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