rnk added inline comments.
================ Comment at: src/UnwindRegistersRestore.S:98 + # skip fs + # skip gs + movq 56(%rcx), %rsp # cut back rsp to new location ---------------- mstorsjo wrote: > mstorsjo wrote: > > compnerd wrote: > > > Doesn't Win64 ABI require some of the MMX registers be saved/restored too? > > Right, yes, xmm6-xmm15 should be backed up and restored. I'll try to amend > > this with such a change. > Actually, such a change doesn't necessarily make much sense on its own. > > As long as the dwarf encoding itself doesn't describe how to restore those > registers (and on unix platforms you don't need to, so it probably isn't even > specified), you'd just end up backing up the xmm registers on entry when > throwing the exception, and restoring the exactly same ones again - it only > guards against changes within libcxxabi/libunwind and the unwinding machinery > itself, not against changes further down in the call stack between the > thrower and catcher of the exception. > > So with that, I guess this patch is futile unless planning to extend the > x86_64 dwarf handling in llvm to include those registers as well - and that's > a little out of scope of what I intended to do here... If we have XMM values in the register context, we might as well reload them here. I assume libunwind will switch away from DWARF and over to UNWIND_INFO opcodes in the near future, and that will give us an accurate register context. https://reviews.llvm.org/D38819 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
