Simplify the arguments to macros generated by the `rustc_queries` proc macro
Very small cleanup. Based on https://github.com/rust-lang/rust/pull/100436 which modifies some of the same code.
r? `@cjgillot`
Implementation of import_name_type
Fixes#96534 by implementing https://github.com/rust-lang/compiler-team/issues/525
Symbols that are exported or imported from a binary on 32bit x86 Windows can be named in four separate ways, corresponding to the [import name types](https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#import-name-type) from the PE-COFF spec. The exporting and importing binaries must use the same name encoding, otherwise mismatches can lead to link failures due to "missing symbols" or to 0xc0000139 (`STATUS_ENTRYPOINT_NOT_FOUND`) errors when the executable/library is loaded. For details, see the comments on the raw-dylib feature's https://github.com/rust-lang/rust/issues/58713. To generate the correct import libraries for these DLLs, therefore, rustc must know the import name type for each `extern` function, and there is currently no way for users to provide this information.
This change adds a new `MetaNameValueStr` key to the `#[link]` attribute called `import_name_type`, and which accepts one of three values: `decorated`, `noprefix`, and `undecorated`.
A single DLL is likely to export all its functions using the same import type name, hence `import_name_type` is a parameter of `#[link]` rather than being its own attribute that is applied per-function. It is possible to have a single DLL that exports different functions using different import name types, but users could express such cases by providing multiple export blocks for the same DLL, each with a different import name type.
Note: there is a fourth import name type defined in the PE-COFF spec, `IMPORT_ORDINAL`. This case is already handled by the `#[link_ordinal]` attribute. While it could be merged into `import_type_name`, that would not make sense as `#[link_ordinal]` provides per-function information (namely the ordinal itself).
Design decisions (these match the MCP linked above):
* For GNU, `decorated` matches the PE Spec and MSVC rather than the default behavior of `dlltool` (i.e., there will be a leading `_` for `stdcall`).
* If `import_name_type` is not present, we will keep our current behavior of matching the environment (MSVC vs GNU) default for decorating.
* Using `import_name_type` on architectures other than 32bit x86 will result in an error.
* Using `import_name_type` with link kinds other than `"raw-dylib"` will result in an error.
interpret: remove support for uninitialized scalars
With Miri no longer supporting `-Zmiri-allow-uninit-numbers`, we no longer need to support storing uninit data in a `Scalar`. We anyway already only use this representation for types with *initialized* `Scalar` layout (and we have to, due to partial initialization), so let's get rid of the `ScalarMaybeUninit` type entirely.
I tried to stage this into meaningful commits, but the one that changes `read_immediate` to always trigger UB on uninit is the largest chunk of the PR and I don't see how it could be subdivided.
Fixes https://github.com/rust-lang/miri/issues/2187
r? `@oli-obk`
Elaborate all box dereferences in `ElaborateBoxDerefs`
so that it is the only pass responsible for elaboration, instead of
splitting this responsibility between the `StateTransform` and
`ElaborateBoxDerefs`.
add `depth_limit` in `QueryVTable` to avoid entering a new tcx in `layout_of`
Fixes#49735
Updates #48685
The `layout_of` query needs to check whether it overflows the depth limit, and the current implementation needs to create a new `ImplicitCtxt` inside `layout_of`. However, `start_query` will already create a new `ImplicitCtxt`, so we can check the depth limit in `start_query`.
We can tell whether we need to check the depth limit simply by whether the return value of `to_debug_str` of the query is `layout_of`. But I think adding the `depth_limit` field in `QueryVTable` may be more elegant and more scalable.
Elide superfluous storage markers
Follow the existing strategy of omitting the storage markers for temporaries
introduced for internal usage when elaborating derefs and deref projections.
Those temporaries are simple scalars which are used immediately after being
defined and never have their address taken. There is no benefit from storage
markers from either liveness analysis or code generation perspective.
- Disallow multiple macros callbacks in the same invocation. In practice, this was never used.
- Remove the `[]` brackets around the macro name
- Require an `ident`, not an arbitrary `tt`
implied bounds: explicitly state which types are assumed to be wf
Adds a new query which maps each definition to the types which that definition assumes to be well formed. The intent is to make it easier to reason about implied bounds.
This change should not influence the user-facing behavior of rustc. Notably, `borrowck` still only assumes that the function signature of associated functions is well formed while `wfcheck` assumes that the both the function signature and the impl trait ref is well formed. Not sure if that by itself can trigger UB or whether it's just annoying.
As a next step, we can add `WellFormed` predicates to `predicates_of` of these items and can stop adding the wf bounds at each place which uses them. I also intend to move the computation from `assumed_wf_types` to `implied_bounds` into the `param_env` computation. This requires me to take a deeper look at `compare_predicate_entailment` which is currently somewhat weird wrt implied bounds so I am not touching this here.
r? `@nikomatsakis`
Make `same_type_modulo_infer` a proper `TypeRelation`
Specifically, this fixes#100690 because we no longer consider a `ReLateBound` and a `ReVar` to be equal. `ReVar` can only be equal to free regions or static.
never consider unsafe blocks unused if they would be required with deny(unsafe_op_in_unsafe_fn)
Judging from https://github.com/rust-lang/rust/issues/71668#issuecomment-1200317370 the consensus nowadays seems to be that we should never consider an unsafe block unused if it was required with `deny(unsafe_op_in_unsafe_fn)`, no matter whether that lint is actually enabled or not. So let's adjust rustc accordingly.
The first commit does the change, the 2nd does some cleanup.
avoid assertion failures in try_to_scalar_int
Given that this is called `try_to_scalar_int`, we probably shouldn't `assert_int` here. Similarly `try_to_bits` also doesn't `assert!` that the size is correct.
Also add some `track_caller` for debugging, while we are at it.
r? ```@oli-obk```
Do not report cycle error when inferring return type for suggestion
The UI test is a good example of a case where this happens. The cycle is due to needing the value of the return type `-> _` to compute the variances of items in the crate, but then needing the variances of the items in the crate to do typechecking to infer what `-> _`'s real type is.
Since we're already gonna emit an error in astconv, just delay the cycle bug as an error.
Visit attributes in more places.
This adds 3 loosely related changes (I can split PRs if desired):
- Attribute checking on pattern struct fields.
- Attribute checking on struct expression fields.
- Lint level visiting on pattern struct fields, struct expression fields, and generic parameters.
There are still some lints which ignore lint levels in various positions. This is a consequence of how the lints themselves are implemented. For example, lint levels on associated consts don't work with `unused_braces`.
