Use a u64 for the rmeta root position
Waffle noticed this in https://github.com/rust-lang/rust/pull/117301#discussion_r1405410174
We've upgraded the other file offsets to u64, and this one only costs 4 bytes per file. Also the way the truncation was being done before was extremely easy to miss, I sure missed it! It's not clear to me if not having this change effectively made the other upgrades from u32 to u64 ineffective, but we can have it now.
r? `@WaffleLapkin`
Add lint against ambiguous wide pointer comparisons
This PR is the resolution of https://github.com/rust-lang/rust/issues/106447 decided in https://github.com/rust-lang/rust/issues/117717 by T-lang.
## `ambiguous_wide_pointer_comparisons`
*warn-by-default*
The `ambiguous_wide_pointer_comparisons` lint checks comparison of `*const/*mut ?Sized` as the operands.
### Example
```rust
let ab = (A, B);
let a = &ab.0 as *const dyn T;
let b = &ab.1 as *const dyn T;
let _ = a == b;
```
### Explanation
The comparison includes metadata which may not be expected.
-------
This PR also drops `clippy::vtable_address_comparisons` which is superseded by this one.
~~One thing: is the current naming right? `invalid` seems a bit too much.~~
Fixes https://github.com/rust-lang/rust/issues/117717
We don't really want to communicate with target maintainers via email.
GitHub is where everything happens, people should have a GitHub account
that can be pinged on issues.
This doesn't necessarily have to be a strict rule, but edit the template
to suggest this. The previous template made it look like we care about
having an email address, which we do not.
To ensure deterministic results we must sort the dump lines.
This is necessary because the order of rustc invocations different
almost all the time.
Signed-off-by: onur-ozkan <work@onurozkan.dev>
When making changes to the bootstrap that shouldn't change its behavior,
this feature will help developers perform comparisons to check whether the
bootstrap behavior has changed or not.
This can also be used for different purposes. For example, allowing CI to
dump the shims and upload them so that developers can download them and compare
with their local dump to see if CI affects the bootstrap unexpectedly. Or, make CI
perform comparisons on specific bootstrap tests to check for behavior changes between
the master and PR branches.
Signed-off-by: onur-ozkan <work@onurozkan.dev>
Remove edition umbrella features.
In the 2018 edition, there was an "umbrella" feature `#[feature(rust_2018_preview)]` which was used to enable several other features at once. This umbrella mechanism was not used in the 2021 edition and likely will not be used in 2024 either. During 2018 users reported that setting the feature was awkward, especially since they already needed to opt-in via the edition mechanism.
This PR removes this mechanism because I believe it will not be used (and will clean up and simplify the code). I believe that there are better ways to handle features and editions. In short:
- For highly experimental features, that may or may not be involved in an edition, they can implement regular feature gates like `tcx.features().my_feature`.
- For experimental features that *might* be involved in an edition, they should implement gates with `tcx.features().my_feature && span.at_least_rust_20xx()`. This requires the user to still specify `#![feature(my_feature)]`, to avoid disrupting testing of other edition features which are ready and have been accepted within the edition.
- For experimental features that have graduated to definitely be part of an edition, they should implement gates with `tcx.features().my_feature || span.at_least_rust_20xx()`, or just remove the feature check altogether and just check `span.at_least_rust_20xx()`.
- For relatively simple changes, they can skip the whole feature gating thing and just check `span.at_least_rust_20xx()`, and rely on the instability of the edition itself (which requires `-Zunstable-options`) to gate it.
I am working on documenting all of this in the rustc-dev-guide.
guarantee that char and u32 are ABI-compatible
In https://github.com/rust-lang/rust/pull/116894 we added a guarantee that `char` has the same alignment as `u32`, but there is still one axis where these types could differ: function call ABI. So let's nail that down as well: in a function signature, `char` and `u32` are completely equivalent.
This is a new stable guarantee, so it will need t-lang approval.
Revert using MCP510 in bootstrap
This reverts commit 40c3d351ad. The commit started dogfooding MCP510 to enable `lld` when building the compiler , but it broke tests, because we don't pass `-Zunstable-options` on enough places. This PR hotfixes that, and temporarily makes the "self-contained" option.. not very self-contained. I'll send a proper fix later, but I want to unblock rustc developres that use `lld` locally.
r? `@nnethercote` (who discovered the problem)
This is an extension of the previous commit. It means the output of
something like this:
```
stringify!(let a: Vec<u32> = vec![];)
```
goes from this:
```
let a: Vec<u32> = vec![] ;
```
With this PR, it now produces this string:
```
let a: Vec<u32> = vec![];
```
This reverts commit 40c3d351ad. The option was dogfooded for using lld with MCP510 , but it broke testing with LLD, because we don't pass `-Zunstable-options` on enough places.
Return MAP_FAILED when mmap fails
I don't properly remember why we ended up with a hodgepodge of return values, but https://github.com/rust-lang/miri/issues/3218 correctly points out that we are supposed to return `MAP_FAILED`. This should fix that return value and also add sufficient tests to prevent making a similar mistake.
Implement `--env` compiler flag (without `tracked_env` support)
Part of https://github.com/rust-lang/rust/issues/80792.
Implementation of https://github.com/rust-lang/compiler-team/issues/653.
Not an implementation of https://github.com/rust-lang/rfcs/pull/2794.
It adds the `--env` compiler flag option which allows to set environment values used by `env!` and `option_env!`.
Important to note: When trying to retrieve an environment variable value, it will first look into the ones defined with `--env`, and if there isn't one, then only it will look into the environment variables. So if you use `--env PATH=a`, then `env!("PATH")` will return `"a"` and not the actual `PATH` value.
As mentioned in the title, `tracked_env` support is not added here. I'll do it in a follow-up PR.
r? rust-lang/compiler
Fix miri script target dir and update doc link
Fix ui_test doc link in `CONTRIBUTING.md`
Explicitly set `--target-dir` in `miri` script when building to expected location
- I have `build.target-dir` cargo config set to be some other location so miri script was erroring out since compiled binary was not in expected location
Generalize LLD usage in bootstrap
The current usage of using LLD (`rust.use-lld = true`) in bootstrap is a bit messy. What it claimed:
> Indicates whether LLD will be used to link Rust crates during bootstrap on
> supported platforms. The LLD from the bootstrap distribution will be used
> and not the LLD compiled during the bootstrap.
What it did:
1) On MSVC, it did indeed use the snapshot compiler's `rust-lld`, but at the same time it was invoking a global `lld` binary (since https://github.com/rust-lang/rust/pull/102101), therefore it wouldn't work if `lld` wasn't available.
2) On other targets, it was just straight up using a global `lld` linker. If it wasn't available, it would fail.
This PR (hopefully) cleans up handling of LLD in bootstrap. It introduces a new enum called `LldMode`, which explicitly distinguishes between no LLD, external LLD and self-contained LLD. Since it's non-trivial to provide a custom path to LLD, if an external `lld` is used, the linker binary has to be named exactly `lld` and it has to be available in PATH.
In addition, this PR also dog-foods [MCP510](https://github.com/rust-lang/compiler-team/issues/510) in bootstrap.
To keep backwards compatibility somewhat, I kept the original `use-lld` flag and mapped the `true` value to `"external"`, which is how it behaved before on Linux and other non-MSVC targets.
Having the option to use an external `lld` on Linux should come in handy for testing on CI once MCP510 sets the default linker on Linux to `lld`.
Note that thanks to MCP510, currently "self-contained" means that `lld` is used from the stage N-1 compiler (before, we always used `lld` from the snapshot/stage0 compiler).
Best reviewed commit by commit.
CC `@petrochenkov`
remove redundant imports
detects redundant imports that can be eliminated.
for #117772 :
In order to facilitate review and modification, split the checking code and removing redundant imports code into two PR.
r? `@petrochenkov`
detects redundant imports that can be eliminated.
for #117772 :
In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.
Rollup of 5 pull requests
Successful merges:
- #117966 (add safe compilation options)
- #118747 (Remove extra check cfg handled by libc directly)
- #118774 (add test for inductive cycle hangs)
- #118775 (chore: add test case for type with generic)
- #118782 (use `&` instead of start-process in x.ps1)
r? `@ghost`
`@rustbot` modify labels: rollup
