commit 59109b47e10d78f8c9d9aa0a1aacc24fab0e317a
author Peter Kasting <pkasting@chromium.org> Fri Nov 22 01:50:26 2024
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Fri Nov 22 01:50:26 2024
tree 620879cc60463edda30a5e1aef5832bb9528050d
parent 733d738908e629c90037aac9e1aa09ee6d095d5b

Simplify span::copy*().

* Split uintptr_t conversions to a helper to reduce repeated
  justification.
* Avoid special-casing for memmove(), as libc++ already does this
  internally.
* Perfect-forward range inputs; with tsepez' recent changes to add span
  move construction/assignment ops, this could matter.
* Use ranges::copy to avoid pointer math. This was originally not done
  due to inlining issues at `-Oz` making Android slower. However, as of
  February 2024 we no longer use `-Oz` (see
  https://crbug.com/40249335#comment41), so this is no longer relevant.
* Avoid marking the non_overlapping variants as UNSAFE_BUFFER_USAGE.
  These don't do any pointer math or OOB accesses even when the spans
  overlap; the limit of the badness is that span content may be trashed
  in surprising ways. While that's still a safety concern, it's not an
  UNSAFE_BUFFERS concern.
* Less repetitive comments.
* Trivial changes to arg names, requirements, etc.

Bug: 364987728
Change-Id: I589fb4af133c0345b6f19475a8ca8ad9d5259c53
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6040355
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1386586}