Split up ptr/mod.rs in libcore...
...one with implementation detail for const ptr and the other with mut ptr
I am not sure if the "stable since 1.0.0" flags are the correct choice for the two additional mods.
Also, is it necessary for them to be "pub"? If so, there should be a good description for them.
Closes#66891
Add more delegations to the fmt docs and add doctests
HI,
this is a continuation to #67021
I replaced the `Debug` example with one that use the `Debug*` helpers so that padding etc will work too.
I also added asserts for the doctests as @RalfJung asked :)
The only thing I left with the `write!` macro is the `Display` example as I didn't know if there's a better way to do that.
r? @QuietMisdreavus
Improve code generated for `starts_with(<literal char>)`
This PR includes two minor improvements to the code generated when checking for string prefix/suffix.
The first commit simplifies the str/str operation, by taking advantage of the raw UTF-8 representation.
The second commit replaces the current str/char matching logic with a char->str encoding and then the previous method.
The resulting code should be equivalent in the generic case (one char is being encoded versus one char being decoded), but it becomes easy to optimize in the case of a literal char, which in most cases a developer might expect to be at least as simple as that of a literal string.
This PR should fix#41993
Stabilize the `core::panic` module
`std::panic` is already stable.
`core::panic::PanicInfo` and `core::panic::Location` are stable and can be used through that path because of a bug in stability checking: #15702
Require stable/unstable annotations for the constness of all stable fns with a const modifier
r? @RalfJung @Centril
Every `#[stable]` const fn now needs either a `#[rustc_const_unstable]` attribute or a `#[rustc_const_stable]` attribute. You can't silently stabilize the constness of a function anymore.
The comparison can be performed on the raw bytes, as the chars can
only match if their UTF8 encoding matches.
This avoids the `is_char_boundary` checks and translates to a straight
`u8` slice comparison which is optimized to a memcmp or inline
comparison where appropriate.
async/await: improve not-send errors, part 2
Part of #64130. Fixes#65667.
This PR improves the errors introduced in #64895 so that they have specialized messages for `Send` and `Sync`.
r? @nikomatsakis
Optimize Ord trait implementation for bool
Casting the booleans to `i8`s and converting their difference into `Ordering` generates better assembly than casting them to `u8`s and comparing them.
Fixes#66780
#### Comparison([Godbolt link](https://rust.godbolt.org/z/PjBpvF))
##### Old assembly:
```asm
example::boolean_cmp:
mov ecx, edi
xor ecx, esi
test esi, esi
mov eax, 255
cmove eax, ecx
test edi, edi
cmovne eax, ecx
ret
```
##### New assembly:
```asm
example::boolean_cmp:
mov eax, edi
sub al, sil
ret
```
##### Old LLVM-MCA statistics:
```
Iterations: 100
Instructions: 800
Total Cycles: 234
Total uOps: 1000
Dispatch Width: 6
uOps Per Cycle: 4.27
IPC: 3.42
Block RThroughput: 1.7
```
##### New LLVM-MCA statistics:
```
Iterations: 100
Instructions: 300
Total Cycles: 110
Total uOps: 500
Dispatch Width: 6
uOps Per Cycle: 4.55
IPC: 2.73
Block RThroughput: 1.0
```
Use deref target in Pin trait implementations
Using deref target instead of pointer itself avoids providing access to `&Rc<T>` for malicious implementations, which would allow calling `Rc::get_mut`.
This is a breaking change necessary due to unsoundness, however the impact of it should be minimal.
This only fixes the issue with malicious `PartialEq` implementations, other `Pin` soundness issues are still here.
See <https://internals.rust-lang.org/t/unsoundness-in-pin/11311/73> for more details.
libstd miri tests: avoid warnings
Ignore tests in a way that all the code still gets compiled, to get rid of all the "unused" warnings that otherwise show up when running the test suite in Miri.
Format libcore with rustfmt (including tests and benches)
Important: two small non-rustfmt changes that will need close review:
- I added `#[rustfmt::skip]` to two manually arranged tables in src/libcore/benches/ascii.rs; see first commit in the PR.
- I added `// ignore-tidy-filelength` to src/libcore/ptr/mod.rs because rustfmt puts it over tidy's 3000 line limit; see second commit in the PR. I filed #66891 to follow up on breaking up that file. For now though having it be formatted is more important than having it below the line limit.
---
As with my previous formatting PRs, I am avoiding causing merge conflicts in other PRs by only touches those files that are not involved in any currently open PR. Files that appear in new PRs between when this PR is opened and when it makes it to the top of the bors queue will be reverted from this PR.
The list of files involved in open PRs is determined by querying GitHub's GraphQL API [with this script](https://gist.github.com/dtolnay/aa9c34993dc051a4f344d1b10e4487e8).
With the list of files from the script in outstanding_files, the relevant commands were:
```
$ find src/libcore -name '*.rs' \
| xargs rustfmt --edition=2018 --unstable-features --skip-children
$ rg libcore outstanding_files | xargs git checkout --
```
To confirm no funny business:
```
$ git checkout $THIS_COMMIT^
$ git show --pretty= --name-only $THIS_COMMIT \
| xargs rustfmt --edition=2018 --unstable-features --skip-children
$ git diff $THIS_COMMIT # there should be no difference
```
r? @Dylan-DPC
