Re:FreeBSD Can Now Be Built From Linux/macOS Hosts, Transiti...
by Someone on Thursday October 22, 2020 @01:10PM
(#24860369)
One factor used to be that constant folding can be problematic. The target platform may have different-precision doubles, or have a different way to represent them (fairly unlikely, nowadays, but back in the time, if you wanted to cross-compile to x87, you needed the ability to compute with its 80-bit doubles.
Another that the compiler may use platform tools (assembler, linker) to build binaries, and those tools they may need a library (say one for writing ELF binaries) that isn’t available. All of them can be ported, but that can be a lot of work for a limited number of users.
Moreover, those users typically have (access to) the target hardware, as they have to be able to test the end result. So, a ‘normal’ compiler may not be optimal, but still be good enough for them.
Because of that, you tend to see more cross-compilers the slower the target hardware.
Another that the compiler may use platform tools (assembler, linker) to build binaries, and those tools they may need a library (say one for writing ELF binaries) that isn’t available. All of them can be ported, but that can be a lot of work for a limited number of users.
Moreover, those users typically have (access to) the target hardware, as they have to be able to test the end result. So, a ‘normal’ compiler may not be optimal, but still be good enough for them.
Because of that, you tend to see more cross-compilers the slower the target hardware.