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::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         return (level, src)
 122     }
 123
 124     fn get_lint_id_level(&self,
 125                          id: LintId,
 126                          mut idx: u32,
 127                          aux: Option<&FxHashMap<LintId, (Level, LintSource)>>)
 128         -> (Option<Level>, LintSource)
 129     {
 130         if let Some(specs) = aux {
 131             if let Some(&(level, src)) = specs.get(&id) {
 132                 return (Some(level), src)
 133             }
 134         }
 135         loop {
 136             match self.list[idx as usize] {
 137                 LintSet::CommandLine { ref specs } => {
 138                     if let Some(&(level, src)) = specs.get(&id) {
 139                         return (Some(level), src)
 140                     }
 141                     return (None, LintSource::Default)
 142                 }
 143                 LintSet::Node { ref specs, parent } => {
 144                     if let Some(&(level, src)) = specs.get(&id) {
 145                         return (Some(level), src)
 146                     }
 147                     idx = parent;
 148                 }
 149             }
 150         }
 151     }
 152 }
 153
 154 pub struct LintLevelsBuilder<'a> {
 155     sess: &'a Session,
 156     sets: LintLevelSets,
 157     id_to_set: FxHashMap<HirId, u32>,
 158     cur: u32,
 159     warn_about_weird_lints: bool,
 160 }
 161
 162 pub struct BuilderPush {
 163     prev: u32,
 164 }
 165
 166 impl<'a> LintLevelsBuilder<'a> {
 167     pub fn new(sess: &'a Session, sets: LintLevelSets) -> LintLevelsBuilder<'a> {
 168         assert_eq!(sets.list.len(), 1);
 169         LintLevelsBuilder {
 170             sess,
 171             sets,
 172             cur: 0,
 173             id_to_set: FxHashMap(),
 174             warn_about_weird_lints: sess.buffered_lints.borrow().is_some(),
 175         }
 176     }
 177
 178     /// Pushes a list of AST lint attributes onto this context.
 179     ///
 180     /// This function will return a `BuilderPush` object which should be be
 181     /// passed to `pop` when this scope for the attributes provided is exited.
 182     ///
 183     /// This function will perform a number of tasks:
 184     ///
 185     /// * It'll validate all lint-related attributes in `attrs`
 186     /// * It'll mark all lint-related attriutes as used
 187     /// * Lint levels will be updated based on the attributes provided
 188     /// * Lint attributes are validated, e.g. a #[forbid] can't be switched to
 189     ///   #[allow]
 190     ///
 191     /// Don't forget to call `pop`!
 192     pub fn push(&mut self, attrs: &[ast::Attribute]) -> BuilderPush {
 193         let mut specs = FxHashMap();
 194         let store = self.sess.lint_store.borrow();
 195         let sess = self.sess;
 196         let bad_attr = |span| {
 197             span_err!(sess, span, E0452,
 198                       "malformed lint attribute");
 199         };
 200         for attr in attrs {
 201             let level = match attr.name().and_then(|name| Level::from_str(&name.as_str())) {
 202                 None => continue,
 203                 Some(lvl) => lvl,
 204             };
 205
 206             let meta = unwrap_or!(attr.meta(), continue);
 207             attr::mark_used(attr);
 208
 209             let metas = if let Some(metas) = meta.meta_item_list() {
 210                 metas
 211             } else {
 212                 bad_attr(meta.span);
 213                 continue
 214             };
 215
 216             for li in metas {
 217                 let word = match li.word() {
 218                     Some(word) => word,
 219                     None => {
 220                         bad_attr(li.span);
 221                         continue
 222                     }
 223                 };
 224                 let name = word.name();
 225                 match store.check_lint_name(&name.as_str()) {
 226                     CheckLintNameResult::Ok(ids) => {
 227                         let src = LintSource::Node(name, li.span);
 228                         for id in ids {
 229                             specs.insert(*id, (level, src));
 230                         }
 231                     }
 232
 233                     _ if !self.warn_about_weird_lints => {}
 234
 235                     CheckLintNameResult::Warning(ref msg) => {
 236                         let lint = builtin::RENAMED_AND_REMOVED_LINTS;
 237                         let (level, src) = self.sets.get_lint_level(lint,
 238                                                                     self.cur,
 239                                                                     Some(&specs),
 240                                                                     &sess);
 241                         lint::struct_lint_level(self.sess,
 242                                                 lint,
 243                                                 level,
 244                                                 src,
 245                                                 Some(li.span.into()),
 246                                                 msg)
 247                             .emit();
 248                     }
 249                     CheckLintNameResult::NoLint => {
 250                         let lint = builtin::UNKNOWN_LINTS;
 251                         let (level, src) = self.sets.get_lint_level(lint,
 252                                                                     self.cur,
 253                                                                     Some(&specs),
 254                                                                     self.sess);
 255                         let msg = format!("unknown lint: `{}`", name);
 256                         let mut db = lint::struct_lint_level(self.sess,
 257                                                 lint,
 258                                                 level,
 259                                                 src,
 260                                                 Some(li.span.into()),
 261                                                 &msg);
 262                         if name.as_str().chars().any(|c| c.is_uppercase()) {
 263                             let name_lower = name.as_str().to_lowercase();
 264                             if let CheckLintNameResult::NoLint =
 265                                     store.check_lint_name(&name_lower) {
 266                                 db.emit();
 267                             } else {
 268                                 db.span_suggestion(
 269                                     li.span,
 270                                     "lowercase the lint name",
 271                                     name_lower
 272                                 ).emit();
 273                             }
 274                         } else {
 275                             db.emit();
 276                         }
 277                     }
 278                 }
 279             }
 280         }
 281
 282         for (id, &(level, ref src)) in specs.iter() {
 283             if level == Level::Forbid {
 284                 continue
 285             }
 286             let forbid_src = match self.sets.get_lint_id_level(*id, self.cur, None) {
 287                 (Some(Level::Forbid), src) => src,
 288                 _ => continue,
 289             };
 290             let forbidden_lint_name = match forbid_src {
 291                 LintSource::Default => id.to_string(),
 292                 LintSource::Node(name, _) => name.to_string(),
 293                 LintSource::CommandLine(name) => name.to_string(),
 294             };
 295             let (lint_attr_name, lint_attr_span) = match *src {
 296                 LintSource::Node(name, span) => (name, span),
 297                 _ => continue,
 298             };
 299             let mut diag_builder = struct_span_err!(self.sess,
 300                                                     lint_attr_span,
 301                                                     E0453,
 302                                                     "{}({}) overruled by outer forbid({})",
 303                                                     level.as_str(),
 304                                                     lint_attr_name,
 305                                                     forbidden_lint_name);
 306             diag_builder.span_label(lint_attr_span, "overruled by previous forbid");
 307             match forbid_src {
 308                 LintSource::Default => &mut diag_builder,
 309                 LintSource::Node(_, forbid_source_span) => {
 310                     diag_builder.span_label(forbid_source_span,
 311                                             "`forbid` level set here")
 312                 },
 313                 LintSource::CommandLine(_) => {
 314                     diag_builder.note("`forbid` lint level was set on command line")
 315                 }
 316             }.emit();
 317             // don't set a separate error for every lint in the group
 318             break
 319         }
 320
 321         let prev = self.cur;
 322         if specs.len() > 0 {
 323             self.cur = self.sets.list.len() as u32;
 324             self.sets.list.push(LintSet::Node {
 325                 specs: specs,
 326                 parent: prev,
 327             });
 328         }
 329
 330         BuilderPush {
 331             prev: prev,
 332         }
 333     }
 334
 335     /// Called after `push` when the scope of a set of attributes are exited.
 336     pub fn pop(&mut self, push: BuilderPush) {
 337         self.cur = push.prev;
 338     }
 339
 340     /// Used to emit a lint-related diagnostic based on the current state of
 341     /// this lint context.
 342     pub fn struct_lint(&self,
 343                        lint: &'static Lint,
 344                        span: Option<MultiSpan>,
 345                        msg: &str)
 346         -> DiagnosticBuilder<'a>
 347     {
 348         let (level, src) = self.sets.get_lint_level(lint, self.cur, None, self.sess);
 349         lint::struct_lint_level(self.sess, lint, level, src, span, msg)
 350     }
 351
 352     /// Registers the ID provided with the current set of lints stored in
 353     /// this context.
 354     pub fn register_id(&mut self, id: HirId) {
 355         self.id_to_set.insert(id, self.cur);
 356     }
 357
 358     pub fn build(self) -> LintLevelSets {
 359         self.sets
 360     }
 361
 362     pub fn build_map(self) -> LintLevelMap {
 363         LintLevelMap {
 364             sets: self.sets,
 365             id_to_set: self.id_to_set,
 366         }
 367     }
 368 }
 369
 370 pub struct LintLevelMap {
 371     sets: LintLevelSets,
 372     id_to_set: FxHashMap<HirId, u32>,
 373 }
 374
 375 impl LintLevelMap {
 376     /// If the `id` was previously registered with `register_id` when building
 377     /// this `LintLevelMap` this returns the corresponding lint level and source
 378     /// of the lint level for the lint provided.
 379     ///
 380     /// If the `id` was not previously registered, returns `None`. If `None` is
 381     /// returned then the parent of `id` should be acquired and this function
 382     /// should be called again.
 383     pub fn level_and_source(&self, lint: &'static Lint, id: HirId, session: &Session)
 384         -> Option<(Level, LintSource)>
 385     {
 386         self.id_to_set.get(&id).map(|idx| {
 387             self.sets.get_lint_level(lint, *idx, None, session)
 388         })
 389     }
 390
 391     /// Returns if this `id` has lint level information.
 392     pub fn lint_level_set(&self, id: HirId) -> Option<u32> {
 393         self.id_to_set.get(&id).cloned()
 394     }
 395 }
 396
 397 impl<'a> HashStable<StableHashingContext<'a>> for LintLevelMap {
 398     #[inline]
 399     fn hash_stable<W: StableHasherResult>(&self,
 400                                           hcx: &mut StableHashingContext<'a>,
 401                                           hasher: &mut StableHasher<W>) {
 402         let LintLevelMap {
 403             ref sets,
 404             ref id_to_set,
 405         } = *self;
 406
 407         id_to_set.hash_stable(hcx, hasher);
 408
 409         let LintLevelSets {
 410             ref list,
 411             lint_cap,
 412         } = *sets;
 413
 414         lint_cap.hash_stable(hcx, hasher);
 415
 416         hcx.while_hashing_spans(true, |hcx| {
 417             list.len().hash_stable(hcx, hasher);
 418
 419             // We are working under the assumption here that the list of
 420             // lint-sets is built in a deterministic order.
 421             for lint_set in list {
 422                 ::std::mem::discriminant(lint_set).hash_stable(hcx, hasher);
 423
 424                 match *lint_set {
 425                     LintSet::CommandLine { ref specs } => {
 426                         specs.hash_stable(hcx, hasher);
 427                     }
 428                     LintSet::Node { ref specs, parent } => {
 429                         specs.hash_stable(hcx, hasher);
 430                         parent.hash_stable(hcx, hasher);
 431                     }
 432                 }
 433             }
 434         })
 435     }
 436 }
 437
 438 impl<HCX> HashStable<HCX> for LintId {
 439     #[inline]
 440     fn hash_stable<W: StableHasherResult>(&self,
 441                                           hcx: &mut HCX,
 442                                           hasher: &mut StableHasher<W>) {
 443         self.lint_name_raw().hash_stable(hcx, hasher);
 444     }
 445 }
 446
 447 impl<HCX> ToStableHashKey<HCX> for LintId {
 448     type KeyType = &'static str;
 449
 450     #[inline]
 451     fn to_stable_hash_key(&self, _: &HCX) -> &'static str {
 452         self.lint_name_raw()
 453     }
 454 }