src/librustc_interface/queries.rs

   1 use crate::interface::{Compiler, Result};
   2 use crate::passes::{self, BoxedResolver, ExpansionResult, BoxedGlobalCtxt, PluginInfo};
   3
   4 use rustc_incremental::DepGraphFuture;
   5 use rustc::session::config::{OutputFilenames, OutputType};
   6 use rustc::util::common::{time, ErrorReported};
   7 use rustc::hir;
   8 use rustc::hir::def_id::LOCAL_CRATE;
   9 use rustc::ty::steal::Steal;
  10 use rustc::dep_graph::DepGraph;
  11 use std::cell::{Ref, RefMut, RefCell};
  12 use std::rc::Rc;
  13 use std::sync::mpsc;
  14 use std::any::Any;
  15 use std::mem;
  16 use syntax::{self, ast};
  17
  18 /// Represent the result of a query.
  19 /// This result can be stolen with the `take` method and returned with the `give` method.
  20 pub struct Query<T> {
  21     result: RefCell<Option<Result<T>>>,
  22 }
  23
  24 impl<T> Query<T> {
  25     fn compute<F: FnOnce() -> Result<T>>(&self, f: F) -> Result<&Query<T>> {
  26         let mut result = self.result.borrow_mut();
  27         if result.is_none() {
  28             *result = Some(f());
  29         }
  30         result.as_ref().unwrap().as_ref().map(|_| self).map_err(|err| *err)
  31     }
  32
  33     /// Takes ownership of the query result. Further attempts to take or peek the query
  34     /// result will panic unless it is returned by calling the `give` method.
  35     pub fn take(&self) -> T {
  36         self.result
  37             .borrow_mut()
  38             .take()
  39             .expect("missing query result")
  40             .unwrap()
  41     }
  42
  43     /// Returns a stolen query result. Panics if there's already a result.
  44     pub fn give(&self, value: T) {
  45         let mut result = self.result.borrow_mut();
  46         assert!(result.is_none(), "a result already exists");
  47         *result = Some(Ok(value));
  48     }
  49
  50     /// Borrows the query result using the RefCell. Panics if the result is stolen.
  51     pub fn peek(&self) -> Ref<'_, T> {
  52         Ref::map(self.result.borrow(), |r| {
  53             r.as_ref().unwrap().as_ref().expect("missing query result")
  54         })
  55     }
  56
  57     /// Mutably borrows the query result using the RefCell. Panics if the result is stolen.
  58     pub fn peek_mut(&self) -> RefMut<'_, T> {
  59         RefMut::map(self.result.borrow_mut(), |r| {
  60             r.as_mut().unwrap().as_mut().expect("missing query result")
  61         })
  62     }
  63 }
  64
  65 impl<T> Default for Query<T> {
  66     fn default() -> Self {
  67         Query {
  68             result: RefCell::new(None),
  69         }
  70     }
  71 }
  72
  73 #[derive(Default)]
  74 pub(crate) struct Queries {
  75     dep_graph_future: Query<Option<DepGraphFuture>>,
  76     parse: Query<ast::Crate>,
  77     crate_name: Query<String>,
  78     register_plugins: Query<(ast::Crate, PluginInfo)>,
  79     expansion: Query<(ast::Crate, Rc<Option<RefCell<BoxedResolver>>>)>,
  80     dep_graph: Query<DepGraph>,
  81     lower_to_hir: Query<(Steal<hir::map::Forest>, ExpansionResult)>,
  82     prepare_outputs: Query<OutputFilenames>,
  83     codegen_channel: Query<(Steal<mpsc::Sender<Box<dyn Any + Send>>>,
  84                             Steal<mpsc::Receiver<Box<dyn Any + Send>>>)>,
  85     global_ctxt: Query<BoxedGlobalCtxt>,
  86     ongoing_codegen: Query<Box<dyn Any>>,
  87     link: Query<()>,
  88 }
  89
  90 impl Compiler {
  91     pub fn dep_graph_future(&self) -> Result<&Query<Option<DepGraphFuture>>> {
  92         self.queries.dep_graph_future.compute(|| {
  93             Ok(if self.session().opts.build_dep_graph() {
  94                 Some(rustc_incremental::load_dep_graph(self.session()))
  95             } else {
  96                 None
  97             })
  98         })
  99     }
 100
 101     pub fn parse(&self) -> Result<&Query<ast::Crate>> {
 102         self.queries.parse.compute(|| {
 103             passes::parse(self.session(), &self.input).map_err(
 104                 |mut parse_error| {
 105                     parse_error.emit();
 106                     ErrorReported
 107                 },
 108             )
 109         })
 110     }
 111
 112     pub fn register_plugins(&self) -> Result<&Query<(ast::Crate, PluginInfo)>> {
 113         self.queries.register_plugins.compute(|| {
 114             let crate_name = self.crate_name()?.peek().clone();
 115             let krate = self.parse()?.take();
 116
 117             passes::register_plugins(
 118                 self,
 119                 self.session(),
 120                 self.cstore(),
 121                 krate,
 122                 &crate_name,
 123             )
 124         })
 125     }
 126
 127     pub fn crate_name(&self) -> Result<&Query<String>> {
 128         self.queries.crate_name.compute(|| {
 129             let parse_result = self.parse()?;
 130             let krate = parse_result.peek();
 131             let result = match self.crate_name {
 132                 Some(ref crate_name) => crate_name.clone(),
 133                 None => rustc_codegen_utils::link::find_crate_name(
 134                     Some(self.session()),
 135                     &krate.attrs,
 136                     &self.input
 137                 ),
 138             };
 139             Ok(result)
 140         })
 141     }
 142
 143     pub fn expansion(
 144         &self
 145     ) -> Result<&Query<(ast::Crate, Rc<Option<RefCell<BoxedResolver>>>)>> {
 146         self.queries.expansion.compute(|| {
 147             let crate_name = self.crate_name()?.peek().clone();
 148             let (krate, plugin_info) = self.register_plugins()?.take();
 149             passes::configure_and_expand(
 150                 self.sess.clone(),
 151                 self.cstore().clone(),
 152                 krate,
 153                 &crate_name,
 154                 plugin_info,
 155             ).map(|(krate, resolver)| (krate, Rc::new(Some(RefCell::new(resolver)))))
 156         })
 157     }
 158
 159     pub fn dep_graph(&self) -> Result<&Query<DepGraph>> {
 160         self.queries.dep_graph.compute(|| {
 161             Ok(match self.dep_graph_future()?.take() {
 162                 None => DepGraph::new_disabled(),
 163                 Some(future) => {
 164                     let (prev_graph, prev_work_products) =
 165                         time(self.session(), "blocked while dep-graph loading finishes", || {
 166                             future.open().unwrap_or_else(|e| rustc_incremental::LoadResult::Error {
 167                                 message: format!("could not decode incremental cache: {:?}", e),
 168                             }).open(self.session())
 169                         });
 170                     DepGraph::new(prev_graph, prev_work_products)
 171                 }
 172             })
 173         })
 174     }
 175
 176     pub fn lower_to_hir(&self) -> Result<&Query<(Steal<hir::map::Forest>, ExpansionResult)>> {
 177         self.queries.lower_to_hir.compute(|| {
 178             let expansion_result = self.expansion()?;
 179             let (krate, resolver) = expansion_result.take();
 180             let resolver_ref = &*resolver;
 181             let hir = Steal::new(resolver_ref.as_ref().unwrap().borrow_mut().access(|resolver| {
 182                 passes::lower_to_hir(
 183                     self.session(),
 184                     self.cstore(),
 185                     resolver,
 186                     &*self.dep_graph()?.peek(),
 187                     &krate
 188                 )
 189             })?);
 190             expansion_result.give((krate, Rc::new(None)));
 191             Ok((hir, BoxedResolver::to_expansion_result(resolver)))
 192         })
 193     }
 194
 195     pub fn prepare_outputs(&self) -> Result<&Query<OutputFilenames>> {
 196         self.queries.prepare_outputs.compute(|| {
 197             self.lower_to_hir()?;
 198             let krate = self.expansion()?;
 199             let krate = krate.peek();
 200             let crate_name = self.crate_name()?;
 201             let crate_name = crate_name.peek();
 202             passes::prepare_outputs(self.session(), self, &krate.0, &*crate_name)
 203         })
 204     }
 205
 206     pub fn codegen_channel(&self) -> Result<&Query<(Steal<mpsc::Sender<Box<dyn Any + Send>>>,
 207                                                     Steal<mpsc::Receiver<Box<dyn Any + Send>>>)>> {
 208         self.queries.codegen_channel.compute(|| {
 209             let (tx, rx) = mpsc::channel();
 210             Ok((Steal::new(tx), Steal::new(rx)))
 211         })
 212     }
 213
 214     pub fn global_ctxt(&self) -> Result<&Query<BoxedGlobalCtxt>> {
 215         self.queries.global_ctxt.compute(|| {
 216             let crate_name = self.crate_name()?.peek().clone();
 217             let outputs = self.prepare_outputs()?.peek().clone();
 218             let hir = self.lower_to_hir()?;
 219             let hir = hir.peek();
 220             let (ref hir_forest, ref expansion) = *hir;
 221             let tx = self.codegen_channel()?.peek().0.steal();
 222             Ok(passes::create_global_ctxt(
 223                 self,
 224                 hir_forest.steal(),
 225                 expansion.defs.steal(),
 226                 expansion.resolutions.steal(),
 227                 outputs,
 228                 tx,
 229                 &crate_name))
 230         })
 231     }
 232
 233     pub fn ongoing_codegen(&self) -> Result<&Query<Box<dyn Any>>> {
 234         self.queries.ongoing_codegen.compute(|| {
 235             let rx = self.codegen_channel()?.peek().1.steal();
 236             let outputs = self.prepare_outputs()?;
 237             self.global_ctxt()?.peek_mut().enter(|tcx| {
 238                 tcx.analysis(LOCAL_CRATE).ok();
 239
 240                 // Don't do code generation if there were any errors
 241                 self.session().compile_status()?;
 242
 243                 Ok(passes::start_codegen(
 244                     &***self.codegen_backend(),
 245                     tcx,
 246                     rx,
 247                     &*outputs.peek()
 248                 ))
 249             })
 250         })
 251     }
 252
 253     pub fn link(&self) -> Result<&Query<()>> {
 254         self.queries.link.compute(|| {
 255             let sess = self.session();
 256
 257             let ongoing_codegen = self.ongoing_codegen()?.take();
 258
 259             self.codegen_backend().join_codegen_and_link(
 260                 ongoing_codegen,
 261                 sess,
 262                 &*self.dep_graph()?.peek(),
 263                 &*self.prepare_outputs()?.peek(),
 264             ).map_err(|_| ErrorReported)?;
 265
 266             Ok(())
 267         })
 268     }
 269
 270     pub fn compile(&self) -> Result<()> {
 271         self.prepare_outputs()?;
 272
 273         if self.session().opts.output_types.contains_key(&OutputType::DepInfo)
 274             && self.session().opts.output_types.len() == 1
 275         {
 276             return Ok(())
 277         }
 278
 279         self.global_ctxt()?;
 280
 281         // Drop AST after creating GlobalCtxt to free memory
 282         mem::drop(self.expansion()?.take());
 283
 284         self.ongoing_codegen()?;
 285
 286         // Drop GlobalCtxt after starting codegen to free memory
 287         mem::drop(self.global_ctxt()?.take());
 288
 289         self.link().map(|_| ())
 290     }
 291 }