL |
331 | |
332 | // Detect literal value out of range [min, max] inclusive | |
333 | // avoiding use of -min to prevent overflow/panic | |
334 | if (negative && v > max + 1) || (!negative && v > max) { | |
335 | if let Some(repr_str) = get_bin_hex_repr(cx, lit) { | |
5869c6ff XL |
336 | report_bin_hex_error( |
337 | cx, | |
338 | e, | |
339 | attr::IntType::SignedInt(ty::ast_int_ty(t)), | |
340 | repr_str, | |
341 | v, | |
342 | negative, | |
343 | ); | |
48663c56 XL |
344 | return; |
345 | } | |
346 | ||
f2b60f7d FG |
347 | if lint_overflowing_range_endpoint(cx, lit, v, max, e, t.name_str()) { |
348 | // The overflowing literal lint was overridden. | |
349 | return; | |
48663c56 XL |
350 | } |
351 | ||
74b04a01 | 352 | cx.struct_span_lint(OVERFLOWING_LITERALS, e.span, |lint| { |
064997fb FG |
353 | let mut err = lint.build(fluent::lint::overflowing_int); |
354 | err.set_arg("ty", t.name_str()); | |
355 | err.set_arg( | |
356 | "lit", | |
6a06907d XL |
357 | cx.sess() |
358 | .source_map() | |
359 | .span_to_snippet(lit.span) | |
360 | .expect("must get snippet from literal"), | |
064997fb FG |
361 | ); |
362 | err.set_arg("min", min); | |
363 | err.set_arg("max", max); | |
364 | err.note(fluent::lint::note); | |
6a06907d | 365 | if let Some(sugg_ty) = |
5099ac24 | 366 | get_type_suggestion(cx.typeck_results().node_type(e.hir_id), v, negative) |
6a06907d | 367 | { |
064997fb FG |
368 | err.set_arg("suggestion_ty", sugg_ty); |
369 | err.help(fluent::lint::help); | |
6a06907d XL |
370 | } |
371 | err.emit(); | |
74b04a01 | 372 | }); |
48663c56 XL |
373 | } |
374 | } | |
375 | ||
f035d41b XL |
376 | fn lint_uint_literal<'tcx>( |
377 | cx: &LateContext<'tcx>, | |
dfeec247 | 378 | e: &'tcx hir::Expr<'tcx>, |
48663c56 | 379 | lit: &hir::Lit, |
5869c6ff | 380 | t: ty::UintTy, |
48663c56 | 381 | ) { |
29967ef6 | 382 | let uint_type = t.normalize(cx.sess().target.pointer_width); |
48663c56 XL |
383 | let (min, max) = uint_ty_range(uint_type); |
384 | let lit_val: u128 = match lit.node { | |
385 | // _v is u8, within range by definition | |
386 | ast::LitKind::Byte(_v) => return, | |
387 | ast::LitKind::Int(v, _) => v, | |
388 | _ => bug!(), | |
389 | }; | |
390 | if lit_val < min || lit_val > max { | |
dc9dc135 XL |
391 | let parent_id = cx.tcx.hir().get_parent_node(e.hir_id); |
392 | if let Node::Expr(par_e) = cx.tcx.hir().get(parent_id) { | |
e74abb32 | 393 | match par_e.kind { |
48663c56 | 394 | hir::ExprKind::Cast(..) => { |
1b1a35ee | 395 | if let ty::Char = cx.typeck_results().expr_ty(par_e).kind() { |
74b04a01 | 396 | cx.struct_span_lint(OVERFLOWING_LITERALS, par_e.span, |lint| { |
064997fb | 397 | lint.build(fluent::lint::only_cast_u8_to_char) |
74b04a01 XL |
398 | .span_suggestion( |
399 | par_e.span, | |
064997fb | 400 | fluent::lint::suggestion, |
74b04a01 XL |
401 | format!("'\\u{{{:X}}}'", lit_val), |
402 | Applicability::MachineApplicable, | |
403 | ) | |
404 | .emit(); | |
405 | }); | |
48663c56 XL |
406 | return; |
407 | } | |
408 | } | |
48663c56 XL |
409 | _ => {} |
410 | } | |
411 | } | |
f2b60f7d FG |
412 | if lint_overflowing_range_endpoint(cx, lit, lit_val, max, e, t.name_str()) { |
413 | // The overflowing literal lint was overridden. | |
414 | return; | |
415 | } | |
48663c56 | 416 | if let Some(repr_str) = get_bin_hex_repr(cx, lit) { |
5869c6ff XL |
417 | report_bin_hex_error( |
418 | cx, | |
419 | e, | |
420 | attr::IntType::UnsignedInt(ty::ast_uint_ty(t)), | |
421 | repr_str, | |
422 | lit_val, | |
423 | false, | |
424 | ); | |
48663c56 XL |
425 | return; |
426 | } | |
74b04a01 | 427 | cx.struct_span_lint(OVERFLOWING_LITERALS, e.span, |lint| { |
064997fb FG |
428 | lint.build(fluent::lint::overflowing_uint) |
429 | .set_arg("ty", t.name_str()) | |
430 | .set_arg( | |
431 | "lit", | |
ba9703b0 XL |
432 | cx.sess() |
433 | .source_map() | |
434 | .span_to_snippet(lit.span) | |
435 | .expect("must get snippet from literal"), | |
064997fb FG |
436 | ) |
437 | .set_arg("min", min) | |
438 | .set_arg("max", max) | |
439 | .note(fluent::lint::note) | |
5e7ed085 | 440 | .emit(); |
74b04a01 | 441 | }); |
48663c56 XL |
442 | } |
443 | } | |
444 | ||
f035d41b XL |
445 | fn lint_literal<'tcx>( |
446 | cx: &LateContext<'tcx>, | |
48663c56 | 447 | type_limits: &TypeLimits, |
dfeec247 | 448 | e: &'tcx hir::Expr<'tcx>, |
48663c56 XL |
449 | lit: &hir::Lit, |
450 | ) { | |
1b1a35ee | 451 | match *cx.typeck_results().node_type(e.hir_id).kind() { |
48663c56 XL |
452 | ty::Int(t) => { |
453 | match lit.node { | |
ba9703b0 | 454 | ast::LitKind::Int(v, ast::LitIntType::Signed(_) | ast::LitIntType::Unsuffixed) => { |
48663c56 XL |
455 | lint_int_literal(cx, type_limits, e, lit, t, v) |
456 | } | |
457 | _ => bug!(), | |
458 | }; | |
459 | } | |
dfeec247 | 460 | ty::Uint(t) => lint_uint_literal(cx, e, lit, t), |
48663c56 XL |
461 | ty::Float(t) => { |
462 | let is_infinite = match lit.node { | |
dfeec247 | 463 | ast::LitKind::Float(v, _) => match t { |
5869c6ff XL |
464 | ty::FloatTy::F32 => v.as_str().parse().map(f32::is_infinite), |
465 | ty::FloatTy::F64 => v.as_str().parse().map(f64::is_infinite), | |
dfeec247 | 466 | }, |
48663c56 XL |
467 | _ => bug!(), |
468 | }; | |
469 | if is_infinite == Ok(true) { | |
74b04a01 | 470 | cx.struct_span_lint(OVERFLOWING_LITERALS, e.span, |lint| { |
064997fb FG |
471 | lint.build(fluent::lint::overflowing_literal) |
472 | .set_arg("ty", t.name_str()) | |
473 | .set_arg( | |
474 | "lit", | |
ba9703b0 XL |
475 | cx.sess() |
476 | .source_map() | |
477 | .span_to_snippet(lit.span) | |
478 | .expect("must get snippet from literal"), | |
064997fb FG |
479 | ) |
480 | .note(fluent::lint::note) | |
ba9703b0 | 481 | .emit(); |
74b04a01 | 482 | }); |
48663c56 XL |
483 | } |
484 | } | |
485 | _ => {} | |
486 | } | |
487 | } | |
488 | ||
f035d41b XL |
489 | impl<'tcx> LateLintPass<'tcx> for TypeLimits { |
490 | fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx hir::Expr<'tcx>) { | |
e74abb32 | 491 | match e.kind { |
6a06907d | 492 | hir::ExprKind::Unary(hir::UnOp::Neg, ref expr) => { |
b039eaaf | 493 | // propagate negation, if the negation itself isn't negated |
ba9703b0 XL |
494 | if self.negated_expr_id != Some(e.hir_id) { |
495 | self.negated_expr_id = Some(expr.hir_id); | |
b039eaaf | 496 | } |
c30ab7b3 | 497 | } |
8faf50e0 | 498 | hir::ExprKind::Binary(binop, ref l, ref r) => { |
32a655c1 | 499 | if is_comparison(binop) && !check_limits(cx, binop, &l, &r) { |
74b04a01 | 500 | cx.struct_span_lint(UNUSED_COMPARISONS, e.span, |lint| { |
064997fb | 501 | lint.build(fluent::lint::unused_comparisons).emit(); |
74b04a01 | 502 | }); |
b039eaaf | 503 | } |
c30ab7b3 | 504 | } |
48663c56 XL |
505 | hir::ExprKind::Lit(ref lit) => lint_literal(cx, self, e, lit), |
506 | _ => {} | |
b039eaaf SL |
507 | }; |
508 | ||
c30ab7b3 | 509 | fn is_valid<T: cmp::PartialOrd>(binop: hir::BinOp, v: T, min: T, max: T) -> bool { |
b039eaaf | 510 | match binop.node { |
8faf50e0 XL |
511 | hir::BinOpKind::Lt => v > min && v <= max, |
512 | hir::BinOpKind::Le => v >= min && v < max, | |
513 | hir::BinOpKind::Gt => v >= min && v < max, | |
514 | hir::BinOpKind::Ge => v > min && v <= max, | |
515 | hir::BinOpKind::Eq | hir::BinOpKind::Ne => v >= min && v <= max, | |
c30ab7b3 | 516 | _ => bug!(), |
b039eaaf SL |
517 | } |
518 | } | |
519 | ||
520 | fn rev_binop(binop: hir::BinOp) -> hir::BinOp { | |
dfeec247 XL |
521 | source_map::respan( |
522 | binop.span, | |
523 | match binop.node { | |
524 | hir::BinOpKind::Lt => hir::BinOpKind::Gt, | |
525 | hir::BinOpKind::Le => hir::BinOpKind::Ge, | |
526 | hir::BinOpKind::Gt => hir::BinOpKind::Lt, | |
527 | hir::BinOpKind::Ge => hir::BinOpKind::Le, | |
528 | _ => return binop, | |
529 | }, | |
530 | ) | |
b039eaaf SL |
531 | } |
532 | ||
dfeec247 | 533 | fn check_limits( |
f035d41b | 534 | cx: &LateContext<'_>, |
dfeec247 XL |
535 | binop: hir::BinOp, |
536 | l: &hir::Expr<'_>, | |
537 | r: &hir::Expr<'_>, | |
538 | ) -> bool { | |
e74abb32 | 539 | let (lit, expr, swap) = match (&l.kind, &r.kind) { |
8faf50e0 XL |
540 | (&hir::ExprKind::Lit(_), _) => (l, r, true), |
541 | (_, &hir::ExprKind::Lit(_)) => (r, l, false), | |
c30ab7b3 | 542 | _ => return true, |
b039eaaf SL |
543 | }; |
544 | // Normalize the binop so that the literal is always on the RHS in | |
545 | // the comparison | |
c30ab7b3 | 546 | let norm_binop = if swap { rev_binop(binop) } else { binop }; |
1b1a35ee | 547 | match *cx.typeck_results().node_type(expr.hir_id).kind() { |
b7449926 | 548 | ty::Int(int_ty) => { |
b039eaaf | 549 | let (min, max) = int_ty_range(int_ty); |
e74abb32 | 550 | let lit_val: i128 = match lit.kind { |
dfeec247 | 551 | hir::ExprKind::Lit(ref li) => match li.node { |
ba9703b0 XL |
552 | ast::LitKind::Int( |
553 | v, | |
554 | ast::LitIntType::Signed(_) | ast::LitIntType::Unsuffixed, | |
555 | ) => v as i128, | |
dfeec247 | 556 | _ => return true, |
32a655c1 | 557 | }, |
dfeec247 | 558 | _ => bug!(), |
b039eaaf SL |
559 | }; |
560 | is_valid(norm_binop, lit_val, min, max) | |
561 | } | |
b7449926 | 562 | ty::Uint(uint_ty) => { |
dfeec247 | 563 | let (min, max): (u128, u128) = uint_ty_range(uint_ty); |
e74abb32 | 564 | let lit_val: u128 = match lit.kind { |
dfeec247 XL |
565 | hir::ExprKind::Lit(ref li) => match li.node { |
566 | ast::LitKind::Int(v, _) => v, | |
567 | _ => return true, | |
32a655c1 | 568 | }, |
dfeec247 | 569 | _ => bug!(), |
b039eaaf SL |
570 | }; |
571 | is_valid(norm_binop, lit_val, min, max) | |
572 | } | |
c30ab7b3 | 573 | _ => true, |
b039eaaf SL |
574 | } |
575 | } | |
576 | ||
577 | fn is_comparison(binop: hir::BinOp) -> bool { | |
29967ef6 XL |
578 | matches!( |
579 | binop.node, | |
dfeec247 | 580 | hir::BinOpKind::Eq |
29967ef6 XL |
581 | | hir::BinOpKind::Lt |
582 | | hir::BinOpKind::Le | |
583 | | hir::BinOpKind::Ne | |
584 | | hir::BinOpKind::Ge | |
585 | | hir::BinOpKind::Gt | |
586 | ) | |
b039eaaf | 587 | } |
b039eaaf SL |
588 | } |
589 | } | |
590 | ||
591 | declare_lint! { | |
1b1a35ee XL |
592 | /// The `improper_ctypes` lint detects incorrect use of types in foreign |
593 | /// modules. | |
594 | /// | |
595 | /// ### Example | |
596 | /// | |
597 | /// ```rust | |
598 | /// extern "C" { | |
599 | /// static STATIC: String; | |
600 | /// } | |
601 | /// ``` | |
602 | /// | |
603 | /// {{produces}} | |
604 | /// | |
605 | /// ### Explanation | |
606 | /// | |
607 | /// The compiler has several checks to verify that types used in `extern` | |
608 | /// blocks are safe and follow certain rules to ensure proper | |
609 | /// compatibility with the foreign interfaces. This lint is issued when it | |
610 | /// detects a probable mistake in a definition. The lint usually should | |
611 | /// provide a description of the issue, along with possibly a hint on how | |
612 | /// to resolve it. | |
b039eaaf SL |
613 | IMPROPER_CTYPES, |
614 | Warn, | |
615 | "proper use of libc types in foreign modules" | |
616 | } | |
617 | ||
f035d41b XL |
618 | declare_lint_pass!(ImproperCTypesDeclarations => [IMPROPER_CTYPES]); |
619 | ||
620 | declare_lint! { | |
1b1a35ee XL |
621 | /// The `improper_ctypes_definitions` lint detects incorrect use of |
622 | /// [`extern` function] definitions. | |
623 | /// | |
624 | /// [`extern` function]: https://doc.rust-lang.org/reference/items/functions.html#extern-function-qualifier | |
625 | /// | |
626 | /// ### Example | |
627 | /// | |
628 | /// ```rust | |
629 | /// # #![allow(unused)] | |
630 | /// pub extern "C" fn str_type(p: &str) { } | |
631 | /// ``` | |
632 | /// | |
633 | /// {{produces}} | |
634 | /// | |
635 | /// ### Explanation | |
636 | /// | |
637 | /// There are many parameter and return types that may be specified in an | |
638 | /// `extern` function that are not compatible with the given ABI. This | |
639 | /// lint is an alert that these types should not be used. The lint usually | |
640 | /// should provide a description of the issue, along with possibly a hint | |
641 | /// on how to resolve it. | |
f035d41b XL |
642 | IMPROPER_CTYPES_DEFINITIONS, |
643 | Warn, | |
644 | "proper use of libc types in foreign item definitions" | |
645 | } | |
646 | ||
647 | declare_lint_pass!(ImproperCTypesDefinitions => [IMPROPER_CTYPES_DEFINITIONS]); | |
648 | ||
3dfed10e | 649 | #[derive(Clone, Copy)] |
923072b8 | 650 | pub(crate) enum CItemKind { |
3dfed10e XL |
651 | Declaration, |
652 | Definition, | |
f035d41b | 653 | } |
532ac7d7 | 654 | |
dc9dc135 | 655 | struct ImproperCTypesVisitor<'a, 'tcx> { |
f035d41b | 656 | cx: &'a LateContext<'tcx>, |
3dfed10e | 657 | mode: CItemKind, |
b039eaaf SL |
658 | } |
659 | ||
0531ce1d | 660 | enum FfiResult<'tcx> { |
b039eaaf | 661 | FfiSafe, |
0531ce1d | 662 | FfiPhantom(Ty<'tcx>), |
064997fb | 663 | FfiUnsafe { ty: Ty<'tcx>, reason: DiagnosticMessage, help: Option<DiagnosticMessage> }, |
b039eaaf SL |
664 | } |
665 | ||
923072b8 FG |
666 | pub(crate) fn nonnull_optimization_guaranteed<'tcx>( |
667 | tcx: TyCtxt<'tcx>, | |
668 | def: ty::AdtDef<'tcx>, | |
669 | ) -> bool { | |
04454e1e | 670 | tcx.has_attr(def.did(), sym::rustc_nonnull_optimization_guaranteed) |
1b1a35ee XL |
671 | } |
672 | ||
673 | /// `repr(transparent)` structs can have a single non-ZST field, this function returns that | |
674 | /// field. | |
675 | pub fn transparent_newtype_field<'a, 'tcx>( | |
676 | tcx: TyCtxt<'tcx>, | |
677 | variant: &'a ty::VariantDef, | |
678 | ) -> Option<&'a ty::FieldDef> { | |
679 | let param_env = tcx.param_env(variant.def_id); | |
17df50a5 | 680 | variant.fields.iter().find(|field| { |
1b1a35ee | 681 | let field_ty = tcx.type_of(field.did); |
5869c6ff | 682 | let is_zst = tcx.layout_of(param_env.and(field_ty)).map_or(false, |layout| layout.is_zst()); |
17df50a5 XL |
683 | !is_zst |
684 | }) | |
1b1a35ee XL |
685 | } |
686 | ||
3dfed10e | 687 | /// Is type known to be non-null? |
6a06907d | 688 | fn ty_is_known_nonnull<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>, mode: CItemKind) -> bool { |
3dfed10e | 689 | let tcx = cx.tcx; |
1b1a35ee | 690 | match ty.kind() { |
3dfed10e XL |
691 | ty::FnPtr(_) => true, |
692 | ty::Ref(..) => true, | |
693 | ty::Adt(def, _) if def.is_box() && matches!(mode, CItemKind::Definition) => true, | |
5e7ed085 FG |
694 | ty::Adt(def, substs) if def.repr().transparent() && !def.is_union() => { |
695 | let marked_non_null = nonnull_optimization_guaranteed(tcx, *def); | |
3dfed10e | 696 | |
1b1a35ee | 697 | if marked_non_null { |
3dfed10e | 698 | return true; |
f9652781 | 699 | } |
1b1a35ee | 700 | |
064997fb FG |
701 | // `UnsafeCell` has its niche hidden. |
702 | if def.is_unsafe_cell() { | |
6a06907d XL |
703 | return false; |
704 | } | |
705 | ||
5e7ed085 | 706 | def.variants() |
17df50a5 XL |
707 | .iter() |
708 | .filter_map(|variant| transparent_newtype_field(cx.tcx, variant)) | |
709 | .any(|field| ty_is_known_nonnull(cx, field.ty(tcx, substs), mode)) | |
b039eaaf | 710 | } |
3dfed10e | 711 | _ => false, |
b039eaaf | 712 | } |
3dfed10e | 713 | } |
dc9dc135 | 714 | |
3dfed10e XL |
715 | /// Given a non-null scalar (or transparent) type `ty`, return the nullable version of that type. |
716 | /// If the type passed in was not scalar, returns None. | |
717 | fn get_nullable_type<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'tcx>> { | |
718 | let tcx = cx.tcx; | |
1b1a35ee | 719 | Some(match *ty.kind() { |
3dfed10e XL |
720 | ty::Adt(field_def, field_substs) => { |
721 | let inner_field_ty = { | |
f2b60f7d | 722 | let mut first_non_zst_ty = field_def |
5e7ed085 FG |
723 | .variants() |
724 | .iter() | |
725 | .filter_map(|v| transparent_newtype_field(cx.tcx, v)); | |
3dfed10e XL |
726 | debug_assert_eq!( |
727 | first_non_zst_ty.clone().count(), | |
728 | 1, | |
729 | "Wrong number of fields for transparent type" | |
730 | ); | |
731 | first_non_zst_ty | |
f2b60f7d | 732 | .next_back() |
3dfed10e XL |
733 | .expect("No non-zst fields in transparent type.") |
734 | .ty(tcx, field_substs) | |
735 | }; | |
736 | return get_nullable_type(cx, inner_field_ty); | |
737 | } | |
738 | ty::Int(ty) => tcx.mk_mach_int(ty), | |
739 | ty::Uint(ty) => tcx.mk_mach_uint(ty), | |
740 | ty::RawPtr(ty_mut) => tcx.mk_ptr(ty_mut), | |
741 | // As these types are always non-null, the nullable equivalent of | |
742 | // Option<T> of these types are their raw pointer counterparts. | |
743 | ty::Ref(_region, ty, mutbl) => tcx.mk_ptr(ty::TypeAndMut { ty, mutbl }), | |
744 | ty::FnPtr(..) => { | |
745 | // There is no nullable equivalent for Rust's function pointers -- you | |
746 | // must use an Option<fn(..) -> _> to represent it. | |
747 | ty | |
748 | } | |
749 | ||
750 | // We should only ever reach this case if ty_is_known_nonnull is extended | |
751 | // to other types. | |
752 | ref unhandled => { | |
753 | debug!( | |
754 | "get_nullable_type: Unhandled scalar kind: {:?} while checking {:?}", | |
755 | unhandled, ty | |
756 | ); | |
757 | return None; | |
758 | } | |
759 | }) | |
760 | } | |
761 | ||
762 | /// Check if this enum can be safely exported based on the "nullable pointer optimization". If it | |
1b1a35ee | 763 | /// can, return the type that `ty` can be safely converted to, otherwise return `None`. |
3dfed10e XL |
764 | /// Currently restricted to function pointers, boxes, references, `core::num::NonZero*`, |
765 | /// `core::ptr::NonNull`, and `#[repr(transparent)]` newtypes. | |
766 | /// FIXME: This duplicates code in codegen. | |
923072b8 | 767 | pub(crate) fn repr_nullable_ptr<'tcx>( |
3dfed10e XL |
768 | cx: &LateContext<'tcx>, |
769 | ty: Ty<'tcx>, | |
770 | ckind: CItemKind, | |
771 | ) -> Option<Ty<'tcx>> { | |
772 | debug!("is_repr_nullable_ptr(cx, ty = {:?})", ty); | |
1b1a35ee | 773 | if let ty::Adt(ty_def, substs) = ty.kind() { |
5e7ed085 | 774 | let field_ty = match &ty_def.variants().raw[..] { |
17df50a5 XL |
775 | [var_one, var_two] => match (&var_one.fields[..], &var_two.fields[..]) { |
776 | ([], [field]) | ([field], []) => field.ty(cx.tcx, substs), | |
777 | _ => return None, | |
778 | }, | |
779 | _ => return None, | |
f035d41b | 780 | }; |
dc9dc135 | 781 | |
3dfed10e XL |
782 | if !ty_is_known_nonnull(cx, field_ty, ckind) { |
783 | return None; | |
f035d41b | 784 | } |
dc9dc135 | 785 | |
3dfed10e XL |
786 | // At this point, the field's type is known to be nonnull and the parent enum is Option-like. |
787 | // If the computed size for the field and the enum are different, the nonnull optimization isn't | |
788 | // being applied (and we've got a problem somewhere). | |
789 | let compute_size_skeleton = |t| SizeSkeleton::compute(t, cx.tcx, cx.param_env).unwrap(); | |
f035d41b XL |
790 | if !compute_size_skeleton(ty).same_size(compute_size_skeleton(field_ty)) { |
791 | bug!("improper_ctypes: Option nonnull optimization not applied?"); | |
792 | } | |
dc9dc135 | 793 | |
3dfed10e XL |
794 | // Return the nullable type this Option-like enum can be safely represented with. |
795 | let field_ty_abi = &cx.layout_of(field_ty).unwrap().abi; | |
796 | if let Abi::Scalar(field_ty_scalar) = field_ty_abi { | |
04454e1e FG |
797 | match field_ty_scalar.valid_range(cx) { |
798 | WrappingRange { start: 0, end } | |
799 | if end == field_ty_scalar.size(&cx.tcx).unsigned_int_max() - 1 => | |
800 | { | |
5e7ed085 FG |
801 | return Some(get_nullable_type(cx, field_ty).unwrap()); |
802 | } | |
04454e1e | 803 | WrappingRange { start: 1, .. } => { |
3dfed10e XL |
804 | return Some(get_nullable_type(cx, field_ty).unwrap()); |
805 | } | |
04454e1e FG |
806 | WrappingRange { start, end } => { |
807 | unreachable!("Unhandled start and end range: ({}, {})", start, end) | |
808 | } | |
3dfed10e XL |
809 | }; |
810 | } | |
f035d41b | 811 | } |
3dfed10e XL |
812 | None |
813 | } | |
b039eaaf | 814 | |
3dfed10e | 815 | impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { |
60c5eb7d XL |
816 | /// Check if the type is array and emit an unsafe type lint. |
817 | fn check_for_array_ty(&mut self, sp: Span, ty: Ty<'tcx>) -> bool { | |
1b1a35ee | 818 | if let ty::Array(..) = ty.kind() { |
60c5eb7d XL |
819 | self.emit_ffi_unsafe_type_lint( |
820 | ty, | |
821 | sp, | |
064997fb FG |
822 | fluent::lint::improper_ctypes_array_reason, |
823 | Some(fluent::lint::improper_ctypes_array_help), | |
60c5eb7d XL |
824 | ); |
825 | true | |
826 | } else { | |
827 | false | |
828 | } | |
829 | } | |
830 | ||
f035d41b XL |
831 | /// Checks if the given field's type is "ffi-safe". |
832 | fn check_field_type_for_ffi( | |
833 | &self, | |
834 | cache: &mut FxHashSet<Ty<'tcx>>, | |
835 | field: &ty::FieldDef, | |
836 | substs: SubstsRef<'tcx>, | |
837 | ) -> FfiResult<'tcx> { | |
838 | let field_ty = field.ty(self.cx.tcx, substs); | |
839 | if field_ty.has_opaque_types() { | |
840 | self.check_type_for_ffi(cache, field_ty) | |
841 | } else { | |
842 | let field_ty = self.cx.tcx.normalize_erasing_regions(self.cx.param_env, field_ty); | |
843 | self.check_type_for_ffi(cache, field_ty) | |
844 | } | |
845 | } | |
846 | ||
847 | /// Checks if the given `VariantDef`'s field types are "ffi-safe". | |
848 | fn check_variant_for_ffi( | |
849 | &self, | |
850 | cache: &mut FxHashSet<Ty<'tcx>>, | |
851 | ty: Ty<'tcx>, | |
5e7ed085 | 852 | def: ty::AdtDef<'tcx>, |
f035d41b XL |
853 | variant: &ty::VariantDef, |
854 | substs: SubstsRef<'tcx>, | |
855 | ) -> FfiResult<'tcx> { | |
856 | use FfiResult::*; | |
857 | ||
5e7ed085 | 858 | if def.repr().transparent() { |
c295e0f8 | 859 | // Can assume that at most one field is not a ZST, so only check |
f035d41b | 860 | // that field's type for FFI-safety. |
1b1a35ee | 861 | if let Some(field) = transparent_newtype_field(self.cx.tcx, variant) { |
f035d41b XL |
862 | self.check_field_type_for_ffi(cache, field, substs) |
863 | } else { | |
c295e0f8 XL |
864 | // All fields are ZSTs; this means that the type should behave |
865 | // like (), which is FFI-unsafe | |
064997fb | 866 | FfiUnsafe { ty, reason: fluent::lint::improper_ctypes_struct_zst, help: None } |
f035d41b XL |
867 | } |
868 | } else { | |
869 | // We can't completely trust repr(C) markings; make sure the fields are | |
870 | // actually safe. | |
871 | let mut all_phantom = !variant.fields.is_empty(); | |
872 | for field in &variant.fields { | |
873 | match self.check_field_type_for_ffi(cache, &field, substs) { | |
874 | FfiSafe => { | |
875 | all_phantom = false; | |
876 | } | |
877 | FfiPhantom(..) if def.is_enum() => { | |
878 | return FfiUnsafe { | |
879 | ty, | |
064997fb | 880 | reason: fluent::lint::improper_ctypes_enum_phantomdata, |
f035d41b XL |
881 | help: None, |
882 | }; | |
883 | } | |
884 | FfiPhantom(..) => {} | |
885 | r => return r, | |
886 | } | |
887 | } | |
888 | ||
889 | if all_phantom { FfiPhantom(ty) } else { FfiSafe } | |
890 | } | |
891 | } | |
892 | ||
9fa01778 | 893 | /// Checks if the given type is "ffi-safe" (has a stable, well-defined |
b039eaaf | 894 | /// representation which can be exported to C code). |
dfeec247 | 895 | fn check_type_for_ffi(&self, cache: &mut FxHashSet<Ty<'tcx>>, ty: Ty<'tcx>) -> FfiResult<'tcx> { |
9fa01778 | 896 | use FfiResult::*; |
8bb4bdeb | 897 | |
3dfed10e | 898 | let tcx = self.cx.tcx; |
b039eaaf SL |
899 | |
900 | // Protect against infinite recursion, for example | |
901 | // `struct S(*mut S);`. | |
902 | // FIXME: A recursion limit is necessary as well, for irregular | |
b7449926 | 903 | // recursive types. |
b039eaaf SL |
904 | if !cache.insert(ty) { |
905 | return FfiSafe; | |
906 | } | |
907 | ||
fc512014 | 908 | match *ty.kind() { |
b7449926 | 909 | ty::Adt(def, substs) => { |
17df50a5 XL |
910 | if def.is_box() && matches!(self.mode, CItemKind::Definition) { |
911 | if ty.boxed_ty().is_sized(tcx.at(DUMMY_SP), self.cx.param_env) { | |
912 | return FfiSafe; | |
913 | } else { | |
914 | return FfiUnsafe { | |
915 | ty, | |
064997fb | 916 | reason: fluent::lint::improper_ctypes_box, |
17df50a5 XL |
917 | help: None, |
918 | }; | |
919 | } | |
920 | } | |
8bb4bdeb | 921 | if def.is_phantom_data() { |
0531ce1d | 922 | return FfiPhantom(ty); |
8bb4bdeb | 923 | } |
c30ab7b3 | 924 | match def.adt_kind() { |
f035d41b | 925 | AdtKind::Struct | AdtKind::Union => { |
5e7ed085 | 926 | if !def.repr().c() && !def.repr().transparent() { |
0531ce1d | 927 | return FfiUnsafe { |
e1599b0c | 928 | ty, |
064997fb FG |
929 | reason: if def.is_struct() { |
930 | fluent::lint::improper_ctypes_struct_layout_reason | |
931 | } else { | |
932 | fluent::lint::improper_ctypes_union_layout_reason | |
933 | }, | |
934 | help: if def.is_struct() { | |
935 | Some(fluent::lint::improper_ctypes_struct_layout_help) | |
936 | } else { | |
937 | Some(fluent::lint::improper_ctypes_union_layout_help) | |
938 | }, | |
0531ce1d | 939 | }; |
c30ab7b3 | 940 | } |
b039eaaf | 941 | |
e74abb32 XL |
942 | let is_non_exhaustive = |
943 | def.non_enum_variant().is_field_list_non_exhaustive(); | |
5e7ed085 | 944 | if is_non_exhaustive && !def.did().is_local() { |
e74abb32 XL |
945 | return FfiUnsafe { |
946 | ty, | |
064997fb FG |
947 | reason: if def.is_struct() { |
948 | fluent::lint::improper_ctypes_struct_non_exhaustive | |
949 | } else { | |
950 | fluent::lint::improper_ctypes_union_non_exhaustive | |
951 | }, | |
e74abb32 XL |
952 | help: None, |
953 | }; | |
954 | } | |
955 | ||
2c00a5a8 | 956 | if def.non_enum_variant().fields.is_empty() { |
0531ce1d | 957 | return FfiUnsafe { |
e1599b0c | 958 | ty, |
064997fb FG |
959 | reason: if def.is_struct() { |
960 | fluent::lint::improper_ctypes_struct_fieldless_reason | |
961 | } else { | |
962 | fluent::lint::improper_ctypes_union_fieldless_reason | |
963 | }, | |
964 | help: if def.is_struct() { | |
965 | Some(fluent::lint::improper_ctypes_struct_fieldless_help) | |
966 | } else { | |
967 | Some(fluent::lint::improper_ctypes_union_fieldless_help) | |
968 | }, | |
0531ce1d | 969 | }; |
8bb4bdeb XL |
970 | } |
971 | ||
f035d41b | 972 | self.check_variant_for_ffi(cache, ty, def, def.non_enum_variant(), substs) |
b039eaaf | 973 | } |
c30ab7b3 | 974 | AdtKind::Enum => { |
5e7ed085 | 975 | if def.variants().is_empty() { |
c30ab7b3 SL |
976 | // Empty enums are okay... although sort of useless. |
977 | return FfiSafe; | |
978 | } | |
9e0c209e | 979 | |
c30ab7b3 SL |
980 | // Check for a repr() attribute to specify the size of the |
981 | // discriminant. | |
5e7ed085 FG |
982 | if !def.repr().c() && !def.repr().transparent() && def.repr().int.is_none() |
983 | { | |
8bb4bdeb | 984 | // Special-case types like `Option<extern fn()>`. |
3dfed10e | 985 | if repr_nullable_ptr(self.cx, ty, self.mode).is_none() { |
0531ce1d | 986 | return FfiUnsafe { |
e1599b0c | 987 | ty, |
064997fb FG |
988 | reason: fluent::lint::improper_ctypes_enum_repr_reason, |
989 | help: Some(fluent::lint::improper_ctypes_enum_repr_help), | |
0531ce1d | 990 | }; |
9e0c209e | 991 | } |
8bb4bdeb | 992 | } |
c30ab7b3 | 993 | |
5e7ed085 | 994 | if def.is_variant_list_non_exhaustive() && !def.did().is_local() { |
e74abb32 XL |
995 | return FfiUnsafe { |
996 | ty, | |
064997fb | 997 | reason: fluent::lint::improper_ctypes_non_exhaustive, |
e74abb32 XL |
998 | help: None, |
999 | }; | |
1000 | } | |
1001 | ||
c30ab7b3 | 1002 | // Check the contained variants. |
5e7ed085 | 1003 | for variant in def.variants() { |
e74abb32 XL |
1004 | let is_non_exhaustive = variant.is_field_list_non_exhaustive(); |
1005 | if is_non_exhaustive && !variant.def_id.is_local() { | |
1006 | return FfiUnsafe { | |
1007 | ty, | |
064997fb | 1008 | reason: fluent::lint::improper_ctypes_non_exhaustive_variant, |
e74abb32 XL |
1009 | help: None, |
1010 | }; | |
1011 | } | |
1012 | ||
f035d41b XL |
1013 | match self.check_variant_for_ffi(cache, ty, def, variant, substs) { |
1014 | FfiSafe => (), | |
1015 | r => return r, | |
9e0c209e | 1016 | } |
b039eaaf | 1017 | } |
f035d41b | 1018 | |
c30ab7b3 | 1019 | FfiSafe |
b039eaaf SL |
1020 | } |
1021 | } | |
c30ab7b3 | 1022 | } |
b039eaaf | 1023 | |
b7449926 | 1024 | ty::Char => FfiUnsafe { |
e1599b0c | 1025 | ty, |
064997fb FG |
1026 | reason: fluent::lint::improper_ctypes_char_reason, |
1027 | help: Some(fluent::lint::improper_ctypes_char_help), | |
0531ce1d | 1028 | }, |
b039eaaf | 1029 | |
064997fb FG |
1030 | ty::Int(ty::IntTy::I128) | ty::Uint(ty::UintTy::U128) => { |
1031 | FfiUnsafe { ty, reason: fluent::lint::improper_ctypes_128bit, help: None } | |
1032 | } | |
ea8adc8c | 1033 | |
b039eaaf | 1034 | // Primitive types with a stable representation. |
b7449926 | 1035 | ty::Bool | ty::Int(..) | ty::Uint(..) | ty::Float(..) | ty::Never => FfiSafe, |
b039eaaf | 1036 | |
b7449926 | 1037 | ty::Slice(_) => FfiUnsafe { |
e1599b0c | 1038 | ty, |
064997fb FG |
1039 | reason: fluent::lint::improper_ctypes_slice_reason, |
1040 | help: Some(fluent::lint::improper_ctypes_slice_help), | |
0531ce1d XL |
1041 | }, |
1042 | ||
dfeec247 | 1043 | ty::Dynamic(..) => { |
064997fb | 1044 | FfiUnsafe { ty, reason: fluent::lint::improper_ctypes_dyn, help: None } |
dfeec247 | 1045 | } |
0531ce1d | 1046 | |
b7449926 | 1047 | ty::Str => FfiUnsafe { |
e1599b0c | 1048 | ty, |
064997fb FG |
1049 | reason: fluent::lint::improper_ctypes_str_reason, |
1050 | help: Some(fluent::lint::improper_ctypes_str_help), | |
0531ce1d XL |
1051 | }, |
1052 | ||
b7449926 | 1053 | ty::Tuple(..) => FfiUnsafe { |
e1599b0c | 1054 | ty, |
064997fb FG |
1055 | reason: fluent::lint::improper_ctypes_tuple_reason, |
1056 | help: Some(fluent::lint::improper_ctypes_tuple_help), | |
0531ce1d | 1057 | }, |
b039eaaf | 1058 | |
f035d41b XL |
1059 | ty::RawPtr(ty::TypeAndMut { ty, .. }) | ty::Ref(_, ty, _) |
1060 | if { | |
3dfed10e | 1061 | matches!(self.mode, CItemKind::Definition) |
f035d41b XL |
1062 | && ty.is_sized(self.cx.tcx.at(DUMMY_SP), self.cx.param_env) |
1063 | } => | |
1064 | { | |
1065 | FfiSafe | |
1066 | } | |
1067 | ||
c295e0f8 XL |
1068 | ty::RawPtr(ty::TypeAndMut { ty, .. }) |
1069 | if match ty.kind() { | |
1070 | ty::Tuple(tuple) => tuple.is_empty(), | |
1071 | _ => false, | |
1072 | } => | |
1073 | { | |
1074 | FfiSafe | |
1075 | } | |
1076 | ||
dfeec247 XL |
1077 | ty::RawPtr(ty::TypeAndMut { ty, .. }) | ty::Ref(_, ty, _) => { |
1078 | self.check_type_for_ffi(cache, ty) | |
1079 | } | |
b039eaaf | 1080 | |
60c5eb7d | 1081 | ty::Array(inner_ty, _) => self.check_type_for_ffi(cache, inner_ty), |
b039eaaf | 1082 | |
b7449926 | 1083 | ty::FnPtr(sig) => { |
f035d41b XL |
1084 | if self.is_internal_abi(sig.abi()) { |
1085 | return FfiUnsafe { | |
1086 | ty, | |
064997fb FG |
1087 | reason: fluent::lint::improper_ctypes_fnptr_reason, |
1088 | help: Some(fluent::lint::improper_ctypes_fnptr_help), | |
f035d41b | 1089 | }; |
b039eaaf SL |
1090 | } |
1091 | ||
fc512014 | 1092 | let sig = tcx.erase_late_bound_regions(sig); |
b7449926 | 1093 | if !sig.output().is_unit() { |
476ff2be | 1094 | let r = self.check_type_for_ffi(cache, sig.output()); |
5bcae85e SL |
1095 | match r { |
1096 | FfiSafe => {} | |
c30ab7b3 SL |
1097 | _ => { |
1098 | return r; | |
1099 | } | |
b039eaaf SL |
1100 | } |
1101 | } | |
476ff2be | 1102 | for arg in sig.inputs() { |
5099ac24 | 1103 | let r = self.check_type_for_ffi(cache, *arg); |
b039eaaf SL |
1104 | match r { |
1105 | FfiSafe => {} | |
c30ab7b3 SL |
1106 | _ => { |
1107 | return r; | |
1108 | } | |
b039eaaf SL |
1109 | } |
1110 | } | |
1111 | FfiSafe | |
1112 | } | |
1113 | ||
b7449926 XL |
1114 | ty::Foreign(..) => FfiSafe, |
1115 | ||
f035d41b XL |
1116 | // While opaque types are checked for earlier, if a projection in a struct field |
1117 | // normalizes to an opaque type, then it will reach this branch. | |
1118 | ty::Opaque(..) => { | |
064997fb | 1119 | FfiUnsafe { ty, reason: fluent::lint::improper_ctypes_opaque, help: None } |
f035d41b XL |
1120 | } |
1121 | ||
1122 | // `extern "C" fn` functions can have type parameters, which may or may not be FFI-safe, | |
1123 | // so they are currently ignored for the purposes of this lint. | |
3dfed10e | 1124 | ty::Param(..) | ty::Projection(..) if matches!(self.mode, CItemKind::Definition) => { |
f035d41b XL |
1125 | FfiSafe |
1126 | } | |
1127 | ||
dfeec247 | 1128 | ty::Param(..) |
f035d41b | 1129 | | ty::Projection(..) |
dfeec247 XL |
1130 | | ty::Infer(..) |
1131 | | ty::Bound(..) | |
f035d41b | 1132 | | ty::Error(_) |
dfeec247 XL |
1133 | | ty::Closure(..) |
1134 | | ty::Generator(..) | |
1135 | | ty::GeneratorWitness(..) | |
1136 | | ty::Placeholder(..) | |
dfeec247 | 1137 | | ty::FnDef(..) => bug!("unexpected type in foreign function: {:?}", ty), |
e1599b0c XL |
1138 | } |
1139 | } | |
1140 | ||
1141 | fn emit_ffi_unsafe_type_lint( | |
1142 | &mut self, | |
1143 | ty: Ty<'tcx>, | |
1144 | sp: Span, | |
064997fb FG |
1145 | note: DiagnosticMessage, |
1146 | help: Option<DiagnosticMessage>, | |
e1599b0c | 1147 | ) { |
f035d41b | 1148 | let lint = match self.mode { |
3dfed10e XL |
1149 | CItemKind::Declaration => IMPROPER_CTYPES, |
1150 | CItemKind::Definition => IMPROPER_CTYPES_DEFINITIONS, | |
f035d41b XL |
1151 | }; |
1152 | ||
1153 | self.cx.struct_span_lint(lint, sp, |lint| { | |
1154 | let item_description = match self.mode { | |
3dfed10e XL |
1155 | CItemKind::Declaration => "block", |
1156 | CItemKind::Definition => "fn", | |
f035d41b | 1157 | }; |
064997fb FG |
1158 | let mut diag = lint.build(fluent::lint::improper_ctypes); |
1159 | diag.set_arg("ty", ty); | |
1160 | diag.set_arg("desc", item_description); | |
1161 | diag.span_label(sp, fluent::lint::label); | |
74b04a01 XL |
1162 | if let Some(help) = help { |
1163 | diag.help(help); | |
e1599b0c | 1164 | } |
74b04a01 | 1165 | diag.note(note); |
1b1a35ee | 1166 | if let ty::Adt(def, _) = ty.kind() { |
5e7ed085 | 1167 | if let Some(sp) = self.cx.tcx.hir().span_if_local(def.did()) { |
064997fb | 1168 | diag.span_note(sp, fluent::lint::note); |
74b04a01 XL |
1169 | } |
1170 | } | |
1171 | diag.emit(); | |
1172 | }); | |
e1599b0c XL |
1173 | } |
1174 | ||
1175 | fn check_for_opaque_ty(&mut self, sp: Span, ty: Ty<'tcx>) -> bool { | |
f035d41b XL |
1176 | struct ProhibitOpaqueTypes<'a, 'tcx> { |
1177 | cx: &'a LateContext<'tcx>, | |
fc512014 | 1178 | } |
e1599b0c | 1179 | |
064997fb | 1180 | impl<'a, 'tcx> ty::visit::TypeVisitor<'tcx> for ProhibitOpaqueTypes<'a, 'tcx> { |
fc512014 XL |
1181 | type BreakTy = Ty<'tcx>; |
1182 | ||
1183 | fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> { | |
1b1a35ee | 1184 | match ty.kind() { |
fc512014 | 1185 | ty::Opaque(..) => ControlFlow::Break(ty), |
f035d41b XL |
1186 | // Consider opaque types within projections FFI-safe if they do not normalize |
1187 | // to more opaque types. | |
1188 | ty::Projection(..) => { | |
1189 | let ty = self.cx.tcx.normalize_erasing_regions(self.cx.param_env, ty); | |
1190 | ||
94222f64 | 1191 | // If `ty` is an opaque type directly then `super_visit_with` won't invoke |
f035d41b | 1192 | // this function again. |
29967ef6 XL |
1193 | if ty.has_opaque_types() { |
1194 | self.visit_ty(ty) | |
1195 | } else { | |
1196 | ControlFlow::CONTINUE | |
1197 | } | |
f035d41b XL |
1198 | } |
1199 | _ => ty.super_visit_with(self), | |
e1599b0c XL |
1200 | } |
1201 | } | |
1202 | } | |
1203 | ||
fc512014 | 1204 | if let Some(ty) = ty.visit_with(&mut ProhibitOpaqueTypes { cx: self.cx }).break_value() { |
064997fb | 1205 | self.emit_ffi_unsafe_type_lint(ty, sp, fluent::lint::improper_ctypes_opaque, None); |
e1599b0c XL |
1206 | true |
1207 | } else { | |
1208 | false | |
b039eaaf SL |
1209 | } |
1210 | } | |
1211 | ||
f035d41b XL |
1212 | fn check_type_for_ffi_and_report_errors( |
1213 | &mut self, | |
1214 | sp: Span, | |
1215 | ty: Ty<'tcx>, | |
1216 | is_static: bool, | |
1217 | is_return_type: bool, | |
1218 | ) { | |
e1599b0c XL |
1219 | // We have to check for opaque types before `normalize_erasing_regions`, |
1220 | // which will replace opaque types with their underlying concrete type. | |
1221 | if self.check_for_opaque_ty(sp, ty) { | |
1222 | // We've already emitted an error due to an opaque type. | |
1223 | return; | |
1224 | } | |
1225 | ||
54a0048b SL |
1226 | // it is only OK to use this function because extern fns cannot have |
1227 | // any generic types right now: | |
f035d41b XL |
1228 | let ty = self.cx.tcx.normalize_erasing_regions(self.cx.param_env, ty); |
1229 | ||
1230 | // C doesn't really support passing arrays by value - the only way to pass an array by value | |
1231 | // is through a struct. So, first test that the top level isn't an array, and then | |
1232 | // recursively check the types inside. | |
60c5eb7d XL |
1233 | if !is_static && self.check_for_array_ty(sp, ty) { |
1234 | return; | |
1235 | } | |
b039eaaf | 1236 | |
f035d41b XL |
1237 | // Don't report FFI errors for unit return types. This check exists here, and not in |
1238 | // `check_foreign_fn` (where it would make more sense) so that normalization has definitely | |
1239 | // happened. | |
1240 | if is_return_type && ty.is_unit() { | |
1241 | return; | |
1242 | } | |
1243 | ||
0bf4aa26 | 1244 | match self.check_type_for_ffi(&mut FxHashSet::default(), ty) { |
b039eaaf | 1245 | FfiResult::FfiSafe => {} |
0531ce1d | 1246 | FfiResult::FfiPhantom(ty) => { |
064997fb FG |
1247 | self.emit_ffi_unsafe_type_lint( |
1248 | ty, | |
1249 | sp, | |
1250 | fluent::lint::improper_ctypes_only_phantomdata, | |
1251 | None, | |
1252 | ); | |
9e0c209e | 1253 | } |
f035d41b XL |
1254 | // If `ty` is a `repr(transparent)` newtype, and the non-zero-sized type is a generic |
1255 | // argument, which after substitution, is `()`, then this branch can be hit. | |
3dfed10e | 1256 | FfiResult::FfiUnsafe { ty, .. } if is_return_type && ty.is_unit() => {} |
e1599b0c | 1257 | FfiResult::FfiUnsafe { ty, reason, help } => { |
064997fb | 1258 | self.emit_ffi_unsafe_type_lint(ty, sp, reason, help); |
b039eaaf SL |
1259 | } |
1260 | } | |
1261 | } | |
b039eaaf | 1262 | |
dfeec247 | 1263 | fn check_foreign_fn(&mut self, id: hir::HirId, decl: &hir::FnDecl<'_>) { |
416331ca | 1264 | let def_id = self.cx.tcx.hir().local_def_id(id); |
041b39d2 | 1265 | let sig = self.cx.tcx.fn_sig(def_id); |
fc512014 | 1266 | let sig = self.cx.tcx.erase_late_bound_regions(sig); |
54a0048b | 1267 | |
cdc7bbd5 | 1268 | for (input_ty, input_hir) in iter::zip(sig.inputs(), decl.inputs) { |
5099ac24 | 1269 | self.check_type_for_ffi_and_report_errors(input_hir.span, *input_ty, false, false); |
54a0048b SL |
1270 | } |
1271 | ||
74b04a01 | 1272 | if let hir::FnRetTy::Return(ref ret_hir) = decl.output { |
476ff2be | 1273 | let ret_ty = sig.output(); |
f035d41b | 1274 | self.check_type_for_ffi_and_report_errors(ret_hir.span, ret_ty, false, true); |
b039eaaf SL |
1275 | } |
1276 | } | |
54a0048b | 1277 | |
532ac7d7 | 1278 | fn check_foreign_static(&mut self, id: hir::HirId, span: Span) { |
416331ca | 1279 | let def_id = self.cx.tcx.hir().local_def_id(id); |
7cac9316 | 1280 | let ty = self.cx.tcx.type_of(def_id); |
f035d41b | 1281 | self.check_type_for_ffi_and_report_errors(span, ty, true, false); |
54a0048b | 1282 | } |
b039eaaf | 1283 | |
3dfed10e | 1284 | fn is_internal_abi(&self, abi: SpecAbi) -> bool { |
29967ef6 XL |
1285 | matches!( |
1286 | abi, | |
1287 | SpecAbi::Rust | SpecAbi::RustCall | SpecAbi::RustIntrinsic | SpecAbi::PlatformIntrinsic | |
1288 | ) | |
f035d41b XL |
1289 | } |
1290 | } | |
1291 | ||
1292 | impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDeclarations { | |
1293 | fn check_foreign_item(&mut self, cx: &LateContext<'_>, it: &hir::ForeignItem<'_>) { | |
3dfed10e | 1294 | let mut vis = ImproperCTypesVisitor { cx, mode: CItemKind::Declaration }; |
6a06907d | 1295 | let abi = cx.tcx.hir().get_foreign_abi(it.hir_id()); |
f035d41b XL |
1296 | |
1297 | if !vis.is_internal_abi(abi) { | |
e74abb32 | 1298 | match it.kind { |
b7449926 | 1299 | hir::ForeignItemKind::Fn(ref decl, _, _) => { |
6a06907d | 1300 | vis.check_foreign_fn(it.hir_id(), decl); |
b7449926 XL |
1301 | } |
1302 | hir::ForeignItemKind::Static(ref ty, _) => { | |
6a06907d | 1303 | vis.check_foreign_static(it.hir_id(), ty.span); |
b039eaaf | 1304 | } |
dfeec247 | 1305 | hir::ForeignItemKind::Type => (), |
b039eaaf | 1306 | } |
b039eaaf SL |
1307 | } |
1308 | } | |
1309 | } | |
5bcae85e | 1310 | |
f035d41b XL |
1311 | impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDefinitions { |
1312 | fn check_fn( | |
1313 | &mut self, | |
1314 | cx: &LateContext<'tcx>, | |
1315 | kind: hir::intravisit::FnKind<'tcx>, | |
1316 | decl: &'tcx hir::FnDecl<'_>, | |
1317 | _: &'tcx hir::Body<'_>, | |
1318 | _: Span, | |
1319 | hir_id: hir::HirId, | |
1320 | ) { | |
1321 | use hir::intravisit::FnKind; | |
1322 | ||
1323 | let abi = match kind { | |
1324 | FnKind::ItemFn(_, _, header, ..) => header.abi, | |
1325 | FnKind::Method(_, sig, ..) => sig.header.abi, | |
1326 | _ => return, | |
1327 | }; | |
1328 | ||
3dfed10e | 1329 | let mut vis = ImproperCTypesVisitor { cx, mode: CItemKind::Definition }; |
f035d41b XL |
1330 | if !vis.is_internal_abi(abi) { |
1331 | vis.check_foreign_fn(hir_id, decl); | |
1332 | } | |
1333 | } | |
1334 | } | |
1335 | ||
532ac7d7 | 1336 | declare_lint_pass!(VariantSizeDifferences => [VARIANT_SIZE_DIFFERENCES]); |
5bcae85e | 1337 | |
f035d41b XL |
1338 | impl<'tcx> LateLintPass<'tcx> for VariantSizeDifferences { |
1339 | fn check_item(&mut self, cx: &LateContext<'_>, it: &hir::Item<'_>) { | |
e74abb32 | 1340 | if let hir::ItemKind::Enum(ref enum_definition, _) = it.kind { |
6a06907d | 1341 | let t = cx.tcx.type_of(it.def_id); |
fc512014 | 1342 | let ty = cx.tcx.erase_regions(t); |
5e7ed085 | 1343 | let Ok(layout) = cx.layout_of(ty) else { return }; |
a2a8927a | 1344 | let Variants::Multiple { |
c295e0f8 | 1345 | tag_encoding: TagEncoding::Direct, tag, ref variants, .. |
a2a8927a XL |
1346 | } = &layout.variants else { |
1347 | return | |
532ac7d7 XL |
1348 | }; |
1349 | ||
04454e1e | 1350 | let tag_size = tag.size(&cx.tcx).bytes(); |
532ac7d7 | 1351 | |
dfeec247 XL |
1352 | debug!( |
1353 | "enum `{}` is {} bytes large with layout:\n{:#?}", | |
1354 | t, | |
1355 | layout.size.bytes(), | |
1356 | layout | |
1357 | ); | |
532ac7d7 | 1358 | |
cdc7bbd5 | 1359 | let (largest, slargest, largest_index) = iter::zip(enum_definition.variants, variants) |
532ac7d7 | 1360 | .map(|(variant, variant_layout)| { |
f035d41b | 1361 | // Subtract the size of the enum tag. |
5e7ed085 | 1362 | let bytes = variant_layout.size().bytes().saturating_sub(tag_size); |
532ac7d7 | 1363 | |
dfeec247 | 1364 | debug!("- variant `{}` is {} bytes large", variant.ident, bytes); |
532ac7d7 XL |
1365 | bytes |
1366 | }) | |
1367 | .enumerate() | |
dfeec247 XL |
1368 | .fold((0, 0, 0), |(l, s, li), (idx, size)| { |
1369 | if size > l { | |
1370 | (size, l, idx) | |
1371 | } else if size > s { | |
1372 | (l, size, li) | |
1373 | } else { | |
1374 | (l, s, li) | |
1375 | } | |
532ac7d7 XL |
1376 | }); |
1377 | ||
1378 | // We only warn if the largest variant is at least thrice as large as | |
1379 | // the second-largest. | |
1380 | if largest > slargest * 3 && slargest > 0 { | |
74b04a01 | 1381 | cx.struct_span_lint( |
dfeec247 XL |
1382 | VARIANT_SIZE_DIFFERENCES, |
1383 | enum_definition.variants[largest_index].span, | |
74b04a01 | 1384 | |lint| { |
064997fb FG |
1385 | lint.build(fluent::lint::variant_size_differences) |
1386 | .set_arg("largest", largest) | |
1387 | .emit(); | |
74b04a01 | 1388 | }, |
dfeec247 | 1389 | ); |
5bcae85e SL |
1390 | } |
1391 | } | |
1392 | } | |
1393 | } | |
94222f64 XL |
1394 | |
1395 | declare_lint! { | |
1396 | /// The `invalid_atomic_ordering` lint detects passing an `Ordering` | |
1397 | /// to an atomic operation that does not support that ordering. | |
1398 | /// | |
1399 | /// ### Example | |
1400 | /// | |
1401 | /// ```rust,compile_fail | |
1402 | /// # use core::sync::atomic::{AtomicU8, Ordering}; | |
1403 | /// let atom = AtomicU8::new(0); | |
1404 | /// let value = atom.load(Ordering::Release); | |
1405 | /// # let _ = value; | |
1406 | /// ``` | |
1407 | /// | |
1408 | /// {{produces}} | |
1409 | /// | |
1410 | /// ### Explanation | |
1411 | /// | |
1412 | /// Some atomic operations are only supported for a subset of the | |
1413 | /// `atomic::Ordering` variants. Passing an unsupported variant will cause | |
1414 | /// an unconditional panic at runtime, which is detected by this lint. | |
1415 | /// | |
1416 | /// This lint will trigger in the following cases: (where `AtomicType` is an | |
1417 | /// atomic type from `core::sync::atomic`, such as `AtomicBool`, | |
1418 | /// `AtomicPtr`, `AtomicUsize`, or any of the other integer atomics). | |
1419 | /// | |
1420 | /// - Passing `Ordering::Acquire` or `Ordering::AcqRel` to | |
1421 | /// `AtomicType::store`. | |
1422 | /// | |
1423 | /// - Passing `Ordering::Release` or `Ordering::AcqRel` to | |
1424 | /// `AtomicType::load`. | |
1425 | /// | |
1426 | /// - Passing `Ordering::Relaxed` to `core::sync::atomic::fence` or | |
1427 | /// `core::sync::atomic::compiler_fence`. | |
1428 | /// | |
1429 | /// - Passing `Ordering::Release` or `Ordering::AcqRel` as the failure | |
1430 | /// ordering for any of `AtomicType::compare_exchange`, | |
1431 | /// `AtomicType::compare_exchange_weak`, or `AtomicType::fetch_update`. | |
94222f64 XL |
1432 | INVALID_ATOMIC_ORDERING, |
1433 | Deny, | |
1434 | "usage of invalid atomic ordering in atomic operations and memory fences" | |
1435 | } | |
1436 | ||
1437 | declare_lint_pass!(InvalidAtomicOrdering => [INVALID_ATOMIC_ORDERING]); | |
1438 | ||
1439 | impl InvalidAtomicOrdering { | |
1440 | fn inherent_atomic_method_call<'hir>( | |
1441 | cx: &LateContext<'_>, | |
1442 | expr: &Expr<'hir>, | |
1443 | recognized_names: &[Symbol], // used for fast path calculation | |
1444 | ) -> Option<(Symbol, &'hir [Expr<'hir>])> { | |
1445 | const ATOMIC_TYPES: &[Symbol] = &[ | |
1446 | sym::AtomicBool, | |
1447 | sym::AtomicPtr, | |
1448 | sym::AtomicUsize, | |
1449 | sym::AtomicU8, | |
1450 | sym::AtomicU16, | |
1451 | sym::AtomicU32, | |
1452 | sym::AtomicU64, | |
1453 | sym::AtomicU128, | |
1454 | sym::AtomicIsize, | |
1455 | sym::AtomicI8, | |
1456 | sym::AtomicI16, | |
1457 | sym::AtomicI32, | |
1458 | sym::AtomicI64, | |
1459 | sym::AtomicI128, | |
1460 | ]; | |
f2b60f7d | 1461 | if let ExprKind::MethodCall(ref method_path, _, args, _) = &expr.kind |
5e7ed085 FG |
1462 | && recognized_names.contains(&method_path.ident.name) |
1463 | && let Some(m_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) | |
1464 | && let Some(impl_did) = cx.tcx.impl_of_method(m_def_id) | |
1465 | && let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() | |
94222f64 | 1466 | // skip extension traits, only lint functions from the standard library |
5e7ed085 | 1467 | && cx.tcx.trait_id_of_impl(impl_did).is_none() |
04454e1e | 1468 | && let parent = cx.tcx.parent(adt.did()) |
5e7ed085 FG |
1469 | && cx.tcx.is_diagnostic_item(sym::atomic_mod, parent) |
1470 | && ATOMIC_TYPES.contains(&cx.tcx.item_name(adt.did())) | |
1471 | { | |
1472 | return Some((method_path.ident.name, args)); | |
94222f64 XL |
1473 | } |
1474 | None | |
1475 | } | |
1476 | ||
064997fb FG |
1477 | fn match_ordering(cx: &LateContext<'_>, ord_arg: &Expr<'_>) -> Option<Symbol> { |
1478 | let ExprKind::Path(ref ord_qpath) = ord_arg.kind else { return None }; | |
1479 | let did = cx.qpath_res(ord_qpath, ord_arg.hir_id).opt_def_id()?; | |
94222f64 XL |
1480 | let tcx = cx.tcx; |
1481 | let atomic_ordering = tcx.get_diagnostic_item(sym::Ordering); | |
064997fb FG |
1482 | let name = tcx.item_name(did); |
1483 | let parent = tcx.parent(did); | |
1484 | [sym::Relaxed, sym::Release, sym::Acquire, sym::AcqRel, sym::SeqCst].into_iter().find( | |
1485 | |&ordering| { | |
1486 | name == ordering | |
1487 | && (Some(parent) == atomic_ordering | |
1488 | // needed in case this is a ctor, not a variant | |
1489 | || tcx.opt_parent(parent) == atomic_ordering) | |
1490 | }, | |
1491 | ) | |
94222f64 XL |
1492 | } |
1493 | ||
1494 | fn check_atomic_load_store(cx: &LateContext<'_>, expr: &Expr<'_>) { | |
5e7ed085 FG |
1495 | if let Some((method, args)) = Self::inherent_atomic_method_call(cx, expr, &[sym::load, sym::store]) |
1496 | && let Some((ordering_arg, invalid_ordering)) = match method { | |
f2b60f7d FG |
1497 | sym::load => Some((&args[0], sym::Release)), |
1498 | sym::store => Some((&args[1], sym::Acquire)), | |
94222f64 | 1499 | _ => None, |
94222f64 | 1500 | } |
064997fb FG |
1501 | && let Some(ordering) = Self::match_ordering(cx, ordering_arg) |
1502 | && (ordering == invalid_ordering || ordering == sym::AcqRel) | |
5e7ed085 FG |
1503 | { |
1504 | cx.struct_span_lint(INVALID_ATOMIC_ORDERING, ordering_arg.span, |diag| { | |
1505 | if method == sym::load { | |
064997fb FG |
1506 | diag.build(fluent::lint::atomic_ordering_load) |
1507 | .help(fluent::lint::help) | |
5e7ed085 FG |
1508 | .emit() |
1509 | } else { | |
1510 | debug_assert_eq!(method, sym::store); | |
064997fb FG |
1511 | diag.build(fluent::lint::atomic_ordering_store) |
1512 | .help(fluent::lint::help) | |
5e7ed085 FG |
1513 | .emit(); |
1514 | } | |
1515 | }); | |
94222f64 XL |
1516 | } |
1517 | } | |
1518 | ||
1519 | fn check_memory_fence(cx: &LateContext<'_>, expr: &Expr<'_>) { | |
5e7ed085 FG |
1520 | if let ExprKind::Call(ref func, ref args) = expr.kind |
1521 | && let ExprKind::Path(ref func_qpath) = func.kind | |
1522 | && let Some(def_id) = cx.qpath_res(func_qpath, func.hir_id).opt_def_id() | |
1523 | && matches!(cx.tcx.get_diagnostic_name(def_id), Some(sym::fence | sym::compiler_fence)) | |
064997fb | 1524 | && Self::match_ordering(cx, &args[0]) == Some(sym::Relaxed) |
5e7ed085 FG |
1525 | { |
1526 | cx.struct_span_lint(INVALID_ATOMIC_ORDERING, args[0].span, |diag| { | |
064997fb FG |
1527 | diag.build(fluent::lint::atomic_ordering_fence) |
1528 | .help(fluent::lint::help) | |
5e7ed085 FG |
1529 | .emit(); |
1530 | }); | |
94222f64 XL |
1531 | } |
1532 | } | |
1533 | ||
1534 | fn check_atomic_compare_exchange(cx: &LateContext<'_>, expr: &Expr<'_>) { | |
064997fb FG |
1535 | let Some((method, args)) = Self::inherent_atomic_method_call(cx, expr, &[sym::fetch_update, sym::compare_exchange, sym::compare_exchange_weak]) |
1536 | else {return }; | |
1537 | ||
1538 | let fail_order_arg = match method { | |
f2b60f7d FG |
1539 | sym::fetch_update => &args[1], |
1540 | sym::compare_exchange | sym::compare_exchange_weak => &args[3], | |
064997fb FG |
1541 | _ => return, |
1542 | }; | |
1543 | ||
1544 | let Some(fail_ordering) = Self::match_ordering(cx, fail_order_arg) else { return }; | |
1545 | ||
1546 | if matches!(fail_ordering, sym::Release | sym::AcqRel) { | |
1547 | #[derive(LintDiagnostic)] | |
f2b60f7d | 1548 | #[diag(lint::atomic_ordering_invalid)] |
064997fb FG |
1549 | #[help] |
1550 | struct InvalidAtomicOrderingDiag { | |
1551 | method: Symbol, | |
1552 | #[label] | |
1553 | fail_order_arg_span: Span, | |
94222f64 | 1554 | } |
064997fb FG |
1555 | |
1556 | cx.emit_spanned_lint( | |
1557 | INVALID_ATOMIC_ORDERING, | |
1558 | fail_order_arg.span, | |
1559 | InvalidAtomicOrderingDiag { method, fail_order_arg_span: fail_order_arg.span }, | |
1560 | ); | |
94222f64 XL |
1561 | } |
1562 | } | |
1563 | } | |
1564 | ||
1565 | impl<'tcx> LateLintPass<'tcx> for InvalidAtomicOrdering { | |
1566 | fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { | |
1567 | Self::check_atomic_load_store(cx, expr); | |
1568 | Self::check_memory_fence(cx, expr); | |
1569 | Self::check_atomic_compare_exchange(cx, expr); | |
1570 | } | |
1571 | } |