.sift_down can either choose to compare the element on the way down (and
place it during descent), or to sift down an element fully, then sift
back up to place it.
A previous PR changed .sift_down() to the former behavior, which is much
faster for relatively small heaps and for elements that are cheap to
compare.
A benchmarking run suggested that BinaryHeap::pop() suffers
improportionally from this, and that it should use the second strategy
instead. It's logical since .pop() brings last element from the
heapified vector into index 0, it's very likely that this element will
end up at the bottom again.
This commit changes our distribution and in-tree sources to pass the `-C rpath`
flag by default during compiles. This means that from-source builds, including
our release channels, will have this option enabled as well. Motivated
by #29941, this change means that the compiler should be usable as-is on all
platforms just after extraction or installation. This experience is already true
on Windows but on Unixes you still need to set up LD_LIBRARY_PATH or the
equivalent, which can often be unfortunate.
This option was originally turned off by default for Linux distributions who
tend to take care of these sorts of details themselves, so it is expected that
all those builds of Rust will want to pass `--disable-rpath` to the configure
script to preserve that behavior.
Closes#29941
Currently a compiler can be built with the `--disable-elf-tls` option for compatibility with OSX 10.6 which doesn't have ELF TLS. This is unfortunate, however, as a whole new compiler must be generated which can take some time. These commits add a new (feature gated) `cfg(target_thread_local)` annotation set by the compiler which indicates whether `#[thread_local]` is available for use. The compiler now interprets `MACOSX_DEPLOYMENT_TARGET` (a standard environment variable) to set this flag on OSX. With this we may want to start compiling our OSX nightlies with `MACOSX_DEPLOYMENT_TARGET` set to 10.6 which would allow the compiler out-of-the-box to generate 10.6-compatible binaries.
For now the compiler still by default targets OSX 10.7 by allowing ELF TLS by default (e.g. if `MACOSX_DEPLOYMENT_TARGET` isn't set).
On some weird setup where $SHELL is a relative path (can happen under GNU
Screen,) `file -L "$BIN_TO_PROBE"` fails and $CFG_CPUTYPE is wrongly set to
i686. We should not only check its string value but also permission on
filesystem.
This transitions the standard library's `thread_local!` macro to use the
freshly-added and gated `#[cfg(target_thread_local)]` attribute. This greatly
simplifies the `#[cfg]` logic in play here, but requires that the standard
library expose both the OS and ELF TLS implementation modules as unstable
implementation details.
The implementation details were shuffled around a bit but end up generally
compiling to the same thing.
Closes#26581 (this supersedes the need for the option)
Closes#27057 (this also starts ignoring the option)
This change modifies the feature gating of special `#[cfg]` attributes to not
require a `#![feature]` directive in the crate-of-use if the source of the macro
was declared with `#[allow_internal_unstable]`. This enables the standard
library's macro for `thread_local!` to make use of the
`#[cfg(target_thread_local)]` attribute despite it being feature gated (e.g.
it's a hidden implementation detail).
Currently the standard library has some pretty complicated logic to detect
whether #[thread_local] should be used or whether it's supported. This is also
unfortunately not quite true for OSX where not all versions support
the #[thread_local] attribute (only 10.7+ does). Compiling code for OSX 10.6 is
typically requested via the MACOSX_DEPLOYMENT_TARGET environment variable (e.g.
the linker recognizes this), but the standard library unfortunately does not
respect this.
This commit updates the compiler to add a `target_thread_local` cfg annotation
if the platform being targeted supports the `#[thread_local]` attribute. This is
feature gated for now, and it is only true on non-aarch64 Linux and 10.7+ OSX
(e.g. what the module already does today). Logic has also been added to parse
the deployment target environment variable.
It's been awhile since we last updated jemalloc, and there's likely some bugs
that have been fixed since the last version we're using, so let's try to update
again.
Types like `&AssertRecoverSafe<T>` and `Rc<AssertRecoverSafe<T>>` were
mistakenly not considered recover safe, but the point of the assertion wrapper
is that it indeed is! This was caused by an interaction between the
`RecoverSafe` and `NoUnsafeCell` marker traits, and this is updated by adding an
impl of the `NoUnsafeCell` marker trait for `AssertRecoverSafe` to ensure that
it never interacts with the other negative impls of `RecoverSafe`.
cc #30510
It's been awhile since we last updated jemalloc, and there's likely some bugs
that have been fixed since the last version we're using, so let's try to update
again.
Add note when item accessed from module via `m.i` rather than `m::i`.
(I tried to make this somewhat future-proofed, in that the `UnresolvedNameContext` could be expanded in the future with other cases besides paths that are known to be modules.)
This supersedes PR #30356 ; since I'm responsible for a bunch of new code here, someone else should review it. :)
this PR reverts previous ones, that tried to make `cc` to found `estdc++` in `/usr/local/lib`. It causes more trouble than it resolvs things: rustc become unbuildable if another version already exists in `/usr/local` (for example, `libstd-xxxx.so` is found in `/usr/local/lib` and in builddir).
so this PR tries another way to achieve build, but using the good linker for building. By default, rustc use `cc` for linking. But under OpenBSD, `cc` is gcc 4.2.1 from base, whereas we build with gcc 4.9 from ports. By linking using the compiler found at compile-time, we ensure that the compiler will found his own stdc++ library without trouble.
r? @alexcrichton
correcting use of ':' in sentences.
The colon `:` should be used only when the sentence preceeding it is a
complete sentence. If this is not the case, then a `;` should be used;
this denotes that the following fragment is a part of the previous
fragment.
By default, rustc use `cc` as linker. Under OpenBSD, `cc` is gcc version 4.2.1.
So use the compiler found at configure-time for linking: it will be gcc 4.9.
It permits to resolv problem of finding -lestdc++ or -lgcc. For base gcc (4.2), there are in not standard path, whereas for ports gcc (4.9) there are in standard path.
Rust already supports Linux's getrandom(2), which is very similar and
was based on getentropy(2). This is a pretty clean, simple addition that
uses the same approach as the iOS randomness API support.
