Enable ThinLTO with incremental compilation.
This is an updated version of #52309. This PR allows `rustc` to use (local) ThinLTO and incremental compilation at the same time. In theory this should allow for getting compile-time improvements for small changes while keeping the runtime performance of the generated code roughly the same as when compiling non-incrementally.
The difference to #52309 is that this version also caches the pre-LTO version of LLVM bitcode. This allows for another layer of caching:
1. if the module itself has changed, we have to re-codegen and re-optimize.
2. if the module itself has not changed, but a module it imported from during ThinLTO has, we don't need to re-codegen and don't need to re-run the first optimization phase. Only the second (i.e. ThinLTO-) optimization phase is re-run.
3. if neither the module itself nor any of its imports have changed then we can re-use the final, post-ThinLTO version of the module. (We might have to load its pre-ThinLTO version though so it's available for other modules to import from)
Various small diagnostic and code clean up
- Point at def span on incorrect `panic` or `oom` function
- Use structured suggestion instead of note for `+=` that can be performed on a dereference of the left binding
- Small code formatting cleanup
refactor match guard
This is the first step to implement RFC 2294: if-let-guard. Tracking issue: https://github.com/rust-lang/rust/issues/51114
The second step should be introducing another variant `IfLet` in the Guard enum. I separated them into 2 PRs for the convenience of reviewers.
r? @petrochenkov
Implement the `min_const_fn` feature gate
cc @RalfJung @eddyb
r? @Centril
implements the feature gate for #53555
I added a hack so the `const_fn` feature gate also enables the `min_const_fn` feature gate. This ensures that nightly users of `const_fn` don't have to touch their code at all.
The `min_const_fn` checks are run first, and if they succeeded, the `const_fn` checks are run additionally to ensure we didn't miss anything.
Fix promotion stability hole in old borrowck
r? @nikomatsakis
I screwed up the promotion stability checks. Big time. They were basically nonexistant. We had tests for it. I also screwed up said tests. This is in stable already :(
Basically stability checks of promotion only worked if you tried to use a const fn defined in the same crate.
cc @eddyb
Rollup of 20 pull requests
Successful merges:
- #51760 (Add another PartialEq example)
- #53113 (Add example for Cow)
- #53129 (remove `let x = baz` which was obscuring the real error)
- #53389 (document effect of join on memory ordering)
- #53472 (Use FxHash{Map,Set} instead of the default Hash{Map,Set} everywhere in rustc.)
- #53476 (Add partialeq implementation for TryFromIntError type)
- #53513 (Force-inline `shallow_resolve` at its hottest call site.)
- #53655 (set applicability)
- #53702 (Fix stabilisation version for macro_vis_matcher.)
- #53727 (Do not suggest dereferencing in macro)
- #53732 (save-analysis: Differentiate foreign functions and statics.)
- #53740 (add llvm-readobj to llvm-tools-preview)
- #53743 (fix a typo: taget_env -> target_env)
- #53747 (Rustdoc fixes)
- #53753 (expand keep-stage --help text)
- #53756 (Fix typo in comment)
- #53768 (move file-extension based .gitignore down to src/)
- #53785 (Fix a comment in src/libcore/slice/mod.rs)
- #53786 (Replace usages of 'bad_style' with 'nonstandard_style'.)
- #53806 (Fix UI issues on Implementations on Foreign types)
Failed merges:
r? @ghost
Miri refactor: Final round
Tying up some loose ends that I noticed in the previous PRs -- and finally getting argument passing into a shape where @eddyb says it is "okay", which is a big improvement over the previous verdict that I cannot quote in public. ;)
Also move a bunch of useful helpers to construct `Scalar` from miri to here.
Cc @eddyb
r? @oli-obk
Use FxHash{Map,Set} instead of the default Hash{Map,Set} everywhere in rustc.
Most of the compiler uses the `Fx` hasher but some places ended up with the default one.
