uniquify root goals during HIR typeck
We need to rely on region identity to deal with hangs such as https://github.com/rust-lang/trait-system-refactor-initiative/issues/210 and to keep the current behavior of `fn try_merge_responses`.
This is a problem as borrowck starts by replacing each *occurrence* of a region with a unique inference variable. This frequently splits a single region during HIR typeck into multiple distinct regions. As we assume goals to always succeed during borrowck, relying on two occurances of a region being identical during HIR typeck causes ICE. See the now fixed examples in https://github.com/rust-lang/trait-system-refactor-initiative/issues/27 and rust-lang/rust#139409.
We've previously tried to avoid this issue by always *uniquifying* regions when canonicalizing goals. This prevents caching subtrees during canonicalization which resulted in hangs for very large types. People rely on such types in practice, which caused us to revert our attempt to reinstate `#[type_length_limit]` in https://github.com/rust-lang/rust/pull/127670. The complete list of changes here:
- rust-lang/rust#107981
- rust-lang/rust#110180
- rust-lang/rust#114117
- rust-lang/rust#130821
After more consideration, all occurrences of such large types need to happen outside of typeck/borrowck. We know this as we already walk over all types in the MIR body when replacing their regions with nll vars.
This PR therefore enables us to rely on region identity inside of the trait solver by exclusively **uniquifying root goals during HIR typeck**. These are the only goals we assume to hold during borrowck. This is insufficient as type inference variables may "hide" regions we later uniquify. Because of this, we now stash proven goals which depend on inference variables in HIR typeck and reprove them after writeback. This closes https://github.com/rust-lang/trait-system-refactor-initiative/issues/127.
This was originally part of rust-lang/rust#144258 but I've moved it into a separate PR. While I believe we need to rely on region identity to fix the performance issues in some way, I don't know whether rust-lang/rust#144258 is the best approach to actually do so. Regardless of how we deal with the hangs however, this change is necessary and desirable regardless.
r? `@compiler-errors` or `@BoxyUwU`
Remove eval_always from check_private_in_public.
This PR attempts to avoid re-computing `check_private_in_public` query. First by marking the query as non-`eval_always`, and by reducing the amount of accesses to HIR as much as possible.
Latest perf https://github.com/rust-lang/rust/pull/116316#issuecomment-3094672105 shows that we manage it. The cost is extra dep-graph bookkeeping.
Reject running `compiletest` self-tests against stage 0 rustc unless explicitly allowed
Currently, in `pr-check-1`, we run `python3 ../x.py test --stage 0 src/tools/compiletest`, which is `compiletest` self-tests against stage 0 rustc. This makes it very annoying for PRs wanting to change target spec JSON format, which `compiletest` depends on for target information, as otherwise `compiletest` would have to know how to handle 2 different target spec JSON formats and know when to pick which.
Instead of doing that, we change `compiletest` self-tests to reject running against stage 0 `rustc` *unless* explicitly allowed with `build.compiletest-allow-stage0=true`. `build.compiletest-allow-stage0` is a proper bootstrap config option in favor of the ad-hoc `COMPILETEST_FORCE_STAGE0` env var. This means that:
- `./x test src/tools/compiletest --stage=0` is not allowed, unless `build.compiletest-allow-stage0=true` is set. In this scenario, `compiletest` self-tests should be expected to fail unless the stage 0 `rustc` as provided is like codegen_cranelift where it's *actually* built from in-tree `rustc` sources.
- In CI, we change `./x test src/tools/compiletest --stage=0` to `./x test src/tools/compiletest --stage=1`, and move it to `pr-check-2`. Yes, this involves building the stage 1 compiler, but `pr-check-2` already has to build stage 1 compiler to test stage 1 library crates.
- Crucially, this means that **`compiletest` is only intended to support one target spec JSON format**, namely the one corresponding to the in-tree `rustc`.
- This should preserve the `compiletest-use-stage0-libtest` UX optimization where changing `compiler/` tree should still not require rebuilding `compiletest` as long as `build.compiletest-use-stage0-libtest=true`, as that should remain orthogonal. This is completely unlike my previous attempt at https://github.com/rust-lang/rust/pull/144563 that tries to do a way more invasive change which would cause the rebuild problem.
Best reviewed commit-by-commit.
---
r? `@Kobzol`
clean up codegen fn attrs
This honestly had become a mess over time and needed some love. No behavior should've changed, and I effectively just moved code around. Though, I can't promise there weren't any bugs in the original code with how randomly it was organised.....
r? `@WaffleLapkin`
Support multiple crate versions in --extern-html-root-url
Rustdoc's `--extern-html-root-url` used to use `tcx.crate_name()` to identify crates, but that used crates' internal names from their metadata, instead of names given to them in `--extern`. That was confusing, because both `--extern…` arguments seem related and use similar syntax. Crucially, this didn't work correctly with Cargo's package aliases or multiple versions of crates.
`sess.opts.externs` lacks `CrateNum`, and `Resolver.extern_prelude` gets destroyed before `rustdoc` has a chance to see it, so I've had to save this mapping in `CStore`.
Just in case, I've kept the previous mapping by crate name as a fallback for crates that weren't matched by their extern name.
Fixesrust-lang/rust#76296
Otherwise, `compiletest` would have to know e.g. how to parse two
different target spec, if target spec format was changed between beta
`rustc` and in-tree `rustc`.
Rollup of 6 pull requests
Successful merges:
- rust-lang/rust#144042 (Verify llvm-needs-components are not empty and match the --target value)
- rust-lang/rust#144268 (Add method `find_ancestor_not_from_macro` and `find_ancestor_not_from_extern_macro` to supersede `find_oldest_ancestor_in_same_ctxt`)
- rust-lang/rust#144411 (Remove `hello_world` directory)
- rust-lang/rust#144662 (compiletest: Move directive names back into a separate file)
- rust-lang/rust#144666 (Make sure to account for the right item universal regions in borrowck)
- rust-lang/rust#144668 ([test][run-make] add needs-llvm-components)
r? `@ghost`
`@rustbot` modify labels: rollup
Make sure to account for the right item universal regions in borrowck
Fixes https://github.com/rust-lang/rust/issues/144608.
The ICE comes from a mismatch between the liberated late bound regions (i.e. "`ReLateParam`"s) that come from promoting closure outlives, and the regions we have in our region vid mapping from `UniversalRegions`.
When building `UniversalRegions`, we end up using the liberated regions from the binder of the closure's signature:
c8bb4e8a12/compiler/rustc_borrowck/src/universal_regions.rs (L521)
Notably, this signature may be anonymized if the closure signature being deduced comes from an external constraints:
c8bb4e8a12/compiler/rustc_hir_typeck/src/closure.rs (L759-L762)
This is true in the test file I committed, where the signature is influenced by the `impl FnMut(&mut ())` RPIT.
However, when promoting a type outlives constraint we end up creating a late bound lifetime mapping that disagrees with those liberated late bound regions we constructed in `UniversalRegions`:
c8bb4e8a12/compiler/rustc_borrowck/src/universal_regions.rs (L299)
Specifically, in `for_each_late_bound_region_in_item` (which is called by `for_each_late_bound_region_in_recursive_scope`), we were using `tcx.late_bound_vars` which uses the late bound regions *from the HIR*. This query both undercounts the late bound regions (e.g. those that end up being deduced from bounds), and also doesn't account for the fact that we anonymize them in the signature as mentioned above.
c8bb4e8a12/compiler/rustc_borrowck/src/universal_regions.rs (L977)
This PR fixes that function to use the *correct signature*, which properly considers the bound vars that come from deducing the signature of the closure, and which comes from the closure's args from the `type_of` query.
compiletest: Move directive names back into a separate file
This list no longer needs to be included in multiple crates, but having the list in its own file makes it easier to find and update when necessary.
As discussed at https://github.com/rust-lang/rust/pull/143850#issuecomment-3130307023.
Remove `hello_world` directory
Move `tests/ui/hello_world/main.rs` and retire the single-file `tests/ui/hello_world/` directory.
Part of https://github.com/rust-lang/rust/issues/133895.
r? `@jieyouxu`
Add method `find_ancestor_not_from_macro` and `find_ancestor_not_from_extern_macro` to supersede `find_oldest_ancestor_in_same_ctxt`
As I was using it, I realized that the function is supposed to walk up to expand the chain? This seems to be the opposite of what I understood.
r? `@jieyouxu`
Verify llvm-needs-components are not empty and match the --target value
I recently discovered a test with an empty `llvm-needs-components` entry (fixed in rust-lang/rust#143979) which meant that it didn't work correctly when building Rust with a limited set of LLVM targets.
This change makes a pair of improvements to prevent this issue from creeping in again:
* When parsing directives with values, `compiletest` will now raise an error if there is an empty value.
* Improved the `target_specific_tests` tidy checker to map targets to LLVM components, to verify that any existing `llvm-needs-components` contains the target being used.
I also fixed all the issues flagged by the improved tidy checker.
Free disk space on Windows 2025 runners
I've managed to reduce the time deletion takes by:
- Using powershell, which is generally faster for filesystem operations than msys2
- Performing deletions concurrently then waiting for them all to complete
It still takes 2-10 mins but that's not too bad.
Add support for the m68k architecture in 'object_architecture'
This is a tiny PR that adds the m68k architecture to `object_architecture`. This allows us to build rmeta files for that ISA(we use the object crate to pack metadata into object files).
Update wasi-sdk to 27.0 in CI
This updates the wasi-sdk used in CI to build release binaries and run CI with. No major motivation beyond keeping things up-to-date and following the development of wasi-sdk.
Enable T-compiler backport nomination
This patches the triagebot.toml so that it will trigger a backport label on pull requests fixing regressions. Applying a backport label will trigger creating a Zulip thread. For now the configuration only for `T-compiler` labeled regressions.
Comments in the code explain how it works. Documentation [on the forge](https://forge.rust-lang.org/triagebot/backport.html).
```
[backport.foo]
# The pull request MUST have one of these labels
required_pr_labels = ["T-compiler"]
# The regression MUST have this label
required_issue_label = "regression-from-stable-to-beta"
# if the above conditions matches, the PR will receive these labels
add_labels = ["beta-nominated"]
```
Anything to think about before merging this?
thanks for a review
Fix Ord, Eq and Hash implementation of panic::Location
Fixes https://github.com/rust-lang/rust/issues/144486.
Now properly compares/hashes the filename rather than the pointer to the string.
tests: Test line number in debuginfo for diverging function calls
Closesrust-lang/rust#59558 which just [E-needs-test](https://github.com/rust-lang/rust/issues/59558#issuecomment-1322236891).
The bug seems to have been fixed in **nightly-2021-05-10**:
```sh
for toolchain in nightly-2021-05-09 \
nightly-2021-05-10 \
1.88; do
echo -e "\nWith $toolchain:"
rustc +$toolchain tests/codegen/diverging-function-call-debuginfo.rs --emit llvm-ir -o /tmp/out.ll -g -Clto -Copt-level=0
build/x86_64-unknown-linux-gnu/ci-llvm/bin/FileCheck --input-file /tmp/out.ll tests/codegen/diverging-function-call-debuginfo.rs --check-prefix=CHECK --dump-input-context 10 2>/dev/null && echo OK || echo FAIL
done
```
```
With nightly-2021-05-09:
FAIL
With nightly-2021-05-10:
OK
With 1.88:
OK
```
which gives the following list of candidate commits. Not clear which one it is exactly but it doesn't matter much since we can confirm that the test works. I have confirmed locally that with **nightly-2021-05-09** we get `line: 0` for the last call.
<details>
<summary>click to expand</summary>
```
$ git log ^881c1ac408ca82264ec7 --no-merges --oneline
```
f25aa5767f Remove unused `opt_span_warn` function
ebbc949575 Note why `Handler::fatal` is different from `Sesssion::fatal`
96509b4835 Make `Diagnostic::span_fatal` unconditionally raise an error
e49f4471aa Remove some unnecessary uses of `struct_span_fatal`
955fdaea4a Rename `Parser::span_fatal_err` -> `Parser::span_err`
4b7c8b0b53 Add `#[track_caller]` to `FakeDefId::expect_real()`
ba13225ba1 Remove `FakeDefId::expect_local()`
020d83d9f5 Enable `-W semicolon_in_expressions_from_macros` in bootstrap
1b928ff8f8 Update LLVM submodule
c2b15a6b64 Support -C passes in NewPM
5519cbfe33 Don't force -O1 with ThinLTO
7c4989ab70 Drop -opt-bisect-limit=0 flag from test
db140de8f2 Explicitly register GCOV profiling pass as well
5ecbe7fcf8 Explicitly register instrprof pass
0318883cd6 Make -Z new-llvm-pass-manager an Option<bool>
0367e24f94 Avoid predecessors having Drop impls
</details>
This updates the wasi-sdk used in CI to build release binaries and run
CI with. No major motivation beyond keeping things up-to-date and
following the development of wasi-sdk.
