The original reproducibility fix was problematic for a couple reasons:
- disabling both lto and parallel builds had an unfortunate effect of nearly
doubling rust-native and rust build times (which are slow to begin with).
Disabling lto hurts runtime performance too.
- both of these things were done for the *entire build*, while the only
problematic item is the librustdoc crate.
- lto=off option in config.toml has an effect only on building rustc
(the compiler itself), and doesn't help with rustdoc reproducibility.
Actual fix is the codegen-units setting, which indirectly disables
lto via giving llvm only one unit to work with at a time.
After some digging, here's a more targeted fix for the problem.
Why librustdoc is non-reproducible, but not anything else
remains a mystery, hidden deep in rust-llvm's lto optimization code.
(From OE-Core rev: a1977407a88a2004c3a6d2dba1d5bfe1aa1664b2)
Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
ce5428f48a