Miri: tweak error print

I started by adjusting the "invalid use of int as pointer" message (it wasn't really clear what is invalid about the use). But then I realized that these are all `Debug` impls we use for these errors, for some reason, so I fixed that to use `Display` instead.

~~This includes https://github.com/rust-lang/rust/pull/71590 (to get the `Display` impl for `Pointer`), so the diff will look better once that finally lands. Here's the [relative diff](https://github.com/RalfJung/rust/compare/e72ebf5119e833b70231c3f2f8c7ca4904b1f0a3...RalfJung:miri-error-print).~~

r? @oli-obk

also tweak InvalidDiscriminant message

Disable localization for all linkers

We previously disabled non-English output from `link.exe` due to encoding issues (#35785).

In https://github.com/rust-lang/rust/pull/70740 it was pointed out that it also prevents correct inspection of the linker output, which we have to do occasionally.

So this PR disables localization for all linkers.

Have the per-query caches store the results on arenas

This PR leverages the cache for each query to serve as storage area for the query results.

It introduces a new cache `ArenaCache`, which moves the result to an arena,
and only stores the reference in the hash map.
This allows to remove a sizeable part of the usage of the global `TyCtxt` arena.

I only migrated queries that already used arenas before.

Rollup of 8 pull requests

Successful merges:

 - #71148 (Vec drop and truncate: drop using raw slice *mut [T])
 - #71465 (Add a convenience method on `TyCtxt` for checking for thread locals)
 - #71567 (Handle build completion message from Cargo)
 - #71590 (MIR dump: print pointers consistently with Miri output)
 - #71682 (Bump pulldown-cmark)
 - #71688 (Allow `Downcast` projections unconditionally in const-checking)
 - #71691 (Allow `Unreachable` terminators unconditionally in const-checking)
 - #71719 (Update backtrace-sys)

Failed merges:

r? @ghost

Update backtrace-sys

Diff:

- Don't look for old RUSTC_DEBUGINFO vars (rust-lang/backtrace-rs#313)

This fixes an issue of libbacktrace never being built with debuginfo.

r? @Mark-Simulacrum
cc @alexcrichton

Allow `Unreachable` terminators unconditionally in const-checking

If we ever actually reach an `Unreachable` terminator while executing, the MIR is ill-formed or the user's program is UB due to something like `unreachable_unchecked`. I don't think we need to forbid these in `qualify_min_const_fn`.

r? @oli-obk

Allow `Downcast` projections unconditionally in const-checking

`ProjectionElem::Downcast` sounds scary, but it's really just the projection we use to access a particular enum variant. They usually appear in the lowering of a `match` statement, so they have been associated with control flow in const-checking, but they don't do any control flow by themselves. We already have a HIR pass that looks for `if` and `match` (even ones that have 1 or fewer reachable branches). That pass is double-checked by a MIR pass that looks for `SwitchInt`s and `FakeRead`s for match scrutinees. In my opinion, there's no need to look for `Downcast` as well.

r? @oli-obk

Bump pulldown-cmark

Pulls in 0.7.1 with the following fixes:

- Update html5ever to 0.25
- Fix hang on unclosed html element

Closes #70871

MIR dump: print pointers consistently with Miri output

This makes MIR allocation dump pointer printing consistent with Miri output: both use hexadecimal offsets with a `0x` prefix. To save some space, MIR dump replaces the `alloc` prefix by `a` when necessary.

I also made AllocId/Pointer printing more consistent in their Debug/Display handling, and adjusted Display printing for Scalar a bit to avoid using decimal printing when we do not know the sign with which to interpret the value (IMO using decimal then is misleading).

Handle build completion message from Cargo

This was introduced in the recent bump to 1.44 bootstrap cargo

Fixes #71561.

Add a convenience method on `TyCtxt` for checking for thread locals

This PR extracts the cleanup part of #71192

r? @bjorn3

Vec drop and truncate: drop using raw slice *mut [T]

By creating a *mut [T] directly (without going through &mut [T]), avoid
questions of validity of the contents of the slice.

Consider the following risky code:

```rust
unsafe {
    let mut v = Vec::<bool>::with_capacity(16);
    v.set_len(16);
}
```

The intention is that with this change, we avoid one of the soundness
questions about the above snippet, because Vec::drop no longer
produces a mutable slice of the vector's contents.

r? @RalfJung

Diff:

- Don't look for old RUSTC_DEBUGINFO vars (rust-lang/backtrace-rs#313)

Rollup of 5 pull requests

Successful merges:

 - #70950 (extend NLL checker to understand `'empty` combined with universes)
 - #71433 (Add help message for missing right operand in condition)
 - #71449 (Move `{Free,}RegionRelations` and `FreeRegionMap` to `rustc_infer`)
 - #71559 (Detect git version before attempting to use --progress)
 - #71597 (Rename Unique::empty() -> Unique::dangling())

Failed merges:

r? @ghost

Rename Unique::empty() -> Unique::dangling()

A `FIXME` comment in `src/libcore/ptr/unique.rs` suggested refactoring `Unique::empty()` to `Unique::dangling()` which this PR does.

Detect git version before attempting to use --progress

Otherwise each update is run twice and errors are printed

I've tested this with:
git version 2.8.2.windows.1 (Windows)
git version 2.26.2.266.ge870325ee8 (Linux built from source)
git version 2.17.1 (Linux)
git version 2.21.1 (Apple Git-122.3) (MacOS)

I've tested with Python 2.7 (Windows, Linux, MacOS), 3.6 (Linux), and 3.7 (MacOS)

Move `{Free,}RegionRelations` and `FreeRegionMap` to `rustc_infer`

...and out of `rustc_middle`. This is to further #65031, albeit in a very minor way

r? @Mark-Simulacrum

Add help message for missing right operand in condition

closes #30035

extend NLL checker to understand `'empty` combined with universes

This PR extends the NLL region checker to understand `'empty` combined with universes. In particular, it means that the NLL region checker no longer considers `exists<R2> { forall<R1> { R1: R2 } }` to be provable. This is work towards https://github.com/rust-lang/rust/issues/59490, but we're not all the way there. One thing in particular it does not address is error messages.

The modifications to the NLL region inference code turned out to be simpler than expected. The main change is to require that if `R1: R2` then `universe(R1) <= universe(R2)`.

This constraint follows from the region lattice (shown below), because we assume then that `R2` is "at least" `empty(Universe(R2))`, and hence if `R1: R2` (i.e., `R1 >= R2` on the lattice) then `R1` must be in some universe that can name `'empty(Universe(R2))`, which requires that `Universe(R1) <= Universe(R2)`.

```
static ----------+-----...------+       (greatest)
|                |              |
early-bound and  |              |
free regions     |              |
|                |              |
scope regions    |              |
|                |              |
empty(root)   placeholder(U1)   |
|            /                  |
|           /         placeholder(Un)
empty(U1) --         /
|                   /
...                /
|                 /
empty(Un) --------                      (smallest)
```

I also made what turned out to be a somewhat unrelated change to add a special region to represent `'empty(U0)`, which we use (somewhat hackily) to indicate well-formedness checks in some parts of the compiler. This fixes #68550.

I did some investigation into fixing the error message situation. That's a bit trickier: the existing "nice region error" code around placeholders relies on having better error tracing than NLL currently provides, so that it knows (e.g.) that the constraint arose from applying a trait impl and things like that. I feel like I was hoping *not* to do such fine-grained tracing in NLL, and it seems like we...largely...got away with that. I'm not sure yet if we'll have to add more tracing information or if there is some sort of alternative.

It's worth pointing out though that I've not kind of shifted my opinion on whose job it should be to enforce lifetimes: I tend to think we ought to be moving back towards *something like* the leak-check (just not the one we *had*). If we took that approach, it would actually resolve this aspect of the error message problem, because we would be resolving 'higher-ranked errors' in the trait solver itself, and hence we wouldn't have to thread as much causal information back to the region checker. I think it would also help us with removing the leak check while not breaking some of the existing crates out there.

Regardless, I think it's worth landing this change, because it was relatively simple and it aligns the set of programs that NLL accepts with those that are accepted by the main region checker, and hence should at least *help* us in migration (though I guess we still also have to resolve the existing crates that rely on leak check for coherence).

r? @matthewjasper

ci: use bash when executing the "bors build finished" jobs

We don't clone the repository in those builders, so the default shell (`src/ci/exec-with-shell.py`) is not present there. This fixes a GHA regression introduced in #71434.

r? @Mark-Simulacrum

Rollup of 5 pull requests

Successful merges:

 - #71205 (rustc: fix check_attr() for methods, closures and foreign functions)
 - #71540 (Suggest deref when coercing `ty::Ref` to `ty::RawPtr`)
 - #71655 (Miri: better document and fix dynamic const pattern soundness checks)
 - #71672 (document missing stable counterparts of intrinsics)
 - #71692 (Add clarification on std::cfg macro docs v. #[cfg] attribute)

Failed merges:

r? @ghost

Add clarification on std::cfg macro docs v. #[cfg] attribute

The wording was discussed, to a limited degree in #71679.  This tries to
address some confusion I as well as someone else had independently when
looking at this macro.

Fixes #71679

document missing stable counterparts of intrinsics

Notes the stable counterpart of each intrinsic in case one exists.

Implements #34338

r? @Dylan-DPC

Miri: better document and fix dynamic const pattern soundness checks

https://github.com/rust-lang/const-eval/issues/42 got me thinking about soundness for consts being used in patterns, and I found a hole in our existing dynamic checks: a const referring to a mutable static *in a different crate* was not caught. This PR fixes that. It also adds some comments that explain which invariants are crucial for soundness of const-patterns.

Curiously, trying to weaponize this soundness hole failed: pattern matching compilation ICEd when encountering the cross-crate static, saying "expected allocation ID alloc0 to point to memory". I don't know why that would happen, statics *should* be entirely normal memory for pattern matching to access.

r? @oli-obk
Cc @rust-lang/wg-const-eval

Suggest deref when coercing `ty::Ref` to `ty::RawPtr`

Fixes #32122

Currently we do autoderef when casting `ty::Ref` ->`ty::Ref`, but we don't autoderef when casting `ty::Ref` -> `ty::RawPtr`. This PR make the compiler suggests deref when coercing `ty::Ref` to `ty::RawPtr`

rustc: fix check_attr() for methods, closures and foreign functions

This fixes an issue that previously turned up for methods in https://github.com/rust-lang/rust/pull/69274, but also exists for closures and foreign function: `check_attr` does not call `codegen_fn_attrs()` for these types when it should, meaning that incorrectly used function attributes are not diagnosed without codegen.

The issue affects our UI tests, as they run with `--emit=metadata` by default, but as it turns out, this is not the only case: Function attributes are not checked on any dead code without this fix!

This makes the fix a **breaking change**. The following very silly Rust programs compiles fine on stable Rust when it should not, which is fixed by this PR.
```rust
fn main() {
    #[target_feature(enable = "sse2")]
    || {};
}
```

I assume any real-world program which may trigger this issue would at least emit a dead code warning, but of course that is no guarantee that such code does not exist...

Fixes #70307

rename-unique: Change calls and doc in raw_vec.rs

rename-unique: Change empty() -> dangling() in const-ptr-unique-rpass.rs

Remove -Z no-landing-pads flag

Since #67502, `-Z no-landing-pads` will cause all attempted unwinds to abort since we don't generate a `try` / `catch`. This previously worked because `__rust_try` was located in libpanic_unwind which is always compiled with `-C panic=unwind`, but `__rust_try` is now directly inline into the crate that uses `catch_unwind`.

As such, `-Z no-landing-pads` is now mostly useless and people should use `-C panic=abort` instead.

update Miri

Fixes https://github.com/rust-lang/rust/issues/71632
r? @ghost
Cc @rust-lang/miri