Rustc dev guide sync #15
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This was renamed by rust-lang#116791.
* Fix some broken links under bootstrapping. * Fix more broken links for bootstrapping.
rust-lang#1960) * compiletest: specify which special env var and which particular CI job * compiletest: fix grammar and add link to Dockerfile
Signed-off-by: needsure <[email protected]>
The `-Z verbose` option has been renamed to `-Z verbose-internals` in commit b5d8361 [1] (PR rust-lang#119129 [2]). This commit updates the remaining `-Z verbose` to `-Z verbose-internals`. [1]: rust-lang@b5d8361 [2]: rust-lang#119129
Co-authored-by: Tshepang Mbambo <[email protected]>
Signed-off-by: onur-ozkan <[email protected]>
"Query-field" should be "Query-fied" - three instances.
* region-outlives propagation * woops * gamer
* Add a couple of linkcheck exceptions: Addresses: ``` Server returned 500 Internal Server Error for https://github.com/rust-lang/rust/pulls?q=is%3Apr+label%3AS-inactive+is%3Aclosed Server returned 401 Unauthorized for https://objects.githubusercontent.com/github-production-release-asset-2e65be/343907537/60cd5880-7b81-11eb-9502-68d5f473ebe2?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=releaseassetproduction%2F20241103%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20241103T085906Z&X-Amz-Expires=300&X-Amz-Signature=e532fd7d2bd271f12988982bc8e5a47a0f966b40452b55d444bbb74292ac1fb1&X-Amz-SignedHeaders=host&response-content-disposition=attachment%3B%20filename%3Drustc.generic.wpaProfile&response-content-type=application%2Foctet-stream Server returned 500 Internal Server Error for https://github.com/rust-lang/rust/pulls?q=is%3Apr+label%3AS-inactive ``` * Skip only github.com/rust-lang/rust/pulls?q=
… skipping of link-checking (rust-lang#2023) * Remove properly tracked config file from .gitignore The file is part of the git history and is a configuration file. Fixes: rust-lang#2018 * Add env. variable support * Refactoring * Really skip linkcheck if requested
…-lang#2179) This level of detail in the dev guide is a maintenance burden; better to leave this sort of thing to in-tree comments.
This makes it less of a hassle to render the book locally.
Kobzol
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Sep 15, 2025
match clang's `va_arg` assembly on arm targets tracking issue: rust-lang#44930 For this example ```rust #![feature(c_variadic)] #[unsafe(no_mangle)] unsafe extern "C" fn variadic(a: f64, mut args: ...) -> f64 { let b = args.arg::<f64>(); let c = args.arg::<f64>(); a + b + c } ``` We currently generate (via llvm): ```asm variadic: sub sp, sp, #12 stmib sp, {r2, r3} vmov d0, r0, r1 add r0, sp, #4 vldr d1, [sp, #4] add r0, r0, #15 bic r0, r0, #7 vadd.f64 d0, d0, d1 add r1, r0, #8 str r1, [sp] vldr d1, [r0] vadd.f64 d0, d0, d1 vmov r0, r1, d0 add sp, sp, #12 bx lr ``` LLVM is not doing a good job. In fact, it's well-known that LLVM's implementation of `va_arg` is kind of bad, and we implement it ourselves (based on clang) for many targets already. For arm, our own `emit_ptr_va_arg` saves 3 instructions. Next, it turns out it's important for LLVM to explicitly start and end the lifetime of the `va_list`. In rust-lang#146059 I already end the lifetime, but when looking at this again, I noticed that it is important to also start it, see https://godbolt.org/z/EGqvKTTsK: failing to explicitly start the lifetime uses an extra register. So, the combination of `emit_ptr_va_arg` with starting/ending the lifetime makes rustc emit exactly the instructions that clang generates:: ```asm variadic: sub sp, sp, #12 stmib sp, {r2, r3} vmov d16, r0, r1 vldr d17, [sp, #4] vadd.f64 d16, d16, d17 vldr d17, [sp, #12] vadd.f64 d16, d16, d17 vmov r0, r1, d16 add sp, sp, #12 bx lr ``` The arguments to `emit_ptr_va_arg` are based on [the clang implementation](https://github.com/llvm/llvm-project/blob/03dc2a41f3d9a500e47b513de5c5008c06860d65/clang/lib/CodeGen/Targets/ARM.cpp#L798-L844). r? ``@workingjubilee`` (I can re-roll if your queue is too full, but you do seem like the right person here) try-job: armhf-gnu
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