Add profiling of bootstrap commands using Chrome events
Since we now have support for tracing in bootstrap, and the execution of most commands is centralized within a few functions, it's quite trivial to also trace command execution, and visualize it using the Chrome profiler. This can be helpful both to profile what takes time in bootstrap and also to get a visual idea of what happens in a given bootstrap invocation (since the execution of external commands is usually the most interesting thing).
This is how it looks:
I first tried to use [tracing-flame](https://github.com/tokio-rs/tracing/tree/master/tracing-flame), but the output wasn't very useful, because the event/stackframe names were bootstrap code locations, instead of the command contents.
r? ``@jieyouxu``
valtree performance tuning
Summary: This PR makes type checking of code with many type-level constants faster.
After https://github.com/rust-lang/rust/pull/136180 was merged, we observed a small perf regression (https://github.com/rust-lang/rust/pull/136318#issuecomment-2635562821). This happened because that PR introduced additional copies in the fast reject code path for consts, which is very hot for certain crates: 6c1d960d88/compiler/rustc_type_ir/src/fast_reject.rs (L486-L487)
This PR improves the performance again by properly interning the valtrees so that copying and comparing them becomes faster. This will become especially useful with `feature(adt_const_params)`, so the fast reject code doesn't have to do a deep compare of the valtrees.
Note that we can't just compare the interned consts themselves in the fast reject, because sometimes `'static` lifetimes in the type are be replaced with inference variables (due to canonicalization) on one side but not the other.
A less invasive alternative that I considered is simply avoiding copies introduced by https://github.com/rust-lang/rust/pull/136180 and comparing the valtrees it in-place (see commit: 9e91e50ac5 / perf results: https://github.com/rust-lang/rust/pull/136593#issuecomment-2642303245), however that was still measurably slower than interning.
There are some minor regressions in secondary benchmarks: These happen due to changes in memory allocations and seem acceptable to me. The crates that make heavy use of valtrees show no significant changes in memory usage.
Parallel-compiler-related cleanup
Parallel-compiler-related cleanup
I carefully split changes into commits. Commit messages are self-explanatory. Squashing is not recommended.
cc "Parallel Rustc Front-end" https://github.com/rust-lang/rust/issues/113349
r? SparrowLii
``@rustbot`` label: +WG-compiler-parallel
Update books
## rust-lang/book
1 commits in e2fa4316c5a7c0d2499c5d6b799adcfad6ef7a45..d4d2c18cbd20876b2130a546e790446a8444cb32
2025-02-12 16:22:54 UTC to 2025-02-12 16:22:54 UTC
- Fix example for `cargo fix` (rust-lang/book#4226)
## rust-lang/reference
3 commits in de2d5289e45506b11dd652bef4f99de64be70e1c..6195dbd70fc6f0980c314b4d23875ac570d8253a
2025-02-12 15:40:30 UTC to 2025-02-11 20:35:17 UTC
- Revert "Update function-pointer.md for stabilization of `extended_varargs_abi_support`" (rust-lang/reference#1734)
- Rework error handling in mdbook-spec (rust-lang/reference#1733)
- `as` cast improvements (rust-lang/reference#1732)
Mark condition/carry bit as clobbered in C-SKY inline assembly
C-SKY's compare and some arithmetic/logical instructions modify condition/carry bit (C) in PSR, but there is currently no way to mark it as clobbered in `asm!`.
This PR marks it as clobbered except when [`options(preserves_flags)`](https://doc.rust-lang.org/reference/inline-assembly.html#r-asm.options.supported-options.preserves_flags) is used.
Refs:
- Section 1.3 "Programming model" and Section 1.3.5 "Condition/carry bit" in CSKY Architecture user_guide:
9f7121f7d4/CSKY%20Architecture%20user_guide.pdf
> Under user mode, condition/carry bit (C) is located in the lowest bit of PSR, and it can be
accessed and changed by common user instructions. It is the only data bit that can be visited
under user mode in PSR.
> Condition or carry bit represents the result after one operation. Condition/carry bit can be
clearly set according to the results of compare instructions or unclearly set as some
high-precision arithmetic or logical instructions. In addition, special instructions such as
DEC[GT,LT,NE] and XTRB[0-3] will influence the value of condition/carry bit.
- Register definition in LLVM:
https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/CSKY/CSKYRegisterInfo.td#L88
cc ```@Dirreke``` ([target maintainer](aa6f5ab18e/src/doc/rustc/src/platform-support/csky-unknown-linux-gnuabiv2.md (target-maintainers)))
r? ```@Amanieu```
```@rustbot``` label +O-csky +A-inline-assembly
dev-guide: Link to `t-lang` procedures for new features
I was confused in https://github.com/rust-lang/rust/pull/136867, because while I did remember that such a procedure existed, but I couldn't seem to find it in the dev guide.
Rollup of 8 pull requests
Successful merges:
- #134981 ( Explain that in paths generics can't be set on both the enum and the variant)
- #136698 (Replace i686-unknown-redox target with i586-unknown-redox)
- #136767 (improve host/cross target checking)
- #136829 ([rustdoc] Move line numbers into the `<code>` directly)
- #136875 (Rustc dev guide subtree update)
- #136900 (compiler: replace `ExternAbi::name` calls with formatters)
- #136913 (Put kobzol back on review rotation)
- #136915 (documentation fix: `f16` and `f128` are not double-precision)
r? `@ghost`
`@rustbot` modify labels: rollup
i686-linux-android: increase CPU baseline to Pentium 4 (without an actual change
As per ``@maurer's`` [comment](https://github.com/rust-lang/rust/issues/136495#issuecomment-2648743078), this shouldn't actually change anything since we anyway add a bunch of extensions that bump things up way beyond Pentium 4. But Pentium 4 is consistent with the other i686 targets and I don't know enough about the exact sequence of CPU generations to be confident with more than this. ;)
Add amdgpu target
Add amdgpu target to rustc and enable the LLVM target.
Fix compiling `core` with the amdgpu:
The amdgpu backend makes heavy use of different address spaces. This
leads to situations, where a pointer in one addrspace needs to be casted
to a pointer in a different addrspace. `bitcast` is invalid for this
case, `addrspacecast` needs to be used.
Fix compilation failures that created bitcasts for such cases by
creating pointer casts (which creates an `addrspacecast` under the hood)
instead.
MCP: https://github.com/rust-lang/compiler-team/issues/823
Tracking issue: #135024
Kinda related to the original amdgpu tracking issue #51575 (though that one has been closed for a while).
tree-wide: parallel: Fully removed all `Lrc`, replaced with `Arc`
tree-wide: parallel: Fully removed all `Lrc`, replaced with `Arc`
This is continuation of https://github.com/rust-lang/rust/pull/132282 .
I'm pretty sure I did everything right. In particular, I searched all occurrences of `Lrc` in submodules and made sure that they don't need replacement.
There are other possibilities, through.
We can define `enum Lrc<T> { Rc(Rc<T>), Arc(Arc<T>) }`. Or we can make `Lrc` a union and on every clone we can read from special thread-local variable. Or we can add a generic parameter to `Lrc` and, yes, this parameter will be everywhere across all codebase.
So, if you think we should take some alternative approach, then don't merge this PR. But if it is decided to stick with `Arc`, then, please, merge.
cc "Parallel Rustc Front-end" ( https://github.com/rust-lang/rust/issues/113349 )
r? SparrowLii
`@rustbot` label WG-compiler-parallel
Document minimum supported host tooling on macOS
In particular we support macOS 10.12 (same as for binaries produced by `rustc`) and Xcode 9.2 (the highest Xcode version that runs on macOS 10.12.6). I have this installed on a MacBook Pro from 2013 that sits below my desk, and am occasionally testing it.
I am documenting this now because it was unclear in https://github.com/rust-lang/rust/issues/136523.
(I'm not inherently against bumping these one day, but that's a separate discussion, let's at least document what we support right now).
`@rustbot` label O-macos
