On Fri, Jul 10, 2015 at 10:02:06AM +0100, Richard Earnshaw wrote: > This isn't going to reliably work for ARM or AArch64. If the only call > within a leaf function is via the ASM the compiler doesn't guarantee to > ensure the stack is aligned to the ABI requirements.
Those archs have a link register, which is clobbered by the call, so asm doing a call should have the link register in its clobber list, which is enough to prevent shrink-wrapping the asm. Does that also help aligning the stack (as a side effect?) The problem you mention is not target-specific, and would also happen without shrink-wrapping. Maybe forcing a frame pointer (which they do in the reported case) helps? But there certainly could exist ABIs where it does not. This is arch-dependent code by nature, but still. Nastiness :-) Segher
