Add #[repr(transparent)] to Atomic* types
This allows them to be used in `#[repr(C)]` structs without warnings. Since rust-lang/rfcs#1649 and rust-lang/rust#35603 they are already documented to have "the same in-memory representation as" their corresponding primitive types. This just makes that explicit.
This was briefly part of #51395, but was controversial and therefore dropped. But it turns out that it's essentially already documented (which I had forgotten).
Clarifying how the alignment of the struct works
The docs were not specifying how to compute the alignment of the struct, so I had to spend some time trying to figure out how that works. Found the answer [on this page](http://camlorn.net/posts/April%202017/rust-struct-field-reordering.html):
> The total size of this struct is 5, but the most-aligned field is b with alignment 2, so we round up to 6 and give the struct an alignment of 2 bytes.
NLL: fix E0594 "change to mutable ref" suggestion
Fix#51515.
Fix#51879.
Questions:
- [x] Is this the right place to fix this? It feels brittle, being so close to the frontend. **It's probably fine.**
- [ ] Have I missed any other cases that trigger this behavior?
- [x] Is it okay to use HELP and SUGGESTION in the UI test? **Yes.**
- [x] Do I need more tests for this? **No.**
This commit upgrades the main LLVM submodule to LLVM's current master branch.
The LLD submodule is updated in tandem as well as compiler-builtins.
Along the way support was also added for LLVM 7's new features. This primarily
includes the support for custom section concatenation natively in LLD so we now
add wasm custom sections in LLVM IR rather than having custom support in rustc
itself for doing so.
Some other miscellaneous changes are:
* We now pass `--gc-sections` to `wasm-ld`
* The optimization level is now passed to `wasm-ld`
* A `--stack-first` option is passed to LLD to have stack overflow always cause
a trap instead of corrupting static data
* The wasm target for LLVM switched to `wasm32-unknown-unknown`.
* The syntax for aligned pointers has changed in LLVM IR and tests are updated
to reflect this.
* The `thumbv6m-none-eabi` target is disabled due to an [LLVM bug][llbug]
Nowadays we've been mostly only upgrading whenever there's a major release of
LLVM but enough changes have been happening on the wasm target that there's been
growing motivation for quite some time now to upgrade out version of LLD. To
upgrade LLD, however, we need to upgrade LLVM to avoid needing to build yet
another version of LLVM on the builders.
The revision of LLVM in use here is arbitrarily chosen. We will likely need to
continue to update it over time if and when we discover bugs. Once LLVM 7 is
fully released we can switch to that channel as well.
[llbug]: https://bugs.llvm.org/show_bug.cgi?id=37382
NLL: fix E0594 "change to mutable ref" suggestion
Fix#51515.
Fix#51879.
Questions:
- [x] Is this the right place to fix this? It feels brittle, being so close to the frontend. **It's probably fine.**
- [ ] Have I missed any other cases that trigger this behavior?
- [x] Is it okay to use HELP and SUGGESTION in the UI test? **Yes.**
- [x] Do I need more tests for this? **No.**
rustdoc: Hide struct and enum variant constructor imports
This is fallout from #51425. The duplicate variant imports can be seen [here](https://doc.rust-lang.org/nightly/std/prelude/v1/index.html) for example.
This is fixing a regression so could be backported to beta.
r? @QuietMisdreavus
It wasn't abundantly clear to me what `.take` returned. Perhaps this is a slightly frivolous change, but I think it's an improvement. =)
Apologies if I'm not following proper procedures.
Implement #[alloc_error_handler]
This to-be-stable attribute is equivalent to `#[lang = "oom"]`. It is required when using the `alloc` crate without the `std` crate. It is called by `handle_alloc_error`, which is in turned called by "infallible" allocations APIs such as `Vec::push`.
If you are using a hard-linked file as your config.toml, this change will affect the way other instances of the file is modified.
The original version would modify all other instances whereas the new version will leave others unchanged, reducing the ref count by one.
Signed-off-by: NODA, Kai <nodakai@gmail.com>
find and highlight the `&` or `'_` in `region_name`
Before:
```
--> $DIR/dyn-trait-underscore.rs:18:5
|
LL | fn a<T>(items: &[T]) -> Box<dyn Iterator<Item=&T>> {
- | ----- lifetime `'1` appears in this argument
LL | Box::new(items.iter()) //~ ERROR cannot infer an appropriate lifetime
| ^^^^^^^^^^^^^^^^^^^^^^ cast requires that `'1` must outlive `'static`
```
After:
```
--> $DIR/dyn-trait-underscore.rs:18:5
|
LL | fn a<T>(items: &[T]) -> Box<dyn Iterator<Item=&T>> {
+ | - let's call the lifetime of this reference `'1`
LL | Box::new(items.iter()) //~ ERROR cannot infer an appropriate lifetime
| ^^^^^^^^^^^^^^^^^^^^^^ cast requires that `'1` must outlive `'static`
```
Not intended as the final end point necessarily in any sense. I intentionally left some to-do points to fill in later:
- Does not apply to upvars in closures yet (should be relatively easy)
- Does not handle the case where we can't find a precise match very well
- And of course we can still tweak wording
but shows the basic idea of how to make the `Ty` and `hir::Ty` to find a good spot to highlight.
r? @estebank
cc @davidtwco
Warn windows-gnu users that the bundled gcc can't compile
Add a `DO NOT USE THIS gcc.exe FOR COMPILATION.txt` file to `lib\rustlib\*-pc-windows-gnu\bin` folders in `windows-gnu` installations in order to warn against attempting to use the bundled `gcc.exe` as a C compiler. I'm pretty sure that location is usually found manually, so this should be easily noticeable.
This mistake has been made plenty of times and has lead to misunderstandings:
Rust: [Bundled gcc (windows x64) is unable to build any c file](https://github.com/rust-lang/rust/issues/24418)
gtk-rs: [Compiling on windows](https://github.com/gtk-rs/gtk/issues/625)
bzip2-rs: [Build failure at gcc level: blocksort.c not found](https://github.com/alexcrichton/bzip2-rs/issues/30)
Alternatives: rename the bundled `gcc.exe` to e.g. `rustc-gcc.exe` or `gcc-linker.exe`. This might require a more comprehensive change or break crates already using it as a linker.
r? @alexcrichton
Store scalar pair bools as i8 in memory
We represent `bool` as `i1` in a `ScalarPair`, unlike other aggregates,
to optimize IR for checked operators and the like. With this patch, we
still do so when the pair is an immediate value, but we use the `i8`
memory type when the value is loaded or stored as an LLVM aggregate.
So `(bool, bool)` looks like an `{ i1, i1 }` immediate, but `{ i8, i8 }`
in memory. When a pair is a direct function argument, `PassMode::Pair`,
it is still passed using the immediate `i1` type, but as a return value
it will use the `i8` memory type. Also, `bool`-like` enum tags will now
use scalar pairs when possible, where they were previously excluded due
to optimization issues.
Fixes#51516.
Closes#51566.
r? @eddyb
cc @nox
Haiku: work around the lack of setrlimit
The default Unix codepath fails, because Haiku does not implement
setrlimit for stack size. Thus we create an additional path.
By default, Haiku has the desired 16 MB stack, therefore in general
we do not have to spawn a new thread. The code has been written in
such a way that any changes in Haiku or in Rust will be adapted to.
This issue was reported to security@rust-lang.org by Sebastien Marie following
our recent [security advisory][1]. Because `/tmp` is typically globally writable
it's possible for one user to place symlinks in `/tmp` pointing to files in
another user's directories, causing `rustc` to overwrite the contents of
innocent files by accident.
This patch instead defaults the output path here to the cwd which should avoid
this issue.
[1]: https://blog.rust-lang.org/2018/07/06/security-advisory-for-rustdoc.html
This to-be-stable attribute is equivalent to `#[lang = "oom"]`.
It is required when using the alloc crate without the std crate.
It is called by `handle_alloc_error`, which is in turned called
by "infallible" allocations APIs such as `Vec::push`.
This turned out to be important on Windows.
Calling `handle_alloc_error(Layout:🆕:<[u8; 42]>())` caused:
```
Exception thrown at 0x00007FF7C70DC399 in a.exe: 0xC0000005:
Access violation reading location 0x000000000000002A.
```
0x2A equals 42, so it looks like the `Layout::size` field of type `usize`
was interpreted as a pointer to read from.
Add the `alloc::prelude` module
It contains the re-exports that are in `std::prelude::v1` but not in `core::prelude::v1`.
Calling it prelude is somewhat of a misnomer since (unlike those modules in `std` or `core`) its contents are never implicitly imported in modules. Rather it is intended to be used with an explicit glob import like `use alloc::prelude::*;`. However there is precedent for the same misnomer with `std::io::prelude`, for example.
This new module is unstable with the same feature name as the `alloc` care. They are proposed for stabilization together in RFC https://github.com/rust-lang/rfcs/pull/2480.
