When an import like `use crate::a::b::Item` fails because module `b` is
private, the resolver now looks up public re-export paths for `Item` and
suggests them to the user.

…le errors

Previously this was not correctly implemented. Each funclet may need its own terminate
block, so this changes the `terminate_block` into a `terminate_blocks` `IndexVec` which
can have a terminate_block for each funclet. We key on the first basic block of the
funclet -- in particular, this is the start block for the old case of the top level
terminate function.

Rather than using a catchswitch/catchpad pair, I used a cleanuppad. The reason for the
pair is to avoid catching foreign exceptions on MSVC. On wasm, it seems that the
catchswitch/catchpad pair is optimized back into a single cleanuppad and a catch_all
instruction is emitted which will catch foreign exceptions. Because the new logic is
only used on wasm, it seemed better to take the simpler approach seeing as they do the
same thing.

As the FIXME comment says, these no longer use `ParseSess` and so the
`parse` mod is not a good place for them. The `errors` mod is a better
home.

Various places where `lift` just isn't necessary. Either because we're
not within a closure passed to `tls::with`, or because the type being lifted
doesn't have a `'tcx` lifetime.

Every lifting root calls `unwrap`/`expect` on the result, except for
`ImmTy::fmt` but there's no good reason for that exception. Making
lifting infallible is sensible because it should only fail if the wrong
interner is somehow used, which indicates a major bug in rustc rather
than an error condition.

Android targets must not inherit `target_env="gnu"` from the Linux GNU
base. Cover this in the existing print-cfg run-make test so a future
target-spec refactor cannot silently re-introduce it.

…from queries

fatal errors currently abort the compiler process without allocating the self-profile
strings: query events aren't always correctly recorded, and will show up as <unknown>
in the data.

catching the unwinding panic allows us to finalize the self-profiling process correctly
before continuing unwinding as before.

This is necessary to fix incremental LTO in cg_gcc as well as to do some
LTO refactorings I want to do. The actual fix for cg_gcc will be done on
the cg_gcc repo to test it in CI.

…and, r=bjorn3

Fix: On wasm targets, call `panic_in_cleanup` if panic occurs in cleanup

Relies on rust-lang/llvm-project#194.
Reland of rust-lang#151771.

Previously this was not correctly implemented. Each funclet may need its own terminate block, so this changes the `terminate_block` into a `terminate_blocks` `IndexVec` which can have a terminate_block for each funclet. We key on the first basic block of the funclet -- in particular, this is the start block for the old case of the top level terminate function.

Rather than using a catchswitch/catchpad pair, I used a cleanuppad. The reason for the pair is to avoid catching foreign exceptions on MSVC. On wasm, it seems that the catchswitch/catchpad pair is optimized back into a single cleanuppad and a catch_all instruction is emitted which will catch foreign exceptions. Because the new logic is only used on wasm, it seemed better to take the simpler approach seeing as they do the same thing.

- [ ] Add test for rust-lang#153948

Use `_mcount` as the mcount symbol name on RISC-V Linux GNU targets

Fixes rust-lang#155830

glibc on RISC-V exports `_mcount`, not `mcount`. https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/riscv/machine-gmon.h;hb=HEAD

r? mati865 (I think you're well-suited to review this area, but feel free to reroll)

simplify `ast_fragments!`

The syntax and meaning of this macro are not very intuitive as its just a large dump of function names and has some special cases.
Each commit should be a small improvement that can be evaluated on its own.

…r=nikomatsakis

Add feature gate for view_types experiment

…-arch, r=joshtriplett

add `c_variadic_experimental_arch` feature

tracking issue: rust-lang#155973

Based on https://hackmd.io/pIbUgMQuQcGaibJcinOcEw#Stabilize-c-variadic-function-definitions-rust155697, we'll gate niche targets where we don't control the implementation of `va_arg`, the ABI is unclear, or in general where we're not confident stabilizing the implementation.

…jorn3

Catch unwinds from the global ctxt callback to complete queries profiling data in more cases

The driver/compiler interface provides multiple callbacks, and we sometimes catch unwinds to flush diagnostics, ensure ICEs appear, and so on even when fatal errors occur.

When these panics happen, we don't `finish` the `TyCtxt`, and there's a fixme about that. Unfortunately this is where we also allocate the self-profile strings: query events for example start as virtual and are turned into real strings by this finalization process; they are _invalid_ without this step. When fatal errors happen, the in-flight query name will be `<unknown>`, event counts will be inaccurate, etc.

This PR catches panics from another of these callbacks, where the `TyCtxt` is available, to allow for the self-profiling data to be computed before continuing the unwinding process as before. `finish` does more things, that I don't want to introduce here.

I remember seeing this discussed in GH issues in the past, but can't find any open ones now. It may also have been only mentioned while trying to profile existing slowness issues. I stumbled upon this again recently when looking into `tests/ui/try-trait/deep-try-chain-issue-153583.rs`, where the slowest query is `<unknown>`.

```
> rm *.mm_profdata ; rustc +nightly -Zself-profile tests/ui/try-trait/deep-try-chain-issue-153583.rs ; summarize summarize *.mm_profdata | head -n 5

error[E0277]: the `?` operator can only be applied to values that implement `Try`
 --> tests/ui/try-trait/deep-try-chain-issue-153583.rs:6:5
  |
6 |     0?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????...
  |     ^^ the `?` operator cannot be applied to type `{integer}`
  |
  = help: the nightly-only, unstable trait `Try` is not implemented for `{integer}`

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0277`.
+------------------------------------------------------+-----------+-----------------+----------+------------+
| Item                                                 | Self time | % of total time | Time     | Item count |
+------------------------------------------------------+-----------+-----------------+----------+------------+
| <unknown>                                            | 1.55s     | 99.416          | 3.21s    | 15230      |
+------------------------------------------------------+-----------+-----------------+----------+------------+
```

This PR fixes that case at least. In general, it should fix the invalid profiling records for fatal errors happening while a query is running.

```
+------------------------------------------------------+-----------+-----------------+----------+------------+
| Item                                                 | Self time | % of total time | Time     | Item count |
+------------------------------------------------------+-----------+-----------------+----------+------------+
| typeck_root                                          | 5.04s     | 95.588          | 5.08s    | 1          |
+------------------------------------------------------+-----------+-----------------+----------+------------+
```

r? @bjorn3

Pass Session to optimize_and_codegen_fat_lto

This is necessary to fix incremental LTO in cg_gcc as well as to do some LTO refactorings I want to do. The actual fix for cg_gcc will be done on the cg_gcc repo to test it in CI.

Suggest public re-exports when a private module makes an import path inaccessible

This is an attempt at solving rust-lang#13065.

When a `use` path fails because it passes through a private module (E0603), and a public re-export of the target item exists elsewhere, the compiler will now suggest importing through that re-export instead.

For example, given:

```rust
mod outer {
    pub use self::inner::MyStruct;
    mod inner {
        pub struct MyStruct;
    }
}

use outer::inner::MyStruct; // error: module `inner` is private
```

the compiler will now suggest use `outer::MyStruct`; - the publicly accessible path - rather than just pointing at the private module definition and leaving the user to figure out the alternative.

When possible, relative paths are suggested, including those using `super` (currently capped at a maximum of one `super` path item).

The newly added test is parametrised by editions because of the change in behaviour around `crate::`-prefixed imports in edition 2018. Perhaps that’s an overkill – I’ll be happy to remove the variations for editions 2021 and 2024.

Closes rust-lang#13065.

…02, r=Kivooeo

Reorganize `tests/ui/issues/` - 02

| old-name | new-sub-dir | new-name |
|-|-|-|
| `issue-19001.rs` [issue](rust-lang#19001) | `recursion/` | `recursive-struct-with-raw-pointer-field.rs` |
| `issue-31769.rs` [issue](rust-lang#31769) | `attributes/` | `dont-allow-inline-and-repr-at-invalid-positions.rs` |
| `issue-31769.stderr` | `attributes/` | `dont-allow-inline-and-repr-at-invalid-positions.stderr` |
| `issue-33202.rs` [issue](rust-lang#33202) | `attributes/` | `repr-on-single-variant-Enum.rs` |
| `issue-38763.rs` [issue](rust-lang#38763) | `foreign/` | `foreign-fn-with-more-than-8-byte-arg-size.rs` |

r? Kivooeo

…TaKO8Ki

Move `feature*` methods from `parse` mod to `errors` mod.

As the FIXME comment says, these no longer use `ParseSess` and so the `parse` mod is not a good place for them. The `errors` mod is a better home.

r? @TaKO8Ki

…oli-obk

Make lifting infallible

Details in individual commits.

r? @oli-obk

…env-print-cfg, r=petrochenkov

tests/run-make/print-cfg: add Android target_env case

Regression test for rust-lang#90834

rust-lang#77729 + rust-lang#78929 accidentally gave Android targets `target_env="gnu"`
through `android_base` inheriting from `linux_gnu_base`. rust-lang#90834 moved it
back to plain `linux_base` but didn't add a test, so a future target-spec
refactor could bring it back unnoticed. This adds an Android case to
`tests/run-make/print-cfg` covering exactly that.

r? @petrochenkov