Background
==========
Slices currently have an unstable [`rotate`] method which rotates
elements in the slice to the _left_ N positions. [Here][tracking] is the
tracking issue for this unstable feature.
```rust
let mut a = ['a', 'b' ,'c', 'd', 'e', 'f'];
a.rotate(2);
assert_eq!(a, ['c', 'd', 'e', 'f', 'a', 'b']);
```
Proposal
========
Deprecate the [`rotate`] method and introduce `rotate_left` and
`rotate_right` methods.
```rust
let mut a = ['a', 'b' ,'c', 'd', 'e', 'f'];
a.rotate_left(2);
assert_eq!(a, ['c', 'd', 'e', 'f', 'a', 'b']);
```
```rust
let mut a = ['a', 'b' ,'c', 'd', 'e', 'f'];
a.rotate_right(2);
assert_eq!(a, ['e', 'f', 'a', 'b', 'c', 'd']);
```
Justification
=============
I used this method today for my first time and (probably because I’m a
naive westerner who reads LTR) was surprised when the docs mentioned that
elements get rotated in a left-ward direction. I was in a situation
where I needed to shift elements in a right-ward direction and had to
context switch from the main problem I was working on and think how much
to rotate left in order to accomplish the right-ward rotation I needed.
Ruby’s `Array.rotate` shifts left-ward, Python’s `deque.rotate` shifts
right-ward. Both of their implementations allow passing negative numbers
to shift in the opposite direction respectively.
Introducing `rotate_left` and `rotate_right` would:
- remove ambiguity about direction (alleviating need to read docs 😉)
- make it easier for people who need to rotate right
[`rotate`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rotate
[tracking]: https://github.com/rust-lang/rust/issues/41891
Convert warning about `*const _` to a future-compat lint
#46664 was merged before I could convert the soft warning about method lookup on `*const _` into a future-compatibility lint. This PR makes that change.
fixes#46837
tracking issue for the future-compatibility lint: #46906
r? @arielb1
rustc: Set release mode cgus to 16 by default
This commit is the next attempt to enable multiple codegen units by default in
release mode, getting some of those sweet, sweet parallelism wins by running
codegen in parallel. Performance should not be lost due to ThinLTO being on by
default as well.
Closes#45320
Set the dwarf linkage_name to the mangled name
ref #46453
@michaelwoerister or anyone else who knows, i'm not sure if this is the correct instance to pass here (or how to get the correct one precisely): 5a94a48678/src/librustc_trans/debuginfo/namespace.rs (L36)
So don't merge this yet, I'd like to learn about correct instance first; however, I think this already fixes a bunch of weirdness i'm seeing debugging from time to time, not to mention backtraces in gdb via `bt` are now ~readable~ meaningful 🎉
E.g.:
new:
```
(gdb) bt
#0 <inline::Foo as core::convert::From<()>>::from () at /home/m4b/tmp/bad_debug/inline.rs:11
#1 0x000055555555a35d in inline::deadbeef () at /home/m4b/tmp/bad_debug/inline.rs:16
#2 0x000055555555a380 in inline::main () at /home/m4b/tmp/bad_debug/inline.rs:20
```
old:
```
(gdb) bt
#0 inline::{{impl}}::from () at /home/m4b/tmp/bad_debug/inline.rs:11
#1 0x000055555555b0ed in inline::deadbeef () at /home/m4b/tmp/bad_debug/inline.rs:16
#2 0x000055555555b120 in inline::main () at /home/m4b/tmp/bad_debug/inline.rs:20
```
- Update example in ‘security’ section to use hard links, like the
linked securityvulns.com example.
- Weaken language on symbolic links – indicate behavior is
platform-specific
Fixes https://github.com/rust-lang/rust/issues/43617.
Prevent unwinding past FFI boundaries
Second attempt to write a patch to solve this.
r? @nikomatsakis
~~So, my biggest issue with this patch is the way the patch determines *what* functions should have an abort landing pad (in `construct_fn`). I would ideally have this code match [src/librustc_trans/callee.rs::get_fn](https://github.com/rust-lang/rust/blob/master/src/librustc_trans/callee.rs#L107-L115) but couldn't find an id that returns true for `is_foreign_item`. Also tried `tcx.has_attr("unwind")` with no luck.~~ FIXED
Other issues:
* llvm.trap is an SIGILL on amd64. Ideally we could use panic-abort's version of aborting which is nicer but we don't want to depend on that library...
* ~~Mir inlining is a stub currently.~~ FIXED (no-op)
Also, when reviewing please take into account that I'm new to the code and only partially know what I'm doing... and that I've mostly made made matches on `TerminatorKind::Abort` match either `TerminatorKind::Resume` or `TerminatorKind::Unreachable` based on what looked best.
This commit is the next attempt to enable multiple codegen units by default in
release mode, getting some of those sweet, sweet parallelism wins by running
codegen in parallel. Performance should not be lost due to ThinLTO being on by
default as well.
Closes#45320
Make the match exhaustive, adding handling for anonymous types and
tuple coercions on the way.
Also, exit early when type errors are detected, to avoid error cascades
and the like.
incr.comp.: Use an array instead of a hashmap for storing result hashes.
Doing so should result in some of the core tracking components being faster.
r? @nikomatsakis
Followup for #46112.
Sorting by crate-num should ensure that we favor `std::foo::bar` over
`any_other_crate::foo::bar`.
Interestingly, *this* change had a much larger impact on our internal
test suite than PR #46708 (which was my original fix to #46112).
Issue #46589 - Kill borrows on a local variable whenever we assign ov…
…er this variable
This is a first patch for the issue, handling the simple case while I figure out the data structures involved in the more complex cases.
