On 06/20/2017 12:05 AM, Jeff Law wrote: > On 06/19/2017 03:56 PM, Joseph Myers wrote: >> On Mon, 19 Jun 2017, Florian Weimer wrote: >> >>> I think architectures such as aarch64 without implied stack probing as >>> part of the function call sequence would benefit most from an ABI >>> agreement (splitting the probing responsibility in some way between >>> caller and callee). For architectures with some form of implied >> >> I'd expect that, regardless of architecture, if calls don't write to the >> stack, the caller has to save its own return address somewhere before >> making a call, which means writing the saved link register.
> True, but the callee doesn't know the offset where the caller saved the > return address. In fact, different callers could have stored it at > different offsets. AFAICT for these targets we just have to make a > worst case assumption about the caller. There are also some weird corner cases like this one: H. Baker, “CONS Should Not CONS Its Arguments, Part II: Cheney on the M.T.A.” <http://home.pipeline.com/~hbaker1/CheneyMTA.html>. So I think some sort of convention is needed here. Thanks, Florian
