omjavaid added inline comments.
================ Comment at: lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp:543 + bool contains_sve_reg_data = + (data_sp->GetByteSize() > (reg_data_min_size + GetSVEHeaderSize())); + ---------------- omjavaid wrote: > DavidSpickett wrote: > > I'm a bit dubious about these size checks as a way to tell if things are > > present, should this one have `GetRegisterInfo().IsSVEEnabled()` also? > > > > I'm thinking what if PAC plus MTE plus <random future ext> adds enough > > registers to exceed the size of the SVE header, but the process doesn't in > > fact have SVE. > > > > You could do the size checks in terms of bytes left to read from the > > data_sp, that might simplify it some too. > We are not sure if SVE was enabled or not when we restore. So size checks is > the only way we can figure out if a register checkpoint was created when SVE > was enabled. This works for now but if we have to stack another register set > which is greater than size of SVE header then we will have to put information > about enabled register sets inside the checkpoint maybe in a bitmap > describing which register set is enabled and look for those at predefined > offsets. I thought this wasn't needed for now and will over complicate > already complicated variable sized checkpoint. Just to shed more light on this if SVE is note enabled we just have GPR + FPR + MTE predictable from size. As MTE is just 8 bytes we can be sure if checkpoint has data beyond FPR which is greater than GPR + FPR + SVE_HEADER that means we atleast have SVE header present. Then we check if its a valid header using !sve_vl_valid(m_sve_header.vl)) check and write it to configure SVE registers size before writing actual registers. If we dont have register data beyond greater than GPR+FPR+MTE then we can safely say there is no SVE present at all. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D108739/new/ https://reviews.llvm.org/D108739 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
