There is no safety contract and I don't think any of them can actually
cause UB in more ways than passing malicious source code to rustc can.
While LtoModuleCodegen::optimize says that the returned ModuleCodegen
points into the LTO module, the LTO module has already been dropped by
the time this function returns, so if the returned ModuleCodegen indeed
points into the LTO module, we would have seen crashes on every LTO
compilation, which we don't. As such the comment is outdated.
Rename `is_like_osx` to `is_like_darwin`
Replace `is_like_osx` with `is_like_darwin`, which more closely describes reality (OS X is the pre-2016 name for macOS, and is by now quite outdated; Darwin is the overall name for the OS underlying Apple's macOS, iOS, etc.).
``@rustbot`` label O-apple
r? compiler
Avoid no-op unlink+link dances in incr comp
Incremental compilation scales quite poorly with the number of CGUs. This PR improves one reason for that.
The incr comp process hard-links all the files from an old session into a new one, then it runs the backend, which may just hard-link the new session files into the output directory. Then codegen hard-links all the output files back to the new session directory.
This PR (perhaps unimaginatively) fixes the silliness that ensues in the last step. The old `link_or_copy` implementation would be passed pairs of paths which are already the same inode, then it would blindly delete the destination and re-create the hard-link that it just deleted. This PR lets us skip both those operations. We don't skip the other two hard-links.
`cargo +stage1 b && touch crates/core/main.rs && strace -cfw -elink,linkat,unlink,unlinkat cargo +stage1 b` before and then after on `ripgrep-13.0.0`:
```
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
52.56 0.024950 25 978 485 unlink
34.38 0.016318 22 727 linkat
13.06 0.006200 24 249 unlinkat
------ ----------- ----------- --------- --------- ----------------
100.00 0.047467 24 1954 485 total
```
```
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
42.83 0.014521 57 252 unlink
38.41 0.013021 26 486 linkat
18.77 0.006362 25 249 unlinkat
------ ----------- ----------- --------- --------- ----------------
100.00 0.033904 34 987 total
```
This reduces the number of hard-links that are causing perf troubles, noted in https://github.com/rust-lang/rust/issues/64291 and https://github.com/rust-lang/rust/issues/137560
Continuing the work from #137350.
Removes the unused methods: `expect_variant`, `expect_field`,
`expect_foreign_item`.
Every method gains a `hir_` prefix.
Clean up various LLVM FFI things in codegen_llvm
cc ```@ZuseZ4``` I touched some autodiff parts
The major change of this PR is [bfd88ce](bfd88cead0) which makes `CodegenCx` generic just like `GenericBuilder`
The other commits mostly took advantage of the new feature of making extern functions safe, but also just used some wrappers that were already there and shrunk unsafe blocks.
best reviewed commit-by-commit
The embedded bitcode should always be prepared for LTO/ThinLTO
Fixes#115344. Fixes#117220.
There are currently two methods for generating bitcode that used for LTO. One method involves using `-C linker-plugin-lto` to emit object files as bitcode, which is the typical setting used by cargo. The other method is through `-C embed-bitcode=yes`.
When using with `-C embed-bitcode=yes -C lto=no`, we run a complete non-LTO LLVM pipeline to obtain bitcode, then the bitcode is used for LTO. We run the Call Graph Profile Pass twice on the same module.
This PR is doing something similar to LLVM's `buildFatLTODefaultPipeline`, obtaining the bitcode for embedding after running `buildThinLTOPreLinkDefaultPipeline`.
r? nikic
Misc. `rustc_codegen_ssa` cleanups 🧹
Just a bunch of stuff I found while reading the crate's code.
Each commit can stand on its own.
Maybe r? `@Noratrieb` because I saw you did some similar cleanups on these files a while ago? (feel free to re-assign, I'm just guessing)
`rustc_span::symbol` defines some things that are re-exported from
`rustc_span`, such as `Symbol` and `sym`. But it doesn't re-export some
closely related things such as `Ident` and `kw`. So you can do `use
rustc_span::{Symbol, sym}` but you have to do `use
rustc_span::symbol::{Ident, kw}`, which is inconsistent for no good
reason.
This commit re-exports `Ident`, `kw`, and `MacroRulesNormalizedIdent`,
and changes many `rustc_span::symbol::` qualifiers in `compiler/` to
`rustc_span::`. This is a 200+ net line of code reduction, mostly
because many files with two `use rustc_span` items can be reduced to
one.
Pass end position of span through inline ASM cookie
Before this PR, only the start position of the span was passed though the inline ASM cookie to diagnostics. LLVM 19 has full support for 64-bit inline ASM cookies; this PR uses that to pass the end position of the span in the upper 32 bits, meaning inline ASM diagnostics now point at the entire line the error occurred on, not just the first character of it.
The target name can be anything with custom target specs. Matching on
fields inside the target spec is much more robust than matching on the
target name.
Create `_imp__` symbols also when doing ThinLTO
When generating a rlib crate on Windows we create `dllimport` / `_imp__` symbols for each global. This effectively makes the rlib contain an import library for itself and allows them to both be dynamically and statically linked. However when doing ThinLTO we do not generate these and thus we end up with missing symbols. Microsoft's `link` can fix these up (and emits warnings), but `lld` seems to currently be unable to.
This PR also does this generation for ThinLTO avoiding those issues with `lld` and also avoids the warnings on `link`.
This is an workaround for https://github.com/rust-lang/rust/issues/81408.
cc `@lqd`
Implement a Method to Seal `DiagInner`'s Suggestions
This PR adds a method on `DiagInner` called `.seal_suggestions()` to prevent new suggestions from being added while preserving existing suggestions.
This is useful because currently there is no way to prevent new suggestions from being added to a diagnostic. `.disable_suggestions()` is the closest but it gets rid of all suggestions before and after the call.
Therefore, `.seal_suggestions()` can be used when, for example, misspelled keyword is detected and reported. In such cases, we may want to prevent other suggestions from being added to the diagnostic, as they would likely be meaningless once the misspelled keyword is identified. For context: https://github.com/rust-lang/rust/pull/129899#discussion_r1741307132
To store an additional state, the type of the `suggestions` field in `DiagInner` was changed into a three variant enum. While this change affects files across different crates, care was taken to preserve the existing code's semantics. This is validated by the fact that all UI tests pass without any modifications.
r? chenyukang
Deprecate no-op codegen option `-Cinline-threshold=...`
This deprecates `-Cinline-threshold` since using it has no effect. This has been the case since the new LLVM pass manager started being used, more than 2 years ago.
Recommend using `-Cllvm-args=--inline-threshold=...` instead.
Closes#89742 which is E-help-wanted.
