On Fri, Jan 27 2017, Robinson, Paul wrote: >> So, from a DWARF perspective, you'd expect that all libraries shall be >> recompiled when migrating from an older x86-64 CPU to a newer one that >> has AVX-512? Or, as in the z/Architecture case, from a zEC12 to a z13 >> system? You don't consider it valid for old and new binaries to coexist >> in the same program? > > I'd expect that the DWARF consumer will understand what the target for > the original executable was, and interpret any DWARF expressions > appropriately. > > My understanding is that AVX and AVX-512 were considered to expand the > vector registers at the most-significant-bit end, not the LSB end. > https://en.wikipedia.org/wiki/Advanced_Vector_Extensions > This allows the same DWARF register numbers to be reused and counting > bits from the LSB end works regardless of the register width.
Correct. So DWARF happens to support this scenario without any translation. That's what I mean by *supporting* "register growth". > I'm not able to find equivalent comparison of the z/Architecture > models, but if they do something similar then it should all Just Work. And that's the point: the first 16 vector registers of z13 are expansions of the existing FP registers at the *LSB* end. So, unfortunately, it does not just work. -- Andreas _______________________________________________ Dwarf-Discuss mailing list Dwarf-Discuss@lists.dwarfstd.org http://lists.dwarfstd.org/listinfo.cgi/dwarf-discuss-dwarfstd.org
