Allow injecting a profiler runtime into `#![no_core]` crates
An alternative to #133300, allowing `-Cinstrument-coverage` to be used with `-Zbuild-std`.
The incompatibility between `profiler_builtins` and `#![no_core]` crates appears to have been caused by profiler_builtins depending on core, and therefore conflicting with core (or minicore).
But that's a false dependency, because the profiler doesn't contain any actual Rust code. So we can just mark the profiler itself as `#![no_core]`, and remove the incompatibility error.
---
For context, the error was originally added by #79958.
inject_panic_runtime(): Avoid double negation for 'any non rlib'
<details>
<summary>This PR originally did more things .Click to expand to see.</summary>
By not trying to inject a profiler runtime when only building an rlib. This logic already exists for the panic runtime.
This makes
RUSTFLAGS="-Cinstrument-coverage" cargo build -Zbuild-std=std,profiler_builtins
work. Note that you probably also need
`RUST_COMPILER_RT_FOR_PROFILER=$src/llvm-project/compiler-rt` in your environment.
cc #79401
# Demonstration
Before this fix you get these errors:
```console
$ rm -rf target ; RUST_COMPILER_RT_FOR_PROFILER=/home/martin/src/llvm-project/compiler-rt RUSTFLAGS="-Cinstrument-coverage" cargo +nightly build --release -Zbuild-std=std,profiler_builtins
error: `profiler_builtins` crate (required by compiler options) is not compatible with crate attribute `#![no_core]`
error[E0152]: found duplicate lang item `manually_drop`
= note: first definition in `core` loaded from /home/martin/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-d453bab70303062c.rlib
= note: second definition in the local crate (`core`)
```
With the fix the build succeeds:
```console
$ rm -rf target ; RUST_COMPILER_RT_FOR_PROFILER=/home/martin/src/llvm-project/compiler-rt RUSTFLAGS="-Cinstrument-coverage" cargo +stage1 build --release -Zbuild-std=std,profiler_builtins
Finished `release` profile [optimized] target(s) in 45.57s
```
And we can check code coverage. My example program looks like this:
```rs
fn main() {
if std::env::args_os().nth(1) == Some("write-file".into()) {
std::fs::write("hello.txt", "Hello, world!").unwrap();
} else {
println!("Hello, world!");
}
}
```
when the program prints to stdout:
```
$ LLVM_PROFILE_FILE=stdout.profraw ./target/release/hello-world
Hello, world!
```
we can see that `fs::write()` is not being used (note the `0`'s):
```console
$ /home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/bin/llvm-profdata merge -sparse stdout.profraw -o stdout.profdata
$ /home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/bin/llvm-cov show target/release/hello-world --sources /home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/src/rust/library/std/src/fs.rs --instr-profile stdout.profdata --color | grep -A 3 'pub fn write(&mut self, write: b
ool) -> &mut Self {'
1357| 0| pub fn write(&mut self, write: bool) -> &mut Self {
1358| 0| self.0.write(write);
1359| 0| self
1360| 0| }
```
but when we print to a file:
```console
$ LLVM_PROFILE_FILE=file.profraw ./target/release/hello-world write-file
```
the code coverage shows `fs::write()` as being used (note the `1`'s):
```console
$ /home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/bin/llvm-profdata merge -sparse file.profraw -o file.profdata
$ /home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/bin/llvm-cov show target/release/hello-world --sources /home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/src/rust/library/std/src/fs.rs --instr-profile file.profdata --color | grep -A 3 'pub fn write(&mut self, write: bool) -> &mut Self {'
1357| 1| pub fn write(&mut self, write: bool) -> &mut Self {
1358| 1| self.0.write(write);
1359| 1| self
1360| 1| }
```
</summary>
[AIX] change system dynamic library format
Historically on AIX, almost all dynamic libraries are distributed in `.a` Big Archive Format which can consists of both static and shared objects in the same archive (e.g. `libc++abi.a(libc++abi.so.1)`). During the initial porting process, the dynamic libraries are kept as `.a` to simplify the migration, but semantically having an XCOFF object under the archive extension is wrong. For crate type `cdylib` we want to be able to distribute the libraries as archives as well.
We are migrating to archives with the following format:
```
$ ar -t lib<name>.a
lib<name>.so
```
where each archive contains a single member that is a shared XCOFF object that can be loaded.
the behavior of the type system not only depends on the current
assumptions, but also the currentnphase of the compiler. This is
mostly necessary as we need to decide whether and how to reveal
opaque types. We track this via the `TypingMode`.
Over in Zed we've noticed that loading crates for a large-ish workspace can take almost 200ms. We've pinned it down to how rustc searches for paths, as it performs a linear search over the list of candidate paths. In our case the candidate list had about 20k entries which we had to iterate over for each dependency being loaded.
This commit introduces a simple FilesIndex that's just a sorted Vec under the hood. Since crates are looked up by both prefix and suffix, we perform a range search on said Vec (which constraints the search space based on prefix) and follow up with a linear scan of entries with matching suffixes.
FilesIndex is also pre-filtered before any queries are performed using available target information; query prefixes/sufixes are based on the target we are compiling for, so we can remove entries that can never match up front.
Overall, this commit brings down build time for us in dev scenarios by about 6%.
100ms might not seem like much, but this is a constant cost that each of our workspace crates has to pay, even when said crate is miniscule.
[StableMIR] API to retrieve definitions from crates
Add functions to retrieve function definitions and static items from all crates (local and external).
For external crates, we're still missing items from trait implementation and primitives.
r? ````@compiler-errors:```` Do you know what is the best way to retrieve the associated items for primitives and trait implementations for external crates? Thanks!
Add functions to retrieve function definitions and static items from
all crates (local and external).
For external crates, add a query to retrieve the number of defs in a
foreign crate.
Remove support for `-Zprofile` (gcov-style coverage instrumentation)
Tracking issue: #42524
MCP: https://github.com/rust-lang/compiler-team/issues/798
---
This PR removes the unstable `-Zprofile` flag, which enables ”gcov-style” coverage instrumentation, along with its associated `-Zprofile-emit` configuration flag.
(The profile flag predates and is almost entirely separate from the stable `-Cinstrument-coverage` flag.)
Notably, the `-Zprofile` flag:
- Is largely untested in-tree, having only one run-make test that does not check whether its output is correct or useful.
- Has no known maintainer.
- Has seen no push towards stabilization.
- Has at least one severe regression reported in 2022 that apparently remains unaddressed.
- #100125
- Is confusingly named, since it appears to be more about coverage than performance profiling, and has nothing to do with PGO.
- Is fundamentally limited by relying on counters auto-inserted by LLVM, with no knowledge of Rust beyond debuginfo.
We haven't been compressing dylib metadata for a while now. Removing
decompression support will regress error messages about an incompatible
rustc version being used, but dylibs are pretty rare anyway.
Try to point out when edition 2024 lifetime capture rules cause borrowck issues
Lifetime capture rules in 2024 are modified to capture more lifetimes, which sometimes lead to some non-local borrowck errors. This PR attempts to link these back together with a useful note pointing out the capture rule changes.
This is not a blocking concern, but I'd appreciate feedback (though, again, I'd like to stress that I don't want to block this PR on this): I'm worried about this note drowning in the sea of other diagnostics that borrowck emits. I was tempted to change the level of the note to `.span_warn` just so it would show up in a different color. Thoughts?
Fixes#130545
Opening as a draft first since it's stacked on #131183.
r? `@ghost`
Depend on rustc_abi in compiler crates that use it indirectly but have
not yet taken on that dependency, and are not entangled in my other PRs.
This leaves an "excise rustc_target" step after the dust settles.
Then we can rename the _raw functions to drop their suffix, and instead
explicitly use is_stable_const_fn for the few cases where that is really what
you want.
Retire the `unnamed_fields` feature for now
`#![feature(unnamed_fields)]` was implemented in part in #115131 and #115367, however work on that feature has (afaict) stalled and in the mean time there have been some concerns raised (e.g.[^1][^2]) about whether `unnamed_fields` is worthwhile to have in the language, especially in its current desugaring. Because it represents a compiler implementation burden including a new kind of anonymous ADT and additional complication to field selection, and is quite prone to bugs today, I'm choosing to remove the feature.
However, since I'm not one to really write a bunch of words, I'm specifically *not* going to de-RFC this feature. This PR essentially *rolls back* the state of this feature to "RFC accepted but not yet implemented"; however if anyone wants to formally unapprove the RFC from the t-lang side, then please be my guest. I'm just not totally willing to summarize the various language-facing reasons for why this feature is or is not worthwhile, since I'm coming from the compiler side mostly.
Fixes#117942Fixes#121161Fixes#121263Fixes#121299Fixes#121722Fixes#121799Fixes#126969Fixes#131041
Tracking:
* https://github.com/rust-lang/rust/issues/49804
[^1]: https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/Unnamed.20struct.2Funion.20fields
[^2]: https://github.com/rust-lang/rust/issues/49804#issuecomment-1972619108
Stabilize the `map`/`value` methods on `ControlFlow`
And fix the stability attribute on the `pub use` in `core::ops`.
libs-api in https://github.com/rust-lang/rust/issues/75744#issuecomment-2231214910 seemed reasonably happy with naming for these, so let's try for an FCP.
Summary:
```rust
impl<B, C> ControlFlow<B, C> {
pub fn break_value(self) -> Option<B>;
pub fn map_break<T>(self, f: impl FnOnce(B) -> T) -> ControlFlow<T, C>;
pub fn continue_value(self) -> Option<C>;
pub fn map_continue<T>(self, f: impl FnOnce(C) -> T) -> ControlFlow<B, T>;
}
```
Resolves#75744
``@rustbot`` label +needs-fcp +t-libs-api -t-libs
---
Aside, in case it keeps someone else from going down the same dead end: I looked at the `{break,continue}_value` methods and tried to make them `const` as part of this, but that's disallowed because of not having `const Drop`, so put it back to not even unstably-const.
Implement RFC3695 Allow boolean literals as cfg predicates
This PR implements https://github.com/rust-lang/rfcs/pull/3695: allow boolean literals as cfg predicates, i.e. `cfg(true)` and `cfg(false)`.
r? `@nnethercote` *(or anyone with parser knowledge)*
cc `@clubby789`
Refactoring to `OpaqueTyOrigin`
Pulled out of a larger PR that uses these changes to do cross-crate encoding of opaque origin, so we can use them for edition 2024 migrations. These changes should be self-explanatory on their own, tho 😄
