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     pub(super) fn encode_query_results(
 136         self,
 137         encoder: &mut on_disk_cache::CacheEncoder<'_, 'tcx>,
 138         query_result_index: &mut on_disk_cache::EncodedDepNodeIndex,
 139     ) {
 140         macro_rules! encode_queries {
 141             ($($query:ident,)*) => {
 142                 $(
 143                     on_disk_cache::encode_query_results::<_, super::queries::$query<'_>>(
 144                         self,
 145                         encoder,
 146                         query_result_index
 147                     );
 148                 )*
 149             }
 150         }
 151
 152         rustc_cached_queries!(encode_queries!);
 153     }
 154
 155     pub fn try_print_query_stack(
 156         self,
 157         query: Option<QueryJobId>,
 158         handler: &Handler,
 159         num_frames: Option<usize>,
 160     ) -> usize {
 161         rustc_query_system::query::print_query_stack(self, query, handler, num_frames)
 162     }
 163 }
 164
 165 macro_rules! handle_cycle_error {
 166     ([][$tcx: expr, $error:expr]) => {{
 167         $error.emit();
 168         Value::from_cycle_error($tcx)
 169     }};
 170     ([(fatal_cycle) $($rest:tt)*][$tcx:expr, $error:expr]) => {{
 171         $error.emit();
 172         $tcx.sess.abort_if_errors();
 173         unreachable!()
 174     }};
 175     ([(cycle_delay_bug) $($rest:tt)*][$tcx:expr, $error:expr]) => {{
 176         $error.delay_as_bug();
 177         Value::from_cycle_error($tcx)
 178     }};
 179     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 180         handle_cycle_error!([$($modifiers)*][$($args)*])
 181     };
 182 }
 183
 184 macro_rules! is_anon {
 185     ([]) => {{
 186         false
 187     }};
 188     ([(anon) $($rest:tt)*]) => {{
 189         true
 190     }};
 191     ([$other:tt $($modifiers:tt)*]) => {
 192         is_anon!([$($modifiers)*])
 193     };
 194 }
 195
 196 macro_rules! is_eval_always {
 197     ([]) => {{
 198         false
 199     }};
 200     ([(eval_always) $($rest:tt)*]) => {{
 201         true
 202     }};
 203     ([$other:tt $($modifiers:tt)*]) => {
 204         is_eval_always!([$($modifiers)*])
 205     };
 206 }
 207
 208 macro_rules! hash_result {
 209     ([]) => {{
 210         Some(dep_graph::hash_result)
 211     }};
 212     ([(no_hash) $($rest:tt)*]) => {{
 213         None
 214     }};
 215     ([$other:tt $($modifiers:tt)*]) => {
 216         hash_result!([$($modifiers)*])
 217     };
 218 }
 219
 220 macro_rules! get_provider {
 221     ([][$tcx:expr, $name:ident, $key:expr]) => {{
 222         $tcx.queries.local_providers.$name
 223     }};
 224     ([(separate_provide_extern) $($rest:tt)*][$tcx:expr, $name:ident, $key:expr]) => {{
 225         if $key.query_crate_is_local() {
 226             $tcx.queries.local_providers.$name
 227         } else {
 228             $tcx.queries.extern_providers.$name
 229         }
 230     }};
 231     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 232         get_provider!([$($modifiers)*][$($args)*])
 233     };
 234 }
 235
 236 macro_rules! opt_remap_env_constness {
 237     ([][$name:ident]) => {};
 238     ([(remap_env_constness) $($rest:tt)*][$name:ident]) => {
 239         let $name = $name.without_const();
 240     };
 241     ([$other:tt $($modifiers:tt)*][$name:ident]) => {
 242         opt_remap_env_constness!([$($modifiers)*][$name])
 243     };
 244 }
 245
 246 macro_rules! define_queries {
 247     (<$tcx:tt>
 248      $($(#[$attr:meta])*
 249         [$($modifiers:tt)*] fn $name:ident($($K:tt)*) -> $V:ty,)*) => {
 250
 251         define_queries_struct! {
 252             tcx: $tcx,
 253             input: ($(([$($modifiers)*] [$($attr)*] [$name]))*)
 254         }
 255
 256         mod make_query {
 257             use super::*;
 258
 259             // Create an eponymous constructor for each query.
 260             $(#[allow(nonstandard_style)] $(#[$attr])*
 261             pub fn $name<$tcx>(tcx: QueryCtxt<$tcx>, key: query_keys::$name<$tcx>) -> QueryStackFrame {
 262                 opt_remap_env_constness!([$($modifiers)*][key]);
 263                 let kind = dep_graph::DepKind::$name;
 264                 let name = stringify!($name);
 265                 // Disable visible paths printing for performance reasons.
 266                 // Showing visible path instead of any path is not that important in production.
 267                 let description = ty::print::with_no_visible_paths!(
 268                     // Force filename-line mode to avoid invoking `type_of` query.
 269                     ty::print::with_forced_impl_filename_line!(
 270                         queries::$name::describe(tcx, key)
 271                     )
 272                 );
 273                 let description = if tcx.sess.verbose() {
 274                     format!("{} [{}]", description, name)
 275                 } else {
 276                     description
 277                 };
 278                 let span = if kind == dep_graph::DepKind::def_span {
 279                     // The `def_span` query is used to calculate `default_span`,
 280                     // so exit to avoid infinite recursion.
 281                     None
 282                 } else {
 283                     Some(key.default_span(*tcx))
 284                 };
 285                 // Use `tcx.hir().opt_def_kind()` to reduce the chance of
 286                 // accidentally triggering an infinite query loop.
 287                 let def_kind = key.key_as_def_id()
 288                     .and_then(|def_id| def_id.as_local())
 289                     .and_then(|def_id| tcx.hir().opt_def_kind(def_id));
 290                 let hash = || {
 291                     let mut hcx = tcx.create_stable_hashing_context();
 292                     let mut hasher = StableHasher::new();
 293                     std::mem::discriminant(&kind).hash_stable(&mut hcx, &mut hasher);
 294                     key.hash_stable(&mut hcx, &mut hasher);
 295                     hasher.finish::<u64>()
 296                 };
 297
 298                 QueryStackFrame::new(name, description, span, def_kind, hash)
 299             })*
 300         }
 301
 302         #[allow(nonstandard_style)]
 303         mod queries {
 304             use std::marker::PhantomData;
 305
 306             $(pub struct $name<$tcx> {
 307                 data: PhantomData<&$tcx ()>
 308             })*
 309         }
 310
 311         $(impl<$tcx> QueryConfig for queries::$name<$tcx> {
 312             type Key = query_keys::$name<$tcx>;
 313             type Value = query_values::$name<$tcx>;
 314             type Stored = query_stored::$name<$tcx>;
 315             const NAME: &'static str = stringify!($name);
 316         }
 317
 318         impl<$tcx> QueryDescription<QueryCtxt<$tcx>> for queries::$name<$tcx> {
 319             rustc_query_description! { $name<$tcx> }
 320
 321             type Cache = query_storage::$name<$tcx>;
 322
 323             #[inline(always)]
 324             fn query_state<'a>(tcx: QueryCtxt<$tcx>) -> &'a QueryState<Self::Key>
 325                 where QueryCtxt<$tcx>: 'a
 326             {
 327                 &tcx.queries.$name
 328             }
 329
 330             #[inline(always)]
 331             fn query_cache<'a>(tcx: QueryCtxt<$tcx>) -> &'a Self::Cache
 332                 where 'tcx:'a
 333             {
 334                 &tcx.query_caches.$name
 335             }
 336
 337             #[inline]
 338             fn make_vtable(tcx: QueryCtxt<'tcx>, key: &Self::Key) ->
 339                 QueryVtable<QueryCtxt<$tcx>, Self::Key, Self::Value>
 340             {
 341                 let compute = get_provider!([$($modifiers)*][tcx, $name, key]);
 342                 let cache_on_disk = Self::cache_on_disk(tcx.tcx, key);
 343                 QueryVtable {
 344                     anon: is_anon!([$($modifiers)*]),
 345                     eval_always: is_eval_always!([$($modifiers)*]),
 346                     dep_kind: dep_graph::DepKind::$name,
 347                     hash_result: hash_result!([$($modifiers)*]),
 348                     handle_cycle_error: |tcx, mut error| handle_cycle_error!([$($modifiers)*][tcx, error]),
 349                     compute,
 350                     cache_on_disk,
 351                     try_load_from_disk: Self::TRY_LOAD_FROM_DISK,
 352                 }
 353             }
 354         })*
 355
 356         #[allow(nonstandard_style)]
 357         mod query_callbacks {
 358             use super::*;
 359             use rustc_middle::dep_graph::DepNode;
 360             use rustc_middle::ty::query::query_keys;
 361             use rustc_query_system::dep_graph::DepNodeParams;
 362             use rustc_query_system::query::{force_query, QueryDescription};
 363             use rustc_query_system::dep_graph::FingerprintStyle;
 364
 365             // We use this for most things when incr. comp. is turned off.
 366             pub fn Null() -> DepKindStruct {
 367                 DepKindStruct {
 368                     is_anon: false,
 369                     is_eval_always: false,
 370                     fingerprint_style: FingerprintStyle::Unit,
 371                     force_from_dep_node: Some(|_, dep_node| bug!("force_from_dep_node: encountered {:?}", dep_node)),
 372                     try_load_from_on_disk_cache: None,
 373                 }
 374             }
 375
 376             pub fn TraitSelect() -> DepKindStruct {
 377                 DepKindStruct {
 378                     is_anon: true,
 379                     is_eval_always: false,
 380                     fingerprint_style: FingerprintStyle::Unit,
 381                     force_from_dep_node: None,
 382                     try_load_from_on_disk_cache: None,
 383                 }
 384             }
 385
 386             pub fn CompileCodegenUnit() -> DepKindStruct {
 387                 DepKindStruct {
 388                     is_anon: false,
 389                     is_eval_always: false,
 390                     fingerprint_style: FingerprintStyle::Opaque,
 391                     force_from_dep_node: None,
 392                     try_load_from_on_disk_cache: None,
 393                 }
 394             }
 395
 396             pub fn CompileMonoItem() -> DepKindStruct {
 397                 DepKindStruct {
 398                     is_anon: false,
 399                     is_eval_always: false,
 400                     fingerprint_style: FingerprintStyle::Opaque,
 401                     force_from_dep_node: None,
 402                     try_load_from_on_disk_cache: None,
 403                 }
 404             }
 405
 406             $(pub(crate) fn $name()-> DepKindStruct {
 407                 let is_anon = is_anon!([$($modifiers)*]);
 408                 let is_eval_always = is_eval_always!([$($modifiers)*]);
 409
 410                 let fingerprint_style =
 411                     <query_keys::$name<'_> as DepNodeParams<TyCtxt<'_>>>::fingerprint_style();
 412
 413                 if is_anon || !fingerprint_style.reconstructible() {
 414                     return DepKindStruct {
 415                         is_anon,
 416                         is_eval_always,
 417                         fingerprint_style,
 418                         force_from_dep_node: None,
 419                         try_load_from_on_disk_cache: None,
 420                     }
 421                 }
 422
 423                 #[inline(always)]
 424                 fn recover<'tcx>(tcx: TyCtxt<'tcx>, dep_node: DepNode) -> Option<query_keys::$name<'tcx>> {
 425                     <query_keys::$name<'_> as DepNodeParams<TyCtxt<'_>>>::recover(tcx, &dep_node)
 426                 }
 427
 428                 fn force_from_dep_node(tcx: TyCtxt<'_>, dep_node: DepNode) -> bool {
 429                     if let Some(key) = recover(tcx, dep_node) {
 430                         #[cfg(debug_assertions)]
 431                         let _guard = tracing::span!(tracing::Level::TRACE, stringify!($name), ?key).entered();
 432                         let tcx = QueryCtxt::from_tcx(tcx);
 433                         force_query::<queries::$name<'_>, _>(tcx, key, dep_node);
 434                         true
 435                     } else {
 436                         false
 437                     }
 438                 }
 439
 440                 fn try_load_from_on_disk_cache(tcx: TyCtxt<'_>, dep_node: DepNode) {
 441                     debug_assert!(tcx.dep_graph.is_green(&dep_node));
 442
 443                     let key = recover(tcx, dep_node).unwrap_or_else(|| panic!("Failed to recover key for {:?} with hash {}", dep_node, dep_node.hash));
 444                     if queries::$name::cache_on_disk(tcx, &key) {
 445                         let _ = tcx.$name(key);
 446                     }
 447                 }
 448
 449                 DepKindStruct {
 450                     is_anon,
 451                     is_eval_always,
 452                     fingerprint_style,
 453                     force_from_dep_node: Some(force_from_dep_node),
 454                     try_load_from_on_disk_cache: Some(try_load_from_on_disk_cache),
 455                 }
 456             })*
 457         }
 458
 459         pub fn query_callbacks<'tcx>(arena: &'tcx Arena<'tcx>) -> &'tcx [DepKindStruct] {
 460             arena.alloc_from_iter(make_dep_kind_array!(query_callbacks))
 461         }
 462     }
 463 }
 464
 465 // FIXME(eddyb) this macro (and others?) use `$tcx` and `'tcx` interchangeably.
 466 // We should either not take `$tcx` at all and use `'tcx` everywhere, or use
 467 // `$tcx` everywhere (even if that isn't necessary due to lack of hygiene).
 468 macro_rules! define_queries_struct {
 469     (tcx: $tcx:tt,
 470      input: ($(([$($modifiers:tt)*] [$($attr:tt)*] [$name:ident]))*)) => {
 471         pub struct Queries<$tcx> {
 472             local_providers: Box<Providers>,
 473             extern_providers: Box<ExternProviders>,
 474
 475             pub on_disk_cache: Option<OnDiskCache<$tcx>>,
 476
 477             jobs: AtomicU64,
 478
 479             $($(#[$attr])*  $name: QueryState<query_keys::$name<$tcx>>,)*
 480         }
 481
 482         impl<$tcx> Queries<$tcx> {
 483             pub fn new(
 484                 local_providers: Providers,
 485                 extern_providers: ExternProviders,
 486                 on_disk_cache: Option<OnDiskCache<$tcx>>,
 487             ) -> Self {
 488                 Queries {
 489                     local_providers: Box::new(local_providers),
 490                     extern_providers: Box::new(extern_providers),
 491                     on_disk_cache,
 492                     jobs: AtomicU64::new(1),
 493                     $($name: Default::default()),*
 494                 }
 495             }
 496
 497             pub(crate) fn try_collect_active_jobs(
 498                 &$tcx self,
 499                 tcx: TyCtxt<$tcx>,
 500             ) -> Option<QueryMap> {
 501                 let tcx = QueryCtxt { tcx, queries: self };
 502                 let mut jobs = QueryMap::default();
 503
 504                 $(
 505                     self.$name.try_collect_active_jobs(
 506                         tcx,
 507                         make_query::$name,
 508                         &mut jobs,
 509                     )?;
 510                 )*
 511
 512                 Some(jobs)
 513             }
 514         }
 515
 516         impl<'tcx> QueryEngine<'tcx> for Queries<'tcx> {
 517             fn as_any(&'tcx self) -> &'tcx dyn std::any::Any {
 518                 let this = unsafe { std::mem::transmute::<&Queries<'_>, &Queries<'_>>(self) };
 519                 this as _
 520             }
 521
 522             fn try_mark_green(&'tcx self, tcx: TyCtxt<'tcx>, dep_node: &dep_graph::DepNode) -> bool {
 523                 let qcx = QueryCtxt { tcx, queries: self };
 524                 tcx.dep_graph.try_mark_green(qcx, dep_node).is_some()
 525             }
 526
 527             $($(#[$attr])*
 528             #[inline(always)]
 529             #[tracing::instrument(level = "trace", skip(self, tcx))]
 530             fn $name(
 531                 &'tcx self,
 532                 tcx: TyCtxt<$tcx>,
 533                 span: Span,
 534                 key: query_keys::$name<$tcx>,
 535                 mode: QueryMode,
 536             ) -> Option<query_stored::$name<$tcx>> {
 537                 opt_remap_env_constness!([$($modifiers)*][key]);
 538                 let qcx = QueryCtxt { tcx, queries: self };
 539                 get_query::<queries::$name<$tcx>, _>(qcx, span, key, mode)
 540             })*
 541         }
 542     };
 543 }