Since LLVM doesn't vectorize the loop for us, do unaligned reads
of a larger type and use LLVM's bswap intrinsic to do the
reversing of the actual bytes. cfg!-restricted to x86 and
x86_64, as I assume it wouldn't help on things like ARMv5.
Also makes [u16]::reverse() a more modest 1.5x faster by
loading/storing u32 and swapping the u16s with ROT16.
Thank you ptr::*_unaligned for making this easy :)
Major difference is that I removed Deref impls, as apparently LLVM has
trouble maintaining metadata with a `&ptr -> &ptr` API. This was cited
as a blocker for ever stabilizing this API. It wasn't that ergonomic
anyway.
* Added `get` to NonZero to replace Deref impl
* Added `as_ptr` to Shared/Unique to replace Deref impl
* Added Unique's `as_ref` and `as_mut` conveniences to Shared
* Added `::empty()` convenience constructor for Unique/Shared
* Deprecated `as_mut_ptr` on Shared in favour of `as_ptr`
* Improved documentation of types
Note that Shared now only refers to *mut, and not *const
process:exit -> process::exit in mem::forget docs
The documentation in mem::forget says "...or call `process:exit`..."
instead of `process::exit`.
r? @steveklabnik
reduce stack requirements for floating-point formatting
Doing this speeds up float formatting by ~10% or so, and also makes the formatting code more suitable for embedded environments where stack space is at a premium.
We've got a freshly minted beta compiler, let's update to use that on nightly!
This has a few other changes associated with it as well
* A bump to the rustc version number (to 1.19.0)
* Movement of the `cargo` and `rls` submodules to their "proper" location in
`src/tools/{cargo,rls}`. Now that Cargo workspaces support the `exclude`
option this can work.
* Updates of the `cargo` and `rls` submodules to their master branches.
* Tweak to the `src/stage0.txt` format to be more amenable for Cargo version
numbers. On the beta channel Cargo will bootstrap from a different version
than rustc (e.g. the version numbers are different), so we need different
configuration for this.
* Addition of `dev` as a readable key in the `src/stage0.txt` format. If present
then stage0 compilers are downloaded from `dev-static.rust-lang.org` instead
of `static.rust-lang.org`. This is added to accomodate our updated release
process with Travis and AppVeyor.
The comments for flt2dec::to_shortest_str says that we only need a slice
of length 5 for the parts array. Initializing a 16-part array is just
wasted effort and wasted stack space. Other functions in the flt2dec
module have similar comments, so we adjust the parts arrays passed to
those functions accordingly.
For the two major entry points for float formatting, we split the exact
case and the shortest cases into separate functions. We mark the
separate functions as #[inline(never) so the exact cases won't bloat
stack space in their callers unnecessarily. The shortest cases are
marked so for similar reasons.
Fixes#41234.
We have benchmarks for the floating-point formatting algorithms
themselves, but not for the surrounding machinery like Formatter and
translating to the flt2dec::Part slices.
rustc: replace TypeContents with two independent properties (is_freeze / needs_drop).
`InteriorUnsafe` / `interior_unsafe` was replaced with a private lang-item `Freeze` auto trait in libcore.
`OwnsDtor` / `needs_drop` was replaced with a specialized traversal that *doesn't* avoid caching results in case of a cycle, as the only cycles left can only occur in erroneous "types with infinite sizes", references and raw pointers not having destructors. Also, `Copy` is now checked at every step of the recursion.
r? @nikomatsakis
Rename compiler_barrier to compiler_fence
This addresses concerns raised following the merge of #41092. Specifically:
> The naming of these seems surprising: the multithreaded functions (and both the single and multithreaded intrinsics themselves) are fences, but this is a barrier. It's not incorrect, but the latter is both inconsistent with the existing functions and slightly confusing with another type in std (e.g., `Barrier`).
`compiler_fence` carries the same semantic implication that this is a compiler-only operation, while being more in line with the fence/barrier concepts already in use in `std`.
Improve std::hash docs
Fixes#29357.
For details on what exactly I've done, see the commit descriptions.
There are some things I'm not sure about, but would like to address before merging this so the issue can be closed; any feedback on these points would really be appriciated:
* [x] ~I didn't touch the module level docs at all. On the one hand, I think they could use a short overview over the module; on the other hand, the module really isn't that big and I don't know if I could really do anything beyond just duplicating the type's summaries...~
* [x] ~I feel like the module-level examples are quite long-winded and not to the point, but I couldn't really think of anything better. Any ideas?~
* [x] ~Should `Hasher` get an example for implementing it? There is one in the module documentation, but it only "implements" it via `unimplemented!` and I'm not sure what the value of that is.~
* [x] ~Should `Hasher`'s `write_{int}` methods get examples?~
If there's anything else you'd like to see in std::hash's docs, please let me know!
r? @rust-lang/docs
This addresses concerns raised following the merge of #41092.
Specifically:
> The naming of these seems surprising: the multithreaded functions (and
> both the single and multithreaded intrinsics themselves) are fences,
> but this is a barrier. It's not incorrect, but the latter is both
> inconsistent with the existing functions and slightly confusing with
> another type in std (e.g., `Barrier`).
`compiler_fence` carries the same semantic implication that this is a
compiler-only operation, while being more in line with the fence/barrier
concepts already in use in `std`.
