CFI: Strip auto traits off Virtual calls
We already use `Instance` at declaration sites when available to glean additional information about possible abstractions of the type in use. This does the same when possible at callsites as well.
The primary purpose of this change is to allow CFI to alter how it generates type information for indirect calls through `Virtual` instances.
This is needed for the "separate machinery" version of my approach to the vtable issues (#122573), because we need to respond differently to a `Virtual` call to the same type as a non-virtual call, specifically [stripping auto traits off the receiver's `Self`](54b15b0c36) because there isn't a separate vtable for `Foo` vs `Foo + Send`.
This would also make a more general underlying mechanism that could be used by rcvalle's [proposed drop detection / encoding](edcd1e20a1) if we end up using his approach, as we could condition out on the `def_id` in the CFI code rather than requiring the generating code to explicitly note whether it was calling drop.
We already use `Instance` at declaration sites when available to glean
additional information about possible abstractions of the type in use.
This does the same when possible at callsites as well.
The primary purpose of this change is to allow CFI to alter how it
generates type information for indirect calls through `Virtual`
instances.
Let codegen decide when to `mem::swap` with immediates
Making `libcore` decide this is silly; the backend has so much better information about when it's a good idea.
Thus this PR introduces a new `typed_swap` intrinsic with a fallback body, and replaces that fallback implementation when swapping immediates or scalar pairs.
r? oli-obk
Replaces #111744, and means we'll never need more libs PRs like #111803 or #107140
The payload of coverage statements was historically a structure with several
fields, so it was boxed to avoid bloating `StatementKind`.
Now that the payload is a single relatively-small enum, we can replace
`Box<Coverage>` with just `CoverageKind`.
This patch also adds a size assertion for `StatementKind`, to avoid
accidentally bloating it in the future.
Remove `TypeAndMut` from `ty::RawPtr` variant, make it take `Ty` and `Mutability`
Pretty much mechanically converting `ty::RawPtr(ty::TypeAndMut { ty, mutbl })` to `ty::RawPtr(ty, mutbl)` and its fallout.
r? lcnr
cc rust-lang/types-team#124
"Handle" calls to upstream monomorphizations in compiler_builtins
This is pretty cooked, but I think it works.
compiler-builtins has a long-standing problem that at link time, its rlib cannot contain any calls to `core`. And yet, in codegen we _love_ inserting calls to symbols in `core`, generally from various panic entrypoints.
I intend this PR to attack that problem as completely as possible. When we generate a function call, we now check if we are generating a function call from `compiler_builtins` and whether the callee is a function which was not lowered in the current crate, meaning we will have to link to it.
If those conditions are met, actually generating the call is asking for a linker error. So we don't. If the callee diverges, we lower to an abort with the same behavior as `core::intrinsics::abort`. If the callee does not diverge, we produce an error. This means that compiler-builtins can contain panics, but they'll SIGILL instead of panicking. I made non-diverging calls a compile error because I'm guessing that they'd mostly get into compiler-builtins by someone making a mistake while working on the crate, and compile errors are better than linker errors. We could turn such calls into aborts as well if that's preferred.
This skips emitting extra arguments at every callsite (of which there
can be many). For a librustc_driver build with overflow checks enabled,
this cuts 0.7MB from the resulting binary.
Backend and target selection is a mess: the target can override the
backend (via `Target::default_codegen_backend`), *and* the backend can
override the target (via `CodegenBackend::target_override`).
The code that handles this is ugly. It calls `build_target_config`
twice, once before getting the backend and once again afterward. It also
must check that both overrides aren't triggering at the same time.
This commit removes the latter override. It's used in rust-gpu but
@eddyb said via Zulip that removing it would be ok. This simplifies the
code greatly, and will allow some nice follow-up refactorings.
LLD parses @ files like the command arguments on the platform it's on,
so on windows it needs to follow the MSVC style to work correctly.
Otherwise builds can fail if the linker command gets too long and the
build path contains spaces.
Fix ICE: `global_asm!()` Don't Panic When Unable to Evaluate Constant
Fixes#121099
A bit of an inelegant fix but given that the error is created only
after call to `const_eval_poly()` and that the calling function
cannot propagate the error anywhere else, the error has to be
explicitly handled inside `mono_item.rs`.
r? `@Amanieu`
Stabilize associated type bounds (RFC 2289)
This PR stabilizes associated type bounds, which were laid out in [RFC 2289]. This gives us a shorthand to express nested type bounds that would otherwise need to be expressed with nested `impl Trait` or broken into several `where` clauses.
### What are we stabilizing?
We're stabilizing the associated item bounds syntax, which allows us to put bounds in associated type position within other bounds, i.e. `T: Trait<Assoc: Bounds...>`. See [RFC 2289] for motivation.
In all position, the associated type bound syntax expands into a set of two (or more) bounds, and never anything else (see "How does this differ[...]" section for more info).
Associated type bounds are stabilized in four positions:
* **`where` clauses (and APIT)** - This is equivalent to breaking up the bound into two (or more) `where` clauses. For example, `where T: Trait<Assoc: Bound>` is equivalent to `where T: Trait, <T as Trait>::Assoc: Bound`.
* **Supertraits** - Similar to above, `trait CopyIterator: Iterator<Item: Copy> {}`. This is almost equivalent to breaking up the bound into two (or more) `where` clauses; however, the bound on the associated item is implied whenever the trait is used. See #112573/#112629.
* **Associated type item bounds** - This allows constraining the *nested* rigid projections that are associated with a trait's associated types. e.g. `trait Trait { type Assoc: Trait2<Assoc2: Copy>; }`.
* **opaque item bounds (RPIT, TAIT)** - This allows constraining associated types that are associated with the opaque without having to *name* the opaque. For example, `impl Iterator<Item: Copy>` defines an iterator whose item is `Copy` without having to actually name that item bound.
The latter three are not expressible in surface Rust (though for associated type item bounds, this will change in #120752, which I don't believe should block this PR), so this does represent a slight expansion of what can be expressed in trait bounds.
### How does this differ from the RFC?
Compared to the RFC, the current implementation *always* desugars associated type bounds to sets of `ty::Clause`s internally. Specifically, it does *not* introduce a position-dependent desugaring as laid out in [RFC 2289], and in particular:
* It does *not* desugar to anonymous associated items in associated type item bounds.
* It does *not* desugar to nested RPITs in RPIT bounds, nor nested TAITs in TAIT bounds.
This position-dependent desugaring laid out in the RFC existed simply to side-step limitations of the trait solver, which have mostly been fixed in #120584. The desugaring laid out in the RFC also added unnecessary complication to the design of the feature, and introduces its own limitations to, for example:
* Conditionally lowering to nested `impl Trait` in certain positions such as RPIT and TAIT means that we inherit the limitations of RPIT/TAIT, namely lack of support for higher-ranked opaque inference. See this code example: https://github.com/rust-lang/rust/pull/120752#issuecomment-1979412531.
* Introducing anonymous associated types makes traits no longer object safe, since anonymous associated types are not nameable, and all associated types must be named in `dyn` types.
This last point motivates why this PR is *not* stabilizing support for associated type bounds in `dyn` types, e.g, `dyn Assoc<Item: Bound>`. Why? Because `dyn` types need to have *concrete* types for all associated items, this would necessitate a distinct lowering for associated type bounds, which seems both complicated and unnecessary compared to just requiring the user to write `impl Trait` themselves. See #120719.
### Implementation history:
Limited to the significant behavioral changes and fixes and relevant PRs, ping me if I left something out--
* #57428
* #108063
* #110512
* #112629
* #120719
* #120584Closes#52662
[RFC 2289]: https://rust-lang.github.io/rfcs/2289-associated-type-bounds.html
A bit of an inelegant fix but given that the error is created only
after call to `const_eval_poly()` and that the calling function
cannot propagate the error anywhere else, the error has to be
explicitly handled inside `mono_item.rs`.
Remove fixme about LLVM basic block naming
~This may be a small perf win.~
Originally, this PR implemented the fixme, but it didn't have any measurable perf improvement.
r? ``@ghost``
Making `libcore` decide this is silly; the backend has so much better information about when it's a good idea.
So introduce a new `typed_swap` intrinsic with a fallback body, but replace that implementation for immediates and scalar pairs.
link.exe: Don't embed full path to PDB file in binary.
This PR makes `rustc` unconditionally pass `/PDBALTPATH:%_PDB%` to MSVC-style linkers, causing the linker to only embed the filename of the PDB in the binary instead of the full path. This will help implement the [trim-paths RFC](https://github.com/rust-lang/rust/issues/111540) for `*-msvc` targets.
Passing `/PDBALTPATH:%_PDB%` to the linker is already done by many projects that need reproducible builds and [debugger's should still be able to find the PDB](https://learn.microsoft.com/cpp/build/reference/pdbpath) if it is in the same directory as the binary.
r? `@ghost`
Fixes https://github.com/rust-lang/rust/issues/87825
Add `-Z external-clangrt`
This adds the unstable `-Z external-clangrt` flag that will prevent rustc from emitting linker paths for the in-tree LLVM sanitizer runtime library.
[AIX] Remove AixLinker's debuginfo() implementation
AIX ld's `-s` option doesn't perfectly fit` debuginfo()`'s semantics and may unexpectedly remove metadata in shared libraries. Remove the implementation of `AixLinker` and suggest user to use `strip` utility instead.
add test ensuring simd codegen checks don't run when a static assertion failed
stdarch relies on this to ensure that SIMD indices are in bounds.
I would love to know why this works, but I can't figure out where codegen decides to not codegen a function if a required-const does not evaluate. `@oli-obk` `@bjorn3` do you have any idea?
This adds the unstable `-Z external-sanitizer-runtime` flag that will
prevent rustc from emitting linker paths for the in-tree LLVM sanitizer
runtime library.
Avoid lowering code under dead SwitchInt targets
The objective of this PR is to detect and eliminate code which is guarded by an `if false`, even if that `false` is a constant which is not known until monomorphization, or is `intrinsics::debug_assertions()`.
The effect of this is that we generate no LLVM IR the standard library's unsafe preconditions, when they are compiled in a build where they should be immediately optimized out. This mono-time optimization ensures that builds which disable debug assertions do not grow a linkage requirement against `core`, which compiler-builtins currently needs: https://github.com/rust-lang/rust/issues/121552
This revives the codegen side of https://github.com/rust-lang/rust/pull/91222 as planned in https://github.com/rust-lang/rust/issues/120848.
Only generate a ptrtoint in AtomicPtr codegen when absolutely necessary
This special case was added in this PR: https://github.com/rust-lang/rust/pull/77611 in response to this error message:
```
Intrinsic has incorrect argument type!
void ({}*)* `@llvm.ppc.cfence.p0sl_s`
in function rust_oom
LLVM ERROR: Broken function found, compilation aborted!
[RUSTC-TIMING] std test:false 20.161
error: could not compile `std`
```
But when I tried searching for more information about that intrinsic I found this: https://github.com/llvm/llvm-project/issues/55983 which is a report of someone hitting this same error and a fix was landed in LLVM, 2 years after the above Rust PR.
Ensure nested allocations in statics neither get deduplicated nor duplicated
This PR generates new `DefId`s for nested allocations in static items and feeds all the right queries to make the compiler believe these are regular `static` items. I chose this design, because all other designs are fragile and make the compiler horribly complex for such a niche use case.
At present this wrecks incremental compilation performance *in case nested allocations exist* (because any query creating a `DefId` will be recomputed and never loaded from the cache). This will be resolved later in https://github.com/rust-lang/rust/pull/115613 . All other statics are unaffected by this change and will not have performance regressions (heh, famous last words)
This PR contains various smaller refactorings that can be pulled out into separate PRs. It is best reviewed commit-by-commit. The last commit is where the actual magic happens.
r? `@RalfJung` on the const interner and engine changes
fixes https://github.com/rust-lang/rust/issues/79738
Lower transmutes from int to pointer type as gep on null
I thought of this while looking at https://github.com/rust-lang/rust/pull/121242. See that PR's description for why this lowering is preferable.
The UI test that's being changed here crashes without changing the transmutes into casts. Based on that, this PR should not be merged without a crater build-and-test run.
Use ptradd for vtable indexing
Extension of #121665.
After this, the only remaining usages of GEP are [this](cd81f5b27e/compiler/rustc_codegen_llvm/src/intrinsic.rs (L909-L920)) kinda janky Emscription EH code, which I'll change in a future PR, and array indexing / pointer offsets, where there isn't yet a canonical `ptradd` form. (Out of curiosity I tried converting the latter to `ptradd(ptr, mul(size, index))`, but that causes codegen regressions right now.)
r? `@nikic`
std support for wasm32 panic=unwind
Tracking issue: #118168
This adds std support for `-Cpanic=unwind` on wasm, and with it slightly more fleshed out rustc support. Now, the stable default is still panic=abort without exception-handling, but if you `-Zbuild-std` with `RUSTFLAGS=-Cpanic=unwind`, you get wasm exception-handling try/catch blocks in the binary:
```rust
#[no_mangle]
pub fn foo_bar(x: bool) -> *mut u8 {
let s = Box::<str>::from("hello");
maybe_panic(x);
Box::into_raw(s).cast()
}
#[inline(never)]
#[no_mangle]
fn maybe_panic(x: bool) {
if x {
panic!("AAAAA");
}
}
```
```wat
;; snip...
(try $label$5
(do
(call $maybe_panic
(local.get $0)
)
(br $label$1)
)
(catch_all
(global.set $__stack_pointer
(local.get $1)
)
(call $__rust_dealloc
(local.get $2)
(i32.const 5)
(i32.const 1)
)
(rethrow $label$5)
)
)
;; snip...
```
LLVM Bitcode Linker: A self contained linker for nvptx and other targets
This PR introduces a new linker named `llvm-bitcode-linker`. It is a `self-contained` linker that can be used to link programs in `llbc` before optimizing and compiling to native code. It will first be used internally in the Rust compiler to enable tests for the `nvptx64-nvidia-cuda` target as the original `rust-ptx-linker` is deprecated. It will then be provided to users of the `nvptx64-nvidia-cuda` target with the purpose of linking ptx. More targets than nvptx will also be supported eventually.
The PR introduces a new unstable `LinkerFlavor` for the compiler. The compiler will also not be shipped with rustc but most likely instead be shipped in it's own unstable component (a follow up PR will be opened for this). This means that merging this PR should not add any stability guarantees.
When more details of `self-contained` is implemented it will only be possible to use the linker when `-Clink-self-contained=+linker` is passed.
<details>
<summary>Original Description</summary>
**When this PR was created it was focused a bit differently. The original text is preserved here in case there's some interests in it**
I have experimenting with approaches to replace the ptx-linker and enable the nvptx target tests again. I think it's time to get some feedback on the approach.
### The problem
The only useful linker for the nvptx target is [this crate](https://github.com/denzp/rust-ptx-linker). Since this linker performs linking on llvm bitcode it needs to track the llvm version of rustc and use the same format. It has not been maintained for 3+ years and must be considered abandoned. Over the years rust have upgraded LLVM while the linker has been left to bitrot. It is no longer in a usable state.
Due to the difficulty of keeping the ptx-linker up to date outside of tree the nvptx tests was [disabled a long time ago](f8f9a2869c). It was [previously discussed](https://github.com/rust-lang/rust/pull/96842#issuecomment-1146470177) if adding the ptx-linker to the rust repo would be a possibility. My efforts in doing this stopped at getting an answered if the license would prohibit it from inclusion in the [Rust repo](https://github.com/rust-lang/rust/pull/96842#issuecomment-1148397554). I therefore concluded that a re-write would be necessary.
### The possible solution presented here
The llvm tools know perfectly well how to link and optimize llvm bitcode. Each of them only perform a single task, and are therefore a bit cumbersome to call with the current linker approach rustc takes.
This PR adds a simple tool (current name `embedded-linker`) which can link self contained (often embedded) programs in llvm bitcode before compiling to the target format. Optimization will also be performed if lto is enabled. The rust compiler will make a single invocation to this tool, while the tool will orchestrate the many calls to the llvm tools.
### The questions
- Is having control over the nvptx linking and therefore also tests worth it to add such tool? or should the tool live outside the rust repo?
- Is the approach of calling llvm tools acceptable? Or would we want to keep the ptx-linker approach of using the llvm library? The tools seems to provide more simplicity and stability, but more intermediate files are being written. Perhaps there also are some performance penalty for the calling tools approach.
- What is the process for adding such tool? MCP?
- Does adding `llvm-link` to the llvm-tool component require any process?
- Does it require some sort of FCP to remove ptx-linker as the default linker for ptx? Or is it sufficient that using the upstream ptx-linker is broken in its current state. it is possible to use a somewhat patched version of ptx-linker.
</details>
Distinguish between library and lang UB in assert_unsafe_precondition
As described in https://github.com/rust-lang/rust/pull/121583#issuecomment-1963168186, `assert_unsafe_precondition` now explicitly distinguishes between language UB (conditions we explicitly optimize on) and library UB (things we document you shouldn't do, and maybe some library internals assume you don't do).
`debug_assert_nounwind` was originally added to avoid the "only at runtime" aspect of `assert_unsafe_precondition`. Since then the difference between the macros has gotten muddied. This totally revamps the situation.
Now _all_ preconditions shall be checked with `assert_unsafe_precondition`. If you have a precondition that's only checkable at runtime, do a `const_eval_select` hack, as done in this PR.
r? RalfJung
Fix misaligned loads when loading UEFI arg pointers
Currently, the two UEFI argument pointers are stored in an `alloca` of alignment 1, a pointer to which is then passed as `argv`. However, [the library code](9c3ad802d9/library/std/src/sys/pal/uefi/mod.rs (L60-L61)) treats `argv` as a pointer to an array of pointers and dereferences it as such, meaning that it presumes the `alloca` is aligned to at least the alignment of a pointer. This PR fixes this mismatch by aligning the `alloca` to the alignment of a pointer.
This PR also changed the `gep` to use the new `inbounds_ptradd` method.
Add asm goto support to `asm!`
Tracking issue: #119364
This PR implements asm-goto support, using the syntax described in "future possibilities" section of [RFC2873](https://rust-lang.github.io/rfcs/2873-inline-asm.html#asm-goto).
Currently I have only implemented the `label` part, not the `fallthrough` part (i.e. fallthrough is implicit). This doesn't reduce the expressive though, since you can use label-break to get arbitrary control flow or simply set a value and rely on jump threading optimisation to get the desired control flow. I can add that later if deemed necessary.
r? ``@Amanieu``
cc ``@ojeda``
Introduces the `arm64ec-pc-windows-msvc` target for building Arm64EC ("Emulation Compatible") binaries for Windows.
For more information about Arm64EC see <https://learn.microsoft.com/en-us/windows/arm/arm64ec>.
Tier 3 policy:
> A tier 3 target must have a designated developer or developers (the "target maintainers") on record to be CCed when issues arise regarding the target. (The mechanism to track and CC such developers may evolve over time.)
I will be the maintainer for this target.
> Targets must use naming consistent with any existing targets; for instance, a target for the same CPU or OS as an existing Rust target should use the same name for that CPU or OS. Targets should normally use the same names and naming conventions as used elsewhere in the broader ecosystem beyond Rust (such as in other toolchains), unless they have a very good reason to diverge. Changing the name of a target can be highly disruptive, especially once the target reaches a higher tier, so getting the name right is important even for a tier 3 target.
Target uses the `arm64ec` architecture to match LLVM and MSVC, and the `-pc-windows-msvc` suffix to indicate that it targets Windows via the MSVC environment.
> Target names should not introduce undue confusion or ambiguity unless absolutely necessary to maintain ecosystem compatibility. For example, if the name of the target makes people extremely likely to form incorrect beliefs about what it targets, the name should be changed or augmented to disambiguate it.
Target name exactly specifies the type of code that will be produced.
> If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known to cause issues in Cargo.
Done.
> Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or impose onerous legal terms for the Rust project or for Rust developers or users.
> The target must not introduce license incompatibilities.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Understood.
> The target must not cause the Rust tools or libraries built for any other host (even when supporting cross-compilation to the target) to depend on any new dependency less permissive than the Rust licensing policy. This applies whether the dependency is a Rust crate that would require adding new license exceptions (as specified by the tidy tool in the rust-lang/rust repository), or whether the dependency is a native library or binary. In other words, the introduction of the target must not cause a user installing or running a version of Rust or the Rust tools to be subject to any new license requirements.
> Compiling, linking, and emitting functional binaries, libraries, or other code for the target (whether hosted on the target itself or cross-compiling from another target) must not depend on proprietary (non-FOSS) libraries. Host tools built for the target itself may depend on the ordinary runtime libraries supplied by the platform and commonly used by other applications built for the target, but those libraries must not be required for code generation for the target; cross-compilation to the target must not require such libraries at all. For instance, rustc built for the target may depend on a common proprietary C runtime library or console output library, but must not depend on a proprietary code generation library or code optimization library. Rust's license permits such combinations, but the Rust project has no interest in maintaining such combinations within the scope of Rust itself, even at tier 3.
> "onerous" here is an intentionally subjective term. At a minimum, "onerous" legal/licensing terms include but are not limited to: non-disclosure requirements, non-compete requirements, contributor license agreements (CLAs) or equivalent, "non-commercial"/"research-only"/etc terms, requirements conditional on the employer or employment of any particular Rust developers, revocable terms, any requirements that create liability for the Rust project or its developers or users, or any requirements that adversely affect the livelihood or prospects of the Rust project or its developers or users.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> Neither this policy nor any decisions made regarding targets shall create any binding agreement or estoppel by any party. If any member of an approving Rust team serves as one of the maintainers of a target, or has any legal or employment requirement (explicit or implicit) that might affect their decisions regarding a target, they must recuse themselves from any approval decisions regarding the target's tier status, though they may otherwise participate in discussions.
> This requirement does not prevent part or all of this policy from being cited in an explicit contract or work agreement (e.g. to implement or maintain support for a target). This requirement exists to ensure that a developer or team responsible for reviewing and approving a target does not face any legal threats or obligations that would prevent them from freely exercising their judgment in such approval, even if such judgment involves subjective matters or goes beyond the letter of these requirements.
Understood, I am not a member of the Rust team.
> Tier 3 targets should attempt to implement as much of the standard libraries as possible and appropriate (core for most targets, alloc for targets that can support dynamic memory allocation, std for targets with an operating system or equivalent layer of system-provided functionality), but may leave some code unimplemented (either unavailable or stubbed out as appropriate), whether because the target makes it impossible to implement or challenging to implement. The authors of pull requests are not obligated to avoid calling any portions of the standard library on the basis of a tier 3 target not implementing those portions.
Both `core` and `alloc` are supported.
Support for `std` dependends on making changes to the standard library, `stdarch` and `backtrace` which cannot be done yet as the bootstrapping compiler raises a warning ("unexpected `cfg` condition value") for `target_arch = "arm64ec"`.
> The target must provide documentation for the Rust community explaining how to build for the target, using cross-compilation if possible. If the target supports running binaries, or running tests (even if they do not pass), the documentation must explain how to run such binaries or tests for the target, using emulation if possible or dedicated hardware if necessary.
Documentation is provided in src/doc/rustc/src/platform-support/arm64ec-pc-windows-msvc.md
> Tier 3 targets must not impose burden on the authors of pull requests, or other developers in the community, to maintain the target. In particular, do not post comments (automated or manual) on a PR that derail or suggest a block on the PR based on a tier 3 target. Do not send automated messages or notifications (via any medium, including via @) to a PR author or others involved with a PR regarding a tier 3 target, unless they have opted into such messages.
> Backlinks such as those generated by the issue/PR tracker when linking to an issue or PR are not considered a violation of this policy, within reason. However, such messages (even on a separate repository) must not generate notifications to anyone involved with a PR who has not requested such notifications.
> Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target, and must not knowingly break another tier 3 target without approval of either the compiler team or the maintainers of the other tier 3 target.
> In particular, this may come up when working on closely related targets, such as variations of the same architecture with different features. Avoid introducing unconditional uses of features that another variation of the target may not have; use conditional compilation or runtime detection, as appropriate, to let each target run code supported by that target.
Understood.
cleanup: remove zero-offset GEP
This GEP would've been used to change the pointer type in the past, but after opaque pointers it's a no-op. I missed removing this in #105545.
Split out from #121577.
This always produces zero offset, regardless of what the struct layout
is.
Originally, this may have been necessary in order to change the pointer type,
but with opaque pointers, it is no longer necessary.
`-s` option doesn't perfectly fit into debuginfo()'s semantics and may unexpectedly
remove metadata in shared libraries. Remove the implementation and suggest user to
use `strip` utility instead.
Add a scheme for moving away from `extern "rust-intrinsic"` entirely
All `rust-intrinsic`s can become free functions now, either with a fallback body, or with a dummy body and an attribute, requiring backends to actually implement the intrinsic.
This PR demonstrates the dummy-body scheme with the `vtable_size` intrinsic.
cc https://github.com/rust-lang/rust/issues/63585
follow-up to #120500
MCP at https://github.com/rust-lang/compiler-team/issues/720
Existing names for values of this type are `sess`, `parse_sess`,
`parse_session`, and `ps`. `sess` is particularly annoying because
that's also used for `Session` values, which are often co-located, and
it can be difficult to know which type a value named `sess` refers to.
(That annoyance is the main motivation for this change.) `psess` is nice
and short, which is good for a name used this much.
The commit also renames some `parse_sess_created` values as
`psess_created`.
For the former, it's fine for `inbounds` offsets to be one-past-the-end,
so it's okay even if the ZST is the last field in the layout:
> The base pointer has an in bounds address of an allocated object,
> which means that it points into an allocated object, or to its end.
https://llvm.org/docs/LangRef.html#getelementptr-instruction
For the latter, even DST fields must always be inside the layout
(or to its end for ZSTs), so using inbounds is also fine there.
Adds initial support for DataFlowSanitizer to the Rust compiler. It
currently supports `-Zsanitizer-dataflow-abilist`. Additional options
for it can be passed to LLVM command line argument processor via LLVM
arguments using `llvm-args` codegen option (e.g.,
`-Cllvm-args=-dfsan-combine-pointer-labels-on-load=false`).
Add profiling support to AIX
AIX ld needs special option to merge objects with profiling. Also, profiler_builtins should include builtins for AIX from compiler-rt.
Add stubs in IR and ABI for `f16` and `f128`
This is the very first step toward the changes in https://github.com/rust-lang/rust/pull/114607 and the [`f16` and `f128` RFC](https://rust-lang.github.io/rfcs/3453-f16-and-f128.html). It adds the types to `rustc_type_ir::FloatTy` and `rustc_abi::Primitive`, and just propagates those out as `unimplemented!` stubs where necessary.
These types do not parse yet so there is no feature gate, and it should be okay to use `unimplemented!`.
The next steps will probably be AST support with parsing and the feature gate.
r? `@compiler-errors`
cc `@Nilstrieb` suggested breaking the PR up in https://github.com/rust-lang/rust/pull/120645#issuecomment-1925900572
rustc: Fix wasm64 metadata object files
It looks like LLD will detect object files being either 32 or 64-bit depending on any memory present. LLD will additionally reject 32-bit objects during a 64-bit link. Previously metadata objects did not have any memories in them which led LLD to conclude they were 32-bit objects which broke 64-bit targets for wasm.
This commit fixes this by ensuring that for 64-bit targets there's a memory object present to get LLD to detect it's a 64-bit target. Additionally this commit moves away from a hand-crafted wasm encoder to the `wasm-encoder` crate on crates.io as the complexity grows for the generated object file.
Closes#121460
Note the change of the `D` to `d`, to match all the other names that
have `Subdiag` in them, such as `SubdiagnosticMessage` and
`derive(Subdiagnostic)`.
Remove useless lifetime of ArchiveBuilder
`trait ArchiveBuilder<'a>` has a seemingly useless lifetime a, so I remove it. If this is intentional, please reject this PR.
```rust
pub trait ArchiveBuilder<'a> {
fn add_file(&mut self, path: &Path);
fn add_archive(
&mut self,
archive: &Path,
skip: Box<dyn FnMut(&str) -> bool + 'static>,
) -> io::Result<()>;
fn build(self: Box<Self>, output: &Path) -> bool;
}
```
It looks like LLD will detect object files being either 32 or 64-bit
depending on any memory present. LLD will additionally reject 32-bit
objects during a 64-bit link. Previously metadata objects did not have
any memories in them which led LLD to conclude they were 32-bit objects
which broke 64-bit targets for wasm.
This commit fixes this by ensuring that for 64-bit targets there's a
memory object present to get LLD to detect it's a 64-bit target.
Additionally this commit moves away from a hand-crafted wasm encoder to
the `wasm-encoder` crate on crates.io as the complexity grows for the
generated object file.
Closes#121460
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.
Because it's almost always static.
This makes `impl IntoDiagnosticArg for DiagnosticArgValue` trivial,
which is nice.
There are a few diagnostics constructed in
`compiler/rustc_mir_build/src/check_unsafety.rs` and
`compiler/rustc_mir_transform/src/errors.rs` that now need symbols
converted to `String` with `to_string` instead of `&str` with `as_str`,
but that' no big deal, and worth it for the simplifications elsewhere.
Error codes are integers, but `String` is used everywhere to represent
them. Gross!
This commit introduces `ErrCode`, an integral newtype for error codes,
replacing `String`. It also introduces a constant for every error code,
e.g. `E0123`, and removes the `error_code!` macro. The constants are
imported wherever used with `use rustc_errors::codes::*`.
With the old code, we have three different ways to specify an error code
at a use point:
```
error_code!(E0123) // macro call
struct_span_code_err!(dcx, span, E0123, "msg"); // bare ident arg to macro call
\#[diag(name, code = "E0123")] // string
struct Diag;
```
With the new code, they all use the `E0123` constant.
```
E0123 // constant
struct_span_code_err!(dcx, span, E0123, "msg"); // constant
\#[diag(name, code = E0123)] // constant
struct Diag;
```
The commit also changes the structure of the error code definitions:
- `rustc_error_codes` now just defines a higher-order macro listing the
used error codes and nothing else.
- Because that's now the only thing in the `rustc_error_codes` crate, I
moved it into the `lib.rs` file and removed the `error_codes.rs` file.
- `rustc_errors` uses that macro to define everything, e.g. the error
code constants and the `DIAGNOSTIC_TABLES`. This is in its new
`codes.rs` file.
Remove unused/unnecessary features
~~The bulk of the actual code changes here is replacing try blocks with equivalent closures. I'm not entirely sure that's a good idea since it may have perf impact, happy to revert if that's the case/the change is unwanted.~~
I also removed a lot of `recursion_limit = "256"` since everything seems to build fine without that and most don't have any comment justifying it.
linker: Refactor library linking methods in `trait Linker`
Linkers are not aware of Rust libraries, they look like regular static or dynamic libraries to them, so Rust-specific methods in `trait Linker` do not make much sense.
They can be either removed or renamed to something more suitable.
Commits after the second one are cleanups.
Do not normalize closure signature when building `FnOnce` shim
It is not necessary to normalize the closure signature when building an `FnOnce` shim for an `Fn`/`FnMut` closure. That closure shim is just calling `FnMut::call_mut(&mut self)` anyways.
It's also somewhat sketchy that we were ever doing this to begin with, since we're normalizing with a `ParamEnv::reveal_all()` param-env, which is definitely not right with possibly polymorphic substs.
This cuts out a tiny bit of unnecessary work in `Instance::resolve` and simplifies the signature because now we can unconditionally return an `Instance`.
Pack u128 in the compiler to mitigate new alignment
This is based on #116672, adding a new `#[repr(packed(8))]` wrapper on `u128` to avoid changing any of the compiler's size assertions. This is needed in two places:
* `SwitchTargets`, otherwise its `SmallVec<[u128; 1]>` gets padded up to 32 bytes.
* `LitKind::Int`, so that entire `enum` can stay 24 bytes.
* This change definitely has far-reaching effects though, since it's public.
