Use type based qualification for unions
Union field access is currently qualified based on the qualification of
a value previously assigned to the union. At the same time, every union
access transmutes the content of the union, which might result in a
different qualification.
For example, consider constants A and B as defined below, under the
current rules neither contains interior mutability, since a value used
in the initial assignment did not contain `UnsafeCell` constructor.
```rust
#![feature(untagged_unions)]
union U { i: u32, c: std::cell::Cell<u32> }
const A: U = U { i: 0 };
const B: std::cell::Cell<u32> = unsafe { U { i: 0 }.c };
```
To avoid the issue, the changes here propose to consider the content of
a union as opaque and use type based qualification for union types.
Fixes#90268.
`@rust-lang/wg-const-eval`
Consider indirect mutation during const qualification dataflow
Previously a local would be qualified if either one of two separate data
flow computations indicated so. First determined if a local could
contain the qualif, but ignored any forms of indirect mutation. Second
determined if a local could be mutably borrowed (and so indirectly
mutated), but which in turn ignored the qualif.
The end result was incorrect because the effect of indirect mutation was
effectivelly ignored in the all but the final stage of computation.
In the new implementation the indirect mutation is directly incorporated
into the qualif data flow. The local variable becomes immediately
qualified once it is mutably borrowed and borrowed place type can
contain the qualif.
In general we will now reject additional programs, program that were
prevously unintentionally accepted.
There are also some cases which are now accepted but were previously
rejected, because previous implementation didn't consider whether
borrowed place could have the qualif under the consideration.
Fixes#90124.
r? `@ecstatic-morse`
Revert "Add rustc lint, warning when iterating over hashmaps"
Fixes perf regressions introduced in https://github.com/rust-lang/rust/pull/90235 by temporarily reverting the relevant PR.
Improve perf measurements of `build_extern_trait_impl`
Before, it was only measuring one callsite of `build_impl`, and it
incremented the call count even if `build_impl` returned early because
the `did` was already inlined.
Now, it measures all calls, minus calls that return early.
Fixes incorrect handling of ADT's drop requirements
Fixes#90024 and a bunch of duplicates.
The main issue was just that the contract of `NeedsDropTypes::adt_components` was inconsistent; the list of types it might return were the generic parameters themselves or the fields of the ADT, depending on the nature of the drop impl. This meant that the caller could not determine whether a `.subst()` call was still needed on those types; it called `.subst()` in all cases, and this led to ICEs when the returned types were the generic params.
First contribution of more than a few lines, so feedback definitely appreciated.
Before, it was only measuring one callsite of `build_impl`, and it
incremented the call count even if `build_impl` returned early because
the `did` was already inlined.
Now, it measures all calls, minus calls that return early.
Union field access is currently qualified based on the qualification of
a value previously assigned to the union. At the same time, every union
access transmutes the content of the union, which might result in a
different qualification.
For example, consider constants A and B as defined below, under the
current rules neither contains interior mutability, since a value used
in the initial assignment did not contain `UnsafeCell` constructor.
```rust
#![feature(untagged_unions)]
union U { i: u32, c: std::cell::Cell<u32> }
const A: U = U { i: 0 };
const B: std::cell::Cell<u32> = unsafe { U { i: 0 }.c };
```
To avoid the issue, the changes here propose to consider the content of
a union as opaque and use type based qualification for union types.
Add hint for people missing `TryFrom`, `TryInto`, `FromIterator` import pre-2021
Adds a hint anytime a `TryFrom`, `TryInto`, `FromIterator` import is suggested noting that these traits are automatically imported in Edition 2021.
fix: inner attribute followed by outer attribute causing ICE
Fixes#87936, #88938, and #89971.
This removes the assertion that validates that there are no outer attributes following inner attributes. Where the inner attribute is invalid you get an actual error.
Add LLVM CFI support to the Rust compiler
This PR adds LLVM Control Flow Integrity (CFI) support to the Rust compiler. It initially provides forward-edge control flow protection for Rust-compiled code only by aggregating function pointers in groups identified by their number of arguments.
Forward-edge control flow protection for C or C++ and Rust -compiled code "mixed binaries" (i.e., for when C or C++ and Rust -compiled code share the same virtual address space) will be provided in later work as part of this project by defining and using compatible type identifiers (see Type metadata in the design document in the tracking issue #89653).
LLVM CFI can be enabled with -Zsanitizer=cfi and requires LTO (i.e., -Clto).
Thank you, `@eddyb` and `@pcc,` for all the help!
Rollup of 3 pull requests
Successful merges:
- #90154 (rustdoc: Remove `GetDefId`)
- #90232 (rustdoc: Use TTF based font instead of OTF for CJK glyphs to improve readability)
- #90278 (rustdoc: use better highlighting for *const, *mut, and &mut)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
rustdoc: Use TTF based font instead of OTF for CJK glyphs to improve readability
Due to Windows' implementation of font rendering, OpenType fonts can be distorted. So the existing font, Noto Sans KR, is not very readable on Windows. This PR improves readability of Korean glyphs on Windows.
## Before
## After
The fonts included in this PR are licensed under the SIL Open Font License and generated with these commands:
```sh
pyftsubset NanumBarunGothic.ttf \
--unicodes=U+AC00-D7AF,U+1100-11FF,U+3130-318F,U+A960-A97F,U+D7B0-D7FF \
--output-file=NanumBarunGothic.ttf.woff --flavor=woff
```
```sh
pyftsubset NanumBarunGothic.ttf \
--unicodes=U+AC00-D7AF,U+1100-11FF,U+3130-318F,U+A960-A97F,U+D7B0-D7FF \
--output-file=NanumBarunGothic.ttf.woff2 --flavor=woff2
```
r? ``@GuillaumeGomez``
Properly check `target_features` not to trigger an assertion
Fixes#89875
I think it should be a condition instead of an assertion to check if it's a register as it's possible that `reg` is a register class.
Also, this isn't related to the issue directly, but `is_target_supported` doesn't check `target_features` attributes. Is there any way to check it on rustc_codegen_llvm?
r? `@Amanieu`
Edit error messages for `rustc_resolve::AmbiguityKind` variants
Edit the language of the ambiguity descriptions for E0659. These strings now appear as notes.
Closes#79717.
Previously a local would be qualified if either one of two separate data
flow computations indicated so. First determined if a local could
contain the qualif, but ignored any forms of indirect mutation. Second
determined if a local could be mutably borrowed (and so indirectly
mutated), but which in turn ignored the qualif.
The end result was incorrect because the effect of indirect mutation was
effectivelly ignored in the all but the final stage of computation.
In the new implementation the indirect mutation is directly incorporated
into the qualif data flow. The local variable becomes immediately
qualified once it is mutably borrowed and borrowed place type can
contain the qualif.
In general we will now reject additional programs, program that were
prevously unintentionally accepted.
There are also some cases which are now accepted but were previously
rejected, because previous implementation didn't consider whether
borrowed place could have the qualif under the consideration.
Update books
## nomicon
3 commits in 2d66852a27c5d0ec50ae021820d1de22caa2b1bd..358e6a61d5f4f0496d0a81e70cdcd25d05307342
2021-10-07 19:00:37 +0900 to 2021-10-20 11:23:12 -0700
- Write a basic "call Rust from C" example (rust-lang/nomicon#296)
- Clarify the Safe vs. Unsafe Rust relationship (rust-lang/nomicon#294)
- Fix typo with respect to dangling pointer (rust-lang/nomicon#319)
## book
8 commits in eb1282ec444db94055fa9531b6f3f803e86bb382..fd9299792852c9a368cb236748781852f75cdac6
2021-09-16 21:17:09 -0400 to 2021-10-22 21:59:46 -0400
- Reword description to emphasize what return does in a match arm
- Correct backwards wording describing From impls. Fixesrust-lang/book#2829
- Remove multiple negatives, add examples. Fixesrust-lang/book#2833
- Fix capitalization in sidebar. Fixesrust-lang/book#2860
- fix quotes
- comments from nostarch and responses for chapter 2
- (rust-lang/book#2906)
- Merge pull request rust-lang/book#2892 from Enrico2/patch-1
## rust-by-example
1 commits in 9a60624fcad0140826c44389571dc622917cd632..27f1ff5e440ef78828b68ab882b98e1b10d9af32
2021-10-04 08:13:53 -0300 to 2021-10-13 08:04:40 -0300
- Added example of `impl Trait` as an argument (rust-lang/rust-by-example#1468)
## embedded-book
1 commits in 270fccd339e5972d9c900e788f197e81a0bcd956..51739471276b1776dea27cf562b974ef07e24685
2021-10-06 16:28:48 +0000 to 2021-10-17 16:48:42 +0000
- Fix typo in 'The Borrow Checker' (rust-embedded/book#305)
Emit description of the ambiguity as a note.
Co-authored-by: Noah Lev <camelidcamel@gmail.com>
Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Avoid a branch on key being local for queries that use the same local and extern providers
Currently based on https://github.com/rust-lang/rust/pull/85810 as it slightly conflicts with it. Only the last two commits are new.
This commit adds LLVM Control Flow Integrity (CFI) support to the Rust
compiler. It initially provides forward-edge control flow protection for
Rust-compiled code only by aggregating function pointers in groups
identified by their number of arguments.
Forward-edge control flow protection for C or C++ and Rust -compiled
code "mixed binaries" (i.e., for when C or C++ and Rust -compiled code
share the same virtual address space) will be provided in later work as
part of this project by defining and using compatible type identifiers
(see Type metadata in the design document in the tracking issue #89653).
LLVM CFI can be enabled with -Zsanitizer=cfi and requires LTO (i.e.,
-Clto).
