On 10/23/18 11:40, Nick Desaulniers wrote: > On Mon, Oct 22, 2018 at 10:11 PM Nadav Amit <na...@vmware.com> wrote: >> >> at 5:37 PM, Nathan Chancellor <natechancel...@gmail.com> wrote: >> >> Commit 77b0bf55bc67 ("kbuild/Makefile: Prepare for using macros in >> inline assembly code to work around asm() related GCC inlining bugs") >> added this flag to KBUILD_CFLAGS, where it works perfectly fine with >> GCC. However, when building with Clang, all of the object files compile >> fine but the build hangs indefinitely at init/main.o, right before the >> linking stage. Don't include this flag when building with Clang. >> >> The kernel builds and boots to a shell in QEMU with both GCC and Clang >> with this patch applied. >> >> Link: >> https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FClangBuiltLinux%2Flinux%2Fissues%2F213&data=02%7C01%7Cnamit%40vmware.com%7C871daebc2ca44947d28d08d638811fb5%7Cb39138ca3cee4b4aa4d6cd83d9dd62f0%7C1%7C0%7C636758524579997650&sdata=shuxW81QRrO3TSqbgf462wgZYdLeAKeQEdGRxmnUX30%3D&reserved=0 >> Signed-off-by: Nathan Chancellor <natechancel...@gmail.com> >> --- >> >> The reason this patch is labeled RFC is while I can verify that this >> fixes the issue, I'm not entirely sure why the '-Wa,-' works for GCC >> and not Clang. I looked into what the flag means and I couldn't really >> find anything so I just assume it's taking input from stdin? The issue >> could stem from how GCC forks gas versus how Clang does it. If this >> isn't of concern and the maintainers are happy with this patch as is, >> feel free to take it. >>
Perhaps someone could actually, you know, time the build and see how much -pipe actually matters, if at all? -hpa