auto merge of #11535 : thestinger/rust/header, r=alexcrichton

Unique pointers and vectors currently contain a reference counting
header when containing a managed pointer.

This `{ ref_count, type_desc, prev, next }` header is not necessary and
not a sensible foundation for tracing. It adds needless complexity to
library code and is responsible for breakage in places where the branch
 has been left out.

The `borrow_offset` field can now be removed from `TyDesc` along with
the associated handling in the compiler.

Closes #9510
Closes #11533

24 files changed, 157 insertions, 199 deletions

diff --git a/src/librustc/back/abi.rs b/src/librustc/back/abi.rs
index 945ee645414..8f639a5e499 100644
--- a/src/librustc/back/abi.rs
+++ b/src/librustc/back/abi.rs
@@ -45,9 +45,8 @@ pub static tydesc_field_align: uint = 1u;
 pub static tydesc_field_take_glue: uint = 2u;
 pub static tydesc_field_drop_glue: uint = 3u;
 pub static tydesc_field_visit_glue: uint = 4u;
-pub static tydesc_field_borrow_offset: uint = 5u;
-pub static tydesc_field_name_offset: uint = 6u;
-pub static n_tydesc_fields: uint = 7u;
+pub static tydesc_field_name_offset: uint = 5u;
+pub static n_tydesc_fields: uint = 6u;
 
 // The two halves of a closure: code and environment.
 pub static fn_field_code: uint = 0u;
diff --git a/src/librustc/middle/trans/_match.rs b/src/librustc/middle/trans/_match.rs
index aa2bd656b90..a7924946ed1 100644
--- a/src/librustc/middle/trans/_match.rs
+++ b/src/librustc/middle/trans/_match.rs
@@ -1584,14 +1584,9 @@ fn compile_submatch_continue<'r,
     }
 
     if any_uniq_pat(m, col) {
-        let pat_ty = node_id_type(bcx, pat_id);
         let llbox = Load(bcx, val);
-        let unboxed = match ty::get(pat_ty).sty {
-            ty::ty_uniq(..) if !ty::type_contents(bcx.tcx(), pat_ty).owns_managed() => llbox,
-            _ => GEPi(bcx, llbox, [0u, abi::box_field_body])
-        };
         compile_submatch(bcx, enter_uniq(bcx, dm, m, col, val),
-                         vec::append(~[unboxed], vals_left), chk);
+                         vec::append(~[llbox], vals_left), chk);
         return;
     }
 
@@ -2231,13 +2226,8 @@ fn bind_irrefutable_pat<'a>(
             }
         }
         ast::PatUniq(inner) => {
-            let pat_ty = node_id_type(bcx, pat.id);
             let llbox = Load(bcx, val);
-            let unboxed = match ty::get(pat_ty).sty {
-                ty::ty_uniq(..) if !ty::type_contents(bcx.tcx(), pat_ty).owns_managed() => llbox,
-                    _ => GEPi(bcx, llbox, [0u, abi::box_field_body])
-            };
-            bcx = bind_irrefutable_pat(bcx, inner, unboxed, binding_mode);
+            bcx = bind_irrefutable_pat(bcx, inner, llbox, binding_mode);
         }
         ast::PatRegion(inner) => {
             let loaded_val = Load(bcx, val);
diff --git a/src/librustc/middle/trans/base.rs b/src/librustc/middle/trans/base.rs
index a65712bd30a..46f647cc1a6 100644
--- a/src/librustc/middle/trans/base.rs
+++ b/src/librustc/middle/trans/base.rs
@@ -368,7 +368,7 @@ pub fn malloc_raw_dyn<'a>(
     } else {
         // we treat ~fn, @fn and @[] as @ here, which isn't ideal
         let langcall = match heap {
-            heap_managed | heap_managed_unique => {
+            heap_managed => {
                 require_alloc_fn(bcx, t, MallocFnLangItem)
             }
             heap_exchange_closure => {
@@ -392,9 +392,7 @@ pub fn malloc_raw_dyn<'a>(
             langcall,
             [tydesc, size],
             None);
-        let r = rslt(r.bcx, PointerCast(r.bcx, r.val, llty));
-        maybe_set_managed_unique_rc(r.bcx, r.val, heap);
-        r
+        rslt(r.bcx, PointerCast(r.bcx, r.val, llty))
     }
 }
 
@@ -441,27 +439,6 @@ pub fn malloc_general<'a>(bcx: &'a Block, t: ty::t, heap: heap)
     malloc_general_dyn(bcx, t, heap, llsize_of(bcx.ccx(), ty))
 }
 
-pub fn heap_for_unique(bcx: &Block, t: ty::t) -> heap {
-    if ty::type_contents(bcx.tcx(), t).owns_managed() {
-        heap_managed_unique
-    } else {
-        heap_exchange
-    }
-}
-
-pub fn maybe_set_managed_unique_rc(bcx: &Block, bx: ValueRef, heap: heap) {
-    assert!(heap != heap_exchange);
-    if heap == heap_managed_unique {
-        // In cases where we are looking at a unique-typed allocation in the
-        // managed heap (thus have refcount 1 from the managed allocator),
-        // such as a ~(@foo) or such. These need to have their refcount forced
-        // to -2 so the annihilator ignores them.
-        let rc = GEPi(bcx, bx, [0u, abi::box_field_refcnt]);
-        let rc_val = C_int(bcx.ccx(), -2);
-        Store(bcx, rc_val, rc);
-    }
-}
-
 // Type descriptor and type glue stuff
 
 pub fn get_tydesc_simple(ccx: &CrateContext, t: ty::t) -> ValueRef {
diff --git a/src/librustc/middle/trans/closure.rs b/src/librustc/middle/trans/closure.rs
index d371637e1a7..f3d061f70b1 100644
--- a/src/librustc/middle/trans/closure.rs
+++ b/src/librustc/middle/trans/closure.rs
@@ -150,14 +150,6 @@ pub fn mk_closure_tys(tcx: ty::ctxt,
     return cdata_ty;
 }
 
-fn heap_for_unique_closure(bcx: &Block, t: ty::t) -> heap {
-    if ty::type_contents(bcx.tcx(), t).owns_managed() {
-        heap_managed_unique
-    } else {
-        heap_exchange_closure
-    }
-}
-
 pub fn allocate_cbox<'a>(
                      bcx: &'a Block<'a>,
                      sigil: ast::Sigil,
@@ -173,7 +165,7 @@ pub fn allocate_cbox<'a>(
             tcx.sess.bug("trying to trans allocation of @fn")
         }
         ast::OwnedSigil => {
-            malloc_raw(bcx, cdata_ty, heap_for_unique_closure(bcx, cdata_ty))
+            malloc_raw(bcx, cdata_ty, heap_exchange_closure)
         }
         ast::BorrowedSigil => {
             let cbox_ty = tuplify_box_ty(tcx, cdata_ty);
diff --git a/src/librustc/middle/trans/common.rs b/src/librustc/middle/trans/common.rs
index 7f6ab2dd9d1..f98fec7cbef 100644
--- a/src/librustc/middle/trans/common.rs
+++ b/src/librustc/middle/trans/common.rs
@@ -90,7 +90,6 @@ pub struct tydesc_info {
     tydesc: ValueRef,
     size: ValueRef,
     align: ValueRef,
-    borrow_offset: ValueRef,
     name: ValueRef,
     take_glue: Cell<Option<ValueRef>>,
     drop_glue: Cell<Option<ValueRef>>,
@@ -316,7 +315,6 @@ pub fn warn_not_to_commit(ccx: &CrateContext, msg: &str) {
 #[deriving(Eq)]
 pub enum heap {
     heap_managed,
-    heap_managed_unique,
     heap_exchange,
     heap_exchange_closure
 }
@@ -498,7 +496,7 @@ pub fn add_clean_temp_mem_in_scope_(bcx: &Block, scope_id: Option<ast::NodeId>,
 
 pub fn add_clean_free(cx: &Block, ptr: ValueRef, heap: heap) {
     let free_fn = match heap {
-        heap_managed | heap_managed_unique => {
+        heap_managed => {
             @GCHeapFreeingCleanupFunction {
                 ptr: ptr,
             } as @CleanupFunction
diff --git a/src/librustc/middle/trans/datum.rs b/src/librustc/middle/trans/datum.rs
index 35414162a27..c2591beac4a 100644
--- a/src/librustc/middle/trans/datum.rs
+++ b/src/librustc/middle/trans/datum.rs
@@ -570,11 +570,6 @@ impl Datum {
         let (content_ty, header) = match ty::get(self.ty).sty {
             ty::ty_box(typ) => (typ, true),
             ty::ty_uniq(typ) => (typ, false),
-            ty::ty_vec(_, ty::vstore_uniq) | ty::ty_str(ty::vstore_uniq) => {
-                let unit_ty = ty::sequence_element_type(bcx.tcx(), self.ty);
-                let unboxed_vec_ty = ty::mk_mut_unboxed_vec(bcx.tcx(), unit_ty);
-                (unboxed_vec_ty, true)
-            }
             _ => {
                 bcx.tcx().sess.bug(format!(
                     "box_body() invoked on non-box type {}",
@@ -582,7 +577,7 @@ impl Datum {
             }
         };
 
-        if !header && !ty::type_contents(bcx.tcx(), content_ty).owns_managed() {
+        if !header {
             let ptr = self.to_value_llval(bcx);
             let ty = type_of::type_of(bcx.ccx(), content_ty);
             let body = PointerCast(bcx, ptr, ty.ptr_to());
diff --git a/src/librustc/middle/trans/debuginfo.rs b/src/librustc/middle/trans/debuginfo.rs
index 97bcf92fcc9..4e8b3c78dc8 100644
--- a/src/librustc/middle/trans/debuginfo.rs
+++ b/src/librustc/middle/trans/debuginfo.rs
@@ -2147,10 +2147,6 @@ fn type_metadata(cx: &CrateContext,
                 ty::vstore_fixed(len) => {
                     fixed_vec_metadata(cx, mt.ty, len, usage_site_span)
                 }
-                ty::vstore_uniq if ty::type_contents(cx.tcx, mt.ty).owns_managed() => {
-                    let boxed_vec_metadata = boxed_vec_metadata(cx, mt.ty, usage_site_span);
-                    pointer_type_metadata(cx, t, boxed_vec_metadata)
-                }
                 ty::vstore_uniq => {
                     let vec_metadata = vec_metadata(cx, mt.ty, usage_site_span);
                     pointer_type_metadata(cx, t, vec_metadata)
@@ -2165,12 +2161,8 @@ fn type_metadata(cx: &CrateContext,
             }
         },
         ty::ty_uniq(typ) => {
-            if ty::type_contents(cx.tcx, typ).owns_managed() {
-                create_pointer_to_box_metadata(cx, t, typ)
-            } else {
-                let pointee = type_metadata(cx, typ, usage_site_span);
-                pointer_type_metadata(cx, t, pointee)
-            }
+            let pointee = type_metadata(cx, typ, usage_site_span);
+            pointer_type_metadata(cx, t, pointee)
         }
         ty::ty_ptr(ref mt) | ty::ty_rptr(_, ref mt) => {
             let pointee = type_metadata(cx, mt.ty, usage_site_span);
diff --git a/src/librustc/middle/trans/expr.rs b/src/librustc/middle/trans/expr.rs
index 8d3b953af18..72fc3e80228 100644
--- a/src/librustc/middle/trans/expr.rs
+++ b/src/librustc/middle/trans/expr.rs
@@ -398,29 +398,7 @@ pub fn trans_to_datum<'a>(bcx: &'a Block<'a>, expr: &ast::Expr)
                                                      autoderefs));
                 derefd_datum.to_rptr(bcx).to_value_llval(bcx)
             }
-            ty::UniqTraitStore(..) => {
-                // For a ~T box, there may or may not be a header,
-                // depending on whether the type T references managed
-                // boxes. However, since we do not *know* the type T
-                // for objects, this presents a hurdle. Our solution is
-                // to load the "borrow offset" from the type descriptor;
-                // this value will either be 0 or sizeof(BoxHeader), depending
-                // on the type T.
-                let llopaque =
-                    PointerCast(bcx, source_data, Type::opaque().ptr_to());
-                let lltydesc_ptr_ptr =
-                    PointerCast(bcx, vtable,
-                                bcx.ccx().tydesc_type.ptr_to().ptr_to());
-                let lltydesc_ptr =
-                    Load(bcx, lltydesc_ptr_ptr);
-                let borrow_offset_ptr =
-                    GEPi(bcx, lltydesc_ptr,
-                         [0, abi::tydesc_field_borrow_offset]);
-                let borrow_offset =
-                    Load(bcx, borrow_offset_ptr);
-                InBoundsGEP(bcx, llopaque, [borrow_offset])
-            }
-            ty::RegionTraitStore(..) => {
+            ty::UniqTraitStore(..) | ty::RegionTraitStore(..) => {
                 source_data
             }
         };
@@ -608,8 +586,7 @@ fn trans_rvalue_datum_unadjusted<'a>(bcx: &'a Block<'a>, expr: &ast::Expr)
                                                       expr, contents);
         }
         ast::ExprVstore(contents, ast::ExprVstoreUniq) => {
-            let heap = heap_for_unique(bcx, expr_ty(bcx, contents));
-            return tvec::trans_uniq_or_managed_vstore(bcx, heap,
+            return tvec::trans_uniq_or_managed_vstore(bcx, heap_exchange,
                                                       expr, contents);
         }
         ast::ExprBox(_, contents) => {
@@ -617,7 +594,7 @@ fn trans_rvalue_datum_unadjusted<'a>(bcx: &'a Block<'a>, expr: &ast::Expr)
             // `trans_rvalue_dps_unadjusted`.)
             let box_ty = expr_ty(bcx, expr);
             let contents_ty = expr_ty(bcx, contents);
-            let heap = heap_for_unique(bcx, contents_ty);
+            let heap = heap_exchange;
             return trans_boxed_expr(bcx, box_ty, contents, contents_ty, heap)
         }
         ast::ExprLit(lit) => {
@@ -1461,8 +1438,7 @@ fn trans_unary_datum<'a>(
             trans_boxed_expr(bcx, un_ty, sub_expr, sub_ty, heap_managed)
         }
         ast::UnUniq => {
-            let heap  = heap_for_unique(bcx, un_ty);
-            trans_boxed_expr(bcx, un_ty, sub_expr, sub_ty, heap)
+            trans_boxed_expr(bcx, un_ty, sub_expr, sub_ty, heap_exchange)
         }
         ast::UnDeref => {
             bcx.sess().bug("deref expressions should have been \
diff --git a/src/librustc/middle/trans/glue.rs b/src/librustc/middle/trans/glue.rs
index f4c007f018b..9b3243fa3ef 100644
--- a/src/librustc/middle/trans/glue.rs
+++ b/src/librustc/middle/trans/glue.rs
@@ -303,11 +303,7 @@ pub fn make_free_glue<'a>(bcx: &'a Block<'a>, v: ValueRef, t: ty::t)
         with_cond(bcx, not_null, |bcx| {
             let body_datum = box_datum.box_body(bcx);
             let bcx = drop_ty(bcx, body_datum.to_ref_llval(bcx), body_datum.ty);
-            if ty::type_contents(bcx.tcx(), t).owns_managed() {
-                trans_free(bcx, box_datum.val)
-            } else {
-                trans_exchange_free(bcx, box_datum.val)
-            }
+            trans_exchange_free(bcx, box_datum.val)
         })
       }
       ty::ty_vec(_, ty::vstore_uniq) | ty::ty_str(ty::vstore_uniq) |
@@ -550,18 +546,6 @@ pub fn declare_tydesc(ccx: &CrateContext, t: ty::t) -> @tydesc_info {
                  ppaux::ty_to_str(ccx.tcx, t));
     }
 
-    let has_header = match ty::get(t).sty {
-        ty::ty_box(..) => true,
-        ty::ty_uniq(..) => ty::type_contents(ccx.tcx, t).owns_managed(),
-        _ => false
-    };
-
-    let borrow_offset = if has_header {
-        ccx.offsetof_gep(llty, [0u, abi::box_field_body])
-    } else {
-        C_uint(ccx, 0)
-    };
-
     let llsize = llsize_of(ccx, llty);
     let llalign = llalign_of(ccx, llty);
     let name = mangle_internal_name_by_type_and_seq(ccx, t, "tydesc").to_managed();
@@ -580,7 +564,6 @@ pub fn declare_tydesc(ccx: &CrateContext, t: ty::t) -> @tydesc_info {
         tydesc: gvar,
         size: llsize,
         align: llalign,
-        borrow_offset: borrow_offset,
         name: ty_name,
         take_glue: Cell::new(None),
         drop_glue: Cell::new(None),
@@ -690,15 +673,12 @@ pub fn emit_tydescs(ccx: &CrateContext) {
               }
             };
 
-        debug!("ti.borrow_offset: {}", ccx.tn.val_to_str(ti.borrow_offset));
-
         let tydesc = C_named_struct(ccx.tydesc_type,
                                     [ti.size, // size
                                      ti.align, // align
                                      take_glue, // take_glue
                                      drop_glue, // drop_glue
                                      visit_glue, // visit_glue
-                                     ti.borrow_offset, // borrow_offset
                                      ti.name]); // name
 
         unsafe {
diff --git a/src/librustc/middle/trans/reflect.rs b/src/librustc/middle/trans/reflect.rs
index e8d9015e860..2a8c23a6c32 100644
--- a/src/librustc/middle/trans/reflect.rs
+++ b/src/librustc/middle/trans/reflect.rs
@@ -184,11 +184,7 @@ impl<'a> Reflector<'a> {
           ty::ty_vec(ref mt, vst) => {
               let (name, extra) = self.vstore_name_and_extra(t, vst);
               let extra = extra + self.c_mt(mt);
-              if "uniq" == name && ty::type_contents(bcx.tcx(), t).owns_managed() {
-                  self.visit("evec_uniq_managed", extra)
-              } else {
-                  self.visit(~"evec_" + name, extra)
-              }
+              self.visit(~"evec_" + name, extra)
           }
           // Should remove mt from box and uniq.
           ty::ty_box(typ) => {
@@ -203,11 +199,7 @@ impl<'a> Reflector<'a> {
                   ty: typ,
                   mutbl: ast::MutImmutable,
               });
-              if ty::type_contents(bcx.tcx(), t).owns_managed() {
-                  self.visit("uniq_managed", extra)
-              } else {
-                  self.visit("uniq", extra)
-              }
+              self.visit("uniq", extra)
           }
           ty::ty_ptr(ref mt) => {
               let extra = self.c_mt(mt);
diff --git a/src/librustc/middle/trans/tvec.rs b/src/librustc/middle/trans/tvec.rs
index 9819f34c6f1..100f28af97d 100644
--- a/src/librustc/middle/trans/tvec.rs
+++ b/src/librustc/middle/trans/tvec.rs
@@ -64,7 +64,14 @@ pub fn get_alloc(bcx: &Block, vptr: ValueRef) -> ValueRef {
 }
 
 pub fn get_bodyptr(bcx: &Block, vptr: ValueRef, t: ty::t) -> ValueRef {
-    if ty::type_contents(bcx.tcx(), t).owns_managed() {
+    let vt = vec_types(bcx, t);
+
+    let managed = match ty::get(vt.vec_ty).sty {
+      ty::ty_str(ty::vstore_box) | ty::ty_vec(_, ty::vstore_box) => true,
+      _ => false
+    };
+
+    if managed {
         GEPi(bcx, vptr, [0u, abi::box_field_body])
     } else {
         vptr
@@ -106,7 +113,6 @@ pub fn alloc_raw<'a>(
             base::malloc_general_dyn(bcx, vecbodyty, heap, vecsize);
         Store(bcx, fill, GEPi(bcx, body, [0u, abi::vec_elt_fill]));
         Store(bcx, alloc, GEPi(bcx, body, [0u, abi::vec_elt_alloc]));
-        base::maybe_set_managed_unique_rc(bcx, bx, heap);
         return rslt(bcx, bx);
     }
 }
@@ -117,7 +123,7 @@ pub fn alloc_uniq_raw<'a>(
                       fill: ValueRef,
                       alloc: ValueRef)
                       -> Result<'a> {
-    alloc_raw(bcx, unit_ty, fill, alloc, base::heap_for_unique(bcx, unit_ty))
+    alloc_raw(bcx, unit_ty, fill, alloc, heap_exchange)
 }
 
 pub fn alloc_vec<'a>(
@@ -350,7 +356,7 @@ pub fn trans_uniq_or_managed_vstore<'a>(
             }
         }
         heap_exchange_closure => fail!("vectors use exchange_alloc"),
-        heap_managed | heap_managed_unique => {}
+        heap_managed => {}
     }
 
     let vt = vec_types_from_expr(bcx, vstore_expr);
diff --git a/src/librustc/middle/trans/type_.rs b/src/librustc/middle/trans/type_.rs
index d4ba4a76f81..833a7848ad3 100644
--- a/src/librustc/middle/trans/type_.rs
+++ b/src/librustc/middle/trans/type_.rs
@@ -220,7 +220,6 @@ impl Type {
                      glue_fn_ty, // take
                      glue_fn_ty, // drop
                      glue_fn_ty, // visit
-                     int_ty, // borrow_offset
                      Type::struct_([Type::i8p(), Type::int(arch)], false)]; // name
         tydesc.set_struct_body(elems, false);
 
@@ -269,10 +268,6 @@ impl Type {
         Type::smart_ptr(ctx, &Type::opaque())
     }
 
-    pub fn unique(ctx: &CrateContext, ty: &Type) -> Type {
-        Type::smart_ptr(ctx, ty)
-    }
-
     pub fn opaque_cbox_ptr(cx: &CrateContext) -> Type {
         Type::opaque_box(cx).ptr_to()
     }
@@ -281,7 +276,7 @@ impl Type {
         let tydesc_ptr = ctx.tydesc_type.ptr_to();
         let box_ty = match store {
             ty::BoxTraitStore => Type::opaque_box(ctx),
-            ty::UniqTraitStore => Type::unique(ctx, &Type::i8()),
+            ty::UniqTraitStore => Type::i8(),
             ty::RegionTraitStore(..) => Type::i8()
         };
         Type::struct_([tydesc_ptr, box_ty.ptr_to()], false)
diff --git a/src/librustc/middle/trans/type_of.rs b/src/librustc/middle/trans/type_of.rs
index 2fc35f379ba..ae96f43b07d 100644
--- a/src/librustc/middle/trans/type_of.rs
+++ b/src/librustc/middle/trans/type_of.rs
@@ -245,21 +245,11 @@ pub fn type_of(cx: &CrateContext, t: ty::t) -> Type {
           Type::smart_ptr(cx, &ty).ptr_to()
       }
       ty::ty_uniq(typ) => {
-          let ty = type_of(cx, typ);
-          if ty::type_contents(cx.tcx, typ).owns_managed() {
-              Type::unique(cx, &ty).ptr_to()
-          } else {
-              ty.ptr_to()
-          }
+          type_of(cx, typ).ptr_to()
       }
       ty::ty_vec(ref mt, ty::vstore_uniq) => {
           let ty = type_of(cx, mt.ty);
-          let ty = Type::vec(cx.sess.targ_cfg.arch, &ty);
-          if ty::type_contents(cx.tcx, mt.ty).owns_managed() {
-              Type::unique(cx, &ty).ptr_to()
-          } else {
-              ty.ptr_to()
-          }
+          Type::vec(cx.sess.targ_cfg.arch, &ty).ptr_to()
       }
       ty::ty_unboxed_vec(ref mt) => {
           let ty = type_of(cx, mt.ty);
diff --git a/src/libstd/rc.rs b/src/libstd/rc.rs
index 9947d8822ae..48e796f0f4a 100644
--- a/src/libstd/rc.rs
+++ b/src/libstd/rc.rs
@@ -230,4 +230,12 @@ mod tests {
         drop(x);
         assert!(y.upgrade().is_none());
     }
+
+    #[test]
+    fn gc_inside() {
+        // see issue #11532
+        use gc::Gc;
+        let a = Rc::new(RefCell::new(Gc::new(1)));
+        assert!(a.borrow().try_borrow_mut().is_some());
+    }
 }
diff --git a/src/libstd/reflect.rs b/src/libstd/reflect.rs
index 8a3e60eb3e2..c4a5561a7aa 100644
--- a/src/libstd/reflect.rs
+++ b/src/libstd/reflect.rs
@@ -227,6 +227,7 @@ impl<V:TyVisitor + MovePtr> TyVisitor for MovePtrAdaptor<V> {
         true
     }
 
+    #[cfg(stage0)]
     fn visit_uniq_managed(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
         self.align_to::<~u8>();
         if ! self.inner.visit_uniq_managed(mtbl, inner) { return false; }
@@ -275,6 +276,7 @@ impl<V:TyVisitor + MovePtr> TyVisitor for MovePtrAdaptor<V> {
         true
     }
 
+    #[cfg(stage0)]
     fn visit_evec_uniq_managed(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
         self.align_to::<~[@u8]>();
         if ! self.inner.visit_evec_uniq_managed(mtbl, inner) { return false; }
diff --git a/src/libstd/repr.rs b/src/libstd/repr.rs
index e0f96365edd..8539717544d 100644
--- a/src/libstd/repr.rs
+++ b/src/libstd/repr.rs
@@ -310,6 +310,7 @@ impl<'a> TyVisitor for ReprVisitor<'a> {
         })
     }
 
+    #[cfg(stage0)]
     fn visit_uniq_managed(&mut self, _mtbl: uint, inner: *TyDesc) -> bool {
         self.writer.write(['~' as u8]);
         self.get::<&raw::Box<()>>(|this, b| {
@@ -358,6 +359,7 @@ impl<'a> TyVisitor for ReprVisitor<'a> {
         })
     }
 
+    #[cfg(stage0)]
     fn visit_evec_uniq_managed(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
         self.get::<&raw::Box<raw::Vec<()>>>(|this, b| {
             this.writer.write(['~' as u8]);
diff --git a/src/libstd/unstable/intrinsics.rs b/src/libstd/unstable/intrinsics.rs
index acd1cfcf901..18a1790cd9b 100644
--- a/src/libstd/unstable/intrinsics.rs
+++ b/src/libstd/unstable/intrinsics.rs
@@ -98,13 +98,6 @@ pub struct TyDesc {
     // Called by reflection visitor to visit a value of type `T`
     visit_glue: GlueFn,
 
-    // If T represents a box pointer (`@U` or `~U`), then
-    // `borrow_offset` is the amount that the pointer must be adjusted
-    // to find the payload.  This is always derivable from the type
-    // `U`, but in the case of `@Trait` or `~Trait` objects, the type
-    // `U` is unknown.
-    borrow_offset: uint,
-
     // Name corresponding to the type
     name: &'static str
 }
@@ -146,6 +139,7 @@ pub trait TyVisitor {
 
     fn visit_box(&mut self, mtbl: uint, inner: *TyDesc) -> bool;
     fn visit_uniq(&mut self, mtbl: uint, inner: *TyDesc) -> bool;
+    #[cfg(stage0)]
     fn visit_uniq_managed(&mut self, mtbl: uint, inner: *TyDesc) -> bool;
     fn visit_ptr(&mut self, mtbl: uint, inner: *TyDesc) -> bool;
     fn visit_rptr(&mut self, mtbl: uint, inner: *TyDesc) -> bool;
@@ -154,6 +148,7 @@ pub trait TyVisitor {
     fn visit_unboxed_vec(&mut self, mtbl: uint, inner: *TyDesc) -> bool;
     fn visit_evec_box(&mut self, mtbl: uint, inner: *TyDesc) -> bool;
     fn visit_evec_uniq(&mut self, mtbl: uint, inner: *TyDesc) -> bool;
+    #[cfg(stage0)]
     fn visit_evec_uniq_managed(&mut self, mtbl: uint, inner: *TyDesc) -> bool;
     fn visit_evec_slice(&mut self, mtbl: uint, inner: *TyDesc) -> bool;
     fn visit_evec_fixed(&mut self, n: uint, sz: uint, align: uint,
diff --git a/src/libstd/unstable/raw.rs b/src/libstd/unstable/raw.rs
index 64a9a7c672a..8aee26c24b2 100644
--- a/src/libstd/unstable/raw.rs
+++ b/src/libstd/unstable/raw.rs
@@ -57,6 +57,7 @@ impl<'a, T> Repr<Slice<T>> for &'a [T] {}
 impl<'a> Repr<Slice<u8>> for &'a str {}
 impl<T> Repr<*Box<T>> for @T {}
 impl<T> Repr<*Box<Vec<T>>> for @[T] {}
+impl<T> Repr<*Vec<T>> for ~[T] {}
 impl Repr<*String> for ~str {}
 impl Repr<*Box<String>> for @str {}
 
diff --git a/src/libstd/vec.rs b/src/libstd/vec.rs
index 61e78b68adc..797582e57f4 100644
--- a/src/libstd/vec.rs
+++ b/src/libstd/vec.rs
@@ -116,14 +116,18 @@ use ptr::to_unsafe_ptr;
 use ptr;
 use ptr::RawPtr;
 use rt::global_heap::{malloc_raw, realloc_raw, exchange_free};
+#[cfg(stage0)]
 use rt::local_heap::local_free;
 use mem;
 use mem::size_of;
 use uint;
 use unstable::finally::Finally;
 use unstable::intrinsics;
+#[cfg(stage0)]
 use unstable::intrinsics::{get_tydesc, owns_managed};
-use unstable::raw::{Box, Repr, Slice, Vec};
+use unstable::raw::{Repr, Slice, Vec};
+#[cfg(stage0)]
+use unstable::raw::Box;
 use util;
 
 /**
@@ -178,6 +182,7 @@ pub fn from_elem<T:Clone>(n_elts: uint, t: T) -> ~[T] {
 
 /// Creates a new vector with a capacity of `capacity`
 #[inline]
+#[cfg(stage0)]
 pub fn with_capacity<T>(capacity: uint) -> ~[T] {
     unsafe {
         if owns_managed::<T>() {
@@ -198,6 +203,23 @@ pub fn with_capacity<T>(capacity: uint) -> ~[T] {
     }
 }
 
+/// Creates a new vector with a capacity of `capacity`
+#[inline]
+#[cfg(not(stage0))]
+pub fn with_capacity<T>(capacity: uint) -> ~[T] {
+    unsafe {
+        let alloc = capacity * mem::nonzero_size_of::<T>();
+        let size = alloc + mem::size_of::<Vec<()>>();
+        if alloc / mem::nonzero_size_of::<T>() != capacity || size < alloc {
+            fail!("vector size is too large: {}", capacity);
+        }
+        let ptr = malloc_raw(size) as *mut Vec<()>;
+        (*ptr).alloc = alloc;
+        (*ptr).fill = 0;
+        cast::transmute(ptr)
+    }
+}
+
 /**
  * Builds a vector by calling a provided function with an argument
  * function that pushes an element to the back of a vector.
@@ -784,7 +806,7 @@ impl<T> Container for ~[T] {
     /// Returns the length of a vector
     #[inline]
     fn len(&self) -> uint {
-        self.repr().len
+        self.as_slice().len()
     }
 }
 
@@ -1481,6 +1503,7 @@ impl<T> OwnedVector<T> for ~[T] {
         self.move_iter().invert()
     }
 
+    #[cfg(stage0)]
     fn reserve(&mut self, n: uint) {
         // Only make the (slow) call into the runtime if we have to
         if self.capacity() < n {
@@ -1504,6 +1527,24 @@ impl<T> OwnedVector<T> for ~[T] {
         }
     }
 
+    #[cfg(not(stage0))]
+    fn reserve(&mut self, n: uint) {
+        // Only make the (slow) call into the runtime if we have to
+        if self.capacity() < n {
+            unsafe {
+                let ptr: *mut *mut Vec<()> = cast::transmute(self);
+                let alloc = n * mem::nonzero_size_of::<T>();
+                let size = alloc + mem::size_of::<Vec<()>>();
+                if alloc / mem::nonzero_size_of::<T>() != n || size < alloc {
+                    fail!("vector size is too large: {}", n);
+                }
+                *ptr = realloc_raw(*ptr as *mut c_void, size)
+                       as *mut Vec<()>;
+                (**ptr).alloc = alloc;
+            }
+        }
+    }
+
     #[inline]
     fn reserve_at_least(&mut self, n: uint) {
         self.reserve(uint::next_power_of_two_opt(n).unwrap_or(n));
@@ -1520,6 +1561,7 @@ impl<T> OwnedVector<T> for ~[T] {
     }
 
     #[inline]
+    #[cfg(stage0)]
     fn capacity(&self) -> uint {
         unsafe {
             if owns_managed::<T>() {
@@ -1532,6 +1574,15 @@ impl<T> OwnedVector<T> for ~[T] {
         }
     }
 
+    #[inline]
+    #[cfg(not(stage0))]
+    fn capacity(&self) -> uint {
+        unsafe {
+            let repr: **Vec<()> = cast::transmute(self);
+            (**repr).alloc / mem::nonzero_size_of::<T>()
+        }
+    }
+
     fn shrink_to_fit(&mut self) {
         unsafe {
             let ptr: *mut *mut Vec<()> = cast::transmute(self);
@@ -1543,6 +1594,7 @@ impl<T> OwnedVector<T> for ~[T] {
     }
 
     #[inline]
+    #[cfg(stage0)]
     fn push(&mut self, t: T) {
         unsafe {
             if owns_managed::<T>() {
@@ -1583,7 +1635,31 @@ impl<T> OwnedVector<T> for ~[T] {
                 intrinsics::move_val_init(&mut(*p), t);
             }
         }
+    }
+
+    #[inline]
+    #[cfg(not(stage0))]
+    fn push(&mut self, t: T) {
+        unsafe {
+            let repr: **Vec<()> = cast::transmute(&mut *self);
+            let fill = (**repr).fill;
+            if (**repr).alloc <= fill {
+                self.reserve_additional(1);
+            }
+
+            push_fast(self, t);
+        }
 
+        // This doesn't bother to make sure we have space.
+        #[inline] // really pretty please
+        unsafe fn push_fast<T>(this: &mut ~[T], t: T) {
+            let repr: **mut Vec<u8> = cast::transmute(this);
+            let fill = (**repr).fill;
+            (**repr).fill += mem::nonzero_size_of::<T>();
+            let p = to_unsafe_ptr(&((**repr).data));
+            let p = ptr::offset(p, fill as int) as *mut T;
+            intrinsics::move_val_init(&mut(*p), t);
+        }
     }
 
     #[inline]
@@ -1746,6 +1822,7 @@ impl<T> OwnedVector<T> for ~[T] {
         }
     }
     #[inline]
+    #[cfg(stage0)]
     unsafe fn set_len(&mut self, new_len: uint) {
         if owns_managed::<T>() {
             let repr: **mut Box<Vec<()>> = cast::transmute(self);
@@ -1755,6 +1832,13 @@ impl<T> OwnedVector<T> for ~[T] {
             (**repr).fill = new_len * mem::nonzero_size_of::<T>();
         }
     }
+
+    #[inline]
+    #[cfg(not(stage0))]
+    unsafe fn set_len(&mut self, new_len: uint) {
+        let repr: **mut Vec<()> = cast::transmute(self);
+        (**repr).fill = new_len * mem::nonzero_size_of::<T>();
+    }
 }
 
 impl<T> Mutable for ~[T] {
@@ -2926,6 +3010,7 @@ impl<T> DoubleEndedIterator<T> for MoveIterator<T> {
 }
 
 #[unsafe_destructor]
+#[cfg(stage0)]
 impl<T> Drop for MoveIterator<T> {
     fn drop(&mut self) {
         // destroy the remaining elements
@@ -2940,6 +3025,18 @@ impl<T> Drop for MoveIterator<T> {
     }
 }
 
+#[unsafe_destructor]
+#[cfg(not(stage0))]
+impl<T> Drop for MoveIterator<T> {
+    fn drop(&mut self) {
+        // destroy the remaining elements
+        for _x in *self {}
+        unsafe {
+            exchange_free(self.allocation as *u8 as *c_char)
+        }
+    }
+}
+
 /// An iterator that moves out of a vector in reverse order.
 pub type MoveRevIterator<T> = Invert<MoveIterator<T>>;
 
diff --git a/src/test/debug-info/managed-pointer-within-unique-vec.rs b/src/test/debug-info/managed-pointer-within-unique-vec.rs
index 337af1ed86f..8eed28170c5 100644
--- a/src/test/debug-info/managed-pointer-within-unique-vec.rs
+++ b/src/test/debug-info/managed-pointer-within-unique-vec.rs
@@ -17,16 +17,16 @@
 // debugger:run
 // debugger:finish
 
-// debugger:print unique->val.elements[0]->val
+// debugger:print unique->elements[0]->val
 // check:$1 = 10
 
-// debugger:print unique->val.elements[1]->val
+// debugger:print unique->elements[1]->val
 // check:$2 = 11
 
-// debugger:print unique->val.elements[2]->val
+// debugger:print unique->elements[2]->val
 // check:$3 = 12
 
-// debugger:print unique->val.elements[3]->val
+// debugger:print unique->elements[3]->val
 // check:$4 = 13
 
 #[allow(unused_variable)];
diff --git a/src/test/debug-info/managed-pointer-within-unique.rs b/src/test/debug-info/managed-pointer-within-unique.rs
index db75b4bd4be..4afc8b235ed 100644
--- a/src/test/debug-info/managed-pointer-within-unique.rs
+++ b/src/test/debug-info/managed-pointer-within-unique.rs
@@ -21,28 +21,22 @@
 // debugger:print *ordinary_unique
 // check:$1 = {-1, -2}
 
-// debugger:print managed_within_unique.val->x
+// debugger:print managed_within_unique->x
 // check:$2 = -3
 
-// debugger:print managed_within_unique.val->y->val
+// debugger:print managed_within_unique->y->val
 // check:$3 = -4
 
 #[allow(unused_variable)];
 
-struct ContainsManaged
-{
-	x: int,
-	y: @int
+struct ContainsManaged {
+    x: int,
+    y: @int
 }
 
 fn main() {
+    let ordinary_unique = ~(-1, -2);
 
-	let ordinary_unique = ~(-1, -2);
-
-
-	// This is a special case: Normally values allocated in the exchange heap are not boxed, unless,
-	// however, if they contain managed pointers.
-	// This test case verifies that both cases are handled correctly.
     let managed_within_unique = ~ContainsManaged { x: -3, y: @-4 };
 
     zzz();
diff --git a/src/test/debug-info/recursive-struct.rs b/src/test/debug-info/recursive-struct.rs
index 20c8cc27f27..cf693d7e356 100644
--- a/src/test/debug-info/recursive-struct.rs
+++ b/src/test/debug-info/recursive-struct.rs
@@ -49,9 +49,9 @@
 // debugger:print stack_managed.next.val->val.value
 // check:$12 = 11
 
-// debugger:print unique_managed->val.value
+// debugger:print unique_managed->value
 // check:$13 = 12
-// debugger:print unique_managed->val.next.val->val.value
+// debugger:print unique_managed->next.val->val.value
 // check:$14 = 13
 
 // debugger:print box_managed->val.value
diff --git a/src/test/run-pass/reflect-visit-data.rs b/src/test/run-pass/reflect-visit-data.rs
index 8fc27cf8ea3..e244eace65b 100644
--- a/src/test/run-pass/reflect-visit-data.rs
+++ b/src/test/run-pass/reflect-visit-data.rs
@@ -223,13 +223,6 @@ impl<V:TyVisitor + movable_ptr> TyVisitor for ptr_visit_adaptor<V> {
         true
     }
 
-    fn visit_uniq_managed(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
-        self.align_to::<~u8>();
-        if ! self.inner().visit_uniq_managed(mtbl, inner) { return false; }
-        self.bump_past::<~u8>();
-        true
-    }
-
     fn visit_ptr(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
         self.align_to::<*u8>();
         if ! self.inner().visit_ptr(mtbl, inner) { return false; }
@@ -275,13 +268,6 @@ impl<V:TyVisitor + movable_ptr> TyVisitor for ptr_visit_adaptor<V> {
         true
     }
 
-    fn visit_evec_uniq_managed(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
-        self.align_to::<~[@u8]>();
-        if ! self.inner().visit_evec_uniq_managed(mtbl, inner) { return false; }
-        self.bump_past::<~[@u8]>();
-        true
-    }
-
     fn visit_evec_slice(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
         self.align_to::<&'static [u8]>();
         if ! self.inner().visit_evec_slice(mtbl, inner) { return false; }
@@ -549,7 +535,6 @@ impl TyVisitor for my_visitor {
 
     fn visit_box(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
     fn visit_uniq(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
-    fn visit_uniq_managed(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
     fn visit_ptr(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
     fn visit_rptr(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
 
@@ -557,7 +542,6 @@ impl TyVisitor for my_visitor {
     fn visit_unboxed_vec(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
     fn visit_evec_box(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
     fn visit_evec_uniq(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
-    fn visit_evec_uniq_managed(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
     fn visit_evec_slice(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
     fn visit_evec_fixed(&mut self, _n: uint, _sz: uint, _align: uint,
                         _mtbl: uint, _inner: *TyDesc) -> bool { true }
diff --git a/src/test/run-pass/reflect-visit-type.rs b/src/test/run-pass/reflect-visit-type.rs
index de50bb3bfed..f5871facd1d 100644
--- a/src/test/run-pass/reflect-visit-type.rs
+++ b/src/test/run-pass/reflect-visit-type.rs
@@ -70,7 +70,6 @@ impl TyVisitor for MyVisitor {
 
     fn visit_box(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
     fn visit_uniq(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
-    fn visit_uniq_managed(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
     fn visit_ptr(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
     fn visit_rptr(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
 
@@ -83,12 +82,6 @@ impl TyVisitor for MyVisitor {
         self.types.push(~"]");
         true
     }
-    fn visit_evec_uniq_managed(&mut self, _mtbl: uint, inner: *TyDesc) -> bool {
-        self.types.push(~"[");
-        unsafe { visit_tydesc(inner, &mut *self as &mut TyVisitor) };
-        self.types.push(~"]");
-        true
-    }
     fn visit_evec_slice(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { true }
     fn visit_evec_fixed(&mut self, _n: uint, _sz: uint, _align: uint,
                         _mtbl: uint, _inner: *TyDesc) -> bool { true }