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