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