Cross-language link-time optimization

[SakiiCode]

Motivations

Rust has support for cross-language LTO called Linker-plugin-based LTO and it can further decrease binary size with minimal configuration. Not only ESP-IDF could benefit from it but also every other Rust crate that pulls in C code.

Solution

Unfortunately it needs clang as the C compiler and linker. I saw that ldproxy only supports gcc and simply replacing it with clang or linker-flavor=ld.lld gives a lot of unrecognized command line options. I only tried the Xtensa architecture so far.

Has anyone experimented with this? Is it possible to change the linker to clang and pass -flto=full to the compiler? Can I read somewhere about why ldproxy had to be created?

Alternatives

Add clang support for ldproxy

Additional context

In my testing this can make a 15% reduction in binary size

If this is too difficult to implement or does not belong here, feel free to close this issue