compiler/rustc_interface/src/queries.rs

   1 use crate::interface::{Compiler, Result};
   2 use crate::passes::{self, BoxedResolver, QueryContext};
   3
   4 use rustc_ast as ast;
   5 use rustc_codegen_ssa::traits::CodegenBackend;
   6 use rustc_data_structures::steal::Steal;
   7 use rustc_data_structures::svh::Svh;
   8 use rustc_data_structures::sync::{Lrc, OnceCell, WorkerLocal};
   9 use rustc_errors::ErrorReported;
  10 use rustc_hir::def_id::LOCAL_CRATE;
  11 use rustc_hir::Crate;
  12 use rustc_incremental::DepGraphFuture;
  13 use rustc_lint::LintStore;
  14 use rustc_middle::arena::Arena;
  15 use rustc_middle::dep_graph::DepGraph;
  16 use rustc_middle::ty::{GlobalCtxt, ResolverOutputs, TyCtxt};
  17 use rustc_query_impl::Queries as TcxQueries;
  18 use rustc_serialize::json;
  19 use rustc_session::config::{self, OutputFilenames, OutputType};
  20 use rustc_session::{output::find_crate_name, Session};
  21 use rustc_span::symbol::sym;
  22 use std::any::Any;
  23 use std::cell::{Ref, RefCell, RefMut};
  24 use std::rc::Rc;
  25
  26 /// Represent the result of a query.
  27 ///
  28 /// This result can be stolen with the [`take`] method and generated with the [`compute`] method.
  29 ///
  30 /// [`take`]: Self::take
  31 /// [`compute`]: Self::compute
  32 pub struct Query<T> {
  33     result: RefCell<Option<Result<T>>>,
  34 }
  35
  36 impl<T> Query<T> {
  37     fn compute<F: FnOnce() -> Result<T>>(&self, f: F) -> Result<&Query<T>> {
  38         let mut result = self.result.borrow_mut();
  39         if result.is_none() {
  40             *result = Some(f());
  41         }
  42         result.as_ref().unwrap().as_ref().map(|_| self).map_err(|err| *err)
  43     }
  44
  45     /// Takes ownership of the query result. Further attempts to take or peek the query
  46     /// result will panic unless it is generated by calling the `compute` method.
  47     pub fn take(&self) -> T {
  48         self.result.borrow_mut().take().expect("missing query result").unwrap()
  49     }
  50
  51     /// Borrows the query result using the RefCell. Panics if the result is stolen.
  52     pub fn peek(&self) -> Ref<'_, T> {
  53         Ref::map(self.result.borrow(), |r| {
  54             r.as_ref().unwrap().as_ref().expect("missing query result")
  55         })
  56     }
  57
  58     /// Mutably borrows the query result using the RefCell. Panics if the result is stolen.
  59     pub fn peek_mut(&self) -> RefMut<'_, T> {
  60         RefMut::map(self.result.borrow_mut(), |r| {
  61             r.as_mut().unwrap().as_mut().expect("missing query result")
  62         })
  63     }
  64 }
  65
  66 impl<T> Default for Query<T> {
  67     fn default() -> Self {
  68         Query { result: RefCell::new(None) }
  69     }
  70 }
  71
  72 pub struct Queries<'tcx> {
  73     compiler: &'tcx Compiler,
  74     gcx: OnceCell<GlobalCtxt<'tcx>>,
  75     queries: OnceCell<TcxQueries<'tcx>>,
  76
  77     arena: WorkerLocal<Arena<'tcx>>,
  78     hir_arena: WorkerLocal<rustc_ast_lowering::Arena<'tcx>>,
  79
  80     dep_graph_future: Query<Option<DepGraphFuture>>,
  81     parse: Query<ast::Crate>,
  82     crate_name: Query<String>,
  83     register_plugins: Query<(ast::Crate, Lrc<LintStore>)>,
  84     expansion: Query<(ast::Crate, Steal<Rc<RefCell<BoxedResolver>>>, Lrc<LintStore>)>,
  85     dep_graph: Query<DepGraph>,
  86     lower_to_hir: Query<(&'tcx Crate<'tcx>, Steal<ResolverOutputs>)>,
  87     prepare_outputs: Query<OutputFilenames>,
  88     global_ctxt: Query<QueryContext<'tcx>>,
  89     ongoing_codegen: Query<Box<dyn Any>>,
  90 }
  91
  92 impl<'tcx> Queries<'tcx> {
  93     pub fn new(compiler: &'tcx Compiler) -> Queries<'tcx> {
  94         Queries {
  95             compiler,
  96             gcx: OnceCell::new(),
  97             queries: OnceCell::new(),
  98             arena: WorkerLocal::new(|_| Arena::default()),
  99             hir_arena: WorkerLocal::new(|_| rustc_ast_lowering::Arena::default()),
 100             dep_graph_future: Default::default(),
 101             parse: Default::default(),
 102             crate_name: Default::default(),
 103             register_plugins: Default::default(),
 104             expansion: Default::default(),
 105             dep_graph: Default::default(),
 106             lower_to_hir: Default::default(),
 107             prepare_outputs: Default::default(),
 108             global_ctxt: Default::default(),
 109             ongoing_codegen: Default::default(),
 110         }
 111     }
 112
 113     fn session(&self) -> &Lrc<Session> {
 114         &self.compiler.sess
 115     }
 116     fn codegen_backend(&self) -> &Lrc<Box<dyn CodegenBackend>> {
 117         &self.compiler.codegen_backend()
 118     }
 119
 120     pub fn dep_graph_future(&self) -> Result<&Query<Option<DepGraphFuture>>> {
 121         self.dep_graph_future.compute(|| {
 122             Ok(self
 123                 .session()
 124                 .opts
 125                 .build_dep_graph()
 126                 .then(|| rustc_incremental::load_dep_graph(self.session())))
 127         })
 128     }
 129
 130     pub fn parse(&self) -> Result<&Query<ast::Crate>> {
 131         self.parse.compute(|| {
 132             passes::parse(self.session(), &self.compiler.input).map_err(|mut parse_error| {
 133                 parse_error.emit();
 134                 ErrorReported
 135             })
 136         })
 137     }
 138
 139     pub fn register_plugins(&self) -> Result<&Query<(ast::Crate, Lrc<LintStore>)>> {
 140         self.register_plugins.compute(|| {
 141             let crate_name = self.crate_name()?.peek().clone();
 142             let krate = self.parse()?.take();
 143
 144             let empty: &(dyn Fn(&Session, &mut LintStore) + Sync + Send) = &|_, _| {};
 145             let result = passes::register_plugins(
 146                 self.session(),
 147                 &*self.codegen_backend().metadata_loader(),
 148                 self.compiler.register_lints.as_deref().unwrap_or_else(|| empty),
 149                 krate,
 150                 &crate_name,
 151             );
 152
 153             // Compute the dependency graph (in the background). We want to do
 154             // this as early as possible, to give the DepGraph maximum time to
 155             // load before dep_graph() is called, but it also can't happen
 156             // until after rustc_incremental::prepare_session_directory() is
 157             // called, which happens within passes::register_plugins().
 158             self.dep_graph_future().ok();
 159
 160             result
 161         })
 162     }
 163
 164     pub fn crate_name(&self) -> Result<&Query<String>> {
 165         self.crate_name.compute(|| {
 166             Ok({
 167                 let parse_result = self.parse()?;
 168                 let krate = parse_result.peek();
 169                 // parse `#[crate_name]` even if `--crate-name` was passed, to make sure it matches.
 170                 find_crate_name(self.session(), &krate.attrs, &self.compiler.input)
 171             })
 172         })
 173     }
 174
 175     pub fn expansion(
 176         &self,
 177     ) -> Result<&Query<(ast::Crate, Steal<Rc<RefCell<BoxedResolver>>>, Lrc<LintStore>)>> {
 178         tracing::trace!("expansion");
 179         self.expansion.compute(|| {
 180             let crate_name = self.crate_name()?.peek().clone();
 181             let (krate, lint_store) = self.register_plugins()?.take();
 182             let _timer = self.session().timer("configure_and_expand");
 183             passes::configure_and_expand(
 184                 self.session().clone(),
 185                 lint_store.clone(),
 186                 self.codegen_backend().metadata_loader(),
 187                 krate,
 188                 &crate_name,
 189             )
 190             .map(|(krate, resolver)| {
 191                 (krate, Steal::new(Rc::new(RefCell::new(resolver))), lint_store)
 192             })
 193         })
 194     }
 195
 196     pub fn dep_graph(&self) -> Result<&Query<DepGraph>> {
 197         self.dep_graph.compute(|| {
 198             Ok(match self.dep_graph_future()?.take() {
 199                 None => DepGraph::new_disabled(),
 200                 Some(future) => {
 201                     let (prev_graph, prev_work_products) =
 202                         self.session().time("blocked_on_dep_graph_loading", || {
 203                             future
 204                                 .open()
 205                                 .unwrap_or_else(|e| rustc_incremental::LoadResult::Error {
 206                                     message: format!("could not decode incremental cache: {:?}", e),
 207                                 })
 208                                 .open(self.session())
 209                         });
 210
 211                     rustc_incremental::build_dep_graph(
 212                         self.session(),
 213                         prev_graph,
 214                         prev_work_products,
 215                     )
 216                     .unwrap_or_else(DepGraph::new_disabled)
 217                 }
 218             })
 219         })
 220     }
 221
 222     pub fn lower_to_hir(&'tcx self) -> Result<&Query<(&'tcx Crate<'tcx>, Steal<ResolverOutputs>)>> {
 223         self.lower_to_hir.compute(|| {
 224             let expansion_result = self.expansion()?;
 225             let peeked = expansion_result.peek();
 226             let krate = &peeked.0;
 227             let resolver = peeked.1.steal();
 228             let lint_store = &peeked.2;
 229             let hir = resolver.borrow_mut().access(|resolver| {
 230                 Ok(passes::lower_to_hir(
 231                     self.session(),
 232                     lint_store,
 233                     resolver,
 234                     &*self.dep_graph()?.peek(),
 235                     &krate,
 236                     &self.hir_arena,
 237                 ))
 238             })?;
 239             let hir = self.hir_arena.alloc(hir);
 240             Ok((hir, Steal::new(BoxedResolver::to_resolver_outputs(resolver))))
 241         })
 242     }
 243
 244     pub fn prepare_outputs(&self) -> Result<&Query<OutputFilenames>> {
 245         self.prepare_outputs.compute(|| {
 246             let expansion_result = self.expansion()?;
 247             let (krate, boxed_resolver, _) = &*expansion_result.peek();
 248             let crate_name = self.crate_name()?;
 249             let crate_name = crate_name.peek();
 250             passes::prepare_outputs(
 251                 self.session(),
 252                 self.compiler,
 253                 &krate,
 254                 &boxed_resolver,
 255                 &crate_name,
 256             )
 257         })
 258     }
 259
 260     pub fn global_ctxt(&'tcx self) -> Result<&Query<QueryContext<'tcx>>> {
 261         self.global_ctxt.compute(|| {
 262             let crate_name = self.crate_name()?.peek().clone();
 263             let outputs = self.prepare_outputs()?.peek().clone();
 264             let lint_store = self.expansion()?.peek().2.clone();
 265             let hir = self.lower_to_hir()?.peek();
 266             let dep_graph = self.dep_graph()?.peek().clone();
 267             let (ref krate, ref resolver_outputs) = &*hir;
 268             let _timer = self.session().timer("create_global_ctxt");
 269             Ok(passes::create_global_ctxt(
 270                 self.compiler,
 271                 lint_store,
 272                 krate,
 273                 dep_graph,
 274                 resolver_outputs.steal(),
 275                 outputs,
 276                 &crate_name,
 277                 &self.queries,
 278                 &self.gcx,
 279                 &self.arena,
 280             ))
 281         })
 282     }
 283
 284     pub fn ongoing_codegen(&'tcx self) -> Result<&Query<Box<dyn Any>>> {
 285         self.ongoing_codegen.compute(|| {
 286             let outputs = self.prepare_outputs()?;
 287             self.global_ctxt()?.peek_mut().enter(|tcx| {
 288                 tcx.analysis(LOCAL_CRATE).ok();
 289
 290                 // Don't do code generation if there were any errors
 291                 self.session().compile_status()?;
 292
 293                 // Hook for UI tests.
 294                 Self::check_for_rustc_errors_attr(tcx);
 295
 296                 Ok(passes::start_codegen(&***self.codegen_backend(), tcx, &*outputs.peek()))
 297             })
 298         })
 299     }
 300
 301     /// Check for the `#[rustc_error]` annotation, which forces an error in codegen. This is used
 302     /// to write UI tests that actually test that compilation succeeds without reporting
 303     /// an error.
 304     fn check_for_rustc_errors_attr(tcx: TyCtxt<'_>) {
 305         let def_id = match tcx.entry_fn(LOCAL_CRATE) {
 306             Some((def_id, _)) => def_id,
 307             _ => return,
 308         };
 309
 310         let attrs = &*tcx.get_attrs(def_id.to_def_id());
 311         let attrs = attrs.iter().filter(|attr| tcx.sess.check_name(attr, sym::rustc_error));
 312         for attr in attrs {
 313             match attr.meta_item_list() {
 314                 // Check if there is a `#[rustc_error(delay_span_bug_from_inside_query)]`.
 315                 Some(list)
 316                     if list.iter().any(|list_item| {
 317                         matches!(
 318                             list_item.ident().map(|i| i.name),
 319                             Some(sym::delay_span_bug_from_inside_query)
 320                         )
 321                     }) =>
 322                 {
 323                     tcx.ensure().trigger_delay_span_bug(def_id);
 324                 }
 325
 326                 // Bare `#[rustc_error]`.
 327                 None => {
 328                     tcx.sess.span_fatal(
 329                         tcx.def_span(def_id),
 330                         "fatal error triggered by #[rustc_error]",
 331                     );
 332                 }
 333
 334                 // Some other attribute.
 335                 Some(_) => {
 336                     tcx.sess.span_warn(
 337                         tcx.def_span(def_id),
 338                         "unexpected annotation used with `#[rustc_error(...)]!",
 339                     );
 340                 }
 341             }
 342         }
 343     }
 344
 345     pub fn linker(&'tcx self) -> Result<Linker> {
 346         let dep_graph = self.dep_graph()?;
 347         let prepare_outputs = self.prepare_outputs()?;
 348         let crate_hash = self.global_ctxt()?.peek_mut().enter(|tcx| tcx.crate_hash(LOCAL_CRATE));
 349         let ongoing_codegen = self.ongoing_codegen()?;
 350
 351         let sess = self.session().clone();
 352         let codegen_backend = self.codegen_backend().clone();
 353
 354         Ok(Linker {
 355             sess,
 356             dep_graph: dep_graph.peek().clone(),
 357             prepare_outputs: prepare_outputs.take(),
 358             crate_hash,
 359             ongoing_codegen: ongoing_codegen.take(),
 360             codegen_backend,
 361         })
 362     }
 363 }
 364
 365 pub struct Linker {
 366     sess: Lrc<Session>,
 367     dep_graph: DepGraph,
 368     prepare_outputs: OutputFilenames,
 369     crate_hash: Svh,
 370     ongoing_codegen: Box<dyn Any>,
 371     codegen_backend: Lrc<Box<dyn CodegenBackend>>,
 372 }
 373
 374 impl Linker {
 375     pub fn link(self) -> Result<()> {
 376         let (codegen_results, work_products) =
 377             self.codegen_backend.join_codegen(self.ongoing_codegen, &self.sess)?;
 378
 379         self.sess.compile_status()?;
 380
 381         let sess = &self.sess;
 382         let dep_graph = self.dep_graph;
 383         sess.time("serialize_work_products", || {
 384             rustc_incremental::save_work_product_index(&sess, &dep_graph, work_products)
 385         });
 386
 387         let prof = self.sess.prof.clone();
 388         prof.generic_activity("drop_dep_graph").run(move || drop(dep_graph));
 389
 390         // Now that we won't touch anything in the incremental compilation directory
 391         // any more, we can finalize it (which involves renaming it)
 392         rustc_incremental::finalize_session_directory(&self.sess, self.crate_hash);
 393
 394         if !self
 395             .sess
 396             .opts
 397             .output_types
 398             .keys()
 399             .any(|&i| i == OutputType::Exe || i == OutputType::Metadata)
 400         {
 401             return Ok(());
 402         }
 403
 404         if sess.opts.debugging_opts.no_link {
 405             // FIXME: use a binary format to encode the `.rlink` file
 406             let rlink_data = json::encode(&codegen_results).map_err(|err| {
 407                 sess.fatal(&format!("failed to encode rlink: {}", err));
 408             })?;
 409             let rlink_file = self.prepare_outputs.with_extension(config::RLINK_EXT);
 410             std::fs::write(&rlink_file, rlink_data).map_err(|err| {
 411                 sess.fatal(&format!("failed to write file {}: {}", rlink_file.display(), err));
 412             })?;
 413             return Ok(());
 414         }
 415
 416         let _timer = sess.prof.verbose_generic_activity("link_crate");
 417         self.codegen_backend.link(&self.sess, codegen_results, &self.prepare_outputs)
 418     }
 419 }
 420
 421 impl Compiler {
 422     pub fn enter<F, T>(&self, f: F) -> T
 423     where
 424         F: for<'tcx> FnOnce(&'tcx Queries<'tcx>) -> T,
 425     {
 426         let mut _timer = None;
 427         let queries = Queries::new(&self);
 428         let ret = f(&queries);
 429
 430         // NOTE: intentionally does not compute the global context if it hasn't been built yet,
 431         // since that likely means there was a parse error.
 432         if let Some(Ok(gcx)) = &mut *queries.global_ctxt.result.borrow_mut() {
 433             // We assume that no queries are run past here. If there are new queries
 434             // after this point, they'll show up as "<unknown>" in self-profiling data.
 435             {
 436                 let _prof_timer =
 437                     queries.session().prof.generic_activity("self_profile_alloc_query_strings");
 438                 gcx.enter(rustc_query_impl::alloc_self_profile_query_strings);
 439             }
 440
 441             if self.session().opts.debugging_opts.query_stats {
 442                 gcx.enter(rustc_query_impl::print_stats);
 443             }
 444
 445             self.session()
 446                 .time("serialize_dep_graph", || gcx.enter(rustc_incremental::save_dep_graph));
 447         }
 448
 449         _timer = Some(self.session().timer("free_global_ctxt"));
 450
 451         ret
 452     }
 453 }