Anyone got any numbers/info on the impact to LTO optimizations? Some brief googling shows mold does support LTO, but is it as good/better than what you'll find in the LLVM/GCC linkers?
LTO for LLVM/clang and gcc is implemented by getting the compiler to emit internal compiler IR code rather than machine code to the object files. The linker's job is to call into the compilers at link time with the serialized IR code from the object files to produce machine code; the linker does not do the link-time optimization itself. Therefore LTO support in a linker is a pretty binary feature (does it support X compiler on Y platform?) without much of a "good/better" gradation. And when it comes to that, mold implements LTO support for both gcc and LLVM on Unix-like systems.
