Add the intrinsic
declare {i8*, i1} @llvm.type.checked.load(i8* %ptr, i32 %offset, metadata %type)
This is used in the VFE optimization when lowering loading functions
from vtables to LLVM IR. The `metadata` is used to map the function to
all vtables this function could belong to. This ensures that functions
from vtables that might be used somewhere won't get removed.
It looks like the last time had left some remaining cfg's -- which made me think
that the stage0 bump was actually successful. This brings us to a released 1.62
beta though.
`Layout` is another type that is sometimes interned, sometimes not, and
we always use references to refer to it so we can't take any advantage
of the uniqueness properties for hashing or equality checks.
This commit renames `Layout` as `LayoutS`, and then introduces a new
`Layout` that is a newtype around an `Interned<LayoutS>`. It also
interns more layouts than before. Previously layouts within layouts
(via the `variants` field) were never interned, but now they are. Hence
the lifetime on the new `Layout` type.
Unlike other interned types, these ones are in `rustc_target` instead of
`rustc_middle`. This reflects the existing structure of the code, which
does layout-specific stuff in `rustc_target` while `TyAndLayout` is
generic over the `Ty`, allowing the type-specific stuff to occur in
`rustc_middle`.
The commit also adds a `HashStable` impl for `Interned`, which was
needed. It hashes the contents, unlike the `Hash` impl which hashes the
pointer.
Specifically, change `Ty` from this:
```
pub type Ty<'tcx> = &'tcx TyS<'tcx>;
```
to this
```
pub struct Ty<'tcx>(Interned<'tcx, TyS<'tcx>>);
```
There are two benefits to this.
- It's now a first class type, so we can define methods on it. This
means we can move a lot of methods away from `TyS`, leaving `TyS` as a
barely-used type, which is appropriate given that it's not meant to
be used directly.
- The uniqueness requirement is now explicit, via the `Interned` type.
E.g. the pointer-based `Eq` and `Hash` comes from `Interned`, rather
than via `TyS`, which wasn't obvious at all.
Much of this commit is boring churn. The interesting changes are in
these files:
- compiler/rustc_middle/src/arena.rs
- compiler/rustc_middle/src/mir/visit.rs
- compiler/rustc_middle/src/ty/context.rs
- compiler/rustc_middle/src/ty/mod.rs
Specifically:
- Most mentions of `TyS` are removed. It's very much a dumb struct now;
`Ty` has all the smarts.
- `TyS` now has `crate` visibility instead of `pub`.
- `TyS::make_for_test` is removed in favour of the static `BOOL_TY`,
which just works better with the new structure.
- The `Eq`/`Ord`/`Hash` impls are removed from `TyS`. `Interned`s impls
of `Eq`/`Hash` now suffice. `Ord` is now partly on `Interned`
(pointer-based, for the `Equal` case) and partly on `TyS`
(contents-based, for the other cases).
- There are many tedious sigil adjustments, i.e. adding or removing `*`
or `&`. They seem to be unavoidable.
Improve SIMD casts
* Allows `simd_cast` intrinsic to take `usize` and `isize`
* Adds `simd_as` intrinsic, which is the same as `simd_cast` except for saturating float-to-int conversions (matching the behavior of `as`).
cc `@workingjubilee`
This commit adds LLVM Control Flow Integrity (CFI) support to the Rust
compiler. It initially provides forward-edge control flow protection for
Rust-compiled code only by aggregating function pointers in groups
identified by their number of arguments.
Forward-edge control flow protection for C or C++ and Rust -compiled
code "mixed binaries" (i.e., for when C or C++ and Rust -compiled code
share the same virtual address space) will be provided in later work as
part of this project by defining and using compatible type identifiers
(see Type metadata in the design document in the tracking issue #89653).
LLVM CFI can be enabled with -Zsanitizer=cfi and requires LTO (i.e.,
-Clto).
Querify `FnAbi::of_{fn_ptr,instance}` as `fn_abi_of_{fn_ptr,instance}`.
*Note: opening this PR as draft because it's based on #88499*
This more or less replicates the `LayoutOf::layout_of` setup from #88499, to replace `FnAbi::of_{fn_ptr,instance}` with `FnAbiOf::fn_abi_of_{fn_ptr,instance}`, and also route them through queries (which `layout_of` has used for a while).
The two changes at the use sites (other than the names) are:
* return type is now wrapped in `&'tcx`
* the value *is* interned, which may affect performance
* the `extra_args` list is now an interned `&'tcx ty::List<Ty<'tcx>>`
* should be cheap (it's empty for anything other than C variadics)
Theoretically, a `FnAbiOfHelpers` implementer could choose to keep the `Result<...>` instead of eagerly erroring, but the only existing users of these APIs are codegen backends, so they don't (want to) take advantage of this.
At least miri could make use of this, since it prefers propagating errors (it "just" doesn't use `FnAbi` yet - cc `@RalfJung).`
The way this is done is probably less efficient than what is possible, because the queries handle the correctness-oriented API (i.e. the split into `fn` pointers vs instances), whereas a lower-level query could end up with more reuse between different instances with identical signatures.
r? `@nagisa` cc `@oli-obk` `@bjorn3`
The new implementation allows some `memcpy`s to be optimized away,
so the uninit value in ui/sanitize/memory.rs is constructed directly
onto the return place. Therefore the sanitizer now says that the
value is allocated by `main` rather than `random`.
Rather than relying on `getPointerElementType()` from LLVM function
pointers, we now pass the function type explicitly when building `call`
or `invoke` instructions.
This makes load generation compatible with opaque pointers.
The generation of nontemporal copies still accesses the pointer
element type, as fixing this requires more movement.
This PR adds ability for the target specifications to specify frame
pointer emission type that's not just “always” or “whatever cg decides”.
In particular there's a new mode that allows omission of the frame
pointer for leaf functions (those that don't call any other functions).
We then set this new mode for Aarch64-based Apple targets.
Fixes#86196
