[MaskRay]

Thanks for mentioning nasm.

Both GNU assembler and LLVM integrate assembler parse and match instructions only once. hey then store an internal representation in memory and perform fixed-point iteration. The section/fragment representation gives a lot of flexibility.

In contrast, nasm parses and matches instructions multiple times depending on the optimization level. It also assigns addresses during parsing and uses an ad-hoc method for JMP/JCC instructions. The end conditions of the fixed-point iteration algorithm (global_offset_changed and stall_count) seem unconventional. -O0 does not "relax all" short jumps to near jumps.