http://www.robohornet.org gives a score of 101.36 on master, and 102.68 with this PR. The latter is slightly better, but probably within noise level. So it looks like this PR does not affect DOM performance.
This is expected since `Box::new` is defined as:
```rust
impl<T> Box<T> {
#[inline(always)]
pub fn new(x: T) -> Box<T> {
box x
}
}
```
With inlining, it should compile to the same as box syntax.
Source-Repo: https://github.com/servo/servo
Source-Revision: a9022be0c3e30249845ca5947ac0c0a6743c7991
--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 97a17674f72dbfcb99552fe4877789f149ccfc84
Globals in that PR are now represented by the fake IDL interface `GlobalScope`.
Source-Repo: https://github.com/servo/servo
Source-Revision: a6e4b5bb86ad707a0863acff87344ca4239cfd2c
--HG--
rename : servo/components/script/dom/webidls/ServoXMLParser.webidl => servo/components/script/dom/webidls/GlobalScope.webidl
Expands on the work by @wilmoz and cleans up the existing errors. Closes#7180. Closes#7111.
Source-Repo: https://github.com/servo/servo
Source-Revision: e74825f9fde8e222f4ba9bb24b2c2a3864c73e5f
Also adds HeapSizeOf implementations/derive for some types. I've used "Cannot calculate Heap size" as a reason everywhere, because my imagination is rather limited. If you'd like me to change this message for specific types, please write something like this: "Trusted - Cannot calculate Heap size for Trusted" so that it would be easier for me to replace them through a script :)
Source-Repo: https://github.com/servo/servo
Source-Revision: a03616f379c255cc6c9b6e1d04dd7d98bd9926ce
> Here it is.
>
> ~~There's two major things that are unfinished here:~~
> - ~~Dealing with the unroot_must_root lint. I'm not sure about the value of this lint with the new rooting API.~~ Done.
> - ~~Updating the Cargo.locks to point to the new SM and SM binding.~~ Done.
>
> I also included my fixes for the rust update, but these will disappear in a rebase. A rust update is necessary to support calling `Drop` on `Heap<T>` correctly when `Heap<T>` is inside a `Rc<T>`. Otherwise `&self` points to the wrong location.
>
> Incremental GC is disabled here. I'm not sure how to deal with the incremental barriers so that's left for later.
>
> Generational GC works. SM doesn't work without it.
>
> The biggest change here is to the rooting API. `Root` was made movable, and `Temporary` and `JSRef` was removed. Movable `Root`s means there's no need for `Temporary`, and `JSRef`s aren't needed generally since it can be assumed that being able to obtain a reference to a dom object means it's already rooted. References have their lifetime bound to the Roots that provided them. DOM objects that haven't passed through `reflect_dom_object` don't need to be rooted, and DOM objects that have passed through `reflect_dom_object` can't be obtained without being rooted through `native_from_reflector_jsmanaged` or `JS::<T>::root()`.
>
> Support for `Heap<T>` ended up messier than I expected. It's split into two commits, but only because it's a bit difficult to fold them together. Supporting `Heap<T>` properly requires that that `Heap::<T>::set()` be called on something that won't move. I removed the Copy and Clone trait from `Heap<T>` so `Cell` can't hold `Heap<T>` - only `UnsafeCell` can hold it.
>
> `CallbackObject` is a bit tricky - I moved all callbacks into `Rc<T>` in order to make sure that the pointer inside to a `*mut JSObject` doesn't move. This is necessary for supporting `Heap<T>`.
>
> `RootedCollectionSet` is very general purpose now. Anything with `JSTraceable` can be rooted by `RootedCollectionSet`/`RootedTraceable`. Right now, `RootedTraceable` is only used to hold down dom objects before they're fully attached to their reflector. I had to make a custom mechanism to dispatch the trace call - couldn't figure out how to get trait objects working for this case.
>
> This has been tested with the following zeal settings:
>
> GC after every allocation
> JS_GC_ZEAL=2,1
>
> GC after every 100 allocations (important for catching use-after-free bugs)
> JS_GC_ZEAL=2,100
>
> Verify pre barriers
> JS_GC_ZEAL=4,1
>
> Verify post barriers
> JS_GC_ZEAL=11,1
Source-Repo: https://github.com/servo/servo
Source-Revision: e7808c526c348fea5e3b48af70b7f1a066652097
