auto merge of #13819 : nick29581/rust/ty_str, r=pcwalton

Similar to my recent changes to ~[T]/&[T], these changes remove the vstore abstraction and represent str types as ~(str) and &(str). The Option<uint> in ty_str is the length of the string, None if the string is dynamically sized.

Author: bors

src/librustc/metadata/tydecode.rs

@@ -138,23 +138,6 @@ pub fn parse_substs_data(data: &[u8], crate_num: ast::CrateNum, pos: uint, tcx:
     parse_substs(&mut st, conv)
 }
 
-fn parse_vstore(st: &mut PState, conv: conv_did) -> ty::Vstore {
-    assert_eq!(next(st), '/');
-
-    let c = peek(st);
-    if '0' <= c && c <= '9' {
-        let n = parse_uint(st);
-        assert_eq!(next(st), '|');
-        return ty::VstoreFixed(n);
-    }
-
-    match next(st) {
-        '~' => ty::VstoreUniq,
-        '&' => ty::VstoreSlice(parse_region(st, conv)),
-        c => st.tcx.sess.bug(format!("parse_vstore(): bad input '{}'", c))
-    }
-}
-
 fn parse_size(st: &mut PState) -> Option<uint> {
     assert_eq!(next(st), '/');
 
@@ -361,8 +344,8 @@ fn parse_ty(st: &mut PState, conv: conv_did) -> ty::t {
         return ty::mk_vec(st.tcx, mt, sz);
       }
       'v' => {
-        let v = parse_vstore(st, |x,y| conv(x,y));
-        return ty::mk_str(st.tcx, v);
+        let sz = parse_size(st);
+        return ty::mk_str(st.tcx, sz);
       }
       'T' => {
         assert_eq!(next(st), '[');

src/librustc/metadata/tyencode.rs

@@ -177,21 +177,6 @@ fn enc_bound_region(w: &mut MemWriter, cx: &ctxt, br: ty::BoundRegion) {
     }
 }
 
-pub fn enc_vstore(w: &mut MemWriter, cx: &ctxt,
-                  v: ty::Vstore,
-                  enc_mut: |&mut MemWriter|) {
-    mywrite!(w, "/");
-    match v {
-        ty::VstoreFixed(u) => mywrite!(w, "{}|", u),
-        ty::VstoreUniq => mywrite!(w, "~"),
-        ty::VstoreSlice(r) => {
-            mywrite!(w, "&");
-            enc_region(w, cx, r);
-            enc_mut(w);
-        }
-    }
-}
-
 pub fn enc_trait_ref(w: &mut MemWriter, cx: &ctxt, s: &ty::TraitRef) {
     mywrite!(w, "{}|", (cx.ds)(s.def_id));
     enc_substs(w, cx, &s.substs);
@@ -275,9 +260,13 @@ fn enc_sty(w: &mut MemWriter, cx: &ctxt, st: &ty::sty) {
                 None => mywrite!(w, "|"),
             }
         }
-        ty::ty_str(v) => {
+        ty::ty_str(sz) => {
             mywrite!(w, "v");
-            enc_vstore(w, cx, v, |_| {});
+            mywrite!(w, "/");
+            match sz {
+                Some(n) => mywrite!(w, "{}|", n),
+                None => mywrite!(w, "|"),
+            }
         }
         ty::ty_closure(ref f) => {
             mywrite!(w, "f");

src/librustc/middle/check_match.rs

@@ -405,6 +405,7 @@ fn missing_ctor(cx: &MatchCheckCtxt,
       ty::ty_struct(..) => check_matrix_for_wild(cx, m),
       ty::ty_uniq(ty) | ty::ty_rptr(_, ty::mt{ty: ty, ..}) => match ty::get(ty).sty {
           ty::ty_vec(_, None) => ctor_for_slice(m),
+          ty::ty_str(None) => Some(single),
           _ => check_matrix_for_wild(cx, m),
       },
       ty::ty_enum(eid, _) => {

src/librustc/middle/effect.rs

@@ -68,6 +68,13 @@ impl<'a> EffectCheckVisitor<'a> {
         debug!("effect: checking index with base type {}",
                 ppaux::ty_to_str(self.tcx, base_type));
         match ty::get(base_type).sty {
+            ty::ty_uniq(ty) | ty::ty_rptr(_, ty::mt{ty, ..}) => match ty::get(ty).sty {
+                ty::ty_str(None) => {
+                    self.tcx.sess.span_err(e.span,
+                        "modification of string types is not allowed");
+                }
+                _ => {}
+            },
             ty::ty_str(..) => {
                 self.tcx.sess.span_err(e.span,
                     "modification of string types is not allowed");

src/librustc/middle/lint.rs

@@ -911,7 +911,7 @@ fn check_heap_type(cx: &Context, span: Span, ty: ty::t) {
                 ty::ty_box(_) => {
                     n_box += 1;
                 }
-                ty::ty_uniq(_) | ty::ty_str(ty::VstoreUniq) |
+                ty::ty_uniq(_) |
                 ty::ty_trait(~ty::TyTrait { store: ty::UniqTraitStore, .. }) |
                 ty::ty_closure(~ty::ClosureTy { store: ty::UniqTraitStore, .. }) => {
                     n_uniq += 1;

src/librustc/middle/mem_categorization.rs

@@ -174,7 +174,6 @@ pub fn opt_deref_kind(t: ty::t) -> Option<deref_kind> {
     match ty::get(t).sty {
         ty::ty_uniq(_) |
         ty::ty_trait(~ty::TyTrait { store: ty::UniqTraitStore, .. }) |
-        ty::ty_str(ty::VstoreUniq) |
         ty::ty_closure(~ty::ClosureTy {store: ty::UniqTraitStore, ..}) => {
             Some(deref_ptr(OwnedPtr))
         }
@@ -188,7 +187,6 @@ pub fn opt_deref_kind(t: ty::t) -> Option<deref_kind> {
             Some(deref_ptr(BorrowedPtr(kind, r)))
         }
 
-        ty::ty_str(ty::VstoreSlice(r)) |
         ty::ty_closure(~ty::ClosureTy {store: ty::RegionTraitStore(r, _), ..}) => {
             Some(deref_ptr(BorrowedPtr(ty::ImmBorrow, r)))
         }
@@ -207,7 +205,7 @@ pub fn opt_deref_kind(t: ty::t) -> Option<deref_kind> {
         }
 
         ty::ty_vec(_, Some(_)) |
-        ty::ty_str(ty::VstoreFixed(_)) => {
+        ty::ty_str(Some(_)) => {
             Some(deref_interior(InteriorElement(element_kind(t))))
         }
 
@@ -1306,6 +1304,7 @@ fn element_kind(t: ty::t) -> ElementKind {
         ty::ty_rptr(_, ty::mt{ty:ty, ..}) |
         ty::ty_uniq(ty) => match ty::get(ty).sty {
             ty::ty_vec(_, None) => VecElement,
+            ty::ty_str(None) => StrElement,
             _ => OtherElement
         },
         ty::ty_vec(..) => VecElement,

src/librustc/middle/trans/_match.rs

@@ -1293,40 +1293,51 @@ fn compare_values<'a>(
                   rhs: ValueRef,
                   rhs_t: ty::t)
                   -> Result<'a> {
+    fn compare_str<'a>(cx: &'a Block<'a>,
+                       lhs: ValueRef,
+                       rhs: ValueRef,
+                       rhs_t: ty::t)
+                       -> Result<'a> {
+        let did = langcall(cx, None,
+                           format!("comparison of `{}`", cx.ty_to_str(rhs_t)),
+                           StrEqFnLangItem);
+        let result = callee::trans_lang_call(cx, did, [lhs, rhs], None);
+        Result {
+            bcx: result.bcx,
+            val: bool_to_i1(result.bcx, result.val)
+        }
+    }
+
     let _icx = push_ctxt("compare_values");
     if ty::type_is_scalar(rhs_t) {
-      let rs = compare_scalar_types(cx, lhs, rhs, rhs_t, ast::BiEq);
-      return rslt(rs.bcx, rs.val);
+        let rs = compare_scalar_types(cx, lhs, rhs, rhs_t, ast::BiEq);
+        return rslt(rs.bcx, rs.val);
     }
 
     match ty::get(rhs_t).sty {
-        ty::ty_str(ty::VstoreUniq) => {
-            let scratch_lhs = alloca(cx, val_ty(lhs), "__lhs");
-            Store(cx, lhs, scratch_lhs);
-            let scratch_rhs = alloca(cx, val_ty(rhs), "__rhs");
-            Store(cx, rhs, scratch_rhs);
-            let did = langcall(cx, None,
-                               format!("comparison of `{}`", cx.ty_to_str(rhs_t)),
-                               UniqStrEqFnLangItem);
-            let result = callee::trans_lang_call(cx, did, [scratch_lhs, scratch_rhs], None);
-            Result {
-                bcx: result.bcx,
-                val: bool_to_i1(result.bcx, result.val)
-            }
-        }
-        ty::ty_str(_) => {
-            let did = langcall(cx, None,
-                               format!("comparison of `{}`", cx.ty_to_str(rhs_t)),
-                               StrEqFnLangItem);
-            let result = callee::trans_lang_call(cx, did, [lhs, rhs], None);
-            Result {
-                bcx: result.bcx,
-                val: bool_to_i1(result.bcx, result.val)
+        ty::ty_uniq(t) => match ty::get(t).sty {
+            ty::ty_str(None) => {
+                let scratch_lhs = alloca(cx, val_ty(lhs), "__lhs");
+                Store(cx, lhs, scratch_lhs);
+                let scratch_rhs = alloca(cx, val_ty(rhs), "__rhs");
+                Store(cx, rhs, scratch_rhs);
+                let did = langcall(cx, None,
+                                   format!("comparison of `{}`", cx.ty_to_str(rhs_t)),
+                                   UniqStrEqFnLangItem);
+                let result = callee::trans_lang_call(cx, did, [scratch_lhs, scratch_rhs], None);
+                Result {
+                    bcx: result.bcx,
+                    val: bool_to_i1(result.bcx, result.val)
+                }
             }
-        }
-        _ => {
-            cx.sess().bug("only scalars and strings supported in compare_values");
-        }
+            _ => cx.sess().bug("only scalars and strings supported in compare_values"),
+        },
+        ty::ty_rptr(_, mt) => match ty::get(mt.ty).sty {
+            ty::ty_str(None) => compare_str(cx, lhs, rhs, rhs_t),
+            _ => cx.sess().bug("only scalars and strings supported in compare_values"),
+        },
+        ty::ty_str(Some(_)) => compare_str(cx, lhs, rhs, rhs_t),
+        _ => cx.sess().bug("only scalars and strings supported in compare_values"),
     }
 }
 

src/librustc/middle/trans/adt.rs

@@ -270,11 +270,10 @@ impl Case {
         self.tys.iter().position(|&ty| {
             match ty::get(ty).sty {
                 ty::ty_rptr(_, mt) => match ty::get(mt.ty).sty {
-                    ty::ty_vec(_, None) => false,
+                    ty::ty_vec(_, None) | ty::ty_str(None)=> false,
                     _ => true,
                 },
                 ty::ty_uniq(..) | ty::ty_box(..) |
-                ty::ty_str(ty::VstoreUniq) |
                 ty::ty_bare_fn(..) => true,
                 // Is that everything?  Would closures or slices qualify?
                 _ => false

src/librustc/middle/trans/base.rs

@@ -188,8 +188,8 @@ fn decl_fn(llmod: ModuleRef, name: &str, cc: lib::llvm::CallConv,
         // `~` pointer return values never alias because ownership is transferred
         // FIXME #6750 ~Trait cannot be directly marked as
         // noalias because the actual object pointer is nested.
-        ty::ty_uniq(..) | // ty::ty_trait(_, _, ty::UniqTraitStore, _, _) |
-        ty::ty_str(ty::VstoreUniq) => {
+        ty::ty_uniq(..) // | ty::ty_trait(_, _, ty::UniqTraitStore, _, _)
+         => {
             unsafe {
                 llvm::LLVMAddReturnAttribute(llfn, lib::llvm::NoAliasAttribute as c_uint);
             }
@@ -261,7 +261,6 @@ pub fn decl_rust_fn(ccx: &CrateContext, has_env: bool,
             // FIXME #6750 ~Trait cannot be directly marked as
             // noalias because the actual object pointer is nested.
             ty::ty_uniq(..) | // ty::ty_trait(_, _, ty::UniqTraitStore, _, _) |
-            ty::ty_str(ty::VstoreUniq) |
             ty::ty_closure(~ty::ClosureTy {store: ty::UniqTraitStore, ..}) => {
                 unsafe {
                     llvm::LLVMAddAttribute(llarg, lib::llvm::NoAliasAttribute as c_uint);
@@ -665,7 +664,7 @@ pub fn iter_structural_ty<'r,
               }
           })
       }
-      ty::ty_str(ty::VstoreFixed(n)) => {
+      ty::ty_str(Some(n)) => {
         let unit_ty = ty::sequence_element_type(cx.tcx(), t);
         let (base, len) = tvec::get_fixed_base_and_byte_len(cx, av, unit_ty, n);
         cx = tvec::iter_vec_raw(cx, base, unit_ty, len, f);

src/librustc/middle/trans/callee.rs

@@ -659,9 +659,10 @@ pub fn trans_call_inner<'a>(
         match ty::get(ret_ty).sty {
             // `~` pointer return values never alias because ownership
             // is transferred
-            ty::ty_uniq(..) => {
-                attrs.push((0, NoAliasAttribute));
-            }
+            ty::ty_uniq(ty) => match ty::get(ty).sty {
+                ty::ty_str(None) => {}
+                _ => attrs.push((0, NoAliasAttribute)),
+            },
             _ => {}
         }