On Mon, Dec 07, 2020 at 09:56:56AM -0800, Nick Desaulniers wrote: > On Mon, Dec 7, 2020 at 4:23 AM Michael Ellerman <m...@ellerman.id.au> wrote: > > So is clang defining __powerpc64__ even for 32-bit code? > > > > And the answer appears to be yes: > > > > $ clang --version > > Ubuntu clang version 11.0.0-2 > > Target: powerpc64le-unknown-linux-gnu > > > > $ clang -m32 -dM -E - < /dev/null | grep powerpc > > #define __powerpc64__ 1 > > #define __powerpc__ 1 > > > > Compare to gcc: > > > > $ gcc --version > > gcc (Ubuntu 10.2.0-13ubuntu1) 10.2.0 > > > > $ gcc -m32 -dM -E - < /dev/null | grep powerpc > > #define __powerpc__ 1 > > #define powerpc 1 > > #define __powerpc 1 > > > > > > Which is fairly problematic, because we use the presence/absence of > > __powerpc64__ to determine if we're building 64-bit/32-bit code in > > several places. > > > > Not sure what the best approach for fixing that is. > > Thanks for the triage; we should fix our preprocessor: > https://bugs.llvm.org/show_bug.cgi?id=48427
Not only is that a compatibility problem (as the bug report says): it is a straight up violation of the ABI! (For ELFv2, which you have here; older ABIs did not mention the preprocessor predefines, but this was exactly the same on all compilers afaik.) Segher
