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.
Apply noundef attribute to &T, &mut T, Box<T>, bool
This doesn't handle `char` because it's a bit awkward to distinguish it from `u32` at this point in codegen.
Note that this _does not_ change whether or not it is UB for `&`, `&mut`, or `Box` to point to undef. It only applies to the pointer itself, not the pointed-to memory.
Fixes (partially) #74378.
r? `@nikic` cc `@RalfJung`
Split `pauth` target feature
Per discussion on https://github.com/rust-lang/rust/issues/86941 we'd like to split `pauth` into `paca` and `pacg` in order to better support possible future environments that only have the keys available for address or generic authentication. At the moment LLVM has the one `pauth` target_feature while Linux presents separate `paca` and `pacg` flags for feature detection.
Because the use of [target_feature](https://rust-lang.github.io/rfcs/2045-target-feature.html) will "allow the compiler to generate code under the assumption that this code will only be reached in hosts that support the feature", it does not make sense to simply translate `paca` into the LLVM feature `pauth`, as it will generate code as if `pacg` is available.
To accommodate this we error if only one of the two features is present. If LLVM splits them in the future we can remove this restriction without making a breaking change.
r? ```@Amanieu```
debuginfo: Fix DW_AT_containing_type vtable debuginfo regression
This PR brings back the `DW_AT_containing_type` attribute for vtables after it has accidentally been removed in #89597.
It also implements a more accurate description of vtables. Instead of describing them as an array of void pointers, the compiler will now emit a struct type description with a field for each entry of the vtable.
r? ``@wesleywiser``
This PR should fix issue https://github.com/rust-lang/rust/issues/93164.
~~The PR is blocked on https://github.com/rust-lang/rust/pull/93154 because both of them modify the `codegen/debug-vtable.rs` test case.~~
This doesn't handle `char` because it's a bit awkward to distinguish it
from u32 at this point in codegen.
Note that for some types (like `&Struct` and `&mut Struct`),
we already apply `dereferenceable`, which implies `noundef`,
so the IR does not change.
Stabilize `-Z instrument-coverage` as `-C instrument-coverage`
(Tracking issue for `instrument-coverage`: https://github.com/rust-lang/rust/issues/79121)
This PR stabilizes support for instrumentation-based code coverage, previously provided via the `-Z instrument-coverage` option. (Continue supporting `-Z instrument-coverage` for compatibility for now, but show a deprecation warning for it.)
Many, many people have tested this support, and there are numerous reports of it working as expected.
Move the documentation from the unstable book to stable rustc documentation. Update uses and documentation to use the `-C` option.
Addressing questions raised in the tracking issue:
> If/when stabilized, will the compiler flag be updated to -C instrument-coverage? (If so, the -Z variant could also be supported for some time, to ease migrations for existing users and scripts.)
This stabilization PR updates the option to `-C` and keeps the `-Z` variant to ease migration.
> The Rust coverage implementation depends on (and automatically turns on) -Z symbol-mangling-version=v0. Will stabilizing this feature depend on stabilizing v0 symbol-mangling first? If so, what is the current status and timeline?
This stabilization PR depends on https://github.com/rust-lang/rust/pull/90128 , which stabilizes `-C symbol-mangling-version=v0` (but does not change the default symbol-mangling-version).
> The Rust coverage implementation implements the latest version of LLVM's Coverage Mapping Format (version 4), which forces a dependency on LLVM 11 or later. A compiler error is generated if attempting to compile with coverage, and using an older version of LLVM.
Given that LLVM 13 has now been released, requiring LLVM 11 for coverage support seems like a reasonable requirement. If people don't have at least LLVM 11, nothing else breaks; they just can't use coverage support. Given that coverage support currently requires a nightly compiler and LLVM 11 or newer, allowing it on a stable compiler built with LLVM 11 or newer seems like an improvement.
The [tracking issue](https://github.com/rust-lang/rust/issues/79121) and the [issue label A-code-coverage](https://github.com/rust-lang/rust/labels/A-code-coverage) link to a few open issues related to `instrument-coverage`, but none of them seem like showstoppers. All of them seem like improvements and refinements we can make after stabilization.
The original `-Z instrument-coverage` support went through a compiler-team MCP at https://github.com/rust-lang/compiler-team/issues/278 . Based on that, `@pnkfelix` suggested that this needed a stabilization PR and a compiler-team FCP.
Windows: Disable LLVM crash dialog boxes.
This disables the crash dialog box on Windows. When LLVM hits an assertion, it will open a dialog box with Abort/Retry/Ignore. This is annoying on CI because CI will just hang until it times out (which can take hours).
Instead of opening a dialog box, it will print a message like this:
```
Assertion failed: isa<X>(Val) && "cast<Ty>() argument of incompatible type!", file D:\Proj\rust\rust\src\llvm-project\llvm\include\llvm/Support/Casting.h, line 255
```
Closes#92829
The "CI" environment var isn't universal (for example, I think Azure
uses TF_BUILD). However, we are mostly concerned with rust-lang/rust's
own CI which currently is GitHub Actions which does set "CI". And I
think most other providers use "CI" as well.
debuginfo: Make sure that type names for closure and generator environments are unique in debuginfo.
Before this change, closure/generator environments coming from different instantiations of the same generic function were all assigned the same name even though they were distinct types with potentially different data layout. Now we append the generic arguments of the originating function to the type name.
This commit also emits `{closure_env#0}` as the name of these types in order to disambiguate them from the accompanying closure function (which keeps being called `{closure#0}`). Previously both were assigned the same name.
NOTE: Changing debuginfo names like this can break pretty printers and other debugger plugins. I think it's OK in this particular case because the names we are changing were ambiguous anyway. In general though it would be great to have a process for doing changes like these.
Before this change, closure/generator environments coming from different
instantiations of the same generic function were all assigned the same
name even though they were distinct types with potentially different data
layout. Now we append the generic arguments of the originating function
to the type name.
This commit also emits '{closure_env#0}' as the name of these types in
order to disambiguate them from the accompanying closure function
'{closure#0}'. Previously both were assigned the same name.
Rollup of 10 pull requests
Successful merges:
- #92611 (Add links to the reference and rust by example for asm! docs and lints)
- #93158 (wasi: implement `sock_accept` and enable networking)
- #93239 (Add os::unix::net::SocketAddr::from_path)
- #93261 (Some unwinding related cg_ssa cleanups)
- #93295 (Avoid double panics when using `TempDir` in tests)
- #93353 (Unimpl {Add,Sub,Mul,Div,Rem,BitXor,BitOr,BitAnd}<$t> for Saturating<$t>)
- #93356 (Edit docs introduction for `std::cmp::PartialOrd`)
- #93375 (fix typo `documenation`)
- #93399 (rustbuild: Fix compiletest warning when building outside of root.)
- #93404 (Fix a typo from #92899)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Fix debuginfo for pointers/references to unsized types
This PR makes the compiler emit fat pointer debuginfo in all cases. Before, we sometimes got thin-pointer debuginfo, making it impossible to fully interpret the pointed to memory in debuggers. The code is actually cleaner now, especially around generation of trait object pointer debuginfo.
Fixes https://github.com/rust-lang/rust/issues/92718
~~Blocked on https://github.com/rust-lang/rust/pull/92729.~~
LLDB does not seem to see fields if they are marked with DW_AT_artificial
which breaks pretty printers that use these fields for decoding fat pointers.
Use error-on-mismatch policy for PAuth module flags.
This agrees with Clang, and avoids an error when using LTO with mixed
C/Rust. LLVM considers different behaviour flags to be a mismatch,
even when the flag value itself is the same.
This also makes the flag setting explicit for all uses of
LLVMRustAddModuleFlag.
----
I believe that this fixes#92885, but have only reproduced it locally on Linux hosts so cannot confirm that it fixes the issue as reported.
I have not included a test for this because it is covered by an existing test (`src/test/run-make-fulldeps/cross-lang-lto-clang`). It is not without its problems, though:
* The test requires Clang and `--run-clang-based-tests-with=...` to run, and this is not the case on the CI.
* Any test I add would have a similar requirement.
* With this patch applied, the test gets further, but it still fails (for other reasons). I don't think that affects #92885.
Work around missing code coverage data causing llvm-cov failures
If we do not add code coverage instrumentation to the `Body` of a
function, then when we go to generate the function record for it, we
won't write any data and this later causes llvm-cov to fail when
processing data for the entire coverage report.
I've identified two main cases where we do not currently add code
coverage instrumentation to the `Body` of a function:
1. If the function has a single `BasicBlock` and it ends with a
`TerminatorKind::Unreachable`.
2. If the function is created using a proc macro of some kind.
For case 1, this is typically not important as this most often occurs as
a result of function definitions that take or return uninhabited
types. These kinds of functions, by definition, cannot even be called so
they logically should not be counted in code coverage statistics.
For case 2, I haven't looked into this very much but I've noticed while
testing this patch that (other than functions which are covered by case
1) the skipped function coverage debug message is occasionally triggered
in large crate graphs by functions generated from a proc macro. This may
have something to do with weird spans being generated by the proc macro
but this is just a guess.
I think it's reasonable to land this change since currently, we fail to
generate *any* results from llvm-cov when a function has no coverage
instrumentation applied to it. With this change, we get coverage data
for all functions other than the two cases discussed above.
Fixes#93054 which occurs because of uncallable functions which shouldn't
have code coverage anyway.
I will open an issue for missing code coverage of proc macro generated
functions and leave a link here once I have a more minimal repro.
r? ``@tmandry``
cc ``@richkadel``
This agrees with Clang, and avoids an error when using LTO with mixed
C/Rust. LLVM considers different behaviour flags to be a mismatch,
even when the flag value itself is the same.
This also makes the flag setting explicit for all uses of
LLVMRustAddModuleFlag.
If we do not add code coverage instrumentation to the `Body` of a
function, then when we go to generate the function record for it, we
won't write any data and this later causes llvm-cov to fail when
processing data for the entire coverage report.
I've identified two main cases where we do not currently add code
coverage instrumentation to the `Body` of a function:
1. If the function has a single `BasicBlock` and it ends with a
`TerminatorKind::Unreachable`.
2. If the function is created using a proc macro of some kind.
For case 1, this typically not important as this most often occurs as
the result of function definitions that take or return uninhabited
types. These kinds of functions, by definition, cannot even be called so
they logically should not be counted in code coverage statistics.
For case 2, I haven't looked into this very much but I've noticed while
testing this patch that (other than functions which are covered by case
1) the skipped function coverage debug message is occasionally triggered
in large crate graphs by functions generated from a proc macro. This may
have something to do with weird spans being generated by the proc macro
but this is just a guess.
I think it's reasonable to land this change since currently, we fail to
generate *any* results from llvm-cov when a function has no coverage
instrumentation applied to it. With this change, we get coverage data
for all functions other than the two cases discussed above.
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`
Implement raw-dylib support for windows-gnu
Add support for `#[link(kind = "raw-dylib")]` on windows-gnu targets. Work around binutils's linker's inability to read import libraries produced by LLVM by calling out to the binutils `dlltool` utility to create an import library from a temporary .DEF file; this approach is effectively a slightly refined version of `@mati865's` earlier attempt at this strategy in PR #88801. (In particular, this attempt at this strategy adds support for `#[link_ordinal(...)]` as well.)
In support of #58713.
Avoid unnecessary monomorphization of inline asm related functions
This should reduce build time for codegen backends by avoiding duplicated monomorphization of certain inline asm related functions for each passed in closure type.
Remove LLVMRustMarkAllFunctionsNounwind
This was originally introduced in #10916 as a way to remove all landing
pads when performing LTO. However this is no longer necessary today
since rustc properly marks all functions and call-sites as nounwind
where appropriate.
In fact this is incorrect in the presence of `extern "C-unwind"` which
must create a landing pad when compiled with `-C panic=abort` so that
foreign exceptions are caught and properly turned into aborts.
Remove deprecated LLVM-style inline assembly
The `llvm_asm!` was deprecated back in #87590 1.56.0, with intention to remove
it once `asm!` was stabilized, which already happened in #91728 1.59.0. Now it
is time to remove `llvm_asm!` to avoid continued maintenance cost.
Closes#70173.
Closes#92794.
Closes#87612.
Closes#82065.
cc `@rust-lang/wg-inline-asm`
r? `@Amanieu`
This was originally introduced in #10916 as a way to remove all landing
pads when performing LTO. However this is no longer necessary today
since rustc properly marks all functions and call-sites as nounwind
where appropriate.
In fact this is incorrect in the presence of `extern "C-unwind"` which
must create a landing pad when compiled with `-C panic=abort` so that
foreign exceptions are caught and properly turned into aborts.
[code coverage] Fix missing dead code in modules that are never called
The issue here is that the logic used to determine which CGU to put the dead function stubs in doesn't handle cases where a module is never assigned to a CGU (which is what happens when all of the code in the module is dead).
The partitioning logic also caused issues in #85461 where inline functions were duplicated into multiple CGUs resulting in duplicate symbols.
This commit fixes the issue by removing the complex logic used to assign dead code stubs to CGUs and replaces it with a much simpler model: we pick one CGU to hold all the dead code stubs. We pick a CGU which has exported items which increases the likelihood the linker won't throw away our dead functions and we pick the smallest to minimize the impact on compilation times for crates with very large CGUs.
Fixes#91661Fixes#86177Fixes#85718Fixes#79622
r? ```@tmandry```
cc ```@richkadel```
This PR is not urgent so please don't let it interrupt your holidays! 🎄🎁
