Allows customization of builtin functions under FatLTO #119348
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Place compiler_builtins at the end. After that we check if any crate wants to customize the builtin functions. Remove the function of compiler_builtins, if any.
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I don't think I'm the best person to review this. |
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r? @nikic |
jannic
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Dec 29, 2023
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I'm not qualified to review this pull request, but I tried it out and can verify that it fixes #118609 in a simple real-world scenario (compiling https://github.com/rp-rs/rp2040-project-template). |
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The associated PR has been reverted in #119885. |
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Fixes #118609.
Currently, we are using LTO in a way that is similar to LLVM's legacy LTO. This approach does not allow the caller to decide which symbol to use. LLVM's new LTO puts symbol resolution in the hands of the caller.
This PR uses a similar approach to the new LTO to select the appropriate builtin symbol. I'm not dealing with the weak symbol in the inline asm. But this can also be done with
.lto_discard. I'm not sure it's worth implementing it.r? @bjorn3