Fix ICE: Don't try to evaluate type_consts when eagerly collecting items
This fixes https://github.com/rust-lang/rust/issues/151246
The change is pretty straightforward if the Monomorphization strategy is eager which `-Clink-dead-code=true` sets. This then would lead to the existing code to try and evaluate a `type const` which does not have a body to evaluate leading to an ICE. The change is pretty straight forward just skip over type consts.
This also seems like a sensible choice to me since a MonoItem can only be a Fn, Static, or Asm. A type const is none of the aforementioned.
And even if it was added to the MonoItems list it would then later fail this check:
fe98ddcfcf/compiler/rustc_monomorphize/src/collector.rs (L438-L440)
Since that explicitly checks that the MonoItem's `DefKind` is static and not anything else.
One more change is the addition of a simple test of the example code from https://github.com/rust-lang/rust/issues/151246 that checks that code compiles successfully with `-Clink-dead-code=true`.
The only other change was to make the guard checks a little easier to read by making the logic more linear instead of one big if statement.
r? @BoxyUwU
@rustbot label +F-associated_const_equality +F-min_generic_const_args
Update compiler/rustc_monomorphize/src/collector.rs
Add FIXME(mgca) comment to potentially re-investigate in the future.
Co-Authored-By: Boxy <rust@boxyuwu.dev>
It's described as a "backwards compatibility hack to keep the diff
small". Removing it requires only a modest amount of churn, and the
resulting code is clearer without the invisible derefs.
Ensure that static initializers are acyclic for NVPTX
NVPTX does not support cycles in static initializers (see rust-lang/rust#146787). LLVM produces an error when attempting to generate code for such constructs, like self-referential structs.
To avoid LLVM UB, we emit a post-monomorphization error on the Rust side before reaching codegen.
This is achieved by analyzing a subgraph of the "mono item graph" that only contains statics.
1. Calculate the strongly connected components (SCCs) of the graph.
2. Check for cycles (more than one node in an SCC or one node that references itself).
NVPTX does not support cycles in static initializers. LLVM produces an error when attempting to codegen such constructs (like self referential structs).
To not produce LLVM UB we instead emit a post-monomorphization error on
Rust side before reaching codegen.
This is achieved by analysing a subgraph of the "mono item graph" that
only contains statics:
1. Calculate the strongly connected components (SCCs) of the graph
2. Check for cycles (more than one node in a SCC or exactly one node
which references itself)
The amdgpu target uses vector types in various places. The vector types
can be used on all architectures, there is no associated target feature
that needs to be enabled.
The largest vector type found in LLVM intrinsics is `v32i32`
(`[32 x i32]`) for mfma intrinsics. Note that while this intrinsic is
only supported on some architectures, the vector type itself is
supported on all architectures.
Externally implementable items
Supersedes https://github.com/rust-lang/rust/pull/140010
Tracking issue: https://github.com/rust-lang/rust/issues/125418
Getting started:
```rust
#![feature(eii)]
#[eii(eii1)]
pub fn decl1(x: u64)
// body optional (it's the default)
{
println!("default {x}");
}
// in another crate, maybe
#[eii1]
pub fn decl2(x: u64) {
println!("explicit {x}");
}
fn main() {
decl1(4);
}
```
- tiny perf regression, underlying issue makes multiple things in the compiler slow, not just EII, planning to solve those separately.
- No codegen_gcc support, they don't have bindings for weak symbols yet but could
- No windows support yet for weak definitions
This PR merges the implementation of EII for just llvm + not windows, doesn't yet contain like a new panic handler implementation or alloc handler. With this implementation, it would support implementing the panic handler in terms of EII already since it requires no default implementation so no weak symbols
The PR has been open in various forms for about a year now, but I feel that having some implementation merged to build upon
rename erase_regions to erase_and_anonymize_regions
I find it consistently confusing that `erase_regions` does more than replacing regions with `'erased`. it also makes some code look real goofy to be writing manual folders to erase regions with a comment saying "we cant use erase regions" :> or code that re-calls erase_regions on types with regions already erased just to anonymize all the bound regions.
r? lcnr
idk how i feel about the name being almost twice as long now
This was done in #145740 and #145947. It is causing problems for people
using r-a on anything that uses the rustc-dev rustup package, e.g. Miri,
clippy.
This repository has lots of submodules and subtrees and various
different projects are carved out of pieces of it. It seems like
`[workspace.dependencies]` will just be more trouble than it's worth.
pub async fn impl is monomorphized when func itself is monomorphized
Implentation coroutine (`func::{closure#0}`) is monomorphized, when func itself is monomorphized.
Currently, when `pub async fn foo(..)` is exported from lib and used in several dependent crates, only 'header' function is monomorphized in the defining crate. 'header' function, returning coroutine object, is monomorphized, but the coroutine's poll function (which actually implements all the logic for the function) is not. In such situation, `func::{closure#0}` will be monomorphized in every dependency.
This PR adds monomorphization for `func::{closure#0}` (coroutine poll function), when func itself is monomorphized.
Simple test with one lib async function and ten dependent crates (executable) that use the function, shows 5-7% compilation time improvement (single-threaded).
Fix tail calls to `#[track_caller]` functions
We want `#[track_caller]` to be semver independent, i.e. it should not be a breaking change to add or remove it. Since it changes ABI of a function (adding an additional argument) we have to be careful to preserve this property when adding tail calls.
The only way to achieve this that I can see is:
- we forbid tail calls in functions which are marked with `#[track_caller]` (already implemented)
- tail-calling a `#[track_caller]` marked function downgrades the tail-call to a normal call (or equivalently tail-calls the shim made by fn def to fn ptr cast) (this pr)
Ideally the downgrade would be performed by a MIR pass, but that requires post mono MIR opts (cc ```@saethlin,``` rust-lang/rust#131650). For now I've changed code in cg_ssa to accomodate this behaviour (+ added a hack to mono collector so that the shim is actually generated)
Additionally I added a lint, although I don't think it's strictly necessary.
Alternative to rust-lang/rust#144762 (and thus closesrust-lang/rust#144762)
Fixes https://github.com/rust-lang/rust/issues/144755
Ensure we codegen the main fn
This fixes two bugs. The one that was identified in the linked issue is that when we have a `main` function, mono collection didn't consider it as an extra collection root.
The other is that since CGU partitioning doesn't know about the call edges between the entrypoint functions, naively it can put them in different CGUs and mark them all as internal. Which would result in LLVM just deleting all of them. There was an existing hack to exclude `lang = "start"` from internalization, which I've extended to include `main`.
Fixes https://github.com/rust-lang/rust/issues/144052
Insert checks for enum discriminants when debug assertions are enabled
Similar to the existing null-pointer and alignment checks, this checks for valid enum discriminants on creation of enums through unsafe transmutes. Essentially this sanitizes patterns like the following:
```rust
let val: MyEnum = unsafe { std::mem::transmute<u32, MyEnum>(42) };
```
An extension of this check will be done in a follow-up that explicitly sanitizes for extern enum values that come into Rust from e.g. C/C++.
This check is similar to Miri's capabilities of checking for valid construction of enum values.
This PR is inspired by saethlin@'s PR
https://github.com/rust-lang/rust/pull/104862. Thank you so much for keeping this code up and the detailed comments!
I also pair-programmed large parts of this together with vabr-g@.
r? `@saethlin`
