rustc: update docs & propagate @[]/@str removal more.

Various functions can now be made specific to ~[], or just non-managed
vectors.

Author: huonw

doc/rust.md

@@ -3115,7 +3115,7 @@ Such a definite-sized vector type is a first-class type, since its size is known
 A vector without such a size is said to be of _indefinite_ size,
 and is therefore not a _first-class_ type.
 An indefinite-size vector can only be instantiated through a pointer type,
-such as `&[T]`, `@[T]` or `~[T]`.
+such as `&[T]` or `~[T]`.
 The kind of a vector type depends on the kind of its element type,
 as with other simple structural types.
 

src/librustc/middle/borrowck/mod.rs

@@ -194,16 +194,6 @@ pub struct BorrowStats {
 //
 // Note that there is no entry with derefs:3---the type of that expression
 // is T, which is not a box.
-//
-// Note that implicit dereferences also occur with indexing of `@[]`,
-// `@str`, etc.  The same rules apply. So, for example, given a
-// variable `x` of type `@[@[...]]`, if I have an instance of the
-// expression `x[0]` which is then auto-slice'd, there would be two
-// potential entries in the root map, both with the id of the `x[0]`
-// expression. The entry with `derefs==0` refers to the deref of `x`
-// used as part of evaluating `x[0]`. The entry with `derefs==1`
-// refers to the deref of the `x[0]` that occurs as part of the
-// auto-slice.
 #[deriving(Eq, IterBytes)]
 pub struct root_map_key {
     id: ast::NodeId,

src/librustc/middle/trans/_match.rs

@@ -1032,7 +1032,6 @@ fn match_datum(bcx: &Block,
 
 fn extract_vec_elems<'a>(
                      bcx: &'a Block<'a>,
-                     pat_span: Span,
                      pat_id: ast::NodeId,
                      elem_count: uint,
                      slice: Option<uint>,
@@ -1041,7 +1040,7 @@ fn extract_vec_elems<'a>(
                      -> ExtractedBlock<'a> {
     let _icx = push_ctxt("match::extract_vec_elems");
     let vec_datum = match_datum(bcx, val, pat_id);
-    let (bcx, base, len) = vec_datum.get_vec_base_and_len(bcx, pat_span, pat_id, 0);
+    let (base, len) = vec_datum.get_vec_base_and_len(bcx);
     let vt = tvec::vec_types(bcx, node_id_type(bcx, pat_id));
 
     let mut elems = vec::from_fn(elem_count, |i| {
@@ -1512,13 +1511,11 @@ fn compile_submatch_continue<'r,
                                 vals.slice(col + 1u, vals.len()));
     let ccx = bcx.fcx.ccx;
     let mut pat_id = 0;
-    let mut pat_span = DUMMY_SP;
     for br in m.iter() {
         // Find a real id (we're adding placeholder wildcard patterns, but
         // each column is guaranteed to have at least one real pattern)
         if pat_id == 0 {
             pat_id = br.pats[col].id;
-            pat_span = br.pats[col].span;
         }
     }
 
@@ -1767,7 +1764,7 @@ fn compile_submatch_continue<'r,
                     vec_len_ge(i) => (n + 1u, Some(i)),
                     vec_len_eq => (n, None)
                 };
-                let args = extract_vec_elems(opt_cx, pat_span, pat_id, n,
+                let args = extract_vec_elems(opt_cx, pat_id, n,
                                              slice, val, test_val);
                 size = args.vals.len();
                 unpacked = args.vals.clone();

src/librustc/middle/trans/base.rs

@@ -360,7 +360,7 @@ pub fn malloc_raw_dyn<'a>(
             None);
         rslt(r.bcx, PointerCast(r.bcx, r.val, llty_value.ptr_to()))
     } else {
-        // we treat ~fn, @fn and @[] as @ here, which isn't ideal
+        // we treat ~fn as @ here, which isn't ideal
         let langcall = match heap {
             heap_managed => {
                 require_alloc_fn(bcx, t, MallocFnLangItem)

src/librustc/middle/trans/controlflow.rs

@@ -334,7 +334,7 @@ pub fn trans_fail_expr<'a>(
                 unpack_datum!(bcx, expr::trans_to_lvalue(bcx, arg_expr, "fail"));
 
             if ty::type_is_str(arg_datum.ty) {
-                let (lldata, _) = arg_datum.get_vec_base_and_len_no_root(bcx);
+                let (lldata, _) = arg_datum.get_vec_base_and_len(bcx);
                 return trans_fail_value(bcx, sp_opt, lldata);
             } else if bcx.unreachable.get() || ty::type_is_bot(arg_datum.ty) {
                 return bcx;

src/librustc/middle/trans/datum.rs

@@ -528,49 +528,8 @@ impl Datum<Lvalue> {
         }
     }
 
-    pub fn get_vec_base_and_byte_len<'a>(
-                                     &self,
-                                     mut bcx: &'a Block<'a>,
-                                     span: Span,
-                                     expr_id: ast::NodeId,
-                                     derefs: uint)
-                                     -> (&'a Block<'a>, ValueRef, ValueRef) {
-        //! Converts a vector into the slice pair. Performs rooting
-        //! and write guards checks.
-
-        // only imp't for @[] and @str, but harmless
-        bcx = write_guard::root_and_write_guard(self, bcx, span, expr_id, derefs);
-        let (base, len) = self.get_vec_base_and_byte_len_no_root(bcx);
-        (bcx, base, len)
-    }
-
-    pub fn get_vec_base_and_byte_len_no_root(&self, bcx: &Block)
-                                             -> (ValueRef, ValueRef) {
-        //! Converts a vector into the slice pair. Des not root
-        //! nor perform write guard checks.
-
-        tvec::get_base_and_byte_len(bcx, self.val, self.ty)
-    }
-
-    pub fn get_vec_base_and_len<'a>(&self,
-                                    mut bcx: &'a Block<'a>,
-                                    span: Span,
-                                    expr_id: ast::NodeId,
-                                    derefs: uint)
-                                    -> (&'a Block<'a>, ValueRef, ValueRef) {
-        //! Converts a vector into the slice pair. Performs rooting
-        //! and write guards checks.
-
-        // only imp't for @[] and @str, but harmless
-        bcx = write_guard::root_and_write_guard(self, bcx, span, expr_id, derefs);
-        let (base, len) = self.get_vec_base_and_len_no_root(bcx);
-        (bcx, base, len)
-    }
-
-    pub fn get_vec_base_and_len_no_root<'a>(&self, bcx: &'a Block<'a>)
-                                            -> (ValueRef, ValueRef) {
-        //! Converts a vector into the slice pair. Des not root
-        //! nor perform write guard checks.
+    pub fn get_vec_base_and_len<'a>(&self, bcx: &'a Block<'a>) -> (ValueRef, ValueRef) {
+        //! Converts a vector into the slice pair.
 
         tvec::get_base_and_len(bcx, self.val, self.ty)
     }

src/librustc/middle/trans/expr.rs

@@ -202,12 +202,10 @@ fn apply_adjustments<'a>(bcx: &'a Block<'a>,
                     unpack_datum!(bcx, auto_ref(bcx, datum, expr))
                 }
                 Some(AutoBorrowVec(..)) => {
-                    unpack_datum!(bcx, auto_slice(bcx, adj.autoderefs,
-                                                  expr, datum))
+                    unpack_datum!(bcx, auto_slice(bcx, expr, datum))
                 }
                 Some(AutoBorrowVecRef(..)) => {
-                    unpack_datum!(bcx, auto_slice_and_ref(bcx, adj.autoderefs,
-                                                          expr, datum))
+                    unpack_datum!(bcx, auto_slice_and_ref(bcx, expr, datum))
                 }
                 Some(AutoBorrowFn(..)) => {
                     let adjusted_ty = ty::adjust_ty(bcx.tcx(), expr.span,
@@ -271,7 +269,6 @@ fn apply_adjustments<'a>(bcx: &'a Block<'a>,
 
     fn auto_slice<'a>(
                   bcx: &'a Block<'a>,
-                  autoderefs: uint,
                   expr: &ast::Expr,
                   datum: Datum<Expr>)
                   -> DatumBlock<'a, Expr> {
@@ -290,8 +287,7 @@ fn apply_adjustments<'a>(bcx: &'a Block<'a>,
         let datum = unpack_datum!(
             bcx, datum.to_lvalue_datum(bcx, "auto_slice", expr.id));
 
-        let (bcx, base, len) =
-            datum.get_vec_base_and_len(bcx, expr.span, expr.id, autoderefs+1);
+        let (base, len) = datum.get_vec_base_and_len(bcx);
 
         // this type may have a different region/mutability than the
         // real one, but it will have the same runtime representation
@@ -323,11 +319,10 @@ fn apply_adjustments<'a>(bcx: &'a Block<'a>,
 
     fn auto_slice_and_ref<'a>(
                           bcx: &'a Block<'a>,
-                          autoderefs: uint,
                           expr: &ast::Expr,
                           datum: Datum<Expr>)
                           -> DatumBlock<'a, Expr> {
-        let DatumBlock { bcx, datum } = auto_slice(bcx, autoderefs, expr, datum);
+        let DatumBlock { bcx, datum } = auto_slice(bcx, expr, datum);
         auto_ref(bcx, datum, expr)
     }
 
@@ -522,8 +517,7 @@ fn trans_datum_unadjusted<'a>(bcx: &'a Block<'a>,
         ast::ExprVstore(contents, ast::ExprVstoreUniq) => {
             fcx.push_ast_cleanup_scope(contents.id);
             let datum = unpack_datum!(
-                bcx, tvec::trans_uniq_or_managed_vstore(bcx, heap_exchange,
-                                                        expr, contents));
+                bcx, tvec::trans_uniq_vstore(bcx, expr, contents));
             bcx = fcx.pop_and_trans_ast_cleanup_scope(bcx, contents.id);
             DatumBlock(bcx, datum)
         }
@@ -626,8 +620,7 @@ fn trans_index<'a>(bcx: &'a Block<'a>,
     let vt = tvec::vec_types(bcx, base_datum.ty);
     base::maybe_name_value(bcx.ccx(), vt.llunit_size, "unit_sz");
 
-    let (bcx, base, len) =
-        base_datum.get_vec_base_and_len(bcx, index_expr.span, index_expr.id, 0);
+    let (base, len) = base_datum.get_vec_base_and_len(bcx);
 
     debug!("trans_index: base {}", bcx.val_to_str(base));
     debug!("trans_index: len {}", bcx.val_to_str(len));

src/librustc/middle/trans/tvec.rs

@@ -110,11 +110,10 @@ pub fn alloc_uniq_raw<'a>(
     alloc_raw(bcx, unit_ty, fill, alloc, heap_exchange)
 }
 
-pub fn alloc_vec<'a>(
+pub fn alloc_uniq_vec<'a>(
                  bcx: &'a Block<'a>,
                  unit_ty: ty::t,
-                 elts: uint,
-                 heap: heap)
+                 elts: uint)
                  -> Result<'a> {
     let _icx = push_ctxt("tvec::alloc_uniq");
     let ccx = bcx.ccx();
@@ -125,7 +124,7 @@ pub fn alloc_vec<'a>(
     let alloc = if elts < 4u { Mul(bcx, C_int(ccx, 4), unit_sz) }
                 else { fill };
     let Result {bcx: bcx, val: vptr} =
-        alloc_raw(bcx, unit_ty, fill, alloc, heap);
+        alloc_raw(bcx, unit_ty, fill, alloc, heap_exchange);
     return rslt(bcx, vptr);
 }
 
@@ -302,70 +301,62 @@ pub fn trans_lit_str<'a>(
 }
 
 
-pub fn trans_uniq_or_managed_vstore<'a>(bcx: &'a Block<'a>,
-                                        heap: heap,
-                                        vstore_expr: &ast::Expr,
-                                        content_expr: &ast::Expr)
-                                        -> DatumBlock<'a, Expr> {
+pub fn trans_uniq_vstore<'a>(bcx: &'a Block<'a>,
+                             vstore_expr: &ast::Expr,
+                             content_expr: &ast::Expr)
+                             -> DatumBlock<'a, Expr> {
     /*!
-     * @[...] or ~[...] (also @"..." or ~"...") allocate boxes in the
-     * appropriate heap and write the array elements into them.
+     * ~[...] and ~"..." allocate boxes in the exchange heap and write
+     * the array elements into them.
      */
 
-    debug!("trans_uniq_or_managed_vstore(vstore_expr={}, heap={:?})",
-           bcx.expr_to_str(vstore_expr), heap);
+    debug!("trans_uniq_vstore(vstore_expr={})", bcx.expr_to_str(vstore_expr));
     let fcx = bcx.fcx;
 
     // Handle ~"".
-    match heap {
-        heap_exchange => {
-            match content_expr.node {
-                ast::ExprLit(lit) => {
-                    match lit.node {
-                        ast::LitStr(ref s, _) => {
-                            let llptrval = C_cstr(bcx.ccx(), (*s).clone());
-                            let llptrval = PointerCast(bcx,
-                                                       llptrval,
-                                                       Type::i8p());
-                            let llsizeval = C_uint(bcx.ccx(), s.get().len());
-                            let typ = ty::mk_str(bcx.tcx(), ty::vstore_uniq);
-                            let lldestval = rvalue_scratch_datum(bcx,
-                                                                 typ,
-                                                                 "");
-                            let alloc_fn = langcall(bcx,
-                                                    Some(lit.span),
-                                                    "",
-                                                    StrDupUniqFnLangItem);
-                            let bcx = callee::trans_lang_call(
-                                bcx,
-                                alloc_fn,
-                                [ llptrval, llsizeval ],
-                                Some(expr::SaveIn(lldestval.val))).bcx;
-                            return DatumBlock(bcx, lldestval).to_expr_datumblock();
-                        }
-                        _ => {}
-                    }
+    match content_expr.node {
+        ast::ExprLit(lit) => {
+            match lit.node {
+                ast::LitStr(ref s, _) => {
+                    let llptrval = C_cstr(bcx.ccx(), (*s).clone());
+                    let llptrval = PointerCast(bcx,
+                                               llptrval,
+                                               Type::i8p());
+                    let llsizeval = C_uint(bcx.ccx(), s.get().len());
+                    let typ = ty::mk_str(bcx.tcx(), ty::vstore_uniq);
+                    let lldestval = rvalue_scratch_datum(bcx,
+                                                         typ,
+                                                         "");
+                    let alloc_fn = langcall(bcx,
+                                            Some(lit.span),
+                                            "",
+                                            StrDupUniqFnLangItem);
+                    let bcx = callee::trans_lang_call(
+                        bcx,
+                        alloc_fn,
+                        [ llptrval, llsizeval ],
+                        Some(expr::SaveIn(lldestval.val))).bcx;
+                    return DatumBlock(bcx, lldestval).to_expr_datumblock();
                 }
                 _ => {}
             }
         }
-        heap_exchange_closure => fail!("vectors use exchange_alloc"),
-        heap_managed => {}
+        _ => {}
     }
 
     let vt = vec_types_from_expr(bcx, vstore_expr);
     let count = elements_required(bcx, content_expr);
 
-    let Result {bcx, val} = alloc_vec(bcx, vt.unit_ty, count, heap);
+    let Result {bcx, val} = alloc_uniq_vec(bcx, vt.unit_ty, count);
 
     // Create a temporary scope lest execution should fail while
     // constructing the vector.
     let temp_scope = fcx.push_custom_cleanup_scope();
-    fcx.schedule_free_value(cleanup::CustomScope(temp_scope), val, heap);
+    fcx.schedule_free_value(cleanup::CustomScope(temp_scope), val, heap_exchange);
 
     let dataptr = get_dataptr(bcx, val);
 
-    debug!("alloc_vec() returned val={}, dataptr={}",
+    debug!("alloc_uniq_vec() returned val={}, dataptr={}",
            bcx.val_to_str(val), bcx.val_to_str(dataptr));
 
     let bcx = write_content(bcx, &vt, vstore_expr,

src/librustc/middle/trans/write_guard.rs

@@ -46,10 +46,10 @@ fn root<'a, K:KindOps>(datum: &Datum<K>,
                        _span: Span,
                        root_key: root_map_key,
                        root_info: RootInfo) -> &'a Block<'a> {
-    //! In some cases, borrowck will decide that an @T/@[]/@str
-    //! value must be rooted for the program to be safe.  In that
-    //! case, we will call this function, which will stash a copy
-    //! away until we exit the scope `scope_id`.
+    //! In some cases, borrowck will decide that an @T value must be
+    //! rooted for the program to be safe.  In that case, we will call
+    //! this function, which will stash a copy away until we exit the
+    //! scope `scope_id`.
 
     debug!("write_guard::root(root_key={:?}, root_info={:?}, datum={:?})",
            root_key, root_info, datum.to_str(bcx.ccx()));
@@ -62,4 +62,3 @@ fn root<'a, K:KindOps>(datum: &Datum<K>,
         cleanup::AstScope(root_info.scope), (),
         |(), bcx, llval| datum.shallow_copy_and_take(bcx, llval)).bcx
 }
-

src/librustc/middle/ty.rs

@@ -226,10 +226,10 @@ pub enum AutoRef {
     /// Convert from T to &T
     AutoPtr(Region, ast::Mutability),
 
-    /// Convert from @[]/~[]/&[] to &[] (or str)
+    /// Convert from ~[]/&[] to &[] (or str)
     AutoBorrowVec(Region, ast::Mutability),
 
-    /// Convert from @[]/~[]/&[] to &&[] (or str)
+    /// Convert from ~[]/&[] to &&[] (or str)
     AutoBorrowVecRef(Region, ast::Mutability),
 
     /// Convert from @fn()/~fn()/|| to ||

src/libsyntax/parse/parser.rs

@@ -1291,7 +1291,7 @@ impl Parser {
         }
 
         // other things are parsed as @/~ + a type.  Note that constructs like
-        // @[] and @str will be resolved during typeck to slices and so forth,
+        // ~[] and ~str will be resolved during typeck to slices and so forth,
         // rather than boxed ptrs.  But the special casing of str/vec is not
         // reflected in the AST type.
         if sigil == OwnedSigil {