The `copy` function historically in rustbuild used hard links to speed up the
copy operations that it does. This logic was backed out, however, in #39518 due
to a bug that only showed up on Windows, described in #39504. The cause
described in #39504 happened because Cargo, on a fresh build, would overwrite
the previous artifacts with new hard links that Cargo itself manages.
This behavior in Cargo was fixed in rust-lang/cargo#4390 where it no longer
should overwrite files on fresh builds, opportunistically leaving the filesystem
intact and not touching it.
Hopefully this can help speed up local builds by doing fewer copies all over the
place!
use gcc::Build rather than deprecated gcc::Config
I did `cargo update -p gcc` to upgrade only this package. Is there further process that should be follwoed when updating a build dependency from crates.io?
r? @alexcrichton
Fixes#43973
Update rls
And expose the `CFG_VERSION` env var to tools so they can determine the version of Rust.
This gets the RLS back on master and so completes the PR dance for the generators PR.
r? @alexcrichton
Initial diagnostic API for proc-macros.
This commit introduces the ability to create and emit `Diagnostic` structures from proc-macros, allowing for proc-macro authors to emit warning, error, note, and help messages just like the compiler does.
The API is somewhat based on the diagnostic API already present in `rustc` with several changes that improve usability. The entry point into the diagnostic API is a new `Diagnostic` type which is primarily created through new `error`, `warning`, `help`, and `note` methods on `Span`. The `Diagnostic` type records the diagnostic level, message, and optional `Span` for the top-level diagnostic and contains a `Vec` of all of the child diagnostics. Child diagnostics can be added through builder methods on `Diagnostic`.
A typical use of the API may look like:
```rust
let token = parse_token();
let val = parse_val();
val.span
.error(format!("expected A but found {}", val))
.span_note(token.span, "because of this token")
.help("consider using a different token")
.emit();
```
cc @jseyfried @nrc @dtolnay @alexcrichton
This commit introduces the ability to create and emit `Diagnostic`
structures from proc-macros, allowing for proc-macro authors to emit
warning, error, note, and help messages just like the compiler does.
post-rebase: Do not put "(Ast)" suffix in error msg unless passed `-Z borrowck-mir`.
(But unconditionally include "(Mir)" suffix for mir-borrowck errors.)
Cargo pulls in libc from crates.io for a number of dependencies, but
0.2.27 is too old to work properly with Solaris. In particular, it
needs the change to make Solaris' PTHREAD_PROCESS_PRIVATE a 16-bit
integer.
APFloat: Rewrite It In Rust and use it for deterministic floating-point CTFE.
As part of the CTFE initiative, we're forced to find a solution for floating-point operations.
By design, IEEE-754 does not explicitly define everything in a deterministic manner, and there is some variability between platforms, at the very least (e.g. NaN payloads).
If types are to evaluate constant expressions involving type (or in the future, const) generics, that evaluation needs to be *fully deterministic*, even across `rustc` host platforms.
That is, if `[T; T::X]` was used in a cross-compiled library, and the evaluation of `T::X` executed a floating-point operation, that operation has to be reproducible on *any other host*, only knowing `T` and the definition of the `X` associated const (as either AST or HIR).
Failure to uphold those rules allows an associated type (e.g. `<Foo as Iterator>::Item`) to be seen as two (or more) different types, depending on the current host, and such type safety violations typically allow writing of a `transmute` in safe code, given enough generics.
The options considered by @rust-lang/compiler were:
1. Ban floating-point operations in generic const-evaluation contexts
2. Emulate floating-point operations in an uniformly deterministic fashion
The former option may seem appealing at first, but floating-point operations *are allowed today*, so they can't be banned wholesale, a distinction has to be made between the code that already works, and future generic contexts. *Moreover*, every computation that succeeded *has to be cached*, otherwise the generic case can be reproduced without any generics. IMO there are too many ways it can go wrong, and a single violation can be enough for an unsoundness hole.
Not to mention we may end up really wanting floating-point operations *anyway*, in CTFE.
I went with the latter option, and seeing how LLVM *already* has a library for this exact purpose (as it needs to perform optimizations independently of host floating-point capabilities), i.e. `APFloat`, that was what I ended up basing this PR on.
But having been burned by the low reusability of bindings that link to LLVM, and because I would *rather* the floating-point operations to be wrong than not deterministic or not memory-safe (`APFloat` does far more pointer juggling than I'm comfortable with), I decided to RIIR.
This way, we have a guarantee of *no* `unsafe` code, a bit more control over the where native floating-point might accidentally be involved, and non-LLVM backends can share it.
I've also ported all the testcases over, *before* any functionality, to catch any mistakes.
Currently the PR replaces all CTFE operations to go through `apfloat::ieee::{Single,Double}`, keeping only the bits of the `f32` / `f64` memory representation in between operations.
Converting from a string also double-checks that `core::num` and `apfloat` agree on the interpretation of a floating-point number literal, in case either of them has any bugs left around.
r? @nikomatsakis
f? @nagisa @est31
<hr/>
Huge thanks to @edef1c for first demoing usable `APFloat` bindings and to @chandlerc for fielding my questions on IRC about `APFloat` peculiarities (also upstreaming some bugfixes).
Run translation and LLVM in parallel when compiling with multiple CGUs
This is still a work in progress but the bulk of the implementation is done, so I thought it would be good to get it in front of more eyes.
This PR makes the compiler start running LLVM while translation is still in progress, effectively allowing for more parallelism towards the end of the compilation pipeline. It also allows the main thread to switch between either translation or running LLVM, which allows to reduce peak memory usage since not all LLVM module have to be kept in memory until linking. This is especially good for incr. comp. but it works just as well when running with `-Ccodegen-units=N`.
In order to help tuning and debugging the work scheduler, the PR adds the `-Ztrans-time-graph` flag which spits out html files that show how work packages where scheduled:
(red is translation, green is llvm)
One side effect here is that `-Ztime-passes` might show something not quite correct because trans and LLVM are not strictly separated anymore. I plan to have some special handling there that will try to produce useful output.
One open question is how to determine whether the trans-thread should switch to intermediate LLVM processing.
TODO:
- [x] Restore `-Z time-passes` output for LLVM.
- [x] Update documentation, esp. for work package scheduling.
- [x] Tune the scheduling algorithm.
cc @alexcrichton @rust-lang/compiler
Three small fixes for save-analysis
First commit does some naive deduplication of macro uses. We end up with lots of duplication here because of the weird way we get this data (we extract a use for every span generated by a macro use).
Second commit is basically a typo fix.
Third commit is a bit interesting, it partially reverts a change from #40939 where temporary variables in format! (and thus println!) got a span with the primary pointing at the value stored into the temporary (e.g., `x` in `println!("...", x)`). If `format!` had a definition it should point at the temporary in the macro def, but since it is built-in, that is not possible (for now), so `DUMMY_SP` is the best we can do (using the span in the callee really breaks save-analysis because it thinks `x` is a definition as well as a reference).
There aren't a test for this stuff because: the deduplication is filtered by any of the users of save-analysis, so it is purely an efficiency change. I couldn't actually find an example for the second commit that we have any machinery to test, and the third commit is tested by the RLS, so there will be a test once I update the RLS version and and uncomment the previously failing tests).
r? @jseyfried
Rework Rustbuild to an eagerly compiling approach
This introduces a new dependency on `serde`; I don't believe that's a problem since bootstrap is compiled with nightly/beta always so proc macros are available. Compile times are slightly longer -- about 2-3x (30 seconds vs. 10 seconds). I don't think this is too big a problem, especially since recompiling bootstrap is somewhat rare. I think we can remove the dependency on Serde if necessary, though, so let me know.
r? @alexcrichton
