---

yaml
---
r: 159226
b: refs/heads/snap-stage3
c: 4ab2235
h: refs/heads/master
v: v3

Author: aturon

[refs]

@@ -1,7 +1,7 @@
 ---
 refs/heads/master: 40fb87d40f681f5356af42175fc7b85da387f037
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
-refs/heads/snap-stage3: fcf9fb61574a415653fa0c787058972312ce1235
+refs/heads/snap-stage3: 4ab22355d4d186d5eec52be0f980034685411d04
 refs/heads/try: f58aad6dce273570fb130b4df008ef9acd5a5be2
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d

branches/snap-stage3/src/libcollections/slice.rs

@@ -89,6 +89,7 @@
 
 use self::Direction::*;
 use alloc::boxed::Box;
+use core::borrow::{BorrowFrom, BorrowFromMut};
 use core::cmp;
 use core::kinds::Sized;
 use core::mem::size_of;
@@ -647,6 +648,16 @@ impl<T> SliceAllocPrelude<T> for [T] {
     }
 }
 
+#[unstable = "trait is unstable"]
+impl<T> BorrowFrom<Vec<T>> for [T] {
+    fn borrow_from(owned: &Vec<T>) -> &[T] { owned[] }
+}
+
+#[unstable = "trait is unstable"]
+impl<T> BorrowFromMut<Vec<T>> for [T] {
+    fn borrow_from_mut(owned: &mut Vec<T>) -> &mut [T] { owned[mut] }
+}
+
 /// Unsafe operations
 pub mod raw {
     pub use core::slice::raw::{buf_as_slice, mut_buf_as_slice};

branches/snap-stage3/src/libcollections/str.rs

@@ -54,7 +54,7 @@
 pub use self::MaybeOwned::*;
 use self::RecompositionState::*;
 use self::DecompositionType::*;
-
+use core::borrow::BorrowFrom;
 use core::default::Default;
 use core::fmt;
 use core::cmp;
@@ -604,6 +604,11 @@ impl<'a> fmt::Show for MaybeOwned<'a> {
     }
 }
 
+#[unstable = "trait is unstable"]
+impl BorrowFrom<String> for str {
+    fn borrow_from(owned: &String) -> &str { owned[] }
+}
+
 /// Unsafe string operations.
 pub mod raw {
     pub use core::str::raw::{from_utf8, c_str_to_static_slice, slice_bytes};

branches/snap-stage3/src/libcore/borrow.rs

@@ -0,0 +1,126 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! A module for working with borrowed data.
+//!
+//! # The `BorrowFrom` traits
+//!
+//! In general, there may be several ways to "borrow" a piece of data.  The
+//! typical ways of borrowing a type `T` are `&T` (a shared borrow) and `&mut T`
+//! (a mutable borrow). But types like `Vec<T>` provide additional kinds of
+//! borrows: the borrowed slices `&[T]` and `&mut [T]`.
+//!
+//! When writing generic code, it is often desirable to abstract over all ways
+//! of borrowing data from a given type. That is the role of the `BorrowFrom`
+//! trait: if `T: BorrowFrom<U>`, then `&T` can be borrowed from `&U`.  A given
+//! type can be borrowed as multiple different types. In particular, `Vec<T>:
+//! BorrowFrom<Vec<T>>` and `[T]: BorrowFrom<Vec<T>>`.
+//!
+//! # The `ToOwned` trait
+//!
+//! Some types make it possible to go from borrowed to owned, usually by
+//! implementing the `Clone` trait. But `Clone` works only for going from `&T`
+//! to `T`. The `ToOwned` trait generalizes `Clone` to construct owned data
+//! from any borrow of a given type.
+//!
+//! # The `Cow` (clone-on-write) type
+//!
+//! The type `Cow` is a smart pointer providing clone-on-write functionality: it
+//! can enclose and provide immutable access to borrowed data, and clone the
+//! data lazily when mutation or ownership is required. The type is designed to
+//! work with general borrowed data via the `BorrowFrom` trait.
+//!
+//! `Cow` implements both `Deref` and `DerefMut`, which means that you can call
+//! methods directly on the data it encloses. The first time a mutable reference
+//! is required, the data will be cloned (via `to_owned`) if it is not
+//! already owned.
+
+#![unstable = "recently added as part of collections reform"]
+
+use clone::Clone;
+use kinds::Sized;
+use ops::Deref;
+
+/// A trait for borrowing data.
+pub trait BorrowFrom<Sized? Owned> for Sized? {
+    /// Immutably borrow from an owned value.
+    fn borrow_from(owned: &Owned) -> &Self;
+}
+
+/// A trait for mutably borrowing data.
+pub trait BorrowFromMut<Sized? Owned> for Sized? : BorrowFrom<Owned> {
+    /// Mutably borrow from an owned value.
+    fn borrow_from_mut(owned: &mut Owned) -> &mut Self;
+}
+
+impl<Sized? T> BorrowFrom<T> for T {
+    fn borrow_from(owned: &T) -> &T { owned }
+}
+
+impl<Sized? T> BorrowFromMut<T> for T {
+    fn borrow_from_mut(owned: &mut T) -> &mut T { owned }
+}
+
+impl BorrowFrom<&'static str> for str {
+    fn borrow_from<'a>(owned: &'a &'static str) -> &'a str { &**owned }
+}
+
+/// A generalization of Clone to borrowed data.
+pub trait ToOwned<Owned> for Sized?: BorrowFrom<Owned> {
+    /// Create owned data from borrowed data, usually by copying.
+    fn to_owned(&self) -> Owned;
+}
+
+impl<T> ToOwned<T> for T where T: Clone {
+    fn to_owned(&self) -> T { self.clone() }
+}
+
+/// A clone-on-write smart pointer.
+pub enum Cow<'a, T, B: 'a> where B: ToOwned<T> {
+    /// Borrowed data.
+    Borrowed(&'a B),
+
+    /// Owned data.
+    Owned(T)
+}
+
+impl<'a, T, B> Cow<'a, T, B> where B: ToOwned<T> {
+    /// Acquire a mutable reference to the owned form of the data.
+    ///
+    /// Copies the data if it is not already owned.
+    pub fn to_mut(&mut self) -> &mut T {
+        match *self {
+            Borrowed(borrowed) => {
+                *self = Owned(borrowed.to_owned());
+                self.to_mut()
+            }
+            Owned(ref mut owned) => owned
+        }
+    }
+
+    /// Extract the owned data.
+    ///
+    /// Copies the data if it is not already owned.
+    pub fn into_owned(self) -> T {
+        match self {
+            Borrowed(borrowed) => borrowed.to_owned(),
+            Owned(owned) => owned
+        }
+    }
+}
+
+impl<'a, T, B> Deref<B> for Cow<'a, T, B> where B: ToOwned<T>  {
+    fn deref(&self) -> &B {
+        match *self {
+            Borrowed(borrowed) => borrowed,
+            Owned(ref owned) => BorrowFrom::borrow_from(owned)
+        }
+    }
+}

branches/snap-stage3/src/libcore/lib.rs

@@ -108,6 +108,7 @@ pub mod default;
 pub mod any;
 pub mod atomic;
 pub mod bool;
+pub mod borrow;
 pub mod cell;
 pub mod char;
 pub mod panicking;

branches/snap-stage3/src/librustc/back/link.rs

@@ -728,9 +728,7 @@ fn link_staticlib(sess: &Session, obj_filename: &Path, out_filename: &Path) {
     if sess.target.target.options.morestack {
         ab.add_native_library("morestack").unwrap();
     }
-    if !sess.target.target.options.no_compiler_rt {
-        ab.add_native_library("compiler-rt").unwrap();
-    }
+    ab.add_native_library("compiler-rt").unwrap();
 
     let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
     let mut all_native_libs = vec![];

branches/snap-stage3/src/librustc/lint/builtin.rs

@@ -623,7 +623,6 @@ impl LintPass for UnusedAttributes {
             "link",
             "link_name",
             "link_section",
-            "linkage",
             "no_builtins",
             "no_mangle",
             "no_split_stack",

branches/snap-stage3/src/librustc/middle/trans/base.rs

@@ -36,7 +36,7 @@ use driver::config::{NoDebugInfo, FullDebugInfo};
 use driver::driver::{CrateAnalysis, CrateTranslation, ModuleTranslation};
 use driver::session::Session;
 use lint;
-use llvm::{BasicBlockRef, Linkage, ValueRef, Vector, get_param};
+use llvm::{BasicBlockRef, ValueRef, Vector, get_param};
 use llvm;
 use metadata::{csearch, encoder, loader};
 use middle::astencode;
@@ -2137,32 +2137,6 @@ impl<'a, 'tcx, 'v> Visitor<'v> for TransItemVisitor<'a, 'tcx> {
     }
 }
 
-pub fn llvm_linkage_by_name(name: &str) -> Option<Linkage> {
-    // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
-    // applicable to variable declarations and may not really make sense for
-    // Rust code in the first place but whitelist them anyway and trust that
-    // the user knows what s/he's doing. Who knows, unanticipated use cases
-    // may pop up in the future.
-    //
-    // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
-    // and don't have to be, LLVM treats them as no-ops.
-    match name {
-        "appending" => Some(llvm::AppendingLinkage),
-        "available_externally" => Some(llvm::AvailableExternallyLinkage),
-        "common" => Some(llvm::CommonLinkage),
-        "extern_weak" => Some(llvm::ExternalWeakLinkage),
-        "external" => Some(llvm::ExternalLinkage),
-        "internal" => Some(llvm::InternalLinkage),
-        "linkonce" => Some(llvm::LinkOnceAnyLinkage),
-        "linkonce_odr" => Some(llvm::LinkOnceODRLinkage),
-        "private" => Some(llvm::PrivateLinkage),
-        "weak" => Some(llvm::WeakAnyLinkage),
-        "weak_odr" => Some(llvm::WeakODRLinkage),
-        _ => None,
-    }
-}
-
-
 /// Enum describing the origin of an LLVM `Value`, for linkage purposes.
 pub enum ValueOrigin {
     /// The LLVM `Value` is in this context because the corresponding item was
@@ -2200,23 +2174,6 @@ pub fn update_linkage(ccx: &CrateContext,
         OriginalTranslation => {},
     }
 
-    match id {
-        Some(id) => {
-            let item = ccx.tcx().map.get(id);
-            if let ast_map::NodeItem(i) = item {
-                if let Some(name) =  attr::first_attr_value_str_by_name(i.attrs[], "linkage") {
-                    if let Some(linkage) = llvm_linkage_by_name(name.get()) {
-                        llvm::SetLinkage(llval, linkage);
-                    } else {
-                        ccx.sess().span_fatal(i.span, "invalid linkage specified");
-                    }
-                    return;
-                }
-            }
-        }
-        _ => {}
-    }
-
     match id {
         Some(id) if ccx.reachable().contains(&id) => {
             llvm::SetLinkage(llval, llvm::ExternalLinkage);

branches/snap-stage3/src/librustc/middle/trans/foreign.rs

@@ -10,10 +10,10 @@
 
 
 use back::{link};
-use llvm::{ValueRef, CallConv, get_param};
+use llvm::{ValueRef, CallConv, Linkage, get_param};
 use llvm;
 use middle::weak_lang_items;
-use middle::trans::base::{llvm_linkage_by_name, push_ctxt};
+use middle::trans::base::push_ctxt;
 use middle::trans::base;
 use middle::trans::build::*;
 use middle::trans::cabi;
@@ -101,6 +101,31 @@ pub fn llvm_calling_convention(ccx: &CrateContext,
     }
 }
 
+pub fn llvm_linkage_by_name(name: &str) -> Option<Linkage> {
+    // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
+    // applicable to variable declarations and may not really make sense for
+    // Rust code in the first place but whitelist them anyway and trust that
+    // the user knows what s/he's doing. Who knows, unanticipated use cases
+    // may pop up in the future.
+    //
+    // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
+    // and don't have to be, LLVM treats them as no-ops.
+    match name {
+        "appending" => Some(llvm::AppendingLinkage),
+        "available_externally" => Some(llvm::AvailableExternallyLinkage),
+        "common" => Some(llvm::CommonLinkage),
+        "extern_weak" => Some(llvm::ExternalWeakLinkage),
+        "external" => Some(llvm::ExternalLinkage),
+        "internal" => Some(llvm::InternalLinkage),
+        "linkonce" => Some(llvm::LinkOnceAnyLinkage),
+        "linkonce_odr" => Some(llvm::LinkOnceODRLinkage),
+        "private" => Some(llvm::PrivateLinkage),
+        "weak" => Some(llvm::WeakAnyLinkage),
+        "weak_odr" => Some(llvm::WeakODRLinkage),
+        _ => None,
+    }
+}
+
 pub fn register_static(ccx: &CrateContext,
                        foreign_item: &ast::ForeignItem) -> ValueRef {
     let ty = ty::node_id_to_type(ccx.tcx(), foreign_item.id);

branches/snap-stage3/src/libstd/lib.rs

@@ -141,6 +141,7 @@ extern crate rustrt;
 
 pub use core::any;
 pub use core::bool;
+pub use core::borrow;
 pub use core::cell;
 pub use core::clone;
 #[cfg(not(test))] pub use core::cmp;

branches/snap-stage3/src/libsyntax/feature_gate.rs

@@ -182,10 +182,6 @@ impl<'a, 'v> Visitor<'v> for Context<'a> {
                                   "`#[thread_local]` is an experimental feature, and does not \
                                   currently handle destructors. There is no corresponding \
                                   `#[task_local]` mapping to the task model");
-            } else if attr.name().equiv(&("linkage")) {
-                self.gate_feature("linkage", i.span,
-                                  "the `linkage` attribute is experimental \
-                                   and not portable across platforms")
             }
         }
         match i.node {