trans: Internalize symbols without relying on LLVM
This PR makes the compiler use the information gather by the trans collector in order to determine which symbols/trans-items can be made internal. This has the advantages:
+ of being LLVM independent,
+ of also working in incremental mode, and
+ of allowing to not keep all LLVM modules in memory at the same time.
This is in preparation for fixing issue #39280.
cc @rust-lang/compiler
Slew of builtin-attribute gating tests
Slew of builtin-attribute "gating" tests for issue #43106.
Some stray observations:
* I don't know if its a good thing that so many attributes allow inputs which are silently discarded. (I made heavy use of that in writing my tests, but that was more out of curiosity than necessity.)
* The difference between crate-level and non-crate-level behavior is quite significant in some cases. Definitely worth making sure one has tests for both cases. (Not as clear whether it was worthwhile trying the various other AST forms like `fn f()` vs `struct S;`)
* `#[no_builtins]` and `#[no_mangle]` occur twice on the `BUILTIN_ATTRIBUTES` list. Thats almost certainly a bug. (Filed as #43148)
* We are maximally liberal in what we allow for `#[test]` and `#[bench]` when one compiles without `--test`.
* We allow `#[no_mangle]` on arbitrary AST nodes, but only warn about potential misuse on `fn`
* We allow `#[cold]`, `#[must_use]`, `#[windows_subsystem]`, and `#[no_builtins]` on arbitrary AST nodes. I don't know off-hand what the semantics are for e.g. a `#[cold] type T = ...;`
* We allow crate-level `#![inline]`. That's probably a bug since its otherwise restricted to `fn` items
Unify rules about commas in match arms and semicolons in expressions
Original discussion: https://internals.rust-lang.org/t/syntax-of-block-like-expressions-in-match-arms/5025/7.
Currently, rust uses different rules to determine if `,` is needed after an expression in a match arm and if `;` is needed in an expression statement:
```Rust
fn stmt() {
# no need for semicolons
{ () }
if true { () } else { () }
loop {}
while true {}
}
fn match_arm(n: i32) {
match n {
1 => { () } # can omit comma here
2 => if true { () } else { () }, # but all other cases do need commas.
3 => loop { },
4 => while true {},
_ => ()
}
}
```
This seems weird: why would you want to require `,` after and `if`?
This PR unifies the rules. It is backwards compatible because it allows strictly more programs.
Support generic lifetime arguments in method calls
Fixes https://github.com/rust-lang/rust/issues/42403
Fixes https://github.com/rust-lang/rust/issues/42115
Lifetimes in a method call `x.f::<'a, 'b, T, U>()` are treated exactly like lifetimes in the equivalent UFCS call `X::f::<'a, 'b, T, U>`.
In addition, if the method has late bound lifetime parameters (explicit or implicit), then explicitly specifying lifetime arguments is not permitted (guarded by a compatibility lint).
[breaking-change] because previously lifetimes in method calls were accepted unconditionally.
r? @eddyb
Fix treatment of lifetimes defined in nested types during detection of late bound regions in signatures.
Do not replace substs with inference variables when "cannot specify lifetime arguments explicitly..." is reported as a lint.
Add support for dylibs with Address Sanitizer
Many applications use address sanitizer to assert correct behaviour of their programs. When using Rust with C, it's much more important to assert correct programs with tools like asan/lsan due to the unsafe nature of the access across an ffi boundary. However, previously only rust bin types could use asan. This posed a challenge for existing C applications that link or dlopen .so when the C application is compiled with asan.
This PR enables asan to be linked to the dylib and cdylib crate type. We alter the test to check the proc-macro crate does not work with -Z sanitizer=address. Finally, we add a test that compiles a shared object in rust, then another rust program links it and demonstrates a crash through the call to the library.
This PR is nearly complete, but I do require advice on the change to fix the -lasan that currently exists in the dylib test. This is required because the link statement is not being added correctly to the rustc build when -Z sanitizer=address is added (and I'm not 100% sure why)
Thanks,
The produced paths aren't stable between builds, since
reporting paths inside resolve, before resolve is finished
might produce paths resolved to type aliases instead of
the concrete type.
Compile-fail tests can match just parts of messages, so they
don't "suffer" from this issue.
This is just a workaround, the instability should be fixed
in the future.
We want the suggested replacement (which IDE tooling and such might offer to
automatically swap in) to, like, actually be correct: suggesting `MyVariant(x)`
when the actual fix is `MyEnum::MyVariant(x)` might be better than nothing, but
Rust is supposed to be the future of computing: we're better than better than
nothing.
As an exceptional case, we excise the prelude path, preferring to suggest
`Some` or `Ok` rather than `std::prelude::v1::Some` and
`std::prelude::v2::Ok`. (It's not worth the effort to future-proof against
hypothetical preludes v2, v3, &c.: we trust our successors to grep—excuse me,
ripgrep—for that.)
Also, don't make this preëmpt the existing probe-for-return-type suggestions,
despite their being looked unfavorably upon, at least in this situation
(https://github.com/rust-lang/rust/issues/42764#issuecomment-311388958): Cody
Schafer pointed out that that's a separate issue
(https://github.com/rust-lang/rust/pull/43178#issuecomment-314953229).
This is in the matter of #42764.
support pub(restricted) in thread_local! (round 2)
Resurrected #40984 now that the issue blocking it was fixed. Original description:
`pub(restricted)` was stabilized in #40556 so let's go!
Here is a [playground](https://play.rust-lang.org/?gist=f55f32f164a6ed18c219fec8f8293b98&version=nightly&backtrace=1).
I changed the interface of `__thread_local_inner!`, which is supposedly unstable but this is not checked for macros (#34097 cc @petrochenkov @jseyfried), so this may be an issue.
Thread local try with
https://github.com/rust-lang/rfcs/pull/2030 was turned into this PR (the RFC was closed, but it looks like just a PR should be good).
See also: state stabilization issue: #27716
`try_with` is used in two places in std: stdio and thread_info. In stdio, it would be better if the result was passed to the closure, but in thread_info, it's better as is where the result is returned from the function call. I'm not sure which is better, but I prefer the current way as it better represents the scope.
Implement Eq/Hash/Debug etc. for unsized tuples.
As I mentioned in [the comment in #18469](https://github.com/rust-lang/rust/issues/18469#issuecomment-306767422), the implementations of `PartialEq`, `Eq`, `PartialOrd`, `Ord`, `Debug`, `Hash` can be generalized to unsized tuples.
This is consistent with the `derive` behavior for unsized structs.
```rust
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Default, Hash)]
struct MyTuple<X, Y, Z: ?Sized>(X, Y, Z);
fn f(x: &MyTuple<i32, i32, [i32]>) {
x == x;
x < x;
println!("{:?}", x);
}
```
Questions:
- Need an RFC?
- Need a feature gate? I don't think it does because the unsized tuple coercion #42527 is feature-gated.
- I changed `builder.field($name);` into `builder.field(&$name);` in the `Debug` implementation to pass compilation. This won't affect the behavior because `Debug for &'a T` is a mere redirection to `Debug for T`. However, I don't know if it affects code size / performance.
`rustc_on_unimplemented` supports referring to trait
Add support to `rustc_on_unimplemented` to reference the full path of
the annotated trait. For the following code:
```rust
pub mod Bar {
#[rustc_on_unimplemented = "test error `{Self}` with `{Bar}` `{Baz}` `{Quux}` in `{Foo}`"]
pub trait Foo<Bar, Baz, Quux> {}
}
```
the error message will be:
```
test error `std::string::String` with `u8` `_` `u32` in `Bar::Foo`
```
Note different versions of same crate when absolute paths of different types match.
The current check to address #22750 only works when the paths of the mismatched types relative to the current crate are equal, but this does not always work if one of the types is only included through an indirect dependency. If reexports are involved, the indirectly included path can e.g. [contain private modules](https://github.com/rust-lang/rust/issues/22750#issuecomment-302755516).
This PR takes care of these cases by also comparing the *absolute* path, which is equal if the type hasn't moved in the module hierarchy between versions. A more coarse check would be to compare only the crate names instead of full paths, but that might lead to too many false positives.
Additionally, I believe it would be helpful to show where the differing crates came from, i.e. the information in `rustc::middle::cstore::CrateSource`, but I'm not sure yet how to nicely display all of that, so I'm leaving it to a future PR.
This still does not work on 32-bit archs because of an LLVM limitation,
but this is only an optimization, so let's push it on 64-bit only for now.
Fixes#37945
incr.comp.: Don't include span information in the ICH of type definitions
This should improve some of the `regex` tests on perf.rlo. Not including spans into the ICH is harmless until we also cache warnings. To really solve the problem, we need to do more refactoring (see #43088).
r? @nikomatsakis
