rustc: Use reachablility through a query

Turns out this was already set up as a query, just wasn't using it yet!

src/librustc/middle/reachable.rs

@@ -369,10 +369,6 @@ impl<'a, 'tcx: 'a> ItemLikeVisitor<'tcx> for CollectPrivateImplItemsVisitor<'a,
     }
 }
 
-pub fn find_reachable<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Rc<NodeSet> {
-    tcx.reachable_set(LOCAL_CRATE)
-}
-
 fn reachable_set<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, crate_num: CrateNum) -> Rc<NodeSet> {
     debug_assert!(crate_num == LOCAL_CRATE);
 

src/librustc/ty/mod.rs

@@ -121,7 +121,6 @@ mod sty;
 #[derive(Clone)]
 pub struct CrateAnalysis {
     pub access_levels: Rc<AccessLevels>,
-    pub reachable: Rc<NodeSet>,
     pub name: String,
     pub glob_map: Option<hir::GlobMap>,
 }

src/librustc_driver/driver.rs

@@ -28,7 +28,6 @@ use rustc::mir::transform::{MIR_CONST, MIR_VALIDATED, MIR_OPTIMIZED, Passes};
 use rustc::ty::{self, TyCtxt, Resolutions, GlobalArenas};
 use rustc::traits;
 use rustc::util::common::{ErrorReported, time};
-use rustc::util::nodemap::NodeSet;
 use rustc_allocator as allocator;
 use rustc_borrowck as borrowck;
 use rustc_incremental::{self, IncrementalHashesMap};
@@ -243,7 +242,7 @@ pub fn compile_input(sess: &Session,
                 tcx.print_debug_stats();
             }
 
-            let trans = phase_4_translate_to_llvm(tcx, analysis, incremental_hashes_map,
+            let trans = phase_4_translate_to_llvm(tcx, incremental_hashes_map,
                                                   &outputs);
 
             if log_enabled!(::log::LogLevel::Info) {
@@ -885,7 +884,6 @@ pub fn phase_2_configure_and_expand<F>(sess: &Session,
         defs: resolver.definitions,
         analysis: ty::CrateAnalysis {
             access_levels: Rc::new(AccessLevels::default()),
-            reachable: Rc::new(NodeSet()),
             name: crate_name.to_string(),
             glob_map: if resolver.make_glob_map { Some(resolver.glob_map) } else { None },
         },
@@ -1103,11 +1101,6 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
             return Ok(f(tcx, analysis, incremental_hashes_map, sess.compile_status()));
         }
 
-        analysis.reachable =
-            time(time_passes,
-                 "reachability checking",
-                 || reachable::find_reachable(tcx));
-
         time(time_passes, "death checking", || middle::dead::check_crate(tcx));
 
         time(time_passes, "unused lib feature checking", || {
@@ -1123,7 +1116,6 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
 /// Run the translation phase to LLVM, after which the AST and analysis can
 /// be discarded.
 pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                                           analysis: ty::CrateAnalysis,
                                            incremental_hashes_map: IncrementalHashesMap,
                                            output_filenames: &OutputFilenames)
                                            -> write::OngoingCrateTranslation {
@@ -1136,7 +1128,7 @@ pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let translation =
         time(time_passes,
              "translation",
-             move || trans::trans_crate(tcx, analysis, incremental_hashes_map, output_filenames));
+             move || trans::trans_crate(tcx, incremental_hashes_map, output_filenames));
 
     if tcx.sess.profile_queries() {
         profile::dump("profile_queries".to_string())

src/librustc_trans/base.rs

@@ -886,8 +886,8 @@ fn iter_globals(llmod: llvm::ModuleRef) -> ValueIter {
 ///
 /// This list is later used by linkers to determine the set of symbols needed to
 /// be exposed from a dynamic library and it's also encoded into the metadata.
-pub fn find_exported_symbols(tcx: TyCtxt, reachable: &NodeSet) -> NodeSet {
-    reachable.iter().cloned().filter(|&id| {
+pub fn find_exported_symbols(tcx: TyCtxt) -> NodeSet {
+    tcx.reachable_set(LOCAL_CRATE).iter().cloned().filter(|&id| {
         // Next, we want to ignore some FFI functions that are not exposed from
         // this crate. Reachable FFI functions can be lumped into two
         // categories:
@@ -929,7 +929,6 @@ pub fn find_exported_symbols(tcx: TyCtxt, reachable: &NodeSet) -> NodeSet {
 }
 
 pub fn trans_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                             analysis: ty::CrateAnalysis,
                              incremental_hashes_map: IncrementalHashesMap,
                              output_filenames: &OutputFilenames)
                              -> OngoingCrateTranslation {
@@ -940,10 +939,9 @@ pub fn trans_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     // `TransCrate`, you need to be careful to register "reads" of the
     // particular items that will be processed.
     let krate = tcx.hir.krate();
-    let ty::CrateAnalysis { reachable, .. } = analysis;
     let check_overflow = tcx.sess.overflow_checks();
     let link_meta = link::build_link_meta(&incremental_hashes_map);
-    let exported_symbol_node_ids = find_exported_symbols(tcx, &reachable);
+    let exported_symbol_node_ids = find_exported_symbols(tcx);
 
     let shared_ccx = SharedCrateContext::new(tcx,
                                              check_overflow,