Add sanitizer support on FreeBSD
Restarting #47337. Everything is better now, no more weird llvm problems, well not everything:
Unfortunately, the sanitizers don't have proper support for versioned symbols (https://github.com/google/sanitizers/issues/628), so `libc`'s usage of `stat@FBSD_1.0` and so on explodes, e.g. in calling `std::fs::metadata`.
Building std (now easy thanks to cargo `-Zbuild-std`) and libc with `freebsd12/13` config via the `LIBC_CI=1` env variable is a good workaround…
```
LIBC_CI=1 RUSTFLAGS="-Z sanitizer=address" cargo +san-test -Zbuild-std run --target x86_64-unknown-freebsd --verbose
```
…*except* std won't build because there's no `st_lspare` in the ino64 version of the struct, so an std patch is required:
```diff
--- i/src/libstd/os/freebsd/fs.rs
+++ w/src/libstd/os/freebsd/fs.rs
@@ -66,8 +66,6 @@ pub trait MetadataExt {
fn st_flags(&self) -> u32;
#[stable(feature = "metadata_ext2", since = "1.8.0")]
fn st_gen(&self) -> u32;
- #[stable(feature = "metadata_ext2", since = "1.8.0")]
- fn st_lspare(&self) -> u32;
}
#[stable(feature = "metadata_ext", since = "1.1.0")]
@@ -136,7 +134,4 @@ impl MetadataExt for Metadata {
fn st_flags(&self) -> u32 {
self.as_inner().as_inner().st_flags as u32
}
- fn st_lspare(&self) -> u32 {
- self.as_inner().as_inner().st_lspare as u32
- }
}
```
I guess std could like.. detect that `libc` isn't built for the old ABI, and replace the implementation of `st_lspare` with a panic?
Revert the fundamental changes in #74762 and #75257
Before possibly going over to #75487. Also contains some added and fixed comments.
r? @Mark-Simulacrum
std/sys/unix/time: make it easier for LLVM to optimize `Instant` subtraction.
This PR is the minimal change necessary to get LLVM to optimize `if self.t.tv_nsec >= other.t.tv_nsec` to branchless instructions (at least on x86_64), inspired by @m-ou-se's own attempts at optimizing `Instant` subtraction.
I stumbled over this by looking at the total number of instructions executed by `rustc -Z self-profile`, and found that after disabling ASLR, the largest source of non-determinism remaining was from this `if` taking one branch or the other, depending on the values involved.
The reason this code is even called so many times to make a difference, is that `measureme` (the `-Z self-profile` implementation) currently uses `Instant::elapsed` for its event timestamps (of which there can be millions).
I doubt it's critical to land this, although perhaps it could slightly improve some forms of benchmarking.
Migrate unit tests of btree collections to their native breeding ground
There's one BTreeSet test case that I couldn't easily convince to come along, maybe because it truly is an integration test. But leaving it in place would mean git wouldn't see the move so I also moved it to a new file.
r? @Mark-Simulacrum
BTreeMap: purge innocent use of into_kv_mut
Replace the use of `into_kv_mut` into more precise calls. This makes more sense if you know that the single remaining use of `into_kv_mut` is in fact evil and can be trialled in court (#75200) and sent to a correction facility (#73971).
No real performance difference reported (but functions that might benefit a tiny constant bit like `BTreeMap::get_mut` aren't benchmarked):
```
benchcmp old new --threshold 5
name old ns/iter new ns/iter diff ns/iter diff % speedup
btree::map::clone_fat_100 63,073 59,256 -3,817 -6.05% x 1.06
btree::map::iter_100 3,514 3,235 -279 -7.94% x 1.09
```
Change Debug impl of SocketAddr and IpAddr to match their Display output
This has already been done for `SocketAddrV4`, `SocketAddrV6`, `IpAddrV4` and `IpAddrV6`. I don't see a point to keep the rather bad to read derived impl, especially so when pretty printing:
V4(
127.0.0.1
)
From the `Display`, one can easily and unambiguously see if it's V4 or V6. Two examples:
```
127.0.0.1:443
[2001:db8:85a3::8a2e:370:7334]:443
```
Luckily the docs explicitly state that `Debug` output is not stable and that it may be changed at any time.
Using `Display` as `Debug` is very convenient for configuration structs (e.g. for webservers) that often just have a `derive(Debug)` and are printed that way to the one starting the server.
Improve documentation on process::Child.std* fields
As a relative beginner, it took a while for me to figure out I could just steal the references to avoid partially moving the child and thus retain ability to call functions on it (and store it in structs etc).
Constified str::from_utf8_unchecked
This would be useful for const code to use an array to construct a string using guaranteed utf8 inputs, and then create a `&str` from it.
As a relative beginner, it took a while for me to figure out I could just steal the references to avoid partially moving the child and thus retain ability to call functions on it (and store it in structs etc).
Stop BTreeMap casts from reborrowing
Down in btree/node.rs, the interface and use of `cast_unchecked` look a bit shady. It's really just there for inverting `forget_type` which does not borrow. By borrowing we can't write the same `cast_unchecked` in the same way at the Handle level.
No change in undefined behaviour or performance.
Expand function pointer docs
Be more explicit in the ABI section, and add a section on how to obtain a function pointer, which can be somewhat confusing.
Cc https://github.com/rust-lang/rust/issues/75239
Hard way to respect BTreeMap's minimum node length
Resolves#74834 the hard way (though not the hardest imaginable).
Benchmarks (which are all biased/realistic, inserting keys in ascending order) say:
```
benchcmp r0 r1 --threshold 10
name r0 ns/iter r1 ns/iter diff ns/iter diff % speedup
btree::map::clone_slim_100_and_clear 2,183 2,723 540 24.74% x 0.80
btree::map::clone_slim_100_and_drain_all 3,652 4,173 521 14.27% x 0.88
btree::map::clone_slim_100_and_drain_half 3,320 3,940 620 18.67% x 0.84
btree::map::clone_slim_100_and_into_iter 2,154 2,717 563 26.14% x 0.79
btree::map::clone_slim_100_and_pop_all 3,372 3,870 498 14.77% x 0.87
btree::map::clone_slim_100_and_remove_all 5,111 5,647 536 10.49% x 0.91
btree::map::clone_slim_100_and_remove_half 3,259 3,821 562 17.24% x 0.85
btree::map::iter_0 1,733 1,509 -224 -12.93% x 1.15
btree::map::iter_100 2,714 3,739 1,025 37.77% x 0.73
btree::map::iter_10k 3,728 4,269 541 14.51% x 0.87
btree::map::range_unbounded_unbounded 28,426 36,631 8,205 28.86% x 0.78
btree::map::range_unbounded_vs_iter 28,808 34,056 5,248 18.22% x 0.85
```
This difference is not caused by the `debug_assert`-related code in the function `splitpoint`, it's the same without.
Add `array` lang item and `[T; N]::map(f: FnMut(T) -> S)`
This introduces an `array` lang item so functions can be defined on top of `[T; N]`. This was previously not done because const-generics was not complete enough to allow for this. Now it is in a state that is usable enough to start adding functions.
The function added is a monadic (I think?) map from `[T; N] -> [S; N]`. Until transmute can function on arrays, it also allocates an extra temporary array, but this can be removed at some point.
r? @lcnr
