Cannot link to --crate-type staticlib as -whole-archive

[krdln]

Background: I was trying to integrate libfoo.a (compiled as crate-type = "staticlib") as a static depencency of libbar.so library (written in C++). Turned out that bazel was passing -whole-archive libfoo.a to the linker, which caused problems:

Steps to reproduce

This is a slightly different scenario, but produces the same error:

touch foo.rs
rustc --crate-type staticlib foo.rs
ld -r -whole-archive libfoo.a -o foo.o

Fails with (both with ld and ld.gold):

libfoo.a(clzsi2.o): In function `__clzsi2':
clzsi2.c:(.text.__clzsi2+0x0): multiple definition of `__clzsi2'
libfoo.a(compiler_builtins-05f9079cfd1746c1.compiler_builtins.5xigqg70-cgu.0.rcgu.o):/cargo/registry/src/github.com-1ecc6299db9ec823/compiler_builtins-0.1.5/src/int/mod.rs:332: first defined here

Failing version

rustc 1.34.0-nightly (4b1e39b7b 2019-02-05)
GNU ld (GNU Binutils for Ubuntu) 2.30
GNU gold (GNU Binutils for Ubuntu 2.30) 1.15
Ubuntu 18.04

Last working versions

This scenario works without errors on stable (1.32) and beta (1.33.0-beta.6).

---

I don't actually understand linkers enough to even say if that's a bug or expected behaviour, but at least for me it's a regression, because a scenario that was working on stable has stopped to work on nightly.

[nagisa]

This is probably expected. The two different archives contain two definitions of the same compiler-provided function and both compilers are right in including that.

[cdetrio]

I ran into the same issue when using nightly (downgrading to stable fixed it).

[MackieLoeffel]

I am running into the same problem and my current workaround is to remove clzsi2.o from the static library before linking it into a shared library:

touch foo.rs
rustc +nightly --crate-type staticlib foo.rs
ar d libfoo.a clzsi2.o # without this line I get the linker error from above
ld -r -whole-archive libfoo.a -o foo.o

@nagisa I don't understand what you mean with two different compilers. What other compiler than rustc do you mean? The problem seems to me that rustc puts two versions of __clzsi2 into libfoo.a.

[kleisauke]

It look like this is fixed with rust-lang/compiler-builtins@752e35a which is available within Rust 1.36.0 (#60841).

Note that the above mentioned workaround only needs to be applied to Rust 1.35.0 and 1.34.0, otherwise it will cause linker errors. See for example:
https://gitlab.gnome.org/GNOME/librsvg/issues/485#note_549519

[petrochenkov]

I have submitted an RFC about supporting whole archive - rust-lang/rfcs#2951.

[petrochenkov]

Closing this issue, the whole-archive modifier was implemented about 9 months ago, and #93901 now intends to make it available on stable.