src/librustc/lint/levels.rs

   1 // Copyright 2017 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use std::cmp;
  12
  13 use errors::{Applicability, DiagnosticBuilder};
  14 use hir::HirId;
  15 use ich::StableHashingContext;
  16 use lint::builtin;
  17 use lint::context::CheckLintNameResult;
  18 use lint::{self, Lint, LintId, Level, LintSource};
  19 use rustc_data_structures::stable_hasher::{HashStable, ToStableHashKey,
  20                                            StableHasher, StableHasherResult};
  21 use session::Session;
  22 use syntax::ast;
  23 use syntax::attr;
  24 use syntax::codemap::MultiSpan;
  25 use syntax::symbol::Symbol;
  26 use util::nodemap::FxHashMap;
  27
  28 pub struct LintLevelSets {
  29     list: Vec<LintSet>,
  30     lint_cap: Level,
  31 }
  32
  33 enum LintSet {
  34     CommandLine {
  35         // -A,-W,-D flags, a `Symbol` for the flag itself and `Level` for which
  36         // flag.
  37         specs: FxHashMap<LintId, (Level, LintSource)>,
  38     },
  39
  40     Node {
  41         specs: FxHashMap<LintId, (Level, LintSource)>,
  42         parent: u32,
  43     },
  44 }
  45
  46 impl LintLevelSets {
  47     pub fn new(sess: &Session) -> LintLevelSets {
  48         let mut me = LintLevelSets {
  49             list: Vec::new(),
  50             lint_cap: Level::Forbid,
  51         };
  52         me.process_command_line(sess);
  53         return me
  54     }
  55
  56     pub fn builder(sess: &Session) -> LintLevelsBuilder {
  57         LintLevelsBuilder::new(sess, LintLevelSets::new(sess))
  58     }
  59
  60     fn process_command_line(&mut self, sess: &Session) {
  61         let store = sess.lint_store.borrow();
  62         let mut specs = FxHashMap();
  63         self.lint_cap = sess.opts.lint_cap.unwrap_or(Level::Forbid);
  64
  65         for &(ref lint_name, level) in &sess.opts.lint_opts {
  66             store.check_lint_name_cmdline(sess, &lint_name, level);
  67
  68             // If the cap is less than this specified level, e.g. if we've got
  69             // `--cap-lints allow` but we've also got `-D foo` then we ignore
  70             // this specification as the lint cap will set it to allow anyway.
  71             let level = cmp::min(level, self.lint_cap);
  72
  73             let lint_flag_val = Symbol::intern(lint_name);
  74             let ids = match store.find_lints(&lint_name) {
  75                 Ok(ids) => ids,
  76                 Err(_) => continue, // errors handled in check_lint_name_cmdline above
  77             };
  78             for id in ids {
  79                 let src = LintSource::CommandLine(lint_flag_val);
  80                 specs.insert(id, (level, src));
  81             }
  82         }
  83
  84         self.list.push(LintSet::CommandLine {
  85             specs: specs,
  86         });
  87     }
  88
  89     fn get_lint_level(&self,
  90                       lint: &'static Lint,
  91                       idx: u32,
  92                       aux: Option<&FxHashMap<LintId, (Level, LintSource)>>,
  93                       sess: &Session)
  94         -> (Level, LintSource)
  95     {
  96         let (level, mut src) = self.get_lint_id_level(LintId::of(lint), idx, aux);
  97
  98         // If `level` is none then we actually assume the default level for this
  99         // lint.
 100         let mut level = level.unwrap_or(lint.default_level(sess));
 101
 102         // If we're about to issue a warning, check at the last minute for any
 103         // directives against the warnings "lint". If, for example, there's an
 104         // `allow(warnings)` in scope then we want to respect that instead.
 105         if level == Level::Warn {
 106             let (warnings_level, warnings_src) =
 107                 self.get_lint_id_level(LintId::of(lint::builtin::WARNINGS),
 108                                        idx,
 109                                        aux);
 110             if let Some(configured_warning_level) = warnings_level {
 111                 if configured_warning_level != Level::Warn {
 112                     level = configured_warning_level;
 113                     src = warnings_src;
 114                 }
 115             }
 116         }
 117
 118         // Ensure that we never exceed the `--cap-lints` argument.
 119         level = cmp::min(level, self.lint_cap);
 120
 121         if let Some(driver_level) = sess.driver_lint_caps.get(&LintId::of(lint)) {
 122             // Ensure that we never exceed driver level.
 123             level = cmp::min(*driver_level, level);
 124         }
 125
 126         return (level, src)
 127     }
 128
 129     fn get_lint_id_level(&self,
 130                          id: LintId,
 131                          mut idx: u32,
 132                          aux: Option<&FxHashMap<LintId, (Level, LintSource)>>)
 133         -> (Option<Level>, LintSource)
 134     {
 135         if let Some(specs) = aux {
 136             if let Some(&(level, src)) = specs.get(&id) {
 137                 return (Some(level), src)
 138             }
 139         }
 140         loop {
 141             match self.list[idx as usize] {
 142                 LintSet::CommandLine { ref specs } => {
 143                     if let Some(&(level, src)) = specs.get(&id) {
 144                         return (Some(level), src)
 145                     }
 146                     return (None, LintSource::Default)
 147                 }
 148                 LintSet::Node { ref specs, parent } => {
 149                     if let Some(&(level, src)) = specs.get(&id) {
 150                         return (Some(level), src)
 151                     }
 152                     idx = parent;
 153                 }
 154             }
 155         }
 156     }
 157 }
 158
 159 pub struct LintLevelsBuilder<'a> {
 160     sess: &'a Session,
 161     sets: LintLevelSets,
 162     id_to_set: FxHashMap<HirId, u32>,
 163     cur: u32,
 164     warn_about_weird_lints: bool,
 165 }
 166
 167 pub struct BuilderPush {
 168     prev: u32,
 169 }
 170
 171 impl<'a> LintLevelsBuilder<'a> {
 172     pub fn new(sess: &'a Session, sets: LintLevelSets) -> LintLevelsBuilder<'a> {
 173         assert_eq!(sets.list.len(), 1);
 174         LintLevelsBuilder {
 175             sess,
 176             sets,
 177             cur: 0,
 178             id_to_set: FxHashMap(),
 179             warn_about_weird_lints: sess.buffered_lints.borrow().is_some(),
 180         }
 181     }
 182
 183     /// Pushes a list of AST lint attributes onto this context.
 184     ///
 185     /// This function will return a `BuilderPush` object which should be be
 186     /// passed to `pop` when this scope for the attributes provided is exited.
 187     ///
 188     /// This function will perform a number of tasks:
 189     ///
 190     /// * It'll validate all lint-related attributes in `attrs`
 191     /// * It'll mark all lint-related attriutes as used
 192     /// * Lint levels will be updated based on the attributes provided
 193     /// * Lint attributes are validated, e.g. a #[forbid] can't be switched to
 194     ///   #[allow]
 195     ///
 196     /// Don't forget to call `pop`!
 197     pub fn push(&mut self, attrs: &[ast::Attribute]) -> BuilderPush {
 198         let mut specs = FxHashMap();
 199         let store = self.sess.lint_store.borrow();
 200         let sess = self.sess;
 201         let bad_attr = |span| {
 202             span_err!(sess, span, E0452,
 203                       "malformed lint attribute");
 204         };
 205         for attr in attrs {
 206             let level = match Level::from_str(&attr.name().as_str()) {
 207                 None => continue,
 208                 Some(lvl) => lvl,
 209             };
 210
 211             let meta = unwrap_or!(attr.meta(), continue);
 212             attr::mark_used(attr);
 213
 214             let metas = if let Some(metas) = meta.meta_item_list() {
 215                 metas
 216             } else {
 217                 bad_attr(meta.span);
 218                 continue
 219             };
 220
 221             for li in metas {
 222                 let word = match li.word() {
 223                     Some(word) => word,
 224                     None => {
 225                         bad_attr(li.span);
 226                         continue
 227                     }
 228                 };
 229                 let name = word.name();
 230                 match store.check_lint_name(&name.as_str()) {
 231                     CheckLintNameResult::Ok(ids) => {
 232                         let src = LintSource::Node(name, li.span);
 233                         for id in ids {
 234                             specs.insert(*id, (level, src));
 235                         }
 236                     }
 237
 238                     _ if !self.warn_about_weird_lints => {}
 239
 240                     CheckLintNameResult::Warning(ref msg) => {
 241                         let lint = builtin::RENAMED_AND_REMOVED_LINTS;
 242                         let (level, src) = self.sets.get_lint_level(lint,
 243                                                                     self.cur,
 244                                                                     Some(&specs),
 245                                                                     &sess);
 246                         lint::struct_lint_level(self.sess,
 247                                                 lint,
 248                                                 level,
 249                                                 src,
 250                                                 Some(li.span.into()),
 251                                                 msg)
 252                             .emit();
 253                     }
 254                     CheckLintNameResult::NoLint => {
 255                         let lint = builtin::UNKNOWN_LINTS;
 256                         let (level, src) = self.sets.get_lint_level(lint,
 257                                                                     self.cur,
 258                                                                     Some(&specs),
 259                                                                     self.sess);
 260                         let msg = format!("unknown lint: `{}`", name);
 261                         let mut db = lint::struct_lint_level(self.sess,
 262                                                 lint,
 263                                                 level,
 264                                                 src,
 265                                                 Some(li.span.into()),
 266                                                 &msg);
 267                         if name.as_str().chars().any(|c| c.is_uppercase()) {
 268                             let name_lower = name.as_str().to_lowercase().to_string();
 269                             if let CheckLintNameResult::NoLint =
 270                                     store.check_lint_name(&name_lower) {
 271                                 db.emit();
 272                             } else {
 273                                 db.span_suggestion_with_applicability(
 274                                     li.span,
 275                                     "lowercase the lint name",
 276                                     name_lower,
 277                                     Applicability::MachineApplicable
 278                                 ).emit();
 279                             }
 280                         } else {
 281                             db.emit();
 282                         }
 283                     }
 284                 }
 285             }
 286         }
 287
 288         for (id, &(level, ref src)) in specs.iter() {
 289             if level == Level::Forbid {
 290                 continue
 291             }
 292             let forbid_src = match self.sets.get_lint_id_level(*id, self.cur, None) {
 293                 (Some(Level::Forbid), src) => src,
 294                 _ => continue,
 295             };
 296             let forbidden_lint_name = match forbid_src {
 297                 LintSource::Default => id.to_string(),
 298                 LintSource::Node(name, _) => name.to_string(),
 299                 LintSource::CommandLine(name) => name.to_string(),
 300             };
 301             let (lint_attr_name, lint_attr_span) = match *src {
 302                 LintSource::Node(name, span) => (name, span),
 303                 _ => continue,
 304             };
 305             let mut diag_builder = struct_span_err!(self.sess,
 306                                                     lint_attr_span,
 307                                                     E0453,
 308                                                     "{}({}) overruled by outer forbid({})",
 309                                                     level.as_str(),
 310                                                     lint_attr_name,
 311                                                     forbidden_lint_name);
 312             diag_builder.span_label(lint_attr_span, "overruled by previous forbid");
 313             match forbid_src {
 314                 LintSource::Default => &mut diag_builder,
 315                 LintSource::Node(_, forbid_source_span) => {
 316                     diag_builder.span_label(forbid_source_span,
 317                                             "`forbid` level set here")
 318                 },
 319                 LintSource::CommandLine(_) => {
 320                     diag_builder.note("`forbid` lint level was set on command line")
 321                 }
 322             }.emit();
 323             // don't set a separate error for every lint in the group
 324             break
 325         }
 326
 327         let prev = self.cur;
 328         if specs.len() > 0 {
 329             self.cur = self.sets.list.len() as u32;
 330             self.sets.list.push(LintSet::Node {
 331                 specs: specs,
 332                 parent: prev,
 333             });
 334         }
 335
 336         BuilderPush {
 337             prev: prev,
 338         }
 339     }
 340
 341     /// Called after `push` when the scope of a set of attributes are exited.
 342     pub fn pop(&mut self, push: BuilderPush) {
 343         self.cur = push.prev;
 344     }
 345
 346     /// Used to emit a lint-related diagnostic based on the current state of
 347     /// this lint context.
 348     pub fn struct_lint(&self,
 349                        lint: &'static Lint,
 350                        span: Option<MultiSpan>,
 351                        msg: &str)
 352         -> DiagnosticBuilder<'a>
 353     {
 354         let (level, src) = self.sets.get_lint_level(lint, self.cur, None, self.sess);
 355         lint::struct_lint_level(self.sess, lint, level, src, span, msg)
 356     }
 357
 358     /// Registers the ID provided with the current set of lints stored in
 359     /// this context.
 360     pub fn register_id(&mut self, id: HirId) {
 361         self.id_to_set.insert(id, self.cur);
 362     }
 363
 364     pub fn build(self) -> LintLevelSets {
 365         self.sets
 366     }
 367
 368     pub fn build_map(self) -> LintLevelMap {
 369         LintLevelMap {
 370             sets: self.sets,
 371             id_to_set: self.id_to_set,
 372         }
 373     }
 374 }
 375
 376 pub struct LintLevelMap {
 377     sets: LintLevelSets,
 378     id_to_set: FxHashMap<HirId, u32>,
 379 }
 380
 381 impl LintLevelMap {
 382     /// If the `id` was previously registered with `register_id` when building
 383     /// this `LintLevelMap` this returns the corresponding lint level and source
 384     /// of the lint level for the lint provided.
 385     ///
 386     /// If the `id` was not previously registered, returns `None`. If `None` is
 387     /// returned then the parent of `id` should be acquired and this function
 388     /// should be called again.
 389     pub fn level_and_source(&self, lint: &'static Lint, id: HirId, session: &Session)
 390         -> Option<(Level, LintSource)>
 391     {
 392         self.id_to_set.get(&id).map(|idx| {
 393             self.sets.get_lint_level(lint, *idx, None, session)
 394         })
 395     }
 396
 397     /// Returns if this `id` has lint level information.
 398     pub fn lint_level_set(&self, id: HirId) -> Option<u32> {
 399         self.id_to_set.get(&id).cloned()
 400     }
 401 }
 402
 403 impl<'a> HashStable<StableHashingContext<'a>> for LintLevelMap {
 404     #[inline]
 405     fn hash_stable<W: StableHasherResult>(&self,
 406                                           hcx: &mut StableHashingContext<'a>,
 407                                           hasher: &mut StableHasher<W>) {
 408         let LintLevelMap {
 409             ref sets,
 410             ref id_to_set,
 411         } = *self;
 412
 413         id_to_set.hash_stable(hcx, hasher);
 414
 415         let LintLevelSets {
 416             ref list,
 417             lint_cap,
 418         } = *sets;
 419
 420         lint_cap.hash_stable(hcx, hasher);
 421
 422         hcx.while_hashing_spans(true, |hcx| {
 423             list.len().hash_stable(hcx, hasher);
 424
 425             // We are working under the assumption here that the list of
 426             // lint-sets is built in a deterministic order.
 427             for lint_set in list {
 428                 ::std::mem::discriminant(lint_set).hash_stable(hcx, hasher);
 429
 430                 match *lint_set {
 431                     LintSet::CommandLine { ref specs } => {
 432                         specs.hash_stable(hcx, hasher);
 433                     }
 434                     LintSet::Node { ref specs, parent } => {
 435                         specs.hash_stable(hcx, hasher);
 436                         parent.hash_stable(hcx, hasher);
 437                     }
 438                 }
 439             }
 440         })
 441     }
 442 }
 443
 444 impl<HCX> HashStable<HCX> for LintId {
 445     #[inline]
 446     fn hash_stable<W: StableHasherResult>(&self,
 447                                           hcx: &mut HCX,
 448                                           hasher: &mut StableHasher<W>) {
 449         self.lint_name_raw().hash_stable(hcx, hasher);
 450     }
 451 }
 452
 453 impl<HCX> ToStableHashKey<HCX> for LintId {
 454     type KeyType = &'static str;
 455
 456     #[inline]
 457     fn to_stable_hash_key(&self, _: &HCX) -> &'static str {
 458         self.lint_name_raw()
 459     }
 460 }