I'm trying to make my iOS app smaller (the code section of the binary is 70 MB) by using thumb instructions. There seems to be a good amount of discussion around using the thumb version of armv7, e.g. here: http://wanderingcoder.net/2010/07/19/ought-arm/ . However, I can't find very much about arm64 + Thumb. Is it even possible? If so, how can I have clang compile that way?
From the ARMv8 Reference Manual, §A1.3.2 (p. A1-35):
AArch64 state supports only a single instruction set, called A64. This is a fixed-length instruction set that uses 32-bit instruction encodings.
So no, 64-bit Thumb is not a thing.