Stabilize LocalKey::try_with
The `LocalKey::try_with` method is now stabilized.
`LocalKey::state` and `LocalKeyState` marked as deprecated. Although, is there any reason to keep them - should we perhaps remove them completely?
Closes#27716
r? @alexcrichton
rustc: Tweak funclet cleanups of ffi functions
This commit is targeted at addressing #48251 by specifically fixing a case where
a longjmp over Rust frames on MSVC runs cleanups, accidentally running the
"abort the program" cleanup as well. Added in #46833 `extern` ABI functions in
Rust will abort the process if Rust panics, and currently this is modeled as a
normal cleanup like all other destructors.
Unfortunately it turns out that `longjmp` on MSVC is implemented with SEH, the
same mechanism used to implement panics in Rust. This means that `longjmp` over
Rust frames will run Rust cleanups (even though we don't necessarily want it
to). Notably this means that if you `longjmp` over a Rust stack frame then that
probably means you'll abort the program because one of the cleanups will abort
the process.
After some discussion on IRC it turns out that `longjmp` doesn't run cleanups
for *caught* exceptions, it only runs cleanups for cleanup pads. Using this
information this commit tweaks the codegen for an `extern` function to
a catch-all clause for exceptions instead of a cleanup block. This catch-all is
equivalent to the C++ code:
try {
foo();
} catch (...) {
bar();
}
and in fact our codegen here is designed to match exactly what clang emits for
that C++ code!
With this tweak a longjmp over Rust code will no longer abort the process. A
longjmp will continue to "accidentally" run Rust cleanups (destructors) on MSVC.
Other non-MSVC platforms will not rust destructors with a longjmp, so we'll
probably still recommend "don't have destructors on the stack", but in any case
this is a more surgical fix than #48567 and should help us stick to standard
personality functions a bit longer.
Fix find_width_of_character_at_span bounds check
Commit 0bd96671f0 added bounds checking of our current target byte position to prevent infinite loops. Unfortunately it was comparing the file-relative `target` versus the global `file_start_pos` and `file_end_pos`.
The result is failing to detect multibyte characters unless their file-relative offset fit within their global offset. This causes other parts of the compiler to generate spans pointing to the middle of a
multibyte character which will ultimately panic in `bytepos_to_file_charpos`.
Fix by comparing the `target` to the total file size when moving forward and doing checked subtraction when moving backwards. This should preserve the intent of the bounds check while removing the offset confusion.
cc @davidtwco
Fixes#48508
Support parentheses in patterns under feature gate
This is a prerequisite for any other extensions to pattern syntax - `|` with multiple patterns, type ascription, `..PAT` in slice patterns.
Closes https://github.com/rust-lang/rfcs/issues/554
[Underspecified semantics] Type check defaults at declaration.
Fixes #46669. See the test for code that compiles on stable but will no longer compile. This falls under a "Underspecified language semantics" fix. **Needs crater**.
On type and trait declarations, we currently allow anything that name checks as a type parameter default. That allows the user to write a default that can never be applied, or even a default that may conditionally be applied depending on the type of another parameter. Mostly this just defers the error to use sites, but also allows clever hacks such as `Foo<T, U = <T as Iterator>::Item>` where `U` will be able to apply it's default only when `T: Iterator`. Maybe that means this bug is a feature, but it's a fiddly behaviour that seems undesirable.
This PR validates defaults at declaration sites by ensuring all predicates on the parameter are valid for the default. With the exception of `Self: Sized` which we don't want to check to allow things like `trait Add<RHS = Self>`.
This commit is targeted at addressing #48251 by specifically fixing a case where
a longjmp over Rust frames on MSVC runs cleanups, accidentally running the
"abort the program" cleanup as well. Added in #46833 `extern` ABI functions in
Rust will abort the process if Rust panics, and currently this is modeled as a
normal cleanup like all other destructors.
Unfortunately it turns out that `longjmp` on MSVC is implemented with SEH, the
same mechanism used to implement panics in Rust. This means that `longjmp` over
Rust frames will run Rust cleanups (even though we don't necessarily want it
to). Notably this means that if you `longjmp` over a Rust stack frame then that
probably means you'll abort the program because one of the cleanups will abort
the process.
After some discussion on IRC it turns out that `longjmp` doesn't run cleanups
for *caught* exceptions, it only runs cleanups for cleanup pads. Using this
information this commit tweaks the codegen for an `extern` function to
a catch-all clause for exceptions instead of a cleanup block. This catch-all is
equivalent to the C++ code:
try {
foo();
} catch (...) {
bar();
}
and in fact our codegen here is designed to match exactly what clang emits for
that C++ code!
With this tweak a longjmp over Rust code will no longer abort the process. A
longjmp will continue to "accidentally" run Rust cleanups (destructors) on MSVC.
Other non-MSVC platforms will not rust destructors with a longjmp, so we'll
probably still recommend "don't have destructors on the stack", but in any case
this is a more surgical fix than #48567 and should help us stick to standard
personality functions a bit longer.
Given a trait predicate, if all params appearing in the LHS have
defaults then it should be a backwards compatible predicate. We verify
that by checking the WF of predicate with all defaults substituted
simultaneously.
Ensure main() always has external linkage
This ensures that the entry function is never elided due to inlining, even with `inline(always)`. Fixes#47783.
There were a couple of possible ways of addressing this issue; I simply picked the one that seemed most direct. A warning could be appropriate, but considering using inlining hints in other places it doesn't apply also throws no warnings, and it seems like an edge case anyway, I haven't added one for now.
Restrict the Termination impls to simplify stabilization
Make a minimal commitment in preparation for stabilization. More impls, or broader ones, are likely in future, but are not necessary at this time and are more controversial.
cc https://github.com/rust-lang/rust/issues/48453#issuecomment-368155082
r? @nikomatsakis
Add support for powerpc-unknown-linux-gnuspe
This PR adds support for the embedded PowerPC variant "e500". On Linux, this architecture is usually called "powerpcspe", it is a 32-bit PowerPC architecture. The main difference between normal 32-bit PowerPC and PowerPCSPE is the lack of Altivec instructions and the additional SPE instruction set.
This architecture is supported in Debian through an unofficial port.
Comprehensively support trailing commas in std/core macros
I carefully organized the changes into four commits:
* Test cases
* Fixes for `macro_rules!` macros
* Fixes for builtin macros
* Docs for builtins
**I can easily scale this back to just the first two commits for now if such is desired.**
### Breaking (?) changes
* This fixes#48042, which is a breaking change that I hope people can agree is just a bugfix for an extremely dark corner case.
* To fix five of the builtins, this changes `syntax::ext::base::get_single_str_from_tts` to accept a trailing comma, and revises the documentation so that this aspect is not surprising. **I made this change under the (hopefully correct) understanding that `libsyntax` is private rustc implementation detail.** After reviewing all call sites (which were, you guessed it, *precisely those five macros*), I believe the revised semantics are closer to the intended spirit of the function.
### Changes which may require concensus
Up until now, it could be argued that some or all the following macros did not conceptually take a comma-separated list, because they only took one argument:
* **`cfg(unix,)`** (most notable since cfg! is unique in taking a meta tag)
* **`include{,_bytes,_str}("file.rs",)`** (in item form this might be written as "`include!{"file.rs",}`" which is even slightly more odd)
* **`compile_error("message",);`**
* **`option_env!("PATH",)`**
* **`try!(Ok(()),)`**
So I think these particular changes may require some sort of consensus. **All of the fixes for builtins are included this list, so if we want to defer these decisions to later then I can scale this PR back to just the first two commits.**
### Other notes/general requests for comment
* Do we have a big checklist somewhere of "things to do when adding macros?" My hope is for `run-pass/macro-comma-support.rs` to remain comprehensive.
* Originally I wanted the tests to also comprehensively forbid double trailing commas. However, this didn't work out too well: [see this gist and the giant FIXME in it](https://gist.github.com/ExpHP/6fc40e82f3d73267c4e590a9a94966f1#file-compile-fail_macro-comma-support-rs-L33-L50)
* I did not touch `select!`. It appears to me to be a complete mess, and its trailing comma mishaps are only the tip of the iceberg.
* There are [some compile-fail test cases](5fa97c35da/src/test/compile-fail/macro-comma-behavior.rs (L49-L52)) that didn't seem to work (rustc emits errors, but compile-fail doesn't acknowledge them), so they are disabled. Any clues? (Possibly related: These happen to be precisely the set of errors which are tagged by rustc as "this error originates in a macro outside of the current crate".)
---
Fixes#48042Closes#46241
Rustc explain
Fixes#48041.
To make the review easier, I separated tests update to code update. Also, I used this script to generate new ui tests stderr:
```python
from os import listdir
from os.path import isdir, isfile, join
PATH = "src/test/ui"
def do_something(path):
files = [join(path, f) for f in listdir(path)]
for f in files:
if isdir(f):
do_something(f)
continue
if not isfile(f) or not f.endswith(".stderr"):
continue
x = open(f, "r")
content = x.read().strip()
if "error[E" not in content:
continue
errors = dict()
for y in content.splitlines():
if y.startswith("error[E"):
errors[y[6:11]] = True
errors = sorted(errors.keys())
if len(errors) < 1:
print("weird... {}".format(f))
continue
if len(errors) > 1:
content += "\n\nYou've got a few errors: {}".format(", ".join(errors))
content += "\nIf you want more information on an error, try using \"rustc --explain {}\"".format(errors[0])
else:
content += "\n\nIf you want more information on this error, try using \"rustc --explain {}\"".format(errors[0])
content += "\n"
x = open(f, "w")
x.write(content)
do_something(PATH)
```
This is named for the issue as it's testing the specific details of that
bug. It's a bit tricky as the ICE requires multiple files and debug info
enabled to trigger.
This ensures that the entry function is never elided due to inlining, even with `inline(always)`. Fixes#47783.
There were a couple of possible ways of addressing this issue; I simply picked the one that seemed most direct. A warning could be appropriate, but considering using inlining hints in other places it doesn't apply also throws no warnings, and it seems like an edge case anyway, I haven't added one for now.
