…call, r=ecstatic-morse

Allow calling `get_body_with_borrowck_facts` without `-Z polonius`

For my [static analysis tool](https://github.com/willcrichton/flowistry), I need to access the set of outlives-constraints. Recently, rust-lang#86977 merged a way to access these facts via Polonius. However, the merged implementation requires `-Z polonius` to be provided to use this feature. This uses Polonius for borrow checking on the entire crate, which as described [here](https://rust-lang.zulipchat.com/#narrow/stream/186049-t-compiler.2Fwg-polonius/topic/Polonius.20performance.20in.20a.20rustc.20plugin/near/251301631), is very slow.

This PR allows `get_body_with_borrowck_facts` to be called without `-Z polonius`. This is essential for my tool to run in a sensible length of time. This is a temporary patch as the Polonius-related APIs develop -- I can update my code as future changes happen.

Additionally, this PR also makes public two APIs that were previously public but then became private after `rustc_mir` got broken up: `rustc_mir_dataflow::framework::graphviz` and `rustc_mir_transform::MirPass`. I need both of these for my analysis tool. (I can break this change into a separate PR if necessary.)

…call, r=ecstatic-morse

Allow calling `get_body_with_borrowck_facts` without `-Z polonius`

For my [static analysis tool](https://github.com/willcrichton/flowistry), I need to access the set of outlives-constraints. Recently, rust-lang#86977 merged a way to access these facts via Polonius. However, the merged implementation requires `-Z polonius` to be provided to use this feature. This uses Polonius for borrow checking on the entire crate, which as described [here](https://rust-lang.zulipchat.com/#narrow/stream/186049-t-compiler.2Fwg-polonius/topic/Polonius.20performance.20in.20a.20rustc.20plugin/near/251301631), is very slow.

This PR allows `get_body_with_borrowck_facts` to be called without `-Z polonius`. This is essential for my tool to run in a sensible length of time. This is a temporary patch as the Polonius-related APIs develop -- I can update my code as future changes happen.

Additionally, this PR also makes public two APIs that were previously public but then became private after `rustc_mir` got broken up: `rustc_mir_dataflow::framework::graphviz` and `rustc_mir_transform::MirPass`. I need both of these for my analysis tool. (I can break this change into a separate PR if necessary.)

…arth

Rollup of 10 pull requests

Successful merges:

 - rust-lang#88292 (Enable --generate-link-to-definition for rustc's docs)
 - rust-lang#88729 (Recover from `Foo(a: 1, b: 2)`)
 - rust-lang#88875 (cleanup(rustc_trait_selection): remove vestigial code from rustc_on_unimplemented)
 - rust-lang#88892 (Move object safety suggestions to the end of the error)
 - rust-lang#88928 (Document the closure arguments for `reduce`.)
 - rust-lang#88976 (Clean up and add doc comments for CStr)
 - rust-lang#88983 (Allow calling `get_body_with_borrowck_facts` without `-Z polonius`)
 - rust-lang#88985 (Update clobber_abi list to include k[1-7] regs)
 - rust-lang#88986 (Update the backtrace crate)
 - rust-lang#89009 (Fix typo in `break` docs)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

…facts-flag, r=ecstatic-morse

Populate liveness facts when calling `get_body_with_borrowck_facts` without `-Z polonius`

For a new feature of [Flowistry](https://github.com/willcrichton/flowistry), a static-analysis tool, we need to obtain a `mir::Body`'s liveness facts using `get_body_with_borrowck_facts` (added in rust-lang#86977). We'd like to do this without passing `-Z polonius` as a compiler arg to avoid borrow checking the entire crate.

Support for doing this was added in rust-lang#88983, but the Polonius input facts used for liveness analysis are empty. This happens because the liveness input facts are populated in `liveness::generate` depending only on the value of `AllFacts::enabled` (which is toggled via compiler args).

This PR propagates the [`use_polonius`](https://github.com/rust-lang/rust/blob/8b09ba6a5d5c644fe0f1c27c7f9c80b334241707/compiler/rustc_borrowck/src/nll.rs#L168) flag to `liveness::generate` to support populating liveness facts without requiring the `-Z polonius` flag.

This fix is somewhat patchy - if it'd be better to add more widely-accessible state (like `AllFacts::enabled`) I'd be open to ideas!

…facts-flag, r=ecstatic-morse

Populate liveness facts when calling `get_body_with_borrowck_facts` without `-Z polonius`

For a new feature of [Flowistry](https://github.com/willcrichton/flowistry), a static-analysis tool, we need to obtain a `mir::Body`'s liveness facts using `get_body_with_borrowck_facts` (added in rust-lang#86977). We'd like to do this without passing `-Z polonius` as a compiler arg to avoid borrow checking the entire crate.

Support for doing this was added in rust-lang#88983, but the Polonius input facts used for liveness analysis are empty. This happens because the liveness input facts are populated in `liveness::generate` depending only on the value of `AllFacts::enabled` (which is toggled via compiler args).

This PR propagates the [`use_polonius`](https://github.com/rust-lang/rust/blob/8b09ba6a5d5c644fe0f1c27c7f9c80b334241707/compiler/rustc_borrowck/src/nll.rs#L168) flag to `liveness::generate` to support populating liveness facts without requiring the `-Z polonius` flag.

This fix is somewhat patchy - if it'd be better to add more widely-accessible state (like `AllFacts::enabled`) I'd be open to ideas!