The acronym is not descriptive unless one has seen it before.
* Rename the `oom` function to `handle_alloc_error`. It was **stabilized in 1.28**, so if we do this at all we need to land it this cycle.
* Rename `set_oom_hook` to `set_alloc_error_hook`
* Rename `take_oom_hook` to `take_alloc_error_hook`
Bikeshed: `alloc` v.s. `allocator`, `error` v.s. `failure`
As discussed in
https://github.com/rust-lang/rust/issues/49668#issuecomment-384893456
and subsequent, there are use-cases where the OOM handler needs to know
the size of the allocation that failed. The alignment might also be a
cause for allocation failure, so providing it as well can be useful.
When the RawVec::try_reserve* methods were added, they took the place of
the ::reserve* methods in the source file, and new ::reserve* methods
wrapping the new try_reserve* methods were created. But the
documentation didn't move along, such that:
- reserve_* methods are barely documented.
- try_reserve_* methods have unmodified documentation from reserve_*,
such that their documentation indicate they are panicking/aborting.
This moves the documentation back to the right methods, with a
placeholder documentation for the try_reserve* methods.
std: Minimize size of panicking on wasm
This commit applies a few code size optimizations for the wasm target to
the standard library, namely around panics. We notably know that in most
configurations it's impossible for us to print anything in
wasm32-unknown-unknown so we can skip larger portions of panicking that
are otherwise simply informative. This allows us to get quite a nice
size reduction.
Finally we can also tweak where the allocation happens for the
`Box<Any>` that we panic with. By only allocating once unwinding starts
we can reduce the size of a panicking wasm module from 44k to 350 bytes.
Some modules were still using the deprecated `allocator` module, use the
`alloc` module instead.
Some modules were using `super` while it's not needed.
Some modules were more or less ordering them, and other not, so the
latter have been modified to match the others.
Create one canonical location which panics with "capacity overflow" instead of
having many. This reduces the size of a `panic!("{}", 1)` binary on wasm from
34k to 17k.
94d1970bba moved the alloc::allocator
module to core::heap, moving e.g. Alloc and Layout out of the alloc
crate. While alloc::heap reexports them, it's better to use them from
where they really come from.
The `RawVec` type has a number of invariants that it upholds throughout its
execution, and as a result many of the runtime checks imposed by using `Layout`
in a "raw" fashion aren't actually necessary. For example a `RawVec`'s capacity
is intended to always match the layout which "fits" the allocation, so we don't
need any runtime checks when retrieving the current `Layout` for a vector.
Consequently, this adds a safe `current_layout` function which internally uses
the `from_size_align_unchecked` function.
Along the same lines we know that most construction of new layouts will not
overflow. All allocations in `RawVec` are kept below `isize::MAX` and valid
alignments are also kept low enough that we're guaranteed that `Layout` for a
doubled vector will never overflow and will always succeed construction.
Consequently a few locations can use `from_size_align_unchecked` in addition
when constructing the *new* layout to allocate (or reallocate), which allows for
eliding some more runtime checks.
Overall this should significant improve performance for an important function,
`RawVec::double`. This commit removes four runtime jumps before `__rust_realloc`
is called, as well as one after it's called.
This PR is an implementation of [RFC 1974] which specifies a new method of
defining a global allocator for a program. This obsoletes the old
`#![allocator]` attribute and also removes support for it.
[RFC 1974]: https://github.com/rust-lang/rfcs/pull/197
The new `#[global_allocator]` attribute solves many issues encountered with the
`#![allocator]` attribute such as composition and restrictions on the crate
graph itself. The compiler now has much more control over the ABI of the
allocator and how it's implemented, allowing much more freedom in terms of how
this feature is implemented.
cc #27389
Replaced by adding extra imports, adding hidden code (`# ...`), modifying
examples to be runnable (sorry Homura), specifying non-Rust code, and
converting to should_panic, no_run, or compile_fail.
Remaining "```ignore"s received an explanation why they are being ignored.
Includes methods exposing underlying allocator and the dellocation
routine.
Includes test illustrating a tiny `Alloc` that just bounds the total
bytes allocated.
Alpha-renamed `Allocator` to `Alloc` (and `HeapAllocator` to `HeapAlloc`).
kennytm