[llvm-dev] llc generating code that writes below the stack pointer on darwin/x86-64

[Jonas Maebe via llvm-dev]

On 13/11/16 18:48, Stephen Checkoway wrote:
>
>> On Nov 13, 2016, at 11:12, Jonas Maebe via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>>
>> This code use a negative stack offset, which is forbidden on x86-64 (there's no red zone). This happens with llc from llvm 3.7, 3.8 and 3.9.
>
> Doesn't Darwin use the System V ABI [1]? As I understand it, there's a 128-byte red zone on x86-64.

You're right, sorry. I got a crash in this routine, saw the negative 
stack offset, quickly searched to check whether there was a red zone, 
and from a summary of a found page assumed there wasn't, but the quoted 
section was about the Win64 ABI.

I'll have to look further to determine what caused the actual crash.

Thanks,


Jonas