Auto merge of rust-lang#33783 - michaelwoerister:collector-cleanup-2, r=nikomatsakis

trans::collector: Remove some redundant calls to erase_regions().

r? @Aatch

Author: bors

src/librustc/ty/fold.rs

@@ -99,6 +99,16 @@ pub trait TypeFoldable<'tcx>: fmt::Debug + Clone {
                             TypeFlags::HAS_RE_INFER |
                             TypeFlags::HAS_FREE_REGIONS)
     }
+    fn is_normalized_for_trans(&self) -> bool {
+        !self.has_type_flags(TypeFlags::HAS_RE_EARLY_BOUND |
+                             TypeFlags::HAS_RE_INFER |
+                             TypeFlags::HAS_FREE_REGIONS |
+                             TypeFlags::HAS_TY_INFER |
+                             TypeFlags::HAS_PARAMS |
+                             TypeFlags::HAS_PROJECTION |
+                             TypeFlags::HAS_TY_ERR |
+                             TypeFlags::HAS_SELF)
+    }
     /// Indicates whether this value references only 'global'
     /// types/lifetimes that are the same regardless of what fn we are
     /// in. This is used for caching. Errs on the side of returning

src/librustc_trans/collector.rs

@@ -523,7 +523,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
             let ty = monomorphize::apply_param_substs(self.scx.tcx(),
                                                       self.param_substs,
                                                       &ty);
-            let ty = self.scx.tcx().erase_regions(&ty);
+            assert!(ty.is_normalized_for_trans());
             let ty = glue::get_drop_glue_type(self.scx.tcx(), ty);
             self.output.push(TransItem::DropGlue(DropGlueKind::Ty(ty)));
         }
@@ -859,6 +859,7 @@ fn do_static_trait_method_dispatch<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
                                                        &callee_substs);
 
     let trait_ref = ty::Binder(rcvr_substs.to_trait_ref(tcx, trait_id));
+    let trait_ref = tcx.normalize_associated_type(&trait_ref);
     let vtbl = fulfill_obligation(scx, DUMMY_SP, trait_ref);
 
     // Now that we know which impl is being used, we can dispatch to
@@ -992,11 +993,8 @@ fn create_fn_trans_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let concrete_substs = monomorphize::apply_param_substs(tcx,
                                                            param_substs,
                                                            &fn_substs);
-    let concrete_substs = tcx.erase_regions(&concrete_substs);
-
-    let trans_item =
-        TransItem::Fn(Instance::new(def_id, concrete_substs));
-    return trans_item;
+    assert!(concrete_substs.is_normalized_for_trans());
+    TransItem::Fn(Instance::new(def_id, concrete_substs))
 }
 
 /// Creates a `TransItem` for each method that is referenced by the vtable for
@@ -1034,10 +1032,14 @@ fn create_trans_items_for_vtable_methods<'a, 'tcx>(scx: &SharedCrateContext<'a,
                             } else {
                                 None
                             }
-                        })
-                        .collect::<Vec<_>>();
+                        });
+
+                    output.extend(items);
 
-                    output.extend(items.into_iter());
+                    // Also add the destructor
+                    let dg_type = glue::get_drop_glue_type(scx.tcx(),
+                                                           trait_ref.self_ty());
+                    output.push(TransItem::DropGlue(DropGlueKind::Ty(dg_type)));
                 }
                 _ => { /* */ }
             }
@@ -1234,7 +1236,7 @@ pub enum TransItemState {
 }
 
 pub fn collecting_debug_information(scx: &SharedCrateContext) -> bool {
-    return scx.sess().opts.cg.debug_assertions == Some(true) &&
+    return cfg!(debug_assertions) &&
            scx.sess().opts.debugging_opts.print_trans_items.is_some();
 }
 

src/librustc_trans/glue.rs

@@ -20,7 +20,7 @@ use llvm::{ValueRef, get_param};
 use middle::lang_items::ExchangeFreeFnLangItem;
 use rustc::ty::subst::{Substs};
 use rustc::traits;
-use rustc::ty::{self, Ty, TyCtxt};
+use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};
 use abi::{Abi, FnType};
 use adt;
 use adt::GetDtorType; // for tcx.dtor_type()
@@ -96,10 +96,12 @@ pub fn type_needs_drop<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
 pub fn get_drop_glue_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                     t: Ty<'tcx>) -> Ty<'tcx> {
+    assert!(t.is_normalized_for_trans());
+
     // Even if there is no dtor for t, there might be one deeper down and we
     // might need to pass in the vtable ptr.
     if !type_is_sized(tcx, t) {
-        return tcx.erase_regions(&t);
+        return t;
     }
 
     // FIXME (#22815): note that type_needs_drop conservatively
@@ -123,11 +125,11 @@ pub fn get_drop_glue_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                     // `Box<ZeroSizeType>` does not allocate.
                     tcx.types.i8
                 } else {
-                    tcx.erase_regions(&t)
+                    t
                 }
             })
         }
-        _ => tcx.erase_regions(&t)
+        _ => t
     }
 }
 

src/test/codegen-units/item-collection/instantiation-through-vtable.rs

@@ -40,3 +40,5 @@ fn main() {
     //~ TRANS_ITEM fn instantiation_through_vtable::{{impl}}[0]::bar[0]<u64>
     let _ = &s1 as &Trait;
 }
+
+//~ TRANS_ITEM drop-glue i8

src/test/codegen-units/item-collection/unsizing.rs

@@ -78,3 +78,5 @@ fn main()
     //~ TRANS_ITEM fn unsizing::{{impl}}[3]::foo[0]
     let _wrapper_sized = wrapper_sized as Wrapper<Trait>;
 }
+
+//~ TRANS_ITEM drop-glue i8