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::{on_disk_cache, Queries};
   6 use rustc_middle::dep_graph::{DepNodeIndex, SerializedDepNodeIndex};
   7 use rustc_middle::ty::tls::{self, ImplicitCtxt};
   8 use rustc_middle::ty::TyCtxt;
   9 use rustc_query_system::dep_graph::HasDepContext;
  10 use rustc_query_system::query::{QueryContext, QueryJobId, QueryMap, QuerySideEffects};
  11
  12 use rustc_data_structures::sync::Lock;
  13 use rustc_data_structures::thin_vec::ThinVec;
  14 use rustc_errors::{Diagnostic, Handler};
  15
  16 use std::any::Any;
  17 use std::num::NonZeroU64;
  18
  19 #[derive(Copy, Clone)]
  20 pub struct QueryCtxt<'tcx> {
  21     pub tcx: TyCtxt<'tcx>,
  22     pub queries: &'tcx Queries<'tcx>,
  23 }
  24
  25 impl<'tcx> std::ops::Deref for QueryCtxt<'tcx> {
  26     type Target = TyCtxt<'tcx>;
  27
  28     #[inline]
  29     fn deref(&self) -> &Self::Target {
  30         &self.tcx
  31     }
  32 }
  33
  34 impl<'tcx> HasDepContext for QueryCtxt<'tcx> {
  35     type DepKind = rustc_middle::dep_graph::DepKind;
  36     type DepContext = TyCtxt<'tcx>;
  37
  38     #[inline]
  39     fn dep_context(&self) -> &Self::DepContext {
  40         &self.tcx
  41     }
  42 }
  43
  44 impl QueryContext for QueryCtxt<'_> {
  45     fn next_job_id(&self) -> QueryJobId {
  46         QueryJobId(
  47             NonZeroU64::new(
  48                 self.queries.jobs.fetch_add(1, rustc_data_structures::sync::Ordering::Relaxed),
  49             )
  50             .unwrap(),
  51         )
  52     }
  53
  54     fn current_query_job(&self) -> Option<QueryJobId> {
  55         tls::with_related_context(**self, |icx| icx.query)
  56     }
  57
  58     fn try_collect_active_jobs(&self) -> Option<QueryMap> {
  59         self.queries.try_collect_active_jobs(**self)
  60     }
  61
  62     // Interactions with on_disk_cache
  63     fn load_side_effects(&self, prev_dep_node_index: SerializedDepNodeIndex) -> QuerySideEffects {
  64         self.queries
  65             .on_disk_cache
  66             .as_ref()
  67             .map(|c| c.load_side_effects(**self, prev_dep_node_index))
  68             .unwrap_or_default()
  69     }
  70
  71     fn store_side_effects(&self, dep_node_index: DepNodeIndex, side_effects: QuerySideEffects) {
  72         if let Some(c) = self.queries.on_disk_cache.as_ref() {
  73             c.store_side_effects(dep_node_index, side_effects)
  74         }
  75     }
  76
  77     fn store_side_effects_for_anon_node(
  78         &self,
  79         dep_node_index: DepNodeIndex,
  80         side_effects: QuerySideEffects,
  81     ) {
  82         if let Some(c) = self.queries.on_disk_cache.as_ref() {
  83             c.store_side_effects_for_anon_node(dep_node_index, side_effects)
  84         }
  85     }
  86
  87     /// Executes a job by changing the `ImplicitCtxt` to point to the
  88     /// new query job while it executes. It returns the diagnostics
  89     /// captured during execution and the actual result.
  90     #[inline(always)]
  91     fn start_query<R>(
  92         &self,
  93         token: QueryJobId,
  94         diagnostics: Option<&Lock<ThinVec<Diagnostic>>>,
  95         compute: impl FnOnce() -> R,
  96     ) -> R {
  97         // The `TyCtxt` stored in TLS has the same global interner lifetime
  98         // as `self`, so we use `with_related_context` to relate the 'tcx lifetimes
  99         // when accessing the `ImplicitCtxt`.
 100         tls::with_related_context(**self, move |current_icx| {
 101             // Update the `ImplicitCtxt` to point to our new query job.
 102             let new_icx = ImplicitCtxt {
 103                 tcx: **self,
 104                 query: Some(token),
 105                 diagnostics,
 106                 layout_depth: current_icx.layout_depth,
 107                 task_deps: current_icx.task_deps,
 108             };
 109
 110             // Use the `ImplicitCtxt` while we execute the query.
 111             tls::enter_context(&new_icx, |_| {
 112                 rustc_data_structures::stack::ensure_sufficient_stack(compute)
 113             })
 114         })
 115     }
 116 }
 117
 118 impl<'tcx> QueryCtxt<'tcx> {
 119     #[inline]
 120     pub fn from_tcx(tcx: TyCtxt<'tcx>) -> Self {
 121         let queries = tcx.queries.as_any();
 122         let queries = unsafe {
 123             let queries = std::mem::transmute::<&dyn Any, &dyn Any>(queries);
 124             let queries = queries.downcast_ref().unwrap();
 125             let queries = std::mem::transmute::<&Queries<'_>, &Queries<'_>>(queries);
 126             queries
 127         };
 128         QueryCtxt { tcx, queries }
 129     }
 130
 131     pub(crate) fn on_disk_cache(self) -> Option<&'tcx on_disk_cache::OnDiskCache<'tcx>> {
 132         self.queries.on_disk_cache.as_ref()
 133     }
 134
 135     #[cfg(parallel_compiler)]
 136     pub unsafe fn deadlock(self, registry: &rustc_rayon_core::Registry) {
 137         rustc_query_system::query::deadlock(self, registry)
 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 macro_rules! opt_remap_env_constness {
 242     ([][$name:ident]) => {};
 243     ([(remap_env_constness) $($rest:tt)*][$name:ident]) => {
 244         let $name = $name.without_const();
 245     };
 246     ([$other:tt $($modifiers:tt)*][$name:ident]) => {
 247         opt_remap_env_constness!([$($modifiers)*][$name])
 248     };
 249 }
 250
 251 macro_rules! define_queries {
 252     (<$tcx:tt>
 253      $($(#[$attr:meta])*
 254         [$($modifiers:tt)*] fn $name:ident($($K:tt)*) -> $V:ty,)*) => {
 255
 256         define_queries_struct! {
 257             tcx: $tcx,
 258             input: ($(([$($modifiers)*] [$($attr)*] [$name]))*)
 259         }
 260
 261         mod make_query {
 262             use super::*;
 263
 264             // Create an eponymous constructor for each query.
 265             $(#[allow(nonstandard_style)] $(#[$attr])*
 266             pub fn $name<$tcx>(tcx: QueryCtxt<$tcx>, key: query_keys::$name<$tcx>) -> QueryStackFrame {
 267                 opt_remap_env_constness!([$($modifiers)*][key]);
 268                 let kind = dep_graph::DepKind::$name;
 269                 let name = stringify!($name);
 270                 // Disable visible paths printing for performance reasons.
 271                 // Showing visible path instead of any path is not that important in production.
 272                 let description = ty::print::with_no_visible_paths!(
 273                     // Force filename-line mode to avoid invoking `type_of` query.
 274                     ty::print::with_forced_impl_filename_line!(
 275                         queries::$name::describe(tcx, key)
 276                     )
 277                 );
 278                 let description = if tcx.sess.verbose() {
 279                     format!("{} [{}]", description, name)
 280                 } else {
 281                     description
 282                 };
 283                 let span = if kind == dep_graph::DepKind::def_span {
 284                     // The `def_span` query is used to calculate `default_span`,
 285                     // so exit to avoid infinite recursion.
 286                     None
 287                 } else {
 288                     Some(key.default_span(*tcx))
 289                 };
 290                 // Use `tcx.hir().opt_def_kind()` to reduce the chance of
 291                 // accidentally triggering an infinite query loop.
 292                 let def_kind = key.key_as_def_id()
 293                     .and_then(|def_id| def_id.as_local())
 294                     .and_then(|def_id| tcx.hir().opt_def_kind(def_id));
 295                 let hash = || {
 296                     let mut hcx = tcx.create_stable_hashing_context();
 297                     let mut hasher = StableHasher::new();
 298                     std::mem::discriminant(&kind).hash_stable(&mut hcx, &mut hasher);
 299                     key.hash_stable(&mut hcx, &mut hasher);
 300                     hasher.finish::<u64>()
 301                 };
 302
 303                 QueryStackFrame::new(name, description, span, def_kind, hash)
 304             })*
 305         }
 306
 307         #[allow(nonstandard_style)]
 308         mod queries {
 309             use std::marker::PhantomData;
 310
 311             $(pub struct $name<$tcx> {
 312                 data: PhantomData<&$tcx ()>
 313             })*
 314         }
 315
 316         $(impl<$tcx> QueryConfig for queries::$name<$tcx> {
 317             type Key = query_keys::$name<$tcx>;
 318             type Value = query_values::$name<$tcx>;
 319             type Stored = query_stored::$name<$tcx>;
 320             const NAME: &'static str = stringify!($name);
 321         }
 322
 323         impl<$tcx> QueryDescription<QueryCtxt<$tcx>> for queries::$name<$tcx> {
 324             rustc_query_description! { $name<$tcx> }
 325
 326             type Cache = query_storage::$name<$tcx>;
 327
 328             #[inline(always)]
 329             fn query_state<'a>(tcx: QueryCtxt<$tcx>) -> &'a QueryState<Self::Key>
 330                 where QueryCtxt<$tcx>: 'a
 331             {
 332                 &tcx.queries.$name
 333             }
 334
 335             #[inline(always)]
 336             fn query_cache<'a>(tcx: QueryCtxt<$tcx>) -> &'a Self::Cache
 337                 where 'tcx:'a
 338             {
 339                 &tcx.query_caches.$name
 340             }
 341
 342             #[inline]
 343             fn make_vtable(tcx: QueryCtxt<'tcx>, key: &Self::Key) ->
 344                 QueryVtable<QueryCtxt<$tcx>, Self::Key, Self::Value>
 345             {
 346                 let compute = get_provider!([$($modifiers)*][tcx, $name, key]);
 347                 let cache_on_disk = Self::cache_on_disk(tcx.tcx, key);
 348                 QueryVtable {
 349                     anon: is_anon!([$($modifiers)*]),
 350                     eval_always: is_eval_always!([$($modifiers)*]),
 351                     dep_kind: dep_graph::DepKind::$name,
 352                     hash_result: hash_result!([$($modifiers)*]),
 353                     handle_cycle_error: |tcx, mut error| handle_cycle_error!([$($modifiers)*][tcx, error]),
 354                     compute,
 355                     cache_on_disk,
 356                     try_load_from_disk: Self::TRY_LOAD_FROM_DISK,
 357                 }
 358             }
 359         })*
 360
 361         #[allow(nonstandard_style)]
 362         mod query_callbacks {
 363             use super::*;
 364             use rustc_middle::dep_graph::DepNode;
 365             use rustc_middle::ty::query::query_keys;
 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             pub fn TraitSelect() -> DepKindStruct {
 382                 DepKindStruct {
 383                     is_anon: true,
 384                     is_eval_always: false,
 385                     fingerprint_style: FingerprintStyle::Unit,
 386                     force_from_dep_node: None,
 387                     try_load_from_on_disk_cache: None,
 388                 }
 389             }
 390
 391             pub fn CompileCodegenUnit() -> DepKindStruct {
 392                 DepKindStruct {
 393                     is_anon: false,
 394                     is_eval_always: false,
 395                     fingerprint_style: FingerprintStyle::Opaque,
 396                     force_from_dep_node: None,
 397                     try_load_from_on_disk_cache: None,
 398                 }
 399             }
 400
 401             pub fn CompileMonoItem() -> DepKindStruct {
 402                 DepKindStruct {
 403                     is_anon: false,
 404                     is_eval_always: false,
 405                     fingerprint_style: FingerprintStyle::Opaque,
 406                     force_from_dep_node: None,
 407                     try_load_from_on_disk_cache: None,
 408                 }
 409             }
 410
 411             $(pub(crate) fn $name()-> DepKindStruct {
 412                 let is_anon = is_anon!([$($modifiers)*]);
 413                 let is_eval_always = is_eval_always!([$($modifiers)*]);
 414
 415                 let fingerprint_style =
 416                     <query_keys::$name<'_> as DepNodeParams<TyCtxt<'_>>>::fingerprint_style();
 417
 418                 if is_anon || !fingerprint_style.reconstructible() {
 419                     return DepKindStruct {
 420                         is_anon,
 421                         is_eval_always,
 422                         fingerprint_style,
 423                         force_from_dep_node: None,
 424                         try_load_from_on_disk_cache: None,
 425                     }
 426                 }
 427
 428                 #[inline(always)]
 429                 fn recover<'tcx>(tcx: TyCtxt<'tcx>, dep_node: DepNode) -> Option<query_keys::$name<'tcx>> {
 430                     <query_keys::$name<'_> as DepNodeParams<TyCtxt<'_>>>::recover(tcx, &dep_node)
 431                 }
 432
 433                 fn force_from_dep_node(tcx: TyCtxt<'_>, dep_node: DepNode) -> bool {
 434                     if let Some(key) = recover(tcx, dep_node) {
 435                         #[cfg(debug_assertions)]
 436                         let _guard = tracing::span!(tracing::Level::TRACE, stringify!($name), ?key).entered();
 437                         let tcx = QueryCtxt::from_tcx(tcx);
 438                         force_query::<queries::$name<'_>, _>(tcx, key, dep_node);
 439                         true
 440                     } else {
 441                         false
 442                     }
 443                 }
 444
 445                 fn try_load_from_on_disk_cache(tcx: TyCtxt<'_>, dep_node: DepNode) {
 446                     debug_assert!(tcx.dep_graph.is_green(&dep_node));
 447
 448                     let key = recover(tcx, dep_node).unwrap_or_else(|| panic!("Failed to recover key for {:?} with hash {}", dep_node, dep_node.hash));
 449                     if queries::$name::cache_on_disk(tcx, &key) {
 450                         let _ = tcx.$name(key);
 451                     }
 452                 }
 453
 454                 DepKindStruct {
 455                     is_anon,
 456                     is_eval_always,
 457                     fingerprint_style,
 458                     force_from_dep_node: Some(force_from_dep_node),
 459                     try_load_from_on_disk_cache: Some(try_load_from_on_disk_cache),
 460                 }
 461             })*
 462         }
 463
 464         pub fn query_callbacks<'tcx>(arena: &'tcx Arena<'tcx>) -> &'tcx [DepKindStruct] {
 465             arena.alloc_from_iter(make_dep_kind_array!(query_callbacks))
 466         }
 467     }
 468 }
 469
 470 // FIXME(eddyb) this macro (and others?) use `$tcx` and `'tcx` interchangeably.
 471 // We should either not take `$tcx` at all and use `'tcx` everywhere, or use
 472 // `$tcx` everywhere (even if that isn't necessary due to lack of hygiene).
 473 macro_rules! define_queries_struct {
 474     (tcx: $tcx:tt,
 475      input: ($(([$($modifiers:tt)*] [$($attr:tt)*] [$name:ident]))*)) => {
 476         pub struct Queries<$tcx> {
 477             local_providers: Box<Providers>,
 478             extern_providers: Box<ExternProviders>,
 479
 480             pub on_disk_cache: Option<OnDiskCache<$tcx>>,
 481
 482             jobs: AtomicU64,
 483
 484             $($(#[$attr])*  $name: QueryState<query_keys::$name<$tcx>>,)*
 485         }
 486
 487         impl<$tcx> Queries<$tcx> {
 488             pub fn new(
 489                 local_providers: Providers,
 490                 extern_providers: ExternProviders,
 491                 on_disk_cache: Option<OnDiskCache<$tcx>>,
 492             ) -> Self {
 493                 Queries {
 494                     local_providers: Box::new(local_providers),
 495                     extern_providers: Box::new(extern_providers),
 496                     on_disk_cache,
 497                     jobs: AtomicU64::new(1),
 498                     $($name: Default::default()),*
 499                 }
 500             }
 501
 502             pub(crate) fn try_collect_active_jobs(
 503                 &$tcx self,
 504                 tcx: TyCtxt<$tcx>,
 505             ) -> Option<QueryMap> {
 506                 let tcx = QueryCtxt { tcx, queries: self };
 507                 let mut jobs = QueryMap::default();
 508
 509                 $(
 510                     self.$name.try_collect_active_jobs(
 511                         tcx,
 512                         make_query::$name,
 513                         &mut jobs,
 514                     )?;
 515                 )*
 516
 517                 Some(jobs)
 518             }
 519         }
 520
 521         impl<'tcx> QueryEngine<'tcx> for Queries<'tcx> {
 522             fn as_any(&'tcx self) -> &'tcx dyn std::any::Any {
 523                 let this = unsafe { std::mem::transmute::<&Queries<'_>, &Queries<'_>>(self) };
 524                 this as _
 525             }
 526
 527             fn try_mark_green(&'tcx self, tcx: TyCtxt<'tcx>, dep_node: &dep_graph::DepNode) -> bool {
 528                 let qcx = QueryCtxt { tcx, queries: self };
 529                 tcx.dep_graph.try_mark_green(qcx, dep_node).is_some()
 530             }
 531
 532             $($(#[$attr])*
 533             #[inline(always)]
 534             #[tracing::instrument(level = "trace", skip(self, tcx))]
 535             fn $name(
 536                 &'tcx self,
 537                 tcx: TyCtxt<$tcx>,
 538                 span: Span,
 539                 key: query_keys::$name<$tcx>,
 540                 mode: QueryMode,
 541             ) -> Option<query_stored::$name<$tcx>> {
 542                 opt_remap_env_constness!([$($modifiers)*][key]);
 543                 let qcx = QueryCtxt { tcx, queries: self };
 544                 get_query::<queries::$name<$tcx>, _>(qcx, span, key, mode)
 545             })*
 546         }
 547     };
 548 }