src/librustc/ty/maps/plumbing.rs

   1 // Copyright 2012-2015 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 //! The implementation of the query system itself. Defines the macros
  12 //! that generate the actual methods on tcx which find and execute the
  13 //! provider, manage the caches, and so forth.
  14
  15 use dep_graph::{DepNodeIndex, DepNode, DepKind, DepNodeColor};
  16 use errors::DiagnosticBuilder;
  17 use ty::{TyCtxt};
  18 use ty::maps::Query; // NB: actually generated by the macros in this file
  19 use ty::maps::config::QueryDescription;
  20 use ty::item_path;
  21
  22 use rustc_data_structures::fx::{FxHashMap};
  23 use std::cell::RefMut;
  24 use std::marker::PhantomData;
  25 use std::mem;
  26 use syntax_pos::Span;
  27
  28 pub(super) struct QueryMap<D: QueryDescription> {
  29     phantom: PhantomData<D>,
  30     pub(super) map: FxHashMap<D::Key, QueryValue<D::Value>>,
  31 }
  32
  33 pub(super) struct QueryValue<T> {
  34     pub(super) value: T,
  35     pub(super) index: DepNodeIndex,
  36 }
  37
  38 impl<T> QueryValue<T> {
  39     pub(super) fn new(value: T,
  40                       dep_node_index: DepNodeIndex)
  41                       -> QueryValue<T> {
  42         QueryValue {
  43             value,
  44             index: dep_node_index,
  45         }
  46     }
  47 }
  48
  49 impl<M: QueryDescription> QueryMap<M> {
  50     pub(super) fn new() -> QueryMap<M> {
  51         QueryMap {
  52             phantom: PhantomData,
  53             map: FxHashMap(),
  54         }
  55     }
  56 }
  57
  58 pub(super) struct CycleError<'a, 'tcx: 'a> {
  59     span: Span,
  60     cycle: RefMut<'a, [(Span, Query<'tcx>)]>,
  61 }
  62
  63 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
  64     pub(super) fn report_cycle(self, CycleError { span, cycle }: CycleError)
  65         -> DiagnosticBuilder<'a>
  66     {
  67         // Subtle: release the refcell lock before invoking `describe()`
  68         // below by dropping `cycle`.
  69         let stack = cycle.to_vec();
  70         mem::drop(cycle);
  71
  72         assert!(!stack.is_empty());
  73
  74         // Disable naming impls with types in this path, since that
  75         // sometimes cycles itself, leading to extra cycle errors.
  76         // (And cycle errors around impls tend to occur during the
  77         // collect/coherence phases anyhow.)
  78         item_path::with_forced_impl_filename_line(|| {
  79             let mut err =
  80                 struct_span_err!(self.sess, span, E0391,
  81                                  "unsupported cyclic reference between types/traits detected");
  82             err.span_label(span, "cyclic reference");
  83
  84             err.span_note(stack[0].0, &format!("the cycle begins when {}...",
  85                                                stack[0].1.describe(self)));
  86
  87             for &(span, ref query) in &stack[1..] {
  88                 err.span_note(span, &format!("...which then requires {}...",
  89                                              query.describe(self)));
  90             }
  91
  92             err.note(&format!("...which then again requires {}, completing the cycle.",
  93                               stack[0].1.describe(self)));
  94
  95             return err
  96         })
  97     }
  98
  99     pub(super) fn cycle_check<F, R>(self, span: Span, query: Query<'gcx>, compute: F)
 100                                     -> Result<R, CycleError<'a, 'gcx>>
 101         where F: FnOnce() -> R
 102     {
 103         {
 104             let mut stack = self.maps.query_stack.borrow_mut();
 105             if let Some((i, _)) = stack.iter().enumerate().rev()
 106                                        .find(|&(_, &(_, ref q))| *q == query) {
 107                 return Err(CycleError {
 108                     span,
 109                     cycle: RefMut::map(stack, |stack| &mut stack[i..])
 110                 });
 111             }
 112             stack.push((span, query));
 113         }
 114
 115         let result = compute();
 116
 117         self.maps.query_stack.borrow_mut().pop();
 118
 119         Ok(result)
 120     }
 121
 122     /// Try to read a node index for the node dep_node.
 123     /// A node will have an index, when it's already been marked green, or when we can mark it
 124     /// green. This function will mark the current task as a reader of the specified node, when
 125     /// the a node index can be found for that node.
 126     pub(super) fn try_mark_green_and_read(self, dep_node: &DepNode) -> Option<DepNodeIndex> {
 127         match self.dep_graph.node_color(dep_node) {
 128             Some(DepNodeColor::Green(dep_node_index)) => {
 129                 self.dep_graph.read_index(dep_node_index);
 130                 Some(dep_node_index)
 131             }
 132             Some(DepNodeColor::Red) => {
 133                 None
 134             }
 135             None => {
 136                 // try_mark_green (called below) will panic when full incremental
 137                 // compilation is disabled. If that's the case, we can't try to mark nodes
 138                 // as green anyway, so we can safely return None here.
 139                 if !self.dep_graph.is_fully_enabled() {
 140                     return None;
 141                 }
 142                 match self.dep_graph.try_mark_green(self, &dep_node) {
 143                     Some(dep_node_index) => {
 144                         debug_assert!(self.dep_graph.is_green(dep_node_index));
 145                         self.dep_graph.read_index(dep_node_index);
 146                         Some(dep_node_index)
 147                     }
 148                     None => {
 149                         None
 150                     }
 151                 }
 152             }
 153         }
 154     }
 155 }
 156
 157 // If enabled, send a message to the profile-queries thread
 158 macro_rules! profq_msg {
 159     ($tcx:expr, $msg:expr) => {
 160         if cfg!(debug_assertions) {
 161             if  $tcx.sess.profile_queries() {
 162                 profq_msg($msg)
 163             }
 164         }
 165     }
 166 }
 167
 168 // If enabled, format a key using its debug string, which can be
 169 // expensive to compute (in terms of time).
 170 macro_rules! profq_key {
 171     ($tcx:expr, $key:expr) => {
 172         if cfg!(debug_assertions) {
 173             if $tcx.sess.profile_queries_and_keys() {
 174                 Some(format!("{:?}", $key))
 175             } else { None }
 176         } else { None }
 177     }
 178 }
 179
 180 macro_rules! define_maps {
 181     (<$tcx:tt>
 182      $($(#[$attr:meta])*
 183        [$($modifiers:tt)*] fn $name:ident: $node:ident($K:ty) -> $V:ty,)*) => {
 184
 185         use dep_graph::DepNodeIndex;
 186         use std::cell::RefCell;
 187
 188         define_map_struct! {
 189             tcx: $tcx,
 190             input: ($(([$($modifiers)*] [$($attr)*] [$name]))*)
 191         }
 192
 193         impl<$tcx> Maps<$tcx> {
 194             pub fn new(providers: IndexVec<CrateNum, Providers<$tcx>>)
 195                        -> Self {
 196                 Maps {
 197                     providers,
 198                     query_stack: RefCell::new(vec![]),
 199                     $($name: RefCell::new(QueryMap::new())),*
 200                 }
 201             }
 202         }
 203
 204         #[allow(bad_style)]
 205         #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 206         pub enum Query<$tcx> {
 207             $($(#[$attr])* $name($K)),*
 208         }
 209
 210         #[allow(bad_style)]
 211         #[derive(Clone, Debug, PartialEq, Eq)]
 212         pub enum QueryMsg {
 213             $($name(Option<String>)),*
 214         }
 215
 216         impl<$tcx> Query<$tcx> {
 217             pub fn describe(&self, tcx: TyCtxt) -> String {
 218                 let (r, name) = match *self {
 219                     $(Query::$name(key) => {
 220                         (queries::$name::describe(tcx, key), stringify!($name))
 221                     })*
 222                 };
 223                 if tcx.sess.verbose() {
 224                     format!("{} [{}]", r, name)
 225                 } else {
 226                     r
 227                 }
 228             }
 229         }
 230
 231         pub mod queries {
 232             use std::marker::PhantomData;
 233
 234             $(#[allow(bad_style)]
 235             pub struct $name<$tcx> {
 236                 data: PhantomData<&$tcx ()>
 237             })*
 238         }
 239
 240         $(impl<$tcx> QueryConfig for queries::$name<$tcx> {
 241             type Key = $K;
 242             type Value = $V;
 243         }
 244
 245         impl<'a, $tcx, 'lcx> queries::$name<$tcx> {
 246
 247             #[allow(unused)]
 248             fn to_dep_node(tcx: TyCtxt<'a, $tcx, 'lcx>, key: &$K) -> DepNode {
 249                 use dep_graph::DepConstructor::*;
 250
 251                 DepNode::new(tcx, $node(*key))
 252             }
 253
 254             fn try_get_with(tcx: TyCtxt<'a, $tcx, 'lcx>,
 255                             mut span: Span,
 256                             key: $K)
 257                             -> Result<$V, CycleError<'a, $tcx>>
 258             {
 259                 debug!("ty::queries::{}::try_get_with(key={:?}, span={:?})",
 260                        stringify!($name),
 261                        key,
 262                        span);
 263
 264                 profq_msg!(tcx,
 265                     ProfileQueriesMsg::QueryBegin(
 266                         span.data(),
 267                         QueryMsg::$name(profq_key!(tcx, key))
 268                     )
 269                 );
 270
 271                 if let Some(value) = tcx.maps.$name.borrow().map.get(&key) {
 272                     profq_msg!(tcx, ProfileQueriesMsg::CacheHit);
 273                     tcx.dep_graph.read_index(value.index);
 274                     return Ok((&value.value).clone());
 275                 }
 276
 277                 // FIXME(eddyb) Get more valid Span's on queries.
 278                 // def_span guard is necessary to prevent a recursive loop,
 279                 // default_span calls def_span query internally.
 280                 if span == DUMMY_SP && stringify!($name) != "def_span" {
 281                     span = key.default_span(tcx)
 282                 }
 283
 284                 // Fast path for when incr. comp. is off. `to_dep_node` is
 285                 // expensive for some DepKinds.
 286                 if !tcx.dep_graph.is_fully_enabled() {
 287                     let null_dep_node = DepNode::new_no_params(::dep_graph::DepKind::Null);
 288                     return Self::force(tcx, key, span, null_dep_node)
 289                                 .map(|(v, _)| v);
 290                 }
 291
 292                 let dep_node = Self::to_dep_node(tcx, &key);
 293
 294                 if dep_node.kind.is_anon() {
 295                     profq_msg!(tcx, ProfileQueriesMsg::ProviderBegin);
 296
 297                     let res = tcx.cycle_check(span, Query::$name(key), || {
 298                         tcx.sess.diagnostic().track_diagnostics(|| {
 299                             tcx.dep_graph.with_anon_task(dep_node.kind, || {
 300                                 Self::compute_result(tcx.global_tcx(), key)
 301                             })
 302                         })
 303                     })?;
 304
 305                     profq_msg!(tcx, ProfileQueriesMsg::ProviderEnd);
 306                     let ((result, dep_node_index), diagnostics) = res;
 307
 308                     tcx.dep_graph.read_index(dep_node_index);
 309
 310                     tcx.on_disk_query_result_cache
 311                        .store_diagnostics_for_anon_node(dep_node_index, diagnostics);
 312
 313                     let value = QueryValue::new(result, dep_node_index);
 314
 315                     return Ok((&tcx.maps
 316                                     .$name
 317                                     .borrow_mut()
 318                                     .map
 319                                     .entry(key)
 320                                     .or_insert(value)
 321                                     .value).clone());
 322                 }
 323
 324                 if !dep_node.kind.is_input() {
 325                     if let Some(dep_node_index) = tcx.try_mark_green_and_read(&dep_node) {
 326                         profq_msg!(tcx, ProfileQueriesMsg::CacheHit);
 327                         return Self::load_from_disk_and_cache_in_memory(tcx,
 328                                                                         key,
 329                                                                         span,
 330                                                                         dep_node_index,
 331                                                                         &dep_node)
 332                     }
 333                 }
 334
 335                 match Self::force(tcx, key, span, dep_node) {
 336                     Ok((result, dep_node_index)) => {
 337                         tcx.dep_graph.read_index(dep_node_index);
 338                         Ok(result)
 339                     }
 340                     Err(e) => Err(e)
 341                 }
 342             }
 343
 344             /// Ensure that either this query has all green inputs or been executed.
 345             /// Executing query::ensure(D) is considered a read of the dep-node D.
 346             ///
 347             /// This function is particularly useful when executing passes for their
 348             /// side-effects -- e.g., in order to report errors for erroneous programs.
 349             ///
 350             /// Note: The optimization is only available during incr. comp.
 351             pub fn ensure(tcx: TyCtxt<'a, $tcx, 'lcx>, key: $K) -> () {
 352                 let dep_node = Self::to_dep_node(tcx, &key);
 353
 354                 // Ensuring an "input" or anonymous query makes no sense
 355                 assert!(!dep_node.kind.is_anon());
 356                 assert!(!dep_node.kind.is_input());
 357                 if tcx.try_mark_green_and_read(&dep_node).is_none() {
 358                     // A None return from `try_mark_green_and_read` means that this is either
 359                     // a new dep node or that the dep node has already been marked red.
 360                     // Either way, we can't call `dep_graph.read()` as we don't have the
 361                     // DepNodeIndex. We must invoke the query itself. The performance cost
 362                     // this introduces should be negligible as we'll immediately hit the
 363                     // in-memory cache, or another query down the line will.
 364                     let _ = tcx.$name(key);
 365                 }
 366             }
 367
 368             fn compute_result(tcx: TyCtxt<'a, $tcx, 'lcx>, key: $K) -> $V {
 369                 let provider = tcx.maps.providers[key.map_crate()].$name;
 370                 provider(tcx.global_tcx(), key)
 371             }
 372
 373             fn load_from_disk_and_cache_in_memory(tcx: TyCtxt<'a, $tcx, 'lcx>,
 374                                                   key: $K,
 375                                                   span: Span,
 376                                                   dep_node_index: DepNodeIndex,
 377                                                   dep_node: &DepNode)
 378                                                   -> Result<$V, CycleError<'a, $tcx>>
 379             {
 380                 debug_assert!(tcx.dep_graph.is_green(dep_node_index));
 381
 382                 // We don't do any caching yet, so recompute.
 383                 // The diagnostics for this query have already been promoted to
 384                 // the current session during try_mark_green(), so we can ignore
 385                 // them here.
 386                 let (result, _) = tcx.cycle_check(span, Query::$name(key), || {
 387                     tcx.sess.diagnostic().track_diagnostics(|| {
 388                         // The dep-graph for this computation is already in place
 389                         tcx.dep_graph.with_ignore(|| {
 390                             Self::compute_result(tcx, key)
 391                         })
 392                     })
 393                 })?;
 394
 395                 // If -Zincremental-verify-ich is specified, re-hash results from
 396                 // the cache and make sure that they have the expected fingerprint.
 397                 if tcx.sess.opts.debugging_opts.incremental_verify_ich {
 398                     use rustc_data_structures::stable_hasher::{StableHasher, HashStable};
 399                     use ich::Fingerprint;
 400
 401                     assert!(Some(tcx.dep_graph.fingerprint_of(dep_node)) ==
 402                             tcx.dep_graph.prev_fingerprint_of(dep_node),
 403                             "Fingerprint for green query instance not loaded \
 404                              from cache: {:?}", dep_node);
 405
 406                     debug!("BEGIN verify_ich({:?})", dep_node);
 407                     let mut hcx = tcx.create_stable_hashing_context();
 408                     let mut hasher = StableHasher::new();
 409
 410                     result.hash_stable(&mut hcx, &mut hasher);
 411
 412                     let new_hash: Fingerprint = hasher.finish();
 413                     debug!("END verify_ich({:?})", dep_node);
 414
 415                     let old_hash = tcx.dep_graph.fingerprint_of(dep_node);
 416
 417                     assert!(new_hash == old_hash, "Found unstable fingerprints \
 418                         for {:?}", dep_node);
 419                 }
 420
 421                 if tcx.sess.opts.debugging_opts.query_dep_graph {
 422                     tcx.dep_graph.mark_loaded_from_cache(dep_node_index, true);
 423                 }
 424
 425                 let value = QueryValue::new(result, dep_node_index);
 426
 427                 Ok((&tcx.maps
 428                          .$name
 429                          .borrow_mut()
 430                          .map
 431                          .entry(key)
 432                          .or_insert(value)
 433                          .value).clone())
 434             }
 435
 436             fn force(tcx: TyCtxt<'a, $tcx, 'lcx>,
 437                      key: $K,
 438                      span: Span,
 439                      dep_node: DepNode)
 440                      -> Result<($V, DepNodeIndex), CycleError<'a, $tcx>> {
 441                 debug_assert!(tcx.dep_graph.node_color(&dep_node).is_none());
 442
 443                 profq_msg!(tcx, ProfileQueriesMsg::ProviderBegin);
 444                 let res = tcx.cycle_check(span, Query::$name(key), || {
 445                     tcx.sess.diagnostic().track_diagnostics(|| {
 446                         if dep_node.kind.is_eval_always() {
 447                             tcx.dep_graph.with_eval_always_task(dep_node,
 448                                                                 tcx,
 449                                                                 key,
 450                                                                 Self::compute_result)
 451                         } else {
 452                             tcx.dep_graph.with_task(dep_node,
 453                                                     tcx,
 454                                                     key,
 455                                                     Self::compute_result)
 456                         }
 457                     })
 458                 })?;
 459                 profq_msg!(tcx, ProfileQueriesMsg::ProviderEnd);
 460
 461                 let ((result, dep_node_index), diagnostics) = res;
 462
 463                 if tcx.sess.opts.debugging_opts.query_dep_graph {
 464                     tcx.dep_graph.mark_loaded_from_cache(dep_node_index, false);
 465                 }
 466
 467                 if dep_node.kind != ::dep_graph::DepKind::Null {
 468                     tcx.on_disk_query_result_cache
 469                        .store_diagnostics(dep_node_index, diagnostics);
 470                 }
 471
 472                 let value = QueryValue::new(result, dep_node_index);
 473
 474                 Ok(((&tcx.maps
 475                          .$name
 476                          .borrow_mut()
 477                          .map
 478                          .entry(key)
 479                          .or_insert(value)
 480                          .value).clone(),
 481                    dep_node_index))
 482             }
 483
 484             pub fn try_get(tcx: TyCtxt<'a, $tcx, 'lcx>, span: Span, key: $K)
 485                            -> Result<$V, DiagnosticBuilder<'a>> {
 486                 match Self::try_get_with(tcx, span, key) {
 487                     Ok(e) => Ok(e),
 488                     Err(e) => Err(tcx.report_cycle(e)),
 489                 }
 490             }
 491         })*
 492
 493         #[derive(Copy, Clone)]
 494         pub struct TyCtxtAt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
 495             pub tcx: TyCtxt<'a, 'gcx, 'tcx>,
 496             pub span: Span,
 497         }
 498
 499         impl<'a, 'gcx, 'tcx> Deref for TyCtxtAt<'a, 'gcx, 'tcx> {
 500             type Target = TyCtxt<'a, 'gcx, 'tcx>;
 501             fn deref(&self) -> &Self::Target {
 502                 &self.tcx
 503             }
 504         }
 505
 506         impl<'a, $tcx, 'lcx> TyCtxt<'a, $tcx, 'lcx> {
 507             /// Return a transparent wrapper for `TyCtxt` which uses
 508             /// `span` as the location of queries performed through it.
 509             pub fn at(self, span: Span) -> TyCtxtAt<'a, $tcx, 'lcx> {
 510                 TyCtxtAt {
 511                     tcx: self,
 512                     span
 513                 }
 514             }
 515
 516             $($(#[$attr])*
 517             pub fn $name(self, key: $K) -> $V {
 518                 self.at(DUMMY_SP).$name(key)
 519             })*
 520         }
 521
 522         impl<'a, $tcx, 'lcx> TyCtxtAt<'a, $tcx, 'lcx> {
 523             $($(#[$attr])*
 524             pub fn $name(self, key: $K) -> $V {
 525                 queries::$name::try_get(self.tcx, self.span, key).unwrap_or_else(|mut e| {
 526                     e.emit();
 527                     Value::from_cycle_error(self.global_tcx())
 528                 })
 529             })*
 530         }
 531
 532         define_provider_struct! {
 533             tcx: $tcx,
 534             input: ($(([$($modifiers)*] [$name] [$K] [$V]))*)
 535         }
 536
 537         impl<$tcx> Copy for Providers<$tcx> {}
 538         impl<$tcx> Clone for Providers<$tcx> {
 539             fn clone(&self) -> Self { *self }
 540         }
 541     }
 542 }
 543
 544 macro_rules! define_map_struct {
 545     (tcx: $tcx:tt,
 546      input: ($(([$(modifiers:tt)*] [$($attr:tt)*] [$name:ident]))*)) => {
 547         pub struct Maps<$tcx> {
 548             providers: IndexVec<CrateNum, Providers<$tcx>>,
 549             query_stack: RefCell<Vec<(Span, Query<$tcx>)>>,
 550             $($(#[$attr])*  $name: RefCell<QueryMap<queries::$name<$tcx>>>,)*
 551         }
 552     };
 553 }
 554
 555 macro_rules! define_provider_struct {
 556     (tcx: $tcx:tt,
 557      input: ($(([$($modifiers:tt)*] [$name:ident] [$K:ty] [$R:ty]))*)) => {
 558         pub struct Providers<$tcx> {
 559             $(pub $name: for<'a> fn(TyCtxt<'a, $tcx, $tcx>, $K) -> $R,)*
 560         }
 561
 562         impl<$tcx> Default for Providers<$tcx> {
 563             fn default() -> Self {
 564                 $(fn $name<'a, $tcx>(_: TyCtxt<'a, $tcx, $tcx>, key: $K) -> $R {
 565                     bug!("tcx.maps.{}({:?}) unsupported by its crate",
 566                          stringify!($name), key);
 567                 })*
 568                 Providers { $($name),* }
 569             }
 570         }
 571     };
 572 }
 573
 574
 575 /// The red/green evaluation system will try to mark a specific DepNode in the
 576 /// dependency graph as green by recursively trying to mark the dependencies of
 577 /// that DepNode as green. While doing so, it will sometimes encounter a DepNode
 578 /// where we don't know if it is red or green and we therefore actually have
 579 /// to recompute its value in order to find out. Since the only piece of
 580 /// information that we have at that point is the DepNode we are trying to
 581 /// re-evaluate, we need some way to re-run a query from just that. This is what
 582 /// `force_from_dep_node()` implements.
 583 ///
 584 /// In the general case, a DepNode consists of a DepKind and an opaque
 585 /// GUID/fingerprint that will uniquely identify the node. This GUID/fingerprint
 586 /// is usually constructed by computing a stable hash of the query-key that the
 587 /// DepNode corresponds to. Consequently, it is not in general possible to go
 588 /// back from hash to query-key (since hash functions are not reversible). For
 589 /// this reason `force_from_dep_node()` is expected to fail from time to time
 590 /// because we just cannot find out, from the DepNode alone, what the
 591 /// corresponding query-key is and therefore cannot re-run the query.
 592 ///
 593 /// The system deals with this case letting `try_mark_green` fail which forces
 594 /// the root query to be re-evaluated.
 595 ///
 596 /// Now, if force_from_dep_node() would always fail, it would be pretty useless.
 597 /// Fortunately, we can use some contextual information that will allow us to
 598 /// reconstruct query-keys for certain kinds of DepNodes. In particular, we
 599 /// enforce by construction that the GUID/fingerprint of certain DepNodes is a
 600 /// valid DefPathHash. Since we also always build a huge table that maps every
 601 /// DefPathHash in the current codebase to the corresponding DefId, we have
 602 /// everything we need to re-run the query.
 603 ///
 604 /// Take the `mir_validated` query as an example. Like many other queries, it
 605 /// just has a single parameter: the DefId of the item it will compute the
 606 /// validated MIR for. Now, when we call `force_from_dep_node()` on a dep-node
 607 /// with kind `MirValidated`, we know that the GUID/fingerprint of the dep-node
 608 /// is actually a DefPathHash, and can therefore just look up the corresponding
 609 /// DefId in `tcx.def_path_hash_to_def_id`.
 610 ///
 611 /// When you implement a new query, it will likely have a corresponding new
 612 /// DepKind, and you'll have to support it here in `force_from_dep_node()`. As
 613 /// a rule of thumb, if your query takes a DefId or DefIndex as sole parameter,
 614 /// then `force_from_dep_node()` should not fail for it. Otherwise, you can just
 615 /// add it to the "We don't have enough information to reconstruct..." group in
 616 /// the match below.
 617 pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
 618                                            dep_node: &DepNode)
 619                                            -> bool {
 620     use ty::maps::keys::Key;
 621     use hir::def_id::LOCAL_CRATE;
 622
 623     // We must avoid ever having to call force_from_dep_node() for a
 624     // DepNode::CodegenUnit:
 625     // Since we cannot reconstruct the query key of a DepNode::CodegenUnit, we
 626     // would always end up having to evaluate the first caller of the
 627     // `codegen_unit` query that *is* reconstructible. This might very well be
 628     // the `compile_codegen_unit` query, thus re-translating the whole CGU just
 629     // to re-trigger calling the `codegen_unit` query with the right key. At
 630     // that point we would already have re-done all the work we are trying to
 631     // avoid doing in the first place.
 632     // The solution is simple: Just explicitly call the `codegen_unit` query for
 633     // each CGU, right after partitioning. This way `try_mark_green` will always
 634     // hit the cache instead of having to go through `force_from_dep_node`.
 635     // This assertion makes sure, we actually keep applying the solution above.
 636     debug_assert!(dep_node.kind != DepKind::CodegenUnit,
 637                   "calling force_from_dep_node() on DepKind::CodegenUnit");
 638
 639     if !dep_node.kind.can_reconstruct_query_key() {
 640         return false
 641     }
 642
 643     macro_rules! def_id {
 644         () => {
 645             if let Some(def_id) = dep_node.extract_def_id(tcx) {
 646                 def_id
 647             } else {
 648                 // return from the whole function
 649                 return false
 650             }
 651         }
 652     };
 653
 654     macro_rules! krate {
 655         () => { (def_id!()).krate }
 656     };
 657
 658     macro_rules! force {
 659         ($query:ident, $key:expr) => {
 660             {
 661                 use $crate::util::common::{ProfileQueriesMsg, profq_msg};
 662
 663                 // FIXME(eddyb) Get more valid Span's on queries.
 664                 // def_span guard is necessary to prevent a recursive loop,
 665                 // default_span calls def_span query internally.
 666                 let span = if stringify!($query) != "def_span" {
 667                     $key.default_span(tcx)
 668                 } else {
 669                     ::syntax_pos::DUMMY_SP
 670                 };
 671
 672                 profq_msg!(tcx,
 673                     ProfileQueriesMsg::QueryBegin(
 674                         span.data(),
 675                         ::ty::maps::QueryMsg::$query(profq_key!(tcx, $key))
 676                     )
 677                 );
 678
 679                 match ::ty::maps::queries::$query::force(tcx, $key, span, *dep_node) {
 680                     Ok(_) => {},
 681                     Err(e) => {
 682                         tcx.report_cycle(e).emit();
 683                     }
 684                 }
 685             }
 686         }
 687     };
 688
 689     // FIXME(#45015): We should try move this boilerplate code into a macro
 690     //                somehow.
 691     match dep_node.kind {
 692         // These are inputs that are expected to be pre-allocated and that
 693         // should therefore always be red or green already
 694         DepKind::AllLocalTraitImpls |
 695         DepKind::Krate |
 696         DepKind::CrateMetadata |
 697         DepKind::HirBody |
 698         DepKind::Hir |
 699
 700         // This are anonymous nodes
 701         DepKind::TraitSelect |
 702
 703         // We don't have enough information to reconstruct the query key of
 704         // these
 705         DepKind::IsCopy |
 706         DepKind::IsSized |
 707         DepKind::IsFreeze |
 708         DepKind::NeedsDrop |
 709         DepKind::Layout |
 710         DepKind::ConstEval |
 711         DepKind::InstanceSymbolName |
 712         DepKind::MirShim |
 713         DepKind::BorrowCheckKrate |
 714         DepKind::Specializes |
 715         DepKind::ImplementationsOfTrait |
 716         DepKind::TypeParamPredicates |
 717         DepKind::CodegenUnit |
 718         DepKind::CompileCodegenUnit |
 719         DepKind::FulfillObligation |
 720         DepKind::VtableMethods |
 721         DepKind::EraseRegionsTy |
 722         DepKind::NormalizeTy |
 723
 724         // This one should never occur in this context
 725         DepKind::Null => {
 726             bug!("force_from_dep_node() - Encountered {:?}", dep_node.kind)
 727         }
 728
 729         // These are not queries
 730         DepKind::CoherenceCheckTrait |
 731         DepKind::ItemVarianceConstraints => {
 732             return false
 733         }
 734
 735         DepKind::RegionScopeTree => { force!(region_scope_tree, def_id!()); }
 736
 737         DepKind::Coherence => { force!(crate_inherent_impls, LOCAL_CRATE); }
 738         DepKind::CoherenceInherentImplOverlapCheck => {
 739             force!(crate_inherent_impls_overlap_check, LOCAL_CRATE)
 740         },
 741         DepKind::PrivacyAccessLevels => { force!(privacy_access_levels, LOCAL_CRATE); }
 742         DepKind::MirBuilt => { force!(mir_built, def_id!()); }
 743         DepKind::MirConstQualif => { force!(mir_const_qualif, def_id!()); }
 744         DepKind::MirConst => { force!(mir_const, def_id!()); }
 745         DepKind::MirValidated => { force!(mir_validated, def_id!()); }
 746         DepKind::MirOptimized => { force!(optimized_mir, def_id!()); }
 747
 748         DepKind::BorrowCheck => { force!(borrowck, def_id!()); }
 749         DepKind::MirBorrowCheck => { force!(mir_borrowck, def_id!()); }
 750         DepKind::UnsafetyCheckResult => { force!(unsafety_check_result, def_id!()); }
 751         DepKind::Reachability => { force!(reachable_set, LOCAL_CRATE); }
 752         DepKind::MirKeys => { force!(mir_keys, LOCAL_CRATE); }
 753         DepKind::CrateVariances => { force!(crate_variances, LOCAL_CRATE); }
 754         DepKind::AssociatedItems => { force!(associated_item, def_id!()); }
 755         DepKind::TypeOfItem => { force!(type_of, def_id!()); }
 756         DepKind::GenericsOfItem => { force!(generics_of, def_id!()); }
 757         DepKind::PredicatesOfItem => { force!(predicates_of, def_id!()); }
 758         DepKind::InferredOutlivesOf => { force!(inferred_outlives_of, def_id!()); }
 759         DepKind::SuperPredicatesOfItem => { force!(super_predicates_of, def_id!()); }
 760         DepKind::TraitDefOfItem => { force!(trait_def, def_id!()); }
 761         DepKind::AdtDefOfItem => { force!(adt_def, def_id!()); }
 762         DepKind::IsAutoImpl => { force!(is_auto_impl, def_id!()); }
 763         DepKind::ImplTraitRef => { force!(impl_trait_ref, def_id!()); }
 764         DepKind::ImplPolarity => { force!(impl_polarity, def_id!()); }
 765         DepKind::ClosureKind => { force!(closure_kind, def_id!()); }
 766         DepKind::FnSignature => { force!(fn_sig, def_id!()); }
 767         DepKind::GenSignature => { force!(generator_sig, def_id!()); }
 768         DepKind::CoerceUnsizedInfo => { force!(coerce_unsized_info, def_id!()); }
 769         DepKind::ItemVariances => { force!(variances_of, def_id!()); }
 770         DepKind::IsConstFn => { force!(is_const_fn, def_id!()); }
 771         DepKind::IsForeignItem => { force!(is_foreign_item, def_id!()); }
 772         DepKind::SizedConstraint => { force!(adt_sized_constraint, def_id!()); }
 773         DepKind::DtorckConstraint => { force!(adt_dtorck_constraint, def_id!()); }
 774         DepKind::AdtDestructor => { force!(adt_destructor, def_id!()); }
 775         DepKind::AssociatedItemDefIds => { force!(associated_item_def_ids, def_id!()); }
 776         DepKind::InherentImpls => { force!(inherent_impls, def_id!()); }
 777         DepKind::TypeckBodiesKrate => { force!(typeck_item_bodies, LOCAL_CRATE); }
 778         DepKind::TypeckTables => { force!(typeck_tables_of, def_id!()); }
 779         DepKind::UsedTraitImports => { force!(used_trait_imports, def_id!()); }
 780         DepKind::HasTypeckTables => { force!(has_typeck_tables, def_id!()); }
 781         DepKind::SymbolName => { force!(def_symbol_name, def_id!()); }
 782         DepKind::SpecializationGraph => { force!(specialization_graph_of, def_id!()); }
 783         DepKind::ObjectSafety => { force!(is_object_safe, def_id!()); }
 784         DepKind::TraitImpls => { force!(trait_impls_of, def_id!()); }
 785
 786         DepKind::ParamEnv => { force!(param_env, def_id!()); }
 787         DepKind::DescribeDef => { force!(describe_def, def_id!()); }
 788         DepKind::DefSpan => { force!(def_span, def_id!()); }
 789         DepKind::LookupStability => { force!(lookup_stability, def_id!()); }
 790         DepKind::LookupDeprecationEntry => {
 791             force!(lookup_deprecation_entry, def_id!());
 792         }
 793         DepKind::ItemBodyNestedBodies => { force!(item_body_nested_bodies, def_id!()); }
 794         DepKind::ConstIsRvaluePromotableToStatic => {
 795             force!(const_is_rvalue_promotable_to_static, def_id!());
 796         }
 797         DepKind::RvaluePromotableMap => { force!(rvalue_promotable_map, def_id!()); }
 798         DepKind::ImplParent => { force!(impl_parent, def_id!()); }
 799         DepKind::TraitOfItem => { force!(trait_of_item, def_id!()); }
 800         DepKind::IsExportedSymbol => { force!(is_exported_symbol, def_id!()); }
 801         DepKind::IsMirAvailable => { force!(is_mir_available, def_id!()); }
 802         DepKind::ItemAttrs => { force!(item_attrs, def_id!()); }
 803         DepKind::FnArgNames => { force!(fn_arg_names, def_id!()); }
 804         DepKind::DylibDepFormats => { force!(dylib_dependency_formats, krate!()); }
 805         DepKind::IsPanicRuntime => { force!(is_panic_runtime, krate!()); }
 806         DepKind::IsCompilerBuiltins => { force!(is_compiler_builtins, krate!()); }
 807         DepKind::HasGlobalAllocator => { force!(has_global_allocator, krate!()); }
 808         DepKind::ExternCrate => { force!(extern_crate, def_id!()); }
 809         DepKind::LintLevels => { force!(lint_levels, LOCAL_CRATE); }
 810         DepKind::InScopeTraits => { force!(in_scope_traits_map, def_id!().index); }
 811         DepKind::ModuleExports => { force!(module_exports, def_id!()); }
 812         DepKind::IsSanitizerRuntime => { force!(is_sanitizer_runtime, krate!()); }
 813         DepKind::IsProfilerRuntime => { force!(is_profiler_runtime, krate!()); }
 814         DepKind::GetPanicStrategy => { force!(panic_strategy, krate!()); }
 815         DepKind::IsNoBuiltins => { force!(is_no_builtins, krate!()); }
 816         DepKind::ImplDefaultness => { force!(impl_defaultness, def_id!()); }
 817         DepKind::ExportedSymbolIds => { force!(exported_symbol_ids, krate!()); }
 818         DepKind::NativeLibraries => { force!(native_libraries, krate!()); }
 819         DepKind::PluginRegistrarFn => { force!(plugin_registrar_fn, krate!()); }
 820         DepKind::DeriveRegistrarFn => { force!(derive_registrar_fn, krate!()); }
 821         DepKind::CrateDisambiguator => { force!(crate_disambiguator, krate!()); }
 822         DepKind::CrateHash => { force!(crate_hash, krate!()); }
 823         DepKind::OriginalCrateName => { force!(original_crate_name, krate!()); }
 824
 825         DepKind::AllTraitImplementations => {
 826             force!(all_trait_implementations, krate!());
 827         }
 828
 829         DepKind::IsDllimportForeignItem => {
 830             force!(is_dllimport_foreign_item, def_id!());
 831         }
 832         DepKind::IsStaticallyIncludedForeignItem => {
 833             force!(is_statically_included_foreign_item, def_id!());
 834         }
 835         DepKind::NativeLibraryKind => { force!(native_library_kind, def_id!()); }
 836         DepKind::LinkArgs => { force!(link_args, LOCAL_CRATE); }
 837
 838         DepKind::NamedRegion => { force!(named_region_map, def_id!().index); }
 839         DepKind::IsLateBound => { force!(is_late_bound_map, def_id!().index); }
 840         DepKind::ObjectLifetimeDefaults => {
 841             force!(object_lifetime_defaults_map, def_id!().index);
 842         }
 843
 844         DepKind::Visibility => { force!(visibility, def_id!()); }
 845         DepKind::DepKind => { force!(dep_kind, krate!()); }
 846         DepKind::CrateName => { force!(crate_name, krate!()); }
 847         DepKind::ItemChildren => { force!(item_children, def_id!()); }
 848         DepKind::ExternModStmtCnum => { force!(extern_mod_stmt_cnum, def_id!()); }
 849         DepKind::GetLangItems => { force!(get_lang_items, LOCAL_CRATE); }
 850         DepKind::DefinedLangItems => { force!(defined_lang_items, krate!()); }
 851         DepKind::MissingLangItems => { force!(missing_lang_items, krate!()); }
 852         DepKind::ExternConstBody => { force!(extern_const_body, def_id!()); }
 853         DepKind::VisibleParentMap => { force!(visible_parent_map, LOCAL_CRATE); }
 854         DepKind::MissingExternCrateItem => {
 855             force!(missing_extern_crate_item, krate!());
 856         }
 857         DepKind::UsedCrateSource => { force!(used_crate_source, krate!()); }
 858         DepKind::PostorderCnums => { force!(postorder_cnums, LOCAL_CRATE); }
 859         DepKind::HasCloneClosures => { force!(has_clone_closures, krate!()); }
 860         DepKind::HasCopyClosures => { force!(has_copy_closures, krate!()); }
 861
 862         DepKind::Freevars => { force!(freevars, def_id!()); }
 863         DepKind::MaybeUnusedTraitImport => {
 864             force!(maybe_unused_trait_import, def_id!());
 865         }
 866         DepKind::MaybeUnusedExternCrates => { force!(maybe_unused_extern_crates, LOCAL_CRATE); }
 867         DepKind::StabilityIndex => { force!(stability_index, LOCAL_CRATE); }
 868         DepKind::AllCrateNums => { force!(all_crate_nums, LOCAL_CRATE); }
 869         DepKind::ExportedSymbols => { force!(exported_symbols, krate!()); }
 870         DepKind::CollectAndPartitionTranslationItems => {
 871             force!(collect_and_partition_translation_items, LOCAL_CRATE);
 872         }
 873         DepKind::ExportName => { force!(export_name, def_id!()); }
 874         DepKind::ContainsExternIndicator => {
 875             force!(contains_extern_indicator, def_id!());
 876         }
 877         DepKind::IsTranslatedFunction => { force!(is_translated_function, def_id!()); }
 878         DepKind::OutputFilenames => { force!(output_filenames, LOCAL_CRATE); }
 879     }
 880
 881     true
 882 }