rustbuild: support MIPS host builds
There is a *little* code duplication, but primarily for sake of "match exhaustiveness". Let's blame Linux/MIPS for not exposing endianness explicitly in `uname -m` (that's user-space interface and as such is frozen).
Currently the build won't work as we have to wait for a new stage0 for the MIPS host compilers, but this paves the way to self-hosted Rust on MIPS. The cross-compiled MIPS binaries are confirmed to work on the Loongson 3A2000 (MIPS64r2-compatible) so we have plenty of confidence that they'll work on other MIPS platforms too, as Linux/MIPS user-space ABI is consistent across machines of the same bitness.
r? @alexcrichton
Remove mention of mipsel target_arch
This is the only remaining instance in rustc. All others were in the libc repo, removed with rust-lang/libc#445.
Actually there's more to clean in `libsyntax/abi.rs`, but let's save that for another commit...
Fix Arc::clone()'s MAX_REFCOUNT check (off-by-one)
Before, the strong count of an `Arc` could be set to
`MAX_REFCOUNT + 1`, because when this happened, `old_size` would
be exactly `MAX_REFCOUNT`. `Arc::clone()` would not abort.
This commit changes the check in `Arc::clone()` to also abort if
the old value is equal to `MAX_REFCOUNT`, because then the new
value will be equal to `MAX_REFCOUNT + 1`.
A test would require allocating memory for `isize::MAX` pointers.
This would probably crash any machine, so no test is submitted
with this commit.
There is a *little* code duplication, but primarily for sake of "match
exhaustiveness". Let's blame Linux/MIPS for not exposing endianness
explicitly in `uname -m` (that's user-space interface and as such is
frozen).
Currently the build won't work as we have to wait for a new stage0 for
the MIPS host compilers, but this paves the way to self-hosted Rust on
MIPS. The cross-compiled MIPS binaries are confirmed to work on the
Loongson 3A2000 (MIPS64r2-compatible) so we have plenty of confidence
that they'll work on other MIPS platforms too, as Linux/MIPS user-space
ABI is consistent across machines of the same bitness.
The `mipsel` `target_arch` was introduced with the initial MIPSel
support (rust-lang/rust@82ec1aef29),
but was subsequently removed with implementation of the Flexible Target
Specification (Rust RFC 0131,
rust-lang/rust@3a8f4ec32a).
This is the only remaining instance in rustc. All others are in the libc
repo, and are fixed in rust-lang/libc@b3676593f6.
macros: improve shadowing checks
This PR improves macro-expanded shadowing checks to work with out-of-(pre)order expansion.
Out-of-order expansion became possible in #37084, so this technically a [breaking-change] for nightly.
The regression test from this PR is an example of code that would break.
r? @nrc
Force static linking of LLVM
Run `llvm-config` with `--link-static` if available, to force static linking of LLVM.
This option was added in LLVM 3.8.
This is my first pull request, any feedback is welcome!
Fixes#36854
See also: #36996
The constant name `MAX_REFCOUNT` suggests that the value is a
_hard_ limit on the amount of references to an `Arc`. This is
a more soft limit however. This commit adds a comment to the
constant to annotate this.
See also: PR #37605
[4/n] rustc: harden against InferOk having obligations in more cases.
_This is part of a series ([prev](https://github.com/rust-lang/rust/pull/37402) | [next](https://github.com/rust-lang/rust/pull/37408)) of patches designed to rework rustc into an out-of-order on-demand pipeline model for both better feature support (e.g. [MIR-based](https://github.com/solson/miri) early constant evaluation) and incremental execution of compiler passes (e.g. type-checking), with beneficial consequences to IDE support as well.
If any motivation is unclear, please ask for additional PR description clarifications or code comments._
<hr>
This adds more asserts that `InferOk` results have no obligations, pending completion of #32730.
Each of these could accidentally drop obligations on the floor if they start getting produced by unification, and a future change does just that, in order to produce a "shallow success" (hopefully leading to ambiguities during trait selection), _without_ the possibility of an eventual success - mostly guarded by ICEs for now.
Add example using Self to reference
When I first came across `Self` I had a hard time finding references to it in the docs (and it's also been asked about on [StackOverflow](http://stackoverflow.com/questions/32304595/whats-the-difference-between-self-and-self).
I hope this example provides someone who comes across it for the first time a little more help. If there is a better way to show an example actually using `Self`, I'm happy to modify this. It was just the simplest place to start I could see.
std: Track change to cprng syscall signature (Fuchsia)
The mx_cprng_draw syscall has changed signature to separate the status
and size return values, rather than multiplexing them into a single
value with errors interpreted as a negative value. This patch tracks
that change.
Fix issues with the Add/AddAssign impls for Cow<str>
* Correct the stability attributes.
* Make Add and AddAssign actually behave the same.
* Use String::with_capacity when allocating a new string.
* Fix the tests.
Fix ICE when querying DefId on Def::Err.
Also moves computations into check that `kind_id` is `Ok(_)`, which is in theory an optimization, though I expect it's minor.
Fixes#37534.
r? @eddyb.
set frame pointer elimination attribute for main
The rustc-generated function `main` should respect the same config for
frame pointer elimination as the rest of code.
