Improve codegen diagnostic handling
Clarify the workings of the temporary `Diagnostic` type used to send diagnostics from codegen threads to the main thread.
r? `@estebank`
- Make it more closely match `rustc_errors::Diagnostic`, by making the
field names match, and adding `children`, which requires adding
`rustc_codegen_ssa:🔙:write::Subdiagnostic`.
- Check that we aren't missing important info when converting
diagnostics.
- Add better comments.
- Tweak `rustc_errors::Diagnostic::replace_args` so that we don't need
to do any cloning when converting diagnostics.
First, introduce a typedef `DiagnosticArgMap`.
Second, make the `args` field public, and remove the `args` getter and
`replace_args` setter. These were necessary previously because the getter
had a `#[allow(rustc::potential_query_instability)]` attribute, but that
was removed in #120931 when the args were changed from `FxHashMap` to
`FxIndexMap`. (All the other `Diagnostic` fields are public.)
Add "algebraic" fast-math intrinsics, based on fast-math ops that cannot return poison
Setting all of LLVM's fast-math flags makes our fast-math intrinsics very dangerous, because some inputs are UB. This set of flags permits common algebraic transformations, but according to the [LangRef](https://llvm.org/docs/LangRef.html#fastmath), only the flags `nnan` (no nans) and `ninf` (no infs) can produce poison.
And this uses the algebraic float ops to fix https://github.com/rust-lang/rust/issues/120720
cc `@orlp`
The goal of this commit is to remove warnings using LLVM tip-of-tree
`wasm-ld`. In llvm/llvm-project#78658 the `wasm-ld` LLD driver no longer
looks at archive indices and instead looks at all the objects in
archives. Previously `lib.rmeta` files were simply raw rustc metadata
bytes, not wasm objects, meaning that `wasm-ld` would emit a warning
indicating so.
WebAssembly targets previously passed `--fatal-warnings` to `wasm-ld` by
default which meant that if Rust were to update to LLVM 18 then all wasm
targets would not work. This immediate blocker was resolved in
rust-lang/rust#120278 which removed `--fatal-warnings` which enabled a
theoretical update to LLVM 18 for wasm targets. This current state is
ok-enough for now because rustc squashes all linker output by default if
it doesn't fail. This means, for example, that rustc squashes all the
linker warnings coming out of `wasm-ld` about `lib.rmeta` files with
LLVM 18. This again isn't a pressing issue because the information is
all hidden, but it runs the risk of being annoying if another linker
error were to happen and then the output would have all these unrelated
warnings that couldn't be fixed.
Thus, this PR comes into the picture. The goal of this PR is to resolve
these warnings by using the WebAssembly object file format on wasm
targets instead of using raw rustc metadata. When I first implemented
the rlib-in-objects scheme in #84449 I remember either concluding that
`wasm-ld` would either include the metadata in the output or I thought
we didn't have to do anything there at all. I think I was wrong on both
counts as `wasm-ld` does not include the metadata in the final output
unless the object is referenced and we do actually need to do something
to resolve these warnings.
This PR updates the object file format containing rustc metadata on
WebAssembly targets to be an actual WebAssembly file. This enables the
`wasm` feature of the `object` crate to be able to read the custom
section in the same manner as other platforms, but currently `object`
doesn't support writing wasm object files so a handwritten encoder is
used instead.
The only caveat I know of with this is that if `wasm-ld` does indeed
look at the object file then the metadata will be included in the final
output. I believe the only thing that could cause that at this time is
`--whole-archive` which I don't think is passed for rlibs. I would
clarify that I'm not 100% certain about this, however.
Overhaul `Diagnostic` and `DiagnosticBuilder`
Implements the first part of https://github.com/rust-lang/compiler-team/issues/722, which moves functionality and use away from `Diagnostic`, onto `DiagnosticBuilder`.
Likely follow-ups:
- Move things around, because this PR was written to minimize diff size, so some things end up in sub-optimal places. E.g. `DiagnosticBuilder` has impls in both `diagnostic.rs` and `diagnostic_builder.rs`.
- Rename `Diagnostic` as `DiagInner` and `DiagnosticBuilder` as `Diag`.
r? `@davidtwco`
Currently many diagnostic modifier methods are available on both
`Diagnostic` and `DiagnosticBuilder`. This commit removes most of them
from `Diagnostic`. To minimize the diff size, it keeps them within
`diagnostic.rs` but changes the surrounding `impl Diagnostic` block to
`impl DiagnosticBuilder`. (I intend to move things around later, to give
a more sensible code layout.)
`Diagnostic` keeps a few methods that it still needs, like `sub`,
`arg`, and `replace_args`.
The `forward!` macro, which defined two additional methods per call
(e.g. `note` and `with_note`), is replaced by the `with_fn!` macro,
which defines one additional method per call (e.g. `with_note`). It's
now also only used when necessary -- not all modifier methods currently
need a `with_*` form. (New ones can be easily added as necessary.)
All this also requires changing `trait AddToDiagnostic` so its methods
take `DiagnosticBuilder` instead of `Diagnostic`, which leads to many
mechanical changes. `SubdiagnosticMessageOp` gains a type parameter `G`.
There are three subdiagnostics -- `DelayedAtWithoutNewline`,
`DelayedAtWithNewline`, and `InvalidFlushedDelayedDiagnosticLevel` --
that are created within the diagnostics machinery and appended to
external diagnostics. These are handled at the `Diagnostic` level, which
means it's now hard to construct them via `derive(Diagnostic)`, so
instead we construct them by hand. This has no effect on what they look
like when printed.
There are lots of new `allow` markers for `untranslatable_diagnostics`
and `diagnostics_outside_of_impl`. This is because
`#[rustc_lint_diagnostics]` annotations were present on the `Diagnostic`
modifier methods, but missing from the `DiagnosticBuilder` modifier
methods. They're now present.
Implement intrinsics with fallback bodies
fixes#93145 (though we can port many more intrinsics)
cc #63585
The way this works is that the backend logic for generating custom code for intrinsics has been made fallible. The only failure path is "this intrinsic is unknown". The `Instance` (that was `InstanceDef::Intrinsic`) then gets converted to `InstanceDef::Item`, which represents the fallback body. A regular function call to that body is then codegenned. This is currently implemented for
* codegen_ssa (so llvm and gcc)
* codegen_cranelift
other backends will need to adjust, but they can just keep doing what they were doing if they prefer (though adding new intrinsics to the compiler will then require them to implement them, instead of getting the fallback body).
cc `@scottmcm` `@WaffleLapkin`
### todo
* [ ] miri support
* [x] default intrinsic name to name of function instead of requiring it to be specified in attribute
* [x] make sure that the bodies are always available (must be collected for metadata)
Turn the "no saved object file in work product" ICE into a translatable fatal error
I don't know if it's fair to say this fixes https://github.com/rust-lang/rust/issues/120854 but it surely makes the error reporting better and should encourage people with good instincts like ```@CinchBlue.```
Invert diagnostic lints.
That is, change `diagnostic_outside_of_impl` and `untranslatable_diagnostic` from `allow` to `deny`, because more than half of the compiler has been converted to use translated diagnostics.
This commit removes more `deny` attributes than it adds `allow` attributes, which proves that this change is warranted.
r? ````@davidtwco````
That is, change `diagnostic_outside_of_impl` and
`untranslatable_diagnostic` from `allow` to `deny`, because more than
half of the compiler has be converted to use translated diagnostics.
This commit removes more `deny` attributes than it adds `allow`
attributes, which proves that this change is warranted.
All the other `emit`/`emit_diagnostic` methods were recently made
consuming (e.g. #119606), but this one wasn't. But it makes sense to.
Much of this is straightforward, and lots of `clone` calls are avoided.
There are a couple of tricky bits.
- `Emitter::primary_span_formatted` no longer takes a `Diagnostic` and
returns a pair. Instead it takes the two fields from `Diagnostic` that
it used (`span` and `suggestions`) as `&mut`, and modifies them. This
is necessary to avoid the cloning of `diag.children` in two emitters.
- `from_errors_diagnostic` is rearranged so various uses of `diag` occur
before the consuming `emit_diagnostic` call.
