This patch adds a new field bool Is64bit in DWARFYAML::Data to indicate the address size of target. It's helpful for inferring the AddrSize in some DWARF sections.
It looks reasonable to me.
I'd suggest to do in the next way:
uint8_t AddrSize; if (DebugRanges.AddrSize) AddrSize = *DebugRanges.AddrSize; else AddrSize = DI.Is64bit ? 8 : 4;
I am not an expert in MachO, but should MachO::FAT_MAGIC_64 and MachO::FAT_CIGAM_64 also be tested?