There have been several mentions on mailing lists about missing atomic
functions in our system libraries (e.g. __atomic_load_8 and
friends), and recently I also saw __bswapdi2 and __bswapsi2
We already have these as source files in our libcompiler_rt
Makefile.inc, but currently:
- The atomic.c file is only enabled for 32 bit PowerPC, and only for clang (since gcc apparently already has it?). This was added by @alfredo in D22549 and committed by @jhibbits in rS356104.
- The bswap[ds]i C implementations are only enabled for mips and riscv, apparently because "on some archs gcc 6.3 requires them".
- The bswap[ds]i assembly implementations are only enabled for arm.
I think it would be nice to just always make both the atomic builtins
and the bswap functions available in our libcompiler_rt, at least in the
.a file. That would probably solve quite a lot of user complaints about
not being to able to compile ports, and having them switch to gcc
Note that with respect to compiler-rt's atomic.c, I am not totally
convinced that its implementation will work in all possible situations,
but having it it better than nothing...