Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

26 files changed, 2870 insertions, 0 deletions

diff --git a/third_party/rust/objc/.cargo-checksum.json b/third_party/rust/objc/.cargo-checksum.json
new file mode 100644
index 0000000000..3b36dfaa71
--- /dev/null
+++ b/third_party/rust/objc/.cargo-checksum.json
@@ -0,0 +1 @@
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diff --git a/third_party/rust/objc/CHANGELOG.md b/third_party/rust/objc/CHANGELOG.md
new file mode 100644
index 0000000000..c8b1bf8944
--- /dev/null
+++ b/third_party/rust/objc/CHANGELOG.md
@@ -0,0 +1,117 @@
+## 0.2.7
+
+### Fixed
+
+* Uses of `msg_send!` will now correctly fail to compile if no return type
+  can be inferred, instead of relying on an edge case of the compiler
+  that will soon change and silently cause undefined behavior.
+
+## 0.2.6
+
+### Fixed
+
+* Suppressed a deprecation warning in `sel!`, `msg_send!`, and `class!`.
+
+## 0.2.5
+
+### Added
+
+* `autoreleasepool` returns the value returned by its body closure.
+
+## 0.2.4
+
+### Added
+
+* Added an `rc` module with reference counting utilities:
+  `StrongPtr`, `WeakPtr`, and `autoreleasepool`.
+
+* Added some reference counting ABI foreign functions to the `runtime` module.
+
+### Fixed
+
+* Messaging nil under GNUstep now correctly returns zeroed results for all
+  return types.
+
+## 0.2.3
+
+### Added
+
+* Added a `class!` macro for getting statically-known classes. The result is
+  non-optional (avoiding a need to unwrap) and cached so each usage will only
+  look up the class once.
+
+* Added caching to the `sel!` macro so that each usage will only register the
+  selector once.
+
+### Fixed
+
+* Fixed the implementation of `objc::runtime` structs so there can't be unsound
+  references to uninhabited types.
+
+## 0.2.2
+
+### Added
+
+* Implemented `Sync` and `Send` for `Sel`.
+
+## 0.2.1
+
+### Added
+
+* Added support for working with protocols with the `Protocol` struct.
+  The protocols a class conforms to can be examined with the new
+  `Class::adopted_protocols` and `Class::conforms_to` methods.
+
+* Protocols can be declared using the new `ProtocolDecl` struct.
+
+## 0.2.0
+
+### Added
+
+* Added verification for the types used when sending messages.
+  This can be enabled for all messages with the `"verify_message"` feature,
+  or you can test before sending specific messages with the
+  `Message::verify_message` method. Verification errors are reported using the
+  new `MessageError` struct.
+
+* Added support for the GNUstep runtime!
+  Operating systems besides OSX and iOS will fall back to the GNUstep runtime.
+
+* Root classes can be declared by using the `ClassDecl::root` constructor.
+
+### Changed
+
+* C types are now used from `std::os::raw` rather than `libc`. This means
+  `Encode` may not be implemented for `libc` types; switch them to the
+  `std::os::raw` equivalents instead. This avoids an issue that would arise
+  from simultaneously using different versions of the libc crate. 
+
+* Dynamic messaging was moved into the `Message` trait; instead of
+  `().send(obj, sel!(description))`, use
+  `obj.send_message(sel!(description), ())`.
+
+* Rearranged the parameters to `ClassDecl::new` for consistency; instead of
+  `ClassDecl::new(superclass, "MyObject")`, use
+  `ClassDecl::new("MyObject", superclass)`.
+
+* Overhauled the `MethodImplementation` trait. Encodings are now accessed
+  through the `MethodImplementation::Args` associated type. The `imp_for`
+  method was replaced with `imp` and no longer takes a selector or returns an
+  `UnequalArgsError`, although `ClassDecl::add_method` still validates the
+  number of arguments.
+
+* Updated the definition of `Imp` to not use the old dispatch prototypes.
+  To invoke an `Imp`, it must first be transmuted to the correct type.
+
+* Removed `objc_msgSend` functions from the `runtime` module; the availability
+  of these functions varies and they shouldn't be called without trasmuting,
+  so they are now hidden as an implementation detail of messaging.
+
+### Fixed
+
+* Corrected alignment of ivars in `ClassDecl`; declared classes may now have a
+  smaller size. 
+
+* With the `"exception"` or `"verify_message"` feature enabled, panics from
+  `msg_send!` will now be triggered from the line and file where the macro is
+  used, rather than from within the implementation of messaging.
diff --git a/third_party/rust/objc/Cargo.lock b/third_party/rust/objc/Cargo.lock
new file mode 100644
index 0000000000..122fb19384
--- /dev/null
+++ b/third_party/rust/objc/Cargo.lock
@@ -0,0 +1,41 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "gcc"
+version = "0.3.55"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "libc"
+version = "0.2.57"
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+dependencies = [
+ "libc 0.2.57 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "objc"
+version = "0.2.7"
+dependencies = [
+ "malloc_buf 0.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "objc_exception 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "objc_exception"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "gcc 0.3.55 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
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diff --git a/third_party/rust/objc/Cargo.toml b/third_party/rust/objc/Cargo.toml
new file mode 100644
index 0000000000..08272304b6
--- /dev/null
+++ b/third_party/rust/objc/Cargo.toml
@@ -0,0 +1,33 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+name = "objc"
+version = "0.2.7"
+authors = ["Steven Sheldon"]
+exclude = [".gitignore", ".travis.yml", "doc.sh", "travis_install.sh", "travis_test.sh", "tests-ios/**"]
+description = "Objective-C Runtime bindings and wrapper for Rust."
+documentation = "http://ssheldon.github.io/rust-objc/objc/"
+readme = "README.md"
+keywords = ["objective-c", "osx", "ios", "cocoa", "uikit"]
+license = "MIT"
+repository = "http://github.com/SSheldon/rust-objc"
+[dependencies.malloc_buf]
+version = "0.0"
+
+[dependencies.objc_exception]
+version = "0.1"
+optional = true
+
+[features]
+exception = ["objc_exception"]
+verify_message = []
diff --git a/third_party/rust/objc/LICENSE.txt b/third_party/rust/objc/LICENSE.txt
new file mode 100644
index 0000000000..e9ab3babc0
--- /dev/null
+++ b/third_party/rust/objc/LICENSE.txt
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) Steven Sheldon
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/third_party/rust/objc/README.md b/third_party/rust/objc/README.md
new file mode 100644
index 0000000000..55fba64840
--- /dev/null
+++ b/third_party/rust/objc/README.md
@@ -0,0 +1,99 @@
+Objective-C Runtime bindings and wrapper for Rust.
+
+* Documentation: http://ssheldon.github.io/rust-objc/objc/
+* Crate: https://crates.io/crates/objc
+
+## Messaging objects
+
+Objective-C objects can be messaged using the `msg_send!` macro:
+
+``` rust
+let cls = class!(NSObject);
+let obj: *mut Object = msg_send![cls, new];
+let hash: usize = msg_send![obj, hash];
+let is_kind: BOOL = msg_send![obj, isKindOfClass:cls];
+// Even void methods must have their return type annotated
+let _: () = msg_send![obj, release];
+```
+
+## Reference counting
+
+The utilities of the `rc` module provide ARC-like semantics for working with
+Objective-C's reference counted objects in Rust.
+A `StrongPtr` retains an object and releases the object when dropped.
+A `WeakPtr` will not retain the object, but can be upgraded to a `StrongPtr`
+and safely fails if the object has been deallocated.
+
+``` rust
+// StrongPtr will release the object when dropped
+let obj = unsafe {
+    StrongPtr::new(msg_send![class!(NSObject), new])
+};
+
+// Cloning retains the object an additional time
+let cloned = obj.clone();
+autoreleasepool(|| {
+    // Autorelease consumes the StrongPtr, but won't
+    // actually release until the end of an autoreleasepool
+    cloned.autorelease();
+});
+
+// Weak references won't retain the object
+let weak = obj.weak();
+drop(obj);
+assert!(weak.load().is_null());
+```
+
+## Declaring classes
+
+Classes can be declared using the `ClassDecl` struct. Instance variables and
+methods can then be added before the class is ultimately registered.
+
+The following example demonstrates declaring a class named `MyNumber` that has
+one ivar, a `u32` named `_number` and a `number` method that returns it:
+
+``` rust
+let superclass = class!(NSObject);
+let mut decl = ClassDecl::new("MyNumber", superclass).unwrap();
+
+// Add an instance variable
+decl.add_ivar::<u32>("_number");
+
+// Add an ObjC method for getting the number
+extern fn my_number_get(this: &Object, _cmd: Sel) -> u32 {
+    unsafe { *this.get_ivar("_number") }
+}
+unsafe {
+    decl.add_method(sel!(number),
+        my_number_get as extern fn(&Object, Sel) -> u32);
+}
+
+decl.register();
+```
+
+## Exceptions
+
+By default, if the `msg_send!` macro causes an exception to be thrown, this
+will unwind into Rust resulting in unsafe, undefined behavior.
+However, this crate has an `"exception"` feature which, when enabled, wraps
+each `msg_send!` in a `@try`/`@catch` and panics if an exception is caught,
+preventing Objective-C from unwinding into Rust.
+
+## Message type verification
+
+The Objective-C runtime includes encodings for each method that describe the
+argument and return types. This crate can take advantage of these encodings to
+verify that the types used in Rust match the types encoded for the method.
+
+To use this functionality, enable the `"verify_message"` feature.
+With this feature enabled, type checking is performed for every message send,
+which also requires that all arguments and return values for all messages
+implement `Encode`.
+
+If this requirement is burdensome or you'd rather just verify specific messages,
+you can call the `Message::verify_message` method for specific selectors.
+
+## Support for other Operating Systems
+
+The bindings can be used on Linux or *BSD utilizing the
+[GNUstep Objective-C runtime](https://www.github.com/gnustep/libobjc2).
diff --git a/third_party/rust/objc/examples/example.rs b/third_party/rust/objc/examples/example.rs
new file mode 100644
index 0000000000..5346b620fb
--- /dev/null
+++ b/third_party/rust/objc/examples/example.rs
@@ -0,0 +1,45 @@
+#[macro_use]
+extern crate objc;
+
+use objc::Encode;
+use objc::rc::StrongPtr;
+use objc::runtime::{Class, Object};
+
+fn main() {
+    // Get a class
+    let cls = class!(NSObject);
+    println!("NSObject size: {}", cls.instance_size());
+
+    // Inspect its ivars
+    println!("NSObject ivars:");
+    for ivar in cls.instance_variables().iter() {
+        println!("{}", ivar.name());
+    }
+
+    // Allocate an instance
+    let obj = unsafe {
+        let obj: *mut Object = msg_send![cls, alloc];
+        let obj: *mut Object = msg_send![obj, init];
+        StrongPtr::new(obj)
+    };
+    println!("NSObject address: {:p}", obj);
+
+    // Access an ivar of the object
+    let isa: *const Class = unsafe {
+        *(**obj).get_ivar("isa")
+    };
+    println!("NSObject isa: {:?}", isa);
+
+    // Inspect a method of the class
+    let hash_sel = sel!(hash);
+    let hash_method = cls.instance_method(hash_sel).unwrap();
+    let hash_return = hash_method.return_type();
+    println!("-[NSObject hash] return type: {:?}", hash_return);
+    assert!(hash_return == usize::encode());
+
+    // Invoke a method on the object
+    let hash: usize = unsafe {
+        msg_send![*obj, hash]
+    };
+    println!("NSObject hash: {}", hash);
+}
diff --git a/third_party/rust/objc/src/declare.rs b/third_party/rust/objc/src/declare.rs
new file mode 100644
index 0000000000..ed09015e1a
--- /dev/null
+++ b/third_party/rust/objc/src/declare.rs
@@ -0,0 +1,340 @@
+/*!
+Functionality for declaring Objective-C classes.
+
+Classes can be declared using the `ClassDecl` struct. Instance variables and
+methods can then be added before the class is ultimately registered.
+
+# Example
+
+The following example demonstrates declaring a class named `MyNumber` that has
+one ivar, a `u32` named `_number` and a `number` method that returns it:
+
+``` no_run
+# #[macro_use] extern crate objc;
+# use objc::declare::ClassDecl;
+# use objc::runtime::{Class, Object, Sel};
+# fn main() {
+let superclass = class!(NSObject);
+let mut decl = ClassDecl::new("MyNumber", superclass).unwrap();
+
+// Add an instance variable
+decl.add_ivar::<u32>("_number");
+
+// Add an ObjC method for getting the number
+extern fn my_number_get(this: &Object, _cmd: Sel) -> u32 {
+    unsafe { *this.get_ivar("_number") }
+}
+unsafe {
+    decl.add_method(sel!(number),
+        my_number_get as extern fn(&Object, Sel) -> u32);
+}
+
+decl.register();
+# }
+```
+*/
+
+use std::ffi::CString;
+use std::mem;
+use std::ptr;
+
+use runtime::{BOOL, Class, Imp, NO, Object, Protocol, Sel, self};
+use {Encode, EncodeArguments, Encoding, Message};
+
+/// Types that can be used as the implementation of an Objective-C method.
+pub trait MethodImplementation {
+    /// The callee type of the method.
+    type Callee: Message;
+    /// The return type of the method.
+    type Ret: Encode;
+    /// The argument types of the method.
+    type Args: EncodeArguments;
+
+    /// Returns self as an `Imp` of a method.
+    fn imp(self) -> Imp;
+}
+
+macro_rules! method_decl_impl {
+    (-$s:ident, $r:ident, $f:ty, $($t:ident),*) => (
+        impl<$s, $r $(, $t)*> MethodImplementation for $f
+                where $s: Message, $r: Encode $(, $t: Encode)* {
+            type Callee = $s;
+            type Ret = $r;
+            type Args = ($($t,)*);
+
+            fn imp(self) -> Imp {
+                unsafe { mem::transmute(self) }
+            }
+        }
+    );
+    ($($t:ident),*) => (
+        method_decl_impl!(-T, R, extern fn(&T, Sel $(, $t)*) -> R, $($t),*);
+        method_decl_impl!(-T, R, extern fn(&mut T, Sel $(, $t)*) -> R, $($t),*);
+    );
+}
+
+method_decl_impl!();
+method_decl_impl!(A);
+method_decl_impl!(A, B);
+method_decl_impl!(A, B, C);
+method_decl_impl!(A, B, C, D);
+method_decl_impl!(A, B, C, D, E);
+method_decl_impl!(A, B, C, D, E, F);
+method_decl_impl!(A, B, C, D, E, F, G);
+method_decl_impl!(A, B, C, D, E, F, G, H);
+method_decl_impl!(A, B, C, D, E, F, G, H, I);
+method_decl_impl!(A, B, C, D, E, F, G, H, I, J);
+method_decl_impl!(A, B, C, D, E, F, G, H, I, J, K);
+method_decl_impl!(A, B, C, D, E, F, G, H, I, J, K, L);
+
+fn count_args(sel: Sel) -> usize {
+    sel.name().chars().filter(|&c| c == ':').count()
+}
+
+fn method_type_encoding(ret: &Encoding, args: &[Encoding]) -> CString {
+    let mut types = ret.as_str().to_owned();
+    // First two arguments are always self and the selector
+    types.push_str(<*mut Object>::encode().as_str());
+    types.push_str(Sel::encode().as_str());
+    types.extend(args.iter().map(|e| e.as_str()));
+    CString::new(types).unwrap()
+}
+
+fn log2_align_of<T>() -> u8 {
+    let align = mem::align_of::<T>();
+    // Alignments are required to be powers of 2
+    debug_assert!(align.count_ones() == 1);
+    // log2 of a power of 2 is the number of trailing zeros
+    align.trailing_zeros() as u8
+}
+
+/// A type for declaring a new class and adding new methods and ivars to it
+/// before registering it.
+pub struct ClassDecl {
+    cls: *mut Class,
+}
+
+impl ClassDecl {
+    fn with_superclass(name: &str, superclass: Option<&Class>)
+            -> Option<ClassDecl> {
+        let name = CString::new(name).unwrap();
+        let super_ptr = superclass.map_or(ptr::null(), |c| c);
+        let cls = unsafe {
+            runtime::objc_allocateClassPair(super_ptr, name.as_ptr(), 0)
+        };
+        if cls.is_null() {
+            None
+        } else {
+            Some(ClassDecl { cls: cls })
+        }
+    }
+
+    /// Constructs a `ClassDecl` with the given name and superclass.
+    /// Returns `None` if the class couldn't be allocated.
+    pub fn new(name: &str, superclass: &Class) -> Option<ClassDecl> {
+        ClassDecl::with_superclass(name, Some(superclass))
+    }
+
+    /**
+    Constructs a `ClassDecl` declaring a new root class with the given name.
+    Returns `None` if the class couldn't be allocated.
+
+    An implementation for `+initialize` must also be given; the runtime calls
+    this method for all classes, so it must be defined on root classes.
+
+    Note that implementing a root class is not a simple endeavor.
+    For example, your class probably cannot be passed to Cocoa code unless
+    the entire `NSObject` protocol is implemented.
+    Functionality it expects, like implementations of `-retain` and `-release`
+    used by ARC, will not be present otherwise.
+    */
+    pub fn root(name: &str, intitialize_fn: extern fn(&Class, Sel))
+            -> Option<ClassDecl> {
+        let mut decl = ClassDecl::with_superclass(name, None);
+        if let Some(ref mut decl) = decl {
+            unsafe {
+                decl.add_class_method(sel!(initialize), intitialize_fn);
+            }
+        }
+        decl
+    }
+
+    /// Adds a method with the given name and implementation to self.
+    /// Panics if the method wasn't sucessfully added
+    /// or if the selector and function take different numbers of arguments.
+    /// Unsafe because the caller must ensure that the types match those that
+    /// are expected when the method is invoked from Objective-C.
+    pub unsafe fn add_method<F>(&mut self, sel: Sel, func: F)
+            where F: MethodImplementation<Callee=Object> {
+        let encs = F::Args::encodings();
+        let encs = encs.as_ref();
+        let sel_args = count_args(sel);
+        assert!(sel_args == encs.len(),
+            "Selector accepts {} arguments, but function accepts {}",
+            sel_args, encs.len(),
+        );
+
+        let types = method_type_encoding(&F::Ret::encode(), encs);
+        let success = runtime::class_addMethod(self.cls, sel, func.imp(),
+            types.as_ptr());
+        assert!(success != NO, "Failed to add method {:?}", sel);
+    }
+
+    /// Adds a class method with the given name and implementation to self.
+    /// Panics if the method wasn't sucessfully added
+    /// or if the selector and function take different numbers of arguments.
+    /// Unsafe because the caller must ensure that the types match those that
+    /// are expected when the method is invoked from Objective-C.
+    pub unsafe fn add_class_method<F>(&mut self, sel: Sel, func: F)
+            where F: MethodImplementation<Callee=Class> {
+        let encs = F::Args::encodings();
+        let encs = encs.as_ref();
+        let sel_args = count_args(sel);
+        assert!(sel_args == encs.len(),
+            "Selector accepts {} arguments, but function accepts {}",
+            sel_args, encs.len(),
+        );
+
+        let types = method_type_encoding(&F::Ret::encode(), encs);
+        let metaclass = (*self.cls).metaclass() as *const _ as *mut _;
+        let success = runtime::class_addMethod(metaclass, sel, func.imp(),
+            types.as_ptr());
+        assert!(success != NO, "Failed to add class method {:?}", sel);
+    }
+
+    /// Adds an ivar with type `T` and the provided name to self.
+    /// Panics if the ivar wasn't successfully added.
+    pub fn add_ivar<T>(&mut self, name: &str) where T: Encode {
+        let c_name = CString::new(name).unwrap();
+        let encoding = CString::new(T::encode().as_str()).unwrap();
+        let size = mem::size_of::<T>();
+        let align = log2_align_of::<T>();
+        let success = unsafe {
+            runtime::class_addIvar(self.cls, c_name.as_ptr(), size, align,
+                encoding.as_ptr())
+        };
+        assert!(success != NO, "Failed to add ivar {}", name);
+    }
+
+    /// Adds a protocol to self. Panics if the protocol wasn't successfully
+    /// added
+    pub fn add_protocol(&mut self, proto: &Protocol) {
+        let success = unsafe { runtime::class_addProtocol(self.cls, proto) };
+        assert!(success != NO, "Failed to add protocol {:?}", proto);
+    }
+
+    /// Registers self, consuming it and returning a reference to the
+    /// newly registered `Class`.
+    pub fn register(self) -> &'static Class {
+        unsafe {
+            let cls = self.cls;
+            runtime::objc_registerClassPair(cls);
+            // Forget self otherwise the class will be disposed in drop
+            mem::forget(self);
+            &*cls
+        }
+    }
+}
+
+impl Drop for ClassDecl {
+    fn drop(&mut self) {
+        unsafe {
+            runtime::objc_disposeClassPair(self.cls);
+        }
+    }
+}
+
+/// A type for declaring a new protocol and adding new methods to it
+/// before registering it.
+pub struct ProtocolDecl {
+    proto: *mut Protocol
+}
+
+impl ProtocolDecl {
+    /// Constructs a `ProtocolDecl` with the given name. Returns `None` if the
+    /// protocol couldn't be allocated.
+    pub fn new(name: &str) -> Option<ProtocolDecl> {
+        let c_name = CString::new(name).unwrap();
+        let proto = unsafe {
+            runtime::objc_allocateProtocol(c_name.as_ptr())
+        };
+        if proto.is_null() {
+            None
+        } else {
+            Some(ProtocolDecl { proto: proto })
+        }
+    }
+
+    fn add_method_description_common<Args, Ret>(&mut self, sel: Sel, is_required: bool,
+            is_instance_method: bool)
+            where Args: EncodeArguments,
+                  Ret: Encode {
+        let encs = Args::encodings();
+        let encs = encs.as_ref();
+        let sel_args = count_args(sel);
+        assert!(sel_args == encs.len(),
+            "Selector accepts {} arguments, but function accepts {}",
+            sel_args, encs.len(),
+        );
+        let types = method_type_encoding(&Ret::encode(), encs);
+        unsafe {
+            runtime::protocol_addMethodDescription(
+                self.proto, sel, types.as_ptr(), is_required as BOOL, is_instance_method as BOOL);
+        }
+    }
+
+    /// Adds an instance method declaration with a given description to self.
+    pub fn add_method_description<Args, Ret>(&mut self, sel: Sel, is_required: bool)
+            where Args: EncodeArguments,
+                  Ret: Encode {
+        self.add_method_description_common::<Args, Ret>(sel, is_required, true)
+    }
+
+    /// Adds a class method declaration with a given description to self.
+    pub fn add_class_method_description<Args, Ret>(&mut self, sel: Sel, is_required: bool)
+            where Args: EncodeArguments,
+                  Ret: Encode {
+        self.add_method_description_common::<Args, Ret>(sel, is_required, false)
+    }
+
+    /// Adds a requirement on another protocol.
+    pub fn add_protocol(&mut self, proto: &Protocol) {
+        unsafe {
+            runtime::protocol_addProtocol(self.proto, proto);
+        }
+    }
+
+    /// Registers self, consuming it and returning a reference to the
+    /// newly registered `Protocol`.
+    pub fn register(self) -> &'static Protocol {
+        unsafe {
+            runtime::objc_registerProtocol(self.proto);
+            &*self.proto
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils;
+
+    #[test]
+    fn test_custom_class() {
+        // Registering the custom class is in test_utils
+        let obj = test_utils::custom_object();
+        unsafe {
+            let _: () = msg_send![obj, setFoo:13u32];
+            let result: u32 = msg_send![obj, foo];
+            assert!(result == 13);
+        }
+    }
+
+    #[test]
+    fn test_class_method() {
+        let cls = test_utils::custom_class();
+        unsafe {
+            let result: u32 = msg_send![cls, classFoo];
+            assert!(result == 7);
+        }
+    }
+}
diff --git a/third_party/rust/objc/src/encode.rs b/third_party/rust/objc/src/encode.rs
new file mode 100644
index 0000000000..921479da98
--- /dev/null
+++ b/third_party/rust/objc/src/encode.rs
@@ -0,0 +1,279 @@
+use std::ffi::CStr;
+use std::fmt;
+use std::os::raw::{c_char, c_void};
+use std::str;
+use malloc_buf::MallocBuffer;
+
+use runtime::{Class, Object, Sel};
+
+const QUALIFIERS: &'static [char] = &[
+    'r', // const
+    'n', // in
+    'N', // inout
+    'o', // out
+    'O', // bycopy
+    'R', // byref
+    'V', // oneway
+];
+
+#[cfg(target_pointer_width = "64")]
+const CODE_INLINE_CAP: usize = 30;
+
+#[cfg(target_pointer_width = "32")]
+const CODE_INLINE_CAP: usize = 14;
+
+enum Code {
+    Slice(&'static str),
+    Owned(String),
+    Inline(u8, [u8; CODE_INLINE_CAP]),
+    Malloc(MallocBuffer<u8>)
+}
+
+/// An Objective-C type encoding.
+///
+/// For more information, see Apple's documentation:
+/// <https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtTypeEncodings.html>
+pub struct Encoding {
+    code: Code,
+}
+
+impl Encoding {
+    /// Constructs an `Encoding` from its string representation.
+    /// Unsafe because the caller must ensure the string is a valid encoding.
+    pub unsafe fn from_str(code: &str) -> Encoding {
+        from_str(code)
+    }
+
+    /// Returns self as a `str`.
+    pub fn as_str(&self) -> &str {
+        match self.code {
+            Code::Slice(code) => code,
+            Code::Owned(ref code) => code,
+            Code::Inline(len, ref bytes) => unsafe {
+                str::from_utf8_unchecked(&bytes[..len as usize])
+            },
+            Code::Malloc(ref buf) => unsafe {
+                str::from_utf8_unchecked(&buf[..buf.len() - 1])
+            },
+        }
+    }
+}
+
+impl Clone for Encoding {
+    fn clone(&self) -> Encoding {
+        if let Code::Slice(code) = self.code {
+            from_static_str(code)
+        } else {
+            from_str(self.as_str())
+        }
+    }
+}
+
+impl PartialEq for Encoding {
+    fn eq(&self, other: &Encoding) -> bool {
+        // strip qualifiers when comparing
+        let s = self.as_str().trim_left_matches(QUALIFIERS);
+        let o = other.as_str().trim_left_matches(QUALIFIERS);
+        s == o
+    }
+}
+
+impl fmt::Debug for Encoding {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.as_str())
+    }
+}
+
+pub fn from_static_str(code: &'static str) -> Encoding {
+    Encoding { code: Code::Slice(code) }
+}
+
+pub fn from_str(code: &str) -> Encoding {
+    if code.len() > CODE_INLINE_CAP {
+        Encoding { code: Code::Owned(code.to_owned()) }
+    } else {
+        let mut bytes = [0; CODE_INLINE_CAP];
+        for (dst, byte) in bytes.iter_mut().zip(code.bytes()) {
+            *dst = byte;
+        }
+        Encoding { code: Code::Inline(code.len() as u8, bytes) }
+    }
+}
+
+pub unsafe fn from_malloc_str(ptr: *mut c_char) -> Encoding {
+    let s = CStr::from_ptr(ptr);
+    let bytes = s.to_bytes_with_nul();
+    assert!(str::from_utf8(bytes).is_ok());
+    let buf = MallocBuffer::new(ptr as *mut u8, bytes.len()).unwrap();
+    Encoding { code: Code::Malloc(buf) }
+}
+
+/// Types that have an Objective-C type encoding.
+///
+/// Unsafe because Objective-C will make assumptions about the type (like its
+/// size and alignment) from its encoding, so the implementer must verify that
+/// the encoding is accurate.
+pub unsafe trait Encode {
+    /// Returns the Objective-C type encoding for Self.
+    fn encode() -> Encoding;
+}
+
+macro_rules! encode_impls {
+    ($($t:ty : $s:expr,)*) => ($(
+        unsafe impl Encode for $t {
+            fn encode() -> Encoding { from_static_str($s) }
+        }
+    )*);
+}
+
+encode_impls!(
+    i8: "c",
+    i16: "s",
+    i32: "i",
+    i64: "q",
+    u8: "C",
+    u16: "S",
+    u32: "I",
+    u64: "Q",
+    f32: "f",
+    f64: "d",
+    bool: "B",
+    (): "v",
+    *mut c_char: "*",
+    *const c_char: "r*",
+    *mut c_void: "^v",
+    *const c_void: "r^v",
+    Sel: ":",
+);
+
+unsafe impl Encode for isize {
+    #[cfg(target_pointer_width = "32")]
+    fn encode() -> Encoding { i32::encode() }
+
+    #[cfg(target_pointer_width = "64")]
+    fn encode() -> Encoding { i64::encode() }
+}
+
+unsafe impl Encode for usize {
+    #[cfg(target_pointer_width = "32")]
+    fn encode() -> Encoding { u32::encode() }
+
+    #[cfg(target_pointer_width = "64")]
+    fn encode() -> Encoding { u64::encode() }
+}
+
+macro_rules! encode_message_impl {
+    ($code:expr, $name:ident) => (
+        encode_message_impl!($code, $name,);
+    );
+    ($code:expr, $name:ident, $($t:ident),*) => (
+        unsafe impl<'a $(, $t)*> $crate::Encode for &'a $name<$($t),*> {
+            fn encode() -> Encoding { from_static_str($code) }
+        }
+
+        unsafe impl<'a $(, $t)*> $crate::Encode for &'a mut $name<$($t),*> {
+            fn encode() -> Encoding { from_static_str($code) }
+        }
+
+        unsafe impl<'a $(, $t)*> $crate::Encode for Option<&'a $name<$($t),*>> {
+            fn encode() -> Encoding { from_static_str($code) }
+        }
+
+        unsafe impl<'a $(, $t)*> $crate::Encode for Option<&'a mut $name<$($t),*>> {
+            fn encode() -> Encoding { from_static_str($code) }
+        }
+
+        unsafe impl<$($t),*> $crate::Encode for *const $name<$($t),*> {
+            fn encode() -> Encoding { from_static_str($code) }
+        }
+
+        unsafe impl<$($t),*> $crate::Encode for *mut $name<$($t),*> {
+            fn encode() -> Encoding { from_static_str($code) }
+        }
+    );
+}
+
+encode_message_impl!("@", Object);
+
+encode_message_impl!("#", Class);
+
+/// Types that represent a group of arguments, where each has an Objective-C
+/// type encoding.
+pub trait EncodeArguments {
+    /// The type as which the encodings for Self will be returned.
+    type Encs: AsRef<[Encoding]>;
+
+    /// Returns the Objective-C type encodings for Self.
+    fn encodings() -> Self::Encs;
+}
+
+macro_rules! count_idents {
+    () => (0);
+    ($a:ident) => (1);
+    ($a:ident, $($b:ident),+) => (1 + count_idents!($($b),*));
+}
+
+macro_rules! encode_args_impl {
+    ($($t:ident),*) => (
+        impl<$($t: Encode),*> EncodeArguments for ($($t,)*) {
+            type Encs = [Encoding; count_idents!($($t),*)];
+
+            fn encodings() -> Self::Encs {
+                [
+                    $($t::encode()),*
+                ]
+            }
+        }
+    );
+}
+
+encode_args_impl!();
+encode_args_impl!(A);
+encode_args_impl!(A, B);
+encode_args_impl!(A, B, C);
+encode_args_impl!(A, B, C, D);
+encode_args_impl!(A, B, C, D, E);
+encode_args_impl!(A, B, C, D, E, F);
+encode_args_impl!(A, B, C, D, E, F, G);
+encode_args_impl!(A, B, C, D, E, F, G, H);
+encode_args_impl!(A, B, C, D, E, F, G, H, I);
+encode_args_impl!(A, B, C, D, E, F, G, H, I, J);
+encode_args_impl!(A, B, C, D, E, F, G, H, I, J, K);
+encode_args_impl!(A, B, C, D, E, F, G, H, I, J, K, L);
+
+#[cfg(test)]
+mod tests {
+    use runtime::{Class, Object, Sel};
+    use super::{Encode, Encoding};
+
+    #[test]
+    fn test_encode() {
+        assert!(u32::encode().as_str() == "I");
+        assert!(<()>::encode().as_str() == "v");
+        assert!(<&Object>::encode().as_str() == "@");
+        assert!(<*mut Object>::encode().as_str() == "@");
+        assert!(<&Class>::encode().as_str() == "#");
+        assert!(Sel::encode().as_str() == ":");
+    }
+
+    #[test]
+    fn test_inline_encoding() {
+        let enc = unsafe { Encoding::from_str("C") };
+        assert!(enc.as_str() == "C");
+
+        let enc2 = enc.clone();
+        assert!(enc2 == enc);
+        assert!(enc2.as_str() == "C");
+    }
+
+    #[test]
+    fn test_owned_encoding() {
+        let s = "{Test=CCCCCCCCCCCCCCCCCCCCCCCCC}";
+        let enc = unsafe { Encoding::from_str(s) };
+        assert!(enc.as_str() == s);
+
+        let enc2 = enc.clone();
+        assert!(enc2 == enc);
+        assert!(enc2.as_str() == s);
+    }
+}
diff --git a/third_party/rust/objc/src/exception.rs b/third_party/rust/objc/src/exception.rs
new file mode 100644
index 0000000000..6fcfa7e87a
--- /dev/null
+++ b/third_party/rust/objc/src/exception.rs
@@ -0,0 +1,11 @@
+use objc_exception;
+
+use rc::StrongPtr;
+use runtime::Object;
+
+pub unsafe fn try<F, R>(closure: F) -> Result<R, StrongPtr>
+        where F: FnOnce() -> R {
+    objc_exception::try(closure).map_err(|exception| {
+        StrongPtr::new(exception as *mut Object)
+    })
+}
diff --git a/third_party/rust/objc/src/lib.rs b/third_party/rust/objc/src/lib.rs
new file mode 100644
index 0000000000..cdd30f5fd5
--- /dev/null
+++ b/third_party/rust/objc/src/lib.rs
@@ -0,0 +1,90 @@
+/*!
+Objective-C Runtime bindings and wrapper for Rust.
+
+# Messaging objects
+
+Objective-C objects can be messaged using the [`msg_send!`](macro.msg_send!.html) macro:
+
+``` no_run
+# #[macro_use] extern crate objc;
+# use objc::runtime::{BOOL, Class, Object};
+# fn main() {
+# unsafe {
+let cls = class!(NSObject);
+let obj: *mut Object = msg_send![cls, new];
+let hash: usize = msg_send![obj, hash];
+let is_kind: BOOL = msg_send![obj, isKindOfClass:cls];
+// Even void methods must have their return type annotated
+let _: () = msg_send![obj, release];
+# }
+# }
+```
+
+# Reference counting
+
+Utilities for reference counting Objective-C objects are provided in the
+[`rc`](rc/index.html) module.
+
+# Declaring classes
+
+Objective-C classes can even be declared from Rust using the functionality of
+the [`declare`](declare/index.html) module.
+
+# Exceptions
+
+By default, if the `msg_send!` macro causes an exception to be thrown, this
+will unwind into Rust resulting in unsafe, undefined behavior.
+However, this crate has an `"exception"` feature which, when enabled, wraps
+each `msg_send!` in a `@try`/`@catch` and panics if an exception is caught,
+preventing Objective-C from unwinding into Rust.
+
+# Message type verification
+
+The Objective-C runtime includes encodings for each method that describe the
+argument and return types. This crate can take advantage of these encodings to
+verify that the types used in Rust match the types encoded for the method.
+
+To use this functionality, enable the `"verify_message"` feature.
+With this feature enabled, type checking is performed for every message send,
+which also requires that all arguments and return values for all messages
+implement `Encode`.
+
+If this requirement is burdensome or you'd rather
+just verify specific messages, you can call the
+[`Message::verify_message`](trait.Message.html#method.verify_message) method
+for specific selectors.
+
+# Support for other Operating Systems
+
+The bindings can be used on Linux or *BSD utilizing the
+[GNUstep Objective-C runtime](https://www.github.com/gnustep/libobjc2).
+*/
+
+#![crate_name = "objc"]
+#![crate_type = "lib"]
+
+#![warn(missing_docs)]
+
+extern crate malloc_buf;
+#[cfg(feature = "exception")]
+extern crate objc_exception;
+
+pub use encode::{Encode, EncodeArguments, Encoding};
+pub use message::{Message, MessageArguments, MessageError};
+
+pub use message::send_message as __send_message;
+pub use message::send_super_message as __send_super_message;
+
+#[macro_use]
+mod macros;
+
+pub mod runtime;
+pub mod declare;
+pub mod rc;
+mod encode;
+#[cfg(feature = "exception")]
+mod exception;
+mod message;
+
+#[cfg(test)]
+mod test_utils;
diff --git a/third_party/rust/objc/src/macros.rs b/third_party/rust/objc/src/macros.rs
new file mode 100644
index 0000000000..c791f20ff9
--- /dev/null
+++ b/third_party/rust/objc/src/macros.rs
@@ -0,0 +1,148 @@
+/**
+Gets a reference to a `Class`.
+
+Panics if no class with the given name can be found.
+To check for a class that may not exist, use `Class::get`.
+
+# Example
+``` no_run
+# #[macro_use] extern crate objc;
+# fn main() {
+let cls = class!(NSObject);
+# }
+```
+*/
+#[macro_export]
+macro_rules! class {
+    ($name:ident) => ({
+        #[allow(deprecated)]
+        #[inline(always)]
+        fn get_class(name: &str) -> Option<&'static $crate::runtime::Class> {
+            unsafe {
+                #[cfg_attr(feature = "cargo-clippy", allow(replace_consts))]
+                static CLASS: ::std::sync::atomic::AtomicUsize = ::std::sync::atomic::ATOMIC_USIZE_INIT;
+                // `Relaxed` should be fine since `objc_getClass` is thread-safe.
+                let ptr = CLASS.load(::std::sync::atomic::Ordering::Relaxed) as *const $crate::runtime::Class;
+                if ptr.is_null() {
+                    let cls = $crate::runtime::objc_getClass(name.as_ptr() as *const _);
+                    CLASS.store(cls as usize, ::std::sync::atomic::Ordering::Relaxed);
+                    if cls.is_null() { None } else { Some(&*cls) }
+                } else {
+                    Some(&*ptr)
+                }
+            }
+        }
+        match get_class(concat!(stringify!($name), '\0')) {
+            Some(cls) => cls,
+            None => panic!("Class with name {} could not be found", stringify!($name)),
+        }
+    })
+}
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! sel_impl {
+    // Declare a function to hide unsafety, otherwise we can trigger the
+    // unused_unsafe lint; see rust-lang/rust#8472
+    ($name:expr) => ({
+        #[allow(deprecated)]
+        #[inline(always)]
+        fn register_sel(name: &str) -> $crate::runtime::Sel {
+            unsafe {
+                #[cfg_attr(feature = "cargo-clippy", allow(replace_consts))]
+                static SEL: ::std::sync::atomic::AtomicUsize = ::std::sync::atomic::ATOMIC_USIZE_INIT;
+                let ptr = SEL.load(::std::sync::atomic::Ordering::Relaxed) as *const ::std::os::raw::c_void;
+                // It should be fine to use `Relaxed` ordering here because `sel_registerName` is
+                // thread-safe.
+                if ptr.is_null() {
+                    let sel = $crate::runtime::sel_registerName(name.as_ptr() as *const _);
+                    SEL.store(sel.as_ptr() as usize, ::std::sync::atomic::Ordering::Relaxed);
+                    sel
+                } else {
+                    $crate::runtime::Sel::from_ptr(ptr)
+                }
+            }
+        }
+        register_sel($name)
+    })
+}
+
+/**
+Registers a selector, returning a `Sel`.
+
+# Example
+```
+# #[macro_use] extern crate objc;
+# fn main() {
+let sel = sel!(description);
+let sel = sel!(setObject:forKey:);
+# }
+```
+*/
+#[macro_export]
+macro_rules! sel {
+    ($name:ident) => ({sel_impl!(concat!(stringify!($name), '\0'))});
+    ($($name:ident :)+) => ({sel_impl!(concat!($(stringify!($name), ':'),+, '\0'))});
+}
+
+/**
+Sends a message to an object.
+
+The first argument can be any type that dereferences to a type that implements
+`Message`, like a reference, pointer, or an `Id`.
+The syntax is similar to the message syntax in Objective-C.
+Variadic arguments are not currently supported.
+
+# Example
+``` no_run
+# #[macro_use] extern crate objc;
+# use objc::runtime::Object;
+# fn main() {
+# unsafe {
+let obj: *mut Object;
+# let obj: *mut Object = 0 as *mut Object;
+let description: *const Object = msg_send![obj, description];
+let _: () = msg_send![obj, setArg1:1 arg2:2];
+# }
+# }
+```
+*/
+#[macro_export]
+macro_rules! msg_send {
+    (super($obj:expr, $superclass:expr), $name:ident) => ({
+        let sel = sel!($name);
+        let result;
+        match $crate::__send_super_message(&*$obj, $superclass, sel, ()) {
+            Err(s) => panic!("{}", s),
+            Ok(r) => result = r,
+        }
+        result
+    });
+    (super($obj:expr, $superclass:expr), $($name:ident : $arg:expr)+) => ({
+        let sel = sel!($($name:)+);
+        let result;
+        match $crate::__send_super_message(&*$obj, $superclass, sel, ($($arg,)*)) {
+            Err(s) => panic!("{}", s),
+            Ok(r) => result = r,
+        }
+        result
+    });
+    ($obj:expr, $name:ident) => ({
+        let sel = sel!($name);
+        let result;
+        match $crate::__send_message(&*$obj, sel, ()) {
+            Err(s) => panic!("{}", s),
+            Ok(r) => result = r,
+        }
+        result
+    });
+    ($obj:expr, $($name:ident : $arg:expr)+) => ({
+        let sel = sel!($($name:)+);
+        let result;
+        match $crate::__send_message(&*$obj, sel, ($($arg,)*)) {
+            Err(s) => panic!("{}", s),
+            Ok(r) => result = r,
+        }
+        result
+    });
+}
diff --git a/third_party/rust/objc/src/message/apple/arm.rs b/third_party/rust/objc/src/message/apple/arm.rs
new file mode 100644
index 0000000000..d26defc0de
--- /dev/null
+++ b/third_party/rust/objc/src/message/apple/arm.rs
@@ -0,0 +1,40 @@
+use std::any::{Any, TypeId};
+use std::mem;
+
+use runtime::Imp;
+
+extern {
+    fn objc_msgSend();
+    fn objc_msgSend_stret();
+
+    fn objc_msgSendSuper();
+    fn objc_msgSendSuper_stret();
+}
+
+pub fn msg_send_fn<R: Any>() -> Imp {
+    // Double-word sized fundamental data types don't use stret,
+    // but any composite type larger than 4 bytes does.
+    // <http://infocenter.arm.com/help/topic/com.arm.doc.ihi0042e/IHI0042E_aapcs.pdf>
+
+    let type_id = TypeId::of::<R>();
+    if mem::size_of::<R>() <= 4 ||
+            type_id == TypeId::of::<i64>() ||
+            type_id == TypeId::of::<u64>() ||
+            type_id == TypeId::of::<f64>() {
+        objc_msgSend
+    } else {
+        objc_msgSend_stret
+    }
+}
+
+pub fn msg_send_super_fn<R: Any>() -> Imp {
+    let type_id = TypeId::of::<R>();
+    if mem::size_of::<R>() <= 4 ||
+            type_id == TypeId::of::<i64>() ||
+            type_id == TypeId::of::<u64>() ||
+            type_id == TypeId::of::<f64>() {
+        objc_msgSendSuper
+    } else {
+        objc_msgSendSuper_stret
+    }
+}
diff --git a/third_party/rust/objc/src/message/apple/arm64.rs b/third_party/rust/objc/src/message/apple/arm64.rs
new file mode 100644
index 0000000000..54cfc897c5
--- /dev/null
+++ b/third_party/rust/objc/src/message/apple/arm64.rs
@@ -0,0 +1,18 @@
+use runtime::Imp;
+
+extern {
+    fn objc_msgSend();
+
+    fn objc_msgSendSuper();
+}
+
+pub fn msg_send_fn<R>() -> Imp {
+    // stret is not even available in arm64.
+    // <https://twitter.com/gparker/status/378079715824660480>
+
+    objc_msgSend
+}
+
+pub fn msg_send_super_fn<R>() -> Imp {
+    objc_msgSendSuper
+}
diff --git a/third_party/rust/objc/src/message/apple/mod.rs b/third_party/rust/objc/src/message/apple/mod.rs
new file mode 100644
index 0000000000..30f59ca870
--- /dev/null
+++ b/third_party/rust/objc/src/message/apple/mod.rs
@@ -0,0 +1,40 @@
+use std::any::Any;
+
+use runtime::{Class, Object, Sel};
+use super::{Message, MessageArguments, MessageError, Super};
+
+#[cfg(target_arch = "x86")]
+#[path = "x86.rs"]
+mod arch;
+#[cfg(target_arch = "x86_64")]
+#[path = "x86_64.rs"]
+mod arch;
+#[cfg(target_arch = "arm")]
+#[path = "arm.rs"]
+mod arch;
+#[cfg(target_arch = "aarch64")]
+#[path = "arm64.rs"]
+mod arch;
+
+use self::arch::{msg_send_fn, msg_send_super_fn};
+
+pub unsafe fn send_unverified<T, A, R>(obj: *const T, sel: Sel, args: A)
+        -> Result<R, MessageError>
+        where T: Message, A: MessageArguments, R: Any {
+    let receiver = obj as *mut T as *mut Object;
+    let msg_send_fn = msg_send_fn::<R>();
+    objc_try!({
+        A::invoke(msg_send_fn, receiver, sel, args)
+    })
+}
+
+pub unsafe fn send_super_unverified<T, A, R>(obj: *const T, superclass: &Class,
+        sel: Sel, args: A) -> Result<R, MessageError>
+        where T: Message, A: MessageArguments, R: Any {
+    let sup = Super { receiver: obj as *mut T as *mut Object, superclass: superclass };
+    let receiver = &sup as *const Super as *mut Object;
+    let msg_send_fn = msg_send_super_fn::<R>();
+    objc_try!({
+        A::invoke(msg_send_fn, receiver, sel, args)
+    })
+}
diff --git a/third_party/rust/objc/src/message/apple/x86.rs b/third_party/rust/objc/src/message/apple/x86.rs
new file mode 100644
index 0000000000..93422de24b
--- /dev/null
+++ b/third_party/rust/objc/src/message/apple/x86.rs
@@ -0,0 +1,40 @@
+use std::any::{Any, TypeId};
+use std::mem;
+
+use runtime::Imp;
+
+extern {
+    fn objc_msgSend();
+    fn objc_msgSend_fpret();
+    fn objc_msgSend_stret();
+
+    fn objc_msgSendSuper();
+    fn objc_msgSendSuper_stret();
+}
+
+pub fn msg_send_fn<R: Any>() -> Imp {
+    // Structures 1 or 2 bytes in size are placed in EAX.
+    // Structures 4 or 8 bytes in size are placed in: EAX and EDX.
+    // Structures of other sizes are placed at the address supplied by the caller.
+    // <https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/LowLevelABI/130-IA-32_Function_Calling_Conventions/IA32.html>
+
+    let type_id = TypeId::of::<R>();
+    let size = mem::size_of::<R>();
+    if type_id == TypeId::of::<f32>() ||
+            type_id == TypeId::of::<f64>() {
+        objc_msgSend_fpret
+    } else if size == 0 || size == 1 || size == 2 || size == 4 || size == 8 {
+        objc_msgSend
+    } else {
+        objc_msgSend_stret
+    }
+}
+
+pub fn msg_send_super_fn<R: Any>() -> Imp {
+    let size = mem::size_of::<R>();
+    if size == 0 || size == 1 || size == 2 || size == 4 || size == 8 {
+        objc_msgSendSuper
+    } else {
+        objc_msgSendSuper_stret
+    }
+}
diff --git a/third_party/rust/objc/src/message/apple/x86_64.rs b/third_party/rust/objc/src/message/apple/x86_64.rs
new file mode 100644
index 0000000000..49c90ce53e
--- /dev/null
+++ b/third_party/rust/objc/src/message/apple/x86_64.rs
@@ -0,0 +1,32 @@
+use std::mem;
+
+use runtime::Imp;
+
+extern {
+    fn objc_msgSend();
+    fn objc_msgSend_stret();
+
+    fn objc_msgSendSuper();
+    fn objc_msgSendSuper_stret();
+}
+
+pub fn msg_send_fn<R>() -> Imp {
+    // If the size of an object is larger than two eightbytes, it has class MEMORY.
+    // If the type has class MEMORY, then the caller provides space for the return
+    // value and passes the address of this storage.
+    // <http://people.freebsd.org/~obrien/amd64-elf-abi.pdf>
+
+    if mem::size_of::<R>() <= 16 {
+        objc_msgSend
+    } else {
+        objc_msgSend_stret
+    }
+}
+
+pub fn msg_send_super_fn<R>() -> Imp {
+    if mem::size_of::<R>() <= 16 {
+        objc_msgSendSuper
+    } else {
+        objc_msgSendSuper_stret
+    }
+}
diff --git a/third_party/rust/objc/src/message/gnustep.rs b/third_party/rust/objc/src/message/gnustep.rs
new file mode 100644
index 0000000000..2e28689cef
--- /dev/null
+++ b/third_party/rust/objc/src/message/gnustep.rs
@@ -0,0 +1,35 @@
+use std::any::Any;
+use std::mem;
+
+use runtime::{Class, Object, Imp, Sel};
+use super::{Message, MessageArguments, MessageError, Super};
+
+extern {
+    fn objc_msg_lookup(receiver: *mut Object, op: Sel) -> Imp;
+    fn objc_msg_lookup_super(sup: *const Super, sel: Sel) -> Imp;
+}
+
+pub unsafe fn send_unverified<T, A, R>(obj: *const T, sel: Sel, args: A)
+        -> Result<R, MessageError>
+        where T: Message, A: MessageArguments, R: Any {
+    if obj.is_null() {
+        return mem::zeroed();
+    }
+
+    let receiver = obj as *mut T as *mut Object;
+    let msg_send_fn = objc_msg_lookup(receiver, sel);
+    objc_try!({
+        A::invoke(msg_send_fn, receiver, sel, args)
+    })
+}
+
+pub unsafe fn send_super_unverified<T, A, R>(obj: *const T, superclass: &Class,
+        sel: Sel, args: A) -> Result<R, MessageError>
+        where T: Message, A: MessageArguments, R: Any {
+    let receiver = obj as *mut T as *mut Object;
+    let sup = Super { receiver: receiver, superclass: superclass };
+    let msg_send_fn = objc_msg_lookup_super(&sup, sel);
+    objc_try!({
+        A::invoke(msg_send_fn, receiver, sel, args)
+    })
+}
diff --git a/third_party/rust/objc/src/message/mod.rs b/third_party/rust/objc/src/message/mod.rs
new file mode 100644
index 0000000000..cb11e993a8
--- /dev/null
+++ b/third_party/rust/objc/src/message/mod.rs
@@ -0,0 +1,296 @@
+use std::any::Any;
+use std::error::Error;
+use std::fmt;
+use std::mem;
+
+use runtime::{Class, Imp, Object, Sel};
+use {Encode, EncodeArguments};
+
+#[cfg(feature = "exception")]
+macro_rules! objc_try {
+    ($b:block) => (
+        $crate::exception::try(|| $b).map_err(|exception|
+            if exception.is_null() {
+                MessageError("Uncaught exception nil".to_owned())
+            } else {
+                MessageError(format!("Uncaught exception {:?}", &**exception))
+            }
+        )
+    )
+}
+
+#[cfg(not(feature = "exception"))]
+macro_rules! objc_try {
+    ($b:block) => (Ok($b))
+}
+
+mod verify;
+
+#[cfg(any(target_os = "macos", target_os = "ios"))]
+#[path = "apple/mod.rs"]
+mod platform;
+#[cfg(not(any(target_os = "macos", target_os = "ios")))]
+#[path = "gnustep.rs"]
+mod platform;
+
+use self::platform::{send_unverified, send_super_unverified};
+use self::verify::verify_message_signature;
+
+/// Specifies the superclass of an instance.
+#[repr(C)]
+pub struct Super {
+    /// Specifies an instance of a class.
+    pub receiver: *mut Object,
+    /// Specifies the particular superclass of the instance to message.
+    pub superclass: *const Class,
+}
+
+/// Types that may be sent Objective-C messages.
+/// For example: objects, classes, and blocks.
+pub unsafe trait Message {
+    /**
+    Sends a message to self with the given selector and arguments.
+
+    The correct version of `objc_msgSend` will be chosen based on the
+    return type. For more information, see Apple's documentation:
+    <https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ObjCRuntimeRef/index.html#//apple_ref/doc/uid/TP40001418-CH1g-88778>
+
+    If the selector is known at compile-time, it is recommended to use the
+    `msg_send!` macro rather than this method.
+    */
+    #[cfg(not(feature = "verify_message"))]
+    unsafe fn send_message<A, R>(&self, sel: Sel, args: A)
+            -> Result<R, MessageError>
+            where Self: Sized, A: MessageArguments, R: Any {
+        send_message(self, sel, args)
+    }
+
+    #[cfg(feature = "verify_message")]
+    unsafe fn send_message<A, R>(&self, sel: Sel, args: A)
+            -> Result<R, MessageError>
+            where Self: Sized, A: MessageArguments + EncodeArguments,
+            R: Any + Encode {
+        send_message(self, sel, args)
+    }
+
+    /**
+    Verifies that the argument and return types match the encoding of the
+    method for the given selector.
+
+    This will look up the encoding of the method for the given selector, `sel`,
+    and return a `MessageError` if any encodings differ for the arguments `A`
+    and return type `R`.
+
+    # Example
+    ``` no_run
+    # #[macro_use] extern crate objc;
+    # use objc::runtime::{BOOL, Class, Object};
+    # use objc::Message;
+    # fn main() {
+    let obj: &Object;
+    # obj = unsafe { msg_send![class!(NSObject), new] };
+    let sel = sel!(isKindOfClass:);
+    // Verify isKindOfClass: takes one Class and returns a BOOL
+    let result = obj.verify_message::<(&Class,), BOOL>(sel);
+    assert!(result.is_ok());
+    # }
+    ```
+    */
+    fn verify_message<A, R>(&self, sel: Sel) -> Result<(), MessageError>
+            where Self: Sized, A: EncodeArguments, R: Encode {
+        let obj = unsafe { &*(self as *const _ as *const Object) };
+        verify_message_signature::<A, R>(obj.class(), sel)
+    }
+}
+
+unsafe impl Message for Object { }
+
+unsafe impl Message for Class { }
+
+/// Types that may be used as the arguments of an Objective-C message.
+pub trait MessageArguments: Sized {
+    /// Invoke an `Imp` with the given object, selector, and arguments.
+    ///
+    /// This method is the primitive used when sending messages and should not
+    /// be called directly; instead, use the `msg_send!` macro or, in cases
+    /// with a dynamic selector, the `Message::send_message` method.
+    unsafe fn invoke<R>(imp: Imp, obj: *mut Object, sel: Sel, args: Self) -> R
+            where R: Any;
+}
+
+macro_rules! message_args_impl {
+    ($($a:ident : $t:ident),*) => (
+        impl<$($t),*> MessageArguments for ($($t,)*) {
+            unsafe fn invoke<R>(imp: Imp, obj: *mut Object, sel: Sel, ($($a,)*): Self) -> R
+                    where R: Any {
+                let imp: unsafe extern fn(*mut Object, Sel $(, $t)*) -> R =
+                    mem::transmute(imp);
+                imp(obj, sel $(, $a)*)
+            }
+        }
+    );
+}
+
+message_args_impl!();
+message_args_impl!(a: A);
+message_args_impl!(a: A, b: B);
+message_args_impl!(a: A, b: B, c: C);
+message_args_impl!(a: A, b: B, c: C, d: D);
+message_args_impl!(a: A, b: B, c: C, d: D, e: E);
+message_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F);
+message_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G);
+message_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H);
+message_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I);
+message_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J);
+message_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K);
+message_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K, l: L);
+
+/**
+An error encountered while attempting to send a message.
+
+Currently, an error may be returned in two cases:
+
+* an Objective-C exception is thrown and the `exception` feature is enabled
+* the encodings of the arguments do not match the encoding of the method
+  and the `verify_message` feature is enabled
+*/
+#[derive(Debug)]
+pub struct MessageError(String);
+
+impl fmt::Display for MessageError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(&self.0, f)
+    }
+}
+
+impl Error for MessageError {
+    fn description(&self) -> &str {
+        &self.0
+    }
+}
+
+#[doc(hidden)]
+#[inline(always)]
+#[cfg(not(feature = "verify_message"))]
+pub unsafe fn send_message<T, A, R>(obj: *const T, sel: Sel, args: A)
+        -> Result<R, MessageError>
+        where T: Message, A: MessageArguments, R: Any {
+    send_unverified(obj, sel, args)
+}
+
+#[doc(hidden)]
+#[inline(always)]
+#[cfg(feature = "verify_message")]
+pub unsafe fn send_message<T, A, R>(obj: *const T, sel: Sel, args: A)
+        -> Result<R, MessageError>
+        where T: Message, A: MessageArguments + EncodeArguments,
+        R: Any + Encode {
+    let cls = if obj.is_null() {
+        return Err(MessageError(format!("Messaging {:?} to nil", sel)));
+    } else {
+        (*(obj as *const Object)).class()
+    };
+
+    verify_message_signature::<A, R>(cls, sel).and_then(|_| {
+        send_unverified(obj, sel, args)
+    })
+}
+
+#[doc(hidden)]
+#[inline(always)]
+#[cfg(not(feature = "verify_message"))]
+pub unsafe fn send_super_message<T, A, R>(obj: *const T, superclass: &Class,
+        sel: Sel, args: A) -> Result<R, MessageError>
+        where T: Message, A: MessageArguments, R: Any {
+    send_super_unverified(obj, superclass, sel, args)
+}
+
+#[doc(hidden)]
+#[inline(always)]
+#[cfg(feature = "verify_message")]
+pub unsafe fn send_super_message<T, A, R>(obj: *const T, superclass: &Class,
+        sel: Sel, args: A) -> Result<R, MessageError>
+        where T: Message, A: MessageArguments + EncodeArguments,
+        R: Any + Encode {
+    if obj.is_null() {
+        return Err(MessageError(format!("Messaging {:?} to nil", sel)));
+    }
+
+    verify_message_signature::<A, R>(superclass, sel).and_then(|_| {
+        send_super_unverified(obj, superclass, sel, args)
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils;
+    use runtime::Object;
+    use super::Message;
+
+    #[test]
+    fn test_send_message() {
+        let obj = test_utils::custom_object();
+        let result: u32 = unsafe {
+            let _: () = msg_send![obj, setFoo:4u32];
+            msg_send![obj, foo]
+        };
+        assert!(result == 4);
+    }
+
+    #[test]
+    fn test_send_message_stret() {
+        let obj = test_utils::custom_object();
+        let result: test_utils::CustomStruct = unsafe {
+            msg_send![obj, customStruct]
+        };
+        let expected = test_utils::CustomStruct { a: 1, b:2, c: 3, d: 4 };
+        assert!(result == expected);
+    }
+
+    #[cfg(not(feature = "verify_message"))]
+    #[test]
+    fn test_send_message_nil() {
+        let nil: *mut Object = ::std::ptr::null_mut();
+        let result: usize = unsafe {
+            msg_send![nil, hash]
+        };
+        assert!(result == 0);
+
+        let result: *mut Object = unsafe {
+            msg_send![nil, description]
+        };
+        assert!(result.is_null());
+
+        let result: f64 = unsafe {
+            msg_send![nil, doubleValue]
+        };
+        assert!(result == 0.0);
+    }
+
+    #[test]
+    fn test_send_message_super() {
+        let obj = test_utils::custom_subclass_object();
+        let superclass = test_utils::custom_class();
+        unsafe {
+            let _: () = msg_send![obj, setFoo:4u32];
+            let foo: u32 = msg_send![super(obj, superclass), foo];
+            assert!(foo == 4);
+
+            // The subclass is overriden to return foo + 2
+            let foo: u32 = msg_send![obj, foo];
+            assert!(foo == 6);
+        }
+    }
+
+    #[test]
+    fn test_verify_message() {
+        let obj = test_utils::custom_object();
+        assert!(obj.verify_message::<(), u32>(sel!(foo)).is_ok());
+        assert!(obj.verify_message::<(u32,), ()>(sel!(setFoo:)).is_ok());
+
+        // Incorrect types
+        assert!(obj.verify_message::<(), u64>(sel!(setFoo:)).is_err());
+        // Unimplemented selector
+        assert!(obj.verify_message::<(u32,), ()>(sel!(setFoo)).is_err());
+    }
+}
diff --git a/third_party/rust/objc/src/message/verify.rs b/third_party/rust/objc/src/message/verify.rs
new file mode 100644
index 0000000000..61bd4ebb39
--- /dev/null
+++ b/third_party/rust/objc/src/message/verify.rs
@@ -0,0 +1,49 @@
+use runtime::{Class, Object, Sel};
+use {Encode, EncodeArguments};
+use super::MessageError;
+
+pub fn verify_message_signature<A, R>(cls: &Class, sel: Sel)
+        -> Result<(), MessageError>
+        where A: EncodeArguments, R: Encode {
+    let method = match cls.instance_method(sel) {
+        Some(method) => method,
+        None => return Err(MessageError(
+            format!("Method {:?} not found on class {:?}",
+                sel, cls)
+        )),
+    };
+
+    let ret = R::encode();
+    let expected_ret = method.return_type();
+    if ret != expected_ret {
+        return Err(MessageError(
+            format!("Return type code {:?} does not match expected {:?} for method {:?}",
+                ret, expected_ret, method.name())
+        ));
+    }
+
+    let self_and_cmd = [<*mut Object>::encode(), Sel::encode()];
+    let args = A::encodings();
+    let args = args.as_ref();
+
+    let count = self_and_cmd.len() + args.len();
+    let expected_count = method.arguments_count();
+    if count != expected_count {
+        return Err(MessageError(
+            format!("Method {:?} accepts {} arguments, but {} were given",
+                method.name(), expected_count, count)
+        ));
+    }
+
+    for (i, arg) in self_and_cmd.iter().chain(args).enumerate() {
+        let expected = method.argument_type(i).unwrap();
+        if *arg != expected {
+            return Err(MessageError(
+                format!("Method {:?} expected argument at index {} with type code {:?} but was given {:?}",
+                    method.name(), i, expected, arg)
+            ));
+        }
+    }
+
+    Ok(())
+}
diff --git a/third_party/rust/objc/src/rc/autorelease.rs b/third_party/rust/objc/src/rc/autorelease.rs
new file mode 100644
index 0000000000..ad7a5e2847
--- /dev/null
+++ b/third_party/rust/objc/src/rc/autorelease.rs
@@ -0,0 +1,30 @@
+use std::os::raw::c_void;
+use runtime::{objc_autoreleasePoolPush, objc_autoreleasePoolPop};
+
+// we use a struct to ensure that objc_autoreleasePoolPop during unwinding.
+struct AutoReleaseHelper {
+    context: *mut c_void,
+}
+
+impl AutoReleaseHelper {
+    unsafe fn new() -> Self {
+        AutoReleaseHelper { context: objc_autoreleasePoolPush() }
+    }
+}
+
+impl Drop for AutoReleaseHelper {
+    fn drop(&mut self) {
+        unsafe { objc_autoreleasePoolPop(self.context) }
+    }
+}
+
+/**
+Execute `f` in the context of a new autorelease pool. The pool is drained
+after the execution of `f` completes.
+
+This corresponds to `@autoreleasepool` blocks in Objective-C and Swift.
+*/
+pub fn autoreleasepool<T, F: FnOnce() -> T>(f: F) -> T {
+    let _context = unsafe { AutoReleaseHelper::new() };
+    f()
+}
diff --git a/third_party/rust/objc/src/rc/mod.rs b/third_party/rust/objc/src/rc/mod.rs
new file mode 100644
index 0000000000..f6d26f7a1b
--- /dev/null
+++ b/third_party/rust/objc/src/rc/mod.rs
@@ -0,0 +1,123 @@
+/*!
+Utilities for reference counting Objective-C objects.
+
+The utilities of the `rc` module provide ARC-like semantics for working with
+Objective-C's reference counted objects in Rust.
+A `StrongPtr` retains an object and releases the object when dropped.
+A `WeakPtr` will not retain the object, but can be upgraded to a `StrongPtr`
+and safely fails if the object has been deallocated.
+
+These utilities are not intended to provide a fully safe interface, but can be
+useful when writing higher-level Rust wrappers for Objective-C code.
+
+For more information on Objective-C's reference counting, see Apple's documentation:
+<https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/MemoryMgmt/Articles/MemoryMgmt.html>
+
+# Example
+
+``` no_run
+# #[macro_use] extern crate objc;
+# use objc::rc::{autoreleasepool, StrongPtr};
+# fn main() {
+// StrongPtr will release the object when dropped
+let obj = unsafe {
+    StrongPtr::new(msg_send![class!(NSObject), new])
+};
+
+// Cloning retains the object an additional time
+let cloned = obj.clone();
+autoreleasepool(|| {
+    // Autorelease consumes the StrongPtr, but won't
+    // actually release until the end of an autoreleasepool
+    cloned.autorelease();
+});
+
+// Weak references won't retain the object
+let weak = obj.weak();
+drop(obj);
+assert!(weak.load().is_null());
+# }
+```
+*/
+
+mod strong;
+mod weak;
+mod autorelease;
+
+pub use self::strong::StrongPtr;
+pub use self::weak::WeakPtr;
+pub use self::autorelease::autoreleasepool;
+
+// These tests use NSObject, which isn't present for GNUstep
+#[cfg(all(test, any(target_os = "macos", target_os = "ios")))]
+mod tests {
+    use runtime::Object;
+    use super::StrongPtr;
+    use super::autoreleasepool;
+
+    #[test]
+    fn test_strong_clone() {
+        fn retain_count(obj: *mut Object) -> usize {
+            unsafe { msg_send![obj, retainCount] }
+        }
+
+        let obj = unsafe {
+            StrongPtr::new(msg_send![class!(NSObject), new])
+        };
+        assert!(retain_count(*obj) == 1);
+
+        let cloned = obj.clone();
+        assert!(retain_count(*cloned) == 2);
+        assert!(retain_count(*obj) == 2);
+
+        drop(obj);
+        assert!(retain_count(*cloned) == 1);
+    }
+
+    #[test]
+    fn test_weak() {
+        let obj = unsafe {
+            StrongPtr::new(msg_send![class!(NSObject), new])
+        };
+        let weak = obj.weak();
+
+        let strong = weak.load();
+        assert!(*strong == *obj);
+        drop(strong);
+
+        drop(obj);
+        assert!(weak.load().is_null());
+    }
+
+    #[test]
+    fn test_weak_copy() {
+        let obj = unsafe {
+            StrongPtr::new(msg_send![class!(NSObject), new])
+        };
+        let weak = obj.weak();
+
+        let weak2 = weak.clone();
+        let strong = weak2.load();
+        assert!(*strong == *obj);
+    }
+
+    #[test]
+    fn test_autorelease() {
+        let obj = unsafe {
+            StrongPtr::new(msg_send![class!(NSObject), new])
+        };
+
+        fn retain_count(obj: *mut Object) -> usize {
+            unsafe { msg_send![obj, retainCount] }
+        }
+        let cloned = obj.clone();
+
+        autoreleasepool(|| {
+                        obj.autorelease();
+                        assert!(retain_count(*cloned) == 2);
+        });
+
+        // make sure that the autoreleased value has been released
+        assert!(retain_count(*cloned) == 1);
+    }
+}
diff --git a/third_party/rust/objc/src/rc/strong.rs b/third_party/rust/objc/src/rc/strong.rs
new file mode 100644
index 0000000000..a61881b6ff
--- /dev/null
+++ b/third_party/rust/objc/src/rc/strong.rs
@@ -0,0 +1,73 @@
+use std::fmt;
+use std::mem;
+use std::ops::Deref;
+
+use runtime::{Object, self};
+use super::WeakPtr;
+
+/// A pointer that strongly references an object, ensuring it won't be deallocated.
+pub struct StrongPtr(*mut Object);
+
+impl StrongPtr {
+    /// Constructs a `StrongPtr` to a newly created object that already has a
+    /// +1 retain count. This will not retain the object.
+    /// When dropped, the object will be released.
+    /// Unsafe because the caller must ensure the given object pointer is valid.
+    pub unsafe fn new(ptr: *mut Object) -> Self {
+        StrongPtr(ptr)
+    }
+
+    /// Retains the given object and constructs a `StrongPtr` to it.
+    /// When dropped, the object will be released.
+    /// Unsafe because the caller must ensure the given object pointer is valid.
+    pub unsafe fn retain(ptr: *mut Object) -> Self {
+        StrongPtr(runtime::objc_retain(ptr))
+    }
+
+    /// Autoreleases self, meaning that the object is not immediately released,
+    /// but will be when the autorelease pool is drained. A pointer to the
+    /// object is returned, but its validity is no longer ensured.
+    pub fn autorelease(self) -> *mut Object {
+        let ptr = self.0;
+        mem::forget(self);
+        unsafe {
+            runtime::objc_autorelease(ptr);
+        }
+        ptr
+    }
+
+    /// Returns a `WeakPtr` to self.
+    pub fn weak(&self) -> WeakPtr {
+        unsafe { WeakPtr::new(self.0) }
+    }
+}
+
+impl Drop for StrongPtr {
+    fn drop(&mut self) {
+        unsafe {
+            runtime::objc_release(self.0);
+        }
+    }
+}
+
+impl Clone for StrongPtr {
+    fn clone(&self) -> StrongPtr {
+        unsafe {
+            StrongPtr::retain(self.0)
+        }
+    }
+}
+
+impl Deref for StrongPtr {
+    type Target = *mut Object;
+
+    fn deref(&self) -> &*mut Object {
+        &self.0
+    }
+}
+
+impl fmt::Pointer for StrongPtr {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Pointer::fmt(&self.0, f)
+    }
+}
diff --git a/third_party/rust/objc/src/rc/weak.rs b/third_party/rust/objc/src/rc/weak.rs
new file mode 100644
index 0000000000..289bd8dedb
--- /dev/null
+++ b/third_party/rust/objc/src/rc/weak.rs
@@ -0,0 +1,50 @@
+use std::cell::UnsafeCell;
+use std::ptr;
+
+use runtime::{Object, self};
+use super::StrongPtr;
+
+// Our pointer must have the same address even if we are moved, so Box it.
+// Although loading the WeakPtr may modify the pointer, it is thread safe,
+// so we must use an UnsafeCell to get a *mut without self being mutable.
+
+/// A pointer that weakly references an object, allowing to safely check
+/// whether it has been deallocated.
+pub struct WeakPtr(Box<UnsafeCell<*mut Object>>);
+
+impl WeakPtr {
+    /// Constructs a `WeakPtr` to the given object.
+    /// Unsafe because the caller must ensure the given object pointer is valid.
+    pub unsafe fn new(obj: *mut Object) -> Self {
+        let ptr = Box::new(UnsafeCell::new(ptr::null_mut()));
+        runtime::objc_initWeak(ptr.get(), obj);
+        WeakPtr(ptr)
+    }
+
+    /// Loads the object self points to, returning a `StrongPtr`.
+    /// If the object has been deallocated, the returned pointer will be null.
+    pub fn load(&self) -> StrongPtr {
+        unsafe {
+            let ptr = runtime::objc_loadWeakRetained(self.0.get());
+            StrongPtr::new(ptr)
+        }
+    }
+}
+
+impl Drop for WeakPtr {
+    fn drop(&mut self) {
+        unsafe {
+            runtime::objc_destroyWeak(self.0.get());
+        }
+    }
+}
+
+impl Clone for WeakPtr {
+    fn clone(&self) -> Self {
+        let ptr = Box::new(UnsafeCell::new(ptr::null_mut()));
+        unsafe {
+            runtime::objc_copyWeak(ptr.get(), self.0.get());
+        }
+        WeakPtr(ptr)
+    }
+}
diff --git a/third_party/rust/objc/src/runtime.rs b/third_party/rust/objc/src/runtime.rs
new file mode 100644
index 0000000000..3b533efe6f
--- /dev/null
+++ b/third_party/rust/objc/src/runtime.rs
@@ -0,0 +1,632 @@
+//! A Rust interface for the functionality of the Objective-C runtime.
+//!
+//! For more information on foreign functions, see Apple's documentation:
+//! <https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ObjCRuntimeRef/index.html>
+
+use std::ffi::{CStr, CString};
+use std::fmt;
+use std::os::raw::{c_char, c_int, c_uint, c_void};
+use std::ptr;
+use std::str;
+use malloc_buf::MallocBuffer;
+
+use encode;
+use {Encode, Encoding};
+
+/// The Objective-C `BOOL` type.
+///
+/// To convert an Objective-C `BOOL` into a Rust `bool`, compare it with `NO`.
+#[cfg(not(target_arch = "aarch64"))]
+pub type BOOL = ::std::os::raw::c_schar;
+/// The equivalent of true for Objective-C's `BOOL` type.
+#[cfg(not(target_arch = "aarch64"))]
+pub const YES: BOOL = 1;
+/// The equivalent of false for Objective-C's `BOOL` type.
+#[cfg(not(target_arch = "aarch64"))]
+pub const NO: BOOL = 0;
+
+#[cfg(target_arch = "aarch64")]
+pub type BOOL = bool;
+#[cfg(target_arch = "aarch64")]
+pub const YES: BOOL = true;
+#[cfg(target_arch = "aarch64")]
+pub const NO: BOOL = false;
+
+/// A type that represents a method selector.
+#[repr(C)]
+pub struct Sel {
+    ptr: *const c_void,
+}
+
+/// A marker type to be embedded into other types just so that they cannot be
+/// constructed externally.
+type PrivateMarker = [u8; 0];
+
+/// A type that represents an instance variable.
+#[repr(C)]
+pub struct Ivar {
+    _priv: PrivateMarker,
+}
+
+/// A type that represents a method in a class definition.
+#[repr(C)]
+pub struct Method {
+    _priv: PrivateMarker,
+}
+
+/// A type that represents an Objective-C class.
+#[repr(C)]
+pub struct Class {
+    _priv: PrivateMarker,
+}
+
+/// A type that represents an Objective-C protocol.
+#[repr(C)]
+pub struct Protocol {
+    _priv: PrivateMarker
+}
+
+/// A type that represents an instance of a class.
+#[repr(C)]
+pub struct Object {
+    _priv: PrivateMarker,
+}
+
+/// A pointer to the start of a method implementation.
+pub type Imp = unsafe extern fn();
+
+#[link(name = "objc", kind = "dylib")]
+extern {
+    pub fn sel_registerName(name: *const c_char) -> Sel;
+    pub fn sel_getName(sel: Sel) -> *const c_char;
+
+    pub fn class_getName(cls: *const Class) -> *const c_char;
+    pub fn class_getSuperclass(cls: *const Class) -> *const Class;
+    pub fn class_getInstanceSize(cls: *const Class) -> usize;
+    pub fn class_getInstanceMethod(cls: *const Class, sel: Sel) -> *const Method;
+    pub fn class_getInstanceVariable(cls: *const Class, name: *const c_char) -> *const Ivar;
+    pub fn class_copyMethodList(cls: *const Class, outCount: *mut c_uint) -> *mut *const Method;
+    pub fn class_copyIvarList(cls: *const Class, outCount: *mut c_uint) -> *mut *const Ivar;
+    pub fn class_addMethod(cls: *mut Class, name: Sel, imp: Imp, types: *const c_char) -> BOOL;
+    pub fn class_addIvar(cls: *mut Class, name: *const c_char, size: usize, alignment: u8, types: *const c_char) -> BOOL;
+    pub fn class_addProtocol(cls: *mut Class, proto: *const Protocol) -> BOOL;
+    pub fn class_conformsToProtocol(cls: *const Class, proto: *const Protocol) -> BOOL;
+    pub fn class_copyProtocolList(cls: *const Class, outCount: *mut c_uint) -> *mut *const Protocol;
+
+    pub fn objc_allocateClassPair(superclass: *const Class, name: *const c_char, extraBytes: usize) -> *mut Class;
+    pub fn objc_disposeClassPair(cls: *mut Class);
+    pub fn objc_registerClassPair(cls: *mut Class);
+
+    pub fn class_createInstance(cls: *const Class, extraBytes: usize) -> *mut Object;
+    pub fn object_dispose(obj: *mut Object) -> *mut Object;
+    pub fn object_getClass(obj: *const Object) -> *const Class;
+
+    pub fn objc_getClassList(buffer: *mut *const Class, bufferLen: c_int) -> c_int;
+    pub fn objc_copyClassList(outCount: *mut c_uint) -> *mut *const Class;
+    pub fn objc_getClass(name: *const c_char) -> *const Class;
+    pub fn objc_getProtocol(name: *const c_char) -> *const Protocol;
+    pub fn objc_copyProtocolList(outCount: *mut c_uint) -> *mut *const Protocol;
+    pub fn objc_allocateProtocol(name: *const c_char) -> *mut Protocol;
+    pub fn objc_registerProtocol(proto: *mut Protocol);
+
+    pub fn objc_autoreleasePoolPush() -> *mut c_void;
+    pub fn objc_autoreleasePoolPop(context: *mut c_void);
+
+    pub fn protocol_addMethodDescription(proto: *mut Protocol, name: Sel, types: *const c_char, isRequiredMethod: BOOL,
+                                         isInstanceMethod: BOOL);
+    pub fn protocol_addProtocol(proto: *mut Protocol, addition: *const Protocol);
+    pub fn protocol_getName(proto: *const Protocol) -> *const c_char;
+    pub fn protocol_isEqual(proto: *const Protocol, other: *const Protocol) -> BOOL;
+    pub fn protocol_copyProtocolList(proto: *const Protocol, outCount: *mut c_uint) -> *mut *const Protocol;
+    pub fn protocol_conformsToProtocol(proto: *const Protocol, other: *const Protocol) -> BOOL;
+
+    pub fn ivar_getName(ivar: *const Ivar) -> *const c_char;
+    pub fn ivar_getOffset(ivar: *const Ivar) -> isize;
+    pub fn ivar_getTypeEncoding(ivar: *const Ivar) -> *const c_char;
+
+    pub fn method_getName(method: *const Method) -> Sel;
+    pub fn method_getImplementation(method: *const Method) -> Imp;
+    pub fn method_copyReturnType(method: *const Method) -> *mut c_char;
+    pub fn method_copyArgumentType(method: *const Method, index: c_uint) -> *mut c_char;
+    pub fn method_getNumberOfArguments(method: *const Method) -> c_uint;
+    pub fn method_setImplementation(method: *mut Method, imp: Imp) -> Imp;
+    pub fn method_exchangeImplementations(m1: *mut Method, m2: *mut Method);
+
+    pub fn objc_retain(obj: *mut Object) -> *mut Object;
+    pub fn objc_release(obj: *mut Object);
+    pub fn objc_autorelease(obj: *mut Object);
+
+    pub fn objc_loadWeakRetained(location: *mut *mut Object) -> *mut Object;
+    pub fn objc_initWeak(location: *mut *mut Object, obj: *mut Object) -> *mut Object;
+    pub fn objc_destroyWeak(location: *mut *mut Object);
+    pub fn objc_copyWeak(to: *mut *mut Object, from: *mut *mut Object);
+}
+
+impl Sel {
+    /// Registers a method with the Objective-C runtime system,
+    /// maps the method name to a selector, and returns the selector value.
+    pub fn register(name: &str) -> Sel {
+        let name = CString::new(name).unwrap();
+        unsafe {
+            sel_registerName(name.as_ptr())
+        }
+    }
+
+    /// Returns the name of the method specified by self.
+    pub fn name(&self) -> &str {
+        let name = unsafe {
+            CStr::from_ptr(sel_getName(*self))
+        };
+        str::from_utf8(name.to_bytes()).unwrap()
+    }
+
+    /// Wraps a raw pointer to a selector into a `Sel` object.
+    ///
+    /// This is almost never what you want; use `Sel::register()` instead.
+    #[inline]
+    pub unsafe fn from_ptr(ptr: *const c_void) -> Sel {
+        Sel {
+            ptr: ptr,
+        }
+    }
+
+    /// Returns a pointer to the raw selector.
+    #[inline]
+    pub fn as_ptr(&self) -> *const c_void {
+        self.ptr
+    }
+}
+
+impl PartialEq for Sel {
+    fn eq(&self, other: &Sel) -> bool {
+        self.ptr == other.ptr
+    }
+}
+
+impl Eq for Sel { }
+
+// Sel is safe to share across threads because it is immutable
+unsafe impl Sync for Sel { }
+unsafe impl Send for Sel { }
+
+impl Copy for Sel { }
+
+impl Clone for Sel {
+    fn clone(&self) -> Sel { *self }
+}
+
+impl fmt::Debug for Sel {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.name())
+    }
+}
+
+impl Ivar {
+    /// Returns the name of self.
+    pub fn name(&self) -> &str {
+        let name = unsafe {
+            CStr::from_ptr(ivar_getName(self))
+        };
+        str::from_utf8(name.to_bytes()).unwrap()
+    }
+
+    /// Returns the offset of self.
+    pub fn offset(&self) -> isize {
+        let offset = unsafe {
+            ivar_getOffset(self)
+        };
+        offset as isize
+    }
+
+    /// Returns the `Encoding` of self.
+    pub fn type_encoding(&self) -> Encoding {
+        let encoding = unsafe {
+            CStr::from_ptr(ivar_getTypeEncoding(self))
+        };
+        let s = str::from_utf8(encoding.to_bytes()).unwrap();
+        encode::from_str(s)
+    }
+}
+
+impl Method {
+    /// Returns the name of self.
+    pub fn name(&self) -> Sel {
+        unsafe {
+            method_getName(self)
+        }
+    }
+
+    /// Returns the `Encoding` of self's return type.
+    pub fn return_type(&self) -> Encoding {
+        unsafe {
+            let encoding = method_copyReturnType(self);
+            encode::from_malloc_str(encoding)
+        }
+    }
+
+    /// Returns the `Encoding` of a single parameter type of self, or
+    /// `None` if self has no parameter at the given index.
+    pub fn argument_type(&self, index: usize) -> Option<Encoding> {
+        unsafe {
+            let encoding = method_copyArgumentType(self, index as c_uint);
+            if encoding.is_null() {
+                None
+            } else {
+                Some(encode::from_malloc_str(encoding))
+            }
+        }
+    }
+
+    /// Returns the number of arguments accepted by self.
+    pub fn arguments_count(&self) -> usize {
+        unsafe {
+            method_getNumberOfArguments(self) as usize
+        }
+    }
+
+    /// Returns the implementation of self.
+    pub fn implementation(&self) -> Imp {
+        unsafe {
+            method_getImplementation(self)
+        }
+    }
+}
+
+impl Class {
+    /// Returns the class definition of a specified class, or `None` if the
+    /// class is not registered with the Objective-C runtime.
+    pub fn get(name: &str) -> Option<&'static Class> {
+        let name = CString::new(name).unwrap();
+        unsafe {
+            let cls = objc_getClass(name.as_ptr());
+            if cls.is_null() { None } else { Some(&*cls) }
+        }
+    }
+
+    /// Obtains the list of registered class definitions.
+    pub fn classes() -> MallocBuffer<&'static Class> {
+        unsafe {
+            let mut count: c_uint = 0;
+            let classes = objc_copyClassList(&mut count);
+            MallocBuffer::new(classes as *mut _, count as usize).unwrap()
+        }
+    }
+
+    /// Returns the total number of registered classes.
+    pub fn classes_count() -> usize {
+        unsafe {
+            objc_getClassList(ptr::null_mut(), 0) as usize
+        }
+    }
+
+    /// Returns the name of self.
+    pub fn name(&self) -> &str {
+        let name = unsafe {
+            CStr::from_ptr(class_getName(self))
+        };
+        str::from_utf8(name.to_bytes()).unwrap()
+    }
+
+    /// Returns the superclass of self, or `None` if self is a root class.
+    pub fn superclass(&self) -> Option<&Class> {
+        unsafe {
+            let superclass = class_getSuperclass(self);
+            if superclass.is_null() { None } else { Some(&*superclass) }
+        }
+    }
+
+    /// Returns the metaclass of self.
+    pub fn metaclass(&self) -> &Class {
+        unsafe {
+            let self_ptr: *const Class = self;
+            &*object_getClass(self_ptr as *const Object)
+        }
+    }
+
+    /// Returns the size of instances of self.
+    pub fn instance_size(&self) -> usize {
+        unsafe {
+            class_getInstanceSize(self) as usize
+        }
+    }
+
+    /// Returns a specified instance method for self, or `None` if self and
+    /// its superclasses do not contain an instance method with the
+    /// specified selector.
+    pub fn instance_method(&self, sel: Sel) -> Option<&Method> {
+        unsafe {
+            let method = class_getInstanceMethod(self, sel);
+            if method.is_null() { None } else { Some(&*method) }
+        }
+    }
+
+    /// Returns the ivar for a specified instance variable of self, or `None`
+    /// if self has no ivar with the given name.
+    pub fn instance_variable(&self, name: &str) -> Option<&Ivar> {
+        let name = CString::new(name).unwrap();
+        unsafe {
+            let ivar = class_getInstanceVariable(self, name.as_ptr());
+            if ivar.is_null() { None } else { Some(&*ivar) }
+        }
+    }
+
+    /// Describes the instance methods implemented by self.
+    pub fn instance_methods(&self) -> MallocBuffer<&Method> {
+        unsafe {
+            let mut count: c_uint = 0;
+            let methods = class_copyMethodList(self, &mut count);
+            MallocBuffer::new(methods as *mut _, count as usize).unwrap()
+        }
+
+    }
+
+    /// Checks whether this class conforms to the specified protocol.
+    pub fn conforms_to(&self, proto: &Protocol) -> bool {
+        unsafe { class_conformsToProtocol(self, proto) == YES }
+    }
+
+    /// Get a list of the protocols to which this class conforms.
+    pub fn adopted_protocols(&self) -> MallocBuffer<&Protocol> {
+        unsafe {
+            let mut count: c_uint = 0;
+            let protos = class_copyProtocolList(self, &mut count);
+            MallocBuffer::new(protos as *mut _, count as usize).unwrap()
+        }
+    }
+
+    /// Describes the instance variables declared by self.
+    pub fn instance_variables(&self) -> MallocBuffer<&Ivar> {
+        unsafe {
+            let mut count: c_uint = 0;
+            let ivars = class_copyIvarList(self, &mut count);
+            MallocBuffer::new(ivars as *mut _, count as usize).unwrap()
+        }
+    }
+}
+
+impl PartialEq for Class {
+    fn eq(&self, other: &Class) -> bool {
+        let self_ptr: *const Class = self;
+        let other_ptr: *const Class = other;
+        self_ptr == other_ptr
+    }
+}
+
+impl Eq for Class { }
+
+impl fmt::Debug for Class {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.name())
+    }
+}
+
+impl Protocol {
+    /// Returns the protocol definition of a specified protocol, or `None` if the
+    /// protocol is not registered with the Objective-C runtime.
+    pub fn get(name: &str) -> Option<&'static Protocol> {
+        let name = CString::new(name).unwrap();
+        unsafe {
+            let proto = objc_getProtocol(name.as_ptr());
+            if proto.is_null() { None } else { Some(&*proto) }
+        }
+    }
+
+    /// Obtains the list of registered protocol definitions.
+    pub fn protocols() -> MallocBuffer<&'static Protocol> {
+        unsafe {
+            let mut count: c_uint = 0;
+            let protocols = objc_copyProtocolList(&mut count);
+            MallocBuffer::new(protocols as *mut _, count as usize).unwrap()
+        }
+    }
+
+    /// Get a list of the protocols to which this protocol conforms.
+    pub fn adopted_protocols(&self) -> MallocBuffer<&Protocol> {
+        unsafe {
+            let mut count: c_uint = 0;
+            let protocols = protocol_copyProtocolList(self, &mut count);
+            MallocBuffer::new(protocols as *mut _, count as usize).unwrap()
+        }
+    }
+
+    /// Checks whether this protocol conforms to the specified protocol.
+    pub fn conforms_to(&self, proto: &Protocol) -> bool {
+        unsafe { protocol_conformsToProtocol(self, proto) == YES }
+    }
+
+    /// Returns the name of self.
+    pub fn name(&self) -> &str {
+        let name = unsafe {
+            CStr::from_ptr(protocol_getName(self))
+        };
+        str::from_utf8(name.to_bytes()).unwrap()
+    }
+}
+
+impl PartialEq for Protocol {
+    fn eq(&self, other: &Protocol) -> bool {
+        unsafe { protocol_isEqual(self, other) == YES }
+    }
+}
+
+impl Eq for Protocol { }
+
+impl fmt::Debug for Protocol {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.name())
+    }
+}
+
+impl Object {
+    /// Returns the class of self.
+    pub fn class(&self) -> &Class {
+        unsafe {
+            &*object_getClass(self)
+        }
+    }
+
+    /// Returns a reference to the ivar of self with the given name.
+    /// Panics if self has no ivar with the given name.
+    /// Unsafe because the caller must ensure that the ivar is actually
+    /// of type `T`.
+    pub unsafe fn get_ivar<T>(&self, name: &str) -> &T where T: Encode {
+        let offset = {
+            let cls = self.class();
+            match cls.instance_variable(name) {
+                Some(ivar) => {
+                    assert!(ivar.type_encoding() == T::encode());
+                    ivar.offset()
+                }
+                None => panic!("Ivar {} not found on class {:?}", name, cls),
+            }
+        };
+        let ptr = {
+            let self_ptr: *const Object = self;
+            (self_ptr as *const u8).offset(offset) as *const T
+        };
+        &*ptr
+    }
+
+    /// Returns a mutable reference to the ivar of self with the given name.
+    /// Panics if self has no ivar with the given name.
+    /// Unsafe because the caller must ensure that the ivar is actually
+    /// of type `T`.
+    pub unsafe fn get_mut_ivar<T>(&mut self, name: &str) -> &mut T
+            where T: Encode {
+        let offset = {
+            let cls = self.class();
+            match cls.instance_variable(name) {
+                Some(ivar) => {
+                    assert!(ivar.type_encoding() == T::encode());
+                    ivar.offset()
+                }
+                None => panic!("Ivar {} not found on class {:?}", name, cls),
+            }
+        };
+        let ptr = {
+            let self_ptr: *mut Object = self;
+            (self_ptr as *mut u8).offset(offset) as *mut T
+        };
+        &mut *ptr
+    }
+
+    /// Sets the value of the ivar of self with the given name.
+    /// Panics if self has no ivar with the given name.
+    /// Unsafe because the caller must ensure that the ivar is actually
+    /// of type `T`.
+    pub unsafe fn set_ivar<T>(&mut self, name: &str, value: T)
+            where T: Encode {
+        *self.get_mut_ivar::<T>(name) = value;
+    }
+}
+
+impl fmt::Debug for Object {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "<{:?}: {:p}>", self.class(), self)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils;
+    use Encode;
+    use super::{Class, Protocol, Sel};
+
+    #[test]
+    fn test_ivar() {
+        let cls = test_utils::custom_class();
+        let ivar = cls.instance_variable("_foo").unwrap();
+        assert!(ivar.name() == "_foo");
+        assert!(ivar.type_encoding() == <u32>::encode());
+        assert!(ivar.offset() > 0);
+
+        let ivars = cls.instance_variables();
+        assert!(ivars.len() > 0);
+    }
+
+    #[test]
+    fn test_method() {
+        let cls = test_utils::custom_class();
+        let sel = Sel::register("foo");
+        let method = cls.instance_method(sel).unwrap();
+        assert!(method.name().name() == "foo");
+        assert!(method.arguments_count() == 2);
+        assert!(method.return_type() == <u32>::encode());
+        assert!(method.argument_type(1).unwrap() == Sel::encode());
+
+        let methods = cls.instance_methods();
+        assert!(methods.len() > 0);
+    }
+
+    #[test]
+    fn test_class() {
+        let cls = test_utils::custom_class();
+        assert!(cls.name() == "CustomObject");
+        assert!(cls.instance_size() > 0);
+        assert!(cls.superclass().is_none());
+
+        assert!(Class::get(cls.name()) == Some(cls));
+
+        let metaclass = cls.metaclass();
+        // The metaclass of a root class is a subclass of the root class
+        assert!(metaclass.superclass().unwrap() == cls);
+
+        let subclass = test_utils::custom_subclass();
+        assert!(subclass.superclass().unwrap() == cls);
+    }
+
+    #[test]
+    fn test_classes() {
+        assert!(Class::classes_count() > 0);
+        let classes = Class::classes();
+        assert!(classes.len() > 0);
+    }
+
+    #[test]
+    fn test_protocol() {
+        let proto = test_utils::custom_protocol();
+        assert!(proto.name() == "CustomProtocol");
+        let class = test_utils::custom_class();
+        assert!(class.conforms_to(proto));
+        let class_protocols = class.adopted_protocols();
+        assert!(class_protocols.len() > 0);
+    }
+
+    #[test]
+    fn test_protocol_method() {
+        let class = test_utils::custom_class();
+        let result: i32 = unsafe {
+            msg_send![class, addNumber:1 toNumber:2]
+        };
+        assert_eq!(result, 3);
+    }
+
+    #[test]
+    fn test_subprotocols() {
+        let sub_proto = test_utils::custom_subprotocol();
+        let super_proto = test_utils::custom_protocol();
+        assert!(sub_proto.conforms_to(super_proto));
+        let adopted_protocols = sub_proto.adopted_protocols();
+        assert_eq!(adopted_protocols[0], super_proto);
+    }
+
+    #[test]
+    fn test_protocols() {
+        // Ensure that a protocol has been registered on linux
+        let _ = test_utils::custom_protocol();
+
+        let protocols = Protocol::protocols();
+        assert!(protocols.len() > 0);
+    }
+
+    #[test]
+    fn test_object() {
+        let mut obj = test_utils::custom_object();
+        assert!(obj.class() == test_utils::custom_class());
+        let result: u32 = unsafe {
+            obj.set_ivar("_foo", 4u32);
+            *obj.get_ivar("_foo")
+        };
+        assert!(result == 4);
+    }
+}
diff --git a/third_party/rust/objc/src/test_utils.rs b/third_party/rust/objc/src/test_utils.rs
new file mode 100644
index 0000000000..873f82f6b1
--- /dev/null
+++ b/third_party/rust/objc/src/test_utils.rs
@@ -0,0 +1,187 @@
+use std::ops::{Deref, DerefMut};
+use std::os::raw::c_char;
+use std::sync::{Once, ONCE_INIT};
+
+use declare::{ClassDecl, ProtocolDecl};
+use runtime::{Class, Object, Protocol, Sel, self};
+use {Encode, Encoding};
+
+pub struct CustomObject {
+    obj: *mut Object,
+}
+
+impl CustomObject {
+    fn new(class: &Class) -> Self {
+        let obj = unsafe {
+            runtime::class_createInstance(class, 0)
+        };
+        CustomObject { obj: obj }
+    }
+}
+
+impl Deref for CustomObject {
+    type Target = Object;
+
+    fn deref(&self) -> &Object {
+        unsafe { &*self.obj }
+    }
+}
+
+impl DerefMut for CustomObject {
+    fn deref_mut(&mut self) -> &mut Object {
+        unsafe { &mut *self.obj }
+    }
+}
+
+impl Drop for CustomObject {
+    fn drop(&mut self) {
+        unsafe {
+            runtime::object_dispose(self.obj);
+        }
+    }
+}
+
+#[derive(Eq, PartialEq)]
+pub struct CustomStruct {
+    pub a: u64,
+    pub b: u64,
+    pub c: u64,
+    pub d: u64,
+}
+
+unsafe impl Encode for CustomStruct {
+    fn encode() -> Encoding {
+        let mut code = "{CustomStruct=".to_owned();
+        for _ in 0..4 {
+            code.push_str(u64::encode().as_str());
+        }
+        code.push_str("}");
+        unsafe {
+            Encoding::from_str(&code)
+        }
+    }
+}
+
+pub fn custom_class() -> &'static Class {
+    static REGISTER_CUSTOM_CLASS: Once = ONCE_INIT;
+
+    REGISTER_CUSTOM_CLASS.call_once(|| {
+        // The runtime will call this method, so it has to be implemented
+        extern fn custom_obj_class_initialize(_this: &Class, _cmd: Sel) { }
+
+        let mut decl = ClassDecl::root("CustomObject", custom_obj_class_initialize).unwrap();
+        let proto = custom_protocol();
+
+        decl.add_protocol(proto);
+        decl.add_ivar::<u32>("_foo");
+
+        extern fn custom_obj_set_foo(this: &mut Object, _cmd: Sel, foo: u32) {
+            unsafe { this.set_ivar::<u32>("_foo", foo); }
+        }
+
+        extern fn custom_obj_get_foo(this: &Object, _cmd: Sel) -> u32 {
+            unsafe { *this.get_ivar::<u32>("_foo") }
+        }
+
+        extern fn custom_obj_get_struct(_this: &Object, _cmd: Sel) -> CustomStruct {
+            CustomStruct { a: 1, b: 2, c: 3, d: 4 }
+        }
+
+        extern fn custom_obj_class_method(_this: &Class, _cmd: Sel) -> u32 {
+            7
+        }
+
+        extern fn custom_obj_set_bar(this: &mut Object, _cmd: Sel, bar: u32) {
+            unsafe { this.set_ivar::<u32>("_foo", bar) ;}
+        }
+
+        extern fn custom_obj_add_number_to_number(_this: &Class, _cmd: Sel, fst: i32, snd: i32) -> i32 {
+            fst + snd
+        }
+
+        unsafe {
+            let set_foo: extern fn(&mut Object, Sel, u32) = custom_obj_set_foo;
+            decl.add_method(sel!(setFoo:), set_foo);
+            let get_foo: extern fn(&Object, Sel) -> u32 = custom_obj_get_foo;
+            decl.add_method(sel!(foo), get_foo);
+            let get_struct: extern fn(&Object, Sel) -> CustomStruct = custom_obj_get_struct;
+            decl.add_method(sel!(customStruct), get_struct);
+            let class_method: extern fn(&Class, Sel) -> u32 = custom_obj_class_method;
+            decl.add_class_method(sel!(classFoo), class_method);
+
+            let protocol_instance_method: extern fn(&mut Object, Sel, u32) = custom_obj_set_bar;
+            decl.add_method(sel!(setBar:), protocol_instance_method);
+            let protocol_class_method: extern fn(&Class, Sel, i32, i32) -> i32 = custom_obj_add_number_to_number;
+            decl.add_class_method(sel!(addNumber:toNumber:), protocol_class_method);
+        }
+
+        decl.register();
+    });
+
+    class!(CustomObject)
+}
+
+pub fn custom_protocol() -> &'static Protocol {
+    static REGISTER_CUSTOM_PROTOCOL: Once = ONCE_INIT;
+
+    REGISTER_CUSTOM_PROTOCOL.call_once(|| {
+        let mut decl = ProtocolDecl::new("CustomProtocol").unwrap();
+
+        decl.add_method_description::<(i32,), ()>(sel!(setBar:), true);
+        decl.add_method_description::<(), *const c_char>(sel!(getName), false);
+        decl.add_class_method_description::<(i32, i32), i32>(sel!(addNumber:toNumber:), true);
+
+        decl.register();
+    });
+
+    Protocol::get("CustomProtocol").unwrap()
+}
+
+pub fn custom_subprotocol() -> &'static Protocol {
+    static REGISTER_CUSTOM_SUBPROTOCOL: Once = ONCE_INIT;
+
+    REGISTER_CUSTOM_SUBPROTOCOL.call_once(|| {
+        let super_proto = custom_protocol();
+        let mut decl = ProtocolDecl::new("CustomSubProtocol").unwrap();
+
+        decl.add_protocol(super_proto);
+        decl.add_method_description::<(u32,), u32>(sel!(calculateFoo:), true);
+
+        decl.register();
+    });
+
+    Protocol::get("CustomSubProtocol").unwrap()
+}
+
+pub fn custom_object() -> CustomObject {
+    CustomObject::new(custom_class())
+}
+
+pub fn custom_subclass() -> &'static Class {
+    static REGISTER_CUSTOM_SUBCLASS: Once = ONCE_INIT;
+
+    REGISTER_CUSTOM_SUBCLASS.call_once(|| {
+        let superclass = custom_class();
+        let mut decl = ClassDecl::new("CustomSubclassObject", superclass).unwrap();
+
+        extern fn custom_subclass_get_foo(this: &Object, _cmd: Sel) -> u32 {
+            let foo: u32 = unsafe {
+                msg_send![super(this, custom_class()), foo]
+            };
+            foo + 2
+        }
+
+        unsafe {
+            let get_foo: extern fn(&Object, Sel) -> u32 = custom_subclass_get_foo;
+            decl.add_method(sel!(foo), get_foo);
+        }
+
+        decl.register();
+    });
+
+    class!(CustomSubclassObject)
+}
+
+pub fn custom_subclass_object() -> CustomObject {
+    CustomObject::new(custom_subclass())
+}