src/librustc_interface/queries.rs

   1 use crate::interface::{Compiler, Result};
   2 use crate::passes::{self, BoxedResolver, QueryContext};
   3
   4 use rustc::arena::Arena;
   5 use rustc::dep_graph::DepGraph;
   6 use rustc::hir::map;
   7 use rustc::lint;
   8 use rustc::lint::LintStore;
   9 use rustc::session::config::{OutputFilenames, OutputType};
  10 use rustc::session::Session;
  11 use rustc::ty::steal::Steal;
  12 use rustc::ty::{AllArenas, GlobalCtxt, ResolverOutputs};
  13 use rustc::util::common::ErrorReported;
  14 use rustc_codegen_utils::codegen_backend::CodegenBackend;
  15 use rustc_data_structures::sync::{Lrc, Once, WorkerLocal};
  16 use rustc_hir::def_id::LOCAL_CRATE;
  17 use rustc_incremental::DepGraphFuture;
  18 use std::any::Any;
  19 use std::cell::{Ref, RefCell, RefMut};
  20 use std::mem;
  21 use std::rc::Rc;
  22 use syntax::{self, ast};
  23
  24 /// Represent the result of a query.
  25 /// This result can be stolen with the `take` method and generated with the `compute` method.
  26 pub struct Query<T> {
  27     result: RefCell<Option<Result<T>>>,
  28 }
  29
  30 impl<T> Query<T> {
  31     fn compute<F: FnOnce() -> Result<T>>(&self, f: F) -> Result<&Query<T>> {
  32         let mut result = self.result.borrow_mut();
  33         if result.is_none() {
  34             *result = Some(f());
  35         }
  36         result.as_ref().unwrap().as_ref().map(|_| self).map_err(|err| *err)
  37     }
  38
  39     /// Takes ownership of the query result. Further attempts to take or peek the query
  40     /// result will panic unless it is generated by calling the `compute` method.
  41     pub fn take(&self) -> T {
  42         self.result.borrow_mut().take().expect("missing query result").unwrap()
  43     }
  44
  45     /// Borrows the query result using the RefCell. Panics if the result is stolen.
  46     pub fn peek(&self) -> Ref<'_, T> {
  47         Ref::map(self.result.borrow(), |r| {
  48             r.as_ref().unwrap().as_ref().expect("missing query result")
  49         })
  50     }
  51
  52     /// Mutably borrows the query result using the RefCell. Panics if the result is stolen.
  53     pub fn peek_mut(&self) -> RefMut<'_, T> {
  54         RefMut::map(self.result.borrow_mut(), |r| {
  55             r.as_mut().unwrap().as_mut().expect("missing query result")
  56         })
  57     }
  58 }
  59
  60 impl<T> Default for Query<T> {
  61     fn default() -> Self {
  62         Query { result: RefCell::new(None) }
  63     }
  64 }
  65
  66 pub struct Queries<'tcx> {
  67     compiler: &'tcx Compiler,
  68     gcx: Once<GlobalCtxt<'tcx>>,
  69
  70     all_arenas: AllArenas,
  71     arena: WorkerLocal<Arena<'tcx>>,
  72
  73     dep_graph_future: Query<Option<DepGraphFuture>>,
  74     parse: Query<ast::Crate>,
  75     crate_name: Query<String>,
  76     register_plugins: Query<(ast::Crate, Lrc<LintStore>)>,
  77     expansion: Query<(ast::Crate, Steal<Rc<RefCell<BoxedResolver>>>, Lrc<LintStore>)>,
  78     dep_graph: Query<DepGraph>,
  79     lower_to_hir: Query<(&'tcx map::Forest<'tcx>, Steal<ResolverOutputs>)>,
  80     prepare_outputs: Query<OutputFilenames>,
  81     global_ctxt: Query<QueryContext<'tcx>>,
  82     ongoing_codegen: Query<Box<dyn Any>>,
  83 }
  84
  85 impl<'tcx> Queries<'tcx> {
  86     pub fn new(compiler: &'tcx Compiler) -> Queries<'tcx> {
  87         Queries {
  88             compiler,
  89             gcx: Once::new(),
  90             all_arenas: AllArenas::new(),
  91             arena: WorkerLocal::new(|_| Arena::default()),
  92             dep_graph_future: Default::default(),
  93             parse: Default::default(),
  94             crate_name: Default::default(),
  95             register_plugins: Default::default(),
  96             expansion: Default::default(),
  97             dep_graph: Default::default(),
  98             lower_to_hir: Default::default(),
  99             prepare_outputs: Default::default(),
 100             global_ctxt: Default::default(),
 101             ongoing_codegen: Default::default(),
 102         }
 103     }
 104
 105     fn session(&self) -> &Lrc<Session> {
 106         &self.compiler.sess
 107     }
 108     fn codegen_backend(&self) -> &Lrc<Box<dyn CodegenBackend>> {
 109         &self.compiler.codegen_backend()
 110     }
 111
 112     pub fn dep_graph_future(&self) -> Result<&Query<Option<DepGraphFuture>>> {
 113         self.dep_graph_future.compute(|| {
 114             Ok(self
 115                 .session()
 116                 .opts
 117                 .build_dep_graph()
 118                 .then(|| rustc_incremental::load_dep_graph(self.session())))
 119         })
 120     }
 121
 122     pub fn parse(&self) -> Result<&Query<ast::Crate>> {
 123         self.parse.compute(|| {
 124             passes::parse(self.session(), &self.compiler.input).map_err(|mut parse_error| {
 125                 parse_error.emit();
 126                 ErrorReported
 127             })
 128         })
 129     }
 130
 131     pub fn register_plugins(&self) -> Result<&Query<(ast::Crate, Lrc<LintStore>)>> {
 132         self.register_plugins.compute(|| {
 133             let crate_name = self.crate_name()?.peek().clone();
 134             let krate = self.parse()?.take();
 135
 136             let empty: &(dyn Fn(&Session, &mut lint::LintStore) + Sync + Send) = &|_, _| {};
 137             let result = passes::register_plugins(
 138                 self.session(),
 139                 &*self.codegen_backend().metadata_loader(),
 140                 self.compiler.register_lints.as_ref().map(|p| &**p).unwrap_or_else(|| empty),
 141                 krate,
 142                 &crate_name,
 143             );
 144
 145             // Compute the dependency graph (in the background). We want to do
 146             // this as early as possible, to give the DepGraph maximum time to
 147             // load before dep_graph() is called, but it also can't happen
 148             // until after rustc_incremental::prepare_session_directory() is
 149             // called, which happens within passes::register_plugins().
 150             self.dep_graph_future().ok();
 151
 152             result
 153         })
 154     }
 155
 156     pub fn crate_name(&self) -> Result<&Query<String>> {
 157         self.crate_name.compute(|| {
 158             Ok(match self.compiler.crate_name {
 159                 Some(ref crate_name) => crate_name.clone(),
 160                 None => {
 161                     let parse_result = self.parse()?;
 162                     let krate = parse_result.peek();
 163                     rustc_codegen_utils::link::find_crate_name(
 164                         Some(self.session()),
 165                         &krate.attrs,
 166                         &self.compiler.input,
 167                     )
 168                 }
 169             })
 170         })
 171     }
 172
 173     pub fn expansion(
 174         &self,
 175     ) -> Result<&Query<(ast::Crate, Steal<Rc<RefCell<BoxedResolver>>>, Lrc<LintStore>)>> {
 176         self.expansion.compute(|| {
 177             let crate_name = self.crate_name()?.peek().clone();
 178             let (krate, lint_store) = self.register_plugins()?.take();
 179             passes::configure_and_expand(
 180                 self.session().clone(),
 181                 lint_store.clone(),
 182                 self.codegen_backend().metadata_loader(),
 183                 krate,
 184                 &crate_name,
 185             )
 186             .map(|(krate, resolver)| {
 187                 (krate, Steal::new(Rc::new(RefCell::new(resolver))), lint_store)
 188             })
 189         })
 190     }
 191
 192     pub fn dep_graph(&self) -> Result<&Query<DepGraph>> {
 193         self.dep_graph.compute(|| {
 194             Ok(match self.dep_graph_future()?.take() {
 195                 None => DepGraph::new_disabled(),
 196                 Some(future) => {
 197                     let (prev_graph, prev_work_products) =
 198                         self.session().time("blocked_on_dep_graph_loading", || {
 199                             future
 200                                 .open()
 201                                 .unwrap_or_else(|e| rustc_incremental::LoadResult::Error {
 202                                     message: format!("could not decode incremental cache: {:?}", e),
 203                                 })
 204                                 .open(self.session())
 205                         });
 206                     DepGraph::new(prev_graph, prev_work_products)
 207                 }
 208             })
 209         })
 210     }
 211
 212     pub fn lower_to_hir(
 213         &'tcx self,
 214     ) -> Result<&Query<(&'tcx map::Forest<'tcx>, Steal<ResolverOutputs>)>> {
 215         self.lower_to_hir.compute(|| {
 216             let expansion_result = self.expansion()?;
 217             let peeked = expansion_result.peek();
 218             let krate = &peeked.0;
 219             let resolver = peeked.1.steal();
 220             let lint_store = &peeked.2;
 221             let hir = resolver.borrow_mut().access(|resolver| {
 222                 passes::lower_to_hir(
 223                     self.session(),
 224                     lint_store,
 225                     resolver,
 226                     &*self.dep_graph()?.peek(),
 227                     &krate,
 228                     &self.arena,
 229                 )
 230             })?;
 231             let hir = self.arena.alloc(hir);
 232             Ok((hir, Steal::new(BoxedResolver::to_resolver_outputs(resolver))))
 233         })
 234     }
 235
 236     pub fn prepare_outputs(&self) -> Result<&Query<OutputFilenames>> {
 237         self.prepare_outputs.compute(|| {
 238             let expansion_result = self.expansion()?;
 239             let (krate, boxed_resolver, _) = &*expansion_result.peek();
 240             let crate_name = self.crate_name()?;
 241             let crate_name = crate_name.peek();
 242             passes::prepare_outputs(
 243                 self.session(),
 244                 self.compiler,
 245                 &krate,
 246                 &boxed_resolver,
 247                 &crate_name,
 248             )
 249         })
 250     }
 251
 252     pub fn global_ctxt(&'tcx self) -> Result<&Query<QueryContext<'tcx>>> {
 253         self.global_ctxt.compute(|| {
 254             let crate_name = self.crate_name()?.peek().clone();
 255             let outputs = self.prepare_outputs()?.peek().clone();
 256             let lint_store = self.expansion()?.peek().2.clone();
 257             let hir = self.lower_to_hir()?.peek();
 258             let (ref hir_forest, ref resolver_outputs) = &*hir;
 259             Ok(passes::create_global_ctxt(
 260                 self.compiler,
 261                 lint_store,
 262                 hir_forest,
 263                 resolver_outputs.steal(),
 264                 outputs,
 265                 &crate_name,
 266                 &self.gcx,
 267                 &self.all_arenas,
 268                 &self.arena,
 269             ))
 270         })
 271     }
 272
 273     pub fn ongoing_codegen(&'tcx self) -> Result<&Query<Box<dyn Any>>> {
 274         self.ongoing_codegen.compute(|| {
 275             let outputs = self.prepare_outputs()?;
 276             self.global_ctxt()?.peek_mut().enter(|tcx| {
 277                 tcx.analysis(LOCAL_CRATE).ok();
 278
 279                 // Don't do code generation if there were any errors
 280                 self.session().compile_status()?;
 281
 282                 Ok(passes::start_codegen(&***self.codegen_backend(), tcx, &*outputs.peek()))
 283             })
 284         })
 285     }
 286
 287     pub fn linker(&'tcx self) -> Result<Linker> {
 288         let dep_graph = self.dep_graph()?;
 289         let prepare_outputs = self.prepare_outputs()?;
 290         let ongoing_codegen = self.ongoing_codegen()?;
 291
 292         let sess = self.session().clone();
 293         let codegen_backend = self.codegen_backend().clone();
 294
 295         Ok(Linker {
 296             sess,
 297             dep_graph: dep_graph.peek().clone(),
 298             prepare_outputs: prepare_outputs.take(),
 299             ongoing_codegen: ongoing_codegen.take(),
 300             codegen_backend,
 301         })
 302     }
 303 }
 304
 305 pub struct Linker {
 306     sess: Lrc<Session>,
 307     dep_graph: DepGraph,
 308     prepare_outputs: OutputFilenames,
 309     ongoing_codegen: Box<dyn Any>,
 310     codegen_backend: Lrc<Box<dyn CodegenBackend>>,
 311 }
 312
 313 impl Linker {
 314     pub fn link(self) -> Result<()> {
 315         self.codegen_backend
 316             .join_codegen_and_link(
 317                 self.ongoing_codegen,
 318                 &self.sess,
 319                 &self.dep_graph,
 320                 &self.prepare_outputs,
 321             )
 322             .map_err(|_| ErrorReported)
 323     }
 324 }
 325
 326 impl Compiler {
 327     pub fn enter<F, T>(&self, f: F) -> T
 328     where
 329         F: for<'tcx> FnOnce(&'tcx Queries<'tcx>) -> T,
 330     {
 331         let queries = Queries::new(&self);
 332         let ret = f(&queries);
 333
 334         if self.session().opts.debugging_opts.query_stats {
 335             if let Ok(gcx) = queries.global_ctxt() {
 336                 gcx.peek().print_stats();
 337             }
 338         }
 339
 340         ret
 341     }
 342
 343     // This method is different to all the other methods in `Compiler` because
 344     // it lacks a `Queries` entry. It's also not currently used. It does serve
 345     // as an example of how `Compiler` can be used, with additional steps added
 346     // between some passes. And see `rustc_driver::run_compiler` for a more
 347     // complex example.
 348     pub fn compile(&self) -> Result<()> {
 349         let linker = self.enter(|queries| {
 350             queries.prepare_outputs()?;
 351
 352             if self.session().opts.output_types.contains_key(&OutputType::DepInfo)
 353                 && self.session().opts.output_types.len() == 1
 354             {
 355                 return Ok(None);
 356             }
 357
 358             queries.global_ctxt()?;
 359
 360             // Drop AST after creating GlobalCtxt to free memory.
 361             mem::drop(queries.expansion()?.take());
 362
 363             queries.ongoing_codegen()?;
 364
 365             let linker = queries.linker()?;
 366             Ok(Some(linker))
 367         })?;
 368
 369         if let Some(linker) = linker {
 370             linker.link()?
 371         }
 372
 373         Ok(())
 374     }
 375 }