Remove common usage pattern from AllocRef
#69026
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
rust-highfive
added
the
S-waiting-on-review
|
The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
TimDiekmann
force-pushed
the
common-usage
branch
from
80ece94
to
25de80a
Compare
|
cc @rust-lang/libs @bors r+ |
|
📌 Commit 25de80a has been approved by |
bors
added
S-waiting-on-bors
JohnTitor
added a commit
to JohnTitor/rust
that referenced
this pull request
Feb 12, 2020
Remove common usage pattern from `AllocRef` This removes the common usage patterns from `AllocRef`: - `alloc_one` - `dealloc_one` - `alloc_array` - `realloc_array` - `dealloc_array` Actually, they add nothing to `AllocRef` except a [convenience wrapper around `Layout` and other methods in this trait](https://doc.rust-lang.org/1.41.0/src/core/alloc.rs.html#1076-1240) but have a major flaw: The documentation of `AllocRefs` notes, that > some higher-level allocation methods (`alloc_one`, `alloc_array`) are well-defined on zero-sized types and can optionally support them: it is left up to the implementor whether to return `Err`, or to return `Ok` with some pointer. With the current API, `GlobalAlloc` does not have those methods, so they cannot be overridden for `liballoc::Global`, which means that even if the global allocator would support zero-sized allocations, `alloc_one`, `alloc_array`, and `realloc_array` for `liballoc::Global` will error, while calling `alloc` with a zeroed-size `Layout` could succeed. Even worse: allocating with `alloc` and deallocating with `dealloc_{one,array}` could end up with not calling `dealloc` at all! For the full discussion please see rust-lang/wg-allocators#18 r? @Amanieu
bors
added a commit
that referenced
this pull request
Feb 12, 2020
Rollup of 11 pull requests Successful merges: - #67695 (Added dyn and true keyword docs) - #68487 ([experiment] Support linking from a .rlink file) - #68554 (Split lang_items to crates `rustc_hir` and `rustc_passes`.) - #68937 (Test failure of unchecked arithmetic intrinsics in const eval) - #68947 (Python script PEP8 style guide space formatting and minor Python source cleanup) - #68999 (remove dependency on itertools) - #69026 (Remove common usage pattern from `AllocRef`) - #69027 (Add missing `_zeroed` varants to `AllocRef`) - #69058 (Preparation for allocator aware `Box`) - #69070 (Add self to .mailmap) - #69077 (Fix outdated doc comment.) Failed merges: r? @ghost
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This removes the common usage patterns from
AllocRef:alloc_onedealloc_onealloc_arrayrealloc_arraydealloc_arrayActually, they add nothing to
AllocRefexcept a convenience wrapper aroundLayoutand other methods in this trait but have a major flaw: The documentation ofAllocRefsnotes, thatWith the current API,
GlobalAllocdoes not have those methods, so they cannot be overridden forliballoc::Global, which means that even if the global allocator would support zero-sized allocations,alloc_one,alloc_array, andrealloc_arrayforliballoc::Globalwill error, while callingallocwith a zeroed-sizeLayoutcould succeed. Even worse: allocating withallocand deallocating withdealloc_{one,array}could end up with not callingdeallocat all!For the full discussion please see rust-lang/wg-allocators#18
r? @Amanieu