compiler/rustc_query_impl/src/plumbing.rs

   1 //! The implementation of the query system itself. This defines the macros that
   2 //! generate the actual methods on tcx which find and execute the provider,
   3 //! manage the caches, and so forth.
   4
   5 use crate::keys::Key;
   6 use crate::on_disk_cache::CacheDecoder;
   7 use crate::{on_disk_cache, Queries};
   8 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
   9 use rustc_data_structures::sync::{AtomicU64, Lock};
  10 use rustc_errors::{Diagnostic, Handler};
  11 use rustc_middle::dep_graph::{
  12     self, DepKind, DepKindStruct, DepNode, DepNodeIndex, SerializedDepNodeIndex,
  13 };
  14 use rustc_middle::ty::tls::{self, ImplicitCtxt};
  15 use rustc_middle::ty::{self, TyCtxt};
  16 use rustc_query_system::dep_graph::{DepNodeParams, HasDepContext};
  17 use rustc_query_system::ich::StableHashingContext;
  18 use rustc_query_system::query::{
  19     force_query, QueryConfig, QueryContext, QueryDescription, QueryJobId, QueryMap,
  20     QuerySideEffects, QueryStackFrame,
  21 };
  22 use rustc_query_system::Value;
  23 use rustc_serialize::Decodable;
  24 use std::any::Any;
  25 use std::num::NonZeroU64;
  26 use thin_vec::ThinVec;
  27
  28 #[derive(Copy, Clone)]
  29 pub struct QueryCtxt<'tcx> {
  30     pub tcx: TyCtxt<'tcx>,
  31     pub queries: &'tcx Queries<'tcx>,
  32 }
  33
  34 impl<'tcx> std::ops::Deref for QueryCtxt<'tcx> {
  35     type Target = TyCtxt<'tcx>;
  36
  37     #[inline]
  38     fn deref(&self) -> &Self::Target {
  39         &self.tcx
  40     }
  41 }
  42
  43 impl<'tcx> HasDepContext for QueryCtxt<'tcx> {
  44     type DepKind = rustc_middle::dep_graph::DepKind;
  45     type DepContext = TyCtxt<'tcx>;
  46
  47     #[inline]
  48     fn dep_context(&self) -> &Self::DepContext {
  49         &self.tcx
  50     }
  51 }
  52
  53 impl QueryContext for QueryCtxt<'_> {
  54     fn next_job_id(&self) -> QueryJobId {
  55         QueryJobId(
  56             NonZeroU64::new(
  57                 self.queries.jobs.fetch_add(1, rustc_data_structures::sync::Ordering::Relaxed),
  58             )
  59             .unwrap(),
  60         )
  61     }
  62
  63     fn current_query_job(&self) -> Option<QueryJobId> {
  64         tls::with_related_context(**self, |icx| icx.query)
  65     }
  66
  67     fn try_collect_active_jobs(&self) -> Option<QueryMap> {
  68         self.queries.try_collect_active_jobs(**self)
  69     }
  70
  71     // Interactions with on_disk_cache
  72     fn load_side_effects(&self, prev_dep_node_index: SerializedDepNodeIndex) -> QuerySideEffects {
  73         self.queries
  74             .on_disk_cache
  75             .as_ref()
  76             .map(|c| c.load_side_effects(**self, prev_dep_node_index))
  77             .unwrap_or_default()
  78     }
  79
  80     fn store_side_effects(&self, dep_node_index: DepNodeIndex, side_effects: QuerySideEffects) {
  81         if let Some(c) = self.queries.on_disk_cache.as_ref() {
  82             c.store_side_effects(dep_node_index, side_effects)
  83         }
  84     }
  85
  86     fn store_side_effects_for_anon_node(
  87         &self,
  88         dep_node_index: DepNodeIndex,
  89         side_effects: QuerySideEffects,
  90     ) {
  91         if let Some(c) = self.queries.on_disk_cache.as_ref() {
  92             c.store_side_effects_for_anon_node(dep_node_index, side_effects)
  93         }
  94     }
  95
  96     /// Executes a job by changing the `ImplicitCtxt` to point to the
  97     /// new query job while it executes. It returns the diagnostics
  98     /// captured during execution and the actual result.
  99     #[inline(always)]
 100     fn start_query<R>(
 101         &self,
 102         token: QueryJobId,
 103         depth_limit: bool,
 104         diagnostics: Option<&Lock<ThinVec<Diagnostic>>>,
 105         compute: impl FnOnce() -> R,
 106     ) -> R {
 107         // The `TyCtxt` stored in TLS has the same global interner lifetime
 108         // as `self`, so we use `with_related_context` to relate the 'tcx lifetimes
 109         // when accessing the `ImplicitCtxt`.
 110         tls::with_related_context(**self, move |current_icx| {
 111             if depth_limit && !self.recursion_limit().value_within_limit(current_icx.query_depth) {
 112                 self.depth_limit_error();
 113             }
 114
 115             // Update the `ImplicitCtxt` to point to our new query job.
 116             let new_icx = ImplicitCtxt {
 117                 tcx: **self,
 118                 query: Some(token),
 119                 diagnostics,
 120                 query_depth: current_icx.query_depth + depth_limit as usize,
 121                 task_deps: current_icx.task_deps,
 122             };
 123
 124             // Use the `ImplicitCtxt` while we execute the query.
 125             tls::enter_context(&new_icx, |_| {
 126                 rustc_data_structures::stack::ensure_sufficient_stack(compute)
 127             })
 128         })
 129     }
 130 }
 131
 132 impl<'tcx> QueryCtxt<'tcx> {
 133     #[inline]
 134     pub fn from_tcx(tcx: TyCtxt<'tcx>) -> Self {
 135         let queries = tcx.queries.as_any();
 136         let queries = unsafe {
 137             let queries = std::mem::transmute::<&dyn Any, &dyn Any>(queries);
 138             let queries = queries.downcast_ref().unwrap();
 139             let queries = std::mem::transmute::<&Queries<'_>, &Queries<'_>>(queries);
 140             queries
 141         };
 142         QueryCtxt { tcx, queries }
 143     }
 144
 145     pub(crate) fn on_disk_cache(self) -> Option<&'tcx on_disk_cache::OnDiskCache<'tcx>> {
 146         self.queries.on_disk_cache.as_ref()
 147     }
 148
 149     pub(super) fn encode_query_results(
 150         self,
 151         encoder: &mut on_disk_cache::CacheEncoder<'_, 'tcx>,
 152         query_result_index: &mut on_disk_cache::EncodedDepNodeIndex,
 153     ) {
 154         macro_rules! encode_queries {
 155             ($($query:ident,)*) => {
 156                 $(
 157                     on_disk_cache::encode_query_results::<_, super::queries::$query<'_>>(
 158                         self,
 159                         encoder,
 160                         query_result_index
 161                     );
 162                 )*
 163             }
 164         }
 165
 166         rustc_cached_queries!(encode_queries!);
 167     }
 168
 169     pub fn try_print_query_stack(
 170         self,
 171         query: Option<QueryJobId>,
 172         handler: &Handler,
 173         num_frames: Option<usize>,
 174     ) -> usize {
 175         rustc_query_system::query::print_query_stack(self, query, handler, num_frames)
 176     }
 177 }
 178
 179 macro_rules! handle_cycle_error {
 180     ([]) => {{
 181         rustc_query_system::HandleCycleError::Error
 182     }};
 183     ([(fatal_cycle) $($rest:tt)*]) => {{
 184         rustc_query_system::HandleCycleError::Fatal
 185     }};
 186     ([(cycle_delay_bug) $($rest:tt)*]) => {{
 187         rustc_query_system::HandleCycleError::DelayBug
 188     }};
 189     ([$other:tt $($modifiers:tt)*]) => {
 190         handle_cycle_error!([$($modifiers)*])
 191     };
 192 }
 193
 194 macro_rules! is_anon {
 195     ([]) => {{
 196         false
 197     }};
 198     ([(anon) $($rest:tt)*]) => {{
 199         true
 200     }};
 201     ([$other:tt $($modifiers:tt)*]) => {
 202         is_anon!([$($modifiers)*])
 203     };
 204 }
 205
 206 macro_rules! is_eval_always {
 207     ([]) => {{
 208         false
 209     }};
 210     ([(eval_always) $($rest:tt)*]) => {{
 211         true
 212     }};
 213     ([$other:tt $($modifiers:tt)*]) => {
 214         is_eval_always!([$($modifiers)*])
 215     };
 216 }
 217
 218 macro_rules! depth_limit {
 219     ([]) => {{
 220         false
 221     }};
 222     ([(depth_limit) $($rest:tt)*]) => {{
 223         true
 224     }};
 225     ([$other:tt $($modifiers:tt)*]) => {
 226         depth_limit!([$($modifiers)*])
 227     };
 228 }
 229
 230 macro_rules! hash_result {
 231     ([]) => {{
 232         Some(dep_graph::hash_result)
 233     }};
 234     ([(no_hash) $($rest:tt)*]) => {{
 235         None
 236     }};
 237     ([$other:tt $($modifiers:tt)*]) => {
 238         hash_result!([$($modifiers)*])
 239     };
 240 }
 241
 242 macro_rules! get_provider {
 243     ([][$tcx:expr, $name:ident, $key:expr]) => {{
 244         $tcx.queries.local_providers.$name
 245     }};
 246     ([(separate_provide_extern) $($rest:tt)*][$tcx:expr, $name:ident, $key:expr]) => {{
 247         if $key.query_crate_is_local() {
 248             $tcx.queries.local_providers.$name
 249         } else {
 250             $tcx.queries.extern_providers.$name
 251         }
 252     }};
 253     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 254         get_provider!([$($modifiers)*][$($args)*])
 255     };
 256 }
 257
 258 macro_rules! should_ever_cache_on_disk {
 259     ([]) => {{
 260         None
 261     }};
 262     ([(cache) $($rest:tt)*]) => {{
 263         Some($crate::plumbing::try_load_from_disk::<Self::Value>)
 264     }};
 265     ([$other:tt $($modifiers:tt)*]) => {
 266         should_ever_cache_on_disk!([$($modifiers)*])
 267     };
 268 }
 269
 270 pub(crate) fn create_query_frame<
 271     'tcx,
 272     K: Copy + Key + for<'a> HashStable<StableHashingContext<'a>>,
 273 >(
 274     tcx: QueryCtxt<'tcx>,
 275     do_describe: fn(QueryCtxt<'tcx>, K) -> String,
 276     key: K,
 277     kind: DepKind,
 278     name: &'static str,
 279 ) -> QueryStackFrame {
 280     // Disable visible paths printing for performance reasons.
 281     // Showing visible path instead of any path is not that important in production.
 282     let description = ty::print::with_no_visible_paths!(
 283         // Force filename-line mode to avoid invoking `type_of` query.
 284         ty::print::with_forced_impl_filename_line!(do_describe(tcx, key))
 285     );
 286     let description =
 287         if tcx.sess.verbose() { format!("{} [{}]", description, name) } else { description };
 288     let span = if kind == dep_graph::DepKind::def_span {
 289         // The `def_span` query is used to calculate `default_span`,
 290         // so exit to avoid infinite recursion.
 291         None
 292     } else {
 293         Some(key.default_span(*tcx))
 294     };
 295     let def_kind = if kind == dep_graph::DepKind::opt_def_kind {
 296         // Try to avoid infinite recursion.
 297         None
 298     } else {
 299         key.key_as_def_id()
 300             .and_then(|def_id| def_id.as_local())
 301             .and_then(|def_id| tcx.opt_def_kind(def_id))
 302     };
 303     let hash = || {
 304         tcx.with_stable_hashing_context(|mut hcx| {
 305             let mut hasher = StableHasher::new();
 306             std::mem::discriminant(&kind).hash_stable(&mut hcx, &mut hasher);
 307             key.hash_stable(&mut hcx, &mut hasher);
 308             hasher.finish::<u64>()
 309         })
 310     };
 311
 312     QueryStackFrame::new(name, description, span, def_kind, hash)
 313 }
 314
 315 fn try_load_from_on_disk_cache<'tcx, Q>(tcx: TyCtxt<'tcx>, dep_node: DepNode)
 316 where
 317     Q: QueryDescription<QueryCtxt<'tcx>>,
 318     Q::Key: DepNodeParams<TyCtxt<'tcx>>,
 319 {
 320     debug_assert!(tcx.dep_graph.is_green(&dep_node));
 321
 322     let key = Q::Key::recover(tcx, &dep_node).unwrap_or_else(|| {
 323         panic!("Failed to recover key for {:?} with hash {}", dep_node, dep_node.hash)
 324     });
 325     if Q::cache_on_disk(tcx, &key) {
 326         let _ = Q::execute_query(tcx, key);
 327     }
 328 }
 329
 330 pub(crate) fn try_load_from_disk<'tcx, V>(
 331     tcx: QueryCtxt<'tcx>,
 332     id: SerializedDepNodeIndex,
 333 ) -> Option<V>
 334 where
 335     V: for<'a> Decodable<CacheDecoder<'a, 'tcx>>,
 336 {
 337     tcx.on_disk_cache().as_ref()?.try_load_query_result(*tcx, id)
 338 }
 339
 340 fn force_from_dep_node<'tcx, Q>(tcx: TyCtxt<'tcx>, dep_node: DepNode) -> bool
 341 where
 342     Q: QueryDescription<QueryCtxt<'tcx>>,
 343     Q::Key: DepNodeParams<TyCtxt<'tcx>>,
 344     Q::Value: Value<TyCtxt<'tcx>>,
 345 {
 346     if let Some(key) = Q::Key::recover(tcx, &dep_node) {
 347         #[cfg(debug_assertions)]
 348         let _guard = tracing::span!(tracing::Level::TRACE, stringify!($name), ?key).entered();
 349         let tcx = QueryCtxt::from_tcx(tcx);
 350         force_query::<Q, _>(tcx, key, dep_node);
 351         true
 352     } else {
 353         false
 354     }
 355 }
 356
 357 pub(crate) fn query_callback<'tcx, Q: QueryConfig>(
 358     is_anon: bool,
 359     is_eval_always: bool,
 360 ) -> DepKindStruct<'tcx>
 361 where
 362     Q: QueryDescription<QueryCtxt<'tcx>>,
 363     Q::Key: DepNodeParams<TyCtxt<'tcx>>,
 364 {
 365     let fingerprint_style = Q::Key::fingerprint_style();
 366
 367     if is_anon || !fingerprint_style.reconstructible() {
 368         return DepKindStruct {
 369             is_anon,
 370             is_eval_always,
 371             fingerprint_style,
 372             force_from_dep_node: None,
 373             try_load_from_on_disk_cache: None,
 374         };
 375     }
 376
 377     DepKindStruct {
 378         is_anon,
 379         is_eval_always,
 380         fingerprint_style,
 381         force_from_dep_node: Some(force_from_dep_node::<Q>),
 382         try_load_from_on_disk_cache: Some(try_load_from_on_disk_cache::<Q>),
 383     }
 384 }
 385
 386 // NOTE: `$V` isn't used here, but we still need to match on it so it can be passed to other macros
 387 // invoked by `rustc_query_append`.
 388 macro_rules! define_queries {
 389     (
 390      $($(#[$attr:meta])*
 391         [$($modifiers:tt)*] fn $name:ident($($K:tt)*) -> $V:ty,)*) => {
 392         define_queries_struct! {
 393             input: ($(([$($modifiers)*] [$($attr)*] [$name]))*)
 394         }
 395
 396         #[allow(nonstandard_style)]
 397         mod queries {
 398             use std::marker::PhantomData;
 399
 400             $(pub struct $name<'tcx> {
 401                 data: PhantomData<&'tcx ()>
 402             })*
 403         }
 404
 405         $(impl<'tcx> QueryConfig for queries::$name<'tcx> {
 406             type Key = query_keys::$name<'tcx>;
 407             type Value = query_values::$name<'tcx>;
 408             type Stored = query_stored::$name<'tcx>;
 409             const NAME: &'static str = stringify!($name);
 410         }
 411
 412         impl<'tcx> QueryDescription<QueryCtxt<'tcx>> for queries::$name<'tcx> {
 413             rustc_query_description! { $name }
 414
 415             type Cache = query_storage::$name<'tcx>;
 416
 417             #[inline(always)]
 418             fn query_state<'a>(tcx: QueryCtxt<'tcx>) -> &'a QueryState<Self::Key>
 419                 where QueryCtxt<'tcx>: 'a
 420             {
 421                 &tcx.queries.$name
 422             }
 423
 424             #[inline(always)]
 425             fn query_cache<'a>(tcx: QueryCtxt<'tcx>) -> &'a Self::Cache
 426                 where 'tcx:'a
 427             {
 428                 &tcx.query_caches.$name
 429             }
 430
 431             #[inline]
 432             fn make_vtable(tcx: QueryCtxt<'tcx>, key: &Self::Key) ->
 433                 QueryVTable<QueryCtxt<'tcx>, Self::Key, Self::Value>
 434             {
 435                 let compute = get_provider!([$($modifiers)*][tcx, $name, key]);
 436                 let cache_on_disk = Self::cache_on_disk(tcx.tcx, key);
 437                 QueryVTable {
 438                     anon: is_anon!([$($modifiers)*]),
 439                     eval_always: is_eval_always!([$($modifiers)*]),
 440                     depth_limit: depth_limit!([$($modifiers)*]),
 441                     dep_kind: dep_graph::DepKind::$name,
 442                     hash_result: hash_result!([$($modifiers)*]),
 443                     handle_cycle_error: handle_cycle_error!([$($modifiers)*]),
 444                     compute,
 445                     try_load_from_disk: if cache_on_disk { should_ever_cache_on_disk!([$($modifiers)*]) } else { None },
 446                 }
 447             }
 448
 449             fn execute_query(tcx: TyCtxt<'tcx>, k: Self::Key) -> Self::Stored {
 450                 tcx.$name(k)
 451             }
 452         })*
 453
 454         #[allow(nonstandard_style)]
 455         mod query_callbacks {
 456             use super::*;
 457             use rustc_query_system::dep_graph::FingerprintStyle;
 458
 459             // We use this for most things when incr. comp. is turned off.
 460             pub fn Null<'tcx>() -> DepKindStruct<'tcx> {
 461                 DepKindStruct {
 462                     is_anon: false,
 463                     is_eval_always: false,
 464                     fingerprint_style: FingerprintStyle::Unit,
 465                     force_from_dep_node: Some(|_, dep_node| bug!("force_from_dep_node: encountered {:?}", dep_node)),
 466                     try_load_from_on_disk_cache: None,
 467                 }
 468             }
 469
 470             // We use this for the forever-red node.
 471             pub fn Red<'tcx>() -> DepKindStruct<'tcx> {
 472                 DepKindStruct {
 473                     is_anon: false,
 474                     is_eval_always: false,
 475                     fingerprint_style: FingerprintStyle::Unit,
 476                     force_from_dep_node: Some(|_, dep_node| bug!("force_from_dep_node: encountered {:?}", dep_node)),
 477                     try_load_from_on_disk_cache: None,
 478                 }
 479             }
 480
 481             pub fn TraitSelect<'tcx>() -> DepKindStruct<'tcx> {
 482                 DepKindStruct {
 483                     is_anon: true,
 484                     is_eval_always: false,
 485                     fingerprint_style: FingerprintStyle::Unit,
 486                     force_from_dep_node: None,
 487                     try_load_from_on_disk_cache: None,
 488                 }
 489             }
 490
 491             pub fn CompileCodegenUnit<'tcx>() -> DepKindStruct<'tcx> {
 492                 DepKindStruct {
 493                     is_anon: false,
 494                     is_eval_always: false,
 495                     fingerprint_style: FingerprintStyle::Opaque,
 496                     force_from_dep_node: None,
 497                     try_load_from_on_disk_cache: None,
 498                 }
 499             }
 500
 501             pub fn CompileMonoItem<'tcx>() -> DepKindStruct<'tcx> {
 502                 DepKindStruct {
 503                     is_anon: false,
 504                     is_eval_always: false,
 505                     fingerprint_style: FingerprintStyle::Opaque,
 506                     force_from_dep_node: None,
 507                     try_load_from_on_disk_cache: None,
 508                 }
 509             }
 510
 511             $(pub(crate) fn $name<'tcx>()-> DepKindStruct<'tcx> {
 512                 $crate::plumbing::query_callback::<queries::$name<'tcx>>(
 513                     is_anon!([$($modifiers)*]),
 514                     is_eval_always!([$($modifiers)*]),
 515                 )
 516             })*
 517         }
 518
 519         pub fn query_callbacks<'tcx>(arena: &'tcx Arena<'tcx>) -> &'tcx [DepKindStruct<'tcx>] {
 520             arena.alloc_from_iter(make_dep_kind_array!(query_callbacks))
 521         }
 522     }
 523 }
 524
 525 use crate::{ExternProviders, OnDiskCache, Providers};
 526
 527 impl<'tcx> Queries<'tcx> {
 528     pub fn new(
 529         local_providers: Providers,
 530         extern_providers: ExternProviders,
 531         on_disk_cache: Option<OnDiskCache<'tcx>>,
 532     ) -> Self {
 533         Queries {
 534             local_providers: Box::new(local_providers),
 535             extern_providers: Box::new(extern_providers),
 536             on_disk_cache,
 537             jobs: AtomicU64::new(1),
 538             ..Queries::default()
 539         }
 540     }
 541 }
 542
 543 macro_rules! define_queries_struct {
 544     (
 545      input: ($(([$($modifiers:tt)*] [$($attr:tt)*] [$name:ident]))*)) => {
 546         #[derive(Default)]
 547         pub struct Queries<'tcx> {
 548             local_providers: Box<Providers>,
 549             extern_providers: Box<ExternProviders>,
 550
 551             pub on_disk_cache: Option<OnDiskCache<'tcx>>,
 552
 553             jobs: AtomicU64,
 554
 555             $($(#[$attr])*  $name: QueryState<<queries::$name<'tcx> as QueryConfig>::Key>,)*
 556         }
 557
 558         impl<'tcx> Queries<'tcx> {
 559             pub(crate) fn try_collect_active_jobs(
 560                 &'tcx self,
 561                 tcx: TyCtxt<'tcx>,
 562             ) -> Option<QueryMap> {
 563                 let tcx = QueryCtxt { tcx, queries: self };
 564                 let mut jobs = QueryMap::default();
 565
 566                 $(
 567                     let make_query = |tcx, key| {
 568                         let kind = dep_graph::DepKind::$name;
 569                         let name = stringify!($name);
 570                         $crate::plumbing::create_query_frame(tcx, queries::$name::describe, key, kind, name)
 571                     };
 572                     self.$name.try_collect_active_jobs(
 573                         tcx,
 574                         make_query,
 575                         &mut jobs,
 576                     )?;
 577                 )*
 578
 579                 Some(jobs)
 580             }
 581         }
 582
 583         impl<'tcx> QueryEngine<'tcx> for Queries<'tcx> {
 584             fn as_any(&'tcx self) -> &'tcx dyn std::any::Any {
 585                 let this = unsafe { std::mem::transmute::<&Queries<'_>, &Queries<'_>>(self) };
 586                 this as _
 587             }
 588
 589             fn try_mark_green(&'tcx self, tcx: TyCtxt<'tcx>, dep_node: &dep_graph::DepNode) -> bool {
 590                 let qcx = QueryCtxt { tcx, queries: self };
 591                 tcx.dep_graph.try_mark_green(qcx, dep_node).is_some()
 592             }
 593
 594             $($(#[$attr])*
 595             #[inline(always)]
 596             #[tracing::instrument(level = "trace", skip(self, tcx), ret)]
 597             fn $name(
 598                 &'tcx self,
 599                 tcx: TyCtxt<'tcx>,
 600                 span: Span,
 601                 key: <queries::$name<'tcx> as QueryConfig>::Key,
 602                 mode: QueryMode,
 603             ) -> Option<query_stored::$name<'tcx>> {
 604                 let qcx = QueryCtxt { tcx, queries: self };
 605                 get_query::<queries::$name<'tcx>, _>(qcx, span, key, mode)
 606             })*
 607         }
 608     };
 609 }