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Rollup merge of #136608 - kulst:ptx_target_features, r=bjorn3

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Pass through of target features to llvm-bitcode-linker and handling them

When using the llvm-bitcode-linker (`linker-flavor=llbc`) target-features are not passed through and are not handled by it.
The llvm-bitcode-linker is mainly used as a self contained linker to link llvm bitcode for the nvptx64 target. It uses `llvm-link`, `opt` and `llc` internally. To produce a `.ptx` file of a specific ptx-version it is necessary to pass the version to llc with the `--mattr` option. Without explicitly setting it, the emitted `.ptx`-version is the minimum supported version of the `--target-cpu`.

I would like to be able to explicitly set the ptx version as [some llvm problems only occur in earlier `.ptx`-versions](https://github.com/llvm/llvm-project/issues/112998).

Therefore this pull request adds support for passing target features to llvm-bitcode-linker and handling them.
I was not quite sure if adding these features to `rustc_target/src/target_features.rs` is necessary or not. If so I will gladly add these.

    r? ``@kjetilkjeka``
This commit is contained in:
Jubilee
2025-02-20 14:58:17 -08:00
committed by GitHub
parent 921ef32467 831d9f39e9
commit 6d74563b20
5 changed files with 26 additions and 2 deletions
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6
compiler/rustc_codegen_ssa/src/back/link.rs
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@@ -2519,6 +2519,12 @@ fn add_order_independent_options(
"--target-cpu",
&codegen_results.crate_info.target_cpu,
]);
if codegen_results.crate_info.target_features.len() > 0 {
cmd.link_arg(&format!(
"--target-feature={}",
&codegen_results.crate_info.target_features.join(",")
));
}
} else if flavor == LinkerFlavor::Ptx {
cmd.link_args(&["--fallback-arch", &codegen_results.crate_info.target_cpu]);
} else if flavor == LinkerFlavor::Bpf {