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