On Thu, Aug 31, 2017 at 01:41:47AM +0800, Simon Guo wrote: > Hi Seth, > On Wed, Aug 30, 2017 at 08:05:25AM -0500, Seth Forshee wrote: > > With gcc 7 from Ubuntu 17.10 I'm getting the follwing error building the > > ptrace selftests for powerpc: > > > > ptrace-tm-vsx.c: In function ‘tm_vsx’: > > ptrace-tm-vsx.c:42:2: error: PIC register clobbered by ‘r2’ in ‘asm’ > > asm __volatile__( > > ^~~ > > make[1]: *** [ptrace-tm-vsx] Error 1 > > ptrace-tm-spd-vsx.c: In function ‘tm_spd_vsx’: > > ptrace-tm-spd-vsx.c:55:2: error: PIC register clobbered by ‘r2’ in ‘asm’ > > asm __volatile__( > > ^~~ > > make[1]: *** [ptrace-tm-spd-vsx] Error 1 > > ptrace-tm-spr.c: In function ‘tm_spr’: > > ptrace-tm-spr.c:46:2: error: PIC register clobbered by ‘r2’ in ‘asm’ > > asm __volatile__( > > ^~~ > > > > Best I can tell gcc now considers any inline asm which clobbers r2 an > > error, and I get it even with -fno-pic. I'm not familiar with powerpc > > asm, but it's not obvious to me why r2 is in the clobber list for any of > > these. > Thanks for reporting this issue. > > In PPC ABI, r2 is used as TOC pointer and it might be changed by inter-module > function calls. I believe that is the reason why it was put into clobber list > originally. > > In our case, dual entry is used to save TOC pointer (r2) update for function > calls within one module. There is no r2 change and I think r2 can be moved > out > of clobber list. > > I don't have a GCC-7 environment. If possible, could you help to try > following > patch?
Your patch fixes the build errors for me. Thanks! Seth
