Use protected visibility by default on ELF platforms #105518
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A-linkage
Area: linking into static, shared libraries and binaries
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
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bjorn3
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Those issues are about which symbols are exported or not. This issue is not about which symbols are exported or not. Protected visibility will still export symbols. It merely prevents overwriting those symbols from other dylibs. |
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Ah ok thanks for the clarification! |
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Attempted to implement this in https://github.com/bjorn3/rust/tree/protected_visibility. It works fine for ld.gold and ld.lld, but with ld.bfd it results in: |
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@bjorn3 did you report the issue upstream to Binutils? This would be a nice thing to have. |
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I didn't. I don't even know if the latest binutils has the same issue. |
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I just published a blog post on this topic: https://davidlattimore.github.io/posts/2024/08/27/rust-dylib-rabbit-holes.html The situation has improved significantly with GNU ld from binutils 2.40 and later, which went into distros late last year. I'd say that we can't justify breaking linking for users that have GNU ld < 2.40 for quite some time. So that means this would need to be behind a flag. The good news is that we could consider defaulting that flag to true when LLD is selected as the linker. I'm happy to have a go at this, unless @bjorn3 or someone else wants to? |
This was referenced Sep 5, 2024
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This might be a bit unexpected, so I'm posting it for your information. |
matthiaskrgr
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Oct 1, 2024
… r=Urgau Replace -Z default-hidden-visibility with -Z default-visibility Issue rust-lang#105518
rust-timer
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Oct 1, 2024
Rollup merge of rust-lang#130005 - davidlattimore:protected-vis-flag, r=Urgau Replace -Z default-hidden-visibility with -Z default-visibility Issue rust-lang#105518
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I noticed that the .so files built by x.py contain a lot of "unnecessary" PLT entries. The compiler should be using protected visibility on ELF platforms by default.
I was thinking we should be able to tie it to
#[no_mangle]but on Zulip @bjorn3 proposed tying it to the SymbolExportLevel (Rust for mangled and unmangled but not exported from cdylib#[rustc_std_internal_symbol]symbols and C for#[no_mangle]symbols).The text was updated successfully, but these errors were encountered: