Stabilize asm! and global_asm!
Tracking issue: #72016
It's been almost 2 years since the original [RFC](https://github.com/rust-lang/rfcs/pull/2850) was posted and we're finally ready to stabilize this feature!
The main changes in this PR are:
- Removing `asm!` and `global_asm!` from the prelude as per the decision in #87228.
- Stabilizing the `asm` and `global_asm` features.
- Removing the unstable book pages for `asm` and `global_asm`. The contents are moved to the [reference](https://github.com/rust-lang/reference/pull/1105) and [rust by example](https://github.com/rust-lang/rust-by-example/pull/1483).
- All links to these pages have been removed to satisfy the link checker. In a later PR these will be replaced with links to the reference or rust by example.
- Removing the automatic suggestion for using `llvm_asm!` instead of `asm!` if you're still using the old syntax, since it doesn't work anymore with `asm!` no longer being in the prelude. This only affects code that predates the old LLVM-style `asm!` being renamed to `llvm_asm!`.
- Updating `stdarch` and `compiler-builtins`.
- Updating all the tests.
r? `@joshtriplett`
Looser check for overflowing_binary_op
Fix for issue #91636 tight check resulted in ICE, this makes the check a little looser. It seems `eq` allows comparing of `supertype` and `subtype` if `lhs = supertype` and `rhs = subtype` but not vice versa, is this intended behavior ?
Return an error when `eval_rvalue_with_identities` fails
Previously some code paths would fail to evaluate the rvalue, while
incorrectly indicating success with `Ok`. As a result the previous value
of lhs could have been incorrectly const propagated.
Fixes#91725.
r? `@oli-obk`
Recover on invalid operators `<>` and `<=>`
Thanks to #89871 for showing me how to do this.
Next, I think it'd be nice to recover on `<=>` too, like #89871 intended, if this even works.
Previously some code paths would fail to evaluate the rvalue, while
incorrectly indicating success with `Ok`. As a result the previous value
of lhs could have been incorrectly const propagated.
Suggest to specify a target triple when lang item is missing
It is very common for newbies to embedded to hit this confusing error when forgetting to specify the target.
Source: me googling this error many times.
## Possible changes
* We could possibly restrict the note+help to only be included on eh_personality lang item if that helped reduce false positives, but its also possible doing so would just increase false negatives
* Open to any suggestions on rewriting the messages
* We could possibly remove the `.cargo/config` alternative to avoid the message getting too noisy but I think its valuable to have as its the correct approach for most embedded projects so that `cargo build` just works.
r? rust-lang/diagnostics
manually implement `Hash` for `DefId`
This might speed up hashing for hashers that can work on individual u64s. Just as an experiment, suggested in a reddit thread on `FxHasher`. cc `@nnethercote`
Note that this should not be merged as is without cfg-ing the code path for 64 bits.
GATs outlives lint: Try to prove bounds
Fixes#91036Fixes#90888Fixes#91348 (better error + documentation to be added to linked issue)
Instead of checking for bounds directly, try to prove them in the associated type environment.
Also, add a bit of extra information to the error, including a link to the relevant discussion issue (#87479). That should be edited to include a brief summary of the current state of the outlives lint, including a brief background. It also might or might not be worth it to bump this to a full error code at some point.
r? ``@nikomatsakis``
Use module inline assembly to embed bitcode
In LLVM 14, our current method of setting section flags to avoid
embedding the `.llvmbc` section into final compilation artifacts
will no longer work, see issue #90326. The upstream recommendation
is to instead embed the entire bitcode using module-level inline
assembly, which is what this change does.
I've kept the existing code for platforms where we do not need to
set section flags, but possibly we should always be using the
inline asm approach (which would have to look a bit different for MachO).
r? `@nagisa`
replace dynamic library module with libloading
This PR deletes the `rustc_metadata::dynamic_lib` module in favor of the popular and better tested [`libloading` crate](https://github.com/nagisa/rust_libloading/).
We don't benefit from `libloading`'s symbol lifetimes since we end up leaking the loaded library in all cases, but the call-sites look much nicer by improving error handling and abstracting away some transmutes. We also can remove `rustc_metadata`'s direct dependencies on `libc` and `winapi`.
This PR also adds an exception for `libloading` (and its license) to tidy, so this will need sign-off from the compiler team.
Stabilise `feature(const_generics_defaults)`
`feature(const_generics_defaults)` is complete implementation wise and has a pretty extensive test suite so I think is ready for stabilisation.
needs stabilisation report and maybe an RFC 😅
r? `@lcnr`
cc `@rust-lang/project-const-generics`
They are also removed from the prelude as per the decision in
https://github.com/rust-lang/rust/issues/87228.
stdarch and compiler-builtins are updated to work with the new, stable
asm! and global_asm! macros.
