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Guarantee that Layout::align returns a non-zero power of two #115653

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merged 2 commits into from
Oct 14, 2023
Merged

Guarantee that Layout::align returns a non-zero power of two #115653

merged 2 commits into from
Oct 14, 2023

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@joshlf joshlf commented Sep 7, 2023

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@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Sep 7, 2023
@dtolnay dtolnay added T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. and removed T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Sep 28, 2023
@dtolnay dtolnay assigned dtolnay and unassigned m-ou-se Sep 28, 2023
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@joshlf joshlf requested a review from dtolnay October 12, 2023 23:04
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Thank you!

This PR commits us to never relaxing the requirement on Layout::from_size_align{,_unchecked} that align must be a power of two.

Based on my reading, we have almost certainly already committed to this guarantee
by documenting "All layouts have an associated non-negative size and a power-of-two alignment". In the absence of a qualification on that such as "this only describes the current implementation and is subject to change in a future version of the standard library", I have a hard time seeing how we could start using Layout for non-power-of-two alignments.

I'll mention @rust-lang/libs-api though: please let me know if anyone feels this is a new guarantee that would need a libs-api FCP.

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dtolnay commented Oct 13, 2023

@bors r+ rollup

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bors commented Oct 13, 2023

📌 Commit a9b0966 has been approved by dtolnay

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 13, 2023
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Oct 13, 2023
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Rollup merge of rust-lang#115653 - joshlf:patch-9, r=dtolnay
0da6895 
Guarantee that Layout::align returns a non-zero power of two
@matthiaskrgr matthiaskrgr mentioned this pull request Oct 13, 2023
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matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Oct 14, 2023
@matthiaskrgr
Rollup merge of rust-lang#115653 - joshlf:patch-9, r=dtolnay
838b948 
Guarantee that Layout::align returns a non-zero power of two
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bors added a commit to rust-lang-ci/rust that referenced this pull request Oct 14, 2023
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Auto merge of rust-lang#116728 - matthiaskrgr:rollup-4xzcsnv, r=matth…
495c5dd 
…iaskrgr

Rollup of 5 pull requests

Successful merges:

 - rust-lang#115653 (Guarantee that Layout::align returns a non-zero power of two)
 - rust-lang#116577 (add `SAFETY` block on the usage of unsafe `getuid`)
 - rust-lang#116618 (Add the V (vector) extension to the riscv64-linux-android target spec)
 - rust-lang#116679 (Remove some unnecessary `unwrap`s)
 - rust-lang#116689 (explicitly handle auto trait leakage in coherence)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 3899957 into rust-lang:master Oct 14, 2023
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@rustbot rustbot added this to the 1.75.0 milestone Oct 14, 2023
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request Oct 14, 2023
@rust-timer
Unrolled build for rust-lang#115653
4fb4561 
Rollup merge of rust-lang#115653 - joshlf:patch-9, r=dtolnay

Guarantee that Layout::align returns a non-zero power of two
@Veykril Veykril mentioned this pull request Oct 17, 2023
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bors-ferrocene bot added a commit to ferrocene/ferrocene that referenced this pull request Oct 17, 2023
@bors-ferrocene @a1phyr
@ColinFinck @ijackson @joshlf @fmease @tgross35 @EvanMerlock @joboet @RalfJung @DaniPopes @Mark-Simulacrum @onur-ozkan @nnethercote @the8472 @sthibaul @reez12g @Kobzol
Merge #54
4d5dcf2 
54: Pull upstream master 2023 10 17 r=pietroalbini a=Veykril

* rust-lang/rust#116196
* rust-lang/rust#116824
* rust-lang/rust#116822
* rust-lang/rust#116477
* rust-lang/rust#116826
* rust-lang/rust#116820
  * rust-lang/rust#116811
  * rust-lang/rust#116808
  * rust-lang/rust#116805
  * rust-lang/rust#116800
  * rust-lang/rust#116798
  * rust-lang/rust#116754
* rust-lang/rust#114370
* rust-lang/rust#116804
  * rust-lang/rust#116802
  * rust-lang/rust#116790
  * rust-lang/rust#116786
  * rust-lang/rust#116709
  * rust-lang/rust#116430
  * rust-lang/rust#116257
  * rust-lang/rust#114157
* rust-lang/rust#116731
* rust-lang/rust#116550
* rust-lang/rust#114330
* rust-lang/rust#116724
* rust-lang/rust#116782
  * rust-lang/rust#116776
  * rust-lang/rust#115955
  * rust-lang/rust#115196
* rust-lang/rust#116775
* rust-lang/rust#114589
* rust-lang/rust#113747
* rust-lang/rust#116772
  * rust-lang/rust#116771
  * rust-lang/rust#116760
  * rust-lang/rust#116755
  * rust-lang/rust#116732
  * rust-lang/rust#116522
  * rust-lang/rust#116341
  * rust-lang/rust#116172
* rust-lang/rust#110604
* rust-lang/rust#110729
* rust-lang/rust#116527
* rust-lang/rust#116688
* rust-lang/rust#116757
  * rust-lang/rust#116753
  * rust-lang/rust#116748
  * rust-lang/rust#116741
  * rust-lang/rust#116594
* rust-lang/rust#116691
* rust-lang/rust#116643
* rust-lang/rust#116683
* rust-lang/rust#116635
* rust-lang/rust#115515
* rust-lang/rust#116742
  * rust-lang/rust#116661
  * rust-lang/rust#116576
  * rust-lang/rust#116540
* rust-lang/rust#116352
* rust-lang/rust#116737
  * rust-lang/rust#116730
  * rust-lang/rust#116723
  * rust-lang/rust#116715
  * rust-lang/rust#116603
  * rust-lang/rust#116591
  * rust-lang/rust#115439
* rust-lang/rust#116264
* rust-lang/rust#116727
  * rust-lang/rust#116704
  * rust-lang/rust#116696
  * rust-lang/rust#116695
  * rust-lang/rust#116644
  * rust-lang/rust#116630
* rust-lang/rust#116728
  * rust-lang/rust#116689
  * rust-lang/rust#116679
  * rust-lang/rust#116618
  * rust-lang/rust#116577
  * rust-lang/rust#115653
* rust-lang/rust#116702
* rust-lang/rust#116015
* rust-lang/rust#115822
* rust-lang/rust#116407
* rust-lang/rust#115719
* rust-lang/rust#115524
* rust-lang/rust#116705
* rust-lang/rust#116645
* rust-lang/rust#116233
* rust-lang/rust#115108
* rust-lang/rust#116670
* rust-lang/rust#116676
* rust-lang/rust#116666



Co-authored-by: Benoît du Garreau <[email protected]>
Co-authored-by: Colin Finck <[email protected]>
Co-authored-by: Ian Jackson <[email protected]>
Co-authored-by: Joshua Liebow-Feeser <[email protected]>
Co-authored-by: León Orell Valerian Liehr <[email protected]>
Co-authored-by: Trevor Gross <[email protected]>
Co-authored-by: Evan Merlock <[email protected]>
Co-authored-by: joboet <[email protected]>
Co-authored-by: Ralf Jung <[email protected]>
Co-authored-by: DaniPopes <[email protected]>
Co-authored-by: Mark Rousskov <[email protected]>
Co-authored-by: onur-ozkan <[email protected]>
Co-authored-by: Nicholas Nethercote <[email protected]>
Co-authored-by: The 8472 <[email protected]>
Co-authored-by: Samuel Thibault <[email protected]>
Co-authored-by: reez12g <[email protected]>
Co-authored-by: Jakub Beránek <[email protected]>
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