The following `HashMap` creation functions don't allocate heap storage for elements.
```
HashMap::new()
HashMap::default()
HashMap::with_hasher()
```
This is good, because it's surprisingly common to create a HashMap and never
use it. So that case should be cheap.
However, `HashSet` does not have the same behaviour. The corresponding creation
functions *do* allocate heap storage for the default number of non-zero
elements (which is 32 slots for 29 elements).
```
HashMap::new()
HashMap::default()
HashMap::with_hasher()
```
This commit gives `HashSet` the same behaviour as `HashMap`, by simply calling
the corresponding `HashMap` functions (something `HashSet` already does for
`with_capacity` and `with_capacity_and_hasher`). It also reformats one existing
`HashSet` construction to use a consistent single-line format.
This speeds up rustc itself by 1.01--1.04x on most of the non-tiny
rustc-benchmarks.
refactor to remove trans::adt and make rustc::ty::layout authoritative
I asked on IRC about optimizing struct layout by reordering fields from most-aligned to least-aligned and somehow ended up getting talked into doing this. The goal here is to make `layout` authoritative and to remove `adt`. The former has been accomplished by reimplementing `represent_type_uncached` and the latter is in progress. @eddyb thought I should make the PR now.
My plan is to reserve the actual optimization for a second PR, as this work is useful by itself.
rustbuild: Nicer error for host builds of targets
If a triple is configured only as a target, not a host, then trying to build
that triple with host artifacts would cause a panic. Fail a little nicer
instead.
Closes#36268
The src/libstd/sys/unix/net.rs file depends on it. It is missing
from Haiku. This workaround should actually 'fix' the problem,
but it turns out the fds-are-cloexec.rs test hangs. I do not
know how related these two issues are, but it warrants further
investigation.
The test is ignored on this platform for now.
* Hand rebased from Niels original work on 1.9.0
Skip binary tidy check when on Windows Linux Subsystem
While it's possible that other linux systems will include "Microsoft" in
their /proc/version, this is deemed unlikely, and since this is a tidy
check, will likely be caught by buildbot/travis either way.
Fixes#36706.
While it's possible that other linux systems will include "Microsoft" in
their /proc/version, this is deemed unlikely, and since this is a tidy
check, will likely be caught by buildbot/travis either way.
s390x's C ABI ty_align and ty_size are not moved because the
implementation of ty_align varies in an atypical pattern: it calls
ty_size for the llvm::Vector type kind. ty_size then cannot be moved
since it indirectly calls ty_align through align.
[breaking-change] Remove TypedArena::with_capacity
This is a follow-up to #36592.
The function is unused by rustc. Also, it doesn't really follow the
usual meaning of a `with_capacity` function because the first chunk
allocation is now delayed until the first `alloc` call.
This change reduces the size of `TypedArena` by one `usize`.
@eddyb: we discussed this on IRC. Would you like to review it?
Tim Neumann
bors
Jeffrey Seyfried
Srinivas Reddy Thatiparthy
Nicholas Nethercote
Gianni Ciccarelli
Austin Hicks
Corey Farwell
Alexander von Gluck IV
Jake Goulding
Niels Sascha Reedijk
Mark-Simulacrum
Patrick Walton