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document that the null pointer has the 0 address #116988

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merged 1 commit into from
Nov 6, 2023
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RalfJung
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Fixes #116895

Will need t-lang FCP, but I think this is fairly uncontroversial -- there's probably already tons of code out there that relies on this.

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rustbot commented Oct 20, 2023

r? @thomcc

(rustbot has picked a reviewer for you, use r? to override)

@RalfJung RalfJung added T-lang Relevant to the language team, which will review and decide on the PR/issue. I-lang-nominated Nominated for discussion during a lang team meeting. labels Oct 20, 2023
@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 Oct 20, 2023
@RalfJung RalfJung removed the T-libs Relevant to the library team, which will review and decide on the PR/issue. label Oct 20, 2023
@scottmcm
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Notably these functions only work on T: Thin, so I think this is also an unavoidable consequence of other things that we've previously guaranteed around Option<NonNull<T>>.

@rfcbot fcp merge

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rfcbot commented Oct 21, 2023

Team member @scottmcm has proposed to merge this. The next step is review by the rest of the tagged team members:

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

cc @rust-lang/lang-advisors: FCP proposed for lang, please feel free to register concerns.
See this document for info about what commands tagged team members can give me.

@rfcbot rfcbot added proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. labels Oct 21, 2023
@scottmcm scottmcm removed the I-lang-nominated Nominated for discussion during a lang team meeting. label Oct 21, 2023
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@rustbot labels +I-lang-nominated

I'm going to nominate even though FCP has been proposed so that this comes up at least once in the meeting.

@rustbot rustbot added the I-lang-nominated Nominated for discussion during a lang team meeting. label Oct 24, 2023
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@rfcbot reviewed

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tmandry commented Oct 24, 2023

@traviscross Doesn't our agenda generator include proposed FCPs already?

We already have quite a long list of nominated issues; I don't think nominating every newly proposed FCP is helping with that.

(edit: I am specifically pushing back on nominating for the purpose of getting eyes and checkboxes on the FCP. If your goal is to spark a discussion within the lang team meeting, then nominating is good for that.)

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tmandry commented Oct 24, 2023

From #116895 (comment) it sounds like you've already considered the implications for provenance. With those aside I think we should go ahead and commit to this.

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@rfcbot rfcbot added the final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. label Oct 24, 2023
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rfcbot commented Oct 24, 2023

🔔 This is now entering its final comment period, as per the review above. 🔔

@rfcbot rfcbot removed the proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. label Oct 24, 2023
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Yeah, the good thing is that nobody expects to be able to load from a null ptr so provenance basically does not matter.

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Yes, all p-FCPs are included in the meeting in the section that starts with

Proposed FCPs

Check your boxes!

So I interpreted the nomination here as "please p-fcp merge this", which is why I removed nomination after doing that.

Checking boxes is generally something that should be done asynchronously via the https://rfcbot.rs/ list, so that the synchronous time in triage can be spent on things with specific questions in the nomination.

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This is not a blocker for this issue, but could we please get a comment somewhere appropriate that says what code should do in the rare case where it has memory mapped at 0 and needs to write to it? (e.g. low-level hardware programming, or weird userspace programming situations that need the zero page mapped.) We should identify what function will allow such a write without complaint, and point people to that.

@scottmcm scottmcm removed the I-lang-nominated Nominated for discussion during a lang team meeting. label Oct 25, 2023
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RalfJung commented Oct 25, 2023 via email

@rfcbot rfcbot added finished-final-comment-period The final comment period is finished for this PR / Issue. to-announce Announce this issue on triage meeting and removed final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. labels Nov 3, 2023
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rfcbot commented Nov 3, 2023

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

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RalfJung commented Nov 4, 2023

@thomcc this should be ready to land then :)

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Since this is only a documentation change and the semantic was approved by T-lang, I'll go ahead and merge this. Feel free to r- if you think that a T-libs review is required.

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@bors r+ rollup

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bors commented Nov 6, 2023

📌 Commit 98d54da has been approved by WaffleLapkin

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 Nov 6, 2023
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bors commented Nov 6, 2023

⌛ Testing commit 98d54da with merge b049093...

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bors commented Nov 6, 2023

☀️ Test successful - checks-actions
Approved by: WaffleLapkin
Pushing b049093 to master...

@bors bors added the merged-by-bors This PR was explicitly merged by bors. label Nov 6, 2023
@bors bors merged commit b049093 into rust-lang:master Nov 6, 2023
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@rustbot rustbot added this to the 1.75.0 milestone Nov 6, 2023
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Finished benchmarking commit (b049093): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

mean range count
Regressions ❌
(primary)
0.9% [0.4%, 2.0%] 6
Regressions ❌
(secondary)
4.2% [4.2%, 4.2%] 1
Improvements ✅
(primary)
-0.5% [-0.5%, -0.5%] 2
Improvements ✅
(secondary)
- - 0
All ❌✅ (primary) 0.6% [-0.5%, 2.0%] 8

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

mean range count
Regressions ❌
(primary)
0.6% [0.6%, 0.6%] 2
Regressions ❌
(secondary)
0.8% [0.8%, 0.8%] 1
Improvements ✅
(primary)
- - 0
Improvements ✅
(secondary)
- - 0
All ❌✅ (primary) 0.6% [0.6%, 0.6%] 2

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 662.908s -> 662.932s (0.00%)
Artifact size: 308.97 MiB -> 308.95 MiB (-0.01%)

@RalfJung RalfJung deleted the null branch November 7, 2023 06:45
bors-ferrocene bot added a commit to ferrocene/ferrocene that referenced this pull request Nov 7, 2023
89: Automated pull from upstream `master` r=Dajamante a=github-actions[bot]


This PR pulls the following changes from the upstream repository:

* rust-lang/rust#117006
* rust-lang/rust#117511
* rust-lang/rust#117641
  * rust-lang/rust#117637
  * rust-lang/rust#117631
  * rust-lang/rust#117516
  * rust-lang/rust#117190
* rust-lang/rust#117292
* rust-lang/rust#117603
* rust-lang/rust#116988
* rust-lang/rust#117630
  * rust-lang/rust#117615
  * rust-lang/rust#117613
  * rust-lang/rust#117592
* rust-lang/rust#117578
* rust-lang/rust#117435
* rust-lang/rust#117607



90: bump serde and serde_derive r=tshepang a=Dajamante

Trying to get around the failure seen in #86 

Co-authored-by: Ralf Jung <[email protected]>
Co-authored-by: Esteban Küber <[email protected]>
Co-authored-by: SparrowLii <[email protected]>
Co-authored-by: Matthias Krüger <[email protected]>
Co-authored-by: Gurinder Singh <[email protected]>
Co-authored-by: Michael Goulet <[email protected]>
Co-authored-by: Thom Chiovoloni <[email protected]>
Co-authored-by: klensy <[email protected]>
Co-authored-by: Jack Huey <[email protected]>
Co-authored-by: bjorn3 <[email protected]>
Co-authored-by: hkalbasi <[email protected]>
Co-authored-by: bors <[email protected]>
Co-authored-by: Sven Marnach <[email protected]>
Co-authored-by: Rémy Rakic <[email protected]>
Co-authored-by: aissata <[email protected]>
@apiraino apiraino removed the to-announce Announce this issue on triage meeting label Nov 9, 2023
netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request Mar 3, 2024
Pkgsrc changes:
 * Adjust patches and cargo checksums to new versions.
 * For an external LLVM, set dependency of llvm >= 16, in accordance
   with the upstream changes.
 * Mark that on NetBSD we now need >= 9.0, so 8.x is no longer supported.
 * On NetBSD/sparc64 10.x, we now need GCC 12 to build the embedded
   LLVM, which is version 17; apparently GCC 10.4 or 10.5 mis-compiles it,
   resulting in an illegal instruction fault during the build.
   Ref. rust-lang/rust#117231

Upstream changes:

Version 1.75.0 (2023-12-28)
==========================

- [Stabilize `async fn` and return-position `impl Trait` in traits.]
  (rust-lang/rust#115822)
- [Allow function pointer signatures containing `&mut T` in `const` contexts.]
  (rust-lang/rust#116015)
- [Match `usize`/`isize` exhaustively with half-open ranges.]
  (rust-lang/rust#116692)
- [Guarantee that `char` has the same size and alignment as `u32`.]
  (rust-lang/rust#116894)
- [Document that the null pointer has the 0 address.]
  (rust-lang/rust#116988)
- [Allow partially moved values in `match`.]
  (rust-lang/rust#103208)
- [Add notes about non-compliant FP behavior on 32bit x86 targets.]
  (rust-lang/rust#113053)
- [Stabilize ratified RISC-V target features.]
  (rust-lang/rust#116485)

Compiler
--------

- [Rework negative coherence to properly consider impls that only
  partly overlap.] (rust-lang/rust#112875)
- [Bump `COINDUCTIVE_OVERLAP_IN_COHERENCE` to deny, and warn in dependencies.]
  (rust-lang/rust#116493)
- [Consider alias bounds when computing liveness in NLL.]
  (rust-lang/rust#116733)
- [Add the V (vector) extension to the `riscv64-linux-android` target spec.]
  (rust-lang/rust#116618)
- [Automatically enable cross-crate inlining for small functions]
  (rust-lang/rust#116505)
- Add several new tier 3 targets:
    - [`csky-unknown-linux-gnuabiv2hf`]
      (rust-lang/rust#117049)
    - [`i586-unknown-netbsd`]
      (rust-lang/rust#117170)
    - [`mipsel-unknown-netbsd`]
      (rust-lang/rust#117356)

Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.

Libraries
---------

- [Override `Waker::clone_from` to avoid cloning `Waker`s unnecessarily.]
  (rust-lang/rust#96979)
- [Implement `BufRead` for `VecDeque<u8>`.]
  (rust-lang/rust#110604)
- [Implement `FusedIterator` for `DecodeUtf16` when the inner iterator does.]
  (rust-lang/rust#110729)
- [Implement `Not, Bit{And,Or}{,Assign}` for IP addresses.]
  (rust-lang/rust#113747)
- [Implement `Default` for `ExitCode`.]
  (rust-lang/rust#114589)
- [Guarantee representation of None in NPO]
  (rust-lang/rust#115333)
- [Document when atomic loads are guaranteed read-only.]
  (rust-lang/rust#115577)
- [Broaden the consequences of recursive TLS initialization.]
  (rust-lang/rust#116172)
- [Windows: Support sub-millisecond sleep.]
  (rust-lang/rust#116461)
- [Fix generic bound of `str::SplitInclusive`'s `DoubleEndedIterator` impl]
  (rust-lang/rust#100806)
- [Fix exit status / wait status on non-Unix `cfg(unix)` platforms.]
  (rust-lang/rust#115108)

Stabilized APIs
---------------

- [`Atomic*::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicUsize.html#method.from_ptr)
- [`FileTimes`]
  (https://doc.rust-lang.org/stable/std/fs/struct.FileTimes.html)
- [`FileTimesExt`]
  (https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTimesExt.html)
- [`File::set_modified`]
  (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.set_modified)
- [`File::set_times`]
  (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.set_times)
- [`IpAddr::to_canonical`]
  (https://doc.rust-lang.org/stable/core/net/enum.IpAddr.html#method.to_canonical)
- [`Ipv6Addr::to_canonical`]
  (https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.to_canonical)
- [`Option::as_slice`]
  (https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.as_slice)
- [`Option::as_mut_slice`]
  (https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.as_mut_slice)
- [`pointer::byte_add`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_add)
- [`pointer::byte_offset`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_offset)
- [`pointer::byte_offset_from`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_offset_from)
- [`pointer::byte_sub`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_sub)
- [`pointer::wrapping_byte_add`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.wrapping_byte_add)
- [`pointer::wrapping_byte_offset`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.wrapping_byte_offset)
- [`pointer::wrapping_byte_sub`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.wrapping_byte_sub)

These APIs are now stable in const contexts:

- [`Ipv6Addr::to_ipv4_mapped`]
  (https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.to_ipv4_mapped)
- [`MaybeUninit::assume_init_read`]
  (https://doc.rust-lang.org/stable/core/mem/union.MaybeUninit.html#method.assume_init_read)
- [`MaybeUninit::zeroed`]
  (https://doc.rust-lang.org/stable/core/mem/union.MaybeUninit.html#method.zeroed)
- [`mem::discriminant`]
  (https://doc.rust-lang.org/stable/core/mem/fn.discriminant.html)
- [`mem::zeroed`]
  (https://doc.rust-lang.org/stable/core/mem/fn.zeroed.html)

Cargo
-----

- [Add new packages to `[workspace.members]` automatically.]
  (rust-lang/cargo#12779)
- [Allow version-less `Cargo.toml` manifests.]
  (rust-lang/cargo#12786)
- [Make browser links out of HTML file paths.]
  (rust-lang/cargo#12889)

Rustdoc
-------

- [Accept less invalid Rust in rustdoc.]
  (rust-lang/rust#117450)
- [Document lack of object safety on affected traits.]
  (rust-lang/rust#113241)
- [Hide `#[repr(transparent)]` if it isn't part of the public ABI.]
  (rust-lang/rust#115439)
- [Show enum discriminant if it is a C-like variant.]
  (rust-lang/rust#116142)

Compatibility Notes
-------------------

- [FreeBSD targets now require at least version 12.]
  (rust-lang/rust#114521)
- [Formally demote tier 2 MIPS targets to tier 3.]
  (rust-lang/rust#115238)
- [Make misalignment a hard error in `const` contexts.]
  (rust-lang/rust#115524)
- [Fix detecting references to packed unsized fields.]
  (rust-lang/rust#115583)
- [Remove support for compiler plugins.]
  (rust-lang/rust#116412)
celinval added a commit to celinval/rust-dev that referenced this pull request Jun 4, 2024
Update Rust toolchain from nightly-2023-11-06 to nightly-2023-11-07
without any other source changes.
This is an automatically generated pull request. If any of the CI checks
fail, manual intervention is required. In such a case, review the
changes at https://github.com/rust-lang/rust from
rust-lang@fee5518
up to
rust-lang@189d6c7.
The log for this commit range is:
rust-lang@189d6c71f3 Auto merge of
rust-lang#117641 - matthiaskrgr:rollup-f9c12td, r=matthiaskrgr
rust-lang@9efe60b1eb Rollup merge of
rust-lang#117637 - lqd:trivial-bounds-with-binder-vars, r=compiler-errors
rust-lang@2a1f8bccee Rollup merge of
rust-lang#117631 - smarnach:error-request-doc-fix, r=ChrisDenton
rust-lang@8a34fea835 Rollup merge of
rust-lang#117516 - matthiaskrgr:test_effects_113375_oob, r=fee1-dead
rust-lang@1683df7d3b Rollup merge of
rust-lang#117190 - matthiaskrgr:test_effects_113381, r=fee1-dead
rust-lang@fb61292105 Auto merge of
rust-lang#117292 - estebank:issue-80446, r=davidtwco
rust-lang@4b7aacaa4f Silence redundant
error on typo resulting on binop
rust-lang@aea82b268a Auto merge of
rust-lang#117603 - HKalbasi:make-feature-additive, r=Nilstrieb
rust-lang@58351ae03f add test for trivial
bound not holding in `soa-derive`
rust-lang@2beca157c9 check binders with
bound vars for global bounds that don't hold
rust-lang@b049093560 Auto merge of
rust-lang#116988 - RalfJung:null, r=WaffleLapkin
rust-lang@e1fcecb1b9 Auto merge of
rust-lang#117630 - matthiaskrgr:rollup-v0d5p3f, r=matthiaskrgr
rust-lang@3a096e96fa Documentation
cleanup for core::error::Request.
rust-lang@b88d62e222 Rollup merge of
rust-lang#117615 - bjorn3:misc_changes, r=davidtwco
rust-lang@ec35c03143 Rollup merge of
rust-lang#117613 - jackh726:vacation, r=compiler-errors
rust-lang@60dca87cff Rollup merge of
rust-lang#117592 - thomcc:env-span-wrong, r=davidtwco
rust-lang@6bf2fb3679 Auto merge of
rust-lang#117578 - compiler-errors:derive-encode-in-rustc_type_ir, r=davidtwco
rust-lang@f9b644636f Auto merge of
rust-lang#117435 - SparrowLii:nightly_parallel, r=oli-obk,davidtwco
rust-lang@fcca978aa0 Auto merge of
rust-lang#117607 - klensy:clang-17.0.4, r=Mark-Simulacrum
rust-lang@152a4e90d1 Auto merge of
rust-lang#117585 - dnbln:feat/move-kw-span, r=cjgillot
rust-lang@f2a40e99ff use portable
AtomicU64 for powerPC and MIPS
rust-lang@7a892ab8d8 Auto merge of
rust-lang#117576 - the8472:fix-io-copy-vec, r=Mark-Simulacrum
rust-lang@c8a25eddfe Make the randomize
feature of rustc_abi additive
rust-lang@ec29a02071 Update doc comment
for CodegenBackend::link
rust-lang@ba82056a14 Use the actual
computed crate name for -Zprint-vtable-sizes
rust-lang@1a1b10fa63 Don't steal the
parse query when using --pretty
rust-lang@6e33e89337 Remove from vacation
and compiler review group
rust-lang@38ff91c453 bump clang version
for dist-x86_64-linux from 17.0.2 to 17.0.4
rust-lang@86fca873ba Use the correct span
when emitting the `env!` result
rust-lang@c077147200 fix clippy author
and failing test
rust-lang@876f698790 Add the
vis.visit_capture_by() in noop_visit_expr
rust-lang@54ce0346c0 add `fn
visit_capture_by` to MutVisitor and fix pprust-expr-roundtrip.rs
rust-lang@df85b28b72 fixes for rustfmt +
ast visitor
rust-lang@a6b41aa6ba fmt
rust-lang@241a654c07 Fix remaining uses
of `CaptureBy::Value`
rust-lang@8de489918b feat(hir): Store the
`Span` of the `move` keyword
rust-lang@bee7b5889e Derive
TyEncodable/TyDecodable implementations that are parameterized over
interner
rust-lang@78aa5e511c detect EOF earlier
rust-lang@8d8f06b277 avoid excessive
initialization when copying to a Vec
rust-lang@666cad9a5f add test for rust-lang#113375
rust-lang@384f7382ba add test for rust-lang#113381
rust-lang@248dd14fa5 update
config.example.toml
rust-lang@bf5fb7614b update bootstrap
change history
rust-lang@ab8101d019 enable parallel
rustc in nightly builds
rust-lang@231f93524d Detect misparsed
binop caused by missing semi
rust-lang@98d54da1ee document that the
null pointer has the 0 address

---------

Co-authored-by: celinval <[email protected]>
Co-authored-by: Zyad Hassan <[email protected]>
Co-authored-by: Zyad Hassan <[email protected]>
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Document that null is 0