auto merge of #18967 : aturon/rust/remove-runtime, r=alexcrichton

This PR completes the removal of the runtime system and green-threaded abstractions as part of implementing [RFC 230](rust-lang/rfcs#230).

Specifically:

* It removes the `Runtime` trait, welding the scheduling infrastructure directly to native threads.

* It removes `libgreen` and `libnative` entirely.

* It rewrites `sync::mutex` as a trivial layer on top of native mutexes. Eventually, the two modules will be merged.

* It hides the vast majority of `std::rt`.

This completes the basic task of removing the runtime system (I/O and scheduling) and components that depend on it. 

After this lands, a follow-up PR will pull the `rustrt` crate back into `std`, turn `std::task` into `std::thread` (with API changes to go along with it), and completely cut out the remaining startup/teardown sequence. Other changes, including new [TLS](rust-lang/rfcs#461) and synchronization are in the RFC or pre-RFC phase.

Closes #17325
Closes #18687

[breaking-change]

r? @alexcrichton

mk/crates.mk

@@ -37,7 +37,7 @@
 #
 #   DEPS_<crate>
 #	These lists are the dependencies of the <crate> that is to be built.
-#	Rust dependencies are listed bare (i.e. std, green) and native
+#	Rust dependencies are listed bare (i.e. std) and native
 #	dependencies have a "native:" prefix (i.e. native:hoedown). All deps
 #	will be built before the crate itself is built.
 #
@@ -49,7 +49,7 @@
 # automatically generated for all stage/host/target combinations.
 ################################################################################
 
-TARGET_CRATES := libc std green native flate arena term \
+TARGET_CRATES := libc std flate arena term \
                  serialize sync getopts collections test time rand \
                  log regex graphviz core rbml alloc rustrt \
                  unicode
@@ -66,8 +66,6 @@ DEPS_rustrt := alloc core libc collections native:rustrt_native
 DEPS_std := core libc rand alloc collections rustrt sync unicode \
 	native:rust_builtin native:backtrace
 DEPS_graphviz := std
-DEPS_green := std native:context_switch
-DEPS_native := std
 DEPS_syntax := std term serialize log fmt_macros arena libc
 DEPS_rustc_trans := rustc rustc_back rustc_llvm libc
 DEPS_rustc := syntax flate arena serialize getopts rbml \
@@ -95,9 +93,9 @@ DEPS_regex := std
 DEPS_regex_macros = rustc syntax std regex
 DEPS_fmt_macros = std
 
-TOOL_DEPS_compiletest := test getopts native
-TOOL_DEPS_rustdoc := rustdoc native
-TOOL_DEPS_rustc := rustc_trans native
+TOOL_DEPS_compiletest := test getopts
+TOOL_DEPS_rustdoc := rustdoc
+TOOL_DEPS_rustc := rustc_trans
 TOOL_SOURCE_compiletest := $(S)src/compiletest/compiletest.rs
 TOOL_SOURCE_rustdoc := $(S)src/driver/driver.rs
 TOOL_SOURCE_rustc := $(S)src/driver/driver.rs

src/README.md

@@ -9,8 +9,6 @@ Source layout:
 | `libcore/`          | The Rust core library                                     |
 | `libdebug/`         | Debugging utilities                                       |
 | `libstd/`           | The standard library (imported and linked by default)     |
-| `libgreen/`         | The M:N runtime library                                   |
-| `libnative/`        | The 1:1 runtime library                                   |
 | `libsyntax/`        | The Rust parser and pretty-printer                        |
 | `libtest/`          | Rust's test-runner code                                   |
 | ------------------- | --------------------------------------------------------- |

src/doc/reference.md

@@ -1059,14 +1059,14 @@ An example of what will and will not work for `use` items:
 
 ```
 # #![allow(unused_imports)]
-use foo::native::start;  // good: foo is at the root of the crate
+use foo::core::iter;  // good: foo is at the root of the crate
 use foo::baz::foobaz;    // good: foo is at the root of the crate
 
 mod foo {
-    extern crate native;
+    extern crate core;
 
-    use foo::native::start; // good: foo is at crate root
-//  use native::start;      // bad:  native is not at the crate root
+    use foo::core::iter; // good: foo is at crate root
+//  use core::iter;      // bad:  native is not at the crate root
     use self::baz::foobaz;  // good: self refers to module 'foo'
     use foo::bar::foobar;   // good: foo is at crate root
 

src/driver/driver.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![no_start]
+
 #[cfg(rustdoc)]
 extern crate "rustdoc" as this;
 

src/liballoc/lib.rs

@@ -73,7 +73,6 @@ extern crate libc;
 
 // Allow testing this library
 
-#[cfg(test)] extern crate native;
 #[cfg(test)] #[phase(plugin, link)] extern crate std;
 #[cfg(test)] #[phase(plugin, link)] extern crate log;
 

src/libcollections/lib.rs

@@ -31,7 +31,6 @@
 extern crate unicode;
 extern crate alloc;
 
-#[cfg(test)] extern crate native;
 #[cfg(test)] extern crate test;
 
 #[cfg(test)] #[phase(plugin, link)] extern crate std;

src/libcollections/slice.rs

@@ -666,6 +666,8 @@ pub mod raw {
 
 #[cfg(test)]
 mod tests {
+    extern crate rustrt;
+
     use std::cell::Cell;
     use std::default::Default;
     use std::mem;
@@ -949,9 +951,9 @@ mod tests {
     #[test]
     fn test_swap_remove_noncopyable() {
         // Tests that we don't accidentally run destructors twice.
-        let mut v = vec![rt::exclusive::Exclusive::new(()),
-                         rt::exclusive::Exclusive::new(()),
-                         rt::exclusive::Exclusive::new(())];
+        let mut v = vec![rustrt::exclusive::Exclusive::new(()),
+                         rustrt::exclusive::Exclusive::new(()),
+                         rustrt::exclusive::Exclusive::new(())];
         let mut _e = v.swap_remove(0);
         assert_eq!(v.len(), 2);
         _e = v.swap_remove(1);