| Age | Commit message (Collapse) | Author | Lines |
|---|
|
Stabilize order of MonoItems in CGUs and disallow query_instability lint for rustc_monomorphize
The HashStable impl for `CodegenUnit` was incorrect as described in [MCP 533](https://github.com/rust-lang/compiler-team/issues/533). This PR removes any indeterminism from the way codegen units are built. The changes are pretty straightforward.
Part of https://github.com/rust-lang/rust/issues/84447 and [MCP 533](https://github.com/rust-lang/compiler-team/issues/533).
|
|
|
|
rustc_monomorphize
|
|
|
|
|
|
generics' attributes
|
|
|
|
|
|
|
|
Also no longer export noop async_drop_in_place_raw
|
|
Explainer: https://zetanumbers.github.io/book/async-drop-design.html
https://github.com/rust-lang/rust/pull/121801
|
|
|
|
|
|
|
|
Codegen const panic messages as function calls
This skips emitting extra arguments at every callsite (of which there
can be many). For a librustc_driver build with overflow checks enabled,
this cuts 0.7MB from the resulting shared library (see [perf]).
A sample improvement from nightly:
```
leaq str.0(%rip), %rdi
leaq .Lalloc_d6aeb8e2aa19de39a7f0e861c998af13(%rip), %rdx
movl $25, %esi
callq *_ZN4core9panicking5panic17h17cabb89c5bcc999E@GOTPCREL(%rip)
```
to this PR:
```
leaq .Lalloc_d6aeb8e2aa19de39a7f0e861c998af13(%rip), %rdi
callq *_RNvNtNtCsduqIKoij8JB_4core9panicking11panic_const23panic_const_div_by_zero@GOTPCREL(%rip)
```
[perf]: https://perf.rust-lang.org/compare.html?start=a7e4de13c1785819f4d61da41f6704ed69d5f203&end=64fbb4f0b2d621ff46d559d1e9f5ad89a8d7789b&stat=instructions:u
|
|
|
|
Remove `TypeAndMut` from `ty::RawPtr` variant, make it take `Ty` and `Mutability`
Pretty much mechanically converting `ty::RawPtr(ty::TypeAndMut { ty, mutbl })` to `ty::RawPtr(ty, mutbl)` and its fallout.
r? lcnr
cc rust-lang/types-team#124
|
|
"Handle" calls to upstream monomorphizations in compiler_builtins
This is pretty cooked, but I think it works.
compiler-builtins has a long-standing problem that at link time, its rlib cannot contain any calls to `core`. And yet, in codegen we _love_ inserting calls to symbols in `core`, generally from various panic entrypoints.
I intend this PR to attack that problem as completely as possible. When we generate a function call, we now check if we are generating a function call from `compiler_builtins` and whether the callee is a function which was not lowered in the current crate, meaning we will have to link to it.
If those conditions are met, actually generating the call is asking for a linker error. So we don't. If the callee diverges, we lower to an abort with the same behavior as `core::intrinsics::abort`. If the callee does not diverge, we produce an error. This means that compiler-builtins can contain panics, but they'll SIGILL instead of panicking. I made non-diverging calls a compile error because I'm guessing that they'd mostly get into compiler-builtins by someone making a mistake while working on the crate, and compile errors are better than linker errors. We could turn such calls into aborts as well if that's preferred.
|
|
|
|
This skips emitting extra arguments at every callsite (of which there
can be many). For a librustc_driver build with overflow checks enabled,
this cuts 0.7MB from the resulting binary.
|
|
|
|
recursively evaluate the constants in everything that is 'mentioned'
This is another attempt at fixing https://github.com/rust-lang/rust/issues/107503. The previous attempt at https://github.com/rust-lang/rust/pull/112879 seems stuck in figuring out where the [perf regression](https://perf.rust-lang.org/compare.html?start=c55d1ee8d4e3162187214692229a63c2cc5e0f31&end=ec8de1ebe0d698b109beeaaac83e60f4ef8bb7d1&stat=instructions:u) comes from. In https://github.com/rust-lang/rust/pull/122258 I learned some things, which informed the approach this PR is taking.
Quoting from the new collector docs, which explain the high-level idea:
```rust
//! One important role of collection is to evaluate all constants that are used by all the items
//! which are being collected. Codegen can then rely on only encountering constants that evaluate
//! successfully, and if a constant fails to evaluate, the collector has much better context to be
//! able to show where this constant comes up.
//!
//! However, the exact set of "used" items (collected as described above), and therefore the exact
//! set of used constants, can depend on optimizations. Optimizing away dead code may optimize away
//! a function call that uses a failing constant, so an unoptimized build may fail where an
//! optimized build succeeds. This is undesirable.
//!
//! To fix this, the collector has the concept of "mentioned" items. Some time during the MIR
//! pipeline, before any optimization-level-dependent optimizations, we compute a list of all items
//! that syntactically appear in the code. These are considered "mentioned", and even if they are in
//! dead code and get optimized away (which makes them no longer "used"), they are still
//! "mentioned". For every used item, the collector ensures that all mentioned items, recursively,
//! do not use a failing constant. This is reflected via the [`CollectionMode`], which determines
//! whether we are visiting a used item or merely a mentioned item.
//!
//! The collector and "mentioned items" gathering (which lives in `rustc_mir_transform::mentioned_items`)
//! need to stay in sync in the following sense:
//!
//! - For every item that the collector gather that could eventually lead to build failure (most
//! likely due to containing a constant that fails to evaluate), a corresponding mentioned item
//! must be added. This should use the exact same strategy as the ecollector to make sure they are
//! in sync. However, while the collector works on monomorphized types, mentioned items are
//! collected on generic MIR -- so any time the collector checks for a particular type (such as
//! `ty::FnDef`), we have to just onconditionally add this as a mentioned item.
//! - In `visit_mentioned_item`, we then do with that mentioned item exactly what the collector
//! would have done during regular MIR visiting. Basically you can think of the collector having
//! two stages, a pre-monomorphization stage and a post-monomorphization stage (usually quite
//! literally separated by a call to `self.monomorphize`); the pre-monomorphizationn stage is
//! duplicated in mentioned items gathering and the post-monomorphization stage is duplicated in
//! `visit_mentioned_item`.
//! - Finally, as a performance optimization, the collector should fill `used_mentioned_item` during
//! its MIR traversal with exactly what mentioned item gathering would have added in the same
//! situation. This detects mentioned items that have *not* been optimized away and hence don't
//! need a dedicated traversal.
enum CollectionMode {
/// Collect items that are used, i.e., actually needed for codegen.
///
/// Which items are used can depend on optimization levels, as MIR optimizations can remove
/// uses.
UsedItems,
/// Collect items that are mentioned. The goal of this mode is that it is independent of
/// optimizations: the set of "mentioned" items is computed before optimizations are run.
///
/// The exact contents of this set are *not* a stable guarantee. (For instance, it is currently
/// computed after drop-elaboration. If we ever do some optimizations even in debug builds, we
/// might decide to run them before computing mentioned items.) The key property of this set is
/// that it is optimization-independent.
MentionedItems,
}
```
And the `mentioned_items` MIR body field docs:
```rust
/// Further items that were mentioned in this function and hence *may* become monomorphized,
/// depending on optimizations. We use this to avoid optimization-dependent compile errors: the
/// collector recursively traverses all "mentioned" items and evaluates all their
/// `required_consts`.
///
/// This is *not* soundness-critical and the contents of this list are *not* a stable guarantee.
/// All that's relevant is that this set is optimization-level-independent, and that it includes
/// everything that the collector would consider "used". (For example, we currently compute this
/// set after drop elaboration, so some drop calls that can never be reached are not considered
/// "mentioned".) See the documentation of `CollectionMode` in
/// `compiler/rustc_monomorphize/src/collector.rs` for more context.
pub mentioned_items: Vec<Spanned<MentionedItem<'tcx>>>,
```
Fixes #107503
|
|
really only has root collection things under it
|
|
are FnDef/Closure or not
They may become FnDef during monomorphization!
|
|
|
|
|
|
|
|
|
|
|
|
actual overrides in codegen
|
|
cases that used `None`
|
|
|
|
|
|
|
|
add test ensuring simd codegen checks don't run when a static assertion failed
stdarch relies on this to ensure that SIMD indices are in bounds.
I would love to know why this works, but I can't figure out where codegen decides to not codegen a function if a required-const does not evaluate. `@oli-obk` `@bjorn3` do you have any idea?
|
|
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.
|
|
|
|
|
|
|
|
Diagnostic renaming 3
A sequel to https://github.com/rust-lang/rust/pull/121780.
r? `@davidtwco`
|
|
To match `derive(Diagnostic)`.
Also rename `into_diagnostic` as `into_diag`.
|
|
|
|
|
|
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``
|
|
|
|
|
|
instead of checking the attribute
|
|
|
|
Much better!
Note that this involves renaming (and updating the value of)
`DIAGNOSTIC_BUILDER` in clippy.
|
|
|
