cg_llvm: Use a type-safe helper to cast `&str` and `&[u8]` to `*const c_char`
In `rustc_codegen_llvm` there are many uses of `.as_ptr().cast()` to convert a string or byte-slice to `*const c_char`, which then gets passed through FFI.
This works, but is fragile, because there's nothing constraining the pointer cast to actually be from `u8` to `c_char`. If the original value changes to something else that has an `as_ptr` method, or the context changes to expect something other than `c_char`, the cast will silently do the wrong thing.
By making the cast more explicit via a helper method, we can be sure that it will either perform the intended cast, or fail at compile time.
This commit adds a new rustc target feature named `wide-arithmetic` for
WebAssembly targets. This corresponds to the [wide-arithmetic] proposal
for WebAssembly which adds new instructions catered towards accelerating
integer arithmetic larger than 64-bits. This proposal to WebAssembly is
not standard yet so this new feature is flagged as an unstable target
feature. Additionally Rust's LLVM version doesn't support this new
feature yet since support will first be added in LLVM 20, so the
feature filtering logic for LLVM is updated to handle this.
I'll also note that I'm not currently planning to add wasm-specific
intrinsics to `std::arch::wasm32` at this time. The currently proposed
instructions are all accessible through `i128` or `u128`-based
operations which Rust already supports, so intrinsic shouldn't be
necessary to get access to these new instructions.
[wide-arithmetic]: https://github.com/WebAssembly/wide-arithmetic
Replace some LLVMRust wrappers with calls to the LLVM C API
This PR removes the LLVMRust wrapper functions for getting/setting linkage and visibility, and replaces them with direct calls to the corresponding functions in LLVM's C API.
To make this convenient and sound, two pieces of supporting code have also been added:
- A simple proc-macro that derives `TryFrom<u32>` for fieldless enums
- A wrapper type for C enum values returned by LLVM functions, to ensure soundness if LLVM returns an enum value we don't know about
In a few places, the use of safe wrapper functions means that an `unsafe` block is no longer needed, so the affected code has changed its indentation level.
rustc_target: Add pauth-lr aarch64 target feature
Add the pauth-lr target feature, corresponding to aarch64 FEAT_PAuth_LR. This feature has been added in LLVM 19.
It is currently not supported by the Linux hwcap and so we cannot add runtime feature detection for it at this time.
r? `@Amanieu`
coverage: Consolidate creation of covmap/covfun records
This code for creating covmap/covfun records during codegen was split across multiple functions and files for dubious historical reasons. Having it all in one place makes it easier to follow.
This PR also includes two semi-related cleanups:
- Getting the codegen context's `coverage_cx` state is made infallible, since it should always exist when running the code paths that need it.
- The value of `covfun_section_name` is saved in the codegen context, since it never changes at runtime, and the code that needs it has access to the context anyway.
---
Background: Coverage instrumentation generates two kinds of metadata that are embedded in the final binary. There is per-CGU information that goes in the `__llvm_covmap` linker section, and per-function information that goes in the `__llvm_covfun` section (except on Windows, where slightly different section names are used).
- removed extra bits from predicates queries that are no longer needed in the new system
- removed the need for `non_erasable_generics` to take in tcx and DefId, removed unused arguments in callers
Adding an extra `OnceCell` to `CrateCoverageContext` is much nicer than trying
to thread this string through multiple layers of function calls that already
have access to the context.
coverage: Pass coverage mappings to LLVM as separate structs
Instead of trying to cram *N* different kinds of coverage mapping data into a single list for FFI, pass *N* different lists of simpler structs.
This avoids the need to fill unused fields with dummy values, and avoids the need to tag structs with their underlying kind. It also lets us call the dedicated LLVM constructors for each different mapping type, instead of having to go through the complex general-purpose constructor.
Even though this adds multiple new structs to the FFI surface area, the resulting C++ code is simpler and shorter.
---
I've structured this mostly as a single atomic patch, rather than a series of incremental changes, because that avoids the need to make fiddly fixes to code that is about to be deleted anyway.
Continue to get rid of `ty::Const::{try_}eval*`
This PR mostly does:
* Removes all of the `try_eval_*` and `eval_*` helpers from `ty::Const`, and replace their usages with `try_to_*`.
* Remove `ty::Const::eval`.
* Rename `ty::Const::normalize` to `ty::Const::normalize_internal`. This function is still used in the normalization code itself.
* Fix some weirdness around the `TransmuteFrom` goal.
I'm happy to split it out further; for example, I could probably land the first part which removes the helpers, or the changes to codegen which are more obvious than the changes to tools.
r? BoxyUwU
Part of https://github.com/rust-lang/rust/issues/130704
Migrate `llvm::set_comdat` and `llvm::SetUniqueComdat` to LLVM-C FFI.
Note, now we can call `llvm::set_comdat` only when the target actually
supports adding comdat. As this has no convenient LLVM-C API, we
implement this as `TargetOptions::supports_comdat`.
Co-authored-by: Stuart Cook <Zalathar@users.noreply.github.com>
Add the pauth-lr target feature, corresponding to aarch64 FEAT_PAuth_LR.
This feature has been added in LLVM 19.
It is currently not supported by the Linux hwcap and so we cannot add
runtime feature detection for it at this time.
LLVM has added 3 new address spaces to support special Windows use
cases. These shouldn't trouble us for now, but LLVM requires matching
data layouts.
See llvm/llvm-project#111879 for details
intrinsics fmuladdf{32,64}: expose llvm.fmuladd.* semantics
Add intrinsics `fmuladd{f32,f64}`. This computes `(a * b) + c`, to be fused if the code generator determines that (i) the target instruction set has support for a fused operation, and (ii) that the fused operation is more efficient than the equivalent, separate pair of `mul` and `add` instructions.
https://llvm.org/docs/LangRef.html#llvm-fmuladd-intrinsic
The codegen_cranelift uses the `fma` function from libc, which is a correct implementation, but without the desired performance semantic. I think this requires an update to cranelift to expose a suitable instruction in its IR.
I have not tested with codegen_gcc, but it should behave the same way (using `fma` from libc).
---
This topic has been discussed a few times on Zulip and was suggested, for example, by `@workingjubilee` in [Effect of fma disabled](https://rust-lang.zulipchat.com/#narrow/stream/122651-general/topic/Effect.20of.20fma.20disabled/near/274179331).
Add intrinsics `fmuladd{f16,f32,f64,f128}`. This computes `(a * b) +
c`, to be fused if the code generator determines that (i) the target
instruction set has support for a fused operation, and (ii) that the
fused operation is more efficient than the equivalent, separate pair
of `mul` and `add` instructions.
https://llvm.org/docs/LangRef.html#llvm-fmuladd-intrinsic
MIRI support is included for f32 and f64.
The codegen_cranelift uses the `fma` function from libc, which is a
correct implementation, but without the desired performance semantic. I
think this requires an update to cranelift to expose a suitable
instruction in its IR.
I have not tested with codegen_gcc, but it should behave the same
way (using `fma` from libc).
Use Default visibility for rustc-generated C symbol declarations
Non-default visibilities should only be used for definitions, not declarations, otherwise linking can fail.
This is based on https://github.com/rust-lang/rust/pull/123994.
Issue https://github.com/rust-lang/rust/issues/123427
When I changed `default-hidden-visibility` to `default-visibility` in https://github.com/rust-lang/rust/pull/130005, I updated all places in the code that used `default-hidden-visibility`, replicating the hidden-visibility bug to also happen for protected visibility.
Without this change, trying to build rustc with `-Z default-visibility=protected` fails with a link error.
Non-default visibilities should only be used for definitions, not
declarations, otherwise linking can fail.
Co-authored-by: Collin Baker <collinbaker@chromium.org>
rustc_target: Add sme-b16b16 as an explicit aarch64 target feature
LLVM 20 split out what used to be called b16b16 and correspond to aarch64
FEAT_SVE_B16B16 into sve-b16b16 and sme-b16b16.
Add sme-b16b16 as an explicit feature and update the codegen accordingly.
Resolves https://github.com/rust-lang/rust/pull/129894.
codegen_ssa: consolidate tied target checks
Fixes#105110.
Fixes#105111.
`rustc_codegen_llvm` and `rustc_codegen_gcc` duplicated logic for checking if tied target features were partially enabled. This PR consolidates these checks into `rustc_codegen_ssa` in the `codegen_fn_attrs` query, which also is run pre-monomorphisation for each function, which ensures that this check is run for unused functions, as would be expected.
Also adds a test confirming that enabling one tied feature doesn't imply another - the appropriate error for this was already being emitted. I did a bisect and narrowed it down to two patches it was likely to be - something in #128796, probably #128221 or #128679.
LLVM 20 split out what used to be called b16b16 and correspond to aarch64
FEAT_SVE_B16B16 into sve-b16b16 and sme-b16b16.
Add sme-b16b16 as an explicit feature and update the codegen accordingly.
compiler: Stop reexporting enum-globs from `rustc_target::abi`
Three enums had **all** their variants glob-exported into a distressingly large amount of the tree. Cease to do that, and also cease to glob import the contents of the module that contained them. Redirect relevant imports to their actual source, the `rustc_abi` crate.
No functional changes.
[Coverage][MCDC] Adapt mcdc to llvm 19
Related issue: #126672
Also finish task 4 at #124144
[llvm #82448](https://github.com/llvm/llvm-project/pull/82448) has introduced some break changes into mcdc, causing incompatibility between llvm 18 and 19. This draft adapts to that change and gives up supporting for llvm-18.
Add missing module flags for `-Zfunction-return=thunk-extern`
This fixes a bug in the `-Zfunction-return=thunk-extern` flag. The flag needs to be passed onto LLVM to ensure that functions such as `asan.module_ctor` and `asan.module_dtor` that are created internally in LLVM have the mitigation applied to them.
This was originally discovered [in the Linux kernel](https://lore.kernel.org/all/CANiq72myZL4_poCMuNFevtpYYc0V0embjSuKb7y=C+m3vVA_8g@mail.gmail.com/).
Original flag PR: #116892
PR for similar issue: #129373
Tracking issue: #116853
cc ``@ojeda``
r? ``@wesleywiser``
Like #130865 did for the standard library, we can use `&raw` in the
compiler now that stage0 supports it. Also like the other issue, I did
not make any doc or test changes at this time.
`rustc_codegen_llvm` and `rustc_codegen_gcc` duplicated logic for
checking if tied target features were partially enabled. This commit
consolidates these checks into `rustc_codegen_ssa` in the
`codegen_fn_attrs` query, which also is run pre-monomorphisation for
each function, which ensures that this check is run for unused functions,
as would be expected.
llvm: replace some deprecated functions
`LLVMMDStringInContext` and `LLVMMDNodeInContext` are deprecated, replace them with `LLVMMDStringInContext2` and `LLVMMDNodeInContext2`.
Also replace `Value` with `Metadata` in some function signatures for better consistency.
Bump stage0 to beta-2024-09-22 and rustfmt to nightly-2024-09-22
I'm doing this to apply the changes to version sorting (https://github.com/rust-lang/rustfmt/pull/6284) that have occurred since rustfmt last upgraded (and a few other miscellaneous changes, like changes to expression overflowing: https://github.com/rust-lang/rustfmt/pull/6260). Eagerly updating rustfmt and formatting-the-world will ideally move some of the pressure off of the beta bump which will happen at the beginning of the next release cycle.
You can verify this is correct by checking out the changes, reverting the last commit, reapplying them, and diffing the changes:
```
git fetch git@github.com:compiler-errors/rust.git bump
git checkout -b bump FETCH_HEAD
git reset --hard HEAD~5
./x.py fmt --all
git diff FETCH_HEAD
# ignore the changes to stage0, and rustfmt.toml,
# and test file changes in rustdoc-js-std, run-make.
```
Or just take my word for it? Up to the reviewer.
r? release
Remove macOS 10.10 dynamic linker bug workaround
Rust's current minimum macOS version is 10.12, so the hack can be removed. This PR also updates the `remove_dir_all` docs to reflect that all supported macOS versions are protected against TOCTOU race conditions (the fallback implementation was already removed in #127683).
try-job: dist-x86_64-apple
try-job: dist-aarch64-apple
try-job: dist-apple-various
try-job: aarch64-apple
try-job: x86_64-apple-1
It's crazy to have the integer methods in something close to random
order.
The reordering makes the gaps clear: `const_i64`, `const_i128`,
`const_isize`, and `const_u16`. I guess they just aren't needed.
In `get_fn` there is a complicated set of if/elses to determine if
`hidden` visibility should be applied. There are five calls to
`LLVMRustSetVisibility` and some repetition in the comments.
This commit streamlines it a bit:
- Computes `hidden` and then uses it to determine if a single call to
`LLVMRustSetVisibility` occurs.
- Converts some of the if/elses into boolean expressions.
- Removes the repetitive comments.
Overall this makes it quite a bit shorter, and I find it easier to read.
Supertraits of `BuilderMethods` are all called `XyzBuilderMethods`.
Supertraits of `CodegenMethods` are all called `XyzMethods`. This commit
changes the latter to `XyzCodegenMethods`, for consistency.
It has `Backend` and `Deref` boudns, plus an associated type
`CodegenCx`, and it has a single use. This commit "inlines" it into
`BuilderMethods`, which makes the complicated backend trait situation a
little simpler.
Use -0.0 in `intrinsics::simd::reduce_add_unordered`
-0.0 is the actual neutral additive float, not +0.0, and this matters to codegen.
try-job: aarch64-gnu
deprecate -Csoft-float because it is unsound (and not fixable)
See https://github.com/rust-lang/rust/issues/129893 for details. The general sentiment there seems to be that this flag has no use and sound alternatives exist, so let's add this warning and see if anyone out there disagrees.
Also show a different warning on targets where it does nothing (as documented since https://github.com/rust-lang/rust/pull/36261): it seems to correspond to `-mfloat-abi` in GCC/clang, which is an ARM-specific option. To be really sure it does nothing, only forward the flag to LLVM for eabihf targets. This should not change behavior but makes me sleep better ;)
Don't leave debug locations for constants sitting on the builder indefinitely
Because constants are currently emitted *before* the prologue, leaving the debug location on the IRBuilder spills onto other instructions in the prologue and messes up both line numbers as well as the point LLVM chooses to be the prologue end.
Example LLVM IR (irrelevant IR elided):
Before:
```
define internal { i64, i64 } `@_ZN3tmp3Foo18var_return_opt_try17he02116165b0fc08cE(ptr` align 8 %self) !dbg !347 { start:
%self.dbg.spill = alloca [8 x i8], align 8
%_0 = alloca [16 x i8], align 8
%residual.dbg.spill = alloca [0 x i8], align 1
#dbg_declare(ptr %residual.dbg.spill, !353, !DIExpression(), !357)
store ptr %self, ptr %self.dbg.spill, align 8, !dbg !357
#dbg_declare(ptr %self.dbg.spill, !350, !DIExpression(), !358)
```
After:
```
define internal { i64, i64 } `@_ZN3tmp3Foo18var_return_opt_try17h00b17d08874ddd90E(ptr` align 8 %self) !dbg !347 { start:
%self.dbg.spill = alloca [8 x i8], align 8
%_0 = alloca [16 x i8], align 8
%residual.dbg.spill = alloca [0 x i8], align 1
#dbg_declare(ptr %residual.dbg.spill, !353, !DIExpression(), !357)
store ptr %self, ptr %self.dbg.spill, align 8
#dbg_declare(ptr %self.dbg.spill, !350, !DIExpression(), !358)
```
Note in particular how !357 from %residual.dbg.spill's dbg_declare no longer falls through onto the store to %self.dbg.spill. This fixes argument values at entry when the constant is a ZST (e.g. `<Option as Try>::Residual`). This fixes#130003 (but note that it does *not* fix issues with argument values and non-ZST constants, which emit their own stores that have debug info on them, like #128945).
r? `@michaelwoerister`
Simplify some nested `if` statements
Applies some but not all instances of `clippy::collapsible_if`. Some ended up looking worse afterwards, though, so I left those out. Also applies instances of `clippy::collapsible_else_if`
Review with whitespace disabled please.
Add -Z small-data-threshold
This flag allows specifying the threshold size above which LLVM should not consider placing small objects in a `.sdata` or `.sbss` section.
Support is indicated in the target options via the
small-data-threshold-support target option, which can indicate either an
LLVM argument or an LLVM module flag. To avoid duplicate specifications
in a large number of targets, the default value for support is
DefaultForArch, which is translated to a concrete value according to the
target's architecture.
This flag allows specifying the threshold size above which LLVM should
not consider placing small objects in a .sdata or .sbss section.
Support is indicated in the target options via the
small-data-threshold-support target option, which can indicate either an
LLVM argument or an LLVM module flag. To avoid duplicate specifications
in a large number of targets, the default value for support is
DefaultForArch, which is translated to a concrete value according to the
target's architecture.
s390x: Fix a regression related to backchain feature
In #127506, we introduced a new IBM Z-specific target feature, `backchain`.
This particular `target-feature` was available as a function-level attribute in LLVM 17 and below, so some hacks were used to avoid blowing up LLVM when querying the supported LLVM features.
This led to an unfortunate regression where `cfg!(target-feature = "backchain")` will always return true.
This pull request aims to fix this issue, and a test has been introduced to ensure it will never happen again.
Fixes#129927.
r? `@RalfJung`
Do not request sanitizers for naked functions
Naked functions can only contain inline asm, so any instrumentation inserted by sanitizers is illegal. Don't request it.
Fixes https://github.com/rust-lang/rust/issues/129224.
Because constants are currently emitted *before* the prologue, leaving the
debug location on the IRBuilder spills onto other instructions in the prologue
and messes up both line numbers as well as the point LLVM chooses to be the
prologue end.
Example LLVM IR (irrelevant IR elided):
Before:
define internal { i64, i64 } @_ZN3tmp3Foo18var_return_opt_try17he02116165b0fc08cE(ptr align 8 %self) !dbg !347 {
start:
%self.dbg.spill = alloca [8 x i8], align 8
%_0 = alloca [16 x i8], align 8
%residual.dbg.spill = alloca [0 x i8], align 1
#dbg_declare(ptr %residual.dbg.spill, !353, !DIExpression(), !357)
store ptr %self, ptr %self.dbg.spill, align 8, !dbg !357
#dbg_declare(ptr %self.dbg.spill, !350, !DIExpression(), !358)
After:
define internal { i64, i64 } @_ZN3tmp3Foo18var_return_opt_try17h00b17d08874ddd90E(ptr align 8 %self) !dbg !347 {
start:
%self.dbg.spill = alloca [8 x i8], align 8
%_0 = alloca [16 x i8], align 8
%residual.dbg.spill = alloca [0 x i8], align 1
#dbg_declare(ptr %residual.dbg.spill, !353, !DIExpression(), !357)
store ptr %self, ptr %self.dbg.spill, align 8
#dbg_declare(ptr %self.dbg.spill, !350, !DIExpression(), !358)
Note in particular how !357 from %residual.dbg.spill's dbg_declare no longer
falls through onto the store to %self.dbg.spill. This fixes argument values
at entry when the constant is a ZST (e.g. <Option as Try>::Residual). This
fixes#130003 (but note that it does *not* fix issues with argument values and
non-ZST constants, which emit their own stores that have debug info on them,
like #128945).
Make `Ty::boxed_ty` return an `Option`
Looks like a good place to use Rust's type system.
---
Most of 4ac7bcbaad/compiler/rustc_middle/src/ty/sty.rs (L971-L1963) looks like it could be moved to `TyKind` (then I guess `Ty` should be made to deref to `TyKind`).
Don't emit `expect`/`assume` in opt-level=0
LLVM does not make use of expect/assume calls in `opt-level=0`, so we can simplify IR by not emitting them in this case.
rustc_target: Add various aarch64 features
Add various aarch64 features already supported by LLVM and Linux.
Additionally include some comment fixes to ensure consistency of feature names with the Arm ARM.
Compiler support for features added to stdarch by https://github.com/rust-lang/stdarch/pull/1614.
Tracking issue for unstable aarch64 features is https://github.com/rust-lang/rust/issues/127764.
List of added features:
- FEAT_CSSC
- FEAT_ECV
- FEAT_FAMINMAX
- FEAT_FLAGM2
- FEAT_FP8
- FEAT_FP8DOT2
- FEAT_FP8DOT4
- FEAT_FP8FMA
- FEAT_HBC
- FEAT_LSE128
- FEAT_LSE2
- FEAT_LUT
- FEAT_MOPS
- FEAT_LRCPC3
- FEAT_SVE_B16B16
- FEAT_SVE2p1
- FEAT_WFxT
- FEAT_SME
- FEAT_SME_F16F16
- FEAT_SME_F64F64
- FEAT_SME_F8F16
- FEAT_SME_F8F32
- FEAT_SME_FA64
- FEAT_SME_I16I64
- FEAT_SME_LUTv2
- FEAT_SME2
- FEAT_SME2p1
- FEAT_SSVE_FP8DOT2
- FEAT_SSVE_FP8DOT4
- FEAT_SSVE_FP8FMA
FEAT_FPMR is added in the first commit and then removed in a separate one to highlight it being removed from upstream LLVM 19. The intention is for it to be detectable at runtime through stdarch but not have a corresponding Rust compile-time feature.
LLVM uses the word "code" to refer to a particular kind of coverage mapping.
This unrelated usage of the word is confusing, and makes it harder to introduce
types whose names correspond to the LLVM classification of coverage kinds.
Convert to_llvm_features to return Option<LLVMFeature> so that it can
return None if the requested feature is not available for the current
LLVM version.
Add match rules to filter out aarch64 features not available in LLVM 17.
FEAT_FPMR has been removed from upstream LLVM as of LLVM 19.
Remove the feature from the target features list and temporarily hack
the LLVM codegen to always enable it until the minimum LLVM version is
bumped to 19.
Add various aarch64 features already supported by LLVM and Linux.
The features are marked as unstable using a newly added symbol, i.e.
aarch64_unstable_target_feature.
Additionally include some comment fixes to ensure consistency of
feature names with the Arm ARM and support for architecture version
target features up to v9.5a.
This commit adds compiler support for the following features:
- FEAT_CSSC
- FEAT_ECV
- FEAT_FAMINMAX
- FEAT_FLAGM2
- FEAT_FP8
- FEAT_FP8DOT2
- FEAT_FP8DOT4
- FEAT_FP8FMA
- FEAT_FPMR
- FEAT_HBC
- FEAT_LSE128
- FEAT_LSE2
- FEAT_LUT
- FEAT_MOPS
- FEAT_LRCPC3
- FEAT_SVE_B16B16
- FEAT_SVE2p1
- FEAT_WFxT
Add `f16` and `f128` inline ASM support for `aarch64`
Adds `f16` and `f128` inline ASM support for `aarch64`. SIMD vector types are taken from [the ARM intrinsics list](https://developer.arm.com/architectures/instruction-sets/intrinsics/#f:`@navigationhierarchiesreturnbasetype=[float]&f:@navigationhierarchieselementbitsize=[16]&f:@navigationhierarchiesarchitectures=[A64]).` Based on the work of `@lengrongfu` in #127043.
Relevant issue: #125398
Tracking issue: #116909
`@rustbot` label +F-f16_and_f128
try-job: aarch64-gnu
try-job: aarch64-apple
simd_shuffle intrinsic: allow argument to be passed as vector
See https://github.com/rust-lang/rust/issues/128738 for context.
I'd like to get rid of [this hack](6c0b89dfac/compiler/rustc_codegen_ssa/src/mir/block.rs (L922-L935)). https://github.com/rust-lang/rust/pull/128537 almost lets us do that since constant SIMD vectors will then be passed as immediate arguments. However, simd_shuffle for some reason actually takes an *array* as argument, not a vector, so the hack is still required to ensure that the array becomes an immediate (which then later stages of codegen convert into a vector, as that's what LLVM needs).
This PR prepares simd_shuffle to also support a vector as the `idx` argument. Once this lands, stdarch can hopefully be updated to pass `idx` as a vector, and then support for arrays can be removed, which finally lets us get rid of that hack.
Add `#[warn(unreachable_pub)]` to a bunch of compiler crates
By default `unreachable_pub` identifies things that need not be `pub` and tells you to make them `pub(crate)`. But sometimes those things don't need any kind of visibility. So they way I did these was to remove the visibility entirely for each thing the lint identifies, and then add `pub(crate)` back in everywhere the compiler said it was necessary. (Or occasionally `pub(super)` when context suggested that was appropriate.) Tedious, but results in more `pub` removal.
There are plenty more crates to do but this seems like enough for a first PR.
r? `@compiler-errors`
Set the cfi-normalize-integers and kcfi-offset module flags when
Control-Flow Integrity sanitizers are used, so functions generated by
the LLVM backend use the same CFI/KCFI options as rustc.
cfi-normalize-integers tells LLVM to also use integer normalization
for generated functions when -Zsanitizer-cfi-normalize-integers is
used.
kcfi-offset specifies the number of prefix nops between the KCFI
type hash and the function entry when -Z patchable-function-entry is
used. Note that LLVM assumes all indirectly callable functions use the
same number of prefix NOPs with -Zsanitizer=kcfi.
Avoid extra `cast()`s after `CStr::as_ptr()`
These used to be `&str` literals that did need a pointer cast, but that
became a no-op after switching to `c""` literals in #118566.
Special case DUMMY_SP to emit line 0/column 0 locations on DWARF platforms.
Line 0 has a special meaning in DWARF. From the version 5 spec:
The compiler may emit the value 0 in cases
where an instruction cannot be attributed to any
source line.
DUMMY_SP spans cannot be attributed to any line. However, because rustc internally stores line numbers starting at zero, lookup_debug_loc() adjusts every line number by one. Special casing DUMMY_SP to actually emit line 0 ensures rustc communicates to the debugger that there's no meaningful source code for this instruction, rather than telling the debugger to jump to line 1 randomly.
With the new resolver, a few dependencies get brought in twice with
different licenses. For example, all dependencies from `wasm-tools`
gained Apache-2.0 and MIT options, and with the v2 resolver we were
using one version from before and one version from after this change.
This made tidy's license check difficult.
Update some minimum versions to remove duplicate dependencies and smooth
out license checking.
Fix `is_val_statically_known` for floats
The LLVM intrinsic name for floats differs from the LLVM type name, so handle them explicitly. Also adds support for `f16` and `f128`.
`f16`/`f128` tracking issue: #116909
Rework MIR inlining debuginfo so function parameters show up in debuggers.
Line numbers of multiply-inlined functions were fixed in #114643 by using a single DISubprogram. That, however, triggered assertions because parameters weren't deduplicated. The "solution" to that in #115417 was to insert a DILexicalScope below the DISubprogram and parent all of the parameters to that scope. That fixed the assertion, but debuggers (including gdb and lldb) don't recognize variables that are not parented to the subprogram itself as parameters, even if they are emitted with DW_TAG_formal_parameter.
Consider the program:
```rust
use std::env;
#[inline(always)]
fn square(n: i32) -> i32 {
n * n
}
#[inline(never)]
fn square_no_inline(n: i32) -> i32 {
n * n
}
fn main() {
let x = square(env::vars().count() as i32);
let y = square_no_inline(env::vars().count() as i32);
println!("{x} == {y}");
}
```
When making a release build with debug=2 and rustc 1.82.0-nightly (8b3870784 2024-08-07)
```
(gdb) r
Starting program: /ephemeral/tmp/target/release/tmp [Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Breakpoint 1, tmp::square () at src/main.rs:5
5 n * n
(gdb) info args
No arguments.
(gdb) info locals
n = 31
(gdb) c
Continuing.
Breakpoint 2, tmp::square_no_inline (n=31) at src/main.rs:10
10 n * n
(gdb) info args
n = 31
(gdb) info locals
No locals.
```
This issue is particularly annoying because it removes arguments from stack traces.
The DWARF for the inlined function looks like this:
```
< 2><0x00002132 GOFF=0x00002132> DW_TAG_subprogram
DW_AT_linkage_name _ZN3tmp6square17hc507052ff3d2a488E
DW_AT_name square
DW_AT_decl_file 0x0000000f /ephemeral/tmp/src/main.rs
DW_AT_decl_line 0x00000004
DW_AT_type 0x00001a56<.debug_info+0x00001a56>
DW_AT_inline DW_INL_inlined
< 3><0x00002142 GOFF=0x00002142> DW_TAG_lexical_block
< 4><0x00002143 GOFF=0x00002143> DW_TAG_formal_parameter
DW_AT_name n
DW_AT_decl_file 0x0000000f /ephemeral/tmp/src/main.rs
DW_AT_decl_line 0x00000004
DW_AT_type 0x00001a56<.debug_info+0x00001a56>
< 4><0x0000214e GOFF=0x0000214e> DW_TAG_null
< 3><0x0000214f GOFF=0x0000214f> DW_TAG_null
```
That DW_TAG_lexical_block inhibits every debugger I've tested from recognizing 'n' as a parameter.
This patch removes the additional lexical scope. Parameters can be easily deduplicated by a tuple of their scope and the argument index, at the trivial cost of taking a Hash + Eq bound on DIScope.
Use the `enum2$` Natvis visualiser for repr128 C-style enums
Use the preexisting `enum2$` Natvis visualiser to allow PDB debuggers to display fieldless `#[repr(u128)]]`/`#[repr(i128)]]` enums correctly.
Tracking issue: #56071
try-job: x86_64-msvc
Shrink `TyKind::FnPtr`.
By splitting the `FnSig` within `TyKind::FnPtr` into `FnSigTys` and `FnHeader`, which can be packed more efficiently. This reduces the size of the hot `TyKind` type from 32 bytes to 24 bytes on 64-bit platforms. This reduces peak memory usage by a few percent on some benchmarks. It also reduces cache misses and page faults similarly, though this doesn't translate to clear cycles or wall-time improvements on CI.
r? `@compiler-errors`
Line numbers of multiply-inlined functions were fixed in #114643 by using a
single DISubprogram. That, however, triggered assertions because parameters
weren't deduplicated. The "solution" to that in #115417 was to insert a
DILexicalScope below the DISubprogram and parent all of the parameters to that
scope. That fixed the assertion, but debuggers (including gdb and lldb) don't
recognize variables that are not parented to the subprogram itself as parameters,
even if they are emitted with DW_TAG_formal_parameter.
Consider the program:
use std::env;
fn square(n: i32) -> i32 {
n * n
}
fn square_no_inline(n: i32) -> i32 {
n * n
}
fn main() {
let x = square(env::vars().count() as i32);
let y = square_no_inline(env::vars().count() as i32);
println!("{x} == {y}");
}
When making a release build with debug=2 and rustc 1.82.0-nightly (8b3870784 2024-08-07)
(gdb) r
Starting program: /ephemeral/tmp/target/release/tmp
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Breakpoint 1, tmp::square () at src/main.rs:5
5 n * n
(gdb) info args
No arguments.
(gdb) info locals
n = 31
(gdb) c
Continuing.
Breakpoint 2, tmp::square_no_inline (n=31) at src/main.rs:10
10 n * n
(gdb) info args
n = 31
(gdb) info locals
No locals.
This issue is particularly annoying because it removes arguments from stack traces.
The DWARF for the inlined function looks like this:
< 2><0x00002132 GOFF=0x00002132> DW_TAG_subprogram
DW_AT_linkage_name _ZN3tmp6square17hc507052ff3d2a488E
DW_AT_name square
DW_AT_decl_file 0x0000000f /ephemeral/tmp/src/main.rs
DW_AT_decl_line 0x00000004
DW_AT_type 0x00001a56<.debug_info+0x00001a56>
DW_AT_inline DW_INL_inlined
< 3><0x00002142 GOFF=0x00002142> DW_TAG_lexical_block
< 4><0x00002143 GOFF=0x00002143> DW_TAG_formal_parameter
DW_AT_name n
DW_AT_decl_file 0x0000000f /ephemeral/tmp/src/main.rs
DW_AT_decl_line 0x00000004
DW_AT_type 0x00001a56<.debug_info+0x00001a56>
< 4><0x0000214e GOFF=0x0000214e> DW_TAG_null
< 3><0x0000214f GOFF=0x0000214f> DW_TAG_null
That DW_TAG_lexical_block inhibits every debugger I've tested from recognizing
'n' as a parameter.
This patch removes the additional lexical scope. Parameters can be easily
deduplicated by a tuple of their scope and the argument index, at the trivial
cost of taking a Hash + Eq bound on DIScope.
const vector passed through to codegen
This allows constant vectors using a repr(simd) type to be propagated
through to the backend by reusing the functionality used to do a similar
thing for the simd_shuffle intrinsic
#118209
r? RalfJung
nontemporal_store: make sure that the intrinsic is truly just a hint
The `!nontemporal` flag for stores in LLVM *sounds* like it is just a hint, but actually, it is not -- at least on x86, non-temporal stores need very special treatment by the programmer or else the Rust memory model breaks down. LLVM still treats these stores as-if they were normal stores for optimizations, which is [highly dubious](https://github.com/llvm/llvm-project/issues/64521). Let's avoid all that dubiousness by making our own non-temporal stores be truly just a hint, which is possible on some targets (e.g. ARM). On all other targets, non-temporal stores become regular stores.
~~Blocked on https://github.com/rust-lang/stdarch/pull/1541 propagating to the rustc repo, to make sure the `_mm_stream` intrinsics are unaffected by this change.~~
Fixes https://github.com/rust-lang/rust/issues/114582
Cc `@Amanieu` `@workingjubilee`
By splitting the `FnSig` within `TyKind::FnPtr` into `FnSigTys` and
`FnHeader`, which can be packed more efficiently. This reduces the size
of the hot `TyKind` type from 32 bytes to 24 bytes on 64-bit platforms.
This reduces peak memory usage by a few percent on some benchmarks. It
also reduces cache misses and page faults similarly, though this doesn't
translate to clear cycles or wall-time improvements on CI.
codegen: better centralize function declaration attribute computation
For some reason, the codegen backend has two functions that compute which attributes a function declaration gets: `apply_attrs_llfn` and `attributes::from_fn_attrs`. They are called in different places, on entirely different layers of abstraction.
To me the code seems cleaner if we centralize this entirely in `apply_attrs_llfn`, so that's what this PR does.
Make create_dll_import_lib easier to implement
This will make it easier to implement raw-dylib support in cg_clif and cg_gcc. This PR doesn't yet include an create_dll_import_lib implementation for cg_clif as I need to correctly implement dllimport in cg_clif first before raw-dylib can work at all with cg_clif.
Required for https://github.com/rust-lang/rustc_codegen_cranelift/issues/1345
Add `f16` and `f128` math functions
This adds intrinsics and math functions for `f16` and `f128` floating point types. Support is quite limited and some things are broken so tests don't run on many platforms, but this provides a starting point.
Line 0 has a special meaning in DWARF. From the version 5 spec:
The compiler may emit the value 0 in cases
where an instruction cannot be attributed to any
source line.
DUMMY_SP spans cannot be attributed to any line. However, because rustc
internally stores line numbers starting at zero, lookup_debug_loc() adjusts
every line number by one. Special casing DUMMY_SP to actually emit line 0
ensures rustc communicates to the debugger that there's no meaningful source
code for this instruction, rather than telling the debugger to jump to line 1
randomly.
Since LLVM <https://reviews.llvm.org/D99439> (4c7f820b2b20, "Update
@llvm.powi to handle different int sizes for the exponent"), the size of
the integer can be specified for the `powi` intrinsic. Make use of this
so it is more obvious that integer size is consistent across all float
types.
This feature is available since LLVM 13 (October 2021). Based on
bootstrap we currently support >= 17.0, so there should be no support
problems.
When an archive fails to build, print the path
Currently the output on failure is as follows:
Compiling block-buffer v0.10.4
Compiling crypto-common v0.1.6
Compiling digest v0.10.7
Compiling sha2 v0.10.8
Compiling xz2 v0.1.7
error: failed to build archive: No such file or directory
error: could not compile `bootstrap` (lib) due to 1 previous error
Change this to print which file is being constructed, to give some hint about what is going on.
error: failed to build archive at `path/to/output`: No such file or directory
Rollup of 4 pull requests
Successful merges:
- #127574 (elaborate unknowable goals)
- #128141 (Set branch protection function attributes)
- #128315 (Fix vita build of std and forbid unsafe in unsafe in the os/vita module)
- #128339 ([rustdoc] Make the buttons remain when code example is clicked)
r? `@ghost`
`@rustbot` modify labels: rollup
Add `select_unpredictable` to force LLVM to use CMOV
Since https://reviews.llvm.org/D118118, LLVM will no longer turn CMOVs into branches if it comes from a `select` marked with an `unpredictable` metadata attribute.
This PR introduces `core::intrinsics::select_unpredictable` which emits such a `select` and uses it in the implementation of `binary_search_by`.
Set branch protection function attributes
Since LLVM 19, it is necessary to set not only module flags, but also function attributes for branch protection on aarch64. See e15d67cfc2 for the relevant LLVM change.
Fixes https://github.com/rust-lang/rust/issues/127829.
Update compiler_builtins to 0.1.114
The `weak-intrinsics` feature was removed from compiler_builtins in https://github.com/rust-lang/compiler-builtins/pull/598, so dropped the `compiler-builtins-weak-intrinsics` feature from alloc/std/sysroot.
In https://github.com/rust-lang/compiler-builtins/pull/593, some builtins for f16/f128 were added. These don't work for all compiler backends, so add a `compiler-builtins-no-f16-f128` feature and disable it for cranelift and gcc.
deps: dedup object, wasmparser, wasm-encoder
* dedups one `object`, additional dupe will be removed, with next `thorin-dwp` update
* `wasmparser` pinned to minor versions, so full merge isn't possible
* same with `wasm-encoder`
Turned off some features for `wasmparser` (see features https://github.com/bytecodealliance/wasm-tools/blob/v1.208.1/crates/wasmparser/Cargo.toml) in `run-make-support`, looks working?
Since https://reviews.llvm.org/D118118, LLVM will no longer turn CMOVs
into branches if it comes from a `select` marked with an `unpredictable`
metadata attribute.
This PR introduces `core::intrinsics::select_unpredictable` which emits
such a `select` and uses it in the implementation of `binary_search_by`.
compiler: Never debug_assert in codegen
In the name of Turing and his Hoarey heralds, assert our truths before creating a monster!
The `rustc_codegen_llvm` and `rustc_codegen_ssa` crates are fairly critical for rustc's correctness. Small mistakes here can easily result in undefined behavior, since a "small mistake" can mean something like "link and execute the wrong code". We should probably run any and all asserts in these modules unconditionally on whether this is a "debug build", and damn the costs in performance.
...Especially because the costs in performance seem to be *nothing*. It is not clear how much correctness we gain here, but I'll take free correctness improvements.
Since LLVM 19, it is necessary to set not only module flags, but
also function attributes for branch protection on aarch64. See
e15d67cfc2
for the relevant LLVM change.
rustc_target: add known safe s390x target features
This pull request adds known safe target features for s390x (aka IBM Z systems).
Currently, these features are unstable since stabilizing the target features requires submitting proposals.
The `vector` feature was added in IBM Z13 (`arch11`), and this is a SIMD feature for the newer IBM Z systems.
The `backchain` attribute is the IBM Z way of adding frame pointers like unwinding capabilities (the "frame-pointer" switch on IBM Z and IBM POWER platforms will add _emulated_ frame pointers to the binary, which profilers can't use for unwinding the stack).
Both attributes can be applied at the LLVM module or function levels. However, the `backchain` attribute has to be enabled for all the functions in the call stack to get a successful unwind process.
Handle .init_array link_section specially on wasm
Given that wasm-ld now has support for [.init_array](8f2bd8ae68/llvm/lib/MC/WasmObjectWriter.cpp (L1852)), it appears we can easily implement that section by falling through to the normal path rather than taking the typical custom_section path for wasm.
The wasm-ld appears to have a bunch of limitations. Only one static with the `link_section` in a crate or else you hit the fatal error in the link above "only one .init_array section fragment supported". They do not get merged.
You can still call multiple constructors by setting it to an array.
```
unsafe extern "C" fn ctor() {
println!("foo");
}
#[used]
#[link_section = ".init_array"]
static FOO: [unsafe extern "C" fn(); 2] = [ctor, ctor];
```
Another issue appears to be that if crate *A* depends on crate *B*, but *A* doesn't call any symbols from *B* and *B* doesn't `#[export_name = ...]` any symbols, then crate *B*'s constructor will not be called. The workaround to this is to provide an exported symbol in crate *B*.
... this is a special attribute that was made to be a target-feature in
LLVM 18+, but in all previous versions, this "feature" is a naked
attribute. We will have to handle this situation differently than all
other target-features.
Sync ar_archive_writer to LLVM 18.1.3
From LLVM 15.0.0-rc3. This adds support for COFF archives containing Arm64EC object files and has various fixes for AIX big archive files.
Currently the output on failure is as follows:
Compiling block-buffer v0.10.4
Compiling crypto-common v0.1.6
Compiling digest v0.10.7
Compiling sha2 v0.10.8
Compiling xz2 v0.1.7
error: failed to build archive: No such file or directory
error: could not compile `bootstrap` (lib) due to 1 previous error
Print which file is being constructed to give some hint about what is
going on.
In the future, branch and MC/DC mappings might have expressions that don't
correspond to any single point in the control-flow graph. That makes it
trickier to keep track of which expressions should expect an `ExpressionUsed`
node.
We therefore sidestep that complexity by only performing `ExpressionUsed`
simplification for expressions associated directly with ordinary `Code`
mappings.
Fix incorrect NDEBUG handling in LLVM bindings
We currently compile our LLVM bindings using `-DNDEBUG` if debuginfo for LLVM is disabled. However, `NDEBUG` doesn't have any relation to debuginfo, it controls whether assertions are enabled.
Split the LLVM_NDEBUG environment variable into two, so that assertions and debuginfo are controlled independently.
After this change, `LLVMRustDIBuilderInsertDeclareAtEnd` triggers an assertion failure on LLVM 19 due to an incorrect cast. Fix it by removing the unused return value entirely.
r? `@cuviper`
The return value changed from an Instruction to a DbgRecord in
LLVM 19. As we don't actually use the result, drop the return
value entirely to support both.
Rollup of 8 pull requests
Successful merges:
- #124599 (Suggest borrowing on fn argument that is `impl AsRef`)
- #127572 (Don't mark `DEBUG_EVENT` struct as `repr(packed)`)
- #127588 (core: Limit remaining f16 doctests to x86_64 linux)
- #127591 (Make sure that labels are defined after the primary span in diagnostics)
- #127598 (Allows `#[diagnostic::do_not_recommend]` to supress trait impls in suggestions as well)
- #127599 (Rename `lazy_cell_consume` to `lazy_cell_into_inner`)
- #127601 (check is_ident before parse_ident)
- #127605 (Remove extern "wasm" ABI)
r? `@ghost`
`@rustbot` modify labels: rollup
Add `f16` and `f128` as simd types in LLVM
`@sayantn` is working on adding SIMD for `f16` and hitting the `FloatingPointVector` error. This should fix it and unblock adding support for `simd_fma` and `simd_fabs` in stdarch.
Remove the unstable `extern "wasm"` ABI (`wasm_abi` feature tracked
in #83788).
As discussed in https://github.com/rust-lang/rust/pull/127513#issuecomment-2220410679
and following, this ABI is a failed experiment that did not end
up being used for anything. Keeping support for this ABI in LLVM 19
would require us to switch wasm targets to the `experimental-mv`
ABI, which we do not want to do.
It should be noted that `Abi::Wasm` was internally used for two
things: The `-Z wasm-c-abi=legacy` ABI that is still used by
default on some wasm targets, and the `extern "wasm"` ABI. Despite
both being `Abi::Wasm` internally, they were not the same. An
explicit `extern "wasm"` additionally enabled the `+multivalue`
feature.
I've opted to remove `Abi::Wasm` in this patch entirely, instead
of keeping it as an ABI with only internal usage. Both
`-Z wasm-c-abi` variants are now treated as part of the normal
C ABI, just with different different treatment in
adjust_for_foreign_abi.
Add Natvis visualiser and debuginfo tests for `f16`
To render `f16`s in debuggers on MSVC targets, this PR changes the compiler to output `f16`s as `struct f16 { bits: u16 }`, and includes a Natvis visualiser that manually converts the `f16`'s bits to a `float` which is can then be displayed by debuggers. `gdb`, `lldb` and `cdb` tests are also included for `f16` .
`f16`/`f128` MSVC debug info issue: #121837
Tracking issue: #116909
Miri function identity hack: account for possible inlining
Having a non-lifetime generic is not the only reason a function can be duplicated. Another possibility is that the function may be eligible for cross-crate inlining. So also take into account the inlining attribute in this Miri hack for function pointer identity.
That said, `cross_crate_inlinable` will still sometimes return true even for `inline(never)` functions:
- when they are `DefKind::Ctor(..) | DefKind::Closure` -- I assume those cannot be `InlineAttr::Never` anyway?
- when `cross_crate_inline_threshold == InliningThreshold::Always`
so maybe this is still not quite the right criterion to use for function pointer identity.
Re-implement a type-size based limit
r? lcnr
This PR reintroduces the type length limit added in #37789, which was accidentally made practically useless by the caching changes to `Ty::walk` in #72412, which caused the `walk` function to no longer walk over identical elements.
Hitting this length limit is not fatal unless we are in codegen -- so it shouldn't affect passes like the mir inliner which creates potentially very large types (which we observed, for example, when the new trait solver compiles `itertools` in `--release` mode).
This also increases the type length limit from `1048576 == 2 ** 20` to `2 ** 24`, which covers all of the code that can be reached with craterbot-check. Individual crates can increase the length limit further if desired.
Perf regression is mild and I think we should accept it -- reinstating this limit is important for the new trait solver and to make sure we don't accidentally hit more type-size related regressions in the future.
Fixes#125460
Since this codegen flag now only controls LLVM-generated comments rather than
all assembly comments, make the name more accurate (and also match Clang).
`-Z patchable-function-entry` works like `-fpatchable-function-entry`
on clang/gcc. The arguments are total nop count and function offset.
See MCP rust-lang/compiler-team#704
Deprecate no-op codegen option `-Cinline-threshold=...`
This deprecates `-Cinline-threshold` since using it has no effect. This has been the case since the new LLVM pass manager started being used, more than 2 years ago.
Recommend using `-Cllvm-args=--inline-threshold=...` instead.
Closes#89742 which is E-help-wanted.
Add `f16` inline ASM support for 32-bit ARM
Adds `f16` inline ASM support for 32-bit ARM. SIMD vector types are taken from [here](https://developer.arm.com/architectures/instruction-sets/intrinsics/#f:`@navigationhierarchiesreturnbasetype=[float]&f:@navigationhierarchieselementbitsize=[16]&f:@navigationhierarchiesarchitectures=[A32]).`
Relevant issue: #125398
Tracking issue: #116909
`@rustbot` label +F-f16_and_f128
Add `f16` inline ASM support for RISC-V
This PR adds `f16` inline ASM support for RISC-V. A `FIXME` is left for `f128` support as LLVM does not support the required `Q` (Quad-Precision Floating-Point) extension yet.
Relevant issue: #125398
Tracking issue: #116909
`@rustbot` label +F-f16_and_f128
Honor collapse_debuginfo for statics.
fixes#126363
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Also sort `crt-static` in `--print target-features` output
I didn't find `crt-static` at first (for `x86_64-unknown-linux-gnu`), because it was put at the bottom of the large and otherwise sorted list.
Fully sort the list before we print it.
Note that `llvm_target_features` starts out and remains sorted and does not need to be sorted an extra time.
On my machine the diff is just:
```diff
$ diff -u /tmp/before2.txt /tmp/after2.txt
--- /tmp/before2.txt 2024-06-13 20:40:27.091636592 +0200
+++ /tmp/after2.txt 2024-06-13 20:39:54.584894891 +0200
``@@`` -20,6 +20,7 ``@@``
bmi1 - Support BMI instructions.
bmi2 - Support BMI2 instructions.
cmpxchg16b - 64-bit with cmpxchg16b (this is true for most x86-64 chips, but not the first AMD chips).
+ crt-static - Enables C Run-time Libraries to be statically linked.
ermsb - REP MOVS/STOS are fast.
f16c - Support 16-bit floating point conversion instructions.
fma - Enable three-operand fused multiple-add.
``@@`` -49,7 +50,6 ``@@``
xsavec - Support xsavec instructions.
xsaveopt - Support xsaveopt instructions.
xsaves - Support xsaves instructions.
- crt-static - Enables C Run-time Libraries to be statically linked.
Code-generation features supported by LLVM for this target:
16bit-mode - 16-bit mode (i8086).
```
I couldn't find a ui test that tested this output. Let's see if CI finds a regression tests.
This deprecates `-Cinline-threshold` since using it has no effect. This
has been the case since the new LLVM pass manager started being used,
more than 2 years ago.
I didn't find `crt-static` at first (for `x86_64-unknown-linux-gnu`),
because it was put at the bottom the large and otherwise sorted list.
Fully sort the list before we print it.
Note that `llvm_target_features` starts out sorted and does not need to
be sorted an extra time.
We already do this for a number of crates, e.g. `rustc_middle`,
`rustc_span`, `rustc_metadata`, `rustc_span`, `rustc_errors`.
For the ones we don't, in many cases the attributes are a mess.
- There is no consistency about order of attribute kinds (e.g.
`allow`/`deny`/`feature`).
- Within attribute kind groups (e.g. the `feature` attributes),
sometimes the order is alphabetical, and sometimes there is no
particular order.
- Sometimes the attributes of a particular kind aren't even grouped
all together, e.g. there might be a `feature`, then an `allow`, then
another `feature`.
This commit extends the existing sorting to all compiler crates,
increasing consistency. If any new attribute line is added there is now
only one place it can go -- no need for arbitrary decisions.
Exceptions:
- `rustc_log`, `rustc_next_trait_solver` and `rustc_type_ir_macros`,
because they have no crate attributes.
- `rustc_codegen_gcc`, because it's quasi-external to rustc (e.g. it's
ignored in `rustfmt.toml`).
Directly add extension instead of using `Path::with_extension`
`Path::with_extension` has a nice footgun when the original path doesn't contain an extension: Anything after the last dot gets removed.
Make repr(packed) vectors work with SIMD intrinsics
In #117116 I fixed `#[repr(packed, simd)]` by doing the expected thing and removing padding from the layout. This should be the last step in providing a solution to rust-lang/portable-simd#319
Rollup of 6 pull requests
Successful merges:
- #125263 (rust-lld: fallback to rustc's sysroot if there's no path to the linker in the target sysroot)
- #125345 (rustc_codegen_llvm: add support for writing summary bitcode)
- #125362 (Actually use TAIT instead of emulating it)
- #125412 (Don't suggest adding the unexpected cfgs to the build-script it-self)
- #125445 (Migrate `run-make/rustdoc-with-short-out-dir-option` to `rmake.rs`)
- #125452 (Cleanup check-cfg handling in core and std)
r? `@ghost`
`@rustbot` modify labels: rollup
rustc_codegen_llvm: add support for writing summary bitcode
Typical uses of ThinLTO don't have any use for this as a standalone file, but distributed ThinLTO uses this to make the linker phase more efficient. With clang you'd do something like `clang -flto=thin -fthin-link-bitcode=foo.indexing.o -c foo.c` and then get both foo.o (full of bitcode) and foo.indexing.o (just the summary or index part of the bitcode). That's then usable by a two-stage linking process that's more friendly to distributed build systems like bazel, which is why I'm working on this area.
I talked some to `@teresajohnson` about naming in this area, as things seem to be a little confused between various blog posts and build systems. "bitcode index" and "bitcode summary" tend to be a little too ambiguous, and she tends to use "thin link bitcode" and "minimized bitcode" (which matches the descriptions in LLVM). Since the clang option is thin-link-bitcode, I went with that to try and not add a new spelling in the world.
Per `@dtolnay,` you can work around the lack of this by using `lld --thinlto-index-only` to do the indexing on regular .o files of bitcode, but that is a bit wasteful on actions when we already have all the information in rustc and could just write out the matching minimized bitcode. I didn't test that at all in our infrastructure, because by the time I learned that I already had this patch largely written.
If we don't do this, some versions of LLVM (at least 17, experimentally)
will double-emit some error messages, which is how I noticed this. Given
that it seems to be costing some extra work, let's only request the
summary bitcode production if we'll actually bother writing it down,
otherwise skip it.
Typical uses of ThinLTO don't have any use for this as a standalone
file, but distributed ThinLTO uses this to make the linker phase more
efficient. With clang you'd do something like `clang -flto=thin
-fthin-link-bitcode=foo.indexing.o -c foo.c` and then get both foo.o
(full of bitcode) and foo.indexing.o (just the summary or index part of
the bitcode). That's then usable by a two-stage linking process that's
more friendly to distributed build systems like bazel, which is why I'm
working on this area.
I talked some to @teresajohnson about naming in this area, as things
seem to be a little confused between various blog posts and build
systems. "bitcode index" and "bitcode summary" tend to be a little too
ambiguous, and she tends to use "thin link bitcode" and "minimized
bitcode" (which matches the descriptions in LLVM). Since the clang
option is thin-link-bitcode, I went with that to try and not add a new
spelling in the world.
Per @dtolnay, you can work around the lack of this by using `lld
--thinlto-index-only` to do the indexing on regular .o files of
bitcode, but that is a bit wasteful on actions when we already have all
the information in rustc and could just write out the matching minimized
bitcode. I didn't test that at all in our infrastructure, because by the
time I learned that I already had this patch largely written.
This code for recalculating `mcdc_bitmap_bytes` doesn't provide any benefit,
because its result won't have changed from the value in `FunctionCoverageInfo`
that was computed during the MIR instrumentation pass.
Rollup of 5 pull requests
Successful merges:
- #124615 (coverage: Further simplify extraction of mapping info from MIR)
- #124778 (Fix parse error message for meta items)
- #124797 (Refactor float `Primitive`s to a separate `Float` type)
- #124888 (Migrate `run-make/rustdoc-output-path` to rmake)
- #124957 (Make `Ty::builtin_deref` just return a `Ty`)
r? `@ghost`
`@rustbot` modify labels: rollup
Refactor float `Primitive`s to a separate `Float` type
Now there are 4 of them, it makes sense to refactor `F16`, `F32`, `F64` and `F128` out of `Primitive` and into a separate `Float` type (like integers already are). This allows patterns like `F16 | F32 | F64 | F128` to be simplified into `Float(_)`, and is consistent with `ty::FloatTy`.
As a side effect, this PR also makes the `Ty::primitive_size` method work with `f16` and `f128`.
Tracking issue: #116909
`@rustbot` label +F-f16_and_f128
codegen: memmove/memset cannot be non-temporal
non-temporal memset is not a thing.
And for memmove, since the LLVM backend doesn't support this, surely we don't need it in the GCC backend.
LLVM has updated data layouts to specify `Fn32` on 64-bit ARM to avoid
C++ accidentally underaligning functions when trying to comply with
member function ABIs.
This should only affect Rust in cases where we had a similar bug (I
don't believe we have one), but our data layout must match to generate
code.
As a compatibility adaptatation, if LLVM is not version 19 yet, `Fn32`
gets voided from the data layout.
See llvm/llvm-project#90415
coverage: Clean up creation of MC/DC condition bitmaps
This PR improves the code for creating and initializing [MC/DC](https://en.wikipedia.org/wiki/Modified_condition/decision_coverage) condition bitmap variables, as introduced by #123409 and modified by #124255.
- The condition bitmap variables are now created eagerly at the start of per-function codegen, via a new `init_coverage` method in `CoverageInfoBuilderMethods`. This avoids having to retroactively create the bitmaps while doing codegen for an individual coverage statement.
- As a result, we can now create and initialize those bitmaps using existing safe APIs, instead of having to perform our own unsafe call to `llvm::LLVMBuildAlloca`.
- This PR also tweaks the way we count the number of condition bitmaps needed, by tracking the total number of bitmaps needed (max depth + 1), instead of only tracking the maximum depth. This reduces the potential for subtle off-by-one confusion.
Stabilize the size of incr comp object file names
The current implementation does not produce stable-length paths, and we create the paths in a way that makes our allocation behavior is nondeterministic. I think `@eddyb` fixed a number of other cases like this in the past, and this PR fixes another one. Whether that actually matters I have no idea, but we still have bimodal behavior in rustc-perf and the non-uniformity in `find` and `ls` was bothering me.
I've also removed the truncation of the mangled CGU names. Before this PR incr comp paths look like this:
```
target/debug/incremental/scratch-38izrrq90cex7/s-gux6gz0ow8-1ph76gg-ewe1xj434l26w9up5bedsojpd/261xgo1oqnd90ry5.o
```
And after, they look like this:
```
target/debug/incremental/scratch-035omutqbfkbw/s-gux6borni0-16r3v1j-6n64tmwqzchtgqzwwim5amuga/55v2re42sztc8je9bva6g8ft3.o
```
On the one hand, I'm sure this will break some people's builds because they're on Windows and only a few bytes from the path length limit. But if we're that seriously worried about the length of our file names, I have some other ideas on how to make them smaller. And last time I deleted some hash truncations from the compiler, there was a huge drop in the number if incremental compilation ICEs that were reported: https://github.com/rust-lang/rust/pull/110367https://github.com/rust-lang/rust/pull/110367
---
Upon further reading, this PR actually fixes a bug. This comment says the CGU names are supposed to be a fixed-length hash, and before this PR they aren't: ca7d34efa9/compiler/rustc_monomorphize/src/partitioning.rs (L445-L448)
Because this now always takes place at the start of the function, we can just
use the normal `alloca` method and then initialize each bitmap immediately.
This patch also moves bitmap setup out of the `mcdc_parameters` method, because
there is no longer any particular reason for it to be there.
Remove many `#[macro_use] extern crate foo` items
This requires the addition of more `use` items, which often make the code more verbose. But they also make the code easier to read, because `#[macro_use]` obscures where macros are defined.
r? `@fee1-dead`
MCDC coverage: support nested decision coverage
#123409 provided the initial MCDC coverage implementation.
As referenced in #124144, it does not currently support "nested" decisions, like the following example :
```rust
fn nested_if_in_condition(a: bool, b: bool, c: bool) {
if a && if b || c { true } else { false } {
say("yes");
} else {
say("no");
}
}
```
Note that there is an if-expression (`if b || c ...`) embedded inside a boolean expression in the decision of an outer if-expression.
This PR proposes a workaround for this cases, by introducing a Decision context stack, and by handing several `temporary condition bitmaps` instead of just one.
When instrumenting boolean expressions, if the current node is a leaf condition (i.e. not a `||`/`&&` logical operator nor a `!` not operator), we insert a new decision context, such that if there are more boolean expressions inside the condition, they are handled as separate expressions.
On the codegen LLVM side, we allocate as many `temp_cond_bitmap`s as necessary to handle the maximum encountered decision depth.
Add decision_depth field to TVBitmapUpdate/CondBitmapUpdate statements
Add decision_depth field to BcbMappingKinds MCDCBranch and MCDCDecision
Add decision_depth field to MCDCBranchSpan and MCDCDecisionSpan
Set writable and dead_on_unwind attributes for sret arguments
Set the `writable` and `dead_on_unwind` attributes for `sret` arguments. This allows call slot optimization to remove more memcpy's.
See https://llvm.org/docs/LangRef.html#parameter-attributes for the specification of these attributes. In short, the statement we're making here is that:
* The return slot is writable.
* The return slot will not be read if the function unwinds.
Fixes https://github.com/rust-lang/rust/issues/90595.
Stop using LLVM struct types for alloca
The alloca type has no semantic meaning, only the size (and alignment, but we specify it explicitly) matter. Using `[N x i8]` is a more direct way to specify that we want `N` bytes, and avoids relying on LLVM's struct layout. It is likely that a future LLVM version will change to an untyped alloca representation.
Split out from #121577.
r? `@ghost`
Dellvmize some intrinsics (use `u32` instead of `Self` in some integer intrinsics)
This implements https://github.com/rust-lang/compiler-team/issues/693 minus what was implemented in #123226.
Note: I decided to _not_ change `shl`/... builder methods, as it just doesn't seem worth it.
r? ``@scottmcm``
[cleanup] [llvm backend] Prevent creating the same `Instance::mono` multiple times
Just a little thing I came across while going through the code.
r? ```@oli-obk```
Add support for Arm64EC to the Standard Library
Adds the final pieces so that the standard library can be built for arm64ec-pc-windows-msvc (initially added in #119199)
* Bumps `windows-sys` to 0.56.0, which adds support for Arm64EC.
* Correctly set the `isEC` parameter for LLVM's `writeArchive` function.
* Add `#![feature(asm_experimental_arch)]` to library crates where Arm64EC inline assembly is used, as it is currently unstable.
This makes sure that &[] is just as efficient as indirecting through
unsafe code (from_raw_parts). No new stable guarantee is intended about
whether or not we do this, this is just an optimization.
Co-authored-by: Ralf Jung <post@ralfj.de>
Add the missing inttoptr when we ptrtoint in ptr atomics
Ralf noticed this here: https://github.com/rust-lang/rust/pull/122220#discussion_r1535172094
Our previous codegen forgot to add the cast back to integer type. The code compiles anyway, because of course all locals are in-memory to start with, so previous codegen would do the integer atomic, store the integer to a local, then load a pointer from that local. Which is definitely _not_ what we wanted: That's an integer-to-pointer transmute, so all pointers returned by these `AtomicPtr` methods didn't have provenance. Yikes.
Here's the IR for `AtomicPtr::fetch_byte_add` on 1.76: https://godbolt.org/z/8qTEjeraY
```llvm
define noundef ptr `@atomicptr_fetch_byte_add(ptr` noundef nonnull align 8 %a, i64 noundef %v) unnamed_addr #0 !dbg !7 {
start:
%0 = alloca ptr, align 8, !dbg !12
%val = inttoptr i64 %v to ptr, !dbg !12
call void `@llvm.lifetime.start.p0(i64` 8, ptr %0), !dbg !28
%1 = ptrtoint ptr %val to i64, !dbg !28
%2 = atomicrmw add ptr %a, i64 %1 monotonic, align 8, !dbg !28
store i64 %2, ptr %0, align 8, !dbg !28
%self = load ptr, ptr %0, align 8, !dbg !28
call void `@llvm.lifetime.end.p0(i64` 8, ptr %0), !dbg !28
ret ptr %self, !dbg !33
}
```
r? `@RalfJung`
cc `@nikic`
Make `PlaceRef` and `OperandValue::Ref` share a common `PlaceValue` type
Both `PlaceRef` and `OperandValue::Ref` need the triple of the backend pointer immediate, the optional backend metadata for DSTs, and the actual alignment of the place (since it can differ from the ABI alignment).
This PR introduces a new `PlaceValue` type for those three values, leaving [`PlaceRef`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_codegen_ssa/mir/place/struct.PlaceRef.html) with the `TyAndLayout` and a `PlaceValue`, just like how [`OperandRef`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_codegen_ssa/mir/operand/struct.OperandRef.html) is a `TyAndLayout` and an `OperandValue`.
This means that various places that use `Ref`s as places can just pass the `PlaceValue` along, like in the below excerpt from the diff:
```diff
match operand.val {
- OperandValue::Ref(ptr, meta, align) => {
- debug_assert_eq!(meta, None);
+ OperandValue::Ref(source_place_val) => {
+ debug_assert_eq!(source_place_val.llextra, None);
debug_assert!(matches!(operand_kind, OperandValueKind::Ref));
- let fake_place = PlaceRef::new_sized_aligned(ptr, cast, align);
+ let fake_place = PlaceRef { val: source_place_val, layout: cast };
Some(bx.load_operand(fake_place).val)
}
```
There's more refactoring that I'd like to do after this, but I wanted to stop the PR here where it's hopefully easy (albeit probably not quick) to review since I tried to keep every change line-by-line clear. (Most are just adding `.val` to get to a field.)
You can also go commit-at-a-time if you'd like. Each passed tidy and the codegen tests on my machine (though I didn't run the cg_gcc ones).
I added this back in 111999, but I no longer think it's a good idea
- It had to get scaled back to only power-of-two things to not break a bunch of targets
- LLVM seems to be getting better at memcpy removal anyway
- Introducing vector instructions has seemed to sometimes (115515) make autovectorization worse
So this removes it from the codegen crates entirely, and instead just tries to use <https://doc.rust-lang.org/nightly/nightly-rustc/rustc_codegen_ssa/traits/builder/trait.BuilderMethods.html#method.typed_place_copy> instead of direct `memcpy` so things will still use load/store for immediates.
sanitizers: Create the rustc_sanitizers crate
Create the `rustc_sanitizers` crate and move the source code for the CFI and KCFI sanitizers to it. The tracking issue for reviewing and moving sanitizers into a compiler crate is #123619. This is part of our work to organize and stabilize support for the sanitizers. (See our roadmap at https://hackmd.io/`@rcvalle/S1Ou9K6H6.)`
Create the rustc_sanitizers crate and move the source code for the CFI
and KCFI sanitizers to it.
Co-authored-by: David Wood <agile.lion3441@fuligin.ink>
The actual ABI implication here is that in some cases the values
are required to be "consecutive", i.e. must either all be passed
in registers or all on stack (without padding).
Adjust the code to either use Uniform::new() or Uniform::consecutive()
depending on which behavior is needed.
Then, when lowering this in LLVM, skip the [1 x i128] to i128
simplification if is_consecutive is set. i128 is the only case
I'm aware of where this is problematic right now. If we find
other cases, we can extend this (either based on target information
or possibly just by not simplifying for is_consecutive entirely).
When passing a 16 (or higher) aligned struct by value on ppc64le,
it needs to be passed as an array of `i128` rather than an array
of `i64`. This will force the use of an even starting register.
For the case of a 16 byte struct with alignment 16 it is important
that `[1 x i128]` is used instead of `i128` -- apparently, the
latter will get treated similarly to `[2 x i64]`, not exhibiting
the correct ABI. Add a `force_array` flag to `Uniform` to support
this.
The relevant clang code can be found here:
fe2119a7b0/clang/lib/CodeGen/Targets/PPC.cpp (L878-L884)fe2119a7b0/clang/lib/CodeGen/Targets/PPC.cpp (L780-L784)
I think the corresponding psABI wording is this:
> Fixed size aggregates and unions passed by value are mapped to as
> many doublewords of the parameter save area as the value uses in
> memory. Aggregrates and unions are aligned according to their
> alignment requirements. This may result in doublewords being
> skipped for alignment.
In particular the last sentence.
Fixes https://github.com/rust-lang/rust/issues/122767.
CFI: Restore typeid_for_instance default behavior
Restore typeid_for_instance default behavior of performing self type erasure, since it's the most common case and what it does most of the time. Using concrete self (or not performing self type erasure) is for assigning a secondary type id, and secondary type ids are only assigned when they're unique and to methods, and also are only tested for when methods are used as function pointers.
Add aarch64-apple-visionos and aarch64-apple-visionos-sim tier 3 targets
Introduces `aarch64-apple-visionos` and `aarch64-apple-visionos-sim` as tier 3 targets. This allows native development for the Apple Vision Pro's visionOS platform.
This work has been tracked in https://github.com/rust-lang/compiler-team/issues/642. There is a corresponding `libc` change https://github.com/rust-lang/libc/pull/3568 that is not required for merge.
Ideally we would be able to incorporate [this change](https://github.com/gimli-rs/object/pull/626) to the `object` crate, but the author has stated that a release will not be cut for quite a while. Therefore, the two locations that would reference the xrOS constant from `object` are hardcoded to their MachO values of 11 and 12, accompanied by TODOs to mark the code as needing change. I am open to suggestions on what to do here to get this checked in.
# Tier 3 Target Policy
At this tier, the Rust project provides no official support for a target, so we place minimal requirements on the introduction of targets.
> 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.)
See [src/doc/rustc/src/platform-support/apple-visionos.md](e88379034a/src/doc/rustc/src/platform-support/apple-visionos.md)
> 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 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.
> * If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known to cause issues in Cargo.
This naming scheme matches `$ARCH-$VENDOR-$OS-$ABI` which is matches the iOS Apple Silicon simulator (`aarch64-apple-ios-sim`) and other Apple targets.
> 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.
> - Anything added to the Rust repository must be under the standard Rust license (`MIT OR Apache-2.0`).
> - 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 besubject 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.
This contribution is fully available under the standard Rust license with no additional legal restrictions whatsoever. This PR does not introduce any new dependency less permissive than the Rust license policy.
The new targets do not depend on proprietary libraries.
> 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.
This new target mirrors the standard library for watchOS and iOS, with minor divergences.
> 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/apple-visionos.md](e88379034a/src/doc/rustc/src/platform-support/apple-visionos.md)
> 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.
> 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.
I acknowledge these requirements and intend to ensure that they are met.
This target does not touch any existing tier 2 or tier 1 targets and should not break any other targets.
Restore typeid_for_instance default behavior of performing self type
erasure, since it's the most common case and what it does most of the
time. Using concrete self (or not performing self type erasure) is for
assigning a secondary type id, and secondary type ids are only assigned
when they're unique and to methods, and also are only tested for when
methods are used as function pointers.
Rollup of 9 pull requests
Successful merges:
- #121546 (Error out of layout calculation if a non-last struct field is unsized)
- #122448 (Port hir-tree run-make test to ui test)
- #123212 (CFI: Change type transformation to use TypeFolder)
- #123218 (Add test for getting parent HIR for synthetic HIR node)
- #123324 (match lowering: make false edges more precise)
- #123389 (Avoid panicking unnecessarily on startup)
- #123397 (Fix diagnostic for qualifier in extern block)
- #123431 (Stabilize `proc_macro_byte_character` and `proc_macro_c_str_literals`)
- #123439 (coverage: Remove useless constants)
r? `@ghost`
`@rustbot` modify labels: rollup
coverage: Remove useless constants
After #122972 and #123419, these constants don't serve any useful purpose, so get rid of them.
`@rustbot` label +A-code-coverage
coverage: Correctly report and check LLVM's coverage mapping version
I was puzzled by the fact that the LLVM 18 update (#120055) didn't need to modify this version check, despite the fact that LLVM 18 uses a newer version of the coverage mapping format.
This turned out to be because we were inappropriately hard-coding a specific version (`Version6`) in the C++ wrapper, instead of using `CovMapVersion::CurrentVersion` to reflect the version actually used by LLVM on our behalf.
This PR fixes that, and also changes the Rust-side version check to accept the new coverage mapping version used by LLVM 18, since the necessary compatibility work has already been done.
---
### Quick history of `LLVMRustCoverageMappingVersion`:
- Originally it returned LLVM's `coverage::CovMapVersion::CurrentVersion`, as intended. The Rust-side code would verify it, and also embed it as the actual coverage version number in the output binary.
- At some point it was changed to a hard-coded value, to work around a (now-irrelevant) compatibility issue. This was incorrect (but mostly benign), because the override should have been performed on the Rust side instead, after verifying LLVM's value.
- Later contributors dutifully updated the hard-coded value, because they didn't have enough context to identify the problem.
- With this PR, it once again returns LLVM's current coverage version number, and the Rust-side code checks it against an expected range. We don't override the result, but we do indicate where that override should occur if it ever becomes necessary.
CFI: Support function pointers for trait methods
Adds support for both CFI and KCFI for function pointers to trait methods by attaching both concrete and abstract types to functions.
KCFI does this through generation of a `ReifyShim` on any function pointer for a method that could go into a vtable, and keeping this separate from `ReifyShim`s that are *intended* for vtable us by setting a `ReifyReason` on them.
CFI does this by setting both the concrete and abstract type on every instance.
This should land after #123024 or a similar PR, as it diverges the implementation of CFI vs KCFI.
r? `@compiler-errors`
Rename `expose_addr` to `expose_provenance`
`expose_addr` is a bad name, an address is just a number and cannot be exposed. The operation is actually about the provenance of the pointer.
This PR thus changes the name of the method to `expose_provenance` without changing its return type. There is sufficient precedence for returning a useful value from an operation that does something else without the name indicating such, e.g. [`Option::insert`](https://doc.rust-lang.org/nightly/std/option/enum.Option.html#method.insert) and [`MaybeUninit::write`](https://doc.rust-lang.org/nightly/std/mem/union.MaybeUninit.html#method.write).
Returning the address is merely convenient, not a fundamental part of the operation. This is implied by the fact that integers do not have provenance since
```rust
let addr = ptr.addr();
ptr.expose_provenance();
let new = ptr::with_exposed_provenance(addr);
```
must behave exactly like
```rust
let addr = ptr.expose_provenance();
let new = ptr::with_exposed_provenance(addr);
```
as the result of `ptr.expose_provenance()` and `ptr.addr()` is the same integer. Therefore, this PR removes the `#[must_use]` annotation on the function and updates the documentation to reflect the important part.
~~An alternative name would be `expose_provenance`. I'm not at all opposed to that, but it makes a stronger implication than we might want that the provenance of the pointer returned by `ptr::with_exposed_provenance`[^1] is the same as that what was exposed, which is not yet specified as such IIUC. IMHO `expose` does not make that connection.~~
A previous version of this PR suggested `expose` as name, libs-api [decided on](https://github.com/rust-lang/rust/pull/122964#issuecomment-2033194319) `expose_provenance` to keep the symmetry with `with_exposed_provenance`.
CC `@RalfJung`
r? libs-api
[^1]: I'm using the new name for `from_exposed_addr` suggested by #122935 here.
rename ptr::from_exposed_addr -> ptr::with_exposed_provenance
As discussed on [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/136281-t-opsem/topic/To.20expose.20or.20not.20to.20expose/near/427757066).
The old name, `from_exposed_addr`, makes little sense as it's not the address that is exposed, it's the provenance. (`ptr.expose_addr()` stays unchanged as we haven't found a better option yet. The intended interpretation is "expose the provenance and return the address".)
The new name nicely matches `ptr::without_provenance`.
Add `Ord::cmp` for primitives as a `BinOp` in MIR
Update: most of this OP was written months ago. See https://github.com/rust-lang/rust/pull/118310#issuecomment-2016940014 below for where we got to recently that made it ready for review.
---
There are dozens of reasonable ways to implement `Ord::cmp` for integers using comparison, bit-ops, and branches. Those differences are irrelevant at the rust level, however, so we can make things better by adding `BinOp::Cmp` at the MIR level:
1. Exactly how to implement it is left up to the backends, so LLVM can use whatever pattern its optimizer best recognizes and cranelift can use whichever pattern codegens the fastest.
2. By not inlining those details for every use of `cmp`, we drastically reduce the amount of MIR generated for `derive`d `PartialOrd`, while also making it more amenable to MIR-level optimizations.
Having extremely careful `if` ordering to μoptimize resource usage on broadwell (#63767) is great, but it really feels to me like libcore is the wrong place to put that logic. Similarly, using subtraction [tricks](https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign) (#105840) is arguably even nicer, but depends on the optimizer understanding it (https://github.com/llvm/llvm-project/issues/73417) to be practical. Or maybe [bitor is better than add](https://discourse.llvm.org/t/representing-in-ir/67369/2?u=scottmcm)? But maybe only on a future version that [has `or disjoint` support](https://discourse.llvm.org/t/rfc-add-or-disjoint-flag/75036?u=scottmcm)? And just because one of those forms happens to be good for LLVM, there's no guarantee that it'd be the same form that GCC or Cranelift would rather see -- especially given their very different optimizers. Not to mention that if LLVM gets a spaceship intrinsic -- [which it should](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Suboptimal.20inlining.20in.20std.20function.20.60binary_search.60/near/404250586) -- we'll need at least a rustc intrinsic to be able to call it.
As for simplifying it in Rust, we now regularly inline `{integer}::partial_cmp`, but it's quite a large amount of IR. The best way to see that is with 8811efa88b (diff-d134c32d028fbe2bf835fef2df9aca9d13332dd82284ff21ee7ebf717bfa4765R113) -- I added a new pre-codegen MIR test for a simple 3-tuple struct, and this PR change it from 36 locals and 26 basic blocks down to 24 locals and 8 basic blocks. Even better, as soon as the construct-`Some`-then-match-it-in-same-BB noise is cleaned up, this'll expose the `Cmp == 0` branches clearly in MIR, so that an InstCombine (#105808) can simplify that to just a `BinOp::Eq` and thus fix some of our generated code perf issues. (Tracking that through today's `if a < b { Less } else if a == b { Equal } else { Greater }` would be *much* harder.)
---
r? `@ghost`
But first I should check that perf is ok with this
~~...and my true nemesis, tidy.~~
Use the `Align` type when parsing alignment attributes
Use the `Align` type in `rustc_attr::parse_alignment`, removing the need to call `Align::from_bytes(...).unwrap()` later in the compilation process.
Simplify trim-paths feature by merging all debuginfo options together
This PR simplifies the trim-paths feature by merging all debuginfo options together, as described in https://github.com/rust-lang/rust/issues/111540#issuecomment-1994010274.
And also do some correctness fixes found during the review.
cc `@weihanglo`
r? `@michaelwoerister`
CFI: Fix methods as function pointer cast
Fix casting between methods and function pointers by assigning a secondary type id to methods with their concrete self so they can be used as function pointers.
This was split off from #116404.
cc `@compiler-errors` `@workingjubilee`
Fix casting between methods and function pointers by assigning a
secondary type id to methods with their concrete self so they can be
used as function pointers.
Make `TyCtxt::coroutine_layout` take coroutine's kind parameter
For coroutines that come from coroutine-closures (i.e. async closures), we may have two kinds of bodies stored in the coroutine; one that takes the closure's captures by reference, and one that takes the captures by move.
These currently have identical layouts, but if we do any optimization for these layouts that are related to the upvars, then they will diverge -- e.g. https://github.com/rust-lang/rust/pull/120168#discussion_r1536943728.
This PR relaxes the assertion I added in #121122, and instead make the `TyCtxt::coroutine_layout` method take the `coroutine_kind_ty` argument from the coroutine, which will allow us to differentiate these by-move and by-ref bodies.
coverage: Re-enable `UnreachablePropagation` for coverage builds
This is a sequence of 3 related changes:
- Clean up the existing code that scans for unused functions
- Detect functions that were instrumented for coverage, but have had all their coverage statements removed by later MIR transforms (e.g. `UnreachablePropagation`)
- Re-enable `UnreachablePropagation` in coverage builds
Because we now detect functions that have lost their coverage statements, and treat them as unused, we don't need to worry about `UnreachablePropagation` removing all of those statements. This is demonstrated by `tests/coverage/unreachable.rs`.
Fixes#116171.
If a function was instrumented for coverage, but all of its coverage statements
have been removed by later MIR transforms, it should be treated as "unused"
even if the compiler generates an unreachable stub for it.
Unbox and unwrap the contents of `StatementKind::Coverage`
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.
``@rustbot`` label +A-code-coverage
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.
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.
Some of the marker statements used by coverage are added during MIR building
for use by the InstrumentCoverage pass (during analysis), and are not needed
afterwards.
various clippy fixes
We need to keep the order of the given clippy lint rules before passing them.
Since clap doesn't offer any useful interface for this purpose out of the box,
we have to handle it manually.
Additionally, this PR makes `-D` rules work as expected. Previously, lint rules were limited to `-W`. By enabling `-D`, clippy began to complain numerous lines in the tree, all of which have been resolved in this PR as well.
Fixes#121481
cc `@matthiaskrgr`
Update the minimum external LLVM to 17
With this change, we'll have stable support for LLVM 17 and 18.
For reference, the previous increase to LLVM 16 was #117947.
LLVM's default bad-alloc handler may throw if exceptions are enabled,
and `operator new` isn't hooked at all by default. Now we register our
own handler that prints a message similar to fatal errors, then aborts.
We also call the function that registers the C++ `std::new_handler`.
coverage: Initial support for branch coverage instrumentation
(This is a review-ready version of the changes that were drafted in #118305.)
This PR adds support for branch coverage instrumentation, gated behind the unstable flag value `-Zcoverage-options=branch`. (Coverage instrumentation must also be enabled with `-Cinstrument-coverage`.)
During THIR-to-MIR lowering (MIR building), if branch coverage is enabled, we collect additional information about branch conditions and their corresponding then/else blocks. We inject special marker statements into those blocks, so that the `InstrumentCoverage` MIR pass can reliably identify them even after the initially-built MIR has been simplified and renumbered.
The rest of the changes are mostly just plumbing needed to gather up the information that was collected during MIR building, and include it in the coverage metadata that we embed in the final binary.
Note that `llvm-cov show` doesn't print branch coverage information in its source views by default; that needs to be explicitly enabled with `--show-branches=count` or similar.
---
The current implementation doesn't have any support for instrumenting `if let` or let-chains. I think it's still useful without that, and adding it would be non-trivial, so I'm happy to leave that for future work.
coverage: Remove or migrate all unstable values of `-Cinstrument-coverage`
(This PR was substantially overhauled from its original version, which migrated all of the existing unstable values intact.)
This PR takes the three nightly-only values that are currently accepted by `-Cinstrument-coverage`, completely removes two of them (`except-unused-functions` and `except-unused-generics`), and migrates the third (`branch`) over to a newly-introduced unstable flag `-Zcoverage-options`.
I have a few motivations for wanting to do this:
- It's unclear whether anyone actually uses the `except-unused-*` values, so this serves as an opportunity to either remove them, or prompt existing users to object to their removal.
- After #117199, the stable values of `-Cinstrument-coverage` treat it as a boolean-valued flag, so having nightly-only extra values feels out-of-place.
- Nightly-only values also require extra ad-hoc code to make sure they aren't accidentally exposed to stable users.
- The new system allows multiple different settings to be toggled independently, which isn't possible in the current single-value system.
- The new system makes it easier to introduce new behaviour behind an unstable toggle, and then gather nightly-user feedback before possibly making it the default behaviour for all users.
- The new system also gives us a convenient place to put relatively-narrow options that won't ever be the default, but that nightly users might still want access to.
- It's likely that we will eventually want to give stable users more fine-grained control over coverage instrumentation. The new flag serves as a prototype of what that stable UI might eventually look like.
The `branch` option is a placeholder that currently does nothing. It will be used by #122322 to opt into branch coverage instrumentation.
---
I see `-Zcoverage-options` as something that will exist more-or-less indefinitely, though individual sub-options might come and go as appropriate. I think there will always be some demand for nightly-only toggles, so I don't see `-Zcoverage-options` itself ever being stable, though we might eventually stabilize something similar to it.
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
Fix 32-bit overflows in LLVM composite constants
Inspired by #121868. Fixes unsoundness created when constructing constant arrays, strings, and structs with 2^32 or more elements on x86_64. This introduces copies of a few LLVM functions that have their signatures updated to use size_t in place of unsigned int. Alternatively we could just add overflow checks and just disallow huge composite constants. That introduces less code, but maybe a huge static block of memory is useful in embedded/no-os situations?
Remove the unused `field_remapping` field from `TypeLowering`
The `field_remapping` field of `TypeLowering` has been unused since #121665. This PR removes it, then replaces the `TypeLowering` struct with its only remaining member `&'ll Type`.
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...
```
Stop using LLVM struct types for byval/sret
For `byval` and `sret`, the type has no semantic meaning, only the size matters\*†. Using `[N x i8]` is a more direct way to specify that we want `N` bytes, and avoids relying on LLVM's struct layout.
\*: The alignment would matter, if we didn't explicitly specify it. From what I can tell, we always specified the alignment for `sret`; for `byval`, we didn't until #112157.
†: For `byval`, the hidden copy may be impacted by padding in the LLVM struct type, i.e. padding bytes may not be copied. (I'm not sure if this is done today, but I think it would be legal.) But we manually pad our LLVM struct types specifically to avoid there ever being LLVM-visible padding, so that shouldn't be an issue.
Split out from #121577.
r? `@nikic`
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.
