It seems that -mapcs-frame is going away: https://gcc.gnu.org/ml/gcc-patches/2015-01/msg01001.html However, I cannot find any combination of options without -mapcs-frame or -mapcs which will at least maintain the full four registers (pc, lr, sp, fp) in the stack frame. The reason I'm wanting that is that at least for perf in linux, they way the kernel performs a userspace backtrace is to look up the saved lr register in each frame (see for example in linux arch/arm/kernel/perf_callchain.c). But without -mapcs-frame there is no guarantee that anything will be saved. What is the right switch to use in the future to ensure that the four registers are in each frame?
