Rollup of 14 pull requests #90119
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Rollup of 14 pull requests #90119
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The way octal literals are written in IP addresses differs from the way they are written in Rust code, so the way that octal/hex literals in IPs are written is explictly mentioned.
Now that there can't be a bunch of leading zeros, parsing can be optimized a bit.
Co-authored-by: Cheng XU <[email protected]>
Debug logging during incremental compilation had been broken for some time, until rust-lang#89343 fixed it (among other things). Add a test so this is less likely to break without being noticed. This test is nearly a copy of the `src/test/ui/rustc-rust-log.rs` test, but tests debug logging in the incremental compliation code paths.
I'm working on some LLVM patches in concert with a Rust patch, and it's helping me quite a bit to have this as an option. It doesn't seem that hard, so I figured I'd formalize it in x.py and send it upstream.
use array explicitly instead of vec for const content (even if optimizer smart enought to remove allocation)
…zer smart enought to remove allocation)
I also changed the feature gate added to `From` impls of Atomic integer to `const_num_from_num` from `const_convert`.
…d on foreign trait implementations
Co-authored-by: Yuki Okushi <[email protected]>
Reject octal zeros in IPv4 addresses This fixes rust-lang#86964 by rejecting octal zeros in IP addresses, such that `192.168.00.00000000` is rejected with a parse error, since having leading zeros in front of another zero indicates it is a zero written in octal notation, which is not allowed in the strict mode specified by RFC 6943 3.1.1. Octal rejection was implemented in rust-lang#83652, but due to the way it was implemented octal zeros were still allowed.
Remove unnecessary condition in Barrier::wait()
This is my first pull request for Rust, so feel free to call me out if anything is amiss.
After some examination, I realized that the second condition of the "spurious-wakeup-handler" loop in ``std::sync::Barrier::wait()`` should always evaluate to ``true``, making it redundant in the ``&&`` expression.
Here is the affected function before the fix:
```rust
#[stable(feature = "rust1", since = "1.0.0")]
pub fn wait(&self) -> BarrierWaitResult {
let mut lock = self.lock.lock().unwrap();
let local_gen = lock.generation_id;
lock.count += 1;
if lock.count < self.num_threads {
// We need a while loop to guard against spurious wakeups.
// https://en.wikipedia.org/wiki/Spurious_wakeup
while local_gen == lock.generation_id && lock.count < self.num_threads { // fixme
lock = self.cvar.wait(lock).unwrap();
}
BarrierWaitResult(false)
} else {
lock.count = 0;
lock.generation_id = lock.generation_id.wrapping_add(1);
self.cvar.notify_all();
BarrierWaitResult(true)
}
}
```
At first glance, it seems that the check that ``lock.count < self.num_threads`` would be necessary in order for a thread A to detect when another thread B has caused the barrier to reach its thread count, making thread B the "leader".
However, the control flow implicitly results in an invariant that makes observing ``!(lock.count < self.num_threads)``, i.e. ``lock.count >= self.num_threads`` impossible from thread A.
When thread B, which will be the leader, calls ``.wait()`` on this shared instance of the ``Barrier``, it locks the mutex in the first line and saves the ``MutexGuard`` in the ``lock`` variable. It then increments the value of ``lock.count``. However, it then proceeds to check if ``lock.count < self.num_threads``. Since it is the leader, it is the case that (after the increment of ``lock.count``), the lock count is *equal* to the number of threads. Thus, the second branch is immediately taken and ``lock.count`` is zeroed. Additionally, the generation ID is incremented (with wrap). Then, the condition variable is signalled. But, the other threads are waiting at the line ``lock = self.cvar.wait(lock).unwrap();``, so they cannot resume until thread B's call to ``Barrier::wait()`` returns, which drops the ``MutexGuard`` acquired in the first ``let`` statement and unlocks the mutex.
The order of events is thus:
1. A thread A calls `.wait()`
2. `.wait()` acquires the mutex, increments `lock.count`, and takes the first branch
3. Thread A enters the ``while`` loop since the generation ID has not changed and the count is less than the number of threads for the ``Barrier``
3. Spurious wakeups occur, but both conditions hold, so the thread A waits on the condition variable
4. This process repeats for N - 2 additional times for non-leader threads A'
5. *Meanwhile*, Thread B calls ``Barrier::wait()`` on the same barrier that threads A, A', A'', etc. are waiting on. The thread count reaches the number of threads for the ``Barrier``, so all threads should now proceed, with B being the leader. B acquires the mutex and increments the value ``lock.count`` only to find that it is not less than ``self.num_threads``. Thus, it immediately clamps ``self.num_threads`` back down to 0 and increments the generation. Then, it signals the condvar to tell the A (prime) threads that they may continue.
6. The A, A', A''... threads wake up and attempt to re-acquire the ``lock`` as per the internal operation of a condition variable. When each A has exclusive access to the mutex, it finds that ``lock.generation_id`` no longer matches ``local_generation`` **and the ``&&`` expression short-circuits -- and even if it were to evaluate it, ``self.count`` is definitely less than ``self.num_threads`` because it has been reset to ``0`` by thread B *before* B dropped its ``MutexGuard``**.
Therefore, it my understanding that it would be impossible for the non-leader threads to ever see the second boolean expression evaluate to anything other than ``true``. This PR simply removes that condition.
Any input would be appreciated. Sorry if this is terribly verbose. I'm new to the Rust community and concurrency can be hard to explain in words. Thanks!
`AbstractConst` private fields Calls `subst` in `AbstractConst::root` when `Node` is `Leaf`. r? ``@lcnr``
…_with_nul, r=JohnTitor Stabilize CString::from_vec_with_nul[_unchecked] Closes the tracking issue rust-lang#73179. I am keeping this in _draft_ mode until the FCP has ended. This is my first time stabilizing a feature, so I would appreciate any guidance on things I should do differently. Closes rust-lang#73179
…in_overflow, r=m-ou-se Avoid overflow in `VecDeque::with_capacity_in()`. The overflow only happens if alloc is compiled with overflow checks enabled and the passed capacity is greater or equal 2^(usize::BITS-1). The overflow shadows the expected "capacity overflow" panic leading to a test failure if overflow checks are enabled for std in the CI. Unblocks [CI: Enable overflow checks for test (non-dist) builds rust-lang#89776](rust-lang#89776). For some reason the overflow is only observable with optimization turned off, but that is a separate issue.
…t, r=Mark-Simulacrum Add test for debug logging during incremental compilation Debug logging during incremental compilation had been broken for some time, until rust-lang#89343 fixed it (among other things). Add a test so this is less likely to break without being noticed. This test is nearly a copy of the `src/test/ui/rustc-rust-log.rs` test, but tests debug logging in the incremental compliation code paths.
…mulacrum config: add the option to enable LLVM tests I'm working on some LLVM patches in concert with a Rust patch, and it's helping me quite a bit to have this as an option. It doesn't seem that hard, so I figured I'd formalize it in x.py and send it upstream.
… r=jsha Add test for line-number setting The first commit updates the version of the package to be able to have multi-line commands (which looks much nicer for this test). r? ````@jsha````
Remove hir::map::blocks and use FnKind instead The principal tool is `FnLikeNode`, which is not often used and can be easily implemented using `rustc_hir::intravisit::FnKind`.
2229 migrations small cleanup This removes needless `format!`'ing of empty string and replaces `vec!` with const strings with const array.
Make `From` impls of NonZero integer const. I also changed the feature gate added to `From` impls of Atomic integer to `const_num_from_num` from `const_convert`. Tracking issue: rust-lang#87852
…ntry-reexported-macro, r=notriddle Add test for duplicated sidebar entries for reexported macro Fixes rust-lang#90015. r? ````@notriddle````
…l-missing-doc-code-examples, r=jyn514 Add test to ensure that the missing_doc_code_examples is not triggered on foreign trait implementations Fixes rust-lang#76450. r? ````@jyn514````
…olnay Fix MIRI UB in `Vec::swap_remove` Fixes rust-lang#90055 I find it weird that `Vec::swap_remove` read the last element to the stack just to immediately put it back in the `Vec` in place of the one at index `index`. It seems much more natural to me to just read the element at position `index` and then move the last element in its place. I guess this might also slightly improve codegen.
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@bors r+ p=14 rollup=never |
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📌 Commit 3680ecd has been approved by |
bors
added
the
S-waiting-on-bors
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☀️ Test successful - checks-actions |
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Finished benchmarking commit (e015ef5): comparison url. Summary: This benchmark run did not return any relevant changes. If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf. @rustbot label: -perf-regression |
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Successful merges:
AbstractConstprivate fields #88644 (AbstractConstprivate fields)VecDeque::with_capacity_in(). #90010 (Avoid overflow inVecDeque::with_capacity_in().)Fromimpls of NonZero integer const. #90077 (MakeFromimpls of NonZero integer const.)Vec::swap_remove#90099 (Fix MIRI UB inVec::swap_remove)Failed merges:
r? @ghost
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