如何更改默认的 rustc/Cargo 链接器? [英] How do I change the default rustc / Cargo linker?

问题描述

我想让 rustc 在特定的 crate 中使用 lld 作为链接器而不是 ld.所以我在我的项目目录中创建了 .cargo/config ，内容如下:

I would like to make rustc use lld as a linker instead of ld in a particular crate. So I create .cargo/config in my project directory with the following:

[target.x86_64-unknown-linux-gnu]                                                                   
linker = "ld.lld"

导致链接器错误的原因:

Which leads to linker errors:

$ cargo build
...
  = note: ld.lld: error: unable to find library -ldl
          ld.lld: error: unable to find library -lrt
          ld.lld: error: unable to find library -lpthread
          ld.lld: error: unable to find library -lgcc_s
          ld.lld: error: unable to find library -lc
          ld.lld: error: unable to find library -lm
          ld.lld: error: unable to find library -lrt
          ld.lld: error: unable to find library -lpthread
          ld.lld: error: unable to find library -lutil
          ld.lld: error: unable to find library -lutil

与 rust-lld 相同.如果我设置 linker = "ld"(这应该是默认值，对吧?)，我就得到

Same thing with rust-lld. If I set linker = "ld" (which should be the default, right?), I just get

  = note: ld: cannot find -lgcc_s

我尝试手动解决所有丢失的库(使用 -C link-arg=--library-path=/usr/lib/x86_64-linux-gnu 等)，但它只会导致错误的链接和段错误的二进制文件.

I tried to resolve all the missing libraries manually (with -C link-arg=--library-path=/usr/lib/x86_64-linux-gnu and the like), but it only lead to wrong linkage and a segfaulting binary.

有趣的是，如果我将 /usr/bin/ld 替换为 /usr/bin/ld.lld 的符号链接，它运行良好(没有错误，并且从编译后的二进制文件中我看到它确实与 lld 链接).但是，我不想让 lld 成为我的系统范围的链接器，我只想在特定的 Rust crate 中使用它.

Interestingly enough, if I replace /usr/bin/ld with a symlink to /usr/bin/ld.lld, it works great (no errors, and from the compiled binary I see that it was indeed linked with lld). However, I don't want to make lld my system-wide linker, I just want to use it in a particular Rust crate.

那么更改默认 rustc 链接器的正确方法是什么?

So what is the proper way to change the default rustc linker?

推荐答案

感谢@Jmb 的评论，我找到了解决方案.事实证明，rustc 使用的默认链接器实际上是 cc(这是有道理的 - 它提供了编译/链接 C 代码所需的所有默认值，这也适用于 Rust).我们可以向 cc 传递一个参数，使其与 lld 链接:

Thanks to @Jmb comment, I found a solution. Turns out that the default linker that rustc uses is actually cc (which makes sense - it supplies all the needed defaults to compile/link C code, which also work for Rust). We can pass an argument to cc to make it link with lld:

[target.x86_64-unknown-linux-gnu]
rustflags = [
    "-C", "link-arg=-fuse-ld=lld",
]

现在 cargo build 与 lld 链接.

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